ML25182A019
| ML25182A019 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/07/2025 |
| From: | Klos L Plant Licensing Branch II |
| To: | Dante Johnson, Sinha S Dominion Energy Virginia, Virginia Electric & Power Co (VEPCO) |
| Klos, J | |
| References | |
| EPID L-2024-LLA-0118 | |
| Download: ML25182A019 (1) | |
Text
From:
John Klos To:
daniel.p.johnson@dominionenergy.com; ext_Shayan_Sinha Cc:
Subject:
Formal RCI issuance due in 14 calendar days.... Surry"s Units 1 and 2, TS change 3.7 (Instrumentation), 3.14 (Circ/Service Water System) Repairs of Service Water System Date:
Monday, July 7, 2025 9:04:52 AM
- Daniel,
The Requests for Confirmation of Information (RCIs) below are being released formally with a 14-day calendar response time, thereby, due by the end of the business day Monday July 21, 2025.
REQUEST FOR CONFIRMATION OF INFORMATION (RCI) VIRGINIA ELECTRIC AND POWER COMPANY DOMINION ENERGY VIRGINIA SURRY POWER STATION UNITS 1 AND 2 PROPOSED LICENSE AMENDMENT REQUEST - TECHNICAL SPECIFICATION CHANGE FOR REPAIR OF THE SERVICE WATER SYSTEM DOCKET NOS. 50-280 AND 50-281 EPID: L-2024-LLA-0118
BACKGROUND
By letter dated September 3, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24248A171, Virginia Electric and Power Company (Dominion Energy Virginia) submitted a request to amend the license and technical specifications for Surry Power Station (Surry), Units 1 and 2, Subsequent Renewed Facility Operating License No. DPR-32 and DPR-37, respectively.
The proposed license amendment request (LAR) would establish the requirements for, and the use of a temporary canal level probe and temporary supply line (jumper) to provide service water (SW) to the component cooling heat exchangers (CCHXs) and facilitate planned maintenance activities (i.e., cleaning, inspection, repair of the existing SW piping).
The licensee proposes to install a carbon fiber-reinforced polymer (CFRP) system on the concrete-encased SW supply piping to the CCHXs. These activities are proposed for a 35-day period during the refueling outage.
REGULATORY BASIS
Surrys Updated Final Safety Analysis Report (UFSAR), Revision 56 (ML24269A218)
Section 1.4, Compliance with Criteria, provides, in part, that Surry was designed to meet the intent of the Generic Design Criteria (GDC) of Appendix A to 10 CFR Part 50.
Specifically;
Section 1.4.1, Quality Standards, Section 1.4.2, Performance Standards, to meet the intent of GDC 1, Quality Standards and Records, aka code compliance supportive of pressure boundary with appropriate quality standards, Section 1.4.2, Performance Standard; Section 1.4.40, Missile Protection; Section 2.2.2.1, Tornadoes; and Section 15.2.3, Tornado Criteria, to meet the intent of GDC 2, Design bases for protection against natural phenomena, and GDC 4, Environmental and dynamic effects design bases,
Section 1.4.67, Fuel and Waster Storage Decay Heat, to meet the intent of GDC 34, Residual Heat Removal, (transfer...decay heat) and GDC 61 Fuel Storage and Handling and Radioactivity control, (fuel storage...residual heat removal capability...)
EMIB RCIs
TECHNICAL ISSUE
A stress analysis of safety-related temporary jumper piping that provides SW to the CCHX is required to demonstrate its structural integrity meeting the applicable codes and standards. Further, the piping system is provided with adequate number and type of supports so that the piping stresses, CCHX nozzle loads, expansion joint movements, and valve accelerations for the applicable load combinations meet the applicable acceptance criteria.
EMIB-RCI-1
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the LAR in accordance with NRR Office Instruction LIC-101, License Amendment Review Procedures (ML19248C539).
