[en] DyCrO₃/r-GO (DCO/r-GO) and Dy_0.5Ho_0.5CrO₃/r-GO (DHCO/r-GO) nanocomposites consisting of 5 wt.% r- GO were synthesized by the sol–gel method, and their photocatalytic performance was studied on methylene blue (MB) and rhodamine B (RhB) dyes under solar irradiation. The bandgap energy of DCO/r-GO and DHCO/r-GO nanocomposites was found to be 2.63 eV and 2.58 eV, respectively. The DCO/r-GO and DHCO/r-GO nanocomposites demonstrated remarkably higher photocatalytic activity than DCO and DHCO nanoparticles. The DCO/r-GO and DHCO/r-GO nanocomposites furnished 69.6% and 71.6% degradation of the MB dye and 87% and 96% degradation of RhB dye within 180 min under direct sunlight. (author)

[en] Desalination is one of the reliable and viable alternatives to meet the increasing requirements of safe water both for potable and industrial uses. A number of states in India are water stressed and they have to resort to water resource augmentation measures such as rain water harvesting, water recovery and recycle from spent streams and desalination of both brackish and sea water. A number of desalination plants are already in operation in states such as Tami Nadu and Gujarat to meet the increasing demand for fresh water. Seawater desalination has now become an important means to augment the fresh water resources in the vast water scarce coastal arid and semi-arid areas worldwide. A 15-20% growth in desalting plants capacity has been reported during the last few years. Most of the operating seawater desalination plants are cogeneration plants producing both power and fresh water and by and large these use fossil fuels as energy source. Due to serious environmental concerns of the green house gas emissions from large size power-desalination plants based on fossil fuels, a number of countries have kept the decision to launch mega desalination projects, which are required to alleviate the water shortages, in abeyance. Bhabha Atomic Research Centre (BARC) Trombay has been one of the pioneers in the development of desalination technology involving both the membrane and thermal processes. The approach is to couple Nuclear Power Plant with Multi-stage flash (MSF) hybridized with Reverse Osmosis (RO)

[en] A hybrid desalination plant consisting of 1800M³ /day Seawater Reverse Osmosis (SWRO) and 4500 M³ /day multi-stage flash distillation (MSF) units, is being set up at Kalpakkam, adjoining Madras Atomic Power Station (MAPS). The construction of both these units of plant has thrown many challenges imposing severe constraints as they are being retrofitted to the existing power plant. The steam supply system and sea water intake system required unique approach, both in erection and commissioning. MSF evaporator modules involves quality and precise fabrication of thousands of tonnes of carbon steel, stainless steel and cupronickel put together. This being the first desalination plant of its kind in the country, had to overcome numerous obstacles and face surprises and peculiar problems. In spite of this SWRO unit is in operation since Oct-2002 and for MSF unit brine heater, brine circulation pumps, holdup tank, isolation heat exchangers are completed and evaporator module construction is going in full swing and is likely to go on stream in near future. This paper attempts to describe the problems encountered during erection, commissioning and operation of the NDDP plant at Kalpakkam. (author)

[en] Highlights: • Dry and wet (MWDD) methods were developed for 100% recycling of CRO (0.4–44% PuO₂). • Dry method showed higher productivity and comparable powder/product characteristics. • MWDD batches demonstrated improved powder/product characteristics to that of virgin. • Second/multiple recycling is possible with MWDD with better powder/product characteristics. • MWDD batches prepared by little milling showed better macroscopic homogeneity to that of virgin. - Abstract: The dry and wet recycling processes have been developed for 100% recycling of Clean Reject Oxide (CRO) generated during the fabrication of MOX fuel, as CRO contains significant amount of plutonium. Plutonium being strategic material need to be circumvented from its proliferation issues related to its storage for long period. It was difficult to recycle CRO containing higher Pu content even with multiple oxidation and reduction steps. The mechanical recycling comprising of jaw crushing and sieving has been coupled with thermal pulverization for recycling CRO with higher Pu content in dry recycling technique. In wet recycling, MicroWave Direct Denitration (MWDD) technique has been developed for 100% recycling of CRO. The powder prepared by dry and wet (MWDD) recycling techniques was characterized by XRD and BET techniques and their effects on the pellets were evaluated. (U,21%Pu)O₂ pellets fabricated from virgin powder and MWDD were characterized using optical microscopy and α-autoradiography and the results obtained were compared

[en] Austenitic stainless steel AISI 310S is used as the material of construction for Reduction retorts. SS 310S is selected for its ease of fabrication, corrosion and elevated temperature (around 850ÚC) properties. Matching welding consumables (E 310/ER 310) are used for welding of longitudinal and circumferential joints during fabrication of these retorts. The high temperatures applied during both welding and service, significantly affect the microstructure and properties of the weldment. During operation, these retorts are subjected to highly corrosive chloride environment in addition to high temperature. The middle zone operating temperature is 600ÚC to 700Ú C and undergoes inter granular stress corrosion attack (IGSCC) from inside and oxidation on outside surface. The bottom zone operating temperature is 800ÚC to 850ÚC and undergoes IGSCC and weld degradation. The retort is operated at an internal pressure of 5 psig and carries a tensile load of around 6 tons at 850ÚC. Hence these reduction retorts are subjected to in-service inspection (visual inspection and radiography of hot zone welds) after 40 runs and thereafter at regular frequencies to assess the healthiness of the weld joints. During In-service inspection (ISI), in retorts which were welded with ER 310 filler wire, many cracks were observed in the weld between shell and dished end. Inspection of welds during service was carried out using digital radiography by using a panoramic X-ray exposure. In order to find out the cause for the weld degradation and linear defects formation and propagation, failure analysis of the retorts was taken up. The observations in the failure analysis were correlated with the fabrication history, operating data and in-service inspection data. With this the mechanisms of weld degradation were identified and recommendations were made to improve the life of the retorts. The use of E 310 Mo welding consumables, modification of process conditions and fabrication procedures resulted in improvement of the life of the reduction retort. (author)

