ML18166A093
| ML18166A093 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 06/20/2018 |
| From: | Burr J, Ellgass L, Linthicum R, McLain M, Sibley C, Vaughn S, Zapetis J Arizona Public Service Co, Exelon Corp, Nuclear Energy Institute, PWR Owners Group, Tennessee Valley Authority, Wolf Creek |
| To: | Office of Nuclear Reactor Regulation |
| Lewin A, NRR/DIRS, 415-2259 | |
| References | |
| Download: ML18166A093 (19) | |
Text
© NEI 2018. All rights reserved. For use by NEI members only.
An Alternate Approach to NUMARC 93
-01 Chuck Sibley (Wolf Creek)
Jenna Burr (Exelon)
Jim Zapetis (Exelon)
Mike McLain (APS)
Larry Ellgass (TVA)
Roy Linthicum (PWROG)
Steve Vaughn (NEI)
June 20, 2018 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Outline *Background
- Purpose *Proposed Changes
- Overall Process
- Proposed Pilot Effort
- Challenges
- Project Schedule 2 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Background
- Delivering the Nuclear Promise Initiative (early 2017)
- Focus resources on high safety significant functions
- Gain efficiencies in the interface between the Maintenance Rule program and other station programs
- Leverage improvements in data collection/analysis and system monitoring 3 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Purpose *Provide utilities with a risk
-informed framework that supports the implementation and monitoring of a maintenance effectiveness program that complies with 10 CFR 50.65, effectively and efficiently leverages utility resources, and is focused on equipment performance commensurate with safety.
4 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Proposed Changes
- Focus energy on determining the effectiveness of the maintenance strategy, not whether performance criteria are met -Address every High Safety Significant functional failure in near real time -Trend Low Safety Significant failures in CAP and evaluate in the (a)(3) assessment
-Leverage the (a)(4) configuration risk management program (i.e., CDF Trending) for unavailability insights during the (a)(3) assessment
- Consider using the Birnbaum importance measure as an additional tool in determining safety significance 5 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Proposed Changes
- Perform causal evaluations commensurate with safety
-A trend of low safety significant failures warrants an appropriate causal evaluation.
-All HSS functional failures and Plant Level Events warrant a near real time causal evaluation 6 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - The Start *Scoping *Safety Significance Determination
-Establish HSS and LSS functions/SSCs considering insights from the Birnbaum importance measure (evaluated during pilot)
- Establish/Implement Maintenance Strategy -Currently well
-established equipment reliability program
- (a)(1)-(a)(2) Determination
-Based on the effectiveness of the component-specific maintenance strategy ScopingSafety Significance DeterminationEstablish/Implement Maintenance Strategy (a)(1) - (a)(2) Determination 7 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - Steady State
- (a)(1)-(a)(2) Determination
-Based on the effectiveness of the component-specific maintenance strategy *(a)(1) -Components that are not currently effectively controlled via preventive maintenance
- (a)(2) -Components that are currently effectively controlled via preventive maintenance
- Perform Maintenance Strategy
-Execute the planned preventive maintenance as described via the maintenance strategy Establish/Implement Maintenance Strategy (a)(1) - (a)(2) DeterminationPerform Maintenance Strategy (a)(2)(a)(1)8 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - Reacting to Failures
- Part I *Issue Report (IR)/Condition Report (CR) Initiated
- If the failure is associated with an HSS function and is either a Maintenance Rule Functional failure (MRFF) or a Condition Monitoring Event (CME) a CAP cause evaluation is performed IR/CR for Scoped SSCPlant Level Event?HSS?MRFF or CME?CAP Cause EvaluationYes Yes Yes No 9 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - Reacting to Failures
- Part II *LSS failures are inputs for trending under the (a)(3) assessment
- HSS failures that are not MRFF or CME are inputs for trending under the (a)(3) assessment
- If a trend is identified, a CAP cause evaluation is performed HSS?MRFF or CME?(a)(3) AssessmentTrend Identified
?CAP Cause EvaluationYes Yes No No 10 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - (a)(1) Loop
- (a)(1) process is essentially the same *Ensure that monitoring performance to goals is focused on the effectiveness of changes to the Maintenance Strategy (a)(1) - (a)(2) Determination (a)(1)Establish Corrective Actions and GoalsMonitor Performance to GoalsAre Goals Met
?Perform Cause Evaluation No Yes 11 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - CDF Trending
- Core Damage Frequency (CDF) Trending uses the (a)(4) configuration risk management process to provide unavailability data for trending
- Both a holistic and detailed suite of unavailability data (a)(3) AssessmentTrend Identified
?CAP Cause EvaluationYes No CDF Trending 12 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process
- CDF Trending *Actual average CDF compared to present limits *Evaluate periods of higher risk
-Could they have been avoided? -Indications of higher than average risk
-If evaluation results in changes to maintenance strategy, evaluate for (a)(1) 13 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process - (a)(1) - (a)(2) Determination
- If (a)(1) goals are met or there is a CAP cause evaluation performed resulting from a PLE, HSS functional failure or CME, or identified trend from the (a)(3) assessment, then an (a)(1)
-(a)(2) determination is performed
- Based on the (a)(1)-(a)(2) determination, the SSC is either placed in (a)(1) or (a)(2)
CAP Cause EvaluationAre Goals Met
?(a)(1) - (a)(2) Determination (a)(1)(a)(2)Yes 14 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Overall Process
- Example #1
- Component: HPSI Injection Valve
- Function: Indirect Radiation Release
- Safety Significance: High *Description: Body to bonnet leak estimated to exceed the TRM limit. Determined to be a MRFF. Cause
- failure to follow work instructions resulting in an inadequate weld.
- NUMARC 93-01: Performance criteria: 3 failures, 36 months, remained in (a)(2).
- Proposed Process: (a)(1)-(a)(2) determination would consider changes to the maintenance strategy given the ineffectiveness of maintenance (inadequate weld).
15 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Proposed Pilot Effort
- At least one pilot in each Region
- Some stations will pilot the entire MR program while others will pilot just several systems
- Pilots will not be implementing the NUMARC 93
-01 process in parallel for the systems being piloted
- Pilot starts in 4 th quarter 2018 or 1 st quarter 2019 16 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Challenges
- Change management
- Applicability of current enforcement and inspection guidance *50.65 is a performance
-based rule 17 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
Project Schedule
- September- Workshop/Training for pilot plants *Fall 2018
- Pilots develop station procedures
- 4 th quarter 2018/1 st quarter 2019
- Begin pilot process (1 year duration) 18 DRAFT 6/13/18
© NEI 2018. All rights reserved. For use by NEI members only.
© NEI 2018. All rights reserved. For use by NEI members only.
QUESTIONS?
DRAFT 6/13/18