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As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg-1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y-1.

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Radiological Dispersal Devices (RDDs) are designed to disperse radioactive material over a wide area, leading to significant consequences to the environment and public health. This paper discusses the radiological effects of a potential RDD detonation containing 137Cs and 241Am in the commercial area of Busan, South Korea. The assessment, conducted with HotSpot Health Physics and RESRAD-RDD codes, found that summer had the most significant impact, with a maximum total effective dose equivalent (TEDE) of 280 mSv at 100 m and this decreased to 1 mSv at 4.5 km from the detonation point within the time interval of 35 min.

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In Europe, the general obligation to recycle drives for increased reuse of residues containing Naturally Occurring Radioactive Material (NORM). In agriculture, this has led to the reuse of sludge produced by groundwater filtration facilities as a means of fertilization. In the frame of the RadoNorm project, a methodology was developed for dose assessment of agricultural workers and other members of the public living near agricultural fields in which NORM-containing sludge is applied. Appropriate exposure scenarios were identified and modelled for each relevant NORM decay segment of both U-238 and Th-232 series, as well as for K-40. Dose assessments were performed using the software RESRAD-ONSITE with dose coefficients for external and internal exposure taken from the latest publications from the International Commission on Radiological Protection (ICRP). The objective was to develop a generic methodology to quantify exposure and to obtain screening values - so-called Operational Levels (OLs). These OLs pertain to the activity concentration of natural radionuclides (in terms of kBq kg-1) present in sludge that is reused in agriculture, for which dose criterion of 1 mSv year-1 is complied with. OLs can be used as screening tools by an authority/operator, even non-experts in the field of radiation protection. Results showed that the most critical decay segments are Ra-226+ and Ra-228+, for which OLs of the order of 1 kBq kg-1 were estimated. For all the other radionuclides, the calculated OLs are much higher than the activity concentrations typically found in sludge from water treatment facilities, and the radiological impact expected is well-below 1 mSv year-1. The methodology and results of this study could contribute to the update of the Clearance Levels and discharge levels reported in the European guidelines RP 122 Part II and RP 135, respectively.

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PURPOSE: This work will focused on the environmental and radio-ecological impacts occurred on an Egyptian coastal region, based on the radiochemical measurement of 238U, 137Cs, 232Th, 40K. The novelty of the study was cleared by the using of new technique showing the integration of two biological RESRAD models, lead to a probabilistic estimation of the radionuclides bioaccumulation in different consumed marine organisms and determination the probability of human cancer risk at different ages. MATERIAL AND METHODS: The 20 water samples were collected and mounted into clean containers, and their decay products, were measured in Bq.L-1, using different quality assurance tools. The study will used different statistical analysis and different RESRAD modeling codes were used in the study to predict the degree of environmental and radio-ecological impacts at the studied area, this will be helpful in order to define the impacts resulted from the transferring and accumulation of different radionuclides. RESULTS: showed that the highest human dose conversion factor values of (5, 10, 15, with adult ages) were measured in Th-232 (mrem/pCi) while the lowest ingestion conversion factors values were observed in artificial 137Cs. On the other hand the highest values of external risk factor in case of (5, 10, 15 with adult age) were observed in artificial Cs-137(mrem/pCi), while the lowest value of external risk factor with the same ages were observed in U-238. This will lead to continual monitoring of artificial Cs-137 in different marine coastal regions. The arrangement of the bioaccumulation value (BIV) in Bq.kg-1 which being calculated by using RESRAD-Biota in case of crustacean animals will be as follow: U-238 > Th-232 > Cs-137, while the arrangement of BIV in case of fish animals will be: Cs-137 > U-232 > Th-232. On the other hand the arrangement of Internal Dose Conversion factors in case of crustacean animals will be: U-238 > Th-232 > Cs-137. While the arrangement of Internal Dose Conversion factors in case of fish animals will be: Cs-137> Th-232 > U-238. CONCLUSION: RESRAD code's results showed that the arrangement of the bioaccumulation and Dose Conversion factors were depend on the type of marine living organism. RESRAD code also showed that there are increments of the calculated external risk factor values which resulted from the adult than all the infants (5,10 and 15 ages) ages this may be related to the continuous replacement of new human's body cells during the growth stages. The study results showed that, environmental bioaccumulation impacts of the artificial Cs-137 were very effective in both marine living organisms and human as this will support the relation between the ingestion Cs-137 in the body(inside the soft tissues), and the probability of the human cancer risk. On the other hand, study results showed the importance of using RESRAD BIOA code for the EIA's ecological and radiological studies which should be done for any future industrial coastal .projects.

