Disposition of Cesium-137 Contaminated Emission Control Dust and Other Incident-Related Material; Final Staff Technical Position

NUCLEAR REGULATORY COMMISSION

Disposition of Cesium-137 Contaminated Emission Control Dust and

Other Incident-Related Material; Final Staff Technical Position

AGENCY: U.S. Nuclear Regulatory Commission.

ACTION: Notice: final staff technical position.

-----------------------------------------------------------------------

SUMMARY: The U.S. Nuclear Regulatory Commission is issuing guidance, in

the form of a technical position, that may be used, in case-by-case

requests, by appropriate licensees, to dispose of a specific incident-

related mixed waste. Mixed waste is a waste that not only is

radioactive, but also is classified as hazardous under the Resource

Conservation and Recovery Act (RCRA). The specific mixed waste

addressed in this position is emission control dust from electric arc

furnaces (EAFs) or foundries that has been contaminated with cesium-137

(\137\Cs). The contamination results from the inadvertent melting of a

\137\Cs source that: (1) Has been improperly disposed of by an NRC or

Agreement State licensee; (2) has been commingled with the steel scrap

supply; (3) has not been detected as it progresses to the steel-

producing process; and (4) is volatilized in the production process and

thereby can and has contaminated large volumes of emission control dust

and the emission control systems at steel-producing facilities.

The position, which has been coordinated with the U.S.

Environmental Protection Agency (EPA), provides the possibility of a

public health-protective, environmentally sound, and cost-effective

alternative for the disposal of a large part of this mixed waste, much

of which contains \137\Cs in concentrations similar to values that

frequently occur in the environment. The position provides the bases

that, with the approval of appropriate regulatory authorities (e.g.,

State-permitting agencies) and others (e.g., disposal site operators),

and with possible public input, could be used to allow disposal of

stabilized waste at Subtitle C, RCRA-permitted, hazardous waste

disposal facilities. NRC believes that disposal, under the provisions

of the position or other acceptable alternatives, is preferable to

allowing this mixed waste to remain indefinitely at steel company

sites.

The position has been developed through an open public process in

which working draft documents have been routinely shared with EPA, and

also placed in NRC's Public Document Room to allow interested party

access. NRC published the proposed position in the Federal Register for

comment (61 FR 1608, dated January 22, 1996). NRC is now publishing the

entire final position, together with its responses to the comments

received.

FOR FURTHER INFORMATION CONTACT: Dominick A. Orlando, Division of Waste

Management, Office of Nuclear Material Safety and Safeguards, Mail Stop

TWFN 8F-37, U.S. Nuclear Regulatory Commission, Washington, DC 20555,

Telephone (301) 415-6749.

SUPPLEMENTARY INFORMATION:

Disposition of Cesium-137 Contaminated Emission Control Dust and Other

Incident-Related Materials; Branch Technical Position

A. Introduction

Emission control (baghouse) dust and other incident-related

materials (e.g., clean-up materials or recycle process streams)

contaminated with \137\Cs 1 are currently being stored as mixed

radioactive and hazardous waste at several steel company sites across

the country. At any single site, this material typically contains a

total \137\Cs quantity ranging downward from a little more than 1 curie

(Ci) or 37 gigabecquerels (GBq) of activity, distributed within several

hundred to a few thousand tons of iron/zinc-rich dust, as well as

within much smaller quantities of clean-up or dust-recycle, process-

stream materials. In current situations, most, but not all, of this

material would be classified as mixed waste and this technical position

is intended as a potential disposition alternative for this incident-

related material.2

---------------------------------------------------------------------------

\1\ The byproduct material \137\Cs does not include the \137\

Cs, from global fallout, that exists in the environment from the

testing of nuclear explosive devices (see Footnote 3).

\2\ The term, ``incident-related material,'' is frequently used

in this position to refer to the total spectrum of \137\Cs-

contaminated materials resulting from an inadvertent melting event.

Because of its widespread use in radioactive devices and its

volatility when subjected to steel melting temperatures, the

position is directed solely at incident-related materials involving

this radioisotope.

---------------------------------------------------------------------------

Typically, the radioactivity is not evenly distributed among the

incident-related materials. Rather, a small fraction (e.g., one-tenth)

of the material contains most (e.g., 95 percent) of the radioactivity.

Most of the material contains a small quantity of radioactivity at low

concentrations and makes up most of the mixed waste, incident-related

material volume. This material is classified as hazardous waste under

RCRA because it contains lead, cadmium, and chromium which are common

to the recycle metal supply. The \137\Cs contamination of this

hazardous waste results from a series of three principal events: (1)

The loss of control of a radioactive source by an NRC or an Agreement

State licensee; (2) the inclusion of the source within the recycle

metal scrap supply used by the steel producers; and (3) the inability

to screen out the radioactive source as it progresses along the typical

scrap collection-to-melt pathway (including radiation detectors used at

most furnaces, foundries and many ferrous metal recycling facilities).

Consequently, irrespective of the quantity or concentration of the

radioactivity, most of the current material is subject to joint

regulation as mixed waste under RCRA and the Atomic Energy Act of 1954,

as amended, or the equivalent law of an Agreement State.

[[Page 13177]]

The disposal options for these materials, specifically the large

volumes of material with the lower concentrations of \137\Cs, have been

limited because of their ``mixed-waste'' classification and the costs

associated with the disposition of large volumes of mixed or

radioactive waste. Long-term solutions addressing the control and

accountability of licensed radioactive sources are being considered by

NRC and Agreement States. Solutions addressing the disposition of mixed

wastes are being considered by various Federal and State regulatory

authorities and the U.S. Department of Energy. Nevertheless, the

Commission believes that, pending decisions on improved licensee

accountability and the ultimate disposition of mixed waste, appropriate

disposal of the existing incident-related, mixed-waste material is

preferable to indefinite onsite storage.

As a result, this technical position defines the bases that the NRC

staff would find acceptable for: (1) Authorizing a licensee, possessing

\137\Cs-contaminated emission control dust and other incident-related

materials (e.g., the steel company or its service contractor), to

transfer treated \137\Cs-contaminated material, below levels specified

in this position, to a Subtitle C, RCRA-permitted hazardous waste

disposal facility; and (2) not licensing the possession and disposal of

these incident-related materials by the RCRA-permitted disposal

facility. The position does not address disposal at a Subtitle D

facility. Because of its radioactivity (i.e., \137\Cs concentration

levels), some of the incident-related material may not be suitable for

disposal at a Subtitle C, RCRA-permitted disposal facility. This

material may be disposed of either: (a) at a licensed low-level

radioactive waste disposal facility after appropriate treatment of its

hazardous constituents; or (b) at a mixed-waste disposal facility, if

applicable acceptance criteria are met.

The regulatory basis for the action is found at 10 CFR

20.2001(a)(1) and 20.2002. The first paragraph authorizes a licensee to

dispose of licensed material as provided in the regulations in 10 CFR

Parts 30, 40, 60, 61, 70, or 72. Paragraph 30.41(b) states the

conditions under which licensees are allowed to transfer byproduct

material. Paragraph 30.41(b)(7) of Part 30 specifically provides that

licensees may transfer byproduct material if authorized by the

Commission, in writing. In the case of the \137\Cs-contaminated

material, the licensing action under 10 CFR 20.2002 would constitute

the written authorization required by paragraph 30.41(b)(7).

It should be noted that additional acceptance requirements, beyond

those covered in this NRC position for disposal of \137\Cs-contaminated

incident-related waste at a Subtitle C RCRA-permitted disposal

facility, may be established by: (1) An Agreement State; (2) the permit

conditions or policies of the RCRA-permitted disposal facility; (3) the

regulatory requirements of the RCRA disposal facility's permitting

agency; or (4) other authorized parties, including State and local

governments. These requirements may be more stringent than those

covered in the guidance described in this technical position. The

licensed entity transferring the \137\Cs-contaminated incident-related

materials must consult with these parties, and obtain all necessary

approvals, in addition to those of NRC and/or appropriate Agreement

States, for the transfers defined in this technical position. Nothing

in this position shall be or is intended to be construed as a waiver of

any RCRA permit condition or term, of any State or local statute or

regulation, or of any Federal RCRA regulation. The position applies to

both hazardous and non-hazardous incident-related waste as specifically

defined. In addition, the conditions established in this position

pertain to NRC staff and licensee actions. Therefore, in those

instances where an Agreement State is the sole regulatory authority for

the radioactive material, the Agreement State has the option of using

this guidance in reviewing requests for the disposal of the material.

B. Discussion

Over the past decade, there has been an increasing number of

instances in which radioactive material has been inadvertently

commingled with scrap metal that subsequently has entered the steel-

recycle production process. If this radioactive material is not removed

before the melting process, it could contaminate the finished metal

product, associated dust-recycle process streams, equipment

(principally air effluent treatment systems), and the dust generated

during the process. Some of the contaminant radioactivity is a result

of naturally occurring radionuclides that are deposited in oil and gas

transmission piping. Other radioactivity may be associated with

radioactive sources that are contained in industrial or medical

devices. In this latter case, the commingling of the radioactive source

with metal destined for recycling can occur if the regulatorily

required accountability of these sources fails and a radioactive source

is included within the metal scrap supply used by the steel producers.

In cases where the radionuclide is naturally occurring, or is already

present in the environment as a result of global fallout, the

inadvertent melting of a radioactive source could increase the

contaminant concentration above that caused by these background

environmental levels.3

---------------------------------------------------------------------------

\3\ In a letter to William Guerry, Jr. from NRC's Executive

Director for Operations, James M. Taylor, dated May 25, 1993, NRC

made a preliminary determination that \137\Cs levels in baghouse

dust can reasonably be attributed to fallout from past nuclear

weapons testing, if concentrations are less than about 2 pCi/g

(0.074 Bq/g).

---------------------------------------------------------------------------

Although many of the steel producers have installed equipment to

detect incoming radioactivity, this equipment cannot provide absolute

protection because of the shielding of radioactive emissions that may

be provided by uncontaminated scrap metal or the shielded ``pig'' that

contains the radioactive source. Of special concern, because of the

nature and magnitude of the involved radioactivity, are NRC- or

Agreement State-licensed sources containing \137\Cs.

When \137\Cs sources are inadvertently melted with a load of scrap

metal, a significant amount of the \137\Cs activity contaminates the

metal-rich dust that is collected in the highly efficient emission

control systems that steel mills have installed to comply with air

pollution regulations. Because of hazardous constituents--specifically

lead, cadmium, and chromium--EAF emission control dust is a listed

waste, KO61, which is subject to regulation under RCRA. If this dust

becomes contaminated with \137\Cs, the resulting material is classified

as a mixed waste. Emission control dust, generated immediately after

the melting of a \137\Cs source with the scrap metal, can contain

cesium concentrations in the range of hundreds or thousands of

picocuries per gram (pCi/g) or a few to a few tens of becquerels (Bq)

per gram of dust, above typical levels in dust caused by \137\Cs in the

environment (e.g., 2 pCi/g or 0.074 Bq/g). Several thousand cubic feet

(several tens of cubic meters) of dust could be contaminated at these

levels. Dust generated days or weeks after a melt of a source

(containing hundreds of millicuries or a few curies of \137\Cs

(37 GBq)) will contain reduced concentrations, typically

less than 100 pCi/g (3.7 Bq/g).

Even after extensive decontamination and remediation activities,

newly generated dust may still contain concentrations greater than 2

pCi/g (0.074 Bq/g) background levels, but generally less than 10 pCi/g

(0.37 Bq/g). When the melting of a source is not immediately detected,

materials related

[[Page 13178]]

to downstream processes have also been contaminated with relatively low

concentrations of \137\Cs (e.g., 10 pCi/g (0.37 Bq/g)). In addition,

materials used during decontamination may also be contaminated with

dust containing \137\Cs concentrations at similar levels above

background.

