ML23248A490

From kanterella
Jump to navigation Jump to search

NCP-2023-004: Non-Concurrence on Round 2 Request for Information on Hatch Reactor Pressure Bolts License Amendment Request
ML23248A490
Person / Time
Site: Hatch  Southern Nuclear icon.png
Issue date: 07/10/2023
From: Markley M
NRC/NRR/DORL/LPL2-1
To: Jamie Heisserer, Dawnmathews Kalathiveettil, Markley M
Division of Operating Reactor Licensing, NRC/NRR/DORL/LPL2-1
Shared Package
ML24114A070 List:
References
NCP-2023-004
Download: ML23248A490 (1)
v • d • e


Text

NRC FORM 757 U.S. NUCLEAR REGULATORY COMMISSION (06-2019)

NRC MD 10.158 NON-CONCURRENCE PROCESS COVER PAGE

The U.S. Nuclear Regulatory Commission (NRC) strives to establish and maintain an environment that encourages all employees to promptly raise concerns and differing views without fear of reprisal and to promote methods for raising concerns that will enhance a strong safety culture and support the agencys mission.

Employees are expected to discuss their views and concerns with their immediate supervisors on a regular, ongoing basis. If informal discussions do not resolve concerns, employees have various mechanisms for expressing and having their concerns and differing views heard and considered by management.

Management Directive (MD) 10.158, NRC Non-Concurrence Process, describes the Non-Concurrence Process (NCP).

The NCP allows employees to document their differing views and concerns early in the decision-making process, have them responded to (if requested), and include them with proposed documents moving through the management approval chain to support the decision-making process.

NRC Form 757, Non-Concurrence Process, is used to document the process.

Section A of the form includes the personal opinions, views, and concerns of a non-concurring NRC employee.

Section B of the form includes the personal opinions and views of the non-concurring employees immediate supervisor.

Section C of the form includes the agencys evaluation of the concerns and the agencys final position and outcome.

NOTE: Content in Sections A and B reflects personal opinions and views and does not represent the official agencys position of the issues, nor official rationale for the agency decision. Section C includes the agencys official position on the facts, issues, and rationale for the final decision.

1. Was this process discontinued? If so, please indicate the reason and skip questions 2 and 3:

Process was not discontinued

2. At the completion of the process, the non-concurring employee(s):

Continued to non-concur

3. For record keeping purposes:

This record has been reviewed and approved for public dissemination

NRC FORM 757 (06-2019) Page 1 of 8 Use ADAMS Template NRC-006 (ML063120159)

NRC FORM 757 U.S. NUCLEAR REGULATORY COMMISSION 1. NCP Tracking Number (06-2019) NCP-2023-004 NRC MD 10.158 Date NON-CONCURRENCE PROCESS (Continued) 2023-07-10

Section A - To Be Completed by Non -Concurring Employee

2. Title of Subject Document 3. ADAMS Accession Number Round 2 RAIs - Hatch RPV Bolts LAR ML23250A047
4. Document Signer 5. Document Signers Office 6. Document Signers Email Jamie Heisserer (She/Her/Hers) - DEP DIR, NRR Jamie.Heisserer@nrc.gov DIV OF OPER REAC LIC
7. Name of Non-Concurring Employees 8. Non-Concurring Employee Offices 9. Employee Emails Michael Markley - BRANCH CHIEF NRR Michael.Markley@nrc.gov
10. Non-Concurring Employees Role for the Subject Document On Concurrence
11. Name of Non-Concurring Employee Supervisors 12. Non-Concurring Employee Supervisor Offices13. Supervisor Emails Jamie Heisserer (She/Her/Hers) - DEP DIR, NRR Jamie.Heisserer@nrc.gov DIV OF OPER REAC LIC 14.

I would like my non-concurrence considered and would like a written evaluation in Sections B and C.

15. When the process is complete, I would like management to determine whether public release of the NCP Form (with or without redactions) is appropriate (Select No if you would like the NCP Form to be non-public):

Yes

16. Reasons for the Non-Concurrence, Potential Impact on Mission, and the Proposed Alternatives This non-concurrence is on management's rejection of 2nd round RAIs (request for additional information) Nos. RAI-04 and RAI-05 (yellow highlight) in the attached list of six RAIs that are related to Southern Nuclear Operating Company's proposed amendme nt request dated August 19, 2022, (Agencywide Documents Access and Man agement System (ADAMS) Accession No. ML22231B055), as supplemented by letter dated January 20, 2023 (ML23020A902), that would revise technical specifications (TSs) for Edwin I. Ha tch, Units 1 and 2, to relax required number of fully tensioned reactor pressure vessel head (RPV) closure bolts in TSs Table 1.1-1, MODES. While the RAIs are not in a formal concurrence memorandum, as RAIs are often dispatched by e -mail and then docketed, NRR Office Instructions LIC-101 and LIC-115, place approval at the "division" level. By e-mail dated dated June 30, 2023 (attached), DORL management accepts RAI -01, RAI-02, RAI-03, and RAI-06, but rejects RAI-04 and RAI-05. Informal discussions about defense-in-depth and protecting the barriers to the release of radiation concerning these amendments has been ongoing since early February 2023. Proposed RAI-04 is derived primarily from the principles and guidance in Regulatory Guide 1.174.

Proposed RAI-05 is based on longstanding RPV closure bolt maintenance challenges at Hatch (since 2017) in repair/replacement of RPV closure bolts in Hatch Unit 2. The Summary of Issues for this non-concurrence is attached.

