ML20205G196
| ML20205G196 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 10/25/1988 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20205G121 | List: |
| References | |
| NUDOCS 8810280208 | |
| Download: ML20205G196 (2) | |
Text
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((f Mtg UNITED STATES g
NUCLEAR REGULATORY COMMISSION E
8 WASHING TON, D. C. 20555 t>,
SAFETY EVALUATION RY THE OFFICE OF NUCLEAR PFACTOR REGULATION SUPPORTING AMENDMENT NO. 119 TO FACILITY OPERATING LICENSE NO. OPR-3 YANKEE ATOMIC ELECTRIC COMPANY a
j YANKEE NUCLEAR POWER STATION DOCKET NO.50-029 INTRODUCTION P
By letter dated June 27. 1988 Yankee Atomic Electric Company (YAEC or the licensee) submitted a request for changes to the Yankee Nuclear Power Station (YNPS or the plant) Techn$ cal Specifications (TS).
The orcposed change would increase the nitrogen supply pressure to the safety injection accumulator in TS 3.5.1.e. from 473 10 psig to 488 25 psig.
DISCUSSION Pressure fluctuations in the safety injection accumulator nitrogen header, due to changes in ambient temperature coupled with regulating valve setpoint drift, have caused the pressure to ruge beyond the current TS value of 10 psi. This results in putting the plut in an ACTION STATEMENT due to the 4
accumulator being declared inoperable.
The licensee requested the increase from 10 psi to 225 psi to avoid this problem.
EVALUATION in the current TS. the minimum nitrogen supply pressure to the accumulator is 473 psig -10 psi or 463 psig.
In the proposed change, the minimum is 488 l
psig -25 psi or 463 psig; thus, there is no change in the minimum pressure.
l However, the maximum pressure resulting from the change increases froft 473 L
psig +10 psi or 483 psig in the current TS to 488 psig +25 psi or C13 psig for the proposed change. This represents an increase in maximum pressure of 513 psig -483 psig or 30 psi.
l The staff evaluated this 30 psi increase in regard to the design limits of the affected mechanical components, vessels, piping and valves.
In Section i
212 of the Final Safety Analysis keport (FSAR). we found thJt the affected l
piping and vessels have a design pressure of 550 psig and that the safety l
valves are appropriately set for this design pressure.
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The staff also evaluated the effect of the 30 psi pressure increuse on the YNPS loss-of-coolant-accident analysis.
Specifically, our evaluation focused on how the fuel peak clad temperature would react in the unlikely event of l
5 such an accident to the citrogen pressure increase.
The licensee stated in l
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L their submittal that their analysis of this pressure increase showed a slight decrease in peak clad temperature. This is a favorable result. We reviewed FSAP Section 411. "Loss of Coolant Accident," and determined that the prer,sure increase would cause more rapid refilling of the primary system with borated cooling water.
This would have the dual effect of absorbing more heat from the core while safety injection systems came on-line and providing negative reactivity to the core.
The net effect would be a decrease in peak clad temperature; thus, we agree with the licensee's analysis.
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Based on the above, we conclude that the 30 psi increase in nitrogen pressure in TS 3.5.1.e is acceptable.
ENVIRONMENTAL CONSIDERATION This amendment involves a change to a requirement with respect to the instal-lation or use of facility components located within the restricted area as defined in 10 CFR Part 20.
The 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 this amendment involves no significant hazards consideration and there has been no public comment on such finding. Accordingly, this amendment meets the eligi-bility 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.
CONCLUSION The staff has concluded, based on the considerations discussed above, that:
1 (1) there is reasonable assurance that the health and safety of the public I
will 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 this amendment will not be inimical to the common defense and security or to the health and safety of the public.
ACKNOWLEDGEMENT Principal Contributor: Norton B. Fairtile Dated:
October 25, 1988 j
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