The important information in this chapter is summarized below.

Effects of Radiation on Water Chemistry (Synthesis) Summary

The intense radiation inside the core of an operating nuclear reactor produces several chemical effects on the reactor coolant itself and on substances dissolved in the coolant. Radiation causes pure water to decompose into H₂ and O₂. The decomposition is suppressed by adding excess hydrogen.

Excess hydrogen is added to suppress the decomposition of reactor water. It also reacts with any oxygen that enters the reactor coolant system, usually as a component of air in makeup water, provided the amount of oxygen is not excessive. If the amount of oxygen is more than enough to deplete the hydrogen, the excess oxygen reacts with nitrogen (also a component of air) and forms nitric acid. In the case of addition of very large amounts of air, the amount of nitric acid produced may be more than enough to neutralize the normally basic coolant and cause it to become acidic.

Radiation induces the combination of N₂ and H₂ to form ammonia, although the extent of this reaction is small and usually has a negligible effect on the pH of reactor coolant. All of the reactions in this chapter are reversible and reach an equilibrium state under normal operating conditions. Changes in the concentrations of any of the reactants disturb the equilibrium and causes the reaction to shift in the direction which restores the equilibrium.

Radiation also produces several nuclear reactions in reactor coolant. The products and , of two of these reactions, contribute radioactivity to the reactor coolant, adding significantly to the shielding requirements for nuclear reactors. Others, and, are also major contributors to the radioactivity in reactor coolant.