The nuclear power programme of the country is a three stage programme. The first stage of this programme is based on Pressurised Heavy Water Reactors (PHWR) which are fuelled by natural uranium.The requirement of natural uranium for these reactors is met from the indigenous resources established by AMD. The second stage envisages utilization of plutonium produced and re-processed from the first stage. The third stage is based on thorium for which not only some breakthrough has been achieved but also further R&D effort is in progress. The requirements of thorium would be met from vast resources of the mineral - monazite (a thorium, REE phosphate).
The work spectrum of AMD is closely linked to different phases of nuclear fuel cycle, viz.
||survey for identification of atomic mineral deposits
||site selection for nuclear power reactors
||selection of suitable sites for waste disposal
The front-end activities are of major importance and are carried out in the field with adequate laboratory support. The principal activity is to identify three major group of resources viz. (i) uranium, (ii) rare metal and rare earths (Nb-Ta, Ce, Be, REE, Y), and (iii) beach sand minerals containing minerals of thorium, titanium and zirconium.
The field activities commence with remote sensing studies / airborne surveys (ASRS) followed by ground geological, geochemical, geophysical surveys (EGPG) on different scales.Once ground anomalies have been established by these methods, their subsurface continuity is probed by core / non-core drilling and rarely by exploratory mining. The laboratory studies are carried out simultaneously to evolve models for exploration and for optimising the recovery parameters. Once a deposit is established, it is handed over to Uranium Corporation of India Limited (UCIL) for commercial exploitation.
The mineral resources included in this group are columbite-tantalite, beryl, spodumene, lepidolite and xenotime which generally occur in pegmatites and riverine placers. The field investigations commence with survey, followed by pitting / sampling to estimate the grade of the occurrence. These minerals are then won by excavating gravel portion of the pegmatites and by setting up on-site small-scale recovery plants. Separation of these minerals is done by physical beneficiation methods and the recovered minerals are stock piled in the godowns of the Directorate.
The beach sand minerals comprise of ilmenite, rutile, zircon, monazite, garnet, and sillimanite which occur in different concentrations along various coastal stretches of the country. These mineral resources are sampled by auger drilling, conrod bunka drilling, dormer drilling and reserves are estimated by mineralogical analysis of both individual and composite samples. These resource estimates are parted with Indian Rare Earths Limited (IREL) and other state government / private entrepreneurs on commercial terms.
In order to support the above investigations, the Directorate is equipped with various laboratories both at AMD headquarter and regional centers. They not only provide useful information to the field units but also design, develop, fabricate and maintain many of the instruments required in the exploration programme.
While in each Region there is a Physics, Chemistry and Petrology laboratory, in the Headquarter at Hyderabad, there are other laboratories also often functioning as a Group, viz.
Mineral Technology laboratory
Winning of minerals from the earth involves alteration of environmental parameters and has always been a concern for the mankind. Atomic minerals, especially uranium, being radioactive the concerns of environment draw more attention. However, considering the fact that uranium is packed with abundant energy, for comparison, 1 kg petroleum products produce 4 KWh electricity whereas 1 kg of natural uranium produces 50,000 kwh electricity the importance of winning this metal from the earth assumes all the importance.
For planning and initiating remedial measures, if any, in a mining activity, pre-project environmental data is therefore essential. In the recent years, AMD has been generating the pre-project environmental baseline data around the potential mining sites.
Towards the back-end activities, AMD is associated with the site selection for nuclear establishments
Nuclear Power Plant sites are subjected to stringent evaluation at every stage from regional analysis to site specific investigations, for which AMD carries out geotechnical studies during pre-construction stage. It collates the available geological and seismotectonic data for 300 km radius area around the site. Seismotectonic maps on suitable scales are synthesized, ‘Active Faults’ identified and the earthquake potential of the structural elements and seismotectonic provinces is evaluated. Remote sensing studies using satellite imageries and aerial photos followed by limited field check are supportive supplements in this work. The output of this endeavor has application in deriving the seismic parameters that are used in the design to strengthen the foundation and the structure to withstand the heavy loads and seismic shaking. Similar studies are carried out for the sites for Heavy Water Plants, Tailings Ponds and Irradiation Plants.
In the selected sites geological mapping of the reactor pits, lithologging, petrographic studies of the borehole cores and base-line radiation data collection are carried out.
Nuclear industry generates radioactive waste (RAW). Ultimate disposal of this waste is done in suitable geological environment. Consequently comprehensive geological study in relation to all aspects of storage / disposal of RAW is a must before final selection of sites of radioactive waste repository. AMD extends the cooperation in the site selection of repositories, drilling of the candidate sites and studying of the core samples in order to evaluate the subsurface conditions, petromineralogical characteristics and to generate samples for the testing of engineering properties. Expert opinion is offered to the end user on the investigative geological reports submitted by other agencies.
In addition, some of the miscellaneous activities carried out by AMD are as under
1. Site specific background radiation surveys were carried out in Goa and Nepal for M/s. Kodak India Pvt., Ltd., for their photographic film storage plants.
2. Radon Emanometry surveys were carried out in and around Khilari following the 1993 earthquake and the radon anomalous behaviour had shown coherence in time with seismic events.
3. As a member of the Task Force, AMD has contributed to the revision of IS code in bringing about the ‘Criteria for earthquake resistant design of structures, Part.1 General Provisions and Buildings (Fifth Revision), IS 1893 (Part-1): 2002.
4. AMD contributes in the formulation of codes of AERB pertaining to geological and seismological aspects and was a member of Expert Committee for Seismic Qualification of existing DAE installations (ECSQ).