Showing papers by "Norwegian Radiation Protection Authority published in 2006"

Radiation exposure to family members of patients with thyrotoxicosis treated with iodine-131.

Abstract: Purpose The purpose of this study was twofold: (1) to measure the radiation exposure to family members of out-patients with thyrotoxicosis treated with radioiodine, 131I, using the recommendations from the European Commission (EC) guidance and age-specific periods for behaviour restrictions; (2) to use the results to identify necessary restrictions to ensure recommended dose constraints.

Paternal occupational exposure to radiofrequency electromagnetic fields and risk of adverse pregnancy outcome

Abstract: Background: During the last decades, public concern that radiofrequency radiation (RFR) may be related to adverse reproductive outcomes has been emerging. Our objective was to assess associations between paternal occupational exposure to RFR and adverse pregnancy outcomes including birth defects using population-based data from Norway.

Modelling solar UV radiation in the past: comparison of algorithms and input data

Abstract: The objectives of the COST action 726 are to establish long-term changes of UV-radiation in the past, which can only be derived by modelling with good and available proxy data To find the best available models and input data, 16 models have been tested by modelling daily doses for two years of data measured at four stations distributed over Europe The modelled data have been compared with the measured data, using different statistical methods Models that use Cloud Modification Factors for the UV spectral range, derived from co-located measured global irradiance, give the best results

Plant and vegetation preferences for a high and a moderate yielding Norwegian dairy cattle breed grazing semi-natural mountain pastures

Abstract: Plant and vegetation preferences of two Norwegian cattle breeds grazing semi-natural mountain pastures were studied for two weeks at two farms during one summer. Two rather different grazing sites gave the opportunity to study the two breeds at different pasture qualities, as well as to test if there is any interaction between breeds and study sites. Each of the two herds consisted of the old, moderate yielding Norwegian dairy breed Blacksided Tronder and Nordland Cattle (STN) and the modern, high yielding dairy breed Norwegian Red (NRF). In order to measure the plant preferences of the animals, faeces samples were collected and analysed for plant fragments. In addition, GPS-data showed the terrain chosen by the herds, and vegetation maps were drawn to find the connections between the grazed vegetation and plant preferences. The study shows that on nutrient and especially species rich vegetation growing on base and nutrient rich soil, as at the first study site (Skabu), the plant species, plant genera and plant groups analysed for in the faeces samples indicate that both the STN and NRF breeds graze very much the same vegetation. However, the results from the second study site (Valdres), where the soil is less fertile, the plant species diversity is lower and the plant species distribution less uniform, the moderate yielding NRF breed seems to cover its higher nutritious requirements by grazing in areas with more nutrient rich vegetation compared to the lower yielding breed, STN. grazing preferences / cattle / intensive and extensive breeds / pasture management / semi- natural grasslands

Environmental modelling: Modified approach for compartmental models

Abstract: Compartment modelling is used for evaluation of radiological consequences and dispersion of radionuclides in the marine environment. One of the general features of the compartment modelling is an instantaneous mixing of contaminants in the ocean. The influence on radionuclide dispersion in the marine environment and radioecological assessment of the developed modified approach for compartment modelling with non-instantaneous mixing of contaminants in oceanic space is discussed. New modifications of the model (calculations of doses to biota and ice transport of radionuclides) underline the significance of the modified approach. Simulations provided by the modified approach indicate that the algorithm with non-instantaneous mixing in oceanic space can predict the different time trends for ice and water transport in the Arctic Ocean (for instance, more rapid transport of contaminants by ice through the Kara Sea to the Fram Srait in comparison to water transport).

Russian nuclear power plants for marine applications

Abstract: In order to establish a systematic approach for future proliferation and environmental analyses of Russia's marine nuclear reactor systems, this paper summarizes and analyzes the available open-source information on the design properties of reactor systems and nuclear fuels. The most distinctive features of Russian marine reactor development are pointed out, and similarities and differences between Russian military and civilian reactor systems and fuel are discussed. Relevant updated information on all Russian vessels using nuclear propulsion is presented in Annex I. The basic analytic division in this paper follows vessel generations first to third generation; and reactor types PWR and LMC technology. Most of the available information is related to nuclear icebreakers. This information is systematically analyzed in order to identify stages in the development of Russia's civilian naval nuclear reactors. Three different reactor models are discussed: OK-150, OK-900 and KLT-40, together with several versions of these. Concerning military reactors, it is not possible to identify characteristics for the individual reactor models, so the basic division follows vessel generations first to third generation. From the information available, however, it is possible to identify the main lines along which the design of submarines of especially the first and the second generation has been made. The conclusions contain a discussion of possible implications of the results, in addition to suggestions for further work. (au)

Assessment of the discharge of NORM to the North Sea from produced water by the Norwegian oil and gas industry

