Proposed Generic Communication; Laboratory Testing of Nuclear- Grade Activated Charcoal (M97978)

NUCLEAR REGULATORY COMMISSION

Proposed Generic Communication; Laboratory Testing of Nuclear-

Grade Activated Charcoal (M97978)

AGENCY: Nuclear Regulatory Commission.

ACTION: Notice of opportunity for public comment.

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SUMMARY: The Nuclear Regulatory Commission (NRC) is proposing to issue

a generic letter concerning the laboratory testing of nuclear-grade

activated charcoal that is used in the safety-related air-cleaning

units of engineered safety feature ventilation systems of nuclear power

plants to reduce the potential onsite and offsite consequences of a

radiological accident by adsorbing iodine. The purpose of the proposed

generic letter is to: (1) Alert addressees that the NRC has determined

that testing nuclear-grade activated charcoal to standards other than

American Society for Testing and Materials (ASTM) D3803-1989,

``Standard Test Method for Nuclear-Grade Activated Carbon,'' does not

provide assurance for complying with their current licensing basis as

it relates to the dose limits of General Design Criterion (GDC) 19 of

Appendix A to 10 CFR Part 50 and Subpart A of 10 CFR Part 100, and that

ASTM D3803-1989 should be used for both new and used charcoal because

it allows for accurately monitoring the degradation of the charcoal

over time; (2) request that addressees determine whether their

technical specifications (TS) reference ASTM D3803-1989 for charcoal

filter laboratory testing and if not, either amend their TS to

reference ASTM D3803-1989 or propose an alternative test protocol and

provide the requested information; (3) alert addressees of NRC intent

to exercise enforcement discretion under certain conditions; and (4)

require that addressees submit written responses to this generic

letter.

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The NRC is seeking comment from interested parties regarding both the

technical and regulatory aspects of the proposed generic letter

presented under the Supplementary Information heading.

The proposed generic letter has been endorsed by the Committee to

Review Generic Requirements (CRGR). Relevant information that was sent

to the CRGR will be placed in the NRC Public Document Room. The NRC

will consider comments received from interested parties in the final

evaluation of the proposed generic letter. The NRC's final evaluation

will include a review of the technical position and, as appropriate, an

analysis of the value/impact on licensees. Should this generic letter

be issued by the NRC, it will become available for public inspection in

the NRC Public Document Room.

DATES: Comment period expires March 27, 1998. Comments submitted after

this date will be considered if it is practical to do so, but assurance

of consideration cannot be given except for comments received on or

before this date.

ADDRESSES: Submit written comments to Chief, Rules and Directives

Branch, Division of Administrative Services, U.S. Nuclear Regulatory

Commission, Mail Stop T6-D69, Washington, DC 20555-0001. Written

comments may also be delivered to 11545 Rockville Pike, Rockville,

Maryland, between 7:45 a.m. to 4:15 p.m., Federal workdays. Copies of

written comments received may be examined at the NRC Public Document

Room, 2120 L Street, N.W. (Lower Level), Washington, D.C.

FOR FURTHER INFORMATION CONTACT: John P. Segala, (301) 415-1858.

SUPPLEMENTARY INFORMATION:

NRC Generic Letter 97-XX: Laboratory Testing of Nuclear-Grade

Activated Charcoal

Addressees

All holders of operating licenses for nuclear power reactors,

except those who have permanently ceased operations and have certified

that fuel has been permanently removed from the reactor vessel.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this

generic letter to:

(1) Alert addressees that the NRC has determined that testing

nuclear-grade activated charcoal to standards other than American

Society for Testing and Materials (ASTM) D3803-1989, ``Standard Test

Method for Nuclear-Grade Activated Carbon,'' does not provide assurance

for complying with their current licensing basis as it relates to the

dose limits of General Design Criterion (GDC) 19 of Appendix A to 10

CFR Part 50 and Subpart A of 10 CFR Part 100. In addition, the staff

has determined that ASTM D3803-1989 should be used for both new and

used charcoal because it allows for accurately monitoring the

degradation of the charcoal over time.

(2) Request that all addressees determine whether their technical

specifications (TS) reference ASTM D3803-1989 for charcoal filter

laboratory testing. Addressees whose TS do not reference ASTM D3803-

1989 should either amend their TS to reference ASTM D3803-1989 or

propose an alternative test protocol and provide the information

discussed in the requested actions.

(3) Alert addressees of the staff's intent to exercise enforcement

discretion under certain conditions.

(4) Require that all addressees send the NRC written responses to

this generic letter, relating to implementation of the requested

actions.

Background

Safety-related air-cleaning units used in the engineered safety

feature (ESF) ventilation systems of nuclear power plants reduce the

potential onsite and offsite consequences of a radiological accident by

adsorbing radioiodine. To ensure that the charcoal filters used in

these systems will perform in a manner that is consistent with the

licensing basis of a facility, most licensees have requirements in

their facility TS to periodically test (in a laboratory) samples of

charcoal taken from the air-cleaning units.

The NRC's and the nuclear industry's understandings of the

appropriate laboratory tests for nuclear-grade charcoal have evolved

over the years since the issuance of Regulatory Guide (RG) 1.52,

``Design, Testing, and Maintenance Criteria for Postaccident

Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and

Adsorption Units of Light-Water-Cooled Nuclear Power Plants,'' which is

referenced in many plant TS. It was initially assumed that high-

temperature/high-relative humidity (RH) conditions were the most

severe. Later, with more testing experience, it became clear that the

most conservative test is at low temperature/high humidity. The use of

outdated test protocols or inappropriate test conditions can lead to an

overestimation of the charcoal's ability to adsorb radioiodine

following an accident.

Problems associated with the performance of the laboratory test of

charcoal under inappropriate test conditions were discussed in

Attachment 1 of Information Notice (IN) 86-76. Attachment 1, ``Summary

of Control Room Habitability Reviews,'' noted that charcoal was being

tested at much higher temperatures than any expected during the course

of an accident, and that the performance of the laboratory test at that

temperature can result in erroneously high efficiency measurements.

