Assessment of Occupation Radiation Exposure during Maintenance in ITER Upper Ports
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Harb, Moataz [ORNL] (ORCID:0000000200379087)↗
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Results for “Nuclear Fusion”
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Nuclear processes in the jets of SS433
The very narrow gamma-ray lines observed at 1.495 and 6.695 MeV from SS433 which are blueshifted 1.369 and 6.129 emissions from deexcitations of (24)Mg* and (16)O* in grains moving with the jets and inelastically excited by interactions with the ambient medium are discussed. Energetic particle interactions in grains produce very narrow gamma ray lines from deexcitation of nuclear levels whose lifetimes are long enough that the excited nuclei stop before deexcitation. The presence of grains in the jets resolves hitherto discussed difficulties of inelastic excitation models for gamma ray production in SS433, the very narrow widths of the observed lines and the absence of other strong lines, expected from abundant elements. A model is proposed which could be distinguished from a previously proposed fusion model by gamma ray line observations.
Ramaty, R.↗
Nuclear processes in the jets of SS 433
The very narrow gamma-ray lines observed at 1.495 and 6.695 MeV from SS 433 which are blueshifted 1.369 and 6.129 emissions from deexcitations of (24)Mg-asterisk and (16)O-asterisk in grains moving with the jets and inelastically excited by interactions with the ambient medium are discussed. Energetic particle interactions in grains produce very narrow gamma ray lines from deexcitation of nuclear levels whose lifetimes are long enough that the excited nuclei stop before deexcitation. The presence of grains in the jets resolves hitherto discussed difficulties of inelastic excitation models for gamma ray production in SS 433, the very narrow widths of the observed lines and the absence of other strong lines, expected from abundant elements. A model is proposed which could be distinguished from a previously proposed fusion model by gamma ray line observations.
Ramaty, R.↗
Pisces-RF: A helicon-plasma based linear-device for the study of fusion relevant plasma-materials-interactions
Not Available
36 MATERIALS SCIENCE↗
Digital Twin Enabling Technologies for Online Condition Monitoring of Nuclear Power Plant Components
Online condition monitoring is an area of active research that may enable improved scheduling, maintenance, and safety of nuclear power plant components, reducing unnecessary derate while simultaneously improving operational capacity. Digital twins are one avenue to conduct online condition monitoring and are currently being explored by national laboratories and universities alike. Digital twins for online condition monitoring are, in essence, state concurrent models that emulate a physical process which predicts a parameter and compares it against a measured value. However, digital twins may also provide additional insights by combining and interpreting various sources of information. These insights may be used for preventative maintenance scheduling optimization or early fault detection and are projected to be valuable for meeting requirements under 10 CFR 50.55a. However, digital twin technologies are still under significant development; quantifying model uncertainties, improving unique fault identification, and multimodal sensor fusion are some areas under investigation. Therefore, in this work, we discuss and review the various enabling technologies, in the form of advanced sensors, instrumentation, and modelling methods, that may be used to implement and enhance digital twins for online condition monitoring. A potential use case for pump-motors is presented to demonstrate how these various pieces of enabling digital twin technologies may integrated together for online condition monitoring. Challenges and opportunities associated with the pump-motor digital twin enabling technologies are also identified and discussed.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
Digital-Twin-Enabling Technologies for Online Condition Monitoring of Nuclear Power Plant Components
Online condition monitoring is an area of active research that may enable improved scheduling, maintenance, and safety of nuclear power plant components, reducing unnecessary derates while simultaneously improving operational capacity. Digital twins are one avenue to conduct online condition monitoring and are currently being explored by national laboratories and universities alike. Digital twins for online condition monitoring are, in essence, state concurrent models that emulate a physical process which predicts a parameter and compares it against a measured value. However, digital twins may also provide additional insights by combining and interpreting various sources of information. These insights may be used for preventative maintenance scheduling optimization or early fault detection and are projected to be valuable for meeting requirements under 10 CFR 50.55a. However, digital twin technologies are still under significant development; quantifying model uncertainties, improving unique fault identification, and multimodal sensor fusion are some areas under investigation. Therefore, in this work, we discuss and review the various enabling technologies, in the form of advanced sensors, instrumentation, and modelling methods, that may be used to implement and enhance digital twins for online condition monitoring. A potential use case for pump-motors is presented to demonstrate how these various pieces of enabling digital twin technologies may integrated together for online condition monitoring. Challenges and opportunities associated with the pump-motor digital twin enabling technologies are also identified and discussed.
