IR 05000271/1993009
| ML20046C733 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 08/02/1993 |
| From: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Reid D VERMONT YANKEE NUCLEAR POWER CORP. |
| Shared Package | |
| ML20046C734 | List: |
| References | |
| EA-93-112, NUDOCS 9308120025 | |
| Download: ML20046C733 (5) | |
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UNITED STATES
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KING OF PRUS$1A, PENNSYLVANIA 19804 141s
- * $ocket No. 50-271 August 2, 1993 I
License No. DPR-28 EA 93-112 I
Mr. Donald Vice President - Operations Vermont Yankee Nuclear Power Corporation RD 5, Box 169 Ferry Road Brattleboro, Vermont 05301
Dear Mr. Reid:
SUBJECT:
NOTICE OF VIOLATION.AND PROPOSED IMPOSITION OF CIVIL PENALTY - $50,000 Inspection Report No. 50-271/93-09 This refers to the safety inspection conducted at the Vermont Yankee Nuclear Power Plant,
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Vernon, Vermont, on April 14-16, 1993, and completed in the NRC Region I office on May 11,1993. The inspection was conducted to review the circumstances associated with a failure to properly evaluate test data, the failure to take corrective actions for a condition adverse to quality, and the earlier occurrence of a violation of the plant Technical Specifications (TS)
for which the plant was not shut down as required. The inspection report was transmitted to you on May 21.1993. On June 15, 1993, an enforcement conference was held in the Region I office with you and other members of your staff to discuss the potential violations, their causes:
and your corrective actions.
On October 15,1992, a surveillance test was performed to verify that control rod average scram response times met the limits set forth in the TS. During that test, your staff found that although the average scram response time for the entire core met all appropriate scram response time limits, the average scram response time to Notch 46 (5% insertion) for the three fastest control rods of one of the two-by-two control rod arrays exceeded the TS limit by.012 seconds. Your staff erroneously concluded, based on a review of the test results, that the two-by-two array average scram time was outside the scope of the TS requirements because (1) the two-by-two scram time requirements were not addressed in the TS bases and were not part of the plant safety analysis assumptions, and (2) the Standard Technical Specifications for similar plants do not require the same actions. As a result of this erroneous conclusion,' the reactor was not shut down, as required by the TS. Although a subsequent retest of the two-by-two array ;was satisfactory, it should not have been relied upon to demonstrate compliance with the TS. In this.
case, the potential safety consequences of the increased scram insertion time were minimal because the ability of the control rods to protect against fuel damage was not affected..
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Nevertheless, the NRC is concerned that no immediate actions were taken to identify the root causes of the deficiency and pursue corrective actions, and no reports were made to the NRC.
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CERTIFIED MAIL RETURN RECEIPT REOUESTED u
9308120025 930802 PDR ADOCK 05000271
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Vermont Yankee Nuclear Power
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Corporation On April 6,1993, another scram response time surveillance test was performed. On this occasion, the average scram response time for seven two-by-two arrays, as well as the core wide average, exceeded the TS limits for insertion to Notch 46. Following the testing, you requested that the NRC exercise enforcement discretion and not require a reactor shutdown since your safety analysis concluded that the average insenion time limits to Notch 46 could be increased to 0.500 seconds without impacting the ability of the control rods to protect against fuel damage, and all of the out-of-specification scram times identified during the October 1992 and April 1993 tests were within 0.500 seconds. Although the NRC exercised discretion for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, the NRC required that the root causes of the increased scram response time be identified before considering any further request for extension of the discretion.
Subsequently, there was no request for extension of the discretion because on April 7,1993, the plant was shut down due to an unrelated concern.
Your subsequent investigation into the control rod problem revealed that degraded elastomer components in the ASCO scram pilot valves were the root cause of the increased scram times.
In addition, you determined that procedural weaknesses allowing the acceptance of retest results to satisfy TS requirements, an inadequate scram time trending program, and inherent errors in test recorders, were contributing causes for your failure to identify the increased scram insertion times sooner.
The violations associated with the above failures are described in the enclosed Notice of Violation and Proposed Imposition of Civil Penalty (Notice) (Enclosure). The 5tst violation involved your failure to evaluate adequately the October 1992 test results to assure that test requirements had been satisfied. The second violation involved your failure to determine the root causes of the October 1992 test deficiency and take appropriate corrective actions to prevent recurrence. The third violation involved the failure to shut down the reactor in October 1992, as required by the TS, when the average insertion time of a two-by-two control rod array exceeded the TS limit. This deficiency was identified by you on April 6,1993, and was reported to the NRC on that same day when the additional control rod scram insertion times were exceeded.
