ML23045A045

Regents of the University of California - Issuance of Amendment No. 9 to Renewed Facility Operating License No. R-130 to Amend the Technical Specifications for the University of California - Davis/Mcclellan Nuclear Research Center

ML23045A045
Person / Time
Site:	University of California-Davis
Issue date:	03/02/2023
From:	Geoffrey Wertz NRC/NRR/DANU/UNPL
To:	McClellan Nuclear Research Center
References
EPID L-2023-NFA-0000
Download: ML23045A045 (1)

Text

March 2, 2023 Dr. Prasant Mohapatra Vice Chancellor for Research Department of Computer Science University of California Davis, CA 95616

SUBJECT:

REGENTS OF THE UNIVERSITY OF CALIFORNIA-ISSUANCE OF AMENDMENT NO. 9 TO RENEWED FACILITY OPERATING LICENSE NO. R-130 TO AMEND THE TECHNICAL SPECIFICATIONS FOR THE UNIVERSITY OF CALIFORNIA-DAVIS/MCCLELLAN NUCLEAR RESEARCH CENTER (EPID NO. L-2023-NFA-0000)

Dear Dr. Mohapatra:

The U.S. Nuclear Regulatory Commission (NRC) has issued the enclosed Amendment No. 9 to Renewed Facility Operating License No. R-130 for the University of California-Davis (UCD),

McClellan Nuclear Research Center (MNRC), Training, Research, Isotope, General Atomics research reactor. This amendment consists of changes to the renewed facility operating license and technical specifications (TSs), in response to the application dated February 8, 2023 (Agencywide Documents Access and Management System Accession No. ML23039A207). This amendment revises UCD MNRC TS 3.3, Reactor Coolant Systems, Specification 4.

P. Mohapatra 2 A copy of the NRC staffs safety evaluation is also enclosed. If you have any questions, please contact me at 301-415-0893, or by email at Geoffrey.Wertz@nrc.gov.

Sincerely, Signed by Wertz, Geoffrey on 03/02/23 Geoffrey A. Wertz, Project Manager Non-Power Production and Utilization Facility Licensing Branch Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Docket No. 50-607 License No. R-130

Enclosures:

1. Amendment No. 9 to Renewed Facility Operating License No. R-130

2. Safety Evaluation cc: See next page

University of California-Davis/McClellan Docket No. 50-607 cc:

David Reap, Radiation Safety Officer 5335 Price Avenue, Bldg. 258 McClellan, CA 95652-2504 California Energy Commission 1516 Ninth Street, MS-34 Sacramento, CA 95814 Radiologic Health Branch California Department of Public Health P.O. Box 997414, MS 7610 Sacramento, CA 95899-7414 Test, Research and Training Reactor Newsletter Attention: Ms. Amber Johnson Dept of Materials Science and Engineering University of Maryland 4418 Stadium Drive College Park, MD 20742-2115 Dr. Wesley D. Frey, Reactor Director McClellan Nuclear Research Center University of California, Davis 5335 Price Avenue, Building 258 McClellan, CA 95652-2504

ML23045A045 NRR-058 OFFICE NRR/DANU/UNPL/PM NRR/DANU/UNPL/LA OGC/NLO NAME GWertz NParker STurks DATE 2/15/2023 2/17/2023 3/2/2023 OFFICE NRR/DANU/UNPL/BC NRR/DANU/UNPL/PM NAME JBorromeo GWertz DATE 3/2/2023 3/2/2023 REGENTS OF THE UNIVERSITY OF CALIFORNIA DOCKET NO. 50-607 UNIVERSITY OF CALIFORNIA - DAVIS MCCLELLAN NUCLEAR RESEARCH CENTER AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 9 License No. R-130

1. The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A. The application for an amendment to Renewed Facility Operating License No. R-130, submitted by the Regents of the University of California (the licensee) on February 8, 2023, complies with the standards and requirements of the Atomic Energy Act of 1954 (the Act), as amended, and the Commissions rules and regulations set forth in Title 10 of the Code of Federal Regulations (10 CFR)

Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance that (i) the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) such activities will be conducted in compliance with the regulations of the Commission set forth in 10 CFR Chapter I; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; E. This amendment is issued in accordance with 10 CFR Part 51, Environmental Protection Regulations for Domestic Licensing and Related Regulatory Functions, of the Commission regulations and all applicable requirements have been satisfied; and F. Prior notice of this amendment was not required by 10 CFR 2.105, Notice of proposed action, and publication of a notice for this amendment is not required by 10 CFR 2.106, Notice of issuance.

Enclosure 1

2. Accordingly, the license is amended as described in Attachment 1 to this license amendment and by changes to the Technical Specifications as indicated in Attachment 2. Paragraph 2.C.2 of Renewed Facility Operating License No. R-130 is hereby amended to read as follows:

2. Technical Specifications The Technical Specifications contained in Appendix A, as revised by Amendment No. 9, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of the date of its issuance.

FOR THE NUCLEAR REGULATORY COMMISSION Joshua M. Digitally signed by Joshua M.

Borromeo Borromeo Joshua M. Borromeo, Chief Non-Power Production and Utilization Facility Licensing Branch Division of Advanced Reactors and Non-Power Production and Utilization Facilities Office of Nuclear Reactor Regulation Attachments:

1. Changes to Renewed Facility Operating License No. R-130

2. Changes to Appendix A, Technical Specifications Date of Issuance: March 2, 2023

ATTACHMENT TO LICENSE AMENDMENT NO. 9 TO RENEWED FACILITY OPERATING LICENSE NO. R-130 UNIVERSITY OF CALIFORNIA - DAVIS MCCLELLAN NUCLEAR RESEARCH CENTER DOCKET NO. 50-607 Replace the following page of Renewed Facility Operating License No. R-130 with the attached revised page. The revised page is identified by amendment number and contain a marginal line indicating the area of change.

Renewed Facility Operating License No. R-130 REMOVE INSERT Attachment 1

C. This license shall be deemed to contain and is subject to the conditions specified in 10 CFR Parts 20, 30, 50, 51, 55, 70, and 73 of the Commissions regulations; is subject to all applicable provisions of the Act; and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified below:

1. Maximum Power Level The licensee is authorized to operate the facility at steady-state power levels not in excess of 1,000 kilowatts (thermal) in accordance with the limitations in the Technical Specifications.

2. Technical Specifications The Technical Specifications contained in Appendix A, as revised by Amendment No. 9, are hereby incorporated in their entirety in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3. Physical Security Plan The licensee shall fully implement and maintain in effect all provisions of the Commission-approved physical security plan, including all amendments and revisions made pursuant to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The approved plan, entitled Physical Security Plan for the U.C. Davis/McClellan Nuclear Research Center, dated January 11, 2022, consists of documents withheld from public disclosure pursuant to 10 CFR 73.21.

D. This license is effective as of the date of issuance and shall expire at midnight, 20 years from its date of Issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Andrea D. Veil, Director Office of Nuclear Reactor Regulation

Attachment:

Appendix A, Technical Specifications Date of Issuance: November 21, 2022 Amendment No. 9 March 2, 2023

ATTACHMENT TO LICENSE AMENDMENT NO. 9 TO RENEWED FACILITY OPERATING LICENSE NO. R-130 UNIVERSITY OF CALIFORNIA - DAVIS MCCLELLAN NUCLEAR RESEARCH CENTER DOCKET NO. 50-607 Replace the following page of Appendix A, Technical Specifications, with the attached revised page. The revised page is identified by amendment number and contain marginal lines indicating the areas of change.

Technical Specifications REMOVE INSERT 11 11 Attachment 2

Specification - The reactor shall not be operated unless the systems and instrumentation channels described below are operable, and the information is displayed locally or in the control room.

