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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Design of a high-power compact SRF linac for industrial applications of e-beam irradiation

Fermilab has developed a novel concept for an industrial electron linac using Nb3Sn coating technology and conduction cooling. These conduction-cooled linacs can generate electron beam energies up to 10 MeV in continuous-wave operation and reach higher power (>=1 MW) by combing several modules. Compact and light enough to mount on mobile platforms, our machine is anticipated to enable new in-situ environmental remediation applications such as waste-water treatment for urban areas, X-ray medical device sterilization, and innovative pavement applications. We highlight a few aspects of a 1 MW design of such a machine in this paper. A detailed plan is in Dhuley et al. (2022) Phys. Rev. Accel. Beams 25, 041601.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Towards a Benchmark Experiment with the Compact Nuclear Power Source

The Compact Nuclear Power Source (CNPS) was a high-assay low enriched uranium (HALEU) tristructural isotropic (TRISO)-fueled, graphite-moderated microreactor constructed in 1987 at Los Alamos National Laboratory. The reactor, conceived as a power source for short-range radar stations, was designed to be "walk-away safe," and was cooled by heat pipes and ambient air. Though the project was formally cancelled after the fuel and moderator material had been received, its potential to meaningfully advance the body of critical and integral data was evident, and critical experiments with a mock-up of the reactor proceeded at TA-18 until its disassembly in 1991. The reflector and some components of the core would later go on to see service as part of the New Production Reactor Modular High-Temperature Gas-Cooled Reactor (NP-MHTGR) critical experiments. In light of the progress made by groups like Westinghouse and X-Energy towards contemporary graphite-moderated microreactors, the system remains an attractive candidate for the basis of a benchmark experiment even today. Uncertainties remain, however, in some features of the system–inconsistencies in the dimensions and composition of the reactor’s components as described in literature and implemented in current computational models. The identification, quantification, and to the extent possible, the minimization of these uncertainties is a crucial task on the path towards creating a benchmark based on the CNPS system. The present work seeks to initiate this process with a survey of available documentation and improvements to the accuracy of CNPS neutronics models.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Irradiated AGR 5/6/7 Compact 4-1-3 Examination Plan

This plan describes the post irradiation examination (PIE) activities to be performed by Oak Ridge National Laboratory (ORNL) on irradiated Compact 4-1-3 taken from the Advanced Gas Reactor (AGR) experiment, AGR 5/6/7. This work will be performed in accordance with the general objectives outlined in the AGR 5/6/7 PIE Plan and guidance in the ORNL PIE Statement of Work.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Compact and Handheld Radioisotope Imaging Systems for Bio-medicine*

Author: Andrew Weisenberger (Thomas Jefferson National Accelerator Facility) Thomas Jefferson National Accelerator Facility is a U.S. Department of Energy federally funded research and development center whose mission is to study quark gluon physics. The laboratory capitalizes on its unique technologies and expertise to explore ways of applying nuclear physics principles and technologies to societal needs. The Radiation Detector and Imaging Group, in collaboration with universities, industry and other government laboratories, has for several years been applying advances in nuclear physics detector technology to several applications, particularly in the development of compact and handheld nuclear imaging systems. I will provide a brief overview of Jefferson Lab and provide examples of how the group has leveraged nuclear physics to bring advances to nuclear medicine, medical research and plant biology. The group continues to develop medical devices based on both single photon emission computed tomography (SPECT) and positron emission tomography (PET), making use of technology originally developed for basic nuclear physics research. *Thomas Jefferson National Accelerator Facility is operated by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.

Weisenberger, Andrew↗
DOE OSTI2022

X-ray Computed Tomography of Irradiated and Unirradiated AGR-3/4 Compacts A preliminary examination

What? Performed X-ray CT (XCT) on irradiated AGR-3/4 compacts Apparatus design Imaging results Preliminary analysis Extruded kernels DTF Identification Areas of interest for further exploration Why? Can provide non-destructive 3D perspective to enhance/compliment current PIE Potentially better quantitative measurements of certain features Better means of understanding any spatial distribution(s)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2013

Compact Accelerator Design for a Compton Light Source

A compact electron accelerator suitable for Compton source applications is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. The design includes a KE=1.24 MeV low-emittance, optimized superconducting electron gun; a 25 MeV linac with multi-spoke 4.2 K superconducting cavities; and transport that combinesmagnetic longitudinal bunch compressor and transvese final focus. We report on the initial designs of each element, including end to end simulations with ASTRA and elegant, and expected beam parameters.

