IR 05000338/2012010
| ML12136A115 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/11/2012 |
| From: | Mccree V Region 2 Administrator |
| To: | Heacock D Virginia Electric & Power Co (VEPCO) |
| References | |
| EA-12-033 IR-12-010 | |
| Download: ML12136A115 (11) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION May 11, 2012
SUBJECT:
FINAL SIGNIFICANCE DETERMINATION OF A WHITE FINDING, NOTICE OF VIOLATION, AND ASSESSMENT FOLLOW-UP LETTER (NRC INSPECTION REPORT 05000338/2012010 AND 05000339/2012010 - NORTH ANNA POWER STATION)
Dear Mr. Heacock:
This letter provides you with the final significance determination of the preliminary Greater than Green finding for both units identified in NRC Inspection Report Nos. 05000338/2012008 and 05000339/2012008, dated March 21, 2012. This finding involved an Apparent Violation (AV) of Technical Specification (TS) 5.4.1.a for the failure to establish and maintain emergency diesel generator (EDG) maintenance procedures as recommended by Regulatory Guide 1.33, Appendix A, Section 9, Procedures for Performing Maintenance. Specifically, maintenance procedure 0-MCM-0701-27 did not provide adequate guidance for the installation of the jacket water cooling inlet jumper gasket which resulted in a faulty gasket installation on the Unit 2 H (2H) EDG in May 2010. As a result, the 2H EDG failed to perform its safety function on August 23, 2011.
At Dominions request, an open regulatory conference was conducted with members of your staff on April 20, 2012, to discuss Dominions views on this issue. During the conference, your staff described your assessment of the significance of the finding (ML12115A082) and agreed with the NRCs characterization of the finding as an AV. However, your staff concluded that this finding is of very low safety significance (Green) for both units. Your staff highlighted several differences between Dominions risk assessment and the NRCs preliminary risk assessment as documented in the NRC inspection report. Specifically, your staff has different views on the exposure time, common cause failure and basic event probabilities from the NRCs risk assessment. VEPCO 2 After considering the information developed during the inspection and the information provided by Dominion during the regulatory conference, the NRC has concluded that the finding is appropriately characterized as White (low to moderate safety significance) for both units, which will require additional NRC inspections. The bases for the NRCs significance determination of this finding, and the differences in Dominions characterization of the finding, are discussed in Enclosure 2. NRCs final Significance Determination Process (SDP) Phase 3 results are discussed in Enclosure 3.
You have 30 calendar days from the date of this letter to appeal the staffs determination of significance for the identified White finding or the Notice of Violation associated with this finding.
An appeal of the White finding will be considered to have merit only if it meets the criteria given in NRC Inspection Manual Chapter 0609, Attachment 2. An appeal must be sent in writing to the Regional Administrator, Region II, U.S. Nuclear Regulatory Commission, 245 Peachtree Center Avenue, Suite 1200, Atlanta, GA 30303-1257.
The NRC also has determined that the finding involving the failure to establish and maintain EDG maintenance procedures as recommended by Regulatory Guide 1.33, Appendix A, Section 9, Procedures for Performing Maintenance is a violation of TS 5.4.1.a. The violation is cited in Enclosure 1, Notice of Violation (Notice) and the circumstances surrounding it are described in detail in NRC Inspection Report 05000338, 339/2011005. In accordance with the NRC Enforcement Policy, the Notice is considered escalated enforcement action because it is associated with a White finding for both units.
The NRC has concluded that information regarding the reason for the violation, the corrective actions taken and planned to correct the violation and prevent recurrence, and the date when full compliance will be achieved is already adequately addressed on the docket in the North Anna Open Regulatory Meeting Summary, dated April 24, 2012 (ML12115A082). Therefore, you are not required to respond to this letter unless the description therein does not accurately reflect your corrective actions or your position. However, you are required to submit a written statement or explanation pursuant 10 CFR 2.201 if the description therein does not accurately reflect your corrective actions or your position. In this case, please follow the instructions specified in the Notice of Violation, Enclosure 1.
For administrative purposes, this letter is issued as a separate NRC Inspection Report, No.
05000338/2012010 and 05000339/2012010. Accordingly, AV 05000338, 339/2011005-02 is updated consistent with the regulatory positions described in this letter. Therefore, AV 05000338, 339/2011005-02 is now Violation 05000338, 339/2011005-02, Failure to Provide Adequate Guidance for Installation of 2H EDG Jacket Water Cooling Inlet Jumper with a safety significance of White and a cross-cutting aspect in the area of problem identification and resolution of operating experience, and the aspect of implementing operating experience, P.2(b).
