All right Good morning everyone Welcome to both everyone here in the room and those attending virtually to the last day of the Rick It's great to see so many smiling happy people here joining us to talk about long-term operations for power reactors in our session Entitled long-term operations meeting the moment My name is Brian Smith, and I'm the director of the division of new and renewed licenses here at the NRC our division leads the licensing reviews for for license renewals and new plant licensing for light water SMR's With me today is John wise Lovey and Simone Haruku Sasaki and jen ho Lee There we go So as I said this session is titled long-term operations meeting the moment Here in the US and across the world as the power reactors age to their original license and into long-term operation We have seen various degradation issues arise According to the IAEA about two-thirds of the global fleet global reactor fleet of 413 reactors is over 30 years old Specifically here in the US for the fleet of 94 reactors 90 have exceeded 30 years of operation 54 have exceeded 40 years and with our oldest reactor having been being an operated for 54 years We've been busy for many years now with evaluating license renewals in the US Only nine reactors still have their 40 year licenses 78 have been initially renewed for 60 years and six have been subsequently renewed for up to 80 years With many more under review right now and and many more applications expected Luckily, we are not in this alone International cooperation continues to serve a valuable role in long-term operations Through this we were able to share Operating experience and emergent issues with our foreign partners like we have with us here today We're able to leverage research programs and share best practices and aging management and regulatory strategies We do this through bilateral engagements Such as on Monday when we met with Flavian to talk about thermal embrittlement of cast austenitic stainless steel and on Friday We're going to meet with Harakoo to discuss PWR coral barrel cracking and stress corrosion cracking And we've had ongoing discussions with jen ho and kins throughout the year We're also active in ongoing multilateral programs including the IEA's IGOL program and the NEA OECD working group on integrity and aging of components and structures Also note that here in the US. We are currently updating our SLR guidance with a planned issuance date of January 2025 We plan to have a public meeting next month in April to discuss how we resolve the public comments on the draft documents So look for that notice coming up for a long and lastly Research our officer research will be conducting a workshop this fall on Planning for research for operating beyond 80 years So if you're interested in that, please stop by and see one of us after the session So in this session we'll dive into aging degradation issues that have occurred during long-term operation This session will discuss case studies about different types of aging degradation that may impact long-term operation and the approach to addressing the issue Each case study will provide some background on the aging at degradation issue identified Describe the regulatory approach to evaluating the issue and actions to address it and discuss any lessons learned from this experience Including any research or regulatory process actions that have been taken or being considered Following the presentations we'll have a few predefined questions for the panelists, which will be followed by audience Q&A So a few notes about Q&A's but first since this is the first session of the day Please remember to silence your electronic devices The Q&A portion of this session will be through electronic means for both the virtual and in-person attendees For those of you in the room Here you may have scanned the QR code from the displays out in the foyer But if not, please take a moment and scan the QR code. You'll see up on the screen You'll then be redirected to the specific session page for Q&A For those of you joining virtually once you've logged on to the virtual conference platform and join the session There was a tab for electronic Q&A. So I have four speakers with me today on the panel The first speaker will be John Wise Dr. Wise is a senior technical advisor in the NRC division of new and renewed licenses He supports the resolution of technical and regulatory issues on a broad variety of materials topics with particular emphasis on long-term plant operation and aging management His career at the NRC has also included positions as a materials technical reviewer for reactors and spent fuel storage and transportation systems Prior to joining the NRC, John held metallurgical engineering positions in the steelmaking industry and in failure analysis consulting He's a graduate of Michigan Tech and Northwestern universities Our second speaker will be Flavien Simone. Mr. Simone studied mathematics and fundamental physics at A. Cole Polytechnic in France after graduating from this school. He decided to join the French civil administration He first became chief of a risk prevention department and a French regional administration His team being responsible for the control of the hazards caused by industrial activities and their impact on the environment He then joined the French nuclear safety authority ASN Becoming the deputy director and later the director of the pressure vessels division in this division They oversee the control of all matters related to the design Manufacturing and operation of pressure vessels and piping and civil nuclear sites in the recent years They've been particularly involved in the control of the manufacturing of the equipment of the EPR and EPR 2 types of reactors The stress corrosion cracking issue and the aging of reactor pressure vessels and cast stainless steel components Our third speaker will be Miss Heraku Sasaki Miss Sasaki is currently a deputy director for planning and coordination in the regulatory standard in a research division in the NRA in Japan She has been with the agency for 10 years and supports the technical evaluations of the codes and standards and Coordinates the public meetings related to the various technical issues She was a vice chair of the codes and standards working group of MDEP and a member of the working group on codes and standards of the CNRA Our last speaker will be Jin Ho Lee Dr. Lee serves as a senior advisor at KENS the Korea Institute of Nuclear Safety He joined KENS in 2000 and has held various Key management and leadership positions including executive vice president from 2018 to 2021 and director of safety research division He also served as the heads of four different departments including international project management international cooperation Mechanical and materials engineering and legal affairs and safety standards For 12 months starting in May 2004. He visited the Argonne National Lab and performed joint research on steam generator tube integrity Dr. Lee served as a member of the IEA Commission on Safety Standards a nuclear safety standards committee from 2018 to 2023 before joining KENS. He served in the military as a professor in mechanical engineering department of the Korea military Academy He received bachelor's master's in doctoral degrees in mechanical engineering from Sun Q Kwan University in the Republic of Korea All right. Our first speaker today will be John Wise The topic of managing selective leaching during long-term operation Thank You Brian. Good morning This morning. I'm going to explain the NRC's approach to Addressing emergent aging issues in long-term operation and as Brian Outlined in one of