22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
Measurements of the 27 Al(α,n) Thick Target Yield near Threshold
In this work, we present results from direct measurements of the 27 Al(α,n) thick-target yield from laboratory incident energies E α ≈ 3 to 5 MeV, performed with the 3 HeBF 3 Giant Barrel (HeBGB) neutron detector at the Edwards Accelerator Laboratory. Our measurements have a small energy cadence in order to address discrepancies and sparseness of thick-target-yield data sets existing for this energy region. We find general agreement with existing data sets, including yields derived from cross-section data, while resolving a discrepancy between existing thick-target-yield data sets for E α ≈ 4–5 MeV. However, for E α < 3.5 MeV, our results are substantially lower than previous thick-target-yield data and somewhat larger than yields calculated from existing cross-section data. Our data complete the energy range needed for estimates of the 27 Al(α,n) contribution to neutrino and dark matter detector backgrounds and result in increased viability of 27 Al(α,n) as a plasma diagnostic tool at fusion facilities such as the National Ignition Facility.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Three-dimensional reconstruction of laser-direct-drive inertial confinement fusion hot-spot plasma from x-ray diagnostics on the OMEGA laser facility (invited)
A deep-learning convolutional neural network (CNN) is used to infer, from x-ray images along multiple lines of sight, the low-mode shape of the hot-spot emission of deuterium–tritium (DT) laser-direct-drive cryogenic implosions on OMEGA. The motivation of this approach is to develop a physics-informed 3-D reconstruction technique that can be performed within minutes to facilitate the use of the results to inform changes to the initial target and laser conditions for the subsequent implosion. The CNN is trained on a 3D radiation-hydrodynamic simulation database to relate 2D x-ray images to 3D emissivity at stagnation. The CNN accounts for the lack of an absolute spatial reference and the different bands of photon energies in the x-ray images. While previous works studied the effect of mode-1 asymmetries on implosion performance using nuclear diagnostics, this work focuses on the effect of mode 2 inferred from x-ray diagnostics on implosion performance. A current analysis of 19 DT cryogenic implosions indicates there is an upper limit of ~20% reduction in the neutron yield caused by an ℓ = 2 amplitude for ℓ 2 /ℓ 0 ≤ 0.32. Here, these conclusions are supported by 2D simulations.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Particle control via cryopumping and its impact on the edge plasma profiles of Alcator C-Mod
At the high n e proposed for high-field fusion reactors, it is uncertain whether ionization, as opposed to plasma transport, will be most influential in determining n e at the pedestal and separatrix. A database of Alcator C-Mod discharges is analyzed to evaluate the impact of source modification via cryopumping. The database contains similarly-shaped H-modes at fixed I P = 0.8 MA and B t = 5.4 T, spanning a large range in P net and ionization. Measurements from an edge Thomson scattering system are combined with those from a midplane-viewing Ly α camera to evaluate changes to n e and T e in response to changes in ionization rates, S ion ∙ $n^{sep}_e$ and $T^{ped}_e$ are found to be most sensitive to changes to $S^{sep}_{ion}$, as opposed to $n^{ped}_e$ and $T^{sep}_e$. Dimensionless quantities, namely α MHD and v*, are found to regulate attainable pedestal values. Select discharges at different values of P net and in different pumping configurations are analyzed further using SOLPS-ITER. It is determined that changes to plasma transport coefficients are required to self-consistently model both plasma and neutral edge dynamics. Pumping is found to modify the poloidal distribution of atomic neutral density, n 0 , along the separatrix, increasing n 0 at the active X-point. Opaqueness to neutrals from high n e in the divertor is found to play a role in mediating neutral penetration lengths and hence, the poloidal distribution of neutrals along the separatrix. Pumped discharges thus require a larger particle diffusion coefficient than that inferred purely from 1D experimental profiles at the outer midplane.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Free-moving Quantitative Gamma-ray Imaging
The ability to map and estimate the activity of radiological source distributions in unknown three-dimensional environments has applications in the prevention and response to radiological accidents or threats as well as the enforcement and verification of international nuclear non-proliferation agreements. Such a capability requires well-characterized detector response functions, accurate time-dependent detector position and orientation data, a digitized representation of the surrounding 3D environment, and appropriate image reconstruction and uncertainty quantification methods. We have previously demonstrated 3D mapping of gamma-ray emitters with free-moving detector systems on a relative intensity scale using a technique called Scene Data Fusion (SDF). Here we characterize the detector response of a multi-element gamma-ray imaging system using experimentally benchmarked Monte Carlo simulations and perform 3D mapping on an absolute intensity scale. We present experimental reconstruction results from hand-carried and airborne measurements with point-like and distributed sources in known configurations, demonstrating quantitative SDF in complex 3D environments.