In 1982, the American Society of Mechanical Engineers (ASME)

Committee on Nuclear Air and Gas Treatment (CONAGT) conducted an inter-

laboratory comparison test using ASTM D3803-1979 and found that seven

U.S. laboratories and eight foreign laboratories obtained vastly

different results when testing samples of the same charcoal. After

efforts to resolve the differences failed, the NRC contracted with EG&G

at Idaho National Engineering Laboratory (INEL) to assess the problem.

As a result of this assessment, the NRC issued IN 87-32. Through IN 87-

32, the NRC informed licensees of deficiencies in the testing of

nuclear-grade charcoal, specifically noting serious problems with the

capabilities of the testing laboratories and with the testing standard

(ASTM D3803-1979). The NRC contractor detailed the specific problems in

its technical evaluation report, EGG-CS-7653, ``Final Technical

Evaluation Report for the NRC/INEL Activated Carbon Testing Program.''

Specifically, EG&G reported that ASTM D3803-1979 had unacceptable test

parameter tolerances and instrument calibration requirements, and that

ASTM D3803-1979 was nonconservative in not requiring humidity pre-

equilibration of used charcoal. The information notice indicated that

the protocol developed by EG&G could be utilized for performing the

laboratory test until the D-28 committee responsible for ASTM D3803

revised the standard. The committee completed the revision and issued

it in December 1989. The problems associated with the testing

laboratories were resolved after the number of U.S. firms performing

such tests dropped from seven to the current two.

On April 29, 1993, representatives from ASME and CONAGT met with

the NRC staff to express their concerns about laboratory testing of

charcoal. CONAGT discussed the variation in laboratory test results

obtained (methyl iodide penetration) when temperature, RH, face

velocity, bed depth, test protocol, and impregnate were varied. CONAGT

stated that the 1989 version of

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ASTM D3803 is the only acceptable test method for TS applications and

compared the results of laboratory tests performed using the 1986

version of ASTM D3803 (which is the 1979 version with editorial

changes) to results using the 1989 version. The results from the 1986

protocol showed significantly higher iodine-removal capabilities than

the results from the 1989 version.

In addition, CONAGT indicated that testing charcoal at temperatures

greater than 30 deg.C [86 deg.F] almost always results in the

charcoal meeting the TS acceptance criteria, even when the charcoal is

deficient. To support this premise, CONAGT presented the results of

laboratory tests conducted at temperatures of 30 deg.C [86 deg.F], 80

deg.C [176 deg.F], and 130 deg.C [266 deg.F]. The data show

significant increases in iodine-removal capabilities as the test

temperature increases. CONAGT indicated that all systems located

outside of containment should be tested at 30 deg.C [86 deg.F], which

is more representative of the limiting accident conditions. Tests

conducted at 80 deg.C [176 deg.F] or 130 deg.C [266 deg.F] are

inappropriate because tests at these temperatures result in the

regeneration of the charcoal. At elevated temperatures, the charcoal

contains less moisture than at 25 deg.C [77 deg.F] and 30 deg.C [86

deg.F] which results in the charcoal having more surface area available

for adsorption of iodine. Therefore, testing at the elevated

temperatures results in an overestimation of the actual iodine-removal

capability of the charcoal, and testing at 25 deg.C [77 deg.F] or 30

deg.C [86 deg.F] gives results that represent a more realistic

assessment of the capability of the charcoal. CONAGT concluded its

presentation by stating that the major problems associated with the

laboratory test of charcoal are the designation of the test protocol

and the TS that designate the test to be performed.

On November 6, 1996, the staff visited the two remaining

laboratories that test nuclear-grade activated charcoal, NCS

Corporation and NUCON International, Inc. Both laboratories have

resolved the poor reproducibility problem identified in the EG&G report

by performing all tests with calibrated equipment that is capable of

maintaining the tight tolerances of the test parameters as specified in

ASTM D3803-1989. Tight tolerances are very important when tests are

performed at high RH, because slight variations in RH result in

unacceptably large differences in the tested efficiency of the

charcoal.

Discussion

Although some licensees have changed their TS to reference the

latest testing standard (ASTM D3803-1989), many still use outdated

standards and/or test conditions that may overestimate the capability

of the charcoal in their ESF systems. As a result, the ability of the

charcoal filters in these systems to perform in a manner consistent

with the licensing basis for the facility may be in question.

The licensees of three plants (V.C. Summer, Davis-Besse and Oconee)

determined that the tests they performed were not in compliance with

their TS and submitted emergency TS amendments (see Enclosure 1 for

details). As a result of the emergency TS changes, the staff has

performed an internal survey of the TS of operating plants to determine

whether other plants have the potential for similar compliance

problems. The survey indicated that at least one-third of operating

reactor licensees may be out of compliance with their TS because,

although the plant TS reference RG 1.52 or American National Standards

Institute (ANSI) N509-1976, ``Nuclear Power Plant Air-Cleaning Units

and Components,'' the licensees may have used later versions of the

standards for the laboratory tests of their nuclear-grade charcoal. On

the basis of this survey, the staff established the following four

groups of plants:

(1) Plants in compliance with their TS that test in accordance with

ASTM D3803-1989.

(2) Plants in compliance with their TS that test in accordance with

a test protocol other than ASTM D3803-1989.

(3) Plants not in compliance with their TS that test in accordance

with ASTM D3803-1989.

(4) Plants not in compliance with their TS that test in accordance

with a test protocol other than ASTM D3803-1989.

Licensees in Group 1 have TS that require charcoal to be tested in

accordance with ASTM D3803-1989, which adequately demonstrates the

capability of the charcoal. As discussed in Enclosure 1, the staff

considers ASTM D3803-1989 to be the most accurate and most realistic

protocol for testing charcoal in ESF ventilation systems because it

offers the greatest assurance of accurately and consistently

determining the capability of the charcoal. For example, it requires

the test to be performed at a constant low temperature of 30 deg.C

[86 deg.F]; it provides for smaller tolerances in temperature,

humidity, and air flow; and it has a humidity pre-equilibration.

