Total Effective Dose Equivalent Research Articles

Assessment of radiological consequences to a hypothetical accident of the 3-MW TRIGA Mark-II nuclear research reactor of Bangladesh

The radiological consequences to a hypothetical accident are assessed for the 3-MW TRIGA Mark-II Nuclear Research Reactor of Bangladesh for both wet and dry seasons. Accident simulations are crucial for assessing the potentialrisks in the event of a nuclear accident. ORIGEN code was used to carry out the facility's radionuclide inventory. In the event of a hypothetical accident, the Total Effective Dose Equivalent (TEDE) is assessed using HotSpots. The findings indicate that for stability class A during the rainy season, the selected radionuclides arrived at a downwind distance of 0.03 km with an arrival time of less than one minute, and the highest TEDE, respiratory time-integrated air concentration, and ground deposition activity, respectively, were marked at 2.8E-12 Sv, 9.4E-01 Bq-sec/m3, and 2.4E-05 kBq/m2. In the case of I-131 at 0.03 km from the source, the thyroid gland is the most sensitive human organ, followed by the lung, esophagus, thymus, surface bone, skin, and breast. The estimated Committed Effective Dose Equivalent (CEDE) from I-131 is 9.1E-11 Sv. In contrast, the adrenal was the most sensitive organ with a maximum CEDE of 1.3E-13 Sv in the case of Cs-137 at a downwind distance of 0.03 km. The highest TEDE values for the general public and the vicinity around the TRIGA Mark II reactor facility are lower than the annual dose limits.

Radiological environmental impact analysis of the uranium mining site in Mika, Nigeria using time series forecast model.

This study employs time series forecasting, specifically Seasonal Auto-Regressive Integrated Moving Average, to predict the radiological impact of uranium mining in Mika, Nigeria. By utilizing meteorological data to model the dispersion of radioactive emissions to receptors, allowing for a comprehensive assessment of potential health and environmental consequences. The study observed a slight change in the Total Effective Dose Equivalent (TEDE) at the nearest residence northeast receptor between the actual and the forecasted data. The findings could be largely because of the basement complex rock formations that characterized the Mika region. The study recommend proper monitoring and evaluation should be done before full-scale mining can be carried out. However, the TEDE is generally below the International Atomic Energy Agency recommended level of 1mSv per y for public exposure. The research demonstrates the significance of predictive modeling in managing and mitigating the radiological risks associated with uranium mining activities. Findings contribute to informed decision-making and sustainable resource extraction practices in Mika, Nigeria.

Application of uncertainty and sensitivity analysis in dose assessment during a postulated LBLOCA for VVER-1000 nuclear reactor

A key element in the process of accident analysis for the event of a severe nuclear emergency such as the large break loss of coolant accident (LBLOCA) is to properly quantify safety margins using reliable tools. Assessing the consequences of radioactive material release and the equivalant dose after the LBLOCA can provide clarity about the accident. Reliable safety analysis methods for nuclear power plants (NPPs) can be used to obtain relatively realistic outcomes considering the complex uncertainties of NPP events. In this study, an appropriate technique for sensitivity and uncertainty analysis is employed to develop a methodology for performing dose assessment within a postulated LBLOCA including uncertainties. Considering the approved reliability over the years and safety aspects, VVER reactor is among the most widely used nuclear reactors, which is selected as the case study in this article. The main problem that the study aims to solve is to illustrate whether the inordinate deviation of the input parameters from their reference values lead to violation of the allowed TEDE value by conducting uncertainty analysis. For performing calculations of total effective dose equivalent (TEDE), the environmental contamination with radioactive materials has been simulated using HotSpot code and the obtained results were compared with the solutions of JRODOS program. To obtain the most influential parameters on the obtained TEDE values in different distances from the NPP, an appropriate sensitivity analysis has been carried out, following which the Wilks’ statistical method is used to generate 59 data samples with uncertainty propagation and 95 % confidence. The resulting uncertainty bands demonstrate that the maximum TEDE values of calculated data lie within about 7 to 15 mSv in the postulated LBLOCA scenario, which are below the threshold limit of 50 mSv recommended by International Atomic Energy Agency.

