Experimental and Analytical Study on Chemical Reaction Loss Accident With a Mock-Up Model of HTTR Hydrogen Production System

Japan Atomic Energy Research Institute has been developing a hydrogen production system coupling with the High Temperature Engineering Test Reactor (HTTR). In the design of a HTTR hydrogen production system, a steam generator (SG) is installed at the downstream of a chemical reactor, a steam reformer (SR), as a thermal absorber to keep the secondary helium gas temperature within an allowable value at an intermediate heat exchanger inlet to prevent a reactor scram. Prior to construction of it, a mock-up model test facility, approximately 1/30-scale model of the HTTR hydrogen production system, was fabricated and simulation test on chemical reaction loss accident has been carried out to investigate the mitigation of thermal disturbance using SG. It was confirmed that fluctuation of helium gas temperature could be mitigated within a target range from −10 to 10°C at SG outlet, whereas SG inlet helium gas temperature increased 231 °C, and numerical analysis results agree well with experimental results.