ML20125A336
| ML20125A336 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 05/04/2020 |
| From: | Dennis Galvin NRC/NRR/DORL/LPL4 |
| To: | |
| Dennis Galvin - NRR/DORL 301-415-6256 | |
| References | |
| L-2020-LRM-0039 | |
| Download: ML20125A336 (9) | |
Text
Pre-Submittal Meeting on Proposed Exigent LAR Regarding Accumulator Pressures for Unit 1 Cycle 23 May 5, 2020
STP Participants
- Lance Sterling, Regulatory Affairs Manager
- Jason Tomlinson, Plant Engineering Manager
- Drew Richards, Licensing Supervisor
- Safdar Hafeez, Reactor Analysis Engineer
- Roland Dunn, Engineering General Manager
- Fatma Yilmaz, NF&A Manager
- Jeff Atkins, Operations Manager 2
Discussion Topics Problem Description Proposed License Amendment Preliminary Technical Evaluation Planned Submittal Schedule 3
Problem Description
- Leakage identified on Safety Injection (SI) Train 1A following startup from recent Unit 1 refueling outage
- Water and nitrogen leaking from Accumulator 1A to RHR/LHSI discharge header through check valve RH-0032A
- Maintaining volume and pressure requires frequent RHR venting and refilling of SI Accumulator 1A
- Challenge to safety-related components due to component cycling
- Lowering pressure of all accumulators to less than RHR relief valve pressure will eliminate need for cycling safety-related components 4
Proposed License Amendment Modify TS 3/4.5.1, Accumulators to allow Unit 1 to operate with all three Safety Injection (SI) System Accumulators at reduced pressure Add note to TS Surveillance Requirement 4.5.1.1 to reduce the lower pressure limit for the accumulator nitrogen cover-pressure from 590 psig to 500 psig through the end of the next refueling outage Resolves valve leakage issue while maintaining all three SI accumulators operable and having no significant adverse impact to the RHR or Low-Head Safety Injection (LHSI) systems One-time change would support deferral of repairs until the next Unit 1 refueling outage Need for exigency - necessary to avoid a reactor shutdown without a commensurate increase in safety 5
Preliminary Technical Evaluation Large-Break LOCA Peak Clad Temperature (PCT) impact Containment Analysis Peak Pressure impact Large Break LOCA limiting Containment Analysis Peak Temperature impact Main Steam Line Break limiting Containment Equipment Qualification Peak Pressure and Temperature Containment subcompartment analysis Leak-Before-Break (LBB) methodology Post-LOCA hot leg recirculation switchover time Plan to evaluate small break LOCA, post-LOCA long-term cooling and subcriticality, Main Steam Line Break Hot Zero Power DNBR analysis 6
Planned Submittal Schedule SI Accumulator 1A isolated on April 29, 2020 STP will receive results of analysis from vendor on May 11, 2020 Planned amendment request submittal on May 14, 2020 Approval of the amendment requested by May 28, 2020 Amendment will be implemented prior to the expiration of the Risk-Informed Completion Time on May 29, 2020 7
Questions?
8