ML25108A105
| ML25108A105 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/21/2025 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Tennessee Valley Authority |
| Green K, NRR/DORL/LPLII-2 | |
| Shared Package | |
| ML25108A108 | List: |
| References | |
| EPID L-2025-LRM-0031 | |
| Download: ML25108A105 (1) | |
Text
April 21, 2025 LICENSEE:
Tennessee Valley Authority FACILITY:
Sequoyah Nuclear Plant, Units 1 and 2
SUBJECT:
SUMMARY
OF APRIL 16, 2025, PUBLIC MEETING WITH TENNESSEE VALLEY AUTHORITY TO DISCUSS A POTENTIAL EXEMPTION REQUEST REGARDING THE USE OF POTASSIUM HYDROXIDE FOR PH CONTROL (EPID L-2025-LRM-0031)
On April 16, 2025, the U.S. Nuclear Regulatory Commission (NRC) staff held a public meeting via teleconference with representatives of the Tennessee Valley Authority (TVA) and its consultant, the Electric Power Research Institute (EPRI), to discuss a potential exemption request for Sequoyah Nuclear Plant (Sequoyah), Units 1 and 2. The meeting notice and agenda for this meeting, dated March 17, 2025, are available at Agencywide Documents Access and Management System (ADAMS) Accession No. ML25094A078. The licensees slides for the meeting are available at (ML25106A052). A list of the meeting attendees is enclosed.
TVA stated that it is considering the use of potassium hydroxide (KOH) in the Sequoyah reactors to control pH of reactor coolant system in lieu of the lithium hydroxide (LiOH) that is currently used. The impetus for the change to KOH is a desire to diversify the methods of reactor coolant chemistry control in response to global supply chain issues involving enriched LiOH.
In order to use KOH as a chemistry control additive in the reactor coolant system, TVA determined that it would need to revise the Sequoyah Offsite Dose Calculation Manual (ODCM) to account for the radionuclides associated with KOH that are not part of Sequoyahs licensing basis, namely chlorine, potassium, and argon. Additionally, radionuclides for these three elements are not included in the NRCs regulations and guidance pertaining to the demonstration that public doses from radioactive effluents are as low as reasonably achievable.
As such, TVA stated that it believes it would need to request a permanent exemption from certain requirements of Title 10 of the Code of Federal Regulations (CFR) Part 20, Standards for Protection Against Radiation, of 10 CFR Part 50, Appendix I, Numerical Guides for Design Objectives and Limiting Conditions for Operation to Meet the Criterion As Low as is Reasonably Achievable for Radioactive Material in Light-Water-Cooled Nuclear Power Reactor Effluents, of 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, and 40 CFR 190, Environmental Radiation Protection Standards for Nuclear Power Operations, which is an Environmental Protection Agency (EPA) regulation, to support the needed revision to the ODCM. The regulation at 40 CFR 190, which is referenced in the 10 CFR 20.1301(e), provides the annual dose limits for members of the public that result from planned discharges of radioactive materials to the general environment and direct radiation from uranium fuel cycle operations.
Regarding 40 CFR 190, TVA noted that the Federal Register notice for the final rule, Regulatory Guide 1.21, and NUREG-0543 all acknowledge that compliance with the NRCs regulations in 10 CFR Part 50, Appendix I, are generally adequate for demonstrating compliance with 40 CFR 190. The NRC staff communicated that an exemption from 40 CFR 190 may not be needed since TVA is not requesting a change to the dose limits, and if TVAs application would provide a basis from which NRC staff could reasonably conclude that the resultant doses from effluents, including the contribution of the KOH-related radionuclides, will remain below the dose limits. The staff questioned TVA whether it thought it needed an exemption from 40 CFR 190, and if so, when would that request be made of the EPA. TVA replied that it heard the NRC staffs explanation and would consider the information when making its final decision about the exemption request.
TVA noted that Sequoyah, Units 1 and 2, Technical Specifications (TSs) 5.5.1, Offsite Dose Calculation Manual (ODCM), and 5.5.3, Radioactive Effluent Controls Program, reference compliance with the regulations in 10 CFR Part 20, 10 CFR Part 50, Appendix I, and 40 CFR 190; however, it did not believe that the proposed exemption would necessitate any changes to these TSs.
TVA noted that several SECYs discuss recommendations for NRC staff to consider that would allow the use of later International Commission on Radiological Protection (ICRP) standards.
TVA noted that in SECY-01-0148, Processes for Revision of 10 CFR Part 20 Regarding Adoption of ICRP Recommendations on Occupational Dose Limits and Dosimetric Models and Parameters, the NRC stated that some licensees had requested exemptions from 10 CFR Part 20 that allowed them to use later ICRP standards. TVA stated that this SECY is the basis for its approach to request an exemption. TVA also noted that in SECY-99-077, To Request Commission Approval to Grant Exemptions from Portions of 10 CFR Part 20, the NRC staff recommended approval of an exemption that would allow OSRAM, a materials licensee, to use a later ICRP standard.
