ML20216J353

Responds to NRC Re Violations Noted in Insp Rept 50-271/99-12 on 990628-0811.Corrective Actions:Based on RFO 20 Maint Rule Outage Performance Review,Task Was Generated to Clarify & Enhance SD Monitoring Process

ML20216J353
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	09/29/1999
From:	Wanczyk R VERMONT YANKEE NUCLEAR POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
50-271-99-12, NUDOCS 9910050070
Download: ML20216J353 (4)

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VERMONT YANKEE y!

NUCLEAR POWER CORPORATION

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1815 Old Ferry Road, Brattleboro, VT 05301-7002 (802) 257-5271 September 29,1999 BVY 99-125 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

References:

(a)

Letter, USNRC to VYNPC," Maintenance Rule Team Inspection Report No. 50-271/97 8i."T/Y 98-12, dated February 5,1998.

(b)

Lewr, UShRC to VYNPC, "NRC Inspection Report No. 50-271/99-12 and Notice of Violation," NVY 99-77, dated August 19,1999.

Subject:

Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)

Reply to a Notice of Violation - NRC Inspection Report No. 99-12 This letter is 1Titten in response to Reference (b), which documents the findings of an inspection conducted from June 28 to August 11,1999. The inspection identified a violation of regulatory requirements regarding our implementation of 10CFR50.65. Our response to the violation is provided below.

VIOLATION 10 CFR 50.65(a)(3) requires,in part, that performance and condition monitoring activities and associated goals and preventive maintenance activities shall be evaluated at least every refueling outage. Adjustments shall be made where necessary to ensure that the objective of preventing failures of structures, systems, and components through maintenence (reliability) is appropriately balanced against the objective of minimizing tnavailability of structures, systems, and components (SSCs) due to monitoring or preventive maintenance.

Contrary to the above, the periodic assessment conducted for the period November 1996 through May 1998 did not adequately evaluate the maintenance activities to ensure that reliability was appropriately balanced cgainst unavailability for several risk significant systems. Specifically, unavailability monitoring of SSCs during the refueling outage conducted from March 21,1998 to May 31,1998, was accomplished by monitoring key plant safety functions (l.c., decay heat removal; coolant inventory control) rather than monitoring the unavailability cf the specific SSCs. As a result, total unavailability was not properly c:nsidered and assessed for certain in-scope, risk significant systems. Without considering the unavailability cf these SSCs during the refueling outage, the balancing of unavailability and reliability was not accurate.

F:r example, the licensee did not account for approximately 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> of unavailability of the residual heat removal (RHR) shutdown cooling function during the refuel outage. If the unavailability during the refueling outage had been considered, the RIIR shuidown cooling function would have been considered for i

monitoring as required by 10 CFR 50.65(a)(1).

V Additional examples of other risk significant systems where unavailability was inadequately measured and cppropriate balancing could not be done included: AC electrical (115 and 345 KV systems); Control Rod Drive (CRD) system; Emergency Diesel Generator (EDG) Train B; 125 VDC/ Main Station Battery, and Core Spray Train A.

1 This is Severity LevelIV Violation.

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9910050070 990929 PDR ADOCK 05000271 G

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~ BVY 99-125 / page 2.

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VERMONT DNKEE NUCLEAR POWER CORPORATION

RESPONSE

f Ranson for the Violation Vermont Yankee (VY) does not contest this violation, it is our understanding that this Notice of Violation has been' issued due to the NRC's belief that VY is not

' adequately evaluating maintenance activities to ensure that reliability is appropriately balanced against unavailability, for risk significant SSCs, during refueling outages and therefore does not meet the requirements of paragraph (a)(3) of the Maintenance Rule 70CFR50.65). Specifically, the ability "... to ensure that the' objective cf preventing failures 'of structures, systems,' and components through maintenance is. appropriately balanced against the objective of minimizing' unavailability of structures, systems, and components due to monitoring or preventive. maintenance.". The violation states that VY's practice of monitoring Key Plant Safety Functions as

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opposed to unavailability (hours) of specific SSCs, during refueling outages, results in improper monitoring of s unavailability and ultimately inaccurate balancing of unavailability and reliability. Additionally, the violation notes that the condition was identified by the NRC and should have been reasonably prevented by corrective actions for a previous violation.

Based on verbal communications and the closure statements contained in Maintenance Rule Baseline Inspection.

