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DOE OSTI2020

Enhancing nuclear data validation analysis by using machine learning

In this work, we demonstrate how machine learning (ML) techniques can be used as an auxiliary tool for nuclear data validation analysis. The output of the ML analysis can inform evaluators and validators on the quality, or lack thereof, of specific nuclear data and benchmark experiments with respect to simulating these experimental benchmark values. To this end, measured and simulated effective neutron multiplication factors, k eff , of 875 selected ICSBEP critical assemblies and the latter's sensitivities with respect to nuclear data as well as benchmarks' features (e.g., material nuclide, core geometry) are used as input for a random forest (RF) regression model. The RF is used to encode the complex inter-dependencies between thousands of nuclear data features (i.e., sensitivity profiles and aspects describing the measurements) and 875 simulated and experimental k eff values in order to understand what nuclear data features are most informative for predicting bias. The complexity of relationships and high-dimensional space is difficult-to-impossible to search fully using simply expert judgment. As a first proof-of-concept—step, it is demonstrated that this technique is able to correctly trace large discrepancies between simulated and experimental k eff back to fabricated shortcomings in nuclear data that were perturbed to simulated k eff values. In a second, real-case scenario, step, the RF algorithm is used to validate the ENDF/B-VIII.0 library in comparison to ENDF/B-VII.1 nuclear data. One case is showcased where the chosen ML algorithms highlighted nuclear data (the 19 F(n,inl) cross section from 0.4–0.9 MeV) that are shown to be problematic by comparing them to associated differential experimental data and nuclear data from other libraries. In addition to that, it is shown that the RF results point towards poor benchmark experiments and associated underestimated uncertainties (e.g., the PU-SOL-THERM-028 series). However, using the RF algorithm for validating nuclear data with respect to k eff is currently limited to pinpointing groups of questionable nuclear data due to the inherent correlations between features introduced by the nuclear data themselves and how k eff is simulated. Due to this, we recommend that the ML methods presented be used to augment—rather than replace—the expert knowledge of evaluators and validators.

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗

DOE OSTI2015

Application of Framework for Integrating Safety, Security and Safeguards (3Ss) into the Design Of Used Nuclear Fuel Storage Facility

Department of Energy’s Office of Nuclear Energy, Fuel Cycle Research and Development develops options to the current commercial fuel cycle management strategy to enable the safe, secure, economic, and sustainable expansion of nuclear energy while minimizing proliferation risks by conducting research and development focused on used nuclear fuel recycling and waste management to meet U.S. needs. Used nuclear fuel is currently stored onsite in either wet pools or in dry storage systems, with disposal envisioned in interim storage facility and, ultimately, in a deep-mined geologic repository. The safe management and disposition of used nuclear fuel and/or nuclear waste is a fundamental aspect of any nuclear fuel cycle. Integrating safety, security, and safeguards (3Ss) fully in the early stages of the design process for a new nuclear facility has the potential to effectively minimize safety, proliferation, and security risks. The 3Ss integration framework could become the new national and international norm and the standard process for designing future nuclear facilities. The purpose of this report is to develop a framework for integrating the safety, security and safeguards concept into the design of Used Nuclear Fuel Storage Facility (UNFSF). The primary focus is on integration of safeguards and security into the UNFSF based on the existing Nuclear Regulatory Commission (NRC) approach to addressing the safety/security interface (10 CFR 73.58 and Regulatory Guide 5.73) for nuclear power plants. The methodology used for adaptation of the NRC safety/security interface will be used as the basis for development of the safeguards /security interface and later will be used as the basis for development of safety and safeguards interface. Then this will complete the integration cycle of safety, security, and safeguards. The overall methodology for integration of 3Ss will be proposed, but only the integration of safeguards and security will be applied to the design of the UNFSF. The framework for integration of safeguards and security into the UNFSF will include 1) identification of applicable regulatory requirements, 2) selection of a common system that share dual safeguard and security functions, 3) development of functional design criteria and design requirements for the selected system, 4) identification and integration of the dual safeguards and security design requirements, and 5) assessment of the integration and potential benefit.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

Technologies to Reactors: Enabling Accelerated Deployment of Nuclear Energy Systems Workshop Report