1. The bulk tank water temperature shall not exceed 45 °C;

2. The conductivity of the tank water shall be less than 5 mhos/cm when averaged over a one month period;

3. The reactor shall not be operated if water level drops below a depth of 19 feet from the top of the fueled region of the core; and

4. The reactor shall not be operated if the radioactivity of the pool water exceeds the limits of 10 CFR 20 Appendix B Table 3 for radioisotopes with half-lives >24 hours except for tritium which shall have a limit of 0.05 µCi/ml.

5. The reactor core reflooding system is considered operable if the local pressure gauge on the system reads 20 psi or above.

Basis -

1. The primary coolant core inlet temperature alarm assures that large power fluctuations will not occur (SAR Chapter 4.6).

2. Maintaining the primary coolant water conductivity below 5 micromhos/cm averaged over a week will minimize the activation of water impurities and also the corrosion of the reactor structure.

3. The minimum height of 19 feet of water above the fueled region of the core guarantees that there is sufficient water for effective cooling of the fuel and that the radiation levels at the top of the reactor tank are within acceptable limits. This height of water is also a bounding condition for the core thermal hydraulic analysis. (SAR Chapter 4).

4. This specification insures that in the event of a large-scale release of primary coolant no effluence limits are exceeded.

5. This system will allow the facility to recover the core with water in the in the case of a complete LOCA in order to reduce potential exposure to the public to below 10 CFR 20 limits.

3.4 This section intentionally left blank 3.5 Ventilation and Confinement System Applicability - This specification applies to the operation of the facility ventilation and the reactor room confinement system.

Objective - The objective is to ensure that the ventilation and confinement system shall be in operation to mitigate the consequences of possible releases of radioactive materials resulting from reactor operations.

11 Amendment No. 9 March 2, 2023

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 9 TO RENEWED FACILITY OPERATING LICENSE NO. R-130 REGENTS OF THE UNIVERSITY OF CALIFORNIA UNIVERSITY OF CALIFORNIA - DAVIS MCCLELLAN NUCLEAR RESEARCH CENTER DOCKET NO. 50-607

1.0 INTRODUCTION

By letter dated February 8, 2023 (Agencywide Documents Access and Management System Accession No. ML23039A207), Regents of the University of California (the licensee) submitted a license amendment request (LAR) to amend its Appendix A, Technical Specifications, to Renewed Facility Operating License No. R-130 for the University of California-Davis (UCD)

McClellan Nuclear Research Center (MNRC). Specifically, the licensee proposes to revise technical specification (TS) 3.3, Reactor Coolant Systems, Specification 4.

2.0 REGULATORY EVALUATION

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the licensees LAR and evaluated the proposed TS changes based on the regulations and guidance in:

Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, Section 50.36, Technical specifications, which provides the requirements for TSs to be included in facility operating licenses, including research reactor licenses. 10 CFR 50.36(c)(2), Limiting conditions for operation, which requires that TSs specify the lowest functional capability or performance levels of equipment required for safe operation of the facility.

Part 20, Standards for Protection Against Radiation, of 10 CFR, which establishes the regulatory requirements for protection against ionizing radiation resulting from activities conducted under licenses issued by the NRC.

Section 51.22, Criterion for categorical exclusion; identification of licensing and regulatory actions eligible for categorical exclusion or otherwise not requiring Enclosure 2

environmental review, of 10 CFR, which identifies licensing, regulatory, and administrative actions eligible for categorical exclusion from the requirement to prepare an environmental assessment or environmental impact statement.

NUREG-1537, Part 1, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors: Format and Content, Chapter 14, Technical Specifications, Appendix 14.1, Format and Content of Technical Specifications for Non-Power Reactors, Section 6.2.4, Audit Function, and Section 6.4, Procedures (ML042430055), which provides guidance to licensees preparing research reactor applications and TSs.