[en] Full text: With ever increasing water scarcity, many alternatives are being tried to supplement the existing water resources. There are regions where water is scarce and population is growing and is at the mercy of inadequate supplies. Seawater constitutes a practically unlimited source of saline water. When desalted, it can augment the existing potable water resources for the people in nearby area and also meet the increasing demand. BARC has been engaged in the field of desalination and developed expertise in both thermal and membrane technologies. It has setup 6300 M³/D Nuclear Desalination Demonstration Project (NDDP) at Kalpakkam, where both membrane and thermal technologies have been used for sea water desalination. Desalination process needs energy and nuclear energy is strong option in view of limited fossil fuels and environmental concerns. Multi Stage Flash (MSF) plant based on thermal technology has been coupled to MAPS Reactors and Sea Water Reverse Osmosis (SWRO) plant is based on membrane technology. This paper discusses various aspects of coupling of desalination plant with nuclear reactors and also discusses salient features of hybridization of thermal and membrane technologies

[en] Nuclear Fuel Complex (NFC), Hyderabad is the sole manufacturer of fuel for Pressurized Heavy Water Reactor (PHWR) in India. The fuel production was progressively increased due to commissioning of new nuclear power plants and operating the existing ones at design load factors. In order to carry out inspection of millions of components to meet the increasing fuel production requirements, NFC has indigenously developed several automatic and semi-automatic inspection systems. These include systems for fuel pellet density measurement, pellet visual inspection, ultrasonic testing for PHWR end closure welds, PHWR fuel bundle backfilling and leak testing with Helium recirculation and bulk metallographic sample preparation. Introduction of these systems have enhanced inspection throughput with higher reliability while reducing human fatigue and monotony. The paper brings out various details of the various systems and their benefits. (author)

[en] The present study deals with the effect of uniform transverse magnetic field on free convection transient flow of an incompressible, electrically conducting, viscous liquid through a porous medium confined in a vertical channel when a wall of the channel suddenly starts to move along the flow of fluid with uniform velocity in its own plane while the other is at rest. The velocity field, temperature field, skin-friction and rate of heat transfer have been obtained following Laplace transform technique. The effects of magnetic parameter, porosity parameter and time parameter on velocity and skin-friction are discussed. The problem of Jha has been deduced as a particular case of the present study. (author)

[en] Full text of publication follows. Background: the prerequisite of radioimmunotherapy is stable binding of a radionuclide to monoclonal antibodies, which are specific to the tumor-associated antigen. Most B-cell lymphomas express CD20 antigen on the surface of the tumor cells, making it a suitable target for therapeutic radioactive monoclonal antibodies. In the present study, the immuno-conjugate of Rituximab and macrocyclic chelator, p-SCN-Bz-DOTA, was prepared and radiolabelled with Lutetium-177 followed by quality control procedures. Methods: Rituximab was desalted with sodium bi-carbonate (0.1 M, pH 9.0) and incubated with DOTA-SCN (1:50). The effectiveness of the conjugation was evaluated by determining the number of chelators per antibody molecule. This conjugate was radiolabelled with Lutetium-177 and purified using PD10 column. The quality control parameters like pH, clarity, radiochemical purity, in-vitro stability and pyrogenicity were studied. Immunoreactivity of ¹⁷⁷Lu-DOTA-Rituximab was assessed using RAMOS cells. The radio-immuno-conjugate (RIC) after stringent quality assurance was injected in three patients and the biodistribution profile was analysed. Results: an average of 4.02 ± 1.04 p-SCN-Bz-DOTA molecules could be randomly conjugated to a single Rituximab antibody. The radiochemical purity of the labelled antibody was >95 % with preserved affinity for CD20 antigen. The final preparation was stable up to ∼120 hours when tested under different conditions. Bacterial endotoxin level in the sample was less than the permissible levels(<0.2 EU/ml). A favourable biodistribution profile was observed with liver showing the maximum uptake of the RIC. Conclusion: a favorable radiochemical purity, stability and biodistribution of the radiolabelled immuno-conjugate indicated that ¹⁷⁷Lu-DOTA-antiCD20 antibody-Rituximab might be a promising therapeutic agent for the treatment of relapsed and refractory Non Hodgkin's Lymphoma. (authors)

[en] Advanced Fuel Fabrication Facility, B.A.R.C., Tarapur has been fabricating MOX fuel for thermal reactors like Boiling Water Reactors (BWR), Pressurized Heavy Water Reactors (PHWR) and fast breeder reactors like Fast Breeder Test Reactor (FBTR), Prototype Fast Breeder Reactor (PFBR). Presently, MOX a fuel for PFBR is being fabricated vide powder pelletisation route (POP route) involving cold-compaction and sintering. MOX fuel pellets of two different enrichment are used for PFBR i.e. depleted UO_2-with 21% and 28% PuO_2 respectively. At present, AFFF is engaged in fabrication of 21% PuO_2 enriched fuel. This paper discusses the experience gained during fabrication of PFBR annular fuel pellets for the initial few assemblies and describes the application of reusing reduced CRO of PHWR and BWR pellets for PFBR