his first slides the idea is to walk through this a case studies It's what I'm going to do this morning is I'm going to use selective leaching the aging mechanism as an example of Of how we work through an immersion aging issue, you know, this thing So I'll talk a little bit about the background of this particular aging mechanism, but then Discuss how the NRC, you know, takes such an issue to evaluate it assess its implications for the wider industry And then make decisions about whether or not that Experience needs to be shared more broadly or or whether our regulatory programs need to be adjusted So first just a couple of minutes on selective leaching to bring everybody up to speed on this aging mechanism this is a Generic term. It's often it goes by many other names as well. It's very frequently referred to as the alloying There are also very specific terms that Are used when you're talking about a particular material usually in the in the case of cast iron just to be called Graphic corrosion and you can see the other terms. They're listed The illumination for example for copper based alloys but what all of these Mechanisms have in common regardless of the material is a feature that it represents a corrosion mechanism where Basically, you have a galvanic cell where one part of the microstructure acts as a Sacrificial anode to the other part of the microstructure and so if you look at that example of cast iron and that Graphic on the bottom In that case the the iron matrix of cast iron sacrifices itself for the graphite flakes in the microstructure and so in the case of Cast iron in particular what makes us a particularly challenging degradation mechanisms is a couple of things first of all It can take a long time to show up so you may have decades even of experience and and without any any Indication that anything is happening, but then it emerges later on after many years and so Recognizing that and and planning for that in our aging management strategy is always something we have to take and keep in mind and the other part about this mechanism and again in the particular case of cast iron is You can you can get a significant Loss in the structural integrity of a component without any really any visual indication that that has happened in that picture there you see a I took that picture and it's a it's a it's of a cast iron pipe and municipal gas main and I can tell you that there you can see the rupture there and the pipe itself essentially lost all structural integrity It didn't have any toughness but looking at putting your hand on that pipe And even wrapping on it with your hand you'd think it was a solid pipe But in fact most of the iron matrix in that cast iron had been converted iron oxide And it really didn't have any structural integrity and that makes it a particularly hard Aging mechanism to to to manage just just given that lack of visual indication Next slide, please. Oh, sorry. I'm I've got to tell myself the next slide Come on Brian So yeah, so Just very briefly we've had Here's some some examples of operating experience over the years Associated with this particular aging mechanism in the United States the experience tends to be Associated with cast irons, but you see aluminum bronze is Also one of the materials that this occurs in we've had experience in in that particular case the the aluminum is lost in the material Due to the selective leaching mechanism and I'm My intent isn't to go through one by one But just recognize that you know, we've experienced seen seen instances of selective leaching over the years and in those cases where we felt that the the the experience was Warranted a broader communication. You will see those note those indications of an Information notice or IN numbers at the bottom and that that's those are cases where we felt that the experience was Significant enough that we as a regulator felt that we needed to issue a communication to the broader industry for their awareness and Finally on the far right-hand side We talk about the experience in the nuclear industry, but it's really the non nuclear operating experience in many cases is the most telling and most helpful for us to learn about this aging mechanism because the Selectively sham cast irons in water distribution systems in the United States particularly the East Coast cities have some really old Cast iron piping systems. They provide a lot of information that we use to inform how we address selective leaching in the nuclear area So as as with all instances of operating experience The NRC through its operating experience program Goes through a number of steps, you know, we collect the operating experience We review it assess the implications the safety significance Applicability to whether the operating experience is unique to the plant or applicable to the wider industry And then we need to make a decision as a regulator whether we feel that there is a need to broadly communicate this experience to the broader industry and whether or not our own Regulatory programs need to be adjusted. So typically what's happened in the case of the selective leaching mechanism We've obviously case-by-case, you know, our our inspectors in the regions and I'll handle the plant-specific issue in particular But generically we we've assessed that information and as I showed in the prior slides We've issued communications to the industry when we felt that it needed to be broadcast And we generally have used these information notices and that's just one of our communication vehicles that You know push the information out to the industry with the expectation that each plant will take that information and themselves evaluate it and consider whether or not it needs to Lead to specific actions at their plants and we have different types of communications That we use information notices are one, but the different types of communications vary by The type of information we wish to communicate and the expected actions of the plant And finally the bullet down at the bottom is really what we're talking about a great deal today is long-term operation And when we when we talk about long-term operation We're usually talking about aging management programs And so we look at this operating experience to determine whether or not our own guidance for aging management needs to be revised And so and that indeed has happened I don't want to get into all the details of this of this slide But just broadly we have our generic aging lessons learned report which provides example acceptable approaches to manage aging and we have a program that we provide in our gall report and That program has been has evolved over the years as we've learned more about this particular aging mechanism The blue boxes represent our initial license renewal or 40 to 60 year guidance the orange yellow box is our subsequent license renewal guidance for 60 to 80 years and As you can see early on this program was One-time inspection you did once when you entered year 40 of you know 40 plus at your plant You selected a sample of components at your plant to determine whether or not really to verify that this wasn't an issue at your plant that is the program and You can see there's it had a combination of visual inspections But as we already discussed you need to do some sort of mechanical inspections as well to really understand the structural component of this aging mechanism But what we've learned and what you've seen at the at the prior slides was We're kind of beyond in many materials just Verifying that selective leaching isn't happening because in many cases for particular materials in particular environments We know it is happening And