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[en] This volume deals with the proceedings of the international conference on problems and prospects for nuclear energy in developing countries. The topics covered include core areas of nuclear power development, safety aspects and nuclear waste management, human resources development and spin-offs from nuclear energy to medicine, agriculture and industry. It also highlights various power systems and their relative merits, nuclear fuel cycle, operational and environmental and safety considerations and public awareness and acceptance. Papers relevant to INIS are indexed separately

[en] India needs to develop and deploy all sources of electric power as rapidly as possible if it is to fulfill its mission of ensuring a decent standard of living for its people. Electricity generating technologies, like many other technologies, can have deleterious effects on the environment if due attention is not paid to this aspect in the development and deployment of these technologies. Issues related to environment and ecological aspects of electricity generation are receiving considerable attention not only by the scientific community but also by economists, development planners and most notably the public at large. The Indian Nuclear Society (INS) has chosen the theme Electricity Generation and the Environment for its Sixth Annual Conference held at the Bhabha Atomic Research Centre, Bombay during March 14-16, 1995 (INSAC-95). The conference dealt with environmental aspects of different modes of electricity generation with special reference to nuclear energy. Several contributed papers on the topic of relevance were presented at the conference. Papers relevant to INIS are indexed separately

[en] Gas phase counting provides a simple technique for health physics assay for tritium. Relative merits of hydrogen and acetylene as counting gases, both in ionization chambers and counters are discussed. Methods of sampling by condensate collection technique have been discussed. Psychrometric charts have been prepared for quick computation of airborne concentrations from the measurements under different atmospheric conditions. The same equipment has been used for assays of ¹⁴C. (author)

[en] Tritium is one of the environmentally significant radionuclides produced both in nature as well as man-made activities such as nuclear power production, tracer studies, consumer utilisation, strategic applications and fusion research. The inventory of tritium in the biosphere has been altered as a result of the above and this paper attempts to review the various aspects of man-made tritium, its behaviour in the environment and the collective effective dose equivalent commitment to the public due to the various operations in the nuclear industry. (author). 4 tabs., 1 fig

[en] ESR spectral analysis of γ-ray irradiated lyoluminescence (LL) phosphor powder, Tris (hydroxymethyl) aminomethane - referred to as 'Tris' showed the presence of two free radical species. It was observed that at higher exposure levels radical II with a singlet spectrum shows a higher growth compared to radical I with a three component spectrum. Radical I had been identified as RCHOH. The ESR-LL correlation studies indicate that the RCHOH radical formed in a low dose range is responsible for LL emission and the radical II either inhibits or does not have any role in the LL process. Based on the results observed, two models for the mechanism of LL in Tris have been proposed. The first LL model of Tris envisages the production of a dinegative luminol molecule and a restored Tris molecule when the LL enhancer luminol is used as the solvent. This is based on the hydrogen abstraction reaction of the RCHOH radical. The luminol dianion reacts with O₂ to produce the excited singlet state of the amninophthalate ion which gives the LL emission. The second model proposes that the oxidation of RCHOH radicals will yield organic peroxy radicals which in turn produces hydroperoxy (HO₂) radical and a superoxide anion. The HO₂ disproportionates, or reacts with the superoxide anion to give a singlet oxygen. The LL process in distilled water is probably due to the liberation of these singlet oxygen molecular pairs which are chemiluminescent. H₂O₂ which is also produced on the disproportionation of HO₂, or one of the interconversion products OH, can also oxidize the luminol molecule to give the emission. The LL saturation, and subsequent reduction at the increasing free radical concentration, are also discussed. (Author)

[en] A solid state dosimeter was developed with Tris (hydroxy methyl) amino methane which can measure the gamma doses in the range 0.1 Mega Rad (1 KGy) to 50 Mega Rad (500 KGy). This dosimeter is useful for measuring high dose envisaged in radiation processing of food, sterilization of medical products and high energy pulsed electron accelerator (LINAC). The paper describes the preparation of dosimetric grade pellets, measurements of the excitation and emission spectra and also the analysis of the emission spectrum. (author). 2 figs

[en] Tritium releases from a 40 MW(th) D₂O moderated reactor (Cirus) at Trombay and the environmental tritium concentrations (ambient air and vegetation samples) at different ground stations have been measured over a period of five years and the statistical correlation among the different sets of values were assessed. Distribution patterns proved to be gaussian in nature with identifiable skewness, caused by occasional larger release. The effect of the mean, median and the most probable values on dilution rate factors were found to be significant. The correlation among the sets of data showing tritium concentrations in release air, the ambient air and vegetation samples at different stations were found to be statistically good, and very nearly perfect. (U.K.)

[en] Derived Air Concentration (DAC)values for tritium being high ie., 8x10⁵Bq/m³(∼ 21.6 μCi/m³) the ambient moisture samples corresponding to such levels normally contain relatively high concentration in aqueous form. This provides comparatively larger currents in a single PMT/LS system even though the background due to thermionic noise is not very small. In nuclear power stations during operations and maintenance fraction of DAC or even higher orders of DAC of tritium are encountered. Additionally periodic inventory of moderator and coolant of PHWR systems are carried out wherein samples containing relatively larger concentration of tritium need to be analysed. Utilising these factors a simple single PMT/LS system has been designed for such purposes. The PMT used was EMI 9635 which has a dark current 10^-10 amps. A cocktail containing 10 ml of dioxan (or even smaller volumes) was used for tritium in aqueous form. A digital readout is also provided for convenience. Air concentration of tritium corresponding to several values and fractions of DAC are monitored and found that lowest detection limit was 0.05 DAC. The results obtained were compared with LSS coincidence system (Packard 4530) and correlation among the results was found to be satisfactory. The paper summarises the advantages and disadvantages of the method described. (author). 3 figs

[en] The variations of tritium releases from a heavy water reactor (CIRUS) and the uptake patterns by the vegetation in the vicinity were investigated. A rigorous sampling schedule was followed for a period of five years to study the statistical variation and its effects on environmental data. All the distributions were found to be gaussian in nature with identifiable skewness on the higher concentration values caused by occasional larger releases. In addition to the mean values, the median and most probable values of the tritium concentrations at release point, in ground level ambient air and the vegetation samples at different monitoring stations were determined from their cumulative and fractional frequency distributions. It was observed that in all cases the mean values were higher by a factor of 1.5 to 3 than the median and most probable values, due to the skewed nature of distribution. Hence the dilution rate factors calculated on the basis of mean values were found to be lower than those calculated with median or most probable values. The sample correlation coefficients and the population correlation coefficients determined from the sets of bivariates obtained from the environmental data, were found to be statistically significant (95 to 99%). (H.K.)