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At least 1,585 records · Page 88

Analysis of the MST-16 crimp process on cold 304L stainless steel

The purpose of this report is to assess the quality of the MST-16 crimp process through a series of cold experiments and metallographic analyses. Common practice in MST-16 uses a mechanical crimp on 304L stainless steel tubes to prevent radioactive contamination from escaping the tube interior for a variety of experiments. The crimped tubes must pass a leak check to demonstrate their radiological safety. Cold (i.e. non-radioactive samples) 304L tube samples were tested using two different approved crimping devices to assess the quality of the crimps. Each crimp was leak checked, followed by destructive metallographic analysis to determine the quality of both the crimp equipment and procedures used by MST-16 personnel.

42 ENGINEERING↗

A Novel High Frequency, High Bandwidth, Three Phase Mach Zehnder Optical Data Link [Slides]

Inertial Confinement Fusion (ICF) produces high yield, high bandwidth signals that must be sent over large distances. A three phase Mach Zehnder modulator system helps resolve many of the issues faced with measuring these signals. This setup requires a three step reconstruction program. The testing results from OMEGA show this setup was successful and is ready for fielding at Inertial Confinement Fusion, including the National Ignition Facility (NIF).

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Neutron Spectrum Determination for the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) with a Multi-Sphere Spectrometer

This report presents the work that was performed to determine the neutron energy spectrum (spectrum) of the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) with a neutron Multi-Sphere Spectrometer (MSS). The spectrometer measurements were performed when the generator is in an INL Materials and Fuels Complex (MFC) laboratory. The measurements were used in a spectrum unfolding software to calculate the neutron spectrum. Based on initial testing of the MSS spectrometer and experience with the unfolding software, an MMRTG spectrum is reported and a justification for the spectrum is provided.

46 - INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AN↗

Nuclear Safety [Vol. 35, No. 1, January-June 1994]

Nuclear Safety is a review journal that covers significant developments in the field of nuclear safety. Its scope includes the analysis and control of hazards associated with nuclear energy, operations involving fissionable materials, and the products of nuclear fission and their effects on the environment. Primary emphasis is on safety in reactor design, construction, and operation; however, the safety aspects of the entire fuel cycle, including fuel fabrication, spent-fuel processing, nuclear waste disposal, handling of radioisotopes, and environmental effects of these operations, are also treated. Table of Contents for this issue follows. THE CHERNOBYL ACCIDENT: 1 Chernobyl Accident Management Actions, A. R Sich; GENERAL SAFETY CONSIDERATIONS: 25 The IAEA-ASSET Approach to Avoiding Accidents is to Recognize the Precursors to Prevent Incidents, F. Reisch; ACCIDENT ANALYSIS: 36 A Review of the Available Information on the Triggering Stage of a Steam Explosion, D. F. Fletcher; 58 Analysis and Modeling of Flow-Blockage-Induced Steam Explosion Events in the High-Flux Isotope Reactor, R. P. Taleyarkhan, V. Georgevich, C. W. Nestor, U. Gat, B. L. Lepard, D. H. Cook, J. Freels, S. J. Chang, C. Luttrell, R. C. Gwaltney, and J. Kirkpatrick; 74 An Analysis of Disassembling the Radial Reflector of a Thermionic Space Nuclear Reactor Power System, M. S. El-Genk and D. V. Paramonov; CONTROL AND INSTRUMENTATION: 86 Standards for High-Integrity Software, D. R. Wallace, D. R. Kuhn, L M. Ippolito, and L. Beltracchi; DESIGN FEATURES: 98 Adoption of New Design Features for the Next Generation Nuclear Power Reactors, L. S. Tong; 114 Review of Nuclear Piping Seismic Design Requirements, G. C. Slagis and S. E. Moore; ENVIRONMENTAL EFFECTS: 128 PC-Based Probabilistic Safety Assessment Study for a Geological Waste Repository Placed in a Bedded Salt Formation, S. A. Khan; OPERATING EXPERIENCES: 142 Managing Aging in Nuclear Power Plants: Insights from NRC’s Maintenance Team Inspection Reports, A. Fresco and M. Subudhi; 150 Reactor Shutdown Experience, Compiled by J. W. Cletcher; 153 Selected Safety-Related Events, Compiled by G. A. Murphy; RECENT DEVELOPMENTS: 158 Reports, Standards, and Safety Guides, D. S. Queener; 168 Proposed Rule Changes as of Dec. 31, 1993; ANNOUNCEMENTS: 177 Symposium on Radioactive and Mixed Waste—Risk as a Basis for Waste Classification; 177 1995 Incineration Conference 178 Ninth Power Plant Dynamics Control and Testing Symposium; 174 The Authors

