ML25183A353
| ML25183A353 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/2025 |
| From: | Jeffrey Poehler NRC/RES/DE |
| To: | |
| Jeff Poehler 3014158353 | |
| Shared Package | |
| ML25183A340 | List: |
| References | |
| Download: ML25183A353 (1) | |
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Z AA AB AC AD AE AF AG AH AI AJ AK AL AM AN AO AP AQ AR AS Panelist 1 Panelist 2 Panelist 3 Panelist 1 Panelist 2 Panelist 3 Average Recommendation ID title of recommendation
- Scope, objectives, and/or topic modifications Importance Uncertainty Knowledge Rationale for scoring Importance Uncertainty Knowledge Rationale for scoring Importance Uncertainty Knowledge Rationale for scoring Importance (score)
Uncertainty (score)
Knowledge (score)
Importance (score)
Uncertainty (score)
Knowledge (score)
Importance (score)
Uncertainty (score)
Knowledge (score)
Importanc e (avg)
Uncertaint y (avg)
Knowled ge (avg) error bars Import Uncert.
Know error More research could be used to gain knowledge on a topic expected to be important to safety More research could reduce uncertainty and clarify topic importance More research could improve knowledge but topic not expected to be safety significant Topic expected to have safety significance but likely could be addressed without additional research Topic may have safety significance but sufficient knowledge exists to manage Topic not expected to have safety significance and sufficient knowledge exists K/PK/UK K/PK/UK K/PK/UK RVI-1 Develop a comprehensive database for legacy and current reactor materials, including fabrication records, microstructural characterization, and degradation indicator benchmarking.
H L
PK L
M PK This would be nice to do, and help with prediction of degradation, but is probably something the industry should do versus NRC.
H M
K 3
1 2
1 2
2 3
2 1
2.3 1.7 1.7 0.277778 2.0000 2.0000 1.6167 0.333333 1
RVI-2 Establish and maintain robust knowledge retention systems and best practices so that we can integrate expert judgment with machine learning tools for aging management H
M PK M
M PK Fairly important to have knowledge retention L
L K
3 2
2 2
2 2
1 1
1 2.0 1.7 1.7 0.277778 2.6667 2.3333 1.6917 0.388889 2
RVI-3 Develop degradation models that can better reduce reliance on extrapolation and better predict complex interactions between SCC, fatigue, thermal aging, and irradiation effects.
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M UK I feel like this is an area (synergistic effects) where there is very little research or knowledge. These effects are difficult to simulate in the lab.
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2.7 2.7 2.7 0.444444 2.0000 2.3333 2.6667 0.388889 3
RVI-4 Set up coordinated material harvesting efforts to collect and test materials that have been inside reactors for years.
Focus on the most affected components to compare real-life changes with lab predictions H
M PK H
M PK Harvesting can provide important data for understanding degradation of RVI materials during long-term operation. Harvesting allows obtaining materials with operating conditons (thermal, radiation) which are difficult to impossible to replicate in laboratories.
M M
PK 3
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2.7 2.0 2.0 0.333333 1.6667 2.3333 1.9300 0.388889 4
RVI-5 Quantify the effects of microstructural and environmental changes (such as moisture or chemistry) on corrosion initiation, propagation, and wear in material grain boundaries H
H PK L
H PK I don't really understand what "moisture" means in this context since all RVI are in a reactor water environment.
H M
PK 3
3 2
1 3
2 3
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2.3 2.7 2.0 0.444444 2.3333 2.3333 1.9900 0.388889 5
RVI-6 Create models and establish experimental studies to quantify the effects of irradiation, transmutation, and gas accumulation on phase stability and mechanical degradation H
H UK M
M UK Transmutation due to irradiation is an area that has not been much investigated, so I think that research on this could be valuable. These second order effects (also including gas accumulation) could potentially become important during LTO.
M M
PK 3
3 3
2 2
3 2
2 2
2.3 2.3 2.7 0.388889 2.3333 1.3333 2.6167 0.222222 6
RVI-7 Identify the thresholds and environmental conditions which lead to non-linear property changes, focusing on high fluence and long-term exposure M
H UK H
M PK As operating time increases, I think it's important to understand if there are thresholds for more sever degradation due to mechanisms such as void swelling and IASCC.
H H
PK 2
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2.7 2.7 2.3 0.444444 1.6667 1.6667 2.3583 0.277778 7
RVI-8 Conduct experiments to evaluate and mitigate IASCC using post-irradiation annealing, advanced alloys, and powder metallurgy.
L H
UK L
M UK Although annealing could be an interesting strategy to mitigate IASCC, it seems more likely that plant owners will continue to manage IASCC through monitoring and analytical evaluation. PM materials could be used for replacement parts, but wholesale replacement of major internals components doesn't seem likely. I do think that this is a fairl y low knowledge area for irradiated stainless steels.
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1.3 2.0 2.7 0.333333 2.0000 1.3333 2.6167 0.222222 8
RVI-9 Accelerate guidance on qualification and licensing of advanced materials and repair methods.
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UK H
M PK I think it will be important to have tools like laser welding and materials such as AM materials and materials with enhanced IASCC resistance available.
H H
UK 3
3 3
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3.0 2.7 2.7 0.444444 1.3333 1.0000 2.6367 0.166667 9
RVI-10 Develop next-generation NDE techniques for early-stage damage detection that are operable in high-radiation environments.
H H
UK M
M PK Important to be able to detect flaws early.
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PK 3
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2.0 2.7 2.3 0.444444 2.0000 2.0000 2.3833 0.333333 10 RVI-11 Improve repair and replacement strategies for irradiated components that align with ALARA principles and long-term safety needs.
H M
PK L
M PK This recommendation is a bit vague to act on, although it generally sounds like a good idea.
L L
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1.7 1.7 1.7 0.277778 2.0000 3.0000 1.7167 0.5 11 RVI-12 Strengthen partnerships between labs, industry, and regulators so research gets turned into practical solutions faster.
L L
M M
PK This seems like a good goal, especially in light of likely declining research budget at NRC in coming years.
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K 1
1 1
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1.3 1.3 1.3 0.222222 2.0000 1.6667 1.3833 0.277778 12 0.0 0.0 0.0 0
1.6667 2.0000
-0.0250 0.333333 13 0
2.0000 1.6667 0.0500 0.277778 14 H
M K
All of this information should be known and available somewhere.
Addition or upgrade to REAP?
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H UK M
M PK H
M PK PK since we've done similar work, not necessarily for 80+
years though M
M PK H
H U
M L
PK H
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K score: H/M/L score: H/M/L score: H/M/L 1
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10 11 12 Importance Knowledge Reactor Vessel Internals High Low Known Unknown