ML20206L951
| ML20206L951 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 08/12/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20206L882 | List: |
| References | |
| GL-83-28, NUDOCS 8608200416 | |
| Download: ML20206L951 (5) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO GENERIC LETTER 83-28, ITEMS 3.1.1, 3.1.2, 3.2.1, 3.2.2 AND 4.5.1 BOSTON EDISON COMPANY PILGRIM NUCLEAR POWER STATION DOCKET NO. 50-293 1.0 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 startup, 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 undervoltage trip attachment.
Prior to this incident, on February 22, 1983, at Unit 1 of the Salem Nuclear Power Plant, an auto-matic trip signal was generated due to a steam generator low-low level during plant startup.
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 (EDO), 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 incidents are reported in NUREG-1000,
" Generic Implications of ATWS Events at the Salem Nuclear Power Plant."
i As a result of this investigation, the Director, Division of Licensing, i
Office of Nuclear Reactor Regulation requested (by Generic Letter 83-28 i
dated July 8,1983) all licensees of operating reactors, applicants for an operating license, and holders of construction permits to respond to cer-tain generic concerns.
These concerns are categorized into four areas:
(1) Post-Trip Review, (2) Eoulpment Classification and Vendor Interface, (3) Post-Maintenance Testing, and (4) Reactor Trip System (RTS) Reliability I
Improvements. Within each of these areas, various specific actions were i
delineated.
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-j This safety evaluation (SE) addresses the following actions of Generic Letter 83-28:
3.1.1 and 3.1.2, Post Maintenance Testing (Reactor Trip System Components) l 3.2.1 and 3.2.2, Post Maintenance Testing (All Other Safety-Related l
Components) i 4.5.1, Reactor Trip System Reliability (System Functional Testing) i 1
8600200416 860812 PDR ADOCK 05000293 P
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Safety Evaluation 2
By letters dated November 7, 1983, December 30,1983, June 28,1984, October 4, 1984, and April 25, 1986, Boston Edison Company (BEco-Licensee) described their planned and completed actions regarding the above items for the Pilgrim Nuclear Power Station.
2.0 Evaluation 2.1 General Generic Letter 83-28 included various NRC staff positions regarding the specific actions to be taken by operating reactor licensees and operating license applicants. The Generic Letter 83-28 positions and discussions of licensee compliance regarding Actions 3.1.1, 3.1.2, 3.2.1, 3.2.2 and 4.5.1 for Pilgrim are presented in the sections that follow.
2.2 Actions 3.1.1 and 3.1.2, Post-Maintenance Testing (Reactor Trip System Components)
Position Licensees and applicants shall submit the results of their review of test and maintenance procedures and Technical Specifications to assure that post-maintenance operability testing of safety-related components in the reactor trip system (RTS) is required to be con-ducted and that the testing demonstrates that the equipment is capable of performing its safety functions before being returned to service.
Licensees and applicants shall submit the results of their check of vendor and engineering recommendations (regarding safety-related components in the RTS) to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications, where required.
Discussion By letters dated November 7, 1983 and April 25, 1986 the licensee i
stated that station procedures and Technical Specifications were reviewed for safety-related systems, structures, and components (SS&C),
and that post-maintenance testing of safety-related components in the I
reactor trip system is required to be performed in accordance with station procedure 1.5.3, Maintenance Requests, and is tracked by the Maintenance Request (MR) form.
The review of SS&Cs was completed and validation of the results was made through an independent review by engineering, operations, maintenance and QA.
The licensee also instituted a Procedure Update Program (PUP) for maintenance proced-ures as a part of a performance improvement plan. The licensee fur-ther stated that revisions or additions to post-maintenance programs or procedures would be implemented in an ongoing, timely manner, I
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l Safety Evaluation 3
pending final recommendations by the BWR owner's group and a Nuclear Utility Task Action Committee (NUTAC), as well as other vendors.
In a letter dated April 25, 1986, the licensee clarified the responsibil-ities of the site personnel in determining the post work maintenance and operability tests.
Based on the above, the staff concluded that the licensee has complied with positions for actions 3.1.1 and 3.1.2 of Generic Letter 83-28.
2.3 Actions 3.2.1 and 3.2.2, Post-Maintenance Testing (All Other Safety Related Components)
Position Licensees and applicants shall submit a report documenting the ex-tending of test and maintenance procedures and Technical Specifica-tions review to assure that post-maintenance operability testing of all safety-related equipment is required to be conducted and that the testing demonstrates that the equipment is capable of performing its safety functions before being returned to service.
Licensees and applicants shall submit the results of their check of vendor and engineering recommendations (all other safety-related components) to assure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifica-tions, where required.
Discussion In letters dated November 7, 1983, and April 25, 1986, the licensee stated that the post-maintenance testing of the safety-related com-ponents was required by Station Procedure 1.5.3, Maintenance Requests.
The specific test and procedure / method to do the required post-main-tenance testing are determined by both the maintenance engineer and operating supervisor.
The complete review of the safety-related SS&Cs was completed and the review results were validated by Operations, Maintenance, Engineering, and Quality Assurance.
The licensee further indicated that a review of maintenance procedures was completed and a Procedure Update Program (PUP) was instituted as part of the performance improvement effort for maintenance procedures. The PUP, a one time effort, has been completed including the vendor manual validation, and subsequent additional procedural revisions will be handled by existing organizational procedures. The licensee also stated that surveillance frequencies in Technical Specifications for the safety-related systems were initially formulated using vendor information and established probability techniques, and that vendor or other recommendations would be updated and incorporated into procedures as operating experience and new information are developed.
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The licensee is further considering an evaluation of relevant industry and station failure data to assess appropriate actions concerning post-maintenance testing requirements, and stated that the results of the BWR Owner's Group and GE's recommendations and results would be incorporated into the programs.
Based on the above and the licensee's commitment to incorporate future vendor recommendations into a maintenance procedure, the staff concluded that the licensee has complied with the NRC staff position for action 3.2.1 and 3.2.2 for Generic Letter 83-28.
2.4 Action 4.5.1, Reactor Trip System Reliability (System Functional Testing)
Position On-line functional testing of the reactor trip system, including in-dependent testing of the diverse trip features, shall be performed on all plants. The diverse trip features to be tested include the breaker undervoltage and shunt trip features on Westinghouse, B&W and CE plants; the circuitry used for power interruption witn the silicon controlled rectifiers on B&W plants; and the scram pilot valve and backup scram valves (including all initiating circuitry) on GE plants.
Discussion In a letter dated November 7, 1983, the licensee indicated that on-line functional testing of the reactor protection system, and inde-pendent testing of the diverse trip features were performed in accord-ance with appropriate Technical Specification requirements, which included initiating circuitry, logic checks, and the actuating device.
In a letter. dated June 28, 1984, the licensee further stated that a specific surveillance test for the backup scram valves was not performed routinely. The licensee has explained, and the staff agrees, that the reactor trip system currently is not designed to permit periodic on-line functional testing of backup scram valves.
Justification for not making modifications to permit on-line testing has been reviewed separately by the staff under Action Item 4.5.2 of Generic Letter 83-28.
The staff found that such modifications are not required.
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Safety Evaluation 5
I Based on the above, the staff concluded that the licensee has complied with the NRC staff position for Action 4.5.1 of Generic Letter 83-28.
3.0' Conclusion The staff concludes that the licensee has complied with Actions 3.1.1, 3.1.2, 3.2.1, 3.2.2, and 4.5.1 of Generic Letter 83-28.
Dated: August 12, 1986 I
i Principal Contributor:
i J. Chung, Division of Reactor Safety, Region I
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