ML25072A273
| ML25072A273 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 03/13/2025 |
| From: | John Klos Plant Licensing Branch II |
| To: | Virginia Electric & Power Co (VEPCO) |
| Klos, J | |
| References | |
| Download: ML25072A273 (1) | |
Text
1 REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SURRY UNITS 1 AND 2, ALT RELIEF REQUEST MECHANICAL AGITATION ACCUMULATOR CHECK VALVE VIRGINIA ELECTRIC AND POWER COMPANY SURRY, UNITS 1, 2 DOCKET NO. 05000280, 05000281 ISSUE DATE: 03/13/2025 These RAIs are officially issued today and a response is required in 30 calendar days on April 13, 2025.
Question 1
Background:
By letter dated December 30, 2024, Virginia Electric and Power Company (Dominion Energy Virginia) (Agencywide Documents Access and Management System (ADAMS), Accession ML24365A198submitted Alternative Request V-2 for authorization by the U.S. Nuclear Regulatory Commission (NRC), pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(2), to implement an alternative to the inservice testing (IST) requirements of the 2020 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code), as incorporated by reference in 10 CFR 50.55a, associated with certain accumulator discharge check valves at Surry Power Station (SPS), Units 1 and 2.
Regulatory Basis:
The NRC regulations in 10 CFR 50.55a(z), " Alternatives to codes and standards requirements
," states that :
"Alternatives to the requirements of paragraphs (b) through (h) of this section or portions thereof may be used when authorized by the Director, Office of Nuclear Reactor Regulation. A proposed alternative must be submitted and authorized prior to implementation. The applicant or licensee must demonstrate that:
(1) Acceptable level of quality and safety. The proposed alternative would provide an acceptable level of quality and safety; or (2) Hardship without a compensating increase in quality and safety. Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety."
Requests for Additional Information (RAIs):
EMIB-RAI-1 In the licensee's Alternative Request V-2, the licensee has requested, in Section 7.0, "Duration of Proposed Alternative," a duration for the Sixth and Seventh Inservice Testing Interval, for this proposed alternative to the ASME OM Code IST requirements.
2 Please clarify that the duration of the proposed alterative is for the remainder of the Sixth IST interval and the Seventh IST interval for the Code of Record Interval at SPS, Units 1 and 2, that uses the 2020 Edition of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a EMIB-RAI-2 In its letter dated December 30, 2024, the licensee specifies the back leakage and closure testing requirements.
Please clarify (1) the testing requirements for the check valves within the scope of the alternative request, (2) when closure tests are required, and (3) the type of testing included in Tables V-2.1, "Testing History of Unit 1 Valves (gpm)" and V-2.2 "Testing History of Unit 2 Valves (gpm)," of the alternative request.
EMIB-RAI-3 In its letter dated December 30, 2024, the licensee describes its proposed Alternative Request V-2 describes the requirements for, and the evaluation of, the proposed mechanical agitation of check valves. In its submittal the licensee describes the precedent in the NRC approval dated August 12, 2024 (ML24164A001), concerning Alternative Request V-1.
The NRC staff has reviewed the differences between these two alternative requests and requests the following information concerning Alternative Request V-2 mechanical agitation:
- 1. Please describe the hammer to be used indicated if it is to be rounded or flat-faced hammer.
- 2. Please describe the plan to assure that the mechanical agitation process does not cause adverse or detrimental effects to the valves.
- 3. Please describe any vendor communication regarding the proposed agitation and precautions with the vendor Anchor Darling.
- 4. Please discuss if a proposed common evaluation is applicable for both Anchor Darling and Velan valves.
The licensee is requested to clarify these and any other differences between the requirements for, and the evaluation of, the proposed mechanical agitation of the applicable valves for Alternative Requests V-1 and V-2.
EMIB-RAI-4 In its letter dated December 30, 2024, the licensee describes the valve configuration and structure as being conservative and sights a TVA comparison. The NRC staff notes that a 12-inch swing check valve resulted in a 29-inch valve length for Alternative Request V-2, while the method described in Alternative Request V-1 resulted in a 22-inch valve length for a 6-inch swing check valve. Please describe any variations in the valve length as compared to the V-1 approval as part of the procedural methods to be implemented under Alternative Request V-2 at SPS, Units 1 and 2.
OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/BC NRR/DEX/EMIB/BC NAME JKlos MMarkley SBailey
3 DATE 03/13/2025 03/13/2025 03/06/2025