Licensees in Group 2 have TS that require charcoal to be tested in

accordance with test standards other than ASTM D3803-1989. On the basis

of available laboratory test results for more than 50 charcoal samples,

there were significant differences in filter efficiencies for about 15

to 20-percent of the tested samples when comparing the test results

from ASTM D3803-1979 and ASTM D3803-1989. When the charcoal samples

were tested in accordance with ASTM D3803-1979, they always appeared to

have very high efficiencies. However, when the same charcoal samples

were tested in accordance with ASTM D3803-1989, significant reduction

in efficiency was noted. Depending on the system arrangement, this

reduction in filter efficiency can result in calculated doses to the

control room operators exceeding the GDC 19 limits by as much as a

factor of 1.5 to 2. For pressurized-water reactors (PWRs) with

secondary containments and for all boiling-water reactors (BWRs), this

reduction in filter efficiency can result in offsite doses from a

filtered pathway increasing by as much as a factor of 10 to 15. As a

result, the testing of nuclear-grade activated charcoal to standards

other than ASTM D3803-1989 does not provide assurance for complying

with the plant's licensing basis as it relates to the dose limits of

GDC 19 and Part 100.

In addition, the staff has determined that ASTM D3803-1989 should

be used for both new and used charcoal because it allows for accurately

monitoring the degradation of the charcoal over time. The original

rationale for testing used and new charcoal differently was the belief

that a long equilibration period would regenerate the used charcoal by

removing contaminants adsorbed by the charcoal during normal plant use.

However, an EG&G technical evaluation report, described in Enclosure 1,

demonstrated that this is not true. As a result, ASTM D3803-1989

specifies testing both used and new charcoal in the same manner.

Currently, before shipping, suppliers test most new charcoal with

the ASTM D3803-1989 protocol at 30 deg.C [86 deg.F] and 95-percent RH

in addition to the test protocol and test conditions the addressee

records on the purchase order. The results from the new charcoal tested

via ASTM D3803-1989 present a solid baseline for the initial capability

of the charcoal. Using ASTM D3803-1989 to test used charcoal is a very

accurate and reproducible method for determining the capability of the

charcoal. By comparing the results of the used charcoal tests with the

new charcoal test baseline, the addressee can be certain of the

charcoal's level of degradation.

Analyses of design-basis accidents assume a particular engineered

safety features (ESF) charcoal filter adsorption

[[Page 9584]]

efficiency when calculating offsite and control room operator doses.

Licensees then test charcoal filter samples to determine whether the

filter adsorber efficiency is greater than that assumed in the design-

basis accident analysis. The laboratory test acceptance criteria

contain a safety factor to ensure that the efficiency assumed in the

accident analysis is still valid at the end of the operating cycle.

Because ASTM D3803-1989 is a more accurate and demanding test than

older tests, addressees that upgrade their TS to this new protocol will

be able to use a safety factor as low as 2 for determining the

acceptance criteria for charcoal filter efficiency. This safety factor

can be used for systems with or without humidity control because the

lack of humidity control is already accounted for in the test

conditions (systems without humidity control test at 95-percent RH and

systems with humidity control can test at 70-percent RH). The staff has

previously approved reductions in the safety factor for plants adopting

the ASTM D3803-1989 standard on a case-by-case basis. (The staff plans

to make conforming changes to RG 1.52.)

The licensees that received emergency TS changes were in Groups 3

and 4. Licensees in Groups 3 and 4 have TS that require charcoal to be

tested in accordance with RG 1.52 or ANSI N509-1976, and are not in

compliance with their TS because the specified test protocol can not be

successfully completed as discussed in Enclosure 1. These licensees are

either (1) testing in accordance with the desired ASTM D3803-1989

(Group 3) or (2) using earlier revisions of ASTM D3803 or an older

standard which they believe are acceptable (Group 4). The staff does

not have confidence that the results from RG 1.52 or ANSI N509-1976

meet the intent of the TS which is to ensure that the doses are within

the required limits. Therefore, licensees in these groups have not

adequately demonstrated compliance with their licensing basis as it

relates to the dose limits of GDC 19 and Part 100.

The staff believes that (1) conflicting guidance, (2) complex and

ambiguous standards, and (3) licensee belief that using later versions

of the standard would satisfy their TS requirements, contributed to

confusion regarding charcoal testing. These factors may explain why

licensees did not adopt ASTM D3803-1989 (See Enclosure, for further

discussion). In addition, based on the available laboratory test

results, the staff believes that most charcoal in use is not degraded

to an extent that would adversely affect control room habitability or

public health and safety. This confidence in charcoal performance and

given the low probability of a design basis accident, justify the time

frames for the resolution of this matter. Therefore, the staff intends

to exercise enforcement discretion, consistent with Section VII.B.6 of

the Enforcement Policy, for all addressees in Groups 3 and 4, provided:

Within 60 days of the date of this generic letter, either

charcoal samples are tested in accordance with ASTM D3803-1989 and the

results meet the current TS acceptance criteria or all of the charcoal

is replaced with new charcoal that has been tested in accordance with

ASTM D3803-1989;

Acceptable charcoal sample test results discussed in the

first condition are submitted to the NRC within 60 days of the date of

this generic letter;

A TS amendment request is submitted to the NRC within 60

days of the date of this letter; and

The charcoal samples continue to be tested in accordance

with ASTM D3803-1989 until the TS amendment is approved by the NRC.

In cases in which the charcoal samples have been previously tested

in accordance with ASTM D3803-1989 for the last scheduled laboratory

test and the results met the current TS acceptance criteria (Group 3),

the results can be used to satisfy the first condition above.

