ML24214A323

Response to Request for Additional Information - Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations

ML24214A323
Person / Time
Site:	Peach Bottom
Issue date:	08/01/2024
From:	Para W Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
EPID L-2023-LLN-0004
Download: ML24214A323 (1)

Text

200 Energy Way Kennett Square, PA 19348 Constellation www.ConstellationEnergy.com

10 CFR 50.82(a)(3)

August 1, 2024

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Peach Bottom Atomic Power Station, Unit 1 Facility Operating License No. DPR-12 NRC Docket No. 50-171

Subject:

Response to Request for Additional Information - "Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations"

References:

1. Letter from David P. Helker (Constellation Energy Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations," dated October 20, 2023 (ADAMS Accession No. ML23293A305)

2. Letter from David P. Helker (Constellation Energy Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Supplemental Information in Support of Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations," dated May 13, 2024 (ADAMS Accession No. ML24134A179)

3. Electronic mail message from Tanya Hood (U.S. Nuclear Regulatory Commission) to David P. Helker, Constellation Energy Generation, LLC -

"Peach Bottom Atomic Power Station Unit 1 - Request for Additional Information Re: Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations (EPID L-2023-LLN -0004)," dated July 3, 2024 (ADAMS Accession Nos. ML24185A177)

By letter dated October 20, 2023 (Reference 1), Constellation Energy Generation, LLC (CEG) requested an alternative from the decommissioning schedule requirements specified in 10 CFR 50.82(a)(3) to allow the completion of decommissioning for Peach Bottom Atomic Power Station (Peach Bottom), Unit 1, beyond 60 years of permanent cessation of operations. This request is to allow CEG to complete the decommissioning of Peach Bottom Unit 1, in a time frame more suitable with the decommissioning of Peach Bottom, Units 2 and 3, in order to reduce the overall risk and increase the margin to public health and safety, as further discussed in the attachment to this letter.

U.S. Nuclear Regulatory Commission Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 2

By letter dated May 13, 2024 (Reference 2), CEG submitted supplemental information in support of the subject request in response to questions discussed during a U.S. Nuclear Regulatory Commission (NRC) audit conducted at the Peach Bottom Unit 1, facility on April 14, 2024.

In an electronic mail message dated June 21, 2024, the NRC issued a draft Request for Additional Information (RAI) indicating the need for additional information in order for the NRC continue its review and evaluation of the subject licensing action. This draft RAI was the subject of further discussions during a teleconference on July 2, 2024, between CEG and NRC representatives in which additional clarification was provided. The NRC then formally issued the RAI on July 3, 2024 (Reference 3), requesting that CEG respond to the RAI within 30 days of issuance of the formal request.

The Attachment to this letter provides a restatement of the RAI questions cited in Reference 3 followed by CEGs responses.

There are no new regulatory commitments in this response.

If you have any questions or require additional information, please contact Steven Bowers at 267-533-5101.

Respectfully,

Wendi Para Sr. Manager - Licensing Constellation Energy Generation, LLC

Attachment:

Response to Request for Additional Information - Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations

cc: Regional Administrator - NRC Region I w/ Attachment NRC Senior Resident Inspector - Peach Bottom Atomic Power Station NRC Project Manager, NMSS - Peach Bottom Atomic Power Station NRC Project Manager, NRR - Peach Bottom Atomic Power Station Director, Bureau of Radiation Protection - PA Department of Environmental Protection S. Seaman - State of Maryland

ATTACHMENT

Peach Bottom Atomic Power Station, Unit 1 Docket Nos. 50-171

Response to Request for Additional Information - Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations

Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 1 of 7

Attachment

Response to Request for Additional Information - Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations

By letter dated October 20, 2023 (Reference 1), Constellation Energy Generation, LLC (CEG) requested an alternative from the decommissioning schedule requirements specified in 10 CFR 50.82(a)(3) to allow the completion of decommissioning for Peach Bottom Atomic Power Station (Peach Bottom) Unit 1, beyond 60 years of permanent cessation of operations. This request is to allow CEG to complete the decommissioning of Peach Bottom Unit 1, in a time frame more suitable with the decommissioning of Peach Bottom Units 2 and 3, in order to reduce the overall risk and increase the margin to public health and safety, as further discussed in the attachment to this letter.