so over the years and as you go to the right-hand side of the page Our aging management approach has moved from a one-time inspection to verify It's not happening to periodic inspections now where we're really managing an aging mechanism in many cases We expect to happen for specific materials and environments but that's that's our generic guidance and plant-by-plant there may very well be plant-specific considerations where that generic guidance doesn't work and so in the end and so in this particular case study I'm showing here in this slide was a plant that was coming in for initial renewal 40 to 60 years They had a significant history of selective leaching of aluminum bronze and you can see the huge population of castings and welds that were Considered susceptible to this aging mechanism And as I said in my prior slide the 40 to 60 year recommended program was really just a one-time inspection to verify That's not happening. Obviously, that's not appropriate in this particular case because it was happening and so in this particular case the the NRC staff had to work with the applicant to come up with a program To address the fact that it's it is happening and there's a very large population and this included as you can see a whole host of Approach is taken from visual inspections on most on a large population components to more intensive investigations destructive ultrasonic on a smaller sample size and so this represents a case which you know happens occasionally where You know our own recommendation generic recommendation just isn't appropriate and in this case We'll work with the applicant to to figure out the appropriate approach going forward So broadly just the takeaways You know the NRC we provide, you know, we've used operating experience to refine our Recommended aging management approach and it has evolved over the years to become stronger particularly in the cases where Aging degradation is expected But plant-specific approaches Often will still need to be used Ongoing activities as Brian mentioned and in his opening We are currently have a few revisions to this particular aging management program in our in our gall report guidance. That's That's drafts that we're evaluating the comments right now and that includes a couple of Smaller adjustments to the program to take into account new information that we've learned and and secondly We have had discussions with the industry particular NEI about Potential taking a different look at this program where risk information might be brought into consideration to perhaps Focus resources, I guess I'll say on those areas that are most risk-significant and that's a that's an ongoing Conversation we've been having with the industry for the last few years and and so that will continue and so with that that's it for me and Thank you for your attention and I'll turn it over to Flavian. Thank you so good morning the the topic I'm going to talk about is the Degredations we faced in France on some cast stainless steel elbows of our main coolant lines so Yeah, if I go over here on our oldest type of reactors which some of you may know our Similar design as some Westinghouse Power plant designs pressurized water reactors that they are we have some elbows that are Outlined in in blue in the figure that were made of cast stainless steel in in the 70s and in the 80s and some of them were made in a particular steel with High molybden content that is particularly subject to some thermal thermal edging mechanism And The phenomenon is called thermal Umbritlement and it is because this type of steel Which is a duplex still is made of two phases one is a Nostenitic phase the other being a ferritic phase and The ferritic phase is subject to Umbritlement under the influence of the temperature the plant is facing during the normal operating conditions there is a in fact the composition of this ferritic phase in two phases and Basically and the impact of this decomposition is that the the mechanical behavior is modified and the toughness is dramatically reduced over time because of this Umbritlement and so the the rate at which it occurs is depending Obviously on the temperature of the plant but also it's depending on the concentration of some of the Chemical elements within the steel such as a chromium molybden or seletium There are the elements that have an impact And as you see on the right I displayed the impact on a sharpie impact strength and the values are evolving Up to a lower bound value that is rich for Normal or temperature conditions after maybe a hundred thousand hours of operation maybe two hundred thousand hours, that is the order of magnitude and If and I gave you also the some toughness values that were measured in the 80s on some aged material some material that was aged in laboratory and These were as low as 20 to 30 kilojoule per square meter, which is obviously very low and the the toughness that we expect for Currently the EPR reactors on the main coolant lines. It's above a hundred kilojoule per square meter on the wells and it's even more for the base material and The other issue was that in the 80s There were some big flows that were detected on the castel balls of the the main coolant lines there is a Picture on the right showing one of those flows that was discovered by a from at home in the 80s and The the problem with these flows was that they were not found during the Non-destructive examinations that were conducted by the manufacturer. They were found By EDF just before the start of the of those plants so it raised a concern for the ISN because We were knowing that the the material was subject to a degradation that was impacting its toughness a lot and that There could be a risk of some flows That were not discovered by the manufacturer and kept within the material So the the action of the ISN at that time was to ask our licensee or the F2 Assess the impact that it could have on the structural integrity of those elbows and by doing some fracture mechanics computations And the first approach was a very conservative because we asked them to study the impact of What was called the reference flow and the dimensions of these flows would be a And I mentioned that would cover the size of the biggest flow that was detected in the 80s on the elbows and The at that time the the toughness values they were They were determined using some first formulas that were designed by EDF in order to try to predict the effect of embrittlement and the conclusions at that time was that An operating period of more than 10 years was justified But obviously this is way lower than The the amount of years we operated the reactor the reactors now. So there are some further studies that were done and There were two things that were assessed by the the ISN in the 90s first Considering the the flow that needed to be considered in those fracture mechanics computations we accepted to reduce the size of This so-called the reference flow and the main reason behind that is that The flows we can expect in a cast material are not as harmful as for example a fatigue crack The fatigue cracks that are used when determining the toughness of a given material So we accepted to use a reference flow that was in fact smaller in dimension that Than the the the flows that were observed in some of these elbows and The the other aspect was that I said asked EDF to Improve the way fracture toughness was predicted under the effect of embrittlement So I gave in the presentation some examples of the formulas that were used in the 1990s There were the rift from test material mostly Tests that were performed on some aged material material that was aged in in the