ML16152A491
| ML16152A491 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/11/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16152A490 | List: |
| References | |
| GL-83-28, NUDOCS 8510180517 | |
| Download: ML16152A491 (5) | |
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g UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE ON NUCLEAR REACTOR REGULATION GENERIC LETTER 83-28, ITEMS 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 AND 4.5.1 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3 DOCKET NOS. 50-269, 50-270 AND 50-287 I. INTRODUCTION In February 1983, the Salem Nuclear Power Station experienced two failures of the reactor trip system upon the receipt of trip signals.
These failures were attributed to Westinghouse - Type DB-50 reactor trip system (RTS) circuit breakers.
The failures at Salem on February 22 and 25, 1983, were believed to have been caused by a binding action within the undervoltage trip attachment (UVTA) located inside the breaker cubicle.
Due to problems with the circuit breakers at Salem and at other plants, NRC issued Generic Letter (GL) 83-28,"Required Actions Based on Generic Implications of Salem Anticipated Transient Without Scram (ATWS)
Events," dated July 8, 1983.
This letter required the licensees to respond to immediate-term actions to ensure reliability of the RTS.
Actions to be performed included development of programs to provide for post-trip review, classification of equipment, vendor interface, post-maintenance testing, and RTS reliability improve ments. The Generic Letter stated that for Action Items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1, and 4.5.1 NRC Regional Offices would perform a post-implementa tion review and issue Safety Evaluation Reports.
This report is the Regional Safety Evaluation of Duke Power Company submittals dated November 4, 1983,.August 10,
- 1984, February 21,
- 1985, March 20,
- 1985, March 29, 1985, and April 25, 1985, to GL 83-28 for Oconee Units 1, 2, and
- 3.
A regional inspection was conducted at the Oconee facility during July 29 - August 2, 1985, to review the licensee's current program, planned program improvements, and implementation of present procedures associated with post-trip review, equipment classification, vendor interface, post maintenance testing, and reactor trip system reliability.
The details of the inspection findings are discussed in Inspection Report No. 269, 270 and 287/85-21.
II. REVIEW GUIDELINES The licensee's responses were evaluated for compliance to the staff's positions delineated in GL 83-28 for Action Items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 and 4.5.1.
The requirements of the above action items, as described in the Generic Letter, are paraphrased below:
8510190517 851011 PDR ADOCK 05000269 P
2 3.1 Post-Maintenance Testing (Reactor Trip System Components)
Position
- 1. Licensees and applicants shall submit the results of their review of test and maintenance procedures and Technical Specificationsto assure that post-maintenance operability testing of safety-related components in the reactor trip system 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.
- 2. Licensees and applicants shall submit the results of their check of vendor and engineering recommendations to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications, where required.
3.2 Post-Maintenance (All Other Safety-Related Components)
Position The following actions are applicable to post-maintenance testing:
- 1.
Licensees and applicants shall submit a report documenting the extending of test and maintenance procedures and Technical Specifications 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.
- 2. Licensee and applicants shall submit t-he results of their check of vendor and engineering recommendations to ensure that any appropriate test guidance is included in the test and maintenance procedures or the Technical Specifications where required.
4.1 Reactor Trip System Reliability (Vendor-Related Modifications)
Position All vendor-recommended reactor trip breaker modifications shall be reviewed to verify that either:
(1) each modification has, in fact, been implemented; or (2) a written evaluation of the technical reasons for not implementing a modification exists.
For example, the modifications recommended by Westinghouse in NCD Elec-18 for the DB-50 breakers and a March 31, 1983, letter for the DS-416 breakers shall be implemented or a justification for not implementing shall be made available.
Modifications not previously made shall be incorporated or a written evaluation shall be provided.
3 4.5 Reactor Trip System Reliability (System Functional Testing)
Position On-line functional testing of the reactor trip system, including independent testing of the diverse trip features, shall be performed on all plants.
- 1.
The diverse trip features to be tested include the breaker undervoltage and shunt trip features on Westinghouse, B&W (see Action 4.3 of GL 83-28) and CE plants; the circuitry used for power interruption with the silicon controlled rectifiers on B&W plants (see Action 4.4 of GL 83-28); and the scram pilot valve and backup scram valves (including all initiating circuitry) on GE plants.
III. EVALUATION AND CONCLUSION By letters dated November 4, 1983, August 10, 1984, February 21,
- 1985, March 20, 1985, March 29, 1985 and April 25, 1985, Duke Power Company, (the licensee) provided information regarding their compliance to Sections 3.1, 3.2, 4.1, and 4.5 of GL 83-28.
