IR 05000271/1999012

Insp Rept 50-271/99-12 on 990628-0811.Violation Noted.Major Areas Inspected:Maint Rule Periodic Evaluation Required by 10CFR50.65(a)(3)

ML20211H115
Person / Time
Site:	Vermont Yankee
Issue date:	08/19/1999
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20211H087	List: IR 05000271/1999012 ML20211H085 ML20211H089
References
50-271-99-12, NUDOCS 9909020022
Download: ML20211H115 (7)

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U.S. NUCLEAR REGULATOR ' COMMISSION REGIO J l Docket N . License N DRP-28 Report No., 99-12 Licenses: Vermont Yankee Nuclear Power Corporation Facility: Vermont Yankee Nuclear Power Station

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I Location: Vernon, Vermont i

Dates: June 28 to August 11,1999 Inspector. , . Julian H. 'Niiliams, Senior Operations Engineer

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Approved by: Richard J. Conte, Chief Human Performance and Emergency Preparedness Branch -;

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9909020022 990819 PDR ADOCK 05000271 *

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EXECUTIVE SUMMARY Vermont Yankee Nuclear Power Station NRC Inspection Report No. 50-271/99-12 This inspection reviewed the maintenance rule periodic evaluation required by 10 CFR ,

50.65(a)(3). The report covered a one week on-site period and subsequent document review in !

the King of Prussia office by a regionalinspecto I Maintenance

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The evaluation of risk significant (a)(1) and (a)(2) structures, systems and components )

(SSCs) that were reviewed by the inspector were done in a satisfactory manne . The evaluation of several SSCs including some risk significant SSCs were not documented in the periodic assessment and this indicated a lack of attention to

' maintenance rule activitie . Monitoring of equipment performance during the refueling outage from March 21,1998 j to May 31,1998 was not adequate to assess maintenance effectiveness or to balance )

reliability and unavailability for a number of risk significant SSCs. This was a violation of NRC requirements. The violation was cited because it was identified by the NRC and could have reasonable been provided by correction actions for a previous violatio !

Also, the violation was not placed into the corrective action progra i

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Report Details 11. MAINTENANCE

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M1 - Conduct of Maintenance M1.1- Maintenance Rule Periodic Assessment

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Inspection Scope (62707)

' The inspector reviewed the periodic evaluation required by paragraph (a)(3) of the maintenance rule...This review included the verification that performance and condition monitoring activities and goals and preventive maintenance activities were evaluated and

' industry-wide operating experience was used where practical. It also included verification that adjustments were made where necessary to ensure that the objective of preventing failures of structures, systems, and components (SSCs) through maintenance was appropriately balanced against the objective of minimizing unavailability of SSCs due to monitoring or preventive maintenance activities. The inspector verified that the periodic assessment for the period November 1996 through May 1998 (Cycle 19) was

, completed in a timely manne Observations and Findinas '

The inspector reviewed activities (such as goals setting, performance criteria

. evaluations, monitoring performance, use of industry operating experience, and

- corrective actions) associated with selected risk significant (a)(1) and (a)(2) SSCs. For those SSCs reviewed, the activities were satisfactor During the review of the periodic assessment the inspector noted that not all in-scope SSCs were included in the assessment. In discussions with the maintenance rule coordinator (MRC), it was determined that some system engineers did not provide inputs to the periodic assessment that were included in Tab 2 (Individual System

. Assessments). Upon further review by the MRC, he indicated that all SSCs were included in the periodic assessment but the documentation was weak or missing. In several places in the assessment, reference is made to the SSC evaluations in Tab 2 for the (a)(3) required assessments. However, the following systems were not included in Tab 2:

Building and Structures Circulating Water Hoists RHR Service Water Stator Cooling Seal Oil Service Water 1 Main Turbine Generator Turbine Lube Oil

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After additional information was supplied, the inspector determined that the required

- periodic assessment could have been completed for the SSCs missing from Tab 2. The inspector determined that the periodic assessment indicated a lack of attention to detail in maintenance rule activitie CFR 50.65 (a)(3) states that adjustments shall be made where necessary to ensure l

