ML20105D221
| ML20105D221 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 09/16/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20105D217 | List: |
| References | |
| NUDOCS 9209240471 | |
| Download: ML20105D221 (5) | |
Text
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% e. j SAFETY EVALVATION BY THE OfflCE Of NUCLEAR REACTOR REGULATION RuAIED TO AMENDMENT NOS,170 AND U4 10 FACILITY OPERATING LICENSE NOS, OPR-44 and OPR-56 MLADI1PulA 1LLCTR10. COMPANY ITELIC SERVICE ELLCTRIC AND GAS COMPANY D111ARVA POWER AND_11GHT COMPAN(
ATLANilf CITY ELECTRIC COMPANY i
EIACF BOTTOM ATOMIC POWER STATION. UNIT N05._E AND 3 DOCKET N05. 50-277 AND 50-278
1.0 INTRODUCTION
Dy letter dated January 10, 1992 Philadelphia Electric Company (PEco), Public Service Electric and Gas Company, Delmarva Power and Light Company, and Atlantic City Electric Company (the licensees) requested an amendment to the Peach Bottom Atcmic Power Station (PBAPS) Unit Nos. 2 and 3, Technical Specifications (TSs) regarding a revision to the allowable out of service time (A0T) for the emergency service water (ESW) system pumps.
In addition, the licensee proposed revisions to the operability and surveillance requirements of components included in the amergency heat sink (EH!) systs9, edditional surveillance requirements foi the ESW system, and changes to the TS Bases reflecting the above additions and revisions, in response to a staff request, the licensee provided additional information with regard to the proposed TS amendment by letter dated April 3, 1992.
Furt'er clarification of the Probabilistic Risk Assessment (/RA) analysis performed by the licensee was obtained through a telephone conversation witi PECo representatives on April 10, 1992.
By letter dated July 20, 1992, the licensee revised the January 10, 1992 submittal.
The revision corrected discrepancies between the description of the proposed changes and the marked up TS pages.
The July 20, 1992 submittal did not change the substance of the January 10, 1992 submittal.
The April 3, 1992 and July 20, 1992 letters provided clarifying information that was not outside the scope of the original Federal Reaister Notice and did not change the initial proposed no significant hazards consideration dete*mination.
2.0 ILAQ1PQVHQ The ESW system consists of two parallel full capacity ESW pumps, and associated piping, heat exchangers, valves and controls. The EHS system consists of one full capacity emergency cooling water (ECW) pump, two parallel full capacity ESW booster pumps, an induced draft emergency-cooling tower (ECT) with an integral water storage reservoir, and associated piping, valves 920924047; 920916 DR ADOCK 0500 7
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and controls.
ESW and EHS system components are supplied with AC pow r from the emergency buses to allow operation during a loss of off-site powar (LOOP).
The ESW system provides the only supply of cooling water to the emergency diesel generators (EDGs). Under normal oMrating conditions, the non-safety-related normal service water (NSW) system supplies cooling water to emergency core cooling system (ECCS) components, ECCS pump roem coolers, and reactor core isolation cooling (RCIC) pump room coolers.
When the NSW supply is unavailable, such as following a LOOP, and an ESW pump is operating, a check valve arrangement allows the ESW system to automatically begin supplying these heat exchangers with cooling water.
The licensee has not conclusively demonstrated that the ECW pump end the associated EHS system is equivalent to an ESW pump in performing the ESW pump safety function.
However, the piping arrangement and system performance characteristics are such that the ECW pump is capable of supplying sufficient cooling water flow to the ESW system to meet design basis flow requirements to the EDGs, ECCS components, ECCS pump room coolers, and RCIC pump room coolers.
The licensee recognized the following deficiencies with regard to the current PBAPS TSs:
centinued operation with one ESW pump inoperable is not addressed; continued operation with two ESW pumps inoperable is allowed for a period not to exceed one month; and tha ECW pump and the associated EHS system is permitted to be considered equivalent to an ESW pump.
The licensee partially addressed these deficiencies through Plant On-site Review Committee (PORC)
Position No. 33 by imposing administrative limits on plant operation with one or two ESW pumps inoperable, and by administratively prohibiting consideration of the operability of the ECW pump and the associated EHS system as equivalent a the operability of one ESW pump.
In order to fully address the above noted TS deficiencies, the licensee proposed revisions to the PBAPS TSs which include:
an additional limiting condition for operation (LCO) requiring a reactor shutdown to the cold shutdown condition within 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; should one ESW pump remain inoperable for a period in excess of 7 days; a revised LC0 requiring the reactor be placed in not shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold shutdown within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> should both ESW pumps become inoperable; and deletion of the section permitting establishment of ECL ind ESW pump equivalency.
The licensee's proposed changes to the PBAPS.
I TSs also include the following:
addition of a requirement to test the ECW and l
ESW booster pumps in accordance with Section XI of the ASME Bciler and Pressure Vessel Code and applicable addenda, except where relief has been granted, effectively reducing the surveillance test interval (STI) for these pumps from once every operating cycle to once every three months; a reduction of the STI for the ECT fans from once per operating cycle to once every three months; addition of a surveillance test cequirement for valve position verification consistent with the standard iss; and addition of a surveillance test requirement to inspect and clean the ESV pump ir'ake structure once every l
operating cycle.
In addition, the licensee prootse. cevisions to the TS Bases I
reflecting the above changes and other changes of a purely administrative nature.
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3-3.0 EVALUATION J
Doe to the differences in configuration between the PBAPS ESW aystem and the generic plant service water system described in the standard TSs, the staff could not directly apply the guidance of the standard TSs with regard to i
establishing A0Ts for ESW system components at PBAPS. The staff based the
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review of the proposed 7-day A0T for a single inoperable ESW pump on the rulative importance of ESW to other equipment required to cope w!th design basis events.
