Safety aspect concerning radiolytic gas generation in reactors

Area of Science:

• Nuclear Engineering
• Radiochemistry
• Chemical kinetics

Background:

• Water radiolysis generates hydrogen (H2) and oxygen (O2) in nuclear reactors.
• Accidents can introduce other hydrogen sources, but oxygen primarily comes from radiolysis or air contact.
• Combustible H2/O2 mixtures form above 4% H2/D2 concentration in air-saturated conditions.

Purpose of the Study:

• To investigate the fundamental principles of water radiolysis.
• To analyze H2/D2 and O2 generation via radiolysis.
• To apply these principles to nuclear reactor operating and accident scenarios.

Main Methods:

• Review of water radiolysis mechanisms.
• Application of radiolysis principles to reactor conditions.
• Analysis of hydrogen and oxygen production rates.

Main Results:

• Radiolysis is a significant source of H2/D2 and O2 in water-cooled reactors.
• Oxygen generation is limited to radiolysis or air ingress during accidents.
• Formation of combustible mixtures is possible but dependent on specific conditions.

Conclusions:

• The study examined H2/D2 and O2 generation from water radiolysis in reactors.
• Accident scenarios were analyzed concerning radiolysis-induced risks.
• The likelihood of a radiolysis-driven nuclear accident is considered highly improbable.