Ways of altering the coefficients of reactivity in RBMK reactors

Abstract

In RBMK reactors there are many possibilities of acting on the coefficients of reactivity, primarily on the steam-void coefficientα ϕ . Some of these methods can be implemented only by building new reactors and are irreversible (e.g., changing the lattice pitch of the fuel assemblies). Other ways of great interest make it possible to operatively act on the coefficients of reactivity even in existing reactors. These include such strong, but economically acceptable, measures as keeping some auxiliary absorbers in the reactor core or increasing the operational reactivity margin as well as economically effective measures involving an increase in the density of the fuel and in the initial enrichment. An extremely great effect on the steam-void coefficient of reactivity is displayed by such operating modes as maintaining the mean water density in the reactor and the energy distribution over the height at a required level.