47 OTHER INSTRUMENTATION↗
Corrugated Feedhorn Arrays by Additive Manufacturing
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36 MATERIALS SCIENCE↗
Automated Bayesian high-throughput estimation of plasma temperature and density from emission spectroscopy
Here, this paper introduces a novel approach for automated high-throughput estimation of plasma temperature and density using atomic emission spectroscopy, integrating Bayesian inference with sophisticated physical models. We provide an in-depth examination of Bayesian methods applied to the complexities of plasma diagnostics, supported by a robust framework of physical and measurement models. Our methodology is demonstrated using experimental observations in the field of magneto-inertial fusion, focusing on individual and sequential shot analyses of the Plasma Liner Experiment at LANL. The results demonstrate the effectiveness of our approach in enhancing the accuracy and reliability of plasma parameter estimation and in using the analysis to reveal the deep hidden structure in the data. This study not only offers a new perspective of plasma analysis but also paves the way for further research and applications in nuclear instrumentation and related domains.
Bayesian inference↗
Boson Fermion Nuclei Stellar Nucleosynthesis: Monograph #7
Stellar nucleosynthesis is generally described as the process by which nuclei are combined through fusion to create larger nuclei by the specific addition of nucleons, leading to a stable nucleus of a higher positive charge (Z) or nucleon number (A), or both. By contrast, the boson fermion nucleus (BFN) attributes the creation of nuclei to highly chaotic processes within a star. Under high pressure and temperature within the star, and given a certain probability of overcoming coulomb barriers, nucleons and first-period nuclear components agglomerate in a manner that rarely results in a stable nuclear structure. On a random basis, proto-nuclei are conveyed out of the star’s central agglomeration zone in an upwelling flow from within the star. As these proto-nuclei evolve to their lowest energy state, they shed nucleons and undergo radioactive decay, emerging as a stable BFN structure.
07 ISOTOPE AND RADIATION SOURCES↗
Development of an accelerated creep testing technique via multi-specimen loading
This report summarizes a research effort undertaken by Argonne National Laboratory to accelerate the development of creep data package for code qualification. The goal is to explore new creep testing techniques to shorten the overall time needed to generate high-quality data to support an ASME code case on laser powder bed fusion 316H stainless steel. Progresses on the design and implementation of a 3-specimen load train and an innovative strain measurement method with direct potential current drop (DCPD) technique are reported.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
The ASD Scorpius Accelerator at the NNSS. Recruitment Slides for the University of Nevada, Reno [Slides]
The Scorpius Accelerator: Supports the maintenance of the US nuclear stockpile, helps the US not return to nuclear testing, is one of four diagnostics being installed 963 feet below ground, probes subcritical implosions of nuclear material, and supports the validation of LANL and LLNL computer codes. We are searching engineers and scientists with experienced in: Mechanical Engineering, Electrical Engineering, Pulsed Power, Plasma Physics, Controls, Diagnostics, and Fluids and pressure systems.
