The Sandwich Method for Determining Source Convergence in Monte Carlo Calculation

Development of a Method to Calculate keffSatisfying a Convergence Criterion of Source Iteration in Monte Carlo Calculation

“…Therefore, the influence of the initial source distribution should be observed, but this is not considered in the method to obtain the ''stopping criteria'' reported by Shim and Kim. 2) The influence of the change of FSDs in each source iteration is generally considered in source iteration calculations; however, the initial source distribution affects FSDs the most. We would like to stress the importance of evaluating this influence.…”

Review of studies on criticality safety evaluation and criticality experiment methods

“…As a method for avoiding false convergence, Naito and Yang proposed the novel "sandwich method" [28]. The essence of the sandwich method is that a true converged k eff can be found between two k eff that are obtained from two extreme initial source guesses giving the highest and lowest k eff , respectively.…”

A Mesh-Input-Free On-The-Fly Source Convergence Indicator in Monte Carlo Power Method

“…The first problem is the fresh fuel vault of a pressurized water reactor 18) described as follows. The fuel bundles are placed in water-filled 24-by-3 lattices in a checkerboard manner; the whole lattices are surrounded by water and concrete; neutrons are overmoderated and the source distribution has a sharp peak at the only fuel bundle facing concrete on two sides; 4) all other fuel bundles face concrete on one side at most. The dominance ratio was computed to be 0:9943 AE 0:0008 in one standard deviation by the autoregressive moving average (ARMA) fitting.…”

“…Therefore, an on-the-fly judgment of the entrance to an equilibrium fluctuation range of the true source distribution has been under intensive investigation. Naito and Yang 4) studied the idea of a sandwich method by the two-neutron multiplication eigenvalues resulting from two different source distributions. However, the sandwich method has not been tested for the slowly varying source distribution over a large domain as those of three-dimensional reactor cores.…”