EA-96-210 - Vermont Yankee (Vermont Yankee Nuclear Power Corp.)
Mr. Ross Barkhurst
President and CEO
Vermont Yankee Nuclear Power Corporation
RD 5, Box 169
Brattleboro, Vermont 05301
SUBJECT: NOTICE OF VIOLATION AND PROPOSED IMPOSITION OF CIVIL PENALTY - $50,000 (NRC Inspection Report No. 50-271/96-07)
Dear Mr. Barkhurst:
This letter refers to the NRC special inspection conducted from June 3 through June 14, 1996, at the Vermont Yankee Nuclear Power Station. The purpose of this inspection was to review the circumstances surrounding your staff's identification, on April 11, 1996, of a single failure vulnerability of the residual heat removal (RHR) system. This single failure vulnerability existed because of the potential for the minimum flow valve in each train not opening, as needed, to ensure that the pumps were not "dead-headed" if reactor system pressure exceeded the pump head. The inspection report was sent to you on July 2, 1996. Based on the inspection, two apparent violations of NRC requirements were identified, as described in the inspection report. On July 23, 1996, a predecisional enforcement conference was conducted with you and members of your staff to discuss the apparent violations identified during the inspection, their causes, and your corrective actions.
Based on our review of the inspection findings, your related Licensee Event Report (LER) No. 96-010, dated May 9, 1996, and information provided during the conference, one violation is being cited and is described in the enclosed Notice of Violation and Proposed Imposition of Civil Penalty (Notice). The violation involves the failure to include an analysis of the most damaging single failure vulnerability for certain loss of coolant accidents (LOCAs) in the analysis of possible failure modes of Emergency Core Cooling System (ECCS) equipment and the effects of those failure modes on ECCS performance. Specifically, the analyses performed for each operating cycle since 1974, pursuant to 10 CFR Part 50, Appendix K, including the most recent Cycle 16, 17, and 18 analyses conducted in the past five years, did not consider a specific single failure vulnerability that existed for certain LOCAs. The condition involved intermediate and small break LOCAs in which the four RHR pumps (two per train) would receive a signal to start but would not be able to inject water to the vessel because reactor pressure would be greater than the pump's discharge pressure. In those cases, the possibility existed for damage to the RHR pumps because the motor-operated minimum flow valves (one per train) were normally closed, and if there was a failure of the related Emergency Diesel Generator (EDG), the valves would not automatically open and permit recirculation flow to provide pump cooling. The condition existed since 1974 when a design change was implemented that resulted in cross powering the two RHR pumps in each train from separate EDGs (the minimum flow valve for that particular train was also powered from one of the two station EDGs). As a result, a loss of a single EDG that powered the minimum flow valve for a particular train would disable not only the RHR pump powered by the inoperable EDG, but also could result in damage to the RHR pump powered by the other operable EDG because of the inability to open the minimum flow valve and establish pump cooling. The failure to consider this condition during the various analyses constitutes the violation of 10 CFR Part 50, Appendix K.
The NRC recognizes and commends your Appendix R Project Team that identified this single failure vulnerability in April 1996, as part of its Appendix R review. Nonetheless, the NRC is concerned that this condition existed for 22 years without being identified during any of the Cycle analyses, even though a number of plant and industry operating events and activities related to the RHR system had been reviewed and evaluated by your staff, as you acknowledged at the enforcement conference, and these reviews and evaluations should have resulted in the identification and correction of this problem much sooner. These opportunities included during: (1) the formulation of corrective actions to address a similar single failure vulnerability affecting the RHR Service Water Heat Exchanger outlet valves that was identified in July 1989 and documented in LER 89-09; (2) the design review activities involving the development of the Individual Plant Evaluation in December 1993, that correctly modeled this single failure issue, but failed to identify the vulnerability; (3) the June 1993, LOCA Reanalysis conducted by your staff for Cycle 17 operation that did not revalidate the previous LOCA analysis assumptions; and (4) the review of Revision 48, dated January 4, 1995, to Piping and Instrument Diagram (P&ID) G-191172, which was a Corrective Update to revise the P&ID to specifically indicate that the RHR minimum flow valves (V10-16A and V10-16B) were normally closed (although the valve position had been changed in 1971 during construction from "normally open" to "normally closed" because of concerns about a draindown of the reactor to the suppression pool, the P&ID had never been updated to reflect that change). In each case, the reviews were apparently too narrowly focused and/or insufficient in scope or depth to identify the vulnerability. Given the significance of this finding, the violation has been categorized at Severity Level III, in accordance with the "General Statement of Policy and Procedure for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600.
