Effect of Moderator–Coolant Chemical Interaction on Accident Development in the No. 4 Unit of the Chernobyl NPP

Abstract

The accident in the No. 4 unit of the Chernobyl NPP destroyed the reactor and enclosures and resulted in atmospheric emissions of fission products, irradiated fuel, moderator, and other radioactive materials. The large-scale destruction could have been due to the chemical interaction of the coolant (water) and moderator (graphite) with carbon monoxide and hydrogen forming at temperatures above 1000 K. The results of calculations of the composition of a thermodynamically equilibrium mixture in the system of elements C–H–O and measurements of the characteristic graphite-water interaction time at ~1500 K are presented and this time is compared with the characteristic development time of the accident at the Chernobyl NPP.