ML25065A267
| ML25065A267 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/06/2025 |
| From: | Spina J Arizona Public Service Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 102-08911-JLS/MDD | |
| Download: ML25065A267 (1) | |
Text
10 CFR 50.55a A member of the STARS Alliance LLC Callaway
- Diablo Canyon
- Palo Verde
- Wolf Creek 102-08911-JLS/MDD 0DUFK 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Palo Verde Nuclear Generating Station Units 1, 2, and 3 Docket Nos. STN 50-528, 50-529, and 50-530 Renewed Operating License Nos. NPF-41, NPF-51, NPF-74 Response to Request for Additional Information - Valve Relief Request (VRR) - 02 By letter dated October 22, 2024 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML24296B214), Arizona Public Service Company (APS or the licensee) requested Nuclear Regulatory Commission (NRC) staff approval of Valve Relief Request (VRR) - 02 for an alternative test frequency of certain valves; specifically, to be tested once per refueling cycle in lieu of the quarterly exercise required by paragraph ISTC-3510 of the American Society of Mechanical Engineers (ASME), Operations and Maintenance of Nuclear Power Plants (OM) Code, 2012.
Pursuant to 10 CFR 50.55a(z)(1), OLFHQVHHVPD\\UHTXHVWDXWKRUL]DWLRQRIDSURSRVHG
DOWHUQDWLYHWRWKHUHJXODWRU\\UHTXLUHPHQWVLIWKHSURSRVHGDOWHUQDWLYHLVGHPRQVWUDWHGWR
SURYLGHDQDFFHSWDEOHOHYHORITXDOLW\\DQGVDIHW\\On January 30, 2025, a public meeting was held between the NRC staff and APS representatives to discuss VRR-02 and VRR-03. A summary of this meeting was documented (ADAMS Accession No. ML25031A329).
On February 10, 2025 (ADAMS Accession No. ML25041A286), the NRC staff provided a Request for Additional Information (RAI) to support their review of the requested relief. The Enclosure to this letter provides the APS response to the NRC RAI. No new commitments are being made to the NRC by this letter.
Should you need further information regarding this submittal, please contact Michael D.
DiLorenzo, Department Leader Nuclear Regulatory Affairs - Licensing at (623) 393-3495.
Sincerely, JLS/MDD/cr
Enclosure:
Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2, and 3 - Response to Request for Additional Information - Valve Relief Request (VRR) - 02 cc:
J. D. Monninger NRC Region IV Regional Administrator W. T. Orders NRC NRR Project Manager for PVNGS N. Cuevas NRC Resident Inspector for PVNGS Jennifer L. Spina Vice President Nuclear Regulatory
& Oversight Palo Verde Nuclear Generating Station P.O. Box 52034 Phoenix, AZ 85072 Mail Station 7602 Tel: 623.393.4621 Spina, Jennifer (Z08962)
Digitally signed by Spina, Jennifer (Z08962)
Date: 2025.03.06 16:54:27 -07'00'
Enclosure Palo Verde Nuclear Generating Station Units 1, 2, and 3 Response to Request for Additional Information Valve Relief Request (VRR) - 02
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
Introduction By letter dated October 22, 2024 (Agencywide Documents and Access Management System (ADAMS) Accession No. ML24296B214), Arizona Public Service Company (APS or the licensee) requested Nuclear Regulatory Commission (NRC) staff approval of Valve Relief Request (VRR) - 02 for an alternative test frequency of certain valves; specifically, to be tested once per refueling cycle in lieu of the quarterly exercise required by paragraph ISTC-3510 of the American Society of Mechanical Engineers (ASME), Operations and Maintenance of Nuclear Power Plants (OM) Code, 2012.
Pursuant to 10 CFR 50.55a(z)(1), OLFHQVHHVPD\\UHTXHVWDXWKRUL]DWLRQRIDSURSRVHG
DOWHUQDWLYHWRWKHUHJXODWRU\\UHTXLUHPHQWVLIWKHSURSRVHGDOWHUQDWLYHLVGHPRQVWUDWHGWR
SURYLGHDQDFFHSWDEOHOHYHORITXDOLW\\DQGVDIHW\\ On January 30, 2025, a public meeting was held between the NRC staff and APS representatives to discuss VRR-02 and VRR-03. A summary of this meeting was documented (ADAMS Accession No. ML25031A329).
On February 10, 2025 (ADAMS Accession No. ML25041A286), the NRC staff provided a Request for Additional Information (RAI) to support their review of the requested relief.
This Enclosure provides the APS response to the NRC RAI. The NRC request for additional information (RAI) is stated first followed by the APS response.