laboratory at different temperatures and for different aging times and The the principle behind those formulas being that EDF could predict some values for sharpie impact strength And then using some empirical correlation Try to predict the toughness of the material based on the predictions on the impact strength So that was the the the initial approach in the 80s and in the 90s The issue with that approach is was that the formulas that were used at that time they were not taking into account test material that was representative enough for long term operation and In the 2000 and 2010 we we had reactors that were reaching 30 and even 40 years of operation and The question raised by I said was okay. Can we Reliable predict the toughness of those materials up to maybe 60 years of operation because we were starting to think about about those those the 60 years of operation for for the French fleet and so I said asked EDF to launch a very important program in fact to to try to To revise those toughness provision formulas to update them taking into account Those extended time frames for for operation there. So so they they conducted some tests on more than about 600 materials, I mean Samples of materials that were either harvested from some elbows that were in operation or also some Did they use that some some material from the manufacturer that was aged in the lab and So with this bigger database they updated the formulas taking into account a lot of input parameters One being ferrite content because the ferrite content in the steel is impacting a lot the final toughness but also the concentration of Many chemical materials that was available from the manufacturer and so currently we have formulas that take into account all this manufacturing data and that is at least supposed to predict the fracture toughness with a coverage of more than 80 percent of the test results this value of 80 84 percent being the result of The statistical approach we use in our fracture mechanics computations So at that time I said did it's on assessment using the test material that was provided by EDF Comparing it to the results of those formulas to check that in fact we were indeed covering more than 84 percent of the results. So the results were quite Satisfactory the database was also covering some samples that were aged up to 200,000 hours which was Enough to cover up to 60 years of operation and so With that there were some new fracture mechanics computations that were performed and That showed that the Most of the elbows that are on the hot leg that are the ones that are subject to the highest temperature could be operated up to 60 years of operation And the same demonstrations were done on the other elbows that are exposed to colder temperatures and most of them were also Justified the issue being that some elbows with the highest ferrite content could not pass those fracture mechanic tests and therefore should be replaced before this 60 years time frame This is the current the highest current concern for the ISN because some of these elbows are not easy to replace Especially the ones that are directly welded to the RPV due to hide those constraints And so our current perspectives on that is first to study the opportunity to replace some of these elbows It is kind of easy. I mean it's never easy But kind of easy to do for some of them that are not close to the RPV It's way more complicated to do on the other case so that's something EDF and we agree on that doesn't really want to to do So the other perspective is to improve the way we inspect those elbows to make sure that there are no flaws that would Frighten their structural integrity even though the toughness is low if you don't have big flaws The issue is not as high The problem being that it's not easy to inspect cast stainless steel because of the the structure for example UT waves Penetration is not very good So there is currently some research to try to develop some process that would at least be good to inspect the first 10 to maybe 20 millimeters from the inner wall because that is the part that is subject to the highest stresses for example during a locate accident and other perspectives being Being reviewed at the moment by EDF and the ISN are Using some new fracture mechanics hypothesis that would be less conservative that would Take into account in a more precise way the the constraints that are generated by those flaws and Indeed at the moment we are only using some toughness values that are determined on some standard test samples that are in fact assessing the toughness when you have a crack We know that The type of flaws that we have on cast stainless steel are not as harmful as cracks But it's very difficult to know what is the precise difference and how to quantify it So this is some ongoing research at the moment. I send still asked for some conservative fracture mechanics assessment This is one perspective also So just to say that this in order to wrap this up This is not a new Degradation issue that we are facing in fact we were aware of it since the 1980s But the longer you operate the plants and the more difficult it is to justify that you still have some margins In the case of a degradation that that is slowly Decreasing the toughness of your materials. So the longer we operate and the more precise the the justification or methods have to be and this is the The goal of ISN is to make sure that Even if you get into more precise physical models Fractal mechanic methods you still conservative enough in order to to maintain a high enough safety I mean safe enough operating conditions And I think that's it. So thank you for your attention So good morning. Good morning everyone My talk has two kind of topics The first one is the current regulation revision in Japan and the second one is recent topics related to long-term operation Before Fukushima accident, there is no limitation of operation period but after after Fukushima accident Japanese government defined the limitation as 40 years originally and Could be added maximum 20 years by another approval However 13 years passed from a kushima accident only 12 nuclear PWR nuclear power plant plants operating and Some PWR plant and every PWR plant has been stopped during more than 10 years So Japanese government made the new policy and The act related to reactor nuclear reactor was revised last year current regulation period as mentioned before and after 2025 new operation period will be started and the new operation period Operation suspended period can be added after 60 years So operation suspended period means the period of conformance review of NRA mainly and operation period will be reviewed and approval of the Ministry of economy trade and industry Of course new system for aging management will be done by NRA as similar as before Next is operating experience What's case is steam generator tube cracking at Takahama unit 3 The tube material is TT 600 alloy and there are two kind of technical issue first one is PW SCC in early 2000 PW SCC's were found in 21 tubes and the licensee conducted short peening for the for residual stress relaxation During 10 years, there is no there was no indication. It's good but during our next 10 years PW SCC were found in four tubes and the last year more one tube licensees investigate the cause and estimate that Compressive stress was given to 0.2 millimeter depths in 2020's short peening But estimated that SCC which had reached deeper than 0.2 millimeter has propagated and second issue is sinning in 2018's and 2020 Sinning due to repeated contact of a falling object and repeated contact of tube and the tube were found and In 2022 erosion by