ML22074A027

TMI 1 ISFSI Emergency Plan Only SER Input

ML22074A027
Person / Time
Site:	Three Mile Island, 07200077
Issue date:	04/07/2022
From:	Amy Snyder Reactor Decommissioning Branch
To:	Rhoades D Constellation Energy Generation
Snyder A
Shared Package
ML22074A024	List: ML22074A025 ML22074A026 ML22074A027
References
EPID L-2021-LLA-0036
Download: ML22074A027 (14)

Text

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR SECURITY AND INCIDENT RESPONSE RELATED TO AMENDMENT NO. 303 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-50 CONSTELLATION ENERGY GENERATION, LLC THREE MILE ISLAND NUCLEAR STATION, UNIT 1 DOCKET NOS. 50-289 AND 72-77

1.0 INTRODUCTION

Three Mile Island Nuclear Station (TMI) is located in an area of low population density about 12 miles southeast of Harrisburg, Pennsylvania. The area is in Londonderry Township, Dauphin County, about 2.5 miles from the southern tip of Dauphin County, where the county is coterminous with York and Lancaster Counties. The TMI site is part of an 814-acre tract consisting of the Three Mile Island land mass and several adjacent islands, which were purchased by a predecessor. The island, which is situated about 900 feet from the east bank and approximately one mile from the west bank of the Susquehanna River, is elongated parallel to the flow of the river with its longest axis oriented approximately due north and south. The north and south ends of the island have access bridges, which connect the island to State Highway Route 441. Constellation Energy Generation, LLC (Constellation, the licensee) is the holder of Renewed Facility Operating License No. DPR-50, issued pursuant to the Atomic Energy Act of 1954, as amended, and Part 50, Domestic Licensing of Production and Utilization Facilities, of Title 10 of the Code of Federal Regulations (10 CFR).1 By letter dated June 20, 2017 (Reference 1), pursuant to 10 CFR 50.82(a)(1)(i), Exelon Generation Company, LLC (Exelon) certified to the NRC that TMI, Unit 1(TMI-1) would permanently cease power operations on or about September 30, 2019. Subsequently, Exelon permanently ceased power operations at TMI-1 on September 20, 2019. By letter dated September 26, 2019 (Reference 2), pursuant to 10 CFR 50.82(a)(1)(ii), Exelon certified that fuel had been permanently removed from the reactor vessel. Upon docketing of the certifications, the TMI-1 operating license no longer authorized operation of the reactor or emplacement or retention of fuel into the reactor vessel.

1 TMI, Unit 2 (TMI-2), has a possession-only license and is currently maintained in accordance with the U.S. Nuclear Regulatory Commission (NRC) approved SAFSTOR condition (a method in which a nuclear facility is placed and maintained in a condition that allows it to be safely stored and subsequently decontaminated) known as Post-Defueling Monitored Storage. All spent fuel has been removed except for some debris in the reactor coolant system. The removed fuel is currently in storage at Idaho National Laboratory, and the U.S. Department of Energy has taken title and possession of the fuel. Constellation maintains the emergency planning responsibilities for TMI-2, which is owned by TMI-2 Solutions, through a service agreement.

By application dated March 4, 2021 (Reference 3), as supplemented by letter dated August 30, 2021 (Reference 4), Exelon requested prior approval by the NRC of the proposed TMI Independent Spent Fuel Storage Installation (ISFSI) Only Emergency Plan (TMI Station EP) and associated emergency action level (EAL) Scheme Technical Bases Document, to support the planned transfer of the spent fuel from the TMI-1 spent fuel pools (SFPs) to the ISFSI. In the March 4, 2021, application, Exelon wrote that:

Three Mile Island, Unit 2 (TMI-2), has a possession only license and is currently maintained in accordance with the NRC approved SAFSTOR condition (method in which a nuclear facility is placed and maintained in a condition that allows it to be safely stored and subsequently de contaminated) known as Post-Defueling Monitored Storage (PDMS). Exelon maintains the emergency planning responsibilities for TMI-2, which is owned by TMI-2 Solutions, through a service agreement. This License Amendment Request (LAR) does not impact Exelon's ability to maintain the service agreement.

In addition, Exelon references the TMI-2 docket number, 50-298, in the application request.

This SER does not, however, does not address the TMI-2 proposed changes EP and EAL as identified in its January 7, 2022, letter (ADAMS Accession No. ML22013A177). TMI-2 Solutions will address these changes through a separate licensing proceeding.

