 Look at that. Okay. Well, it is 3.30. It is the appointed hour for our technical session on Reenvisioning the next generation of University-led nuclear innovation. So we're going to keep it going here on Einstein's birthday with and we're going to go deep on some pretty technical topics with these folks here this afternoon. When I came to the NRC in 2020, I had kind of three key focus areas. Accident-tolerant fuel, advanced reactors, and academic programs. And over, this is my third RIC, and I think now with this one, I have covered all three of those topics, and I'm happy to say that this is the one on academic programs and I'm absolutely thrilled to be here this afternoon to help facilitate the discussion among the participants. I'm going to make some opening remarks. Then we're going to have presentations. We'll have some questions after each presentation, and we've got time at the end. We'll have additional questions for the entire panel. So I am very excited about this session in particular because it highlights the bright ideas and research that's being done now that will shape the work we'll be doing in five years. I fully support the ongoing engagement with and encouragement of students to consider pursuing careers in public service or academic research, but public service. And during my tenure as commissioner and chair, I've had the opportunity. I've been able to visit a number of test and research reactors. In fact, earlier just this month I was at Kansas State to visit their little Trigamark II reactor that they're getting a tremendous amount of use of. And that's really one of the things for me is to be able to go to colleges and universities and see facilities large and small and not just reactors, but the additional other research capabilities and the things that are being accomplished is just amazing. In my tenure, I've also been able to visit MIT and Georgia Tech, Michigan, which doesn't have a reactor at all. I would add, as well as the University of Puerto Rico at Mike Wez. And although while not at the NRC, I was mentioning to our friends here from College Park, I've actually been to see the reactor down there as well. We've recently completed the third year of this program in our office of research. The research grants are highly competitive. We're excited at the overwhelming response we're getting to the research funding announcements. We've reviewed over 320 highly competitive proposals for fiscal years 2021 and 22 and awarded 46 grants. So you can see that's a that's a pretty low selection rate on the amount of interest that we're getting. Our annual notice of funding, a funding opportunity will be issued soon and we encourage institutions to submit projects that provide a variety of direct and indirect near and longer term benefits. And new this year, we will be considering non-technical research within an emphasis on environmental justice under this announcement. For example, work to promote dialogue that helps foster the development of innovative community ideas incorporates principles of equity and environmental justice into community engagement strategies. We also wanted to improve our participation with minority-serving academic institutions. So to encourage greater participation, the funding notice for research projects will encourage institutions to include partnerships with minority-serving institutions. Separate from the university-led grant program, we also have reinstated the minority-serving institution grant program. These grants complement our research portfolio in areas that we're working on here at the NRC and added benefit to these grants is that they directly engage students, university faculty, and nuclear-related programs in work of relevance to the agency and thus develop the next generation of engineers. Before we meet our panelists, I have a few housekeeping notes to share. I'd like to remind everyone to please silence your devices. For the Q&A session, your questions will be submitted through the electronic means, scan the QR code, and for those of you in the room here, again, the QR code, you'll need to log into the platform each day. For those joining virtually, once you're logged on to the virtual conference platform and join the session, there's a tab there apparently online for your electronic Q&A. Questions from both the online participants and those using the QR code will be added to the same queue, so everybody is on the on a level playing field and we'll get through as many questions as we can. So now I'd like to introduce our speakers for this afternoon's panel. Dr. Jessica Rojas is an associate professor in the Mechanical and Nuclear Engineering Department at Virginia Commonwealth University. Dr. Henry Spitz is a professor of Nuclear and Radiological Engineering at the University of Cincinnati College of Engineering and Applied Science. And with him is Jimmy Stringer, a PhD candidate also at the University of Cincinnati. Our third presenter is Dr. Michelle Shelby-Bensie, who is an assistant professor in the Department of Civil and Environmental Engineering at the University of Maryland. Dr. Bensie is joined by Joy Shen, a PhD candidate also at the University of Maryland. We'll hear from Dr. Jessica Rojas from Virginia Commonwealth University first. A little bit more about Dr. Rojas. She holds a B.S. in Engineering Physics and a Masters in Materials Engineering and Processes from the National University of Columbia and a Masters and PhD in Nuclear Engineering from Missouri University of Science and Technology, a University I might add well represented here at the NRC. Dr. Rojas' primary research interests include nuclear materials, radiation assisted chemistry and radiation processing. She has been actively working in accident-tolerant fuel cladding materials investigating their physical and chemical properties. Dr. Rojas' lab also focuses on radiation synthesis of nanomaterials, try saying that 10 times fast. Modification of nanomaterials properties through a radiation and development of multifunctional nanomaterials as radioisotope carriers. She is an active member of the Minerals, Metals and Materials Society and the American Nuclear Society. She has been chair and vice chair of the Virginia section of the ANS and she is currently serving on the ANS Board of Directors. The topic of her presentation today will be advanced characterization of ATF cladding for understanding their degradation under short-time temperature excursions and implications in dry storage. I'll now turn it over to Dr. Jessica Rojas. Okay, so first of all I would like to thank the NRC for having me here today to talk about the progress that we have done in our research project funded by the NRC program. So before I get started, I would like to always like to have this at the beginning just to acknowledge the team members. We have a multidisciplinary group in our Department of Mechanical and Nuclear Engineering Department where with different expertise that provide a nice combination for the work that we're doing in accidental nanomaterials. I also want to emphasize and acknowledge the wonderful students that we have in our program that have done this project in success. So the main motivation of our research project lies on the great advancement and progress on accidental nanomaterials to provide safety and improve the performance of a nuclear power plant. So, and this is to again provide a different alternative to circularly cladding materials. So the main technologies that we are focusing in this research project are, first of all, the circularly coated cladding with chromium and also the FICROL alloys APMT and C26M. I want to emphasize here that our project is being supported tremendously by GE Global Research and they are providing us guidance and technical support for the testing protocols that we are establishing in this project. So the main question of our work is how do these cladding concepts evolve at high temperatures. So I want to say here that thanks to the NRC we have been able to continue with this project that started about four years ago through an NEUP program, a grant that we had investigating the surface characteristics and the surface chemistry evolution of accident-tolerant fuel cladding materials at a high temperature. Specifically, we have been investigating a critical heat flux of these candidate materials. So then in this project, I have a couple of examples there from our previous work on CircularLog4 cold spray and PVD coated, chromium coated cladding materials. So we have obtained a huge amount of data in this previous project through the NEUP. So now with the NRC in particular, our goal is to investigate the oxidation and degradation of accident-tolerant fuel cladding materials in high temperature excursions, meaning under short time a heating rate and looking at quenching in the performance of these materials and their quenching. So we are interested on investigating the mechanical properties and overall performance of these materials under the given conditions. This project is also looking toward the dry storage conditions. So we are simulating hoop stresses and we are simulating a temperature profiles that are characteristic in dry storage conditions. And then finally, we are looking at implementing non-destructive examination techniques. In particular, here we are looking at a straight fluorescent spectroscopy