scale was found the scale came from water supply and Dicency cleaned up of the tube to reduce the falling material Reduce scale and Maintain high pH of the water supply to prevent a new scale but however in 2023 erosion by scale Was found again Currently kept go plan to replace of the of CSD Next one is ID SCC in PWR primary stainless steel piping at OE unit 3 in 2020 Significant indication was found in the on the surface of the pipe This is a photograph of the cross section of the clock besides was 3.6 millimeter depth and 6 millimeter length So it's very big clock for us and we were very surprised and licensee investigator calls and estimate that the calls was excessive welding heat input and Surface of the pipe was hardened And the crack was occured and propagated sorry in this case in further investigation is conducting now and We another a here from the licensee the result of the Investigation every year So one is the reactor shut down due to rapid decrease of PR neutron flux at Takahama unit 4 Last year the reactor suddenly shut down and Licensee found that sorry Okay connect cables Sorry cables put on the the other cables and Cables sorry cables a pool and soldering peeled off and Cables disconnected Of course this case is No performance of the construction, but why now it takes more than 30 years from construction So we think there is possibility of the degradation of the material such as soldering And the licensee will conduct the investigation of the Penetration after replacement First case is transformer damaged by not open insular earthquake in 2024 On July this first this year earthquake has occurred it was many magnitude 7.6 and The seeker nuclear power plant is located in the not open insular and In the plant to transformer Was or are damaged by the earthquake and Sorry Connective pipe was damaged and insulation oil leaked from the Transformer this is a photograph at the time these transformers were Designed as a seismic class C component according to Japan Electric Association guide Sysmic class C is almost same as commercial grade But Japan Electric Association calls require you to register the 500 to go earthquake There is no measurement device around the transformers So Hockrick electric power company is now Simulating the in the earthquake intensity to investigate the cause of the leak oil leak including these cases Operating its experience is reported to the NRA Committee meeting it is held once a week and Regulatory implementation plan is approved by NRA Sometimes further investigation will planned by licensee and Further investigation result is sometimes reported to a directory NRA committee meeting or sometimes reported to Technical information review meeting and regulatory action is discussed This is final page of my presentation and this is my salt and Maybe question So based on my experience, what is a better method to correct important information? We collect information internationally from the other countries regulatory body and international organization But some important operating experience were not found from the information But provided from international working group Such as codep I think it means that they are Correcting collecting information method is not adequate In fact, I myself is a member of the correcting information team. So maybe my fault and the second is Second is Related to language barrier and other emphasizes transparency and openness and the licensee this close a lot of information information Including data photograph figures But most of the materials are written in Japanese and it is difficult to provide to the other countries third one is Related to traditional understanding recent topics shows us that Sometime it is necessary to reconsider the traditional understanding So This conference is very good opportunity for me to to share our experience and I hope you get provide me a Good idea or good salt Related to these Salt and the question. Thank you so much I'm very pleased to share current experience on aging degradation in Korea or with you As a rule March 2024 Two nuclear power plants were permanently shut down in Korea and the five units are under construction and 24 units 25 units are in operation the average operating year is 24 years seven of them is Operating operating or more than 36 years This indicated that aging management is becoming more and more important in Korea The offers a table Shows the status of performance to shut down in Korea Korea unit one or worse Operated for 10 years beyond its design life and Wilson unit one was operated for less than 10 years Beyond is the design life in any case they were permanently shut down for Political reason not safety reasons after changes in energy policy for continued operation Seven nuclear power plants applied for continued operation these days And it is expected that 10 to 12 nuclear power plants will apply for continued operation by 2030 this slide shows a regulatory Framework for continued operation in Korea the continued operation System was introduced under the framework of PSR periodic safety review With reference to the US license in your rule the PSR system and the continued operating System was were introduced in 2001 and 2005 respectively in PSR system as you know The safety assessment should be Conducted at regular intervals Typically every 10 years under this framework The aging management to have to be implemented during the operation of a nuclear power plants as well as during the continued operation beyond its design life In this respect, I think that I can say that the aging management has become a living system in Korea in order to reflect Fukushima lessons learned from Fukushima accident the Korea regulatory body issued on administrative order requesting implementation of 50 Actual items one of the actual items is to develop and implement on Integrate the aging management program In a response to this order the Korean utility KHMP developed on Integrated the aging management program through that currently each nuclear power plant has one integrity AMP procedure and about 30 to 40 individual AMP procedures The licensee also developed the IT based the system called AMP implementation Implementation management system the Korea regulatory body approved the Integrated or AMP and inspects is the implication implementation status and the results during every period inspection this slide showed the conceptual diagram of the IT based the AMP implement implementation management system So far I introduced the briefly the Korean regulatory Framework for continued operation now I'd like to introduce recent aging issues the first one is Requees in inco-instrument guide tubes As three nuclear power plants in operation for more than 30 years Requees have been found during their planned Ovalism. Reques were confirmed in the ISRI tubes and they were Detected in the form of a bollig-Hedge of respiration bollig-Hedge deposit were found in one Cobb the section and found in several horizontal joint areas of ISI guide tubes Through root cause analysis, it was found that the high chlorine chlorine content rubricant was used during Seal table maintenance in the past The concentration of chlorine ions was intensified due to stagnation of the high temperature reactor current and it is thought that this Created the cause of the environment in addition microstructure analysis showed the non-metallic Inclusion such as silicon carbide it was found that The these non-metallic inclusions were introduced during the many manufacturing process From this it can be concluded that the root cause of ISI guide tube requies is 15 corrosion due to Corrosable water chemistry and the