[en] Boron Carbide enriched in ¹⁰B isotope is used as control rod material for fast reactors. The natural abundance of ¹⁰B isotope of boron is about 20%. In addition to the use in control rods for fast reactors, enriched boron compounds find many other applications in nuclear industry such as in neutron detection, shielding and burnable poison in moderators of thermal reactors and also in neutron capture therapy. To meet the growing demand for ¹⁰B enriched materials, it has become necessary to develop efficient processes to enrich this isotope of boron. Among the known processes, ion exchange chromatography is a viable option for the industrial enrichment of this isotope of boron. Pilot scale experiments were carried out to study the band velocity, influence of complexing agent, variation of HETP with time, influence of initial eed enrichment and particle size of the resin. A Model for ion exchange chromatography was developed and validated to predict HETP for different operating conditions. This model is effective in analysing plant operation and also design of new boron enrichment plants

[en] In view of available natural uranium resources, it is prudent to go for FBRs to produce fuel and also breed new fuel for setting up a series of reactors. Already a 40 MWt Fast Breeder Test Reactor (FBTR) is in operation and a 500MWe FBR is under construction. These reactors use enriched boron as the control rod material. Enriched boron is also used for neutron detectors in all types of reactors. Technology for enrichment of boron is not available due to embargo. Also it is not available in the world market for use in our nuclear program. Indigenous development of enrichment of boron has become an essential requirement of Indian Fast Reactor Programme. Two processes that are known to have been used for enrichment of isotopes of boron are 1) distillation of dimethyl ether complex of boron trifluoride and 2) ion exchange chromatography of boric acid. Kinetics of the former process is fast but availability of raw materials, explosive nature of the chemicals used are some of the drawbacks of the process. Ion exchange chromatography is simple to operate and the raw materials are available in India. Hence, this process was selected for detailed study and development of technology for the production of enriched boron

[en] The results of experiments carried out to study the thermal stability and enrichment performance of type I and type II resin samples obtained from indigenous suppliers are reported in this paper. (author)

[en] Short communication

[en] During the regeneration of tributyl phosphate in uranium plant, a sizable volume of liquid waste containing about 70 mg/l of uranium, along with high concentrations of nitrates and carbonates, is generated. Laboratory studies revealed that the waste was not amenable to conventional treatment methods, including co-precipitation, owing to high concentration of carbonates, with which uranium forms a stable carbonato complex. Various commmercially available strongly basic anion exchangers were evaluated for the uptake of uranium from the waste under static conditions. Column studies, employing the anion-exchange resin which has shown the highest uptake, were carried out. These studies reveal the application potential of ion-exchange process not only in the treatment of uranium bearing wastes but also in the recovery of uranium. (author). 8 refs., 4 figs., 5 tabs

[en] Thermal stability of indigenously available type I and type II anion exchange resins were studied in chloride and hydroxyl forms. The results of the study indicated that the resins under study were thermally stable up to 50 deg C even when heated in an oven for 180 days and there was no appreciable loss in ion exchange capacity of the resins for boric acid. (author)

[en] The paper describes a technique adopted for evaluation and selection of a site for a shallow ground disposal facility for nuclear waste. Parameters of interest are statistically evaluated to locate the most suitable zone for disposal of waste at selected sites. A technique is also presented for conditioning a specific ground disposal facility using magnesium chloride and sodium silicate, which are readily available as by-products for in situ precipitation of magnesium silicate. (author)

[en] The thermal hydraulic design plays a crucial role for the safe and economical deployment of Liquid Metal Cooled Fast Breeder Reactor (LMFBR). Robust experimental programmes are required in support of LMFBR thermal hydraulics design. The philosophy of testing has been to construct small scale models to understand the physical behaviour and to build larger scale models to optimize the component design. The experiments are conducted either in sodium or using a simulant like water/air. The paper gives a brief account of the various thermal hydraulic experiments carried out in support of the design of Prototype Fast Breeder Reactor (PFBR). (author)

[en] Sodium cooled, 500 MWe Prototype Fast Breeder Reactor (PFBR) is under construction at Kalpakkam, India. The core of PFBR is divided into various zones such as fuel, blanket, reflector, storage etc., according to their function and flow requirement. The core subassemblies (SA) are supported vertically inside the core by the sleeves provided in the Grid plate (GP). The foot of the SA is located inside the GP sleeve and a small radial gap exists between sleeve and the foot. It is expected that there will be some leakage flow through this radial gap into hot and cold pools of PFBR. To minimize this leakage flow, labyrinth type sealing devices were developed by carrying out experimental study. This paper presents the details of the similarity criteria followed, experimental methodology and the results obtained from the experiments with their transposability to the reactor conditions. (author)

[en] This paper presents the two dimensional numerical prediction of melting and solidification of the eutectic salt mixture of LiCI and KCI inside the Electrorefiner. In this paper the melting and solidification time is predicted by assuming heat transfer during phase change is only through conduction. The heat due to fusion is added in the equation of specific heat of the salt. Density and thermal conductivity of the solid and molten salt is added together to form a continuous piecewise function. This modification helps in simulation of melting and solidification front. (author)