Licensees in Group 2 have been complying with their TS by testing

their charcoal in accordance with their TS. Therefore, enforcement

discretion is not required.

Requested Actions

Addressees are requested to take the following actions:

1. If your current TS require the laboratory testing of charcoal

samples for each ESF ventilation system to be conducted in accordance

with ASTM D3803-1989, then no TS amendment is required.

2. If your current TS do not require the laboratory testing of

charcoal samples to be conducted in accordance with ASTM D3803-1989,

then:

(i) Your charcoal samples should be tested in accordance with ASTM

D3803-1989 and the results should be submitted to the NRC within 60

days of the date of this generic letter. If your charcoal samples were

already tested in accordance with ASTM D3803-1989 for the last

scheduled laboratory test and the results met the current TS acceptance

criteria, then the results should be submitted to the NRC within 60

days of the date of this generic letter. In either case, the charcoal

samples should continue to be tested in accordance with ASTM D3803-1989

until the TS amendment is approved by the NRC, and

(ii) Your TS should be amended to require the laboratory testing of

charcoal samples to be conducted in accordance with:

(a) ASTM D3803-1989, or

(b) An alternate test protocol should be proposed for the

laboratory testing of charcoal and the following information should be

submitted for staff review to determine the acceptability of the

alternate protocol:

1. Summary of the test method

2. Precision of the method

3. Description of the test apparatus along with tolerances

4. Parameter specifications

5. Material requirements

6. Hazards

7. Preparation of the apparatus before initiation of the test

8. Calibration requirements of the test equipment

9. Test procedure

10. Manner of calculating penetration and error

11. Repeatability and reproducibility of the results for 1-percent and

10-percent penetration and the penetration at a 95-percent confidence

interval for charcoal tested at 70-percent RH and at 95-percent RH

12. Bias associated with the method

13. Results from an independent laboratory which demonstrate that the

alternate test protocol gets results that are consistent with, or more

conservative than, that associated with ASTM D3803-1989

The demonstration identified in Item 13 above should be based upon

a series of tests comparing the alternate test protocol and ASTM D3803-

1989, and it should apply to both new and used charcoal tested at 70-

percent RH and at 95-percent RH. The independent laboratory should be

able to demonstrate that the alternate protocol is at least as

conservative as ASTM D3803-1989, and should be able to perform the ASTM

D3803-1989 test and achieve repeatable and reproducible results. The

laboratory should not be engaged in the measurement of iodine

penetration of charcoal as a business either for TS compliance purposes

or for the sale and/or production of activated charcoal for nuclear

power plant applications.

Requested Information

Within 60 days of the date of this generic letter, addressees are

requested to provide to the NRC the following information:

1. Identify the current TS requirements for the laboratory testing

[[Page 9585]]

of charcoal samples for each ESF ventilation system including the

specific test protocol, temperature, RH, and penetration at which the

TS require the test to be performed. If your current TS specifically

require testing in accordance with the ASTM D3803-1989 protocol, and

you have been testing in accordance with this standard, then no

additional information is required.

2. If you choose to adopt the ASTM D3803-1989 protocol, then submit

a TS amendment request to require testing to this protocol. The request

should contain the test temperature, RH, and penetration at which the

proposed TS will require the test to be performed and the basis for

these values. If the system has a face velocity greater than 10 percent

of 0.203 m/s [40 ft/min], then the revised TS should specify the face

velocity. Also, indicate when the next laboratory test is scheduled to

be performed. (Enclosure 2 is a sample TS that the NRC considers

acceptable.)

3. If you are proposing an alternate test protocol, then address

the attributes discussed in Section 2(ii) of the Requested Actions and

submit a TS amendment request to require testing to this alternate

protocol. The request should contain the test temperature, RH, and

penetration at which the proposed TS will require the test to be

performed and the basis for these values. If the system has a face

velocity greater than 10 percent of 0.203 m/s [40 ft/min], then the

revised TS should specify the face velocity. Also, indicate when the

next laboratory test is scheduled to be performed.

Required Response

Within 30 days of the date of this generic letter, addressees are

required to submit a written response indicating: (1) Whether the

requested actions will be completed, (2) whether the requested

information will be submitted and (3) whether the requested information

will be submitted within the requested time period. Addressees who

choose not to complete the requested actions, or choose not to submit

the requested information, or are unable to satisfy the requested

completion date, must describe in their response any alternative course

of action that is proposed to be taken, including the basis for

establishing the acceptability of the proposed alternative course of

action and the basis for continued operability of affected systems and

components as applicable.

Address the required written response to the U.S. Nuclear

Regulatory Commission, ATTN: Document Control Desk, Washington, D.C.

20555-0001, under oath or affirmation, under the provisions of Section

182a, Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f). In

addition, send a copy to the appropriate regional administrator.

Backfit Discussion

Appendix A to 10 CFR Part 50, General Design Criteria (GDC) for

Nuclear Power Plants, and the plant safety analyses require and/or

commit that licensees design and test safety-related structures,

systems and components to offer adequate assurance that they can

perform their safety functions. Specifically, GDC 19 of Appendix A to

10 CFR Part 50 specifies dose limits to ensure that control room

operators are provided with adequate radiation protection under

accident conditions. Following the accident at Three Mile Island (TMI),

TMI Action Plan Item III.D.3.4, ``Control Room Habitability

Requirements,'' as specified in NUREG-0737, ``Clarification of TMI

Action Plan Requirements,'' required all licensees to perform

evaluations and identify appropriate modifications to ensure that

control room operators are adequately protected from the release of

radioactive gases and that the nuclear power plant can be safely

operated or shut down under design-basis accident conditions (GDC 19).

When modifications were proposed by licensees, the NRC issued Orders

confirming licensee commitments. As a result, all licensees are

required to meet the dose limits of GDC 19. In addition, Subpart A of

10 CFR Part 100 specifies reference dose values which can be used in

the evaluation of the suitability of proposed sites for nuclear power

plants with respect to potential reactor accidents that could result in

the release of significant quantities of radioactive fission products.

