Negligible radiological impact of Indian nuclear power plants on the environment and the public: Findings from a 20-year study.

Nuclear power plants, recognized for their extended operational life, minimal greenhouse gas emissions, and high-power density, are deemed as reliable energy sources. Nonetheless, concerns persist regarding the radioactive discharges from these plants and their potential impact on health and the environment. To comprehend the radiological implications of such releases, this study presents, for the first time, an analysis of radiological data from 7 Indian nuclear power plants (NPPs), collected by Indian environmental survey laboratories (ESL) over the past two decades (2000-2020). This dataset encompasses radioactivity concentrations in the atmospheric, aquatic, and terrestrial environments within a 30 km radius of each NPP, as well as the annual cumulative external gamma doses recorded by environmental thermoluminescence dosimeters (TLDs). The analysis yielded several key findings: (i) Radioactivity concentrations around the NPPs were low and comparable to values measured at other nuclear power plant sites worldwide; (ii) Tritium concentrations in receiving water bodies were <1 % of the internationally recommended limit of 10,000 Bq/l; (iii) The estimated total radiation doses to the public were at most 10 % of the stipulated regulatory dose limit of 1000 µSv and consistently decreased over the study period and (iv) Variations in doses among the NPP sites were primarily attributed to legacy technology used in specific reactors. These results indicate efficient and secure reactor operations and the minimal contribution of Indian nuclear power plants to anthropogenic doses in the country. The findings hold potential significance for reinforcing India's commitment to advancing its nuclear power program.

Evaluation of uranium content and annual ingestion dose in the surface and ground water bodies of Chittorgarh, Rajasthan, India.

Uranium, naturally occurring radionuclide is chemotoxic and nephrotoxic beyond acceptable limit. The presence of uranium beyond acceptable limit in surface and ground water, adversely affecting people's health. In the present investigation, the uranium concentration in surface and ground water of Chittorgarh, Rajasthan was studied along with the physico-chemical parameters of water (n = 87). The ground water was further sub-categorised into well water, handpump water, and borewell water. The mean uranium concentration was observed at 2.5 ± 1.9 µgL-1 and 16.5 ± 1.4 µgL-1 in the surface and ground water samples, respectively. In sub-categories of ground water, the highest uranium concentration was found in borewell water (23.3 ± 17.0 µgL-1), followed by handpump water (13.5 ± 9.1 µgL-1) and well water (6.0 ± 5.5 µgL-1). The uranium concentration was correlated significantly with the depth of the ground water table. It also correlated significantly with electrical conductivity, total dissolved solids and nitrate concentration. 100% of surface water and 88.9% of ground water samples carried uranium concentration within the acceptable limit of WHO (30 µgL-1). The annual ingestion dose was found at 3.8 µSvy-1 (for males) and 2.8 µSvy-1 (for females) in surface water and 25.4 µSvy-1 (for males) and 18.5 µSvy-1 (for females) in ground water. In the sub-categories of the ground water sample, the annual ingestion dose followed the trend in males 35.8 µSvy-1 (borewell water) > 20.7 µSvy-1 (hand pump water) > 9.2 µSvy-1 (well water) and in females 26.1 µSvy-1 (borewell water) > 15.1 µSvy-1 (hand pump water) > 6.7 µSvy-1 (well water).

Sorption behavior studies of Cs and its migration in soil samples around Visakhapatnam, India.

Meeting the requirement of high specific activity of radioisotopes and carrying out comprehensive research and development activities in the nuclear field, different nuclear facilities, including their waste disposal facilities, are going to be operational at Visakhapatnam, India. Due to environmental processes, the engineered disposal modules may lose their structural integrity and may release some radioactivity to the geo-environment. The subsequent migration of radionuclides reaching the geological environment will be governed by the distribution coefficient (Kd). Cs was chosen for the sorption study in two soil samples (soil-29 and 31) and to estimate the Kd in all the 40 soil samples through the laboratory batch method at the new campus of DAE, Visakhapatnam, India. Different soil chemical parameters like pH, organic matter, CaCO3, and cation exchange capacity were determined in 40 soil samples and their effect on Cs sorption was investigated. The effect of solution pH and initial concentration of Cs on sorption was also studied. The results show that the sorption of Cs increases with increasing pH. The Cs sorption was well explained by Freundlich and Dubinin-Radushkevich (D-R) isotherm models. Site-specific distribution coefficients (Kd) were also estimated and the values were found to vary from 75 ± 1 to 540 ± 12 L kg-1. The observed wide variation in Kd could be due to large variations in the physico-chemical properties of collected soil. The competitive ions effect study suggests that K+ has higher interference for Cs+ sorption as compared to Na+. The present study results will help assess the environmental impact due to Cs release in any unforeseen scenario and in planning effective remediation strategies.