As the result of past inadvertent meltings of \137\Cs sources, a

number of steel producers possess a total of about 10,000 tons (9000

metric tons) of incident-related materials, most of which contains

\137\Cs concentrations of less than 100 pCi/g (3.7 Bq/g). This material

is typically being stored onsite because of the lack of disposal

options that are considered cost-effective by the steel

companies.4 It is the disposition of material at these

concentration levels that is the subject of this technical position.

---------------------------------------------------------------------------

\4\ In April 1995, Envirocare of Utah, Inc., an operator of a

mixed-waste disposal site, received authorization from the State of

Utah and initiated operations to treat and dispose of \137\Cs-

contaminated incident-related (mixed-waste) materials at

concentrations not exceeding 560 pCi/g (20.7 Bq/g).

---------------------------------------------------------------------------

C. Regulatory Position

General

Because of the ``incident-related'' origin of the \137\Cs-

contaminated materials, the Commission has approved a course of action

that includes: (1) Exploration of approaches to improve licensee

control and accountability to reduce the likelihood of sealed sources

entering the scrap metal supply; (2) cooperation with the steel

manufacturers and other appropriate organizations to identify the

magnitude and character of the problem (with particular emphasis on

improving the capability to detect sealed sources before their

inadvertent melting); and (3) development of interim guidelines for the

disposal of \137\Cs contaminated dust and other incident-related

materials (the subject of this technical position).

Specific

Bases for Allowing Transfer and Possession of 137Cs-Contaminated,

Incident-Related Material

The bases for allowing transfer and possession of \137\Cs-

contaminated emission control dust and other incident-related

materials, under the provisions of existing regulations, are as

follows: (1) Any person at a Subtitle C, RCRA-permitted disposal

facility involved with the receipt, movement, storage, or disposal of

contaminated materials should not receive an exposure greater than 1

millirem (mrem) or 10 microsievert (Sv) per year (i.e., one-

hundredth of the dose limit for individual members of the public as

defined at 10 CFR 20.1301(A)(1)), above natural background levels;

5; (2) members of the general public in the vicinity of storage or

disposal facilities should not receive exposures and no individual

member of the public should be likely to receive a dose greater than 1

mrem (10 Sv) per year above background as a result of any and

all transfers and disposals of contaminated materials; (3) handling or

processing of the contaminated materials, undertaken as a result of its

radioactivity, should not compromise the effectiveness of permitted

hazardous waste disposal operations; (4) treatment of contaminated

materials must be accomplished by persons operating under a licensee's

radiation protection program (note that the licensee can be the steel

facility or the entity that treats the incident-related material,

either on- or offsite); and (5) transportation of contaminated

materials will be subject to U.S. Department of Transportation (DOT)

regulations and, as applicable, transportation of contaminated,

hazardous materials must be performed by hazardous material employees,

as defined in DOT regulations (49 CFR Part 172, Subpart H).

---------------------------------------------------------------------------

\5\ The use of 1 mrem/yr (10 Sv/yr) has no significance

or precedential value as a health and safety goal. It was selected

only for the purpose of analysis of the levels at which the

referenced materials could be partitioned to allow the bulk of the

material to be transferred to unlicensed persons. It does not

represent an NRC position on the generic acceptability of dose

levels. Such levels are established only by rule.

---------------------------------------------------------------------------

Definition of Contaminated Materials and Initial Incident Response

A melting event generally necessitates extensive decontamination

and remediation operations at the EAF or foundry (e.g., replacing

refractory bricks and duct work). Subsequent operations include the

proper interim handling and management (e.g., accumulation and

containment) of emission control dust and other incident-related

contaminated materials. Based on a review of several recent incidents,

the dust may contain \137\Cs concentrations up to hundreds or thousands

of pCi/g (a few to a few tens of Bq/g), whereas the other generally

limited-volume, incident-related materials typically contain lower

concentrations. As a result, the initial clean-up and collection/

treatment/packaging of the contaminated emission control dust and other

materials at the EAF or foundry must be performed by an NRC or

Agreement State licensee operating under an approved radiation

protection program. The licensee is also responsible for compliance

with other regulatory requirements (e.g., those of the Occupational

Safety and Health Administration and RCRA Treatment Permitting

requirements).

Provisions for Disposal at a Subtitle C, RCRA-Permitted, Disposal

Facility

Once the decontamination/remediation and collection/treatment/

packaging activities have been completed, one of two paths may be

followed for the disposal of the incident-related materials, dependent

on \137\Cs-concentration levels and whether the final land disposal

operation involves the burial of packaged or unpackaged materials.

1. Packaged Disposal of Treated Waste

On this disposal path, contaminated materials must be treated

through stabilization to comply with all EPA and/or State waste

treatment requirements for land disposal of regulated hazardous

waste.6 The treatment operations must be undertaken by either: (i)

The owner/operator of the EAF or foundry (licensed by NRC or

appropriate Agreement State to possess, treat, and transfer \137\Cs-

contaminated, incident-related materials); or (ii) an NRC- or Agreement

State-licensed service contractor (operating either on- or offsite).

Based on the radiological impact assessment provided in Appendix A, the

licensee could be authorized by NRC or an Agreement State to transfer

the treated incident-related materials to a Subtitle C, RCRA-permitted,

disposal facility, provided that all the following conditions are met:

---------------------------------------------------------------------------

\6\ For non-hazardous material covered by this position,

stabilization equivalent to that provided for hazardous waste would

be necessary.

---------------------------------------------------------------------------

(a) The \137\Cs-contaminated emission control dust and other

incident-related materials are the result of an inadvertent melting of

a sealed source or device;

(b) The emission control dust and other incident-related materials

have been stabilized to meet requirements for land disposal of RCRA-

regulated waste, and have been stored (if applicable) and transferred

in compliance with a radiation protection program as specified at 10

CFR 20.1101;

(c) The total \137\Cs activity, contained in emission control dust

and other incident-related materials to be transferred to a Subtitle C,

RCRA-permitted, disposal facility, has been specifically approved by

NRC or the appropriate Agreement State(s) and does not exceed the total

activity associated with the inadvertent melting incident.

[[Page 13179]]

Moreover, NRC or the appropriate Agreement State will maintain a public

record of the total incident-related \137\Cs activity, received by the

facility over its operating life, to ensure that the total disposed of

\137\Cs activity does not exceed 1 curie (37 GBq); 7

---------------------------------------------------------------------------

\7\ The 1-curie (37-GBq) value represents a reasonable maximum

bounding activity, associated with several incidents, that could be

transferred to an RCRA-permitted facility under the provisions of

this position. It also represents a quantity that would be less than

the activity disposed of over the operating life of the RCRA-

permitted facility if the facility routinely disposed of non-

incident-related emission control dust containing background

concentrations of \137\Cs.

---------------------------------------------------------------------------

(d) The RCRA disposal facility operator has been notified in

writing of the impending transfer of the incident-related materials and

has agreed in writing to receive and dispose of the packaged materials;

8

---------------------------------------------------------------------------

\8\ The NRC staff believes the contract between the licensed

facility and the RCRA facility operator is an appropriate vehicle

for complying with this provision, provided that the contract

specifies the volume of waste, the radionuclide and its average

concentration in the waste in picocuries per gram or becquerels per

gram, the total aggregated amount of radioactive material in the

shipment, the hazardous waste code of the waste, and the EPA

identification number of the RCRA disposal facility receiving the

waste. The NRC staff will evaluate requests for license amendments

to transfer incident-related material based upon the licensee

demonstrating that the RCRA disposal facility operator has agreed to

the transfer and has made provisions to retain the information about

the radioactive material in the waste, along with the information

that is required to be retained by the RCRA facility operator under

40 CFR 263.22.

---------------------------------------------------------------------------

(e) The licensee providing the radiation protection program

required in paragraph (b), notifies, in writing, the Commission or

Agreement State(s) in which the transferor and transferee are located,

of the impending transfer, at least 30 days before the transfer;

(f) The stabilized material has been packaged for transportation

and disposal in non-bulk steel packagings as defined in DOT regulations

at 49 CFR 173.213. (Note that this is a condition established under

this technical position and is not a DOT requirement. Under DOT

regulations, material with concentrations of less than 2000 pCi/g (74

Bq/g) is not considered radioactive);

(g) In any package, the emission control dust and other incident-

related materials, that have been stabilized and packaged as defined in

(b) and (f) above, contain pretreatment average concentrations of

\137\Cs that did not exceed 130 pCi/g (4.8 Bq/g) of material; 9

and

---------------------------------------------------------------------------

\9\ The 130 pCi/g (4.8 Bq/g) value is the concentration, based

on the analysis in the appendix and including a regulatory margin of

1.5, that would result in a calculated potential exposure of less

than 1 mrem (10 Sv). The disposal of incident-related

materials in packaged form allows compliance with this position to

be demonstrated through measurement of \137\Cs concentrations, as

well as direct radiation levels external to the package.

Notwithstanding the redundant approaches to ensure compliance with

the exposure criterion, the regulatory margin of 1.5 has been

included in determining the acceptable measurables defined in the

position.

---------------------------------------------------------------------------

(h) The dose rate at 3.28 feet (1 meter) from the surface of any

package containing stabilized waste does not exceed 20 rem per

hour or 0.20 Sv per hour, above background.10

\10\ At this exposure rate, for the exposure period as defined

in the appendix, total exposure would not exceed 1 mrem (10

Sv) with a regulatory margin of 1.5.

---------------------------------------------------------------------------

Note that, in defining the pretreatment \137\Cs-concentration value

stated in paragraph (1)(g), a factor of 1.5 has been included as a

regulatory margin. This factor adds further assurance to the certainty

in protection provided by the licensee's: (1) Sampling of \137\Cs

concentrations in contaminated materials; (2) measurements of dose rate

external to the disposal (and transportation) packagings; and (3) other

assumptions included in the radiological impacts assessment.

2. Disposal of Unpackaged (i.e., Bulk) Treated Waste

On this disposal path, contaminated materials must also be treated

through stabilization to comply with all EPA and State waste treatment

requirements for land disposal of RCRA-regulated hazardous

waste.11 The treatment operations must be undertaken by either (i)

the owner/operator of the EAF or foundry (licensed to possess, treat,

and transfer 137Cs-contaminated, incident-related materials), or

(ii) a licensed service contractor. Based on the radiological impact

assessment provided in the appendix, the licensee could be authorized

to transfer the stabilized incident-related materials to a Subtitle C,

RCRA-permitted, disposal facility, provided that all the following

conditions are met. (Note that conditions (a) through (e) are identical

to those applicable to packaged disposal of treated waste):

---------------------------------------------------------------------------

\11\ See footnote 6.

---------------------------------------------------------------------------

(a) The 137Cs-contaminated emission control dust and other

incident-related materials are the result of an inadvertent melting of

a sealed source or device;

(b) The emission control dust and other incident-related materials

have been stabilized to meet requirements for land disposal of RCRA-

regulated waste, and have been stored (if applicable), and transferred

in compliance with a radiation protection program as specified at 10

CFR 20.1101;

(c) The total 137Cs activity, contained in emission control

dust and other incident-related materials to be transferred to a

Subtitle C, RCRA-permitted, disposal facility, has been specifically

approved by NRC or the appropriate Agreement State(s) and does not

exceed the total activity associated with the inadvertent melting

incident. Moreover, NRC or the appropriate Agreement State will

maintain a public record of the total incident-related 137Cs

activity, received by the facility over its operating life, to ensure

that the total disposed of 137Cs activity does not exceed 1 curie

(37 GBq); 12

---------------------------------------------------------------------------

\12\ See footnote 7.

