This paper presents a history of the development of a formalized training and technology transferprogram for radon testers and mitigators in the United States. It explores the experiences andchallenges of the last fifteen years in providing training to an emerging radon industry so that they, inturn, can provide high-quality measurement and mitigation services to the general public.
Measurements of indoor radon (222Rn) concentrations were carried out by using LR-115 II solid statenuclear track detectors (SSNTD). One hundred forty detectors were placed randomly in Patras housesfor two periods of three months exposure, from December 1996 to November 1997. The observedmean radon values compared with the standard recommended values are low, while the maximumrecorded value is found to be within the limits. The influence of seasonal variation as well thedistance from the ground on radon level were also investigated.
The use of two mapping methods, kriging and moving average, in mapping the indoor radon risk, isinvestigated. Both methods are applied to three databases: simulated radon data, data collected inSouthern Belgium with low sampling density, and data collected in Luxembourg. We use commercialsoftware (SURFERR 6) for kriging, as well as softwares developed by the authors, especially for the radoncase, for kriging and for moving average. Simulated data prove to be very useful in this context. Weconclude that kriging as implemented in SURFERR 6 may not be well adapted to radon mapping.
Two methods for determining the 222Rn diffusion coefficient in building materials are presented.Experimentally, the measurement of radon release rates under well-controlled conditions, using aflush and adsorption technique, underlies both methods. However, the theoretical principle of thetwo methods differs. The first method uses samples with a cubical or rectangular geometry andhas, as a prerequisite that a 100% radon tight surface covering method is available.
The International Commission on Radiological Protection (ICRP) recommends the use of a singleconversion factor, derived from epidemiological studies of exposure to uranium miners, for thedetermination of the effective dose from inhalation of radon progeny. Dosimetric models of radonprogeny inhalation predict that the dose conversion factors (DCF) are dependent upon the form ofthe radon progeny activity size distribution. The measurement of these activity size distributions isdifficult and an alternative approach has been proposed.
Historic low-level radioactive wastes are located in Port Hope, Ontario, Canada. The radioactivecontaminants, mainly radium-226 and natural uranium, were deposited by a radium refining industrythat operated within the town from the 1930s to the 1950s.A national program for the assessment and remediation of communities affected by radioactivecontamination was initiated in 1975 by a Federal-Provincial Task Force on Radioactivity andterminated in 1982.
Three different methods were used to measure radon concentration in groundwater near Baia Mare andin other places of touristic interest from Maramures, the northest district of Romania. The majority ofthe samples have been measured using two methods of alpha detection. The Radon Emanometermethod has a sensibility ofl 0.074 Bq/l (2 pCi/l) and it uses a device of Russian provenience. We madeseventy (70) different measurements with this device.
Soil radon concentrations together with climatic and seismic data were continuously observed in theKanto area (Japan). During fall 1998, several typhoons and earthquakes occurred. In the meanwhile,continuous measurements of the following parameters were carried out: air pressure, temperature inthe air and in the soil, humidity in the soil, wind speeds, wind direction, rainfall and earthquakesmagnitudes.Data were analyzed using time-series analysis method, i.e. Correlation and Spectrum Analysis, so asto point out the possible relationship between radon and an environmental variable.
A test-house was realised and equipped with an Active Sub-Slab Depressurization (ASD) systemwith two suction branches. As the active element, a centrifugal fan of power 136 W was used. Thecharacteristic point of operation of the fan was determined as 370 m/h air flow rate, with -120 Papressure drop in each suction branch with respect to the atmospheric pressure. The radon activityconcentration in the sub-slab region (in gravel) was increased by means of a flow-through radongassource of 3.7 MBq activity.
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