Abstract USNC-Technologies (USNC-Tech) is an advanced nuclear company focused on developing space nuclear power and propulsion systems to enable high-impact science missions and the growth of a self-sustaining in-space economy. As a subsidiary of Ultra Safe Nuclear Corporation (USNC), USNC-Tech has leveraged the technologies and experience gains from the design, licensing, and deployment of terrestrial

Abstract Nuclear thermal propulsion (NTP) provides a consistent source of thrust for long space missions. However, fuel development for NTP reactors is a major technological hurdle. Existing modeling and simulation tools developed by the U.S. Nuclear Engineering Advanced Modeling and Simulation (NEAMS) program for power reactors can be leveraged to help accelerate the fuel development. This work is

Abstract In this study, lattice physics calculations were carried out to evaluate the reactor physics characteristics of different advanced fuel lattices cooled with 7LiOH/NaOH or FLiBe and moderated externally by graphite and various types of metal hydroxides, such as 7LiOH, 7LiOD, Mg(OD)2, and ZrE(OD)4. The lithium in these compounds is enriched to 99.995 at. % 7Li/Li. Such lattice fuel concepts

Abstract Post Fukushima the U.S. Nuclear Regulatory Commission issued an Order on Spent Fuel Instrumentation (EA-12-051) requiring all U.S. nuclear plants to install spent fuel pool (SFP) water level monitoring instrumentation and ensure the instrument would remain functional following a safe shutdown earthquake (SSE). The structural integrity analysis requires an assessment of the hydrodynamic loads

Abstract Natural circulation, mixing, and stratification are important phenomena for the design and safety analysis of many advanced reactor designs with passive safety features as well as large open regions, such as pool reactor designs, spent fuel pools, and containments. Various modeling methods ranging from zero-dimensional (0-D) lumped volumes (or perfect mixing) to full three-dimensional (3-D)

Abstract How does naming an object affect the way it is or could be managed? This paper examines and compares classification systems for radioactive waste applied by the International Atomic Energy Agency (IAEA) and in France, Canada, and Belgium. I analyze how the relevant actors classify radioactive objects, and in so doing, prescribe their management. By comparing and describing four established

Abstract In the prototype fast breeder reactor Monju, fixed absorber worth was measured as the difference of core reactivity measured by control rod worth between cores with and without a single fixed absorber or three fixed absorbers. In this paper, the measurements are evaluated in detail, and their reliability and usefulness as validation data are investigated through a comparison with calculations

(2021). Correction. Nuclear Technology: Vol. 207, No. 5, pp. 771-771.

Abstract This analytical study focuses on loading standardized transportation, aging, and disposal canisters (STADs) at commercial reactor sites and subsequent transportation, e.g., to a consolidated interim storage facility (CISF). Specifically, the amount of spent nuclear fuel (SNF) available to load into STADs with varying deployment dates is explored, and the scenarios are compared with a scenario

Abstract Radioisotope power systems (RPSs) have transformed our ability to explore the solar system. RPSs have been in existence for almost seven decades. Most missions have utilized 238Pu as the radioisotope of choice to generate electrical power and to produce heat for the operation and thermal management of spacecraft systems. In Europe, for the past decade 241Am has been selected for RPS research

Abstract A one-dimensional (1-D) thermal stratification (TS) model was recently developed in our research group to predict the TS phenomenon in pool-type sodium-cooled fast reactors. This paper performs uncertainty quantification (UQ) of the 1-D TS model to evaluate its performance by considering the aleatoric uncertainties that existed in the model parameters and to identify the plausible sources

Abstract The Middle East Technical University Defocusing Beamline (METU-DBL) is being constructed in order to perform single event effects tests for the electronic components in accordance with the European Space Agency (ESA) European Space Components Coordination (ESCC) No. 25100 standard. The aim of this beamline is to provide a suitable test area at the end of the beamline using the beam elements

