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Conference Article: Safety Demonstration Tests On HTR-10

Abstract

The 10MW High Temperature Gas-cooled reactor (HTR-10) is a graphite-moderated helium gas-cooled reactor with the thermal power of 10MW and the reactor outlet temperature of 700 ?. Safety demonstration tests on the 10MW High Temperature Gas-cooled Reactor (HTR-10) were conducted to demonstrate the inherent safety features of HTR-10 as well as to obtain the core and primary cooling system transient data for validation of safety analysis codes. Two simulated anticipated transients without scram (ATWS) tests, lose of heat sink by tripping the helium blower without scram and reactivity abnormal increase by means of withdraw a control rod without scram were selected as first phase safety demonstration experimental items. This paper describes the tests with detail experimental method, experimental condition, measures for guaranteed safety and experimental results. The test of tripping the helium circulator ATWS was conducted on October 15,2003. Helium blower was switched off during normal operation with 3MW, that means primary coolant system was disconnected. Although none of 10 control rods was moved, the reactor power immediately decreased due to the negative temperature coefficient. After 50 minutes, the reactor becomes criticality again. The output power went to a stable level with about 200kw. The test of reactivity increase ATWS was carried out two times. The quantity of reactivity increased were 1×10-3?k/k and 5×10-3?k/k by a control rod withdrew 12cm and 130cm with moving speed 1cm/s respectively during reactor normal operation with 3MW. Following the control rod withdrew, the reactor power increased, the maximum power level reached to 5037kW and 7230kW corresponding reactivity of 1×10-3?k/k and 5×10-3?k/k. Then, the engineering safety features executed safety actions, helium circulator stopped, primary and secondary circuits insolated. The reactor power decreased sharply by means of negative reactivity feedback due to the increased of core temperature, and reached to a stable level about 200kW after 2 hours later. The main parameters such as helium pressure, graphite structure’s temperature, metallic support’s temperature and pressure vessel’s temperature is far below the safety limitation during both tests conducted.

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Reference:

Proceedings of the Conference on High Temperature Reactors, Beijing, China, September, 22-24, 2004

International Atomic Energy Agency, Vienna (Austria)

HTR-2004, pp:1-16