. that the objective of preventative failures of SSCs through maintenance is appropriately balanced against the objective of minimizing unavailability of SSCs due to monitoring or preventative maintenance. The inspector reviewed the balancing of reliability and unavailability of risk significant SSCs. Balancing for"at power conditions" was- i completed for those SSCs reviewed. Balancing of reliability and unavailability during the refuel outage was not done and is discussed belo j The Outage Performance Review dated 11/19/98 was part of the periodic assessment i and addressed SSC performance during the outage. Unavailability was defined in the i Vermont Yankee Maintenance Rule program as "the period of time, during the l monitoring period, that a SSC is not capable of performing its intended function when the intended function is required or may be demanded as a fraction of the total time (hours) '

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during the monitoring period". Unavailability monitoring for risk significant SSCs was accomplished through a review of outage performance. Monitoring was against the ,

following key plant safety functions; decay heat removal reactivity control i coolant inventory control l containment availability AC and DC electrical power Monitoring these key safety functions is important for managing plant risk during the outage but this practice does not monitor the effectiveness of maintenance on specific SSCs nor does it allow a meaningful balancing of reliability and unavailability. The inspector noted that the maintenance rule baseline inspection (MRBI) found that risk !

significant SSCs were not monitored for unavailability during a previous refuel outage I and the MRBI cited this practice as a violation of 10 CFR 50.65(a)(2). Vermont Yankee's i response to the violation was to revise Guideline No. 9, "SSC Performance Monitoring,"

to assess the ability to meet minimum daily planning states for key plant safety function This was considered by W a measure of unavailability of key plant systems against the detailed outage plan and was sufficient to meet the requirements of 10 CFR 50.65 (a)(2).

However, the NRC cautioned W that failure to monitor unavailability during a refuel outage could result in ineffective periodic balancing of unavailability and reliability as required by 10 CFR 50.65(a)(3).

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The inspector reviewed the " Outage Performance Review" (Tab 8), which was part of the periodic assessment covering the refueling outage. There were many maintenance activities during this period that were not effectively integrated in the individual system assessments performed by the responsible system engineers. Performance measures for risk significant systems worked on during the outage appeared to be estimates for the i time to complete the work and had little, if any, safety or PRA basis. In many cases, the !

Outage Performance Review did not appear to capture all of the SSC outage time. VY {

did appear to schedule equipment outages using plant risk as a r:onsideratio By the VY program, risk is managed by properly planning and conducting activities during the outage. " Minimum" safety function status was defined as meeting minimum technical specifications requirement '

i The outage assessment states that the decay heat removal safety function ( defined as 1 functional residual heat removal (RHR) loop,1 residual heat removal senrice water !

. (RHRSW) heat exchanger and 1 RHRSW pump) was below minimum on three separate occasions (totaling about 10 days of the planned 20 day outage). This outage time amounted to about 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> of unavailability for the shutdown heat removal function of RHR during the outage which was not accounted for in balancing reliability and unavailability. Unavailability performance criteria for each of two trains was 0.84% ;

(203 hrs) per 3 years of "at power conditions". The actual "at power * unavailability as reported by the licenste of train A was 0.74% and train B was 0.82%. Both trains were ;

in "(a)(2) with review" which provided an increased level of monitoring. If the l unavailability during the refuel outage had been adequately considered, the RHR Shutdown Cooling function would have been considered for placement into (a)(1) with I goals established, and a corrective action program develope Other risk significant systems required to be functional during shutdown where i unavailability was not properly measured and balancing could not be done include:

AC electncal (115 KV and 345 KV)- These systems had times of unavailability I loosely defined for the outage but the time was not considered in balancing. Both systems had "at power" unavailability performance criteria of 0.84% per three years. The actual "at power" unavailability as reported by the licensee was 0.18% for the 115 KV system and 0.09% for the 345 KV system. Both systems were in (a)(2).