Nuclear energy provides almost 20% of the electric power in the United States, producing power with high availability while accounting for 63% of our carbon-free energy production. While we have the capacity to expand this clean power source within the United States, we have not built any advanced reactor plant designs in our rapidly evolving electricity generation market, where cost is a major driver. With construction cost and plant safety being major elements of cost for new nuclear, advanced reactor technologies could provide lower cost, safer, carbon-free, grid-resilient energy sources for the US electricity grid. When the current fleet of nuclear reactors was originally designed, many of today’s science and technology (S&T) advances were not available. Today these advances show great promise for transforming our national approach to nuclear reactor design. Other industries are capitalizing on rapid innovations in materials, manufacturing, sensors and control systems, and high-fidelity modeling and simulation (M&S), along with data analytics to provide lower costs in manufacturing and extended ranges of operations. In the nuclear industry, these innovations can translate into similar benefits as well as rapid design and qualification of advanced nuclear fuels. Effectively implementing these types of innovations could position American expert leadership to compete more fully in the international nuclear energy market. In July of 2018, the US Department of Energy (DOE) Office of Nuclear Energy sponsored a workshop to address these possibilities: “Technologies to Reactors: Enabling Accelerated Deployment of Nuclear Energy Systems.” Workshop participants explored how modern and emerging S&T can be used to transform the approach to nuclear reactor design, licensing, and operation to accelerate deployment of advanced nuclear energy systems. More than 80 experts from federal agencies, academia, and industry participated in the workshop to develop consensus on priority technology directions (PTDs) and recommend technology and deployment initiatives to explore and demonstrate key benefits for the nuclear community.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2018

Categorizing An Explosive Device by its Nuclear Signature (Rev. 1)

This report documents a study to eliminate ambiguity in identifying a very low-yield nuclear detonation in the early stages of the response to such an event. The ambiguity arises from the very similar explosive and radiation effects produced by three categories of explosive devices: An explosively driven radiological dispersal device (RDD) or an accidental explosion in which radiologic material is scattered by chemical explosives. A failed nuclear device in which nuclear material, such as uranium or plutonium, has been scattered by conventional explosives. A nuclear device that, in addition to scattering nuclear material, produced a very low-yield from nuclear fission. The study found that the properties of fission products provide a ready solution to the problem. The radiation dose rate from fission products that were produced in a nearly instantaneous “fission event” decreases extremely rapidly over the first eight hours after that event, whereas nuclear materials and common radiological materials produce an essentially constant dose rate. This contrast provides an unequivocal fission product signature. The measurements required to utilize this signature can be made by first responders with radiation detectors already in the field, on time scales of an hour, although later confirmation using more capable detectors, including spectroscopic capability, is advised. The process of categorizing an explosives-related incident, both pre- and post-detonation, can be represented as a Decision Tree. The Decision Tree illustrates the use of already-fielded radiation detectors to categorize incidents as likely to involve only conventional explosives, an explosively driven RDD, or a nuclear device. The identification of an explosion as a fission event is extremely important to evacuation planners. It has been shown that delayed evacuation after sheltering in place for up to 24 hours after a fission event has the potential to reduce radiation exposure to the affected public and responders by a factor of ten. Traditional evidence collection after a nuclear detonation is likely to be similarly delayed, as the value and urgency of collection efforts must be weighed against radiation and other hazardous exposure of the collectors. The evidence that survives the immediate effects of a nuclear detonation will, in many cases, still be available for collection once radiation levels have diminished to acceptable levels. Certain classes of evidence, notably information stored on digital media, may significantly degrade from exposure to post-detonation radiation fields. Technical nuclear forensics collections will be performed in all events with nuclear yield. Modification of the high-yield collection strategy may be necessary for a very low-yield device.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2021

The Role of Nuclear-Conventional Intermingling on State Decision-making and the Risk of Inadvertent Escalation

