Xenon oscillation prediction method and computer program for xenon oscillation prediction

摘要

To predict xenon oscillation at the present time and later. For this purpose, as an axial offset of a power distribution of a reactor is represented by AOp, an axial offset of a power distribution based on xenon distribution is represented by AOx, and an axial offset of a power distribution based on an iodine distribution is represented by AOi, a parameter DAOpx(=AOp−AOx) and a parameter DAOix(=AOi−AOx) are described by a relational expression of a trigonometric function and an exponential function using an angular frequency of xenon oscillation. Next, phases with respect to initial values of the parameters DAOpx and DAOix are obtained (Step S101). The parameter DAOpx and the parameter DAOix expressed by the obtained phase and a coefficient of the relational expression obtained from this phase are plotted on an X coordinate and a Y coordinate, respectively. A locus at the present time and later is predicted using the locus obtained in this manner (Step S102), and a timing of extinguishing the xenon oscillation is predicted (Step S103).

主权项

1. A xenon oscillation prediction method comprising:
describing, by relational expressions between a trigonometric function and an exponential function using an angular frequency of xenon oscillation, a parameter DAOpx(=AOp−AOx) and a parameter DAOix(=AOi−AOx), in which AOp is an axial offset of a power distribution of a reactor, AOx is an axial offset of a power distribution casued by xenon distribution, and AOi is an axial offset of a power distribution caused by iodine distribution, as
DAOpx=X(t)=a×cos(ω×t−φp)×exp[λ×t] andDAOix=Y(t)=b×sin(ω×t)×exp[λ×t], where coefficients ω, φρ, a, b and λ are determined from parameters expressing nuclear characteristics of the reactor or from operation data; obtaining a phase with respect to initial values of the parameter DAOpx and the parameter DAOix; obtaining the coefficients of the relational expressions with respect to the initial values of the parameter DAOpx and the parameter DAOix; and predicting a state of xenon oscillation after the initial values, information of a locus obtained by plotting the parameter DAOpx and the parameter DAOix expressed, respectively on an X coordinate and a Y coordinate, by the relational expressions described by the obtained phase and coefficients.