ML24155A212
| ML24155A212 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 06/07/2024 |
| From: | Arnold E Arizona Public Service Co |
| To: | William Orders NRC/NRR/DORL/LPL4 |
| Orders, William | |
| Shared Package | |
| ML24155A213 | List: |
| References | |
| Download: ML24155A212 (1) | |
Text
VRR-03: SOV Test Criteria Eli Arnold, IST Program Owner June 7, 2024
Alternative Request Summary Current Requirements Alternative Requirements Alternative Justification Duration of Proposed Alternative Conclusion Agenda
3
- Reason for the request:
Palo Verde desires to apply only the upper acceptance of ISTC-5152(a) (+25%) and ISTC-5152(b) (+50%)
for solenoid-operated valve performance monitoring.
There is no technical basis for applying the lower acceptance criteria (-25% and -50%).
Alternative to requirements of ASME OM-2012 No industry precedents Alternative Request Summary
4 Current Requirements
5 Current Requirements
6 Current Requirements
7 Alternative Requirements Requirements:
ISTC-5152(a) acceptance criteria +25%
ISTC-5152(b) acceptance criteria +50%
Summary:
Only increasing stroke times shall be subject to evaluation per paragraph (b) in ISTC-5153, Stroke Test Corrective Action
8 Vendor FMEAs and troubleshooting guides show all identified failures contribute to increased stroke time. None of the indication, electromagnetic, nor mechanical issues identified could reasonably be expected to decrease stroke time.
EPRIs Solenoid Operated Valve Maintenance Guide shows SOV performance degrades via increasing stroke times. It has no examples of failure modes identified from decreasing stroke times.
Alternative Justification
9 Example ISTC-5152(c) - threshold for evaluation is a hard limit. No requirement to evaluate stroke times below the limit Alternative Justification
10 The proposed alternative shall be used for the duration of Palo Verdes fourth 120-month in-service testing interval, which ends January 14, 2028.
Duration of Proposed Alternative
11 Palo Verde can provide an acceptable level of quality and safety in SOV performance monitoring by eliminating the OM-2012 requirement to apply a lower stroke time acceptance criteria.
Vendor documentation and industry research shows rapid closure is not an SOV failure mode of solenoid-operated valves Only the upper acceptance criteria of ISTC-5152(a) and ISTC-5152(b) provide insight into valve condition.
Conclusion