ML20065F406
| ML20065F406 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 09/19/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20065F404 | List: |
| References | |
| NUDOCS 9010100045 | |
| Download: ML20065F406 (5) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR. REGULATION SUPPORTING AMENDMENT NO.
45.TO FACILITY.0PERATING LICENSE.NO. NPF-39 PHILADELPHIA ELECTRIC COMPANY
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LIMERICK GENERATING. STATION. UNIT.1 i
DOCKET NO. 50-352
1.0 INTRODUCTION
By letter dated June 1,1990, Philadelphia Electric Company (the licensee)
Limerick Generating Station (LGS)y Operating License No. NPF-39 for the requested an amendment to Facilit
, Unit 1.
The proposed amendment would i
revise the Technical Specifications (TS) to reflect two fire protection modifications which the licensee has committed to perform during the fall of 1990 refueling outage of Unit 1.
d Modification No. I would replace the existing suppression pool water l
temperature indication (actually the water temperature at the suction of the'A'ResidualHeatRemovalpump)attheRemoteShutdownPanel(RSP)with-direct temperature indication of the suppression pool water by using J
spare resistance temperature detector elements from the existing SuppressionPoolTemperatureMonitoringSystem(SPTMS).
Modification No. 2 would provide the ability at the RSP to manually fire-induced damage prevents the reopening of a valve (power supply when transfer from the normal power supply to the emergency describedbelow) needed to ensure safe plant shutdown.
These modifications are proposed to be performed during the next (third) refueling outage for LGS, Unit 1, currently scheduled to begin in September 1990, based on commitments in Licensee Event Report (LER)
Nos. 1-89-002, " Unavailability of the Reactor Core Isolation Cooling System Due to Insufficient Protection of Yarious Control and Power Cables from Postulated Fire Damage," Rev.'01 dated March 31, 1989, and 1-89-023,"Lackof'ProtectedSuppressIonPoolLevelandTemperature Indication in the Event of a Fire," dated May 5, 1989.
For plants licensed after January 1,1979 (such as LGS, Unit 1), the r2quirements of 10 CFR 50.48 have been incorporated into Appendix R.
2.0 DISCUSSION
Modification No. 1 Ine remote shutdown system instrumentation and '.ontrols located on RSP were designed in accordance with General Design Criterion (GDC) 19 of 10 CFR Part 50, Appendix A to ensure that sufficient capability is available 9010100045 900919
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, l for prompt hot shutdown of the reactor from locations outside of the main control room (MCR) in the event MCR habitability is lost.
The remote L
shutdown system instrumentation and controls are also used to satisfy the shutdown requirements for shutdown from outside of the MCR in the event of a fire. TS Table 3.3.7-4-1, " Remote Shutdown System Instrumentation and Controls," TS page 3/4 3-77, currently reflects that the suppression pool I
water temperature indication at the RSP is actually an indication of the water temperature at the suction of the 'A' Residual Heat Removal (RHR) pump (i.e.,whentheRHRpumpisalignedforsuppressionpoolcooling).
In LER No. 1-89-023 for LGS, Unit 1, the licensee reported that this indication of suppression pool water temperature may be lost in the event of a fire for which shutdown from the RSP is required since the 'A' RHR pump suction water temperature indicator, TI-51-104A, is powered from a non-Class IE electrical power source and its associated cabling is not protected from fire damage.
In LER 1-89-023, the licensee commi*ted to perform a modification during the third refueling outage to provide 1
suppression pool water temperature indication at the RSP which would be i-available to support saa shutdown of the plant from outside the MCR in the event of a fire. This proposed modification will replace the 'A' MR pump suction water temperature indication at the RSP with direct tempt Lture indication of the suppression pool water using spare resistance tempe a ture detector (RTD) elements from the existing SP.'MS.
SPTMS provides suppression l
pool water temperature indication in the MCR only. This proposed modification will provide suppression pool water temperature indication which is powered from a Class 1E electrical power source and for which the associated cabling is protected from fire damage.
l' Once this proposed modification is complete, the TS reference "(Actually l
RHR Pump 'A' Suction Temperature)" for the suppression pool water temperature indication on TS Table 3.3.7.4-1 will no longer be valid.
Therefore, a change is proposed to TS page 3/4 3-77 to delete this reference such that TS Table 3.3.7.4-1 will specify " Suppression Chamber L
Water Temperature" only.
1 Modification No. 2 The Reactor core Isolation Cooling (RCIC) system is used to support certain methods of safe shutdown of the plant in the event of a fire.
In I
LER Po. 1-89-002, the licensee reported that 3 fire in certain areas of the
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plant could result in the unavailability of the RCIC system's steam supply I
line inboard containment isolation valve, HV-49-1F007. This valve is controlled from the RSP in support of safe shutdown from outside the MCR in the event of a fire. Althoug1 the RSP is powered by e1 Wtrical Division 1 AC power, the HV-49-1F007 valve is powered from electri el Division 3 AC j
power, and will automatically close upon receipt of a D' ision 3 isolation l
signal. Howestr Division 3 control and power cables were not protected in
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those fire areas,for which the RCIC system is used to support safe shutdown l
of the plant in the event of a fire.
Fire-induced damage to the Division 3 control cables could produce a false isolation signal which would cause the HV-49-1F007 valve to close.
