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Showing 1 to 16 of 16 for “"U-238"”.
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A one-dimensional fuel burnup model of a PWR
… The isotopes considered were U-235, Pu-239, U-238, Xe-135, I-135, Sm-149, Pm-149 and the lumped burnable poison isotope. The flux was approximated by the sum of two trigonometric functions. The magnitude and shape of the flux were determined by holding power constant, constraining system to be …
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A new unresolved resonance region methodology
… cross-section factor probability tables for U-238 that were found to be in agreement with current standards. The modified U-238 probability tables were shown to produce k-eff results in excellent agreement with several standard benchmarks, including the IEU-MET-FAST-007, IEU-MET-FAST-003, and …
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Performance analysis of functional expansion tallies on 2D PWR pin cell
… of certain reaction rates, such as U-238 absorption. A generalized functional expansion method using an arbitrary series of independent functions as basis set is then proposed and tested. To capture the self-shielding effect of the U-238 absorption rate, an exponential basis set is …
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Evaluation of material attractiveness to non-state actors of various nuclear materials in Thorium fuel cycles
… of Pu-239 due to the neutron capture of U-238 in mixed lightly-enriched uranium (LEU)/Thorium fuels, are also causes for proliferation concern.
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Critical assessment of thorium reactor technology
… for proliferation concern) with U-236 and U-238. Several countries, including the USA, China, and India, are developing new conceptual designs which focus on the advantages offered by thorium. Thorium reactor technology today, as well as its practicality in the near-future, was surveyed to …
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Combining thorium with burnable poison for reactivity control of a very long cycle BWR
… the cycle. Since Th-232 functions more like U-238 than burnable poison, this limits the allowed thorium to extend discharge burnup. Since all fuel assembly designs in this study have the same target exposure of 15EFPY, the economic performance of each design can be compared based on the amount …
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Modeling the performance of high burnup thoria and urania PWR fuel
… Due to the lower build-up of Pu-239 (less U-238 in ThO₂-UO₂ fuel) and flatter distribution of U-233 (less resonance capture in Th-232), thoria fuel experiences a much flatter power distribution and thus has a less severe rim effect than UO₂ fuel. To model this effect properly, a new model, …
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Analysis of in-core experiment activities for the MIT Research Reactor using the ORIGEN computer code
… for ten individual elements (plus U-235 and U-238) that are commonly found in MITR in-core experiment (ICE) assemblies. The ORIGEN-S analyses for the ACI, HTIF, and EPRI ECP experiments produced results that were relatively similar to the results produced by previous analyses that utilized the …
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ADVANCED APPLICATIONS OF COSMIC-RAY MUON RADIOGRAPHY
… mass, U-235 could be differentiated from U-238 through muon induced fission.
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Safety implications of a sensitivity analysis of the reactor kinetics parameters for fast breeder reactors
… precursor group, resulting from the fission of U-238, producing neutrons in the first energy group. It was found, for example, that for a rod ejection time of 30 seconds, an uncertainty of 7.2% in the fast components of the spectra resulted in a 24% uncertainty in the predicted power and power …
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Reactor agnostic multi-group cross section generation for fine-mesh deterministic neutron transport simulations
… of 2D PWR benchmarks. Both schemes reduced U-238 capture rate errors by up to a factor of four with respect to schemes which neglect to model MGXS clustering. In addition, the schemes required an order of magnitude fewer MC particle histories to converge MGXS for multi-group deterministic …
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Evaluation of high power density annular fuel application in the Korean OPR-1000 reactor
… burnup curve. Fictitiously increasing U-238 number densities in CASMO-4 inputs by 10% produces good match with the MCNP-based burnup code, MCODE2.2. The whole core model of Ulchin Nuclear Unit 5 is established as a benchmark using SIMULATE-3 to calculate the steady state reactor core …
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The preparation and characterisation of highly selective adsorbents for fission product removal from acid solutions
… of reprocessing is to recover unused uranium (U-238 and U-235) and plutonium isotopes thereby preventing them from being wasted. This can save up to 30% of the natural uranium that is required each year for the fabrication of new nuclear fuel. A second aim is to reduce the volume of high-level …
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Fertile free fuels for plutonium and minor actinides burning in LWRs
… of initial loadings and burning rate. Lack of U-238 and the neutronic characteristics of plutonium lead to degradation of safety related kinetic parameters. It is found that various inert matrix fuels have similar values for the Doppler coefficient, moderator temperature coefficient, void …
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The Calibration of a Fission Chamber at 14 MeV: Accelerator based Neutron Beam Detection
A presently uncalibrated fission chamber for use at Lawrence Livermore National Laboratory and Lawrence Berkeley National Laboratory was evaluated for functionality and will be cross-calibrated for neutron detection against a known fission chamber at Ohio University. The 4-MV Tandem Van De Graaff …
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Mineralogical and geochemical characterisation of phosphogypsum waste material and its potential for use as backfill at WMC Fertilizers' Mine site, Phosphate Hill, N-W Queensland
… common. Radiochemical analyses have identified U-238, Po-210, Pb-210, Ra-226 and Rn-222 as being present in the ore and throughout the manufacturing process. All are present to varying degrees in the PG but the U-238 tends to partition more into the fertilizer. None of the radionuclides occur at …