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Participation in proficiency tests is an essential part of quality assurance activities for any laboratory involved in radiation metrology. Radioanalytical laboratory, Health Physics Division, BARC, regularly participates in national and international proficiency tests to demonstrate its radiometric capabilities for estimation of low-level natural and anthropogenic radionuclides in environmental matrices. The laboratory has been participating in annual IAEA Proficiency Tests conducted by Terrestrial Environmental Laboratory (TEL), IAEA, for estimation of natural radionuclides as well as fission and activation products in natural and spiked samples. This paper presents the results of estimation of ¹³⁴Cs and ¹³⁷Cs (two most important anthropogenic radionuclides that may be released from nuclear reactors during accident conditions) in spiked water samples in last five years of IAEA Proficiency Tests during 2018–2022. All results were lying well within 1σ level of the target values indicating the excellent analytical capability of this laboratory for analysis of ¹³⁴Cs and ¹³⁷Cs in aquatic environment.

Underground uranium mines, in particular, is associated with radiological conditions normally not anticipated in other mining industries. Depending on the grade and characteristics of the uranium deposit, the radiological hazard considerations may widely vary. Although short lived radon progeny are the major contributor of individual dose to the miners, dose assessment using their activity concentration data is normally avoided. Mine dust, diesel fumes, high humidity and seepage from the surrounding surface poses additional difficulty in direct estimation of radon progeny activity concentration. Individual doses are computed through radon (²²²Rn) monitoring data and equilibrium ratio (F) between radon and its short lived progeny. Both ambient and passive techniques are used in Indian uranium mines for the dose assessment but the passive technique is preferred over the ambient as the later can explicitly account the individual worker during its uses. The device, Personal Radon Dosimeter (PRD), based on nuclear track registry on a LR-115 Kotak film has indigenously been designed after detailed scientific studies. Basic features of this device, their uses, track registry and calibration aspects along with dose assessment methodology of uranium miners are provided in the paper.

This paper discusses the natural radioactivity levels in ilmenite ore and its final product. Two economically viable ores of titanium are ilmenite (FeO.TiO₂) and rutile (TiO₂). High-purity germanium (HPGe) detector was used to analyse samples of raw ore, its purified fraction and the final product (synthetic rutile). Radioactivity levels due to ²³⁸U and ²³²Th and its daughter products were estimated. The concentration of ²³⁸U and ²³²Th in raw ore, purified ore and synthetic rutile was found to be 204 ± 4 and 1208 ± 5, 89.0 ± 4 and 597.0 ± 4, 119 ± 2.5 and 398.0 ± 3 Bq/kg, respectively. The dose rates due to gamma photons estimated in raw ore and synthetic rutile were 572 nSv/h and 277 nSv/h, respectively. The activity index estimated was 5.3 for raw ore and 2.3 for final product (synthetic rutile). The final product contained only 25% of the radioactivity compared to the ore showing significant reduction in radioactivity due to the processing of the ore.

A study on natural radioactivity in soil around Tummalapalle uranium mineralised region was carried out. The aim of this study was to find the activity of primordial radionuclides ²²⁶Ra, ²³²Th and ⁴⁰ K over the span of 5 years from 2018 to 2022 to understand the trend of activity of radionuclides in soil and impact of mining activities on the surrounding soil. The overall average activity of ²²⁶Ra, ²³²Th and ⁴⁰ K over the years has been found to be 25 Bq/kg, 40 Bq/kg and 478 Bq/kg, respectively. The ²²⁶Ra and ²³²Th activities have been found to be less, whereas ⁴⁰ K activity has been found to be slightly higher than the worldwide average of 32, 45 and 412 Bq/kg. The activity of radionuclides over the years does not show any increasing trend, which indicates that there is no impact of mining activities in the region on the soil in surrounding environment. Radium equivalent for soils was found to be 117.10 Bqkg⁻¹, which is lower than the recommended limit of 370 Bqkg⁻¹, and the annual effective external dose was found to be 345.56 µSvy⁻¹, which is less than the worldwide average of 460 µSvy⁻¹. External hazard index was found to be 0.35 Bq kg⁻¹, which indicates insignificant radiation hazard from natural radionuclides in soil.

