ML20279A361
| ML20279A361 | |
| Person / Time | |
|---|---|
| Issue date: | 10/07/2020 |
| From: | Daniel Merzke NRC/NRR/DRO/IRAB |
| To: | |
| Daniel Merzke NRR/DRO/IRAB, 4251457 | |
| References | |
| Download: ML20279A361 (15) | |
Text
Graded Approach in Inspection Dan Merzke U.S. Nuclear Regulatory Commission
Inspection Oversight framework 2
Inspection
- Step 1-Identify activities, structures, systems, and components (SSCs) that are important to safety.
- License application
- FSAR
- Probabilistic Safety Analyses (NPPs)
- Inspection experience
- Operating experience - historical problems 3
Inspection
- Step 2 - Determine which factors are applicable to the decision
- type of facility (PWRs have different ISI requirements)
- Stage in life cycle (construction inspection requirements differ from operations inspections
- Operating experience - focus inspections on areas where safety-significant SSCs have a higher failure probability, informing the sample size requirements for inspections of licensee surveillances.
- Inspector experience
- Special and infrequently performed activities 4
Inspection
- Step 3 - Integrate the applicable factors into the determining the optimal resource effort required to ensure licensees are operating their facilities in a manner that protects public health and safety, and the environment. Regulator determines the appropriate inspection sample size and frequency.
- Baseline inspection program - minimum inspection to assure licensee performance satisfies cornerstone objectives. (What to inspect, frequency of inspection, how to inspect) 5
Inspection
- Process described in SECY-99-007.
- Risk Information Matrices (RIMs) developed in determining which activities, systems, or components are to be inspected in the baseline inspection program.
- Each cornerstone has several attributes from which the inspectable areas are derived. These inspectable areas were selected based on their risk significance 6
Inspection 7
- RIM
Inspection
- Sample size and number of hours were developed based on expert judgement and relevant risk information on how much inspection activities would be sufficient to ensure verification that the licensee was meeting the objectives of all seven cornerstones.
- IMC 0308, Attachment 2, Technical Basis for Inspection Program, documents scope and basis for each inspectable area.
8
Inspection Based on Performance 9
- Graded approach to inspection based on performance
- As performance declines, inspection increases
- Described by Action Matrix
Action Matrix Concept Increasing safety significance Increasing NRC inspection efforts Increasing NRC/licensee management involvement Increasing regulatory actions Column 1 Column 2 Column 3 Column 4 Column 5 10 Licensee
Response
Regulatory
Response
Degraded Performance Multiple/Repetitive Degraded Cornerstone Unacceptable Performance
Inspection Based on Performance 11
- Step 1 - identify SSCs important to safety
- Focus on activity or SSC where performance is deficient
- Step 2 - determine which factors applicable
- Safety significance of deficiency
- Isolated vs site-wide (extent of condition)
- Step 3 - integrate factors to determine optimal resource effort
- Scope of inspection effort described in supplemental inspection procedures based on number and/or safety significance of performance deficiencies and performance indicators
Inspection Based on Performance 12
- Supplemental Inspections
- Column 2 - IP 95001 supplemental inspection (40-120 hours)
- Column 3 - IP 95002 supplemental inspection (200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br />)
- Column 4 - IP 95003 supplemental inspection (3000 hours0.0347 days <br />0.833 hours <br />0.00496 weeks <br />0.00114 months <br />) -
diagnostic inspection
References
- IMC 0305, Operating Reactor Assessment Program
- IMC 0308, Attachment 2, Technical Basis for Inspection Program
- IMC 2515, Light-Water Reactor Inspection Program
- Inspection Procedure 95001, Supplemental Inspection Response to Action Matrix Column 2 Inputs
- Inspection Procedure 95002, Supplemental Inspection for One Degraded Cornerstone or Any Three White Inputs in a Strategic Performance Area
- Inspection Procedure 95003, Supplemental Inspection for Repetitive Degraded Cornerstones, Multiple Degraded Cornerstones, Multiple Yellow Inputs or One Red Input 13
Inspection CORNERSTONE INSPECTION HOURS PER YEAR (2-UNIT SITE*)
Initiating Events 182 Mitigating Systems 1151 Barrier Integrity 183 Emergency Preparedness 88 Occupational Radiation Exposure 123 Public Radiation Exposure 40 Physical Security 244 Total 2011 14
Action Matrix 15