Development of versatile nuclear heating calculation system in MARBLE

Hazama, Taira ; Yokoyama, Kenji   

A versatile nuclear heating calculation system is developed in MARBLE, a neutronics calculation platform based on the object-oriented language. The system provides a variety of heating calculation methods from the conventional simple methods based on energy-independent Q-values, to a detailed method based on NJOY. A particular feature is in hybrid methods that consider energy dependence employed in NJOY in the system. The hybrid methods provide tools to assess errors in the simple methods and to evaluate the heat transport property by neutrons and photons precisely. The accuracy of the hybrid methods and the errors in the simple methods are investigated in a Monju design calculation. It is confirmed that the hybrid methods realize the nuclear heating by the detailed method within an accuracy of 0.1%. The neglect of incident energy dependence of the fission Q-value in the simple methods causes clear overestimation in the Q-value but its influence on the total heating is less than 1%.