- Report (Reference a), we had concluded that the immediate corrective actions taken to address Violation 97-81-01 I

1 sufficieatly addressed NRC concerns and brought us into compliance with the intent of the Maintenance Rule.

Based on. discussions that took place during the latest inspection, it appears that the expectation was that quantitative versus qualitative assessment methods would be utilized to measure performance. Also, during that discussion, it became apparent that the Commission expects a level of outage unavailability monitoring that is beyond the original philosophy i.e., when a function is not required by Technical Specifications or other controlling plant documents, then unavailability is not an issue.

o Correctis e Steps That Have Beco faken and the Results Achieved:

The current violation was entered into our corrective action process on 8/30/99 (Event Report 99-1031).

Based on ths RFO'20 Maintenance Rule Outage Performance Review, a task was generated (MRULE-20RFO_l) on 11/25/98 to clarify and enhance the shutdown monitoring process. This revision to our monitoring guideline provides for the development of specific SSC unavailability targets (scheduling estimates) associated with scheduled SSC out-of-service windows. In addition to the Key Plant Safety Function monitoring, SSC specific unavailability targets are developed based on a review of the approved outage schedule and the planned out-of-service windows for the identified SSCs.

Development of quantitative unavailability targets based on this schedule following independent Review Group review provides for appropriate criteria that are commensurate with safety and are relative to the scope of the j

current outage. It is felt that these targets provide focus on those SSCs that warrant review.

Corrective Stens That Will Be Taken to Avoid Further Violations:

The VY Maintenance' Rule Program will be revised to clearly reflect the utilization of scheduled hours as the

- criterion used to assess the performance of SSCs required during refuci outage periods. Utilizing a schedule

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reviewed for overall safety impact by the Independent Review Group, individual SSC schedule performance will be

- assessed to determine the effectiveness of maintenance performed.

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BVY 99-125 / page 3.

VERMONT YANKEE NUCLEAR POWER CORPORATION De unavailability criteria of risk significant SSCs will be outage specific and will be based on the approved outage schedule for each RFO. This criterion will consist of the " hours" that an SSC is estimated to be out-of-service during the refuel outage. The " hours" estimate suffices to addmss the issue of assessing maintenance effectiveness and also provides supplemental quantitative criteria by which to assess the balance between reliability and

. availability. The scheduled hours are based on the Preventative Maintenance program and other corrective maintenance activities. Additionally, the process which VY uses to verify the adherence to safety during refueling outages i.e., planning states, will also be maintained. Exceeding either of the established criteria, " planning state" or the " unavailability window," will tilgger an evaluation. The performance evaluation will be conducted including development of necessary corrective actions / maintenance adjustments to restore an acceptable balance when cppropriate in accordance with the Maintenance Rule Program.

The Maintenance Rule Coordinator is responsible for tracking the progress of the outage activities on a daily basis during the erfueling period. This process is documented within the Implementation Guidelines of the VY Maintenance Rule Program.

Date When Full Comoliance Will Be Aebleved:

As stated above, VY will implement the above outage monitoring methodology during the upcoming refuel outage, RFO 21, scheduled to begin on October 29,1999.

Vermont Yankee believes there are still some misunderstandings regarding the program in place to specifically assess outage-related maintenance. We propose to have a meeting in the Region with the appropriate NRC staff to discuss these issues prior to our upcoming refueling outage. We will coordinate this meeting with the Resident Inspector.

We trust that the information provided is responsive to your concerns. Should you have any questions or desire additional information, please contact us.

Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION

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hlf tTNNGV2 Robert J. War y

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Director of fety nd Regulatory Affairs cc:

USNRC Region 1 Administrator x

USNRC Resident Inspector-VYNPS USNRC Project Manager-VYNPS Vermont Department of Public Service

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I SUMh(ARY OF VERMONT YANKEE COMMITMENTS BVY NO.: BVY 99-125 The following' table identifies commitments made in this document by Vermont Yankee Any other actions discussed in the submittal sepresent intended or planned actions by Vermont Yankee. They are described to the NRC for the NRC's information and are not regulatory commitments. Please notify the Licensing Manager of any questions regarding this document or any associated commitments.

j COMMITMENT COMMITTED DATE OR " OUTAGE" VY Maintenance Rule Program will be revised to reflect the OUTAGE utilization of scheduled hours as the criterion to assess the performance of SSCs required during refueling outage periods.

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