ML24100A784
| ML24100A784 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 04/09/2024 |
| From: | John Lamb NRC/NRR/DORL/LPL2-1 |
| To: | Lowery K Southern Nuclear Operating Co |
| References | |
| L-2023-LLR-0016 | |
| Download: ML24100A784 (3) | |
Text
From:
John Lamb Sent:
Tuesday, April 9, 2024 2:23 PM To:
Lowery, Ken G.
Cc:
Joyce, Ryan M.
Subject:
For Your Action - Request for Additional Information (RAI) - Vogtle, Units 3 and 4 - Alternative Request for Explosively Actuated Valves (L-2023-LLR-0016)
- Ken, By letter dated February 15, 2024 (Agencywide Documents and Access Management System Accession No. ML24046A230), Southern Nuclear Operating Company (SNC, the licensee) submitted a request for relief from, and authorization to use an alternative to, the requirements of Title 10, Code of Federal Regulations (10 CFR) Section 50.55a(f) in accordance with 10 CFR 50.55a(f)(6), and the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) testing and replacement interval requirements for the squib (explosively actuated) valves in OM Code, Subsection ISTC, paragraph ISTC-5260(c) and ISTC-5260(e)(4). SNC stated that the proposed alternative would allow for no testing or replacement of the squib valve pyrotechnic charges during the first refueling outages (RFOs) for Vogtle Electric Generating Plant (Vogtle), Unit 3 and Unit 4, with increased testing and replacement during the second RFOs for Vogtle, Units 3 and 4.
The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the letter dated February 15, 2024, and determined that additional information is needed to complete its review.
On April 1, 2024, the NRC staff provided the below draft request for additional information (RAI) as draft to SNC to ensure that the RAI were understandable, the regulatory basis was clear, there was no proprietary information, and to determine if the information was previously docketed. A clarifying call was held on April 9, 2024. SNC said that it would respond to the below RAIs in 30 days.
If you have any questions, please contact me at (301) 415-3100.
Thanks.
John REQUEST FOR ADDITIONAL INFORMATION (RAI):
By letter dated February 15, 2024 (Agencywide Documents and Access Management System Accession No. ML24046A230), Southern Nuclear Operating Company (SNC, the licensee) submitted a request for relief from, and authorization to use an alternative to, the requirements of Title 10, Code of Federal Regulations (10 CFR) Section 50.55a(f) in accordance with 10 CFR 50.55a(f)(6), and the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) testing and replacement interval requirements for the squib (explosively actuated) valves in OM Code, Subsection ISTC, paragraph ISTC-5260(c) and ISTC-5260(e)(4). SNC stated that the proposed alternative would allow for no testing or replacement of the squib valve pyrotechnic charges during the first refueling outages (RFOs) for Vogtle Electric Generating Plant (Vogtle), Unit 3 and Unit 4, with increased testing and replacement during the second RFOs for Vogtle, Units 3 and 4.
In its letter dated February 15, 2024, SNC requests relief under 10 CFR 50.55a(f)(6) from the regulatory requirement to perform sample testing of squib valve charges in ASME OM Code, Subsection ISTC, paragraph ISTC-5260(c) and (e)(4), at the next RFOs for Vogtle, Units 3 and 4, as impractical. From the subject SNC letter, it is not apparent that there is sufficient basis for NRC to review the request on the basis that the OM Code is impractical. The NRC staff will, however, review the request under 10 CFR 50.55a(z)(2) as a hardship based on SNCs stated position that the charges required to perform the tests are not available for use the next RFO.
REGULATORY EVALUATION Regulations The regulation in 10 CFR 50.55a, Codes and standards, Section (f), Preservice and inservice testing requirements, Paragraph (6), Actions by the Commission for evaluating impractical and augmented IST Code requirements, states:
(i)
Impractical IST requirements: Granting of relief. The Commission will evaluate determinations under paragraph (f)(5) of this section that code requirements are impractical. The Commission may grant relief and may impose such alternative requirements as it determines are authorized by law, will not endanger life or property or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
(ii)
Augmented IST requirements. The Commission may require the licensee to follow an augmented inservice test program for pumps and valves for which the Commission deems that added assurance of operational readiness is necessary.