The proposed changes would reflect the decommissioning status of the facility, as well as the reduced scope of potential radiological accidents, once all spent fuel has been moved from the SFPs to dry cask storage within the onsite ISFSI, which is currently scheduled for completion on or about July 2022.

Exelon submitted a supplement a dated August 30, 2021. The supplement provided additional information that clarified the application, but did not expand the scope of the application as originally noticed and did not change the NRC staff's original proposed no significant hazards consideration determination as published in the Federal Register (FR) on April 20, 2021 (86 FR 20526).

On November 16, 2021, the NRC issued an Order Approving Transfer of Exelon Fleet Licenses and Draft Conforming License Amendments (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21277A248). On February 1, 2022, Constellation notified the NRC that Exelon changed its name to Constellation and the indirect transfer of the cited licenses, to include TMI-1, located in Dauphin County, PA, was completed on February 1, 2022 (ADAMS Accession No. ML22032A333). Also, in the February 1, 2022, letter, Constellation stated that:

Prior to the indirect license transfers, Exelon made docketed submittals to the NRC that requested specific licensing actions, such as license amendment requests, relief requests, exemption requests, etc. This letter requests that the NRC continue to process all pending licensing actions on the schedules previously requested by Exelon.

On February 1, 2022, a conforming amendment, License Amendment No. 302 (ADAMS Accession No. ML22021B660), was issued for Renewed Facility Operating License No. DPR-50 for the TMI-1, to reflect Constellation as the licensee.

2.0 REGULATORY EVALUATION

This safety evaluation addresses the acceptability of the proposed TMI Station EP and associated EAL scheme. This plan would replace the existing TMI Permanently Defueled Emergency Plan (PDEP) and associated Permanently Defueled EALs after all spent fuel has been transferred from the SFPs to dry cask storage within the onsite ISFSI.

Exelon states that the TMI Station EP addresses the applicable regulations stipulated in 10 CFR 50.47, Emergency Plans and 10 CFR 50, Appendix E, Emergency Planning and Preparedness for Production and Utilization Facilities (as previously exempted by the NRC in letter dated December 1, 2020 (Reference 5)), and is consistent with regulations in 10 CFR 72.32 and applicable guidelines established in NUREG-0654/FEMA-REP-1, Revision 1, Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants (Reference 6).

The major changes of the proposed TMI Station EP and associated EAL scheme from the PDEP and associated permanently defueled EALs were reviewed to meet the following regulations, as exempted:

10 CFR 50.47(b)(1), as exempted, states, in part: ... each principal response organization has staff to respond and to augment its initial response on a continuous basis.

10 CFR 50.47(b)(2) states, in part: ... adequate staffing to provide initial facility accident response in key functional areas is maintained at all times, timely augmentation of response capabilities is available....

10 CFR 50.47(b)(4), as exempted, states, in part: A standard emergency classification and action level scheme, the bases of which include facility system and effluent parameters, is in use by the nuclear facility licensee.

10 CFR Part 50, Appendix E, Section IV.A, as applicable, states, in part: The organization for coping with radiological emergencies shall be described, including definition of authorities, responsibilities, and duties of individuals assigned to the licensees emergency organization.

10 CFR Part 50, Appendix E, Section IV.C.1, as exempted, states, in part: the emergency classes defined shall include: (1) Notification of unusual events, [and] (2) alert.

The associated guidance documents on which the NRC based its evaluation and acceptance of the proposed TMI Station EP and associated EAL scheme are as follows:

Revision 1 to NUREG-0654/FEMA-REP-1, which provides a common reference and guidance source for nuclear facility operators to develop radiological emergency response plans.

Office of Nuclear Security and Incident Response / Division of Preparedness and Response (NSIR/DPR) Interim Staff Guidance (ISG) - 2, Emergency Planning

Exemption Requests for Decommissioning Nuclear Power Plants (Reference 7),

which provides guidance for the review of permanently defueled emergency plans for power reactor sites undergoing decommissioning.

NUREG-2215, Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities (Reference 8), which provides emergency plan review guidance applicable to facilities licensed pursuant to the regulatory requirements found in 10 CFR Part 72, Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High Level Radioactive Waste, and Reactor-Related Greater Than Class C Waste.

