ML25013A051
| ML25013A051 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 01/13/2025 |
| From: | Constellation Energy Generation |
| To: | Scott Wall NRC/NRR/DORL/LPL3 |
| Arora, S | |
| References | |
| EPID L-2024-LRM-0151 | |
| Download: ML25013A051 (1) | |
Text
Constellation NRC Pre-Submittal Meeting Request for Exemptions from 10 CFR 50.55a(a)(3)(ii), which incorporates by reference Regulatory Guide 1.147, Revision 21, for Code Case N-921, and 10 CFR 50.55a(y)
Overview of Exemption Request
Background
Basis for Approval of Exemption Request Environmental Considerations Proposed Schedule Meeting Agenda Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 1
In accordance with 10 CFR 50.12, Specific exemptions, Constellation Energy Generation, LLC (CEG), will request NRC approval of exemptions from 10 CFR 50.55a(y), which defines the ISI interval as 10 years by reference to IWA-2431 and 10 CFR 50.55a(a)(3)(ii), which incorporates by reference Code Case N-921 from Regulatory Guide 1.147, Revision 21, with Table 2 condition (2) that limits initial implementation of the American Society of Mechanical Engineers (ASME) Code Case N-921 to the beginning of an inservice inspection (ISI) interval.
The exemption request, if granted, will allow Dresden Nuclear Power Station (Dresden)
Units 2 and 3 and Quad Cities Nuclear Power Station (Quad Cities) Units 1 and 2 to implement ASME Code Case N-921 during the current ISI interval Exemptions are requested for the remainder of each plants extended ISI interval.
Overview of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 2
Code Case N-921 establishes a 12-year ISI interval for inservice inspection programs. The marginal extension from a 10-year to 12-year ISI interval supports a minimum of two refueling outages per period and allows levelized distribution of examinations and tests across all inspection periods.
Condition (2) on Code Case N-921 was added to NRC Regulatory Guide 1.147, Revision 21 in response to an anonymous public comment (ML23235A158 and ML23291A328)
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 3
B-6 Code Case N-921 Implementation Comment Summary B-6: A commenter suggested that the NRC add a condition to require implementation of Code Case N-921 at the beginning of an ISI interval. The commenter stated that implementing the code case mid-ISI interval could lead to extra burden for the NRC and the industry. Specifically, existing alternatives would likely need to be reauthorized by the NRC. The commenter suggested that the NRC should add a condition requiring that Code Case N-921 only be implemented at the start of a new interval, to eliminate these requests. The commenter stated that NRCs regulatory analysis did not provide or address the additional costs associated with updating to the code cases mid-interval for licensees submitting new alternative requests.
(13-2, 13-3)
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 4
NRC Response:
The NRC agrees with the commenter and has added a condition to only allow implementation of Code Case N-921 to occur at the beginning of an ISI interval, rather than allowing implementation during a mid-ISI interval. The NRC agrees that mid-ISI interval implementation of Code Case N-921 would create a significant burden for both the NRC and licensees because of the ongoing schedule for ISI activities and the need to resubmit requests for alternatives authorized based on a 10-year ISI interval. The NRC notes that the ASME BPV Code currently allows a 1-year extension of the 10-year ISI interval with certain conditions, which makes the necessary burden to achieve an extra 1-year ISI interval extension to be of questionable resource value. Licensees wishing to implement Code Case N-921 during a mid-ISI interval should submit an exemption request in accordance with 10 CFR 50.12, Specific exemptions, and should review all NRC-authorized alternative requests to determine whether they need to be resubmitted to the NRC for review and authorization.
As a result of this comment, the NRC added a condition to RG 1.147, Revision 21, to only allow implementation of Code Case N-921 at the beginning of a new ISI interval.
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 5
The Statements of Consideration to the Final Rule reiterate the rational underlying N-921 Condition 2 (Final Rule, ASME Code Cases and Update Frequency, 89 Fed. Reg. 58039, July 17, 2024):
There are complications associated with extending the ISI interval mid-interval. For instance, licensees wanting to extend the ISI interval mid-interval would need to evaluate all NRC-approved alternatives to determine if they should be resubmitted, especially considering that NRC may have granted the alternative assuming a 10-year ISI interval.
Further, Code Case N-921 specifies requirements in terms of three 4-year periods, so licensees would need to reconcile their inspection schedules accordingly. Therefore, this final rule specifies that Code Case N-921 can only be implemented following a routine update of the ISI program (i.e., cannot be implemented mid-interval) and requires the licensees ISI code of record to be the 2017 Edition, or later, of the BPV Code.
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 6
In summary, the NRC identified two distinct concerns with allowing mid-cycle implementation of Code Case N-921:
- Licensees would need to reconcile their inspection schedules to conform with the three 4-year periods specified in Code Case N-921, and
- Licensees would need to evaluate all NRC-approved alternatives to determine if they should be resubmitted.
