Notice of Amendment to Certificate of Compliance GDP-2 for the U.S. Enrichment Corporation, Portsmouth Gaseous Diffusion Plant, Portsmouth, OH

NUCLEAR REGULATORY COMMISSION

[Docket 70-7002]

Notice of Amendment to Certificate of Compliance GDP-2 for the

U.S. Enrichment Corporation, Portsmouth Gaseous Diffusion Plant,

Portsmouth, OH

The Director, Office of Nuclear Material Safety and Safeguards, has

made a determination that the following amendment request is not

significant in accordance with 10 CFR 76.45. In making that

determination, the staff concluded that: (1) There is no change in the

types or significant increase in the amounts of any effluents that may

be released offsite; (2) there is no significant increase in individual

or cumulative occupational radiation exposure; (3) there is no

significant construction impact; (4) there is no significant increase

in the potential for, or radiological or chemical consequences from,

previously analyzed accidents; (5) the proposed changes do not result

in the possibility of a new or different kind of accident; (6) there is

no significant reduction in any margin of safety; and (7) the proposed

changes will not result in an overall decrease in the effectiveness of

the plant's safety, safeguards, or security programs. The basis for

this determination for the amendment request is described below.

The NRC staff has reviewed the certificate amendment application

and concluded that it provides reasonable assurance of adequate safety,

safeguards, and security and compliance with NRC requirements.

Therefore, the Director, Office of Nuclear Material

Safety and Safeguards, is prepared to issue an amendment to the

Certificate of Compliance for the Portsmouth Gaseous Diffusion Plant

(PORTS). The staff has prepared a Compliance Evaluation Report which

provides details of the staff's evaluation.

The NRC staff has determined that this amendment satisfies the

criteria for a categorical exclusion in accordance with 10 CFR 51.22.

Therefore, pursuant to 10 CFR 51.22(b), no environmental impact

statement or environmental assessment need be prepared for this

amendment.

USEC or any person whose interest may be affected may file a

petition, not exceeding 30 pages, requesting review of the Director's

Decision. The petition must be filed with the Commission not later than

15 days after publication of this Federal Register Notice. A petition

for review of the Director's Decision shall set forth with

particularity the interest of the petitioner and how that interest may

be affected by the results of the decision. The petition should

specifically explain the reasons why review of the Decision should be

permitted with particular reference to the following factors: (1) The

interest of the petitioner; (2) how that interest may be affected by

the Decision, including the reasons why the petitioner should be

permitted a review of the Decision; and (3) the petitioner's areas of

concern about the activity that is the subject matter of the Decision.

Any person described in this paragraph (USEC or any person who filed a

petition) may file a response to any petition for review, not to exceed

30 pages, within 10 days after filing of the petition. If no petition

is received within the designated 15-day period, the Director will

issue the final amendment to the Certificate of Compliance without

further delay. If a petition for review is received, the decision on

the amendment application will become final in 60 days, unless the

Commission grants the petition for review or otherwise acts within 60

days after publication of this Federal Register Notice.

A petition for review must be filed with the Secretary of the

Commission, U.S. Nuclear Regulatory Commission, Washington, DC 20555-

0001, Attention: Docketing and Services Branch, or may be delivered to

the Commission's Public Document Room, the Gelman Building, 2120 L

Street, NW, Washington, DC, by the above date.

For further details with respect to the action see: (1) The

application for amendment and (2) the Commission's Compliance

Evaluation Report. These items are available for public inspection at

the Commission's Public Document Room, the Gelman Building, 2120 L

Street, NW, Washington, DC, and at the Local Public Document Room.

Date of amendment request: November 8, 1996, as modified by USEC

responses dated December 13, 1996, and January 16, 1997, to NRC

requests for additional information dated November 29, 1996, and

December 31, 1996, respectively.

Brief description of amendment: The amendment changes the Technical

Safety Requirement (TSR) Standby Operational Mode definition for the

UF6 Withdrawal Stations by allowing the compression loop vent path to

the cascade to be open. It should be noted that venting of the

Withdrawal Station compression loop to the cascade is routinely done at

PORTS. However, accounting for this procedure was inadvertently left

out of the Standby Operational Mode definition by USEC from its

proposed TSRs which have been approved by the NRC.

Basis for finding of no significance:

1. The proposed amendment will not result in a change in the types

or significant increase in the amounts of any effluents that may be

released offsite.

The proposed change to TSR 2.5.1 permits evacuating UF6 from the

compression loop in the UF6 withdrawal station to the cascade, which

acts as a low pressure sink, in the Standby Operational Mode. This

change will not result in significantly increasing the potential for

unconfinement of UF6 which could lead to an increase in effluents that

may be released offsite since it only involves venting of UF6 from one

portion of process piping, which confines UF6 in the Withdrawal

Station, to another portion of process piping which confines UF6 in the

enrichment cascade. Confinement of UF6 within the cascade is primarily

provided by maintaining the cell high-side (compressor discharge) gas

pressure below 25 psia (TSR 2.2.3.13) and by applying appropriate

quality assurance requirements to process gas piping and equipment

(Safety Analysis Report Section 3.8.2.2). Therefore, this TSR amendment

will not result in significant amounts of effluents that may be

released offsite.

