ML20127E105

Safety Evaluation Re Util 831104 Response to Generic Ltr 83-28,Item 1.1 Concerning post-trip Review Program & Procedure

ML20127E105
Person / Time
Site:	Cooper
Issue date:	05/06/1985
From:	Office of Nuclear Reactor Regulation
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Shared Package
ML20127E103	List: ML20127E099 ML20127E105
References
GL-83-28, NUDOCS 8505170361
Download: ML20127E105 (6)

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+.,....*p SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGUfATION GENERIC LETTER 83-28, ITEM 1.1 POST TRIP REVIEW PROGRAM AND PROCEDURE COOPER NUCLEAR STATION DOCKET NO. 50-298 I. INTRODUCTION 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 occurred during the plant start-up 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 Power Plant, an automatic trip signal was generated based on steam generator low-low level during plant start-up. 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 (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 ATWS Events at the Salem

! Nuclear Power Plant." As a result of this investigation, the Commission (NRC) 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 art 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.

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

" Program Description and Procedure" and Action Item 1.2. " Data and Information Capability." This safety evaluation report (SER) addresses l Action item 1.1 only. 8505170361 850506 PDR ADOCK 05000298 p PDR

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II. REVIEW GUIDELINES The following review guidelines were developed after initial evaluation of the various utility responses to Item 1.1 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 post-trip review. We have reviewed the licensee's response to Item 1.1 against these guidelines:

A. The licensee or applicant 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 root cause and sequence of events resulting in the plant trip.

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

The post-trip review team has performed an analysis and detennined ~

r that the major 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 concern (e.g., the root cause of the event occurs l 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 Comittee (PORC), or another designated group l with similar authority and experience.

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

The post-trip review team leader should be a member of plant management at the shift supervisor level or above and should hold or should have held an SR0 license on the plant. The team leader should be charged with overall responsibility for directing 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 an STA or should hold a relevant engineering degree with special transient analysis training.

The team leader and the STA (Engineer) should be responsible to concur on a decision / recommendation to restart the plant. A nonconcurrence from 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 or applicant should indicate that the plant response to the trip event will be evaluated and a determination made as to whether the plant response was within acceptable limits. The evaluation should include:

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

An analysis of the secuence of events to verify the proper functioning of safety related and other important equipment. Where possible, comparisons with previous similar events should be made.

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D. The licensee or applicant should have procedures to ensure that all

_ physical evidence necessary for an indepenccat assessment is preserved.

E.. Each licensee or applicant 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 for determining the need for an independent review.

'III. EVALUATION.AND CONCLUSION By letter dated November 4,1983, the licensee of Cooper Nuclear Station provided information regarding its Post-Trip Review Program and Procedures.

We have evaluated the licensee's program and procedures against the. review guidelines developed as described in Section II. 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. The licensee has established the criteria for determining the acceptability of restart. We find that the licensee's criteria conform ,

to the guidelines as described in'the above Section II.A and, therefore, are acceptable.

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B. The qualifications, responsibilities and authorities of the personnel who will perform the review and analysis have been clearly described.

4 We have reviewed the licensee's chain of command for responsibility for post-trip review and evaluation, and find it acceptable, i

C. With regard to the methods and criteria for comparing the event

.information with known or expected plant behavior, the licensee indicated that during the post-trip review, the reactor engineering staff will review performance of systems with respect to plant Technical Specifications. Based on our review, we find this action taken by the licensee to be acceptable.

D. With regard to the criteria for determining the need for independent assessment of an event, the licensee has indicated that the Plant Engineering Department will be requested to conduct an independent review of the trip. In addition, a group composed of the Station Operating Review Committee plus other personnel needed to provide the necessary technical expertise will review the sequence of events and confirm the cause of the trip. They also verify the corrective actions taken and that no other abnormalities were observed. Also, the licensee has established procedures to ensure that all physical evidence necessary for an independent assessment. is preserved.. We find that

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these actions to be taken by the licensee conform to the guidelines as described in the above Sections II.C. and D.

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i 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 Review Prograin and Procedures for Cooper Nuclear Station, are acceptable.

Principal Contributor: -D. Shum Dated:

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