Enhancing Resilience through Nuclear Emergency Preparedness at El Dabaa Site

The research utilized advanced PCTRAN and RASCAL software to evaluate the potential radiological impacts of hypothetical accidents, specifically loss-of-coolant accident (LOCA) and long-term station blackout (LTSBO), at the El Dabaa Nuclear Power Plant. Over a span of ten years, comprehensive meteorological data were meticulously analyzed to assess the dispersion of radioactive substances within a 40-kilometer radius across all four seasons. The outcomes revealed that only in the case of LTSBO did the radiological levels surpass the limits set by the Environmental Protection Agency (EPA). Notably, during spring, LTSBO exhibited a maximum total effective dose equivalent (TEDE) value of 13 millisieverts (mSv) at a distance of 3.2 kilometers, and the highest thyroid dose (TD) recorded was 63 mSv at 8 kilometers. These significant findings play a crucial role in shaping strategies related to the distribution of potassium iodide (KI) and further enhance the overall preparedness and evacuation planning protocols.

Radiological Risk Assessment of Soil Using RESRAD-OFFSITE Code in Communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria

Anthropogenic activities around a fertilizer company can cause elevation in the concentration of naturally-occurring radioactive materials (NORMs) within surrounding soils, as a result of effluent discharge or heaping of rocks used as raw materials. The aim of this study was to evaluate the human risk associated with exposure to NORMs in soils from communities around Indorama Fertilizer Company Eleme, Port-Harcourt, Rivers State, Nigeria. A sodium-iodide doped with thallium [NaI(TI)] detector was used to measure activity concentrations of these NORMs in 22 soil samples within the study area. The residual radioactivity (RESRAD) offsite modeling program(version 4.0) was then used to estimate the radiation doses and the cancer morbidity risk of uranium-238 (238U), thorium-232 (232Th) and potassium-40 (40K) for hypothetical resident farmer scenario. According to the RESRAD prediction, the maximum total effective dose equivalent (TEDE) during 100 years was found to be 2.82 x 10-5 mSvy-1 at year 12, while the maximum total excess cancer morbidity risk for all the pathways was 3.52E-08 at year 6. Therefore, results obtained from the RESRAD-OFFSITE code in this study has shown that the health risk from effluent discharge within the study area is within acceptable levels according to international standards.

Consequence assessment of hypothetical urban radiological dispersal device incident in Korea

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.

Analysis of nuclear accident scenarios and emergency planning zones for a proposed Advanced Power Reactor 1400 (APR1400)

Radiological scenario analysis considering potential accidents and the corresponding emergency planning arrangements are based on the estimations of radioactive releases following such accidents. This involves investigating the possible effects on the surrounding population and environment. The current paper hypothesized three accident scenarios in a pressurized water reactor (PWR) proposed to be located in Khor Duweihin on the Western Coast of the Arabian Gulf. HotSpot tool was used to estimate the total effective dose equivalent (TEDE) due to certain released radionuclides of different chemical groups. Initial emergency planning arrangements were defined based on the estimated doses triggered by the hypothetical scenarios considered: loss of coolant accident (LOCA), station blackout (SBO) and steam generator tube rupture (SGTR) in an Advanced Power Reactor 1400 (APR1400). This study established a baseline for an emergency plan that assures the mitigation of radiological consequences due to probable nuclear accidents, involving preparedness based on forecasting the atmospheric dispersion of radionuclides released during potential scenarios in different meteorological conditions.

