Analysis Of Criticality Experiments Of Bandung Triga 2000 Reactor By Using MCNP-4B Code

During the first core loading of Bandung TRIGA 2000 reactor, two kinds of criticality experiment have been conducted, i.e, sub critical core loading and critical core loading experiments. The purpose of the experiments is to maximize the utilization of the reactor as well as to provide benchmark data for neutronic computer codes. In the sub critical core loading experiment, the core is loaded up to 42 fuel elements ring D, 13 fuel elements in ring, D, 6 fuel elements and 3 graphite dummies in ring E, 2 fuel elements in ring B, 2 fuel elements in ring B, 1 fuel element in ring B. In the other case, during the critical loading experiment, the core is loaded following the loading pattern planned by General Atomics, i.e: 20 fuel elements in ring B, C and D plus 5 control rods in ring D, 11 fuel elements in ring D, 6 fuel elements and 3 graphite dummies in ring E, and then the core is loaded with additional fuel elements, step by step, until the core reached its first criticality, i.e., 55 fuel elements. Prior to conduct of criticality experiments MCNP-4B code is used to plan the fuel loading pattern of the sub critical loading experiment, i.e. to assure that the core is still in sub critical state with 42 fuel elements in the core. In the calculation is assumed that the mass of U-235 in each fuel element depends on the documented burnup data, the mass of U-238 is assumed to be the same as the one in fresh fuels. Furthermore, all fission patricides as well as poisonous materials in each fuel element are ignored. The experiment results showed that the calculations of MCNP-4B also predicted that TRIGA 2000 reactor with the above assumptions, is appropriate for predicting for predicting the neutronic characteristics of Bandung TRIGA 2000 reactor