non-metallic inclusions there are measures such as chemical analysis at all nuclear power plants and Reduction of Inflammatory concentration through gravity Duration and direct to visual inspection have been Taken as corrective actions in addition the previous The existing AMP was improved by conducting effective BH4 gas the corrosion program and by adding local water chemistry analysis The second recent aging issue is the request from swing checkable hinge in February 2023 or steam Rick was identified from the hinge part of the safety injection line swing checkable over Nuclear power plant that had been in operation for more than 22 years and left left picture shows RCS wine safety injection wine and the check valve Steam Rick's and the corrects were found in the Belved body near hinge The slow root cause analysis it was found that corrosive Environmental was created due to ionized ionized the lubricant and Stagrant reactor current between the body and the retainer in addition It is thought to that excessive torque was applied because no specific torque value Was not provided in the many picture approaches in the past It is thought to that the high stress was caused by Facialine retainer and the flog bolt with the excessive torque Through this it It was concluded that the root cause of Rikuzi is TG SSC trans-cranial stress corrosion cracking caused by stress and the corrosive environment term registers such as a visual inspection using high resolution Indoor school camera and Shorten the monitoring cycle have been taken as Corrective actions also as some Improvement of the design and And To you to eliminate the brand spot through the design improvement was also taken As a concrete remarks I would like to mention lessons learned from recent aging issues aging management management should be a living program Proactable measures should be taken to eliminate the brand spots Operating experiences should be Reflected into the aging management, you know timely manner to meet the moment Air process should be made to utilize today's innovative and Clip edge technologies There and also the mindset should be changed at the same time Thank you for your attention Thank you panelists for the the nice presentations I think there was kind of a common theme throughout all of those is that each of the agencies appears to be like Learning over time evaluating operational experience and then adjusting their guidance and requirements over time To reflect that what they've learned as well as working with licensees to address site specific issues. So All right, we have plenty of time for Q&A. So please submit your questions. We do have a few Pre-written questions here that we want to go through some of those first before we get into some of the audience Q&A And so the first question most will try to ask a to the panelists to address is When a new or unexpected aging issue arises at a plant in your country What is the role of the regulator in assessing its implications for the entire industry and what is the role of the plant or industry? John do you want to go first? Sure, and I Guess I'll be brief because I think I'm going to expand on just some of the same themes as I went through in my presentation, but you know the NRC has a you know an operating experience program and we have An internal instruction that guides that program and for those that want to look it up. It's LIC 401 I believe lick 401 and It's available publicly and what about that program does is it basically describes the process by which the NRC collects evaluates screens the safety significance of issues and and ultimately Identifies actions and those actions could be anything from as in the case of my presentation Simply issuing communications to the industry To ensure that they are aware of the issue and they can apply that experience as appropriate at their plant But the actions could also become something more broadly than that for example Very time-sensitive high-safety issues there could be a regulatory action Something as extreme as say in order where there's an expectation to plant take in an immediate action But but longer term the same process. I'm describing our operating experience review process Directs us to look at our broader programs The does that operating experience cause us to revise our should cause us to revise our guidance or is rule change in a rule Justified or change in our inspection program or or even longer term change in our research program And so by this process, you know again, we call it the lick 401 or LIC 401 process It kind of guides the staff through all of those steps and But outside the NRC, you know, we have there is the plants in some sense do the same thing, right and and The plants have there there is you know requirements that plants evaluate operating experience and But on in their part when they experience operating experience The expectation is that they themselves also make that decision whether or not that experience needs to be shared with the broader broader Community and they do that principally as as most of us know the the different programs that are involved Such as the input program to share operating experience outside of your plant as appropriate And so as part of our licensure in the world review We actually do take a look at that program from the aging management perspective directs the staff to look at the Applicants process just to ensure that long-term aging issues to our evaluated And as appropriate, you know, not only evaluate for at their plant that experience But but also pushing that experience out to the broader industry With that, I guess I'll just turn it over to any of my other panelists So first there is something in particular in France because we have 56 operating reactors, but we only have one licensee So this makes the landscape a bit different from what it is for example for an RC or other other regulatory bodies So the discussions will be one to one one to one between our licensee and the ISN and The I would say that the licensee's responsibility would be to to take actions in order to to assess the issue First to understand its causes then its implications on the safety of its plants and after that to take the correct mitigation actions and the role of the ISN would be to make sure that these actions are appropriate and If not to make the licensee take the the appropriate actions so Maybe it's a bit simplified to what you have to do in order to I would share the information That occurs on a particular plan to the other licenses Of course the licensee and the industry Required to investigate the root the cause But NRA is very active and play a good role to in an assessment to identify the safety impact and if the ISN issue is Very important to safety NRA will use the backfitting system because we have backfitting system and Revised the requirement and after that licensee have to Arrow the new requirement and the recent recently Atomic energy agency Athena Sometimes had actual action to in response to regulatory requirement regulatory request or Expectation from the NRA. So this is a recent Activity from the industry. I think in Korea and the world Typical and role and the approach of regulatory is almost the same It is they are their role is to make the utility Investigated similar cases of home and the world identified as in aging management mechanisms Inspect are other related nuclear power plants and take corrective actions The typical role of the licensee and the industry is to take other necessary measures and to Disseminated the operating experience at home and the world However, when are new and unexpected aging issues arise It is not easy