Calculating the startup-sensor readings of the control and safety system of a BN-600 reactor on the basis of simultaneous solution of the direct and conjugate neutron-transfer equations

Abstract

This paper attempts to improve the quality of calculation of additional sets of startup equipment (ASSE) sensor readings using a trend that has developed in perturbation theory. Calculations taking account of modeling of startup sensors of the BN-600 reactor on the BFS-2 test stand gave underestimates of the sensor reading by a factor of approximately 3-4 in comparison with measurements obtained in startup. The general idea is the same as in the theoretical-experimental approach, i.e., to split the complex initial problem into two simpler problems: calculation of the reactor without a detector unit (unperturbed problem) and calculation of the detector unit, regarded as a perturbation, separately from the reactor. The method presented has been used to calculate such functionals as the activation of the second-loop sodium in the design of a fast reactor at Clinch River, the dose from neutron radiation in the building above the lid of the FFTF reactor, the dose from gamma-radiation of a commercial fuel-processing plant, etc. The method used to calculate the start-up sensor readings of the control and safety system of a BN-600 reactor allows the calculation scheme to be brought into closer agreement with the initial physical model than in the traditional approachmore » and allows the resources of the DD and SMK-10 calculation programs to become more optimally distributed.« less