Additionally, 10 CFR 50.55a(y) was also introduced, adding a definition of Inservice Inspection Interval to state the inspection interval described in Article IWA-2432 of ASME BPV Code,Section XI, 1989 Edition with 1991 Addenda through the 2008 Addenda, or Article IWA-2431 of ASME BPV Code,Section XI, 2009 Addenda and later. This definition creates an inconsistency with application of Code Case N-921.
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 7
Dresden and Quad Cities current ISI intervals started in January 2023 and April 2023, respectively, prior to the incorporation of Regulatory Guide 1.147, Revision 21 into the regulation. The addition of condition (2) after the public comment period prevented CEG from obtaining the planned benefit of Code Case N-921.
CEG proactively acted based on the information publicly available, in anticipated implementation of Code Case N-921 in the new interval. This includes revision of the period start and end dates to accommodate outage schedules and adjusting examination schedules accordingly while maintaining compliance with periodic distribution requirements. The requested exemptions would allow the plants listed in Table 1 to implement Code Case N-921
Background
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 8
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Background===
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 9
Notes:
- 1. ISI - Inservice Inspection; CISI - Containment Inservice Inspection
- 2. The Interval End Date is subject to change in accordance with -2430(c)(1) of Code Case N-921.
Authorized by law This exemption would allow CEG to implement ASME Code Case N-921 at Dresden and Quad Cities during current ISI intervals. The NRC acknowledged the appropriateness of submitting an exemption in its response to public comments noted previously. Granting the proposed exemption will not result in a violation of the Atomic Energy Act of 1954, as amended, and will not present an undue risk to the public health and safety and is consistent with the common defense and security. Therefore, the exemption is authorized by law.
Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 10
Will not present an undue risk to public health and safety The underlying purpose of condition (2) on Code Case N-921 was to prevent extra burden to the NRC and the Licensee regarding ISI program implementation, examination schedule revisions and re-submittal of previously approved Relief Requests. Any potential burden associated with implementing Code Case N-921 impacts time and resources for managing the ISI program and does not impact public health and safety.
Therefore, the exemption will not present an undue risk to public health and safety.
Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 11
Consistent with the common defense and security The proposed exemption would allow CEG to implement ASME Code Case N-921 at Dresden and Quad Cities during the current ISI intervals and has no relation to security.
The proposed exemptions will not adversely affect CEGs ability to physically secure the sites and facilities and to protect special nuclear material. Therefore, the common defense and security is not affected by this exemption.
Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 12
Special circumstances are present Criterion ii - Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule.
Criterion iii - Compliance would result in undue hardship or other costs that are significantly in excess of those contemplated when the regulation was adopted Criterion vi - There is present any other material circumstance not considered when the regulation was adopted for which it would be in the public interest to grant an exemption Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 13
Generally speaking, the purpose of the 2024 rulemaking adopting the current provisions of 10 CFR 50.55a(a)(3)(ii) is for the NRC to identify new, revised, and reaffirmed ASME code cases that the NRC has determined are acceptable for use as voluntary alternatives to compliance with certain provisions of the ASME BPV Code currently incorporated by reference into the NRCs regulations. The Statements of Consideration to the Final Rule adopting 10 CFR 50.55a(a)(3)(ii) state that [t]he inservice inspection interval and the code of record update interval should be synchronized to promote order and predictability in licensee inservice inspection programs.
Because the concerns identified by the NRC in establishing Condition 2 for Code Case N-921 are not applicable or can be easily mitigated by CEG, the underlying purpose of the rule would continue to be achieved when allowing implementation of Code Case N-921 during the current ISI interval and the special circumstance of 10 CFR 50.12(a)(2)(ii) is present.
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 14
Implementation of Code Case N-921 following the start of the current ISI interval does not inhibit the ability of CEG to comply with code required periodic distribution requirements and allows for a more efficient distribution of examinations and tests throughout the remainder of the extended interval. Currently ASME Section XI divides the 10-year ISI interval into (3) periods, with allowable adjustments described in IWA-2430. Code Case N-921 allows plants to establish consistent four-year periods over the course of a 12-year ISI interval. This will ensure that each inspection period during the 12-year interval will have at least two refueling outages. During the most recent ISI interval update for each of the plants listed in Table 1, CEG established the periods as a 4-4-2 year breakdown so the additional 2 years allowed by N-921 could be added to the third period. The specific period dates and proposed interval dates, with outages, are shown for each Unit in Tables 2 through 5 in the following slides Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 15
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 16 Notes:
- Proposed ISI interval end date for implementation of a 12-yr interval via N-921.
- Proposed last outage for implementation of a 12-yr interval via N-921.