17. Submitted By / Submitted On 2023-07-10 Michael Markley - BRANCH CHIEF

NRC FORM 757 (06-2019) Page 2 of 8 Use ADAMS Template NRC-006 (ML063120159)

NRC FORM 757 U.S. NUCLEAR REGULATORY COMMISSION 1. NCP Tracking Number (06-2019) NCP-2023-004 NRC MD 10.158 Date NON-CONCURRENCE PROCESS (Continued) 2023-07-19

Section B - To Be Completed by Non-Concurring Employees Supervisor

2. Title of Subject Document 3. ADAMS Accession Number Round 2 RAIs - Hatch RPV Bolts LAR ML23250A047
4. Name of Non-Concurring Employees Supervisor 5. Non-Concurring Employees Supervisor Email6. Office Jamie Heisserer (She/Her/Hers) - DEP DIR, DIV Jamie.Heisserer@nrc.gov NRR OF OPER REAC LIC
7. Comments for the NCP Reviewer to Consider I am grateful for the submitters raising of differing views in the licensing process. As a result of raising differing views at the time the original safety evaluation was drafted, staff held two public meetings with the licensee and drafted a second round of requests for additional information (RAIs) that will be necessary for the NRC to have the clarity and information necessary to reach a safety conclusion on the license amendment request (LAR). As an agency, we will get to a better place because of the submitters views, and I am extremely appreciative of that. As noted in my email dated June 30, 2023, attached to the submitters Section A of this nonconcurrence, I support moving forward with four of the six proposed RAIs. I would like to amend part of that decision and state that I also support requesting a portion of proposed RAI 4 as edited below: During the NRCs May 2, 2023, public meeting (Meeting Summary - ML23136B294), SNC proposed a revision to Unit 2 TS Table 1.1 -1 footnotes along with a proposed Unit 2 license condition. Please provide any updated proposed revisions to TS Table 1.1 -1 along with SNCs proposed license condition(s) for each unit. For the remainder of proposed RAI 4 and RAI 5, I discussed part of the reasoning for deciding against their inclusion in the second round RAIs in the June 30 email. Since June 5, three meetings have been held for managemen t to understand the proposed second round of RAIs. In the June 5 meeting, the need for the information to make a safety determination on the LAR for the four approved RAIs was made clear by DORL and the technical staff and management, and those questions are supported. Two additional meetings were held on June 13 and 22 to discuss the need for proposed RAIs 4 and 5 in more depth. For both quest ions, they are broad in nature and not clear on what information is missing in the application to make a safety determination. The applicable technical branches indicated that the questions were not needed to make a safety determination. These questions d o not appear to meet the intent of LIC-115, Processing Requests for Additional Information. For example, RAI 4 asks, in part, how a defense-in-depth philosophy in a regulatory guide, is being met. This is a broad question that does not make clear what information is missing from the application. It also asks to justify the continuing need for the amendment based on the completion of the Unit 2 refueling outage, which we do not have a regulatory basis to ask the licensee. Licensees have the right to ask for changes to the design basis of their plant and the licensee would have withdrawn the LAR had they wanted to do so. RAI 5 relates to the licensees implementation of the maintenance rule. The LAR does not change or imply changes to the maintenance rule or aging management programs, so there is not a clear basis to ask the RAI for this application. The RAI indicates that there is a need to justify the basis for a permanent TS change in lieu of additional time to inspect and repair/replace closure bolts. Again, licensees have the right to ask for changes to the design and licensing basis of their plant. The NRC has approved permanent changes with respect to the number of required vessel head closure bolts as early as 1999 with the Callaway TS approval. If there are concerns related to implementation of a program, which this question implies and was stated during the meeting to discuss this RAI, they would be best addressed through the inspection and assessment process led by resident inspectors and the regional office. Again, I am grateful to the submitter for raising concerns, which resulted in additional engagement between DORL, the technical divisions and the licensee.

I believe that the four approved second round RAIs will yield the information the NRC needs to make a safety conclusion on the acceptability of this LAR.

8. Reviewed By / Reviewed On 2023-07-19 Jamie Heisserer (She/Her/Hers) - DEP DIR, DIV OF OPER REAC LIC

NRC FORM 757 (06-2019) Page 3 of 8 Use ADAMS Template NRC-006 (ML063120159)

NRC FORM 757 (06-2019) Page 4 of 8 Use ADAMS Template NRC-006 (ML063120159)

NRC FORM 757 U.S. NUCLEAR REGULATORY COMMISSION 1. NCP Tracking Number (06-2019) NCP-2023-004 NRC MD 10.158 Date NON-CONCURRENCE PROCESS (Continued) 2023-08-31