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Polysiloxane Scintillators for Efficient Neutron and Gamma-Ray Pulse Shape Discrimination

Plastic scintillators based on thermoplastics, such as polystyrene and poly(vinyl toluene) (PVT), are capable of neutron and γ radiation detection via pulse shape discrimination (PSD) when overdoped with select fluorescent molecules. This class of plastic scintillator has been extensively studied but is limited to applications suitable for thermoplastics. For applications requiring flexibility, scintillators composed of elastomers, such as polysiloxanes, offer an alternative to PVT scintillators. Polysiloxane scintillators are inherently flexible and have a short processing time on the order of 3 h in air and equivalent or better detection capability at reduced doping concentration (<5 wt %). This work presents polysiloxane-based scintillators, containing only 1–5 wt % of 2,5 diphenyl-oxazole (PPO) or 9,9-dimethyl-2-phenyl-9H-fluorene (PhF) as primary dopants and 9,9-dimethyl-2,7-distyryl-9H-fluorene (SFS) as a wavelength shifter. A 5 wt % PPO polysiloxane sample had improved neutron and gamma ray PSD and comparable light yield than EJ-299-33 tested under the same conditions, i.e., figure of merit (FoM) of 1.33 ± 0.03 at 450 keV ee and light yield of 94% relative to EJ-299-33. The 5 wt % PhF-polysiloxane sample had a higher light yield, 144% of EJ-299-33 but lower FoM under the same conditions (FoM of 1.09 ± 0.03). Furthermore, this work highlights the potential of polysiloxanes as a matrix for PSD capable plastic scintillators.

36 MATERIALS SCIENCE↗

High pressure experimental investigation of clinopyroxene dissolution in a K-basaltic melt

Dissolution of clinopyroxene (cpx) in a K-basaltic melt from the Campi Flegrei Volcanic District (Italy) has been investigated through dissolution and dissolution-crystallization experiments at pressure of 0.8 GPa, superliquidus temperature of 1350 °C, and dwell times between 0.5 and 1 h. The obtained dissolution rates range from 7.9·10 –6 cm s –1 to 6.1·10 –6 cm s –1 as a function of dwell time. In the dissolution-crystallization experiment (1300 °C; 0.8 GPa; 2 h), the formation of overgrowth rims accompanied by new cpx crystals suggests that the injection of recharge magmas in basaltic reservoir may lead to inverse or oscillatory zonation. The interaction between cpx and K-basaltic melt at ~1570 °C was studied by in situ radiography using synchrotron radiation combined with the Paris-Edinburgh press. Here, this resulted in cpx resorption to occur depending on the temperature conditions with respect to the liquidus temperature of the cpx (T cpxL ). The calculated cpx dissolution rates are ~5·10 –3 cm s –1 at T ≤ T cpxL and ~ 3·10 –2 cm s –1 at T ≥ T cpxL . The role of crystal dissolution in the estimation of magma residence times has been also tested for a natural magmatic system by interpolating the dissolution rates (~10 –5 –10 –6 cm s –1 ) with the textural data of cpx phenocrysts from the Agnano-Monte Spina pyroclastic deposit at Campi Flegrei caldera (Campanian region, Italy). Results from calculations indicate that the time required for partial or complete resorption of phenocrysts varies from ~0.5 to ~40 h, and that the effect of crystal dissolution may be relevant to estimate magma residence times whether significant dissolution occurs during magma mixing processes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Observation of ionization trends in a laboratory photoionized plasma experiment at Z

