Computational analysis of a blackout accident at a decomissioned RBMK.

In order to improve the safety of operating nuclear power plants with RBMK-1000 reactors, work is underway for developing and substantiating the control actions of personnel under severe accident conditions for all possible initial states of the power unit, including shutdown for decommissioning. An accident is considered using the STEPAN‑T 3D program developed specifically for simulating an accident with the complete blackout of a RBMK reactor. The time dependence of the temperature in the core, metal structures, and OR scheme is given. Quantitative estimates of the hydrogen formation during an accident are shown. The possibility of re-criticality and release of radioactive substances occurring during the accident are discussed. Possible measures to mitigate the consequences of the accident are given. [ABSTRACT FROM AUTHOR]