Key design parameter study (III) for large scale-up fast breeder reactor; Parametric calculations for evaluation of sodium leak accident

Hiroi, Hiroshi*; Matsuki, Takuo*; Miyake, Osamu; not registered; Himeno, Yoshiaki

Following the study in JFY86, parametric calculations of a sodium leak accident in the plant were conducted using the CONTAIN code. This is to clarify influences of the design conditions and assumptions of the accident and to study characteristics of the "hot cell" concept and the "confinement united with the building" system. In addition, a model of heat transfer from bare pipes and components was incorporated into the code. The major conclusions are as follows: (1)Incorporation of the model of heat transfer from bare pipes to the cell atmosphere reduced the release of fission products (FP) to 2030% of that obtained in the previous calculations in JFY86. (2)The most influential parameter on the FP release was the leak rates of cell to the confinement or the atmosphere. (3)Location of sodium leak, oxygen concentration in the cell, and capacity of the normal off-gas system scarcely affected the FP release. (4)The FP release in all calculational cases were far below the target values which are assumed for a site evaluation of a large FBR.