ML20207N348

Safety Evaluation Supporting Amend 123 to License NPF-1

ML20207N348
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	01/07/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20207N332	List: ML20207N330 ML20207N337 ML20207N348
References
NUDOCS 8701140146
Download: ML20207N348 (2)

Text

l 8 6 UNITED STATES 8 h NUCLEAR REGULATORY COMMISSION

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3 ~E WASHINGTON, D. C. 20555

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDPENT N0.123 TO FACILITY OPERATING LICENS5'NO. NPF-1 PORTLAND GENERAL ELECTRIC COMPANY THE CITY OF EUGENE, OREGON PACIFIC POWER AND LIGHT COMPANY TROJAN NUCLEAR PLANT DOCKET NO. 50-344 INTRODUCTION Emergency Core Cooling System (ECCSI pumps are tested periodically by operating them in recirculation flow loops dedicated to this function. During this testing operation the performance of the pump is determined by comparing an observed parameter to a requirement in the Trojan Technical Specifications. Portland General Electric Company (the licensee) has requested that the performance criterion be changed from pump discharge pressure to pressure rise across the pump, and that the satisfactory performance criterion for residual heat renoval (RHR) pumps be lowered from 165 psig (pounds per square inch gage) to 157 psid (pounds per square inch differential), a decrease of 5%.

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11 DISCUSSION AND EVALUATION The Trojan Technical Specifications presently requires that the ECCS pumps demonstrate that they are capable of achieving a satisfactory discharge pressure while providina flow through the recirculation loop. The licensee has reouested that the requirement for this measurement be changed from discharge pressure to pressure rise across the pump while the pump is operating in its recirculation

loop. The centrifugal charging pump requirement would become 2400 psid rather l than 2400 psig, the safety injection pump requirement would be 1455 psid versus l 1455 psig, and the RHR pump requirement would be 157 psid versus 165 psia. The l reason for this change is to make pump performance measurement independent of suction pressure.

The licensee has made the request to decrease the RHR pump performance criterion from 165 psid to 157 psid because the installed RHR pumps are not capable of meeting the 165 psid performance criterion. Westinghouse has run an analysis of the impact on the plant of a 5% reduction in RHR pump performance using an approved ECCS evaluation model. The 5% reduction in pump differential pressure does not affect the normal operational functions of the RHR system. Under large break LOCA conditions the reduction in pump output results in 1140 lbs. less water being pumped into the reactor vessel from the time pumped injection starts to the time peak clad temperature (PCT) turnaround is reached 47.59 seconds later.

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This is approximately .25 seconds longer than if pump provided full output.

Assuming the most conservative heat up rate for the fuel cladding of 42"F per second results in a PCT increase of 11 F over the present value calculated by the FSAR analysis of 1970"F plus 20 F to account for the flow diversion from the core. (This resulted from a change of flow direction from down flow to up flow on the baffle exterior to alleviate the concern over fuel failures due to baffle

,ietti ng. ) This results in a PCT of 2001"F. The regulatory limit on PCT for Zircaloy cladding is 2200 F.

The licensee's proposed change to the Technical Specification requiring ECCS pump performance criteria in terms of psid versus psig for measuring pump performance is acceptable. The licensee's request to lower the RHP pump performance requirement from 165 psig to 157 psid is considered acceptable because pump output at the reduced differential pressure is adequate to maintain a 199*F margin before the regulatory limit for peak clad temperature would be exceeded. The reduced output of the pump is still adequate to meet the normal operational requirements of the RHR system.

ENVIRONMENTAL CONSIDERATION -

This amendment involves a change in the installation or use of a facility component 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 Comission has previously published a proposed finding that the amendment involves no sianificant 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 CFP 651.22(c)(9). Pursuant to 10 CFR 651.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the ameriment.

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 regulations, and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Dated: January 7, 1987 PRINCIPAL CONTRIBUTOR:

R. Karsh