不均質,水原子炉における炉内過渡的熱伝達の研究, (I)

Abstract

In the first paper of this serial report, the authors carried out the experimental and the theoretical studies on transient heat transfer in the heterogeneous water reactor when the reactor power increased exponentially, and pointed out that transient heat transfer coefficient can be dealt with approximately as a constant value defined by a reactor period as far as the transient heat transfer is assumed to occur solely by thermal conduction.In the actual reactor power excursion, however, the reactor power does not infinitely increase as an exponential function, and the coolant will start to move along the fuel clad surface before nucleate boiling begins when the rate of the temperature rise of the fuel clad surface is very low. As a consequence of the start of natural convection, the heat transfer becomes better.In this report, by the theoretical analysis of SPERT-I step transient tests, the authors studied on the relation between the transient heat transfer and the reactor power wave forms, and relation between the transient heat transfer and the flow of the coolant during the power excursions of the long reactor periods. In the power excursions of short reactor periods, the transient boiling heat transfer was also studied.