Section C - To Be Completed by NCP Coordinator

2. Title of Subject Document 3. ADAMS Accession Number Round 2 RAIs - Hatch RPV Bolts LAR ML23250A047
4. Name of NCP Coordinator 5. NCP Coordinators Email 6. Office David Wrona - BRANCH CHIEF David.Wrona@nrc.gov NRR
7. Agreed Upon Summary of Issues The non-concurrence is on managements rejection of two second round requests for additional information (RAIs) numbered RAI -04 and RAI-05 attached to the non -concurrence. Below is a summary of the issues. RAI-04 ISSUE 1: Proposed RAI -04 is consistent with NRC policy and procedures.
  • The Commissions Final Policy Statement (60 FR 42622; August 16, 1995) on the,Use of Probabi listic Risk Assessment Methods in Nuclear Regulatory Activities, supports the use of PRA methods and data and in a manner that complements the NRCs deterministic approach.
  • SRM on SECY 144, White Paper on Risk -informed and Performance -based Regulation, supports the risk-informed approach and defense -in-depth and states, in part, that the concept of defense-in depth is a fundamental tenet of regulatory practice in the nuclear field and risk insights can make the elements of defense in depth more clear.
  • NRR Office Instruction LIC-206, Integrated Risk-informed Decision-making for Licensing Reviews, provides a basic framework for NRC staff in considering risk insights and other licensing-related activities in its reviews, even when the submittal contains no PRA information and little or no risk discussion. ISSUE 2: Proposed RAI-04 is consistent with RG 1.174 consideration of defense-in-depth.
  • Regulatory Guide 1.174, Revision 3, An Approach for Using Probabilistic Risk Assessment in Risk-informed Decisions on Plant-Specific Changes to the Licensing Basis, provides the latest NRC regulatory position and standard for consideration of defense-in-depth in licensing and regulatory activities.
  • Section 2.1.1.2, Considerations for Evaluating the Impact of the Proposed Licensing Basis Change on Defense in Depth, in RG 1.174, provides seven considerations that should be used to evaluate the impact of the change on defense-in-depth.
  • The Hatch amendment analysis is limited primarily to applicability of the 7th consideration Section 2.1.1.2 in RG 1.174, of continuing to meet the analyzed plant design criteria for tensioning but is insufficient in addressing the other considerations including: containing the source term, managing temporary conditions to limit exposure to risk, preserving adequate defense against common-cause failures (CCF), maintaining the fission product barrier, and defense against human errors (Considerations 1, 3, 4, 5, and 6, respectively). ISSUE 3: Proposed RAI-04 is consistent with the principles in RG 1.174.
  • RG 1.174 states, in part, that, All safety impacts of the proposed licensing basis changes are evaluated in an integrated manner. The evaluation is part of an overall risk management approach in which the licensee is using risk analysis to improve operational and engineering decisions broadly by identifying and taking advantage of opportunities to reduce risk and not just to eliminate requirements the licensee sees as undesirable. The Hatch submittal is entirely a paper-fix to reduce requirements and represents an unquantified reduction in safety margin.
  • RG 1.174 states, in part, that The proposed licensing basis change should not significantly reduce defenses against CCFs that could defeat the redundancy, independence, or diversity of the layers of defense; fission product barriers; and the design, operational, or maintenance aspects of the plant. The Hatch submittal does not evaluate the potential to introduce a CCF of the RPV head O -rings during operational events including seismic. Prompt failure of the O-rings would be a small-break loss-of-coolant accident.
  • The Hatch submittal proposes to reduce necessary conservatism in the original design and licensing basis and is inconsistent with the PRA Policy Statement and RG 1.174 with regard to the use of risk insights to reduce unnecessary conservatism and unnecessary burden. ISSUE 4: While compliance with the ASME Code is important for inspection and for conducting repair/replacement, it is not the only criteria for approving an amendment.
  • The Environmental considerations must be able to conclude no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. As noted in RAI-03, an outstanding regulatory question remains whether the licensees assertion please discuss whether the assertion in its no significant hazards consideration that no hardware changes are proposed accurately reflects the proposed change, which, if approved, would allow operation with up to two RPV head closure bolts not installed or torqued. Based on the licensees subm ittal

NRC FORM 757 (06-2019) Page 5 of 8 Use ADAMS Template NRC-006 (ML063120159) dated August 19, 2022, the NRC issued a no significant hazards consideration in the Federal Register on November 1, 2022, (87 FR 65834).

  • The amendments must be able to conclude that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public. With uneven RPV head tensioning and the potential for single failure of additional closure bolts, there is an increased vulnerability of prompt RPV head O-rings failure and a small-break loss-of-coolant accident. As such, the integrity of the reactor coolant pressure boundary as a fission product barrier is questionable in the proposed amendments. ISSUE 5: NRC should not predetermine how a licensee may respond to an RAI or prejudge that a licensee cannot satisfy an RAI as a basis not asking it.
  • Licensee should be able to respond to any NRC amendment-related question about defense-in-depth, regardless of whether a submittal is entirely deterministic, uses risk insights, or is submitted as a risk-informed submittal in accordance with RG 1.174.
  • From a safety culture perspective, it is troubling that the NRC does not see a regulatory basis for asking RAI-04 and weve predetermined they wouldnt be able to satisfy.
  • NRR is organized in a matrix/project management structure where diverse technical, risk, and licensing expertise support an integrated decision-making process. Office Instruction LIC-101 and LIC-206 support the integrated decision-making process for amendments. Each NRR group or branch has an opportunity to ask RAIs for its portion of the review. However, the DORL project manager and DORL branch chief have unique roles in that they that sign the amendment letter and license, respectively, and in some cases, the DORL PM drafts the final safety evaluation for concurrence-only approval by the technical branches. While the technical branches have input, the decision-making authority for issuance of amendments remains with DORL at the branch level with some exceptions (e.g., power uprates). The same is true for RAIs. DORL has as much legitimate authority to ask RAIs as any technical branch. RAI-05 ISSUE 1: RAI-05 is consistent with the requirements of 10 CFR 50.65
  • Section (a)(1) of 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants, states, in part, that Each holder of an operating license for a nuclear power plant under this part and each holder of a combined license under part 52 of this chapter after the Commission makes the finding under § 52.103(g) of this chapter, shall monitor the performance or condition of structures, systems, or components, against licensee-established goals, in a manner sufficient to provide reasonable assurance that these structures, systems, and components, as defined in paragraph (b) of this section, are capable of fulfilling their intended functions.
  • Section (b)(1) of 10 CFR 50.65 states, in part, that Safety-related structures, systems and components that are relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe shutdown condition, or the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposure comparable to the guidelines in Sec.

