Mercury target thermal hydraulic design for JAERI spallation neutron source

Kaminaga, Masanori  ; Haga, Katsuhiro  ; Kinoshita, Hidetaka   ; Terada, Atsuhiko*  ; Koikegami, Hajime*; Hino, Ryutaro

1MW pulsed spallation neutron source using a mercury target will be constructed in order to produce high-intensity neutrons for use in the fields of life and material sciences. The mercury target is proposed using a high-energy (3.0GeV) proton beam with a current of 0.333mA and operating at 25 Hz with a pulse duration less than 1s. A cross flow type (CFT) mercury target has been designed in order to distribute mercury flow according to an axial heat generation distribution caused by spallation reaction, based on the thermal hydraulic analytical results of 3GeV, 1MW proton beam injection by using the STAR-CD code. This paper presents the final CFD analytical results. In the analysis, an inlet temperature of 50C and an inlet mercury velocity of 1.0m/s were assumed. As results, a maximum velocity of 2.48m/s was observed near the front end of the outlet plenum and a maximum of 125.5C was observed near the beam window where the volumetric heat generation rate was relatively large. The maximum temperature is far below the mercury saturation temperature of 356C under atmospheric pressure. This result satisfied the thermal-hydraulic design criteria of "Maximum mercury temperature in the target shall be less than 300C".