Radiological Impact Assessment for hypothetical accident scenarios of a proposed pressurized water reactor using HotSpot code

The radiological risks following two severe hypothetical accidents at a proposed pressurized water reactor (PWR) in Umm Huwayd in the Eastern Coast of Saudi Arabia, have been determined using the health physics code HotSpot 3.1.2, developed by Lawrence Livermore National Laboratory, USA. In this paper the general plume dispersion code was used, the Total Effective Dose Equivalent (TEDE) were estimated and the direction of propagation was included the two accident scenarios for various stability classes A, B, C, D, E and F. At a closer distance to the release point the TEDE peaked faster for class A in both accident scenarios. The maximum TEDE values received by the NPP site workers, member of public and the permanent resident were estimated for both accident scenarios at a distance of 0.12 km, 4 km and 80 km from the released source point, respectively. For the two accident scenarios at two distances (0.10 km and 80 km) from the release point, the TEDE values were evaluated for different pathways (inhalation, submersion, ground shine and resuspension). The outcomes showed that for both scenarios, at 0,10 km, the submersion pathway is the dominant intake followed by inhalation and at 80 km distance, the most dominant pathway was found to be (inhalation) followed by (submersion). The effective release height of 10 m, 20, 30 m and 40 m was simulated and found to have inverse relation with TEDE and the ground deposition. Inversion layer height also was evaluated.

Prediction of radioactivity releases for a Long-Term Station Blackout event in the VVER-1200 nuclear reactor of Bangladesh

Consequences of an anticipated Beyond Design Basis Accident (BDBA) Long-Term Station Blackout (LTSBO) event with complete loss of grid power in the VVER-1200 reactor of Rooppur Nuclear Power Plant (NPP) of Unit-1 are assessed using the RASCAL 4.3 code. This study estimated the released radionuclides, received public radiological dose, and ground surface concentration considering 3 accident scenarios of International Nuclear and Radiological Event Scale (INES) level 7 and two meteorological conditions. Atmospheric transport, dispersion, and deposition processes of released radionuclides are simulated using a straight-line trajectory Gaussian plume model for short distances and a Gaussian puff model for long distances. Total Effective Dose Equivalent (TEDE) to the public within 40 km and radionuclides contribution for three-dose pathways of inhalation, cloudshine, and groundshine owing to airborne releases are evaluated considering with and without passive safety Emergency Core Cooling System (ECCS) in dry (winter) and wet (monsoon) seasons. Source term and their release rates are varied with the functional duration of passive safety ECCS. In three accident scenarios, the TEDE of 10 mSv and above are confined to 8 km and 2 km for the wet and dry seasons, respectively in the downwind direction. The groundshine dose is the most dominating in the wet season while the inhalation dose is in the dry season. Total received doses and surface concentration in the wet season near the plant are higher than those in the dry season due to the deposition effect of rain on the radioactive substances.

Evaluation of Patient Transmission Factor Following the Administration of 177Lu-DOTATATE.

177Lu-DOTATATE is a radionuclide therapy that is FDA approved for the treatment of somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors. Treatment facilities are required to determine the maximum radiation dose from such subjects to the maximally exposed member of the public, ensuring that the total effective dose equivalent (TEDE) does not exceed regulatory limits. If the calculated TEDE meets the regulatory limits, the patient is eligible for release and provided instructions with radiation precautions. This study aims to determine a mean transmission factor to the patient to improve accuracy and individualize the estimation of the TEDE.

Estimation of public exposure during normal operation of unit-1 Barakah Nuclear Power Plant using GALE and HOTSPOT

In August 2020, the first Barakah Nuclear Power Plant (BNPP) unit was connected to the grid and started supplying electricity. The BNPP site consists of 4 pressurized water reactor units, and each unit generates electricity up to 1400 MWe power. Concerning safety, the radiological assessment of the radioactive release and the corresponding public exposure during normal operation is essential. In the present work, the radioactive release during normal operation, in gaseous form, is calculated considering the operating condition of the BNPP by using the GALE code for gaseous forms. Then, the HOTSPOT code is used to simulate the radiological dispersion, including the public exposure and Total Effective Dose Equivalent (TEDE). HOTSPOT code uses the Gaussian dispersion model to provide near-surface releases, short-range dispersion, and short-term releases. Finally, the results in the present work are compared with the values given in the Final Safety Analysis Report of the BNPP. For typical operating circumstances, this study evaluated gaseous source terms such as iodine, noble gases, radioactive particles, tritium, C-14, and Ar-41 and found that TEDE values are within the authorized limits for distances up to 80 kms from the power plant.