The NRC has determined the performance of North Anna Power Station Unit 1 and Unit 2 to be in the Regulatory Response Column of the Reactor Oversight Process Action Matrix as of the fourth quarter of calendar year 2011. Therefore, the NRC plans to conduct a supplemental VEPCO 3 inspection in accordance with Inspection Procedure 95001, Supplemental Inspection for One or Two White Inputs in a Strategic Performance Area, to provide assurance that the root causes and contributing causes of the risk-significant performance issues are understood, that the extent of cause is identified, and that your corrective actions for risk-significant performance issues are sufficient to address the root and contributing causes and prevent recurrence. The NRC requests that your staff provide notification of your readiness for the NRC to conduct a supplemental inspection to review the actions taken to address the White inspection finding.
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter, its enclosures, and your response, if you choose to provide one, will be made electronically available for public inspection in the NRC Public Document Room or from the NRCs document system (ADAMS), accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, if you do respond, you should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the public without redaction. If personal privacy or proprietary information is necessary to provide an acceptable response, please provide a bracketed copy of your response that identifies the information that should be protected and a redacted copy of your response that deletes such information. If you request withholding of such information, you must specifically identify the portions of your response that you seek to have withheld and provide in detail the bases for your claim of withholding (e.g., explain why the disclosure of information will create an unwarranted invasion of personal privacy or provide the information required by 10 CFR 2.390(b) to support a request for withholding confidential commercial or financial information). The NRC also includes significant enforcement actions on its Web site at http://www.nrc.gov/reading-rm/doc-collections/enforcement/actions.
Should you have any questions concerning this letter, please contact Mr. Gerald McCoy at 404-997-4551.
Sincerely,
/RA/
Victor M. McCree Regional Administrator Docket Nos. 50-338, 50-339 License Nos. NPF-4, NPF-7 Enclosures:
1. Notice of Violation 2. NRC Basis for Final Significance Determination 3. NRCs Final SDP Phase 3 Results w/Attachments (Removed) _ ML12136A115_______________ X SUNSI REVIEW COMPLETE X FORM 665 ATTACHED OFFICE RII:DRP RII:DRP RII:EICS OE NRR RII:DRP RII:RA SIGNATURE /RA/ /RA/ /RA/ /VIA E-Mail/ /VIA E-Mail/ /RA/ /RA/
NAME SNinh GMcCoy CEvans Clauren MAshley RCroteau LWert DATE 5/3/2012 5/8/2012 5/4/2012 5/4/2012 5/4/2012 5/8/2012 5/10/2012 E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO
OFFICIAL USE ON LY VEPCO 4 cc w/encls: Tom Huber Nelson K. Martin, Manager Director, Nuclear Licensing & Operations Nuclear Fleet Protection Services Support Virginia Electric and Power Company Innsbrook Technical Center Innsbrook Technical Center Electronic Mail Distribution 5000 Dominion Boulevard Glen Allen, VA 23060-6711 Ginger L. Rutherford Virginia Electric and Power Company Margaret A. Earle Electronic Mail Distribution Nuclear Licensing and Operations Support Innsbrook Technical Center Virginia State Corporation Commission 5000 Dominion Boulevard Division of Energy Regulation Glen Allen, VA 23060-6711 P.O. Box 1197 Richmond, VA 23209 cc w/Inspection Summary:
Clarence L. Gum Attorney General Manager, Nuclear Protection Services Supreme Court Building North Anna Power Station 900 East Main Street 1022 Haley Drive Richmond, VA 23219 Mineral, VA 23117 Senior Resident Inspector cc w/o encl: North Anna Power Station Mr. Gerald T. Bischof U.S. Nuclear Regulatory Commission Site Vice President P.O. Box 490 North Anna Power Station Mineral, VA 23117 Virginia Electric & Power Company Electronic Mail Distribution Donald R. Taylor, Licensing Supervisor North Anna Power Station Fred Mladen P. O. Box 402 Director, Station Safety & Licensing Mineral, VA 23117-0402 Virginia Electric and Power Company Electronic Mail Distribution Michael M. Cline, Director Virginia Department of Emergency Services Michael Crist, Plant Manager Management North Anna Power Station Electronic Mail Distribution Virginia Electric & Power Company Electronic Mail Distribution Executive Vice President Old Dominion Electric Cooperative Lillian M. Cuoco, Esq. Electronic Mail Distribution Senior Counsel Dominion Resources Services, Inc. County Administrator Electronic Mail Distribution Louisa County P.O. Box 160 Louisa, VA 23093 OFFICIAL USE ON LY VEPCO 5 Letter to David from Victor M. McCree dated may 11, 2012 SUBJECT: FINAL SIGNIFICANCE DETERMINATION OF A WHITE FINDING, NOTICE OF VIOLATION, AND ASSESSMENT FOLLOW-UP LETTER (NRC INSPECTION REPORT 05000338/2012010 AND 05000339/2012010 - NORTH ANNA POWER STATION)
Distribution w/encls:
C. Evans, RII EICS L. Douglas, RII EICS OE Mail RIDSNRRDIRS PUBLIC RidsNrrPMNorthAnna Resource NOTICE OF VIOLATION North Anna Power Station Docket Nos. 50-338, 50-339 Unit 1 and Unit 2 License Nos. NPF-4, NPF-7 EA-12-033 During an NRC inspection completed on December 31, 2011, a violation of NRC requirements was identified. The circumstances surrounding the violation were described in detail in NRC Inspection Report Nos. 05000338, 339/2011005 dated February 13, 2012. In accordance with the NRC Enforcement Policy, the violation is set forth below:
Technical Specification (TS) 5.4.1.a states, in part, that written procedures shall be established and maintained covering the applicable procedures recommended in Regulatory Guide 1.33, Revision 2, Appendix A, of which Section 9 specifies procedures for performing maintenance.
