Radiolytic Environments in Boiling Water Reactor Cores

Abstract

Radiolytic, environments in the BWR primary system were evaluated by using a theoretical model. Reactor core was divided into two regions, boiling and by-pass (non-boiling) channels. The major findings are summarized as follows:

(1) Under normal operation without hydrogen addition, dissolved hydrogen and oxygen concentrations had their maximum values at the height where boiling started. Their concentrations in the boiling channel were lower than those in the by-pass channel because of hydrogen and oxygen release from liquid phase to gas phase.

(2) The most efficient oxygen suppression by hydrogen addition was expected in the non-boiling regions of the reactor core where injected hydrogen was confined in the liquid phase.

(3) When the bulk decomposition of water in the reactor core is represented by

the coefficient decreased as hydrogen injection rate increased, but B hardly changed at a low hydrogen addition rate.

KEYWORDS:

• boiling
• BWR type reactor
• by-pass channel
• hydrogen
• hydrogen peroxide
• oxygen
• radiolysis
• reactor cooling
• reactor core
• systems