ML26008A004
| ML26008A004 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  (NPF-069) |
| Issue date: | 02/04/2026 |
| From: | Richard Guzman NRC/NRR/DORL/LPL1 |
| To: | Mudrick C Constellation Energy Generation |
| Guzman R, NRR/DORL/LPL1 | |
| References | |
| EPID L-2025-LLA-0019 | |
| Download: ML26008A004 (0) | |
Text
February 4, 2026 Mr. Christopher H. Mudrick, Sr.
Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer Constellation Nuclear 200 Exelon Way Kennett Square, PA 19348
SUBJECT:
NINE MILE POINT NUCLEAR STATION, UNIT 2 - ISSUANCE OF AMENDMENT NO. 201, REVISION OF SURVEILLANCE REQUIREMENT TO A REDUCED TEST PRESSURE AND CORRESPONDING LEAKAGE RATE FOR MAIN STEAM ISOLATION VALVES (EPID L-2025-LLA-0019)
Dear Mr. Mudrick:
The U.S. Nuclear Regulatory Commission (NRC or the Commission) has issued the enclosed Amendment No. 201 to Renewed Facility Operating License No. NPF-69 for the Nine Mile Point Nuclear Station, Unit 2 (Nine Mile Point 2). The amendment consists of changes to the technical specifications (TSs) in response to your application dated January 29, 2025, as supplemented by letter dated June 9, 2025.
The amendment revises the surveillance requirements (SR) associated with Nine Mile Point 2 TS 3.6.1.3, Primary Containment Isolation Valves (PCIVs). Specifically, the TS is revised to change the main steam isolation valve (MSIV) test pressure value from 40 pounds per square inch gauge (psig) to 25 psig in TS SR 3.6.1.3.12 and adjust the maximum allowable leakage through each MSIV to account for the change in test pressure. The TS change will also adjust the maximum allowable leakage to 39 standard cubic feet per hour when tested at 25 psig.
A copy of the related Safety Evaluation is enclosed. A Notice of Issuance will be included in the Commissions monthly Federal Register notice.
Sincerely,
/RA/
Richard V. Guzman, Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-410
Enclosures:
- 1. Amendment No. 201 to NPF-69
- 2. Safety Evaluation cc: Listserv
NINE MILE POINT NUCLEAR STATION, LLC LONG ISLAND LIGHTING COMPANY CONSTELLATION ENERGY GENERATION, LLC DOCKET NO. 50-410 NINE MILE POINT NUCLEAR STATION, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 201 Renewed License No. NPF-69
- 1.
The U.S. Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment by Constellation Energy Generation, LLC dated January 29, 2025, as supplemented by letter dated June 9, 2025, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commissions rules and regulations set forth in 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 (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations; 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; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
- 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Renewed Facility Operating License No. NPF-69 is hereby amended to read as follows:
2.C.(2) Technical Specifications The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, as revised through Amendment No. 201, are hereby incorporated into this license. Constellation Energy Generation, LLC shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
- 3.
This license amendment is effective as of the date of its issuance and shall be implemented within 60 days.
FOR THE NUCLEAR REGULATORY COMMISSION Undine Shoop, Acting Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Renewed Facility Operating License and Technical Specifications Date of Issuance: February 4, 2026 UNDINE SHOOP Digitally signed by UNDINE SHOOP Date: 2026.02.04 11:50:28 -05'00'
ATTACHMENT TO LICENSE AMENDMENT NO. 201 NINE MILE POINT NUCLEAR STATION, UNIT 2 RENEWED FACILITY OPERATING LICENSE NO. NPF-69 DOCKET NO. 50-410 Replace the following page of the Renewed Facility Operating License with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.
Remove Page Insert Page 4
4 Replace the following page of Appendix A, Technical Specifications, with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the areas of change.
Remove Page Insert Page 3.6.1.3-13 3.6.1.3-13 Renewed License No. NPF-69 Amendment 117 through 200, 201 (1)
Maximum Power Level Constellation Energy Generation, LLC is authorized to operate the facility at reactor core power levels not in excess of 3988 megawatts thermal (100 percent rated power) in accordance with the conditions specified herein.
(2)
Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, as revised through Amendment No. 201 are hereby incorporated into this license. Constellation Energy Generation, LLC shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
(3)
Fuel Storage and Handling (Section 9.1, SSER 4)*
- a. Fuel assemblies, when stored in their shipping containers, shall be stacked no more than three containers high.
- b. When not in the reactor vessel, no more than three fuel assemblies shall be allowed outside of their shipping containers or storage racks in the New Fuel Vault or Spent Fuel Storage Facility.