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In this study, the specific activities of 226Ra, 232Th and 40K in the unfired construction materials (solid card bricks, 4-hole bricks, pavement bricks) containing fly ash and bottom ash from a coal-fired thermal power plant in Vietnam were measured using the low-level gamma-ray spectrometer with HPGe detector. Also, the 222Rn concentrations in these materials were analyzed using RAD7 radon monitor and then radon mass exhalation rate and emanation fraction of these materials were calculated. The potential radiological hazards for residents living in the model room made of these materials were evaluated. The average specific activity of 226Ra, 232Th and 40K were found as 67.7, 79.3 and 703.5 Bq kg-1, respectively. The total annual effective dose (due to external gamma exposure and internal radon exposure for resident living in the CEN model room made of the unfired brick samples) was found as 0.9 mSv y-1 which is lower than the worldwide average dose of 2.4 mSv y-1. Calculations from ResRad-Build code showed that the doses due to radon exposure account for from 62.3% (at the first year) to 98.8% (at the next 30 years) of the total gamma and radon dose. Under low air exchange to the outside environment, from the 6th year onwards, the total dose may exceed the average dose value from natural radiation exposure sources.

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This research presents the levels and distribution of 210Po in different sediments of the northeastern coast of the Mediterranean Sea. The 210Po activity concentrations were measured using an alpha spectroscopy system. The activity concentrations of 210Po in the sediment samples were in the range between 20.5 ± 0.7 and 92.8 ± 1.6 Bq kg-1 dw with an average of 48.2 ± 1.4 Bq kg-1 dw. The microorganism-enriched sampling sites (bedrock sites) indicated low 210Po concentration than sandy coastal sites. As a result of these measurements, the RESidual RADioactivity (RESRAD) biota code was applied to calculate the tissue concentration rate (CR), internal dose rate, external dose rate, and total dose rate of the exposed tissues. The total dose rates of aquatic animals were found higher than that of riparian animals. The 210Po sediment resource doses to aquatic and riparian animals were found less than the dose level recommended by International Commission on Radiological Protection (ICRP).

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The study aims to assess long-term radiological exposure risks and effects to both industrial workers and occupants living in the near vicinity of local tailing processing plants. The detrimental effects of licensing exemption were studied by comparing contaminated soil collected from 7 unlicensed-by the Atomic Energy Licensing Board-tailing processing plants with soil from control location. It was found that the average concentration of 226Ra, 232Th, and 40 K for all seven processing plants fell between the range of 0.1 ± 0.0-7.21 ± 0.1 Bqg-1, 0.1 ± 0.0-16.34 ± 0.27 Bqg-1, and 0.18 ± 0.01-1.74 ± 0.01 Bqg-1, respectively, showing observable indication of soil contamination with Technologically Enhanced Naturally Occurring Radioactive (TENORM) material. The annual effective dose was calculated which showed that most samples exceeded the recommended value of the ICRP of 1 mSvy-1 for non-radiation workers. Assessment of radiological hazards in the environment was done by calculating the radium equivalent value; revealing the exposure risk posed by the contaminated soil is substantial. Using the relatable inputs, the RESRAD-ONSITE computed code revealed that the dose due to internal exposure via inhalation of radon gas contributes the most to the overall exposure. The covering of the contaminated soil with a clean layer is effective in reducing external dose but ineffective for radon inhalation. RESRAD-OFFSITE computer code also revealed that the contribution of exposure via contaminated soil in the neighbouring vicinity is below the recommended 1 mSvy-1 threshold but still contributes to a significant amount cumulatively when considering other exposure pathways as well. The study proposes the introduction of clean cover soil as a viable option in reducing external dose from contaminated soil as 1 m of clean cover soil is able to reduce dose exposure by 23.8-30.5%.

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The oil and gas industries are the largest producers of NORM wastes that are continuously generated during production and extraction activities. In addition, an increasing trend is observed in waste production worldwide due to the decommissioning of oil platforms. The problem is that most of these wastes are in activity concentration levels above the exemption and the clearance limits and are being accumulated in storage sites because no repositories exist in Brazil for NORM wastes generated by oil industries. There are regulations for radioactive wastes and for the licensing of repositories for managing wastes with low and intermediate levels of radiation but the current regulations apply only to packaged wastes. Therefore an initial radiological assessment was carried out with the RESRAD-OFFSITE code to show that bulk NORM wastes (not packaged wastes) could be disposed of in repositories near the surface without causing additional risk to the public above the criteria used. The results can also support decision-making by the Regulatory Authority to change the current regulations and allow for the disposal of wastes in bulk form.

