DEVELOPMENT OF DECAY HEAT MODEL FOR RAST-K

Decay heat (DH) is the produced through a radioactive decay of fission products during or after reactor operation. It known as second largest source power in core fission. Being such strong contributor to power, it should be accurately determined at any time Currently, there are two main approaches for DH estimation used simulation codes. One approach based on careful inventorying all target nuclides and their individual contributions total power. Alternatively, other popular collapsing into small number groups similar delayed neutron techniques. However, last (multigroup) method currently has limitations when some transient scenarios transients occurred fresh fuel. In this study, multigroup was further developed reducing while retaining advantage computation speed. Then, implemented Reactor Analysis code Steady state Transient (RAST-K) tested against As result, improved found capable determining stages operation under scenario. particular, test simulations using showed better results those that were accuracy original method. Overall, quality calculations RAST-K newly module.