We have evaluated the licensee's responses against the NRC positions described in Section II above for completeness and adequacy. We concluded that the licensee's responses to Action Items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 and 4.5.1 were acceptable and met the intent of GL 83-28.
Delineated below are the results of Region II's evaluation and a brief summary of the licensee's response:
A. Item 3.1.1, Review of Test and Maintenance Procedures and Technical Specifications (Reactor Trip System Components)
The licensee's response to this item is acceptable and meets the intent of GL 83-28. The licensee states in their submittal that Oconee has in place a program to assure that post-maintenance testing of all safety-related equipment is conducted and that such testing demonstrates that the equipment is capable of performing its safety functions.
The licensee further states, in their response that post maintenance operability testing is performed on the GE AK-2 breakers in the reactor trip system.
The breakers are periodically bench tested and a functional test is performed to verify that the breaker is capable of performing its safety functions.
The licensee also committed to review this action item with respect to the specific reactor trip system components list being developed by the generic B&W Owners Group.
We concur with the licensee's planned actions and request that the licensee submit a statement confirming that this action has been completed for the specific reactor trip system components list developed by the Generic B&W Owners Group.
4 B. Item 3.1.2, Check of Vendor and Engineering Recommendations for Testing and Maintenance (Reactor Trip System)
The licensee's submittal dated April 25, 1985, is the final response to action item 3.1.2. The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee states in this submittal that all requirements of Item 3.1.2 of Generic Letter 83-28 were fulfilled prior to March 31, 1985 for Oconee and that their investigation revealed no impact on Oconee's Technical Specifications.
C. Item 3.2.1, Review of Test and Maintenance Procedures and Technical Specifications (All Other Safety-Related Components)
The licensee's response to this item is acceptable and meets the intent of GL 83-28. The licensee states that a Station Directive exists which requires functional verification on all safety-related components following maintenance. In addition, another Station Directive provides guidelines for determining when a retest or functional verification is required. This Directive lists the components which require performance testing after replacement, repair, modification, and/or significant maintenance. It also provides administrative controls to ensure proper identification, scheduling, and performance of such required testing.
The licensee also states'that these procedures are periodically reviewed.
to assure conformance with existing requirements. The licensee considers that these procedures are effective in assuring that safety-related equipment is operable upon return to service.
D. Item 3.2.2, Check of Vendor and Engineering Recommendations for Testing and Maintenance (All Other Safety-Related Components)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee states in their response that they are implementing a substantial review to verify that all vendor instruction manuals are complete and consistent, and that the information in the vendor manuals is appropriately incorporated into plant procedures.
The licensee also states that administrative procedures have been established to control the distribution of vendor instruction manuals and to ensure that vendor guidance is appropriately incorporated into plant procedures. The licensee stated that the manual review program will involve comparing all in-house copies of vendor manuals. to ensure that all copies of a given manual are complete and consistent.
Region II verified that the manual review program was in-process and that the licensee had established an organization to perform and evaluate the review findings.
We concur with the licensee's actions and recommend that the licensee complete the above review and submit a statement confirming that item 3.2.2 has been implemented.
5 E. Item 4.1, Reactor Trip System Reliability (Vendor-Related Modifica tions)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee states in their response that they are participating in the B&W Owners Group effort to arrive at a long term solution to the RTB problem. The B&W Owners Group undertook a program to evaluate various possible modifications of the GE-AK-2 reactor trip breakers.
The results of this evaluation was the recommendation to change out the initial breaker lubricant to the Mobil 28 lubricant.
This recommendation is in accordance with GE Service Advice 9.20. The licensee states' that this recommendation has been completed on all breakers in service on Unit 1 and will be completed on Units 2 and 3 by the end of Unit 2 refueling outage in 1985. The licensee should confirm that this has been completed.
F. Item 4.5.1, Reactor Trip System Reliability (System Functional Testing)
The licensee's response to this item is acceptable and meets the intent of GL 83-28.
The licensee confirmed in their response that on-line functional surveillance testing is performed on the individual Reactor Protective System channels utilizing safety-related procedures.
This testing includes the diverse SCR trip feature which is tested once a month during on-line conditions.
The licensee also states that the diverse shunt trip and undervoltage trip features of the reactor trip breakers will be tested monthly to verify independent operability.
G. Conclusion Based on our reviews, we conclude that the licensee's responses to items 3.1.1, 3.1.2, 3.2.1, 3.2.2, 4.1 and 4.5.1.are acceptable and meet the full intent of GL 83-28. However, the licensee should complete their actions in regard to items 3.1.1 and 3.2.2 and 4.1 and submit a statement confirming these actions have been implemented.
Dated:
October 11, 1985 Principal Contributor:: T. E. Conlon