ML20007D677
| ML20007D677 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 01/08/2020 |
| From: | Jeffrey Bream NRC/NRR/DRO/IRIB |
| To: | |
| Bream J, 610-337-5212, NRR/DRO | |
| References | |
| Download: ML20007D677 (14) | |
Text
Reactor Oversight Process (ROP) for Inspecting Vogtle Site with AP1000 Design January 14 and 22, 2020 Public Meetings 1
The AP1000 passive design provides overall safety enhancements.
2 Image of AP1000' - Westinghouse Nuclear The above illustration is an artist rendering and may not depict actual design and layout Passive versus Active Components AC is not required for safe shutdown Elimination of safety-related motor operated valves Elimination of AC powered safety-related pumps Simpler Design - no need for human interaction for the first 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Uses natural forces such as gravity, convection and condensation cooling
Simpler design results in the need for an inspection sample range reassessment.
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- 50% fewer safety-related valves
- 35% fewer pumps
- 80% less safety related piping
- 85% less control cable
- 45% less seismic building volume
NRC Performance Goals
- Safety: Ensure adequate protection of public health and safety and the environment.
- Security: Ensure adequate protection in the secure use and management of radioactive materials.
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Reactor Oversight Process Safety Cornerstones Baseline Inspection Results Significance Threshold Action Matrix Significance Threshold Performance Indicator Results Regulatory Response Strategic Performance Areas Safety Cornerstones Baseline Inspection Results Significance Threshold Action Matrix Significance Threshold Performance Indicator Results Regulatory Response Strategic Performance Areas 5
The Cornerstones have supporting inspections.
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Inspection oversight for Units 3 and 4 considers current inspection at Units 1 and 2 7
U 3
4 U
1 2
Image of Vogtle 1-4, Waynesboro Georgia - Georgia Power, A Southern Company http://www.multivu.com/players/English/7464951-ga-power-project-vogtle/
8 NRC used a three step process to determine proposed sample sizes.
- Began with the current Minimum, Nominal, and Maximum sample sizes and existing guidance for sample size adjustment for conventional plants in all procedures.
Current Sample
- Assess unique aspects of the passive technology
- Overall component numbers and accessibility.
New Technology
- Assess for common programs across the site due to colocation with conventional plant.
Evaluate Common Programs
Inspection procedures are either individual or site wide, and samples were addressed accordingly.
Procedure Category Sample Size Analysis Individual Reactor Safety Baseline Inspection Procedures (BIPs)
Staff used technology specific component analysis and risk information inherent from the design of the two AP1000 units to develop sample size ranges in accordance with Inspection Manual Chapter 2515 Common Site-Wide Program BIPs Staff evaluated and adjusted, if necessary, the maximum sample size to provide an adequate number of samples across the two different designs 9
Example of changes to BIPs which are conducted on 2-Unit PWR and 2-Unit AP1000 independently.
IP 71111.22 Surveillance Testing - Design Specific 17 7
BIP Nominal Samples Current 2-Unit AP1000 2-Unit IP 71111.11 Licensed Operator Requalification and Performance - Design Independent 8
8 BIP Nominal Samples Current 2-Unit AP1000 2-Unit 10
Example of BIPs which are conducted as 4 unit site:
Vogtle Site Common Engineering Inspections.
71111.21N.02 Design Basis Capability of Power Operated Valves
- Current BIP sample range is 8-12 for existing units
- Staff assessment of AP1000 identified BIP sample range of 3-5
- Increase BIP sample maximum to 16 samples for Vogtle site with samples from all 4 units.
71111.21M Design Basis Assurance
- Will require separate samples from Units 1&2 and Units 3&4 but existing maximum sample size is sufficient to account for all units.
- Vogtle inspection at maximum sample size.
- No change to baseline inspection.
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The staff has identified the number of samples for U3&4 based on the number of AP1000 components, risk characteristics, and co-location on an existing site.
Individual BIP Site Wide BIP 181 51 Nominal Inspection Samples for Units 1&2 Individual BIP Site Wide BIP 79 25 Additional Nominal Inspection Samples for Units 3&4 12 Subject to additional NRC evaluation of Vogtle Site organizational structure for the applicable programs.
The NRC review identified appropriate modifications to the baseline inspection program for the Vogtle site.
- The three step process considered current baseline, passive design, and co-location with an operating reactor.
- Appropriate sample sizes were identified for each inspection procedure to establish reasonable assurance of adequate protection.
- NRC identified inspection procedures for individual and site wide implementation.
Questions?
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Reference Sources
- Reactor Oversight Process
- https://www.nrc.gov/reactors/operating/oversight.html Public Electronic Reading Room
- http://www.nrc.gov/reading-rm.html Public Document Room 800-397-4209 (Toll Free) 14