Further the NRC staff conducted an audit in accordance with NRR LIC-111, Regulatory Audits, (Revision 2) and this LARs audit plan (ML24309A281).
The NRC staff reviewed; (i) Calculation 15752.02-NPB-002-XE Revision 2: Pipe Stress Analysis of New Configuration for Service Water Temporary Jumper to Component Cooling Water Heat Exchanger, (ii) Nuclear Engineering Standard: DNES-SU-EM-0023 Revision 0: Analysis of Safety Related Piping Surry Power Station-Units 1 and 2, (iii) Temporary SW Piping - Audit Response 3.2, and (iv) the audit response to Question 3.2, 3.3, and 3.4 in the electronic reading room (eroom).
In order to complete its safety evaluation for the safety-related temporary jumper piping, the NRC requests the licensee to confirm the following information on the docket.
Design Inputs from Nuclear Engineering Standard: DNES-SU-EM-0023 Revision 0:
Analysis of Safety Related Piping Surry Power Station-Units 1 and 2:
This document prepared by the licensee provides guidelines for analysis of nuclear piping systems at Surry, which is a compilation of applicable sections of various documents including the design commitments presented in the UFSAR.
This engineering standard document includes equations for evaluating piping stresses. as shown below.
SLP + SDW SH SLP + SDW + B SOBEI + SOBEA 1.2 SH SLP + SDW + B SDBEI + SDBEA 1.8 SH STH f (1.25Sc +0.25SH )
SLP = Longitudinal Pressure Stress SDl = Dead load Stress SOBEI = Operational Basis Earthquake (Inertia) Stress SDBEI = Design Basis earthquake (Inertia) Stress SOBEA = Operational Basis Earthquake Anchor Movement Stress SDBEA = Design Basis Earthquake Anchor Movement Stress
STH = Thermal Expansion Stress f = Stress Range Reduction Factor =1.0 for less than 7000 cycles Sc = Code Allowable Stress at cold temperature
=10960 psi for A672 C65 material
= 9200 psi for A 283 Gr. B material
=15000 psi for A106 Gr B material SH = Code Allowable Stress at design temperature
=10960 psi for A672 C65 material
=9200 psi for A 283 Gr. B material
=15000 psi for A106 Gr B material B = Bump Factor =1.0 for original ARS
= 1.25 for OBEI using SSI-ARS or N-411 ARS
= 1.50 for DBEI using SSI-ARS or N-411 ARS
Review of Stress Analysis Model of Safety-Related Temporary Jumper Piping:
Inputs:
The temporary SW supply jumper piping is a seismic safety-related piping installed from C 96 inch Circulating water (CW) inlet piping (96"-WC-3-10) manway to the inlet piping of CCHX (CCHXs 1-CC-E-1A and 1-CC-E-1B). The model includes flanged spool pieces with butterfly valves at the inlet and the two Heat Exchanger supply connections. A rubber expansion joint (1-SW-1REJ-54) is provided just downstream of the SW manual inlet valve (1-SW-939).
Piping:
30-WS-Pipe: Outside Diameter (OD)=30 wall thickness (t)= 0.375; Material: A672-C55 31 Class 10: OD=31; t=0.5; Material: A283 Gr. B 2-WS-Pipe: OD=2.375; t=0.218; Material: A106 Gr. B The evaluation included as-found reduced wall thicknesses The entire length of 223 feet of temporary jumper piping is located indoors in the basement (elevation 96) of Turbine Building. The piping centerline is at elevation 11-6 with the exception of elevation changes at the CW and CCHX tie-ins where it fits up to the existing valves.
Loadings Considered Dead Weight; Thermal Expansion; and Seismic;
The piping content is water.
Piping and content weight and applicable concentrated weights for valves and flanges were included.
Design Pressure: 25 psig; Normal operating Pressure: 10 to 15 psig
Design Temperature: 320F and 950F Normal Operating Temperature: 320F to 800F; Thermal expansion displacements for heat exchanger nozzle locations were included.
