Thermal-hydraulic conceptual design of the new multipurpose research reactor succeeding to JRR-3

Arai, Masaji ; Tsumura, Takashi

The new multipurpose research reactor is a 30 MW thermal power, swimming pool type research reactor and will be constructed instead of JRR-3 for utilization of the neutron beam, irradiation, training and so on. The core thermal-hydraulic conceptual design of the new multipurpose reactor was performed for the forced convection cooling modes. The key criteria are first to avoid the nucleate boiling anywhere in the core and second to have enough safety margin to departure from nucleate boiling for normal operation conditions. As the results of the thermal-hydraulic analysis, the optimum coolant velocity in the standard fuel element and the core inlet pressure were obtained.