Development of the engineered pressure maintenance system, (1)

This paper describes the results and evaluation of the first-stage experiment and its analysis (by LOOP78 code) for the scaled Engineered Pressure Maintenance System (EPMS). The EPMS is effective as a protection system for the intermediate heat exchanger (IHX) of the experimental multipurpose very high-temperature gas-cooled reactor (VHTR) planned by the Japan Atomic Energy Research Institute (JAERI). The IHX of VHTR is designed for differential pressure between the primary side (containing radioactive gas) and the secondary side due to its high temperature such as 10000C. The IHX is an important barrier for public safety concerning radioactivity when a hypothetic depressurization accident in the secondary side occurs. The EPMS as a protection system for IHX consists of high pressure tanks, rupture discs, isolation valves, flow restrictor and data acquisition and processing (DAP) system. By the experiment and analysis, the following items have been verified: 1. The analytical method is reasonable in experimental condition. 2. The DAP system including the quick-response pressure gauges and isolation valve performed their functions satisfactorily. Several improvements are presented at the end of the paper. (author)