Generation of map on natural environmental background absorbed dose rate in India.

A systematic mapping of natural absorbed dose rate was carried out to assess the existing exposure situation in India. The mammoth nationwide survey covered the entire terrestrial region of the country comprising of 45127 sampling grids (grid size 36 km2) with more than 100,000 data points. The data was processed using Geographic Information System. This study is based on established national and international approaches to provide linkage with conventional geochemical mapping of soil. Majority (93%) of the absorbed dose rate data was collected using handheld radiation survey meters and remaining were measured using environmental Thermo Luminescent Dosimeters. The mean absorbed dose rate of the entire country including several mineralized regions, was found to be 96 ± 21 nGy/h. The median, Geometric Mean and Geometric Standard Deviation values of absorbed dose rate were 94, 94 and 1.2 nGy/h, respectively. Among the High Background Radiation Areas of the country, absorbed dose rate varied from 700 to 9562 nGy/h in Karunagappally area of Kollam district, Kerala. The absorbed dose rate in the present nationwide study is comparable with the global database.

Studies on diurnal variation of atmospheric tritium concentration at a sampling location near to PHWR site in Semi-Arid Zone, India.

Tritium (3H) is one of the important long-lived radioisotopes in the gaseous effluent released from Pressurised Heavy Water Reactors (PHWR). For the first time, the studies on diurnal variation of atmospheric tritium concentration was carried out using an in-house developed automatic air moisture collection sampler at Kakrapar Gujarat site, India, where PHWRs are operational. Correlation of diurnal variation of atmospheric tritium concentration with meteorological parameters such as absolute humidity, ambient temperature and wind speed is studied and presented in this paper. Positive and significant correlation of atmospheric 3H concentration was observed with respect to the absolute humidity. Negative correlation was observed in ambient temperature and wind speed. The diurnal maximum and minimum of 3H concentration was found during 21.00-23.00 h (night) and 13.00-16.00 h (day), respectively.

SITE-SPECIFIC DRY AND WET DEPOSITION VELOCITIES USING 7BE AND MASS INTERCEPTION FACTOR FOR VARIOUS TYPES OF PLANT LEAVES AT NARORA SITE, INDIA.

Comprehensive studies were carried out during the period 2016-19 on the estimation of site-specific wet and dry deposition velocities and the mass interception factor for Narora site based on the concentrations of 7Be in air, air deposits, rain water and vegetation samples. Mean wet and dry deposition velocities for Narora site were found to be 1.64E-2 and 1.58E-3 m s-1, respectively. Mass interception factors for vegetation found to be 0.34-2.51 m2 kg-1 dry weight with a mean of 0.97 m2 kg-1 dry weight. The obtained parameters shall be used for estimation of impact due to radionuclide related to Narora Atomic Power station.

NATURALLY OCCURRING RADIONUCLIDE 40K BODY CONTENT OF KAKRAPAR GUJARAT SITE POPULATION.

An attempt was made to investigate the naturally occurring radionuclide 40K body content of the Kakrapar Gujarat Site (India) population by using whole-body counting method. The population comprises occupational workers (regular and contract personnel working at Kakrapar Atomic Power station) and students from various educational institutions. A total of 1056 subjects of different age groups and gender were monitored for 40K body content by using a Standfast-II Whole Body Counting System. The reactor released radionuclides such as 137Cs, 60Co and 131I are not detected in occupational workers of Kakrapar Atomic Power station which indicates that occupational workers are free from radioactive contamination. Based on the activity measurement, an effective dose due to 40K was estimated for different groups of the site population based on the dietary habits, sex and age. Statistical significant correlation was not observed in any of the groups. The annual effective dose due to 40K was found to be in the range of 52-243 µSv y-1 with an average of 133 ± 35 µSv y-1 for the vegetarian group (588 subjects), 60-223 µSv y-1 with an average of 136 ± 35 µSv y-1 for the non-vegetarian group (468 subjects), 52-243 µSv y-1 with an average of 134 ± 35 µSv y-1 for the male group (1007 subjects) and 67-203 µSv y-1 with an average of 128 ± 35 µSv y-1 for the female group (49 subjects), respectively. Among the four age groups of the population studied, an effective dose due to 40K is slightly higher in the age group of 20-29 (161 subjects). The annual effective dose due to 40K reported by UNSCEAR, 1982(3) is 180 µSv y-1.

An environmental gamma spectrometry system with CsI(Tl) scintillator and FPGA based MCA for open field deployment.

