Numerical Simulation Study on Hydrogen Accumulation and Explosion in Radioactive Gas Decay Chamber

Area of Science:

• Nuclear Engineering
• Chemical Engineering
• Safety Analysis

Background:

• Nuclear reactors produce a mixture of gases including hydrogen, nitrogen, oxygen, and radioactive gases during operation.
• These gases are stored under pressure in a decay chamber, posing potential safety risks.
• Understanding hydrogen behavior in this environment is crucial for reactor safety.

Purpose of the Study:

• To investigate the accumulation and explosion characteristics of hydrogen within mixed gases in a reactor decay chamber.
• To analyze the impact of initial hydrogen concentration and operating pressure on hydrogen buildup and explosion potential.

Main Methods:

• Utilized numerical simulation methods to model gas dynamics and hydrogen accumulation.
• Simulated hydrogen behavior under varying initial concentrations and decay chamber pressures.

Main Results:

• With an initial hydrogen volume concentration of 0.2%, concentrations reached up to 4% in 1.61 hours and 30% in 16.79 hours.
• Hydrogen concentration was found to be highest at the top of the decay chamber.
• Increased operating pressure in the decay chamber significantly elevated the maximum hydrogen explosion pressure, reaching up to 7.110 MPa.

Conclusions:

• Hydrogen accumulation and potential for explosion are significant concerns in nuclear reactor decay chambers.
• The rate of accumulation and the severity of potential explosions are dependent on initial hydrogen concentration and system pressure.
• Findings highlight the need for robust safety protocols and monitoring systems for hydrogen management in nuclear facilities.