CFD based simulation of thoron ((220)Rn) concentration in a delay chamber for mitigation application

Area of Science:

• Radiological physics
• Nuclear engineering

Background:

• Radon-220 (Rn), or thoron, release poses radiological risks in thorium fuel cycle occupations.
• Effective control strategies are essential for occupational exposure reduction.

Purpose of the Study:

• To investigate the efficacy of the Delay Volume Technique for mitigating Rn release.
• To validate Computational Fluid Dynamics (CFD) simulations against experimental data for Rn mitigation.

Main Methods:

• Experimental setup using a 0.5 m³ cubical chamber with a Rn source and measurement system.
• Systematic variation of flow conditions and inlet-outlet positions to determine Rn transmission factors.
• Computational Fluid Dynamics (CFD) modeling to simulate Rn transport and mixing within the chamber.

Main Results:

• Rn transmission factor was experimentally determined under various flow conditions and configurations.
• CFD simulations accurately predicted experimental results, validating the model's predictive capability.
• Flow dynamics and inlet-outlet placement significantly impact Rn mitigation within the delay volume.

Conclusions:

• The Delay Volume Technique, when optimized using CFD, offers an effective method for Rn mitigation.
• CFD modeling is a reliable tool for predicting Rn behavior in delay chambers, outperforming uniform mixing models.
• Optimized chamber design and flow control are crucial for minimizing occupational Rn exposure.