ML25183A350
| ML25183A350 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/2025 |
| From: | Jeffrey Poehler NRC/RES/DE |
| To: | |
| JEFF POEHLER 3014158353 | |
| Shared Package | |
| ML25183A340 | List: |
| References | |
| Download: ML25183A350 (1) | |
Text
1 2
3 4
5 6
7 8
9 10 11 12 13 14 15 16 17 A
B C
D E
F G
H I
J K
L M
N O
P Q
R S
T U
V W
X Y
Z AA AB AC AD AE AF AG AH AI AJ AK AL AM AN AO AP AQ AR AS AT AU AV AW AX AY Panelist 1 Panelist 2 Panelist 3 Average Recommendation ID title of recommendation Scope, objectives, and/or topic modifications Identified Parts and Components (SSC)
- Any Named Materials (M)
- Identified Environment/Co ndition ( E )*
Any Named Degradation/ag ing mechanisms (A)
- Critical factors controlling occurrence in plant
- Other columns to be added at discretion of each PIRT pane Score Rationale Score Rationale Score Rationale Score Rationale Score Rationale Score Rationale Score Rationale Score Rationale Score Rationale Importance (avg)
Uncertainty (avg)
Knowledge (avg) error bars Import Uncert.
Know error More research could be used to gain knowledge on a topic expected to be important 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 H/M/L H/M/L K/PK/UK H/M/L H/M/L K/PK/UK H/M/L H/M/L K/PK/UK BOP-1 Research supporting enhanced predictive maintenance through modeling, use of monitoring and inspection data, and forecasting.
CHECKWORKS process for BOP; BPWORKS (buried pipe) is what industry uses; input information not always provided; ID and OD effects.
Piping, tanks Any Any Any M
I like the idea of continuing to develop checkworks-like tools for BOP. Because BOP challenges are more varied than FAC and inspections may not be as regular, maintaining and updating tools may be challenging H
I've got fairly significant uncertainty on my ranking primarily because I'm unsure how much monitoring and inspection data exists to perform sufficient updates. I'm also unsure how widely the tools are shared among the industry and how much tool-usage guidance exists.
PK general knowledge of degradation mechanisms is good to inform tool prognoses. Plant specific differences may be less well understood, which requires appropriate updating through monitoring/inspection. Biggest challenge is accessibility for monitoring/inspection.
M This is an important area, but a lot of work has been done and I am not sure more research would provide value.
L Systems such as EPRI BPWorks and SI MAPPro are already available and seem to work reasonably well, though there could probably be refinements to improve the software in the future.
PK High-level knowledge of BPWorks, MAPPro.
H General note in Importance ranking for several recommendations: taking into account higher risk of some BOP systems (e.g., fire water piping, some service water)
A dedicated consensus program with industry buy-in could be very impactful in collecting and sharing OE -
and establishing clear plant expectations - that are based on data and projections (inspection method/frequency, acceptance critiera, corrective actions)
M General consensus in the workshop panel on the value of a program that supports sharing of OE and having a cooperative industry effort to establish best practices for maintaining BOP systems -
particularly buried pipe However, acknowlege practical difficulties in modeling disparate corrosive environments (e.g.., soils, etc.)
PK Generally good knowledge of corrosion mechanisms; however, not fully immersed in BOP aging management tools (like the BPWorks) -
relying on shared insights from the workhop panel 2.3 2.0 2.0 0.333333333 2.3333 2.0000 1.9750 0.333333 2
1 1
2 BOP-2 Research on high-resolution ultrasonic imaging and encoded data collection to ensure accurate corrosion morphology evaluation, including identifying degradation thresholds and improving flaw sizing.
Piping, tanks Metallics Any Loss of material L
I don't really think that research in this area is needed. UT techniques have generally enough accuracy to measure wall thining.
While cracking and dealloying are more difficult to assess, there should still be sufficient accuracy given margins. The biggest challenge is gaining access and implementing over long inspection M
I have moderate uncertainty as maybe there are UT accuracy challenges in these systems are greater than I expect, largely due to accessibility or coupling issues PK UT techniques are well established; the biggest potential knowledge gap results from its implementation in BOP systems M
This is an important area, but a lot of work has been done and I am not sure more research would provide value.
M High resolution UT and encoded data collection is already being done, though improvements can be made.
PK Topic has come up at EPRI meetings. Not an expert.
L Fine-tuning UT capability expected to yield only small, incremental safety benefits.
Research better put towards "far-field", remote capabilities M
Any means to improve volumetric inspections (particularly remotely) has the potential to increase capabilty to define piping condition; however, reasonably certain more research in this area would not have a great impact on safety PK Reasonable knowledge of degradation mechansims.