Nuclear Energy Institute (NEI) document NEI 99-01, Revision 6, Development of Emergency Action Levels for Non-Passive Reactors (Reference 9), which was endorsed by the NRC in a letter dated March 28, 2013 (Reference 10), as generic (non-plant specific) EAL scheme development guidance.

3.0 TECHNICAL EVALUATION

The NRC staff has reviewed Exelons regulatory and technical analyses in support of its proposed emergency plan changes, as described in the application dated March 4, 2021, as supplemented by letter dated August 30, 2021. The technical evaluation is detailed below.

3.1 Background

By letter dated July 1, 2019 (Reference 11), as supplemented by letters dated October 9, 2019 and December 10, 2019 (References 12 and13, respectively), Exelon requested exemptions for TMI from certain emergency plan requirements. By letter dated December 1, 2020, the NRC approved the requested exemptions. By letter dated December 2, 2020 (Reference 14), the NRC approved the TMI PDEP and associated Permanently Defueled EAL scheme. By letter dated January 20, 2021 (Reference 15), Exelon stated that the TMI PDEP and associated Permanently Defueled EAL scheme were fully implemented on that date.

3.2 Proposed Changes In its application dated March 4, 2021, as supplemented by letter dated August 30, 2021, Exelon requested that the NRC review and approve a proposed TMI Station EP, which included an ISFSI-Only EAL scheme based on the applicable guidance in NEI 99-01, Revision 6. The proposed amendment would replace the existing PDEP and associated Permanently Defueled EAL scheme.

The ISFSI at the TMI facility is constructed and TMI-1 is in the process of conducting its spent fuel transfer campaign. This campaign is anticipated to be complete on or about July 2022.

Specifically, the proposed changes would modify the scope of onsite emergency preparedness measures to reflect the reduced potential for radiological accidents with all spent fuel in dry cask storage within the onsite ISFSI. The off-normal events and accidents addressed in the TMI Station EP are related to the dry cask storage of spent nuclear fuel at the ISFSI and include only off-normal, accident, natural phenomena, and hypothetical events and consequences affecting the TMI-1 ISFSI.

The major changes that Exelon is requesting are: (1) removal of non-ISFSI events from EAL scheme; (2) replacement of the Shift Manager with the ISFSI Shift Supervisor; (3) revision to the Emergency Response Organization (ERO).

Under the TMI PDEP with spent fuel stored within the SFPs, the most severe postulated beyond-design-basis accident involved a highly unlikely sequence of events that causes a heat-up of the spent fuel, postulated to occur without heat transfer, such that the zirconium alloy fuel cladding reaches ignition temperature. While this scenario was shown to be highly improbable, based on TMIs calculations in support of the PDEP, as verified by the NRC staff, the resultant zirconium alloy fire could potentially lead to the release of fission products to the atmosphere.

However, after removal of the spent fuel from the TMI SFPs, the accident scenarios and analyses demonstrate that the age and configuration of spent fuel stored in dry cask storage precludes the possibility of such a zirconium alloy fire scenario. As such, after all the spent fuel is transferred to dry cask storage within the onsite TMI ISFSI, the number and severity of potential radiological accidents is significantly less than when spent fuel was stored in the SFPs.

For these reasons, the potential radiological consequences of accidents possible at TMI after all spent fuel is transferred to the ISFSI are further reduced.

There continues to be no need for formal offsite radiological emergency preparedness plans under 44 CFR Part 350, Review and Approval of State and Local Radiological Emergency Plans and Preparedness, at TMI because no design-basis accident or reasonably credible beyond-design-basis accident can result in radioactive releases that exceed the U.S. Environmental Protection Agency (EPA) early phase protective action guides (PAGs)

(Reference 16) beyond the exclusion area boundary.

3.3 Evaluation The NRC staff reviewed the changes from the current TMI PDEP and associated Permanently Defueled EAL scheme to the proposed TMI Station EP and EAL scheme, including Exelons evaluation of the changes, to verify that the proposed TMI Station EP and EAL scheme continue to meet the standards contained in 10 CFR 50.47(b) and the requirements of Appendix E to 10 CFR Part 50, as exempted, for the long-term defueled conditions at TMI. The NRC staff also performed a review to ensure that the proposed TMI Station EP would be consistent with the requirements of 10 CFR 72.32(a). Although the requirements of 10 CFR 72.32(a) do not apply to a 10 CFR Part 50 facility, such as TMI, the NRC examined these regulations to promote consistency in the emergency planning requirements between specifically licensed (Part 72) and generally licensed (Part 50) ISFSIs. These requirements, and their applicability to facilities licensed under 10 CFR Part 72, are further described in NUREG-2215.