We report experimental and modeling results for the charge state distribution of laboratory photoionized neon plasmas in the first systematic study over nearly an order of magnitude range of ionization parameter ξ ∝ F/N e . The range of ξ is achieved by flexibility in the experimental platform to adjust either the x-ray drive flux F at the sample or the electron number density N e or both. Experimental measurements of photoionized plasma conditions over such a range of parameters enable a stringent test of atomic kinetics models used within codes that are applied to photoionized plasmas in the laboratory and astrophysics. From experimental transmission data, ion areal densities are extracted by spectroscopic analysis that is independent of atomic kinetics modeling. The measurements reveal the net result of the competition between photon-driven ionization and electron-driven recombination atomic processes as a function of ξ as it affects the charge state distribution. Results from radiation-hydrodynamics modeling calculations with detailed inline atomic kinetics modeling are compared with the experimental results. There is good agreement in the mean charge and overall qualitative similarities in the trends observed with ξ but significant quantitative differences in the fractional populations of individual ions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Treatment of Prostate Cancer with CD46-targeted 225 Ac Alpha Particle Radioimmunotherapy

Radiopharmaceutical therapy is changing the standard of care in prostate cancer and other malignancies. We previously reported high CD46 expression in prostate cancer and developed an antibody–drug conjugate and immunoPET agent based on the YS5 antibody, which targets a tumor-selective CD46 epitope. Here, we present the preparation, preclinical efficacy, and toxicity evaluation of [ 225 Ac]DOTA-YS5, a radioimmunotherapy agent based on the YS5 antibody. [ 225 Ac]DOTA-YS5 was developed, and its therapeutic efficiency was tested on cell-derived (22Rv1, DU145), and patient-derived (LTL-545, LTL484) prostate cancer xenograft models. Biodistribution studies were carried out on 22Rv1 tumor xenograft models to confirm the targeting efficacy. Toxicity analysis of the [ 225 Ac]DOTA-YS5 was carried out on nu/nu mice to study short-term (acute) and long-term (chronic) toxicity. Biodistribution study shows that [ 225 Ac]DOTA-YS5 agent delivers high levels of radiation to the tumor tissue (11.64% ± 1.37%ID/g, 28.58% ± 10.88%ID/g, 29.35% ± 7.76%ID/g, and 31.78% ± 5.89%ID/g at 24, 96, 168, and 408 hours, respectively), compared with the healthy organs. [ 225 Ac]DOTA-YS5 suppressed tumor size and prolonged survival in cell line–derived and patient-derived xenograft models. Toxicity analysis revealed that the 0.5 μCi activity levels showed toxicity to the kidneys, likely due to redistribution of daughter isotope 213 Bi. [ 225 Ac]DOTA-YS5 suppressed the growth of cell-derived and patient-derived xenografts, including prostate-specific membrane antigen–positive and prostate-specific membrane antigen–deficient models. Overall, this preclinical study confirms that [ 225 Ac]DOTA-YS5 is a highly effective treatment and suggests feasibility for clinical translation of CD46-targeted radioligand therapy in prostate cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Reference solutions for linear radiation transport: the Hohlraum and Lattice Benchmarks

Radiation transport describes the propagation of energetic particles through space as they interact with a surrounding material medium. In a kinetic description, radiation transport is modeled by a radiation transport equation (RTE) that prescribes the density of the radiation in position-momentum phase space. The purpose of this dataset is to provide highly resolved solutions to two benchmark problems. These two benchmarks do not possess exact solutions; moreover, the construction of a manufactured solution may require a non-physical source that is not desirable, especially if it spoils the physical nature of the solution. Thus the goal of this computational study is to provide a highly resolved reference solution for testing newer, more cost efficient methods that are currently being developed in the research community.

97 MATHEMATICS AND COMPUTING↗

The Opus radiative opacity code, a new implementation of the super-transition array method

This report describes the development of our new radiative opacity code Opus, submitted as part of a 2020 Level 2 milestone requirement. This code aims to incorporate the capabilities in existing but separate opacity codes previously developed at LLNL (Opal, Topaz, and Tycho). The first phase in the development, which was to implement the super-transition (STA) method of Bar-Shalom and co-workers is now completed. In this work, we describe the underlying physics, implementation, usage, and regression testing as well as providing numerical examples for the opacity tables of boron, chromium, iron, and nickel. The latter are benchmarked against the LLNL legacy STA code Tycho, with an average absolute relative difference of ~1.5 and 0.5% for Planck and Rosseland opacity means, respectively. The cases where differences are larger are well understood in terms of numerical instabilities near discontinuities of the average degree of ionization inherent to the assumed opacity/equation-of-state model.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

