ML25248A004
| ML25248A004 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 09/04/2025 |
| From: | Mahesh Chawla Plant Licensing Branch IV |
| To: | Collis T Energy Northwest |
| Chawla M | |
| References | |
| EPID L-2025-LLA-0057 | |
| Download: ML25248A004 (1) | |
Text
From:
Mahesh Chawla To:
Collis, Tracey M.
Cc:
Ahsan Sallman; Michelle Kichline; Norbert Carte; Tarico Sweat; Tony Nakanishi; Nicholas Difrancesco; Andy Patz; Fanta Sacko; Shivani Mehta; Patricia Vossmar; Christopher Highley; Jason Brodlowicz
Subject:
Final Request for Additional Information - Columbia - LAR to Revise Columbia Generating Station TS 3.3.2.1 Control Rod Block Instrumentation - EPID: L-2025-LLA-0057 Date:
Thursday, September 4, 2025 4:37:00 PM Attachments:
RAI-10854-R1-FINAL.docx
Dear Ms Collis,
By application dated March 21-2025 (ADAMS Accession No. ML25083A158), pursuant to Section 50.90 of Title 10 of the Code of Federal Regulations (CFR), Energy Northwest (or the licensee) submitted a License Amendment Request (LAR) for Columbia Generating Station (Columbia).The licenseesproposed amendment would modify Columbias Technical Specification (TS) 3.3.2.1, Control Rod Block Instrumentation, Required Action C.2.1.2, which currently restricts reactor startup with an inoperable rod worth minimizer (RWM) to once per calendar year. The proposed change to the Required Action C.2.1.2 would be to allow additional reactor startups with a new action to verify control rod coupling inspection has been performed prior to a reactor restart.
On August 25, 2025, the NRC staff provided the draft requested additional information, needed to facilitate completion of the technical review of the subject LAR. A clarification teleconference was held with the NRC staff on September 3, 2025. The clarification call did not result in any changes to the draft RAI, and therefore it is retransmitted as the final RAI, attached to this email. During the call, you agreed to provide the response on the docket within 30 days of the receipt of this email. Therefore, we look forward to your official response on the docket. In case of any questions/concerns please reach out to me. Thanks
Mahesh(Mac) Chawla, Project Manager Licensing Branch LPL4 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Phone: (301) 415-8371 Email: Mahesh.Chawla@nrc.gov
1 REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION COLUMBIA - LAR TO REVISE COLUMBIA GENERATING STATION TS 3.3.2.1 CONTROL ROD BLOCK INSTRUMENTATION ENERGY NORTHWEST COLUMBIA GENERATING STATION, UNIT 2 DOCKET NO. 05000397 ISSUE DATE: 09/04/2025
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Background===
By application dated March 21-2025 (ADAMS Accession No. ML25083A158), pursuant to Section 50.90 of Title 10 of the Code of Federal Regulations (CFR), Energy Northwest (or the licensee) submitted a License Amendment Request (LAR) for Columbia Generating Station (Columbia). The licensees proposed amendment would modify Columbias Technical Specification (TS) 3.3.2.1, Control Rod Block Instrumentation, Required Action C.2.1.2, which currently restricts reactor startup with an inoperable rod worth minimizer (RWM) to once per calendar year. The proposed change to the Required Action C.2.1.2 would be to allow additional reactor startups with a new action to verify control rod coupling inspection that has been performed prior to a reactor restart.
Regulatory Basis 10 CFR 50, Appendix A GDC 28, Reactivity Limits, states that The reactivity control systems shall be designed with appropriate limits on the amount and rate of reactivity increase to assure that the effects of postulated reactivity accidents can neither (1) result in damage to the reactor coolant pressure boundary greater than limited local yielding nor (2) sufficiently disturb the core, its support structures or other reactor pressure vessel internals to impair significantly the capability to cool the core. These postulated reactivity accidents shall include consideration of rod ejection (unless prevented by positive means), rod dropout, steam line rupture, changes in reactor coolant temperature and pressure, and cold-water addition.
Question 1 SNSB RAI-1 The LAR enclosure, Section 3.2, fourth paragraph states:
"The inadvertent Operator-initiated withdrawal of a single control rod from the core is classified as a nonlimiting transient event."
Provide responses to the following questions:
Compared to which other transient events during startup it is nonlimiting?
What are the parameters due to which this event is considered nonlimiting?
Question 2 SNSB RAI-2 FSAR Section 7.7.1.2.2.2 Rod Block Trip System, paragraph b.2.(e) states:
2 "The RWM [Rod Worth Minimizer] can initiate a rod insert block and a rod withdrawal block. The purpose of these functions is to reinforce procedural controls that limit the reactivity worth of control rods under lower power conditions. The rod block trip settings are based on the allowable control rod worth limits established for the design basis rod drop accident. Adherence to prescribed control rod patterns is the normal method by which this reactivity restriction is observed."
According to the above description, the RWM system is provided with rod block and rod withdrawal trip settings established for the rod drop accident. In the absence of the RWM system, explain how these trips at the same trip setting in the RWM are accomplished.
Question 3 SNSB RAI-3 For the RWM function to be bypassed or inoperable, its block function would be disabled.
Please confirm that for each startup without RWM, the specific procedural controls a, b, c, and d initiated by the operator listed in FSAR Section 7.7.1.10.2, Operation, will be implemented. In case these controls are changed, provide the revised controls justifying their adequacy.
OFFICE NRR/DORL/LPL4/PM NRR/DORL/LPL4/BC NRR/DSS/SNSB/BC NAME MChawla TNakanishi NDifrancesco DATE 09/04/2025 08/25/2025 08/22/2025