ML24165A129
| ML24165A129 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 06/05/2024 |
| From: | Armstrong L Dominion Energy, Dominion Energy Nuclear Connecticut |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 24-181 | |
| Download: ML24165A129 (1) | |
Text
Graphics Department Millstone Power Station Dominion Energy Nuclear Connecticut 314 Rope Ferry Rd., Waterford, CT 06385 860-437-2515 JUNO 5 2024 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNITS 1, 2, 3, AND ISFSI 10 CFR 50.59 ANNUAL CHANGE REPORT FOR 2023 Serial No.
MPS Lic/MPW Docket No.
License Nos.
ANNUAL REGULATORY COMMITMENT CHANGE REPORT FOR 2023 24-181 RO 50-245 50-336 50-423 72-47 DPR-21 DPR-65 NPF-49 Pursuant to the provisions of 10 CFR 50.59(d)(2), the report for changes made to the facility for Millstone Power Station Unit 2 (MPS2) and Unit 3 (MPS3) are submitted via Attachments 1 and 2 respectively for 2023, and Attachment 3 contains the Annual Commitment Change Report for 2023.
There were no changes made to Millstone Power Station Unit 1 (MPS1) or the Independent Spent Fuel Storage Installation (ISFSI).
This letter constitutes the Annual Commitment Change Report consistent with the Millstone Power Station's Regulatory Commitment Management Program.
If you have any questions or require additional information, please contact Mr. Dean E.
Rowe at (860) 444-5292.
Sincerely,
~~~<f Lori Armstrong Director, Nuclear Station Safety and Licensing Attachments: 3 Commitments made in this letter: None
cc:
USNRC, Region I Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023 Page 2 of 2 475 Allendale Road, Suite 102 King of Prussia, PA 19406-1415 P. Longmire NRC Project Manager Millstone Unit 1 U.S. Nuclear Regulatory Commission One White Flint North 1155 Rockville Pike Rockville, MD 20852-2738 L. A. Kauffman Health Physicist-DNMS U. S. Nuclear Regulatory Commission Region I 475 Allendale Road, Suite 102 King of Prussia, PA 19406-1415 R. V. Guzman NRC Project Manager Millstone Units 2 and 3 U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023 10 CFR 50.59 ANNUAL REPORT 2023 MILLSTONE POWER STATION UNIT 2 Millstone Power Station Unit 2 Dominion Energy Nuclear Connecticut, Inc. (DENG)
MPS2 Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023, page 1 of 1 50.59 Evaluation for a Temporary Design Change MP2-22-01135
Title:
MP2-22-01135 Temporary Capacity Downgrade of the Unit 2 Spent Fuel Pool Cask Crane (M2H9)
==
Description:==
The temporary change MP2-22-01135 will install an alternative wire rope on the MP2 Spent Fuel Cask Crane (SFCC) main hoist drum/reeving system. A one-for-one replacement of the wire rope is not currently available, and the alternate will allow the necessary movement of a Spent Resin Cask. The alternate wire rope will reduce the Maximum Critical Lift (MCL) UFSAR stated rating of the crane from 125 tons to 114 tons. Due to the MCL reduction, the change will include administrative controls to prohibit use of the SFCC Main Hoist for movement of loads exceeding 114 tons while this temporary change is in place. A calculation has been performed to demonstrate that the alternate wire rope meets critical design features, including normal operation, broken rope scenarios, two-blocking and load hang-up, and seismic (OBE & SSE) to qualify as single failure proof in accordance with NUREG-0612 and NUREG-0554.
NUREG-0554 and NUREG-0612 requirements ensure that the crane and the interfacing lift points are designed so that a malfunction of a component in the active load path will not result in the loss of the capability of the system to safely retain lifted loads.
The administrative controls to prohibit movement of any load exceeding 114 tons including a loaded spent fuel cask while this temporary change is in place ensures that there is no increase in the frequency of occurrence, or the consequences of any accident or malfunction previously evaluated. The change does not introduce the potential for an accident of a different type or a malfunction with a different result. Nor does the change result in a design basis limit for a fission product barrier being exceeded or altered. The activity does not involve a change in methodology. As such, this evaluation concludes this temporary change can be implemented without prior NRC approval.
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023 10 CFR 50.59 ANNUAL REPORT 2023 MILLSTONE POWER STATION UNIT 3 Millstone Power Station Unit 3 Dominion Energy Nuclear Connecticut, Inc. (DENC)
MPS3 Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023, page 1 of 1 50.59 Evaluation for ETE-NAF-2023-0055 Rev. 0 MP3-UCR-2023-008
Title:
Implementation of the Updated Rod Ejection Dose Consequences Analysis Addenda
==
Description:==
The activity involves changes in elements of the method of evaluation (MOE) for the Rod Ejection (RE) dose consequences AOR related to 1) code version used to model the analysis (RADTRAD-NAI vl.3-pl), 2) incorporating a core radial peaking factor (FAflN) as a core inventory multiplier, and 3) nuclide data (half-lives, branching fractions and dose conversion factors). NEI 96-07 Revision 1 Section 4.3.8 states that licensees can make changes to elements of a methodology without first obtaining a license amendment if the results are essentially the same as, or more conservative than, previous results.
The three changes identified above were evaluated separately in M3ASTREA-04054R3 Revision 1 Addenda 2 and 3. The changes in RADTRAD-NAI code version and nuclide data each resulted in dose consequences that were essentially the same as previous results, which Nuclear Safety Analysis has generally considered dose consequences within roundoff to two significant figures, and / or within +/- 1 % of the previous results. The addition of the radial peaking factor as a multiplier on the core release fraction used to increase the activity available for release is consistent with RG 1.183 and causes a significant increase in dose consequences, i.e., the results were more conservative than previous results, but within the regulatory limits of 1 0CFR 50.67 and RG 1.183. As a result, the changes to the MOE for the RE dose consequences AOR do not result in departure from a method of evaluation described in the SAR.