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 17 Notes:
- Proposed ISI interval end date for implementation of a 12-yr interval via N-921.
- Proposed last outage for implementation of a 12-yr interval via N-921.
Regarding the concern that significant burden would result from licensees needing to reconcile their inspection schedules to conform with the three 4 year periods specified in Code Case N-921, this does not create any particular challenge. CEG regularly revises the ISI examination schedule mid-interval. Reasons for revising the ISI examination schedule mid-interval include, but are not limited to, dose, availability of examination equipment and personnel, availability of personnel for required support tasks (e.g. insulation, scaffold, weld preparation), outage schedules, outage duration, changes in operating strategy, etc.
Maintaining the ISI examination schedule, including mid-interval changes, is core business for ISI program owners and implementation of Code Case N-921 mid-interval does not result in a significant burden, contrary to the commenters assertion. As previously mentioned, during the most recent ISI interval update, CEG took specific actions in anticipation of implementation of Code Case N-921 in the new interval. This includes revision of the period start and end dates and adjusting examination schedules accordingly.
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 18
With respect to the need to evaluate previously approved alternates that were based on a 10-year ISI interval, this would not be a significant burden and in fact Constellation has already performed this evaluation. CEG performed a review of all previously authorized alternatives (relief requests) for Dresden and Quad Cities and assessed the impact of extending the interval by 2 years to implement Code Case N-921. The results of this assessment determined that there is no impact to any of the previously approved alternatives. The full assessment of each previously approved alternative and impact of transitioning to a 12-year interval will be included with the exemption request. An Example is provided on next slide.
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 19
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 20
The proposed exemptions will allow implementation of Code Case N-921 for the remainder of the current ISI interval for the plants listed in Table 1. All other conditions associated with Code Case N-921 apply as specified in Regulatory Guide 1.147, Revision 21. The proposed exemptions do not include an alternative to the ASME Section XI requirements to distribute examinations among the three inspection periods and there is no impact on previously approved relief requests.
Criterion ii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 21
Compliance with Section 50.55a(a)(3)(ii) and the related condition imposed on the implementation of Code Case N-921 would result in undue hardship and Special Circumstance 50.12(a)(2)(iii) is present.
The Commission has explained that the application of Criterion iii, undue hardship, is narrow. As the Commission stated in the 1985 rule adopting the current exemption criteria, this special circumstance was intended to provide equitable treatment to applicants or licensees who, because of some unusual circumstance, are affected in a manner different than that of other similarly situated licensees or applicants. Here, however, Constellation will, in fact, be subjected to an undue hardship as a result of the application of Condition 2 to Code Case N-921. Specifically, limiting Constellation from being able to adopt N-921 for Dresden and Quad Cities would result in inequitable treatment because it would be done on a basis that does not apply to these facilities.
Criterion iii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 22
As explained previously, none of the concerns regarding midcycle adoption of N-921 that underlie Condition 2 are applicable to Constellation or can be easily mitigated. Therefore, it would be fundamentally unfair to preclude Constellations ability to implement the useful improvements to the Dresden and Quad Cities inservice inspection programs otherwise permitted by N-921.
Criterion iii: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 23
There are material circumstances that are present and not considered when the NRC modified 10 CFR 50.55a(a)(3)(ii) and adopted the related Condition 2 for implementation of Code Case N-921 and Special Circumstance 50.12(a)(2)(vi) is present.
Specifically, the NRC adopted Condition 2 based on a single comment without an opportunity for the industry to provide additional input on whether, in fact, mid-cycle implementation of Code Case N-921 would result in the significant burden asserted. Had such input been provided, the NRC would have understood a mid-cycle implementation of Code Case N-921 would not create the significant burden that it anticipated. As explained, the concerns underlying this condition do not exist for CEG.
Criterion vi: Basis for Approval of Exemption Request Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 24
CEG has determined that the requested exemptions meet the categorical exclusion provision in 10 CFR 51.22(c)(25), as the requested licensing action is an exemption from the requirements of the Commission's regulation and (i) there is no significant hazards consideration; (ii) there is no significant changes in the types or significant increase in the amounts of any effluents that may be released offsite; (iii) there is no significant increase in individual or cumulative public or occupational radiation exposure; (iv) there is no significant construction impact; (v) there is no significant increase in the potential for or consequences from radiological accidents; and (vi) the requirements from which an exemption is sought involve inspections, scheduling and administrative requirements.
Environmental Consideration Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 25
- January/February 2025 - CEG prepare Exemption Request
- February 2025 - CEG submit Exemption Request
- August 2025 - CEG requested approval Proposed Schedule Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 26
Request for Exemptions from Regulatory Guide 1.147 Condition (2) for Code Case N-921 27 Questions?