The NRC is concerned that although you recognized, after the October 1992 event, that the scram insertion times were showing an increasing trend, you did not adequately pursue the root causes of this increase until questioned by the NRC in April 1993. Your evaluation of the October test results was inadequate and indicates that your staff did not adequately compare the results with plant TS requirements. Notwithstanding the low potential safety consequences of the actual degradation in control rod insertion times, the incidents constitute a significant regulatory coan because of the programmatic weaknesses that resulted in these violations, as well as the fact that, the worsening condition would have continued to exist if the NTC did not raise questions in April 1993. Therefore, in accordance with the, " General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy) 10 CFR Part 2, Appendix C, these violations are classified in the aggregate as a Severity Level III problem.
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Vennont Yankee Nuclea Power
Corporation The NRC recognizes that after the April 6th event, immediate actions were taken to correct the violations and prevent recurrence. Three task teams were formed to evaluate the scram time deficiency and the associated failure to comply with the TS. All scram pilot valves were replaced and the scram insertion times were tested and found to be within the TS limits prior to plant restart. In ad.iition, the practice of using retest data for scram time TS compliance has been discontinued. Further, a memorandum was issued by the Plant Manager which highlighted the problems in the management system that allowed the TS violation to occur, and also required an evaluation of TS and surveillance test practices to ensure that margin to TS limits is monitored and maintained, and that corrective actions and management notificatic:.s are made in a timely manner. As a long-term corrective action, an enhanced trending program for scram i
times and indicators for predictive maintenance are being developed.
Notwithstanding these actions, to emphasize the importance of timely and a jequate evaluation of operational and test data, proper comparison of that data to regulatory requirements and prompt determination of the root causes of test discrepancies so that corrective measures can be i@mented, I have been authorized, after consultation with the Director, Office of En:orcement, and the Deputy Executive Director for Nuclear Reactor Regulation, Regional Operation and Research, to issue the enclosed Notice of Violation and Proposed Imposition of Civil Penalty (Notice) in the amount of $50,000 for the Severity Level III problem.
The base value of a civil penalty for a Severity Level III problem is $50,000. The escalation
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and mitigation factors set forth in the Enforcement Policy were considered. The base civil penalty was mitigated 50% because of your prompt and comprehensive corrective actions once the TS violation was identified in April 1993. However, the base civil penalty was escalated
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509 because of the decline in performance in areas specifically related to the violations as evidenced by declines in the SALP ratings of the areas of Engineering / Technical Support and
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Safety Assessment! Quality Verifications during the last SALP assessment. Additionally, such escalation is supported by your declining overall performance as evidenced by a Severity Level III violation without a civil penalty on January 10,1992 and a $75,000 civil penalty issued on August 14. 1991. The other adjustment factors in the Policy were considered and no further adjustment to the base civil penalty was considered appropriate. On balance, no adjustment to the base civil penalty resulted from thc application of the escalation and mitigation factors.
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Since you erroneously concluded that average scram insertion time for the two-by-two array was outside the scope of the TS, this violation was not reported to the NRC as required. A violation for that failure to report could be issued. However, the NRC has decided not to issue a citation for that violation since your staff's failure to recognize that the condition constituted a TS violation directly contributed to your failure to report it to the NRC. The NRC is exercising its discretion on this reporting issue because (1) once the October 1992 violation was identified in April 1993, it was reported and (2) such a citation would not result in any corrective actions beyond those for your staff's failure to recognize that the plant was operated in violation of the
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TS.
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Verinont Yankee Nuclear Power
Corporation You are required to respond to this letter and should follow the instructions specified in the enclosed Notice when preparing your response. In your response, you should document the specific actions taken and any additional actions you plan to prevent recurrence. After reviewing your response to this Notice, including your proposed corrective actions and the results of future inspections, the NRC will determine whether further NRC enforcement action is necessary to ensure compliance with NRC regulatory requirements.
In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter and its enclosure will be placed in the NRC Public Document Room.
The responses directed by this letter and the enclosed Notice are not subject to the clearance procedures of the Office of Management and Budget as required by the Paperwork Reduction Act of 1980. Pub. L. No.96-511.
Sincerely, v
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Thomas T. Martin Regional Administrator Enclosure: Notice of Violation and Proposed Imposition of Civil Penalty
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Vermont Yankee Nuclear Power
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cc w/ encl:
R. Wanczyk, Plant Manager J. Thayer, Vice President, Yankee Atomic Electric Company L. Tremblay, Senior Licensing Engineer, Yankee Atomic Electric Company J. Gilroy, Director, Vermont Public Interest Research Group, Inc.
D. Tefft, Administrator, Bureau of Radiological Health, State of New Hampshire R. Gad, Esquire
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G. Bisbee, Esquire R. Sedano, Vermont Department of Public Service
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T. Rapone, Massachusetts Executive Office of Public Safety Chief, Safety Unit, Office of the Attorney General, Commonwealth of Massachusetts Public Document Room (PDR)
Local Public Document Room (LPDR)
Nuclear Safety Information Center (NSIC)
K. Abraham, PAO-R1 (2)
NRC Resident Inspector State of New Hampshire, SLO Designee State of Vermont, SLO Designee Commonwealth of Massachusetts, SLO Designee
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