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DOE OSTI2025

Direct local parametrization of nuclear state densities using the back-shifted Bethe formula

Level densities are often parametrized using the back-shifted Bethe formula (BBF) for nuclei that possess experimental data for s-wave neutron resonance average spacings and a complete discrete level sequence at low excitation energies. However, these parametrizations require the additional modeling of the dependence of the spin-cutoff parameter on excitation energy. Here, in this work, we avoid the need to model the spin distribution of level densities by using the experimental data to parametrize directly the state densities, for which the BBF does not depend on the spin-cutoff parameter. This approach allows for a local parameterization of state densities that is independent of the spin-cutoff parameter. We provide these parameters in a tabulated form for applications in nuclear reaction calculations and for testing microscopic approaches to state densities.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2022

A Critical Review of Heat Pipe Experiments in Nuclear Energy Applications

This critical review provides heat pipe (HP) experimental data sets that contain pertinent information regarding nuclear technology that may be beneficial to researchers. Heat pipes have been shown to have a tremendously positive impact on nuclear technologies and will continue to become a more prevalent technology as more nuclear reactor concepts embrace this robust technology. Most previous reviews may focus on only a specific HP design or application, and some are backdated. Herein, this critical review extends previous efforts; integrates and summarizes previously reported HP experimental efforts; and provides updates with recently reported results in the literature for HPs in all nuclear-related applications, including space power (thermal radiators, core cooling, and electricity production), microreactors (emergency core cooling, hybrid control rods, and reactor core cooling), and HP involvement in other nuclear-related technologies (spent fuel pool cooling). The two main objectives of this critical review are (1) to facilitate the development of HP codes by outlining some of the existing experimental data sets to validate their codes and directing developers to these efforts and (2) to provide comprehensive information regarding the vast applicability of HPs used in the nuclear industry, including the theory of operation and limitations to supplement researchers in the development of new ideas for potential applications in nuclear-related technologies. The review clearly shows extensive and diverse experimental data sets for HPs developed under diverse testing conditions depending on the available nuclear application for validation purposes. Thus, this critical review is oriented to providing attention to the existing efforts rather than determining gaps in HP research.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2019

Electrical Arc Fault Particle Size Characterization

In this investigation a series of small-scale tests were conducted, which were sponsored by the Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research (RES) and performed at Sandia National Laboratories (SNL). These tests were designed to better understand localized particle dispersion phenomena resulting from electrical arcing faults. The purpose of these tests was to better characterize aluminum particle size distribution, rates of production, and morphology (agglomeration) of electrical arc faults. More specifically, this effort characterized ejected particles and high-energy dispersion, where this work characterized HEAF electrical characteristics, particle movement/distributions, and morphology near the arc. The results and measurements techniques from this investigation will be used to inform an energy balance model to predict additional energy from aluminum involvement in the arc fault. The experimental setup was developed based on prior work by KEMA and SNL for phase-to-ground and phase-to-phase electrical circuit faults. The small-scale tests results should not be expected to be scale-able to the hazards associated with full-scale HEAF events. Here, the test voltages will consist of four different levels: 480V, 4160V, 6900V and 10kV, based on those realized in nuclear power plant (NPP) HEAF events.

36 MATERIALS SCIENCE↗

DOE OSTI2023

NCERC Provides Unique Opportunities for University Student Researchers

Five students and one faculty member - sponsored by the Defense Nuclear Nonproliferation (DNN, NA 22) university consortia - visited the National Criticality Experiments Research Center (NCERC) in July of 2023 to measure radiation signatures from Category I Special Nuclear Material (SNM) in a week-long measurement campaign organized by staff at Los Alamos National Laboratory. Participants included University of Florida, University of Michigan, and University of Illinois-Champaign Urbana. The measurement campaign was organized on behalf of the Consortium for Monitoring, Testing, and Verification (MTV), the Nuclear Science and Security Consortium (NSSC), and the Consortium for Enabling Technologies and Innovation (ETI).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2019

