ML20138K075
| ML20138K075 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 12/12/1984 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20138K073 | List: |
| References | |
| GL-83-28, NUDOCS 8512180269 | |
| Download: ML20138K075 (5) | |
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Enclosure SAFETY EVALUATION FOR L
GENERIC LETIER 83-28, ITEM 1.1 - POST-TRIP REVIEW (PROGRAM DESCRIPTION AND PROCEDURE)
LACROSSE BOILING WATER REACTOR i
DOCKET NO.:
50-409 I.
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 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 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 at the Salem Nuclear Power Plant." As a result of this investigation, the Comi,ssion 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-TripReview.(2) Equipment Classification and Vendor Interface (3) Post-Maintenance Testing, and (4) Reactor Trip System Reliability Improvements.
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 addresses Action Item 1.1 only.
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II.- 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 incorpo-rate the best features of these submittals. Therefore, these review guidelines effectively re'present a " good practices" approach to post-trip review. The staff has 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.
The post-trip review team has determined the root cause and sequence of events resulting in the plant trip.
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Near ters corrective actions have been taken to remedy the cause of the trip.
i The post-trip review team has performed an analysis and determined that the major safety systems responded to the event within spec-ified limits of the primary system parameters.
The post-trip review has not resulted in the discovery of a poten-tial 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 indepen-b dent assessment of the event is performed by the Plant Operations f
Review Comittee (PORC), or another designated group 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 a senior operator 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 a Shift Technical Advisor
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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 e decision /recomendation 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 detemination made as to whether the plant response was within acceptable limits. The evaluation should l
include:
I A verification of the proper operation of plant systems and equip-ment by comparison of the pertinent data obtained during the l
j post-trip review to the applicable data provided in the FSAR.
!I ll An analysis of the sequence of events to verify the proper func-tioning 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:
I The criteria for determining the acceptability of restart
.The qualifications, responsibilities and authorities of key person-
~nel involved in the post-trip review process l
The methods and criteria for. determining whether the plant vari-ables and system respon5's 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 October 25, 1983 and ieptember 18, 1985, the licensee of Lacrosse Boiling Water Reactor provided information regarding its Post-Trip Review Program and Procedures. The staff has evaluated the licensee's program and procedure against the review guidelines developed as described in Section II.
A brief description of the licensee's response and the staff's evaluation of r
the response against each of the review guideline 1 is provided below:
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A.
The licensee has established criteria for htermining the acceptability of re, start from any unscheduled reactor trip. Based on our review we I
find that the licensee's criteria conform with the guidelines as t
described in 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 defined. The staff has reviewed the licensee's chain of comand 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 infongatJon.with known or expected plant behavior. Based on the review, the staff finds this to be acceptable.
D.
With regard to the criteria for determining the need for independent t
assessment of an event, the licensee,has indicated that if the cause of the event cannot be determined or postulated with any degree of assurance, an Operations Review Comittee meeting shall have been conducted prior to restart.
In addition, the licensee has established procedures to ensure that all physical evidence necessary for an independent assessment is preserved. The staff finds that these actions to be taken by the license conform to the guidelines as described in
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Sections II.A. and D, and are acceptable.
f E.
The licensee has provided for our review a systematic safety assessme program to assess unscheduled reactor trips. Based on the review, the staff finds that this. program is acceptabfe.
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Based' on the staff review, the staff concludes that the licensee's-Post-Trip l
Program and Procedures for Lacrosse Boiling Water Reactor are acceptable.
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