as a way to determine or provide quality control strategies for coated cladding materials. So let me walk you briefly through the research objectives that we have in this project. So the first one is looking at the ATF cladding, a manufacturing and advanced characterization, looking at their properties and their surface characteristics. The second aim of this project has been looking at short time temperature excursions. So the first and second objective of this project, we have done a significant progress in particular at setting up the quenching facility. And rapid temperature excursions, a device. Then our third objective has been looking at simulating dry storage conditions and ductility studies. So for this particular objective, we are getting a substantial technical support from GE Global Research. And finally, we are looking at developing a straight fluorescent spectroscopy, a techniques as non-destructive examination tools. So these are the materials that we are investigating currently. So I have a few examples here in the pictures. You can see the current Circuloid form and chromium coated Circuloid Cladding material. We are looking at two different materials, the cold spray technique and the PVD technique. We are also looking at a Fickel alloys, both APMT and C26M. Now, these are all the variety of materials, advanced materials characterization techniques that we have in our university that is providing us with important information about these materials. In particular, we have a microscopy tools, a scanning electron microscopy and a transmission electron microscopy that allows us to look at microstructural features in the materials prior and after testing. So we are looking at micro and nanoscale features. We also have an x-ray diffraction to investigate the evolution of the microstructure as well. And finally, x-ray free electron spectroscopy, which we are using to investigate the surface evolution of the materials after the testing products. So just to give you a brief description of the materials that we are using. So I have a couple of pictures here for the chromium coated Circuloid 4. We are looking at in figure A, you see the chromium coated Circuloid 4 by a cold spray. So we see that this is a thick, relatively thick coating of about 20, 25 nanometers in thickness. In the other side, we have the PVD coated Circuloid 4. So just to give you a visual representation of the materials that we are investigating. And we are also looking at these two different alternatives of a Fickel alloys. So again, we're focusing at what the NRC has categorized as near-term a client technologies. And then in these micrographs, we see that we are dealing with different microstructures of the Fickel alloys for the APMT and C26M. And we are very interested in this particular aspect because it will provide us information on how the microstructure affects the properties and a performance of the materials in the testing procedures. So this is the quenching device that we have been able to design and build at Virginia Commonwealth University. So I want to emphasize a couple of features here. So we are looking at induction heating to be able to rapidly heat the materials at rates that can achieve approximately 100 Celsius per second. And we have adapted to the system an optical pyrometry device to monitor the temperature of the material through the testing procedure. And you see in the figure on your right, we have incorporated different inlets to our system in particular force so that we can provide steam and steam inlets so when the material is being heated up, we can incorporate steam as well as argon in case we need to purchase the system prior to testing. And finally, the quenching portion at the bottom so we'll be flowing water. So we've been doing this testing by flowing water from top to bottom so that we can rapidly cool the materials under a selected condition. And you see here in the figure at the bottom the holder for the cladding specimens. So this is just a video to show you how we're running the experiments. The induction heating allows to basically induce current in the cladding material and a ramp up the temperature of the cladding components. And then at a set time, which again we are establishing based on the protocols and recommendations by our by GE and we are looking at there how the water flows from top to bottom. Again, we can control the rate at which the water is flowing and we can monitor the temperature using a data acquisition system that you see on the right. Now, these are some preliminary results. So we have completed the stage of characterizing the temperature dispersion device and calibrating it. So since we know that the accessibility to these accidental ramping cladding materials is not that easy, so we have been using CIRCALI-4 and CIRCALI-702 as surrogates to calibrate our device and identify the parameters that we want to use for the testing protocol. So here in these images I'm showing you some preliminary results at different power levels that we incorporate in our induction furnace and you see there in the graphs how we can control the temperature at which the testing, at which the materials are heated and we can also control the heating rate in the experiments. So we are currently running experiments with the ATF cladding materials that we have in our facility. So right now we are just compiling our results and providing insights on the surface characteristics and mechanical problems. So just to continue with the preliminary results that we have with the CIRCALI-4 and CIRCALI-702, we have conducted tests on looking at a steam oxidation of the materials, rapid heating and rapid cooling or quenching. And you see here that we can evaluate the growth of the oxide layers in the materials. So in these particular cadence we are dealing with CIRCALI, we can see the oxide formation, the alpha phase and the prior beta phase. So again it's provided with a baseline as we move on on to the testing with ATF cladding materials. Now another topic that is a part of this project is looking at a techniques, non-destructive examination techniques to a for quality control of ATF cladding materials, in particular looking at coated cladding. So one of the aspects that influences the performance of these materials is defects in the surface. So we are using and we are implementing this technology, X-ray effects, ray fluorescence spectroscopy as a way to identify features and defects in the surface of these materials, looking at cracks and a lack of coating in particular regions in the material. So we have done a tremendous progress in this component as well and we are looking at this from both sides experimentally and computational. So we have one of the faculty is focusing on this component, looking at benchmarking through MCMP simulations. So we are characterizing the X-ray beam that we are currently using for this particular task as well as looking at the signal that is expected to come from the analysis of these coated cladding materials using this particular technique, X-ray fluorescence spectroscopy. So we are aiming to implement it to identify features and defects in coated cladding. All right, so with this I just want to wrap up my presentation with some concluding remarks. So the first one being that we are fully focused on investigating the near-term technologies, a coated coated, coated, coated, coated 4 produced by both PVD and cold spray as well as a thick roll alloy. We have advanced tremendously on the design and a implementation of our induction furnace for the rapid temperature excursions as well as the quenching procedures for the rapid cooling of these materials, looking at and investigating the ductility, a residual ductility of these materials after testing. Then we have conducted again preliminary tests on a cercaloi that allows to characterize the testing device and it provides us with protocols that we can implement later on in the APF cladding materials. And finally we have done a tremendous amount of work on MCMP simulations looking at a X-ray fluorescence spectroscopy technique for non-destructive characterization of coated cladding materials. So now our future work and this is the component that we are going to start early in the summer semester in the university with our students is looking at the dry storage conditions and testing the dry storage conditions and temperature profiles that following the regulations and guidance in the literature so that we can identify the changes in mechanical properties of these materials after testing with our quenching facility. So with all that I want to complete my talk. Thank you all for listening to my presentation and I'm happy to take any questions. Thank you very much Dr. Rojas. Yeah you can we can share a mic here. We've got a couple of questions on your presentation. The first one is sorry that's okay and then it's your turn. So in the the ferrous chromium aluminum alloy that you're looking at have any hydrides been seen in the grain structure that could reorient or create a potential through wall crack in the cladding and if not is the is that alloy then not taking up hydrides? That that that's a very good question there so currently we haven't identified any a hydride formation in the fecral alloys so again and this this is a with the a a critical heat flux studies that we have performed in the