---------------------------------------------------------------------------

(d) The RCRA disposal facility operator has been notified in

writing of the impending transfer of the incident-related materials and

has agreed in writing to receive and dispose of these materials;

13

---------------------------------------------------------------------------

\13\ The NRC staff believes the contract between the licensed

facility and the RCRA facility operator is an appropriate vehicle

for complying with this provision, provided that the contract

specifies the volume of waste, the radionuclide and its average

concentration in the waste in picocuries per gram or becquerels per

gram, the total aggregated amount of radioactive material in the

shipment, the hazardous waste code of the waste and the EPA

identification number of the RCRA disposal facility receiving the

waste. The NRC staff will evaluate requests for license amendments

to transfer incident-related material based upon the licensee

demonstrating that the RCRA disposal facility operator has agreed to

the transfer and has made provisions to retain the information about

the radioactive material in the waste along with the information

that is required to be retained by the RCRA facility operator under

40 CFR 263.22.

---------------------------------------------------------------------------

(e) The licensee providing the radiation protection program

required in paragraph (b) notifies, in writing, the Commission or

Agreement State(s) in which the transferor and transferee are located,

of the impending transfer, at least 30 days before the transfer; and

(f) The emission control dust and other incident-related materials,

that have been stabilized as defined in (b) above, contain pretreatment

average concentrations of 137Cs that did not exceed 100 pCi/g (3.7

Bq/g) of material.14

---------------------------------------------------------------------------

\14\ The 100 pCi/g (3.7 Bq/g) value is the concentration, based

on the analysis in the appendix and including a regulatory margin of

2, that would result in a calculated potential exposure of less than

1 mrem (10 Sv). The disposal of incident-related material

in unpackaged (bulk) form dictates that compliance with this

position would be demonstrated through measurement of 137Cs

concentrations. Without the redundant approach to ensure compliance

with the exposure criterion inherent with the packaged-disposal

approach (see footnote 8), the regulatory margin, included in

determining the acceptable measurables defined in the position, has

been increased to 2.0.

---------------------------------------------------------------------------

Note that, in defining the pretreatment 137Cs-concentration value

in paragraph (2)(f), a factor of 2 has been included as a regulatory

margin. The factor adds further assurance to the certainty of

protection provided by the licensee's: (1) Sampling of 137Cs

concentrations in

[[Page 13180]]

contaminated materials; and (2) other assumptions included in the

radiological impacts assessment.

Treatment, Storage, and Transfer of Emission Control Dust or Other

Incident-Related Materials with 137Cs Concentrations

Indistinguishable From Background Levels (i.e., 2 pCi/g (0.074 Bq/g) or

Less)

The EAF or foundry licensed to possess and transfer 137Cs-

contaminated emission control dust, or a licensed service contractor,

is authorized to transfer emission control dust and other incident-

related materials as if they were not radioactive, provided that the

137Cs concentration within the emission control dust and other

incident-related materials is 2 pCi/g (0.074 Bq/g) of material or less.

The foundry or licensed service contractor must determine the

137Cs concentration using the sampling program discussed below.

Aggregation of 137Cs-Contaminated Emission Control Dust and Other

Incident-Related Materials

If applicable, aggregation of 137Cs-contaminated emission

control dust and other incident-related material, before stabilization

treatment, is acceptable if performed in compliance with a radiation

protection program, as described at 10 CFR 20.1101, and provided that:

(1) Aggregation involves the same characteristic or listed

hazardous waste and the wastes must be amenable to and undergo the same

appropriate treatment for land-disposal restricted waste;

(2) Aggregation does not increase the overall total volume nor the

radioactivity of the incident-related waste; and

(3) Materials, when aggregated, are subjected to a sampling

protocol that demonstrates compliance with 137Cs-concentration

criteria on a package-average 15 basis.

---------------------------------------------------------------------------

\15\ The term package, as used here, refers to packages used by

the licensee to transfer the material to the disposal facility,

irrespective of whether this package is also the disposal container.

---------------------------------------------------------------------------

Determination of 137Cs Concentrations and Radiation Measurements

137Cs concentrations may be determined by the licensee by

direct or indirect (e.g., external radiation) measurements, through an

NRC- or Agreement State-approved sampling program. The sampling program

must be sufficient to ensure that 137Cs contamination in the

stabilized emission control dust and in other incident-related

materials, on a package-average basis, is consistent with the

concentration criteria in this technical position. The sampling program

must provide assurance that the quantity of 137Cs in any package

(see footnote 15) does not exceed the product of the applicable

concentration criterion times the net weight of contaminated material

in a package.

Appendix A--Assessment of Radiological Impact of Disposal of

137Cs-Contaminated Emission Control Dust and Other Incident-

Related Materials at a Subtitle C RCRA-Permitted Disposal Facility

1. Background

In the normal process of producing recycled steel, scrap steel

is subjected to a melting process. In this process, most impurities

in the scrap steel are removed and generally contained within

process-generated slag or off-gas. Typically, the off-gas carries

dust, that can contain iron and zinc, together with certain heavy

metals, through an emission control system to a ``baghouse,'' where

the dust is captured in ``bag-type'' filters. Hazardous constituents

within the dust, principally lead, cadmium, and chromium, can cause

the U.S. Environmental Protection Agency (EPA) to designate the dust

as a hazardous waste, under the Resource Conservation and Recovery

Act (RCRA)--often as the listed waste K061.

Typically, when the scrap consists largely of junk automobiles,

the dust contains a high percentage (greater than 20 percent) of

zinc, which can be a valuable recovery product. Moreover, the zinc

recovery process produces slag and other byproducts that have

recycle potential. If economic (e.g., low zinc content) or process

considerations preclude these recycle options, the dust may be

treated and disposed of in a hazardous waste disposal facility. EPA

has specified treatment standards for the various hazardous

constituents of the dust in 40 CFR 268.40. Solidification is the

treatment process typically used to meet these standards. On the

other hand, dust from steel production at basic oxygen furnaces and

open hearth furnaces is excluded from regulation as hazardous waste

(40 CFR 261.4(b)(7)(xvii)).

Because the recycling of steel involves the addition of natural

materials (primarily lime and ferromanganese), very low levels of

radioactivity, ubiquitous in the environment, are involved in the

production process. One of these radionuclides is cesium-137

(\137\Cs) which now occurs in the environment as a result of global

fallout from past weapons-testing programs. \137\Cs has a 30-year

half-life (i.e., a quantity of this radionuclide and its associated

radioactivity will decrease by half every 30 years). The decay of

\137\Cs and its very short-lived daughter produces emissions of beta

particles and gamma rays.

The principal hazard from the beta particles can only be

realized when it enters the human body. The principal hazard from

the gamma rays is as an external source of penetrating radiation

similar to the type of exposure received from an X-ray. Because of

its volatility in the very high-temperature (typically 3000 degrees

fahrenheit or 1650 degrees celsius) steel-making

process, \137\Cs is volatilized and transported in the furnace off-

gas and, as it condenses, becomes a constituent of the emission

control (baghouse) dust. Normal background \137\Cs concentrations in

dust have been measured at picocurie per gram levels (0.024 to 1.23

pCi/g) 1 or thousandths of a becquerel per gram (Bq/g). This

concentration is consistent with the general range of background

levels measured in soils within the United States whereas

concentrations of 10 pCi/g (0.37 Bq/g) are relatively common in

drainage areas.2 As a result of this information, the U.S.

Nuclear Regulatory Commission has determined that \137\Cs

concentrations in emission control dust below 2 pCi/g (0.074 Bq/g)

can be attributed to fallout from past weapons testing.3

---------------------------------------------------------------------------

\1\ A picocurie is one-trillionth of a curie and represents a

decay rate of one disintegration every 27 seconds or 1/27 of a

becquerel.

\2\ Letter to William Lahs, U.S. Nuclear Regulatory Commission,

from Andrew Wallo III, U.S. Department of Energy, dated May 20,

1993.

\3\ Letter from James M. Taylor, NRC, to William Guerry, Jr.,

Collier, Shannon, Rill, and Scott, dated May 25, 1993.

---------------------------------------------------------------------------

2. Statement of Problem

The inadvertent melting of a licensed \137\Cs sealed source with

scrap steel at an electric arc furnace (EAF) or foundry typically

results in the contamination of the steel producer's emission

control system and the generation of potentially large quantities

(e.g., of the order of 1000 tons or 900 metric tons) of \137\Cs-

contaminated emission control dust. Facility cleanup operations will

produce an additional quantity of contaminated material and,

depending on the effectiveness of cleanup operations, further

generation of contaminated dust or cleanup-related materials can

occur. Furthermore, if the occurrence of the melting event is not

immediately detected, contamination can unknowingly be carried

forward with the dust into zinc-recovery process streams. In one

case, for example, this has led to \137\Cs contamination of the

zinc-rich, splash condenser dross residue, referred to as SCDR

material. In the incidents to date, total quantities of these

contaminated materials have not exceeded 2000 tons (1800 metric

tons) per event. The \137\Cs concentration in all these materials

can vary, but in typical past events, much of the material is

contaminated at levels ranging from 2 pCi/g (0.074 Bq/g) to a few

hundred pCi/g (most below approximately 100 pCi/g or 3.7 Bq/g).

Smaller volumes (typically less than 5 percent of the total volume)

have included concentrations at nanocurie/gram levels (thousands of

pCi/g or a few tens of Bq/g).

The intent of this analysis is to characterize the potential

radiological impacts associated with the alternative options for

disposal of \137\Cs-contaminated emission control dust and other

incident-related materials at a Subtitle C, RCRA-permitted facility.

Because RCRA hazardous wastes must be treated to comply with the

requirements for land disposal of restricted waste, the potential

radiological impacts associated with treatment processes required

consideration. To protect against these radiological impacts, the

position includes the provision that treatment of \137\Cs-

contaminated emission control dust and other incident-related

[[Page 13181]]

materials be performed by an NRC or Agreement State licensee. The

licensee would operate, either on- or offsite, under an approved

radiation protection program, as well as any required RCRA treatment

permit. Such controls are necessary because of the wide range of

contaminated materials and their physical forms, together with the

variability in EPA-approved treatment processes. Under this

decision, the Subtitle C, RCRA-permitted disposal facility would be

receiving the emission control dust and other incident-related

materials after their treatment to stabilize the incident-related

material. This stabilized material would be, or would be equivalent

to, the form necessary to stabilize the RCRA-hazardous constituents

(specifically, lead, cadmium, and chromium); that is, a non-

dispersible,4 solid (e.g., cement-type) form. As a result, the

potential radiological hazard from the ``treated'' (stabilized)

material during disposal operations is associated with its

characteristic as an external source of radiation.

---------------------------------------------------------------------------

\4\ In the context used, the term ``non-dispersible'' means that

any radiological impacts from resuspended material are

inconsequential in comparison to the impacts from direct external

exposures resulting from the emission of gamma radiation in the

\137\Cs decay process.

---------------------------------------------------------------------------

After disposal, \137\Cs could only become a hazard through water

pathways if a sufficient quantity and concentration of \137\Cs were

to: (1) Become available, (2) be leached from its solid form, (3) be

released from the disposal facility, and (4) enter a drinking water

supply. No significant radiological hazard would be expected to

result from inadvertent intrusion into the disposed of waste after

facility closure. Notwithstanding the hazard to the intruder from

the hazardous waste constituents, or other hazardous wastes,

constraints placed on the total \137\Cs activity and concentration,

and the waste form, can ensure that radiological exposures would not

exceed those that would be received from residing over commonly

measured background \137\Cs concentrations in the United States (see

discussion under ``Intruder Considerations'').

The following analyses will therefore be directed at an

evaluation of the potential direct, water pathway, and intruder

hazards and will provide a perspective on their significance.

3. Direct Exposure

After the inadvertent melting of a \137\Cs sealed source at an

EAF or foundry, the relatively volatile \137\Cs will leave the

furnace as an offgas and be commingled with the normal emission

control dust. As a result, concentrations of \137\Cs contained in

this dust (and other materials associated with furnace clean-up

operations or subsequent dust recycle process streams) will

increase. Thus, the rate of radiological exposure from this material

will be similar in type, but different in magnitude, than that

received from the typical background levels of \137\Cs. Any change

in magnitude of the exposures to workers at the disposal facility

from this contaminated material when compared to the exposure

received from typical emission control dust would depend on: (1)

Differences in \137\Cs concentrations; (2) variations in the

physical/chemical properties of the materials disposed of; and (3)

changes in worker time-integrated interactions with contaminated

materials.