By letter dated May 13, 2024 (Reference 2), CEG submitted supplemental information in support of this proposed licensing action in response to questions discussed during a U.S. Nuclear Regulatory Commission (NRC) audit conducted at the Peach Bottom Unit 1, facility on April 14, 2024.

In an electronic mail message dated June 21, 2024, the NRC issued a draft Request for Additional Information (RAI) indicating the need for additional information in order to continue its review and evaluation of the alterative decommissioning schedule request for Peach Bottom Unit 1. This draft RAI was the subject of further discussions during a teleconference on July 2,

2024, between CEG and NRC representatives in which additional clarification was provided. The NRC then formally issued the RAI on July 3, 2024 (Reference 3), requesting that CEG respond to the RAI within 30 days of issuance of the formal request.

Below is a restatement of the RAI questions cited in Reference 3 along with CEGs response following each of the questions.

RAI 1

In the supplement, the licensee indicated that Peach Bottom Unit 1 was not designed to support vessel flooding and requires a unique approach to be developed to accomplish dismantlement.

The staff notes that this position does not involve the presence of other nuclear facilities at the site. Explain why a delay is necessary to protect public health and safety given that the licensee has had since 1974 to plan decommissioning.

CEG Response:

As described in the current Peach Bottom Unit 1 Decommissioning Cost Estimate (DCE),

planning in support of a 2034 license termination would begin in 2023, just over ten years prior to license termination. CEG began evaluating the decommissioning of Peach Bottom Unit 1 in late 2021. During this initial evaluation phase, CEG identified irradiated graphite removal and disposal issues that were more problematic than previously thought.

Before 2023, the decommissioning timeline did not include detailed evaluations for Peach Bottom Unit 1. Moreover, the methods for irradiated graphite removal have recently undergone Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 2 of 7

significant evolution due to recent research and development (R&D) programs in progress in Europe. This progress means that evaluations from decades ago likely no longer apply to today's decommissioning processes.

Since 2021, CEG has been actively engaged in extensive research by EPRI and universities such as Boise State and the Institute of Nuclear and Energy Technology in Beijing, National Laboratories such as Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Idaho National Laboratory as well as research provided by the International Atomic Energy Agency graphite knowledge base (this list is not exhaustive) to identify potential issues and mitigative methods related to the removal and disposal of irradiated graphite. The results of this ongoing research were presented in the response to Question 8 of the CEG S upplemental Response (Reference 2), reflecting CEGs commitment to finding the best solutions for these challenges. Although research has produced some methods for removal and disposal of irradiated graphite, these methods must be carefully reviewed against the circumstances specific to Peach Bottom Unit 1, as the design and age of Peach Bottom Unit 1 distinguish it from other sources of irradiated graphite. As an example, one EPRI mitigative method is gasification of graphite but this method must be performed upon unit shutdown ( References 4 and 5). This method would not be an option for Peach Bottom Unit 1 due to the length of time since Peach Bottom Unit 1 shutdown.

Additional time is necessary because the irradiated graphite used in the operation of this test reactor presents unique challenges to decommissioning. Although CEG has worked to identify and define the potential issues associated with irradiated graphite removal and disposal, solutions to these issues are still being developed and subsequently must be confirmed to be viable for Peach Bottom Unit 1. Updated methods for graphite removal and disposal are becoming available as the worldwide nuclear industry addresses this challenge, and the examination of this operating experience as it becomes available is crucial for CEG and the industry to develop the best option for graphite removal and disposal with respect to maintaining public health and safety.

