ML17285B156
| ML17285B156 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 04/04/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17285B154 | List: |
| References | |
| NUDOCS 9004120021 | |
| Download: ML17285B156 (4) | |
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+**y4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0.80 TO FACILITY OPERATING LICENSE NO.
NPF 21 WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO.
2 DOCKET NO. 50-397
1.0 INTRODUCTION
2.0 By letter dated January 9, 1990, Washington Public Power Supply System (the licensee) proposed an amendment to the Technical Specifications to allow operation of Washington Nuclear Project, Unit 2 (WNP-2) with the safety valve function of at least four safety-relief valves (SRV's) operable in Operational Conditions 1, 2, and 3, when at less than 25 percent rated thermal power.
The existing specifications require that 12 of the 18 SRV's be operable in these conditions.
The staff has reviewed the proposed changes to the Technical Specifications and has prepared the following evaluation.
EVALUATION Currently, because the Supply System does not have a test facility for SRV testing, testing to prove safety-relief valve operability at WNP-2 is performed in-situ.
When a valve is removed for maintenance, it is con-sidered inoperable until the in place test is completed satisfactorily.
In order to confirm the operability of a refurbished valve, testing of the valve lift settings is conducted while the plant is at power with the valve in place.
Current Technical Specifications require that the Safety valve function of 12 of the 18 safety-relief valves be operable in Operational Conditions 1, 2,
and 3.
Under this requirement, only 6 valves can be refurbished during an outage.
Should there be a need to refurbish more than 6 valves at one time, an unnecessary startup and shutdown cycle is required and return to full power is delayed.
The licensee has provided an analysis in support of the proposed change to the WNP-2 Technical Specifications.
An ASME overpressurization transient calculation was performed for the most bounding accident at the low power/flow condition, consisting of rapid closure of all main steam isolation valves (MSIV's), coupled with an assumed failure to scram on the MSIV closure signal.
The overpressurization calculation was performed by ANF using their advanced plant simulator code COTRANSA.
The maximum vessel pressure resulting from this event at low power/flow was calculated 9004i20~2i 900404 PDR ABACK 05000397 P
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The results of this analysis demonstrate that four safety-relief valves have the capacity to prevent the reactor vessel pressure from reaching the established transient pressure safety limit of 1375 psig specified by the ASME pressure vessel code.
On this basis the staff finds the stafety significance to be quite small and the proposed change is acceptable.
Seven of the 18 SRV's also function as automatic depressurization system (ADS) valves as part of the emergency core cooling system (ECCS).
Technical Specification 3.5.1 governs the operability of these seven valves in the ADS mode of operation.
The proposed change to technical specification 3.4.2 wi 11 not change the operability requirements of the ADS valves, which require that seven ADS valves be operable in Operational Conditions 1, 2, and 3, when reactor steam dome pressure is greater than 128 psig.
ENVIRONMENTAL CONSIDERATION 4.0 This amendment involves a change in the installation and use of a facility component located within the restricted area as defined in'10 CFR Part 20.
The staff has determined that this 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 sionificant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding.
Accordingly, this amendment meets 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 this amendment.
CONTACT WITH STATE OFFICIAL 5.0 The Commission made a proposed determination that the amendment involves no significant hazards consideration (55 FR 6126, February 21, 1990) and consulted with the State of Washington.
No public comments were received, and the State of Washington did not have any comment.
CONCLUSION We have 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, and (2) such activities will be conducted in compliance with the Commission s regula-tions and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
A. Almond Dated: April 4, 1990
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