Fire-induced damage to the Division 3 cables, from the same fire, could cause a loss of power required to reopen the valve.
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If, in the event of a fire, the valve closes and power is lost before the valve can be reopened, the RCIC system would be rendered inoperable.
In LER 1-89-002, the licensee committed to perform a modification during the third refueling outage which would provide the capability, through a manual transfer switch located at the RSp, to power valve HV-48-1F007 from an emergency (Division 1) power source. This emergency power source would be available in the event of a fire to provide the ability to reopen the valve. As part of the proposed modification, this emergency i
source will be powered through a normally locked open, instantaneous magnetic circuit breaker mounted in an electrical Division 1 motor controlcenter(MCC). Also, a second, normally closed, thermomagnetic circuit breaker will be added as a back-up breaker to provide the redundant protection specified by Regulatory Guide 1.63, " Electric penetration Assemblies in Containment Structures for Nuclear Power Plants," for electrical cables and wiring that penetrate the primary i
containment. This second circuit breaker is also required to assure i
capability to disconnect from the Division 1 power bus for any faulted load condition.
Asaresultofthisgroposedmodification,achangeisproposedto TS Table 3.8.4.1-1, Primary Containment Penetration Conductor Overcurrent Protective Devices," TS page 3/4 8-24 The change would add to this table the primary and backup circuit breakers for the Division 1 emergency power supply to the RCIC system's steam supply inboard containment-isolation velve, HV-49-1F007. Both breakers are identifed by a single circuit breaker number 52-21331, since boch breakers are located in the same MCC cubicle. TS Table 3.8.4.1-1. currently lists the primary and backupbreakers(circuitbreakerno. 52-22313) for the normal Division 3 power supply to the HV-49-1F007 valve.
3.0 EVALUATION L
L Modification No I will provide assured suppression pool water temperature monitoring capability which will continue t satisfy GDC 19 of 10 CFR Part 50, Appendix A, since it will provide direct indication of suppression pool water temperature at the RSP instead of the 'A' RHR pump suction water temperature, and it will also provide the operator with the abi1 Gy to select between two temperature elements on opposite sides of the suppression pool to give a better profile of the suppression pool water temperature.
This modification does not add any new interfaces with systems that are not related to suppression pool temperature monitoring. The design temperature monitoring capability of SPTMS is unaffected by the proposed modification. There is no impact on P.HR system operation and the 'A' RHR pump suctbn water temperature indication is still available in the MCR.
l The new temperature instrumentation loop will provide increased reliability j
since its design conforms to applicable criteria for physical separation, redundancy, and divisionalization. This new temperature instrumentation loop will be powered from an electrical Division 1. Class 1E source.
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i Modification No. 2 will provide the RSP operator the ability to manually switch to an emergency power supply. This action may be required to i
reopen valve HV-49-1F007 in the event the valve closes and the normal Division 3 power supply is lost as the result of fire-induced damage caused by a fire in certain areas of the plant. This proposed modification will provide the operators the ability to restore the RCIC system to service in the event the RCIC system is rendered inoperable for the reasons described previously as a result of a fire, and to provide for i
safe shutdown of the plant in accordance with the safe shutdown methods i
described-intheFireProtectionEvaluationReport(FPER)forLGS.
The manual transfer switch box at the RSP will be locked closed. The position of the transfer-switch will be indicated on a MCR panel, and will cause an alarm in the MCR when placed in the emergency position.
The electrical Division 1 instantaneous breaker (the primary breaker) will be locked open. The keys to these locks will be under administrative control so that control of the manual transfer switch and the Division 1 primary breaker will be limited to, aside from testing and maintenance, procedure-directed operator discretion only in the event'of a fire with concurrent loss of electrical Division 3 AC power.
l The design of this proposed modification is such that physical independence of electrical systems and application of the single failure criterion will be maintained, with the exception that when the manual transfer switch is placed in the emergency position, normal Division 3 power and i
control cabling for the valve will become energized from an electrical Division 1 power source. The licensee is establishing appropriate restrictions for testing the operation of valve HV-49-1F007 and appropriate procedural controis on the manual transfer switch. These restrictions i
will limit the time that the electrical Division 1 power source is exposed to the electrical Division 3 wiring loads._ They will also provide additional assurance that the two power divisions will not become interconnected.
r The proposed modifications are acceptable to resolve the fire protection
't deficiencies, along with the associated changes to the TSs.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to the installation or use of a facility com)onent located within the restricted area as defined in 10 CFR Part 20. T1e 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 occupational radiation exposure.
The Comission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public coment on such finding.
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, I Accordingly, this amendment meets the eligibility) criteria for l
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categorical exclusion set forth in 10 CFR 51.22(c (9). Pursuant to l
10 CFR 51.22(b), no environmental impact statement nor environmental l
l assessment need be prepared in connection with the issuance of this l
amendment.
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5.0 CONCLUSION
The Comission made a proposed determination that the amendment involves i.
no.significant ha:ards consideration which was published in the Federal l
3Re ister (55 FR 26288) on June 27, 1990 and consulted with the Comonwealth of Pennsylvania. No public coments were received and the Comonwealth of Pennsylvania did not have any coments.
The staff 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 this amendment will not be l
inimical to.the comon defense and security or to the health and safety' of-the public.
Principal Contributor: Dick Clark Dated:
September 19, 1990 j.
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