2. The proposed amendment will not result in a significant increase

in individual or cumulative occupational radiation exposure.

Evacuating UF6 from the compression loop to the cascade in the

Standby Operational Mode will not significantly impart additional

occupational radiation exposure. The cascade or the withdrawal loops do

not result in significant occupational radiation exposures. Some of the

reasons being that: (1) The occupancy factor is low, (2) distance from

the source is generally high, (3) significant shielding is provided by

piping and equipment, (4) depleted and low enriched uranium has low

specific activities and are also comparatively low gamma radiation

emitters, (5) most of the uranium is in gaseous form (low density), and

(6) UF6 is confined within quality controlled equipment and piping.

Therefore, any transfer of confined UF6 from the withdrawal station to

the cascade would not measurably modify individual or

[[Page 6279]]

cumulative occupational radiation exposures.

3. The proposed amendment will not result in a significant

construction impact.

Since the proposed changes do not involve any construction,

therefore, there will be no construction impacts.

4. The proposed amendment will not result in a significant increase

in the potential for, or radiological or chemical consequences from,

previously analyzed accidents.

The proposed changes which involve evacuating UF6 from the

compression loop to the cascade (low pressure sink) in the Standby

Operational Mode will not result in a significant increase in the

potential for UF6 releases. In fact, venting the compression loop to

the cascade may enhance safety by minimizing the potential for over-

pressurization of the UF6 withdrawal loop with subsequent confinement

rupture. To avoid enrichment losses, UF6 is vented back to the A-

suction of a compressor in the cascade that has UF6 of similar

enrichment. All A-suction pressures in lines that would receive the

vented UF6 are subatmospheric. Therefore, any confinement failure would

likely result in inleakage as opposed to outleakage. In addition,

cascade units that would receive vented UF6 would likely be comprised

of relatively smaller sized equipment containing relatively smaller

quantities of UF6 since they would be located near the top and at the

bottom of the cascade. Therefore, the proposed change will not result

in a significant increase in the potential for UF6 releases.

Going from a closed compression loop vent path to an open

compression loop vent path will not result in a significant increase

for, or radiological consequences from, previously evaluated

criticality accidents. The likelihood of an accidental criticality in

the cascade due to wet-air (moderator) inleakage would not be increased

significantly for the following reasons:

a. This amendment involves a valve that is internal to several

valves even when the pigtail is not attached to the withdrawal

manifold. These valves would be in the closed position. Therefore,

several misvalving errors would be required to permit significant wet-

air inleakage into the cascade through the compression loop vent valve.

b. To maintain the integrity of the UF6 pressure boundary, USEC is

committed to applying appropriate quality assurance requirements to

process gas piping and equipment (including valves) with diameters of 2

inches or larger.

c. Formation of UO2F2 in the cascade due to significant inleakage

of wet-air would result in compressor vibration and would reduce

barrier permeability thus affecting cascade compressor performance

which would be observed in the control rooms via motor load

indications. Changes in compressor A-suction pressures would also be

detected.

d. Introduction of wet-air into the cascade would be detected on

the line recorders that continuously indicate nitrogen and oxygen

concentrations.

Based on the primary reasons provided above, the proposed TSR

change will also not significantly raise the probability or

consequences of a criticality accident.

5. The proposed amendment will not result in the possibility of a

new or different kind of accident.

For similar reasons provided in the assessment of criterion 4,

evacuating UF6 from the compression loop to the cascade in the Standby

Operational Mode will not result in a new potential accident involving

UF6 releases or criticality. In fact, venting the compression loop to

the cascade may enhance safety by minimizing the potential for over-

pressurization of the UF6 withdrawal loop with subsequent confinement

rupture.

6. The proposed amendment will not result in a significant

reduction in any margin of safety.

As discussed above, from a UF6 release accident standpoint, venting

to the cascade may enhance safety, and from a criticality accident

standpoint, the safety impact is insignificant. This procedure, which

is routine operation at PORTS, will not result in the violation of any

limiting condition of operation. Therefore, the opening of the vent

pathway in the Standby Operational Mode will not significantly reduce

any margin of safety.

7. The proposed amendment will not result in an overall decrease in

the effectiveness of the plant's safety, safeguards, or security

programs.

As discussed above, from a UF6 confinement standpoint venting to

the cascade may enhance the plant's safety program and from a

criticality safety program standpoint, the safety impact is

insignificant.

The staff has not identified any safeguards or security related

implications from the proposed amendment. Therefore, the opening of the

vent pathway in the Standby Operational Mode will not result in an

overall decrease in the effectiveness of the plant's safety,

safeguards, or security programs.

Effective date: This amendment becomes effective at 12:00 noon on

the day following the day issued.

Certificate of Compliance No. GDP-2: Amendment will revise the

Technical Safety Requirements.

Local Public Document Room location: Portsmouth Public Library,

1220 Gallia Street, Portsmouth, Ohio 45662.

Dated at Rockville, Maryland, this 4th day of February 1997.

For the Nuclear Regulatory Commission.

Carl J. Paperiello,

Director, Office of Nuclear Material Safety and Safeguards.

[FR Doc. 97-3322 Filed 2-10-97; 8:45 am]

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