ML26023A067
| ML26023A067 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 07/29/2025 |
| From: | Arnold E Arizona Public Service Co |
| To: | Thomas Scarbrough NRC/NRR/DEX/EMIB |
| References | |
| Download: ML26023A067 (0) | |
Text
Cost-Informed Management of Motor-Operated Valve Programs Eli Arnold July 29, 2025
Introduction
Test period extensions Maximizing test periods within available rules
4 Legacy test frequencies Program population: 312 Conservatism in outage test periods 4.5 years vs. 6 years (3 cycles vs. 4 cycles) 7.5 years vs. 9 years (5 cycles vs. 6 cycles)
Valves on a 3-year frequency 75 of 312 = 24%
New valves installed 6 of 312 = 2%
5 Test period extension basis Baseline + 2 tests Minimum 6 years of data, III-3310(b)
Margin rate of change
=
Test period determination Margin > 10%
6 Multi-part approach Evaluate within JOG Program requirements Single valves Programmatically Evaluate to Appendix III periods as an investment Update GL 89-10 and 96-05 commitments Parallel activity Update test periods per investments Evaluate to Appendix III requirements Apply to more valves Future: Apply OMN-26 in the future
Burden determination Measuring level of effort
8 Burden Each diagnostic test requires planning, scheduling, field performance, data evaluation, records processing Test less often, reduce cost of test program implementation 6-year test period = 1 test per 6 years burden = 0.17 tests/year 10-year test period = 1 test per 10 years burden = 0.1 tests/year Relative reduction 40% =
0.10.17 0.17 100 Testing rate metric
9 Program burden Testing rates can be summed Aggregate burden is the total testing rate for site/unit Summations can be used to compare between sites/units*
Unit A
- Both valves on 10-year test period
- Units burden = 0.2 tests/year Unit B
- One valve on 10-year test period, one valve on a 6-year test period
- Units burden = 0.27 tests/year Example: 2-unit site, 2 valves per unit
10 Comparison Palo Verde, 3 units, 104 valves per unit Actual test/year: U1: 16.3, U2: 15.6, U3: 16.2 Theoretical tests/year: 10.4 per unit Site testing rate Pre: 67.4 tests per year Post: 48.1 tests per year
- Normalize tests/year per valve Compare units with different numbers of MOVs Palo Verde Unit 1: 0.16 tests/year per valve
GL commitments From JOG Program to Appendix III
12 Established guidance NUREG-1482, 4.2.13:
The NRC staff considers that the implementation of Mandatory Appendix III for MOVs within the scope of the OM Code will meet the requirements of 10 CFR 50.55a(b)(3)(ii) provided the specified regulatory conditions are satisfied.
Licensees need to follow their commitment change process when updating their MOV program from the JOG final MOV test program to the new requirements of Mandatory Appendix III.
Appendix III meets 10 CFR 50.55a requirements for MOV program Acceptable to credit GL commitments to Appendix III Interpretation
13 Appendix III for GLs Max test periods for high-risk valves JOG: 6 years Appendix III: 10 years 50% of Palo Verde MOVs are high-risk Access to OMN-26 12-year max for high-margin, high-risk 16-year max for high-margin, low-risk
Conclusion
Questions