NRC RAIs and APS Responses Question 1
RAI-1
Request The licensee is requested to describe the administrative controls (such as the shift turnover process or other operational control procedure) that will be implemented for each valve within the scope of Alternative Request VRR-02 when placed in its non-safety position (particularly beyond a single reactor operator shift period) to ensure that the valve is returned to its safety position following the plant activity.
APS Response The Palo Verde Nuclear Generation Station (PVNGS) normal operating procedures and shift turnover process ensure VRR-02 valves are returned to their safety position following plant activities. VRR-02 valves are controlled with normal operating procedures (NOPs) as shown in Table 1. These procedures are used to open and close the valves for plant activities during the operating cycle. NOPs are written to ensure VRR-02 valves are returned to the close position, as described in Procedure 40DP-9OP09, System Status Control. It states:
NOPs are formatted such that a standard section establishes a normal configuration wherein normal is the Full Power, Mode 1 system line-up. For each section that places a system in other than a normal configuration, a subsequent section exists to restore the normal configuration.
For example, Procedure 40OP-9CP01, Containment Purge System, is used to open and close valves CPAUV0004B and CPBUV0005B for containment venting. Specifically:
Section 6.2, Venting Containment, opens the valves to start the venting process.
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
Section 6.6, Stopping Containment Vent, closes the valves to end the venting process.
When plant activities take longer than one reactor operator shift, operators use the shift turnover process to communicate valve status to the on-coming shift crew. Procedure 40DP-9OP33, Shift Turnover, drives this process with position-specific checklists, person-to-person communication, and documentation. These ensure the on-coming control room staff understand the status of plant equipment. The process requires operators to review the control board indications, discuss plant activities controlled by NOPs, and explain the reason for any valve out of its normal position. VRR-02 valves have control room indications and are included in this review.
Normal operating procedures and the shift turnover process are the administrative controls that ensure each valve in VRR-02 is returned to its normally closed safety position following plant activities.
Question 2
RAI-2
Request As the ASME OM Code quarterly inservice test will not be performed for the valves within the scope of Alternative Request VRR-02, the licensee is requested to describe its plans to assess the operational readiness of each valve when moved to its non-safety position and then returned to its safety position, such as by monitoring stroke performance, any abnormal or erratic operation, and successful full closure to avoid seat leakage.
APS Response PVNGS operators will assess the operational readiness of each valve in VRR-02 by adhering to station requirements to monitor stroke performance, look for abnormal or erratic action, and verify successful closure. The stations procedures, polices, and operational culture demand vigilance and verification each time a piece of equipment operates. PVNGS standards apply to the opening and closing strokes of the stations safety-related valves, regardless of test frequency. The standard will continue to apply to the valves in VRR-02, consistent with elements of ASME OM-2012 that require recording any abnormality or erratic action. Seat leakage will continue to be monitored per seat leakage testing requirements in ASME OM-2012.
Operating procedures that stroke VRR-02 valves are performed in compliance with PVNGS procedures on Conduct of Operations (40DP-9OP02), Procedure and Work Instruction Use and Adherence (01DP-0AP09), and the Condition Reporting Process (01DP-0AP12). These procedures require:
Using established procedures for all plant manipulations (Procedure 40DP-9OP02).
Reading each procedure step and understandLQJ the expected plant response beforetaking action (Procedure 01DP-0AP09).
Observing and verifying the expected response after each action (Procedure 01DP-0AP09)
Documenting in a condition report (and reporting to on-shift management) any
abnormal or erratic action that would challenge full closure of a valve. (Procedure
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
The Condition Reporting Process procedure (01DP-0AP12) ensures valve performance deviations are incorporated into the corrective action program. The Operations Department Practices guidance (ODP-1) further reinforceV the importance of operator engagement to identify deviations in valve operation, including system flows, levels, or pressures, that could indicate seat leakage or failure to fully close.
These procedures and practices are consistent with ISTC-5131(d) and ISTC-5151(d), which require recording any abnormality or erratic action during valve strokes. APS is not seeking relief from these provisions of ASME OM-2012. The procedures discussed above ensure operators are sensitive to equipment performance. Operators generate condition reports when a valve does not operate as expected or fails to produce the expected indication of system response. Valves in VRR-02 are subject to the same standards as other plant equipment.
Seat leakage testing requirements will continue to be met as applicable. VRR-02 includes 15 category A valves and 13 category B valves. ISTC-3600 requires leak testing for category A valves. All 15 category A valves are containment isolation valves tested in procedures 73ST-9CL01, Containment Leakage Type B and C Testing, and 73ST-9CL07, Containment Ventilation Purge Isolation Valves (8-Inch) - Penetration 78 and 79, per Appendix J to 10 CFR 50. There are no leak testing requirements for category B valves. For category B valves in VRR-02, operators will continue to apply ODP-1 to look for system indications of full closure. If evidence of leakage is identified for a category B valve, operators enter it into the corrective action program per Procedure 01DP-0AP12.
