ML19338C724

Technical Evaluation Rept on Mod of P-8 Reactor Trip Circuitry,Beaver Valley Nuclear Station,Unit 1.

ML19338C724
Person / Time
Site:	Beaver Valley
Issue date:	07/31/1980
From:	May S EG&G IDAHO, INC., EG&G, INC.
To:	Ross W Office of Nuclear Reactor Regulation
References
CON-FIN-A-6256 EGG-EA-5206, NUDOCS 8008180623
Download: ML19338C724 (4)

Text

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EGG-EA-5206 July 1980 TECHNICAL EVALUATION REPORT ON THE MODIFICATION OF P-8 REACTOR TRIP CIRCUITRY - BEAVER VALLEY NUCLEAR STATION, UNIT 1

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POOR ORIGINAL U.S. Department of Energy Idaho Operations Office

• Idaho National Engineering Laboratory

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3 This is an informal report intended for use as a preliminary or working document NRC Rescarch and Technica' Assistance Report Prepared for the l U.S. Nuclear Regulatory Cocnission Under DOE Contract No. DE-AC07-761D01570 0 FIN No. A6256 g b h E b Idaho 8008180623

h EGcG,..~. . e FOPM EG4G yde re, n rs INTERIM REPORT Accession No.

Report Nc. ECC-EA-5206 Centract Program or Project

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EICS On-call Technical Assistance

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Sublict of this Document:

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Technical Evaluation Report on the Modification of P-8 Reactor Trip Circuitry -

Beaver Valley Nuclear Station, Unit 1 Type of Document:

Informal Report Author (s):

S. E. Mays r

D:ta of Document:

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July 1980 R2sp::nsible NRC Individual and NRC Office or Division:

W. Ross, NRC-DOR This document was prepared primanly for preliminary or internal use. it has not received full review and approval. Since there may be substantive changes, this document should not be considered final.

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EG&G Idaho. Inc.

[ . Idaho Falls. Idaho 83415 1

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Prepareo for the l U.S. Nuclear Regulatory Commission

! Washington, D.C.

Under DOE Contract No. DE-AC07-761001570 NRC FIN No. A6256

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i TECHNICAL EVALUATION REPORT l- MODIFICATION OF P-8 REACTOR TRIP CIRCUITRY j BEAVER VALLEY NUCLEAR STATION, UNIT 1

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Duquense Light i

l Docke t No. 50-334 S. E. Mays i

l RELIABILITY AND STATISTICS BRANCH ETGINEERING ANALYSIS DIVISION EG&G IDAHO, INC.

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! July 8, 1980

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TECHNICAL EVALUATION REPORT MODIFICATION OF ?-8 REACTOR TRIP CIRCUITRY BEAVER VALLEY NUCLEAR STATION, UNIT 1 1.0 INTRODU CTION The purpose of this review is to determine whether or not the proposed modification to the P-8 reactor trip circuitry meets the licensing guidelines o f S RP 7. Specifically, this review will examine the modifications to insure

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that adequate justification exists for bypassing this trip and that no other

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trips are affected.

2.0 CRITERIA SRP 7.2 provides guidelines for review of electrical, instrumentation, and control system (EICS) features of Reactor Trip Systems. IEEE Standard 279 and Regulatory Guide (RG) 1.53 contain single failure criteria. Redundancy

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and njependencecriteriaareinIEEEStandard279andRG1.6. Tes ting requirements are contained in IEEE Standard 279 and RG 1.118.

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3.0 DISCUSSION AND EVALUATION The P-8 permissive in the Beaver Valley 1 reactor trip system insures that a loss of flow in any one reactor coolant loop when reactor power is above 34% will initiate a reactor scram. This trip is initiated either by two of three low flow signals from flow instruments in each loop or by any reactor

coolant pump (RCP) breaker auxiliary relays indicating that power to the pump

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is interrupted. Each of the three flow sensors per loop is powered from independent and redundant vital buses and requires two of three sensors to

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indicate low flow in order to initiate a scram. Thus, no EICS single failures will render this protective feature inoperable. However, failure of any one static inverter power supply can cause a spurious reactor trip by causing the reactor coolant pump breaker auxiliary relays to indicate that the pump has tr ipped. The modification to the P-8 circuitry would eliminate this input to the reactor trip system.

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7he RCP breaker trip is an anticipatory trip and serves as a backup to i

the flow sensors. However, no credit has been taken for this trip in the ,

Beaver Valley 1 safety analyses. Therefore, removal of this trip has no effect on the safety analyses.

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The RCP breaker trip is removed by removing the leads to an electronic "0R" gate. This action has no effect on any other trips and still allows the two of three low flow signals to initiate a scram. This modification has no .

ef fect on the independence or testability of the two of three low flow trip

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3.1 Evaluation. The removal of the RCP breaker auxiliary relays trip in the P-8 circuitry does not af fect the safety analyses, does not affect the independence or testability of the remaining signals, and does not affect any other reactor trips. Therefore, the proposal meets the guidelines of SRP 7.2.

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4.0 SUMMA RY

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The removal of the RCP breaker auxiliary relays trips to the P-8 cir-cuitry meets the guidelines of SRP 7.2, does not affect the safety analysis, and does not affect the operation of any other trips.

5.0 REFERENCES

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1. Final Safety Analysis Report, Beaver Valley Nuclear Station, Unit 1.

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2. Duquense Light letter (Dunn) to NRC (Varga) " Request for Ammendment ,

No. 46 to Operating License".

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3. Telcon S. Mays (EG&G) and R. Bruske (Duquense Light) of July 3,1980.

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