ML20006C152

Safety Evaluation Supporting Amends 109 & 87 to Licenses DPR-70 & DPR-75,respectively,changing Min Flow Requirements for RHR Sys from 3,000 Gpm to 1,000 Gpm

ML20006C152
Person / Time
Site:	Salem
Issue date:	01/30/1990
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20006C149	List: ML20006C148 ML20006C152
References
NUDOCS 9002060391
Download: ML20006C152 (3)

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F SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION (I

SUPPORTING AMENDMENT NOS.109 AND 87' TO FACILITY OPERATING i

E LICENSE NOS. DPR-70 AND DPR-75 n

PUBLIC SERVICE ELECTRIC & GAS COMPANY PHILADELPHIA ELECTRIC COMPANY-DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY l

y SALEM GENERATING STATION, UNIT NOS 1 AND 2 I

1 DOCKET NOS. 50-272 AND 50-311 i

1.0 INTRODUCTION

1 By letters dated September 11, 1989 and November 6, 1989, Public Service Electric & Gas Company requested an amendment to Facility Operating License Nos. DPR-70 and DPR-75 for the Salem Generating Station, Unit Nos.

1 1 and 2.

The proposed amendments would change the Salem Generating i

Station Units 1 and 2 Technical-Specifications (TS) and associated Bases to reduce the required Residual Heat Removal (RHR) system flow rate during i

Mode 6 operation. At the currently reouired flow rate of 3000 gpm the RHR 1

system could be subject to vortexing at the RHR pumps suction piping i

during operation with the Reactor Coolant System (RCS) partially drained.

Vortexing can lead to RHR system air entrainment and pump cavitation and subsequent loss of RHR system flow.-

The proposed changes are in partial response to NRC Generic Letters 87-12 l

and 88-17 which requested licensees and applicants with pressur ued water L

reactors (PWR) to evaluate operation of the RHR system under conditions p

when the RCS is partially filled.

Also, Salem 1 LCO and Surveillance Requirements would be renumbered from 3.9.8 and 4.9.8 to 3.9.8.1 and 4.9.8.1, respectively.

t 2.0 EVALUATION i

'2.1 Reduction in Required RHR System Flowrate L

Operation with the RCS partially drained in Modes 5 and 6 is necessary for required inspection and maintenance of RCS components such as reactor i

coolant pumps and steam generators. As indicated in NUREG-1269, " Loss of L

Residual Heat Removal at Diablo Canyon Unit 2," a reduced flowrate would

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provide a greater margin against vortexing and preclude an inadvertent 1

L loss of decay heat removal capability due-to air entrainment and cavitation of the-RHR pumps. As the time after plant shutdown increases, decay heat renoval requirements from the RHR suction flow are reduced since decay heat decreases as a function of time after initial reactor shutdown. The change proposed by the licensee will provide sufficient flowrate to maintain RCS temperature (core and~ upper plenum) less than or equal to 140*F.

In addition, a' minimum flowrate is required to prevent boron stratification to minimize the potential for localized variation in boron concentration in the RCS. For the Salem Generating Station, Westinghouse has recommended a minimum flowrate of 1000 gpm with variable flowrates as a function of._ time after shutdown.

In a related matter, a Unit 1.TS on boron dilution-is proposed for deletion since the minimum flowrate required to prevent boron stratification is identified by the proposed RHR coolant circulation TS change. Since the proposed TS will require that the RHR-flowrate be maintained at least greater than 1000 gpm and sufficient to maintain RCS temperature less than 140 F, the staff finds the proposed Technical Specification modifications to be acceptable.

2 ? Technical Specification Changes The TS changes associated with the proposal are as follows:

l (1) Unit 1 TS Section 4.9.8 Unit 2 TS Section 4.9.8.1 Replace the'3000 gpm minimum flow with a value of 1000 gpm and specify that the RHR loop flow shall be verified to be sufficient to maintain the RCS temperature at less than or equal to 140*F.

(2) Renumber the' Unit 1 LCO and Surveillance Requirements to 3.9.8.1 and j

4.9.8.1 for consistency with Unit 2.

(3) Delete the Unit 1 TS LC0 3.1.1.3 (BORON DILUTION) 4 This LCO is no longer necessary since the potential for boron l

stratification is minimized for flows greater than 1000 gpm and intentional changes in boron concentration will not occur during L

refueling (Mode 6).

'(4) Modify Bases Section 3/4.9.8 to reflect the new TS surveillance-requirements.

The above TS changes are acceptable based on the supporting analyses for the l

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The NRC staff, with the knowledge and concurrence of the licensee, made administrative corrections (punctuation, symbols) to the revised

,3 technical specification pages to bring them into agreement with the marked up technical specification pages.

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3.0 ENVIRONMENTAL CONSIDERATION

These amendments involve a change to a requirement with respect to the installation or use of a f acility component located within the restricted' area as defined in 10 CFR Part 20 and changes to.the surveillance requirements. The 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 Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration and there has been no ublic comment on such finding. Accordingly, the amendments meet the eli ibility criteria for categorical exclusion set forth in 10 CFR51.22(c)9). Pursuantto10CFR51.22(b),noenvironmentalimpact u

stetement or environmental assessment need be prepared in connection with the issuance of the amendments.

4.0 CONCLUSION

The Commission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register (54FR51260)onDecember 13, 1989 and consulted with the State of 3

New Jersey. No public comments were received and the' State of New Jersey i

did not have any comments.

l 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, j

and-(2) such activities will be conducted in compliance with the Commission's regulations and the issuance of the amendments will not be j

inimical to the common defense and security nor to the health and safety of the public.

Principal Contributor:

M. McCoy 1

Dated: January 30, 1990 i

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