The questions answered by this report are: What are the implications of nuclear and conventional intermingling on crisis stability and the potential risk of miscalculation?, and Specifically, how might entanglement influence US and competitor decision making during crisis and conflict? In practice, there are three main forms of nuclear-conventional intermingling. First, intermingling between nuclear and non-nuclear weapon systems can occur via the fielding of dual capable delivery systems like missiles or aircraft. Second, intermingling can happen due to the co-location of nuclear and non-nuclear forces and their support structures—for example, the co-location of strategic bombers and general-purpose aircraft, or the co-location of strategic submarines and general-purpose vessels. Third, intermingling can occur via convolving nuclear and conventional military command and control systems, to include ballistic missile early warning and potentially space surveillance systems as well. All three forms of nuclear-conventional intermingling have significantly increased since the end of the Cold War, driven by both technological and doctrinal changes. However, there are important differences in the rationale behind, and also the risks associated with these three different forms of intermingling. The mere existence of dual capable systems is not new— deploying such systems can increase the effectiveness of forces, and it can also provide more flexibility. The major powers have both employed and threatened with dual capable systems for decades, and they have done so without nuclear escalation. Similarly, the major powers co-located nuclear and conventional systems in the Cold War, and they did so for variety of reasons that had nothing to do with complicating the adversary’s risk calculus. The Soviet Union, for example, decided to co-locate its nuclear and conventional forces for economic and administrative reasons. Although today it might be recognized as a useful deterrent tool, it was not their primary intention. Major powers want to convince rivals that the co-location of forces creates a high bar for targeting and raises the risk of nuclear escalation, but they also want to have the flexibility of this not being true in an actual crisis or conflict.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2023

Analysis of Nuclear Fuel Cycle Data

Electricity generated using nuclear power accounted for 18.9% of all electricity consumed in the United States in 2021, putting it in third place behind natural gas (38%) and coal (22%) power plants. Nuclear power plants boast a significantly higher uptime or capacity factor—90% and above—compared to 49.1% for coal fired power plants and 56.6% for natural gas power plants. Renewable energy sources, such as solar photovoltaic (PV) and wind electricity, have lower capacity factors: 24.9% and 36.3%, respectively. In addition, nuclear power is cleaner than both coal and natural gas fired power plants. With the passing of the 2022 Inflation Reduction Act, significant tax credits will be claimed by producers of hydrogen with well-to-gate greenhouse gas (GHG) emissions below 0.45 kg CO 2e /kg H 2 . This has sparked interest in using clean sources of electricity, including nuclear power, to generate H 2 via water electrolysis. As uranium is a primary fuel for modern nuclear power plants, the upstream emissions from nuclear fuel production greatly impact the GHG emissions related to all nuclear power end use. Therefore, it is important to accurately determine the upstream emissions associated with the nuclear fuel cycle of nuclear power production in the United States. In this analysis, the nuclear fuel cycle was separated into distinct steps to allow better understanding of the chemical and energy inputs at each step of the fuel cycle. This also provides details of the GHG emissions at each step in the nuclear fuel cycle. The transportation distance for each step of the fuel cycle was updated to account for the locations of uranium processing facilities along the supply chain of the current U.S. nuclear power plants. Finally, all the updated values were incorporated into Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions, and Energy Use in Technologies (GREET) model.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2017