Inorganic scintillator-based gamma spectrometry is typically carried out under laboratory conditions by using systems that require AC mains supply and dedicated computers for their operation. In this study, an in-house grown CsI(Tl) single crystal scintillator is optically coupled to a bialkali photomultiplier tube (PMT). The output of the PMT is fed to a pulse processing chain consisting of a preamplifier followed by an in-house designed and developed field programmable gate array (FPGA) based multichannel analyzer (MCA). Spectral data from this MCA is sent via serial communication to a microcontroller. A global system for mobile communications (GSM) modem transmits this data in the form of short message service (SMS) packets to a central receiving station, where the spectrum is reconstructed. The requirement of on-site data logging computer to store large spectral data has thereby been eliminated, which, in turn, has eliminated the requirement of AC power supply, reduced the overall power consumption and size of the system, and made it possible to develop a standalone solar-powered unit. For further reduction of overall power consumption, the spectrometer is turned-on only when a Geiger Mueller (GM) counter based gross gamma detection circuit, also included in the system, detects an ambient gamma dose rate beyond a pre-set threshold level. A mathematical methodology has also been implemented for restoration of recorded spectra, shifted due to temperature variations in the environment. All these features have been integrated and a standalone, solar-powered and battery operated field-deployable environmental gamma spectrometry system (EGSS) has been developed and tested for open field deployment. Presence of 41Ar in ambient air was successfully detected by the system.

Impact of oral diseases on daily activities among 12- to 15-year-old institutionalized orphan and non-orphan children in Bengaluru city: A cross-sectional analytical study.

BACKGROUND AND OBJECTIVE: As parents are the primary decision-makers of child's health, a study was conducted to assess and compare the oral health status and impact of oral diseases on daily activities among 12- to 15-year-old institutionalized orphan and non-orphan children in Bengaluru city. MATERIALS AND METHODS: This cross-sectional analytical study was conducted among 210 orphans and 210 government school children living with parents. Data with regard to the impact of oral diseases on daily activities were collected by means of Child Oral Impacts on Daily Performances (C-OIDP) index, and oral health status was determined using WHO Oral Health Assessment Form 1997. STATISTICAL ANALYSIS: Descriptive statistics of the key variables were reported and data were analyzed using Pearson's Chi-square test, Mann-Whitney U-test, One-way analysis of variance and Step-wise multiple linear regression analysis. Statistical significance was set at P < 0.05 for this study. RESULTS: Common oral health problems perceived by orphans and non-orphans were bleeding gums (16.8% and 12.4%) and toothache (12.7% and 13.7%), respectively. The daily performances most affected were cleaning mouth (33.3%; orphans 5.35 ± 4.22; non-orphans 7.05 ± 7.55; P = 0.000) and eating (33.1%; orphans 6.91 ± 6.09; non-orphans 7.07 ± 6.78; P = 0.003). Oral mucosal condition, dental fluorosis, dentofacial anomalies, and calculus showed significant difference among orphans and non-orphans (P = 0.000). CONCLUSION: C-OIDP score was high in orphans. Age, dental fluorosis, and decayed teeth were the significant factors for determining C-OIDP score. More than half of the study subjects were suffering from oral diseases which required treatment to improve their quality of life.

Knowledge, attitude, and practice of needle stick and sharps injuries among dental professionals of Bangalore, India.

BACKGROUND: A needle stick injury (NSI) is an accidental skin-penetrating stab wound from a hollow-bore needle containing another person's blood or body fluid. Healthcare workers (HCWs) including dental professionals are at an occupational risk of exposure to blood-borne pathogens following NSIs and sharps injuries (SIs). A thorough understanding of the safe practices while handling needles and sharps is crucial for HCWs to create a risk-free work place environment. AIMS AND OBJECTIVES: To assess the knowledge, attitude, practice, and prevalence of NSIs and SIs among dental professionals in a dental college at Bangalore. MATERIALS AND METHODS: A cross-sectional survey was conducted in September 2012 using a structured, pretested, guided interview-based questionnaire that was administered to 200 dental professionals in a dental college at Bangalore to assess the knowledge, attitude, practices, and self-report information of NSIs. RESULTS: In the present study, 81.5% of dental professionals were vaccinated against hepatitis B. A total of 27.5% participants had an NSI during the previous 12 months. About 41.80% of NSIs occurred during device recapping. Most common reason for failure to report the incidents of NSIs, as declared by 29.09% of the participants, included the fear of being blamed or getting into trouble for having an NSI. CONCLUSION: The knowledge of dental professionals on NSIs and their preventive measures are inadequate; however, training on Universal Precaution Guidelines, protocols regarding post-exposure prophylaxis, and safety devices has to be provided to prevent such injuries in future among the dental professionals.