50.34(a)(1), Sec. 50.67(b)(2), or Sec. 100.11 of this chapter, as applicable.

  • The proposed amendments for the RPV head closure bolts are the result of failed maintenance to correct Unit 2 RPV head closure bolt #33. The licensees strategy, as provided in the LAR, is to discontinue monitoring the condition of closure bolt #33 and any new emergent single closure bolt issues for the life of the plant.

Despite regulatory relief in 2017 and 2019, the licensee has failed to develop and execute a plan for corrective action. Instead, the licensee intends to exclude closure bolt #33 and an additional bolt in Unit 2 and a single closure bolt in Unit 1, for which no defects are known presently, from the TS and condition monitoring. If the licensee is excluding equipment as important as the RPV head closure bolts, NRC should be concerned about other yet unknown SSCs that are not receiving the expected maintenance and condition monitoring. ISSUE 2: RAI-05 is consistent with the 10 CFR 54.37(b) and RIS 2007-16, Revision 1

  • Section (b) of 10 CFR 50.37, Additional records and recordkeeping requirements, states that After the renewed license is issued, the FSAR update required by 10 CFR 50.71(e) must include any systems, structures, and components newly ident ified that would have been subject to an aging management review or evaluation of time -limited aging analyses in accordance with § 54.21. This FSAR update must describe how the effects of aging will be managed such that the intended function(s) in § 54.4(b) will be effectively maintained during the period of extended operation.
  • RIS 2007-016, Revision 1, Implementation of the Requirements of 10 CFR 50.37(b) for Holders if Renewed Licenses, states in part, that The FSAR update required by 10 CFR 54.37(b ) must include newly identified SSCs that would have been subject to an aging management review or evaluation as a TLAA in accordance with 10 CFR 54.21. The FSAR update need s to describe how the licensee will manage the effects of aging in order to effectively maintain the intended function(s) in 10 CFR 54.4(b) during the period of extended operation.
  • RAI-05 is applicable to the licensees aging management review and time -limited aging analyses (TLAAs) program and for reporting on newly identified structures, systems, and components (SSCs) that would have been subject to aging management review or as a TLAA in accordance with 10 CFR 54.21. It is not apparent how the licensee is

NRC FORM 757 (06-2019) Page 6 of 8 Use ADAMS Template NRC-006 (ML063120159)

treating or reporting on degraded or inoperable RPV head closure bolts in accordance with 10 CFR 54.

  • The Hatch accident analysis presumes a fully tensioned RPV head in the original design and license. The licensees analysis appears to be overly optimistic in presuming specific safe locations of further degradation rather analyzing for the most limiting locations that could adversely affect the RPV head O-rings and fission product barrier integrity over the life of the plant.
  • Revision 39 to Updated Safety Analysis Report, Chapters 8 through 18, Appendix A (ML23135A071), Section 18.2.12, Component Cyclic or Transient Limit Program, states, in part, that The four limiting high stress RPV boundary components are the RPV main closure studs, the RPV shell, the RPV recirculation inlet nozzles, and the RPV feedwater nozzles. As such, the RPV head closure bolts are among the highest stress-limiting SSCs in the plant.
  • Page 3-36 of NUREG-1803, [2:3] Section 3 Section 3-212, Safety Evaluation Report Related to the License Renewal of the Edwin I. Hatch Nuclear Plant Units 1 and 2 (ML020020291), the NRC safety evaluation states, in part, that Bolting that is heat treated to a high hardness condition and exposed to a humid environment within containment could be susceptible to SCC [stress corros ion cracking]. In response to RAI 3.4-1, the applicant did not state if the yield strength for ASME SA-1 93 (Grade B7) or any other bolts are limited to less than 150 ksi to avoid the possibility of stress corrosion cracking. (See RICSIL No. 055, February 1, 1991, "RPV Head Stud Cracking."). In Open Item 3.1.11-1, the staff requested that the applicant provide this information. By letter dated June 5, 2001, the applicant stated that these bolts were procured with a minimum yield strength of 105 ksi, with no upper limit stated. How ever, the applicant also stated that it has not experienced problems with these bolts and could not identify any problems during a survey of industry experience. On the basis that the applicant's operating experience has not shown that these bolts have experience d SCC, the staff finds the applicant's response adequate and considers Open Item 3.1.11 -1 closed. Clearly, the situation has changed with regard to the condition of the Hatch Unit 2 RPV head closure bolts, and licensee aging management and reporting of these SSCs warrants further evaluation.
8. Evaluation of Non-Concurrence and Rationale for Decision I appreciate the non-concurring staff members thoughtful views on the request for additional information (RAI) and his use of the non-concurrence process to raise concerns. I also appreciate the comments provided by the non-concurring employees supervisor in Section B and find them to be consistent with my evaluation discussed below. I concur with the recommendation and revision proposed by the supervisor to RAI 4 as stated Section B. The issue identified in the non-concurrence is related to non-agreement by division management, per LIC-115, to the issuance of two (i.e., RAI 4 and RAI 5) second round RAIs on the Southern Nuclear Operating Company's proposed amendment request to relax required number of fully tensioned reactor pressure vessel head (RPV) closure bolts in TSs Table 1.1-1, MODES. The non-concurring staff raised several issues related to Regulatory Guide 1.174 (RAI 4) and 10 CFR 50.65 (RAI 5) as his basis for needing these RAIs. It is the NRCs policy, as described in LIC-115, for staff to issue RAIs, when necessary, to support reasonable assurance findings in accordance with the NRC rules and regulations. The information requested typically addresses missing, incomplete, inconsistent, or unclear information within the application or other docketed correspondence. RAIs should include concise statements of information needed to complete the technical review, indicate the significance of the issue, and possess a clear and understandable regulatory basis. RAIs should also be as direct as possible and avoid being open-ended. Regarding the non-concurring staffs issues related to RAI 4, I understand and agree that the NRC's policy and guidance on the use of probabilistic risk assessment (PRA) provide the framework for using risk insights as they are available.