The regulation 10 CFR 50.55a(f)(5), Requirements for updating IST programs -, states:
(i)
IST program update: Applicable IST Code editions and addenda. The inservice test program for a boiling or pressurized water-cooled nuclear power facility must be revised by the licensee, as necessary, to meet the requirements of paragraph (f)(4) of this section.
(ii)
IST program update: Conflicting IST Code requirements with technical specifications. If a revised inservice test program for a facility conflicts with the technical specifications for the facility, the licensee must apply to the Commission for amendment of the technical specifications to conform the technical specifications to the revised program. The licensee must submit this application, as specified in § 50.4, at least 6 months before the start of the period during which the provisions become applicable, as determined by paragraph (f)(4) of this section.
(iii)
IST program update: Notification of impractical IST Code requirements. If the licensee has determined that conformance with certain Code requirements is impractical for its facility, the licensee must notify the Commission and submit, as specified in § 50.4, information to support the determination.
(iv)
IST program update: Schedule for completing impracticality determinations. Where a pump or valve test requirement by the Code or addenda is determined to be impractical by the licensee and is not included in the revised inservice test program (as permitted by paragraph (f)(4) of this section), the basis for this determination must be submitted for NRC review and approval not later than 12 months after the expiration of the initial 120-month interval of operation from the start of facility commercial operation and each subsequent 120-month interval of operation during which the test is determined to be impractical.
The regulation 10 CFR 50.55a(z), Alternatives to codes and standards requirements, state:
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.
ASME Code Requirements The first IST interval for Vogtle, Units 3 and 4, began on April 1, 2023, and ends on March 30, 2033. The applicable ASME Code for Vogtle, Units 3 and 4, is ASME OM Code, 2012 Edition.
The ASME OM Code ISTC-5260(c), Explosively Actuated Valves, states:
At least 20% of the charges in explosively actuated valves shall be fired and replaced at least once every 2 years.
The ASME OM Code ISTC-5260(e)(4), states:
For the valves selected in the test sample for subparagraph ISTC-5260(c), the sampling must select at least one explosively actuated valve from each redundant safety train every 2 yr. Each sampled pyrotechnic charge shall be tested in the valve or a qualified test fixture to confirm the capability of the charge to provide the necessary motive force to operate the valve to perform its intended function without damage to the valve body or connected piping.
RAIs Additional information is needed for the U.S. Nuclear Regulatory Commission (NRC) to complete its review. Please provide following information:
- 1. Justify that the alternative request satisfies the provisions of 10 CFR 50.55a(z)(2), which are as follows:
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.
Describe the hardship associated with satisfying the ASME OM Code requirements as incorporated by reference in 10 CFR 50.55a at the next RFO for Vogtle, Units 3 and 4, and justify that meeting those ASME OM Code requirements at that time will not provide a compensating increase in the level of quality and safety.
- 2. Describe the plan to meet the other requirements of ASME OM Code, Subsection ISTC, paragraph ISTC-5260(e), and any adjustments related to compliance with those requirements that might be necessary from a plant and personnel safety perspective in light of the request to not remove and test any charges in the squib valves in the first RFO for each unit.
- 3. The first IST Program interval for Vogtle, Units 3 and 4, began on April 1, 2023, and is scheduled to end on March 30, 2033. For this first IST Program interval, the applicable IST Code of Record for Vogtle, Units 3 and 4, is ASME OM Code, 2012 Edition, as incorporated by reference in 10 CFR 50.55a.
The ASME OM Code, Subsection ISTC, paragraph ISTC-5260(c), Explosively Actuated Valves, states:
At least 20% of the charges in explosively actuated valves shall be fired and replaced at least once every 2 years.