The expectation is that the site location and the engineered safety

features included as safeguards against the hazardous consequences of

an accident, should one occur, should ensure a low risk of public

exposure. In this regard, licensees commit to dose limits that can be

used as the basis for assessing the performance of safety-related

structures, systems and components. Accordingly, licensees are required

to test the nuclear-grade activated charcoal of their engineered safety

feature ventilation systems in accordance with a suitable testing

standard to ensure that the charcoal filters are capable of performing

their required safety function and that the licensing bases of their

respective facilities regarding onsite and offsite dose consequences

continue to be satisfied.

The actions requested in this generic letter are considered

compliance backfits under the provisions of 10 CFR 50.109. If some

licensees test their charcoal in accordance with their TS which

reference an outdated test standard, the staff does not have confidence

that the results of those tests will demonstrate compliance with the

plant's licensing basis as it relates to the dose requirements of GDC

19 and Part 100, including commitment to the resolution of TMI Action

Plan Item III.D.3.4. Therefore, the staff has endorsed the testing

standard ASTM D3803-1989 for referencing in plant TS. In accordance

with the provisions of 10 CFR 50.109(a)(4)(i), regarding compliance

backfits, a full backfit analysis was not performed. However, an

evaluation was performed in accordance with NRC procedures, including a

statement of the objectives of and reasons for the requested actions

and the basis for invoking the compliance exception and is reflected in

this backfit discussion.

Federal Register Notification

(To be completed after the public comment period.)

Paperwork Reduction Act Statement

This Generic Letter contains information collections that are

subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et

seq.). These information collections were approved by the Office of

Management and Budget, approval number 3150-0011, which expires

September 30, 2000.

The public reporting burden for this mandatory information

collection is estimated to average 40 hours per response, including the

time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing

the information collection. The U.S. Nuclear Regulatory Commission is

seeking public comment on the potential impact of the information

collections contained in the generic letter and on the following

issues:

1. Is the proposed information collection necessary for the proper

performance of the functions of the NRC, including whether the

information will have practical utility?

2. Is the estimate of burden accurate?

3. Is there a way to enhance the quality, utility, and clarity of

the information to be collected?

4. How can the burden of the information collection be minimized,

including the use of automated collection techniques?

[[Page 9586]]

Send comments on any aspect of this information collection,

including suggestions for reducing the burden, to the Information and

Records Management Branch (T-6 F33), U.S. Nuclear Regulatory

Commission, Washington, DC 20555-0001, or by Internet electronic mail

at [email protected]; and to the Desk Officer, Office of Information and

Regulatory Affairs, NEOB-10202, (3150-0011), Office of Management and

Budget, Washington, DC 20503.

Public Protection Notification

If an information collection does not display a currently valid OMB

control number, the NRC may not conduct or sponsor, and a person is not

required to respond to, the information collection.

Enclosures:

(1) Background Information on the Laboratory Testing of Nuclear-

Grade Activated Charcoal.

(2) Sample Technical Specifications.

Enclosure 1

Background Information on the Laboratory Testing of Nuclear-Grade

Activated Charcoal

Charcoal Testing Requirements

Analyses of design-basis accidents assume a particular engineered

safety features (ESF) charcoal filter adsorption efficiency when

calculating offsite and control room operator doses. Licensees then

test charcoal filter samples to determine whether the filter adsorber

efficiency is greater than that assumed in the design-basis accident

analysis. The laboratory test acceptance criteria contain a safety

factor to ensure that the efficiency assumed in the accident analysis

is still valid at the end of the operating cycle.

Guidance on the frequency of, and the test method for, the

laboratory testing of charcoal appears in various documents, including

all revisions of Regulatory Guide (RG) 1.52, ``Design, Testing, and

Maintenance Criteria for Postaccident Engineered-Safety-Feature

Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-

Water-Cooled Nuclear Power Plants,'' and other NRC documents on plant

technical specifications (TS). Guidance on the laboratory test protocol

appears in such standards as American National Standards Institute

(ANSI) N509, ``Nuclear Power Plant Air-Cleaning Units and Components;''

ANSI N510, ``Testing of Nuclear Air-Cleaning Systems;'' Military

Specification RDT M 16-1T, ``Gas Phase Adsorbents for Trapping

Radioactive Iodine and Iodine Components;'' and American Society for

Testing and Materials (ASTM) Standard D3803, ``Standard Test Method for

Nuclear-Grade Activated Carbon.''

All of the standards describe a pre-equilibration period, a

challenge period, and an elution period. During the pre-equilibration

(pre-sweep) period, the charcoal is exposed to a flow of air controlled

at the test temperature and relative humidity (RH) before the challenge

gas is fed through the charcoal. The pre-equilibration period ensures

that the charcoal has stabilized at the specified test temperature and

RH for a period of time, which results in the charcoal adsorbing all

available moisture before the charcoal is challenged with methyl

iodide. During the challenge period, air at the test temperature and RH

with radio-labeled methyl iodide is injected through the charcoal beds

to challenge the capability of the charcoal. During the elution (post-

sweep) period, air at the test temperature and RH is passed through the

charcoal beds to evaluate the ability of the charcoal to hold the

methyl iodide once it is captured.

The ASTM D3803-1989 standard has two additional testing periods

that are not required by other standards: the stabilization period and

the equilibration period. During the stabilization period, air at the

test temperature is passed through the charcoal beds to bring the

system up to the operating temperature before the start of pre-

equilibration. During the equilibration period, air at the test

temperature and RH is passed through the charcoal beds to ensure the

charcoal adsorbs all the available moisture before the feed period.

During this period, the system is more closely monitored than in the

pre-equilibration period to ensure that all parameters are maintained

within their limits.