RAI 2

In the supplement, the licensee indicated that reasonable mitigation to protect public health and safety that would allow Peach Bottom Unit 1 to safely decommission using available conventional methods could not be identified. Provide a clear, concise justification that indicates how using available mitigation methods poses a significantly increased risk to public health and safety that would necessitate an alternative schedule because the licensee would not be able to maintain compliance with health, safety, and security regulations. Quantify the risks to the extent possible.

CEG Response:

Because of the unique design of the Peach Bottom Unit 1 reactor vessel and internals, a customized approach must be developed for demolition and decommissioning (D&D). Currently, CEG does not know of a suitable mitigation method to perform D&D on the Peach Bottom Unit 1 reactor vessel and reactor vessel internals (RV/RVIs). CEG has not identified a successful method to grout and remove graphite containing reactor vessels and internals, and the known and normal method for decommissioning, including irradiated graphite removal, utilizes underwater mitigation. The use of water as a dose barrier significantly reduces the risk of Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 3 of 7

contamination and radiation exposure, however due to the design of the reactor, underwater mitigation is not available for use with Peach Bottom Unit 1. Customized mitigation methods must be developed to minimize the risk to public health and safety. Moreover, the lack of laydown area would not allow for other standard radiation minimization methods to be utilized, such as building a tent outside containment to decontaminate components as they are removed.

This would add further risk to public health and safety. Note, this particular challenge is only present while Peach Bottom Units 2 and 3 are still in operation, because areas which are currently actively used by the site could be repurposed after the operating units are shut down.

As previously stated, CEG believes that the research being conducted within the global nuclear industry will produce new mitigation methods for irradiated graphite in the near future. These methods, while not yet officially implemented on a decommissioning project, are being activ ely pursued and hold promise for the safe and successful decommissioning of Peach Bottom Unit 1.

RAI 3

In the supplement, the licensee speculates that suitable decommissioning methods will be developed for High-Temperature Gas -Cooled Reactors (HTGRs) in the near future based on global decommissioning efforts but provides no reference to any studies, ongoing work, or agreements with other parties to include the issues at Peach Bottom Unit 1. Explain how Constellation is engaged with research on a global scale to establish suitable decommissioning methods for HTGRs. Provide references and contacts to the establishments and organizations that Constellation is working with on this effort.

CEG Response:

As noted in the Reference 2 Supplemental Response, CEG began efforts regarding High Temperature Gas-Cooled Reactor (HTGR) decommissioning methods in late 2021 by working with EPRI USA as well as conducting vast research as discussed in the CEG response to RAI 1,

above. In 2005, EPRI USA began a worldwide collaborative program utilizing leading worldwide specialists to address issues related to the significant decommissioning challenge of removal and disposal of irradiated graphite. The EPRI program supported the completion of technical reports in 2010 which identified some of the significant issues associated with decommissioning a gas cooled graphite moderated reactor with specific technical challenges identified for further study (References 4 and 5).

While reviewing the EPRI R&D program results, CEG contracted with three separate decommissioning vendors from 2022 to 2023 to obtain a suggested process to remove the Peach Bottom Unit 1 RV/RVIs. Although high-level decommissioning plans were provided, all contractors identified that decommissioning Peach Bottom Unit 1 would require a unique plan due to the nature of irradiated graphite and the inability to flood the vessel, and more research was required before the appropriate method could be selected that would best protect the public health and safety.

Because the decommissioning vendors confirmed the need for customized methods that would be suitable for Peach Bottom Unit 1, CEG began working with EPRI Europe by reviewing European efforts to date including various presentations and reports to ascertain the status of the European decommissioning efforts as EPRI USA has not engaged in graphite decommissioning analysis since the 2010-2012 timeframe.

Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 4 of 7

CEG has identified through engagements with EPRI Europe that as of 2023, R&D is in progress in France such that suitable methods may become available for use in decommissioning graphite moderated HTGRs in the future. This information was previously provided in the response to Question 8 of the CEG Supplemental Response (Reference 2).

