Non-Empirical Analysis of the Chemical Reaction of Cesium with Steam; CS+H₂O→CsOH+H, in Severe Light Water Reactor Accidents

Abstract

The elementary chemical reaction of cesium which is a volatile fission product with steam (water) shown in the title are analyzed from the first principle. The activation energies for both reactions of the forward and the backward are calculated for the first time with a computer program Gamess, which is based on the non-empirical molecular orbital theory. The calculated values are expected to agree with those of experiments within an accuracy of several tens of kJ/mol. Using the values obtained above, the rate constants are also calculated in the framework of the transition state theory. The derived rate constants will allow us to predict the orders of magnitude of experimental values under high temperature conditions (1,000K or higher). Thus these rate constants are available as input data for the kinetic (non-equilibrium state) study of cesium in severe light water reactor accidents.

KEYWORDS:

• severe accident
• fission products
• cesium
• elementary chemical reactions
• activation energies
• rate constants
• computational chemistry
• Gamess
• non-empirical molecular orbital theory
• transition state theory
• first principle