- c. The above three fuel assemblies shall maintain a minimum edge-to-edge spacing of twelve (12) inches from the shipping container array and approved storage rack locations.
- d. The New Fuel Storage Vault shall have no more than ten fresh fuel assemblies uncovered at any one time.
(4)
Turbine System Maintenance Program (Section 3.5.1.3.10, SER)
The operating licensee shall submit for NRC approval by October 31, 1989, a turbine system maintenance program based on the manufacturers calculations of missile generation probabilities.
(Submitted by NMPC letter dated October 30, 1989 from C.D. Terry and approved by NRC letter dated March 15, 1990 from Robert Martin to Mr. Lawrence Burkhardt, III).
- The parenthetical notation following the title of many license conditions denotes the section of the Safety Evaluation Report (SER) and/or its supplements wherein the license condition is discussed.
PCIVs 3.6.1.3 NMP2 3.6.1.3-13 Amendment 91, 182 SURVEILLANCE REQUIREMENTS (continued)
SURVEILLANCE FREQUENCY SR 3.6.1.3.12 Verify leakage rate through each MSIV is d 39 scfh when tested at t 25 psig.
In accordance with 10 CFR 50 Appendix J Testing Program Plan SR 3.6.1.3.13 Verify combined leakage rate through hydrostatically tested lines that penetrate the primary containment is within limits.
In accordance with 10 CFR 50 Appendix J Testing Program Plan 201
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE REVISION OF SURVEILLANCE REQUIREMENTS ASSOCIATED WITH MAIN STEAM ISOLATION VALVE TEST PRESSURE AMENDMENT NO. 201 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-69 CONSTELLATION ENERGY GENERATION, LLC NINE MILE POINT NUCLEAR STATION, UNIT 2 DOCKET NO. 50-410
1.0 INTRODUCTION
By letter dated January 29, 2025, as supplemented by letter dated June 9, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML25029A181 and ML25155B825, respectively), Constellation Energy Generation, LLC (CEG, the licensee),
requested changes to the Technical Specifications (TS) for Nine Mile Point Nuclear Station (Nine Mile Point), Unit 2. The proposed changes would revise TS 3.6.1.3, Primary Containment Isolation Valves (PCIVs). Specifically, the proposed changes would revise the main steam isolation valve (MSIV) test pressure specified in TS Surveillance Requirement (SR) 3.6.1.3.12 from 40 pounds per square inch gauge (psig) to 25 psig and adjust the maximum allowable leakage through each MSIV to account for the reduced test pressure. Currently, the TS maximum allowable leakage through each MSIV is 50 standard cubic feet per hour (scfh) when tested at 40 psig. Under the proposed changes, the maximum allowable leakage would be revised to 39 scfh when tested at 25 psig.
The supplemental letter dated June 9, 2025, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the U.S. Nuclear Regulatory Commission (NRC or the Commission) staffs original proposed no significant hazards consideration determination as published in the Federal Register on April 15, 2025 (90 FR 15730).
To support the proposed TS changes and pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.12, Specific exemptions, the licensee requested, in Enclosure 1 to the letter dated January 29, 2025, an exemption from a requirements of 10 CFR Part 50, Appendix J, for Nine Mile Point Nuclear Station, Unit 2. The exemption request applies solely to leak rate testing of the MSIVs at the reduced test pressure. The NRC staff addressed the exemption request in a separate correspondence (package, ML26008A002).
2.0 REGULATORY EVALUATION
2.1 System Design and Operation 2.1.1 Main Steam Isolation Valves The four main steam lines (MSLs) that penetrate the drywell are automatically isolated by the MSIVs. Each MSL contains two MSIVs, one located inside primary containment and one located outside primary containment. The MSIVs are considered part of the primary containment boundary. Leakage through the MSIVs represents a potential pathway for fission products to bypass secondary containment and be released to the environment as a ground-level release.
2.1.2 Primary Containment Isolation Valves The function of PCIVs (which include the MSIVs) in combination with other accident mitigation systems is to limit fission product release during and following postulated design basis accidents (DBAs) to within the limits of 10 CFR Section 50.67, Accident source term. Primary containment isolation within the time limits specified for those PCIVs designed to close automatically and within the TS leakage limits ensures that the release of radioactive material to the environment will be consistent with the assumptions used in the analyses for a DBA.
As stated in the Nine Mile Point Nuclear Station, Unit 2, TS Bases for PCIVs, Section B 3.6.1.3, Revision 45, Applicable Safety Analyses, the safety analyses of events requiring primary containment isolation are applicable to Limiting Condition for Operation (LCO) 3.6.1.3. The DBAs that result in a release for which the consequences are mitigated by PCIVs include a loss-of-coolant accident and a main steam line break.
