Radon index of a local administrative unit.

The determination of radon-prone areas is usually based on indoor radon data and on the prognosis of the occurrence of houses exceeding the action level. However, the sample of houses in the survey must be representative and large enough, which is not easy to fulfill. Despite this, the determination of localities with high radon risk is useful not only for planning of indoor radon surveys, but also mainly for predicting the risk in newly built houses.

Estimates of the annual average indoor radon concentration in Telecí in the Czech Republic.

Indoor radon concentrations are subject to diurnal and seasonal variations. In order to obtain an unbiased estimate of the annual mean radon concentration, measurements made over periods less than 12 months have to be adjusted accordingly. In this paper, hourly radon measurements from one uninhabited rural house in Telecí in the Czech Republic have been analysed.

Radon programmes and health marketing.

Being aware of negative health effects of radon exposure, many countries aim for the reduction of the radon exposure of their population. The Czech radon programme was commenced >20 y ago. Since then experts have gathered a lot of knowledge, necessary legislation has been enacted, tens of thousands of inhabitants have been offered free measurement and subsidy for the mitigation.

1st International comparison measurement on assessing the diffusion coefficient of radon.

Radon diffusion coefficient is a material parameter which is usually used in the radon mitigation measures design. There are different approaches used for radon diffusion coefficient measurement and assessment. The International comparison measurement which was jointly organised by National Radiation Protection Institute and Faculty of Civil Engineering CTU Prague in 2009 and 2010 has registered 11 laboratories from all over the world.

Interaction of radon and smoking among Czech uranium miners.

The study is based on a case-control study nested within a cohort study (11 000 miners and 1074 lung cancers). The controls were individually matched by year of birth and attained age. Smoking data were collected in person or from relatives of deceased subjects or from medical files.

Results of the 2010 National Radiation Protection Institute intercomparison of radon and its short-lived decay product continuous monitors.

During the Sixth European Conference on Protection Against Radon at Home and at Work held in autumn 2010 in Prague, the first intercomparison of continuous radon and its short-lived decay product monitors was organised and held by the Natural Radiation Division of the National Radiation Protection Institute (NRPI) in Prague. Eight laboratories submitted eight continuous radon monitors, two electronic monitors, three passive integral systems based on charcoal and three continuous radon short-lived decay product monitors. The intercomparison included exposures to both the radon gas concentration and equivalent equilibrium radon concentration (EEC) under different ambient conditions similar to the ones in dwellings.

A review of exposures to radon, long-lived radionuclides and external gamma at the Czech uranium mine.

This paper presents the results of the personal exposure monitoring conducted in the RoŽná uranium mine in the Czech Republic. In this mine, which has been operated since the late 1950s, personal ALGADE dosemeters have been used since 1998. A group of 600 miners employed during the period 2000-09 has been analysed.

Indoor and soil gas radon simultaneous measurements for the purpose of detail analysis of radon entry pathways into houses.

Detailed knowledge of radon transport mechanisms from the subsoil into the indoor environment is essential for the correct interpretation of results of short-term indoor radon measurements and for proper and effective design of radon mitigation systems. Radon transfer factor time variations have been studied based on simultaneous continuous indoor and soil gas radon measurements within the framework of complex radon diagnosis of individual buildings. In this context, the key influencing factors have been identified and analysed in order to provide satisfactory explanation on radon entry variations under different measurement conditions.

Significance of independent radon entry rate and air exchange rate assessment for the purpose of radon mitigation effectiveness proper evaluation: case studies.

Two new single-family houses identified as insufficient with regard to existing radon barrier efficiency, have been selected for further examination. A complex set of radon diagnosis procedures has been applied in order to localise and quantify radon entry pathways into the indoor environment. Independent assessment of radon entry rate and air exchange rate has been carried out using the continuous indoor radon measurement and a specific tracer gas application.

Content of uranium in urine of uranium miners as a tool for estimation of intakes of long-lived alpha radionuclides.

Uranium in the urine of 10 uranium miners (hewers), 27 members of general population and 11 family members of miners was determined by the High-Resolution ICP-MS method. Concentration of uranium in urine of the miners was converted to daily excretion of (238)U under the assumption that the daily excretion of urine is 2 l and compared with the modelled excretion of (238)U. Daily excretion of (238)U was modelled using input data from personal dosemeters from a component for measurement of intake of long-lived alpha radionuclides.

NaCl as a retrospective and accident dosemeter.

NaCl is a cheap and widely available material. This study investigated the potential of NaCl in the form of a household salt as a retrospective and accident dosemeter using optically stimulated luminescence (OSL). Samples of the investigated household salt were stimulated using blue light of linearly modulated power.

Twelve years of follow up of cases with old 241Am internal contamination.

A group of workers internally contaminated with Am have been followed for about 12 years. The source of contamination was AmO2 powder used for production of AmBe neutron sources and other applications. The production of some radionuclide sources included chemical treatment of the original material, which transformed the americium into the nitrate, but mostly powder metallurgy was used for production of sources for smoke detectors.

Field tests using radioactive matter.

During recent years, the assessment of possible radiological consequences of a terrorist attack associated with a release of radioactive substances (RaS) has been in the focus of interest of emergency preparedness and radiation protection specialists, as well as experts dealing with the dispersion of harmful substances in the atmosphere. Suitable tools for these analyses are applications of mathematical and physical models and simulation of this attack under 'realistic' conditions. The work presented here summarises the results of four tests, in which a RaS (a Tc-99 m solution) was dispersed over a free area with the use of an industrial explosive.

