[en] In this work it is shown that mosses can be used as bioindicators of the atmospheric fallout resulting from the long term release of fly-ash from coal-fired power stations. It is believed that the 50 years of operation of Ajka Power Plant provided excellent possibilities for some experimental radioecological investigations. Among others, dispersion models and methods for the estimation of doses to members of the public could be well tested in this region

[en] The total dose to the population after a large-scale contamination following a reactor accident or a weapon's fallout greatly depends on the ingestion dose caused by contaminated foodstuff. The contamination of foodstuff on the other hand, depends significantly on the date of deposition in the year as the interception of radionuclides by plants and thus the contamination levels in foodstuff are dominated by the growth stage of plants at the time of fallout. Therefore, the contribution of different foodstuff to the ingestion dose will vary according to the deposition date in the year which greatly influences the countermeasures to be adopted in order to limit population exposure. The ingestion dose is also greatly influenced by the time duration of enhanced contamination levels in the various foodstuffs. The effectiveness of countermeasures therefore also depends significantly on time factors in foodstuff contamination. The paper discusses examples of contamination levels to be expected at different deposition dates throughout the year and the corresponding ingestion dose contribution by various foodstuffs and their influence on proper countermeasures to be adopted. The dose reduction due to different countermeasures on different foodstuffs are compared in particular with regard to the deposition date. It is shown that a few countermeasures on a limited number of foodstuff will reduce the ingestion dose by a large fraction, while measures on other foodstuff would contribute only little to the dose reduction. Emphasis in protection measures should be focused on these few foodstuffs, while the others may be neglected in protection measures without serious detriment

[en] Radon concentration in outdoor air is generally considered as relatively low and can, therefore, be neglected. However, there are particular cases featuring considerable radon concentrations and typical daily hydrographs. Then, it is necessary to incorporate the outdoor air parameters in the calculation of air changes also essentially affecting the energy consumption in a building. In Germany, the requirement not to exceed the upper limit of normal range amounting to 250 Bq/m³ as long-term average value shall be met for common rooms. To ensure this, generally not applicable measures for decreasing concentration are explained

[en] A prototype station for a Radiation Early Warning Network has been designed and set up at the Austrian Research Centre Seibersdorf. This unit was developed to measure all relevant parameters necessary to detect and track radioactive contamination at an early stage. The station consists of the following components: (1) Radiation measuring channel for ambient gamma doserate; (2) meteorological measurement channels for air temperature and humidity, wind direction and wind speed, and precipitation; (3) data processing and storage unit. The system is capable of unattended operation and data acquisition even under adverse environmental conditions. Connection to a central processing platform may be achieved via leased line, dial up over public switched telephone network (PSTN), or radio-frequency transmission. The remote station will continue acquiring and storing data for at least a month, even if the communications link is broken. Multiple stations can be combined to form a network, providing detailed information about radiological and meteorological data at each site. Thus increased ambient radiation levels may be discovered, tracked, and forecasted based on calculations using current and local weather data. Highly sophisticated software for the central processing platform, employing 3-dimensional disperion calculations, yields time projected scenarios of probable dose distributions. This may be used as valuable tool in decision finding based on actual data

[en] The evaluation of occupation radiation exposures (ORE) for Czech Republic during 1975 - 1990 period is presented. The greatest number of workers (about 20000) is controlled by National Dosimetric Service, about 9000 persons is monitored by dosimetric services of the uranium industry and nuclear power plants. ORE are evaluated periodically in intervals of one or three months. Evaluation of ORE to radon and its daughters in the uranium industry is based on combination of the measurement of radon and its daughters concentration in air and the data of the exposure time

[en] Occupational doses have wide variations from zero to high values on the logarithmic scale, according to the workers jobs. However as radiation control programmes constrain higher exposures more, the variation of higher doses changes from log to linear scale, while the structure of lower doses remain. In the paper we analyse the annual effective doses of workers in 3 nuclear power plants of Jaslovske Bohunice using various distribution models. The hybrid-lognormal description of the annual dose distribution makes it possible to assess also the annual collective doses below the adopted recording level. Two methods of analysing the 'lost' occupational collective doses are presented

[en] According to the Western European Calibration Cooperation (WECC) rules and policy, international acceptance and recognition of calibration and measurements certificates, are gained through a permanent programme of interlaboratory comparisons and evaluation of each other's organizations. The series of WECC Interlaboratory comparisons started in 1975. Up to now 53 comparisons have been initiated and 22 of them are now still running. At present, about 800 calibration laboratories have been accredited in the 17 WECC member countries. Through this programme of comparisons, the equivalence of certificates issued by these laboratories has been permanently demonstrated. On the basis of these results a multilateral agreement on mutual recognition of calibration certificates has been signed among nine National Accreditation Bodies

[en] National regulatory authorities usually demand that monitoring instruments are regularly calibrated against reliable reference sources. There are many national and international standards describing the properties and quality of reference sources. National accreditation services (e. g. NAMAS in the UK and DKD in Germany) are authorized to approve laboratories for the supply of traceable reference sources, and sources covered by this arrangement are fully traceable to national standards of radioactivity. Under mutual recognition agreements, the traceability of sources from approved laboratories in one country can also be recognized in other participating countries

[en] The 80-90 percent of the occupational dose contribution during maintenance work is due to activated corrosion products in the Paks NPP. The studying of the movements and deposition of corrosion products provides useful information for dose planning of the specialist involved in the work. Therefore more information about the properties of corrosion products in a WWER type reactor by using both experimental and modelling methods is needed. Dose rate measurement give rather qualitative prediction, but provide very useful information about the whole primary system in regard to the deposition rate of products. In addition to the dose rate measurements the searching of 'hot spot' of deposition can be also applied for. The rapid changes of the activity concentrations in the coolant can be simulated by the compartmental model for the movements of the nuclides Ag-110m and Co-60. The results of modelling based on the measured data prove high probability that the main source of Ag-110m is the reactor core, while Co-60 originates from both the core and outside

[en] Systematic measurements of indoor radon concentrations in all the 730 kindergartens and play schools in Slovenia were carried out. The basic method was direct sampling of air into alpha scintillation cells, but in cases with increased indoor radon concentrations track-etch detectors and alpha spectroscopy were also applied. In 72% of kindergartens and play schools instantaneous indoor radon concentrations were below 100 Bq m^-3, with a geometric mean of 58 Bq m^-3. In 16 cases it exceeded 800 Bq m^-3, with the highest value of 5750 Bq m^-3