Abstract
Detailed calculations have been completed for the KUHFR with MEU (45%) fuel. These results reflect the direct substitution of 45% enrichment UAl{sub x}-Al fuel at a density of 16 g/cm{sup 3} uranium for the HEU (93%) fuel in the reference design. No other changes in the dimensions or design of the reactor are required. This study also includes two cases for LEU (20%) fuel which consider the feasibility of minor design changes in the fuel plates or fuel elements. The first LEU case has the clad thickness reduced from 0.045 cm to 0.038 cm with a corresponding increase in the fuel meat thickness, and the second case has a single fuel plate removed from both the inner and outer fuel elements to accommodate thicker fuel plates. In both LEU cases the fuel meat is U{sub 3}O{sub 8}-Al at 3.0 g/cm{sup 3} uranium. The water channel is 0.240 cm for each of the cases (reduced from 0.244 cm used in the earlier design). The diffusion theory neutronics models for the two cylinder core design use XY geometry to represent one quarter of the core with regionwise bucklings imposed for the axial dimension. Axial extrapolation lengths were determined from single cylinder RZ
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Woodruff, W L;
[1]
Mishima, K
[2]
- Argonne National Laboratory, Argonne, IL (United States)
- KURRI, Osaka (Japan)
Citation Formats
Woodruff, W L, and Mishima, K.
Neutronics and thermal-hydraulics analysis of KUHFR.
IAEA: N. p.,
1983.
Web.
Woodruff, W L, & Mishima, K.
Neutronics and thermal-hydraulics analysis of KUHFR.
IAEA.
Woodruff, W L, and Mishima, K.
1983.
"Neutronics and thermal-hydraulics analysis of KUHFR."
IAEA.
@misc{etde_20571736,
title = {Neutronics and thermal-hydraulics analysis of KUHFR}
author = {Woodruff, W L, and Mishima, K}
abstractNote = {Detailed calculations have been completed for the KUHFR with MEU (45%) fuel. These results reflect the direct substitution of 45% enrichment UAl{sub x}-Al fuel at a density of 16 g/cm{sup 3} uranium for the HEU (93%) fuel in the reference design. No other changes in the dimensions or design of the reactor are required. This study also includes two cases for LEU (20%) fuel which consider the feasibility of minor design changes in the fuel plates or fuel elements. The first LEU case has the clad thickness reduced from 0.045 cm to 0.038 cm with a corresponding increase in the fuel meat thickness, and the second case has a single fuel plate removed from both the inner and outer fuel elements to accommodate thicker fuel plates. In both LEU cases the fuel meat is U{sub 3}O{sub 8}-Al at 3.0 g/cm{sup 3} uranium. The water channel is 0.240 cm for each of the cases (reduced from 0.244 cm used in the earlier design). The diffusion theory neutronics models for the two cylinder core design use XY geometry to represent one quarter of the core with regionwise bucklings imposed for the axial dimension. Axial extrapolation lengths were determined from single cylinder RZ computations. The central test region in each cylinder contains a homogeneous representation of the upper irradiation baskets and the lower void mechanism with the void out. Burnup and temperature dependent cross-section data were generated using current ANL methods The fuel cycle models include fitted data for the changes in cross-sections with burnup. A cross-section library with 5 energy groups was used for most of the neutronics computations. For the change in reactivity with temperature, where more scattering detail was considered necessary, 10 energy groups were used. The boron loadings for the burnable poison in the sideplates were chosen to reduce the BOL excess reactivity to <8% for each model. This gives the desired shutdown margin of 4 with a control rod worth of 12% assumed for each case. The change in control rod worth with reduced enrichment has not yet determined, but only a small decrease in worth is expected. These BOL boron poisoned fuels are also used as the fresh fuel feed for the equilibrium fuel cycle studies contained in this report. The first three cases shown have matching cycle lengths in the equilibrium cycle, while the last case has a considerably longer cycle length. These results are similarly reflected in the 'Maximum Cycle Lengths' shown for unpoisoned BOL cores. Thus, the first three case can be considered comparable. The last case might be considered as an option for an extended cycle length design. The cycle length for this case is increased by about 21%. Obviously, by decreasing the uranium density in the fuel meat (to 2.7 g/cm{sup 3}), the cycle length for this design could be reduced to match that of the other cases. Thermal-hydraulic calculations have been carried out in order to study the safety aspects of the use of reduced enrichment uranium fuel for the KUHFR. The calculations were based on what is outlined in the Safety Analysis Report for the KUHFR