ML20078C356
| ML20078C356 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 01/19/1995 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20078C354 | List: |
| References | |
| NUDOCS 9501260275 | |
| Download: ML20078C356 (3) | |
Text
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.E UNITED STATES 1
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- NUCLEAR REGULATORY COMMISSION l
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WASHINGTON, D.C. 20555-0001 i
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NOS. 84 AND 45 TO FACILITY OPERATING LICENSE NOS. NPF-39 AND NPF-85 l
PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION. UNITS 1 AND 2
. DOCKET NOS. 50-352 AND 50-353
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1.0 INTRODUCTION
By letter dated August 25, 1993, as supplemented August 4,1994, the Philadelphia Electric Company (the licensee) submitted a request for changes to the Technical Specifications (TS) (Appendix A) of Facility' Operating License Nos. NPF-39 and NPF-85 for the Limerick Generating Station, Units 1 and 2.
The proposed TS change would revise TS Section 3.3.7.8.2-and associated Bases 3/4.3.7.8 regarding the Main Control Room (MCR) Toxic Chemical (Gas) Detection system as a result of installing a third toxic gas i
- monitoring channel and modifying the actuation logic for a high toxic gas actuation signal. The actuation logic would be revised to provide two-out-of-three logic for a high toxic gas actuation signal as opposed to the current one-out-of-two logic. The supplement provided clarifying information that did t
not change the initial proposed no significant hazards consideration i
determination.
2.0 EVALUATION In reviewing the original design and logic for the toxic chemical detection j
system, the staff reported in Section 6.4 of its Safety Evaluation Report (NUREG-0991) that during a postulated hazardous chemical release, detection and alarm capabilities at Limerick will ensure that control room personnel can don breathing apparatus before the toxic gas concentration in the control room i
could exceed the applicable toxicity limits.
l The toxic chemical detection system is a non-safety-related system designed t
to protect MCR personnel from the effects of an offsite release of toxic chemicals. The system is provided to detect toxic chemicals, provide annunciation in the control room, and identify the chemical and concentration l
to a control room console. The Toxic Chemical Isolation Mode is an accident mode of operation for the MCR. During a high toxic gas concentration alarm in.
the MCR, plant procedures require MCR personnel to don self-contained breathing apparatus (SCBA) and take manual action to isolate the normal MCR Heating, Ventilation, and Air Conditioning (HVAC) and initiate the Control r
l Room Emergency Fresh Air Supply (CREFAS) system.
i 9501260275 950119 PDR ADOCK 05000352 P
i The licensee has proposed a plant modification to change the design of the high toxic gas concentration alarm logic. Currently, two chemical analyzers are installed with a one-out-of-two logic to cause an MCR high toxic gas concentration alarm. The modification will add a third chemical analyzer and require that two out of the three chemical analyzers must detect toxic gas concentrations at or above the detector setpoint to cause an MCR high toxic gas concentration alarm. The intent of the modification is to reduce the probability of false high toxic gas alarms. The "two-out-of-three" alarm logic will be maintained by the " Auto-Trip" selector switch that will be installed for each of the three chemical analyzers. The selector switch will be used to place an inoperable analyzer in a tripped condition. Placing the selector switch in the tripped condition provides one of the two inputs required to initiate the high toxic gas concentration alarm.
The existing TS 3.3.7.8.2 action statement for an inoperable toxic chemical detection system requires the system be restored to operable within 7 days, or within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> initiate and maintain operation of at least one control room emergency filtration system subsystem in the chlorine isolation mode of operation. The action statement also states with both toxic gas detection systems inoperable, within I hour initiate and maintain operation of at least one control room emergency filtration system subsystem in the chlorine isolation mode of operation.
The proposed TS action statement for one toxic gas detection. subsystem inoperable, is to place the inoperable subsystem in the tripped condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
If two toxic gas detection system subsystems are inoperable, place one inoperable subsystem in the tripped condition within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, restore one inoperable detection subsystem to operable status within 7 days, or initiate and maintain operation of at least one control room emergency filtration subsystem in the chlorine isolation mode of operations.
If three toxic gas detection subsystems are inoperable, within I hour initiate and maintain operation of at least one control room emergency filtration subsystem in the chlorine isolation mode of operation.
The modification should improve the reliability of the system and decrease spurious actuations.
The TS changes will provide operability of the system consistent with the original TS; however, it also allevs for greater flexibility by allowing operation with an additional channel out-of-service because of the addition of the third channel. Therefore, the staff finds the toxic chemical detection system, the change to the TS 3.3.7.8.2 Limiting Condition for Operation, and Bases 3/4.3.7.8 acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Pennsylvania State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendments involve 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 Comission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public coment on such finding (58 FR 50971). Accordingly, the amendments meet 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 amendments.
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 amendments will not be inimical to the comon defense and security or to the health and safety of the public.
Principal Contributor:
J. Zimerman Date: January 19, 1995
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