Standardized verification of the C YCLUS fuel cycle simulator

Many nuclear fuel cycle simulators can analyze transitions from once-through to advanced nuclear fuel cycles. Verification studies compare various fuel cycle analysis tools to test agreement and identify sources of difference. A recent verification study, Feng et al. (2016) established transition scenario test case specifications and accordingly evaluated national laboratory nuclear fuel cycle simulators, DYMOND, VISION, ORION, and MARKAL. This work verifies the performance of C YCLUS , the agent-based, open-source fuel cycle simulator, using the test case specifications in Feng et. al. We report, C YCLUS demonstrates agreement with the results from the previous verification study. Minor differences reflect intentional, detailed material tracking in the C YCAMORE reactor module. These results extend the example results in Feng et al. to further enable future verification of additional nuclear fuel cycle simulation tools.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2018

Nuclear code case development of printed-circuit heat exchangers with thermal and mechanical performance testing

The U.S. Department of Energy has agreed to fund a three-year integrated research project to close technical gaps involved with compact heat exchangers to be used in nuclear applications. This paper introduces the goals of the project, the research institutions, and industrial partners working in collaboration to develop a draft Boiler and Pressure Vessel Code Case for this technology. Heat exchanger testing, as well as non-destructive and destructive evaluation, will be performed by researchers across the country to understand the performance of compact heat exchangers. Testing will be performed using coolants and conditions proposed for Gen IV Reactor designs. Preliminary observations of the mechanical failure mechanisms of the heat exchangers using destructive and non-destructive methods is presented. Unit-cell finite element models assembled to help predict the mechanical behavior of these high-temperature components are discussed as well. Performance testing methodology is laid out in this paper along with preliminary modeling results, an introduction to x-ray and neutron inspection techniques, and results from a recent pressurization test of a printed-circuit heat exchanger. The operational and quality assurance knowledge gained from these models and validation tests will be useful to developers of supercritical CO 2 systems, which commonly employ printed-circuit heat exchangers.

42 ENGINEERING↗

DOE OSTI2026

The Future Polarized Target Program at Jefferson Lab

Polarized targets have played a crucial role in Jefferson Lab's exploration of nuclear structure over the past four decades. The three original experimental halls have seen 19 separate installations of polarized solid or gas targets for use in the particle physics scattering experiments, and this trend will continue in the next decade. Five polarized target systems are in preparation for use at JLab in the coming years. Hall B will see the use of two solid polarized targets, one longitudinally polarized to the beam, the other transversely, as well as a novel 3He gas polarized target. In Hall C, new experiments will augment the tensor polarization in dynamically polarized solids. Plans are under development to bring a polarized solid target to Jefferson Lab's photon beam hall, Hall D, for the first time. To support these efforts, the JLab polarized target group is building a test laboratory to develop dynamic nuclear polarization techniques, as well as an apparatus to irradiate target material using electrons from JLab's injector test facility. In this talk, we will explore the development progress and plans for each of these efforts.

Maxwell, James [Thomas Jefferson National Accelera↗

DOE OSTI2017

Analyses Supporting Design Review of TREAT Multi-SERTTA Experiment Test Vehicle

The Transient Test Reactor (TREAT) Facility was designed to evaluate nuclear fuels and structural materials under simulated nuclear excursion and transient power/cooling mismatch situations that could be encountered in nuclear reactors [1]. It was historically operated from 1959 through 1994; ongoing activities at Idaho National Laboratory (INL) include resumption of transient testing capabilities to generate experimental data suitable to validate advanced modeling and simulation of these transient conditions, supporting current and next generation power reactor design and nuclear safety [2]. The resumption of transient testing requires new experiment vehicle designs to satisfy testing needs. The most developed experiment test vehicle candidate in TREAT’s arsenal will be the Multi-SERTTA (Static Environment Rodlet Transient Test Apparatuses) [3], which accommodates up to four concurrent rodlets under separate environmental conditions. An overview of the Multi-SERTTA, which would be placed at the center of the TREAT core during use, is shown in Figure 1. In the current design, all four rodlet test vessels are identical except for flux shaping collar material content to meet design needs. As the date rapidly approaches for TREAT restart, there is a need to have the Multi-SERTTA design approved and tested. Test experiments are an integral component of TREAT operations, and will be integrated among initial restart testing and supporting core reactor physics measurements. An integral step in finalization of any test vehicle design for TREAT is the hosting and resolution of a formal design review.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

