ML23082A058
| ML23082A058 | |
| Person / Time | |
|---|---|
| Issue date: | 03/28/2023 |
| From: | Matthew Hiser NRC/NRR/DANU/UAL1 |
| To: | |
| References | |
| Download: ML23082A058 (1) | |
Text
NRC Staff Perspective and Feedback on ASME Draft Code Case on Alternate Rules for Non-Destructive Examination and Testing Matthew Hiser Senior Project Manager NRR/DANU/UAL1 March 28, 2023 Public Meeting
Context - Regulatory Guide 1.87, Rev. 2 2
- 2015 NRC Public Meeting presentation: UT in Lieu of RT for Nuclear Power Plant Applications (ML15009A025)
- NUREG/CR-7204, Applying Ultrasonic Testing in Lieu of Radiography for Volumetric Examination of Carbon Steel Piping
- ASME Section XI Code Case N-831-1 is endorsed by NRC for use in repair / replacement activities
- Applicable to carbon and stainless steel with performance demonstration and flaw analysis (Section XI acceptance criteria)
- Applied successfully in the operating fleet
- ASME Section III Code Case N-659-3 for Class 1 components, which is on the list of disapproved code cases in Regulatory Guide (RG) 1.193 3
UT in Lieu of RT for the Draft Code Case
- Areas for Further Clarification
- Code Case provides a limited technical basis to justify using UT in lieu of RT (ample basis was provided for N-831-1)
- Lack of detail on critical/allowable flaw sizes, etc.
- At high temperatures, construction defects are more vulnerable to creep-enhanced failure
- UT challenged at distinguishing between planar and volumetric flaws
- RT is challenged to identify planar flaws
- Lack of performance demonstration specified in Code Case
- 5% random sample for UT
- Technical basis for random sampling, and the proposed value? Statistical justification?
- Technical basis for sample expansion, and random RT or UT in lieu of targeted inspection of most susceptible/vulnerable location?
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Hydrostatic Testing
- Basis for the changes proposed to hydrostatic testing
- Code Case technical basis states: Section III Certificate Holder experience has shown that essentially no valves fail during the additional hold time past the required B16.34 holding times.
- Can industry provide data (sample size/scope, number of failures) to support this statement?
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Questions
- Cross-cutting
- Taking all of these changes together, how does this provide reasonable confidence that the component will perform its intended function?
- Scope / Applicability
- Is this Code Case applicable to LWRs or only for non-LWRs?
- Can you clarify that this is not applicable to safety-related components and intended to be applied to non safety-related with special treatment (NSRST) for RG 1.233?
- How does reducing the fabrication inspection effort impact the effectiveness of (or take into account) the Reliability Integrity Management (RIM) or in-service inspection (ISI) program during operation?
- Is there reasonable confidence that the component will perform its intended function for certain cases (e.g., not in 5% fabrication sample inspection and no ISI is required)?
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