Reference Theta-Pinch Reactor (RTPR) nucleonic design sensitivity analysis by perturbation theory

Abstract

Previous system studies for the Reference Theta-Pinch Reactor (RTPR) have included nucleonic calculations for reactions such as tritium breeding, energy deposition, atom displacement, etc. The purpose of the present research was to verify the validity of 25-group cross-section data, along with perturbation theory, to facilitate the above calculations. The effects on these responses due to variations in the Be thickness, choices of Mo, V, or Nb structural material, BeO vs Be, graphite thickness, and /sup 6/Li enrichment were investigated. Increasing the Be thickness from 0.5-5.5 cm increased the tritium breeding from 0.903-1.097 and the neutron heating from 10.29-12.65 MeV per D-T neutron. Gamma emission increased from 7.96-8.76 MeV per D-T neutron. Perturbation theory results for tritium breeding in this study were accurate to within 0.6 percent for the entire range of Be thickness variations. BeO was found not to be a viable neutron multiplier in the present design of the RTPR due to the moderation of neutrons by the oxygen. Perturbation theory was accurate to within 0.3 percent for BeO. Decreases in the outboard graphite thickness up to approximately 7 cm revealed a general slight decrease in tritium breeding, but further decreases to 1.2-cm total thickness resulted in an increase in breeding of approximately 0.6 percent. However, neutron and gamma-ray heating in the coils rises by approximately 300 percent when the graphite region is thinned to 1.2 cm. Perturbation theory is found invalid for graphite thickness changes greater than approximately 1.0 cm. Decrease in /sup 6/Li enrichment from 95-80 at. percent results in a tritium breeding decrease of only 0.6 percent.