Used Nuclear Fuel Management in Asia

Used fuel discharged from nuclear reactors are presently stored in wet pools or in dry cask at-reactor and/or away-from- reactor sites. Only a few countries reprocess their civilian used fuel, notably France, Russia, and UK. No country has yet operated a geologic repository to dispose of civilian used fuel or high-level radioactive wastes (HLW). As a result, the management and disposal of used fuel and HLW are viewed as the Achilles' heel of nuclear power. Figure 1 shows the used fuel inventory in the United States (US) and East Asian nuclear power programs. The inventory is estimated based on that in 2010 and the projected growth of nuclear power in these programs to 2020 and 2030. Figure 1 indicates that in 2010, the US had about 63,900 tons of used fuel from light-water reactors (LWR), more than the statutory limit of what was supposed to go into the now-abandoned Yucca Mountain Repository, and accounting for more than 33% of global used LWR fuel total. Currently, about 2,000 tons of used fuel are generated in the existing US LWRs annually. Russia had 25,100 tons of used fuel in 2010. Based on a modest growth of nuclear power, its used fuel inventory is expected to increase to about 31,800 and 38,000 tons by 2020 and 2030, respectively. The nuclear energy programs in East Asia (China, Japan, ROK, and Taiwan) account for 19% of global used LWR fuel inventory in 2010. China's used fuel inventory in 2010 was relatively small at 1,900 tons, but is expected to grow rapidly to {approx}12,400 and {approx}31,000 tons in 2020 and 2030, respectively, based on its expanding nuclear power program (from the current installed capacity of 21.8 GW to {approx}60 and {approx}200 GW in 2020 and 2030, respectively). Besides PWRs, China also operates 2 Candu reactors which each produces roughly 8 times more used fuel in tons than a PWR of the same power. The used Candu fuel inventory would increase from 950 tons in 2010 to 2,850 and 4,750 tons in 2020 and 2030, respectively. Used fuel in Japan, ROK, and Taiwan are US-obligated. Japan's future trends of used fuel inventory are uncertain due to the unknown numbers and timing of the currently-shutdown nuclear power plants that would be allowed for restart, and the uncertain future of Japan's reprocessing at Rokkasho. Under two scenario cases (a no-nuke/no-reprocessing and a 80%-nuke with reprocessing), the Japanese used fuel inventory could be capped from 2020 to 2030 to {approx}21,500 tons for the first case, and to {approx}22,500 tons for the second. The ROK's used PWR fuel inventory would increase from 4,900 tons in 2010 to about 8,800 and 14,000 tons in 2020 and 2030, respectively. Its used Candu fuel inventory would also increase from 5,900 tons in 2010 to about 9,700 and 13,500 tons in 2020 and 2030, respectively. The Taiwan used fuel inventory should be kept at current level as nuclear power is being phase out. Its growth should be modest from 3,000 tons in 2010 to about 4,300 and 5,000 tons in 2020 and 2030, respectively even if the 4. nuclear power station would start and the operation of existing LWRs is extended. Used fuel inventory in other East Asian countries (DPRK, Vietnam, etc.) should be small, if any before 2030.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI1996

Nuclear Safety [Vol. 37, No. 2, April-June 1996]

Nuclear Safety is a journal that covers significant issues in the field of nuclear safety. Its primary scope is safety in the design, construction, operation, and decommissioning of nuclear power reactors worldwide and the research and analysis activities that promote this goal, but it also encompasses the safety aspects of the entire nuclear fuel cycle, including fuel fabrication, spent-fuel processing and handling, and nuclear waste disposal, the handling of fissionable materials and radioisotopes, and the environmental effects of all these activities. Table of Contents for this issue follows. GENERAL SAFETY CONSIDERATIONS: 97 The Nuclear Community and the Public: Cognitive and Cultural Influences on Thinking About Nuclear Risk, M. A. Meyer; 109 Twenty-Third Water Reactor Safety Information Meeting, D. A. Copinger; ACCIDENT ANALYSIS: 126 Analysis of a PWR LBLOCA Without SCRAM, Trevor N. Tyler, Rafael Macian-Juan and John H. Mahaffy; DESIGN FEATURES: 139 Vulnerability of Multiple-Barrier Systems, N. C. Lind; ENVIRONMENTAL EFFECTS: 149 A Study of Wet Catalytic Oxidation of Radioactive Spent Ion Exchange Resin by Hydrogen Peroxide, Xingchao Jian, Tianbao Wu, and Guichun Yun; 157 A Comparison Study and Resolution of Differences Between Emergency Response and Safety Analysis Codes Used at the Savannah River Site, A. A. Simpkins; OPERATING EXPERIENCES: 164 Reactor Shutdown Experience, Compiled by J. W. Cletcher; RECENT DEVELOPMENTS: 167 Reports, Standards, and Safety Guides, D. S. Queener; 172 Proposed Rule Changes as of Dec. 31,1995; ANNOUNCEMENTS: 178 American Nuclear Society 1997 Annual Meeting; 178 American Nuclear Society Nuclear Criticality and Safety Division Topical Meeting; 176 The Authors.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2025

