ML20044C267
| ML20044C267 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 03/10/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20044C265 | List: |
| References | |
| NUDOCS 9303190362 | |
| Download: ML20044C267 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.124TO FACILITY OPERATING LICENSE NPF-5 GEORGIA POWER COMPANY. ET AL.
EDWIN 1. HATCH NUCLEAR PLANT. UNIT 2 DOCKET NO. 50-366
1.0 INTRODUCTION
By letter dated November 10, 1992, Georgia Power Company, et al. (the licensee), proposed a temporary revision to the Technical Specifications (TS) for the Edwin 1. Hatch Nuclear Plant, Unit 2.
The proposed temporary revision to Hatch Unit 2 TS 3.6.6.1 concerns the operability of Hatch Unit I standby gas treatment system (SGTS). This temporary revision will allow both subsystems of the Unit 1 SGTS to be simultaneously inoperable for a cumulative total of up to 7 days during Unit 2 power operation for the purpose of installing the torus hardened vent pursuant to the recommendations of NRC Generic Letter (GL) 89-16, " Installation of a Hardened Wetwell Vent."
t.0 EVALUATION As a result of the NRC Mark I containment Performance Improvement Program, NRC GL 89-16 encouraged licensees to install a hardened wetwell vent under the provisions of 10 CFR 50.59.
By letter dated October 24, 1989, the licensee informed the NRC that both Plant Hatch units would install hardened vents.
Unit 2 TS recuires the operability of two Unit 2 SGTS subsystems and two Unit 1 SGTS subsystems. This is based on a Unit 2 design basis accident (DBA) loss-of-coolant accident (LOCA) and takes into consideration the secondary containment (SC) design for the two units.
Following a DBA LOCA on Unit 2, it is postulated a certain amount of leakage will occur out of the Unit 2 primary containment.
Some of this leakage will go into the Unit 2 reactor building area, and some will go up through the shield blocks above the Unit 2 primary containment into the Unit I and Unit 2 common area above the refueling floor.
Therefore, to contain and treat the radioactive gases postulated to leak out of the Unit 2 primary containment, the SGTS must be able to simultaneously maintain a negative pressure in the SC of both units.
Four operable SGTS subsystems can fulfill this requirement given the single failure of one of the subsystems.
If one of the four subsystems is inoperable, a 7-day limiting condition for operation (LCO) is entered per Action a of TS 3.6.6.1.
If two of the four subsystems are inoperable, immediate shutdown is required by Action b of TS 3.6.6.1.
Safe Unit 2 operation can be met with only the two Unit 2 SGTS subsystems operable by taking advantage of a Unit 1 TS which allows reconfiguration of the Unit 1 SC.
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. Unit 1 TS 3.7.C.2 provides for a reconfiguration of the Unit 1 SC referred to as modified Unit 1 SC.
In the modified SC mode, the Unit I reactor building area is segregated from the Unit I and Unit 2 comon area above the refueling floor such that these two air volumes do not comuniccte.
In this configuration, given a Unit 2 DBA LOCA, the SGTS is only required to maintain a negative pressure in the Unit 2 reactor building area and the Unit I and Unit 2 comon area above the refueling floor. Two of the four SGTS subsystems can maintain a negative pressure in these areas.
During the time when both Unit 1 SGTS subsystems are inoperable for installation of the containment hardened vents, the Unit 1 SC will be maintained in the modified configuration per Unit 1 TS 3.7.C.2, and both Unit 2 SGTS subsystems will be maintained operable.
Furthermore, the licensee stated that to provide a greater level of safety, several compensatory measures will be taken during the time when both Unit 1 SGTS subsystems are inoperable for the installation of the containment vent.
Based on its review, the staff finds that the revision to TS 3.6.6.1 has no adverse impact on safety and does not pose an undue risk to public health and safety. Therefore, it is aceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Georgia State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (58 FR 6997 dated Februry 3, 1993).
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The Comission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Comission's regulations, and (3) the issuance of the amendment will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor: K. Jabbour i
Date: March 10, 1993
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