NUREG-1537, Part 2, Guidelines for Preparing and Reviewing Applications for the Licensing of Non-Power Reactors: Standard Review Plan and Acceptance Criteria, Chapter 14, Technical Specification (ML042430048), which provides guidance to the NRC staff for performing reviews of proposed TSs.

3.0 TECHNICAL EVALUATION

3.1 Background

As stated in its LAR, the licensee proposed to add Specification 4, to TS 3.3, during its license renewal, which stated that:

The reactor shall not be operated if the radioactivity of the pool water exceeds the limits of 10 CFR 20 Appendix B Table 3 for radioisotopes with half-lives >24 hours.

In Safety Evaluation Report, Renewal of the Facility Operating License for the University of California-Davis McClellan Nuclear Research Center TRIGA Research Reactor, License No. R-130, Docket No. 50-607 (license renewal safety evaluation report (SER))

(ML22214B831), issued with the renewed facility operating license, the NRC staff reviewed proposed TS 3.3, Specification 4, and found it acceptable. The NRC staff based its finding on the proposed TSs consistency with the guidance in NUREG-1537, Part 1, Chapter 14, Appendix 14.1, Section 3.3, Coolant Systems, item (8), Secondary and Primary Coolant Radioactivity Limits, which states, in part, that TS limiting conditions for operation (LCOs) should limit the radioactivity in the coolant. Prior to the issuance of the renewed facility operating license, the UCD MNRC TSs did not have radioactivity concentration limits for the primary coolant or reactor pool water. TS 3.3, Specification 4, became effective on November 21, 2022, with the issuance of renewed facility operating license.

As stated in its LAR, during the development of the proposed TS 3.3, Specification 4, supporting license renewal, the licensee reviewed the historical values for all non-tritium nuclides having half-lives greater than 24-hours. These nuclides were assayed at the facility via high resolution gamma-ray spectroscopy. For the non-tritium nuclides, the licensee reviewed proposed TS 3.3, Specification 4, concentration limits, and determined that the specification could be satisfied under any operating conditions. For tritium, the licensee stated that the tritium samples were assayed by an independent laboratory.

However, the licensee only reviewed the most recent result provided by the laboratory at that time, which was dated April 4, 2022, and did not review past historical values. Specifically, the tritium concentration level that was provided on April 4, 2022 (see table below),

was 0.00025 microcuries per milliliter (µCi/ml). At that time, the licensee determined that the facility could easily meet the proposed TS 3.3, Specification 4, limit of 0.01 µCi/ml, as provided in 10 CFR Part 20, Appendix B, Table 3, Releases to Sewers. The license stated that it limited its review to only one result because the tritium reactor pool water concentration varied very little over time.

On January 31, 2023, the licensee discovered that tritium concentration level reported by the laboratory was incorrect and was low by a factor of 100. The licensee reviewed historical tritium concentration values in the reactor pool water and determined that the tritium concentration values were approximately 2 1/2 times higher than the limit specified in TS 3.3, Specification 4.

The licensee based its determination that the April 4, 2022, laboratory test result (0.000253 µCi/ml in table 1 below) for the reactor pool water tritium concentration was incorrect by reviewing approximately 10 years of historical tritium concentrations in the reactor pool water.

The licensee indicated that the data shows that MNRCs primary water tritium levels, during the past 10 years of 1 megawatt single-shift operation, were consistent ranging from a maximum of 0.026 µCi/ml to a minimum of 0.017 µCi/ml with an average concentration level of 0.022 µCi/ml. The data provided by the licensee in its LAR is reproduced in table 1, Historical Primary Water Tritium Concentrations, below:

Table 1 - Historical Primary Water Tritium Concentrations MNRC Primary Water Tritium Assay Date Concentration (µCi/ml) 0.0284 10/08/12 0.0257 04/01/13 0.0241 10/07/13 0.0234 04/14/14 0.0224 10/30/14 0.0209 04/06/15 0.0225 10/05/15 0.0223 04/04/16 0.0202 10/17/16 0.0201 04/10/17 0.0206 10/09/17 0.0208 04/26/18 0.0208 10/01/18 0.0166 04/01/19 0.0207 10/07/19 0.0232 04/20/20 0.0243 11/03/20

