PHYSOR 2016
Noting that the B1 leakage correction method that has been used conventionally in the assembly homogenized group constant (GC) generation procedure cannot properly reflect the actual leakage in the core due to the energy dependency of leakage, a new leakage feedback correction method for determining assembly homogenized GCs in the core calculation is developed and validated by employing a leakage fraction (LF) based functionalization scheme. The analysis of a large number of CB configurations shows that the effective GCs are almost linearly proportional to the group LFs. This observation leads to a scheme where assembly GCs generated from several sets of CB calculations are functionalized with respect to leakage fractions. The functionalized GC library is then used in a core calculation scheme where the GCs are iteratively updated using the group LFs obtained from the core calculation. A special leakage treatment is introduced to the peripheral assemblies facing the reflector to properly consider the significantly larger leakage effect. Validation is performed with two-dimensional core problems of the BEAVRS and the VERA benchmarks. It is verified that the new leakage feedback correction method can properly correct the leakage effect on GCs and produce better solutions.
