Comprehensive Safety Analysis Code System For Nuclear Fusion Reactors I: Model And Analyses of Overpower Events for the International Thermonuclear Experimental Reactor

Abstract

A comprehensive safety analysis code system has been proposed for the quantitative investigation of the safety of nuclear fusion reactors such as the International Thermonuclear Experimental Reactor (ITER). As a first step, the plasma dynamics and the thermal characteristics of the core internal structures have been developed by a one-point model and a time-dependent one-dimensional heat transfer model, respectively. The thermal behavior of ITER during overpower events caused by thermal instability of the plasma has been analyzed. In a truly ignited operation (Q [approximately] [infinity]), the plasma reaches the beta limit in [approximately]6.5 (3.5) s after insertion of a + 10% fluctuation in fuel density, when the ITER89-L power law (the offset-linear law) is applied. The surface temperature of the divertor tiles rises to [approximately]1900[degrees]C, which may result in damage from erosion and thermal stress. On the other hand, the outboard and inboard structures maintain their integrity during overpower events if the cooling systems function normally. The code system will be integrated step by step to provide overall safety analyses for nuclear fusion reactions. 37 refs., 13 figs., 1 tab.