Depending upon the plant's TS, typical test temperatures are

usually one of the following: 25 deg.C [77 deg.F], 30 deg.C [86 deg.F],

80 deg.C [176 deg.F], or 130 deg.C [266 deg.F]. In addition, the TS

usually require that the test be conducted at 70-percent RH if the ESF

system controls the RH to 70-percent or less, or at 95-percent if the

RH is not controlled to 70-percent.

The standard technical specifications (STS) and many plant-specific

TS specify Regulatory Position C.6.a of RG 1.52, Revision 2, as the

requirement for the laboratory testing of the charcoal. Regulatory

Position C.6.a refers to Table 2 of RG 1.52. Table 2 references Test

5.b of Table 5-1 of ANSI N509-1976, ``Nuclear Power Plant Air-Cleaning

Units and Components.'' Test 5.b references the test method from

paragraph 4.5.3 of Military Specification RDT M 16-1T, ``Gas Phase

Adsorbents for Trapping Radioactive Iodine and Iodine Components''

(date not indicated), but specifies that the test is to be conducted at

80 deg.C [176 deg.F] and 95-percent RH with preloading and postloading

sweep at 25 deg.C [77 deg.F]. This test is referred to as the ``25-80-

25 test.'' The essential elements of this test are as follows:

70-percent or 95-percent RH.

5-hour pre-equilibration (pre-sweep) time, with air at

25 deg.C [77 deg.F] and plant-specific RH.

2-hour challenge, with gas at 80 deg.C [176 deg.F] and

plant-specific RH.

A 2-hour elution (post-sweep) time, with air at 25 deg.C

[77 deg.F] and plant-specific RH.

The latest acceptable methodology for the laboratory testing of the

charcoal is ASTM Standard D3803-1989, ``Standard Test Method for

Nuclear-Grade Activated Carbon.'' ASTM D3803-1989 is updated guidance

based on an NRC verification and validation effort on ASTM D3803-1979,

which is updated guidance based on RDT M 16-1T. The essential elements

of the ASTM D3803-1989 test are as follows:

70-percent or 95-percent RH.

2-hour thermal stabilization, with air at 30 deg.C

[86 deg.F].

16-hour pre-equilibration (pre-sweep) time, with air at

30 deg.C [86 deg.F] and plant-specific RH.

2-hour equilibration time, with air at 30 deg.C [86 deg.F]

and plant-specific RH.

1-hour challenge, with gas at 30 deg.C [86 deg.F] and

plant-specific RH.

1-hour elution (post-sweep) time, with air at 30 deg.C

[86 deg.F] and plant-specific RH.

The major differences between the ANSI N509-1976 and ASTM D3803-

1989 standards for charcoal testing are as follows:

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

Major differences ASTM D3803-1989 ANSI N509-1976

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

Pre-Equilibration (Pre-Sweep) 30 deg.C [86 deg.F] 25 deg.C [77 deg.F].

Temperature.

Challenge Temperature................. 30 deg.C [86 deg.F] 80 deg.C [176 deg.F].

Elution (Post-Sweep) Temperature...... 30 deg.C [86 deg.F] 25 deg.C [77 deg.F].

Total Pre-Test Equilibration.......... 18 hours 5 hours.

[[Page 9587]]

Tolerances of Test Parameters......... Smaller Larger.

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

As stated above, ASTM D3803-1989 challenges the representative

charcoal samples at 30 deg.C [86 deg.F] rather than at 80 deg.C

[176 deg.F]. The quantity of water retained by charcoal is dependent on

temperature, and less water is retained as the temperature rises. The

water retained by the charcoal decreases its efficiency in adsorbing

other contaminants. At 30 deg.C [86 deg.F] and 95-percent RH, charcoal

will retain about 40 weight-percent water. At 80 deg.C [176 deg.F] and

95-percent RH, charcoal retains only about 2 to 3 weight-percent water.

Because most charcoal is anticipated to be challenged at a temperature

closer to 30 deg.C [86 deg.F] rather than 80 deg.C [176 deg.F], the

lower temperature test condition of ASTM D3803-1989 will yield more

realistic results than would a test performed at 80 deg.C [176 deg.F].

ASTM D3803-1989 specifies a test temperature of 30 deg.C [86 deg.F]

for both the pre- and post-test sweep rather than 25 deg.C [77 deg.F].

There is little difference in the adsorption behavior of charcoal

between these two temperatures. A temperature of 25 deg.C [77 deg.F] is

more conservative; however, the increase from 25 deg.C [77 deg.F] to

30 deg.C [86 deg.F] does not represent a significant variation in the

test results.

ASTM D3803-1989 provides results that are reproducible compared to

RDT M 16-1T because it has smaller tolerances on various test

parameters, and it requires that the charcoal sample be pre-

equilibrated for a much longer period. The longer pre-equilibration

time is more conservative because it will completely saturate the

representative charcoal sample until it is in the condition to which

the subject charcoal adsorbers are expected to be exposed during

design-basis conditions. Therefore, testing in accordance with ASTM

D3803-1989 will result in a more realistic prediction of the capability

of the charcoal.

TS Testing Reference

Laboratory tests of the charcoal are typically required (1) once

every refueling outage, (2) when certain events occur that could

adversely affect the ability of the charcoal to perform its intended

function, and (3) following a defined period of ESF system operation.

The TS require demonstration by laboratory testing that the charcoal is

capable of performing at a level greater than that assumed in the NRC

staff's safety evaluation report. If it fails to perform at that level,

the charcoal must be replaced.

The determination of the appropriate test conditions, test

protocol, and acceptance criteria for laboratory testing of nuclear-

grade activated charcoal is frequently not a straightforward process.

