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 and assessment of 25 years of environmental radioactivity monitoring data at Tarapur (India) nuclear site.

The evaluation and assessment of monitoring data generated over a period of 1983-2007 (25 years) of a nuclear facility is presented. Time trends of particulate radioactivity, correlation between (137)Cs in discharge canal seawater and station discharged activity and correlation of (137)Cs, (60)Co, and (131)I in marine species such as sponge and Nerita (gastropod) and corresponding discharged activity are discussed. The concentration of (137)Cs and (131)I in seawater versus biota are discussed. A good correlation between (137)Cs in seawater and (137)Cs in liquid waste discharged was observed (R(2) = 0.8, p < 0.001). Similarly, correlation was good for Nerita and discharged concentration of (137)Cs, (131)I and (60)Co (R(2) = 0.55-0.73 and p < 0.001). The measurements over the years indicated that there is no accumulation of radionuclides in either the terrestrial or aquatic environments. The mean (137)Cs decreased from the pre-operational levels: 7.0-3.6 Bq kg(-1) in soil, 0.91-0.016 Bq L(-1) in milk and 0.28-0.036 Bq kg(-1) in vegetation. Similarly, the mean (90)Sr in these matrixes decreased from 3.9 to 0.26 Bq kg(-1); 0.37-0.011 Bq L(-1) and 0.34-0.022 Bq kg(-1) respectively. Cesium-137 of about 700 microBq m(-3) was measured in the air filter disks during 1986 and there was a decrease of three orders of magnitude in concentration over the 25 years. The evaluation of environmental data indicated that the radionuclide concentrations and potential impacts, in terms of effective dose to the members of public, have significantly reduced since 1969.

Assessment of radiological significance of naturally occurring radionuclides in soil and rock matrices around Kakrapar environment.

The activity and gamma-absorbed dose rate due to the naturally occurring radionuclides in the terrestrial environment such as (238)U, (232)Th and (40)K were determined in soil and rock samples collected around Kakrapar Atomic Power Plant site, using gamma-ray spectrometry. The mean concentration levels measured in Kakrapar soil from naturally occurring radioisotopes such as (238)U, (232)Th and (40)K are lower than the corresponding global average values obtained in worldwide soil. The external hazard index (H(ex)) and absorbed gamma dose rate in air outdoors is observed to be 0.04-0.18 and 3.1-14.1 nGy h(-1), respectively.

Vettath's anastamotic obturator--our experience of 269 proximal anastomoses.

BACKGROUND: Coronary artery bypass grafting (CABG) has come full circle-it started as an off-pump affair, then became an on pump one and now we are trying to keep off the pump again. One of the main reasons for this has been the neurological sequelae subsequent to CABG. But neurological problems kept causing concern even in off-pump CABGs (OPCAB). Side clamping the aorta was thought to be the major factor and thus came the concept of 'no touch proximal anastomoses' onto the aorta (1). Though a variety of proximal anastamotic devices are available in the market, high cost is a matter of real concern in third world countries like India. Hence, this endeavor of ours to fabricate an anastamotic device of our own-'the Vettath's anastamotic obturator' (VAO) for proximal anastomoses of saphenous vein grafts (SVG) onto the aorta. VAO is a stainless steel rod with three grooves and a guard at the end, which sinks into the aorta, through a punch hole, cordoned off by two wide purse string sutures. METHODS: After trials on perfused animal heart models, we started using this device on humans. We have performed 269 proximal anastomoses using the VAO in 177 of our OPCAB patients in the past 1 year (till July 2003). Ninety-five of them had single top ends, 72 had 2 top ends and 10 had 3 top ends onto the aorta. We have used this on disease free islands on four patients with palpable aortic plaques. Initially all anastomoses were of the proximal first type (to ensure that the flow was adequate). Now-a-days, with confidence, distal first anastomoses are being performed. RESULTS: We had no operative mortality in this group. None of our patients needed IABP support. One patient reported back with angina, after 3 months-he was studied and his grafts were found to be patent. All patients, except three, are being followed up till date and they are leading active symptom free and event free lives. DISCUSSION: It is logical to think that avoidance of side clamp on the aorta reduces the risk of neurologic complications. Vettath's anastamotic obturator is an indigenous, cheap and reusable alternative to the other costlier devices, which serve the same purpose. Though there is a small learning curve, results are gratifying and complications are few.