RaDIATE Collaboration Thermal shock studies

As next-generation accelerator target facilities (High Energy Physics, Spallation Sources, ... ) become increasingly more powerful and intense, high power target systems face key technical challenges, such as radiation damage and thermal shock. Those ultimately degrade the performance and lifetime of targets and have been identified as the leading cross-cutting challenges of high-power target facilities. In order to operate reliable beam-intercepting devices in the framework of energy and intensity increase for next generation accelerators, the RaDIATE Collaboration (Radiation Damage In Accelerator Target Environment), established in 2012 and managed by Fermilab, brings together existing expertise in nuclear material and accelerator targets from 20 international institutions, including CERN, to execute a coordinated strategy for high power targetry R&D. In this context, several thermal shock studies were performed at CERN's HiRadMat (High-Radiation to Materials) facility, that took a key step towards improving our knowledge on target damage tolerance. The first experiment HRMT-24, supported by EURCARD2 and completed in 2015, successfully validated the Johnson-Cook strength model developed at SwRI on beryllium S200FH (used for beam window material), providing a better confidence in simulating the thermal shock response of current and future S200FH beryllium components. HRMT-43, supported by ARIES and completed in 2018, tested various materials (Be, C, SiC, Si, Ti and ceramic nanofiber). It was a first and unique test which included pre-irradiated specimens from high energy proton beam irradiation to identify thermal shock response differences between non-irradiated and previously irradiated materials. Real-time measurement of dynamic thermomechanical response of graphite helped to benchmark numerical simulations.

43 PARTICLE ACCELERATORS↗

Design and development of equi-atomic refractory High Entropy Alloys for use in radiation environments

Development of new structural materials that can withstand the extreme environments of nuclear reactors where the materials are exposed to high dose rate of ~ 30 200 dpa, high temperatures of the order of 500 1000 o C and tens of years of operation is vital for exploiting the “smallest carbon footprint energy source” to its fullest, in order to deal with the energy crisis worldwide. Recently, HEAs have shown superior irradiation properties over conventional alloys like higher resistance to defect formation, lower void swelling, limited irradiation hardening and higher microstructural stability under irradiation, making them potential structural material candidates for reactors. Proper characterization and testing of these materials are essential before they can replace the conventional alloys.

36 MATERIALS SCIENCE↗

Warpage-Resistant, Under-Extrusion-Free, High-Surface-Quality Additive Manufacturing Process for Polyethylene-Based Composite Radiation Shielding Material

Polyethylene (PE) is one of the best shielding materials for primary space radiation due to its high hydrogen content. For effective secondary neutron shielding, boron-rich fillers are incorporated to enhance performance. The semicrystalline nature and high thermal expansion coefficient of PE impede its adoption for in situ additive manufacture in space via the fused deposition modeling (FDM) 3D printing. Here, we developed an optimized PE blend to mitigate the effects of under-extrusion and warpage. Guided by studies on extrusion and warpage, we developed an optimal set of printing parameters for the proposed PE blend. The optimum PE blend─both in its pure form and when doped with fillers─has been tested on different FDM printers. The printed structures exhibit high and uniform density, smooth surfaces, no warpage, and competitive mechanical properties. The FDM-printed plates demonstrate efficient shielding from thermal neutrons, predicted via modeling and confirmed experimentally using extended Q-range small-angle neutron scattering.

additive manufacturing↗

Engineering lithium-ion battery cathodes for high-voltage applications using electromagnetic excitation