3.3.1 Removal of Non-ISFSI Events from EAL Scheme After all fuel is removed from the SFPs, there will no longer be any potential for the accidents previously described in the PDEP associated to SFP operation that would increase risk to the health and safety of the public. These accidents included events specifically related to the storage of the spent fuel in the SFPs. Exelon provided that the off-normal events and accidents addressed in the TMI Station EP are related to the dry storage of irradiated nuclear fuel within the TMI-1 ISFSI and include only the off-normal, accident, natural phenomena, and hypothetical events and consequences presented in the Final Safety Analysis Report for the standardized NAC MAGNASTOR Cask System Certificate of Compliance No. 1031 (Reference 17). After the transfer of the spent fuel from the SFPs to dry cask storage within the onsite ISFSI, the spent

fuel storage and handling systems associated with the SFPs will be removed from operation.

Therefore, accident conditions associated with the SFPs will no longer be applicable.

The initiating conditions (ICs) and EALs associated with the emergency classification levels in the current PDEP are based on Appendix C, Permanently Defueled Station ICs/EALs, to NEI 99-01, Revision 6, which addresses a nuclear power reactor that has permanently ceased operations and transferred spent fuel from the reactor vessel to the SFPs (permanently defueled). After all spent fuel has been removed from the SFPs and placed in dry cask storage within the ISFSI, the ICs and EALs in Appendix C to NEl 99-01, which are associated with the SFPs at a decommissioning facility, are no longer required. Additionally, certain ICs and EALs, whose primary function is not associated with the SFPs, are no longer required when administrative controls are established to limit source term accumulation and the offsite consequences of uncontrolled effluent releases.

Examples of administrative controls for radiological source term accumulation limits and methods to control the accidental dispersal of the radiological source are:

limits on radioactive materials collected on filter media and resins (dose rate limit);

limits on contaminated materials collected in shipping containers (dose rate limit);

limits on surface or fixed contamination on work areas that may create airborne radioactive material (activity limits), and limits on dispersal mechanisms that may cause a fire (e.g., limits on combustible material loading, use of a fire watch to preclude fires, etc.) or placement of a berm around a radioactive liquid storage tank.

Examples of potential methods to control accidental dispersal of the radiological source term include limits on dispersal mechanisms that may cause a fire (e.g., limits on combustible material loading, use of a fire watch to preclude fires, etc.), placement of a berm around a radioactive liquid storage tank, and packaging radioactive materials within confined boundaries with ventilation controls established.

Other ICs proposed for deletion include those associated with the SFP mitigative strategies contained in certain TMI-1 license conditions, as well as response procedures for potential or actual aircraft attacks. The NRC staff has previously maintained EALs for potential or actual aircraft threats for facilities transitioning into decommissioning with spent fuel stored in an SFPs, as well as maintaining the mitigative strategies license conditions. These will be eliminated after spent fuel is removed from the SFPs and is in dry cask storage within the onsite ISFSI.

The proposed deletions of ICs from the proposed EAL scheme for TMI-1 are shown in strikeout in the table below. The deletions are appropriate because either (1) the ICs are associated solely with TMI-1 SFP operations, or (2) for those ICs whose primary function is not associated with the SFPs, sufficient administrative controls to limit possible effluent releases have been established. The ICs and EALs being deleted in their entirety include all ICs and EALs associated with the categories of abnormal radioactivity release and system malfunction, as these two categories apply only to SFP operation.

Emergency Plan Initiating Conditions Being Deleted ALERT UNUSUAL EVENT PD-RA1 Release of gaseous or liquid PD-RU1 Release of gaseous or liquid radioactivity resulting in offsite dose greater radioactivity greater than 2 times the ODCM than 10 mRem TEDE [Total Effective Dose [offsite dose calculation manual]

Equivalent] or 50 mRem thyroid CDE limits for 60 minutes or longer.

[committed dose equivalent].

PD-RA2 UNPLANNED rise in facility PD-RU2 UNPLANNED rise in facility radiation levels that impedes facility access radiation levels.

required to maintain spent fuel integrity.

PD-MU1 UNPLANNED spent fuel pool temperature rise.