The PVNGS procedural framework and standards ensure operators assess the operational readiness of the valves in VRR-02 on each stroke. Station requirements for operational conduct, procedure use, and corrective action reporting drive operators to monitor valve performance, look for abnormal or erratic actions, and verify successful closure. The standard applies to PVNGS equipment broadly and will continue to apply WRthe valves in VRR-02.This aligns with ASME OM-2012 requirements to record abnormalities or erratic actions.Seat leakage testing will continue for valves with seat leakage requirements.
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
Table 1 List of NOPs for valves in VRR-02 Valve Description Normal Operating Procedure (NOP)
CHNUV0527 Makeup to charging volume control tank bypass isolation valve 40OP-9CH01, CVCS Normal Operations CHAUV0580 Reactor makeup water to reactor drain tank outboard containment isolation valve (penetration no. 45) 40OP-9CH06, CVCS Miscellaneous Operations CHAUV0560 Reactor drain tank outlet inboard containment isolation valve (penetration no. 44) 40OP-9CH06, CVCS Miscellaneous Operations CHBUV0561 Reactor drain tank inboard containment isolation valve (penetration no. 44) 40OP-9CH06, CVCS Miscellaneous Operations CPAUV0004A Containment power access purge supply outboard containment isolation valve (penetration no. 78) 40OP-9CP01, Containment Purge System CPAUV0004B Containment power access purge exhaust inboard containment isolation valve (penetration no. 79) 40OP-9CP01, Containment Purge System CPBUV0005A Containment power access purge supply inboard containment isolation valve (penetration no. 78) 40OP-9CP01, Containment Purge System CPBUV0005B Containment power access purge exhaust outboard containment isolation valve (penetration no. 79) 40OP-9CP01, Containment Purge System GAAUV0001 High pressure nitrogen supply header outside containment isolation valve (penetration no. 30) 40OP-9SI03, Safety Injection Tank Operations SGBHV0200 Chemical injection isolation valve (penetration no. 11) 40OP-9SC09, Operation of the Secondary Chemical Addition System SGBHV0201 Chemical injection isolation valve (penetration no. 12) 40OP-9SC09, Operation of the Secondary Chemical Addition System
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
Table 1 List of NOPs for valves in VRR-02 Valve Description Normal Operating Procedure (NOP)
SGEUV0169 Main steam isolation valve bypass valve (penetration no. 2) 40OP-9SG01, Main Steam SGEUV0183 Main steam isolation valve bypass valve (penetration no. 3) 40OP-9SG01, Main Steam SIBUV0631 Safety injection tank 1A fill/drain isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0638 Safety injection tank 1A check valve leakage test line isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0641 Safety injection tank 1B fill/drain isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0648 Safety injection tank 1B check valve leakage test line isolation valve 40OP-9SI03, Safety Injection Tank Operations SIAUV0682 Safety injection tank fill line containment isolation valve (penetration no. 28) 40OP-9SI03, Safety Injection Tank Operations SIBUV0611 Safety injection tank 2A fill/drain isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0618 Safety injection tank 2A check valve leakage test line isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0621 Safety injection tank 2B fill/drain isolation valve 40OP-9SI03, Safety Injection Tank Operations SIBUV0628 Safety injection tank 2B check valve leakage test line isolation valve 40OP-9SI03, Safety Injection Tank Operations
PVNGS Unit 1, 2, and 3 Response to Request for Additional Information Valve Relief Request 02
Table 1 List of NOPs for valves in VRR-02 Valve Description Normal Operating Procedure (NOP)
SSBUV0200 Hot leg sample line outboard containment isolation valve (penetration no. 42C) 74OP-9SS01, Primary Sampling Instructions SSBUV0201 Pressurizer surge line sample line outboard containment isolation valve (penetration no. 42A) 74OP-9SS01, Primary Sampling Instructions SSBUV0202 Pressurizer steam space sample line outboard containment isolation valve (penetration no. 42B) 74OP-9SS01, Primary Sampling Instructions SSAUV0203 Hot leg sample line inboard containment isolation valve (penetration no. 42C) 74OP-9SS01, Primary Sampling Instructions SSAUV0204 Pressurizer surge line sample line inboard containment isolation valve (penetration no. 42A) 74OP-9SS01, Primary Sampling Instructions SSAUV0205 Pressurizer steam space sample line inboard containment isolation valve (penetration no. 42B) 74OP-9SS01, Primary Sampling Instructions