The three key variables above are particularly important in the

development of this technical position. Of significance to all three

variables, the approach defined in the position calls for treatment

(stabilization) of incident-related materials (to comply with

requirements for land disposal of restricted waste) to take place

``under license,'' at the location where the material was generated,

or at the site of a service contractor who has been permitted for

stabilization treatment of the material either on or off the steel

company site. Complying with the ``Treatment Standards for Hazardous

Wastes,'' defined at 40 CFR 268.40, will result in a solid waste

form from which exposure rates will be smaller than those

originating from the hazardous waste form (e.g., dust) before

treatment. More importantly, treatment of the contaminated

materials, under license, will obviate the need to specifically

address potential treatment-related radiological exposures at

unlicensed, RCRA-permitted, treatment facilities. Thus, under the

approach of this technical position, any minimal exposure to workers

who have not been trained in radiation safety would be limited to

disposal operations.

Furthermore, because the origin of the \137\Cs-contaminated

materials is the result of a melting incident, upper-bound values

can be established for the volume, weight, radioactive material

concentration, and total activity of the contaminated material, on

an incident basis. The base case analysis in this appendix presumes

that the contaminated material involves a volume of 40,000 cubic

feet (1132 cubic meters), a weight of 2000 tons (1800 metric tons),

and a total activity content of less than a 1 curie (Ci) or 37 GBq

of \137\Cs. These values are generally consistent with the

particulars from the incidents that have occurred to date.

Within these constraints, the starting point in the direct

exposure calculation is to estimate the radiation dose rate at a

distance of 3.28 feet (1 meter) from the surface of a semi-infinite

volume (i.e., infinite in areal extent and depth from the point of

exposure) of solidified contaminated material.5 The

calculations assume that the initial \137\Cs contamination in all

untreated dust is 100 pCi/g (3.7 Bq/g). Direct exposure results

scale linearly for other concentration levels, if the waste

configuration is unchanged.

---------------------------------------------------------------------------

\5\ This assessment is generally consistent with the approach

employed in ``Risk Assessment of Options for Disposition of EAF Dust

Following a Meltdown Incident of a Radioactive Cesium Source in

Scrap Steel,'' SELA-9301, Stanley E. Logan, April 1993.

---------------------------------------------------------------------------

Stabilization treatment,6 conducted under a licensed

radiation protection program, is achieved by mixing moist dust with

additives (e.g., liquid reagent to adjust oxidation potential and

portland cement/ fly ash).7 These additives (typically presumed

to add 30 parts by weight to 100 parts of dust or contaminated

material) would result in a solidified product that would contain

\137\Cs concentrations at about 77 percent of initial concentrations

(e.g., 77 pCi/g (2.84 Bq/g)). Because of allowable variations in the

solidification processes (e.g., from the production of granularized

aggregate to solidified monoliths), the bulk density of the

solidified material can range from about 1.4 to 2.5 g/cm3. A

representative dose [rate] conversion factor 8 under these

conditions (calculated at a density of 1.5 g/cm3) would

typically be less than 49 microem/hour (rem/hr) or 0.49

microsieverts/hour (Sv/hr), at a distance of 3.28 feet (1

meter) from the surface of a hypothetical semi-infinite volume of

the solidified material.\9\

---------------------------------------------------------------------------

\6\ In the context of this position, stabilized treatment does

not include either onsite or offsite high-temperature metals

recycling processes.

\7\ This treatment may include the addition of special

stabilization reagents, such as clays, or involve other RCRA-

approved stabilization technologies, that reduce the leachability of

\137\Cs, although the radiological impacts analysis indicates that

such processes are not necessary to protect public health and

safety, and the environment.

\8\ A dose conversion factor represents a value that allows a

radionuclide contamination level to be converted to an estimated

exposure rate.

\9\ The dose rates in this appendix have been calculated through

use of the Microshield computer program, Grove Engineering, Inc.,

version 4.2, 1995. The value of 49 rem (0.49Sv)/

hour represents 0.77 of the 62.9 value shown on Figure 1.

---------------------------------------------------------------------------

Because the quantities of treated dust and other incident-

related materials are not semi-infinite in volume, the actual dose

rate/distance relationships from finite volumes of contaminated

materials will be less. The reduction can be calculated for various

volumetric sources through the use of shape factors. Shape factors

have been calculated for several configurations that are likely to

occur during operations from the time the contaminated treated

material is received at the RCRA-permitted disposal facility through

its disposal. The shape factors can be determined from Figures 1

through 6 for various distances between a specific source

configuration and an exposed individual. Typically, at a distance of

3.28 feet (1 meter), these factors range from about 0.03 to 0.5

(Figures 1 through 5), and have been calculated without accounting

for the limited shielding provided by any packaging. As the distance

from the contaminated materials increases to 9.84 feet (3 meters),

the shape factors for these similar geometries become smaller,

ranging from about 0.004 to 0.2. The largest, likely dose rate

potentially experienced by an individual involved in the disposal

process, measured at 3.28 feet (1 meter), would be from the sides of

large containers or shipments of contaminated materials, and would

be expected to range from about 10 to less than 14 rem/hour

(0.14 Sv/hr) above background (typically 8 to

12rem/hr (0.08 to 0.12 Sv/hr).10 From an open

trench (Figure 4), filled with

[[Page 13182]]

contaminated materials, the calculated dose rate would also be

somewhat less than 13 rem/hr (0.13 Sv/hr) measured

directly over the trench at a 3.28 feet (1 meter) distance. Again,

these values represent 0.77 of the respective values indicated on

the figures because of solidification additives. Figures 6 and 7,

respectively, show the variation in dose rate with the width of the

trench and depth of the waste. Figure 8 is provided to show the

change in dose rate versus the distance offset from the side of the

trailer-type container considered in Figure 3.

---------------------------------------------------------------------------

\10\ The two-thirds loading of the 30-cubic yard box is related

to the typical maximum payload weight that can be transported by

truck without an overweight permit. If the boxes referred to in

Figures 1 and 2 were full, the dose rate would increase by less than

a factor of 1.5. Similarly, if the assumed additive weight percent

(i.e., 30 percent) is varied over a reasonable range from 20 to 40

percent, the resulting dose rate would change in an inversely

proportional manner.

---------------------------------------------------------------------------

A typical disposal rate at a trench within an RCRA-permitted

facility would generally exceed 500 tons (450 metric tons) per

shift.11 Assuming this disposal rate of 500 tons (450 metric

tons) per shift applies to the disposal of treated,137Cs-

contaminated, incident-related material (approximately 20 to 25

truckloads in 8 hours), it would require approximately 4 times this

period of time to dispose of 2000 tons (1800 metric tons). (Note

that the rate of arriving material would likely be dictated by

transportation arrangements, so that the 32 hours required to

dispose of the contaminated material could be spread over several

days or weeks.) Facility workers, therefore, would, on average, only

be exposed to finite volumes of contaminated material for a maximum

period of 32 worker-hours. Applying the highest likely dose rate

(approximately 13 rem/hr (0.13 Sv/hr) from the

side of a trailer containing the contaminated materials), and

presuming exposure at a 3.28-ft (1-meter) distance for the entire

32-hour period, a worker would receive a dose of less than 0.5 mrem

(5 Sv) above background.

---------------------------------------------------------------------------

\11\ Note that if treatment at an RCRA-permitted facility were

required, the limiting operational handling rate for the treated

materials may be limited to 100 to 200 tons (90 to 180 metric tons)

per shift.

---------------------------------------------------------------------------

Qualitatively descriptive time and motion data gathered from

three RCRA-permitted disposal facilities indicate that the above-

calculated dose is conservative for two principal reasons: (1) The

workers having the most significant exposure to materials, from

receipt to disposal, are effectively at greater distances than 3.28

feet (1 meter); and (2) their exposure, at this distance, is over

time periods significantly less than the assumed receipt through

disposal time period of 32 hours. As a result, actual exposures are

expected to be significantly less than 0.5 mrem (5 Sv).

This conservative estimate of potential exposure is based on the

aforementioned time-distance assumptions and is expected to bound

reasonable interactions of disposal facility workers with the

stabilized incident-related materials. For example, incident-related

material could be stored at the disposal site or samples of the

treated material could be subjected to sampling activities. In the

first case, if a 90-day storage period is presumed, the average

exposure distance over the entire period needed to ensure a dose

less than the position's exposure criteria would be on the order of

10 to 20 meters (see Figures 1 through 3, which illustrate the

decrease in dose rate as a function of distance from the source). In

the second case, the typical activity in a 100-g sample would be no

greater than about 10-2 Ci (370 Bq). The dose rate

from such a sample would be less than 0.1 rem/hr (0.001

Sv/hr) at a distance of 1 foot (0.3 meters).

To place the significance of this calculation into perspective,

an estimate can be made of worker exposure from the presumed

handling, treatment, and disposal of normal emission control dust

(i.e., dust that has not been contaminated with 137Cs from a

melted source). This dust would contain background levels of

137Cs (approximately 1 pCi/g (0.037 Bq/g)). Therefore, a worker

interacting with this material at an effective distance of 3.28 feet

(1 meter) over about 300 8-hour shifts (a little more than a working

year) would receive a total maximum exposure of about 0.5 mrem (5

Sv). The magnitude of this exposure is in the same range as

the exposure calculated for the disposal of the contaminated

materials from a single melting event. Moreover, the potential

exposure from the ``melting event'' was estimated under the

extremely conservative assumption that all materials were

contaminated at levels of 100 pCi/g (3.7 Bq/g).

The imposition of a 1-Ci (37-GBq) criterion on the total

incident-related activity that could be disposed of at any one

Subtitle C, RCRA facility (see following discussion on water-pathway

considerations) should further ensure that worker exposures from

137Cs-contaminated emission control dust and other incident-

related materials will not exceed 1 mrem/year (10 Sv/year)

integrated over the lifetime of the facility.

4. Water-Pathway Considerations

The proposed approach to manage 137Cs-contaminated emission

control dust and other incident-related materials presumes licensee

treatment of these materials to comply with requirements for land

disposal of restricted waste. Thus, the radiological, and

potentially hazardous chemical constituents of these materials, will

be incorporated into a stable, solid (e.g., cement-type) form,

similar to that required for routine RCRA-permitted disposal of

emission control dust. As a result, the possibility of 137Cs

presenting a hazard through a water pathway requires consideration

of: (1) the quantity of 137Cs available; (2) the degree to

which the 137Cs could be leached from its waste matrix; and (3)

the extent that any leached 137Cs could migrate into a water

supply.

The disposal of 137Cs in treated emission control dust and

other incident-related materials would be constrained by this policy

to a total activity of 1 Ci (37 GBq). In the previous reference-

basis analysis, an effective concentration, in the treated waste, of

77 pCi/g (2.84 Bq/g) was evaluated--the originally assumed

contaminated material concentration reduced by 30 percent as a

result of the added mass associated with treatment. Both the

quantity and position-defined concentration values place bounds on

any potential water pathway hazard. In the actual wastes that are

subject to potential disposal under the provisions of this position,

the concentration of 137 Cs averaged over all the treated waste

would typically be significantly less than the defined concentration

criteria.

Furthermore, because the 137Cs is contained in a solid

matrix and buried within a facility in which the amount of water

infiltration is minimized, any 137Cs removal from its final

disposal location would be limited while these conditions remain in

effect. The chemistry of any water interacting with the solidified,

137Cs-contaminated waste would also be expected to limit the

leaching process (e.g., avoidance of acidic environments), because

of the controlled nature of the Subtitle C, RCRA-permitted disposal

site and the types and nature (e.g., no liquids) of the wastes

accepted for disposal. Any water that leached 137Cs from the

waste would normally be collected in a leachate collection system at

volumetric concentrations expected to be far less than those

existing in the treated waste. The chemistry of the fill materials

used at the disposal site could also provide a sorbing medium if any

137 Cs leached from the solidified waste. Finally, the location

of Subtitle C, RCRA-permitted disposal sites is such that the source

of any water supply would typically be some distance from the

disposal site.