Abstract Zirconium silicide (Zr3Si2) is a heavy reflector material particularly effective for application to a Gas-cooled Fast Reactor (GFR) such as the General Atomics Energy Multiplier Module (EM2) and Fast Modular Reactor (FMR). In this work, the manufacturability of a high-density Zr3Si2 compound, in the Zr3Si2 phase, was investigated using hot-pressing and spark-plasma-sintering methods. The microstructure

Abstract As future U.S. National Aeronautics and Space Administration (NASA) missions aim for destinations farther out into the solar system, space nuclear propulsion (SNP), and in particular nuclear thermal propulsion (NTP), is the only feasible near-term technology able to provide specific impulses of 900 s or greater and thrust in the range of tens of thousands of pounds. To maximize the success

Abstract Molten eutectic LiCl-KCl salt is a widely used electrolyte for electrorefining uranium from spent nuclear fuel. Due to the hygroscopic nature of this salt, such operations must be performed under controlled atmospheric conditions, and waste salts require careful storage to avoid deliquescence and corrosion of container materials. This study investigated a potential processing path for reducing

Abstract Nuclear thermal propulsion (NTP) demonstrated a reported technology readiness level of 5 during the work performed in the 1950s–1970s under the Rover program. This level of capability was achieved through the design, construction, and use of 22 experimental ground tests. These experiments served as testbeds for designs, materials, and instrumentation at prototypical NTP conditions. To continue

Abstract The operating environment of nuclear reactors imposes extreme challenges on the materials from which the structures within and surrounding the reactor are constructed. Understanding the effects of exposure to this environment is critical for ensuring the safe long-term operation of these reactors. The Grizzly and BlackBear codes are being developed to model the progression of aging mechanisms

Abstract Very few papers exist in the field of social sciences that follow and study nuclear infrastructure design projects from the inside. Such a perspective would make it possible to understand the mechanisms of their successes or difficulties at their very origin. At a time when high hopes are placed on civil nuclear energy to solve the climate issue, but when simultaneously, nuclear industry actors

Abstract Exposure to air can cause amine solutions in CANada Deuterium Uranium (CANDU) reactor secondary coolant circuit feed tanks to absorb carbon dioxide (CO2). Likewise, carbon dioxide can be absorbed directly into the amine-containing secondary coolant by air ingress during shutdown, lay-up, and startup. Sampling operations, including transferring the sample to the laboratory and subsequent analyses

Abstract Advanced reactor concepts span the spectrum from heat pipe–cooled microreactors, through thermal and fast molten-salt reactors, to gas- and salt-cooled pebble bed reactors. The modeling and simulation of each of these reactor types comes with their own geometrical complexities and multiphysics challenges. However, the common theme for all nuclear reactors is the necessity to be able to accurately

Abstract Solid waste samples consisting of shredded cellulose, coated with either mesoparticles of metallic salts or dried metal nitrate (lutetium, ytterbium, or depleted uranium) solutions, were generated to mimic solid nuclear waste. After burning these samples, the masses of the aerosolized metal cations were quantified by leaching them from air filters and analyzing the leachate with inductively

Abstract Drawing on 32 months of interview-based ethnographic fieldwork, this paper examines Finland’s “mankala” nuclear energy companies through the lens of anthropological theories of corporate form. Mankalas are limited liability companies run like zero-profit cooperatives that bring together consortia of Finnish corporations and municipal energy providers to purchase, finance, and share the output

Abstract The purpose of this paper is to show that the responsibility of Tokyo Electric Power Company Holdings, Inc. (TEPCO) was “economized” in the wake of the accident. It is argued that responsibility for the nuclear accident was mainly linked to economic responsibility, and that social and moral responsibility were consequently obscured by the financial accounting that followed the accident. This

Abstract The aging of electrical cables has been the subject of substantial research and development (R&D) projects performed by national and international laboratories, universities, and private organizations for many years. This R&D was conducted to develop guidance, equipment, and techniques to support aging management of in-service cables in industrial facilities such as nuclear power plants, research