UT techniques are fairly mature
- however, limited 1.3 2.0 2.0 0.333333333 1.3333 2.0000 1.9750 0.333333 2
3 3
2 BOP-3 Develop standardized guidelines for defect characterization and acceptable defect sizes in inspection and repair processes min wall thickness is often limiting condition and is generally what is meant by "acceptable defect sizes" Piping, tanks Any Any Any L
While developing more rigorous acceptance criteria is always welcome, I don't believe that this is needed to maintain safety.
Given that the loads in these systems are generally small, except possibly during accidents in some systems, I think that current ASME criteria are sufficient in this regard.
M There may be some instances where ASME criteria isn't sufficient or possibily some non-ASME components/systems that are nontheless safety significant that may have lacking acceptance criteria PK ASME rules concerning minimum wall thickness and Section XI flaw acceptance standards are well understood. The only area where new work may be needed is related to dealloying. However, it's conservative just to ignore integrity of the active dealloying region L
Based on engineering judgement, I would rank this below other areas such and new repair and inspection techniques.
L This seems well understood but maybe improvements can be made.
PK Topic has come up at EPRI meetings. Not an expert.
L The availability of new standarized defect characterization guidelines (such as for min wall) is not considered to have a strong impact on safety.
It's probably more important that plants are committed to doing something with that information - such as following a well estabished process to react trend and share OE M
Importance ranking based on most common materials/aging effect - e.g.. steels and wall thinning due to general corrosion. This is well known ground.
However, the importance could increase when considering non-tradiational materials, such as polymers &
polymer/composite repairs PK Characterizin g and assessing most common BOP piping defect (min wall) is common practice.
1.0 1.7 2.0 0.277777778 1.0000 1.6667 2.0000 0.277778 BOP-4 Develop real-time monitoring techniques soil resistivity sensors; flow ball with sensor to check for leaks; improved guided wave sensors mounted on piping systems Piping, tanks Any Any Any M
It's always a good idea to pursue real-time monitoring and I would never discourage that. However, periodic inspection is more important given the relatively slow time fram associated with degradation that I feel like resources are better spent there.
M Developing techniques could certainly maintain or even enhance safety but I don't think they are needed to maintain safety which is why I have moderate uncertainty.
PK Physics associated with some monitoring techniques is well understood, less so for others.
Implementation and reliability are biggest challenges with monitoring techniques M
These would be a "nice to have" but I consider them a supplement to existing inspection techniques.
H To my understanding, research in these areas is in the early phases.
PK I have heard about these in EPRI presentations but am not an expert.
M Unclear if the "real-time" aspect has a strong effect on safety May be a "nice-to-have", but periodic inspection with guided wave (for example) would also be sufficient Practically may result in more inspections being done, given cost-constrainsts in excavations & licensees justifying not doing inspections M
Though the value of "real-time" was downplayed in the inportance ranking, it's acknoweldged that some techniques (like the flow ball) could offer a unique way to investigate an entire piping length (as opposed to the sampling based approach tradationally used) - this could offer safety benefits (like finding incipent leaks before a major issue arises)
M Limited personal knowledge of real-time technicques 2.0 2.3 1.7 0.388888889 2.0000 2.3333 1.6417 0.388889 BOP-5 Develop advanced NDE techniques for large-diameter pipes and buried infrastructure should be developed to enable efficient, far-field, and above-ground inspections inspection without excavation Piping Metallics Any Any M
Even though I ranked this as medium, I believe that this has the most potential upside compared to the other monitoring and inspection ideas. The challenge is in developing effective far field techniques given the low expected technical low readiness level of such techniques in general.
Inspecting through access points (which is already done) is likely a much more obtainable strategy than far-field above ground H
I'm not really cognizant of research in this area and how viable such techniques are. I do not recommend supporting research if the success likelihood isn't reasonable PK I don't have strong knowledge in this area. I know that there are leakage and tritium detection techniques that may be feasible for remote sensing, and there are pig delivery systems that are currently used. I'm less knowledgable about their accuracy however such that limitations and needs aren't clear to me.
H Important due to potential failure impacts (flooding)
M There are techniques available but more work can be done.
PK Topic has come up at EPRI meetings. Not an expert.
H Has the potential to signifinctly increase the extent of inspections, given the practialities and cost-constraints in examining piping of limited-to-no accessibility (e.g., needing to do excavations)
L Any means to improve remote inspections has the potential to significantly increase the amound of data collected and the capabilty to define piping condition PK Limited personal knowledge of the latest advancement s in far-field techniques;
- however, general familiary with the challenges of 2.7 2.0 2.0 0.333333333 2.6667 2.0000 2.0000 0.333333 BOP-6 Development of advanced methods to inspect CIPP/SIPP and ensure long-term reliability potentially would consider inspection of substrate, interface, and composite/resin structure and ply interfaces depending on system.
