Deterministic Safety Technology for RBMK Reactors

The present paper deals with the description of the technical activities conducted within the TACIS Project R2.03/97, EC Contract No 30303, related to RBMK. The Project activities are focused toward the setting-up of a chain of computational tools suitable for the analysis of transients expected in the RBMK NPP. The accident leading to the rupture of one pressure channel with fuel melting or high temperature damage, creep and brittle failure of the pressure tube and of graphite bricks with possibility of rupture propagation, constitutes the reference scenario for the Project. However, a series of expected scenarios has been selected to prove the capability of the individual codes or chains of code in simulating the envisaged phenomenology. The result of 30 man-years effort is summarized hereafter including activities performed at NIKIET in Moscow and at UNIPI in Pisa. A top-down approach is pursued in structuring the Executive Summary that includes the following sections: - The safety needs for the RBMK NPP are described first: this includes the overview from the starting tasks and the key findings from the execution of the Project. - The road-map is discussed that gives an idea of the interdisciplinary nature of the Project and of the related complexity. - The adopted computational tools are presented in the third paragraph including codes and input decks or nodalisation. In this section, the transient scenarios established for proving the validity of the code and code chains are discussed. - Key findings are presented per each logical block of activities planned within the road-map. - Emphasis is given to the MPTR issue and the ICM proposal.