ML20078Q410

Safety Evaluation Supporting Amends 115 & 104 to Licenses NPF-10 & NPF-15,respectively

ML20078Q410
Person / Time
Site:	San Onofre
Issue date:	02/13/1995
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20078Q391	List: ML20078Q389 ML20078Q410
References
NUDOCS 9502210238
Download: ML20078Q410 (3)

Text

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UNITED STATES j

.j NUCLEAR REGULATORY COMMISSION t

WASHINGTON, D.C. 20EE4001 1

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDHENT NO.115 TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO.104 TO FACILITY OPERATING LICENSE NO. NPF-15 SOUTHERN CALIFORNIA EDISON COMPANY SAN DIEGO GAS AND ELECTRIC COMPANY THE CITY OF RIVERSIDE. CALIFORNIA THE CITY OF ANAHEIN. CALIFORNIA i

l SAN ONOFRE NUCLEAR GENERATING STATION. UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362 i

1.0 INTRODUCTION

By letter dated December 30, 1993, as supplemented by letters dated June 3, I

1994, August 25, 1994, January 3 and 19, 1995, Southern California Edison Company, et al. (SCE or the licensee) submitted a request for changes to the Technical Specifications (TS) for San Onofre Nuclear Generating Station (SONGS), Unit Nos. 2 and 3.

These submittals contain the licensee's justification to replace the current TS with a set of TS based on the CE Owners Group Improved Standard Technical Specifications (STS) issued by the NRC Staff as NUREG-1432 in September 1992. The adoption of Owners Group approved TS is part of an industry-wide initiative to standardize and improve TS. SONGS Units 2 and 3 are the lead plants for adoption of the CE Owners Group standardized TS.

This Safety Evaluation (SE) addresses the licensee's request to implement one provision of the improved STS program in advance of the implementation of the entire program. This provision is a revision to TS Table 3.3-1, " Reactor Protective Instrumentation," to allow the use of the source range neutron flux monitors in place of safety related excore monitors in Modes 3, 4, and 5, with the reactor trip circuit breakers open or the Control Element Assembly (CEA) i Drive System not capable of CEA withdrawal, for the purpose of monitoring core i

reactivity changes. By letter dated January 30, 1995, the licensee forwarded l

TS pages in the current format for the change evaluated by this SE.

The initial notice in the Federal Register included the letters dated December l

30, 1993, June 3, 1994, and August 25, 1994. The additional information contained in the January 3, 19, and 30, 1995, letters were clarifying in i

nature, within the scope of the initial notice and did not affect the NRC i

staff's proposed no significant hazards consideration determination.

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.. 4 2.0 EVALUATION The excore safety channels are necessary to monitor core reactivity changes and are the primary means of detecting and triggering operator actions to respond to reactivity transients. The safety function of the excore detectors during shutdown with the Reactor Trip Breakers (RTBs) open or the CEA Drive System not capable of CEA withdrawal is to provide indication of core reactivity changes and to alert operators of any unexpected increase in reactivity (neutron flux).

The existing Table 3.3-1, Functional Unit 3.b, requires two out of 4 safety related excore monitoring channels to be operable in Modes 3, 4, and 5.

To ensure the operability requirement is met, only two out of the 4 channels can be removed out of service at any given time for maintenance / surveillance testing during these modes of operation.

The licensee proposes to use the source range neutron flux monitors in place of safety related excore monitors in Modes 3, 4, and 5, with the RTBs open or the CEA Drive System not capable of CEA withdrawal, for the purpose of monitoring core reactivity changes. The source range channels are more sensitive than the safety related excore channels during these modes of operation and therefore provide a more accurate indication of reactivity changes. The source range channels include an audible alarm function with a procedurally adjustable setpoint designed to alert operators in the event of an unexpected reactivity change such that an inadvertent criticality is avoided.

In these modes of operation, the safety channels or the source range channels would be used for monitoring purposes only. Neither the safety channels nor the source range channels provide automatic equipment control function which directly affect plant equipment to initiate an accident. The use of source range neutron flux detectors had already been evaluated and incorporated into the normal operating procedures during these modes and explicitly credited in the Updated Final Safety Analysis Report (UFSAR) baron dilution event. The use of the source range channels with the RTBs open or the CEA Drive System incapable of CEA withdrawal does not compromise any safety function or create any new possibilities for equipment malfunction. Therefore, operation of the facility in accordance with this proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

The use of the source range neutron monitors in place of the excore monitors in Modes 3, 4, and 5, with the RTBs open or the CEA Drive System not capable of CEA withdrawal, is permitted by NUREG-1432, and has been incorporated by the licensee in their improved STS submittal. The proposed modifications to TS Table 3.3-1 to include this provision are consistent with the TS cn this subject in both NUREG-1432 and the licensee's improved STS submittal. Since the implementation of this provision in advance of approving the entire improved STS submittal has no adverse impact on other portions of the current TS, and since the source range monitors are fully capable of performing the

required monitoring requirements, the staff concludes that the proposed changes to TS Table 3.3-1 are acceptable.

3.0 STATE CONSULTATION

In accordance with the Commission's regulations, the California State official was notified of the proposed issuance of the amendment. The State official had no comments.

4.0 ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to '5e installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. 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 Commission has previously issued a proposed finding that the amendments involve no significant hazards considera-tion, and there has been no public comment on such finding (59 FR 49434).

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 Commission 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 Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Mel B. Fields Date:

February 13, 1995

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