Coupling of ASTEC V2.1 and RASCAL 4.3 Codes to Evaluate the Source Term and the Radiological Consequences of a Loss-of-Cooling Accident at a Spent Fuel Pool

Abstract This paper deals with a general methodology to evaluate the Source Term (ST) and the Radiological Consequences (RC) of a hypothetical Severe Accident (SA) at a Fukushima-like Spent Fuel Pool (SFP) by coupling ASTEC 2.1 and RASCAL 4.3 SA and consequence projections (CP) codes, respectively. The methodology consists of the following sequential steps: the ST provided by a prior simulation performed by ASTEC V2.1 code was used as input to RASCAL 4.3 code to make a RC analysis. This approach was developed as a preparatory study for the Management and Uncertainties in Severe Accident (MUSA) H2020 European Project, coordinated by CIEMAT, where the ENEA's Nuclear Installations safety laboratory is committed to performing an analysis on a Fukushima-like SFP with the aim to apply innovative management of SFP accidents (WP6) to mitigate the RC of the accident itself. To perform the RC studies that could have an impact on Italy, a Fukushima-like SFP was assumed located in one of the Italian cross-border NPP sites. The weather data adopted are both standard and real hourly meteorological data taken from more than one geographical location. The results of the RC for 96 h of ST release in a range of 160 km from the emission point are reported in terms of Total Effective Dose Equivalent (TEDE), Thyroid dose, and Cs-137 total ground deposition. The mitigating effect on ST and on RC of the cooling spray system (CSS) actuated with several pH values (i.e., 4,7,10) was also investigated.

Radiological modeling of the impacts of the Chernobyl nuclear power plant accident on Turkey and southwest Asia

Many studies investigated the impacts of the Chernobyl Nuclear Power Plant accident on Europe. However, majority of these have spatially excluded the highly populated southeast region of Chernobyl, including countries such as Turkey, Armenia, Georgia and Iran. In this study, a comprehensive environmental and radiological analysis were conducted particularly for this region. For this purpose, atmospheric dispersion and ground deposition of radionuclides were estimated using a Lagrangian particle dispersion model, FLEXPART. Totally, six simulations were conducted and model results were validated with measurements from Europe and Turkey. Furthermore, total effective dose equivalent (TEDE) values were estimated for adults and infants using the most current dose conversion factors of ICRP. Highest deposition of 137Cs were found in around Eastern Black Sea areas (10–40 kBq/m2). Similar values were found in some locations of Armenia and Azerbaijan under some scenarios, but country averages of 137Cs deposition were lower than 10 kBq/m2 for both countries. No significant depositions were found in southwest Iran, but relatively higher depositions (2–10 kBq/m2) of 137Cs were estimated along the Turkish border. Although there were slightly higher values in northern areas of Syria, Iraq, Lebanon and Cyprus, 137Cs depositions were mostly less than 2 kBq/m2. The 1-year TEDE value was calculated less than 1 mSv throughout the model domain except for some regions of eastern Black Sea. Highest values in lifetime dose values were calculated along the Black Sea coasts of Turkey and Georgia. Overall, infants were affected more from ionizing radiation compared to adults in this region.

Effect of certain metrological parameters on the extension of urgent protective action zone in Tehran research reactor accidents

In a core melting accident of a reactor, the release of radioactive material into the environment is inevitable. The amount of effective dose received by people around these facilities and consequently the urgent protective action zone (UPZ) strongly depend on the climatic conditions at the time of the accident and afterwards. In this study, the effect of wind speed, air stability class, temperature, and rainfall on the total effective dose equivalent (TEDE) at different time/place intervals of a hypothetical partial core melt accident around a research reactor was investigated using simulation method. The results showed that the stability class E, warm temperature, and light rain could lead to the highest dose of individuals. In addition, very low wind speeds were recommended for the facilities located in cities with high density of high-rise buildings and/or tropical areas in this regard.

