Performance test of conceptually designed hydraulically suspended passive shut down subassembly for CFR600

Highlights: • The performance of the HS-PSS prototype of CFR600 was experimentally investigated on the VERCH test facility in water. • The critical flow rate of HMB suspension in the upper working position at 84 °C is 1.8 kg/s. • The drop time of HMB under the coast-down flow at 84 °C is 10.65s, which meets the design requirements. • Experimental validation qualifies the calculation program developed. Hydraulically Suspended Passive Shutdown Subassembly (HS-PSS) of Sodium-cooled Fast Reactor (SFR), which can protect the reactor from beyond design basis accidents, is especially suitable for responding to the Unprotected Loss of Flow accident (ULOF). In this study, the performance of the conceptually designed HS-PSS for China Fast Reactor with 600 MW electric power (CFR600) that is being developed by the China Institute of Atomic Energy (CIAE) was experimentally investigated. Suspension tests, free drop performance tests, and hydraulic characteristic verification of the HS-PSS were carried out on a specially constructed vertical hydraulic test loop. Furthermore, the hydraulic characteristic data such as suspension critical flow rate, drop time, pressure drop, and hydraulic thrust on the Hydraulically Moving Body (HMB) inside the HS-PSS was obtained to verify whether they meet the design requirements. The HMB prototype has a drop time of 10.65s under the coast-down flow rate, and the initial falling critical flow rate is 1.80 kg/s, at 84 °C. Both agree well with the theoretical calculation results and meet the engineering design requirements.