42 ENGINEERING↗
Nuclear Data Sheets for A=245
Available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass numbers A=245 have been compiled and evaluated. In this work, the adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data, are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are utilized. Unexpected or discrepant experimental results are also noted. Since the last evaluation, new rotational bands in 245 Pu have been observed to high spin from transfer reaction 244 Pu( 209 Bi, 208 Biγ) by 2014Ho16. While in 245 Am, the 249 Bk α decay measurements by 2013Ah03 added a new rotational band based on π3/2[521] configuration. The 245 Pu β - decay scheme is basically what was proposed in the late 60's and 47 γ rays have still not been placed. In 245 Cm, precise alpha energies and intensities were measured by 2015Ah03 in 249Cf α decay. Their reported alpha energies of the main α group were about 2 keV lower than in the previous evaluation. The spin and parity of the g.s. of 245 Es is still ambiguous as more detailed information on the decay is needed. With the production of 249 No via fusion evaporation reaction by groups in Dubna and GSI, it's alpha decay was studied and some properties of the daughter 245 Fm were published and included in this evalaution. Information on the other nuclides is scarce and not much has been investigated since the last evaluation. A summary and compilation of the discovery of the various nuclides in this mass region is given in: 2013Fr02 ( 245 Pu, 245 Am, 245 Cm, 245 Bk, 245 Cf), 2011Me01 ( 245 Es), and 2013Th02 ( 245 Md, 245 Fm).
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Prompt-delayed γ-ray spectroscopy of neutron-rich 119.121 In isotopes
The Z = 50 shell closure, near N = 82, is unique in the sense that it is the only shell closure with the spin-orbit partner orbitals, π g 9 / 2 and π g 7 / 2 , enclosing the magic gap. The interaction of the proton hole/particle in the above-mentioned orbitals with neutrons in the νh 11/2 orbital is an important prerequisite to the understanding of the nuclear structure near N = 82 and the νπ interaction. To explore the structural similarity between the high-spin isomeric states in In ( Z = 49), Sn ( Z = 50), and Sb ( Z = 51) isotopes from a microscopic point of view. In addition, to understand the role of a proton hole or particle in the spin-orbit partner orbitals, π g 9 / 2 and π g 7 / 2 , respectively, with neutron holes in the ν h 11 / 2 orbital on these aforementioned isomers. The fusion and transfer induced fission reaction Be 9 ( U 238 , f ) with 6.2 MeV/u beam energy, using a unique setup consisting of AGATA, VAMOS++, and EXOGAM detectors, was used to populate through the fission process and study the neutron-rich In 119 , 121 isotopes. This setup enabled the prompt-delayed γ -ray spectroscopy of isotopes in the time range of 100 ns – 200 μ s . In the odd- A In 119 , 121 isotopes, indications of a short half-life 19/2 - isomeric state, in addition to the previously known 25/2 + isomeric state, were observed from the present data. Further, new prompt transitions above the 25/2 + isomer in In 121 were identified along with reevaluation of its half-life. The experimental data were compared with the theoretical results obtained in the framework of large-scale shell-model calculations in a restricted model space. Furthermore, the ( π g 9 / 2 ν h 11 / 2 ; I | H ^ | π g 9 / 2 ν h 11 / 2 ; I ) two-body matrix elements of residual interaction were modified to explain the excitation energies and the B ( E 2) transition probabilities in the neutron-rich In isotopes. The (i) decreasing trend of E (29/2 + ) - E (25/2 + ) in odd-In (with dominant configuration π g 9 / 2 - 1 ν h 11 / 2 - 2 and maximum aligned spin of 29/2 + ) and (ii) increasing trend of E (27/2 + ) - E (23/2 + ) in odd-Sb (with dominant configuration π g 7 / 2 + 1 ν h 11 / 2 - 2 and maximum aligned spin of 27/2 + ) with increasing neutron number could be understood as a consequence of hole-hole and particle-hole interactions, respectively.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Variance Reduction within Implicit Monte Carlo Thermal Radiation Transport using the Local Importance Function Transform [Slides]
System of equations derived by Fleck and Cummings to model time-dependent thermal radiative transfer (TRT) problems: Solution of radiation specific intensity (I), non-linearly coupled to material internal energy (U); Absorption and re-emission approximated by effective scattering events. Useful for high-energy density physics simulations: i.e., astrophysics, inertial confinement fusion (ICF). Whereas deterministic methods are fully discretized and free of statistical noise, Monte Carlo methods allow for dynamic sampling of the phase space at the price of statistical noise; Monte Carlo methods are also characterized by a slow $\frac{1}{√Ν}$ convergence rate.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