ML17157A334
| ML17157A334 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/20/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17157A333 | List: |
| References | |
| NUDOCS 9010010094 | |
| Download: ML17157A334 (6) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO.
100 TO FACILITY OPERATING LICENSE NO.
NPF-14 AND AMENDMENT NO. 68 TO FACILITY OPERATING LICENSE NO.
NPF-22 PENNSYLVANIA POWER 8r LIGHT COMPANY ALLEGHENY ELECTRIC COOPERATIVE INC.
DOCKET NOS. 50-387 AND 50-388 SUS UEHANNA STEAM ELECTRIC STATION UNITS 1
AND 2
- 1. 0 INTRODUCTION By letter dated February 12, 1990 (PLA-3338), Pennsylvania Power 8 Light Company (PPSL),
proposed to amend temporarily the Appendix A of Facility Operating License Nos.
NPF-14 and NPF-22 for operation of Susquehanna Steam Electric Station (SSES),
Units 1 and 2.
The requested amendment furnished information to support the proposed RHR Service Water (RHRSW) and Emergency Service Water System (ESW) modifications.
PPAL proposed one time changes to Technical Specifications that extend the allowable Limiting Condition for Operation (LCO) time for suppression pool spray and cooling modes of RHR, RHRSW, and Emergency Service Water (ESW) from 3 days to 7 days to allow RHRSW and ESW systems modifications.
These temporary technical specification changes are effective only during the RHRSW/ESW modifications.
The proposed Technical Specification changes allow the RHRSW/ESW modifications to take place without requiring a dual unit shutdown'.
These modifications on Loop A of the RHRSW/ESW, which is shared by both units, are presently scheduled for the Unit 1 5th refueling outage which is expected to start on September 8, 1990.
Modifications on Loop B of RHRSW/ESW, which is also shared by both units, is planned for the Unit 2 4th refueling outage which is expected to start on March 9, 1991.
Only one loop, which affects both units, is isolated at any time.
- 1. 1, Modifications Planned The RHRSW check valves of the RHR heat exchangers, which are used for isolation and are leaking, will be replaced by ball valves for easy heat exchanger inspection and maintenance.
A new butterfly valve, drain connections and a
new 3" connection, etc., will be added to the RHRSW system.
The new 3" connection to the RHRSW system will shorten the time.
required to set up the diesel driven fire pump to inject water into the reactor pressure vessel (RPV) in an emergency.
The ESW system modification, which upgrades the keep fill system, will allow the spray pond bypass valve to be normally kept open rather than normally closed, thereby increasing the reliability of ESW cooling for diesel generators.
90fQQ)0094 900920 PDR ADOCK 05000387 P
- 2. 0 EVALUATION The RHRSW is designed to supply cooling water to the RHR heat exchangers of both units.
The ESW is designed to supply cooling water to the four Emergency Diesel Generators (EDGs),
RHR pumps, ECCS pump room coolers and RCIC pump room coolers.
{During normal plant operation, both RHRSW and ESM systems are on standby.
They are only started during a LOCA.)
When RHRSW and ESW Loop A on both units are isolated for modifications, Loop 8 on both units will still be available and vice versa.
The modifications will be performed with the outage unit defueled.
- Hence, the system requirements for the outage unit are less stringent and the effect of the one loop unavailability is not significant.
Normal Technical Specifications apply fo'r the outage unit.
All four EDGs get cooling water supply from both Loops A and 8 of ESW.
During the loss of one ESW loop, redundancy of ESW supply to EDGs will be lost.
Redundancy for the operating unit will be lost for many systems during the LCO.
RHR pumps, core spray
ESW Loops.
During loss of ESW loop A, ECCS and RCIC pump rooms wi 11 still be cooled by ESW Loop B.
In addition, RHR pumps A
and 0 will be lost for long term cooling, since their motor oil and seal water are cooled by Loop A ESW; but RHR pumps 8 and C will be operable for long term cooling since their cooling water is supplied from Loop 8 ESW.
Also, all core spray pumps will be operable since there are no cooling water requirements for their operation during a
LOCA.
During the loss of Loop A of RHRSW, RHR heat exchanger A will be inoperable.
But during the
From the discussions above, it is clear that with no failure during an accident, sufficient normal safety systems will still be available.
When one RHRSW and ESW loop is isolated, two RHRSW pumps and two ESW pumps still will be available.
Only on RHRSW pump and one ESW pump are required for safe shutdown of the plant.
One ESW pump can supply the ESW to all four diesel generators.
All the pumps are scheduled to be tested before the modifications.