2.2 Description of Proposed Changes The licensee proposed changes to the TSs associated with PCIVs to allow leak testing of the MSIVs at a reduced test pressure of 25 psig. In addition, the proposed reduction in test pressure would require a corresponding adjustment to the maximum allowable leakage through each MSIV to reflect the lower test pressure. Specifically, the licensee proposed the following revision to SR 3.6.1.3.12 (changes shown in bold):
Current SR 3.6.1.3.12 Verify leakage rate through each MSIV is 50 scfh when tested at 40 psig.
In accordance with 10 CFR 50 Appendix J Testing Program Plan Proposed SR 3.6.1.3.12 Verify leakage rate through each MSIV is 39 scfh when tested at 25 psig.
In accordance with 10 CFR 50 Appendix J Testing Program Plan 2.3 Applicable Regulatory Requirements Regulations in 10 CFR 50.54(o) require that primary reactor containments for water-cooled power reactors comply with the requirements of Appendix J to 10 CFR Part 50. Appendix J specifies leakage rate testing requirements and acceptance criteria to verify the leak-tight integrity of the primary reactor containment and the systems and components that penetrate the containment. The purposes of the tests are to assure that:
(1) leakage through the primary reactor containment and systems and components penetrating primary containment shall not exceed allowable leakage rate values assumed in the accident analysis, and (2) periodic surveillance of reactor containment penetrations and isolation valves is performed so that proper maintenance and repairs are made during the service life of the containment, and systems and components penetrating primary containment.
Option B, Paragraph III.B of 10 CFR Part 50, Appendix J, requires licensees to perform Type C pneumatic tests to measure containment isolation valve leakage rates to ensure the integrity of the overall containment system as a barrier to fission product release to reduce the risk from reactor accidents. Appendix J requires leak rate testing of containment isolation valves, including MSIVs at the calculated peak containment internal pressure (Pa) related to the DBA.
Option B, Paragraph II, defines Pa as the calculated peak containment internal pressure related to the DBA loss-of-coolant accident, as specified in the TSs. The licensee is requesting a permanent exemption from Appendix J requirements to allow leak rate testing of the MSIVs at a reduced pressure.
The NRC regulatory requirements related to the content of the TSs are contained in 10 CFR 50.36, Technical specifications. The regulations in 10 CFR 50.36(c)(3), Surveillance requirements, state, in part:
Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the LCO will be met.
2.4 Applicable Regulatory Guidance American National Standards Institute (ANSI)/American Nuclear Society (ANS) 56.8-2002, Containment System Leakage Testing Requirements, provides technical methods and techniques for complying with primary containment leakage rate testing requirements. The NRC endorsed this industry standard in the NRC staffs safety evaluation to Nuclear Energy Institute 94-01, Revision 2-A, Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50, Appendix J.
3.0 TECHNICAL EVALUATION
3.1 10 CFR 50, Appendix J Exemption Request - Testing of MSIVs Appendix J requires leak rate testing of containment isolation valves, including MSIVs at Pa related to the DBA. The tests required by Option B, Paragraph III.B must demonstrate that the sum of the leakage rates at accident pressure of Type B tests, and pathway leakage rates from Type C tests, is less than the performance criterion (La) with margin, as specified in the TS.
Option B, Paragraph II defines La as the maximum allowable leakage rate at pressure Pa as specified in the TSs. The current test pressure for the MSIVs at Nine Mile Point, Unit 2 is 40 psig, in accordance with TS SR 3.6.1.3.12. The MSIVs are oriented in the main steam lines to provide improved sealing in the direction of a postulated accident. The NRC staff notes that the design of the main steam system in most operating boiling-water reactor plants necessitates leak testing the MSIVs by pressurizing the volume between the inboard and outboard valves.
At Nine Mile Point, Unit 2, when inboard MSIVs are tested in the forward (accident) direction with the reactor vessel head removed, installation of plugs at the inside steam nozzle penetrations is required. This process involves draining and pressurizing the volume to Pa. The licensee indicated in the LAR that operational experience has shown these plugs will hold pressure at Pa; however, this configuration does not accurately reflect the leak tightness of the MSIVs. The test volume includes the main steam relief valves, reactor head vent, main steam line drain, and reactor core isolation cooling piping, thereby introducing multiple additional leak paths. The NRC staff agrees that this testing method does not provide an accurate measure of MSIV leak tightness and exposes workers to unnecessary radiological dose due to the installation of plugs inside the steam line nozzle penetrations.
An alternative method at Nine Mile Point, Unit 2 is to simultaneously pressurize the volume between the inboard and outboard MSIVs to Pa. Based on operational experience, testing the inboard MSIVs at full pressure in the reverse direction creates difficulty in achieving proper test conditions due to the valve orientation and does not accurately reflect isolation capability.
