[en] Non-parametric bootstrap method provides a versatile method of confidence interval calculations in case the data does not follow any known distribution or if the censoring is too high that it is difficult to fit any known distribution to the data. Therefore, bootstrap resampling techniques provides an additional method of simulation of synthetic data from existing experimental records. This helps to quantify the uncertainty and variability

[en] The basic objective of an environmental impact assessment (EIA) is to build guidelines to reduce the associated risk or mitigate the consequences of the reactor accident at its source to prevent deterministic health effects, to reduce the risk of stochastic health effects (eg. cancer and severe hereditary effects) as much as reasonable achievable by implementing protective actions in accordance with IAEA guidance (IAEA Safety Series No. 115, 1996). The measure of exposure being the basic tool to take any appropriate decisions related to risk reduction, EIA is traditionally expressed in terms of radiation exposure to the member of the public. However, models used to estimate the exposure received by the member of the public are governed by parameters some of which are deterministic with relative uncertainty and some of which are stochastic as well as imprecise (insufficient knowledge). In an admixture environment of this type, it is essential to assess the uncertainty of a model to estimate the bounds of the exposure to the public to invoke a decision during an event of nuclear or radiological emergency. With a view to this soft computing technique such as evidence theory based assessment of model parameters is addressed to compute the risk or exposure to the member of the public. The possible pathway of exposure to the member of the public in the aquatic food stream is the drinking of water. Accordingly, this paper presents the uncertainty analysis of exposure via uncertainty analysis of the contaminated water. Evidence theory finally addresses the uncertainty in terms of lower bound as belief measure and upper bound of exposure as plausibility measure. In this work EIA is presented using evidence theory. Data fusion technique is used to aggregate the knowledge on the uncertain information. Uncertainty of concentration and exposure is expressed as an interval of belief, plausibility

[en] Vitrification is the process for immobilizing the liquid high level waste generated from the reprocessing of the spent fuel from PHWR's in India. Vitirfication facility in a reprocessing plant contains Joule melter for liquefying the spent fuel. Since the Joule melter exists in the vitrification plant, it is important to check the shielding adequacy of the cell walls of the plant. This paper presents the results for estimation of dose rates outside the walls of various thicknesses of the plant, to meet the regulatory criteria. The methodology, in brief, involves estimation of the inventory of radioactivity in the melter, followed by calculation of the gamma dose rate at the given representative locations on the outer surface of the shield walls due to activity present in the melter

[en] Radiological safety analysis of nuclear fuel cycle facilities is carried out to ensure that the regulatory constraints are met during normal operation, anticipated operational occurrences (AOOs) and postulated accident scenarios. It involves performing theoretical calculations for demonstrating compliance with regulatory standards. (author)

[en] In vitrification facility a melter cell is designed to vitrify waste. Adequate cooling is required for vitrified waste product to maintain their temperatures within safe permissible limits due to less activity. The vitrified waste products are further transferred to Vitrified Waste Shielded Flask for transportation purpose. In this paper, a case study has been done for a shielded flask that contains 600000 Ci of activity. The canister in the shielded flask has activity, equivalent to about 6000 litres of High Level Waste of 100 Ci/l activity. Density of the vitrified waste product is 3 g/cc

[en] Radioactive beamline is required at bending magnet port at a synchrotron source to carry out investigations on radioactive samples such as postirradiation fuel pin samples etc. using XRD, XRF and XAS techniques. The beamline hutch will also have a mini radiological facility to handle and store radioactive samples. A study on the radiation shielding effectiveness for the said radiological facility and experimental hutch has been conducted for safe operation and to limit the dose within regulatory limit

[en] Uranium is found in ground and surface waters due to its natural occurrence in geological formations. One microgram (μg) of natural uranium has an activity of 0.67 pCi. The average uranium concentrations in surface, ground, and domestic water are 1, 3, and 2 pCi/l respectively. The uranium intake from water is about equal to the total from other dietary components. Although radioactivity of natural uranium is low, and is not likely to cause cancer, yet chances of cancer resulting from an exposure to a radioactive material like uranium cannot be completely ruled out. Numerous studies have reported Sarcomas (disease) in rats injected with metallic uranium in the femoral marrow and in the chest wall. This paper proposes a hybrid method for combining probability and possibility distributions in the estimation of cancer induction risk. The method is first explained, and then applied to estimate the human cancer risk due to Uranium in drinking water (taken from 15 villages of Kullu district of Himachal Pradesh). The hybrid method is a simple answer, from an intuitive viewpoint, to the problem of combining variability and partial ignorance in the estimation of risk. It simply combines random Monte Carlo sampling with fuzzy calculus. For the proposition 'Probability that Excess risk is lower than 3 x 10"-"6 per year', the study obtained a probability comprised between 0.945 (Belief value) and 1 (Plausibility value). The proposed risk level i.e. 3 x 10"-"6 per year is considered negligible by major toxicological agencies in the field such as EPA, WHO etc. The belief of 94.5 is the minimum credible probability level for the above proposition and suggests that the risk level is definitely minimal. (author)

[en] The Indian nuclear power program envisages closing of the fuel cycle. This involves reprocessing of the fuel and recovery of the valuable fuel materials and disposal of the radioactive waste generated in the process. The hulls produced during reprocessing of PHWR spent fuel, comprise the entire zircaloy structural mass present in a fuel bundle. This includes clad tubes, end-plugs, bearing pads, spacers and end plates. All these components of fuel are retained in the perforated basket suspended in the dissolver, and are disposed of as high active solid waste. The radioactivity accompanying the hulls has three components i) The activation products formed from alloying elements and impurities present in zircaloy2 ii) Undissolved fuel material carrying fission products and actinides adhering to the tube pieces iii) Acid solution adhering to the inert mass and comprising dissolved materials. This report estimates the activation products produced in a batch of PHWR hulls

[en] Various components used in reactor for filtering purpose, will become active due to entrapment of fission product and activation products. In this work a study is carried out, to show how the shielding effectiveness depends on the percentage of ¹³⁷Cs and ⁶⁰Co. Waste drums (Φ60 x 90) are considered to be filled with spent resin having contact dose rate of 8.77E-04 Gy/hr (100mR/hr)). It is assumed that drums containing waste are stored in a room of 700 x 500 cm² area and wall made of concrete. 45 drums are stored in 3 rack arrangement as shown in figure 1. Dose rates are calculated at location

[en] In this paper, we have used fuzzy transformation method, which was developed by Michael Hanss, for uncertainty quantification of risk due to tritium contaminated drinking water. It is an implementation of the extension principle that first discretizes the fuzzy numbers into α-cuts, and then again discretizes the α-cut intervals into sets of points. It is a technique where only particular levels of membership (α-level) values for uncertain parameters are used for simulation