title: CFD based simulation of thoron ((220)Rn) concentration in a delay chamber for mitigation application.
abstract: The release of (220)Rn gas (conventionally referred to as thoron) is an issue of concern from the radiological point of view for occupational environments pertaining to the thorium fuel cycle. Studies for understanding its release and developing systems to control it are crucial for exposure control research. A thorough study of the "Delay Volume Technique" for mitigation of (220)Rn has been carried out. Experiments have been carried out with (220)Rn source and associated measurement system in a cubical chamber (delay chamber) of 0.5 m(3) volume. For different flow conditions and inlet-outlet positions, (220)Rn transmission factor has been obtained. Computational Fluid Dynamics (CFD) technique has been employed for these experimental conditions and the simulated transmission factors have been compared. The results show that the flow and the position of the inlet and outlet play an imperative role in the transportation, mixing and subsequent mitigation of thoron inside the chamber. Predictive capability of CFD technique for such delay volume experiments has been validated in this work. A comparison has been made with uniform mixing model and it is found that the results of simulation differ appreciably from that of uniform mixing model at the tested flow regime.
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: T K
authors.initials: TK
authors.lastname: Agarwal
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: B K
authors.initials: BK
authors.lastname: Sahoo
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: J J
authors.initials: JJ
authors.lastname: Gaware
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
authors.forename: M
authors.initials: M
authors.lastname: Joshi
authors.affiliation: Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. Electronic address: bsapra@barc.gov.in.
authors.forename: B K
authors.initials: BK
authors.lastname: Sapra
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000032:analysis*; D057446:Hydrodynamics; D008962:Models, Theoretical; D011834:Radiation Monitoring; D011886:Radon / Q000032:analysis*
chemical_list: D000396:Air Pollutants, Radioactive; D011886:Radon
keywords: Delay chamber; Mitigation; Model; Simulation; Thoron