TVA stated that its proposed permanent exemption request would be to allow Sequoyah, Units 1 and 2, to use ICRPs 72, 119, 144, and 151, and Federal Guidance Reports 12 and 15 to determine the dose coefficients for only radionuclides of chlorine, potassium, and argon, for the purpose of evaluating compliance with relevant requirements of 10 CFR Part 20, 10 CFR Part 50, Appendix I, and 40 CFR 190. The NRC staff emphasized that the NRC cannot grant an exemption from the requirements of 40 CFR 190, and that such request, if needed, should be made of the EPA.
The NRC staff asked if TVA had considered requesting an amendment to the TSs in lieu of asking for a permanent exemption and explained that one approach that TVA could take would be to request changes to TS 5.5.3.d, h, and i, to list the radionuclides that are excepted, e.g.,
potassium, chlorine, and argon. TVA stated that it had not deeply considered changing its TSs since the approach taken by other licensees who wanted to use a later ICRP standard had been to request an exemption. The NRC staff noted that dose contribution from a few radionuclides calculated using one methodology could not easily be added to the dose contribution from the remainder of the radionuclides using a different methodology. The NRC staff suggested that another approach could be to calculate the dose conversion factors for all radionuclides using the later ICRP standards, or to calculate the dose conversion factors for the new radionuclides using the older methods. TVA asked the NRC staff if it were to submit a license amendment request would the staff be able to support TVAs requested approval timeframe. The NRC staff said that it likely would not be able to do so due to the noticing requirements for the no significant hazards consideration and opportunity for hearing unless TVA could show that it meets the standard for an emergency or exigent amendment request, which would likely not be the case for this request. The NRC staff also stated that it still needs to determine whether an environmental assessment would be necessary.
Regarding the new radionuclides, the NRC staff asked if TVA had determined if any of them would be considered principal radionuclides, i.e., will contribute greater than 1 percent of the 10 CFR Part 50, Appendix I, design objective dose when all radionuclides in the type of effluent are considered (Regulatory Guide 1.21). A representative from EPRI stated that it does not anticipate that any of the new radionuclides will be principal radionuclides.
The NRC staff noted that the doses discussed during the meeting were to the public so it asked if TVA believed there would be an occupational dose concern. An EPRI representative stated that it does not anticipate any occupational dose concerns.
The NRC staff inquired about potassium-40 (K-40) and how TVA would distinguish between a dose from naturally occurring K-40 and K-40 from an airborne event at the plant. TVA stated that it would have to take the question back to its radiation protection staff for an answer. The NRC staff also asked how TVA plans to distinguish between the K-40 from the plant and naturally occurring K-40 in its environmental monitoring program. TVA stated that its radioactive effluents contractor has considered this and included information in its data library. Additionally, the staff questioned TVA about how it plans to assess the food chain in Regulatory Guide 1.109, Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I, since it does not consider K40 in the transference to milk. A representative from EPRI stated that it has been considering this and have developed transfer coefficients for K-40.
The NRC staff inquired if any changes would be needed to the plants pollution discharge elimination system permit. TVA stated that it is looking into this matter.
TVA plans to submit the request within the next 60 days and request approval by August 31, 2025.
No regulatory decisions were made at this meeting.
No comments or public meeting feedback forms were received.
Please direct any inquiries to me at 301-415-1627 or Kimberly.Green@nrc.gov.
/RA/
Kimberly J. Green, Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328
Enclosure:
List of Attendees cc: Listserv
Enclosure LIST OF ATTENDEES APRIL 16, 2025, PUBLIC MEETING WITH TENNESSEE VALLEY AUTHORITY POTENTIAL EXEMPTION REQUEST REGARDING USE OF POTASSIUM HYDROXIDE FOR PH CONTROL SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 Name Organization Kim Green U.S. Nuclear Regulatory Commission (NRC)
Kevin Hsueh NRC Bob Pascarelli NRC Steve Bloom NRC David Garmon NRC Bill Rautzen NRC Tim Barvitskie NRC Reena Boruk NRC Ed Miller NRC Sean Meighan NRC Julie Ezell NRC Corban Ryan NRC Adam Nielsen NRC Natasha Childs NRC Jesse Baron Tennessee Valley Authority (TVA)
Karina Nigmatullina TVA Amber Aboulfaida TVA Andy Taylor TVA Rick Medina TVA Andy McNeil TVA Kyle Cothran TVA Tony Cross TVA Will Troxler TVA Amy Stubblefield TVA David Perkins Electric Power Research Institute (EPRI)
Keith Fruzzetti EPRI Michelle Mura EPRI Micheal Smith Nuclear Energy Institute (NEI)
Jana Bergman Curtiss-Wright Sofia Bouhrizi
Électricité de France (EDF)
ML25108A108 (Package)
ML25106A052 (Slides)
ML25094A078 (Meeting Notice)
ML25108A105 (Meeting Summary)
NRC-001 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LAiT NRR/DORL/LPL2-2/BC NRR/DORL/LPL2-2/PM NAME KGreen CAdams (SL)
DWrona KGreen DATE 4/18/2025 4/21/2025 4/21/2025 4/21/2025