Experimental analysis of step reactivity insertion effect on reactor power, fuel temperature and reactor period in BAEC TRIGA research reactor

•Reactor power and fuel temperature are investigated due to positive and negative step reactivity insertion.•Significant variations in the reactor power and reactor period are found due to the effect of low initial power.•The reactor period is calculated and a comparison is shown how the initial power affects the reactor period. A series of experiments has been performed in a 3 MW BAEC TRIGA Mark-II Research Reactor to analyze the effects of positive and negative step reactivity insertion. The responses of reactor power and fuel temperature were determined. The reactor period is also calculated and a comparison is shown how the initial power affects the reactor period. This research illustrates the behavior of the delayed neutron in response to step reactivity insertion. After sudden step reactivity insertion (positive or negative), a sharp change in reactor power and fuel temperature has occurred initially, then the variation slows down followed by stable reactor period. In spite of inserting same positive and negative step reactivity, the amount of subsequent increase and decrease in reactor power and fuel temperature were not same. Significant variations in the reactor power and reactor period are found due to the effect of low initial power.