PD-HA1 HOSTILE ACTION within the TMI-1 PD-HU1 Confirmed SECURITY CONDITION ISFSI OWNER CONTROLLED AREA or or threat.

airborne attack threat within 30 minutes is occurring or has occurred. EAL:

EAL: 1. Notification of a credible security threat directed at the site as determined per

1. A validated notification from NRC of SY-AA-101-132, Security Assessment an aircraft attach threat <30 minutes and Response to Unusual Activities.

from the site. OR OR 2. A validated notification from the NRC

2. Notification by the Security Force that providing information of an aircraft a HOSTILE ACTION is occurring or threat.

has occurred within the TMI-1 ISFSI OR OWNER CONTROLLED AREA. 32. Notification by the Security Force of a SECURITY CONDITION that does not involve a HOSTILE ACTION.

PD-HU2 Hazardous Event affecting equipment necessary for spent fuel cooling.

PD-HA3 Other conditions exist which in the PD-HU3 Other conditions exist which in the judgment of the Emergency Director warrant judgment of the Emergency Director warrant declaration of an ALERT. declaration of an UNUSUAL EVENT.

E-HU1 Damage to a loaded cask CONFINEMENT BOUNDARY.

EAL:

Damage to a loaded cask CONFINEMENT BOUNDARY as indicated by a radiation reading > 2 times the ISFSI Technical Specification allowable level.

For a facility in which all spent fuel is stored in the ISFSI, the conditions addressed in PD-HU2 remain fully addressed by IC E-HU1.

The ICs listed in the table below are to be retained since they remain appropriate to address an event related to an ISFSI-only facility (i.e., no spent fuel stored in the SFPs).

ISFSI Emergency Plan Initiating Conditions ALERT UNUSUAL EVENT Independent Spent Fuel Storage Installation E-HU1 Damage to a loaded cask CONFINEMENT BOUNDARY.

Hazards and Other Conditions PD-HA1 HOSTILE ACTION within the PD-HU1 Confirmed SECURITY CONDITION TMI-1 ISFSI is occurring or has occurred. or threat.

PD-HA3 Other conditions exist which in the PD-HU3 Other conditions exist which in the judgment of the Emergency Director warrant judgment of the Emergency Director warrant declaration of an ALERT. declaration of an UNUSUAL EVENT.

The most severe beyond-design-basis accident postulated for TMI-1 with spent fuel stored within the SFPs involved a highly unlikely sequence of events that causes heat-up of the spent fuel, postulated to occur without heat transfer, such that the zirconium alloy fuel cladding reaches ignition temperature. Because this limiting, beyond-design-basis scenario is no longer possible due to the transfer of spent fuel from the SFPs to dry cask storage in the onsite ISFSI, Exelons assessment focused on the following design-basis accidents associated with the performance of decommissioning activities with all irradiated fuel stored in the TMI-1 ISFSI:

(1) cask events (fuel related event); (2) radioactive material handling accident (non-fuel related event); and (3) accidents initiated by external events.

As discussed in the December 1, 2020, exemptions from certain emergency planning requirements for TMI, an analysis of the potential radiological impact of a design-basis accident at TMI in a permanently defueled condition indicated that any releases beyond the exclusion area boundary were below the EPA early phase PAGs. The basis for these exemptions has not changed and remains in effect for the proposed emergency plan changes.

For design-basis accidents (1) and (2) cited in the paragraph above, the results of Exelons assessment indicate that the projected radiological doses at the exclusion area boundary continue to be less than the EPA early phase PAGs. The effects of accidents initiated by external events, (3) cited above, such as fires, flood, wind (including tornadoes), earthquakes, lightning, and physical security breaches on the TMI-1 ISFSI that could affect the confinement boundary of the ISFSI, remain unchanged from the effects that were considered under the PDEP. The NRC staff examined the assumptions used in Exelons analyses and verified that inputs were more conservative than those used in the approved PDEP, and therefore, determined that the associated accident analyses are sufficient to conclude that any releases beyond the exclusion area boundary will be below EPA early phase PAGs.

Because of the very low risk of consequences to public health and safety resulting from the postulated accidents related to the TMI-1 ISFSI, potential emergencies continue to be classified no higher than the Alert level in accordance with the requirements of Section IV.C.1 to Appendix E of 10 CFR Part 50, as exempted. Classification of emergencies at no higher than an Alert level also maintains consistency with the regulations in 10 CFR 72.32(a)(3), Classification of accidents.

