Optimization of in-core fuel management, cycle period and power scheduling of nuclear power plants by large scale nonlinear programming

In the light of the strong interaction between in-core fuel management and cycle-power scheduling, the optimization should be carried out over the wider planning horizon of the overall utility system management, before sticking to the details of reactor physics. The report aims at the minimization of the power cost of the utility system, which consists of nuclear power plant(s) and one backup fossil power plant. The decision variables are batch size of the non-equilibrium refueling pattern, cycle power, derating and cycle length. The optimization is subject to several constraints in reactor operation and power system scheduling. The problem characterized by the large scale nonlinear programming, is decomposed in two stages: Suboptimization of nuclear unit by Linear Programming and overall coordinative optimization for system power cost with the use of gradient projection method. A typical example on BWR is studied. In most cases of normal operation, the economical solution is obtained by filling up the margins involved in design parameters and operational constraints. The economic incentive is especially enhanced in the planning of recovery transient after unexpected plant outages or any disturbance to the precalculated operational scheme. (12 references) (U.S.)