During this period of review, CEG has also had a vendor complete an updated analytical neutron activation analysis (NAA). Additionally, a contract has been established to develop a sampling plan of the reactor vessel and internals to benchmark the results of the analytical NAA.

CEG's next step is to benchmark the European R&D progress and results to date and evaluate the feasibility for use with Peach Bottom Unit 1.

RAI 4

In the1996 Decommission Cost Study for Peach Bottom Unit 1, the strategy was to remove the Unit 1 reactor internals by cutting a hole in the containment dome and removing the reactor and internals from the top using a crane. NRC assumes that radiological engineering and administrative controls would be used as needed. Why is the strategy proposed in 1996 not feasible?

CEG Response:

The DCE is not used for detailed planning on how a unit will be decommissioned, but rather a high-level estimate of the cost. Certain assumptions need to be made about the decommissioning process to develop a DCE, and the DCE does not include any detailed engineering analyses or studies for reactor vessel removal, but instead assumes more generic industry methods are used. To determine the actual decommissioning option more detailed analysis needs to be completed. The ability to flood the vessel for reactor vessel internals removal, a standard decommissioning process, is not available for Peach Bottom Unit 1.

However, the learnings from EPRI USA analyses in the early 2000s, particularly those related to issues with irradiated graphite, were crucial. These analyses, which CEG could not benefit from then because they had not been developed, have since become a cornerstone in the understanding of the decommissioning process for irradiated graphite.

More is now known about the unique challenges associated with the D&D of irradiated graphite due to the issues at Fort St. Vrain and worldwide studies (Reference 2). These studies show that it is more complex than grouting the vessel and removing the RV/RVI as an entire package for disposal. CEG will use this information to help inform decision making on the appropriate plan to ensure the health and safety of workers and the public.

Additionally, at the time the 1996 DCE was prepared for Peach Bottom Unit 1, the Peach Bottom Units 2 and 3 licenses were set to expire in 2013 and 2014, respectively. With the understanding that Peach Bottom Units 2 and 3 would be shut down there would have been ample time to complete concurrent decommissioning of all three units before the 60-year license termination requirement for Unit 1 was reached. Consequently, the Peach Bottom Unit 1 1996 DCE only discusses concurrent decommissioning of the three units and does not mention any contingencies or mitigative measures needed for decommissioning of Peach Bottom Unit 1 while Peach Bottom Units 2 and 3 continue to operate.

Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 5 of 7

Based on what is known today versus 1996 regarding issues associated with irradiated graphite, the learnings from Fort St. Vrain, and the inability to identify a method to grout a vessel with graphite as a D&D method selected by other utilities that require a graphite-moderated reactor demolition, CEG will need to evaluate all options to safely decommission Peach Bottom Unit 1.

RAI 5

If the Peach Bottom Unit 1 reactor cannot be decommissioned using DECON for unrestricted release, other decommissioning methods are available such as restricted release and entombment. Explain why other methods are not being considered.

CEG Response:

In 2021, as part of CEGs commitment to addressing the irradiated graphite issue, CEG evaluated Peach Bottom Unit 1 for various decommissioning options. Based on the information gathered, including the European R&D of new methods, CEG believes Peach Bottom Unit 1 will be a successful candidate for unrestricted release.

To meet the requirements for restricted release, the reactor vessel and internals would still need to be removed, so it does not solve the issues described above with vessel flooding and graphite removal and disposal.

Entombment was not considered a viable option for several reasons. First, while it is mentioned in NRC documents as a possibility, there is no regulatory framework or precedent for this option.

Second, the current issues with space limitations around the Peach Bottom Unit 1 containment would make this a more complicated and costly operation, which could lead to additional risk to health and safety of the workers and the public. Finally, there would be a significant increase in overall cost, as the entombment would have to be maintained over time, and then removed during the ultimate decommissioning of Peach Bottom Units 2 and 3 to allow for unrestricted release of the site at that time. This additional cost and scope could jeopardize the funding assurance for Peach Bottom Unit 1. Therefore, this option does not provide any benefit over extending the 60-year requirement, and significantly increases cost and risk.