In accordance with the Enforcement Policy, a base civil penalty in the amount of $50,000 is considered for a Severity Level III violation. Your facility has been the subject of escalated enforcement actions within the last 2 years<1>, therefore, the NRC considered whether credit was warranted for Identification and Corrective Action in accordance with the civil penalty assessment process in Section VI.B.2 of the Enforcement Policy. Credit is warranted for Identification because you identified the violation. Credit also is warranted for Corrective Actions because your corrective actions, once the violation was identified, were considered prompt and comprehensive. These actions, which were discussed during your presentation at the conference, include, but are not limited to: (1) performance of an engineering evaluation to assess the significance of the issue; (2) performance of a 10 CFR 50.59 analysis to support repositioning the RHR minimum flow valves to "normally open" so as to allow minimum flow even in the event of a loss of the related EDG; (3) review of all plant programs to ensure that the correct position of the RHR minimum flow valves was reflected in each program; (4) examination of all ECCS for susceptibility to a single failure vulnerability; (5) update of the RHR system plant engineering drawings and UFSAR description regarding the minimum flow valve position and the LOCA analysis scenario; (6) review of the design change process to determine if any weaknesses remain that could result in similar problems with plant engineering drawings, specifications, and operating procedures; and (7) conduct of engineering staff training regarding the need for comprehensive, rather than narrowly focused, reviews of operating experience reports.
Since credit is warranted for both identification and corrective actions, a civil penalty would not normally be issued in accordance with the civil penalty assessment process set forth in the Enforcement Policy. However, given the length of time (approximately 22 years) that this condition existed, as well as the number of prior opportunities that existed to identify and correct this violation sooner, I have been authorized, after consultation with the Director, Office of Enforcement, to exercise enforcement discretion in accordance with Section VII.A.1 of the Enforcement Policy and issue the enclosed Notice that assesses a civil penalty at the base amount of $50,000.
The second apparent violation identified in the inspection report, involving the failure to take corrective action for particular aspects of the RHR system single failure vulnerability has been factored into the enclosed Notice and discussed in the description of missed opportunities that existed to identify the violation of Appendix K and is not being cited separately.
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. In your response, you also should address your actions to ensure that opportunities to identify existing problems are recognized promptly so that appropriate corrective actions are taken. 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, its enclosure, and your response will be placed in the NRC Public Document Room (PDR). To the extent possible, your response should not include any personal privacy, proprietary, or safeguards information so that it can be placed in the PDR without redaction.
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, Hubert J. Miller Regional Administrator
Docket No. 50-271
License No. DPR-28
Enclosure: Notice of Violation and
Proposed Imposition of Civil Penalty
R. Wanczyk, Plant Manager
J. Thayer, Vice President - Engineering, Vermont Yankee Nuclear Power Corporation
J. Duffy, Licensing Engineer, Vermont Yankee Nuclear Power Corporation
J. Gilroy, Director, Vermont Public Interest Research Group, Incorporated
D. Reid, Vice President - Operations
D. Tefft, Administrator, Bureau of Radiological Health, State of New Hampshire
Chief, Safety Unit, Office of the Attorney General, Commonwealth of Massachusetts
R. Gad, Esquire
G. Bisbee, Esquire
T. Rapone, Massachusetts Executive Office of Public Safety
State of New Hampshire, SLO Designee
R. Sedano, State of Vermont, SLO Designee
Commonwealth of Massachusetts, SLO Designee
PROPOSED IMPOSITION OF CIVIL PENALTY
Vermont Yankee Nuclear Power Corporation Docket No. 50-271 Vermont Yankee Nuclear Power Station License No. DPR-28 EA 96-210
During an NRC inspection conducted from June 3 through June 14, 1996, a violation of NRC requirements was identified. In accordance with the "General Statement of Policy and Procedure for NRC Enforcement Actions," NUREG-1600, the Nuclear Regulatory Commission proposes to impose a civil penalty pursuant to Section 234 of the Atomic Energy Act of 1954, as amended (Act), 42 U.S.C. 2282, and 10 CFR 2.205. The particular violation and associated civil penalty are set forth below:
10 CFR Part 50, Appendix K, Section D.1, Single Failure Criterion, requires, in part, that an analysis of possible failure modes of Emergency Core Cooling System (ECCS) equipment and of their effects on ECCS performance must be made. In carrying out the accident evaluation, the combination of ECCS subsystems assumed to be operative shall be those available after the most damaging single failure of ECCS equipment has taken place.