Regulatory Guide 1.33, Revision 2, Appendix A, Section 9, states, in part, that maintenance that can affect the performance of safety-related equipment should be properly preplanned and performed in accordance with written procedures, documented instructions, or drawings appropriate to the circumstances.
Contrary to the above, from June 2, 2010, until August 23, 2011, the licensee failed to establish and maintain maintenance procedures appropriate to the circumstances for the safety-related EDGs. Specifically, maintenance procedure 0-MCM-0701-27 did not provide adequate guidance for installation of the jacket water cooling inlet jumper gasket which resulted in a faulty gasket installation on the Unit 2 H (2H) EDG in May 2010. As a result, the 2H EDG failed to perform its safety function when called upon on August 23, 2011.
This violation is associated with a White Significance Determination Process finding for both units for the Mitigating Systems cornerstone.
The NRC has concluded that information regarding the reason for the violation, the corrective actions taken and planned to correct the violation and prevent recurrence, and the date when full compliance will be achieved is already adequately addressed on the docket in the North Anna Open Regulatory Meeting Summary, dated April 24, 2012 (ML12115A082). However, you are required to submit a written statement or explanation pursuant to 10 CFR 2.201 if the description therein does not accurately reflect your corrective actions or your position. In this case, or if you choose to respond, clearly mark your response Reply to a Notice of Violation EA-12-033, and send it to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555-0001 with a copy to the Regional Administrator, Region II and a copy to the NRC resident inspector at the facility that is the subject of this Notice, within 30 days of the date of the letter transmitting this Notice of Violation (Notice).
Enclosure 1
If you choose to respond, your response will be made available electronically for public inspection in the NRC Public Document Room or from the NRC=s document system (ADAMS),
assessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. Therefore, to the extent possible, the response should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the public without redaction.
If you contest this enforcement action, you should also provide a copy of your response, with the basis for your denial, to the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-0001.
In accordance with 10 CFR 19.11, you may be required to post this Notice within two working days of receipt.
Dated this 11 day of May 2012.
Enclosure 1
NRC BASIS FOR FINAL SIGNIFICANCE DETERMINATION On April 20, 2012, a regulatory conference was held regarding a coolant leak on the North Anna 2H Emergency Diesel Generator (EDG). During the regulatory conference, the licensee presented their risk assessment for the finding and provided specific discussion related to the exposure time, treatment of common cause failures, and the failure probability for specific basic events present in the dominant sequences for the finding.
The NRC staff has reviewed all the data and information presented by the licensee during the regulatory conference and has reached a final significance determination for this finding. The conclusion is that the risk characterization of the finding is WHITE, a finding of low to moderate safety significance, for both North Anna units. The details supporting this result are contained in the revised phase 3 Significance Determination Process (SDP) risk assessment which is attached as Enclosure 3 to this letter. Each of the specific discussion areas presented by the licensee will be discussed in the following paragraphs.
The licensee identified several specific basic event failure probabilities where the North Anna site specific failure probability differed from the industry average values used by the NRC in the preliminary SDP risk evaluation. The NRC has reviewed the basis for the development of the North Anna site specific basic event failure probabilities presented by the licensee and agrees that a few specific human error probabilities should be changed for use in the final SDP risk evaluation of the finding. Basic event AFW-XHE-XM-CNTRL, Operator Fails to Control Turbine Driven Auxiliary Feedwater (TDAFW) pump was changed from a failure probability of 3.0 E-1 to the licensees value of 1.0 E-1. Additionally, basic event EPS-XHE-XM-AAC Failure to Start and Align the AAC Station Blackout (SBO) Diesel Generator was changed from a failure probability of 1.0 E-1 to the licensees value of 4.4 E-2. These values were used to support the final SDP risk assessment for both North Anna units for this finding. These changes resulted in a reduction of the estimated risk of the finding for both units.
