MULTIGROUP ENERGY STRUCTURE FOR BA FUEL DEPLETION ANALYSIS
23rd Symposium of AER on VVER Reactor Physics and Reactor Safety (2013, Štrbské Pleso, Slovakia)
Spent fuel storage and disposal
Abstract
Fuel depletion calculation is computationally expensive. Deterministic transport code requires
large amount of computational time that can be cut down by decreasing the number of energy
groups. Current multigroup energy structures with about 200 groups were generated
by merging broader structures and subsequent ad hoc adding of energy boundaries. Recently,
TSUNAMI sensitivity and uncertainty code sequence from SCALE code package was
developed and released. TSUNAMI allows sensitivity calculations that can be used in various
application areas, one of them is energy structure improvement and development.
TSUNAMI code sequence was used to generate sensitivity coefficients describing sensitivity
of multiplication coefficient to neutron energy. Based on sensitivity coefficient values during
depletion, importance of energy groups was defined. Initial 238-group energy structure was
collapsed to new one according to importance data. Fuel depletion calculation with TRITON
code sequence from SCALE code package was executed and multiplication coefficient during
depletion was compared. VVER-1000 fuel assembly with Eu and Er burnable absorbers were
analyzed.