Piping Non-metallics Any Any H
given prevelance and expected future use of these repairs, this is a needed area of future research IMO; visual and tap testing are most common techniques for non-metallic systems and they have obvious limitations M
The biggest uncertainty for me in this area stems from the general lack of long-term OpE on such systems. If safety-significant CIPP/SIPP and other non-metallic systems perform adequately long-term, such inspection techniques are not needed. Conversely, if there are issues, it's harder to know the exent of repairs that are appropriate without adequate inspection tools.
PK Research is underway on this topic. Such research should ideally be coupled with expected long-term degrdation mechanisms ton ensure that NDE can locate relevant indications.
H We know these materials will be used more in the future, and inspecting them will be a critical need.
H I don't have a lot of knowledge, but I assume there is a lot of research needed in this area.
UK See Uncertainty column.
H CIPP/SIPP likely to see greater use N-871 (carbon fiber) ISI relies on visual, pressure test, accoustic tap; these aren't truely interrogative and have questionable efficacy Note: sucessful non-nuclear appliations of these repar technologoes are often cited (with some, but limited long-term experience)
M Limited OE (particularly with nuclear) creates uncertainty if aging (and ability to inspection) is really an issue Also, if new polymer/composite systems are introduced, unclear if new/different aging may occur PK Polymer resistance to water-based aging is fairly well-known, but nature of composite and other materials (e.g.,
continued adherence of layers, etc.)
introduced more uncertainties Unknown aging implications of less-than-ideal material construction.
3.0 2.3 2.3 0.388888889 3.0000 2.3333 2.3333 0.388889 BOP-7 Develop new materials and water treatments that align with updated safety, economic and environmental requirements that offer enhanced corrosion resistance.
develop more impervious systems.
Piping, tanks Any Any Any M
Work to develop new materials would be laudable, but the development and then replacement costs will likely be prohibitive such that wholesale replacement is highly unlikely.
There are current non-metallic options which show promise.
Water treatment options should be known.
M Biggest uncertainty pertains to water treatment and possibility of using it to slow damage. Viable treatment methods should be known, with the biggest uncertainty being the cost and potential environmental challenges with implementation. there is certainly experience in other related industries. The only replacement materials which make sense are the nonmetallics sleeves (metallic replacement will be too costly) so uncertainty is low that other replacement PK Certainly much is know about possible replacement materials and water treatments. Biggest challenge is tailoring that knowledge to unique nuclear environments and minimizing the implementation costs.
L I just see it as unlikely that we would pursue new materials/treatments instead of working with what we currently have. I am not considering CIPP/SIPP/CFRP as "new".
H There would be a high degree of uncertainty if this was pursued.
PK No knowledge of "new materials" and some knowledge of water treatments.
L The development of new materials and water treatments would likely have only incremental impact on safety of plants that are already 50 years old - new materials would be applied only to repairs; thus, the impact of more reasearch in this area would be limited Better to focus on NDE M
When considering new repair materials (such as composites), the importance could increase PK Limited personal knowledge of the very latest development s on water treatments and whether there are practically impactful research benefits 1.3 2.3 2.0 0.388888889 1.3333 2.3333 2.0250 0.388889 BOP-8 Evaluate effectiveness of cathodic protection, coating, and chemical treatments "effectiveness" means that current protections will continue to be effective at 80 years of operation and beyond.
Piping, tanks Metallics Any Any M
Research in this area may be helpful; however, I have no reason to expect that CP or chemical treatments will stop being effective. Coatings will certainly degrade. Therefore, understanding coating stressors is important but developing/implementing inspection and acceptance criteria for coating may be more important or just mitigating assuming that coatings are no longer effective.
M I'm fairly certain that water treatments and CP will maintain effectiveness over life unless evidence of an unknown saturation or similar phenomena is identified; coatings are a bigger challenge because of expected degradation with time and service.
PK I think that there's generally good knowledge in this area; certainty CP, and chemical treatments are known; need to continue to mine public water and sewage OpE; the analogy isn't perfect but there's longer history than nuclear.
Increased knowledge of coating degradation may be helpful.
L These are important, my ranking is L due to our current understanding and limited impact of additional research.
L We know coatings, water treatments, and cathodic protection are effective (coatings less so as they age beyond 80 years).
K Extensive knowledge of cathodic protection and coatings, less so for water treatments.