past so now we are transitioning to high temperature excursion profiles so short term a rapid heating and rapid cooling so this is something that we will definitely be investigating with the results that we are a collecting now and I think this next one is really interesting as well and so are you examining the vacuum drying conditions of the ATF cladding as part of the dry storage research and if so kind of what's the maximum temperature then that you're allowing the cladding to reach? That is a good a question as well so yes so we are following the the a regular a regulatory and the a guidance says of reaching a 400 Celsius in temperature as it's been done with the CERC alloy so those are our parameters a that we are currently investigating so we are looking at a particular temperature profile in the dry storage conditions and applying hoop stresses in the cladding material at the same time as while we're heating so that is the simulation that we are doing with the cladding materials so the mechanical testing portion we have already designed the device so it is a quantum mandrel mechanism to apply the hoop stresses and apply the temperature profile that is the so I like those detailed questions but let me let me zoom out a little bit and ask you another one and so is the day is the purpose then of the research to evaluate certain cladding concepts or is it more to develop an overarching kind of performance model at a at a and a more general scale I guess okay so yes so the basic a or the fundamental question that we are trying to answer is investigating how rapid the accident or learning field cladding materials can respond in an incident scenario so we are looking at rapid temperature a rapid temperature discursions right and a quenching so with that in mind we can evaluate the mechanical performance of the material in these a conditions and understand how a ductile the material they remain in ductility in the material after this kind of test so we are looking at a surface chemistry looking at what oxides are formed how thick they they are how much of the cladding react in this process and again how the material will transition later on to dry storage conditions and how a these a how it affects the performance in dry storage so that's the overall a quote in the project probably should have started with that question but we got there eventually but thank you very very much dr. Robas our next presenters are dr. Henry Spitz and jimmy stringer dr. Spitz is a professor of nuclear and radiological engineering at the university of Cincinnati's college of engineering and applied science he holds joint appointments in the department of mechanical and materials engineering and the department of biomedical engineering after obtaining his doctorate from new york university he worked as a senior research scientist at the batel pacific northwest national laboratory and thereafter at the mound research laboratory in miami's burg ohio he joined the university of Cincinnati in 1991 where he established the laboratory for radiological assessment and measurement where students learn methods and procedures measuring and analyzing samples containing radioactive materials dr. Spitz developed the university of Cincinnati in vivo radiation measurement lab a whole body counter with two large shielded rooms containing multiple arrays of scintillating and high resolution detectors for in vivo measurement of internally deposited radioactive materials he teaches undergraduate and graduate courses in health physics radiation detection environmental radioactivity and nuclear forensics dr. Spitz and his students design and fabricate tissue substitute materials and anthropometric phantoms that are used by institutions worldwide to calibrate systems that measure internally deposited radioactive materials his current research focus is to develop a practical robust method for evaluating direct in vivo measurement results of internally deposited isotopic mixtures of uranium plutonium americium and other actinides relevant to the composition of new and mixed oxide nuclear fuel waste streams related to small modular and advanced reactors jimmy stringer is currently a phd candidate at the university of Cincinnati mr stringer graduated from zaver university with a bs in physics in 2009 mr stringer continued on to receive a masters of science in medical physics from the university of Cincinnati school of medicine in 2011 after his bachelor's and master's degrees mr stringer was commissioned as an officer in the united states air force where he served four years as an active duty bio environmental engineer and medical physicist and five years in the air national guard during his tenure in the u.s. air force mr stringer created a career progression pipeline for medical for medical physicists in the air force deployed to afghanistan and was chief bio environmental engineer for the mansfield lawn airfield after his military service mr stringer was recruited to the anarbor veterans hospital where he eventually became the chief of medical physics currently mr stringer is a clinical diagnostic medical physicist for the university of Cincinnati health system mr stringer is a board sort of is board certified through the american board of radiology and therapeutic medical physics and diagnostic medical physics the topic of their presentation will be in vivo measurement of low energy photons following internal exposure to waste streams derived from mix oxide nuclear fuels i now turn it to dr spitz and mr springer thank you let's go back just one i'd like to thank nancy hebron israel and of course casper sun for giving us the opportunity to make this presentation about our research our study involves a forward-looking evaluation of a method to monitor workers who may receive occupational exposure to these new waste streams that will be generated by new designs for nuclear reactors and fuels these waste streams are predicted to contain a much greater much more significant quantity of actinides in those present now and that provides us with increased potential for risk our research team involves nuclear engineers health physicists and chemists and builds upon many years of developing methods to measure and evaluate internal radiation exposure now our experience our meaning the collective ours our experience with high burn up mixed oxide nuclear fuels reveals a very complex waste stream containing transuranic isotopes of americium plutonium neptunium curium that emits a poly energetic spectrum of low energy x-rays and photons raising from just teens up to about 120 kev but and i'm showing you the photon spectrum for a couple of those but this is what we expect to see and trying to measure that in vivo in a person is quite challenging since we expect to observe a much more complex poly energetic spectrum in these news waste streams it's really necessary to improve monitoring methods for those that might be exposed to accommodate this change now the first line method to measure occupational exposure to measure and evaluate occupational exposure involves as you see on the right hand illustration the picture placing detectors on the chest of a worker to detect activity in the lungs the generic name for this is whole body counting but more so it's now called direct bioassay versus indirect bioassay where we collect excreted from a worker the detectors are calibrated using phantoms these are surrogates for the human structure that you see on the left hand illustration and these surrogates these phantoms are made of of materials that simulate lung muscle fat and bone now the original materials that were made for the phantom shown in this slide were developed in the 1970s now that's back when i was even i was a graduate student and i got involved in actually evaluating this phantom for for the department of energy um the materials that were used for the surrogates are our base of a polyurethane and calcium carbonate and these the recipe for this was determined empirically trial and error by mixing different amounts of calcium carbonate to produce the kind of radiological characteristics of bone muscle lung and we try to match the mass density the electron density the effective atomic number the z effective and the attenuation coefficient we've done this empirically now the new formulations for tissue substitutes to work best with what we're expecting in these new waste streams we cannot be determined empirically they have to have an analytical method to help us come up with a recipe that will work and that's what jimmy is going to talk about today okay so um dr white established the mathematical basis for analytical development of tissue equivalence through the direct interaction method and essentially this is the cornerstone of modern-day tissue equivalent material design white's method allowed the tissue substitute designer to create a list of appropriate additives to combine with a base material to achieve tissue equivalence at a single energy our method combines white's method and an optimization routine to explore tissue equivalence for an entire energy spectrum so the experimental radiation physicists typically designs tissue equivalent materials to have tissue equivalence around a specific tissue type uh radiation um energy range and radiation type tissue equivalence presents a stoichiometric challenge especially when trying to