Abstract In the early days of nuclear energy in Brazil, a reactor named Argonaut, designed at Argonne National Laboratory, reached criticality at the Institute of Nuclear Engineering (IEN). The presence of a nuclear research facility at the campus of Federal University of Rio de Janeiro is still a cause of concern with regard to the radiological safety of the surrounding community, even though this

Abstract This paper describes the parametric analysis of an optical fiber–based gamma thermometer (OFBGT) that is intended to be used to infer the power distribution in the Ohio State University Research Reactor (OSURR). The OFBGT measures the radial temperature difference ΔT between an optical fiber that is within the thermal mass and an optical fiber that is within the capillary tube that is attached

Abstract The security of nuclear power plants becomes an ever more important issue after the tragedy of the World Trade Center of New York City on September 11, 2000. Utilities around the world have significantly increased the resources used to enhance the security of nuclear power plants. In this study, a mathematical model based on Monte Carlo simulations is developed to calculate the probability

Abstract The development and qualification of nuclear thermal propulsion (NTP) fuel element technologies would be aided by an in-depth model of material response and failure modes at operating conditions. Integrated computational materials engineering techniques have the potential to provide such a model, as demonstrated here through three case studies focused on a tungsten–uranium mononitride (UN)

Abstract Whether to use highly enriched uranium (HEU) or low-enriched uranium (LEU) in space reactors is a highly debated topic. Most analyses focus on performance as the principal determinant of use, where HEU has inherent advantages. This paper identifies seven dimensions along which rigorous comparisons must be made to evaluate whether HEU or LEU is an appropriate enrichment level for space nuclear

Abstract Many initiatives intended to improve safety in nuclear facilities have used the concept of “safety culture,” which focuses on human and organizational factors and emphasizes the importance of the perceptions, interpretations, and behaviors of the individuals and groups within organizations. Particularly when it comes to risk management, it is widely believed that safety culture can be a used

Abstract Remote visual inspection is a common approach to understanding the health of key components and substructures within nuclear power plants, particularly in difficult to access and high dosage areas. Interpretation of inspection footage is a manually intensive procedure and challenges arise in localizing and dimensioning defects directly from a video feed, which may be subject to uncertainty

Abstract Sockeye is a heat pipe analysis application based on the Multiphysics Object-Oriented Simulation Environment (MOOSE) finite element framework. The primary purpose of Sockeye is to provide a transient heat pipe simulation tool to be used in the analysis of nuclear microreactor designs. Sockeye provides the capability to perform one-dimensional, two-phase, compressible flow simulation of a heat

Abstract The small modular reactor (SMR) is considered one of the important energy sources for the realization of the de-carbonated society, especially SMR types that have 10 MW or less thermal power, called a microreactor or very small modular reactor (vSMR). Toshiba Energy Systems & Solutions has initiated the development of a multipurpose vSMR as a distributed energy source since 2017 called MoveluXTM

Abstract Lattice physics and core physics studies have been carried out to investigate the reactor physics feasibility of destroying americium (Am) and curium (Cm) using special target fuel bundles in blanket fuel channels in a heterogeneous seed-blanket pressure tube heavy water reactor (PT-HWR) core fueled primarily with natural uranium. Results indicate that it should be feasible to achieve net-zero

Abstract Although η, the number of neutrons released per neutron absorbed in a 232Th-233U (thorium) fuel cycle, is greater than 2 in the thermal spectrum and therefore the possibility of breeding in a water-moderated reactor exists, it has been found difficult to achieve in practice. It is useful to relax the constraint for breeding and examine a thorium cycle for pressurized water reactors PWRs, denoted

Abstract This study characterizes a failed discharged fuel rod with 53 000 MWd/tonne U from a nuclear power plant in Korea. Chalk River Unidentified Deposits (CRUD) and the oxide layer were observed using an electron probe micro-analyzer (EPMA, SX-50 R, CAMECA, France) with wavelength dispersive (X-ray) spectroscopy. A normally irradiated cladding specimen was analyzed for comparison with the failed