However, I dont see evidence of how citing the various guidance from RG 1.174 supports the case for why the information requ ested in RAI-04 is necessary to fill any holes in the draft safety evaluation. For example, if the application is insufficient in addressing defense in depth (DID), the RAI needs to clearly state what that insufficiency is and what is needed to meet the standard; broadly asking an RAI for a response on how DID is met presents the risk of it being open -ended and not getting to the heart of the technical/safety concern, thus, extending the review process unnecessarily. Further, nothing in RG 1.174 precludes or prohibi ts a licensee from submitting and defending its basis for reduction in safety margin, so the staff should provide and defend any necessary conservatism it deems appropriate with clearly defined and applicable thresholds or standards. In addition, my objection to asking RAI-04 is not based on predetermination by how the licensee may respond. Rather, it is based on my read that RAI -04 is philosophical in nature and does not clearly articulate the specific technical/safety concerns with the licensee's current application.

Finally, while I agree that DORL has a legitimate role equal to the technical branches in the RAI process, we should still adhere to the principle that each RAI should be firmly supported with a regulatory and technical basis. Regarding the non -concurring staffs issues related to RAI 5, it implies that there are NRC concerns regarding the implementation of aging management programs at the sit e.

However, there is no basis provided to support this claim through specific documented findings from the NRCs oversight process. In

NRC FORM 757 (06-2019) Page 7 of 8 Use ADAMS Template NRC-006 (ML063120159)

addition, as written, RAI 5 also implies that the Maintenance Rule under 10 CFR 50.65 would not allow for the licensee to request a permanent change in TS for the RPV stud, to which there is no supporting regulatory basis. In conclusion, I do not approve of the issuance of RAI 4 and RAI 5 as proposed in Section A Attachment - NCP-2023-004 - Round-2 RAIs - Rev 4 - Hatch RPV Bolts LAR (002).docx. I approve a portion of proposed RAI 4 to be issued as follows: During the NRCs May 2, 2023, public meeting (Meeting Summary - ML23136B294), SNC proposed a revision to Unit 2 TS Table 1.1 -1 footnotes along with a proposed Unit 2 license condition. Please provide any updated proposed revisions to TS Table 1.1 -1 along with SNCs proposed li cense condition(s) for each unit. I thank the non-concurring staff for his questioning attitude and expressing it through the NCP process.

9. Coordinated By / Coordinated On 2023-08-31 David Wrona
10. Approved By / Approved On 2023-08-31 Bo Pham - DIR DIV OF OPERATING REACTOR LIC

NRC FORM 757 (06-2019) Page 8 of 8 Use ADAMS Template NRC-006 (ML063120159)

Round 2 RAIs - Hatch RPV Bolts LAR

RAI-01

The Hatch submittal uses the term out of service extensively in describing the proposed technical specification TS changes for RPV bolts.

1) Please provide an explanation of SNCs proposed use of out of service in the TS as compared to the current TS OPERABLE/OPERABILITY definition.
2) If a bolt is less than fully tensioned, is it considered OPERABLE, and if so, please justify?

RAI-02

In the January 20, 2023, RAI response submittal (ML23020A902), the licensee states that it fully intends to employ sound engineering principles to maintain all RPV bolts in service. If a flaw is found during a Section XI inspection in an RPV bolt that will not be repaired or replaced, what are the licensees requirements to determine the maximum allowable torque that will be applied during tensioning of that bolt prior to plant startup?

RAI-03

If approved, the latest proposed TS changes (Meeting Summary - ML23136B294) would allow one bolt from each unit to either not be installed or installed and not fully torqued. Please explain how this does not constitute a material alteration of the facility as originally designed and licensed. Based on the above, please discuss whether the assertion in the No Significant Hazards Consideration that no hardware changes are proposed accurately reflects the proposed change, which would allow operation with up to two RPV head closure bolts not installed or torqued.

RAI-04

During the NRCs May 2, 2023, public meeting (Meeting Summary - ML23136B294), SNC proposed a revision to Unit 2 TS Table 1.1-1 footnotes along with a proposed Unit 2 license condition.