These chemistry and distance factors are also likely to be major

factors in delaying the arrival of 137Cs at a receptor well

because of retardation effects. This retardation, in terms of its

effect on the time required, under a worst-case scenario, for the

137Cs to reach a water supply, is such that significant

radioactive decay of the 137Cs inventory is likely (the

radioactive half-life of 137Cs is 30 years) before the

137Cs could potentially reach the water supply.

Although qualitative in nature, and based on considerations that

can vary among Subtitle C, RCRA-permitted disposal sites, the

previous discussion has focused on the factors that are likely to

prevent any significant water-pathway hazard. The following, more

quantitative assessment, is provided to conservatively bound any

water-pathway hazard that could potentially occur under extremely

unlikely conditions.

The leachability of 137Cs from any solid waste form that

complies with the land disposal restrictions for the waste's non-

radiological hazardous constituents is likely to be extremely

limited after initial waste placement. After the end of operations

and a post-closure care period of 30 years, a worst-case scenario

presumes that processes take place to degrade the site so that

infiltrating water from the surface passes unimpeded through the

contaminated waste. In predicting the dissolution of 137Cs

under these conditions, a critical process is the partitioning of

the 137Cs that takes place between the waste, soil, and

infiltrating water. Conservatively assuming that the partitioning

from the solid waste form is similar to that from the interstitial

backfill soil to water, an estimate can be made of the amount of

137Cs that can leach into the infiltrating water.

The most important parameter in estimating this transfer, as

well as the subsequent movement of the 137Cs in groundwater, is

the distribution coefficient, ``Kd.'' This parameter expresses

the ratio at equilibrium of 137Cs sorbed onto a given weight of

soil particles to the amount

[[Page 13183]]

remaining in a given volume of water. The higher the value of the

distribution coefficient, the greater the concentration of

137Cs remaining in the soil. The Kd value can be affected

by factors such as soil texture, pH, competing cation effects, soil

porewater concentration, and soil organic matter content.12 For

the non-acidic, sand/clay/soil environments presumed to represent

the RCRA-permitted disposal facilities, a Kd value of 270

milliliter (ml)/g was selected from the Footnote 12 reference as

being appropriate for the subsequent bounding, conservative

analysis.

---------------------------------------------------------------------------

\12\ ``Default Soil Solid/Liquid Partition Coefficients,

Kds, for Four Major Soil Types: A Compendium,'' M. Sheppard and

D. Thibault, Health Physics, Vol. 59, No. 4, October 1990, pp. 471-

482.

---------------------------------------------------------------------------

To model the potential groundwater impacts, the RESRAD 13

code was used. For the representative case, the bounding 40,000

cubic feet (ft \3\) or 1132 cubic meters (m3) of treated

material were presumed to be disposed of in a volume measuring 100-

ft (30.4-m) length x 20-ft (6.09-m) width x 20-ft (6.09-m)

depth. All this material was assumed to contain a 137Cs

concentration of 77 pCi/g (2.84 Bq/g). Notwithstanding the actual

layouts of Subtitle C, RCRA-permitted facilities, a well was

presumed to be located and centered at the downgradient edge of this

specific volume of waste. To maximize the hazard as calculated by

the RESRAD model, the hydraulic gradient was considered to be

parallel to the length of the disposed volume of material.

Infiltration representative of a humid site was presumed and a

minimal unsaturated zone thickness of 3.28 ft (1 m) was assumed to

separate the contaminated zone from the saturated zone. The value

assigned to Kd in the unsaturated zone was 270 ml/g.

Assessments beyond this representative case evaluation are

subsequently discussed.

---------------------------------------------------------------------------

\13\ RESRAD, Version 5.0, Argonne National Laboratory, September

1993.

---------------------------------------------------------------------------

The results from this bounding analysis indicate that drinking

water dose rate would be insignificant (e.g., far less than a

microrem (10-2 Sv) per year). This result is not

surprising because the retardation provided, even in the 3.28-ft (1-

m) deep unsaturated zone and the saturated zone, is sufficient to

preclude drinking water doses for almost 700 years. During this

period, the activity of 137Cs would decay (i.e., be reduced by

radioactive decay) by a factor of about 10 million.

Note that, although it is considered an unrealistic scenario,

the drinking of the leachate directly from the disposal trench after

a period of 30 years would only result in a calculated exposure of

about 7 mrem/year (70 Sv/year).14

---------------------------------------------------------------------------

\14\ This dose estimate is based on comparing leachate

concentrations with the water effluent concentration in 10 CFR Part

20, Appendix B.

---------------------------------------------------------------------------

To consider the effects of a range of parameters, including

other Kd values, on the results of this bounding analysis, the

following analyses are presented. Based on the typical existing

volumes and 137Cs concentrations of incident-related materials,

the imposition of a constraint on 137Cs concentration

effectively bounds the total activity that could be disposed of at a

Subtitle C, RCRA-permitted facility, from a single steel company

site, to a few tens of millicuries (a few GBq).15 Material at

higher concentrations would require disposal at either a mixed-waste

disposal facility or a licensed low-level waste disposal site. Thus,

for the potential disposals at the Subtitle C, RCRA-permitted site

to approach the 1-Ci (37-GBq) incident-related material constraint

in this position, disposals of materials from several incidents

would have to occur. The total volume of material, in this case,

would still represent only a small fraction of an RCRA-permitted

facility's disposal capacity. Repeating the RESRAD analysis

discussed above under these assumptions, but respectively

considering lower Kd values in the contaminated, unsaturated,

and saturated zones, would still result in drinking water doses of

less than 1 mrem (10 Sv) per year unless the Kd values

in all zones approach single-digit values. Even in these cases

(e.g., Kd equal to 2.7), separation of the hypothesized well

location from the disposed material by about 328 feet (100 meters)

would reduce dose rates below 1 mrem (10 Sv) per year

because of the decay of 137 Cs brought about by the increased

retardation times.

---------------------------------------------------------------------------

\15\ For example, the total activity contained in 2000 tons

(1800 metric tons) of material, contaminated at a level of 77 pCi/g

(2.84 Bq/g), would be about 0.14 curies (5.2 GBq). It would be

unlikely that all the material from a particular incident would be

at the maximum concentration defined in the technical position.

---------------------------------------------------------------------------

The concentration constraints in this position, coupled with the

limited number of inadvertent melting situations to which this

position could be applicable, and the case-by-case NRC or Agreement

State approval of the proposed material transfers, are believed to

provide a sufficient basis to ensure protection of public health and

safety, and the environment from water-pathway considerations.

Nevertheless, to provide further protection, should a single

Subtitle C, RCRA-permitted disposal facility accept incident-related

material from more than one incident, the position includes a total

incident-related 137 Cs activity constraint of 1 Ci (37 GBq).

The magnitude of this constraint is based on the typical bounding

activity associated with an inadvertent melting of 137 Cs

sources that have occurred to date at EAFs or foundries. In large

measure, it has been included to provide assurance that the position

is only directed at the ultimate disposition of radioactive material

that exists in the environment as a result of specific inadvertent

melting incidents. However, it also provides a constraint on the

extent of volumetric contamination as a function of concentration.

The practical effect, as previously alluded to, is to limit the

disposal volumes of incident-related contaminated materials to a

small fraction of total disposal site capacity for hazardous waste.

As a result of this volumetric limit, the constraint would further

ensure that any exposures occurring offsite over the operating life

of the Subtitle C, RCRA-permitted facility would be equal to or less

than 1 mrem/year (10 Sv/year), if integrated over the

facility's operating life.

Again, the activity constraint and the water pathway

considerations can be placed in perspective by evaluating the

potential normal disposal of EAF emission control dust at a Subtitle

C, RCRA-permitted facility. If this dust includes a background

137Cs concentration of 1 pCi/g (0.037 Bq/g), and the facility

can treat 200 tons (180 metric tons) of dust per day, the total

quantity of 137Cs disposed of annually would be about 50 mCi

(1.85 GBq). Thus, over a facility operating period of about 20

years, the total quantity of 137Cs disposed of could equal the

1-Ci (37 GBq) incident-related material activity constraint.

5. Intruder Considerations

In the development of its licensing requirements for land

disposal of radioactive waste in 10 CFR Part 61, NRC considered

protection for individuals who might inadvertently intrude into the

disposal site, occupy the site, and contact the waste. In the

context of this position, this possibility has been considered

although the greater risk to the intruder would likely result from

the non-radiological hazardous constituents at the site.

In the intruder scenarios applied in the development of NRC's

LLW standards, 16 an inadvertent intruder was assumed to dig a

3-m (9.9-ft) deep foundation hole for construction of a house. The

top 2 m (6.6 ft) of the foundation were assumed to be trench cover

material and the bottom 1 m (3.28 ft) was assumed to be waste. Based

on the details of the scenarios, which included these and other

considerations, the intruder interacted with material whose

concentration had been reduced from the waste concentration by a

factor of 10. Presuming similar scenarios and assuming intrusion

occurs immediately after a post-closure care period of 30 years, the

intruder would be exposed to a 137Cs concentration of about 4 pCi/g

(0.15 Bq/g); that is, 77 pCi/g (2.84 Bq/g) reduced by the factor of

10 and an additional factor of 2 to account for radioactive decay).

Even for this worst-case situation in which all the incident-related

waste was presumed to have initial 137Cs concentrations of 77 pCi/g

(2.84 Bq/g), the projected intruder exposure would range from 0.8 to

3.8 mrem (8 to 38 Sv/year).17 As noted above, the

average concentrations over large volumes of incident-related

material would be expected to be far less than 77 pCi/g (2.84 Bq/g).

---------------------------------------------------------------------------

\16\ See NUREG-0782, Vol. 4, Draft Environmental Impact

Statement on 10 CFR Part 61, ``Licensing Requirements for Land

Disposal of Radioactive Waste,'' September 1981.

\17\ These estimates are based on the concentration to dose

conversion values in NUREG-1500, ``Working Draft Regulatory Guide on

Release Criteria for Decommissioning: NRC Staff's Draft for

Comment,'' August 1994. Appropriate adjustments of the tabulated

information were made to reflect the occupancy and shielding

assumptions made in NUREG-0782 (see Footnote 16).

---------------------------------------------------------------------------

6. Conclusions

These bounding analyses indicate that some significant volume of

137Cs-contaminated emission control dust and other incident-

related materials from an inadvertent melting of a sealed source can

be disposed of at a Subtitle C, RCRA-permitted

[[Page 13184]]

facility with negligible impacts to public and worker health and

safety and the environment. This method for disposal, if implemented

according to the limitations stipulated in this position, is very

unlikely to cause worst-case exposures that exceed 1 mrem (10

Sv) to any worker at the disposal facility or to any member

of the public in the vicinity of the facility. The design,

operations, and post-closure activities that take place at Subtitle

C, RCRA-permitted facilities will ensure that radiological impacts

from 137Cs will also be negligible in future timeframes. Proper

disposal of these materials would protect public health and safety,

and the environment to a greater degree than the alternative of

indefinitely storing these materials at a steel company facility.

The calculated public health and safety and environmental impacts of

disposition of specified incident-related materials at a Subtitle C,

RCRA-permitted facility can also be used to determine an optimum

course for disposal, if disposition alternatives exist.

BILLING CODE 7590-01-P

[[Page 13185]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.010

[[Page 13186]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.011

[[Page 13187]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.012

[[Page 13188]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.013

[[Page 13189]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.014

[[Page 13190]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.015

[[Page 13191]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.016

[[Page 13192]]

[GRAPHIC] [TIFF OMITTED] TN19MR97.017

BILLING CODE 7530-01-C

[[Page 13193]]

Analysis of and Response to Comments on Staff Technical Position

``Disposition of Cesium-137 Contaminated Emission Control Dust and

Other Incident-Related Material''

On January 22, 1996, the Nuclear Regulatory Commission published

a proposed technical position on the disposition of Cesium-137

(137Cs) contaminated emission control dust and other incident-

related materials in the Federal Register (61 FR 1608). Comments

were solicited and, in response, 22 comment letters were received.