mimic radiometric qualities of human tissue over a large range of energies characteristics such as atomic number electron density and physical density are critical to ensure that a tissue equivalent material effectively simulates the radiometric qualities of human tissues when a material meets the design requirements to radiometrically mimic human tissue it is termed tissue equivalent material the interaction probabilities of human tissue vary based on tissue type as can be seen from the graphs the contribution of photoelectric to the total cross section will change not just based off of energy but also based off of tissue type for the femoral head which contains a lot of calcium photoelectric is going to be pretty high at the lower energy ranges compared to fat and so your tissue equivalent your analytical method must take this into context now the the fundamental underpinning of the analytical tissue equivalent design method is matching the attenuation coefficient of the substitute material to the biological tissue under pre predefined conditions and in theory we would like to match the entire energy range for our attenuation coefficient but there is we can't we can't do this even with our analytical method because there's no combination of materials that you can mix together to match the entire energy range for a biological tissue just that's just a limiting piece of it because of the materials that we have available to us the pre the reason why we have these predefined conditions or the reason why they were designed is to make the formulation of tissue equivalent materials mathematically computationally feasible and empirically organized utilizing dr white's analytical method the tissue designer would determine the amount of constituent material to combine to match the radiometric characteristics of the desired biological tissue the determination of constituent material contribution presents an analytical mathematical problem that can be solved with analytical mathematical methods now when we take a look historically analytical methods utilize some of the analytical some of the preliminary analytical methods or methods used to design tissues utilize as dr spit said polyurethane and calcium carbonate as the added and didn't use a large group of additives to to be able to design our tissues the additive is used to increase the effective z the electron density and the overall attenuation coefficient of the base material why utilization of calcium carbonate is reasonable it has the consequence of causing significant increase in the amount of photoelectric effect at the lower energy ranges because of the high z of calcium and this this may be completely appropriate for tissues such as bone where calcium is a large constituent of the of the chemical makeup there but it's inappropriate once again for things like soft tissue adipose and muscle especially if we're concerned about matching throughout the entire spectrum this is to say if I match the total cross section at a higher energy for for for muscle I might be causing a over response at the lower energy due to photo photoelectric so so when you're designing this this analytical method or this optimization you have to keep that in mind that it's not just the total cross section that we're just we're considering we also considering the individual interactions that occur at the photoelectric Compton and so on and so forth level while white methodology is widely used its use is only appropriately for a very limited energy range tissue substitute design multi-energy tissue substitute design creates a higher level of mathematical complexity where no definite answer can be determined that will exactly match all the attenuation coefficients that all energies with multi-energy tissue substitute design the problem of determining determining appropriate tissue equivalent material component weightings is still analytical but a reasonable solution can only be obtained numerically the numerical method needs to give the best approximation for a solution that optimizes the match of the attenuation coefficients between the tissue substitute and the material and the biological uh tissue at multiple energies mathematical optimization allows the user to determine the maximum or minimum value of an objective or a cost function the user can also constrain the optimization for a for specific variables that may impact the outcome of your optimization this is known as constraining your optimization the fundamental conditions of our optimization problem is mathematically described above we want to minimize the difference of the attenuation coefficient for biological tissues and tissue equivalent materials for all energies this optimization has constraints that limit the variance between the tissue equivalent material and biological tissue tissue at each energy this is to say that instead of telling the optimization routine to perfectly match the attenuation coefficient at each energy bin we allow for a reasonable amount of variance the reasonable amount of variance allows for a solvable problem because as stated previously there is no combination of of materials that exist that will exactly match the attenuation coefficient at each energy bin and under any circumstances the other constraint dictates that the total constituent weighting fact that the total constituent weighting factor will need to add up to one this also means that the constituents that the algorithm calculates will be 100 of the total volume of the attenuation equivalent material in this research our team utilizes the limited memory brood and fletcher gold farb shadow algorithm this algorithm is an iterative quasi-nitonian optimization method that utilizes the direction of steepest descent to minimize an objective function this algorithm calculates the derivative of a cost function to determine a direction of descent and interrelief searches for a minimal value for minimization problems the cost function is typically the squared difference between a true value and the algorithm's guess per iteration steepest descent methods steepest descent methods require the selection of a starting point and the determination of a of a direction but they also require is that your cost function be differentiable and smooth the cost function has this the cost function that we chose has two weighting variables w p and w i w p determines the importance of minimizing density error versus minimizing the error of the attenuation coefficient increasing the weighting value for density increases the likelihood of matching the density of the tissue equivalent material while allowing a smaller penalty for error in attenuation coefficient uh error reduction of error for the attenuation coefficient and density are competing design parameters w p can be a value from zero to one and scales the square values and scales the square errors for density and attenuation w i is the volumetric weighting factor for each tissue substitute component w i considers the relative importance of the energy and the interaction type to be matched this is done by calculating the energy loss term with a normalized relative spectrum contribution by weighting the energy loss term the relative spectral fold time contribution the importance of the interactions and the energies that occur more frequently is increased they're in decreasing the penalty for not matching less frequent energies and interactions that will occur are less likely to occur within your spectrum the algorithm is based on the selection of a single base material and inevitably increases the amount of additive contributed until the tissue substitute materials radiation characteristic matches the biological tissue extensive knowledge of the chemical composition of the base materials and additives are needed to appropriately model the tissue equivalent material because of the proprietary nature of the available base materials uh polyurethane we have to obtain radiation characteristics of the base empirically which kind of you know that kind of extended our research some because we had to actually go in the lab and measure the the radiometric characteristics of our base and not not get them from model so what does our optimization require um human tissue coefficients from icru 46 or 44 that gives us what we need to match to measure coefficients of our base as we said before calculate attenuation coefficients from our ad is using xcom which is a nist database that allows you to determine the attenuation coefficients for multiple a multiple number of chemicals and elements and also what does it spit out for you it spits out the volumetric weighting for our additives in our base so it'll tell you this is how much of your base you need to add and this is how much of your your additive you need to add to get um to get the tissue equivalents that you desire so um um we had to manufacture these tissue equivalent materials once we got our answers from the uh uh from the um optimum optimizer and essentially um we have a high-period germanium detection system americium europium source um and we took that we essentially did attenuation measurements where we took measurements with our material in inside the beam versus divided by the measurements without the material in the beam and we attained our attenuation coefficients from there so preliminary kind of measurements um compared to