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PURPOSE: The protection of endogenous species is one of the important ecological issues in which all the World Environmental Agreements are searching for. The purpose of the study is to calculate the bioaccumulation impacts of some natural radio-nuclides as: Ra-226, K-40 and Th-232 in the selected Egyptian Endogenous Aquatic Red Sea Fusileer fish, Red sea Riparian Turtle and the Red sea Terrestrial Lizard by using RESAD BIOTA version 1.8. MATERIAL AND METHODS: Ten water and sediments samples were collected from different 10 sites, along the inshore of the Egyptian Suez bay beach till El-Zafarna coastal region, as these samples were taken from subsurface (20 cm-1 m). The radioactivity concentrations of some natural radioactivity radionuclides as; 226Ra, 232Th and 40K, which were measured, using gamma-ray spectrometer based on high-purity germanium (HPGe) detector of 40% relative efficiency. RESULTS: The results of the study showed that the radioactivity of some selected natural radionuclides in the selected 10 sites of Suez costal samples were arranged as: K-40 > Th-232 > Ra-226, as this was related to the characteristics of soil and rock precipitation in this zone besides the industrial activates along the selected coastal line zone of Suez bay till Al-Zafrana. On the other hand, it was observed that all the calculated Biota contamination Guide (BCG) values of the selected Egyptian endangerous species (Aquatic, Riparian and terrestrial) animals in the 10 selected sites samples were below the recommended (BCG), as the result, no radioactivity increment being detected at these selected sites. On the other hand, the BCG values of Ra-226 in both water and sediment samples for the selected Egyptian endangerous Aquatic Sea Fusileer Fish were higher than the recommended BCG values in water, while were comply with BGC values of the sediment, while in case of Egyptian endangerous Red Sea Turtle's BCG values were comply with the recommended BCGs in water while were higher than the recommended BCGs values of sediment. In case of the selected Egyptian endangerous terrestrial Lizard its BCG values of Ra-226 were higher than the recommended BCGs in both water and sediment media. While in case of Th-232 it was observed that the BCG values of selected endangerous Red Sea Fusileer Fish were higher than the recommended BCGs in both water and sediment and also the BCG values of selected endangerous Riparian Turtle were also higher than the recommended BCGs of both water and sediment, these results may increase the suitability of the selected Egyptian endangerous Marine, Riparian and Terrestrial species to the different radiological risks. The results showed also the decrement of the radioactivity values of the measured radionuclides in the internal tissue of the Egyptian selected endangerous Red Sea Lizard (Uromastyx aegyptia) than both the selected endangerous Red Sea Turtle and Red Sea Fish species, support the reptiles, which are cold blood animals, and is less affected by gamma radiation than other terrestrial animals.

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Radiometric monitoring of construction materials is required for estimating the interior and exterior exposure to ionizing radiation emitted by terrestrial radioactive elements in building materials. Using gamma-ray spectroscopy, the activity concentrations of 226Ra, 232Th, and 40 K in fifty-two samples from eighteen different building materials commonly used in Erbil city, Kurdistan region, Iraq, were evaluated to assess possible radioactive dangers to human health. The activity concentrations of 226Ra, 232Th and 40 K ranged from 1 ± 0.1 (gypsum board) to 130 ± 11 (granite), 1.3 ± 0.2 (gypsum) to 66 ± 8 (ceramic sample), and 18.74 ± 4 (gypsum) to 1061.708 ± 40 (granite) with an average of 28 ± 5, 20.7 ± 4, and 340.8 ± 18 (average ± standard deviation), respectively. Radiological indicators (activity concentration index, alpha and gamma index, hazard indices, interior absorbed gamma dose rate and the corresponding yearly effective dosage rate, and excess lifetime cancer risk) were computed to assess the health risks associated with these building materials. Consideration was given to the indoor annual effective dosage for common construction materials, the radon surface expiration rate, and the indoor radon concentration. The mean values of activity concentration were then inputted into the RESRAD-BUILD computer software to calculate a resident's long-term radiation exposure. The dosages were measured over a range of 0 to 70 years. From 0 to 30 years, there was a significant change in dosages; however, from 30 to 70 years, the dosages were reasonably consistent. This research demonstrates that granite samples are not safe for dwellings with poor ventilation (especially those without windows). In general, other investigated construction materials in the buildings are deemed safe for the population, since the computed values for these parameters fall within the well-being restrictions or criterion values.

