The effect of an air cleaner on 220Rn progeny atmospheres has been studied in a Radon/Thoron Test Facility (RTTF) of the walk-in type. The air cleaner consists basically of a fan and a special filter material sandwiched between two metal screens, to which an electric field is applied. The filter is of the polarized media type and uses fibre glass as material. The fan and filter system are housed in a metal case. Air is drawn from the back of the case by means of the fan and forced through the 'electrical' filter where removal of 220Rn progeny occurs. Radon-220 progeny 'depleted' air is discharged at the top of the device. Tests were conducted in 220Rn/220Rn progeny atmospheres when the air cleaner was operating, and when it was turned off. Very pronounced effects were observed during the operation of the device, namely: a dramatic decrease in the 220Rn progeny concentrations and the total aerosol concentration, as well as a large increase in the 220Rn progeny unattached fractions and the plate-out of these radionuclides on the walls of the RTTF. The air cleaner has potential in industrial applications, which should be explored.
A monazite sample extracted from Western Australia mineral sands has been characterized. The monazite in powder form, was injected into the Long-Lived Radioactive Dust Test Facility (LLRDTF) at the Elliot Lake Laboratory. The LLRDTF is a multi-purpose experimental facility designed, among other things, for the evaluation of radioactive dust instrumentation and the characterization of Long-Lived Radioactive Dust (LLRD). The following characteristics of the monazite sample were measured: dust mass versus particle size, alpha-particle activity versus particle size, radionuclide composition, electrical charge versus particle size, and 222Rn and 220Rn emanation from the sample. Cascade impactors were used for particle size and long-lived radioactivity characterization. Alpha- and gamma-spectrometry were employed for radionuclide identification. Special methods were used to measure the emanation of 222Rn and 220Rn from the monazite sample. The data obtained is of interest for dose estimation calculation purposes in the mineral sands industry.
A technical evaluation of four 222Rn progeny measuring instruments has been conducted. The evaluation has been carried out under laboratory controlled conditions and at several locations in an underground uranium mine. The laboratory evaluation consisted of a thorough study of the behaviour and performance of the instruments under a wide variety of environmental conditions such as 222Rn gas concentration, 222Rn progeny concentration, temperature, relative humidity, aerosol concentration, and gamma-field exposure. The four instruments tested were the Pylon WL-1000C, the MDA IWLM-811, the MIMIL IIM, and the EDA WLM-30. The readings of the instruments were compared with a widely accepted 222 -m n progeny concentration measuring method, namely, the Thomas-Tsivoglou method. Two variables affected two instruments significantly, namely, under high aerosol concentration conditions, one of the instruments (EDA WLM-30) ceased to operate because of filter loading. The other variable was gamma-field exposure which affected another instrument (MDA-811) adversely. The instruments were rated according to several criteria. The overall best performer was the MIMIL IIM, although other instruments also fared quite well under a variety of experimental conditions.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.