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
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
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Outline
- Background
- Purpose
- Proposed Changes
- Overall Process
- Proposed Pilot Effort
- Challenges
- Project Schedule
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=
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
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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.
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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
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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
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Overall Process - The Start
- Scoping Establish/Implement Maintenance
- Safety Significance Determination Scoping Strategy - Establish HSS and LSS functions/SSCs considering insights from the Birnbaum importance measure (evaluated during pilot)
- Establish/Implement Maintenance Safety Strategy (a)(1) - (a)(2)
Significance Determination - Currently well-established Determination equipment reliability program
- (a)(1)-(a)(2) Determination
- Based on the effectiveness of the component-specific maintenance strategy
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Overall Process - Steady State Establish/Implement Perform * (a)(1)-(a)(2) Determination Maintenance Maintenance - Based on the effectiveness of the Strategy Strategy component-specific maintenance strategy
- (a)(1)
- Components that are not currently effectively controlled via preventive (a)(1) - (a)(2) maintenance (a)(1)
Determination (a)(2) * (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
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Overall Process - Reacting to Failures - Part I IR/CR for Scoped
- Issue Report (IR)/Condition SSC Report (CR) Initiated
- If the failure is associated with an CAP Cause Event?
Evaluation HSS function and is either a No Maintenance Rule Functional Yes failure (MRFF) or a Condition Yes Monitoring Event (CME) a CAP MRFF or HSS? cause evaluation is performed CME?
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Overall Process - Reacting to Failures - Part II MRFF or Yes HSS?
- LSS failures are inputs for CME?
trending under the (a)(3)
No No assessment
- HSS failures that are not MRFF or CAP Cause CME are inputs for trending under Evaluation the (a)(3) assessment
- If a trend is identified, a CAP cause evaluation is performed Yes Trend (a)(3) Assessment Identified?
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Overall Process - (a)(1) Loop (a)(1) (a)(1) - (a)(2)
Determination
- (a)(1) process is essentially the same Establish
- Ensure that monitoring Corrective performance to goals is focused Actions and Goals on the effectiveness of changes to the Maintenance Strategy Monitor Performance to Goals No Yes Perform Cause Are Goals Met?
Evaluation
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Overall Process - CDF Trending CAP Cause
- Core Damage Frequency (CDF)
Evaluation Trending uses the (a)(4) configuration risk management process to provide unavailability Yes data for trending Trend (a)(3) Assessment Identified?
- Both a holistic and detailed suite of unavailability data No CDF Trending
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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)
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Overall Process - (a)(1) - (a)(2) Determination
- If (a)(1) goals are met or there is a (a)(1)
(a)(1) - (a)(2) (a)(2) CAP cause evaluation performed Determination resulting from a PLE, HSS functional failure or CME, or identified trend from the (a)(3) assessment, then an (a)(1)-(a)(2)
Yes determination is performed CAP Cause Are Goals Met? Evaluation
- Based on the (a)(1)-(a)(2) determination, the SSC is either placed in (a)(1) or (a)(2)
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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).
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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 4th quarter 2018 or 1st quarter 2019
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Challenges
- Change management
- Applicability of current enforcement and inspection guidance
- 50.65 is a performance-based rule
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Project Schedule
- September- Workshop/Training for pilot plants
- Fall 2018 - Pilots develop station procedures
- 4th quarter 2018/1st quarter 2019 - Begin pilot process (1 year duration)
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QUESTIONS?
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