Optimizing rod movements method to realize 3-D power distribution control for load follow

The load-following problem in nuclear reactor is traditionally solved by 1-D neutron flux model. It is not always appropriate, especially when control rods, which are strong neutron absorption bodies, maintain the power changing procedure by itself. A 3-D neutron flux model is used to perform a 3-D power distribution control over the whole load-following procedure. To make it effective and improve the calculating performance, the Harmonic synthesis method and Nodal method are combined in the load-following calculation for optimization. For this purpose, the control rods are managed according to the grouping-control strategy. From the calculation results on the 200 MW Heating Reactor, it can be seen that this rod-managing-strategy produces a better control result than other strategies, since it makes full use of the advantages of the 3-D power distribution control. For example, it causes the power peaking-factor to lessen about 4%.