ML18176A042
| ML18176A042 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 06/25/2018 |
| From: | Vaughn S Nuclear Energy Institute |
| To: | Division of Inspection and Regional Support |
| Lewin A, NRR/DIRS, 415-2259 | |
| References | |
| Download: ML18176A042 (20) | |
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
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Outline
- Background
- Purpose
- Proposed Changes
- Overall Process
- Proposed Pilot Effort
- Challenges
- Project Schedule 2
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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
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Purpose
- Provide members 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 Leverage the effectiveness of maintenance strategies and lessons learned from the equipment reliability process
- 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
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Proposed Changes
- Perform causal evaluations commensurate with safety
- All HSS functional failures and Plant Level Events warrant a near real time causal evaluation
- A trend of low safety significant failures warrants an appropriate causal evaluation.
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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 7
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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 effective maintenance strategy (a)(2)
Components that are currently effectively controlled via effective maintenance strategy Perform Maintenance Strategy Execute the defined maintenance strategy 8
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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 SSC and is either a Maintenance Rule Functional Failure (MRFF) or a Condition Monitoring Event (CME) a CAP cause evaluation is performed Yes Yes Yes No 9
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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 to determine adverse trends under the (a)(3) assessment If an adverse trend is identified, a CAP cause evaluation is performed Yes Yes No No 10
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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 No Yes 11
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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 evaluation Both a high-level and detailed assessment of unavailability data Yes No 12
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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
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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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Overall Process - Example #2 Component: Radiation Monitor RU148 (Containment Monitor)
Function: Monitor plant radiological conditions for assessment of site boundary radiation exposure levels Safety Significance: Low
==
Description:==
Monitor taken offline due to excessive spiking and several ALERT alarms - due to apparent electronic interference.
NUMARC 93-01: Third failure against performance criteria of 4 failures in 12 months - remain in (a)(2).
Proposed Process: LSS failure would be slated for review in (a)(3)
Assessment. CAP trending or (a)(3) review could identify or determine adverse trend.
15
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Overall Process - Example #3 Component: Station Battery Function: Provide 125V DC for use in EOPs Safety Significance: HSS
==
Description:==
Failure is unacceptable. Use condition monitoring (i.e., CME). Specific gravity and other parameters are monitored to detect adverse trends and allow corrective actions prior to failure.
NUMARC 93-01: Criteria: 2 CMEs in 24 months.
Proposed Process: Each battery CME has a CAP cause evaluation performed and assess for (a)(1) - (a)(2) 16
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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 are not required to implement the NUMARC 93-01 process in parallel for the systems being piloted
- Pilot starts in 4th quarter 2018 or 1st quarter 2019
- Continued interactions with the staff 17
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Challenges
- Change management
- Impact to other station processes
- Defining responsibilities
- Other efficiencies
- Applicability of current enforcement and inspection guidance
- 50.65 is a performance-based rule 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)
- 1st quarter 2019 - Public meeting to review initial pilot plant results 19
© NEI 2018. All rights reserved. For use by NEI members only.
© NEI 2018. All rights reserved. For use by NEI members only.
QUESTIONS?