Transient heat transfer in the heterogeneous water reactor, (1)

When a sudden excess reactivity is introduced into a heterogeneous water reactor, the reactor power increases as an exponential function and the fuel element temperature rises rapidly. In many reactors, however, the reactor power does not infinitely increase as an exponential function, but the self-shutdown will be induced by the thermal energy increase in the reactor with increasing the reactor power. Finally, the reactor power stops to increase. As the fundamental problems in the analysis of these reactor kinetics, experimental and theoretical studies were performed on the transient heat transfer between the fuel and the coolant when the reactor power increased exponentially. The methods applying the above mentioned results to the analysis of the reactor kinetics during a power excursion were also shown. The experiments showed a good agreement with the analysis. (author)