MNRC Primary Water Tritium Assay Date Concentration (µCi/ml) 0.0257 04/05/21 0.0252 10/04/21 0.000253* 04/04/22 0.0237 10/12/22

• Misreported results by laboratory and used to support of license renewal The licensee stated that after it recognized that the tritium concentration exceeded the LCO limit in TS 3.3, Specification 4, the reactor was shut down, and remains shut down. The licensee also notified the NRC.

On February 6, 2023, a Category 1 public meeting was held between the NRC staff and the licensee to discuss the proposed LAR increasing the current TS tritium concentration limit in the primary coolant system. The public meeting notice and the meeting summary are available at ML23034A053 and ML23045A369, respectively.

As stated in its LAR, the licensee has secured an alternate laboratory at the UCD to perform the tritium analysis for future reactor coolant water samples. The current independent laboratory, that misreported the primary coolant water tritium levels, will continue to be used for approximately one year to ensure that the results of the two laboratories agree before switching to UCD laboratory to perform the tritium analysis.

3.2 Proposed TS 3.3, Specification 4 The proposed TS changes are denoted using bold to indicate the additional text (no text was deleted).

The current TS 3.3, Specification 4, states:

The reactor shall not be operated if the radioactivity of the pool water exceeds the limits of 10 CFR 20 Appendix B Table 3 for radioisotopes with half-lives >24 hours.

The proposed TS 3.3, Specification 4, states:

The reactor shall not be operated if the radioactivity of the pool water exceeds the limits of 10 CFR 20 Appendix B Table 3 for radioisotopes with half-lives >24 hours except for tritium which shall have a limit of 0.05 µCi/ml.

3.3 Evaluation The NRC staff reviewed the proposed changes using the guidance provided in NUREG-1537, Part 1, chapter 14, appendix 14.1, section 3.3, item (8), which states that TS LCOs should limit the radioactivity in the reactor coolant. Appendix B Table 3 of 10 CFR 20 provides the monthly average concentrations limits of radioactive material that can be discharged to the sanitary sewers. As stated in its LAR, MNRC policy does not allow any liquid radioactive waste to be discharged into the sanitary sewers, and the facility has never discharged primary coolant water

into the sewer, nor does the facility plan to do so. As such, the licensee provided two possible scenarios for an inadvertent release of tritium to the environment: (1) a leak of the primary coolant from the reactor tank and (2) a loss-of-coolant accident (LOCA) event.

The NRC staff reviewed the proposed TS change and finds that the licensee does not plan to release any radioactive liquids to any sanitary sewers, including any release of any primary coolant water. Further, the NRC staff reviewed and evaluated the two possible scenarios for inadvertent release of tritium to the environment, identified above. The NRC staffs evaluation of these two scenarios is as follows.

3.3.1 Slow Leak from the Reactor Pool Tank In its LAR, the licensee stated that in the event of a slow leak from the reactor pool tank, primary coolant would leak into the space between the tank wall and the concrete structure (monolith) that provides biological shielding for personnel in surrounding areas (described in SAR section 5.1, Reactor Tank ML20238B984). The monolith forms the structural center and foundation of the facility. As a design feature of the facility, if a tank leak did form, primary water would most likely be discovered in the excavation under Bay 4 (commonly referred to as Bay 5) which is the lowest elevation point at MNRC. This primary cooling water would be recovered in a 6,000-gallon retention tank to avoid being released into the environment. However, unlike many other research reactor tanks, the MNRC reactor tank wall has no penetrations and as such, it is less likely the MNRC reactor will develop a leak. Finally, as part of its routine operations, MNRC staff monitor the addition of water to the reactor tank to track if the tank losses increase beyond typical evaporation losses, which would be indicative of a reactor tank leak.