It sometimes requires a complex journey through a number of documents

to ascertain the appropriate test conditions, test protocol, and

acceptance criteria. As described earlier, if the plant has STS, the

STS reference Regulatory Position C.6.a of RG 1.52 for the requirements

for the laboratory testing of charcoal. Regulatory Position C.6.a

refers to Table 2 of the regulatory guide. Table 2 references Test 5.b

of Table 5-1 of ANSI N509-1976. Test 5.b from Table 5-1 references the

test method from paragraph 4.5.3 of RDT M 16-1T (date not indicated),

but specifies that the test is to be conducted at 80 deg.C [176 deg.F]

and 95-percent RH with pre-loading and postloading sweep at 25 deg.C

[77 deg.F]. This test is referred to as the ``25-80-25 test.''

Also contributing to the potential confusion are the various ways

in which TS are written, and conflicting NRC guidance on testing,

particularly NRC letters to the nuclear industry and NRC papers

presented at national conferences. This problem arose from the evolving

understanding of what constituted an appropriate test. At various

times, the NRC has stated that the newest version of a standard can be

used and the test can be conducted at a temperature of 30 deg.C [86

deg.F]. At other times, the NRC indicated that the TS are requirements

and that the tests must be performed at the 25-80-25 conditions. In

various forums, the NRC has also stated that a technical argument may

be made for using the newer standard. However, in some instances when

newer standards were utilized to demonstrate conformance with the TS,

the NRC required licensees to submit TS amendment requests because the

newer standards were not referenced in the TS. Therefore, it is

understandable that licensees may be confused about laboratory testing

protocols, testing conditions, and acceptance criteria. As a result,

many licensees are not testing charcoal in accordance with their TS,

although the tests they conduct may be more conservative than the tests

required by the TS.

Additionally, the 25-80-25 test has difficulties in that none of

the protocols in any version of RDT M 16-1T or ASTM D3803 addresses

performing the laboratory test at multiple temperatures as required by

ANSI N509-1976. If the test protocol described in paragraph 4.5.3 of

RDT M 16-1T (1973) is followed verbatim, a thermal step change must be

made after the 5-hour pre-equilibration period to increase the

temperature from 25 deg.C [77 deg.F] to 80 deg.C [176 deg.F] for

the challenge period. The problem with such thermal step changes is

that they result in condensation forming on the charcoal. The

condensation of free water in the sample bed is cause for aborting the

test, according to the 1977 version of RDT M 16-1T and subsequent

versions of ASTM D3803. Therefore, the 25-80-25 test cannot be

performed pursuant to any existing test protocol.

Because paragraph 4.5.3 cannot be followed verbatim, a few

licensees have changed the 25-80-25 test to thermally equilibrate the

charcoal before introducing the challenge gas. Following the pre-sweep

conditioning at 25 deg.C [77 deg.F], the bed temperature is raised to

80 deg.C [176 deg.F] before introducing the challenge gas. Although

such testing does not cause condensation in the test rig, it is not

acceptable because the results are not easily reproducible, and even

when the test is successfully completed, the results may not be

conservative.

Section 2 of ANSI N509-1976 states for the various documents that

supplement ANSI N509 that the issuance of a document in effect at the

time of the purchase order shall apply unless otherwise specified. In

the case of charcoal, the purchase order date could be considered the

date that the charcoal is procured. Therefore, TS that have the STS

wording may allow the licensee the flexibility to use a more recent

laboratory protocol than the 1973 version of RDT M 16-1T, depending on

the procurement date for the charcoal, without a TS change. However,

although the flexibility of protocol selection exists, the requirement

to perform a 25-80-25 test for those plants that have TS that reference

either Revision 1 or Revision 2 of RG 1.52, Table 5-1 of ANSI N509-

1976, or ANSI N510-1975 can only be relieved by license amendment.

[[Page 9588]]

Categorization of Plants

Since February 1996, the staff has issued three emergency TS

changes to licensees that had determined that the tests they performed

were not in compliance with their TS, because the required testing

standards and test protocols did not support a test in which the

temperature is changed as required by the TS. If the temperature in the

test apparatus is changed from 25 deg.C [77 deg.F] to 80 deg.C [176

deg.F] during the test without modifying the test protocol, water

condenses on the charcoal, thereby causing the test to be aborted (to

fail). The emergency TS changes were issued for the V.C. Summer, Davis-

Besse, and Oconee facilities. The details of these TS changes are

discussed below.

On February 10, 1996, the licensee for the V.C. Summer Nuclear

Station, South Carolina Electric & Gas Company (SCE&G), requested an

emergency TS change. The systems involved were the control room

emergency ventilation system and the fuel handling building exhaust

system. On February 10, 1996, the NRC granted the emergency TS change.

The emergency TS change was requested because SCE&G had determined that

laboratory tests of the charcoal of the control room ventilation system

and the fuel-handling building system had not been performed in

compliance with the V.C. Summer TS. The laboratory test performed for

V.C. Summer was a 25-25-25 test in lieu of the 25-80-25 required by its

TS. The licensee had been performing the 25-25-25 test because, in

consultation with its testing laboratory, it concluded that performance

of the 25-80-25 test would result in condensation on the charcoal and,

thus, an invalid test.

On March 29, 1996, the Toledo Edison Company requested an emergency

TS change for the Davis-Besse plant. The systems involved were the

hydrogen purge, the shield building emergency ventilation, and the

control room. The TS for Davis-Besse required the laboratory test to be

performed in accordance with RG 1.52, Revision 2. In this case, the

licensee was performing a 30-30-30 test using the testing protocol of

ASTM D3803-1979 in lieu of the 25-80-25 test. On March 29, 1996, the

NRC granted the emergency TS change to allow the 30-30-30 test.

On April 2, 1996, Duke Power Company requested an emergency TS

change for the Oconee Nuclear Station. The systems involved were the

reactor building purge, the spent fuel pool ventilation, and the

penetration room ventilation. The TS for Oconee required the laboratory

test of charcoal to be performed in accordance with ANSI N510-1975,

which requires the performance of the 25-80-25 test. However, the

licensee was actually performing a 30-30-30 test using the test

protocol of ASTM D3803-1989. The NRC granted an emergency TS change on

April 2, 1996, to permit the 30-30-30 test.

