ML20247P176

Safety Evaluation Accepting Generic Ltr 83-28,Item 4.5.2 Re on-line Testing of Reactor Trip Sys

ML20247P176
Person / Time
Site:	Rancho Seco
Issue date:	05/30/1989
From:	NRC
To:
Shared Package
ML20247P163	List: ML20247P157 ML20247P176
References
GL-83-28, NUDOCS 8906060116
Download: ML20247P176 (2)

Text

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.j-UNITED STATES NUCLEAR REGULATORY COMMISSION

. WASHINGTON, D. C. 20555 T

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SAFETY EVALUATION. REPORT GENERIC-LETTER-83-28.1 TEM 4.5.2 REACTOR. TRIP. SYSTEM. RELIABILITY RANCHO.SECO DOCKET.NO. 50 312 0

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1.0 INTRODUCTION

.AWD.

SUMMARY

.On February 25, 1983., both of the scram circuit breakers at Unit 1.of the Salem Nuclear Power Plant failed to open upon an automatic reactor trip signal from the reactor protection system. This incident was terminated manually by the operator about 30 seconds after the initiation of the automatic trip signal. . The failure of the circuit breakers was determined to be related to

the sticking of the undervoltage trip-attachment. Prior,to this incident, on February 22, 1983, at Unit l'of the Salem Nuclear Power Plant, an' automatic trip signal was generateo based on steam generator low-low level during plant start-up. . In this- case, the reactor was tripped manually by the operator almost coincidence 11y with the automatic trip.

Following these incidents, on February 28, 1983, the NRC Executive Director for Operations (ED0), directed the staff to investigate and report on the generic implications of.these occurrences at Unit 1 of the Salem Nuclear Power Plant.

The results of the staff's inquiry into the generic implications of the Salem unit incidents'are reported in NUREG-1000, " Generic Implications of the ATWS Events at the Salem Nuclehr Power Plant." As a result of this investigation, Li the Commission (NRC) requested (by Generic Letter 83-28 dated July 8, 1983, 1 Ref. 1).all licensees of operating reactors, applicants fo!* an operating d license, and holders of construction permits to respond to generic issues j raised by the analyses of these two ATUS events. i i

This report is based on our contractor's evaluation (Ref. 3) of the response submitted by Sacramento Muncipal Utility District, the licensee for Rancho ,

Seco, for Item 4.5.2 of Generic Letter 83-28. The actual documents reviewed j as part of this evaluation are listed in the references at the end of the l report. j a

Item 4.5.2 requires licensees with plants not currently designed to permit 1 on-line testing to justify not making provisions for such testing. Alternatives  !

to on-line testing proposed by the licensees will be considered if the objectives  !

of high reliability can be met in another way. This review will:  ;

1. Confirm that the licensee has identified those portions of the  ;

Reactor Trip System (RTS) that are not on-line testable. If the entire RTS is verified to be on-line testable, with those exceptions addressed above, no further review is required.

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. 2. Evaluate modifications proposed by the licensee to permit on-line testing against the existing criteria for the design of the protection systems for the plant being modified.

3. Evaluate proposed alternatives to on-line testing of the RTS where the impracticality of the modifications necessary to permit on-line testing exists.

2.0 EVALUATION Sacramento Municipal Utility District (SMUD), the licensee for Rancho Seco, provided a response to Item 4.5.2 of the Generic Letter on November 4, 1983.

In that response, the licensee stated that SMUD performs, or has committed to make modifications to allow performance of, on-line testing of the RTS, in-cluding independent testing of the shunt and undervoltage trip attachments to the reactor trip breakers. Per a tele (S. Reynolds) and SMUD (J. Delezinski) phone on May 16,conversation between 1989, the licensee the NRC indicated that the necessary modifications were completed in 1986 and on-line testing of the RTS, including independent testing of the shunt and undervoltage trip attachments to the reactor trip breakers, is performed.

3.0 CONCLUSION

We find that the licensee's response, that they have the capability to perform on-line testing of the RTS, meets the Staff position on item 4.5.2 of the Generic Letter.

4.0 REFERENCES

1. NRC Letter, D. G. Eisenhut to all licensees of Operating Reactors, Appli-cants for Operating License, and Holders of Construction Permits, " Required Actions Based on Generic Implications of Salem ATWS Events (Generic Letter 83-28)," July 8, 1983.

2. Sacramento Municipal Utility District letter to NRC, R. J. Rodriquez to D. G. Eisenhut, Director, Division of Licensing, NRC, " Required Actions Based on the Generic Implications of Salem ATWS Events (Generic Letter 83-28)," November 4, 1983.

3. EGG-NTA-7462, " Technical Evaluation Report Reactor Trip System Reliability Conformance to Item 4.5.2 of Generic Letter 83-28 Arkansas Nuclear One-1, Crystal River-3, Davis-Besse-1, Oconee-1, -2, and -3, Rancho Seco, Three Mile Island-1, WNP-1," F. G. Farmer, Idaho National Engineering Laboratory, March, 1987.

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