ML20093F016
| ML20093F016 | |
| Person / Time | |
|---|---|
| Site: | Columbia  (NPF-021) |
| Issue date: | 04/06/2020 |
| From: | Ronnie Garcia Energy Northwest |
| To: | Division of Operating Reactor Licensing |
| Klos L, 301-415-5136 | |
| References | |
| Download: ML20093F016 (19) | |
Text
Presubmittal Meeting:
License Amendment Request for One-Time Completion Time Extension to Actions for Inoperable Electrical Distribution Subsystems April 6, 2020
Participants
Richard Garcia - Supervisor, Licensing (presenter)
Desiree Wolfgramm - Manager, Regulatory Affairs
James Darling - Work Control Manager
Mike Pezzetti - Assistant Operations Manager, Operations Support
Keven Van Speybroeck, Manager, Technical Services Engineering
Kevin Eldridge - Supervisor, Engineering
David Clymer - Supervisor, Engineering
Woody Layne - Principle Engineer, PRA 2
Agenda
Purpose
Proposed Change
Reason for Request
System Description
Licensing Basis
License Amendment Request (LAR) Approach
Conclusion
LAR Submittal Schedule
Questions 3
Purpose
Present Energy Northwests approach for a LAR to address contingency actions related to a 10 CFR Part 21 issue which will be addressed in Spring 2021 refueling outage
Explain the basis for this request and provide a summary of the content to be provided in the formal application to ensure NRC staff have the information necessary to appropriately consider this request 4
Proposed Change
Delete an expired note regarding a one-time completion time extension to TS Action 3.8.7.A.1
Add the following note to the TS required Actions 3.8.4.G.1, 3.8.7.A.1 and 3.8.7.B.1 for the remainder of the current operating cycle (Cycle 25) 5
NOTE-------------------
During Cycle 25, a Completion Time of 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> is applicable for replacement of WMA-42-8F1E or its failed starter coil.
Loss of cooling to certain Division 2 Electrical Distribution subsystems may result from starter coil failure due to a defective control power transformers (CPT) supporting Division 2 Vital Island cooling. (reference ML19247C581)
10 CFR Part 21 resolution for this component is to replace WMA-42-8F1E (which includes the CPT) during Spring 2021 outage
Online repair work can be done to replace starter coils or buckets to address emergent failures Replacement coils would be susceptible to failing prior to end of service life due to defective CPTs
Reason for Request
6
In field work requires a minimum of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to replace a starter coil and may extend beyond 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />
Loss of a 125 V DC electrical distribution subsystem allows only 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> for restoration
Loss of a 4160 V AC electrical distribution subsystem allows 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for restoration
Failure to restore in either case would result in follow up actions to be in Mode 3 in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />
Reason for Request
7
Current System Description
Division 2 Critical Switchgear HVAC Continuously operated during all plant modes Maintains temperatures between 55 F and 104 F during normal operation Maintains temperatures within equipment qualification limits during emergency operation mode Removes combustible gases generated by emergency batteries by continuous exhaust of battery rooms (no recirculation) 8
Current System Description
Class 1E Alternating Current Distribution System Class 1E electrical distribution to 3 divisions of 4160, 480, 120/240 and 120/208 Volt buses Ensures AC electrical power supplied to engineered safety features needed to achieve and maintain reactor shutdown for anticipated operational occurences and design basis accidents Single failure proof design; 2 of 3 systems provide power to adequate ESF components for shutdown Division 2 4160 Volt bus SM-8 major loads are RHR B and C trains and Division 2 SW 9
Current System Description
Class 1E Direct Current Distribution System Three 125 VDC divisions and one 250 VDC division Provides control power to the onsite AC emergency power system as well as motive and control power to selected safety equipment Battery chargers supply normal power to DC loads with automatic swap to batteries on charger loss Has sufficient independence and redundancy to perform its safety functions, assuming a single failure Division 2 125 V DC subsystem provides control power to 4160 V (SM-8) and 460 V load centers, emergency lighting, DG-2 auxiliary and control power 10
Current Licensing Basis
LCO 3.8.4 DC Sources Operating Requires 3 divisions of DC subsystems to be operable in Mode 1, 2 and 3 Condition J addresses failure to meet Completion time of Condition G with action to Be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 11
Current Licensing Basis
LCO 3.8.7 Distribution Systems - Operating Requires (in part) Division 1 and 2 125 V DC subsystems and AC subsystems to be operable in Mode 1, 2 and 3 12
Current Licensing Basis
LCO 3.8.7 Distribution Systems - Operating 13
Proposed Licensing Basis Example
LCO 3.8.4 DC Sources Operating Condition J addresses failure to meet Completion time of Condition G with action to Be in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 14
NOTE----------
During Cycle 25, a Completion Time of 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> is applicable for replacement of WMA-42-8F1E or its failed starter coil.
2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />
LAR Approach
Deterministic evaluation with risk insights developed in accordance with Reg Guide 1.177
Considerations for:
actual heatup of critical switchgear impact to station blackout coping analysis defense in depth of AC and DC electrical power systems Removal of combustible battery gasses 15
LAR Approach
Risk Considerations Included in LAR PRA Model adequacy for Full Power Internal Events, Fire and Seismic Models Evaluation of incremental conditional core damage probability (ICCDP) and incremental conditional large early release probability (ICLERP)
Risk Significant Configurations and Insights including weather events and external hazards beyond fire and seismic Configuration Risk Management Program Compensatory Measures 16
Conclusion
Technical evaluations and risk insights establish reasonable assurance that health and safety of the public will not be endangered by proposed limited use completion time extension.
The quantitative results for ICCDP and ICLERP for the CT extension application are less than the guidance thresholds
Further risk reduction will be obtained by additional compensatory measures outlined in a regulatory commitment 17
LAR Submittal Schedule
4/6/2020 - Presubmittal meeting
4/15/2020 - Target LAR submittal
6/15/2020 - Requested approval date 18
NRC Questions 19