Overcoming Challenges to Nuclear-Maritime Applications

This report is the fifth deliverable in a series of reports set forth by the Department of Energy (DOE), led by the American Bureau of Shipping (ABS), for the research award titled “Accelerating Commercial Maritime Demonstration Projects for Advanced Nuclear Reactor Technologies.” The report highlights guidance to bridge the gaps between innovative nuclear technologies and their practical implementation in maritime environments. The previous reports discussed specific technical, economic and regulatory challenges that may be expected when developing and establishing advanced nuclear technologies for commercial maritime applications. This report supports the mission of the U.S. National Reactor Innovation Center (NRIC) to demonstrate projects with industry and acts as a resource for the various stakeholders associated with the development of novel applications for advanced reactors. The previous reports discuss the interest in nuclear technology applications for decarbonized energy and identify the potential demands in nuclear energy supply and price. The work in these reports supports the recently issued nuclear Executive Orders (EOs). Specifically, EO 14299, “Deploying Advanced Nuclear Reactor Technologies for National Security”, and EO 14300, “Ordering the Reform of the Nuclear Regulatory Commission,” by ensuring the rapid development, deployment, and use of advanced nuclear technologies; and increasing the deployment of new nuclear reactor technologies, such as Generation III+ and IV reactors, modular reactors, and microreactors to support America leading the commercialization of affordable and abundant nuclear energy.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2015

Policy and Technical Issues Facing a Fissile Material (Cutoff) Treaty. Chapter 14

We report the largest obstacle to creating nuclear weapons, starting with the ones that destroyed Hiroshima and Nagasaki, has been to make sufficient quantities of fissile materials – highly enriched uranium (HEU) and plutonium – to sustain an explosive fission chain reaction.1 Recognition of this fact has, for more than fifty years, underpinned both the support for and the opposition to adoption of an international treaty banning at a minimum the production of more fissile materials for nuclear weapons, commonly referred to as a fissile material cutoff treaty (FMCT).

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2023

Women as a Force Multiplier for Bringing Nuclear Forensic Capabilities to the International Stage

In 2009, the US Department of Energy National Nuclear Security Administration’s (NNSA’s) Defense Nuclear Nonproliferation Program initiated a new nuclear forensics outreach effort under its Confidence Building Measures Program. Little did they know that the timing could not have been better. This article focuses on the early years (2009–2015) of the NNSA’s international nuclear forensics outreach, specifically the efforts and experiences of the women who helped establish this program, building it from a fledgling, bilateral effort into an enduring technical capacity provider engaging with dozens of countries and multilateral organizations. At the onset of the program, nuclear forensics was an emerging priority within the US Government and receiving increased focus from international organizations through high-level diplomatic efforts such as the Nuclear Security Summit and Global Initiative to Combat Nuclear Terrorism. Additionally, working-level initiatives were gaining traction through the International Atomic Energy Agency and the Nuclear Forensics International Technical Working Group. Over the next 6 years, a small team comprising a uniquely large number of women NNSA federal, contract, and national laboratory staff served as key leaders engaging with the international community to strengthen global technical nuclear forensics capacity and best practices. The program continues today under the Nuclear Smuggling Detection and Deterrence Program as Investigation Support. The experiences shared here detail a unique time period when the new technical discipline of nuclear forensics was beginning to mature and gain international traction. The authors have made every effort to remember history correctly and be as inclusive as possible. A wealth of training, guidance, and exercise documentation was developed in the 2009–2015 time frame, much of which still serves as the foundation for today’s even more extensive program and community of dedicated technical and diplomatic practitioners.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗

DOE OSTI2016

The Ambivalent Role of Participants in Nuclear Waste Decisions - 16360

Today's global nuclear sector has entered a critical juncture. Waste management solutions have the potential to influence the prospects of whether new plants will be built and when aging plants will be decommissioned. Even in countries without nuclear power plants, the siting of nuclear waste can present communication challenges and opportunities for public involvement. As new nuclear programs withstand scrutiny, local communities share their want for solutions to nuclear waste before new plant construction commences. Developing nations have begun to explore the potential of adding nuclear power production to their energy mix. They carefully watch established nuclear players to accelerate their plans with lessons learned elsewhere. Some newcomers to nuclear energy will make decisions on new construction based on other operators' abilities to reconcile public concerns regarding radioactive waste. Distinct forms of government, cultural norms and means of public discourse present innovative approaches and changing expectations worldwide. This paper explores how practitioners are evaluating ways to activate stakeholders on nuclear waste siting in nations embarking on new nuclear programs. It investigates the incentives that people have to participate and legitimize the formation of laws, regulations and standards for nuclear materials management. Finally, it highlights examples of public participation techniques from established operating environments and posits that overly prescriptive requirements for stakeholder engagement can reduce the authenticity of public involvement and weaken confidence among participants in the decision making process. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