icru 44 is that we get really really good agreement between what we what we calculate using our optimizer versus um what the what icru 44 and 46 says we should get and this is particularly for fat um and and right now it's underway that we're we're designing tissue for for muscle and for um uh for um for bone and we expect some of the same results so these are our preliminary results from from uh from our experimentation so in conclusion optimization method was applied uh to in the formulation of an adipose tissue substitute that exhibits desired radiological response between 13 and 200 kev um our ongoing research collaboration once again we're developing um we already have the optimum optimization done for the muscle bone we have not done it for long and our our next step is to um with that is to to actually make it and measure it and then we're going to design a fabric eight a revise thorax phantom for mv bowl measurement of mix oxide nuclear fuels thank you thank you uh both very very much um for that um mr stringer i think i'll i may start i may start with you um the question i've got is did you have any better blueprints um you know references to build your phantoms other than the information provided in both icru reports 44 and 46 and and if yes kind of what area and why is it better than that of the icru reports for your r&d so um i think the fundamental concern of our research was to see if we could um create a piece of software or algorithm that could where we could take two different or multiple different constituents to get a desire attenuation coefficient so the essentially the the resources or the references that we use are relevant when we bring this to to when we bring this for actual research but first the initial piece was just making sure that our optimizer could give us an answer could give us an answer so that's that's the first piece um second piece is we're not looking to make better formulations um we're not looking to improve icru 44 icru 46 we're just looking to match to be able to make tissues that can match the attenuation coefficients from those resources so it's not um it's we're not trying to improve icru 44 slash 46 we're you know that that's not our that's not what we're trying to do yeah yeah okay um so in that case it's really rather than using uh uh live tissues or a live something right basically to come up with that substitute that acts the same way uh yeah yeah yeah essentially we're saying hey we have polyurethane we have these additives yeah and what ratio can we add these to um get what the icru says we should get for prostate okay for bone it's it's not a it's not an improvement on those formulations or on those attenuation no please yeah so back in the 1970s when we were making recipes for tissue standards we were concerned only about plutonium that was the the reason that you saw that phantom that's why it was developed it was to be able to evaluate plutonium in the lungs and the recipes that were developed were tested you can't do this today but we had volunteers inhale not plutonium but they inhaled labeled particles of of niobium and palladium and we inter-compared the phantom response to the actual response of the individuals who were measured in vivo and we determined hey this matched well and we compared the response at several different measurement sites usually the national labs but this was an international study but all of that was for let's just say 20 kev our challenge now is to develop tissue substitutes that go from the teens up to 120 kev because we're not just interested in plutonium 239 the weapons material we're interested in a lot of other actinides that have a whole range of photon and x-ray energies that will help us determine whether a person has been exposed to the point where we have to take remedial action and we don't have that right now because the materials and the calibration device are for lower energy photon it's not for this continuous range of photon it's interesting you wrote a plutonium and that because as you both were talking this was part of what I was thinking and I'm I'm I'm struggling to remember the name of the individual who was exposed at hand heard in the plutonium finishing plant back in the day well I knew that individual very well okay and did we did we learn anything from that from that we we have a whole issue of the health physics journal okay that was published that has results of all of those measurements I don't think we really have a lot of time to go into that no I'd love to probably not but was but there were the things that we learned from that relevant or or unfortunately the the worker was exposed to americium 241 and he had a lot of shrapnel in his face so we weren't able to measure the plutonium I said we were measuring americium 241 he was involved in an accident at a glove box where the front exploded and there were ionization ion exchange columns loaded with america so he got a lot of america in his body we did learn that our radiation protection standards are adequate but this was an accident incident and a very complex situation but it wasn't thank you thank you for clearing that up for me this next question it was one I had the exact same thought on the phantoms in the pictures in your slides were appeared to be based on male anatomy and are there different tissue differences in female anatomy taken into account or how are they taken into account for example mammary glands in the chest in a chest scan etc yes so to give you some perspective on that our research not only has applications here but it also has applications in medical physics for designing phantoms for like CT scanners and for dosimetry for radiotherapy so what you see in that image is actually a electron density the house well you need calibration phantom that we're designing using the same sort of tissue design ideas that we discussed here today and yes there are differences and from just some of the preliminary research that we've done there's differences between bone density size all that stuff between men and women racially there's differences in bone density and size of anatomy so there's a whole spectrum that exists that really needs to be investigated to understand how radiation actually differs in the in deposition for men for women for somebody who's 60 versus somebody who's 18 versus a black male versus a white male there's there there is some substantial anatomical differences that we want to investigate with our research and that we want to investigate through finding those differences through or really really highlighting those differences in designing of tissue equivalent material through our algorithm so yes thank you very very much thank you both our final speakers are Dr. Benzi and Joy Chen Dr. Benzi currently serves as an assistant professor in the department of civil and environmental engineering at the University of Maryland she's an affiliated faculty member of both the University of Maryland Center for Risk and Reliability and the University of Maryland Center for Disaster Resilience Dr. Benzi's current research centers on the application of probabilistic risk assessment concepts and tools as well as statistical machine learning techniques to problem-solving involving engineered systems particularly nuclear power reactors exposed to natural hazards Dr. Benzi focuses primarily on topics related to the probabilistic assessment of natural hazards and risk-informed applications Dr. Benzi works with many natural hazard groups for example seismic coastal and fluvial flood hazards as part of our research activities and aims to transfer knowledge and lessons across those conventional disciplinary divides Dr. Benzi serves as a full member of the American Nuclear Society and the American Society of Mechanical Engineers Joint Committee on Nuclear Risk Management and chairs the working group responsible for the ANS-ASME standard for external flooding PRA at nuclear power plants prior to joining the University of Maryland faculty Dr. Benzi worked right here at the NRC where she was heavily involved in the agency's response to the Fukushima Daiichi reactor accidents Dr. Benzi earned her PhD in civil engineering with with designated emphasis in computational science and engineering from University of California Berkeley Joy Shen obtained a BS in mechanical engineering with a minor in nuclear engineering from the University of Maryland at College Park she continued her education there and currently is a PhD candidate in the reliability engineering program advised by Dr. Shelby Benzi and Dr. Muhammad Madaris her research interests include Bayesian network modeling external flooding PRAs and PRA tool research the topic of their presentation will be advanced will be advances in PRA technologies and a hybrid approach to PRA development I'll now turn it over to Dr. Benzi and Joy Shen all right so I'm I'm sure we have a lot of women on the stage today we're interested diversity podium should be shorter all right so I have a different topic where we had fuels we had human tissue now we're talking about external hazards and risk assessment so I'm going to talk today we're going to talk today about an ongoing project we have looking at a hybrid approach to external hazard risk assessment particularly we're focusing on external hazards in the interest of the time constraints we're going to sort of keep this