ML24296B165
| ML24296B165 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 10/22/2024 |
| From: | Justin Poole Licensing Processes Branch, Plant Licensing Branch III |
| To: | Entergy Nuclear Operations |
| Wall S | |
| References | |
| GSI191 | |
| Download: ML24296B165 (1) | |
Text
www.holtec.com Pre-Submittal Meeting Palisades Nuclear Plant GL 2004-02 / GSI-191 Closure Plan October 24, 2024
www.holtec.com l Page 2 Meeting Agenda
Introductions
Purpose & Outcome
Background
Closure Plan Closure Plan Submittal Content Schedule Questions
www.holtec.com l Page 3
Introductions
U.S Nuclear Regulatory Committee (NRC) Staff Holtec Decommissioning International, LLC (HDI)
Jean Fleming - Holtec International, Vice President of Licensing and Regulatory Affairs Jim Miksa - HDI, Regulatory Assurance Manager for Palisades Joe Jerz - HDI, Engineering Director ENERCON Tim Sande - PRA Manager, GSI-191 SME Kyle Reno - Chief Mechanical Supervisor Blake Stair (Remote Participant) - Chemical Effects SME Haifeng Li (Remote Participant) - EG Mechanical Supervisor, GSI-191 SME
www.holtec.com l Page 4 Purpose & Outcome
Purpose:
- Inform NRC of Palisades Nuclear Plant (PNP) plans to resume work on GL 2004-02 Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors
- Provide a summary of PNP GL 2004-02 / GSI-191 activities completed prior to cessation of power operations
- Present key elements of PNP GL 2004-02 closure plan Outcome:
- Solicit NRC Staff questions and comments on proposed closure plan
- Provide schedule information to support NRC resource allocation
www.holtec.com l Page 5 Palisades Design
- 2 Loop Combustion Engineering Nuclear Steam Supply System (NSSS)
- Sodium Tetraborate (NaTB) Buffer
- Debris screens installed at inlets to the containment sump
- Passive debris strainers installed at Emergency Core Cooling System (ECCS) inlet to containment sump
Background
www.holtec.com l Page 6 6
NaTB Baskets NaTB Baskets Strainer Modules A, B Strainer Modules C, D Containment Ground Level - 590 El.
Background
Containment Sump Suction source for ECCS pumps for recirculation phase post-Loss Of Coolant Accident (LOCA)
www.holtec.com l Page 7
Background
2004 - NRC issues GL 2004-02 Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors (ML042360586)
2007 - Changed the sump buffering agent from TSP to Sodium Tetraborate (NaTB)
Decrease the magnitude of chemical precipitates
2007 - Replaced the high-pressure safety injection (HPSI) pump mechanical seals and cyclone separators (ML13136A006)
Components not susceptible to premature failure due to fibrous debris
2007 - Installed passive debris screens on containment sump downcomers, containment floor drains, and containment sump vent lines (ML13136A006)
Mitigate post-LOCA generated debris entry into the containment sump envelope
2009 - Installed passive sump strainer assemblies with 0.095 hole size at ECCS pump suction inlet to containment sump (ML13136A006)
www.holtec.com l Page 8
Background
2013 - PNP selected the risk-informed approach to GSI-191 closure (ML13136A006)
Similar approach to South Texas Project, the risk informed pilot plant for GL 2004-02 / GSI-191 closure activities
March 2018 PNP Delivered GSI-191 (GL 2004-02) Milestone Schedule (ML18088A139)
Projected closure date February 2022
2018 - Modified the containment sump vents to enhance sump performance (ML19064A089)
March 2019 PNP notified NRC stopping work on GSI-191 closure efforts due to early permanent shutdown for decommissioning (ML19064A089)
www.holtec.com l Page 9
Background
March 2024 - Conducted scoping study to identify viable options for responding to GL 2004-02 / GSI-191
Used most recent industry operating experience
Utilized ENERCON as subject matter experts due to their recent involvement in other utilities GL 2004-02 closure responses August 2024 - Completed third-party independent review of ENERCON scoping study
Utilized Westinghouse to independently validate recommended closure plan
Westinghouse team was actively involved in industry closure guidance including WCAP-17788-P Comprehensive Analysis and Test Program for GSI-191 Closure
www.holtec.com l Page 10 Closure Plan
The below closure options were considered when determining the recommended strategy for resolving GL 2004-02 Deterministic resolution
Significant amount of high worker dose insulation replacement required
Bounding tests and calculations
GL 2004-02 response submittal Alternate break resolution
Bounding assessment for alternate break size
Relaxed assessment for larger breaks
GL 2004-02 response submittal Risk-informed resolution
Risk over Deterministic (RoverD) approach
Conditional failure probability (CFP) approach
Threshold break approach
Any of the approaches above require a LAR and a request for exemption from certain requirements in 10 CFR 50.46
www.holtec.com l Page 11 Closure Plan The CFP risk informed approach was selected for PNP based on:
Most accurately evaluates PNP post-LOCA conditions
Similar approach as Vogtle and Point Beach for successful resolution to GL 2004-02 After updating key GSI-191 calculations and tests, HDI will assess if the alternate break methodology can be used to evaluate PNP post LOCA conditions Deterministic approach was not selected due to the worker dose associated with a significant amount of insulation replacement
www.holtec.com l Page 12 Closure Plan In-Vessel Effects to be resolved using industry guidance
PWROG-16793-P Evaluation of Long-Term Colling Considering Particulate, Fibrous and Chemical Debris in the Recirculating Fluid
WCAP-17788-P Comprehensive Analysis and Test Program for GSI-191 Closure PNP will consider industry operating experience used by other licensees to inform the results of the overall GL 2004-02 / GSI-191 assessment
Use another licensees results from previously conducted penetration tests on PCI strainers with an identical 0.095-inch hole size
Chemical precipitate timing for in-vessel effects (tchem) will be assumed at 8 hr per PWROG-16073-P and WCAP-17788-P
www.holtec.com l Page 13 Closure Plan Major milestones for closure
Develop/update initial GSI-191 calculations (debris generation, transport, chemical effects)
Conduct strainer head loss testing
Determine if Alternate Break resolution is viable for PNP
Develop/update follow-on GSI-191 calculations (strainer structural qualification, in-vessel effects, PRA inputs, risk/uncertainty quantification)
Submit GL 2004-02 response
www.holtec.com l Page 14 Closure Plan Submittal Content GL-2004-02 Closure Actions Taken to Date Summary of Reinstated Closure Plan Key Reference Documents Commitments to be reinstated in accordance with NEI 99-04, Guidelines for Managing NRC Commitments, coincident with transition to power operations licensing basis Provide Closure Plan Schedule
www.holtec.com l Page 15 Schedule Milestone Date Submit Updated GL 2004-02 Closure Plan to NRC 4Q2024 Develop/update GSI-191 calculations (debris generation, transport, chemical effects) 2Q2025 Conduct strainer testing (head loss, penetration) 3Q2025-4Q2025 Decision Point - Use of CFP or Alternate Break approach 1Q2026 Finalize GSI-191 calculations (strainer structural qualification, in-vessel effects, PRA inputs, risk/uncertainty quantification) 2Q2026 Submit Final Response and Close-out to GL 2004-02 2Q2026
www.holtec.com l Page 16 Thank You Krishna P. Singh Technology Campus 1 Holtec Boulevard Camden, NJ 08104 Tel: (856) 797-0900 www.holtec.com