Institute for Neutron Physics and Reactor Technology (INR)


We develop and apply COUPLE, a neutronics and thermal-hydraulics coupled code, for transient analyses of molten salt reactors. Recently, we extended the code for two-phase simulations and implemented a channel model for code application to reactors with solid fuel.



(a) Velocity                         (b) Pressure

Fig. 1. COUPLE calculated velocity and pressure distributions in MSFR (Molten Salt Fast Reactor)


Fig. 2. COUPLE visual snapshots of water mass distribution (color bar: volume fraction of water phase): simulation of a dam break experiment for code validation



  1. Zhang D., Zhai Z.-G., Chen X.-N., Wang S., Rineiski A., COUPLE, a coupled neutronics and thermal-hydraulics code for transient analyses of molten salt reactors, Transactions of the American Nuclear Society, 108, pp. 921-922.
  2. Guo L., Chen X-N., Rineiski A., further development of COUPLE code taking account of gas-liquid interfacial motion, 11th Int. Topical Meeting on Nuclear Reactor Thermal Hydraulics, Operation and Safety (NUTHOS-11), Gyeongju, Korea, October 9-13, 2016.