Pressure Thrust Load at CW Bellows Expansion joint was included.
Expansion joint stiffnesses in axial, lateral, torsional, and angular directions were included.
Seismic:
The response spectra input for seismic analysis are the amplified response spectra curves with 2% damping applicable for the Turbine Building basement at elevation 96 in North-South, East-West, and vertical directions. The Response Spectra for seismic analysis for Operational Basis Earthquake (OBE) and Design Basis Earthquake (DBE) are based on Soil Structure Interaction SSI-N411 amplified Response Spectra with bump factors of 1.25 for OBE and 1.5 for DBE.
Applicable Code:
For analysis, the code used is B31.1-1967 Power Piping Code, which meets or exceeds the requirements of USAS B31.1-1955 for Pressure Piping (including code cases N1 through N13).
Stress Intensification Factor (SIF):
SIF of 1.3 was conservatively used for all flanged locations. SIF of 1.3 was applied for socket welded fitting locations.
Piping Supports:
The jumper piping is restrained by 17 supports that include two double struts, seven vertical supports, five vertical/lateral supports, two three way supports, and one vertical E-W snubber:
Review of Stress Analysis Results of Safety-Related Temporary Jumper Piping
The piping stress analysis was performed by the licensee using piping Analysis computer software program, NUPIPE-II Version 3.0.0 using the jumper piping stress model. The piping analysis program NUPIE-II uses finite element stiffness method. The continuous piping is mathematically idealized as an assembly of elastic structural members connecting discrete nodal points consisting of straight runs of pipe, elbows, and valves. Nodal points include locations of piping supports, branch lines, and changes of cross section. Dynamic degrees of freedom corresponding to a cut off frequency of 33 Hz was used.
To conservatively address the as-found wall thickness for 30 piping, the maximum stresses are multiplied by additional factors equivalent SIF values based on thickness.
SLP + SDW SH SLP + SDl + B SOBEI + SOBEA 1.2 SH SLP + SDl + B SDBEI + SDBEA 1.8 SH STH f (1.25Sc +0.25SH )
SLP = Longitudinal Pressure Stress
SDl = Dead load Stress
SOBEI = Operational Basis Earthquake (Inertia) Stress SDBEI = Design Basis earthquake (Inertia) Stress SOBEA = Operational Basis Earthquake Anchor Movement Stress SDBEA = Design Basis Earthquake Anchor Movement Stress STH = Thermal Expansion Stress f = Stress Range Reduction Factor =1.0 for less than 7000 cycles Sc = Code Allowable Stress at cold temperature
= 10960 psi for A672 C65 material
= 9200 psi for A 283 Gr. B material
= 15000 psi for A106 Gr B material SH = Code Allowable Stress at design temperature
= 10960 psi for A672 C65 material
= 9200 psi for A 283 Gr. B material
= 15000 psi for A106 Gr B material B = Bump Factor =1.0 for original ARS
= 1.25 for OBEI using SSI-ARS or N-411 ARS
= 1.50 for DBEI using SSI-ARS or N-411 ARS
The following are the maximum piping stresses with reduced wall thickness for the temporary piping which meet the applicable B 31.1 code acceptance criteria.
SLP + SDW = 3105 psi SH = 10960 psi SLP + SDl + B SOBEI + SOBEA 3550 psi 1.2 SH = 13152 psi SLP + SDl + B SDBEI + SDBEA =
4164 psi 1.8 SH = 10728 psi STH = 6984 psi f (1.25Sc +0.25SH) = 16440 psi
The piping stresses meet the applicable B31.1 code acceptance criteria with significant margin.
The jumper piping is very well supported including for seismic loading. The piping supports are designed for the applied loadings from stress analysis that include dead weight, thermal, and seismic DBE loading.