Natural radioactivity level in fly ash samples and radiological hazard at the landfill area of the coal-fired power plant complex, Vietnam

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of 238U, 226Ra, 232Th and 40K were 93, 77, 92 and 938 Bq kg−1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y−1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30 ×10−3, 4.26 ×10−3, 0.62 ×10−3, and 25.61 ×10−3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

Radiological Dose Assessment to Members of the Public Using Consumer Products Containing Naturally Occurring Radioactive Materials in Korea.

Various products containing a small number of added radionuclides are commonly available for use worldwide. However, frequent use of such products puts the public at risk of radiation exposure. In this study, dose assessments to members of the public using consumer products containing naturally occurring radioactive materials (NORMs) were conducted for various usage scenarios to evaluate the external and internal exposure dose. Data for this study were obtained from previous literature and were statistically analyzed using Boxplot to determine the input data for assessment. A normalized value of activity concentration was used for dose evaluation. In addition to other external and internal dose calculation codes, analytical calculations were used to perform age-dependent. Based on analytical calculations, the highest total effective dose equivalent (TEDE) received from necklace products at the upper whiskers with an activity concentration of 4.21 Bq/g for 238U, 24.4 Bq/g for 232Th, and 0.55 Bq/g for 40K for various age groups is 2.03 mSv/y for 1 year old, 1.24 mSv/y for 10 years old and 1.11 mSv/y for adult, which are above the international commission for radiation protection (ICRP) recommended public dose limit of 1 mSv/y. Results of external and internal exposure dose obtained using Microshield code, IMBA code and Visual Monte Carlo (VMC) code are all below the recommended public dose limit of 1 mSv/y.

Preliminary DCGLW for surface soil of Kori Unit-1 decommissioning site according to habit data and age of human receptors

The preliminary derived concentration guideline level (DCGLW) for the surface soil of Kori Unit-1 was calculated considering the habit data of residents living near the nuclear power plant in South Korea (a 1-y-old infant, a 10-y-old child, and an adult), following the ICRP 101a recommendation for radiation protection of the public. The radionuclides of interest were 3H, 14C, 60Co, 63Ni, 90Sr, 134Cs, 137Cs, and 241Pu. 14C, 3H. 14C, 3H, and 241Pu had the maximum total effective dose equivalent (TEDE) after a certain duration, whereas 60Co, 63Ni, 134Cs, 137Cs, and 90Sr had the maximum TEDE in the first year. In the initial period, 60Co, 134Cs, 137Cs, and 90Sr had the most dominant effect on TEDE in all the age groups, but their influence disappeared after 203.09 y and only doses of 241Pu and 90Sr were observed thereafter. The main exposure pathways of 60Co, 134Cs, and 137Cs were external pathways, but the main exposure pathways of 90Sr were plant (water-independent), meat (water-independent), and milk (water-independent). The maximum TEDEs caused by 60Co, 134Cs, and 137Cs were similar in all the age groups, but that caused by 90Sr considerably varied depending on the age group. The nuclides for which the DCGLW was notably different from the conservative DCGLW were as follows: 3H (increment of 109.21% and 183.08% for the child and adult, respectively), 63Ni (increment of 286.37% and 702.86% for the child and adult, respectively). The main exposure pathways for these radionuclides were ingestion pathways (water-dependent or independent), which led to internal exposure. The findings can provide insight for the considerations of the human receptor to calculate the DCGLW for the surface soil of Kori Unit-1 using RESRAD-ONSITE.