Characterizing the Benefits of Seismic Isolation of Nuclear Structures in Terms of Reduced Risk and Cost

Seismic isolation is a mature technology that has been implemented in many civil structures, including buildings, bridges, liquid natural gas tanks, and off shore oil platforms, both in the United States and other countries, to mitigate the damaging effects of earthquakes. Seismic isolation has also been used in nuclear structures in France and South Africa, but not yet in the United States: neither in the Department of Energy facilities nor in commercial nuclear power plants (NPPs). This is primarily due to a lack of guidelines, codes and standards for the analysis, design and construction specific to seismically isolated nuclear structures. However, seismic isolation of nuclear structures has seen increased research interest in the recent years and the recently published national consensus standard, America Society of Civil Engineers (ASCE) Standard 4-16 'Seismic analysis of safety related nuclear structures', now incorporates language and commentary (Chapter 12) for seismically isolating surface or near-surface-mounted nuclear facilities, including NPPs. Seismic isolation substantially reduces horizontal seismic loads (demands) on structures, systems, and components. Reduction in demand results in four potential benefits: (1) economic: reduction in capital cost, (2) increased safety: reduction in the mean annual frequency of unacceptable performance, (3) insurance: protection against increases in the known seismic hazard after construction by minimizing the effort to re-qualify and re-certify structures, systems and components, and (4) recertification: the opportunity to certify an existing NPP design for a region of higher seismic hazard. Item (2) above, an increase in safety (reduction of seismic risk), was explored in Huang et al., wherein it was demonstrated that the implementation of seismic isolation reduced seismic risk in nuclear power plant structures. Studies that assess item (1) have not been performed although the use of isolation may lead to large reductions in the capital cost of safety-related nuclear facilities. Funding provided by Nuclear Safety Research and Development in the Department of Energy (DOE) allowed the authors to develop a framework for assessing the economic benefits and reductions in seismic risk afforded by the use of seismic (base) isolation. The framework includes probabilistic risk assessment and estimation of overnight capital costs (OCC's) of a sample generic DOE nuclear facility (GDNF). The project is documented in detail in Bolisetti et al. and Yu et al., and key results are presented here. The GDNF considered in this study is based on a facility constructed at the Idaho National Laboratory. The GDNF is a two-story reinforced concrete building with an embedded basemat and is founded on soft rock at the boundary of Site Class B and Site Class C (B/C boundary) as characterized by ASCE/SEI Standard 7. The GDNF is assumed to handle radiological materials, and its structure, systems and components (SSC's) are designed to effectively confine these materials in the event of an internal failure. The GDNF is populated with components that are generic to safety-related nuclear structures. A single system, which is intended to confine a loss of materials-at-risk (MAR) to the interior of the structure, is chosen for this study. Accordingly, a hypothetical event tree and fault tree are assumed for risk assessment. The isolation system for the GDNF is designed per Chapter 12 of ASCE/SEI 4-16 but is not optimized. The isolation system consists of 38 lead rubber bearings installed in one horizontal plane below the basemat. Details of the GDNF, including the SSC's, event tree and fault tree, and isolation system, are presented in the project report and Yu et al.. This study includes seismic risk assessment and cost estimation for four cases: (1) the GDNF is located at a site of low to moderate seismic hazard and is constructed on a conventional (non-isolated) foundation; (2) the GDNF is located at the same site as case 1, but is seismically isolated; (3) the GDNF is located at a site of high seismic hazard and is constructed on a conventional foundation; and (4) the GDNF is located at the same site of high seismic hazard as case 3, but is seismically isolated. In this study, the DOE site at Idaho National Laboratory (INL) is chosen as the low to moderate seismic hazard site for cases 1 and 2, and the Los Alamos National Laboratory (LANL) is chosen as the high seismic hazard site for cases 3 and 4.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI1996

Nuclear Safety [Vol. 37, No. 1, January-March 1996]