Control Rod Drive (CRD)- This system had 82 hours9.490741e-4 days <br />0.0228 hours <br />1.35582e-4 weeks <br />3.1201e-5 months <br /> of " planned" unavailability which was actually 153 hours0.00177 days <br />0.0425 hours <br />2.529762e-4 weeks <br />5.82165e-5 months <br /> of unavailability not included in balancing. The B train of CRD has unavailability performance criteria of 1.79% for 3 years (432 hrs)

for "at power conditions". Actual "at power" unavailability as rarted by the licensee was 2.48% and the B train was in (a)(1).

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Emeroency Diesel Generator (EDG) Train B- A planned five day outage tumed out to be a 12 day (288 hrs) outage which was not considered in balancin Unavailability performance criteria for "at power conditions' for each train is 1.93% (466 hrs) per 3 years. The actual "at power" unavailability as reported by the licensee was 0.91% for the B train and it was an (a)(2) syste l 125 VDC/ Main Station Battery- A 3 day planned outage took 10 days (240 hrs) l and the unavailability was not considered in balancing. Unavailability criteria was )

revised during the periodic assessment from 0.36% to 0.61% (162 hrs) per !

3 years for "at power conditions". Actual"at power" unavailabiGty was 0.48% and the system was "(a)(2) with review" which provided an increased level of monitorin Core Sorav Train A- A planned 3 day outage took 13 days (312 hrs) and the ,

unavailability was not considered in balancing. Unavailability performance I criteria for each train is 0.84% (203 hrs) per 3 years for "at power conditions". I The actual 'at power" unavailability as reported by the licensee was 0.03% and the system was (a)(2).

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The inspector discussed with facility representatives the need to measure unavailability or some similar performance parameter when a risk significant system was required to i

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be functional. The inspector also discussed the difference between managing plant risks and monitoring maintenance effectiveness. The licensee representatives did not appear to agree with this need when the plant was shutdown even when the function was required to be available. The licensee's position was that as long as the critical plant safety function was monitored, the system function does not have to be monitored against established performance criteria. The maintenance rule applies to all operational states of the plant and unavailability is required to be monitored when a risk significant SSC is required to t;e functional. Failure to do so does not allow balancing reliability and unavailability of risk significant SSCs, and is a violation of 10 CFR 50.65 (a)(3). (VIO 50-271/99-12-01). The violation is being cited because it was NRC identified and was repetitive as a result of inadequate corrective action for a previous violation. This i violation could reasonably have been prevented by the corrective actions for the previously cited violation of 10 CFR 50.65. Also, the violation was not placed into the corrective action progra c. Conclusions The evaluation of risk significant (a)(1) and (a)(2) SSCs that were reviewed were done in a satisfactory manne The periodic evaluation of several SSCs including some risk significant SSCs were not documented in the assessment and this indicated a lack of attention to maintenance rule activitie .

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i Monitoring of equipment performance during the refuel outage was not adequate to l assess maintenance effectiveness or balance reliability and unavailability for risk l significant SSCs. This was a violation of NRC requirements. The violation was cited because it was identified by the NRC and could have been reasonably been prevented by corrective action for a previous violatio ;

X1 Exit Meeting Summary i l

The inspector met with licensee representatives periodically throughout the inspection. A '

telephone exit was conducted on July 30,1999. Additional telephone conversations to discuss the findings were conducted from July 30,1999 to August 11,1999. During the exit, the scope and findings of the inspection were reviewed and discussed, including the violatio ITEMS OPENED, CLOSED, OR DISCUSSED i l

Opened VIO 99-12-01 Failure to balance reliability and unavailability in the periodic evaluation required l 10 CFR50.65(a)(3). )

LIST OF ACRONYMS USED i

AC Altemating current CFR . Code of Federal Regulations CRD Control Rod Drive l EA Enforcement Action  !

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EDG' Emergency Diesel Generator KV Kilovolts MRC Maintenance Rule Coordinator l MRBI ' Maintenance Rule Baseline Inspection  !

NRC Nuclear Regulatory Commission l PDR Public Document Room PRA Probabilistic Risk Assessment RH Residual Heat Removal RHRSW Residual Heat Removal Service Water SSC Structures, Systems, and Components VDC Volts Direct Current VY Vermont Yankee

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