Assessment of physicochemical and radon-attributable radiological parameters of drinking water samples of Pithoragarh district, Uttarakhand

This study evaluates the quality of drinking water samples (sample size = 52) taken from various locations of Pithoragarh district, Uttarakhand. The parameters include physiochemical properties viz. total dissolved solids (TDS in mg/L), electrical conductivity/salinity (µS/cm), pH and radiological dose attributable to radon in water (µSv/y). TDS values for the tested samples varied within the range of 18–434 mg/L with average value of 148 mg/L. Electrical conductivity and pH for these samples was measured as 36–868 µS/cm (average: 296 µS/cm) and 6.8–8.2 (average: 7.2), respectively. Radon activity concentration for these water samples was measured using scintillation-based radon monitor, immediately after sampling at the location site. Radon activity concentration was measured as 0.6–81.9 Bq/L with an average value of 17.8 Bq/L. The paper also estimates the annual effective ingestion dose (µSv/y), annual effective inhalation dose (µSv/y) and total effective dose (µSv/y) attributable to radon in drinking water samples. Spatial patterns for the observed variations have also been interpreted for the dataset obtained over the terrestrial region.

Wall Materials Effects on Sheltered Indoor Doses From an SMR Hypothetical Accident Release

Small modular reactors (SMRs) are expected as a suitable candidate to fulfill energy needs in the future. The regulation of the emergency planning zone (EPZ) has been a controversial issue. The possibility of smaller EPZs because of their small core size and passive safety functions has still under discussion. The major emergency responses to radiological incidents in the early phase are evacuation from the area and sheltering-in-place within a building. Comparison between the dose incurred during evacuation and that with sheltering-in-place is necessary to consider the proper protective actions. This study focuses on effect of wall materials on indoor doses for sheltered population from small modular reactor severe accident. The source term came from loss of coolant accident or station blackout, and the time change of air concentration and the ground deposition data was calculated with RASCAL, a software developed by NRC to provide dose projection around the plant. Then general one-story and two-story houses were set up, and 6 wall materials were selected for calculating indoor doses. Cloudshine and groundshine were calculated with Monte Carlo methods, and the shielding function of each house was evaluated by comparing the indoor dose with outdoor dose. The result will be a basis for calculating the radiological dose for sheltered cases in case of nuclear emergency for SMR, which will be valuable to have a more effective emergency planning.

Radiological Dose Assessment of the Landfill Disposal of Consumer Products Containing Naturally Occurring Radioactive Materials in South Korea

Naturally occurring radioactive materials (NORMs) are long-lived radioactive elements such as uranium, thorium, and potassium, and theirdecay products. They are abundant in natural rocks and minerals. In this study, we conducted a radiological dose assessment of the disposal of consumer products (CPs) containing NORMs at landfills and incinerators in South Korea. Household wastes were categorized as combustible and noncombustible on the basis of activity concentrations (ACs) ranging below and above 1 Bq/g, respectively. Analysis data were obtained from previous literature and the Nuclear Safety and Security Commission (NSSC) of South Korea, and statistical analysis was performed using an interval plot and 95% confidence interval of mean for each category as an input. Using RESRAD computer codes for noncombustible CPs with AC below and above 1 Bq/g, we found out that the dose rate was below and above 1 mSv/y, respectively. The RESRAD-OFFSITE results showed that the dose incurred during the study period for both ranges of AC was all below the public dose limit of 1 mSv/y. NORM and LegacY Site Assessment (NORMALYSA) code was used to validate the result of the RESRAD-ONSITE code, and the results showed that the dose was equal to and above 1 mSv/y for ACs below and above 1 Bq/g, respectively. HotSpot code was used for dose evaluation to offsite residents from incineration of combustible CPs, and the resulting dose was below 1 mSv/y. These findings can be used as a guideline for managing public exposure from landfill sites with varying ACs ranges. Therefore, the competent authority should ensure that criteria and protection measures are established for people who live within a distance of 10 km from incinerators and landfill sites that are contaminated with consumer products containing NORMs.

Assessing the impacts of scale residues from offshore oil and gas decommissioning on marine organisms

Successful decommissioning of offshore oil and gas infrastructure requires an effective and safe approach to assessing and managing chemical and radiological residues. Scale frequently accumulates on the interior surfaces of pipes and other structures and may persist long after extraction operations have ceased. Scale materials can contain a range of metal contaminants (including mercury), as well as naturally occurring radioactive materials. In newer or more accessible infrastructure, the scale is routinely removed, and becomes a waste product. The persistent nature of scale contaminants can result in a radiological dose to the organisms living on, or near an intact pipeline. Eventually, infrastructure corrosion following insitu decommissioning (abandonment) could lead to metal and radionuclide contaminants being accessible to the surrounding seafloor environment, where bioaccumulation and subsequent ecotoxicological effects from the chemical and radiological properties of the scale could occur. The paper describes a tiered approach to assess the ecological impacts of pipeline scale in order to assist operators with their plans for decommissioning offshore infrastructure, especially when considering ‘leave in place’ options.

Pressurization Analysis for Heating of a Screw Top Utility Can Loaded With Plutonium Oxide Powder by a 1273 K Fire

The documented safety analysis for the Savannah River National Laboratory (SRNL) evaluates the consequences of a postulated 1273 K fire in a glovebox. The radiological dose consequences for a pressurized release of plutonium oxide powder during such a fire depend on the maximum pressure that is attained inside the oxide storage containers. The oxide storage configuration selected for analysis is can/bag/can, comprised of oxide powder inside an 8.38 × 10−6 m3 stainless steel B vial inside 0.006 kg of polyethylene bagging inside a one-quart screw top utility can of the type commonly used to package solvents or rubber cements. To enable evaluation of the dose consequences, temperature and pressure transients have been calculated for exposure of a typical set of storage containers to the fire. The pressurization analysis credits venting to and from the B vial but does not credit venting or leakage from the can. Due to the low rate of venting from the B vial into the can gas space, the can pressure is nearly independent of the B vial pressure. Calculated maximum pressures are compared to the utility can burst pressure. In lieu of a structural analysis of the utility cans, burst pressures and leakage rates were measured using compressed nitrogen gas. The measured gauge burst pressure was 0.250 ± 0.043 MPa. The measured burst pressures are lower than the calculated maximum pressure due to fire exposure, indicating that the utility cans could burst during exposure to a 1273 K fire.