Based on the NRC staffs review of the proposed TMI Station EP and associated EAL scheme, as described above, the NRC staff concludes that planning standard 10 CFR 50.47(b)(4) and requirement of 10 CFR Part 50, Appendix E, Section IV.C.1, as exempted, pertaining to a standard emergency classification and action level scheme, are addressed in an acceptable manner in the TMI Station EP and associated EAL scheme, considering the permanently shut down and defueled status of the facility, and the proposed transfer of all remaining spent fuel from the SFPs to dry cask storage within the onsite ISFSI.

3.3.2 Replacement of the Shift Manager with the ISFSI Shift Supervisor In Section 2.1, On-Shift Positions, the proposed TMI Station EP, Exelon reassigned the following Emergency Director responsibilities from the Shift Manager to the ISFSI Shift Supervisor:

The ISFSI Shift Supervisor will be at TMI-1 ISFSI on a continuous, 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per day basis, and will be the senior management position during off-hours. This position is responsible for monitoring ISFSI conditions and managing the activities at the TMI-1 ISFSI. This position assumes overall command and control of the response as the Emergency Director and is responsible for monitoring conditions and approving all onsite activities.

The non-delegable responsibilities of the ISFSI Shift Supervisor/Emergency Director include the following:

Event classification and emergency declaration, and Authorization of radiation exposure in excess of 10 CFR Part 20 limits.

Key delegable responsibilities of the ISFSI Shift Supervisor/Emergency Director include the following:

Notification of offsite agencies (Federal, State and local);

Management of available station resources; Initiation of assessment and mitigative/corrective actions; Initiation of onsite protective actions; Decision to call for offsite law enforcement, firefighting, or ambulance assistance; Augmentation of the ERO as deemed necessary; Coordination or suspension of security activities; Termination of the emergency condition when appropriate; Performance of initial radiological assessment, and Maintenance of a record of event activities.

Section 15.0, Radiological Emergency Response Training, of the proposed TMI Station EP provides the requirements for emergency preparedness training, and identifies the level and the depth to which individuals are to be trained. The personnel assigned to the ISFSI Shift Supervisor/Emergency Director and Resource Manager positions shall have training conducted on an annual basis such that proficiency is maintained on the topics listed below:

Emergency classification; State and local government agencies, and NRC notifications; ERO activation; Dose rate meter operation;

Radiological release assessment; Emergency exposure control; Protective actions for onsite personnel; ISFSI design-basis accidents and accident assessment, and Review of applicable drill identified deficiencies and human performance concerns.

The NRC staffs evaluation verified the retitled position of ISFSI Shift Supervisor is on-shift at the TMI-1 ISFSI 24-hours a day / 7 days a week and serves as the senior management position during off-hours. This position assumes overall command and control of the event response as the Emergency Director and is responsible for monitoring conditions and approving all onsite activities. The TMI Station EP clearly identifies non-delegable responsibilities, along with other designated tasks, for the ISFSI Shift Supervisor. The NRC staff considers this retitling activity to be an administrative change that will not impact the timing or performance of existing emergency response duties.

Based on the NRC staffs review of the proposed TMI Station EP and associated EAL scheme, as described above, the NRC staff concludes that planning standard 10 CFR 50.47(b)(2),

pertaining to the adequate staffing to provide initial facility accident response, and requirements of 10 CFR Part 50, Appendix E, Section IV.A, as exempted, pertaining to the organization for coping with radiological emergencies is described, including definition of authorities, responsibilities, and duties of individuals assigned to Exelons emergency organization, are addressed in an acceptable manner in the TMI Station EP, considering the permanently shut down and defueled status of the facility, and the proposed transfer of all remaining spent fuel from the SFP to dry cask storage within the onsite ISFSI.

3.3.3 Emergency Response Organization Revision The existing TMI PDEP provides for two ERO augmented positions - a Technical Coordinator and a Radiation Protection Coordinator. The proposed TMI Station EP would replace these positions with two other positions: a Resource Manager, and an individual trained in radiological monitoring and assessment. The Resource Manager will assist in assessing the event and obtaining needed resources, including public information interface. The Resource Manager will be in contact with the Emergency Director within two hours of declaration of an Unusual Event or an Alert classification level. The Resource Manager does not need to physically report to the TMI-1 ISFSI to perform their responsibilities. The Resource Manager augments the Emergency Director by assisting in assessing the emergency condition and coordinating the required resources, including serving as the public information interface. Services provided to the Emergency Director by the Resource Manager can be provided remotely and do not necessitate an onsite response by the Resource Manager. By responding remotely, the actual response time is decreased (as compared to the ERO response required by the PDEP as described above) with no negative impact to services and functional responsibilities provided by the Resource Manager. The Resource Manager's functional responsibilities could be performed in a timely manner either by reporting to the site or performing the function remotely in the specified timeframe.