Seismic Movements:
The stress analysis results show that DBE seismic movements are not significant, approximately 1/16, thus seismic interaction with adjacent equipment is not an issue. The jumper does not pass through any wall penetrations CCHX Nozzle Loads Acceptability
The license evaluated the axial load and bending moments on nozzles from the combination of Dead weight +Thermal+ DBE for acceptability of 1-CC-E-1A: Nozzle:
Faxial = 8053 lb, < Faxial allowable = 144987 lb Mbending = 288236 in-lb < Mbending allowable = 719564 in-lb Interaction of axial and bending
(Faxial / Fallowable) + (Mbending / Mallowable)= 0.456 < 1 1-CC-E-1B: Nozzle:
Faxial = 8690 lb, < Faxial allowable = 144987 lb
Mbending= 381787 in-lb < Mbending allowable = 719564 in-lb Interaction of axial and bending (Faxial / Fallowable) + (Mbending / Mallowable)= 0.591 < 1 The licensee stated thereby that the nozzle loads from temporary SW supply jumper piping stress analysis for component cooling Heat Exchangers 1A and 1B are acceptable.
Valve Accelerations:
The licensee stated that the jumper piping including valve locations is very well restrained.
The valve accelerations for DBE is less than 0.3g compared to minimum required acceleration of 0.6g used for seismic qualification for vertical and horizontal directions.
Expansion Joint Movements:
The license evaluated lateral displacement, axial elongation, axial compression, torsional rotation, and angular rotations from the combination of Dead weight +Thermal+ DBE for acceptability Maximum Lateral Displacement = 0.1398 inch < Allowable =0.5 inch Maximum axial elongation = 0.0840 inch < Allowable = 0.5 inch Maximum axial compression = 0.0840 inch
< Allowable = 1.0 inch Lateral / Axial Interaction = 0.4476 < 1 Maximum torsional rotation = 0.0516 deg < Allowable = 1 deg Maximum Angular rotation =
0.1182 deg < Allowable = 2 deg Torsion / Angular Interaction = 0.1107 < 1
ESEB RCIs
ESEB RCI-1
The NRC staff reviewed calculation CE-1388, titled Pipe Support Analysis of New Configuration for SW Temporary Jumper to Component Cooling Heat Exchanger per DC SU-22-00017.
In order to complete its safety evaluation for the safety-related temporary jumper piping, the NRC requests the licensee to confirm the following information on the docket:
Confirm that the structural evaluation of the maximum calculated axial-bending interaction ratio for the steel pipe supports of the temporary SW jumper is less than 1.0, in accordance with AISC Manual of Steel Construction, Allowable Stress
- Design, 9th Edition, and that compliance of the ratio indicates that strength requirements for combined axial and flexural loading are met.
Confirm that the evaluation of the anchor bolts for the temporary SW jumper support baseplate is designed in accordance with American Concrete Institute or Hilti vendor technical manual and that their calculated stresses are within the code allowable limits.
SCPB RCIs
Heavy Load Background
The NRC staff notes that the Turbine Building overhead crane traverses which exists over permanently installed safety-related components of the SW system. The Turbine Building crane is not designed as a single-failure systems, structures, and components proof and could potentially drop a load and impact permanently installed safety-related SW components that are required to restore the normal SW flow path.
During the LARs audit, the NRC staff requested the licensee to discuss how safety-related portions of the SW system are protected from a heavy load drop coming from the Turbine Building overhead crane.
In Response 2 to SCPB Audit Plan Item/Question 3.5, the licensee indicated that procedure changes and additional procedural controls will be implemented to ensure that the safety-related portions of the SW system are protected from a heavy load drop from the Turbine Building overhead crane.
SCPB RCI-1 Please confirm on the docket that; the heavy loads compensatory measures (as identified in the Response 2 to SCPB Audit Plan Item/Question 3.5 dated April 23, 2025) will include a restricted area for lifted loads equal or greater than 1,600 lbs directly over the permanently installed safety-related SW components that are required to restore the normal SW flow path, unless approved by an Engineering Review with station management concurrence. Engineering Review and approval of lifting activities in the area will ensure that the lifted load, if dropped, will not damage the permanently installed safety-related SW components that are required to restore the normal SW flow path.