Prediction of Potential Offsite TEDE, Excess Cancer Risk, Dominant Exposure Pathways, and Activity Concentration for Hypothetical Onsite Soil Contamination at the Proposed Rooppur Nuclear Power Plant

Abstract This study evaluates the potential offsite radiological hazards by calculating total effective dose equivalent (TEDE) and excess cancer risk if onsite soil contamination occurs at the proposed Rooppur Nuclear Power Plant (RNPP) site, Bangladesh. The assessment has been performed assuming a hypothetical soil contamination associated with Fukushima Nuclear disaster with the help of the RESRAD (residual radioactivity) OFFSITE computer program developed by Argonne National Laboratory, U.S. Six radionuclides, namely, Cs-134, Cs-136, Cs-137, La-140, Sr-90, and Te-129m have been considered. The maximum TEDE has been found approximately 2.8 mSv/yr whereas the maximum total excess cancer risk shows a value of 3.25×10−3. The number of dominant exposure pathways, maximum contributor pathways, and duration of dominance of different nuclides have been identified. Ingestion of fish is identified as the principal pathway to both TEDE and excess cancer risk. Time variation of activity concentration and dose/source ratio have also been studied.

Modeling of atmospheric dispersion and radiation dose for a hypothetical accident in radioisotope production facility

Atmospheric dispersion modeling and radiological safety analysis is performed for public outside radioisotope production facility (RPF) in case of hypothetical radioactive Iodine spilling and leakage from hot cell. Potential human error is expected and column that occupies Iodine may be broken causing it to spill on the radioactive cell floor. Ventilation exhaust system is dedicated to extract dispersed material through dedicated filters before gases expelled outside the facility. Two scenarios are performed in this paper; the first one is predicting the dispersion with good filtration from extract ventilation system, while the other is with loss efficiency of filtration components. The spilled radioiodine is the source term, and the HotSpot 3.1, Health Physics code designed by LLNL (Carestiaet al, 2016) is used to provide required calculation tool to assess and evaluate emergency situation including radioactive nuclides release to illustrate the transport modeling which is then applied to estimate the total effective dose equivalent (TEDE) in different Pasquill stability classes, and how it would be transferred to human body depending on downwind distance and radionuclide activity. The adopted methodology uses dominant site-general meteorological data and theories of dispersion models to study the impact of hypothetical dispersion and release to the environment from the selected radionuclide and assess how such dispersion may have radiological worse impact on public.

POTENTIAL ENVIRONMENTAL HAZARD TO THE PUBLIC FROM THE OPERATION OF URANIUM MINING AND MILLING FACILITY.

Mining and milling processes could cause potential radiological exposures to the public. The objective of this study was to estimate the off-site radiological doses expected to be received by the public as a result of uranium mining and milling activities at Mkuju River Project in the United Republic of Tanzania. MILDOS-AREA was used to estimate off-site doses along with RESRAD-OFFSITE for comparison and verification. Since the mining has not yet started, the conceptual scenario was chosen. Using the concept of the most exposed individual, the location of the nearest residence (receptor) was chosen at 2.5km from the site with other receptors being the fence boundary and grazing area being at 1.0 and 1.8km, respectively. Yellowcake stack (point source), ore pad and two tailing piles where each had an area of 2.5×105m2 were chosen to be the source of radiological contamination. The radiological source term was obtained from the concentration of 226Ra and 232Th in soil obtained from the previous studies of environmental impact assessments. Meteorological and site-specific data were used for this analysis. The estimated total effective dose equivalent (TEDE) for the nearest residence which was calculated by MILDOSE-AREA ranged from 2.5×10-2 to 4.45×10-2mSv/y during the operation of 13y. The result of RESRAD-OFFSITE ranged from 7.19×10-2mSv/y for the first year to 7.43×10-2mSv/y in the final year. This implied all the estimated TEDEs were below the dose limit and dose constraint of 1 and 0.3mSv/y, respectively, as suggested by the International Atomic Energy Agency. Hence, it was found that there was no potential radiological concern of uranium mining at Mkuju River Project. It was found that using MILDOS-AREA it is possible to estimate dose at different distances from the facility. Therefore, this study apart from estimating the off-site doses, it can be used for planning of public and social premises before the commencement of the project. That is the distance from the facility where the public should be located as well as other locations for social activities.