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Despite the fact that disruption of the environment through mining of minerals poses severe radiological hazards, there is a dearth of radiological information from gold mining sites in Nigeria. In this study, state-of- the-art computational tools - RESRAD ONSITE, RESRAD OFFSITE and ERICA were applied to a typical representative artisanal goldmining area for a more comprehensive evaluation of radiological risks associated with artisanal gold mining in Nigeria. The estimated doses received by an offsite receptor is within the radiation basic safety limit, while for onsite receptor it is greater than the basic radiation safety limit. It was observed that onsite dwellers of the artisanal goldmining areas may suffer high cancer burden when compared with the US EPA acceptable levels. For non-human biota, the hazard quotient was greater than unity and the total dose rate per organism was greater than the screening dose rate of 10µGy h-1. It was observed that 232Th and 226Ra were the main contributors to the total dose and the pathways that contributed most to the dose were; external exposure (via direct and airborne radiation from soil and Radon) as well as water independent plant, meat and milk consumption. Therefore, monitoring food production will lead to an informed decision making and risk communication towards sustainable mining will contribute in minimizing the level of the anticipated risks as low as reasonably achievable.

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In response to changing international recommendations and national requirements, a number of assessment approaches, and associated tools and models, have been developed over the last circa 20 years to assess radiological risk to wildlife. In this paper, we summarise international intercomparison exercises and scenario applications of available radiological assessment models for wildlife to aid future model users and those such as regulators who interpret assessments. Through our studies, we have assessed the fitness for purpose of various models and tools, identified the major sources of uncertainty and made recommendations on how the models and tools can best be applied to suit the purposes of an assessment. We conclude that the commonly used tiered or graded assessment tools are generally fit for purpose for conducting screening-level assessments of radiological impacts to wildlife. Radiological protection of the environment (or wildlife) is still a relatively new development within the overall system of radiation protection and environmental assessment approaches are continuing to develop. Given that some new/developing approaches differ considerably from the more established models/tools and there is an increasing international interest in developing approaches that support the effective regulation of multiple stressors (including radiation), we recommend the continuation of coordinated international programmes for model development, intercomparison and scenario testing.

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The objective of the current study is to investigate the natural radioactivity of some building materials, the resulting long-term external and internal effective dose equivalents (EEDE and IEDE) analysis followed by indoor radon measurements, and the assessment of some radiological risk indicators associated with radon exposure. A total of 37 samples of building materials were analyzed with a sodium iodide detector (NaI (Tl)), and the computer code RESRAD-BUILD was used for the analysis of the EEDE and IEDE of the structural elements of the houses (walls and floor). For indoor radon measurements, 140 houses were selected, and in each of them was placed 01 RADTRAK dosimeter. Inhalation dose, total dose, and some radiological risk indicators were calculated. The specific activities of 226Ra, 232Th, and 40K for the overall sampled building materials were found to vary between 10 ± 2-52 ± 7, 10 ± 1-95 ± 10, and 31 ± 1-673 ± 20 Bq kg-1, respectively. The dwelling types with bare brick walls, cement mortar plastered walls, and concrete floors show EEDE and IEDE values well below the recommended limits. The corresponding dwelling type contributions to the measured average indoor radon concentration (42 ± 12 Bq m-3) are 22%, 13%, and 16%, respectively. Inhalation dose resulting from the measured indoor radon concentrations varies from 0.35 to 3.24 mSv y-1 with a mean value of 0.96 ± 0.55 mSv y-1, which represents about 65% of the total dose simulated (1.49 ± 0.88 mSv y-1) by the RESRAD-BUILD code. The overall analysis of indoor radon-related radiological risk indicators shows low levels of risk relative to permissible limits.

