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Successive collision calculation of resonance absorption

Description: The successive collision method for calculating resonance absorption solves numerically the neutron slowing down problem in reactor lattices. A discrete energy mesh is used with cross sections taken from a Monte Carlo library. The major physical approximations used are isotropic scattering in both the laboratory and center-of-mass systems. This procedure is intended for day-to-day analysis calculations and has been incorporated into the current version of MUFT. The calculational model used for … more
Date: July 1, 1980
Creator: Schmidt, E. & Eisenhart, L.D.
Partner: UNT Libraries Government Documents Department
open access

Critical heat flux experiments in a circular tube with heavy water and light water.

Description: Experiments were performed to establish the critical heat flux (CHF) characteristics of heavy water and light water. Testing was performed with the up-flow of heavy and of light water within a 0.3744 inch inside diameter circular tube with 72.3 inches of heated length. Comparisons were made between heavy water and light water critical heat flux levels for the same local equilibrium quality at CHF, operating pressure, and nominal mass velocity. Results showed that heavy water CHF values were, on… more
Date: May 1980
Creator: Williams, C. L. & Beus, S. G.
Partner: UNT Libraries Government Documents Department
open access

Review of thorium-U233 cycle thermal reactor benchmark studies

Description: A survey is made of existing integral experiments for U233 systems and thorium-uranium based fuel systems. The aim is to understand to what extent they give a consistent test of ENDF/B-IV nuclear data. A principal result is that ENDF/B-IV leads to an underprediction of neutron leakage. Results from testing alternate thorium data sets are presented. For one evaluation due to Leonard, the results depict a possible growing discrepancy between measured integral parameters such as rho/sup 02/ and I/… more
Date: March 1, 1980
Creator: Ullo, J.J.; Hardy, J. Jr. & Steen, N.M.
Partner: UNT Libraries Government Documents Department
open access

Fission gas release from oxide fuels at high burnups

Description: The steady state gas release, swelling and densification model previously developed for oxide fuels has been modified to accommodate the slow transients in temperature, temperature gradient, fission rate and pressure that are encountered in normal reactor operation. The gas release predictions made by the model were then compared to gas release data on LMFBR-EBRII fuels obtained by Dutt and Baker and reported by Meyer, Beyer, and Voglewede. Good agreement between the model and the data was foun… more
Date: February 1, 1981
Creator: Dollins, C. C.
Partner: UNT Libraries Government Documents Department
open access

Swelling and gas release in oxide fuels during fast transients

Description: The previously reported swelling and gas release model for oxide fuels has been modified to predict fission gas bahavior during fast temperature transients. Under steady state or slowly varying conditions it has been assumed in the previous model that the pressure caused by the fission gas within the gas bubbles is in equilibrium with the surface tension of the bubbles. During a fast transient, however, net vacancy migration to the bubbles may be insufficient to maintain this equilibrium. In or… more
Date: February 1, 1981
Creator: Dollins, C. C.
Partner: UNT Libraries Government Documents Department
open access

Monte Carlo analysis of Pu-H/sub 2/O and UO/sub 2/-PuO/sub 2/-H/sub 2/O critical assemblies with ENDF/B-IV data

Description: A set of critical experiments, comprising thirteen homogeneous Pu-H/sub 2/O assemblies and twelve UO/sub 2/-PuO/sub 2/ lattices, was analyzed with ENDF/B-IV data and the RCPO1 Monte Carlo program, which modeled the experiments explicitly. Some major data sensitivities were also evaluated. For the Pu-H/sub 2/O assemblies, calculated K/sub eff/ averaged 1.011. The large (2.7%) scatter of K/sub eff/ values for these assemblies was attributed mostly to uncertainties in physical specifications since… more
Date: April 1, 1981
Creator: Hardy, J. Jr. & Ullo, J.J.
Partner: UNT Libraries Government Documents Department
open access

Monte Carlo analyses of simple U233 O/sub 2/-ThO/sub 2/ and U235 O/sub 2/-ThO/sub 2/ lattices with ENDF/B-IV data

Description: A number of water-moderated Th-U235 and Th-U233 lattice integral experiments were analyzed in a consistent manner, with ENDF/B-IV data and detailed Monte Carlo methods. These experiments provide a consistent test of the nuclear data. The ENDF/B-IV data are found to perform reasonably well. Adequate agreement is found with integral measurements of thorium capture. Calculated K/sub eff/ values show a generally coherent pattern which is consistent with K/sub eff/ results obtained for homogeneous a… more
Date: September 1, 1980
Creator: Hardy, J. Jr. & Ullo, J.J.
Partner: UNT Libraries Government Documents Department
open access

Critical heat flux experiments in an internally heated annulus with a non-uniform, alternate high and low axial heat flux distribution

Description: Critical heat flux experiments were performed with an alternate high and low heat flux profile in an internally heated annulus. The heated length was 84 inches (213 cm) with a chopped wave heat flux profile over the last 24 inches (61 cm) having a maximum-to-average heat flux ratio of 1.26. Three test sections were employed: one with an axially uniform heat flux profile as a base case and two with 60 inch (152 cm) uniform and 24 inch (61 cm) alternating high and low heat flux sections. The thir… more
Date: February 1981
Creator: Beus, S. G. & Seebold, O. P.
Partner: UNT Libraries Government Documents Department
open access

Thermomechanical theory of materials undergoing large elastic and viscoplastic deformation

Description: A thermomechanical theory of large deformation elastic-inelastic material behavior is developed which is based on a multiplicative decomposition of the strain. Very general assumptions are made for the elastic and inelastic constitutive relations and effects such as thermally-activated creep, fast-neutron-flux-induced creep and growth, annealing, and strain recovery are compatible with the theory. Reduced forms of the constitutive equations are derived by use of the second law of thermodynamics… more
Date: November 1, 1980
Creator: Martin, S.E. & Newman, J.B.
Partner: UNT Libraries Government Documents Department
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