PRTHRUST and PRTHRUST-J1: computer codes for calculating blowdown thrust force

This paper describes the outlines of PRTHRUST code and PRTHRUST-J1 code which is a modification of the former one. This paper also presents some numerical examples in order to show the effectiveness of PRTHRUST-J1 code. PRTHRUST code can calculate transient blowdown thrust force and jet impingement force resulting from a postulated pipe rupture. This code, however, has the following limitations; (1) The region from break point to first elbow must be modeled by one control volume. (2) Only the blowdown thrust force at the first elbow can be obtained. Then, PRTHRUST code was so modified as to model the system more precisely and analyze the pipe rupture test performed in JAERI. This modified code is named PRTHRUST-J1. The two problems of the saturated steam blowdown and the jet test performed in JAERI were solved by PRTHRUST-J1 code. The results of the former analysis were compared with those of the simplified method by Moody. In the latter analysis, it was examined how the difference of modeling the system influenced on the results. (author)