The eastern coast of India, particularly near the Rushikulya River Bay, has several industries, port and urban settlements, which makes it important to study the dissolved radon concentration in the groundwater as well as in the seawater of this area. In the present study, 20 samples (9 groundwater and 11 seawater samples) were analysed using the AlphaGUARD radon monitor for the naturally occurring ²²²Rn. The study reveals that radon concentration in the groundwater is higher, which varies between 631 and 3142 Bq m⁻³ in comparison with the radon concentration in coastal waters that have a range between 160 and 289 Bq m⁻³. The difference in the concentration of radon in the shallow groundwater and the seawater shows that proper accounting for radon in the system will lead to quantification of the submarine groundwater discharge in this coastal region.

Xenon (Xe) is a noble gas and therefore chemically inert in the environment. The Earth’s atmosphere contains approximately 0.087 ppm of stable xenon. Radio xenon isotopes like ¹³³Xe and ¹³⁵Xe are artificial isotopes generated from various nuclear facilities. Atmospheric measurement of radioactive xenon isotopes (radio xenon) plays a key role in remote monitoring of any nuclear accidents, abnormal release from nuclear facilities or nuclear explosions, since radio xenon has a high capability to migrate in a wide range from the site. The measurement of these gamma-emitting radioxenon gas can be done by sampling the gas in measurement geometry (like gas cell) and counting the cell in suitable gamma spectrometry-based detector system. For measurement of radioactive content in the sample, the efficiency calibration of system has to be carried out with same measurement geometry and same gamma ray energy that of sample. Many times, the radioactive standard sources in same measurement geometries and for same gamma energies are not feasible. In such cases, experimentally validated computational techniques are used for generating efficiency function. This paper describes the application of computational technique for measurement of radio xenon (¹³³Xe and ¹³⁵Xe) gas in the environment.

In view of the dispersible nature of the radiologically significant gaseous radon (²²²Rn) and its dependence on metrological variables, an investigation was carried out in the uranium mineralized region of Jaduguda. Two distinct locations, comprising of prototype dwellings and outdoor environment outside the dwellings were chosen for the comparative study. The investigation was carried out during monsoon, autumn and winter seasons so that a profile ranging from minima to maxima can be accounted. Along with the ²²²Rn concentration profile and gamma level, the metrological variables such as ambient temperature, pressure, relative humidity has also been investigated. Results of sixty six (66) outdoor and thirty nine (39) dwellings monitoring was found to have ²²²Rn concentration ranged from 9 to 68 Bq m⁻³ and 35 to 130 Bq m⁻³, respectively, in outdoor and indoor with corresponding average value of ²²²Rn concentration were found 34 ± 13 and 79 ± 24 Bq m⁻³, respectively. These values are well within the expected range of a uranium mineralized area. Also, the outdoor ²²²Rn activity concentration is about 43% of the indoor ²²²Rn activity concentration, which can be attributed to greater atmospheric dilution and related metrological variables like higher temperature.

Measurements of atmospheric release from underground uranium mine at Narwapahar in state of Jharkhand has been done to assess the discharged ²²²Rn at surface from ventilation shafts of mine. Annual volume of atmospheric discharge has been estimated around 6 × 10⁹ m³ from ventilation shafts of mine with associated radon (²²²Rn) activity around 2.3 × 10¹³ Becquerel. Such a huge amount of radioactivity discharge in open atmosphere through underground uranium mine is always under consideration to assess the exposure of public residing in surrounding villages, if any. Realizing the non-negligible health hazards due to radon exposure, the present study has been carried out to measure the radon concentrations in surface discharged air. A portable radon-measuring device (Alpha-guard) is used to determine the radon levels. Alpha-guard is used in diffusion mode for the measurements of radon concentration in the vicinity of ventilation shafts of the U-mine. The study reveals that the discharge of radon from mine exhaust is confined within 100 m of the discharge point of the mine (in no man area within mine premises) and it does not affect the inhalation hazards to inhabitants residing in public domain in nearby villages.