Although not a risk-informed submittal, the NRC has concerns regarding how the proposed change would meet certain principles of risk-informed decision making. The NRC recognizes and allows temporary configurations within established programs when they provide adequate safety and are needed for operation. However, the proposed changes, if approved, would allow any one bolt in each unit to be left less than fully tensioned, potentially for the life of the plant.

1) How would the proposed change be consistent with the defense-in-depth philosophy described in Regulatory Guide 1.174, Revision 3?
2) How will SNC ensure that any impact of the proposed licensing basis change on defense-in-depth is fully understood and addressed?
3) Please describe expected containment of the source term if a severe accident occurs, without an overreliance on programmatic activities as compensatory measures.
4) Based on the completion of the Unit 2 refueling outage, please justify the continuing need for the proposed amendments.
5) Please provide any updated proposed revisions to TS Table 1.1-1 along with SNCs proposed license condition(s) for each unit.

RAI-05

Please describe how the Hatch maintenance rule implementation and aging management programs capture the Hatch vessel head closure bolts and justify the basis for a permanent TS change in lieu of additional time to inspect and repair/replace closure bolts.

RAI-06

During the NRCs May 2, 2023, public meeting (Meeting Summary - ML23136B294), SNC proposed a revision to Unit 2 TS Table 1.1-1 footnotes along with a proposed Unit 2 license condition.

Please discuss licensee actions that would be taken if more than one reactor head closure bolt cannot be properly examined in accordance with Table IWB-2500- 1 of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI.

Verizon.com/nurses Get started. ID.me verification. Off to nurses landing page. Click the link to return back to enrollment. Select already with Verizon. Log in with my Verizon credentials.

Discount should be 20 off monthly bill.

From: Jamie Heisserer (She/Her/Hers)

To: Dawnmathews Kalathiveettil; Michael Markley Cc: Bo Pham

Subject:

Hatch Round-2 RAIs Date: Friday, June 30, 2023 12:46:44 PM

Good afternoon Dawnmathews and Mike,

How are you? Thanks for your patience as we work through alignment on the second round of RAIs for Hatch. This is a complex application and I appreciate your communication on this. Based on the meetings held on June 13 and June 22, DORL supports the issuance of proposed RAIs 1, 2, 3 and 6.

Bo and I very sincerely appreciate the professionalism and safety focus in raising differing views associated with this LAR. I am very grateful that the concerns were raised as they yielded additional discussions in public meetings with the licensee and further evaluation by the staff. The answers SNC will provide to proposed questions 1, 2, 3 and 6 are going to be critical to the NRC making a safety determination on this request and we would not have realized that this information was needed without the raising of differing views. Thank you both!

As weve had several conversations about this, Id like to provide you our basis for not approving proposed RAIs 4 and 5.

For question 4, during the meeting on June 22, the RAI was discussed extensively with the other divisions, mainly with DRA and DEX, to align on the need and appropriateness of the RAI. While there wasnt opposition to asking a question about defense-in-depth/safety margin or referencing RG 1.174, the general consensus from the technical divisions was that we would expect the licensee to respond that theyve met DID requirements by meeting the ASME requirements with margin, which seems to obviate the need for such an ask. The technical staff leading the review of the LAR further expressed that they did not have a need for an RAI on DID to make a safety determination on this amendment. We acknowledge that you may see the need for the question to prevent the licensee from being able to ask for such a permanent change to their licensing basis. However, we dont have a supportable regulatory basis to ask an RAI for that purpose nor should we ask for something that weve predetermined they wouldnt be able to satisfy.

For question 5, during the meeting on June 13, again we discussed the RAI extensively between DORL, DEX, DNRL and DSS staff and management. In that meeting, none of the technical division management or staff supported the issuance of the RAI. The LAR does not change or imply changes to the maintenance rule or aging management programs, so there is not a regulatory basis for the question.

Thank you again so much for bringing your views to the forefront. Even though we dont support all 6 proposed RAIs, we truly feel that the 4 that we are moving forward with are going to get us to a much better place from a safety perspective. We fully support the exercising of any process youd choose to follow if you disagree with this decision.

Thank you!

Jamie From: Dawnmathews Kalathiveettil <Dawnmathews.Kalathiveettil@nrc.gov>

Sent: Tuesday, June 20, 2023 10:24 AM To: Jamie Heisserer (She/Her/Hers) <Jamie.Heisserer@nrc.gov>

Cc: Michael Markley <Michael.Markley@nrc.gov>

Subject:

Touching base regarding Hatch Round-2 RAIs Importance: High

Good morning Jamie,

I wanted to touch base regarding Hatchs Round-2 RAIs. Based on the discussions last Tuesday, the DDs believed that RAI #5 (maintenance rule and aging management) was irrelevant and can be removed. Similarly, we touched upon RAI #4 very briefly and seemed the consensus was that SNC was most probably going to respond stating that they still have adequate/sufficient defense-in-depth (D3) since their calculations show that and there is still adequate/sufficient margin as they meet the ASME allowables for the RPV Head.

Do you plan to hold another DD meeting to further discuss RAI #4? Or will you be sending us the final approved list of RAIs this week?

Once I get the approved list, I will need to provide SNC the draft RAIs and set up a clarification call (SNC will possibly request) before officially sending it out (beginning of July). As of right now, the project completion is scheduled for September 11, 2023.