high level but we'll have a stick around after and can talk to you more about it all right so if you're a PRA practitioner you're aware that PRAs have been the foundation for risk-informed decision-making for decades the nuclear industry really pioneered probabilistic risk assessment and has been instrumental in the development of PRA tools and methods because of this decades of investment the industry has a very robust and extensive experience space in PRA and now we have very robust models at each of the individual plants all right so that now I actually can hear me all right so you heard something along what I said earlier maybe yeah all right so you know you have this extensive knowledge you have these plant PRAs that encode a substantial decades worth of plant knowledge and experience however these these tools that were pioneered in the nuclear industry and are continued to be used are based on technologies that reflect some of the capabilities and characteristics of the time in which they were initially developed so things like inventories and fault trees which we're calling here these conventional PRA tools there may not be reflecting all the advances in capabilities that we have today that being said they they encode this extensive knowledge they've enhanced our knowledge of plant risks of plant systems they provided a great deal of insights but because of these the nature of these tools they they do have some key limitations so some of those being they had some inherent in independence assumptions there's the static treatment of time at least from the perspective of the logic structure there's some binary assumptions that are built into those tools and as PRA the use of PRA has expanded the scope has expanded the technical complexity and sophistication has expanded those limitations have been an issue so there have been various workarounds that have been developed over the years some of these workarounds are great some of them may you know reduce accuracy they may mask vulnerabilities and even when they do work well at the very least they do reduce overall model transparency and so as you've had this growth of and continued development of these PRAs in the nuclear industry as I mentioned you've had continued research and development in PRA methods in general so there are alternate techniques available that can be used so we're in this situation now where we have on one hand this really really robust experience base built in these conventional legacy PRA tools and then on the other hand we have some more modern methods that maybe overcome some of those limitations that are in the conventional tools they have some limitations themselves so we want to be able to do is link these two things so that we can get the best of both worlds and so that's actually what we're focusing on here in this particular research project is is looking at this notion of a hybrid framework and we're zeroing in on external hazards because external hazards really highlight some of these challenges related to the inherent characteristics of these conventional PRA tools and specifically we're zeroing in on external flooding as a as a target of focus and the reason for this is one external flooding extra extra highlights some of these particular challenges but also there's some co-benefits there hasn't been a lot of investment from across the industry in external flooding PRA over the years so if we're going to focus on a hazard let's focus on one where we can actually look at these hybrid tools but we can also advance the state of knowledge as we're going about doing that so what exactly are we doing so so this is the the sort of task breakdown of this overall project so we began with a survey and assessment of what risk methods and tools are out there in the literature that have been used in practice next we had a tasking to engage the broader PRA community to gather their insights about what are the current tools what are their capabilities what are the limitations originally this was going to be a great in-person engagement and then the pandemic happened and we didn't and so we actually used a questionnaire which we'll talk about which turned out to work well we then engaged further with the community via some conferences we identified the need for some supplemental vendor engagement and then building on all that that those information insights from that review and then engagement we're building a framework for this hybrid risk modeling approach and then demonstrating it via a case study and then finally looking at how the use of such a framework would impact risk-informed decision-making and what what are the potential implications of that framework so now I'm going to turn it over to Joy Shen Joy is is a PhD candidate but she's also the lead graduate researcher working on this project so Joy take it away I think this is the largest room you've ever presented in so yeah awesome thanks for reminding me as Dr. Benci just said we engage with the international PRA community through an anonymous questionnaire we were pleased to have received over 50 responses and from that we gained insights on advantages and limitations of the current fleet of PRA tools as well as allowing us to understand and identify the trending needs of the PRA community so from there it was interesting to find out that insights were a bit in the eye of the beholder for example for some responses advantages there were others's limitations so after this initial study we engaged with vendors of conventional PRA software this provided them an opportunity to further discuss clarify their respective tools and as a result of that we interestingly found out that some of the challenges and limitations provided by the respondents didn't quite reflect the actual capabilities of the existing tools so I would also like to mention this is still ongoing research and if you're interested in providing feedback and your insights you're more than welcome to by following the QR code at the bottom left so if you're already submitting questions you might as well give us your insights well you're at it so so we did a qualitative analysis on the responses that we had we broke down our findings to two overarching themes the first as you see on the left under technical modeling themes and the other on the right of PRA software implementation and management beginning with the insights on the right hand side we saw an interest in integrating pre and post processing of data as well as an interest in incorporating collaborative and version control features such as online repositories which makes sense since PRAs are highly interdisciplinary moving back to the insights on the left hand side under technical modeling themes there was a strong interest in dynamic PRAs as well as an interest in improving SSC dependency modeling incorporating Bayesian updating capabilities expanding the PRA scope to other applications particularly external events and as well as improving HRA capabilities so as you'll see in a moment we'll be focusing on four key insights under the technical modeling side of things as you see in bold we would like to acknowledge and recognize that there's a need and importance for dynamic PRAs however due to the scope of this project and I would like to graduate soon we will be incorporating the dynamic considerations through temporal dependence rather than developing a full scope dynamic PRA so here's how we'll do it we'll be beginning with the conventional external flood PRA framework that we all know and love it consists of a hazard analysis fragility evaluation and plant response which is based on event trees and fault trees however as Dr. Benson mentioned these models are not without their limitations so in response we'll be strategically integrating alternative modeling techniques into the conventional PRA framework to address the limitations of the conventional frameworks such as the binary assumption challenges to common cause failure modeling etc specifically we are proposing a Monte Carlo simulation augmented Bayesian network it's kind of a mouthful but and from there we'll be able to address some of the limitations that we just mentioned as well as attempting to incorporate or as well as incorporating the insights that we gain from the questionnaire responses so as an example this is a proposed Monte Carlo augmented Bayesian network in this case this is a Bayesian network that can probabilistically map external flood heights to internal flood heights while accounting a diverse set of random variables the logic of this Bayesian network here follows the idea that there's an external flood it affects a building on a nuclear power plant site so we can first start by describing the external flood itself by modeling relevant random variables in this case we're modeling flood duration and water level for the relevant random variables as well as accounting for site level and location specific hazards then moving on once you've described the external flood we must consider the condition and performance of the flood protection features so for example in this case these nodes describe the pre-existing degradation of the flood protection features in our example we have leveraged nrc sponsored research by Ma et al to define the associated probabilities next once we've modeled the pre-existing degradation or the condition of the flood protection