Satogata, T.↗
DOE OSTI2012

Thermal-hydraulics and safety analysis of sectored compact reactor for lunar surface power

The liquid NaK-cooled, fast-neutron spectrum, Sectored Compact Reactor (SCoRe-N 5) concept has been developed at the Univ. of New Mexico for lunar surface power applications. It is loaded with highly enriched UN fuel pins in a triangular lattice, and nominally operates at exit and inlet coolant temperatures of 850 K and 900 K. This long-life reactor generates up to 1 MWth continuously for {>=} 20 years. To avoid a single point failure in reactor cooling, the core is divided into 6 sectors that are neutronically and thermally coupled, but hydraulically independent. This paper performs a 3-D the thermal-hydraulic analysis of SCoRe--N 5 at nominal operation temperatures and a power level of 1 MWth. In addition, the paper investigates the potential of continuing reactor operation at a lower power in the unlikely event that one sector in the core experiences a loss of coolant (LOC). Redesigning the core with a contiguous steel matrix enhances the cooling of the sector experiencing a LOC. Results show that with a core sector experiencing a LOC, SCORE-N 5 could continue operating safely at a reduced power of 166.6 kWth. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2013

A physics study for negative void reactivity in compact supercritical CO{sub 2}-cooled fast reactor

A compact S-CO{sub 2}-cooled fast reactor which has negative Coolant Void Reactivity (CVR) has been investigated. A negative CVR is important for the gas cooled fast reactor as an inherent safety mechanism to prevent the sudden positive reactivity insertion when the loss of coolant accident happens. An alternative solution to reduce the CVR is investigated in this study by using O-17 instead of O-16 in UO{sub 2} fuel. By using O-17 in the fuel, it is found that the CVR can even be negative. Impacts of the radial reflector on the CVR are also evaluated for the small SCO{sub 2} cooled fast reactor in this study. We have considered a pure lead (Pb) reflector and a lead magnesium eutectic (LME) reflector as alternative radial reflectors of the S-CO 2-cooled fast reactor. It has been shown that, with the LME radial reflector, the CVR can be negative, while the pure lead reflector provides a slightly positive CVR. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Compact heat exchanger with alternating fluid channels

A compact heat exchanger is provided, in which multiple streams can flow within the same layer or layers, and different fluids may flow in alternating channels within the same layer as well as flowing in alternating layers. Having fluids in alternating channels—as compared to only alternating layers within the same layer—increases the direct surface area between the fluids (the primary surface area) for heat transfer, thereby increasing the rate and efficiency of heat transfer. Methods of making and using the heat exchanger are also provided.

Gadalla, Hani Ahmed↗
DOE OSTI2015

Dismantling of primary shielding with prototype machines in a compact sodium cooled reactor - 15463

The Compact Sodium Cooled Reactor Facility Karlsruhe (KNK), a prototype reactor to demonstrate the Fast Breeder Reactor Technology in Germany, was in operation from 1971 to 1991. The dismantling activities started in 1991. The project aim is the green field in 2020. Most of the reactor internals as well as the primary and secondary cooling loops have already been dismantled. The contaminated sodium inventory has already been disposed of completely. Only the highly activated reactor vessel shielding structures remain. Due to their high dose rates, these structures must be dismantled remotely. For the removal of the primary shielding of the reactor vessel, 12 stacked cast iron blocks with a total mass of 90 Mg and individual masses of up to 15.5 Mg, a remote-controlled multifunctional dismantling device (HWZ) was designed, manufactured and tested in a mock-up. Since it is not possible to remove the segments in one piece for offsite treatment, a special prototype band-saw (BWZ) had to be developed for sawing the segments both horizontally and vertically into smaller pieces. The resulting sub-segments are transferred directly into repository containers. After the successful approval of the test sequences by the authorities and intensive training of the operational staff, both prototype machines were installed inside the reactor building containment for final assembly. The dismantling started in 2013. The present paper covers the successful dismantling of the primary shielding as well as the experiences gained through the development, use and improvement of these prototype machines. (authors)

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2023

Compact, low power, high resolution ADC per pixel for large area pixel detectors

A compact ADC circuit can include one or more comparators, and a serial DAC (Digital-to-Analog) circuit that provides a signal to the comparator (or comparators). In addition, the ADC circuit can include a serial DAC redistribution sequencer that can provide a plurality of signals as input to the serial DAC circuit and is subject to a redistribution cycle and which receives as input a signal from a data multiplexer whose input connects electronically to an output of the comparator. The circuit can further include an ADC code register that provides an ADC output that connects electronically to the output of the comparator and the input to the data multiplexer. Shared logic circuitry for sharing common logic between pixels can be included, wherein the shared logic circuitry connects electronically to the data multiplexer and the ADC code register, wherein the shared logic circuitry promotes area and power savings for the pixel detector circuit.