The NRC staff finds that the licensee has procedures and processes, as described above, to identify and, if needed, recover any primary coolant which may leak from the primary reactor tank. The NRC staff also finds that any water produced as a result of the licensees response to a primary coolant leak would be contained in the retention tank, and not released to the environment. Accordingly, an inadvertent leak from the reactor pool tank would not result in a leak to the environment in excess of regulatory limits.

3.3.2 Loss of Coolant Accident In its LAR, the licensee stated that a complete LOCA event would flood Bay 5 with approximately 7,000 gallons of primary water and uncover the MNRC reactor core. TS 3.3, Specification 5, and emergency plan, provide requirements to reflood the reactor core and Bay 5 with approximately 60,000 gallons of water to re-cover the reactor core and reduce dose (from skyshine) to the public. (Note: the NRC staff evaluation of the UCD LOCA analysis is provided in section 4.2.2, Loss-of-Coolant Accident, of the license renewal SER, available in ADAMS at Accession No. ML22214B831). The licensee indicated that the addition of 60,000 gallons of uncontaminated water would lower the maximum tritium concentration in the primary water of 0.05 µCi/ml to 0.0052 µCi/ml or just over half of the 10 CFR Part 20, Appendix B, Table 3 limit of 0.01 µCi/ml for tritium discharge to the sewer. The licensee indicated that there was no known mechanism for a complete LOCA event at MNRC and this scenario was only provided to demonstrate that even under a highly unlikely event, the proposed changes to TS 3.3, Specification 4, would not result in a discharge in excess of regulatory limits and would not represent an undue risk to public safety or to the environment.

Further, the licensee stated that ground water is monitored at a well approximately 3 miles west of the MNRC facility. This location was selected as the most likely source that any potential tritium released from MNRC could be introduced to the public. This well is monitored and tested for tritium every three months. No tritium has been detected above the minimum detectable concentration (MDC) over the 20 plus years of MNRC operation.

The radioactivity found in this well water and utilized for tritium analysis, is approximately one percent of the Environmental Protection Agency (EPA) drinking water limit of 20,000 pico-curies per liter (pCi/l) tritium (or 0.00002 µCi/ml).

The NRC staff finds that the dilution effect of the LOCA recovery response (i.e., the addition of 60,000 gallons of uncontaminated water) would lower the maximum tritium concentration in the primary water from the proposed TS limit of 0.05 µCi/ml to 0.0052 µCi/ml. This reduction in tritium concentration would ensure that any potential LOCA release would be well below the 10 CFR Part 20, Appendix B, Table 3 limit of 0.01 µCi/ml for tritium discharge to the sewer.

Further, the licensees groundwater monitoring program, described above, helps ensure that any potential ground water contamination would be identified , and any potential LOCA release would not result in a violation of the EPAs ground water drinking limits for tritium.

3.4. Conclusion Based upon its review of the licensees proposed change to TS 3.3, Specification 4, the NRC staff concludes that the revised TS continues to satisfy the LCO requirement on radioactivity in the reactor coolant. Further, although the historical average concentration level of tritium in the reactor pool water is 0.022 µCi/ml, the proposed limit of 0.05 µCi/ml would not result in a discharge in excess of regulatory limits and would afford the licensee a reasonable degree of operational margin whereby it could avoid unnecessary reactor shutdowns if radioactivity in the reactor coolant water should inadvertently rise to a level somewhat below the TS limit.

In addition, the NRC staff concludes that the probability of either a slow leak going undetected or the occurrence of a LOCA, are both highly unlikely events due to the design of the reactor pool tank (i.e., no penetrations and encased in a concrete monolith). Further, the NRC staff concludes that if such events did occur, the leak monitoring (routinely done by the MNRC staff);

and the LOCA response directed by the TS 3.3, Specification 5, along with the MNRC emergency plan to recover the core, will result in either no release of reactor coolant to the environment, or will mitigate any release to a concentration that remains below the 10 CFR Part 20, Appendix B, Table 3 value. For all of the reasons discussed above, the NRC staff concludes that proposed TS 3.3, Specification 4, is acceptable.