Abstract Molten-salt reactors will likely require some level of irradiation testing as part of their licensing basis. An ideal experiment would consider the integrated effect of neutron flux and fission product generation in addition to circulating flow conditions. The feasibility of a natural-circulation irradiation salt loop in the Advanced Test Reactor (ATR) is assessed here. The flow is induced

Abstract The U.S. Nuclear Regulatory Commission’s functional containment concept provides advanced nuclear power plant designers with more flexibility in terms of the civil/structural design if the appropriate set of barriers for prevention of radioactive material release exist. Some of the conceptual advanced reactor structures, without the traditional pressure boundaries of large containment structures

Abstract The ability to identify features within finite element simulations and track them over time is necessary for understanding and quantifying complex behaviors as disparate as turbulent vortices in a flow field to microstructure evolution. We extend our previous research on feature identification in parallel unstructured meshes with the novel ability to maintain feature distinctness by dynamically

(2021). Foreword: Selected papers from the 16th International Topical Meeting on Probabilistic Safety Assessment and Analysis (PSA 2019) Nuclear Technology: Vol. 207, Selected papers from the 16th International Topical Meeting on Probabilistic Safety Assessment and Analysis (PSA 2019), pp. iii-iv.

Abstract This paper provides an overview of the U.S. Nuclear Regulatory Commission’s (NRC’s) project to develop a technical report summarizing the most important insights from its three State-of-the-Art Reactor Consequence Analyses (SOARCA) project uncertainty analyses (UAs). The NRC, with Sandia National Laboratories, has completed three UAs as part of the SOARCA project, for three different operating

Abstract An epoxy solidification method was developed and tested for volume reduction, homogeneity, and acceptance criteria such as leaching characteristics and compressive strength. It satisfied the acceptance criteria and confirmed excellent performance in terms of volume reduction and homogenization. An epoxy solidification system was developed to treat radioactive spent resins arising in nuclear

Abstract BISON is a nuclear fuel performance application built using the Multiphysics Object-Oriented Simulation Environment (MOOSE) finite element library. One of its major goals is to have a great amount of flexibility in how it is used, including in the types of fuel it can analyze, the geometry of the fuel being modeled, the modeling approach employed, and the dimensionality and size of the models

Abstract Small modular reactors (SMRs) are currently framed as a clean energy innovation with a vital role to play in decarbonizing power production. We review two popular sustainability transitions frameworks—strategic niche management and technological innovation systems— for case studies of analogous clean technology innovations. We focus on those that include policy-relevant recommendations that

Abstract Ensuring the thermal stability of heat-generating nuclear waste glass canisters in interim storage and the thermal stability of bentonite in the deep geological repository are crucial to preserving the function of the waste form. Yet thermal stability might be challenged by further heated air conditions and excessive heat load in the waste form, such that the maximum temperature would be higher

Abstract GOTHIC and RELAP5 have been coupled to model the containment and passive containment cooling system (PCCS) for the Korean advanced containment designs. In the coupled system, GOTHIC models the containment and the outer shell (mid tube wall to outside surface) of the PCCS heat exchanger tubes and RELAP5 models the inner shell (inside surface to mid tube wall) and the coolant loop to the external

Abstract National Security Presidential Memorandum-20 (NSPM-20) (Launch of Spacecraft Containing Space Nuclear Systems) provides updated guidelines for launch authorization for three categories of proposed launches of spacecraft with space nuclear systems: Federal Government civil space including the National Aeronautics and Space Administration (NASA), Federal Government defense and intelligence,

Abstract A recent American “mini-series” on Chernobyl, widely watched across the world, presented viewers with the concluding finding that this massive accident had occurred because the reactor design had inherent flaws; flaws that were known but not previously fixed because it was “cheaper” that way. The reactor design in question is the RBMK, and this paper will argue that this design was far from