L The effectiveness of cathodic protection seems to be more dependent on site configurations and the plant's commitment to maintaining the system. It's not clear if reseach would markedly improve safety.
For coatings, additional research is considered to have only a very limited benefit on existing (50 year old) coatings that have been already applied under varying M
Although certainty of importance rating is fairly high, the lack of personal knowledge on the practical implementation of cathodic protection and coating technologies created uncertainties PK Only basic knowledge of cathodic protection and coatings 1.3 1.7 1.7 0.277777778 1.3333 1.6667 1.6667 0.277778 BOP-9 Develop methods to assess the long-term effectiveness of repairs and treatments, including mechanical and chemical stability separate metallic and non-metallic consideration may be appropriate for items BTP-7, 8, and 9 Piping, tanks Any Any Any M
This topic is coupled with BTP-8 as well as the prior inspection topics: I expect biggest unknowns to be long-term effectiveness on non-metallic repairs. While it's important to understand attributes affecting long-term performance, effective monitoring/inspection (e.g. NDE) decreases the need for such knowledge.
L Research would be helpful because there is little OpE associated with nonmetallics.
However, I don't think that the importance should be elevated to high based on this lack of knowledge. Nonmetallics should be impervious to corrosion effects but may be degraded by thermal cycles and debris. Therefore, OpE should be carefully monitored.
PK We have some OpE pertaining to metallic repair and treatment.
There's much less OpE and knowledge associated with long-term effectiveness of non-metallic repair techniques H
This is a key question for LTO beyond 80 years.
H I assume this would involve accelerated corrosion/mechanical testing, which has inherent high uncertainty.
PK Experience performing accelerated corrosion testing.
M Interpreting the issue as the means to predict the long-term efficacy of polymeric repairs by doing shorter-term testing Increased use of polymeric reparis makes this an increasingly important issue Sucessful non-nuclear applications of these repar technologoes are often cited (with some, but limited long-term experience)
M Limited OE (particularly with nuclear) creates uncertainty if aging (and ability to predict performance) is really an issue Also, if new polymer/composite systems are introduced, unclear if new/different aging may occur PK Polymer resistance to water-based aging is fairly well-known, but nature of composite and other materials (e.g.,
continued adherence of layers, etc.)
introduced more uncertainties Unknown aging implications of less-than-ideal material construction.
2.3 2.0 2.0 0.333333333 2.3333 2.0000 2.0250 0.333333 BOP-10 Better understanding of attributes (e.g., soil conductivity/chemistry) driving external corrosion that could affect repair (e.g., CIPP) lifespan.
Piping Metallics L
CFRP is currently not taking credit for the host pipe within the repair region. Further, external corrosion is an integrated problem and soil chemistry is just one consideration. However, the bonded region is potentially a concern if external corrosion weakens the bonded region.
Monitoring/inspection may be better approach within areas of concern L
This topic has some potential somewhat important but soil chemistry is just one variable affecting external corrosion.
Regardless, external corrosion may only be a concern in certain situations if the repair region doesn't credit the substrate material.
PK External corrosion factors are generally well known and there's certainly plant OpE to rely on in this area as well. Biggest unknowns are likely to be localized corrosive regions or site-specific challenges.
M Only M due to being one factor that controls external corrosion. Also does not consider ID effects.
H I have seen efforts to determine corrosion rates from soil corrosivity data, which have largely been unsuccessful. Soil corrosivity data provides a qualitative look on environment aggressiveness, and I'm not sure more research would provide value.
K Experience from performing LR/SLR reviews and attending EPRI meetings on the subject.
L Not convinced safety would be significantly enhanced by additional research. Effect of soil chemistry on metal corrosion has been well studied.
L Reasonable certainty than any developments in this issue would only introduce incremental benefits External corrosion is fairly well understood - issue more significantly affected by installation QA (for CIPP) and inspection capability K
Corrosion well understood 1.3 1.7 1.3 0.277777778 1.3333 1.6667 1.3333 0.277778 BOP-11 Understand impacts of ground settlement on piping ovalization and its impact on structural integrity over time.
Piping Steel M
This topic is interesting, mainly because I'm not aware of any work done in this area. However, I don't expect ovalization to be an issue by itself but would likely only affect integrity if coupled with another degradation mechanism.
It might be a bigger concern under seismic loading M
My ranking has moderate uncertainty. While I'm unaware of any studies in this area and if compaction really will transmit significantly higher loads, I don't expect this to be the case, even under seismic loading, as ovalization requires loads approaching plastic values.