Best Regards,

Dawnmathews T. Kalathiveettil Hatch Project Manager Plant Licensing Branch (LPL 2-1)

DORL - O8 C02 Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission

Office Phone: 301-415-5905 Email: Dawnmathews.Kalathiveettil@nrc.gov

Michael T. Markley July 10, 2023

NON-CONCURRENCE ROUND 2 RAIs FOR EDWIN I. HATCH REACTOR PRESSURE VESSEL (RPV)

HEAD CLOSURE BOLT AMENDMENTS (EPID L-2022-LLA-0120)

SUMMARY

OF ISSUES

RAI-04

ISSUE 1: Proposed RAI-04 is consistent with NRC policy and procedures.

  • The Commissions Final Policy Statement (60 FR 42622; August 16, 1995) on the, Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities, supports the use of PRA methods and data and in a manner that complements the NRCs deterministic approach.
  • SRM on SECY-98-144, White Paper on Risk -informed and Performance-based Regulation, supports the risk-informed approach and defense-in-depth and states, in part, that the concept of defense-in depth is a fundamental tenet of regulatory practice in the nuclear field and risk insights can make the elements of defense in depth more clear.
  • NRR Office Instruction LIC-206, Integrated Risk -informed Decision-making for Licensing Reviews, provides a basic framework for NRC staff in considering risk insights and other licensing-related activities in its reviews, even when the submittal contains no PRA information and little or no risk discussion.

ISSUE 2: Proposed RAI-04 is consistent with RG 1.174 consideration of defense-in-depth.

  • Regulatory Guide 1.174, Revision 3, An Approach for Using Probabilistic Risk Assessment in Risk-informed Decisions on Plant-Specific Changes to the L icensing Basis, provides the latest NRC regulatory position and standard for consideration of defense-in-depth in licensing and regulatory activities.
  • Section 2.1.1.2, Considerations for Evaluating the Impact of the Proposed Licensing Basis Change on Defense in Depth, in RG 1.174, provides seven considerations that should be used to evaluate the impact of the change on defense-in-depth.
  • The Hatch amendment analysis is limited primarily to applicability of the 7th consideration Section 2.1.1.2 in RG 1.174, of continuing to meet the analyzed plant design criteria for tensioning but is insufficient in addressing the other considerations including: containing the source term, managing temporary conditions to limit exposure to risk, preserving adequate defense against common-cause failures (CCF), maintaining the fission product barrier, and defense against human errors (Considerations 1, 3, 4, 5, and 6, respectively).

ISSUE 3: Proposed RAI-04 is consistent with the principles in RG 1.174.

  • RG 1.174 states, in part, that, All safety impacts of the proposed licensing basis changes are evaluated in an integrated manner. The evaluation is part of an overall risk management approach in which the licensee is using risk analysis to improve operational and engineering decisions broadly by identifying and taking advantage of opportunities to reduce risk and not just to eliminate requirements the licensee sees as

1 Michael T. Markley July 10, 2023

undesirable. The Hatch submittal is entirely a paper -fix to reduce requirements and represents an unquantified reduction in safety margin.

  • RG 1.174 states, in part, that The proposed licensing basis change should not significantly reduce defenses against CCFs that could defeat the redundancy, independence, or diversity of the layers of defense; fission product barriers; and the design, operational, or maintenance aspects of the plant. The Hatch submittal does not evaluate the potential to introduce a CCF of the RPV head O -rings during operational events including seismic. Prompt f ailure of the O-rings would be a small -break loss-of-coolant accident.
  • The Hatch submittal proposes to reduce necessary conservatism in the original design and licensing basis and is inconsistent with the PRA Policy Statement and RG 1.174 with regard to the use of risk insights to reduce unnecessary conservatism and unnecessary burden.

ISSUE 4: While compliance with the ASME Code is important for inspection and for conducting repair/replacement, it is not the only criteria for approving an amendment.

  • The Environmental considerations must be able to conclude no significant increase in the amounts and no significant change in the types of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure. As noted in RAI-03, an outstanding regulatory question remains whether the licensees assertion please discuss whether the assertion in its no significant hazards consideration that no hardware changes are proposed accurately reflects the proposed change, which, if approved, would allow operation with up to two RPV head closure bolts not installed or torqued. Based on the licensees submittal dated August 19, 2022, the NRC issued a no significant hazards consideration in the Federal Register on November 1, 2022, (87 FR 65834).
  • The amendments must be able to conclude that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public. With uneven RPV head tensioning and the potential for single failure of additional closure bolts, there is an increased vulnerability of prompt RPV head O-rings failure and a small-break loss-of-coolant accident. As such, the integrity of the reactor coolant pressure boundary as a fission product barrier is questionable in the proposed amendments.

ISSUE 5: NRC should not predetermine how a licensee may respond to an RAI or prejudge that a licensee cannot satisfy an RAI as a basis not asking it.

  • Licensee should be able to respond to any NRC amendment -related question about defense-in-depth, regardless of whether a submittal is entirely deterministic, us es risk insights, or is submitted as a risk -informed submittal in accordance with RG 1.174.
  • From a safety culture perspective, it is troubling that the NRC does not see a regulatory basis for asking RAI-04 and weve predetermined they wouldnt be able to satisfy.
  • NRR is organized in a matrix/project management structure where diverse technical, risk, and licensing expertise support an integrated decision-making process. Office Instruction LIC-101 and LIC-206 support the integrated decision-making process for

2 Michael T. Markley July 10, 2023

amendments. Each NRR group or branch has an opportunity to ask RAIs for its portion of the review. However, the DORL project manager and DORL branch chief have unique roles in that they that sign the amendment letter and license, respectively, and in some cases, the DORL PM drafts the final safety evaluation for concurrence-only approval by the technical branches. While the technical branches have input, the decision-making authority for issuance of a mendments remains with DORL at the branch level with some exceptions (e.g., power uprates). The same is true for RAIs. DORL has as much legitimate authority to ask RAIs as any technical branch.

