PLA-8189, Supplement to License Amendment Requesting Revision to Technical Specifications for Reactor Vessel Water Level 3 and Level 8 Allowable Values - PLA-8189
| ML25253A240 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 09/10/2025 |
| From: | Casulli E Susquehanna, Talen Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| PLA-8189 | |
| Download: ML25253A240 (1) | |
Text
Edward Casulli Site Vice President September 10, 2025 Attn: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Susquehanna Nuclear, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3795 Fax 570.542.1504 Edward.Casulli@TalenEnergy.com SUSQUEHANNA STEAM ELECTRIC STATION SUPPLEMENT TO LICENSE AMENDMENT REQUESTING REVISION TO TECHNICAL SPECIFICATIONS FOR REACTOR VESSEL WATER LEVEL 3 AND LEVEL 8 ALLOWABLE VALUES PLA-8189 TALEN~
ENERGY 10 CFR 50.90 Docket No. 50-387 and 50-388
References:
- 1) Susquehanna letter to NRC, "Proposed Amendment to Licenses NPF-14 and NPF-22: Revise Reactor Vessel Water Level 3 and Level 8 Allowable Value (PLA-8144)," dated January 29, 2025 (ADAMS Accession No. ML25029A032).
- 2) NRC letter to Susquehanna, "Regulatory Audit Plan in Support of License Amendment Request to Revise Technical Specifications for Reactor Vessel Water Level 3 and Level 8 Allowable Values (EPID L-2025-LLA-0020),"
dated June 23, 2025 (ADAMS Accession No. ML25162A064).
Pursuant to 10 CFR 50.90, Susquehanna Nuclear, LLC (Susquehanna), submitted, in Reference 1, a request for an amendment to the Technical Specifications (TS) for the Susquehanna Steam Electric Station (SSES), Units 1 and 2, Facility Operating License Numbers NPF-14 and NPF-22. The proposed amendment would modify the Reactor Vessel Water Level-Low, Level 3 Allowable Value (AV) for TS 3.3.1.1, Reactor Protection System (RPS)
Instrumentation, TS 3.3.5.1, Emergency Core Cooling System (ECCS) Instrumentation, TS 3.3.5.2, Reactor Pressure Vessel (RPV) Water Inventory Control Instrumentation, and TS 3.3.6.1, Primary Containment Isolation Instrumentation. The proposed amendment would also modify the Reactor Vessel Water Level - High, Level 8 AV for TS 3.3.5.1, ECCS Instrumentation and TS 3.3.5.3, Reactor Core Isolation Cooling (RCIC) System Instrumentation.
The NRC notified Susquehanna in Reference 2 of the intent to conduct a regulatory audit. The enclosure to this letter provides Susquehanna's responses to requested NRC audit questions.
Document Control Desk PLA-8189 Susquehanna has reviewed the information supporting a finding of No Significant Hazards Consideration and the Environmental Consideration provided to the NRC in Reference 1 and determined the information provided herein does not impact the original conclusions in Reference 1.
There are no new or revised regulatory commitments contained in this submittal.
Should you have any questions regarding this submittal, please contact Ms. Melisa Krick, Manager - Nuclear Regulatory Affairs, at (570) 542-1818.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on E. Casulli
Enclosure:
Responses to Regulatory Audit Questions Copy: NRC Region I Ms. E. Brady, NRC Resident Inspector Mr. R. Guzman, NRC Project Manager Mr. M. Shields, PA DEP/BRP
Enclosure to PLA-8189 Responses to Regulatory Audit Questions
PLA-8189 Enclosure Page 1 of 3 Responses to Regulatory Audit Questions Pursuant to 10 CFR 50.90, Susquehanna Nuclear, LLC (Susquehanna), submitted, in Reference 1, a request for an amendment to the Technical Specifications (TS) for the Susquehanna Steam Electric Station (SSES), Units 1 and 2, Facility Operating License Numbers NPF-14 and NPF-22. The proposed amendment would modify the Reactor Vessel Water Level -
Low, Level 3 Allowable Value (AV) for TS 3.3.1.1, Reactor Protection System (RPS)
Instrumentation, TS 3.3.5.1, Emergency Core Cooling System (ECCS) Instrumentation, TS 3.3.5.2, Reactor Pressure Vessel (RPV) Water Inventory Control Instrumentation, and TS 3.3.6.1, Primary Containment Isolation Instrumentation. The proposed amendment would also modify the Reactor Vessel Water Level - High, Level 8 AV for TS 3.3.5.1, ECCS Instrumentation and TS 3.3.5.3, Reactor Core Isolation Cooling (RCIC) System Instrumentation.
