ML21144A017

Spent Fuel Pool Cooling - Shutdown Cooling Licensing Design Basis License Amendment Request Pre-Submittal Meeting

ML21144A017
Person / Time
Site:	Calvert Cliffs
Issue date:	05/24/2021
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
Marshall M, NRR/DORL/LPLI, 415-2871
References
Download: ML21144A017 (16)

Text

Calvert Cliffs Nuclear Power Plant Spent Fuel Pool Cooling - Shutdown Cooling Licensing Design Basis License Amendment Request Pre-submittal Meeting NRC Pre-submittal Meeting Telecon May 24, 2021

Agenda / Opening Remarks

• Introductions

• Expected outcome of meeting

• LAR Overview / Purpose

• Regulatory Requirements

• Technical Evaluation

• Precedent

• LAR Milestone Schedule

• Closing Remarks 1

Introductions

• Frank Mascitelli, Lead Licensing Engineer

• Ken Greene, Site Regulatory Engineer

• Larry Smith, Manager Site Regulatory Assurance

• Dave Helker, Senior Manager Licensing

• Mohammad Ghaderi- Yeganeh, LAR Technical Lead

• Cecilie Broussard, SFPC Strategic Engineer

• John Singleton, Operations Senior Reactor Operator

• Chris Junge, Manager Engineering

• Chris Jackson, Senior Manager Outages

• John Massari, Manager Nuclear Fuels

• Eric Yin, Senior Staff Fuel Engineer

• Kurt Bodine, Manager Engineering Lead 2

Expected Outcome of Meeting

• NRC gains an understanding of the LAR and provides feedback for CCNPP, so that a timely six-month review can be accomplished in support of Feb 2022 U/1 refueling outage.

• Critical issues are identified early.

• All required regulatory and technical requirements are identified.

• Ensure a successful Acceptance Review and minimize significant Request for Additional Information (RAI) cycles.

3

LAR Overview / Purpose

• The proposed changes would revise the Updated Final Safety Analysis Report (UFSAR) Section 9.4, Spent Fuel Pool Cooling System, design basis to allow for a full core offload without being supplemented with one loop of Shutdown Cooling (SDC) system, if needed.

• In addition, the Technical Requirements Manual (TRM) 15.9.1, Decay Time, will be revised to provide for additional limits on operation based on nuclear fuel decay time, service water temperature and SFP bulk temperature.

• Be able to support outage work using only two operating SFPC trains and no train of SDC to support SFPC, while keeping the overall outage length within schedule.

4

LAR Overview / Purpose

• During the next 2022 Unit 1 Refuel Outage (CC1R 26) which is planned to start early February 2022, a full core off load is scheduled to begin approximately day 6 of the Outage.

• One loop of SDC is required operable and in operation per TS 3.9.4, Shutdown Cooling (SDC) and Coolant Circulation-High Water Level. The second SDC loop will be out of service for scheduled outage work (ASME OM Code required).

• This course of action without the additional heat removal capabilities of the supplemental loop of shutdown cooling may cause the spent fuel pool temperature to rise above current licensing bases limit of 130 °F.

5

Regulatory Requirements

• 10 CFR 50.36, Technical Specifications

• 10 CFR 50 Appendix A, General Design Criterion (GDC) 61, Fuel Storage and Handling and Radioactivity Control

• 10 CFR 50 Appendix A, General Design Criterion 44, Cooling Water

• Regulatory Guide (RG) 1.13 Rev 2, Spent Fuel Pool Storage Facility Design Basis

• NUREG 0800, Standard Review Plan (SRP) 9.1.3 Spent Fuel Pool Cooling and Cleanup System 6

Regulatory Requirements

• Embedded in existing regulatory requirements is that existing instantaneous spent fuel pool cooling always exceeds the instantaneous spent fuel decay heat rate.

LAR will allow cooling capacity to be exceeded and pool bulk temperature to rise.

• Will exceed RG 1.13, Spent Fuel Storage facility Design Bases, Rev 2 limit of 140 °F.

- The maximum allowed Spent Fuel Pool water temperature may be up to 150 °F for all heat load conditions, including full-core offloads during refueling.

7

Technical Evaluation

• Obtain margin in heat removal capability by raising the maximum SFP water temperature for 2022 full core offload from 130 °F to 150 °F (the design temperature of SFP cooling system)

• Methodology change to start crediting the time it takes for the bulk SFP water to heat up to 150 °F

• Develop time dependent heat transfer model to calculate the maximum SFP temperature 8

Technical Evaluation

• Impact on the design of the SFP cooling system /

purification system

• Analyze the time-to-boil using representative refueling practices and identify make-up water sources

• Structural integrity of the SFP and impact of raising SFP temperature to 150 °F. The impact is bounded by the existing analysis.

• The impact of SFP temperature rise on the criticality is bounded by the existing analysis.

9

Technical Evaluation

• The radiological consequences during a fuel handling event are within acceptable dose criteria specified in 10CFR50.67 including control room operator dose. The impacts are bounded by the existing radiological analysis.

10

Technical Evaluation 11

Precedent

• Turkey Point Units 3 and 4 - Issuance of Amendments Regarding Reduction in Decay Time from 100 to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (TAC NOS. MB6549 AND MB6550), dated March 4, 2003 (ML0306207460), provides relevant insights and review criteria as the reduction in decay time resulted in an increase in heat load to the SFPC system and SFP bulk temperature.

• Calvert Cliffs Units 1 and 2 TS Amendment Nos. 47 and 30, respectively, permitted an increase in the spent fuel storage capability up to a maximum of 1760 fuel assemblies in the spent fuel pool through the use of high density borated spent fuel racks, dated September 19, 1980 (ML003773029). Section 3.2 (Spent Fuel Cooling) of the Safety Evaluation Report provides relevant insights and review criteria for original licensing design bases for the SFPC System.

12

LAR Milestone Schedule

• Pre-submittal meeting 05/24/21

• PORC (Plant Operations Review Com.) 06/11/21

• Submit LAR to NRC 06/15/21

• Requested approval date 12/17/21 13

Closing Remarks

• Additional Questions/Observations

• Summarize critical insights

• Next Steps 14

Thank you 15