These comment letters included: six from State nuclear safety, human

resources, environmental conservation, and health offices; five from

the steel industry (three from industry associations); four from

hazardous waste disposal facility operators; one from a mixed-waste

disposal facility operator; two from other industry associations;

two from environmental groups; one from a member of the public; and

one from a member of Congress. These letters raised a number of

issues ranging from policy and legal concerns to specific comments

on the conservatisms in the position's supporting radiological

assessments. The responses to these submitted comments have been

grouped into the following categories: (1) Position justification,

precedence, and relationship to ``below regulatory concern'' (BRC)

policy considerations and constraints; (2) regulatory approach

(i.e., rulemaking versus technical position) and the implementation

process; (3) legal considerations; (4) related health, safety, and

environmental concerns; (5) technical considerations; (6) other

issues; and (7) clarifications.

1. Justification, Precedence, and Relationship to BRC

a. Comment: The comments on the justification issue were

intertwined with several other issues. Basically, however, the

comments from the steel and other industries (associations), three

States, the Subtitle C, hazardous waste facility operators, and the

Congressman supported the disposal concept, proposed in the

position, as a necessary adjunct to a regulatory program that should

improve licensee control of the devices, whose inadvertent meltings

have caused the problem. They believe that the position is safe,

environmentally sound, and cost-effective, and a reasonable

alternative to disposal at the existing mixed-waste disposal

facility (available since April 1995 for disposal of the subject

waste). These commenters, plus those from the disposal facility

operators, expressed the view that there was a serious lack of

competition in the business of disposing of mixed waste, resulting

in unacceptably high disposal costs. Several of these commenters,

including one State, suggested that the disposal costs could affect

the financial viability of certain facilities.

Comments from two of the States, the environmental groups, the

member of the public, and the mixed-waste disposal facility operator

stated that the justification (or combined justification and

regulatory approach) for the position was weak, with most

emphasizing the conflict with the current policy on, and approach

to, mixed-waste disposal. One State and the mixed-waste disposal

facility operator noted that the time, effort, and resources

expended to effect mixed-waste disposal at the existing facility

will be undermined by the precedent being established in the

position. The disposal facility operator also believed that the

position relied on unsubstantiated economic assumptions and

assertions, which NRC had accepted at face value without any

independent investigation, and that the justification had changed

with position development from a public-health to a cost-effective

rationale. This commenter also stated the belief that the position

was not in the public's interest because of potential exposures to

transportation workers, members of the public, and Subtitle C

facility workers. One of the environmental group commenters stated

that saving a few cents per ton of steel may not be in the public's

best interests.

a. Response: Because the subject disposition option was being

proposed in the form of a ``permissive'' technical position (i.e.,

an option, likely requiring multiple approvals, that would be

initiated by a request from an NRC or Agreement State licensee on a

case-by-case basis) and not a rule, the broad policy justification,

stated in the Federal Register notice (61 FR 1609, column 1) was as

follows: ``NRC believes that disposal, under the provisions of the

position or other acceptable alternatives (emphasis added), is

preferable to allowing this mixed waste to remain indefinitely at

steel company sites.'' Another acceptable alternative referred to in

the Federal Register notice (61 FR 1610, column 3) is the mixed

waste disposal facility operated by Envirocare of Utah. As the

footnote indicated, this facility received authorization to accept

the subject waste at concentrations not exceeding 560 picocuries

(pCi)/gram (g) (20.7 becquerel (Bq)/g) during April 1995, after the

work on the technical position was initiated. With the availability

of this facility, the NRC staff believes its aforementioned public

health justification became enmeshed with cost considerations, as

described below.

Notwithstanding the availability of the mixed-waste disposal

facility option, which has been used by several steel facilities

with 137Cs-contaminated, incident-related material, other steel

companies did not consider this option cost-effective. Contrary to

the commenter's statement, NRC staff did contact the industry, as

well as the mixed-waste and Subtitle C disposal facility operators,

to comprehend the possible cost differentials of the disposal

alternatives. Although contractual privacy and market considerations

prevented exact determination, NRC staff concluded that the

differential costs between the mixed-waste and Subtitle C disposal

options could be significant. In fact, the comment letters from the

mixed-waste disposal facility operator and the Subtitle C facility

operators appear to confirm this assessment. But whatever the actual

cost differences may be for specific situations, the process, as

envisioned in the potential use of the position, would identify the

cost differentials, if any, in the environmental assessment that

would support any decision to implement the position's disposition

alternative (One State commenter stated that it should be made clear

that an environmental assessment, under the National Environmental

Policy Act, would be required for each disposal). The significance

of any cost differential could be judged by appropriate regulatory

authorities, in their selection of the most reasonable and proper

disposal alternative (e.g., whether saving a few cents per ton of

steel is in the public interest).

In its decision to pursue what, the Commission believes, is a

health-protective and environmentally sound disposition alternative,

the Commission also considered the origin of the radioactive source

melting problem (a problem being addressed under a separate NRC

program) and the significant efforts of the steel industry to detect

incoming radioactive material. In the Commission's view, these

factors provided further justification for its ongoing actions.

Thus, although the Commission is aware of the substantial efforts,

time, and resources expended by all parties involved in the

licensing of the mixed-waste disposal facility, the Commission's

primary focus is to achieve ultimate disposition of the incident-

related material. The Commission believes that the real or imagined

cost differentials, from lack of competition or other causes, may be

resolved through issuance of the position, and lead to a resolution

of the disposal problem. The Commission has coordinated its actions

with the U.S. Environmental Protection Agency (EPA) and believes it

has the support of EPA in the position, at this proposal stage.

The potential exposures to workers and members of the public are

addressed in the responses to comments 3.a. and 4.f.

b. Comment: Two State commenters, the mixed-waste disposal

facility operator, the environmental group commenters, and the

member of the public raised concerns about the precedent-setting

nature of the technical position. By establishing a ``default''

value for 137Cs in incident-related material, it was questioned

why a similar argument could not be made for 137Cs in soil, or

some other radionuclide in another medium. It was further pointed

out that the cumulative effect of similar actions would need to be

addressed. An environmental group commenter opposed the creation of

exemptions that could be used by others, specifically the Department

of Energy, as applicable or relevant and appropriate requirements,

in settings for which the drafters of the [position] did not intend

or anticipate. The member of the public claimed a possible

relationship to issues involving disposals from the U.S. Enrichment

Corporation.

Commenters from the steel and other industry associations

supported the position as a proper precedent, and suggested that

other circumstances could justify similar actions. It was pointed

out, for example, that although Basic Oxygen Furnaces (BOFs) also

process scrap and are subject to the same kinds of incidents as

Electric Arc Furnaces, BOF dust may be neither a listed hazardous

waste nor a characteristic hazardous waste. It was suggested that

the position be clarified regarding its applicability to the

potential

[[Page 13194]]

disposal of 137Cs-contaminated BOF material and incident-

related material that may not be classified as mixed waste. Another

industry commenter questioned whether the position would apply to a

steel producer who is not an NRC or Agreement State licensee. This

same commenter questioned what approach would be used for meltings

involving other radionuclides, and whether the position could not be

broadened to other industries that have large volumes of mixed

waste. In a broader sense, a few of these commenters applauded NRC

and EPA efforts to minimize dual regulation of mixed waste.

b. Response: The Commission strongly believes that broad-based

exemptions, or creation of specific positions outside of established

policies, should be implemented through the rulemaking process. In

fact, efforts to provide the technical analyses to support a broad

recycle rulemaking, that would include consideration of incident-

related material, are underway. However, under its specific

regulations, cited in the technical position, the Commission can,

and has, in case-by-case determinations, approved actions that it

believes are in the best interests of public health and safety and

protection of the environment. In the case of this ``permissive''

technical position, NRC is putting forward a disposition option,

whose implementation and approval can be considered by applicable

regulatory authorities and others. The advantages and disadvantages

of alternatives would be addressed in appropriate environmental

assessments that would accompany license amendment requests, and the

choice would require acceptance by various regulatory authorities

and others, and would be contingent on State laws and permit

conditions.

The Commission believes the precedent being suggested, in this

case, is reasonable and proper, based on the circumstances and the

justification, as described in 1.a. above. The disposition option,

however, applies only to disposals at Subtitle C facilities; only to

treated (stabilized) 137Cs-contaminated, incident-related

material (inclusive of material that may not be classified as mixed

waste) that constitutes the greatest part of the problem; and only

to companies, or their service contractors, that will treat the

incident-related material, under NRC or Agreement State license, to

meet the land disposal requirements that would apply if the material

contained hazardous constituents. This last provision was considered

necessary to avoid the difficult task of generically defining bounds

on the potential radiological exposures that could occur during

treatment or disposal, and could involve consideration of inhalation

and ingestion, as well as direct exposure pathways.

With regard to other possible situations for which this position

may be considered a precedent, such as the disposal of BOF material,

the Commission believes these situations should be judged on their

own merit. Any interactions among combined actions would require

consideration, as one of the State commenters pointed out. The staff

is also aware of EPA interests, identified in its proposed Hazardous

Waste Identification Rule, and has encouraged EPA efforts to

identify mixed wastes that may be regulated as low-level radioactive

waste (LLRW), outside of Resource Conservation and Recovery Act

(RCRA) regulations. The response to comment 2 is also pertinent to

the question of developing a broader technical position. The staff

has had no interactions with U.S. Enrichment Corporation issues that

affected development of this position.

c. Comment: Several commenters either requested clarification on

the relationship of this position to BRC policy or stated their

belief that the position contravenes public law.

c. Response: In 1992, in response to the Commission's

publication of a BRC policy statement in 1990, Congress, in Public

Law 102-486, Energy Policy Act of 1992, stated that the [BRC] policy

shall have no effect. The BRC policy basically stated the bases that

the Commission would apply to determine if broad practices should be

considered for exemption from regulatory control. The NRC staff does

not believe that the subject technical position is a BRC policy for

the following reasons: (1) The technical position is a

``permissive'' guidance statement, basically stating Commission

views on safe implementation of existing regulations on licensed

material disposal in 10 CFR Part 20; (2) the position specifically

``directs'' the disposal to a regulated disposal entity, and

includes approval, notification, and total activity provisions that,

the staff believes, are inconsistent with the concept of BRC; (3)

the position is narrow in scope (i.e., directed at specific

material, caused by specific circumstances); and (4) if implemented,

the actions under the position are consistent with other case-by-

case determinations made by the Commission.

2. Regulatory Approach and the Implementation Process

Comment: Although related to the BRC issue discussed above, a

State commenter questioned why, if the proposal is sound in

protecting public health and safety, the regulatory approach is a

technical position, as opposed to a rulemaking--the latter providing

a broader review process. Another State commenter believed NRC

should define the ``life expectancy'' of the guidelines in the

technical position. Industry comments generally supported the

technical position as the approach needed to address a real problem

in a timely manner, as opposed to a rulemaking that would be very

time-consuming. They believe the steel companies should not be put

in the middle of a political tug-of-war over appropriate

administrative procedures to follow, given that the position has

been made available for public scrutiny in a manner similar to a

proposed rule.

Response: As referred to in 1.b. above, NRC staff intends to re-

address the Subtitle C-disposal option, proposed in the technical

position, in conjunction with a broad recycle rulemaking. At that

time the need to broadly address disposal options will be revisited.

However, because this rulemaking is in an early development stage,

with finalization unlikely in the next couple of years, and because

of the desirability of properly disposing of specific incident-

related material in a timely manner, the Commission directed that

the staff should work with EPA to develop interim guidelines and

associated technical bases. This is the process that has been

followed to date. The guidelines proposed in the technical position

would be in effect until this rulemaking is finalized.

To address the concern of the State commenter regarding a

broader review process, the staff has not only worked with EPA, but

has made early versions of the position available directly to a

number of affected parties and States. The Commission's intentions

were openly discussed and the early versions of the position,

together with early exchanges of views, were placed in NRC's public

document room. The staff published the proposed technical position

in its entirety in the Federal Register to obtain the broader review

that the commenter suggests. Furthermore, contrary to interpretation

of one commenter, NRC is not asserting the adoption of the technical

position as a matter of Agreement State compatabilty. In fact,

recognizing the likely involvement of many parties, if the

position's alternative is implemented, the staff's intent was that

this wide review and approval could be helpful in gaining general

understanding and acceptance of the merits of the proposed

alternative. Case-by-case reviews and approvals of individual

applications to use the position's disposal approach will still be

necessary even with the final technical position in place.