In addition, Exelon proposes that a minimum of one person trained in radiological monitoring and assessment will report to the TMI-1 ISFSI within four hours of a declared emergency involving radiological consequences.

In its evaluation of the proposed changes to the ERO, the NRC staff considered the accident analysis referenced above, related to the deletion of EALs, either partially or in their entirety, as indicated, as they relate to SFP operation. Specifically, the NRC staff considered the postulated accidents that could occur with all the spent fuel moved into dry cask storage within the onsite ISFSI, which pose a very low risk to public health and safety. The NRC staff notes that Exelon also continues to commit to maintain the appropriate level of augmented response to an emergency, to include an event involving radiological consequences.

In the Statement of Considerations for the Final Rule for Emergency Planning Licensing Requirements for Independent Spent Fuel Storage Facilities and Monitored Retrievable Storage Facilities (MRS) (60 FR 32430; June 22, 1995), the Commission stated, in part:

For there to be a significant environmental impact resulting from an accident involving the dry storage of spent nuclear fuel, a significant amount of the radioactive material contained within a cask must escape its packaging and enter the biosphere. There are two primary factors that protect the public health and safety from this event. The first is the design requirements for the cask that are imposed by regulation.

These general design criteria place an upper bound on the energy a cask can absorb before the fuel is damaged. No credible dynamic events have been identified that could impart such significant amounts of energy to a storage cask after that cask is placed at the ISFSI.

Additionally, there is a second factor which does not rely upon the cask itself but considers the age of the spent fuel and the lack of dispersal mechanisms. There exists no significant dispersal mechanism for the radioactive material contained within a storage cask.

Based on the design limitations, the majority of spent fuel is cooled greater than 5 years. At this age, spent fuel has a heat generation rate that is too low to cause significant particulate dispersal in the unlikely event of a cask confinement boundary failure.

Although the TMI-1 spent fuel analysis has not been able to identify any design-basis accident that would result in a failure of the confinement barrier for the dry storage casks or the irradiated fuel itself, the TMI Station EP nonetheless requires augmentation of one person trained in radiological monitoring and assessment, who will report to the station within four hours of the emergency declaration for an event involving radiological consequences.

The proposed TMI Station EP also provides that additional personnel resources may be directed to report to TMI-1 ISFSI to provide additional support, as needed, to assess radiological conditions, support maintenance and repair activities, develop and implement corrective action plans, and assist with recovery actions. The augmentation personnel are available from TMI staff, Exelon and from various contractors.

Based on the NRC staffs review of the proposed TMI Station EP and associated EAL scheme, as described above, the NRC staff concludes that planning standards 10 CFR 50.47(b)(1) and (b)(2), and the requirements of Section IV.A of Appendix E to 10 CFR Part 50, as exempted, pertaining to timely augmentation of response capabilities and coping with radiological emergencies, are addressed in an acceptable manner in the TMI Station EP, considering the

permanently shut down and defueled status of the facility, and the proposed transfer of all remaining spent fuel from the SFP to dry cask storage within the onsite ISFSI.

4.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20, and changes administrative procedures or requirements. The NRC staff has determined that the amendment involves 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. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding, which was published in the Federal Register on April 20, 2021 (86 FR 20526). Accordingly, the amendment meets the eligibility criteria for categorical exclusions set forth in 10 CFR 51.22(c)(10)(ii). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment.

5.0 STATE CONSULTATION

In accordance with the Commission's regulations, a Commonwealth of Pennsylvania official was notified of the proposed issuance of the amendment on March 9, 2022 (ADAMS Accession No. ML22068A179). On March 10, 2022, the Commonwealth of Pennsylvania official had no comments (ADAMS Accession No. ML22070A120).

