ML20134A578

Safety Evaluation Re Generic Ltr 83-28,Item 1.1, Post-Trip Review (Program Description & Procedure). Program & Procedures Acceptable

ML20134A578
Person / Time
Site:	Fort Calhoun
Issue date:	10/22/1985
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20134A571	List: ML20134A569 ML20134A578
References
GL-83-28, NUDOCS 8511070414
Download: ML20134A578 (5)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FURI CALFOUN STATION, UNIT 1 M sBLIC POWER DISTRICT , l GENERIC Lt11tR 83-78, ITEM I.1 - P051-TRIP REVIEW -

1 (PROGRAM DESCRIPTION AND PROCEDURE)

DOCKEI NO. 50-285 I. INTRODUCTION On February 25, 1983, both of the scram circuit breakers at Unit 1 of the SalemNuclearPowerPlant(SNPP)failedtoopenuponanautomaticreactor trip signal from the reactor protection system. This incident occurred during 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. On February 22, 1983, an automatic trip occurred during 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 23, 1983, the NRC Executive Director for Operations, directed the staff to investigate and report on the generic implications of these occurrences. The results of the staff's investigation are reported in huREG-1000. " Generic Implications of ATWS Events at the Salem Nuclear Power Plant." As a result of this investigation, the Connission requested (by l Generic Letter 43-28 dated July 8,1983) all Itcensees 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-TripReview.(2) Equipment Classification and Vendor Interface. (3) Post-Maintenance Testing, and (4) Reactor Trip System Reliability Improvements.

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The first action item. Post-Trip Review, consists of Action IMI.1

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

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J II. REVIEW GUIDELINES The foPowing review guidelines were developed after the inittai evaluation of several utility responses to item 1.1 of Generic Letter 83-28 and incorporate the best features of these submittals. Therefore, these review guidelines effectively represent a " good practices" approach to post-trip review. We have reviewed the licensee's response to Item 1.1 against these guidelines:

I 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, i

• The post-trip review team has detemined the root cause and ,

sequence of events resulting in the plant trip.

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

The post-trip review team has perfonned an analysis and determined

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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 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

?perations Review Comittee (PORC), or another designated group

with similar authority and experience. -

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8. The responsibilities and authorities of the personnel who will perform 4

the review and analysis should be well defined.

l 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.

f The team leader and the STA (Engineer) should be responsible to concur on a decision /recomendation to restart the plant. A l nonconcurrence from either of these persons should be sufficient to prevent restart until the trip has been reviewed by the PORC or l equivalent organization.

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

A verification of the proper operation of plant systems and i 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 sequence 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 independent 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 criterta for determining the need for an independent review.

III. EVALUATION AND CONCLUSION By letters dated November 4, 1983 and August 30, 1985, the licensee of Fort Calhoun, Unit 1, 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. With regard to the criteria for determining the acceptability of restart from any unscheduled reactor trip, the licensee indicated a post-trip

, review is conducted to identify the cause of the trip and the subsequent corrective action to be taken prior to plant restart. In addition, an analysis is conducted to verify that systems which are important

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i to reactor safety have performed as required. We find that the licensee's criteria for determining the acceptability of restart conform ,

with the guidelines described in Section II.A and, therefore, are acceptable.

B. The 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 th? methods and criteria for comparing the event information with known or expected plant behavior. Based on our review, we find them acceptable.

D. The licensee has described the criteria for determining the need for independent assessment of an event. Based on our review, we find that the actions taken by the licensee conform with the guidelines as described in the above Sections II.A and D.

E. The licensee has provided for our review a systematic safety assessment

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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 Program and Procedures are acceptable for Fort Calhoun Station, Unit 1.

1 Principal Contributor:

D. Shun 0

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