Nuclear Safety is a journal that covers significant issues in the field of nuclear safety. Its primary scope is safety in the design, construction, operation, and decommissioning of nuclear power reactors worldwide and the research and analysis activities that promote this goal, but it also encompasses the safety aspects of the entire nuclear fuel cycle, including fuel fabrication, spent-fuel processing and handling, and nuclear waste disposal, the handling of fissionable materials and radioisotopes, and the environmental effects of all these activities. Table of Contents for this issue follows. GENERAL SAFETY CONSIDERATIONS: 1 A Decision Support System for Maintenance Management of a Boiling-Water Reactor Power Plant, J. H. Shen, A. Ray, and S. Levine; ACCIDENT ANALYSIS: 12 On Prediction of the Ignition Potential of Uranium Metal and Hydride, M. Epstein, W. Luangdilok, M. G. Plys, and H. K. Fauske; 26 An Overview of the Primary Parameters and Methods for Determining Condensation Heat Transfer to Containment Structures, J. Green and K. Almenas; DESIGN FEATURES: 49 Modem Tornado Design of Nuclear and Other Potentially Hazardous Facilities, J. D. Stevenson and Y. Zaho; U.S. NUCLEAR REGULATORY COMMISSION INFORMATION AND ANALYSES: 73 1994 Accident Sequence Precursor Program Results, R. J. Belles, J. W. Cletcher, D. A. Coplnger, B. W. Dolan, J. W. Minarick, and P. D. O'Reilly; ANNOUNCEMENTS: 93 American Institute of Chemical Engineers (AlChE) Spring 1997 National Meeting; 94 European Safety and Reliability Association International Conference on Safety and Reliability ESREL ’97; 95 Criticality Safety Challenges in the Next Decade; 96 21st International Symposium on the Scientific Basis for Nuclear Waste Management; 84 The Authors; 88 Letter to the Editor; 90 Indexes to Nuclear Safety, Volume 36.

05 NUCLEAR FUELS↗

DOE OSTI2015

Efficient and dynamic nuclear localization of green fluorescent protein via RNA binding

Classical nuclear localization signal (NLS) sequences have been used for artificial localization of green fluorescent protein (GFP) in the nucleus as a positioning marker or for measurement of the nuclear-cytoplasmic shuttling rate in living cells. However, the detailed mechanism of nuclear retention of GFP-NLS remains unclear. Here, we show that a candidate mechanism for the strong nuclear retention of GFP-NLS is via the RNA-binding ability of the NLS sequence. GFP tagged with a classical NLS derived from Simian virus 40 (GFP-NLS{sup SV40}) localized not only in the nucleoplasm, but also to the nucleolus, the nuclear subdomain in which ribosome biogenesis takes place. GFP-NLS{sup SV40} in the nucleolus was mobile, and intriguingly, the diffusion coefficient, which indicates the speed of diffusing molecules, was 1.5-fold slower than in the nucleoplasm. Fluorescence correlation spectroscopy (FCS) analysis showed that GFP-NLS{sup SV40} formed oligomers via RNA binding, the estimated molecular weight of which was larger than the limit for passive nuclear export into the cytoplasm. These findings suggest that the nuclear localization of GFP-NLS{sup SV40} likely results from oligomerization mediated via RNA binding. The analytical technique used here can be applied for elucidating the details of other nuclear localization mechanisms, including those of several types of nuclear proteins. In addition, GFP-NLS{sup SV40} can be used as an excellent marker for studying both the nucleoplasm and nucleolus in living cells. - Highlights: • Nuclear localization signal-tagged GFP (GFP-NLS) showed clear nuclear localization. • The GFP-NLS dynamically localized not only in the nucleoplasm, but also to the nucleolus. • The nuclear localization of GFP-NLS results from transient oligomerization mediated via RNA binding. • Our NLS-tagging procedure is ideal for use in artificial sequestration of proteins in the nucleus.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2016

Imaging analysis of nuclear antiviral factors through direct detection of incoming adenovirus genome complexes