Testing of a thermoluminescent personal dosimeter at interim storages for spent nuclear fuel.

The National Radiation Protection Institute in Prague is about to use a commercially available multi-element whole-body thermoluminescence dosimeter for its radiation personnel. During the phase of practical verification of the method, the dosimeter was tested, among others, in mixed neutron-photon fields in the area of interim storages for spent nuclear fuel of the Czech nuclear power plant Dukovany. The testing was made with the intention to get information about accuracy of H(p)(10) determination for cases when no site-specific calibration is available or neutron spectra are not known.

Further results in search for transuranium elements in effluents discharged to air from nuclear power plants.

In this work we present data on transuranium nuclides Pu, Pu, Am, Cm and Cm in effluents discharged to air (activity concentrations and annually discharged activities of individual radionuclides) from 7 stacks in 2004-2009. In the effluents discharged to air from one stack low activities of transuranium nuclides were observed throughout the studied period. Transuranium nuclides had been discharged to air from this stack also in previous years since 1996 when defect in the cladding of a fuel element and consequent contamination of the primary circuit occurred.

Low level air radioactivity measurements in Prague, Czech Republic.

Activity concentrations of radionuclides in the atmosphere have been monitored for over 21 years in the Czech Republic, at present at 10 sampling sites. Results of long-time observation of the radionuclides (137)Cs, (7)Be, (210)Pb, (22)Na, (40)K, (238)Pu, (239,240)Pu, (90)Sr, (85)Kr and (14)C and statistical analysis of the data from the monitoring site in Prague are given in the paper. In 2007 mean activity concentrations of monitored radionuclides at Prague monitoring site in Bq/m(3) were: (85)Kr, 1.

Low background shielding of HPGe detector.

National Radiation Protection Institute in Prague is equipped with 14 HPGe detectors with relative efficiency up to 150%. Steel shielding with one of these detectors (relative efficiency 100%) was chosen to be rebuilt to decrease minimum detectable activity (MDA). Additional lead and copper shielding was built up inside the original steel shielding to reduce the volume of the inner space and filled with nitrogen by means of evaporating liquid nitrogen.

Long term monitoring of 137Cs in foodstuffs in the Czech Republic.

This work presents the results of (137)Cs content long-term monitoring (1986-2007) in selected groups of foodstuffs. The data in the period of 1992-2007 were roughly log-normally distributed (beef, pork, milk). The more detailed statistical evaluation in this period of time was performed.

Plutonium isotopes in surface air of Prague in 1986-2006.

Monitoring of 239,240Pu in surface air of Prague started in 1986 in connection with the Chernobyl accident. Measurable activities of 10-28 microBq m(-3) were found from 29 April 1986 to 5 May 1986. In the most of the monitoring periods of 1987-1996, activities of 239,240Pu in air were not measurable.

QA programme for radon and its short-lived progeny measuring instruments in NRPI Prague.

To subserve the institutional research and tasks coming out from the Czech National Radon Programme, a new QA programme to calibrate all the known types of devices that measure radon and its short-lived progeny was developed at the Department of Radon mobile group of the National Radiation Protection Institute (NRPI) at Prague. The programme also included calibration of instruments measuring a unique quantity of unattached and attached fractions of short- lived radon progeny Generally, NRPI declares estimation of radon concentration during all routine calibration measurements with an overall uncertainty <5% (one sigma) and of equilibrium-equivalent radon concentration with an overall uncertainty <10% (one sigma). The results of the comparative measurements of the unattached and attached fractions of each short-lived radon progeny carried out with a comparing continuous monitor Fritra 4 in the German reference radon chamber at PTB Braunschweig indicated an acceptable level of agreement, up to 10%.

Radon programme: presence and future.

An overview of radon programme experience is presented. The paper summarises broad topics concerning radon issue: philosophy of radon policy, radon measurements strategies with respect to indoor radon variation, progress in radon measurement of an individual house (radon diagnosis), national programmes, the role of preventive measures and interventions with respect to existing and future exposure and knowledge of radon risk, problems of remediation strategies, radon mapping process and sense of delineation of radon prone areas, public awareness on radon issue and publicity campaign. Some research activities are proposed aiming at effective solutions for radon issues in the future.

Radon in context of natural radiation exposure: the Czech experience.

Radon issue should be seen in the context of other human exposures and harms. The range of doses from the internal (inhalation and ingestion) and external exposure pathways is presented. Indoor radon regulation is compared with regulation of other natural exposures.

Cost-effectiveness of countermeasures against radon in the Czech Republic: preliminary report.

The cost-effectiveness of remedial and preventive countermeasures against indoor radon in the frame of the Czech Radon Programme is preliminarily estimated, resulting in 72 700 CZK and 194 000 CZK per y of life gained by remediation and prevention, respectively, (exchange rate approximately 28 CZK/EUR).

Detection properties of a measuring system for a continuous soil radon concentrations monitoring.

The continual soil-gas radon concentration measurements are absolutely crucial for a reliable assessment of radon entry characteristics into the indoor building environment. For this purpose, a new detection system (a continuous monitor RM-3) was developed and tested. The detection principle of the monitoring device is based on an airflow ionisation chamber operating in a current mode.

Dose conversion of radon exposure according to new epidemiological findings.

In 1993, ICRP-65 recommended that dose conversion of radon exposure should be based on the comparison of detriments between radon exposure and effective dose. The lifetime detriment from the radon exposure was projected according to the epidemiological studies of uranium miners then available. The projection model (GSF) was multiplicative with temporal and age-at-exposure modification.