By letter dated June 23, 2025, the NRC notified Susquehanna in Reference 2 of the intent to conduct a regulatory audit. As requested during the audit, the following NRC questions and Susquehannas responses are provided below.
Audit Question 001 (Request 3 in Reference 2)
TS Table 3.3.5.1-1 (Function 3.c) and Table 3.3.5.3-1 (Function 2) state that [Level 8 Reactor Vessel Water Level] trips are also relied upon to trip the feedwater pumps and main turbine in the event of a feedwater controller failure to maximum demand ([Updated Final Safety Analysis Report (UFSAR)] Section 15.1.2, TS 3.3.2.2). The TS and TS Bases indicate different numbers of instrumentation channels for the TS 3.3.5.1 and TS 3.3.5.3 [Level 8] trips versus the TS 3.3.2.2 [Level 8] trips; however, the TS Bases and UFSAR do not appear to contain sufficient detail to confirm or deny that those trip channels utilize different level instruments, reference legs, and/or variable legs.
Provide documentation to confirm the feedwater pump and main turbine trips are unaffected by this proposed change.
Susquehanna Response The Reactor Vessel Water Level 3 and 8 AV setpoint calculations demonstrate that the feedwater pump and main turbine trips are unaffected by this proposed change. Specifically, these calculations list all actuations from the Reactor Vessel Water Level switches which includes the HPCI and RCIC high water level trip. The omission of the feedwater pump and main turbine trips from the calculations confirm they are not actuated by these devices.
Additionally, the Reactor Vessel Water Level switches are manufactured by Barton. The main turbine and feedwater turbine high water level trips are initiated from transmitters manufactured
PLA-8189 Enclosure Page 2 of 3 by Rosemount, demonstrating that there are two different instruments initiating the isolation.
This logic separation is illustrated in piping and instrument diagram M-142, Sheet 1 (Unit 1),
which shows the Rosemount transmitters provide input into the integrated controls system which controls the feed pump and main turbine trips (Reference 4). The Unit 1 drawing is considered representative of both Unit 1 and Unit 2.
Audit Question 002 (Request 4 in Reference 3)
The NRC staff requests the licensee to explain why it uses the drift data from a Unit 2 transmitter for the Unit 1 determinations (e.g., are the units have differing environmental conditions?). How much would process setpoints associated with individual units change if the calculations used a drift data set associated with a transmitter in that designated unit?
Susquehanna Response The two units experience similar environmental conditions. The drift analysis was performed on the Reactor Vessel Water Level switch that resulted in the most conservative result. The design philosophy is to ensure that adequate drift margin is built into the field setpoints so that the AV is not violated. By using a bounding approach, it maintains conservativism in the field setpoints.
It is important to note that the drift value does not factor into the AV calculation. Drift is important in determining the field setpoint to ensure the AV is not violated. The drift of Barton devices can have a wide degree of variance even when experiencing similar environmental conditions. For example, a different Unit 2 switch drift, in the same environment, experienced approximately 58% of the drift for the instrument that was used in the analysis. The variability can be considerable and that is why the most conservative value was chosen.
PLA-8189 Enclosure Page 3 of 3 References
- 1. Susquehanna letter to NRC, Proposed Amendment to Licenses NPF-14 and NPF-22: Revise Reactor Vessel Water Level 3 and Level 8 Allowable Value (PLA-8144), dated January 29, 2025 (ADAMS Accession No. ML25029A032).
- 2. NRC letter to Susquehanna, Regulatory Audit Plan in Support of License Amendment Request to Revise Technical Specifications for Reactor Vessel Water Level 3 and Level 8 Allowable Values (EPID L-2025-LLA-0020), dated June 23, 2025 (ADAMS Accession No. ML25162A064).
- 3. NRC email to Susquehanna, RE: Supplement to Audit Plan for SSES LAR L-2025-LLA-0020, dated July 7, 2025 (ADAMS Accession No. ML25224A060).
- 4. Susquehanna Steam Electric Station - Submittal of Revision 71 to Updated Final Safety Analysis Report and Revision 25 to Fire Protection Review Report, dated October 12, 2023 (ADAMS Accession No. ML23291A105).