Abstract: In order to obtain a reliable estimate of the discharge of NORM (Naturally Occurring Radioactive Materials) to the North Sea from the Norwegian oil and gas industry, produced water from 41 Norwegian offshore platforms has been sampled during a five-month period from the autumn of 2003 to early 2004 and analysed for 226 Ra, 228 Ra and 210 Pb. Together with data on the volume of produced water discharged from each production platform, the total activity of radium discharged to the North Sea in 2003 has been estimated. Activity concentration of 226 Ra and 228 Ra in the samples ranged from below the detection limit (0.3–1.3 Bq l −1 ) up to 16 and 21 Bq l −1 , respectively. For 210 Pb, all results except one were below the detection limit (0.2–1.5 Bq l −1 ). For some of the platforms, short-term variations in the activity concentration were observed. The discharge of 226 Ra and 228 Ra through produced water in 2003 from the Norwegian oil and gas industry into the North Sea was estimated to be 440 GBq and 380 GBq, respectively. Dividing the total discharged activity by the total volume of produced water discharged in 2003 gives an average activity concentration of 3.3 Bq l −1 for 226 Ra and 2.8 Bq l −1 for 228 Ra in produced water from the Norwegian continental shelf.

Diurnal discrepancies in spectral solar UV radiation measurements.

Abstract: Unexpected diurnal discrepancies between high-quality spectroradiometers were observed during the 2000 Nordic Ozone Group Intercomparison campaign. The spectral ratios of the irradiances showed a diurnal variation of 2–9%. This cannot be explained by the nonideal angular response of the instruments’ input optics in one plane (cosine effect). Instead, by using a radiative transfer model, we show that differences in the angular response in four azimuth planes have the potential to bias the measured data by up to 4.4% (azimuth effect). Other relevant factors are also discussed and quantified and are shown to be significant when diurnal changes in radiation are explained by environmental factors, or when measured data are compared with model or satellite data. Again, intercomparison campaigns have the potential to reveal errors that would otherwise remain undetected. © 2006 Optical Society of America OCIS codes: 260.7190, 120.6200, 120.5630.

Inventory and source term evaluation of russian nuclear power plants for marine applications

Abstract: This report discusses inventory and source term properties in regard to operation and possible releases due to accidents from Russian marine reactor systems. The first part of the report discusses relevant accidents on the basis of both Russian and western sources. The overview shows that certain vessels were much more accident prone compared to others, in addition, there have been a noteworthy reduction in accidents the last two decades. However, during the last years new types of incidents, such as collisions, has occurred more frequently. The second part of the study considers in detail the most important factors for the source term; reactor operational characteristics and the radionuclide inventory. While Russian icebreakers has been operated on a similar basis as commercial power plants, the submarines has different power cyclograms which results in considerable lower values for fission product inventory. Theoretical values for radionuclide inventory are compared with computed results using the modelling tool HELIOS. Regarding inventory of transuranic elements, the results of the calculations are discussed in detail for selected vessels. Criticality accidents, lossof-cooling accidents and sinking accidents are considered, bases on actual experiences with these types of accident and on theoretical considerations, and source terms for these accidents are discussed in the last chapter.

International intercomparison of multiband filter radiometers in Oslo 2005

Abstract: Multiband filter radiometers (MBFRs) are extensively used in national networks for UV climate monitoring and information to the public about the potential risk of solar UV exposure. In order to provide an international, uniform expression of the Global UV index measurements, a harmonized calibration scale is needed. In this paper we present the results of the first international intercomparison of MBFRs held in Oslo in 2005. The purposes are to evaluate the UV-index scale of different radiometers and to provide a harmonized UV-index scale based on the radiometers individual directional and absolute spectral response functions. In total 43 MBFR radiometers and 4 high resolution spectroradiometers were assembled, representing UV-monitoring networks operated by institutions in US, Spain, Greece, Poland, Belgium, UK, Austria, Norway, Sweden and Finland. The radiometers are operating worldwide, with stations in the Antarctica and Arctic, North- and South-America, Africa, Europe, Middle-East and Nepal. All sky conditions were realized during the campaign period. The agreement between the users' own processed UVI and the reference is generally very good; within ±5% for 22 out of 26 data sets (75%) and ±10% for 23 out of 26 (88%). Solar zenith dependent discrepancies and drift in the users' UVI scales is seen, but the performance of most radiometers is generally very good. All the objectives planned for the intercomparison were fulfilled and the campaign considered a success.

Area Specific Stripping of lower energy windows for AGS and CGS NaI systems

Abstract: The report describes the results from a NKS (Nordic Nuclear Safety Research) project aiming at examining the possibilities for extracting stripping factors for Airborne Gamma-ray Spectrometry (AGS) data and Carborne Gamma-ray Spectrometry (CGS) data directly from the recorded set of data, i.e. without having to calibrate the detector systems on beforehand. The project – NKS project ASSb has been carried out between 1 August 2004 and 31 March 2005 by a research group composed of persons from Technical University of Denmark (DTU), Danish Emergency Management Agency (DEMA), Geological Survey of Sweden (SGU), and Norwegian Radiation Protection Authority (NRPA). The AGS and CGS data sets used for the project were recorded by SGU, DEMA, NGU (Geological Survey of Norway), and SSI (Swedish Radiation Protection Institute). Most of the project effort has been directed towards analysing AGS and CGS data with point source signals recorded at the Barents Rescue 2001 LIVEX exercise at Boden in Sweden. Possibilities and limitations for the method have been identified