and also the IAEA Guidebook for the RERTR program. Only a few combinations of hydraulic parameters have been tested because the reactor safety cannot be discussed without any nuclear physics considerations. For example, any variations in fuel coolant channels may change not only flow velocities but also power peaking factors which may affect the assessment of reactor safety. For this reason, the thermal-hydraulic calculations were carried out only for those specific cases on which neutronics analysis has been already performed. Low enriched uranium (LEU) cases are also included in this study as initial feasibility studies for potential conversion. The computer code PLTEMP has been developed to calculate the flow distribution in the core, fuel plate temperatures and DNB heat fluxes.}
place = {IAEA}
year = {1983}
month = {Aug}
}
title = {Neutronics and thermal-hydraulics analysis of KUHFR}
author = {Woodruff, W L, and Mishima, K}
abstractNote = {Detailed calculations have been completed for the KUHFR with MEU (45%) fuel. These results reflect the direct substitution of 45% enrichment UAl{sub x}-Al fuel at a density of 16 g/cm{sup 3} uranium for the HEU (93%) fuel in the reference design. No other changes in the dimensions or design of the reactor are required. This study also includes two cases for LEU (20%) fuel which consider the feasibility of minor design changes in the fuel plates or fuel elements. The first LEU case has the clad thickness reduced from 0.045 cm to 0.038 cm with a corresponding increase in the fuel meat thickness, and the second case has a single fuel plate removed from both the inner and outer fuel elements to accommodate thicker fuel plates. In both LEU cases the fuel meat is U{sub 3}O{sub 8}-Al at 3.0 g/cm{sup 3} uranium. The water channel is 0.240 cm for each of the cases (reduced from 0.244 cm used in the earlier design). The diffusion theory neutronics models for the two cylinder core design use XY geometry to represent one quarter of the core with regionwise bucklings imposed for the axial dimension. Axial extrapolation lengths were determined from single cylinder RZ computations. The central test region in each cylinder contains a homogeneous representation of the upper irradiation baskets and the lower void mechanism with the void out. Burnup and temperature dependent cross-section data were generated using current ANL methods The fuel cycle models include fitted data for the changes in cross-sections with burnup. A cross-section library with 5 energy groups was used for most of the neutronics computations. For the change in reactivity with temperature, where more scattering detail was considered necessary, 10 energy groups were used. The boron loadings for the burnable poison in the sideplates were chosen to reduce the BOL excess reactivity to <8% for each model. This gives the desired shutdown margin of 4 with a control rod worth of 12% assumed for each case. The change in control rod worth with reduced enrichment has not yet determined, but only a small decrease in worth is expected. These BOL boron poisoned fuels are also used as the fresh fuel feed for the equilibrium fuel cycle studies contained in this report. The first three cases shown have matching cycle lengths in the equilibrium cycle, while the last case has a considerably longer cycle length. These results are similarly reflected in the 'Maximum Cycle Lengths' shown for unpoisoned BOL cores. Thus, the first three case can be considered comparable. The last case might be considered as an option for an extended cycle length design. The cycle length for this case is increased by about 21%. Obviously, by decreasing the uranium density in the fuel meat (to 2.7 g/cm{sup 3}), the cycle length for this design could be reduced to match that of the other cases. Thermal-hydraulic calculations have been carried out in order to study the safety aspects of the use of reduced enrichment uranium fuel for the KUHFR. The calculations were based on what is outlined in the Safety Analysis Report for the KUHFR and also the IAEA Guidebook for the RERTR program. Only a few combinations of hydraulic parameters have been tested because the reactor safety cannot be discussed without any nuclear physics considerations. For example, any variations in fuel coolant channels may change not only flow velocities but also power peaking factors which may affect the assessment of reactor safety. For this reason, the thermal-hydraulic calculations were carried out only for those specific cases on which neutronics analysis has been already performed. Low enriched uranium (LEU) cases are also included in this study as initial feasibility studies for potential conversion. The computer code PLTEMP has been developed to calculate the flow distribution in the core, fuel plate temperatures and DNB heat fluxes.}
place = {IAEA}
year = {1983}
month = {Aug}
}