Analysis of SHE critical experiments by neutronic design codes for experimental very high temperature reactor.

Abstract

Analyses have been performed on various experiments conducted using the Semi-Homogeneous Experimental Assembly (SHE) to examine the accuracy of computer codes employed in the neutronic design of experimental Very High Temperature Reactor (VHTR). The neutronic design codes are DELIGHT-6 to obtain the neutron spectrum of a fuel cell and to produce group constants with burnup utilizing the nuclear data from ENDF-B/IV, CITDEGA to calculate the three-dimensional core performance considering the coupling effect between neutronic and thermohydraulic characteristics, and ANISN-JR and TWOTRAN-II for transport calculation. These codes are examined by the analysis on the integral quantities of effective multiplication factor, neutron flux distribution, burnable poison rod worth and control rod worth. The maximum degrees of disagreement with the relevant experiments are 0.57, 5, 7 and 5%, respectively.