ML23338A259
| ML23338A259 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 12/08/2023 |
| From: | Dawnmathews Kalathiveettil NRC/NRR/DORL/LPL2-1 |
| To: | Southern Nuclear Operating Co |
| Kalathiveettil D, NRR/DORL/LPL2-1 | |
| Shared Package | |
| ML23338A252 | List: |
| References | |
| EPID L-2022-LLA- 0120 | |
| Download: ML23338A259 (1) | |
Text
December 8, 2023 LICENSEE: Southern Nuclear Operating Company, Inc.
FACILITY: Edwin I. Hatch Nuclear Plant, Units 1 and 2
SUBJECT:
SUMMARY
OF NOVEMBER 28, 2023, OBSERVATION PUBLIC MEETING HELD WITH SOUTHERN NUCLEAR OPERATING COMPANY, INC.,
REGARDING A LICENSE AMENDMENT REQUEST FOR THE REACTOR PRESSURE VESSEL HEAD CLOSURE BOLTS FOR EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2 (EPID NO. L-2022-LLA-0120)
On November 28, 2023, an Observation meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Southern Nuclear Operating Company, Inc. (SNC, the licensee). The purpose of the meeting was to discuss the license amendment request (LAR), dated August 19, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22231B055), as supplemented by letters dated January 20 (ML23020A902) and October 20, 2023 (ML23293A235), to relax the required number of fully tensioned reactor pressure vessel (RPV) head closure bolts in Technical Specification (TS)
Table 1.1-1, MODES, for Edwin I. Hatch Nuclear Plant (Hatch or HNP), Units 1 and 2.
Specifically, this meeting aimed to further discuss and understand SNCs supplement, dated October 20, 2023, that provided responses to the NRCs Request for Additional Information (RAI) dated September 11, 2023 (ML23250A047).
A list of attendees is provided as an Enclosure 1.
On November 11, 2023 (ML23312A160), the meeting was noticed on the NRC public webpage.
The NRC staff opened the meeting with introductory remarks and a roll call of the attendees.
The NRC staff brought up the following discussion topics:
- 1. In its response to RAI-01, SNC stated, in part, that, HNP Unit 1 and Unit 2 TS Sections 3.1 through 3.10 identify the SSCs [structures, systems and components] that are required to be operable. The RPV studs are not an SSC described in Sections 3.1 through 3.10. As such, the TS definition of OPERABLE/OPERABILITY is not applicable to the RPV studs. SNC considers out of service to mean a stud that is not installed or a stud that is or has become less than fully tensioned.
The NRC staff disagreed that the term OPERABLE/OPERABILITY does not apply to the RPV closure bolts. NRC staff explained that TS 3.4.1, Recirculation Loops Operating, provides the limiting condition for operation (LCO) for the reactor coolant system (RCS) recirculation loops and that the RPV is an important component of the RCS that is within the scope of LCO 3.4.1. The RPV bolts are necessary to ensure the integrity of the RPV and, thus, the integrity of the RCS. The NRC staff expressed the view that operability does apply to the RPV bolts.
The NRC staff disagreed with SNCs use of the term out of service and its described meaning and applicability. The NRC understands SNC used the term out of service to mean any closure bolt that is not installed or not fully tensioned. The NRC staff expressed the view that any bolt that is relied upon to meet the TS requirements must meet all the provisions of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. In addition, NRC staff stated that when a closure bolt(s) does not meet the applicable ASME Section XI code inspections, then the licensee must assess whether the non-conforming bolts affect the OPERABILITY of the RPV head as an RCS pressure boundary retaining component. In some cases, evaluation against the Code was done by the licensees contractor and NRC authorization of Code relief. The NRC staff expressed the view that fully tensioning a bolt does not make it operable.
- 2. In its response to RAI-03, SNC did not address the NRCs request to explain how the proposed change does not constitute a material alteration of the facility as originally designed and licensed. NRC staff requested SNC to state whether or not SNC considers the proposed change to be a material alteration of the facility and to provide justification in its revised RAI response.
The NRC staff also questioned if the conditional nature of the proposed TS definition changes and the license condition clarification, warranted consideration of an LCO as required by 10 CFR 50.36(c)(2)(ii), and Criterion 3 in particular, concerning operability of one or more RPV head closure bolts.
- 3. In its response to RAI-04, SNC provided proposed markups to TS Table 1.1-1, and proposed new Hatch Unit 2 renewed facility operating license (RFOL) Condition 2.(C)(3)(j), Reactor Vessel Head Closure Bolts. The proposed license condition would state, Hatch Nuclear Plant Unit 2 is approved to operate in Modes 1 - 4 with at least 55 reactor vessel head closure bolts fully tensioned. If any bolt is less than fully tensioned or out of service, none of the nine adjacent bolts shall have a flaw as a result of the most recent ASME Section XI examination. Upon implementation of Amendment No. , Southern Nuclear Operating Company shall update the Reactor Vessel Reassembly procedure to include this requirement. Additionally, the response also stated, in part, that A license condition is not proposed for Unit 1 because Unit 1 is not operating under an ASME Section XI Code relief for any reactor vessel head closure stud.