4.0 ENVIRONMENTAL CONSIDERATION

Pursuant to 10 CFR 51.22(b), no environmental assessment or environmental impact statement is required for any action within the category of actions listed in 10 CFR 51.22(c), for which the Commission has declared to be a categorical exclusion by finding that the action does not individually or cumulatively have a significant effect on the human environment.

4.1 Proposed Changes to TS 3.3, Specification 4 Section 51.22(c)(9) of 10 CFR, states, in part, that issuance of an amendment that changes a requirement with respect to installation or use of a facility component located within the restricted area, as defined by 10 CFR Part 20, meets the definition of a categorical exclusion, provided that the proposed changes satisfy each of 10 CFR 51.22(c)(9) criteria listed below:

(i) The amendment or exemption involves no significant hazards consideration;

[10 CFR 51.22(c)(9)(i)]

Pursuant to 10 CFR 50.92, Issuance of amendment, paragraph (c), the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility, in accordance with the amendment, would not:

(1) involve a significant increase in the probability or consequences of an accident previously evaluated; or [10 CFR 50.92(c)(1)]

As discussed in section 3 of this safety evaluation, the proposed changes to TS 3.3, Specification 4, would increase the allowed tritium concentration level in the reactor pool water. The current TS limit of 0.01 µCi/ml was a new TS requirement, issued with the license renewal on November 21, 2022. Prior to the issuance of the license renewal TSs, there was no TS limit for radioactivity in the reactor pool water.

The licensee had previously adopted the limits in 10 CFR Part 20, Appendix B, Table 3, based on its incorrect belief that it had historically operated with a monthly average concentration of 0.01 µCi/ml. The licensees review historical data to support this new limit was limited to one data point, that was in error and was low by a factor of 100. The licensees re-review of several years of past reactor pool water tritium radioactivity concentration found that the tritium concentration routinely measured around 0.02 µCi/ml.

Therefore, the reactor pool water tritium radioactivity concentration has not significantly changed over many years of operation and was in excess of the selected limit.

In support of its new proposed TS limit of 0.05 µCi/ml, the licensee evaluated the consequences of a slow leak and a LOCA as the only two credible means for reactor pool water to be released to the environment. The slow leak would not increase the consequences as the leak would be contained in the retention tank, and would not be released to the environment. The new concentration limit would not increase in the consequence of a LOCA as the licensees core recovery plan would be implemented to provide 60,000 gallons of water to flood the Bays and reactor pool tank. The core reflood system, required by TS 3.3, Specification 5, maintains this reflooding capability. The dilution effect of the 60,000 gallons would reduce the tritium concentration to approximately 0.0052 µCi/ml, or about half of the limit in 10 CFR Part 20, Appendix B, Table 3.

(2) create the possibility of a new or different kind of accident from any accident previously evaluated; or [10 CFR 50.92(c)(2)]

As discussed in section 3 of this safety evaluation, the proposed changes to TS 3.3, Specification 4, would increase the allowed tritium concentration in the reactor pool water. A loss of reactor pool water (i.e., leak) or a LOCA are the only two credible means for any tritium to be released from the facility since the UCD does not allow routine radioactive liquid discharges. The proposed changes do not involve any hardware changes or significant

changes to the operation of the facility. Therefore, the NRC staff finds that the proposed changes to TS 3.3, Specification 4, do not create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) involve a significant reduction in a margin of safety. [10 CFR 50.92(c)(3)]

As discussed in section 3 of this safety evaluation, the proposed changes to TS 3.3, Specification 4, would increase the allowed tritium concentration in the reactor pool water. The licensee does not allow routine radioactive liquid discharges.

