Design, Operation and Maintenance of Thermal Hydraulic Instrumentation System of HTR-10

Abstract

The 10 MW high temperature gas-cooled reactor–test module (HTR-10) reached the first critical at the end of year 2000, and has been running for over 9 years safely and stably till now. Comparing with the Pressure Water Reactor (PWR), HTR-10 has many different characteristics, such as core construction, special fuel elements, helium coolant and so on. Thus the thermal hydraulic parameter measurement has special requirement and it is indispensable to select or develop some new class 1E instrumentation and devices. This paper describes measurement requirements, measurement method and measurement instrumentations for measuring coolant temperature, primary loop pressure, primary loop mass flow rate, primary loop humidity, main steam pressure, feedwater mass flow rate, in-core components temperature, pressure vessel surface temperature. The class 1E sheathed thermocouples and thermocouple penetration assembly, the class 1E orifice plate throttle device, and the data acquisition and supervision system that were developed by the Institute of Nuclear and New Energy Technology (INET) according to the criteria IEEE 323 and IEEE 344 are introduced in detail. HTR-10 has been operated successfully for over 9 years up to the present. The operation and maintenance experience of above-mentioned instrumentations shows they are safe and reliable at normal and abnormal conditions. The experience described in this paper is valuable for the latter 2 × 250 MW modular high temperature gas-cooled reactor.