Knowledge, attitude and behavioral determinants of tobacco use among 13-15 year old school children.

BACKGROUND: The epidemic of tobacco use is one of the greatest threats to global health today. Tobacco attributable deaths in India currently range from 800,000 to 900,000 per year. Adolescents are among the most vulnerable group to start tobacco use. Information on tobacco use among the youth is necessary to establish control measures against it. OBJECTIVES: To assess the knowledge, attitude, and behavioral determinants of tobacco use among high school students (age13-15 years) in Bangalore. MATERIALS AND METHOD: A cross-sectional study was conducted over a period of 3 weeks in the month of September 2012. A structured, pretested questionnaire was administered randomly to 500 high school students in Bangalore to assess the knowledge, attitude, and behavioral determinants of tobacco use. RESULTS: Majority of the study population [94.4% (472/500)] believed that smoking is definitely harmful to our health. Also, 39.0% of the participants of age 13 years believed that smoking does not help in socializing and 92.2% of study subjects had negative attitude toward starting the habit. Most of them (83.9%) had a negative perception about smokers that they lack confidence. However, less than 1% of the study population had a habit of smoking at this young age. CONCLUSION: Awareness of the harmful effects of smoking was high among the study population. The study provides insight into the factors to consider while planning adolescent anti-smoking programs in this and similar settings.

Corrosion resistance of surface modified nickel titanium archwires.

OBJECTIVE: To compare the corrosion behavior of commercially available surface modified nickel titanium (NiTi) arch wires with respect to a conventional NiTi and to evaluate its association with surface characteristics. MATERIALS AND METHODS: Five types of surface modified arch wires and a conventional NiTi arch wire, all from different manufacturers, were evaluated for their corrosion resistance from breakdown potential in an anodic polarization scan in Ringer's solution. Surface characteristics were determined from scanning electron microscopy, atomic force microscopy, and energy dispersive analysis. One-way analysis of variance and post hoc Duncan's multiple range tests were used to evaluate statistical significance. RESULTS: Surface modified NiTi wires showed significant improvement in corrosion resistance and reduction in surface roughness values. Breakdown potentials increased in the order of group 6 (conventional; 204 mV) < group 1 (nitride; 333 mV) < group 5 (epoxy resin; 346mV) < group 3 (oxide; 523 mV) < group 2 (gold; 872 mV) < group 4 (Teflon; 1181 mV), but root mean square (RMS) roughness values, which indicated surface roughness, followed a different pattern: group 3 (oxide; 74.12 nm) < group 1 (nitride; 221.651 nm) < group 4 (Teflon; 278.523 nm) < group 2 (gold; 317.894 nm) < group 5 (epoxy resin; 344.236 nm) < group 6 (conventional; 578.555 nm). CONCLUSIONS: Surface modification of NiTi wires proved to be effective in improving its corrosion resistance and decreasing surface roughness. However, neither factor could maintain a direct, one-to-one relationship. It meant that the type and nature of coating material can effectively influence the anticorrosive features of NiTi wires, compared with its surface roughness values.

Comparison study and thoron interference test of different radon monitors.

A comparison study and thoron interference test for different continuous radon monitors were carried out. The comparison study includes three passive diffusion monitors [one pulse ionisation chamber based-Alpha Guard and two silicon semi-conductor based-Radon Scout Plus (RSP)] and one silicon semi-conductor-based active radon thoron discriminating monitor--RAD 7. Radon emanation standard, supplied by National Institute of Science and Technology, has been utilised for the comparison study to qualify the calibration of the continuous radon monitors. All the instruments showed good agreement with the estimated radon concentration using (226)Ra/(222)Rn emanation standard. It was found that the active radon monitoring system is having a higher initial response towards the transient radon concentration than the passive radon monitors studied. The instruments measuring radon concentration without energy discrimination are likely to have some sensitivity towards the thoron concentration. Thus, thoron interference study was carried out in the above monitors. Nine percent interference in measured radon concentration in the Alpha Guard monitor and 4 % interference in the semi-conductor-based RSP monitors was observed. Study indicates that the interference of thoron in radon monitors depends on the area of diffusion of gas, volume of detection and sensitivity factor.

Estimation of thoron concentration using scintillation cell.

Two counting techniques are proposed in this paper to estimate thoron ((220)Rn) concentration using a Lucas scintillation cell. The alpha activity build-up inside the cell is calculated theoretically by using Bateman equations. The first method is having a minimum detection limit of 325 Bq m(-3) and can be used for thoron measurement in thorium-processing plants. In the second method, thoron concentration is calculated using the alpha counts from thoron progenies and is a reference to the first method. The results obtained by these techniques compare well with the double filter method.