All valves in the RHRSW and ESW system will be lined up for emergency conditions.
No valve actuations are required.
Only the pumps are required to be started.
Since there is only one shutdown cooling path during the
- LCO, PPSL identified RWCU blowdown mode as the alternate shutdown mode.
During this mode, reactor water is drawn from the reactor recirculation system and reactor vessel bottom
- drain, and is pumped through the regenerative and non-regenerative heat exchangers.
The cleanup filter and demineralizer units, and the return path to the regenerative heat exchanger are bypassed, and the water is directed to either the main condenser or the liquid radwaste tank.
Even though PPSL has not demonstrated the RWCU blowdown mode of operation, analysis by PPSL and ANL has shown that this mode is feasible for decay heat removal.
Since offsite AC power is required for its operation, this mode will not be useful during a
RWCU blowdown can be given credit as a backup to the normal shutdown cooling method when offsite power is assumed to be available.
PP&L already issued the emergency procedure for RWCU blowdown mode.
't Since RWCU will not function during loss of offsite power, PP8L identified RCIC operation as the backup to RWCU.
RCIC will allow the plant to be kept on hot standby for at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> until RHR pumps become available.
It should be noted that RHR pumps are not required for shutdown cooling until the reactor pressure is reduced to about 150 psig.
During this period, RCIC is used instead of the main condenser to remove decay heat.
In case RCIC is not available, core spray pumps can inject suppression pool water into the reactor and back through the main steam safety/relief valves.
RHR can be aligned to provide suppression pool cooling when the RHR pumps become available.
During a
LOCA, core spray pumps which are not affected by the modifications will be available for reactor makeup.
Diesel fire pumps can be used for reactor makeup as a last resort.
Even though the LCO is allowed for 7 days, the system can be put into service in case of emergency during 4 days out of 7 days.
The actual system isolation is planned only for 3 days.
There are two independent segregated offsite power sources for the site.
The modifications will be performed only if both offsite power sources are available.
During the LCO, no testing or maintenance wi 11 be planned for the operating unit.
Technical S ecification Chan es (a)
Sections 3.6.2.2, 3.6.2.3 Suppression pool spray and suppression pool cooling.
When one RHRSW loop is taken out of service, one suppression pool spray loop also becomes inoperable.
The TS requires the inoperable loop to be operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Otherwise, plant shutdown will be required within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
The proposed one time TS change will allow the loop to be inoperable for 7 days to facilitate the modifications.
This is acceptable.
(b)
Sections 3/4.7.1 Service Water System.
The present TS requires the inoperable RHRSW or ESM to be operable within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Otherwise, plant shutdown will be required within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.
The proposed one time change will allow the RHRSW to be inoperable for 7 days to facilitate the modifications.
This is acceptable.
The proposed technical specification changes are temporary, effective only during installation of RHRSW/ESW modifications taking place during outages of September 1990 for Unit I and March 1991 for Unit 2.
Only one RHRSW/ESW loop is to be taken out for modification at any time.
The period of the LCO with the extension is seven days.
During the period of the extended LCO, two of
a 1'
four pumps will be operable in the operable loop of RHRSW and ESW, with only one of two pumps required to accomplish the safety function for each system.
Valve line-ups to accomplish the safety function and pump testing will be performed just prior to entering the extended action statement.
Consequently,
+he probability of fai lure on demand of either RHRSW or ESW is judged to remain acceptably low with one loop cut of service.
Moreover, in the unlikely event that either system was challenged and failed, alternate methods of decay heat removal as discussed above could be used until the RHRSW or ESW loop undergoing modification could be put back into service.
Based on continued high availability of operable RHRSW and ESW loop, and availability of alternate decay heat removal methods, the staff finds the licensees proposed extension to the LCO period acceptable.
- 3. 0 ENVIRONNENTAL CONSIDERATION These amendments involve changes to a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20.
The staff has determined that these 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 Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding.
Accordingly, these amendments meet the elioibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 61.22(b),
no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLOSION The Commission made a proposed determination that the amendment involves no significant hazards consideration which was published in the Federal Re ister (55 FP, 33992) on August 20, 1990 and consulted with the Coamonnwea t i o Pennsylvania.
No public comments were received, and the Commonwealth of Pennsylvania did not have any comments.
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public wi,ll not be endangered by operation in the proposed
- manner, and
('2) such activities will be conducted in compliance with the Commission's regulations and the issuance of these amendments will not be inimical to the common defense and security nor to the health and safety of the public.
Principal Contributor:
G. Thomas Dated:
September 20, 1990