Effectiveness analysis of the reactor operator’s adviser computer code

Abstract

Testing of the computer code Reactor Operator's Adviser on the No. 3 unit of the Leningradskaya nuclear power plant showed that the recommendations given in the code increase substantially (by a factor of 1.2) the minimum margin to the P2 level for the adjusted signal from the in-reactor detectors along the radius and decrease the maximum temperature of the graphite masonry by 12°C and the maximum nonuniformity factor of the energy release distribution by 3%. Operation for 3.5 h using the Reactor Operator's Adviser code recommendations maintained the operational parameters characterizing the energy release distribution along the core radius and height within acceptable limits.The quality of the smoothing of the energy-release distribution over the volume (radius and height) of the core increases the operational safety of nuclear power plants with RBMK-1000. For this purpose, a cybernetic model of the reactor operation has been developed [1] and implemented in the computer code Reactor Operator's Advisor (SOPR) [2], which is intended for automatic optimization of the distributed parameters of the core in RBMK-1000 reactors equipped with the Skala-Micro information-measurement system. The code is also supposed to be incorporated in the complex monitoring, control, and protection system for automatic optimization of the volume distribution of the energy-release.The procedure for smoothing the energy-release distribution in RBMK-1000 is an optimization problem where the goal function with possible power increase is minimization of the coefficient K v of volume nonuniformity of the energy release or the lineal power density of fuel elements in the plateau zone with a limit on the reactor power. The latter makes it possible to decrease the neutron leakage and increase the depth of fuel burnup [3]. In both cases, the final goal function is to increase the cost-effectiveness of nuclear power plants with RBMK-1000 reactors with all safety requirements being met. In the course of optimizing the energy-release distribution, the operator or the SOPR code must take account of the effectiveness criteria: increasing the margin to the maximum admissible power of the technological channel, maintaining an operational margin for the control rods used for local automatic control in a prescribed range, not decreasing below the maximum admissible margin with respect to critical heat transfer for the lineal density of the power and masonry graphite temperature, not permitting close approach to the emergency setting of the signals from in-reactor detectors along the radius, and others. Because of the difficulty of minimizing the energy-release coefficient K v a spectrum of effectiveness criteria is used in practice and in the development of metrics. Such an approach, called simulation modeling [4], for RBMK-1000 has been implemented in the SOPR code.Operational optimization of the energy-release distribution has gone through several developmental stages. Initially, the plan was to use the method of linear programming with a matrix model...