A man-machine communication system has been developed for boiling water reactor (BWR) core management planning to provide a very flexible tool, which is complementary to automated optimization programs that maximize or minimize one particular performance index under certain constraints. A three-dimensional BWR simulator, which can cover a wide range of BWR operating conditions, has been developed and coupled with a graphic display serving as a main input-output controlling device. The system has been successfully applied to generate a long-term control rod programming of a BWR in which locally poisoned fuel assemblies are loaded. The time required for one cycle analysis is ∼3 h, out of which the actual computation time is only 4 min with an average of three trials of rod pattern search per exposure step. The quick response (∼5 sec) and the visualized results on the screen are very helpful in understanding the complicated characteristics of the BWR core, and it is found that this kind of tool has a very great educational effect. A similar approach is expected to be applied in other fields suck as core design and safety analysis, as well as in core management.