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
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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
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Outline
- Background
- Purpose
- Proposed Changes
- Overall Process
- Proposed Pilot Effort
- Challenges
- Project Schedule 2
DRAFT 6/13/18
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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 3
DRAFT 6/13/18
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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.
4 DRAFT 6/13/18
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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 5
DRAFT 6/13/18
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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 6
DRAFT 6/13/18
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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 Scoping Safety Significance Determination Establish/Implement Maintenance Strategy (a)(1) - (a)(2)
Determination 7
DRAFT 6/13/18
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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)
Determination Perform Maintenance Strategy (a)(2)
(a)(1) 8 DRAFT 6/13/18
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Overall Process - Reacting to Failures - Part I Issue Report (IR)/Condition Report (CR) Initiated Plant Level Events (PLEs) receive a CAP cause evaluation 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 SSC Plant Level Event?
HSS?
MRFF or CME?
CAP Cause Evaluation Yes Yes Yes No 9
DRAFT 6/13/18
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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) Assessment Trend Identified?
CAP Cause Evaluation Yes Yes No No 10 DRAFT 6/13/18
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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 Goals Monitor Performance to Goals Are Goals Met?
Perform Cause Evaluation No Yes 11 DRAFT 6/13/18
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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) Assessment Trend Identified?
CAP Cause Evaluation Yes No CDF Trending 12 DRAFT 6/13/18
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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) 13 DRAFT 6/13/18
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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 Evaluation Are Goals Met?
(a)(1) - (a)(2)
Determination (a)(1)
(a)(2)
Yes 14 DRAFT 6/13/18
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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).
15 DRAFT 6/13/18
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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 16 DRAFT 6/13/18
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Challenges
- Change management
- Applicability of current enforcement and inspection guidance
- 50.65 is a performance-based rule 17 DRAFT 6/13/18
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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) 18 DRAFT 6/13/18
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© NEI 2018. All rights reserved. For use by NEI members only.
QUESTIONS?
DRAFT 6/13/18