features we can look to the performance of the of those features which is typically described by fragility and fragility correlations however it's fairly well known within the external flood PR a community that there isn't a lot of literature about flood fragility development so in our case we did an extensive literature review particularly in this case on penetration seals however this can be applied to other flood protection features and that consisted of an extensive review of manufacturing specifications of penetration seals as well as looking at strategies and modeling techniques from other hazards such as seismic which has have relatively more development compared to external flood fragility development and then finally we can move on to describing the internal flood demand when once we've been given the the performance of the flood protection feature so in in in order to understand the internal flood demand we look to physical relationships and also to minimize the discretization error and reduce computational expense of you know running this pretty large Bayesian network we use a Monte Carlo simulation to integrate out relevant random variables and in this case we have as I mentioned before probabilistically mapped it from the external flood height to the internal flood height but we can also continue expanding this Bayesian network to include the performance of internal components within the interior of said building so where's the hybrid part of this we need to connect the results of the Bayesian network back into the conventional PRA model because as Dr. Benz mentioned there's a lot of wealth and a wealth of knowledge in in this framework so we're considering two approaches to accomplish this the first as you see on the left is the hybrid causal logic model which has been developed by various researchers this this involves taking the Bayesian network results and inputting it into the fault tree which then will inform the event tree the other approach that we're considering is a more function focused framework this this involves taking the results of the Bayesian network and directly inputting them into the event tree so I'll take pass it back to Dr. Benz see to finish out the progress that we've done you did awesome joy so where we stand on this so we have most of the sort of background and outreach activities to date have been completed so we've completed that literature survey the engagement and the sub with the community and the supplemental engagement with vendors that being said don't forget that qr code that joy put off if you really if you want to add your thoughts to the data set we we can revise our results to reflect additional data and then what we have right now is we do have that initial framework developed and then we are actively working on that case study as joy showed and then the idea will be once we wrap up that case study go back maybe refine the overall framework and then our next steps are to move on to looking at that risk informed decision making and what does using something like this hybrid framework we we can overcome some of those inherent limitations of the existing tools what does it mean for risk informed decision making all right so with that as we're wrapping up I want to make sure I acknowledge my co-pi Dr. Mohammed Raderis he's sitting down there in the second row so he's he's obviously a key part of this project joy is the lead graduate student researcher but she has received some support from additional students in the in the in both civil and mechanical engineering as well as one anthropology student so Konstantinos and Sam have supported graduate researchers and Olivia has helped a bit particularly with the literature review activities and we did just have to scratch the surface with some highlights so we do have a few papers that have come out or that are forthcoming that we can share with you or reach out to us via email or if you happen to be in the area next week the nrc pfha workshop is going to be happening and joy will also be presenting there so that'll be a great opportunity for some further engagement if you would like to learn more and tell us your ideas so thank you thank you very very much uh Dr. Betsy and and Ms. Shen do vendors of existing pra software have improvements under development based on your survey responses etc sorry the question was do exist pra vendors have improvements development uh under development are they working to make them better so you've actually talked a lot so why don't you take that one so i i meant as i mentioned we engage with the conventional pra vendors and all of them had said like yes we are listening to our end users our clients if you will and there's a lot of the things that we brought up in regards to the trending needs within the pra community they were all very aware of it on for example the collaborative and version control that was a very common thing a theme that or insight that was brought up by a lot of them because i you know might have obviously been inspired by covid and having to work remotely with everyone and that really um highlighted the need that we're all very and what is the highly interdisciplinary um field not just pra but nuclear in general so yeah they are very aware i think if i could add too as i joint jerry mentioned this that we got feedback that said tools couldn't do certain things and then we were reporting what the server you know the respondents said and then the vendors were like uh we can and so there actually seems to be a communication this mismatch that is happening um it also was an interesting insight yeah um with surveying all these different tools i mean is the grant effort going to kind of recommend one tool or another and and if not which i would totally understand how do you kind of avoid that right i mean aren't people kind of pulling you aside at conferences and going no really which one is better yeah so um no we are not going to we are not going to play favorites um so i think one of the things that recognizes right is different pra softwares serve different needs they serve different constituencies so um i don't think we want to we want to you know to say that one is better than the other now for our purposes given access and cost uh we are we're doing a lot of work with that linking using sapphire and so that's what we are using but i but i would be the framework we're trying to develop here i would call it we're trying to be tool agnostic so we want to be able to to develop this framework that would be useful you know regardless of what particular um software application you're using now if we were to ever go further further to look at actual integration now we need to work with specific softwares to do sort of the behind the scenes software based linking well that kind of that's great that's actually a great segue to my next question which is which is you know could could you all develop your own pra software under the under the grant award so i don't so the the university of marilade has in the past developed pra software like modules i think if we're talking about commercial scale pra software the university is really not set up to do that scale of development right i think you know that's a that's a pretty big endeavor um and certainly not within the resources of the grant like this but i think the developing you know modules that can do something like a bayesian amonic simulation augmentation bayesian network and then partnering with a software so we can create that linking i think that's doable um but trying to come up with that we're not going to we're not going to uh put software out of business it's almost like a it's almost like a probabilistic or bayesian uh plug-in for for existing software if i if i understand yeah exactly yeah yeah okay no i think that's i think that's that's very very very interesting um for you know for everyone on the panel as we as we move into this and and thank you again dr bensey and miss shen for your presentation of the pra stuff obviously is something we're really interested in at the nrc which of course dr bensey you know uh quite well um but i guess uh i wanted to kind of ask a question kind of for everyone on the panel and that's can you share some experience on how your grant research may have inspired your students uh to become the next generation of engineers um in in a general nuclear engineering field or maybe some other specific field and do you think that some of these students may become i love that this is very leading i'm just i'm just now reading this right do you think that some of your students someday might want to come work for the nrc hint hint uh since we're looking for people as you may have heard uh and yes there are no and there is a right answer no there isn't uh but i but i do um i am a part of the part of the idea here is obviously to benefit the agency right with technical research on things um that are directly applicable to us and we've seen that across the board today um but also even when i go and and visit universities certainly i make the pitch for hey don't you want to spend a little time in public service um but but really it's also to encourage people more broadly and hey here's a world of possibilities around in the stem fields and around engineering more generally and here are the kinds of things that you can dive into in the hard questions you can