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In this study, by considering the Naturally Occurring Radioactive Materials (NORMs) contained in the building materials used in Mahallat, Iran - an area exposed to a high level of natural background radiation - residential scenarios were simulated by applying the computer code RESRAD-BUILD to estimate the long-term Effective Dose rate of three different cases of basic building materials utilized in walls, floors and ceilings. Maximum effective dose rates of between 504 and 1433 µSv yr-1 were calculated in the second case study, tiled cement floor. The highest external and radon doses were also calculated to be 369 and 1064 µSv, respectively. The simulation results revealed that 232Th and 40K contribute the most and least to the indoor dose, respectively. As a result of a sensitivity analysis, it was found that the air exchange rate is a key variable to easily reduce the radiological impacts of building materials. It was also shown that due to the presence of 226Ra, the sensitivity of effective dose to changes in wall thickness was higher than other radionuclides found in the building materials.

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PURPOSE: This study aimed to assess the radiological risk of natural radionuclides (226Ra, 232Th, and 40K) to marine ecosystem biota. MATERIALS AND METHODS: The study site in this was the Mediterranean Sea, Cyprus. With the use of the RESRAD-BIOTA (RESidual RADioactivity BIOTA) code, the tissue concentration, external and internal dose rate of aquatic animals and riparian animals were estimated. RESULTS: The total tissue concentrations of the aquatic animals and riparian animals were simulated at 1.14 × 106 Bq/kg (water media) to 0 Bq/kg (sediment media), and 1.33 × 106 Bq/kg (water media) to 9.79 × 101 Bq/kg (sediment media), respectively. The total dose rate for aquatic animals and riparian animals was ranged from 1.94 × 10-2 to 0 Gray per day (Gy/d) and 1.46 × 10-2 to 7.40 × 10-7 Gy/d, respectively. CONCLUSIONS: Based on the risk assessment of this study, there is no significant impact due to organisms' exposure to natural radioactivity. Although, further consideration of the exposure levels is required due to the potential effects of protracted low-level ionizing radiation.

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The dispersion of radionuclides in dust and inhalation dose rates to the public from the planned remediation of the Ranger uranium mine in the wet-dry tropics of Australia was modelled using RESRAD-OFFSITE. Dust inhalation dose rates were predicted to be highest on the remediated site and decrease with an approximate inverse square to inverse cubic dependence with distance from the site. The annual dose above natural background to a hypothetical individual permanently occupying the remediated site (representing the worst case scenario for radionuclide in dust exposure) was estimated to be 5.3 × 10-3 mSv. The estimated doses from exposure to radionuclides in dust were two to three orders of magnitude lower than those from exposure to 222Rn. A sensitivity analysis showed that source-related and receptor-related model parameters had direct proportional influences on dust inhalation dose rates. Four transport-related model parameters (atmospheric stability class, deposition velocity of particulates, precipitation and wind speed) were also influential and generally had an increasing influence with distance from the source. The results of this study may provide general guidance to similar sites elsewhere on the relative importance of dust versus gaseous 222Rn transport pathways and the relative influence of dispersion modelling parameters on predicted exposures and doses.

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PURPOSE: The purpose of this paper is to evaluate the morbidity excess cancer risk (ECR) due to internal and external exposure to three category levels of natural radionuclides in soil like 238U, 232Th and 40K. Although the exposure rate in soil is low but effect this radiation over time can lead to cancer risk and this risk can be calculated. MATERIALS AND METHODS: Natural activity concentration levels of 40K, 238U and 232Th in soil were selected from last reports in three concentration categories including: low, medium and high levels. The excess cancer risks of three concentration levels were calculated by means of RESidual-RADioactivity (RESRAD) code. RESULTS AND CONCLUSIONS: The calculated average morbidity ECR from 40K, 238U and 232Th in three concentration categories levels in soil were 1.40 × 10-4, 8.56 × 10-4 and 1.35 × 10-3, respectively. This calculation shows that the excess cancer risk value is the highest value in 100 years' time in all categories. Overall ECR from 40K radionuclide was maximal and the highest exposure pathways was through plant pathway; however, these pathway changes over 60 years to the drinking water pathway. The results of this study may be useful to risk assessment and for decision making for public health protection against high-level radiation.