DOE OSTI2025

Can Neutron Star Tidal Effects Obscure Deviations from General Relativity?

Abstract One of the main goals of gravitational-wave astrophysics is to study gravity in the strong-field regime and constrain deviations from general relativity (GR). Any such deviation affects not only binary dynamics and gravitational-wave emission but also the structure and tidal properties of compact objects. In the case of neutron stars, masses, radii, and tidal deformabilities can all differ significantly between different theories of gravity. Currently, the measurement uncertainties in neutron star radii and tidal deformabilities are quite large. However, much less is known about how the large uncertainty in the nuclear equation of state (EOS) might affect tests of GR using binary neutron star mergers. Conversely, using the wrong theory of gravity might lead to incorrect constraints on the nuclear EOS. Here, we study this problem within scalar–tensor (ST) theory. We apply the recently derived ℓ = 2 tidal Love numbers in this theory to parameter estimation of GW170817. Correspondingly, we test if physics beyond GR could bias measurements of the nuclear EOS and neutron star radii. We find that parameter inference for both the GR and ST cases returns consistent component masses and tidal deformabilities. The radius and the EOS posteriors, however, differ between the two theories, but neither is excluded by current observational limits. This indicates that measurements of the nuclear EOS may be biased and that deviations from GR could go undetected when analyzing current binary neutron star mergers.

79 ASTRONOMY AND ASTROPHYSICS↗

DOE OSTI2017

Experiments and Modeling to Support Field Test Design

Disposition of heat-generating nuclear waste (HGNW) remains a continuing technical and sociopolitical challenge. We define HGNW as the combination of both heat generating defense high level waste (DHLW) and civilian spent nuclear fuel (SNF). Numerous concepts for HGNW management have been proposed and examined internationally, including an extensive focus on geologic disposal (c.f. Brunnengräber et al., 2013). One type of proposed geologic material is salt, so chosen because of its viscoplastic deformation that causes self-repair of damage or deformation induced in the salt by waste emplacement activities (Hansen and Leigh, 2011). Salt as a repository material has been tested at several sites around the world, notably the Morsleben facility in Germany (c.f. Fahland and Heusermann, 2013; Wollrath et al., 2014; Fahland et al., 2015) and at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM. Evaluating the technical feasibility of a HGNW repository in salt is an ongoing process involving experiments and numerical modeling of many processes at many facilities.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2020

