ML25076A379
| ML25076A379 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 03/10/2025 |
| From: | Gurjendra Bedi Exelon Generation Co LLC |
| To: | V Sreenivas NRC/NRR/DORL/LPL1 |
| Kim, J | |
| References | |
| Download: ML25076A379 (1) | |
Text
From:
Gurjendra Bedi To:
V Sreenivas Cc:
Gurjendra Bedi; Thomas Scarbrough
Subject:
RE: Ginna Alternative Request VR-04 Clarification Responses Date:
Monday, March 10, 2025 12:50:50 PM Dr. V Thank you. Please enter this email in to ADAMS so that this clarification can be used in SE if needed.
G. S. Bedi
From: Bowers, Steven L: (Constellation Nuclear) <Steven.Bowers@constellation.com>
Sent: Thursday, March 6, 2025 12:44 PM To: V Sreenivas <V.Sreenivas@nrc.gov>
Cc: Hipo Gonzalez <Hipolito.Gonzalez@nrc.gov>; Gurjendra Bedi <Gurjendra.Bedi@nrc.gov>; Para, Wendi E: (Constellation Nuclear) <wendi.para@constellation.com>; Knowles, Justin W:
(Constellation Nuclear) <Justin.Knowles@constellation.com>; Henry, Michael: (Constellation Nuclear) <Michael.Henry@Constellation.com>
Subject:
[External_Sender] Ginna Alternative Request VR-04 Clarification Responses
Good afternoon, Dr. V. Sreenivas:
List below are the responses to your request for Ginna Alternative Request VR-04 Clarifications per email dated February 22, 2025, and the associated follow-up dated email February 24, 2025. Let us know if we can be of further assistance in this matter.
NRC Requested Information: Ginna Alternative Request VR-04 Clarification
NRC Clarification-01
Alternative Request VR-04, Section 4, Reason for Request, states in part:
1.a. RV-203 is a group of one (i.e., the only relief valve in the group). Replacement of RV-203 requires the plant to be shutdown therefore RV-203 is normally replaced with a pre-tested spare every 3 years [48 months] to align with RFOs and meet the ASME OM Code requirement in Mandatory Appendix I, Subparagraph I-1350(a) of 48-months.
Can you please confirm that if Alternative Request VR-04 using only relief valve in the group and ASME Code Case OMN-24, Alternative Requirements for Testing ASME Class 2 and 3 Pressure Relief Valves (For Relief Valves in a Group of One),
at Ginna.
NRC clarification based on email on 02/24/2025: Specifically, clarify if Ginna is using ASME Code Case OMN-24, Alternative Requirements for Testing ASME Class 2 and 3 Pressure Relief Valves (For Relief Valves in a Group of One) for Ginna Alternative Request VR-04.
CEG Response:
OMN-24 has not been implemented at Ginna.
1.b The current Ginna Sixth 10-Year Inservice Testing Program, Attachment 15, Inservice Testing Valve Table, (ML20036C593) indicates on page 23 of 67 that RV-203 has a testing frequency of 10 years. The licensee is requested to discuss the test interval in Alternative Request VR-04 (to replace valve every 3 years) and the test interval specified in the IST Program table of Ginna Sixth IST Program.
CEG Response:
The 10-year interval reported in the IST Program Plan is the maximum interval for the individual valve required by ASME OM Code 2012 Mandatory Appendix I Section I-1350(a). The 3-year requirement is necessary to meet the grouping requirement in the same section, which requires 20% of the group to be tested every 48 months. RV-203 can only be tested during an outage, and since Ginna is on an 18-month outage frequency this results in an effective test frequency of 3 years. The Program Plan documents the maximum interval for the individual valve and a Periodic Maintenance activity is utilized to ensure the grouping requirement is met.
NRC Clarification-02
In Alternative Request VR-04, the licensee proposed an extension of the testing/replacement interval for valve RV-203 no later than the Spring 2026 RFO at Ginna.
Could you able to confirm (1) if you had any issue or repair of this valve since the previous Ginna refueling outage in 2021, and (2) the plan if the RV-203 relief valve does not perform its required function during the requested extension period.
NRC clarification based on email on 02/24/2025: The NRC is looking to understand the system impact if it is assumed the valve does not perform its function during the extension period.
CEG Response:
(1) There have been no issues with the installed valve (serial no. 50998) since the 2021 refueling outage.
(2) RV-203 performs an ACTIVE safety function in the OPEN direction to provide overpressure protection for the Chemical Volume and Control System (CVCS) letdown piping and the Residual Heat Removal (RHR) low head safety injection (LHSI)/shutdown cooling header. The subject letdown piping and RHR/LHSI piping are low pressure Class 2 components which are attached to the Reactor Coolant System (RCS) pressure boundary.
Additionally, since this low pressure CVCS and RHR/LHSI piping penetrates primary containment and is part of the containment pressure boundary, RV-203 also serves to prevent over pressurization of containment penetration piping through penetrations P111 and P112 due to thermal expansion during post-LOCA conditions. If RV-203 fails to open then low pressure CVCS, RHR, and LHSI piping could be pressurized beyond design limits and penetrations P111 and P112 could be subject to thermal over pressurization.
RV-203 performs a PASSIVE safety function in the CLOSED direction to maintain the
integrity of the CVCS, RHR/LHSI, and primary containment pressure boundary, being designated as a containment isolation valve for penetration P112. If RV-203 fails to stay closed then CVCS, RHR, LHSI, and containment integrity could be adversely impacted.
Fluid discharged from RV-203 goes to the Pressurizer Relief Tank (PRT), which has a rupture disk to allow overflow to the containment sump. Consequences of PRT overflow are less severe than consequences of post-loss-of-coolant accident containment flooding, which has been analyzed and found to be acceptable. Additionally, consequences of RV-203 sticking open during a post-loss-of-coolant-accident event are not as severe as the loss of an RHR pump, which has been postulated as a single failure in the Emergency Core Cooling System analysis. This evaluation of leakage is discussed in further detail within UFSAR section 5.4.5.3.2.3, Effect of Stuck Open Relief Valve.
NRC Clarification -03 Alternative Request VR-04, Section 5, Proposed Alternative and Basis for Use, indicates the as-found testing history of the RV-203 relief valve (serial no. 50998) was satisfactory (SAT) in 2009, 2015, and 2018. [Can you] provide any as-found results for any other test dates (such as 2012) during the operating life of the RV-203 relief valve if available.
CEG Response:
Listed below is a history of the valves installed at the RV-203 location. Serial number 50998 was first installed in the plant in 2006. The valve that was removed in 2006 had a SAT As-Found (AF) test result. Since 2006 the only UNSAT As-Found test result for RV-203 was Serial number N75784-00-0001 in 2012 where it lifted at 530 psig with an acceptable setpoint range of 588 - 624 psig.
AF -
Year Serial No.
AF Setpoint 2021 N75784-00-0002 SAT 2018 50998 SAT 2015 50998 SAT 2012 N75784-00-0001 UNSAT 2009 50998 SAT 2006 N75784-00-0001 SAT
Kind Regards, Steven Bowers Steven Bowers, MEng I I License&Reg Affairs Nuclear Utilities Coating Council (NUCC) Advisory Committee 200 Exelon Way, Kennett Square, PA 19348 I Work 267-533-5101 I Mobile 856-340-2116 I Steven.Bowers@Constellation.com
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