The licensee provided discussion at the Regulatory Conference regarding the NRCs treatment of common cause failure probability for this finding. The EDG gasket installation and staggered test data were provided and the licensee articulated that the failure cause was known and that the issue should be considered an independent failure with the common cause failure probability remaining at nominal value. The NRC has reviewed the licensees data and discussion and has decided that the finding represents a condition that merits treatment for potential common cause failure increase. The performance deficiency identified discrepancies in the EDG maintenance procedure related to the sealant cure time, torque values, and jack bolt adjustments. The licensees root cause evaluation identified insufficient procedural guidance as a contributing cause. The NRC followed established guidance and process for treatment of this issue as a potential common cause failure.
When performing event or condition analysis, NRC assesses the risk incurred not only in the as-found conditions of the observed failure(s) but also, and more importantly, the contribution of potential events associated with the performance deficiency that did not occur but still represent a risk to public health and safety. In other words, when performing an SDP assessment, the Enclosure 2
NRC considers not only what actually happened, but also what could have happened with respect to the performance deficiency. Even if only one failure had occurred, as was the case with this finding, considerations for potential common cause failure (CCF), in addition to potential for other equipment failure, would still be included in the SDP risk assessment. In this case, the observed failure was associated with a proximate cause (e.g., inadequate procedural guidance) capable of impacting other components within the same common cause component group (CCCG), where CCCG can be defined as a group of components that are considered to share a potential for failing due to the same cause. Therefore, the SDP risk assessment for this finding includes considerations of the potential failure of other equipment in the same CCCG due to the same proximate cause.
The licensee presented information from the root cause evaluation and performed some mockup testing to demonstrate that the failure should be considered a demand failure which supported their assertion that the exposure period should be limited to the last EDG surveillance test, a period of 28 days. The licensees root cause evaluation (RCE) observed that the six gasket ridge marks indicated gasket displacement due to a combination of pressure and thermal cycling. The root cause evaluation (RCE) indicated that failure was most likely due to initial installation problems leading to movement over time, and that gasket observations provide clear indication that the failed gasket had been in the process of moving toward failure for some time.
The NRC believes that the evidence provides some insight that the failure mode is most likely time based. The NRC does not agree that the evidence is sufficient to provide reasonable assurance that the failure could not have occurred prior to the last surveillance.
The licensee contention that the ridge marks can be dated and that this provides evidence that the failure could not have occurred prior to the last test is not credible. There is not enough detail provided in the root cause evaluation regarding the initial as-found conditions to support these conclusions. There is a high amount of uncertainty in making these conclusions due to concerns regarding: (1) How the gasket was initially disassembled to ensure that the marks were not made during disassembly, or initially present, or caused by slippage during initial installation; (2) The root cause evaluation does not detail if the marks were present on the reverse of the gasket or on the metal surfaces; (3) The root cause evaluation does not indicate if the marks are indentations in the gasket material or actually made of the sealant material; (4)
The root cause evaluation provides no detail on how the gasket samples were controlled during the investigation process; and (5) The root cause evaluation does not account for the lack of correlation of the makings to the number of heatup and cooldown cycles completed by the engine.
The licensee developed a mockup and performed testing to better understand the gasket failure mode. The mockup test results are also uncertain due to differences between the test apparatus and actual plant conditions specifically: (1) No accounting for vibration or aging affects on the gasket or sealant; and (2) Inability to establish accurate conditions for the failure as there is not sufficient detail on the conditions of the failure as discussed above. The test was not able to reproduce the failure without manually adjusting the jack bolts and the testing was not able to reproduce the ridge marks. The mockup testing does not provide enough proof to support the 28 day exposure period assumption. Due to the uncertainty involved in the gasket failure the NRC performed a sensitivity analysis using a T over 2 exposure time. For this case Enclosure 2
the time T is from gasket installation until gasket failure. The T over 2 is therefore 7.5 months.
This method is described in the NRC Risk Assessment Standardization Project (RASP) manual for conditions when the exact time of failure is not known. The result of the sensitivity analysis was that the risk was WHITE for both units, the same result as for the 10 month exposure period.
In summary, the NRC has reviewed the discussions and material presented at the regulatory conference and has agreed to modify the human error probabilities for manually starting and aligning the station blackout (SBO) diesel and for operator control of the turbine driven auxiliary feedwater (TDAFW) pump. The NRC concluded that the failure has a potential for common cause and that the appropriate exposure period was determined to be 10 months. The resultant final SDP analysis characterized the risk significance of the finding as WHITE for both units.
Enclosure 2