ML20137E219

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

ML20137E219
Person / Time
Site:	Hatch
Issue date:	12/23/1985
From:	Shum D Office of Nuclear Reactor Regulation
To:
Shared Package
ML20137E139	List: ML20137E134 ML20137E219
References
GL-83-28, NUDOCS 8601170200
Download: ML20137E219 (5)

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8,(jo uhogo UNITED STATES NUCLEAR REGULATORY COMMISSION

;y WASHINGTON, D. C. 20665 k * . . . . /'

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION GENERIC LETTER 83-28, ITEM 1.1 - POST-TRIP REVIEW GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MUNICIPAL ELECTRIC AUTHORITY OF GEORGIA CITY OF DALTON, GEORGIA EDWIN I. HATCH NUCLEAR PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-321 AND 50-366

1. 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 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 1 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 j low-low level. In this case, the reactor was tripped manually by the operator almost conincidentally with the automatic trip. On February 28, 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 NUREG-1000, " Generic Implications of ATWS Events i 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 l licensees of operating reactors, applicants for an operating license, and l

i holders of construction permits to respond to certain generic concerns. These concerns are categorized into the following four areas: (1) Post-Trip l 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 evaluation report addresses Action Item 1.1 only.

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4I. REVIEW GUIDELINES The following review guidelines were developed after the initial 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 guidelineseffectivelyripresenta"goodpractices"approachtopost-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 rast-trip review team has_ performed an analysis and determined 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 I

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 Cannittee (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 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 SRO Ifcense on the plant. The team leader should be charged with overall responsibility for directing the pdst-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 /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 equivalent organization.

l C. The licensee or applicant should indicate that the plant response to the ,

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

A verification 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 sequence of events to verify the proper functioning of safety related and other important equipment. Where

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possible, comparisons with previous similar events should be made.

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r-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 infomation 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 detemining 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 letters dated November 7,1983, and September 23, 1985, the licensee of Edwin I. Hatch Nuclear Plant, Units 1 and 2, 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, the licensee referred to the plant procedure, " Scram / Transient Reporting," which requires the following to be determined prior to the reactor being returned to power: the initial conditions, the cause, and 4

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, the sequence of the events during the scram / transient; the integrated system (including the reactor systems, the balance of plant systems, and safetysystems)responseduringtheevent;reportingrequirements;the need for near-tem corrective actions; and if there are unresolved safety concerns. We find that the licensee's restart criteria conform with the guidelines as described in the above 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 addressed the methods and criteria for comparing the event information with known or expected plant behavior. Based on our review, we find them to be acceptable.

D. The licensee has addressed the criteria for detemining the need for independent assessment of an event. 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 to the guidelines as described in j the above Sections II.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 j find that this program'is acceptable.

i j Based on our review, we conclude that the licensee's Post-Trip Review Program l and Procedures for Edwin I. Hatch Nuclear Plant. Units 1 and 2 are acceptable.

l l Principal Contributor: D. Shum

! Da* : December 23, 1985 j .

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