SCPB Contingency Action Plan (CAP) Background Please confirm on the docket the CAP details reflected in the following SCPB-RCIs.
SCPB-RCI-2 The Basis for TS 3.8 states, in part, that The allowable value for the containment air partial pressure is presented in TS Figure 3.8-.1 for SW temperatures from 25 to 100°F.
The NRC staff requests confirmation on the docket that the pipe stress calculation 15752.02-NPB-002-XE Revision 2, Pipe Stress Analysis of New Configuration for Service Water Temporary Jumper to Component Cooling Heat Exchanger per DC SU-11-00017, for the Temporary Service Water jumper piping used design pressure and temperature range of 25 psig (10 to 15 psig) normal and 32°F to 80°F, respectively.
SCPB-RCI-3 Audit Information reviewed: Audit Request 3.1 File 3 SU-CALC-MEC-ME-0281.pdf; Calculation ME-0281, Revision 4 Component Cooling Heat Exchanger (CCHX) Operability Curves.
The NRC staff requests confirmation on the docket that CCHX Design and Performance Data for the SW Tube Inlet Temperature equals 95 (+/-1)ºF. (i.e., Table 3-1 and 3-3).
SCPB-RCI-4 Audit Information reviewed: SCPB Question 3.1, File #1 SCPB Question 3.1 Response.pdf.
Please confirm on the docket that; With respect to the temporary safety-related seismic SW continued operation - while two
CCHXs are in service and SW supply temperature is at 80oF - please confirm that a margin of 20oF exists between the assumed design/safety limit heat load and the combined heat load rejected by a) the shutdown Unit 1 and b) that heat load rejected by an operating Unit 2,
That component cooling (CC) would not be required to mitigate a Unit 2 loss of coolant accident during the operation of the temporary safety-related seismic SW jumper, That in the event an 80°F Service Water supply temperature was exceeded while the temporary SW jumper piping is in service, the proposed footnote (*) of TS 3.14.A.2.b becomes limiting. That is: (i) the SW temporary jumper would be declared inoperable; (ii) TS 3.0.1 for Unit 2 will be invoked; and (iii) the CAP activation plan would be activated per LAR Section 3.3 Contingency Action Plan (Reference Dominion Response to a.) of File #1).
SCPB-RCI-5 Audit Information reviewed: Audit Request 3.1.4 File #3 PM-2301 Rev 0 (IndexBuiltDoc-111608).pdf; Calculation PM-2301 Revision 0 Surry Spent Fuel Pool Loss of Cooling Heat-Up Times.
Please confirm on the docket that:
Calculation PM-2301 method and code has been tested and validated by the licensee as documented in PM-1442, Revision 1 HEATUP Version 1 Spent Fuel Pool Heat-up Computer Code to ensure its reliability and accuracy. [
Reference:
Audit Request 3.1.4 File
- 2 Excerpts from PM-1442 Rev1 (IndexBuiltDoc-3960).pdf]
During the 2025 Unit 1 refueling outage spent fuel pool cooling will not be aligned to the temporary SW pipe jumper until at least 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> after shutdown. [
Reference:
Section 8.2 Shutdown Timing of Calculation PM-2301]
Section 11, Precautions and Limitations, of Calculation PM-2301 will be limiting for the alignment of the spent fuel pool to the temporary SW pipe jumper.
After alignment of the temporary SW pipe jumper to the spent fuel pool and in the event of a Spent Fuel Pool (SFP) loss of cooling, the Surry operators will have at least 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> (14.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> per Calculation PM-2301) to restore proper alignment and regain cooling before the SFP temperature limit is exceeded.