Microwave radiation (MWR), a type of electromagnetic excitation source, reduces the synthesis temperature and processing time for chemical reactions compared to traditional synthesis methods. Recently, we demonstrated that MWR can engineer ceramics with different crystal phases compared to traditional methods [ Journal of Materials Chemistry A 5 , 35 (2017)]. Here, we further apply the MWR-assisted technique to improve the electrochemical performance of LiCoO 2 cathodes by engineering TiO 2 and ZrO 2 ceramic coatings. Electrochemical tests suggest that the TiO 2 coating improves the rate capability of the LiCoO 2 electrode. Both TiO 2 and ZrO 2 coatings improve the high-voltage (4.5 V) cycling stability of LiCoO 2 . The capacity remaining is improved from 52.8 to 84.4% and 81.9% by the TiO 2 coating and the ZrO 2 coating, respectively, after 40 cycles. We compare these results with existing studies that apply traditional methods to engineer TiO 2 /ZrO 2 on LiCoO 2 , and find that the MWR-assisted method shows better performance improvement. X-ray photoelectron spectroscopy measurements suggest that the improved cycling stability arises from the formation of metal fluorides that protect the electrode from side reactions with electrolytes. This mechanism is further supported by the reduced Co dissolution from TiO 2 /ZrO 2 -coated LiCoO 2 electrode after cycling. This study provides a new toolbox facilitating the integration of many delicate, low melting point materials like polymers into battery electrodes.

25 ENERGY STORAGE↗

Upcoming MCNP6.3 ® Release: New Features and Improvements [Slides]

The latest version of the MCNP6.3 code will be done and released this year. Many new features, substantial improvements, and bugfixes have made their way into the code. Improved documentation, testing, and peripheral tools will also be delivered.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Standard Operating Procedure for Optimal Deployment of Meteorological Instrumentation Within the Solar Radiation Research Laboratory (BMS and RMS SOP)

The objective of the National Renewable Energy Laboratory's (NREL's) Solar Radiation Research Laboratory (SRRL) is to collect and use high-quality solar radiation data sets for research leading to the widespread adoption of solar technologies. To appropriately populate and track the diverse array of instruments at the NREL-SRRL, NREL has established a Standard Operating Procedure (SOP) for optimal instrument deployment within the SRRL for both the Baseline Measurement System (BMS) and the Research Measurement System (RMS). Using best practices methodologies, the NREL-SRRL maintains a varied and extensive array of solar monitoring equipment to test, evaluate, and characterize the solar sensors used by federal and international agencies as well as the solar industry to determine the solar resource. The SOP provides the industry with guidance for solar resource assessment and is used for procedures in the long-term continuous monitoring of legacy instruments alongside state-of-the-art instruments. Based on the SOP, instruments are annually evaluated for continued deployment. Instruments that do not meet the SOP criteria are decommissioned, and new instruments that meet the criteria are deployed. Streamlining and optimizing the use of this facility ensures that the lab continues to be a world-leading solar calibration and measurement facility.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Results for the Fourth Quarter Calendar Year 2022 Salt Solution Sample for Performance Assessment Analyses

In this Technical Report, the chemical and radionuclide contaminant results from the fourth quarter calendar year 2022 salt solution sample for Performance Assessment (PA) analyses are presented in tabulated form. The information from this characterization will be used by Savannah River Mission Completion (SRMC) for the transfer of aqueous waste to Tank 50 and the Saltstone Production Facility (SPF), where the waste will be treated and disposed in the Saltstone Disposal Facility. This Technical Report compares results, where applicable, to SPF Waste Acceptance Criteria (WAC) LIMITS and TARGETS that were established at the time the salt solution sample was obtained. The chemical and radionuclide contaminant results from the characterization of the fourth quarter calendar year 2022 sampling of salt solution sent to Z area were requested by SRMC personnel via a Technical Task Request (TTR). Details of the testing are presented in the Savannah River National Laboratory (SRNL) Task Technical and Quality Assurance Plan (TTQAP). This Technical Report is the TTR deliverable relating Salt Solution Analysis from the SRMC request.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Deterministic-Monte Carlo Hybrid Methods for Eigenvalue Sensitivity Coefficient Calculations [Slides]

Hybrid method was developed based on a need to generate accurate sensitivities for specified systems with CLUTCH. This new method provides improved sensitivities with HMF-028-001, specifically with 238 U in the large reflector region. With the importance of each voxel predetermined with the adjoint flux, the hybrid method is able to generate more accurate sensitivities. More testing is needed for other types of systems and materials (i.e., thermal and intermediate energy ranges and different moderators and reflectors). Initial results are very promising and continual development of the new hybrid method is currently in progress.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