ML20034C886
| ML20034C886 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 05/11/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20034C884 | List: |
| References | |
| NUDOCS 9005210041 | |
| Download: ML20034C886 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION
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W ASHINGTON, D. C. 20555
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l SAFETY EVALUATION BY THE OFFICE OF NUCLE _AR, REACTOR REGULATION l
ret.ATED TO AMENDMENT NO.159TO FACILITY OPERATING LICENSE NO. NPF-1 PORTLAND GENERAL ELECTRIC COMPANY THE CITY OF EUGENE. OREGON PACIFIC POWER AND LIGHT COMPANY, TROJAN NUCLEAR PLANT DOCKET NO. 50-344
1.0 INTRODUCTION
An NRC Safety System Functional Inspection in August 1986'found that i
under design basis seismic conditions automatic isolation of the nonseismic (Category II) portion of the component cooling water (CCW) system might i
not occur rapidly enough to prevent blowdown of both CCW trains, thereby rendering the safety-related portion of the system inoperable. The i
licensee, Portland General Electric Company (PGE), therefore, committed to upgrade the CCW system by seismically supporting the nonseismic portion of the system.
PGE proposed that during the interim, while 3
modifications were being completed, the CCW system be operated in a
" split-train" configuration with the interface isolation valves for one train normally closed and with all three CCW pumps maintained in en operable status. The licensee also proposed changes in'the Technical Specifications (TS)thatprovidethesamelevelofprotectionandsafety 5
in the interim configuration as was already pt;oided in the TS before-the interim configuration.
The upgrading of the nonseismic portion of the CCW system has since been completed. The split-train operation is therefore no longer necessary and the TS should be restored to the previous state allowing for cross, connected operation between the two safety-related trains of CCW.
By letter dated November 13, 1989, the licensee proposed TS changes that will restore this cross. connected operation as originally designed and
- licensed, i
2.0 DISCUSSION AND EVALUATION The CCW System provides heat removal from safety-rehted and non-safety-related components during normal. operation, shutdown and cooldown of the reactor, and from safety-related components after any accident leading to j
9005210041 900511 ADOCK03OO{g4 DR 1
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-2 an emergency shutdown.
In addition, the CCW System provides a monitored, intermediate barrier between Reactor Coolant System lRCS) and the heet sink provided by the Service Water System (SWS).
The portion of the CCW L
System that supplies cooling water to Engineered Safety Feature (ESF) l equipment is safety-related and complies with the appropriate regulatory requirements with regard to design, equiprant qualification, redundancy and separation.
l The CCW System consists of two Seismic Category I flow paths, each of which serves a single train of identical ESF equipment and a common Seismic Category II, non-safety-related flow path.
Each CCW train has air-operated interface isolation valves to provide automatic isolation of the Seismic Category I portion of the system from the Seismic Category (SIS) portion of the system upon receipt of a safety injection 11 signal or a low CCW surge tank level signal. One purpose of this
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automatic isolation capability is to ensure that the failure of Seismic-Category 11 equipment and components (including piping) does not adversely affect the operation of ESF. equipment essential to safe shutdown of the Plant.
7 During the NRC August 1986 Safety System Functional Inspection ($$FI),
it was determined that in the event of a full area rupture of the Seismic Category 11 piping due to a seismic event, the automatic interface isolation valves might not close fast enough to prevent blowdown of the safety-related portion of the two CCW trains. This.could result in a complete loss of CCW. To preclude this scenario from occurring, the CCW System was aligned in a split-train configuration with one train isolated from the Seismic Category 11 flow path during Modes 1 through 4 This configuration would ensure a continuous flow of CCW to at least one train of ESF equipment following a seismic event.
In addition to aligning the CCW System in a split-train configuration, the spare CCW pump was main-tained operable during Modes 1 through 4 to assure the availability of a e
CCW loop even with a single-failure concurrent with a seismic event. The i
Trojan CCW Technical Specifications were amended to ensure the system was operated in the split-train configuration with the spare pump operable until the Seismic Category 11 portion of the system could be upgraded during the 1989 refueling outage. That upgrade has since been completed, and the interim split-train operation is no longer required to provide the-1 level of protection and safety comparable to that intended in the original TS. The licensee has therefore proposed to change the-Trojan TS to revert from the current split-train operating configuration and operability requirements of the spare pump to the originally analyzed and licensed operating configuration of the Component Cooling Water (CCW) System.
The licensee's letter dated February 4, 1988 requesting the TS change for
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split-train operation stated an intent to revert to the original CCW-TS after completion of modifications to the Seismic Category 11 portions of the system. Aside from the fact the split-train configuration of operation that was temporarily adopted is not the design that was originally approved and licensed, continued operation in the long-term s
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under the requirements to maintain split-train operation and a spare CCW l
-pump operability is not warranted or desirable because such requirement and operation ~ will cause entry into the Atit0N statement of TS '3.7.3.1
,Lif a CCW pump is declared inoperable.
Entry into the ACTION statement l
under the condition specified is not now warranted, since completion of the modifications makes such action unnecessary in order to maintain the level of safety and protection afforded in the original licensed configura-i tion.
The staff has evaluated the proposed changes to the Trojan TS 3/4.7.3 and associated Bases and on the basis of the foregoing considerations finds the proposed changes to be acceptable.
3.0 CONTACT WITH STATE OFFICIAL The NRC staff has notified the Oregon Department of Energy of the proposed issuance of this amendment along with the proposed determination of no t
significant hazards consideration. No coments were received.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change in a requirement with respect to the
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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, leased offsite,and n icant change in the types, of rny effluents that may be re 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 significant hazards consideration and-there has been no public coment 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 $0NCLUS10N 1
Wehaveconcluded,basedontheconsiderationsdiscussedabove,that(1)there is reasonable assurance that the health and safet of the public will not be endangered by operation in the proposed manner, (y) such activities will be 2
conducted in compliance with the Comission's regulations, end (3) the issuance of the amendment will not be inimical to the comon defense and-security or to the health and safety of the public.
PRINCIPAL CONTRIBUTOR:
Roby Bevan j
r Dated: May 11. 1990 I
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