No abstract available

[en] Modern Society creates wastes material which have to be disposed off in nature without disturbing the ecological equilibrium. Hence effective waste management in all industries is a major concern today. So as to in Nuclear Power Plant. Atomic Power Station during it's operation and maintenance generates low and intermediate level liquid, solid and gaseous wastes. Their generations are controlled at source itself and given adequate and appropriate treatment before releasing to the environment. Different types of liquid wastes are treated through chemical co-precipitation, ion-exchange treatment, evaporation, filtration and dilution technique. For handling/ conditioning of solid wastes, volume reduction techniques such as incineration and baling, immobilization into cement and polymer matrix are employed. Gaseous waste is filtered through Pre-filter, HEPA filter, diluted with inactive air and released to atmosphere through more than 100 m high stack to get further atmospheric dilution. Regular monitoring shows that the annual maximum dose to the public around NPP in India is reported to be less than 1% of limit of 1 mSv/year recommended by ICRP. Three decades of experience have proved that present practices of nuclear waste management at Atomic Power Station are quite safe and effective with respect to ecological equilibrium. (author)

No abstract available

[en] Prior to 1984, the fuel performance in Indian PHWR units was quite satisfactory. Subsequently, the performance deteriorated. The refuelling strategies were improved to bring down the fuel failure rate. In parallel, actions were taken to review the fuel design, fabrication, quality control, and reactor operation. Post-irradiation examination of the failed bundles has also been carried out. This paper reviews the fuel performance, and highlights the improvements carried out in design, manufacture, quality control, and operation. 2 figs., 2 tabs

[en] The computer code FUDA (FUel Design Analysis) participated in the blind exercises organized by the IAEA CRP (Co-ordinated Research Programme) on FUMEX (Fuel Modelling at Extended Burnup). While the code prediction compared well with the experiments at Halden under various parametric and operating conditions, the fission gas release and fission gas pressure were found to be slightly over-predicted, particularly at high burnups. In view of the results of 6 FUMEX cases, the main models and submodels of the code were reviewed and necessary improvements were made. The new version of the code FUDA MOD 2 is now able to predict fuel performance parameter for burn-ups up to 50000 MWD/TeU. The validation field of the code has been extended to prediction of thorium oxide fuel performance. An analysis of local deformations at pellet interfaces and near the end caps is carried out considering the hourglassing of the pellet by finite element technique. (author). 15 refs, 1 fig

[en] The thermo-mechanical analysis of fuel bundle is done using FUDA software program to calculate the fission gas release and pin pressure. The fission gas release analysis was done for the average fuel dimensions. In addition, a parametric study was also performed by varying the different parameters within their specified tolerances. The thermal conductivity calculation in the present analysis accounts for the density changes and temperature variation. The feed back of gap conductance change due to fission gas accumulation in pellet clad gap is considered in fuel temperature calculations. The present paper discusses the inputs to the FUDA, mathematical model used in calculation of fission gas release and results of gas release from the FUDA runs for the above discussed analysis. (author)

[en] Two sodium iodide counters in coincidence and a twenty channel pulse height analyzer have been used to determine the pulse height distribution of 1.12 MeV gamma rays which are Compton scattered by the K-shell electrons of gold, lead and thorium. The angular variations of the differential cross section ratio, dsigma/sub K//dsigma/sub F/, have already been reported. The present measurements were made at 60 and 100⁰ scattering angles. At 60⁰, lead targets of 30 mg/cm² and 143 mg/cm² were used. At 100⁰, targets of gold (13 mg/cm²), lead (143 mg/cm²) and thorium (14 mg/cm²) were used. In all cases, pulse height distributions of false coincidence events were determined and subtracted from the measured distributions in order to obtain the true distributions. A broadening of the K-shell electron Compton peak has been observed. The results of these measurements are discussed

[en] For Indian 500 MWe PHWRs, 37-element fuel bundle design has been chosen. Since this is a new design, the specification calls for type-testing of the prototype bundles, to ensure that the design and manufacture satisfy requirements for wear, fretting, strength, fuelling-machine compatibility, in-pile performance, pressure drop, bundle dropping, etc. Various development test, including tests of materials, were also planned. 8 refs.,2 figs. 2 tabs

[en] Nuclear Fuel Complex (NFC), an industrial unit of the Department of Atomic Energy (DAE), Government of India manufactures and supplies fuel assemblies to the two Boiling Water Reactors (BWR) at Tarapur Atomic Power Station (TAPS 1 and 2) in India which were commissioned on turnkey collaboration with GE, USA. Each fuel assembly has 36 fuel elements arranged in 6x6 square configuration. Each fuel assembly contains UO₂ pellets of different enrichments. Several improvements have been carried out over the years in the manufacture of fuel assemblies. These changes have helped in improving the fuel performance considerably. During cycle 20, the unit 2 was operating at 506/153 MWth/MWe (95.47% of rated thermal power of 530MWth) prior to shut down for refueling outage. In core sipping was completed within two days. Five leakers were identified during in core sipping. The average leaky assembly's exposure was 16,098.4 MWD/T. The minimum value of a leaky assembly's exposure was 8,591 MWD/T. Out of five assemblies, four assemblies had seen two cycles of exposure and were due for discharge. One assembly had seen single cycle. Trend of chemistry parameters for the last four cycles were within tech spec limits. Similarly trend of physics parameters for the fuel assemblies for the last cycles were also within design/tech spec limits. There were no fuel failures in the previous cycles 18 and 19. The manufacturing and QA details of the five assemblies show no deviations from the procedures and the trends are normal and within specified limits. This paper discusses the analysis of fuel failures in detail

[en] The field of nonlinear optics in molecules and polymers offers challenging opportunities for theorists on both molecular modeling of new structures with enhanced microscopic response and manifestations of bulk effect in nonlinearity. This article presents an experimental point of view in assessing the current status of various theoretical approaches. Experimental results are presented for two model compounds together with predictions by various theoretical models to discuss issues and future opportunities. Three different types of nonlinear optical processes are discussed: (i) second order, (ii) third order, and (iii) photorefractivity