3. Legal Considerations

a. Comment: In several comment letters from the States and a

Subtitle C disposal facility operator, and in staff discussions with

other Subtitle C disposal facility representatives, it was pointed

out that the legal applicability of the technical position's

disposal alternative, in specific States, could be determined by how

the incident-related material is defined. If the waste were defined

as LLRW, requiring disposal as specified in the Low-Level Waste

Policy Amendments Act of 1985, the disposal alternative described in

the position could be precluded, absent an appropriate change to

State law or regulations, or permit conditions. One State commenter

stated that, if the treated incident-related material is considered

contaminated ash, it would be subject to permit and manifesting

requirements.

Another State commenter pointed out that State LLRW regulations

require demonstration that design, operation, and closure of any

class of LLRW facility ensure protection against inadvertent

intrusion and provide for an institutional control period. There was

concern about States being open to lawsuits if the incident-related

material were considered LLRW and if the aforementioned provisions

were not addressed. The mixed-waste disposal facility operator

pointed out that Subtitle C facilities are not required to have

radiation training programs. Another State commenter questioned the

differences that would exist between the Subtitle C and mixed waste

disposal facility requirements and their rationale, in the context

of the position.

a. Response: In the ``Regulatory Position'' text in Section C,

the waste that could be

[[Page 13195]]

transferred to the Subtitle C disposal facility was described as

incident-related material, and was not referred to as low-level

radioactive waste. In developing the proposed position, this was not

a decision based on legal considerations, but the terminology

selected to best characterize the waste, in a technical position

whose principal purpose was to demonstrate, through a conservative

assessment, the minimal radiological significance of the proposed

disposal option. It was recognized, however, that State laws and

permit conditions would need to be satisfied, and that numerous

approvals may be required, including those of appropriate State

regulatory bodies and the disposal facility operator.

Among other provisions, implementation of the disposal option

proposed in the position: (1) Involves a licensee's request and

regulatory approvals on a case-by-case basis pursuant to 10 CFR

20.2002; (2) includes notification and disposal-site operator-

approval provisions; and (3) includes accounting of the single and

total incident-related material received at a Subtitle C disposal

site. As a result, the position does not allow a licensee to dispose

of the incident-related material as if it were not radioactive, a

concept that applies only to disposal of certain wastes defined in

NRC regulations at 10 CFR 20.2005(a). Instead, if the provisions of

the position are followed, including the specific provision for

disposal at a Subtitle C facility, the position provides a basis for

disposing of incident-related material at a site other than one

specifically licensed for disposal of low-level radioactive waste.

Furthermore, although not taking a position on what LLW disposal

requirements could be reasonably applied to the disposal of this

incident-related material at a Subtitle C hazardous waste disposal

facility, the staff did specifically address groundwater and

intruder considerations. Groundwater and intruder assessments were

provided to allow others to judge the significance of these

scenarios and the need for additional regulatory provisions

(including radiation protection training). NRC staff has concluded

that, with the constraints provided in the position, specific

regulatory actions (e.g., groundwater monitoring for \137\Cs,

intruder barriers, institutional controls beyond those applicable to

Subtitle C disposal facilities) directed at these scenarios are not

necessary.

The NRC staff has also concluded that the position's dose

criterion, and the conservative assessment of allowable \137\Cs

concentrations, obviates the need for radiation protection training

for the Subtitle C facility workers. In this regard, the staff would

point out that the material defined by the technical position would

not be considered radioactive, for transportation purposes, under

the U.S. Department of Transportation's (DOT's) regulations. In

fact, the concentration criteria in the position are a factor of

about 20 less than the value used by DOT to define radioactive

material.

b. Comment: Two State commenters pointed out that the position

does not address specific permitting provisions pertaining to dust

treatment to meet land disposal requirements for the dust's

hazardous constituents. One of these commenters stated that NRC

cannot assume sole jurisdiction for [hazardous] waste treatment, if

such treatment were conducted at the steel company sites.

b. Response: The commenter is correct. The position calls for

compliance with RCRA land disposal requirements. In the situations

being addressed, the NRC staff believes appropriate RCRA authorities

may approve various options for carrying out the treatment of the

incident-related material. Therefore, only a general statement of

compliance was included in the technical position. The staff

acknowledges and agrees with the comment regarding NRC's

jurisdiction over hazardous waste treatment, no matter where

conducted. This would be an issue for the State-permitting agencies

or EPA to decide. In essence, the presumption in the position is

that the Subtitle C disposal facility would be disposing of waste

that had been treated under applicable RCRA requirements.

4. Related Safety, Health, and Environmental Concerns

a. Comment: An environmental group, a State commenter, and the

member of the public suggested that the best approach to solve the

problem is a better accounting of the sources causing the incidents,

and more rigorous regulation appears warranted. The suggestion was

made that worker exposure at the foundries should be a principal NRC

concern. As indicated in the discussion in comment 1.a., the steel

industry commenters also strongly requested NRC action to improve

accountability.

a. Response: The Commission, in its directions to the staff on

October 18, 1994, approved several concurrent courses of action. One

of these has led to the development of the proposed position, while

another has led to an Agreement State-NRC Working Group that is

developing recommendations to address the accountability issue. The

Working Group has held several meetings and a workshop, and

recommendations were sent to the Commission in late 1996. The NRC

staff is in the process of evaluating the NRC/Agreement States

Working Group's recommendations for increased control over, and

accountability for, devices containing radioactive material. Once

the NRC staff completes its evaluation, it will submit an action

plan to the Commission outlining measures to improve control over,

and accountability for, devices. Thus, the Commission agrees with

the commenter's worker safety and ``front-end'' concerns but,

recognizing that incident-related material currently exists, and

future incidents may not be prevented with 100 percent confidence,

believes the ``back end'' of the problem also requires Commission

action.

b. Comment: A State and an environmental group commenter viewed

the policy, in its granting of a ``regulatory exemption'' for the

incident-related waste, as counterproductive to the desire to

improve detection capabilities at the steel facilities. Three

industry commenters, one who responded directly to the State view,

pointed out that the steel company facilities have installed state-

of-the-art radiation-detection capabilities at considerable expense,

not to meet any regulatory requirement, but to reduce the likelihood

of experiencing the consequences of inadvertent-melting events that

result in significant shutdown, cleanup, and disposal costs, as well

as the possibility of incident-related exposures to plant personnel.

Furthermore, these detection systems have been coupled with

comprehensive scrap inspection programs.

b. Response: Although the policy provisions may require NRC or

appropriate Agreement States to not require licensing of the

Subtitle C facility for the radioactive material, the main feature

of the policy is the NRC determination that the incident-related

material can be transferred, under existing regulations (10 CFR

20.2001 and 20.2002), from a licensed to an unlicensed entity. The

position not only provides a conservative NRC assessment of the

radiological impacts of the disposal alternative, but also evaluates

certain hypothetical situations to provide a frame of reference for

the calculated impacts. Contrary to the connotation, ``regulatory

exemption,'' used by the commenters, NRC staff does not consider the

proposed position to be an exemption action, but an assessment that

could allow case-by-case decisions on incident-related material

disposals under current regulations (also see response 1.c.).

The staff also believes that this policy has no impact on a

steel company's selection of ``source'' detection capabilities. The

costs associated with shutdown (downtime) and cleanup alone can

exceed millions of dollars, far in excess of the costs of effective

detection systems and programs.

c. Comment: The environmental group commenters and the mixed-

waste disposal facility operator suggested that the position could

lead the steel companies to continue operations after a melting for

the purpose of generating additional contaminated dust in sufficient

volume to meet the position's concentration criteria. A State

commenter stated that this issue should be addressed. The mixed-

waste disposal facility operator postulated other abuses (e.g., the

mixing of other regulated waste with [incident-related] material)

and asked whether prevention measures were being proposed.

c. Response: The staff believes that the cost disincentives

alone are sufficient to consider the former suggestion unreasonable.

For example, the dilution necessary at one of the facilities with

this material, such that all the contaminated material would comply

with the position's criteria, would be about a factor of 5. The

costs of disposing of this increased volume at a Subtitle C

facility, even with an optimistic estimate of disposal costs, could

reach millions of dollars. The staff would note that its development

of this position has been enmeshed with cost-effective

considerations because of the real or imagined excessive

differential costs of the disposal alternatives. Furthermore, based

on the operation of the steel facilities' emission control systems,

with their dust-collection systems, the staff can not conceive of a

scenario that would allow real time comprehension of the extent of

the contamination or total quantity of \137\Cs involved in an

incident.

[[Page 13196]]

With regard to the question of protective measures, the staff

believes the NRC, Agreement State(s), permitting agencies, or the

Subtitle C disposal facility operator could, if warranted, require

or strongly recommend testing requirements to address any concerns

on disposal of unauthorized radioactive material. The NRC staff

believes that a licensee's measurement and sampling program, as

approved by NRC or the Agreement State, will be sufficient to

preclude unauthorized radioactive material disposals.

d. Comment: An environmental group commenter stated that the

concentration criteria in the position appear to be inconsistent and

less strict than criteria imposed by EPA on mill tailings at 40 CFR

Part 192. The mixed-waste disposal facility commenter questioned the

position's comparisons with environmental 137Cs concentrations.

The member of the public claimed the proposal would exempt 10 times

the amount of material that would have been exempted under the BRC

policy.

d. Response: The staff presumes that reference is being made to

the 5 and 15

pCi/g or 135 and 405 Bq/g remedial action criterion for radium=226

(\226\ Ra) in soil. These are criteria that would apply to soil that

could be released for unrestricted use. The concentrations in the

position are those for material that would be disposed of at a

hazardous waste disposal facility. Because radium is about 2.5 times

more hazardous from a direct exposure standpoint than 137Cs,

the position's bounding 137Cs values for Subtitle C facility

disposal are only about 3 to 4 times a value that would be found

acceptable for unrestricted release. In fact, the typical incident-

related material at under 20 pCi/g (540 Bq/g) would be within the

criteria range cited and applicable to unrestricted release

situations. Note also that the position contains a total-quantity

criterion which is not a part of the 40 CFR Part 192 regulations.

The comparison referred to by the mixed-waste disposal facility

commenter was between ``much of the mixed waste'' that contains

concentrations below 20 pCi/g (540 Bq/g). This concentration was

being compared with actual environmentally measured concentrations

of 11 and

12 pCi/g (6300 Bq/g) and statistically-predicted concentrations (95

percent value of distribution) up to 19 pCi/g (513 Bq/g). The

reference in footnote 13 of the final technical position is the

source of these values.

The staff was not certain about the intended context of the

comment from the member of the public, but has presumed it is

related to other issues addressed in the response to this comment,

comment 1.a., 4.e., or 4.f..

e. Comment: The mixed-waste disposal facility operator, among

others, suggested that the position, if adopted, may have adverse

health, safety, and environmental consequences. One issue involved

the disposition of higher-activity material that would not be

covered by the position's criteria. The commenter cites an example

where the 137Cs concentration, if averaged over all the

incident-related material, could be 551 pCi/g (14,900 Bq/g)--[below

the acceptance criteria at the mixed waste facility]. If the

material with concentrations below the position's values is disposed

of under the position's provisions, the commenter asks what would be

the disposition of the higher concentration material and, if it

remains onsite, would this violate NRC's intent in promulgating the

position.

In a somewhat related comment, a State questioned whether

material delisted from hazardous material regulations, and meeting

the concentration values in the position, could be disposed of at a

Subtitle D facility.

e. Response: For incident-related material remaining after

``position-allowed-'' and economically feasible blending of

contaminated material, the staff is aware of only one disposition

option at this time (see 61 FR 1616, column 2). That option would

involve treatment and delisting of the material under hazardous

material regulations, and disposal of the material as LLW. In two

situations where incident-related material existed or currently

exists at steel facilities, about 90 percent of the activity was

contained in a few percent of the material volume. Given that, in

many cases, it may not be feasible to blend the 137Cs in this

small volume to concentrations acceptable at either the mixed waste

or the Subtitle C facility (under the provisions of the position),

treatment and delisting of this small volume may not be onerous. In

any event, the staff does not believe the uncertainty or current

feasibility of addressing a small percentage of the problem affects

the merits of the position, especially as it relates to the mixed-

waste or Subtitle C disposal alternatives.