Abstract Nuclear power plants (NPPs) require accurate measurement of mass flow rates. Advanced flowmeters have been widely applied in several current industries; however, the operating environment in NPPs is especially harsh because of high temperature, high radiation, and extremely corrosive conditions. Several of the advanced reactor designs, such as liquid sodium pool reactors and integral small

Abstract The safe operation of a nuclear power plant (NPP) can be guaranteed through the team effort of operators in the main control room (MCR). Among the various features, peer checks, concurrent verification, independent verification, and communication reconfirmation are major contributors to effective operations in the MCR. In the digital MCR environment of advanced NPPs, there are potential emerging

Abstract Efficient solution via Newton’s method of nonlinear systems of equations requires an accurate representation of the Jacobian, corresponding to the derivatives of the component residual equations with respect to the degrees of freedom. In practice these systems of equations often arise from spatial discretization of partial differential equations used to model physical phenomena. These equations

Abstract In the high-temperature reactor design, it is common practice to leave gaps between the graphite blocks of the reflectors to accommodate thermal dilatation and material swelling, as well as to provide an additional cooling source during operation. These gaps give rise to bypass flows entering the reactor core. The bypass flows can change friction factors and heat exchange coefficients obtained

Abstract A steam explosion can occur when molten corium falls from the reactor vessel into the water in the reactor cavity. While various research studies have been conducted on steam explosions following the free fall of molten corium in air before entering the water, steam explosions following submerged corium discharge under the ex-vessel cooling condition have received relatively little analysis

Abstract This paper presents an overview of Pronghorn, a multiscale thermal-hydraulic (T/H) application developed by Idaho National Laboratory and the University of California, Berkeley. Pronghorn, built on the open-source finite element Multiphysics Object-Oriented Simulation Environment (MOOSE), leverages state-of-the-art physical models, numerical methods, and nonlinear solvers to deliver fast-running

Abstract The Transient Reactor Test (TREAT) facility recently replaced the automatic reactor control system (ARCS). This paper discusses some of the enhancements that were made during the ARCS replacement such as calculations to take into account the nonadiabatic effects and increasing the dynamic range for power and period indication. This paper also discusses upgrades that had been planned but were

Abstract The SCALE code system developed at Oak Ridge National Laboratory includes state-of-the-art capabilities for radiation source term and radiation transport simulations that can be used in numerous applications, including dose rate analyses of complex consolidated interim storage facilities (CISFs). A licensed CISF could be used to store tens of thousands of tonnes of spent nuclear fuel discharged

Abstract This paper examines the Nuclear Regulatory Commission’s (NRC’s) pursuit of social science research that could inform the oversight of nuclear power plant management. Perhaps no nuclear regulator has been as supportive of research on the intersection of organizational factors and reactor safety or as cautious in applying those findings to its regulations. This dissonance was rooted in the NRC’s

Abstract With the increasing interest in sodium fast reactor technology, as seen by applications to the U.S. Nuclear Regulatory Commission for the OKLO Aurora plant, fuel testing for the TerraPower Traveling Wave Reactor, and the impending construction and startup of the versatile test reactor (VTR), a modernized, accelerated approach to fuel qualification is needed. To guide this effort, a Phenomena

Abstract Can predictive models develop cognizance or awareness of how they have been used? Can models detect if they are being manipulated or executed in nonauthorized manners? Can a software track information propagation through its subroutines to improve execution efficiency? Can this be achieved in a covert manner, i.e., avoiding the use of additional variables, additional lines of code, and conventional

Abstract The SCALE code system developed at Oak Ridge National Laboratory includes state-of-the-art capabilities for radiation source term and radiation transport simulations that can be used in numerous applications, including dose rate analyses of complex consolidated interim storage facilities (CISFs). A licensed CISF could be used to store tens of thousands of tonnes of spent nuclear fuel discharged