to Find the root cause in a short Time short period of time Therefore, I think that it is important to regulator for regularities and opportunity to conduct R&D Appropriate to their respective roles and in parallel with this I think it is necessary to continuously find and the remaining to find the spots through mid and long term R&D So another question that I think most of us on the panel here might be able to answer is as nuclear power plants operate for Longer periods. What challenges do you see in preparing for and mitigating new or more significant aging mechanisms? Start with Lavin One of the biggest challenges and it may also be particular to France is that we have a standardized type of reactors so there is always the possibility of an aging mechanism appearing and Quickly impacting a lot of reactors and therefore threatening the the electrical power supply Which obviously makes things a bit more difficult even if the regulator is not directly concerned with energy production So I think this raises the importance of Inspection in order to detect the more quickly in the more reactive way those new aging mechanism It is very important to to be able to to detect them quickly in order to take reactive actions and For that I think we need first obviously to take into account French operating experience But also international experience as you have pointed out in your presentations I think this is very important. We may not always be reactive enough to share some information You raised the CC And another important thing is that there will always be Some things we can predict but there will also sometimes be some things we were not able to predict and What we faced in France with the discovery of SCC impacting a lot of reactors sometimes with a high number of cracks affecting some safety significant pipes It was completely Unpredicted and so our inspections there also have to to take some To take into account the risk of finding something in some systems that are not believed to be impacted by some non degradations, so I think then the challenge would be to To have the appropriate inspections done on the risk On the parts that are concerned minus some risk but also to To have a few inspections the right amount of its inspections on some other parts of the plants So my thought is similar to Flavien. I Think it's very difficult to find the unknown technical issue Important is important operating experience and sometimes came from the in service inspection but It is may necessary to reconsider the traditional inspection program because They as I don't know that that is Appropriate to the LDO so I think the Safety research is important to that take in the day or in the account and We and NRA It has many kind of Safety research. I think it is very effective to find the unknown technical issue In Korea the situation is different from other countries in that Nuclear power plants are Continuously being built However, this is not only has the advantage but also this have this advantage recently in Korea applicants application for consular permit operating license life extension and Ten year PSRs have been rusting together To focus on safety significant issues including new or more significant aging Mechanisms we needed to establish is trim land and the more efficient the process I think that this is the most challenging one in terms of the review process In the technical Perspective, I think that the most challenging one is to Identify an unknown aging mechanism in our timely manner This is because unknown aging phenomena Continue to appear even though a large amount of data is accumulated So I was just going to expand because I think you've seen some common themes here This this idea that we don't know everything and how do you how do you? develop an inspection program when unknown when unknowns may or are very likely to emerge and So we talked about some different aging mechanisms that were brought up in this panel today that emerge after quite some time and so if if a You know you were all we're all Always looking to be more efficient in our inspections and as as in regulators were often presented with Proposals to take a you know more risk-informed approach to our inspections, you know don't look at the Spent so much time looking at the components where where the past Evidence of failures just isn't there for example, but what that what that what the struggle of the regulator is is You know, how do you handle the unknowns correct as well as the fact that you know some of our Components have a very good operating history with no failures because because There was a very rigorous inspection program in place so if you have a very rigorous inspection program for example an as me code program that Looks for evidence of degradation and directs, you know repairs in a timely manner You simply may not have a population of components that have experienced the failure And that can that can be challenging because that doesn't show up as a high PRA number for example as a susceptibility risk and so as a regulator we when we presented with Proposals for again making more targeted or efficient use of inspections. We always have to sort of keep these things in mind And that's a challenge Thanks for those responses so so multiple panelists here have mentioned risk just in that response And risk and being risk informed and using risk insights has been discussed a lot in this Rick and and for Many years sit back as well. We've gotten a couple of questions related to risk from the audience So long-term operation a lot of times focuses on passive components How how can we? incorporate risk into Licensed renewal or long-term operation and aging management programs. Is there anything going on there? I know John you're actively in the middle of evaluating how to use risk Yes, so I guess I'll At the NRC we're kind of Addressing risk in a cup thinking of a risk in a couple of different manners at this at this time We're thinking about risk in terms of We can use risk information to determine just how Thorough I guess I'll say or deep of a review the regulator does like how In depth to our own regulatory reviews need to do to be for those systems that may be more or less risk Significant and that's an ongoing discussion. We're having with the industry now and and we are adjusting our processes right now to try to You know tailor the level or depth of our renewal reviews based upon the risk significance of systems But it's but on the other side another way of thinking about risk is just as I discussed in the previous Response using risk information to actually shape an aging management program how many inspections you need to do how frequently you need to do it and And so and you know, I won't be labor it because I discussed it previously But we're just the challenges of applying risk to a passive component that may have been very reliable over the years and using risk numbers to Project future failures of such components can be can be difficult, especially when you're talking about very long-term operations But again, this is something that the in the US the regulators act actively You know are discussing these issues with the industry. So stay tuned. We'll see what happens Turned over Are you're considering risk in your activities? You don't have to answer Maybe some something on which I can elaborate from John's Answer is that of course we need to know what are the actions taken when there is a risk that is known and if they are appropriate but On components that are not subject to any known risk We still need to know what will the licensee do and maybe one of the precise things to to look at is what