ML20151T499

Application to Amend License NPF-1,consisting of License Change Application 169,revising Tech Specs Surveillance Requirements for ECCS Check Valves

ML20151T499
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	08/12/1988
From:	Cockfield D PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20151T495	List: ML20151T491 ML20151T499 ML20151T595
References
NUDOCS 8808160385
Download: ML20151T499 (4)

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PORTLAND GENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LIGHT COMPANY I

I Operating License NPF-1 l Docket 50-344 l License Chango Application 169 l i

This License Change Application requests modifications to Operating License NPF-1 for the Trojan Nuclear Plant to revise the surveillance requirements for Emergency Core Cooling System check valves in the Trojan Technical Specifications.

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l PORTLAND GENERAL ELECTRIC COMPANY l By l D. W. Cockfield l Vice President Nuclear Subscribed and sworn to before me this 12th day of August 1988.

r i 4 KJ Notary Public of Orefon OMyCommission lup%r [

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8S08160385 DR Geos3m ADOCK 05000344 PDC

4 LCA 169 Page 1 of 3 DESCRIPTION OF CHANGE

1. In Table 3.4.6-1, Reactor Coolant System pressure Isolation Valves, on Page 3/4 4-15a of the Trojan Technical Specifications, Noto (a)5 is added as followa:

"S. When leakage tests are performed using a test diffe-rential pressure lower than the function maximum differential pressure, observed leakage rates shall be adjusted to function maximum differential pressure values".

2. In Section 3/4.4.6.2, Operational Leakage, on Page B 3/4 4-02b of the Trojan Technical Specification Bases, the following is added to the second paragraph:

"Table 3.4.6-1 includes the requirement to adjust observed leakage rates for these isolation valves to function maximum dif ferential pressure values when testing at lower pressures.

This adjustment ensures conservatism since observed leakage rates may be less at lower test differential pressures when the leakage channel opening remains constant with increasing pressure. Observed leakage rates are adjusted using the square root of the ratio of the function maximum differential pressure and the actual test differential pressure. Function maximum differential pressure is defined as that differential pressure which the isolation valve is subjected to under normal Plant conditions during power operations. For isolation valves not subjected to a differential pressure under normal Plant conditions during power operations, hCs pressure is assumed on the high-pressure side of the valve."

REASON FOR CHANGE

1. Table 3.4.6-1 of the Trojan Technical Specifications allows leak testing each valve at a differential pressure lower than the function maximum differential pressure for that valve. However, observed I leakage rates at that lower test differential pressure may be less than leakage rates occurring at the function maximum differential pressure, if the leakage channel opening remains constant with I increasing pressure. Therefore, to ensure conservatism when testing at lower pressures, observed leakage rates shall be adjusted to fune-tion maximum differential pressure values using the square root of the ratio of the function maximum differential pressure and the actual test differential pressure.

2. Trojan Technical Specification Bases 3/4.4.6.2 is expanded to des-cribe the rationale for adjusting observed leakage rates and to define function maximum differential pressure.

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1 LCA 169 page 2 of 3 SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION I

The proposed change does not pose a significant hazard for the reasons a discussed below,'

Revising Table 3.4.6-1 of the Trojan Technical Specifications to require -

an adjustment of observed Icakago rate data to function maximum differ-ential pressure values does nots

a. Involve a significant increase in the probability or consequences J

of an accident.

The proposed change is a more restrictive limitation not pre-sently included in the Trojan Technical Specifications. Applying more restrictive test criteria to the Reactor Coolant System _

(RCS) pressure isolation valvss provides greater assurance of valve integrity, thereby reducing the probability and the conse-quences of an accident.

b. Create the possibility of a new or different kind of accident l j from any accident previously evaluated.  !

l i i The accident of concern is referred to as an intersystem Loss-of- r

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Coolant Accident (LOCA) which involves excessive leakage from a high pressure system (the RCS) to a lower pressure system [the

! Emergency Core Cooling System (ECCS)]. To adequately. monitor the integrity of the high/ low pressure interface (i.e., two in-series check valves), the Technical Specifications provide surveillance i requirements and associated leak-rate limits on these check 1 valves. The proposed change requires that leakage data acquired at differential pressures lower than the function maximum value j be adjusted upward to correspond to the function maximum differ- 1 ential pressure values. The proposed revision involves no physi- j cal alterations of Plant configurations or changes to setpoints i I

) or operating parameters and, therefore, does not create the possibility of a new or different kind of' accident from any 1

l previously evaluated.

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c. Involve a significant reduction in a margin of safety, i The proposed change will improve the margin of safety by requir-

. ing that observed leakage rates are conservatively adjusted to i the higher function maximum differential pressure values when j testing at lower differential pressures. I In the March 6, 1986 Federal Register, the NRC published a list of exam-i ples of amendments that are not likely to involve a significant hasards j consideration. Example No. 2 from this list states

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LCA 169 Pago 3 of 3 "A chango that constitutes an additional limitation, restriction, or control not presently included in the Tocht:ical Specifica-tions, og, a more stringent surveillance requirement".

Based on the above evaluation, the proposed chango does not pose a sig-nificant hazard.

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