Neutronic Consideration of TREAT Facility Fuel SiC Recladding

The Transient Reactor Test (TREAT) Facility is an air-cooled reactor composed of graphite-urania fuel encapsulated in zirconium alloy canisters and surrounded by ~2 ft (~61 cm) of nuclear grade graphite. The primary role of TREAT is to provide in-pile nuclear-heated safety research via transient testing [1]. Benchmark efforts have demonstrated sensitivity of TREAT neutronics models to graphite cross section data and key neutron poisons found in the fuel assemblies [2]. During fabrication of TREAT fuel assemblies, a small concentration of boron was inadvertently introduced with variable concentration into the aggregate of fuel blocks prepared for TREAT use. The concentration of boron, and its respective uncertainty, represent the most sensitive component in a neutronics study; unfortunately, nothing can be done to reduce or otherwise mitigate its impact. Hydrogen in the fuel blocks reduces the mean free path of the core and its true quantity and uncertainty is approximated. The hydrogen remains from pitch binder used in the fuel fabrication process and was not completely released due to incomplete fuel graphitization. Destructive fuel testing is necessary to quantify the actual hydrogen content and to improve benchmark model quality. A third neutron poison of some significance is the hafnium impurity in the Zircaloy-3 (Zry-3) assembly cladding. The quantity of hafnium is expected to be within nominal manufacturing limits for nuclear grade zircaloy. Recladding the fuel assemblies with material that is less neutron absorbing is expected to benefit reactor neutron economy. Moreover, TREAT’s total transient energy is restricted based on the rate of Zry-3 oxidation in TREAT’s air coolant environment. Hence, cladding with more benign air reaction kinetics could dramatically uprate the facility’s experimental capability. Silicon carbide (SiC) has been proposed as a candidate material for recladding TREAT assemblies, as SiC/SiC demonstrate favorable properties within nuclear environments [3]. The current operational limits of TREAT are restricted by the oxidation of Zry-3. Change of the cladding to SiC could feasibly double the current temperature limitation. Recladding opportunities allow for previously damaged fuel assemblies to be returned to service, as Zry-3 is not commercially available. The initial effort required to consider proceeding with any recladding effort is to neutronically characterize key reactor parameters while replacing Zry-3 with SiC. A characterization summary, with respective results, is provided herein.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2019

Designing the Neutron Detector for the NEXUS Test Facility

The SuperCDMS dark matter experiment is commissioning a new test facility at Fermilab, NEXUS, capable of testing a new suite of detectors that promise to push to lower dark matter masses than has previously been achieved. These detectors use silicon and germanium, cooled to tens of mK, to measure small vibrations in the crystal lattice caused by very tiny energy deposits. A core capability of NEXUS test facility is to use a commercial neutron generator, coupled to an array of detectors behind the test facility, to calibrate the nuclear recoil energy scale of these detectors through neutron scattering. The response of silicon and germanium to nuclear recoils below 1 keV energy transfer is largely unknown. For dark matter models which are primarily interacting with the nucleus, calibration of this response will completely determine the dark matter sensitivity of the experiment. In this context, the proper design of the neutron tagging detector to be used in the test facility needs to be found. This work will include simulation of the detector behavior and work towards an optimization of the detector geometry based on measurement resolution and detection rate. In addition, prototype scintillators and photodetectors will be studied as candidate detector elements.

47 OTHER INSTRUMENTATION↗

DOE OSTI2019

New histone deacetylase inhibitors and anticancer agents from Curcuma longa

The aims of this study were to explore histone deacetylase inhibitory and antioxidant activities of curcuminoids as well as derivatives of curcumin. Curcumin (6), demethoxycurcumin (7), dihydrocurcumin (8), bisdemethoxycurcumin (9), and hydroxycurcumin (10) were isolated and tested against histone deacetylases in HeLa nuclear extract. Hydroxycurcumin (10) showed the best inhibition among the isolated compounds. Some curcumin derivatives were also prepared and tested. The potential derivatives were tested on five cancer cell lines. All compounds exhibited slightly weaker antiproliferative activities against cancer cells and less toxic to non-cancer cells than curcumin (6). The least toxic derivative (17) exhibited the best antiproliferative activity against human cervical cancer cell lines (HeLa) with the IC{sub 50} value of 4.69 ± 0.14 μM. The most active histone deacetylase inhibitor (19) showed the highest potency against human colon cancer cell lines (HCT116) and the selective binding to HDAC4 based on molecular docking experiments. Most derivatives possessed antioxidant activities superior to curcumin. The results suggested potential candidates for anticancer agents.