really make progress on answering um and so that's also the point of of these research grants for us too so um you know uh maybe each of you can just take a couple of minutes and kind of talk about the impact of some of this in supporting students as they kind of pursue their interests and their passions in these fields yeah anybody anybody can start okay i'll start so okay so i think you know so i think that you know something like an nrc or any nuclear focused research grant is is unique you know nsf can fund research on flooding but only a grant like this can let us have expose the students to the truly unique context in which we're talking about risk and we're talking about nuclear power facilities so i think that's a particularly unique aspect and then for students to see what is you know what goes into a risk assessment for example for nuclear power facilities the other thing i think that's interesting is i talk with a lot of undergraduates and they think you know nuclear regulatory commission department of energy nuclear power plants they need nuclear engineers and i have to explain actually that's a little piece of a nuclear reactor right it's all civil and mechanical and so that's exactly what we what what this particular grant is is it's a partnership between civil and mechanical engineering to solve that so now we can start you know students can start to you know that may not have been thinking about nuclear the nuclear industry in general now they can start to think about this as a career pathway even though their degree doesn't have nuclear in the name and joy would you be interested in joining the nrc ever i love to yes actually i have i have to say she's a unique student she showed up to talk to dr madaris and me and said she wanted to do external floating pr like wow that is how you approached us right all right that's i mean that hey that is fantastic and useful in all kinds of ways i love it i'll give my perspective so just a going on the same a line as dr benz says so we a in virginia commonwealth university we have a hybrid department mechanical and nuclear engineering so we are somehow well positioned in the map so the students always have the nrc in their eyes so they they see this a entity as a potential a employer for them so and again this this project has given us the opportunity to target undergraduate students and graduate students at the same time and they are seeing all the benefits in all the different parts in the nuclear industry not only in the experimental part and computational part in the research component but also in the regulatory aspects as well so it's been a a really good opportunity for for our students to recruit them retain them and show them different a paths and of course a in contact with a contact with the nuclear industry as well thank you i've been at the university of sincini for a long time and the college of engineering and applied science is a five-year undergraduate engineering program it has a one-year mandatory co-op and during the co-op time the students are working in industry and so the employer who pays them this helps them with their tuition the employer who pays them gets to see if they're going to be good employees in the future and i must say a number of the of the co-op employers hire their students it's a very successful way to try out students and see if they do fit into your into your business and the nrc is just another business to them we have been successful in placing our graduate student i'm sorry our undergraduate students with the department of energy national labs industry i have a couple of students down at the new plant starting up they want in fact one student insisted on going down to vogal because he wanted to be in a startup team and so i think the nrc is just another one of the employers that that offers opportunities for our students in at uc our nuclear classes are really treated as technical electives we have students from all of the engineering disciplines and from medical physics and so forth and they learn about the nrc and what it has to offer and i i know of two students that have gone to the nrc for part of their professional careers and i would like to see the nrc and i know you have programs for for students to work at the nrc this needs to be more publicized i i would like i'd like to get brochures to hand out to students because there are students for which the nrc would be a wonderful opportunity for them it's exciting there's research our research program is relatively small we're very focused in a certain area and in the past we've had students two students in particular to that came to the nrc for a while and enjoyed it very much but there's a lot of competition you know that absolutely and it's send out brochures tell us about what's available and i think you'll get more students that way and more employees that way i i i think the point about the diversity of disciplines that we try to bring into the agency is really important but dr spitz you actually you raised a great question we were kind of having this conversation about you know how do you um what are the pathways maybe to get into public service whether at the department of energy or the nrc or other places but one of the questions we got through the app was was the flip side of that which is kind of what are the barriers uh to money um to newly really scientists become employing you know becoming you know applying to work at the nrc or other places it it's you know the the students when they graduate whether they're graduate students or undergraduates they have already multiple job opportunities and they're not foolish they're going to go where they've co-opped a and that's why i'd love to see a co-op pro offer co-ops it's it's a challenge because the co-ops are not doing xeroxing they're actually doing projects and they get a taste of what's coming this is the best way to get your employees see if they fit yeah to see if they fit you you make a big investment in hiring somebody um and that investment has to pay off so the co-op experience is wonderful the students just our students don't say in Cincinnati they go all over the country and they go international as well but the the bottom line for somebody just graduating college who's got debt tuition debt they want to go where they can help pay off their debt yeah so my experience as a former military uh or as a veteran um is with the gi bill and so um i think if the nrc could implement something of that extent where you pay for education or you you go back and do some reimbursement for a prior education you could probably get people to sign on for three or three or four well probably two or three years post uh undergraduate education i don't know if that exists but i i think that for a lot of people with the cost of the expense of college knowing that hey i can get a good co-op opportunity and i can get some of my debt paid off and i can get the public service in uh two to three years uh post undergrad that would probably attract a lot of people so i think that sort of program if you can do that would be work well thank you dr benzi yeah i think we had we're in a unique situation because we're you know right down the street and i we i know that um um d has hosted a number of the fellows for the nrc which is similar i think to what you said where existing employees can can pursue uh education i think mohammed i think you have a count somewhere of how many students have come to nrc and it's a pretty good number right um so you know i think one of the cool things about being here in the dc area is our students can come here i know i think there's how six students may be coming next week to the pfh workshop and so we and our students have a little bit of a unique opportunity here locally to attend these types of of conferences of do we have you know similar conferences so it's a it's a pretty you know we we're pretty plugged in i think to this particular career pathway but am i right mohammed you have it's a pretty good number right okay thank you yeah yeah no i think there's a lot there to for us to kind of chew on and think about and and and work on and how to sustain that pipeline right because the um um because the research ultimately that you all are doing right it's it's to move forward that body of knowledge that we're going to need to make to make robust and durable and um regulatory decisions right that protect people in the environment that's that's our that's um our mission um uh you know but also there's this you know creating the ecosystem of of of research professorships and student interest in these topics as well that then kind of benefit the entire um you know not only the nrc sure but um the kind of the the the community uh writ large so that to say nothing of then all of the uh you know the kind of incubators for innovation around this right the the plug-in the the the new model for for phantoms right um uh the the important work on um the performance of cladding um under these kind of extreme conditions right all of that then leads to further developments that also then improve safety performance human health the environment and all these good things so i want to thank you all very very much for being here today thank you it's been a great pleasure to uh to chair the panel thank you all for your research and uh let's give them a round of applause