ML17286A999
| ML17286A999 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 08/09/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17286A998 | List: |
| References | |
| NUDOCS 9108200183 | |
| Download: ML17286A999 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 93 TO FACILITY OPERATING LICENSE NO. NPF-21 WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO.
2 DOCKET NO. 50-397
1.0 INTRODUCTION
By letter dated October 4, 1990, Washington Public Power Supply System proposed certain changes to the Technical Specifications for Nuclear Project No.
2 (WNP-2).
These changes were to accommodate new design features implemented during 1990 in compliance with the ATWS Rule (10 CFR 50.62).
Four changes are proposed to the TS Section 3/4.3.4 RECIRCULATION PUMP TRIP ACTUATION INSTRUMENTATION.
l.
Action statement b is clarified to recognize the design change to allow channels to be placed in the trip condition without causing an ATWS-RPT actuation.
2.
An additional action is required to verify that one trip system is operable within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> when one or more channels are inoperable.
3.
The completion time for reaching Mode 2 is reduced from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
4.
The "Minimum Operable Channels Per Trip System" is revised in Table 3.3.4.1-1 from 1 to 2.
- 2. 0 EVALUATION In the NRC's safety evaluation report on WNP-2 compliance with ATWS rule, the staff requested that the plant Technical Specification on "ATWS Recirculation Pump Trip System Instrumentation" be changed to reflect the design modification.
The modified system uses coincident logic to trip both recirculation pumps and both recirculation pump Low Frequency Motor Generator (LFMG) sets during an ATWS event.
Channel A low vessel water level or high vessel pressure coincident with Channel C low vessel water level or high vessel pressure will trip the recircu-lation pump breaker A and LFMG-A.
Channel B low vessel water level or high'essel pressure coincident with Channel D low vessel water level or high vessel pressure will trip the recirculation pump breaker B and LFMG-B.
The proposed TS change recognizes that, in the modified design, a channel can be placed in the trip condition without causing an ATWS Recirculation Pump Trip actuation.
Action statement b states that, "with the number of OPERABLE channel per trip function less than required by the minimum OPERABLE channels per trip system requirement, verify operability of one trip system within one hour and restore the inoperable channel(s) to OPERABLE status or place the inoperable channel(s) in the tripped condition
- within 14 days.
Otherwise be in at least STARTUP with the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />."
9l082OOSSS 9S0809 PDR ADOCN, 05000397 P
- Only applicable if placing the inoperable channel(s) in trip would not resul t in a recirculation pump trip.
On Table 3.3.4.1-1 "ATWS RECIRCULATION PUMP TRIP SYSTEM INSTRUMENTATION," the "MINIMUMOPERABLE CHANNELS PER TRIP SYSTEM" will be revised from "I" to "2" to reflect the modified design.
The staff finds that with the one-out-of-two-twice logic, tripping a channel will satisfy half of the logic and a valid signal on one of the other two channels will cause a recirculation pump trip.
Therefore, placing an inoper-able channel in the tripped condition will not inhibit an ATWS-RPT should an ATWS event occur.
In conclusion, the staff finds that the proposed TS changes to the WNP-2 TS Section 3/4.3.4 "RECIRCULATION PUMP TRIP ACTUATION INSTRUMENTATION" are consistent with the modified design which enhances the system's ability to respond to and mitigate the consequences of an ATWS event.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Washington State official was notified of the proposed issuance of the amendment.
The State official had no coranents.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes 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 NRC 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 cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding.
Accordingly, the 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 the amendment.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed
- above, that:
(I) there is reasonable assurance that the health and safety of the public wi 11 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:
H. Li Date:
August 9, 1991
I