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Chuck Linden - AOV
	ML26023A061
Person / Time
Site:	Palo Verde
Issue date:	07/29/2025
From:	Linden C; Arizona Public Service Co
To:	Thomas Scarbrough; NRC/NRR/DEX/EMIB
References
	Download: ML26023A061 (0)
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ASME Valve & Pump Symposium 2025 Mandatory Appendix IV Implementation Chuck Linden - AOV Program Engineer Palo Verde Generating Station

2 AGENDA

Background

Mandatory Appendix IV OM-2022 Implementation of Appendix IV at PVNGS Path Forward

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Background===

AOV Programs in the industry previously implemented by the nuclear industry under INPO Document NX-1018, Revision 1 titled Joint Owners Group (JOG) Air Operated Valve Program. This document predates the 2017 version of the initial OM Code which requires for Air Operated Valves discussed in Mandatory Appendix IV Preservice and Inservice Testing of Active Pneumatically Operated Valve Assemblies in Nuclear Reactor Power Plants.

EPRI Technical Report 30030112918, ASME Operation and Mandatory Code: Mandatory Appendix IV Implementation Guide was issued in 2019 states that plants, which was voluntarily implemented under INPO Document NX-1018 have already completed much of the effort required to meet Appendix IV. AOV Programs previously established under INPO Document NX-1018 should only require some administrative changes to procedures and enhancements for analysis and evaluation processes to meet the code requirements which is in progress at Palo Verde Generating Station.

Mandatory Appendix IV is required by 10 CFR 50.55a Codes and Standards invoking Mandatory Appendix IV. Implementation of Mandatory Appendix IV will be required during the ASME 10-year OM Code update for Palo Verde Generating Station in 2028.

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4 Mandatory Appendix IV IV-3820 Risk-Informed Methodology AOVs shall be evaluated and categorized using a documented Risk Ranking Methodology.

Subsection ISTE provides an acceptable methodology for Risk Ranking.

Utilities should have developed Risk Ranking for their AOV Programs as defined by the INPO Document NX-1018 titled AOV Joint Owners Group Document.

Note:

Risk Ranking is the Foundation for meeting the requirements for Mandatory Appendix IV to have a successful AOV Program.

5 Mandatory Appendix IV IV-3821 High Safety Significant Components (HSSC)

AOVs classified as HSSCs require Performance Assessment Testing to assess functional margin The AOV JOG Document defines HSSCs as Category 1 AOVs which meets the requirements for Risk-Ranking methodology.

IV-3410 states PAT shall be performed within three refueling cycles or 5 years, which ever is longer following implementation of Appendix IV for pre-2000 plants.

IV-3410 states PAT shall be performed for post-2000 plants prior to plant startup or during plant startup activates.

6 Mandatory Appendix IV Requires establishing Performance Assessment Testing (PAT) for Air Operated Valves necessary to evaluate Functional Margin An increment or percentage by which the AOV is available as tested capability meets or exceeds the thrust/torque load required to operate under worst case conditions.

Test parameters which may be determined from data obtained during testing and are important to monitor (e.g. tracking and trending) to ensure functional capability.

Parameters should include but not limited to are bench set, spring preload, spring rate, full stroke time, valve travel, measured torque or thrust and seat loading.

Functional Margin as defined in IV-2000 Supplemental Definitions

7 Mandatory Appendix IV IV-3410 Performance Assessment Testing (PAT)

For pre-2000 plants, an initial PAT shall be performed within 3 Refueling Cycles or 5 years which every is longer following implementation of this Appendix to assess Functional Margin. Post 2000 plants shall perform this testing prior to plant startup or during plant startup activities.

Testing activities that were performed as part of the plants Legacy AOV Program can be used to satisfy PAT requirements of IV-1400(a).

PAT is required prior to Maintenance activities concurrently scheduled to support Tracking and Trending.

The interval for each AOV shall not exceed 10 years.

8 Mandatory Appendix IV IV-3000 General Testing Requirements Performance Assessment Test Stroke Time Test Fail Safe Test, if applicable.

Leak Testing in accordance with ISTC-3600 and ISTC-5000, as applicable Position Verification Testing Note:

PAT will be performed under the Air Operated Valve Program at Palo Verde Generating Station, while the remaining tests are already performed under the current Surveillance Testing Program.

9 Program Development Plan AOV Categorization - Completed KVAP 4.3 Software and calculations completed for Category 1 AOVs Contracted Kalsi Engineering to revise procedures for data acquisition using Teledyne FS3 diagnostics and performance assessment of test evaluation as discussed in IV-6000.

Guidance will be developed to analyze and evaluate the functional margin in accordance with IV-6400 The evaluation process will provide reasonable assurance of actuator margin meeting the acceptance criteria at present and during the PAT interval as required by IV-3410. This includes ensuring positive functional margin will be maintained over the next scheduled test interval.

Installation of KVAP 4.4 is projected by the end of 2025 or early 2026 Procedures are projected for completion by spring of 2026 to allow for testing administrative processes.

The process is expected to be operational by the end of 2026 in preparation for implementation of Mandatory Appendix IV.

Questions ????

Pre-Test Information

Pre-Test Setup Sheet

Tracking & Trending New Interface

Acceptance Criteria & Functional Margin MOV AOV

Tracking and Trending

Post Test Evaluation

App. III Post Test Evaluation

ML26023A061

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