Application of Thermix-Konvek Code to Accident Analyses of Modular Pebble Bed High Temperature Reactors (HTRs).

摘要

The THERMIX-KONVEK code was used to model the steady state and dynamic thermal behavior of the U.S. pebble bed modular HTR concept and trial calculations for accident conditions were performed. Results of these trial calculations are compared with other predictions by ORNL and by industrial proponents. The basic equations, assumptions, and calculational technique employed in THERMIX-KNOVEK are presented. Code validation efforts conducted at Kernforschungsanlage-Julich (KFA) are summarized, and the applicability of the code to the U.S. pebble bed modluar HTR is assessed. It was concluded that the code is applicable to analyses of the safety behavior of the U.S. modular pebble bed HTR. Significant code validation has been conducted using out-of-reactor test loops at KFA. Predicted results agree well with measured data except for test conditions leading to asymmetric behavior which cannot be predicted with the two-dimensional THERMIX-KONVEK model.