ML18092A807
| ML18092A807 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/12/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML18092A804 | List: |
| References | |
| GL-83-28, NUDOCS 8509230156 | |
| Download: ML18092A807 (6) | |
Text
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SAFETY EVALUATION REPORT FOR GENERIC LETTER 83-28, ITEM 1.1 - POST-TRIP REVIEW (PROGRAM DESCRIPTION AND PROCEDURE)
I.
INTRODUCTION SALEM GENERATING STATION. UNITS 1 AND 2 DOCKET NOS.:
50-272/311 On February 25 1 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 detennined to be related to the sticking of the under voltage trip attachment.
On February 22, 1983, during start-up of SNPP~ Unit l~ an automatic trip signal occurred 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.
Following these inc.idents, on February 28, 1983,. the NRC Executive Director for Operations (EDO) directed the staff to investigate and report on the
~eneric implications of these~occurrences. The results of the staff's inquiry into these incidents are reported in NUREG-1000, "Generic Implications of ATWS Events at the Salem Nuclear Power Plant." As a result of this investigation., the Co11111ission requested (by Generic Letter 83-28 dated July 8, 1983) all licensees of operating reactors, applicants for *an operating license, and holders of construction pennits to respond to certain generic concerns. These concerns are 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.
The first action item, Post-Trip Review, consists of Action Item 1.1, "Program Description and Proced~rc,n and Action !t~m 1.2, "Data and Infonnation *Capability." This safety evaluation report (SER) addresses Action Item 1.1 only *.
II.
REVIEW GUIDELINES The following review guidelines were developed after initial evaluation of the various utility responses to Item I.I of Generic Letter 83-28 and incorporate the best features of these submittals.
As such, these review guidelines in effect represent a 11good 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.
0 0
0 0
0 The post-trip review team has detennined the.root cause and sequence of events resulting in the plant trip.
Near tenn corrective actions have been taken to *remedy the cause of the trip.
The post-trip review team has performed an analysis and detennined 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 Operation~ Review Committee (PORC), or another designated group with similar authority and experience.
B.
The.r.esponsibilities and authorities of the personnel who will perform the review and analysis should be well defined.
0 0
0 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 license for 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/reco11111endation 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
- Ce 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:
0 0
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 possible, comparisons with previous similar events should be made.
- 0.
The.l~censee o~ 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 shou*ld include the following:
0 0
0 0
III.
The criteria for determining the acceptability of restart The qualifications, responsibilities and authorities of key personnel involved in the post-trip re~iew 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.
EVALUATION AND CONCLUSION By letters dated July-22, 1983, and August 2, 1985, the licensee of Salem Generating Station, 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 rev~ew guidelines 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 indicate~ that following an unscheduled reactor trip and prior to the request for authorization to restart, the Senior Shift Supervisor will be required to file a Post Reactor Trip/Safety Injection Report which will contain:
a description of the initiating
- eve~~; a verification that the reactor protection system and the engineered safety features and systems which are important to reactor safety have per't-Ormed 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 are acceptable.
B.
The qualifications, responsibilities and authorities of the personnel who will perfonn the review and analysis have been clearly described.
The licensee indicated that the Operations Manager, who bases his decision on the above cited restart.acceptability criteria, shall have the final authority to grant or deny authorization of plant restart.
We have reviewed the licensee's chain of colTITland for responsibility fo*r post-trip review and evaluation, and find it acceptable.
C.
The licensee has addressed the methods and criteria for comparing the event infonnation with known or-expected plant behavior.
Based on our review, we find them to be acceptable.
D.
With regard to the criteria for detennining the need for independent assessmen~ of an.event, the licensee indicated that the Nuclear Support Department wi 11 perfonn an independent review of each Reactor Trip/Safety Injection. In addition, the licensee indicated that if the cause of the trip cannot be positively detennined, or perfonnance of specified systems during the event is in question, an investigation of the event will be perfonned and the results will be reviewed by the Station Operations Review Committee.
We find that these actions to be taken by the licensee conform to the guidelines described in 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 find that this program is acceptable.
Based on our review, we conclude that the licensee's Post-Trip Review Program and Procedures.for Salem Generating Station, Units 1 and 2, are acceptable.