Nuclear Technology / Volume 177 / Number 2 / February 2012 / Pages 157-175
Technical Paper / Fission Reactors
This paper introduces a combined micro and macro (CMM) parameter perturbation theory for boiling water reactor (BWR) lattice design and optimization, which involves a large number of independent design variables and a large scale of variations. With this theory, engineers are able to meet the challenges from both accuracy and speed requirements. This theory was applied to the BWR fuel assembly lattice design in AREVA. A BWR fast lattice simulator (FLS) and a BWR fuel assembly lattice optimizer (BALO) were built and assisted engineers working on the lattice design and optimization. In addition to the discussion of this theory, the BALO/FLS calculation results are used to show that this theory can meet both speed and accuracy criteria of design as well as cover the large design range. Moreover, the results also show that two major perturbation issues in BWR lattice design and optimization, i.e., the large swing of average lattice enrichment and the thermal neutron black absorber's distribution as burnable poison can be resolved with the CMM perturbation theory. Finally, it is pointed out that the macro parameter perturbation combined with the micro parameter perturbation is extremely important to the accuracy.