Specifically, pressurization at full Pa can lift the disk of the inboard valve, rendering the test meaningless.
Industry experience has shown that testing the inboard and outboard MSIVs simultaneously by pressurizing between the valves at a reduced pressure of 25 psig achieves proper test conditions. Furthermore, when conducting the required leak rate testing at a reduced pressure, the licensee states that the total observed leakage through both valves would be conservatively assigned to the penetration.
The NRC staff acknowledges that testing between the MSIVs is an acceptable technique and provides a conservative evaluation in accordance with ANSI/ANS 56.8-2002. Testing the inboard valve in the reverse direction is conservative because the pressurization force acts opposite to the valves seating force. In addition, due to the orientation of the MSIVs, when the outboard valves are tested in the direction of the accident, the pressurization provides better sealing as it would introduce a force in the direction of the valves seating forces.
Because testing the MSIVs at a reduced pressure allows accurate assessment of valve leak tightness while maintaining a conservative determination of leakage, the NRC staff finds the licensees proposed method of testing the MSIVs at 25 psig to be acceptable.
3.2 Changes to TS 3.6.1.3, Primary Containment Isolation Valves The licensee proposes a revision to SR 3.6.1.3.12 to change the MSIV test pressure from 40 psig to 25 psig, along with a corresponding adjustment to the maximum allowable leakage through each MSIV. The NRC staff evaluation of the reduced test pressure is provided in Section 3.1 above.
The current TS specifies a maximum allowable leakage of 50 scfh when tested at 40 psig.
Using a scaling method, the licensee determined that the equivalent maximum allowable leakage at the proposed test pressure of 25 psig is 39 scfh. In response to a request for additional information (ML25155B825), the licensee provided a detailed explanation of the scaling approach, specifying the methodology used. The licensee applied a simplified flow rate relationship in which leakage is proportional to the square root of the differential pressure to calculate the equivalent leakage limit at the reduced pressure.
The NRC staff reviewed the licensees analysis and found the methodology appropriate, confirming that a maximum leakage rate of 39 scfh at 25 psig is equivalent to 50 scfh at 40 psig.
Because the proposed test pressure (25 psig) and the associated maximum allowable leakage (39 scfh) are equivalent to, and conservative relative to, the current TS requirements (40 psig, 50 scfh), the revised SR provides an accurate and conservative assessment of MSIV performance and condition. Therefore, there are no impacts to the current safety analyses for the DBAs listed in Section 2.1.2 above, and the proposed leakage limit remains bounded by the accident analyses in the current licensing basis.
Therefore, the NRC staff finds the proposed changes to SR 3.6.1.3.12revising both the MSIV test pressure and the maximum allowable leakageacceptable. The revised SR will continue to ensure that the necessary quality of systems and components is maintained that facility operation remains within safety limits, and that the LCO is met, consistent with the requirements of 10 CFR 50.36(c)(3).
3.3 Technical Conclusion The NRC staff has reviewed the licensees proposed change to TS SR 3.6.1.3.12 to reduce the MSIV test pressure. The staff concludes that the proposed acceptance criteria are effective and reliable for determining the operational status of the MSIVs and for verifying that no substantial degradation of the valves has occurred since the last local leak rate test.
Furthermore, the NRC staff finds that performing the leak rate tests at the proposed reduced pressure between the MSIVs provides reasonable assurance that the primary reactor containment remains an essentially leak-tight barrier, capable of limiting the uncontrolled release of radioactive material to the environment.
Based on this evaluation, the NRC staff concludes that the proposed revision to SR 3.6.1.3.12 is acceptable and continues to satisfy the requirements of 10 CFR 50.36(c)(3).
4.0 STATE CONSULTATION
In accordance with the Commissions regulations, the New York State official was notified of the proposed issuance of the amendment on December 11, 2025. On December 22, 2025, the State official confirmed that the State of New York had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance 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 published in the Federal Register on April 15, 2025 (90 FR 15730).
Accordingly, the amendment meets the eligibility criteria for 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 the amendment.
6.0 CONCLUSION
The Commission 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 Commissions 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 Contributor: B. Lee, NRR C. Ashley, NRR Date: February 4, 2026
ML26008A004 NRR-058 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL3/LA NRR/DSS/SCPB/BC NAME RGuzman SLent MValentin DATE 1/7/2026 1/12/2026 09/10/2025 OFFICE NRR/DSS/STSB/BC NRR/DORL/LPL1/BC (A)
NRR/DORL/LPL1/PM NAME SMehta UShoop RGuzman DATE 1/15/2026 1/28/2026 2/4/2026