60 APPLIED LIFE SCIENCES↗

NASA NTRS2007

Nuclear Thermal Propulsion (NTP) Development Activities at the NASA Marshall Space Flight Center - 2006 Accomplishments

In 2005-06, the Prometheus program funded a number of tasks at the NASA-Marshall Space Flight Center (MSFC) to support development of a Nuclear Thermal Propulsion (NTP) system for future manned exploration missions. These tasks include the following: 1. NTP Design Develop Test & Evaluate (DDT&E) Planning 2. NTP Mission & Systems Analysis / Stage Concepts & Engine Requirements 3. NTP Engine System Trade Space Analysis and Studies 4. NTP Engine Ground Test Facility Assessment 5. Non-Nuclear Environmental Simulator (NTREES) 6. Non-Nuclear Materials Fabrication & Evaluation 7. Multi-Physics TCA Modeling. This presentation is a overview of these tasks and their accomplishments

Ballard, Richard O.↗

DOE OSTI2021

SMART-COM – Scalable Multi-Agent Adaptive Resolution Tools for Collaborative Outage Management

The purpose of this grant was to conduct scientific research and prototype applications to support NPP outage staff in their adaptive decision-making in efficient scheduling and resource allocation while preventing violation of safety technical specifications. The project contributed to scientific knowledge and engineering methods in (1) user interface design, (2) scheduling optimization and risk estimation, and (2) natural language processing that would benefit the nuclear power plants in minimizing schedule overruns and even unexpected shutdowns. The research team conducted site visits at a test reactor facility and an operating nuclear power plant to gather necessary information and inputs for research and development of a software application to support NPP staff in executing their outages. The final software application consisted of three modules. First, the natural language processing module supports interactive processing of technical documentation to build a database for outage staff to query non-permissible actions on system components. This module can alleviate outage staff from reviewing extensive documentation and minimize violation of technical specifications, especially in time-sensitive situations. Second, the schedule optimization module schedules outage activities and compute risk indices that outperform existing software and current practice. This module can reduce completion time of an outage that typically have too many activities for human to optimize based on current practice that does not apply the latest operations research. Finally, the visualization module presents progress and risk information of the overall outage and individual activities, as well as enabling access to the natural language processing and schedule optimization modules. This module can provide outage staff with situation awareness that are necessary to make risk-informed decisions in response to unexpected events during the execution of an outage.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2020

Establishing Maximal Core Excess Reactivity Envelope for TREAT Test Vehicle Insertion

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

NASA NTRS2008

Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

To support the eventual development of a nuclear thermal rocket engine, a state-of-the-art experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The test device simulates the environmental conditions (minus the radiation) to which nuclear rocket fuel components will be subjected during reactor operation. Test articles mounted in the simulator are inductively heated in such a manner as to accurately reproduce the temperatures and heat fluxes normally expected to occur as a result of nuclear fission while at the same time being exposed to flowing hydrogen. This project is referred to as the Nuclear Thermal Rocket Element Environment Simulator or NTREES. The NTREES device is located at the Marshall Space flight Center in a laboratory which has been modified to accommodate the high powers required to heat the test articles to the required temperatures and to handle the gaseous hydrogen flow required for the tests. Other modifications to the laboratory include the installation of a nitrogen gas supply system and a cooling water supply system. During the design and construction of the facility, every effort was made to comply with all pertinent regulations to provide assurance that the facility could be operated in a safe and efficient manner. The NTREES system can currently supply up to 50 kW of inductive heating to the fuel test articles, although the facility has been sized to eventually allow test article heating levels of up to several megawatts.

Emrich, William J., Jr.↗

DOE OSTI2020

NNSA GenScen 2.1 Methodology

Nuclear weapons stockpile planning is a complex process. The Non-Proliferation Treaty,' New START Treaty,2 DOE/NNSA, STRATCOM, Navy, Air Force, and Executive-Branch all have objectives that drive requirements for the types and quantities of nuclear weapons, which in turn drive how nuclear weapons are designed, manufactured, tested, maintained, deployed, transported, stored, retired, and ultimately dismantled. An estimated 200 distinct individuals contribute to the development, completion, and approval of this plan. And once that plan is completed, herein called the N NSA Program of Record (POR), ensuring that the plan is feasible — that the stockpile work can get done — ensures that the Nuclear Security Enterprise (NSE) can deliver the intended nuclear force posture.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