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023 ANNUAL COMMITMENT CHANGE REPORT FOR 2023 MILLSTONE POWER STATION Millstone Power Station Unit 1, 2, 3, and ISFSI Dominion Energy Nuclear Connecticut, Inc. (DENC)
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023, page 1 of 3 Annual Regulatory Commitment Change Report for 2023 MPS1 No Change MPS2 Commitment Change Evaluation for MP2-21-01173
==
Description:==
The TCB performance is still verified by individual component response time testing which is also trended. The addition of a noise suppression diode increases the component response time but provides electrical noise suppression. The diode suppression response time is surveilled to ensure the Technical Requirements Manual response time requirements are maintained.
This change has nuclear safety implications but is not considered significant to safety based on the justification provided in EC MP 2-21-01.1.73, and the discussion below.
Safety significance for this component (each of eight (8) Reactor Trip Circuit Breakers (TCB)) is based on the ability to perform its intended design function - which is to execute a reactor trip by completing the TCB t rip. The undervoltage trip device performs the "fail-safe" tripping function.
The historical TCB equipment performance/reliability issues relate to failures to trip, and/or failure to execute a trip within the expected response time resulting from degraded equipment performance and improper maintenance. Safety significance therefore is established based on the impact to the MP2 Safety Analysis given the TCB reactor protective function. The overall Technical Requirements Manual (TRM) Table 3.3-2 (Reactor Protective Instrumentation Response Times) response time acceptance criteria are considered the limiting safety metric or constraint, which are not being changed (with individual TCB reliability and performance assured by continued performance of the vendor recommended TCB preventive maintenance (PM) per C MP 780G (GE Type AK-2/ 2A-25 Low Voltage Power Circuit Breaker Maintenance).
The TCB component performance criteria including response time are maintained consistent with the original commitment. However, the addition of response time acceptance criteria for the TCB plus suppression diode configuration is considered a commitment change (to document the configuration change of the TCB control circuit and the response time increase with the TCB installed in the switchgear). Since the suppression diode is not installed on the TCB, the routine PM and as-left response time test adequately demonstrates the equipment performance consistent with the historical
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023, page 2 of 3 commitment intent and the ability to identify degraded equipment performance is unaffected.
The addition of a noise suppression diode provides a safety improvement by assuring continuity and reliability of the RPS design function by maintaining a transient electrical noise environment that does not compromise the performance of sensitive RPS equipment. The aggregate increase in undervoltage trip device (UVD) response time due to the increase coil release time resulting from the addition of a suppression diode is not considered a substantial negative - based on the equipment design, and the margin available following implementation of the engineering change and/or the ability to adjust the bistable trip units to accommodate and off-set the increase in response time resulting from the suppression diode addition.
GE provided initial recommendations for monitoring equipment performance-in GE Service Advice 175 (CPDD) 9.3 (alternatively 175-9.3) and the Service Advice supplement to 175-9.3 (or 175-9.3S).
Per the NRC's response dated June 24, 2002, from Richard B. Ennis to J. A. Price, re Revised Commitment Associated with Generic Letter 83-28, Millstone Nuclear Power Station, Unit No. 2 (TAC No. MB5292), the licensee has latitude to change the regulatory commitment without prior NRC approval provisionally as guided by LI-AA-110.
The NRC Safety Evaluation evaluated the adequacy of the licensee responses for MP2 to Items 4.2.1 and 4.2.2 of Generic Letter (GL) 83-28, "Required Actions Based on Generic Implications of Salem ATWS Events.11 Items 4.2.1 and 4.2.2 of GL 83-28 addressed the actions to be taken by licensees aimed at ensuring that a comprehensive preventative maintenance program and surveillance testing is implemented for RTCBs.
A comprehensive maintenance program and surveillance testing was implemented and is being maintained to assure the TCBs operate reliably and dependably. The component response time adjustment (relaxation) for TCB plus suppression diode is consistent with the vendor recommendations and provides margin for equipment deviations, while maintaining appropriate constraints via compliance with TRM Table 3.3-2 functional unit acceptance criteria. Therefore, the Safety Analysis is not adversely impacted and the relevant TRM response time acceptance criteria remain bounding.
The individual TCB response time acceptance criteria will remain unchanged at (not to exceed) 50 ms and is included as part of breaker preventative maintenance.
The response time acceptance criteria for testing a TCB with diode suppression installed across the UVD coil is established at 130 msec based on the actual measurements and to provide margin for normal equipment variations. This time is greater than the typical response time addition of a diode listed in service advice 175-
Serial No.24-181 10 CFR 50.59 Annual Report &
Annual Regulatory Commitment Change Report 2023, page 3 of 3 9.3S Item# S6. However, it is necessary to capture the full range of breaker response times along with margin for surveillance testing and provide margin for normal equipment variations. Overall RPS TRM response time will not be impacted by this change.
MPS2 & MPS3 Commitment Change Evaluation for 8.5.b fuel dispersal {Form LI-AA-110, Att. 2)
==
Description:==
The original NRC Order EA-02-026 requiring a SFP thermal management program was fully rescinded [Reference 5] because the requirements were incorporated into 10 CFR 50.54 (hh)(2). 10 CFR 50.54 (hh)(2) was subsequently moved to 10 CFR 50.155 (b)(2)
[Reference 3]. The revised mitigation strategy continues to maintain compliance with 10 CFR 50.155. The revised thermal mitigation strategy results in an improvement in nuclear safety by significantly reducing the number of irradiated fuel assembly movements in the SFP while ensuring that the SFP external makeup and external spray can be implemented in a timely manner.
ISFSI No Change