NRC staff noted that the use of the term flaw in RFOL condition language needs further clarification with regards to operability. The NRC expressed the view that, if this language is going to be used, it needs to be clearly defined and discussed with respect to operability. The NRC staff expressed the same objection noted in RAI-01 concerning the portion of the license condition that begins with, If any bolt is less than fully tensioned or out of service, in that it lacks clarity with regards to TS operability and
reiterated the applicability to the RPV and RCS. SNCs proposed license condition language does not consider Unit 2 closure bolt #33 to be flawed because SNC plans to fully tension stud #33 as long as they can. With that understanding, the proposed license condition does not ensure that the assumptions in the Dominion contractor analysis are met.
The NRC staff questioned if a license condition should exist for Unit 1 to explain how SNC would respond to a flawed closure bolt in Unit 1. The NRC staff also questioned SNC about following the TS Table 1.1-1 language contained in the cited NRC-approved precedents and using the language All required reactor vessel head closure bolts.
Staff also inquired about tying the use of required to closure bolt operability based on whether its meets applicable Section XI code.
- 4. In its response to RAI-05, SNC stated, in part, that, The only plausible scenario that could result in being unable to properly examine a closure head stud in accordance with IWB-3515.2(c) of the ASME Section XI requirements would be if the stud were stuck in the reactor vessel flange (as in the case currently with Unit 2 stud #33). If a second Unit 2 stud were to be in this condition and removal attempts failed, SNC would ensure the RFOL condition is met and would seek relief from the ASME Section XI examination requirements in accordance with 10 CFR 50.55a(g)(5)(iii).
The NRC staff expressed the view that implementation in this fashion may not preserve the assumptions in the Dominion contractor analysis. The NRC staff expressed concern that if a bolt can be fully tensioned, it is treated as being okay without regard to its ability to meet ASME Section XI. The NRC staff stated that the Dominion contractor analysis and the previously approved Code relief assume that the closure bolt fails (and the RPV remains operable in that condition). Another concern expressed by the NRC was that if a closure bolt is not credited for meeting the TSs (e.g., because it is missing or cannot be tensioned), the bolt is not required to pass the provisions of ASME Section XI. To preserve the assumptions in the Dominion contractor analysis, there must be 9 bolts that are (1) fully tensioned and (2) fully meeting ASME Section XI in between the two bolts that do not meet the above conditions.
Regarding the plan for future Code relief, NRC staff explained that staff cannot pre-judge a future licensing action. The license condition does not relax Code requirements and such relaxation can only be done under 10 CFR 50.55a. If flawed stud #33 is not removed from the flange and instead is still fully tensioned and credited for reactor operation, NRC staff would expect the licensee to complete Section XI Code inspections following the expiration of its current relief authorization on December 31, 2025.
Licensee representatives acknowledged that, even with an approved change in the number of required closure bolts for Mode changes, any installed closure bolts would continue to need to be inspected according to the Code. SNC also stated that to complete ASME inspection of an additional stuck closure bolt in Unit 2, a future relief request would likely be made as opposed to repair/replacement since its contractor analysis would support a second closure bolt that could not be inspected. The NRC staff reiterated the view that such closure bolts would need to be evaluated for their impact on continued RPV and RCS operability, but that ASME Section XI inspection would not be needed if the analysis supports relief.
The NRC staff did not make any regulatory decisions during the meeting. Once a regulatory decision is made, the NRC staff will provide SNC the regulatory decision in writing in a timely manner. Public Meeting Feedback forms were available, but no comments were received.
The meeting adjourned at 12:11 pm Eastern Time (ET).
Please direct any inquiries to me at Dawnmathews.Kalathiveettil@nrc.gov or 301-415-5905.
Sincerely,
/RA/
Dawnmathews T. Kalathiveettil, Project Manager Plant Licensing Branch, II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-321 and 50-366
Enclosures:
List of Attendees cc w/encls: Distribution via Listserv
LIST OF ATTENDEES NOVEMBER 28, 2023, PUBLIC MEETING WITH SOUTHERN NUCLEAR COMPANY REGARDING A REACTOR PRESSURE VESSEL HEAD CLOSURE BOLTS LICENSE AMENDMENT REQUEST EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2 ATTENDEE REPRESENTING Dawnmathews Kalathiveettil U.S. Nuclear Regulatory Commission (NRC)
Jamie Heisserer NRC John Lamb NRC Mike Markley NRC Dave Dijamco NRC Ravi Grover NRC Robert Elliott NRC Kaihwa Hsu NRC Stewart Bailey NRC Kamal Manoly NRC Shivani Mehta NRC Angie Buford NRC Richard Easter NRC Adam Quarles Southern Nuclear Operating Company (SNC)
Ryan Joyce SNC Asif Patel SNC Amy Aughtman SNC Lindsey Grissom SNC Chris Dunham SNC Michael Todd SNC Jimmy Collins SNC Corey Thomas SNC Steve Wideman SNC Enclosure
Package: ML23338A252 Meeting Notice: ML23312A160 Meeting Summary: ML23338A259 NRC-001 OFFICE NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1/LA NRR/DNRL/NVIB/BC NAME DKalathiveettil KGoldstein (ABaxter for) ABuford (JTsao for)
DATE 12/01/2023 12/07/2023 12/04/2023 OFFICE NRR/DSS/STSB/BC NRR/DEX/EMIB/BC NRR/DORL/LPL2-1/BC NAME SMehta SBailey MMarkley DATE 12/06/2023 12/05/2023 12/08/2023 OFFICE NRR/DORL/LPL2-1/PM NAME DKalathiveettil DATE 12/08/2023