Recent studies involving several viral systems have highlighted the importance of cellular intrinsic defense mechanisms through nuclear antiviral proteins that restrict viral propagation. These factors include among others components of PML nuclear bodies, the nuclear DNA sensor IFI16, and a potential restriction factor PHF13/SPOC1. For several nuclear replicating DNA viruses, it was shown that these factors sense and target viral genomes immediately upon nuclear import. In contrast to the anticipated view, we recently found that incoming adenoviral genomes are not targeted by PML nuclear bodies. Here we further explored cellular responses against adenoviral infection by focusing on specific conditions as well as additional nuclear antiviral factors. In line with our previous findings, we show that neither interferon treatment nor the use of specific isoforms of PML nuclear body components results in co-localization between incoming adenoviral genomes and the subnuclear domains. Furthermore, our imaging analyses indicated that neither IFI16 nor PHF13/SPOC1 are likely to target incoming adenoviral genomes. Thus our findings suggest that incoming adenoviral genomes may be able to escape from a large repertoire of nuclear antiviral mechanisms, providing a rationale for the efficient initiation of lytic replication cycle. - Highlights: • Host nuclear antiviral factors were analyzed upon adenovirus genome delivery. • Interferon treatments fail to permit PML nuclear bodies to target adenoviral genomes. • Neither Sp100A nor B targets adenoviral genomes despite potentially opposite roles. • The nuclear DNA sensor IFI16 does not target incoming adenoviral genomes. • PHF13/SPOC1 targets neither incoming adenoviral genomes nor genome-bound protein VII.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2014

Working Party on International Nuclear Data Evaluation Cooperation (WPEC)

The OECD Nuclear Energy Agency (NEA) is organizing the cooperation between the major nuclear data evaluation projects in the world. The NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC) was established to promote the exchange of information on nuclear data evaluation, measurement, nuclear model calculation, validation, and related topics, and to provide a framework for cooperative activities between the participating projects. The working party assesses nuclear data improvement needs and addresses these needs by initiating joint activities in the framework of dedicated WPEC subgroups. Studies recently completed comprise a number of works related to nuclear data covariance and associated processing issues, as well as more specific studies related to the resonance parameter representation in the unresolved resonance region, the gamma production from fission-product capture reactions, the U-235 capture cross-section, the EXFOR database, and the improvement of nuclear data for advanced reactor systems. Ongoing activities focus on the evaluation of Pu-239 in the resonance region, scattering angular distribution in the fast energy range, and reporting/usage of experimental data for evaluation in the resolved resonance region. New activities include two new subgroups on improved fission product yield evaluation methodologies and on modern nuclear database structures. Future activities under discussion include a pilot project of a Collaborative International Evaluated Library (CIELO) and methods to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data. In addition to the above mentioned short-term, task-oriented subgroups, the WPEC also hosts a longer-term subgroup charged with reviewing and compiling the most important nuclear data requirements in a high priority request list (HPRL).

99 GENERAL AND MISCELLANEOUS↗

DOE OSTI2025

Advancing International Integration and Strengthening Responsible Peaceful Uses of Nuclear Applications Through Specialized Curriculums

Nuclear technology has been pivotal in addressing some of the most pressing global challenges, ranging from energy production to combatting infectious diseases to agricultural security. Oak Ridge National Laboratory (ORNL), as a leader in nuclear research and development including in the field of radioisotopes, is well situated to share lessons learned and enhance global collaboration from years of discoveries in the field. Accordingly, the U.S. Department of Energy’s National Nuclear Security Administration (NNSA) sponsors specialized educational programs at ORNL, with support from the IAEA, focused on advancing peaceful nuclear applications and associated industries while upholding strong nuclear safety, security, and safeguards standards. The Joint U.S./IAEA International School on Peaceful Uses of Nuclear Applications, launched in 2024, is a cornerstone of this collaboration. The school provides an opportunity for early-career professionals from around the globe to gain practical knowledge and skills in utilizing nuclear technologies for peaceful purposes. This initiative demonstrates the United States’ commitment to its obligations under the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), specifically Article IV, which calls on nuclear-weapon states to facilitate access to the peaceful uses of nuclear energy while guarding against the proliferation of nuclear weapons. In this paper, we explore the curriculum, objectives, and global impact of the program. Participants of the ICARST-2025 conference are invited to learn more about this program, contribute to its development, and explore opportunities for collaboration. This school exemplifies how strategic partnerships, and educational initiatives can drive the peaceful and beneficial use of nuclear technology worldwide

Raffo Caiado, Ana [ORNL] (ORCID:0009000239304805)↗