Study on MOX Core Characteristics of Experimental Power Reactor using MCNP6 Code

In experimental power reactor (reaktor daya eksperimental, RDE), a full MOX fueled core can be accommodated in its operation without significant modifications on the reactor core design, but the MOX core tends to produce less favorable safety features and deliver transient behavior into unwanted fatal accidents. This paper aimed to investigate the MOX core characteristics of RDE through a series of calculations with MCNP6 code and ENDF/B-VII library. The calculation results show that MOX core with 235U enrichment of above 5 % can reach the criticality condition, maintain and run the reactor during the operation cycle. Utilizing MOX fuel in RDE with lower 235U enrichment will have a more negative impact on temperature coefficient of reactivity. The lower β eff makes the MOX core is more difficult to control, especially with low 235U enrichment. These results conclude that the selection of 235U enrichment in the MOX core must be carefully considered because it is one of the strategies to ensure the reactor safety criteria are fulfilled.