Distributed Parameter Control Method for Axial Neutron Flux in Fast Nuclear Reactor

If the axial neutron flux distribution could not be controlled, the power at some locations in the nuclear reactor core might exceed the thermal limits, resulting in increased chances of fuel failure. In fact, the power is proportional to the neutron flux, it is necessary to develop a neutron flux distribution control method. However, the nuclear reactor is a kind of distributed parameter system (DPS) which brings a great challenge for the traditional lumped parameter control method. In this paper, we mainly focus on the fast reactor that present a distributed parameter control (DPC) method framework such that the closed-loop neutron flux distribution control system is exponentially stable. Initially, the closed-loop exponentially stable sufficient conditions of the control law for the neutron flux DPC problems are provided based on the integral Lyapunov function. The most important characteristic of the control law is that the absorption cross section needs to be changed globally and simultaneously in the axial direction. The analysis shows that the control law can be realized by the rotating drum theoretically because it can strictly conform to the reactivity insertion constraint of the control law. The spatial differential linear matrix inequality optimization techniques are employed to approximately solve the suboptimal integral control law design problem. The numerical experiment of the Lead-Bismuth Eutectic-cooled fast reactor shows that the initial neutron flux peaks could be inhibited by this distributed control method effectively and rapidly.