Contrary to the above, prior to April 26, 1996, the licensee did not perform an analysis of possible failure modes of ECCS equipment and of their effects on the ECCS performance that included an analysis of the most damaging single failure vulnerability of the ECCS equipment for certain loss of coolant accidents (LOCAs). Specifically, LOCA analyses performed for operating Cycles 17 and 18 by licensee staff, and the LOCA analyses performed by contractor (General Electric) staff for Cycle 16, and earlier, (performed pursuant to 10 CFR Part 50, Appendix K) did not evaluate or acknowledge the single failure vulnerability that existed for certain loss of coolant accidents. In particular, for certain intermediate or small break LOCAs, a single failure vulnerability existed since 1974 in that for each train of the Residual Heat Removal (RHR) System, the two pumps per train were powered from separate emergency diesel generators (EDGs), and the minimum flow valve for the train, which was normally closed, was powered from one of those EDGs. A loss of the EDG that powered the minimum flow valve for that train would disable not only the RHR pump powered by that same EDG, but also could result in damage to the RHR pump powered by the other EDG because of the lack of minimum flow for pump cooling. (01013)
This is a Severity Level III violation (Supplement I).
Civil Penalty - $50,000
Pursuant to the provisions of 10 CFR 2.201, Vermont Yankee Nuclear Power Corporation (Licensee) is hereby required to submit a written statement or explanation to the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, within 30 days of the date of this Notice of Violation and Proposed Imposition of Civil Penalty (Notice). This reply should be clearly marked as a "Reply to a Notice of Violation" and should include for each alleged violation: (1) admission or denial of the alleged violation, (2) the reasons for the violation if admitted, and if denied, the reasons why, (3) the corrective steps that have been taken and the results achieved, (4) the corrective steps that will be taken to avoid further violations, and (5) the date when full compliance will be achieved.
If an adequate reply is not received within the time specified in this Notice, an Order or a Demand for Information may be issued as to why the license should not be modified, suspended, or revoked or why such other action as may be proper should not be taken. Consideration may be given to extending the response time for good cause shown. Under the authority of Section 182 of the Act, 42 U.S.C. 2232, this response shall be submitted under oath or affirmation.
Within the same time as provided for the response required above under 10 CFR 2.201, the Licensee may pay the civil penalty by letter addressed to the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, with a check, draft, money order, or electronic transfer payable to the Treasurer of the United States, or may protest imposition of the civil penalty in whole or in part, by a written answer addressed to the Director, Office of Enforcement, U.S. Nuclear Regulatory Commission. Should the Licensee fail to answer within the time specified, an order imposing the civil penalty will be issued. Should the Licensee elect to file an answer in accordance with 10 CFR 2.205 protesting the civil penalty, in whole or in part, such answer should be clearly marked as an "Answer to a Notice of Violation" and may: (1) deny the violation(s) listed in this Notice, in whole or in part, (2) demonstrate extenuating circumstances, (3) show error in this Notice, or (4) show other reasons why the penalty should not be imposed. In addition to protesting the civil penalty in whole or in part, such answer may request remission or mitigation of the penalty.
Any written answer in accordance with 10 CFR 2.205 should be set forth separately from the statement or explanation in reply pursuant to 10 CFR 2.201, but may incorporate parts of the 10 CFR 2.201 reply by specific reference (e.g., citing page and paragraph numbers) to avoid repetition. The attention of the Licensee is directed to the other provisions of 10 CFR 2.205, regarding the procedure for imposing a civil penalty.
Upon failure to pay any civil penalty due that subsequently has been determined in accordance with the applicable provisions of 10 CFR 2.205, this matter may be referred to the Attorney General, and the penalty, unless compromised, remitted, or mitigated, may be collected by civil action pursuant to Section 234c of the Act, 42 U.S.C. 2282c.
The response noted above (Reply to Notice of Violation, letter with payment of civil penalty, and Answer to a Notice of Violation) should be addressed to: James Lieberman, Director, Office of Enforcement, U.S. Nuclear Regulatory Commission, One White Flint North, 11555 Rockville Pike, Rockville, MD 20852-2738, with a copy to the Regional Administrator, U.S. Nuclear Regulatory Commission, Region I, and a copy to the NRC Senior Resident Inspector at the facility that is the subject of this Notice.
Because your response will be placed in the NRC Public Document Room (PDR), to the extent possible, it should not include any personal privacy, proprietary, or safeguards information so that it can be placed in the PDR. If redactions are required, a proprietary version containing brackets placed around the proprietary, privacy, and/or safeguards information should be submitted. In addition, a non-proprietary version with the information in the brackets redacted should be submitted to be placed in the PDR.
Dated at King of Prussia, Pennsylvania
this 23rd day of August 1996