The Itcensee performed an analysis to enmpare the relative impact on core damage frequency of an assumed unavailability of 7 days per year for the high pressure toolant injection (HPCI) system and each EDG to that for a 7-day-per-year unavailability for each ESW pump. Operation of the ECW pump was not credited in the analysis.
The licensee determined that the impact of the assumed unavailability of a single r.SW. pump on core damage frequency was _less than that of any one EDG or the HPCI system.
Since the A0T for a single inoperable EDG and the-A0T for an inoperable HPCI system both equal 7 days. -
the licensee concluded that a 7 der A0T was appropriate for a single inoperable ESW pump.
Th staff determined the accident sequences of primary concern with regard to ESW pump unavailability to be those sequences involving a total LOOP. These sequences are critical due'to the importance of an ESW system cooling water supply to the EDGs following a LOOP. Without adequate cooling to.the EDGs in this situation, a station blackout scenario results. Under station blackout conditions, the HPCI-or RCIC systems are assumed to provide adequate core cooling for-several hours. Failure of the HPCI or RCIC systems is likely to e
result from battery depletion or extreme environmental conditions in that periou of time.
Sequences involving a loss of NSW for reasons other than a LOOP are much less important due to the. substantial period of time available to provide cooling to the necessary components prior to failure.
The staff considered the significance of a total loss of ESW, the likelihood of a.
concurrert LOOP and the A0Ts for equipment designed.to cope with an SB0 event.
The staff considered that the significance of the ESW pump to the SB0 event was similar to that of the HPCI, RCIC and Automatic Depressurization System (ADS) systems, e ch of which has a 7-day A0T for a single inoperable component. 'The staff also noted that the proposed 7-day A0T for a-single inoperable ESW pum) was significantly more conservative than the current 30-day A0T.
In macing the above determination, the staff considered the ECW
. pump to be unavailable.
Based on'the above analyses,-the staff finds the proposed 7 day A0T for a-single-inoperable ESW pump acceptable. The staff also finds the proposed LCO requiring that the reactor be placed in hot shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and cold-shutdown within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> should both ESW pumps become inoperable to.be consistent with the severity of the situation and,-therefore, acceptable, I-Since the licensee has not conclusively demonstrated that the ECW ) ump and the associated fHS' system is equivalent to an ESW pump in performing-tie ESW pump l
safety function, the staff considers the proposed deletion of the TS section L
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permitting establistment of ECW and ESW pump equivalency appropriate und finds tne proposed change acceptable.
The proposed addition of a requirement to test the ECW and ESW booster pamps
'n accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable addenda, except where relief 'as bcen granted, complies with the requirements of 10 CFR 50.55a wit', regard to inservice testing of ASME Code Class 2 and Class 3 pumps, and is acceptable.
Based on licenste review of the test pracecare, the proposed reduction of the Sil for the ECT fans from on:e per operating cycle to once every three months introduces no additional unavailability for the EHS system.
Since the proposed STI for the ECT fant, increases the level of confidence in their proper operation without increating unavailability and is consistent with the proposed STI for other active ccmponents in the EHS system, the staff finds'the proposed change in the ELT fan Sil acceptable, m
lhe proposed addition of a surveillance test requirement for valve position verification is consistent with the guidance of the standard TSs and is, therefore, acceptable.
The proposed addition of a surveillance tett requirement to inspect and clean the ESW pump intake structure once every operating cycle complies, in part, with the recommendations of Generic letter 89-13.
Therefore, the staff finds the addition of this surveillance requirement acceptable.
4.0
SUMMARY
1he proposed revision to the pBAPS ISs related to the ESW and EHS systems was re.'iewed and found to be acceptable.
The acceptaoility of the proposed A0T for a single inoperable ESW pump was based on a staff review of the significance of a total loss of ESW, the likelihood of a concurrant LOOP and the A0T for other equipment needed to cope with an SB0 event.
The remaining proposed revisions to the PBApS TSs were found to De acceptable based on various guidance documents and requirements, including the standard TSs.
It should be noted that the proposed revisions, as a whole, result in TSs significantly more restrictive than the currera TSs.
The proposed changes to '
the 15 Bases were found to accurately reflect the rationale for the proposed revisions to the pBAPS TSs and were, therefore, acceptable.
An editoria! change was made to Technical Specifications pages 221, of Units 2 and 3, with the concurrence of the licensee, to add f to 120' to read 120*f.
This change did not ef fect the original no significant hazards consideration.
5.0 ELAH CONSMT AT10B in accordance with the Co.r. mission's regulations, the Pennsylvania State official was notified of thc groposed issuance of the amendments.
The State official had no comments.
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6.0 EfWIRONMENTAL CONSIDERATION Thc amendments change a requirement with respect to installation or use of a facility component locited within the restricted area as defined in 10 CFR
?irt 20 and changes the surveille.nce requirements.
The NRC staff has determined that the amendiaents 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 i
occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on such finding (57 TR 4492).
Accordingly, the amendments meet the eligibility criteria for categori':al exclusion sut forth in 10 CTR 5).22(c)(9).
Pursuant to 10 CFR Sl.22(b) no eavironmental impact statement s r environmental assessment need be prepared in colnection wl;h the insuance of the amendments.
7.0 [0tKUQJfgj The Commission t as conclLded, bas'd on the considerations discussed above, that:
(1) there is reasonable assu.ance that the health and safety of the public will not be end:ngered by operation in the proposed manner, (2) such activities will be conducted in compliance wit 1 the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the-common defense and security or to the health and safety of the public.
Principal ContriL1 tors:
S. Jones J. Shea Date: September 15, 19?2 f
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