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The dispersion of 222Rn from the planned remediation of the Ranger U mine in the wet-dry tropics of Northern Australia was modelled. Dry and wet season contour maps of 222Rn dose normalised to 226Ra activity concentration in the proposed waste rock substrate on the remediated landform were developed. Three example exposure scenarios were assessed based on an anticipated waste rock 226Ra activity concentration of 800 Bq kg-1. The estimated above-background annual dose from 222Rn to hypothetical receptors at the Aboriginal community at Mudginberri (∼10 km NNW) was 0.005 mSv and at the township of Jabiru (∼7 km W) was 0.033 mSv. The estimated above-background annual dose for the hypothetical worst case scenario, representing a receptor 1 km WNW of the landform centroid during the dry season and at the centroid during the wet season, was 0.13 mSv. Variability analysis on the 20 y meteorological dataset used in the dispersion modelling showed that the dry and wet season 222Rn dose predictions in any single year could be approximately double those of an average year, which suggests that estimates of average 222Rn dose should potentially be doubled if the assessment aim is to demonstrate compliance with the public dose limit.

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This paper presents the environmental radiation risk assessment based on two software program approaches ERICA Tool (version 1.2) and RESRAD BIOTA (version 1.5) to estimate dose rates to terrestrial biota in the area around the largest coal fired power plant in Serbia. For dose rate assessment software's default reference animals and plants and the best estimated values of activity concentrations of 238U, 234U, 234Th, 232Th, 230Th, 226Ra, 210Pb, 210Po, 137Cs in soil were used. Both approaches revealed the highest contribution to the internal dose rate due to 226Ra and 210Po, while 137Cs contributed the most to the external dose rate. In the investigated area total dose rate to biota derived using ERICA Tool ranged from 0.3 to 14.4 µGy h-1. The natural radionuclides exhibited significantly higher contribution to the total dose rate than the artificial one. In the investigated area, only dose rate for lichens and bryophytes exceeded ERICA Tool screening value of total dose rate of 10 µGy h-1 suggested as confident that environmental risks are negligible. The assessed total dose rates for reference animals and plants using RESRAD BIOTA were found to be 7 and 3 µGy h-1, respectively. In RESRAD BIOTA - Level 3, 10 species (Lumbricus terrestris, Rana lessonae, Sciurus vulgaris, Anas platyrhynchos, Lepus europaeus, Vulpes vulpes, Capreolus capreolus, Suss crofa, Quercu srobur, Tilia spp.) representative for the study area were modeled. Among them the highest total dose rate (4.5 µGy h-1) was obtained for large mammals. Differences in the predicted dose rates to biota using the two software programs are the consequence of the difference in the values of transfer parameters used to calculate activity concentrations in biota. Doses of ionizing radiation estimated in this study will not exhibit deterministic effects at the population level. Thus, the obtained results indicate no significant radiation impact of coal fired power plant operation on terrestrial biota. This paper confirms the use ERICA Tool and RESRAD BIOTA softwares as flexible and effective means of radiation impact assessment.

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For the first time, a system for specific consideration of radiological environmental protection has been applied in a major license application in Sweden. In 2011 the Swedish Nuclear Fuel & Waste Management Co. (SKB) submitted a license application for construction of a geological repository for spent nuclear fuel at the Forsmark site. The license application is supported by a post-closure safety assessment, which in accordance with regulatory requirements includes an assessment of environmental consequences. SKB's environmental risk assessment uses the freely available ERICA Tool. Environmental media activity concentrations needed as input to the tool are calculated by means of complex biosphere modelling based on site-specific information gathered from site investigations, as well as from supporting modelling studies and projections of future biosphere conditions in response to climate change and land rise due to glacial rebound. SKB's application is currently being reviewed by the Swedish Radiation Safety Authority (SSM). In addition to a traditional document review with an aim to determine whether SKB's models are relevant, correctly implemented and adequately parametrized, SSM has performed independent modelling in order to gain confidence in the robustness of SKB's assessment. Thus, SSM has used alternative stylized reference biosphere models to calculate environmental activity concentrations for use in subsequent exposure calculations. Secondly, an alternative dose model (RESRAD-BIOTA) is used to calculate doses to biota that are compared with SKB's calculations with the ERICA tool. SSM's experience from this review is that existing tools for environmental dose assessment are possible to use in order to show compliance with Swedish legislation. However, care is needed when site representative species are assessed with the aim to contrast them to generic reference organism. The alternative modelling of environmental concentrations resulted in much lower concentrations compared to SKB's results. However, SSM judges that SKB's in this part conservative approach is relevant for a screening assessment. SSM also concludes that there are big differences in dose rates calculated to different organisms depending on which tool that is used, although not systematically higher for either of them. Finally, independent regulatory modelling has proven valuable for SSM's review in gaining understanding and confidence in SKB's assessment presented in the license application.

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