222Rn

The Nuclear Engineering Section of the National Technical University of Athens undertook the organisation of a European building material radon exhalation rate intercomparison exercise in the framework of the European Research into Radon In Construction Concerted Action (ERRICCA). The intercomparison started in June 1998 and it was concluded in February 1999. Twenty participants from 13 countries took part. The exercise focused on the radon exhalation rate determination from a concrete slab, specially constructed to produce radon surface flux well below 10 mBqm-2s-1.

Indoor radon concentrations were determined with the use of track-etched detectors and two monitors,both for radon and one for the decay products, in various regions of Greece. Until now, 1137 dwellings have been measured. Some factors, that influence the radon concentration in dwellings, are discussed in this paper. The factors, used in this analysis, were derived from the householders answers to the relevant questions about various physical features of the dwelling. Different statistical methods were used, as the unpaired t-test and the ANOVA method.

The radium distribution of the soil is one important parameter governing radon emanation. The present study’s main objective is to investigate radium distribution in different Swedish soils, using chemical selective sequential extraction, and to compare t

The effectiveness of various insulating materials for limiting radon entry into houses has beeninvestigated experimentally in 90 existing houses and in laboratory conditions. Each material hasbeen evaluated according to several aspects - placeability, durability, tear resistance and diffusionproperties. The results of the radon diffusion coefficients measurement in more than 80 insulatingmaterials are summarized. We have found out that great differences exist in diffusion properties,because the diffusion coefficient varries within four orders from 10-13 m2/s to 10-10 m2/s.

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.

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.