In response to the State query, the position does not justify

disposal at a Subtitle D sanitary waste landfill because the

radiological assessment was based on a Subtitle C facility disposal.

Any such disposal, if justified, would have to address the

differences, if any, between facilities and their operations.

f. Comment: A series of comments from the mixed-waste disposal

facility operator questioned NRC's appreciation of the potential

effects of exposure to low levels of radiation. On the other hand,

most other commenters either considered the regulatory basis for the

position of 1 mrem (10 microsievert (Sv)) per year (yr) to

be reasonable or very conservative. Among several comments, one

commenter suggested a modest increase in the position's dose basis

from 1 mrem (10 Sv)/yr to 4 mrem

(40 Sv)/yr, corresponding to the value in EPA drinking

water standards.

f. Response: For a number of years, the Commission has used the

linear no-threshold hypothesis as providing a reasonable and prudent

basis to assess the radiological risk associated with its actions.

In essence, this hypothesis involves an extrapolation of the

statistically significant health effects that can be attributed to

high-level, short-duration exposures (e.g., the Japanese atomic bomb

survivors) to levels of exposure at or below what the earth's

population receives from background sources (e.g., cosmic radiation

and exposure to radiation emanating from naturally occurring

materials). Notwithstanding the scientific controversy regarding the

reality of these hypothetical risks, the Commission's radiation

protection standards are consistent with standards, recommended by

international and national advisory bodies, that reflect this

hypothesis.

In the case of the technical position, a dose rate of 1 mrem/yr

(one-hundredth of the public dose limit and about one three-

hundredth of the average exposure rate received year in and year out

by the population of the United States) was chosen as the regulatory

basis, because, in the staff's view, it was suitably conservative

and, from a practical standpoint, provided a disposition solution

for most of the incident-related material currently existing at

steel company sites. Footnote 5 of the final technical position

reflected this view.

With respect to the mixed waste disposal facility operator's

comments on the NRC staff's appreciation of the effects of low-level

radiation and the 1 mrem/yr (10 Sv/yr) regulatory basis,

the staff believes that the conservatisms in its selection of a dose

criterion, with appropriate regulatory margins, can be appropriate,

if the resulting position can lead to resolution of an outstanding

incident-related waste disposition problem. Although selection of 4

mrem (40 Sv)/yr could be justified, staff's view is that

selecting a drinking water standard for this position, which staff

believes does not present a drinking water issue, would create more

concern and confusion than the value selected, and its associated

basis.

5. Technical Considerations

a. Comment: A State commenter suggested that the position should

specify acceptable methods for averaging the waste within a

container.

a. Response: The staff recognizes that the incident-related

material in a particular container may not be homogeneous in terms

of 137Cs concentration. However, because the principal

radiological hazard being addressed is related to direct exposure,

complying with the concentration values, as determined on a

container average basis, is acceptable. The specifics of the

characterization program directed at defining treated-material

(137Cs concentrations) would be defined when approving the

licensee's request for transfer of the incident-related material.

The characteristics of the treated material, the decision to pursue

packaged or unpackaged disposal, the statistical confidence desired,

the regulatory margins provided in the position, and the views of

the approving parties would need to be considered. The response to

comment 7.c. could also be applicable in determining a

characterization program.

b. Comment: The mixed waste facility operator noted that if one

considered exposure to a plane source of 60 rem (0.6

Sv) per hour for 8 hours per day for over 4 weeks, the

result would be a total exposure exceeding EPA's maximum allowable

dose. An industry association commenter noted that the dose rate

limit applied to shipments of radioactive material is a factor 500

times higher than the value applied in the position to packaged

disposal.

[[Page 13197]]

b. Response: The staff does not believe this calculation is

pertinent. Although the staff is not certain what maximum allowable

dose is being referred to, the critical point in the calculation is

that it presumes continuous exposure at 1 meter (3 feet)

to a plane of material that is all at the maximum concentration

criterion. As a point of reference, exposure to ``normal'' dust

could be calculated to cause an exposure that would be a factor of

65 or lower, or presuming the possibility of greater exposure

periods associated with the greater volumes of material, equivalent

exposure would be reached over a period of about 5 years. The need

to consider the applicable exposure scenario on which a regulatory

position is based is brought out by the industry association

commenter. To make this point, the staff would note that under

similar assumptions, DOT's allowable exposure rate of 10 mrem (0.1

mSv) per hour at 1 meter (3 feet) could be translated

into a dose estimate of 1.6 rem (16 mSv).

c. Comment: An industrial association commenter suggested that

the 1-curie (Ci) or 3.7 x 10 \4\ MBecquerel (MBq) total activity

limit be modified to a per disposal cell basis (i.e., if the cell

were larger than 100,000 cubic meters (3.5 x 10 \6\ ft \3\)), on the

grounds that the proposed constraint may be too limiting if one

facility would accept the incident-related material from more than a

single event.

c. Response: Although this change could be justified, it has not

been accepted for the following reasons: (1) The procedural

difficulties for the NRC or Agreement State to require a particular

disposal constraint at an unlicensed facility, and (2) the belief

that individual incident disposals under the position's provisions

are, in most cases, unlikely to approach the quantity constraint

(one-tenth is expected to be more typical).

d. Comment: An industrial association commenter suggested that

the area/shape factors used by NRC were overly restrictive by a

factor of 2. d.

d. Response: NRC became aware of area/shape factor differences

between different codes. Staff has checked its calculations and does

not believe its estimates are in error.

e. Comment: A State commenter questioned whether a discrepancy

existed in NRC's source term assumption, in that dividing a 1-Ci

(3.7 x 10 \4\ MBq) source over 2000 tons (1814 metric tons) of

contaminated material would result in an average concentration of

551 pCi/g (1.49 x 10 \4\ Bq/g).

e. Response: The commenter's calculation is correct. However, in

actual events, a significant fraction of the activity is generally

contained in a small volume of incident-related material at high

concentrations. As discussed in the response to comment 4.e., the

disposition of this material will likely require treatment of its

hazardous properties, so that the material can be delisted and

disposed of at a licensed LLRW disposal facility. Although the

position's provisions do allow blending of contaminated material,

NRC staff recognized that providing the required reduction in

average concentration to meet the position's concentration criteria

would likely not be practical in all cases. Staff believed this was

reflected in the proposed position (e.g., see ``Introduction'' (61

FR 1609, column 3) and ``Discussion'' (61 FR 1610, columns 2 and

3)). This reality is why the activity that could be disposed of at

the Subtitle C facility, for the specific events that have taken

place to date, is unlikely to exceed 100 mCi (3.7 x 10 \3\ MBq).

f. Comment: A State commenter raised several questions about the

groundwater modeling and the input parameters.

f. Response: The commenter noted that these comments applied to

an earlier version of the position; however, a few still have

relevance to the proposed version. In the context of this position,

the staff was faced with the task of bounding a specific potential

radiological impact, that staff believed was relegated to a status

of insignificance by the position's defined concentration and

quantity criteria. Nevertheless, the approach taken in the position

was to perform simple bounding analyses and comparisons, so as to

provide a perspective on the specific hazard. For example, in

staff's view, a very conservative dose estimate was provided under

the hypothesis that an individual could and would drink trench

leachate. Contrary to the commenter's apparent view, staff considers

the very conservatively calculated 7-mrem (70-Sv) dose from

directly drinking trench leachate, with a bounding concentration of

radioactive material, to be a prima facie rationale for claiming

that EPA's drinking water standards would be met with significant

margin, not only at the ``tap,'' but at any point in the

groundwater.

6. Other Issues

Comment: A State commenter suggested that the position should

state whether NRC [would] allow import or export of incident-related

material for disposal.

Response: The position did not address the import/export issue.

To the extent that the position's assumptions remain valid, the

technical basis could be applied to export. However, any imports or

exports could involve decisions by responsible parties, beyond NRC,

including non-U.S. regulatory authorities. To the extent that

appropriate U.S. regulatory authorities agree, and determine that

they can legally support NRC's views that the treated incident-

related material is not LLRW, the material could be considered for

disposal under the provisions of the position, giving consideration

to its hazardous properties, if applicable. The staff does not

believe this issue needs to be addressed in the context of the

position itself.

7. Clarifications

a. Comment: A State commenter stated that the licensee

transferring the treated incident-related material should notify the

Agreement State Program or, in the case where an Agreement State

Program does not exist, the appropriate solid or hazardous waste

regulatory authority.

a. Response: The position's provisions are intended to ensure

such notifications. In the case of Agreement States, their approval

of the transfer is called for in the position's provisions, as is

written notification from the licensee at least 30 days before any

actual transfer. The position also calls for disposal facility

operator notification and acceptance, in writing. Thus, there are

two avenues through which the solid or hazardous waste regulatory

authorities would likely be apprised of actions to implement the

position. In non-Agreement States, NRC would be the initial, but

possibly not the only, radiological approving authority. In these

cases, State-permitting authorities may seek the advice and approval

of their respective State radiological or public health

organizations. NRC would work with these authorities and others to

determine if implementing the position's disposition alternative is

reasonable and prudent, and legally acceptable.

b. Comment: In the comments from one State, there appeared to be

some confusion on what entity would track the total quantity

constraint (i.e., 1 Ci or 3.7 x 10 \4\ MBq).

b. Response: Under the position's provisions, the total quantity

constraint would be tracked by NRC or the appropriate Agreement

State, although others could also track this inventory value.

c. Comment: A State commenter queried who would confirm that the

position's concentration constraints were being met. An

environmental group commenter suggested that accurate

characterization presents a considerable challenge.

c. Response: In the staff's view, NRC or the appropriate

Agreement State would have a significant incentive to provide some

independent verification of the concentration criteria. However, the

specifics of this verification would be addressed when approving the

licensee's request to make the transfer of incident-related material

under the provisions of the position. Other parties, including the

Subtitle C facility operator and the permitting agency, whose

approvals are required, could also dictate a specific confirmation

process. On this point, the staff would note the inclusion of

regulatory margins in the position that, staff believes, should be

considered in developing a reasonable confirmation program.

d. Comment: An industry association commenter requested

clarification regarding the shipment of pretreated incident-related

material to offsite licensed treatment facilities.

d. Response: Under the provisions of the position, NRC would

have no objection to incident-related material being transferred

offsite for permitted treatment by an NRC or Agreement State

licensed entity. The position only addresses the transfer of

incident-related material that has been properly treated, under a

Commission or Agreement State license, to a Subtitle C disposal

facility.

e. Comment: An industry group commenter suggested that the

position should provide allowance for licensed service contractors

to be brought in to supervise implementation operations. It was

further suggested that treatment should not be a prior condition to

transport.

e. Response: The position, and NRC regulations, allow the

possibility of service contractors operating under the contracting

entity's license. Treatment is only required before transport to an

unlicensed Subtitle C disposal facility. See the response to comment

7.d. above.

f. Comment: An industrial association commenter questioned the

accuracy of the

[[Page 13198]]

dose rates associated with the 55-gallon drum.

f. Response: The publication of the figures in the Federal

Register caused some blurring that has caused the commenter to

misread the indicated dose rate. Comparisons with the scale on the

ordinate indicate that the commenter's figure is high by a factor of

10.

Dated at Rockville, Maryland, this 13th day of March, 1997.

For the U.S. Nuclear Regulatory Commission

John W. N. Hickey,

Chief, Low-Level Waste and Decommissioning Projects Branch, Division of

Waste Management, Office of Nuclear Material Safety and Safeguards.

[FR Doc. 97-6884 Filed 3-18-97; 8:45 am]

BILLING CODE 7590-01-P