RAI-05

ISSUE 1: RAI-05 is consistent with the requirements of 10 CFR 50.65

  • Section (a)(1) of 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants, states, in part, that Each holder of an operating license for a nuclear power plant under this part and each holder of a combined license under part 52 of this chapter after the Commission makes the finding under § 52.103(g) of this chapter, shall monitor the performance or condition of structures, systems, or components, against licensee-established goals, in a manner sufficient to provide reasonable assurance that these structures, systems, and components, as defined in paragraph (b) of this section, are capable of fulfilling their intended functions.
  • Section (b)(1) of 10 CFR 50.65 states, in part, that Safety -related structures, systems and components that are relied upon to remain functional during and following design basis events to ensure the integrity of the reactor coolant pressure boundary, the capability to shut down the reactor and maintain it in a safe shutdown condition, or the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposure comparable to the guidelines in Sec. 50.34(a)(1), Sec.

50.67(b)(2), or Sec. 100.11 of this chapter, as applicable.

  • The proposed amendments for the RPV head closure bolts are the result of failed maintenance to correct Unit 2 RPV head closure bolt #33. The licensees strategy, as provided in the LAR, is to discontinue monitoring the condition of closure bolt #33 and any new emergent single closure bolt issues for the life of the plant. Despite regulatory relief in 2017 and 2109, the licensee has failed to develop and execute a plan for corrective action. Instead, the licensee intends to exclude closure bolt #33 and an additional bolt in Unit 2 and a single closure bolt in Unit 1, for which no defects are known presently, from the TS and condition monitoring. If the licensee is excluding equipment as important as the RPV head closure bolts, NRC should be concerned about other yet unknown SSCs that are not receiving the expected maintenance and condition monitoring.

ISSUE 2: RAI-05 is consistent with the 10 CFR 54.37(b) and RIS 2007-16, Revision 1

  • Section (b) of 10 CFR 50.37, Additional records and recordkeeping requirements, states that After the renewed license is issued, the FSAR update required by 10 CFR 50.71(e) must include any systems, structures, and components newly identified that would have been subject to an aging management review or evaluation of time-limited aging analyses in accordance with § 54.21. This FSAR update must describe how the effects of aging will be managed such that the intended function(s) in § 54.4(b) will be effectively maintained during the period of extended operation.

3 Michael T. Markley July 10, 2023

The FSAR update needs to describe how the licensee will manage the effects of aging in order to effectively maintain the intended function(s) in 10 CFR 54.4(b) during the period of extended operation.

  • RAI-05 is applicable to the licensees aging management review and time -limited aging analyses (TLAAs) program and for reporting on newly identified structures, systems, and components (SSCs) that would have been subject to aging management review or as a TLAA in accordance with 10 CFR 54.21. It is not apparent how the licensee is treating or reporting on degraded or inoperable RPV head closure bolts in accordance with 10 CFR 54.
  • The Hatch accident analysis presumes a fully tensioned RPV head in the original design and license. The licensees analysis appears to be overly optimistic in presum ing specific safe locations of further degradation rather analyzing for the most limiting locations that could adversely affect the RPV head O-rings and fission product barrier integrity over the life of the plant.
  • Revision 39 to Updated Safety Analysis Report, Chapters 8 through 18, Appendix A (ML23135A071), Section 18.2.12, Component Cyclic or Transient Limit Program,

states, in part, that The four limiting high stress RPV boundary components are the RPV main closure studs, the RPV shell, the RPV recirculation inlet nozzles, and the RPV feedwater nozzles. As such, the RPV head closure bolts are among the highest stress -

limiting SSCs in the plant.

  • Page 3-36 of NUREG -1803, [2:3] Section 3-1 - Section 3-212, Safety Evaluation Report Related to the License Renewal of the Edwin I. Hatch Nuclear Plant Units 1 and 2 (ML020020291), the NRC safety evaluation states, in part, that Bolting that is heat treated to a high hardness condition and exposed to a humid environment within containment could be susceptible to SCC [stress corrosion cracking]. In response to RAI 3.4-1, the applicant did not state if the yield strength for ASME SA-1 93 (Grade B7) or any other bolts are limited to less than 150 ksi to avoid the possibility of stress corrosion cracking. (See RICSIL No. 055, February 1, 1991, "RPV Head Stud Cracking."). In Open Item 3.1.11-1, the staff requested that the applicant provide this information. By letter dated June 5, 2001, the applicant stated that these bolts were procured with a minimum yield strength of 105 ksi, with no upper limit stated. However, the applicant also stated that it has not experienced problems with these bolts and could not identify any problems during a survey of industry experience. On the basis that the applicant's operating experience has not shown that these bolts have experienced SCC, the staff finds the applicant's response adequate and considers Open Item 3.1.11 - 1 closed.

Clearly, the situation has changed with regard to the condition of the Hatch Unit 2 RPV head closure bolts, and licensee aging management and reporting of these SSCs warrants further evaluation.

4

Retrieved from "https://kanterella.com/w/index.php?title=ML23248A490&oldid=3695869"