NPHP Background The NRC staff RCI regarding the licensees CAP concerning assurance of adequate structural integrity of the partially-installed CFRP composite in the SW pipe in the event of jumper failure that requires flow to be restored to the CCHX through the SW pipe.
NPHP-1 Based on the review of documents titled as Contingency Action Plan Response 3.1, Report 241103-R-01 Revision A, Report 241103-R-01 Revision 0, Supplement to Report 241103-R-01, and NPHP Question 3.1.5, 3.1.6 Response, the NRC staff requests the licensee to confirm on the docket the CAP details about the CFRP (i.e., processes taken during installation to restore flow in the partially-installed CFRP SW pipe) in the following paragraphs.
Please confirm on the docket that;
During the fall 2025 Unit 1 refueling outage, the licensee will not begin active installation of CFRP composite on the SW pipe until all the fuel has been fully offloaded and moved to the SFP.
NPHP-2
In its assessment, the licensee identified a minimum window of time where, if cooling water supply to the SFP via the jumper was interrupted, flow is needed to be restored to the CCHX through the installed CFRP SW pipe to maintain the SFP temperature below 200oF.
This time window is referred to as the Emergency Period and was determined to be 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
Please confirm on the docket that; During the 12-hour Emergency Period, the final hour is used to install any remaining valves and flanges to close the pipeline and restore flow to the SW pipe. This leaves 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />, referred to as 11-hour Action Period, to prepare the interior of the partially-installed CFRP SW pipe to restore flow.
NPHP-3 Please confirm on the docket that; During the 11-hour Action Period, all active CFRP installation will stop, any epoxy (i.e., the installed primer, installed fiber-reinforced fabrics, and/or installed topcoat) that has not reached the tack-free stage will be removed, and the supplemental heat of at least 100oF for duration of 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> or 110oF for duration of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> will be introduced to the entire length of the partially-installed CFRP composite in the pipe to ensure the epoxy has achieved the 85% degree-of-cure (DOC). The licensee would make every effort to ensure that the 85% DOC is achieved for any epoxy inside the pipe so that the epoxy will not be dislodged from the pipe due to hydraulic-related loading and become foreign material within the line once the cooling water is introduced and the pipe is returned to service under the CAP.
NPHP-4 Please confirm on the docket that; The ultimate heat sink limit for the Surry, Unit 1, SW system is 100oF.
NPHP-5 Please confirm on the docket that; During the 11-hour Action Period, the licensee will monitor the temperature exposure of the epoxy in the SW pipe by placing temperature sensors with data logging capability to record the curing temperature. During the 11-hour Action Period, the interior pipe temperature is elevated to at least 100oF for duration of 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> or 110oF for duration of 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> to ensure adequate DOC for epoxy is achieved under CAP.
NPHP-6 Please confirm on the docket that; The licensee will verify the DOC by performing personnel-entry inspections and taking Shore D hardness measurements on the surface of cured partially-installed CFRP composite. Shore D measurements greater than 60 coupled with visual examination and the temperature history recorded by temperature loggers in the line will allow for determination that the partially-installed CFRP composite has reached a cure level of 85% DOC beyond which it will not be dislodged from the SW pipe and will not become risk of foreign material (loose
parts) once flow is restored in the line under the CAP.
NPHP-7 Please confirm on the docket that; The partially-installed CFRP composite needs to be bonded/anchored to bare metal substrate at all terminal ends to ensure that the CFRP would not dislodge due to hydraulic-related loading if flow is restored to the SW pipe under CAP. The layer not bonded/anchored to the terminal end bare metal substrate at all ends will be removed prior to restoring the flow in the line under CAP.
Thanks in advance,
John Klos DORL Mcguire, Surry Licensing Project Manager U.S. NRC, Office of Nuclear Reactor Regulation (NRR),
Division of Operating Reactor Licensing (DORL),
NRC/NRR/DORL/LPL2-1, MS O8B01, O8B03 Washington, DC 20555-0001 301.415.5136, John.Klos@NRC.gov