ML20209J240

Safety Evaluation Supporting Util 831107 & 850816 Responses to Generic Ltr 83-28,Item 1.1, Post-Trip Review Program & Description

ML20209J240
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	11/05/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20209J228	List: ML20209J225 ML20209J240
References
GL-83-28, NUDOCS 8511110409
Download: ML20209J240 (4)

Text

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SAFETY EVAll'ATION BY THE OFFICE OF NUCLEAP REACTOR REGULATION FOR GENERIC LETTER 83-?8, ITEM 1.1 - POST-TRIP REVIEW (PROGRAM DESCRIPTION AND PROCEDURE)'

CONSUMERS POWER COMPANY BIG ROCK POINT PLANT .-

DOCKET NO. 50-155

1.0 INTRODUCTION

On February 25, 1983, both of the scram circuit breakers at Unit 1 of the Salem Nuclear Power Plant (SNPP) failed to open upon an autcmatic reactor trip signal from the reactor protection system. This incident occurred during plant start-up and the reactor was tripped manually by the cperator abcut 30 seconds after initiation of the automatic trip signal. Failure of the circuit breakers has been determined to be related to sticking of the urder voltage trip attachment. On February 22, 1983, an automatic trip occurred during the start-up of SNPP, Unit 1, as the result of steam generator low-low level. In this case, the reactor was tripped manually by the operator almost coincidentally with the automatic trip. On February 28, 1983, the NRC Executive Director for Operatfor.s directed the staff to investigate and report on the generic implicat1ons.of these occurrences. The results of this staff investigation are reported in NUREG.1000, " Generic Implications of ATHS Events at the Salem Nuclear Power Plant." As a 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 holders of construction permits to respond to certain generic concerns. These concerns are categorized into the following four areas: (1) Post-Trip Review, (2) Equipment Classification and Vendor Interface,(3) Post-Maintenance Testing, and (4) Rea:: tor Trip System Feliability Improvements, m

The first ection item, Post-Trip Review, consists of Action Item 1.1,

" Program Description and Procedure" and Action Item 1.2, " Data and Infomation Capability." This evaluation addresses Action Item 1.1 only.

, 2.0 PEVIEW GUIDELINES n

The following review guidelines were developed after initial evaluation of

-f En several utility responses to Item 1.1 of Gereric Letter 83-28 and incorporate the best features of these subrittals. Therefore, these review guidelines l

L@ effectively represent a " good practices" approach to post-trip review. We g have reviewed the licensee's response to Item 1.1 against these guidelines:

• O Q

a A. The licensee should have systematic safety assessment procedures established that will ensure that the following restart criteria are met before restart is authorized.

The post-trip review team has determined the rcot cause and sequence of events resulting in the plant trip.

t Near term corrective actions have been taken to remedy the cause of the trip.

The post-trip review team has performed an eralysis and determined that the ma,ior safety systems responded to the event within specified limits of the primary system parameters.

The post-trip review has not resulted in the discovery of a potential safety cencern (e.g., the root cause of the event occurs with a frequency significantly larger than expected).

If any of the above restart criteria are not met, then an independent assessment of the event is performed by the Plant Operations Review Committee (PORC), or another designated group with similar authority and experience.

B. The responsibilities and authorities of the personnel who will perform the review and analysis shculd be well defined.

The post-trip review team leader should be a rerber of plant marecerent at the shift supervisor level or above and should hold or should have held a Senior Operator license on the plant. The ,

team leader should be charged with overall responsibility for directirg the post-trip review, including data gathering and data assessment and he/she should have the necessary authority to obtain all personnel and data needed for the post-trip review.

A second person on the review team should be a Shift Technical Advisor (STA) or should hold a relevant engireering degree with special transient analysis training.

The team leader and the STA (rn gineer) should be responsible to concur on a decision /recommer : tion to restart the plant. A nonconcurrence fron either of these persons should be sufficient to prevent restart until the trip has been reviewed by the PORC or equivalent organization.

C. The licensee should indicate that the plant response to the trip event will be evaluated and a detemination made as to whether the plant response was within acceptable limits. The evaluation should include:

A verification of the proper opemtion of plant systems and equipment by comparison of the pertinent data obtained during the post-trip review to tte applicable data provided in the FSAR.

1 An analysis of the sequence of events to verify the proper  !

functioninn of safety related and other important equipment. Where  !

possible, comparisons with previous similar events should be made. '

5 D. The licensee should have procedures to ensure that all physical evidence necessary for an independent assessment is preserved.

E. Each licensee should provide in its submittal, copies of the plant procedures which contain the information required in Items A through D.

As a minimum, these should include the following:

The criteria for determining the acceptability of restart The qualifications, responsibilities and authorities of key personnel involved in the post-trip review process The methods and criteria for determining whether the plant variables and system responses were within the limits as described in the FSAR The criteria fer determining the need for an independent review.

3.0 EVALUATION AND CONCLUSION

, By letters dated November 7,1083, and August 15, 1985, the licensee of the Big Rock Point Plant provided information regarding its Post-Trip Review Program and Procedures. We have evaluated the licensee's program and procedures against the review cuidelines developed as described in Section 2.0. A brief description of the licensee's response and the staff's evaluation of the response against each of the review guidelines is provided below:

A. With regard to the criteria for determining the acceptability of restart, the licensee indicated that the Shift Supervisor will be required to file a Reactor Trip Report for any unscheduled reactor trip prior to the request for authorization to restart. The Reactor Trip Report will contain: a description of the initiating event; a verification that the reactor protection system and systems which are important to reactor safety have performed as required; and a verification of the cause of the trip and the adequacy of the subsequent corrective action taken. We find that the licensee's criteria for determining the acceptability of restart conform with the guidelines 4

described in Section 2.A and, therefore, are acceptable.

B. The qualifications, responsibilities and authorities of the personnel who will perform the review and analysis have been clearly defined. We have reviewed the licensee's chain of command for responsibility for post-trip review and evaluation, and find it acceptable.

C. The licensee has described the methods and criteria for comparing the event information with known or expected plant behavior. Based on our review, we find them acceptable.

6 D. With regard to the criteria for determining the need for independent assessment of an event, the licensee has indicated that if the cause of the trip cannot be determined, the Plant Peview Committee will perform a review of the situation and reccerend a course of action. In addition, the licensee has established procedures to ensure that all physical evidence necessary for an independent assessment is preserved. We find that these actions to be taken by the licensee conform with the guidelines described in Sections 2.A and D.

E. The licensee has provided for our review a systematic safety assessment program to assess unscheduled reactor trips. Based on our review, we find that this program is acceptable.

Based on our review, we conclude that the licensee's Post-Trip Peview Program and Procedures are acceptable for the Big Rock Point Plant.

4.0 ACKNOWLEDGEMENT This evaluation was prepared by D. Shum and T. Rotella.

Dated: November 5,1985 l

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