Fahim, Farah↗
DOE OSTI2016

Synthesis and Characterisation of Nanostructured UO{sub 2} Compacts for Separate Effect Investigations

At high burn up nuclear fuel undergoes a significant restructuring, and in particular near the pellet edge, where large 10 μm UO{sub 2} grains of the fresh fuel fragment to yield a material with grain size of 100-300 nm and porosity up to 20%. This so-called 'High Burn up Structure (HBS)' has been investigated in the past to elucidate its morphology, grain size, crystal structure, thermal conductivity, hardness, etc.. Handling of spent fuel, however, is difficult due to its high radioactivity and the concomitant shielding needed to manipulate even the smallest samples. The establishment of a route to prepare a surrogate material closely mimicking the HBS morphology is an essential step, if all the details of this fascinating material are to be understood. Furthermore, preparation of dense bulk nanocrystalline UO{sub 2} as a function of grain size and porosity enables the effect of these crucial parameters to be distinguished, ultimately to provide a full insight into properties of HBS and their detailed assessment. We have successfully produced high density UO{sub 2} disks (φ = 4 mm, h= 1 mm) with grain sizes tunable in the 40 to 1000 nm range, from 10 nm UO{sub 2} powders generated by oxalate precipitation of UO{sub 2} from U(IV) solutions. Consolidation has been achieved using a specially constructed spark plasma sintering (SPS) unit housed in a radiological glovebox, which is equipped with a special die system incorporating SiC inserts to achieve pressures of 500 MPa. The latter innovation has reduced processing times and temperatures, which in turn limits grain growth, but still enabling fully dense compacts to be produced. These results now open the path to determine the potential effect of grain size on mechanical properties, thermal conductivity, irradiation damage (and its recovery), and gas (fission and helium) behaviour therein. Furthermore, using suitable pore formers, samples with controlled porosity to fully emulate the HBS in irradiated fuel can be prepared. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Irradiated AGR 5/6/7 Compact 5-6-2 Examination Plan

This plan describes the post irradiation examination (PIE) activities to be performed by Oak Ridge National Laboratory (ORNL) on irradiated Compact 5-6-2 taken from the Advanced Gas Reactor (AGR) experiment, AGR 5/6/7. This work will be performed in accordance with the general objectives outlined in the AGR 5/6/7 PIE Plan and guidance in the ORNL PIE Statement of Work.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Methodology to Account for Radiation and Temperature Influences on Optical Fibers compaction and Index of Refraction

The effects of radiation induced compaction and index of refraction change can cause significant drift in the measurements from intrinsic fiber optic temperature sensors. The work presented here aims to develop and test a methodology to measure these macroscopic properties that are responsible for the drift in order to correct the measurement. This report discusses the measurement methodology, theory, and sensor construction. Preliminary results from the first irradiation test using this sensor are provided here.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Reirradiation and Post-reirradiation Heating Tests of Loose AGR-2 TRISO Particles and AGR-3/4 Fuel Compacts

To address the lack of data on the behavior of short-lived fission products I-131 (t1/2 = 8.02 d) and Xe-133 (t1/2 = 5.24 d) in the TRISO fuel system, loose AGR-2 particles and kernels were reirradiated in NRAD and subjected to post-reirradiation heating in the FACS furnace. This provided data on the release of fission products from exposed kernels, and the results were used to establish FACS condensation plate collection efficiencies for temperatures of 1000, 1200, and 1400°C where previously, the only collection efficiencies were for 1600°C tests. These new collection efficiencies were then applied to the NRAD-FACS tests of entire AGR-3/4 fuel compacts. Understanding the relative behavior of short-lived I-131, for example, is important because it is a significant contributor to offsite dose during postulated accidents, and Xe-133 has previously been used as a conservative indicator of I-131 behavior. These data will be used to support refinement of fission product transport models and HTGR source-term analyses.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