ML20209A700

Safety Evaluation Accepting Util Response to Vendor Recommended Reliability Verification Testing Per Generic Ltr 83-28,Item 4.5.1 Re Reactor Trip Sys Reliability (Sys Functional Testing)

ML20209A700
Person / Time
Site:	Cooper
Issue date:	01/30/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20209A684	List: ML20209A680 ML20209A700
References
GL-83-28, NUDOCS 8702030418
Download: ML20209A700 (2)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION GENERIC LETTER 83-28 ITEM 4.5.1 - REACTOR TRIP SYSTEM RELIABILITY (SYSTEM FUNCTIONAL TESTING)

COOPER NUCLEAR STATION DOCKET N0: 50-298 I. INTRODUCTION On February 25, 1983, both 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 occurred during the plant startup and the reactor was tripped manually by the operator-about 30 seconds after the initiation of the automatic trip signal. The failure of the circuit breakers has been determined to be related to the sticking of the under voltage trip attachment. Prior to this incident, on February 22, 1983, at Unit 1 of the Salem Nuclear Plant, an automatic trip signal was generated based on steam generator low-low level during plant startup. In this case, the reactor was tripped manually by the operator almost coincidentally with the automatic trip. Following these incidents, on February 28, 1983, the NRC Executive Director for Operations, directed the staff to investigate and report on the generic implications of these occurrences at Unit 1 of 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 ATWS Events at the l Salem Nuclear Power Plant." As as result of this investigation, the Commission requested (by Generic Letter 83-28 dated July 8, 1983) all

, licensees of operating reactors, applicants for an operating license, and i

holders of construction permits to respond to certain generic concerns.

These concerns are categorized into four areas: (1) Post Trip Review, (2)

Equipment Classification and Vendor Interface, (3) Post-Maintenance Testing, and (4) Reactor Trip System Reliability Improvements.

The fourth action item, Reactor Trip System Reliability Improvements consists of Action Items 4.1 through 4.5. This safety evaluation addresses Action Item 4.5.1, RTS Reliability Improvements (System Functional Testing) only.

II. REVIEW GUIDELINES The following review guidelines were developed after initial evaluation of the various utility responses to item 4.5.1 of Generic Letter 83-28 and incorporate the best features of these submittals. As such, these review guidelines in effect represent a " good practices" approach to RTS reliability verification review. We have reviewed the licensee's response to items 4.5.1 against these guidelines:

The licensee has submitted a statement committing to independent, on-line functional testing of the diverse trip features.

8702030418 870130 PDR ADOCK 05000298 P PDR

r III. EVALUATION AND CONCLUSION By letter dated November 4,1983, the licensee of Cooper Nuclear Station provided information regarding RTS on-line testing of diverse trip features. We have reviewed the licensee's response against the review guidelines as described in Section II. A brief description of the

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licensee's response and the staff's evaluation of the response against the review guidelines is provided below:

The licensee stated that the reactor protection system and the control rod drive components test all the diverse trip features utilizing five separate tests. Each of the above tests are on-line functional tests. Our letter dated April 23, 1985, " Request for Additional Information Following Preliminary Staff Review of Licensee Responses to Generic Letter 83-28," from D. B. Vassallo to J.

M. Pflant, speaks to the acceptance, by NRC, of the backup scram -

valves being tested during refueling shut downs; hence, the staff finds the licensee's answer acceptable.

Based on our review, we conclude that the licensee's responses to vendor recommended reliability verification testing for Cooper Nuclear Station is acceptable.

Principal NRC contributor: G. Pick Dated: January 30, 1987 m