A slow leak of reactor pool water would drain into the annular space between the reactor pool tank and the monolith. The liquid would drain through a drainpipe, and would be identified and collected by operators, who routinely monitor the drainpipe, before any liquid could be inadvertently discharged from the facility.

A LOCA would result in rapid loss of reactor pool water. However, the licensees core recovery plan would be implemented to provide 60,000 gallons of water to flood the Bays and reactor pool tank. The core reflood system, required by TS 3.3, Specification 5, maintains this reflooding capability. The dilution effect of the 60,000 gallons would reduce the tritium concentration to approximately 0.0052 µCi/ml, or about half of the limit in 10 CFR Part 20, Appendix B, Table 3. Further, both release scenarios, the leak and LOCA, are either monitored or have TS required responses that will limit the tritium concentration that may be released. Also, the nearest well used to provide drinking water is monitored for radioactive effluents, thus ensuring the protection of the public. Therefore, the NRC staff finds that this amendment does not involve a significant reduction in a margin of safety.

Based on the above, the NRC staff concludes that the amendment authorizing the changes to TS 3.3, Specification 4 involves no significant hazards consideration.

(ii) There is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite; and [10 CFR 51.22(c)(9)(ii)]

The proposed changes to TS 3.3, Specification 4 do not result in any significant changes in the type and the amounts of radionuclide effluents released by the facility. The proposed changes allow for an increase in the tritium concentration in the reactor pool water. However, as stated above, the licensee does not allow any routine release of radioactive liquids, and both the slow leak and LOCA scenarios do not result in any releases above the limits in 10 CFR Part 20, Appendix B, Table 3.

(iii) There is no significant increase in individual or cumulative occupational radiation exposure.

[10 CFR 51.22(c)(9)(iii)]

The proposed changes to TS 3.3, Specification 4, do not significantly increase the individual or cumulative occupational radiation exposure. The proposed changes allow for an increase in the tritium concentration in the reactor pool water but do not increase the concentrations in excess of any limits associated

with the release of tritium or any other radioactive effluents. As stated above, the licensee does not allow the routine release of any radioactive liquids, and both the leak and LOCA scenarios do not result in any releases above the limits in 10 CFR Part 20, Appendix B, Table 3.

A slow leak of reactor pool water would drain into the annular space between the reactor pool tank and the monolith. The liquid would drain through a drainpipe, and would be identified and collected by operators, who routinely monitor the drainpipe, before any liquid could be inadvertently discharged from the facility.

A LOCA would result in the rapid loss of reactor pool water. However, the licensees core recovery plan would be implemented to provide 60,000 gallons of water to flood the Bays and reactor pool tank. The core reflood system, required by TS 3.3, Specification 5, maintains this reflooding capability. The dilution effect of the 60,000 gallons would reduce the tritium concentration to approximately 0.0052 µCi/ml, or about half of the limit in 10 CFR Part 20, Appendix B, Table 3.

Further, both release scenarios, the tank leak and the LOCA, are monitored or have TS required responses that will limit the tritium concentration that may be released. Also, any such release would not result in concentrations in excess of EPAs drinking water limit of 20,000 picocuries/liter in the nearest well used to provide drinking water, and that well is monitored for radioactive effluents, thus ensuring the protection of the public.

4.2 Conclusion Based on its review, the NRC staff has determined that the issuance of this amendment changes a requirement with respect to the installation or use of a facility component located within the restricted area under 10 CFR Part 50. The NRC staff also has determined that this amendment involves no significant hazards consideration as well as no significant increase in the amounts, and no significant increase in the types, of any effluents that may be released offsite, and there is no significant increase in individual or cumulative occupational radiation exposure. Therefore, the amendment meets the eligibility criteria for a categorical exclusion set forth in 10 CFR 51.22(c)(9). 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 CONCLUSION

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 is 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.

Principal Contributors: G. Wertz, NRR J. Hudson, NRR L. Tran, NRR Date: March 2, 2023