Considering that Peach Bottom Units 2 and 3 will eventually be decommissioned for unrestricted release, it would not be advantageous for the health and safety of the public or the community as a whole to maintain Peach Bottom Unit 1 in a restricted or entombed condition.

RAI 6

If the licensee believes that the Peach Bottom Unit 1 reactor cannot be safely decommissioned, then explain why annual decommissioning cost estimates and the Generic Environmental Impact Statement for Decommissioning Reactors, NUREG -0586, Supplement 1 Volume 2 infer otherwise?

Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 6 of 7

CEG Response:

As described in the response to RAI 4, the DCE is not a detailed engineering analysis, but instead is a high-level estimate of the costs based on standard industry practices. More detailed planning and evaluation is done closer to the time of actual decommissioning, which is what happened in this case. The DCE does not make any evaluation of the best way to protect the health and safety of the public or the workers, and this cannot be inferred from the document.

NUREG-0586, Supplement 1 Volume 2 is dated 2002, and is comprised of responses from the NRC staff to comments received during the approval process for the NUREG. The following comment is documented:

Exelon believes the proposed Draft Supplement correctly concludes that most of the environmental issues assessed result in impacts that are generic and SMALL for all plants. We reach this conclusion based upon our experience during decommissioning one BWR (Dresden 1), two PWRs (Zion Station), one HTGR (Peach Bottom 1), and our observation of other industry decommissioning projects. We have not seen to date - and currently do not expect to find - environmental impacts different from those addressed and bounded by this Supplement to the GEIS

This comment refers to past decommissioning experience gained, in part, from decommissioning work that was completed at Peach Bottom Unit 1 while placing the unit a SAFSTOR condition. This statement is not commenting on the safety aspects of transitioning Peach Bottom Unit 1 from SAFSTOR to license termination.

Furthermore, Section 3.3.2 of NUREG-0586, Supplement 1 states that In most cases, SAFSTOR was chosen so that all units on a site could be decommissioned simultaneously which does not infer that decommissioning Peach Bottom Unit 1 while Peach Bottom Units 2 and 3 are still operating is the best way to protect the health and safety of the public.

Additionally, the difficulties presented within CEG s request and supplement (Reference 2) are based on considerations other than environmental impacts. CEGs request to extend the license termination date is not because of anticipated environmental challenges.

As stated in the original request, t he conclusions presented in NUREG -0586, Supplement 1, are unaffected by an extended SAFSTOR period. Additional site-specific environmental impact analysis will be performed for Peach Bottom Unit 1, upon commencement of decommissioning activities, as required.

Attachment Response to Request for Additional Information Alternate Decommissioning Schedule August 1, 2024 Page 7 of 7

References:

1. Letter from David P. Helker (Constellation Energy Generation Company, LLC) to U.S.

Nuclear Regulatory Commission - "Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations," dated October 20, 2023 (ADAMS Accession No. ML23293A305)

2. Letter from David P. Helker (Constellation Energy Generation Company, LLC) to U.S.

Nuclear Regulatory Commission - "Supplemental Information in Support of Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations," dated May 13, 2019 (ADAMS Accession No. ML24134A179)

3. Electronic mail message from Tanya Hood (U.S. Nuclear Regulatory Commission) to David P. Helker, Constellation Energy Generation, LLC - "Peach Bottom Atomic Power Station Unit 1 - Request for Additional Information Re: Request for Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations (EPID L-2023-LLN-0004)," dated July 3, 2024 (ADAMS Accession Nos. ML24185A177 and ML24185A178)

4. EPRI 1013091 Final Report, Graphite Decommissioning Options for Graphite Treatment, Recycling, or Disposal, including a discussion of Safety -Related Issues, March 2006

5. EPRI 1021110 Final Report, Innovative Graphite Removal Technology for Graphite Moderated Reactor Decommissioning Nibble-and-Vacuum, September 2010