In each of these cases, the test performed to demonstrate

compliance with TS provided results that the staff considered closer to

reflecting the capability of the charcoal than the test required by the

TS. In addition, the licensees believed that using the newer standard

would satisfy their TS requirement. Their bases for this belief were

the limitations of the test referenced in RG 1.52, their interpretation

of ANSI N509 as allowing the use of later versions of the test

protocol, and some of the guidance provided by the NRC. In the case of

Oconee, the test actually performed is the test that the staff believes

is the appropriate one, ASTM D3803-1989. However, because these tests

had not been conducted in compliance with the plant's TS, each licensee

would have had to shut down its plant or remain in a cold-shutdown mode

until the test required by the TS could be successfully performed, or

until the TS were amended.

On March 21, 1996, Carolina Power & Light Company flew a charcoal

sample from the Brunswick standby gas treatment system (SGTS) to its

testing laboratory in Ohio for the performance of the 25-80-25 test to

comply with the Brunswick TS before restart of an idle unit. The

Brunswick TS required that the laboratory tests be performed in

accordance with Revision 1 of RG 1.52. Previously, the licensee

directed its testing laboratory to perform an 80-80-80 test. To perform

the 25-80-25 test, the laboratory equilibrated the charcoal to 80

deg.C [176 deg.F] before introducing the challenge gas. The licensee

has not requested a TS change for Brunswick to correct the problem and

is awaiting guidance from the NRC.

As a result of the emergency TS changes, the staff has performed an

internal survey of operating plant TS to determine whether other plants

have the potential for similar problems with compliance. The survey

indicated that at least one-third of operating reactor licensees may

not be in compliance with their TS because they reference the flawed

25-80-25 testing protocol and may have used later versions of the

standards for the laboratory tests of their nuclear-grade charcoal. On

the basis of this survey, the staff established the following four

categories of plants:

(1) Plants in compliance with their TS that test in accordance with

ASTM D3803-1989.

(2) Plants in compliance with their TS that test in accordance with

a test protocol other than ASTM D3803-1989.

(3) Plants not in compliance with their TS that test in accordance

with ASTM D3803-1989.

(4) Plants not in compliance with their TS that test in accordance

with a test protocol other than ASTM D3803-1989.

The licensees in Category 1 have TS that require charcoal to be

tested in accordance with ASTM D3803-1989, which adequately

demonstrates the capability of the charcoal. The licensees in Category

2 have TS that require charcoal to be tested in accordance with test

standards other than ASTM D3803-1989. The licensees that received

emergency TS changes were in Categories 3 and 4. Licensees in

Categories 3 and 4 have TS that require charcoal to be tested in

accordance with the 25-80-25 test.

Enclosure 2

Sample Technical Specifications

For Plants With Improved Standard Technical Specifications

C. Demonstrate for each of the ESF systems that a laboratory test

of a sample of the charcoal adsorber, when obtained as described in

[Regulatory Guide 1.52, Revision 2], shows the methyl iodide

penetration less than the value specified below when tested in

accordance with ASTM D3803-1989 at a temperature of

30 deg.C [86 deg.F] and greater than or equal to the relative humidity

specified below.

[[Page 9589]]

[GRAPHIC] [TIFF OMITTED] TN25FE98.003

Note: The use of any standard other than ASTM D3803-1989 to test

the charcoal sample may result in an overestimation of the

capability of the charcoal to adsorb radioiodine. As a result, the

ability of the charcoal filters to perform in a manner consistent

with the licensing basis for the facility is indeterminate.

ASTM D3803-1989 is a more stringent testing standard because it

does not differentiate between used and new charcoal, it has a

longer equilibration period performed at a temperature of 30 deg.C

[86 deg.F] and a relative humidity (RH) of 95% (or 70% RH with

humidity control), and it has more stringent tolerances that improve

repeatability of the test

[GRAPHIC] [TIFF OMITTED] TN25FE98.004

When ASTM D3803-1989 is used with 30 deg.C [86 deg.F] and 95% RH

(or 70% RH with humidity control) is used, the staff will accept the

following:

Safety factor 2 for systems with or without humidity

control.]

For Plants With Older Technical Specifications

Each engineered safety feature (ESF) ventilation system shall be

demonstrated OPERABLE:

a. At least once per 18 months or (1) after any structural

maintenance on the HEPA filter or charcoal adsorber housings, or (2)

following painting, fire, or chemical release in any ventilation zone

communicating with the system by:

(1) Verifying, within 31 days after removal, that a laboratory test

of a sample of the charcoal adsorber, when obtained in accordance with

Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March

1978, shows the methyl iodide penetration less than [see note in

preceding section titled ``For Plants With Improved Standard Technical

Specifications'']% when tested in accordance with ASTM D3803-1989 at a

temperature of 30 deg.C [86 deg.F] and greater than or

equal to a relative humidity of [see note in preceding section titled

``For Plants With Improved Standard Technical Specifications'']%.

b. After every 720 hours of charcoal adsorber operation, by

verifying, within 31 days after removal, that a laboratory test of a

sample of the charcoal adsorber, when obtained in accordance with

Regulatory Position C.6.b of Regulatory Guide 1.52, Revision 2, March

1978, shows the methyl iodide penetration less than [see note in

preceding section titled ``For Plants With Improved Standard Technical

Specifications'']% when tested in accordance with ASTM D3803-1989 at a

temperature of 30 deg.C [86 deg.F] and greater than or

equal to a relative humidity of [see note in preceding section titled

``For Plants With Improved Standard Technical Specifications'']%.

Dated at Rockville, Maryland, this 19th day of February 1998.

For the Nuclear Regulatory Commission.

Jack W. Roe,

Acting Director, Division of Reactor Program Management, Office of

Nuclear Reactor Regulation.

[FR Doc. 98-4761 Filed 2-24-98; 8:45 am]

BILLING CODE 7590-01-P