The ASME OM Code, Subsection ISTC, paragraph ISTC-5260(e)(4), states:
For the valves selected in the test sample for subparagraph ISTC-5260(c), the sampling must select at least one explosively actuated valve from each redundant safety train every 2 yr. Each sampled pyrotechnic charge shall be tested in the valve or a qualified test fixture to confirm the capability of the charge to provide the necessary motive force to operate the valve to perform its intended function without damage to the valve body or connected piping.
In its letter dated February 15, 2024, SNC said that it plans to test and replace 100 percent of the squib valve explosive charges within the second 2 years of the First IST Program Interval, and SNC plans to test and replace 50 percent of the charges following the second two-year period.
SNC stated that the duration of the proposed alternative request is from initial reactor criticality through the end of the second RFO for Vogtle, Units 3 and 4.
The ASME OM Code, Subsection ISTC, paragraph ISTC-5260(c), requires at least 20 percent of the charges in explosively actuated valves shall be fired and replaced at least once every 2 years.
Justify requesting an alternative for the second RFO to perform 100-percent testing and replacement of the charges when SNC plans to perform 50-percent testing and replacement during the third and fourth RFOs at Vogtle, Units 3 and 4. Clarify if SNC is not requesting an alternative for those RFOs?
- 4. The specific valves within the scope of this request are as follows:
VALVE NUMBER VALVE NAME RCS-V004A Automatic Depressurization System (ADS) Stage 4 Valves RCS-V004B ADS Stage 4 Valves RCS-V004C ADS Stage 4 Valves RCS-V004D ADS Stage 4 Valves PXS-V118A Containment Recirculation Sumps to Reactor Coolant System (RCS)
Actuation Squib Valves PXS-V118B Containment Recirculation Sumps to RCS Actuation Squib Valves PXS-V120A Containment Recirculation Sumps to RCS Actuation Squib Valves PXS-V120B Containment Recirculation Sumps to RCS Actuation Squib Valves PXS-V123A In-Containment Refueling Water Storage Tank (IRWST) Injection Isolation Valves PXS-V123B IRWST Injection Isolation Valves PXS-V125A IRWST Injection Isolation Valves PXS-V125B IRWST Injection Isolation Valves For each charge in the above valves for Vogtle, Units 3 and 4, What is the date of manufacture?
What is the batch number?
What is the installation date?
What is the date when the service life expires?
- 5. When did the charge manufacturer, Collins Aerospace, notify SNC that it would no longer supply explosive charges to the nuclear industry? Was this notification directly to SNC or a concurrent with industry-wide notice to other AP1000 plant owners/operators? Please specify plant specific SNC notification and any separate industry notices.
- 6. Has SNC contracted with a supplier to manufacture and supply charges for Vogtle, Units 3 and 4? What is the name of the supplier? Is the vendor qualified to supply to the nuclear industry? If not, how long does SNC estimate that it will take for the supplier to be qualified to supply to the nuclear industry? How long does SNC estimate it will take the supplier to manufacture the charges needed for Vogtle, Units 3 and 4? What is SNCs contingency plan if the supplier cannot manufacture charges in time for the second RFO at Vogtle, Unit 3?
Hearing Identifier:
NRR_DRMA Email Number:
2461 Mail Envelope Properties (MN2PR09MB50849525D25DCD9152507207FA072)
Subject:
For Your Action - Request for Additional Information (RAI) - Vogtle, Units 3 and 4
- Alternative Request for Explosively Actuated Valves (L-2023-LLR-0016)
Sent Date:
4/9/2024 2:23:06 PM Received Date:
4/9/2024 2:23:00 PM From:
John Lamb Created By:
John.Lamb@nrc.gov Recipients:
"Joyce, Ryan M." <RMJOYCE@southernco.com>
Tracking Status: None "Lowery, Ken G." <KGLOWERY@southernco.com>
Tracking Status: None Post Office:
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