UK Ovalization effects in standard piping systems are generally secondary effects unless deadweight type forces approach plastic values. I would expect that similar magnitudes would be needed to affect buried pipes.
H This seems important, I just have limited knowledge.
H I have limited knowledge, but I assume this has a high degree of uncertainty.
UK This seems important, I just have limited knowledge.
L Engineers know how to evalute external loads on piping, alhough soil compaction creates additional complexity Not that settlement isn't an issue, but evaluations/solutions would L
The issue seems straightforward and the impact of research would seem to be limited - its about applied load and proactively evaluating the structural capacity of a pipe PK Although the broader capabilty to assess structural loads on piping is
- known, recognize 2.0 2.0 2.7 0.333333333 2.0000 2.0000 2.6667 0.333333 BOP-12 Investigate selective leaching to address fracture initiation and microstructural changes and their impact on structural integrity.
geared more toward cast iron alloys Piping, tanks Cast Irons, mainly gray cast iron Any Selective Leaching M
This seems like a reasonable area of research although it only affects cast, and some ductile iron alloys.
I'm not aware of any work to evaluate residual strength after dealloying but a conservative assumption is just to assume affected material doesn't carry load. While it's possible that dealloying may lead to crack-like initiators, I expect them to behave more like pores such that they don't promote brittle fracture M
While the topic is interesting and I have some uncertainty about the brittle fracture possibilities, I still expect that Code margins remain appropriate if the components are treated conservatively by assuming the dealloying region carries no load. I could most likely see research being performed to reclaim structural margin.
PK There's general knowledge on leaching mechanisms and principal causal factors. I'm less aware of research linking leaching extent and magnitude with structural intergrity.
M Only M due to limited material applicability.
M We know that this is an issue, but this may not be a problem that can be solved. Piping susceptible to brittle fracture should just be replaced.
K Experience performing LR/SLR reviews related to selective leaching.
M This issue often is not acknowledged and has not been well explored Selective leaching is almost a certainty in many cases, and understanding implications on fracture is important - has potential for catastrophic failure Howeer, this is heavily focused on one material (cast iron) and uncleare if there is a wide enough impact to rank high M
Uncertainty between M and H for Importance. Selective leaching is one of those aging issue that has the potential to manifest somewhat catosphrophically However, this is mostly a one-material issue. Also, plants will continue to replace susceptible and/or degraded pipe PK Selective leaching is a fairly well-known, but it can be difficult to predict (particularly locally). The details on how it may affect catastrophic fracture initiation haven't really 2.0 2.0 1.7 0.333333333 2.0000 2.0000 1.6917 0.333333 BOP-13 Develop uniform testing and qualification criteria and associated QA/QC practices for onsite repairs that addresses variability in installation methods Piping, tanks Non-metallics Any Any H
This is an important concern with CFRP and other nonmetallic repairs that are performed onsite.
Unlike welding, which has relatively strict qualification requirements, there's significantly less basis associated and required for nonmetallic techniques L
The performance of these systems are strongly affected by the quality of the installation. However, they are qualified and designed based largely on idealized, laboratory-type fabrication.
PK There's certainly knowledge in this area pertaining to best practices.
What I believe is missing is a more systematic identification of critical variables and acceptable ranges, and then an understanding of the variation in performance both within and outside of those ranges.
H Ensuring adequate QA/QC (e.g., surface prep, cure time and temperature profile) is critical for these non-metallic repairs. NRR should address this when approving for safety-related applications and the regions should have some oversight to ensure that adequate QA/QC was followed.
L Common knowledge that adequate QA/QC is imperative for polymers/coatings.
K Experience with composites and coatings systems, both lab and field application.
M CIPP/SIPP likely to see greater use, and the effectiveness of the existing inspection methods are not great.
Hoever, N-871 (for composite repair) already has criteria for qualification (adhesion testing, etc.), and it's unclear if more "research" would result in significant increases in safety -
versus simply having addition Code discussions to make QA/QC as robust as possible.
Also, ISI is there to catch issues - therefore, making more research into install QC less safety significant M
With the existing qualification criteria in ASME, coupled with the inservice inspection, reasonably certain the safety impact of more research would be only incremental -
however, acknolwedge the current inspection limitations PK Personal knowledge of repair qualification is limited.
Familiar with the code case qualification requirements 2.7 1.3 1.7 0.222222222 2.6667 1.3333 1.6667 0.222222 Importance Uncertainty Knowledge
- (at discretion of each PIRT panel)
Importance Uncertainty Knowledge Importance Uncertainty Knowledge Importance Knowledge Balance of Plant 1
2 4
5 10 7
13 6
8 9
High Low Known Unknown 12 3
11