Nucleonic analysis of the ETF neutral-beam-injector-duct and vacuum-pumping-duct shields

TLDR: In this article, a hybrid Monte Carlo/discrete-ordinates method was used to determine internal and external boundary surface sources for subsequent discreteordinates calculations of the neutron and gamma-ray transport through the shields.

Abstract: A nucleonic analysis of the Engineering Test Facility neutral-beam-injector-duct and vacuum-pumping-duct shields has been made using a hybrid Monte Carlo/discrete-ordinates method. This method used Monte Carlo to determine internal and external boundary surface sources for subsequent discrete-ordinates calculations of the neutron and gamma-ray transport through the shields. Confidence was provided in both the hybrid method and the results obtained through a comparison with three-dimensional Monte Carlo results. Also determined in the analysis were the energy and angular distributions of neutrons and gamma rays entering the neutral-beam-injector duct from the toroidal plasma chamber, as well as exiting the duct into the neutral-beam-injector chamber. In addition, the energy and angular distributions of neutrons entering the vacuum-pumping chamber were determined.