is the sampling rate of Inspection programs that are planned for those type of components. I know there are some Rules in some of the codes as may have some basic sampling rates In France, we don't have those Which means that When you're not doing an inspection program on and we on a risk-informed base You don't have any reference at all to assess the proper sampling rate And I think this is something we need to think about in the next years Because it's quite a concern for me to have a big sometimes important parts of our plants which are safety significant And which are not undergoing any inspection at all To determine what would be a good sampling rate in the future. All right, so we had another question come in I Know this it's addressed to to Jinho, but I thank her a coup You mentioned this as well, but in your remarks you mentioned utilization of artificial intelligence and aging management Can you elaborate on the potential and possible app applications of it? that I Strict speaking I have no Specific idea about that, but I think that we can Get obtencent marine ideas from the today's technology point or there are several examples in the case of the ISI in-service inspections most the case is that the UT technology is being used The conventional one is using the angle beam Proofs, but nowadays that the phased array proves are being Used widely in other industrial side Does I think that those kinds of technology can be used in the nuclear fields? another one is to using and Comfort wise data analysis in the case of easy to At the current method it produces lots of large amount of Signals and data signals if we use the neural network and AI Dance we can Performs more effective inspection And another better challenge one is to using and AI pattern recognition recognition technology The high-resolution cameras are being developed to quite well these These ways if we use the pattern recognition recognition technology using The AI dance so we can find more more floors in Inside the Reactor fresh vessel that the kinds of things could be a good example Thank you Eric you did you have any ideas on yeah, no Yeah, something to share but I even though I'm not I specialist at all so take what I think with a pinch of salt But as I think that the principle being IA is to educate some Model on some data. I'm not very sure that it's good to predict the in predicted If you don't have any sign at all if you the data you you got I'm not sure IA will predict that There will be a CC on stainless steel in the next years for example so I think we need to be as regulators careful about the design of some Inspection or aging management programs that would be only based on IA predictions Okay, thank you We just started to learning about the new technology and We are correcting the information from the other countries Okay, okay stage. Okay? Okay a question for you Heracu Was there any consideration for aging that occurred during the 10-year shutdown or because the plants were not operating Was that time assumed to have no deleterious effects? It's a difficult question You what do you mean is Impact to the industry from a yes from like an aging standpoint of the plant Was there anything specific you considered regarding the time that it was shut down? Yes, and this is my opinion Recences in confusion just now and They trying to do something to put for example technical research safety researchers trying to use Risk information method to to explain about the Conformity of the liquid requirement, but just now balance between industry and regulatory body is very Not equivalent because let's see wants to start the plant, but We have very strong deterministic liquid requirement. So I don't know how Situation but it's very difficult to Explain about the story Okay. All right We talked about operational experience a good bit up here and the evaluation of that and so So given the implication the world-wide implications of aging management How do you incorporate international operating experience? into your guidance And how do you share? Operational experience with our international counterparts John you want to I'll just kick this off So a few a few mechanisms first first of all, I know there are you know international operating experience databases that we certainly can pull from but I guess I would say is one of our I think one of the most powerful means of Utilizing international experience is some of the activities that Brian mentioned at the very beginning of the kickoff of this of this Session which is developing relationships with our fellow regulators and and and international plants Through cooperative White, you know, wide cooperative efforts like the IE I Igal program for example as well as One-on-one, you know, we is very common for us to you know Meet in these large cooperative groups, but we we regularly meet with both foreign regulators and foreign plants It's very frequent and it's to talk about long-term aging issues And Brian mentioned just a few of the interactions with with the countries that are here on the on the panel And I think what is is most powerful about that is developing the personal relationships Because when something happens, and I'll just use an example of the French operating experience where they're cracking You know, what was our initial reaction to that? Well, that was to have our senior technical advisor Dave Ruddling get on the phone and say Dave call all your contacts in France and get all the information you can get and Why was how did Dave how is Dave able to do that? It was because of all the relationships that he developed through our interactions And that's that's made our participation in all the international groups, whether it's NEA IEA or others just really valuable Anybody else Totally agree your opinion In Japan important Operation experience came from the personal connection mainly so but we are collecting the Operating experience from the overall over the world and we make the Consideration or Resolution of the Technical issue to make Meeting material over the technical information review meeting. So and it provided to the licensee and this is she showed Meeting material and consider the their action and put into the PSR a safety review of the licensee so But it's very important to correct method is as mentioned before you as you Okay You know do you want answer or? In Korea, we are using money Operate of channels for the operating experience showing one of the Approaches to I using the through the IAIRS Systems instant reporting systems that is a multinational ensuring and information showing so the The other other one is the TRM between among the three countries in Asia Including the China, Japan and Korea. We are held holding TRM meetings every year through that in that one of the important to agenda of TRM is the Operating experience showing the through the channels. So we are showing our information and we are using and retro meetings one of the good examples is the cooperation between Korea and the UAE as you know Korea exported Nuclear propellants to UAE does repeatedly a showing information with them and we also Use using the our website Using our website all kinds of information is unordered if the foreign person are interested in our Information so you can visit our website and again can download or use for Informations, thank you All right All right. Well, thank you everyone. We're drawing to a close here I just want to thank my panelists for the wonderful presentations and the insightful responses to the questions So let's let's thank our panelists here. Thank you And thank you everyone and enjoy the ranger of the last day of the Rick