Newly-designed capsules for fuel ramp tests in the JMTR

Hanawa, Satoshi ; Ogiyanagi, Jin ; Inaba, Yoshitomo  ; Sasajima, Hideo ; Nakamura, Jinichi ; Nakamura, Takehiko 

In order to perform power transient tests of new design LWR's fuels, new power transient test capsules, the natural convection capsule and the forced convection capsule, are being developed. The natural convection capsule has relatively simple structure, and the test fuel rod is cooled by the natural convection of the coolant. The basic technologies for the natural convection capsule have already been established and the power transient tests will be started by using this capsule. The forced convection capsule has relatively complicated structure for circulating the cooling water and controlling the cooling water temperature. By performing several mock-up test, we confirmed that the target linear heat rate is achievable by the capsules, and elemental technologies to realize the forced convection capsule is feasible.