6.0 CONCLUSION

Based on review of the proposed TMI Station EP and associated EAL scheme, the NRC staff finds that the proposed changes would continue to meet the applicable planning standards in 10 CFR 50.47(b) and the requirements in Appendix E of 10 CFR Part 50, as exempted. The NRC staff finds continued reasonable assurance that adequate protective measures can and will be taken in the event of a radiological emergency at the TMI facility. In addition, the NRC staff concludes that the TMI Station EP will be consistent with the emergency planning requirements for a specific licensed ISFSI under 10 CFR Part 72. Therefore, the NRC staff concludes that Exelons proposed TMI Station EP and associated EAL scheme in its letter dated March 4, 2021, as supplemented by letter dated August 30, 2021, are acceptable.

The NRC staff has concluded, based on the considerations discussed above, 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 continues to be reasonable assurance that such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

7.0 REFERENCES

1. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Certification of Permanent Cessation of Power Operations for Three Mile Island Nuclear Station, Unit 1, dated June 20, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17171A151).

2. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Certification of Permanent Removal of Fuel from the Reactor Vessel for Three Mile Island Nuclear Station, Unit 1, dated September 26, 2019 (ADAMS Accession No. ML19269E480).

3. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, License Amendment Request - Proposed Changes to the Three Mile Island Emergency Plan for Independent Spent Fuel Storage Installation Only Emergency Plan and Emergency Action Level Scheme, dated March 4, 2021 (ADAMS Accession No. ML21063A446).

4. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Supplement to License Amendment Request - Proposed Changes to the Three Mile Island Emergency Plan for Independent Spent Fuel Storage Installation Only Emergency Plan and Emergency Action Level Scheme, dated August 30, 2021 (ADAMS Accession No. ML21242A259).

5. Letter from U.S. Nuclear Regulatory Commission to Exelon Generation Company, LLC, Three Mile Island Nuclear Station, Units 1 and 2 Exemptions, dated December 1, 2020 (ADAMS Accession No. ML20244A291).

6. U.S. Nuclear Regulatory Commission and Federal Emergency Management Agency, Criteria for Preparation and Evaluation of Radiological Emergency Response Plans and Preparedness in Support of Nuclear Power Plants, NUREG-0654/FEMA-REP-1, Revision1, dated November 1980 (ADAMS Accession No. ML040420012).

7. NSIR/DRP-ISG-2, Emergency Planning Exemption Requests for Decommissioning Nuclear Power Plants, dated May 11, 2015 (ADAMS Accession No. ML14106A057).

8. NUREG-2215, Standard Review Plan for Spent Fuel Dry Storage Systems and Facilities, dated April 2020 (ADAMS Accession No. ML20121A190).

9. Nuclear Energy Institute (NEI) 99-01, Revision 6, Development of Emergency Action Levels for Non-Passive Reactors, dated November 2012 (ADAMS Accession No. ML12326A805).

10. Letter, Mark Thaggard (NRC) to Susan Perkins-Grew (NEI), Technical Evaluation for the Endorsement of NEI 99-01, Revision 6, dated March 28, 2013 (ADAMS Accession No. ML12346A463).

11. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E, dated July 1, 2019 (ADAMS Accession No. ML19182A104).

12. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Supplement to Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E and License Amendment Request for Proposed Changes to the Three Mile Island Emergency Plan for Permanently Defueled Emergency Plan and Emergency Action Level Scheme, dated October 9, 2019 (ADAMS Accession No. ML19282C285).

13. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Response to Request for Additional Information (RAI) Regarding Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR Part 50, Appendix E, dated December 10, 2019 (ADAMS Accession No. ML19344C115).

14. Letter from U.S. Nuclear Regulatory Commission to Exelon Generation Company, LLC, Three Mile Island Nuclear Station, Units 1 and 2 - Issuance of Amendment No. 299, Re: Permanently Defueled Emergency Plan and Emergency Action Level Scheme Changes (EPID L-2019-LLA-0144), dated December 2, 2020 (ADAMS Accession No. ML20261H925).

15. Letter from Exelon Generation Company, LLC to U.S. Nuclear Regulatory Commission, Notification of Three Mile Island Implementation of Permanently Defueled Emergency Plan, dated January 20, 2021 (ADAMS Accession No. ML21020A003).

16. U.S. Environmental Protection Agency, EPA 400-R-92-001, Manual of Protective Action Guides and Protective Actions for Nuclear Incidents, dated October 1991 (Reprinted May 1992).

17. Letter from NAC International to U.S. Nuclear Regulatory Commission, Submission of Final Safety Analysis Report (FSAR), Revision 10, for the MAGNASTOR Storage System, dated January 31, 2020 (ADAMS Accession No. ML19035A242).

Principal Contributor: Jeannette Arce