Numerical Simulation of Fission Product Behavior Inside the Reactor Containment Building Using MATLAB

Abstract

The aim of this work is to carry out the numerical simulation of fission product (FP) behavior inside the reactor building under loss of coolant accident (LOCA) using MATLAB. For this purpose, a kinetic model has been developed and implemented in MATLAB to study the behavior of in-containment FPs during postulated LOCA for typical 1000 MW pressurized water reactor (PWR). A continuous release of the FPs from the reactor pressure vessel (RPV) has been implemented with coolant retention. The in-containment FP behavior is influenced by containment atmosphere and contain- ment safety systems. The sensitivity analysis and removal rate of airborne isotopes with the containment spray system have been studied for various spray activation time, spray failure time, droplet size and spray pH value. The droplet size and pH value of the spray system effectively remove the airborne isotopes. The alkaline (sodium thiosulfate, Na 2 S 2 O 3 ) spray solution and spray with pH 9.5 have similar scrubbing properties for iodine. However, the removal rate from the containment spray system has been found an approximately inverse square of droplet diameter (1/d 2 ).