NUCLEBRAS SUPERINTENDÊNCIA GERAL DE PROSPECÇAO E PESQUISA MINERAL ATOMIC INDUSTRIAL FORUH/CANADIAK NUCLEAR ASSOCIATION INTERNATIONAL CONFERENCE ON URANIUM QUEBEC / CANADA SEPTEMBER 15-17/81 BRAZILIAN URANIUM EXPLORATION PROGRAM AUIHOR: -JOSÉ PAULO PANSUR PARQUES CONTENTS. SECTION PAGE ABSTRACT 1. INTRODUCTION 01 2. GENERAL INFORMATION ON BRAZIL'S URANIUM EXPLORATION PROGRAM 02 3- MAJOR BRAZILIAN URANIUM DEPOSITS 05 3.1 The Figueira Deposit 05 3.2 The Alkaline Intrusive Rocks of Brazil 08 3.3 The Poços de Caldas Alkaline Complex (Campo do Cercado Deposit or Osamu Utsumi Mine) 10 3.4 The Lagoa Real Uranium District 18 3.5 The Central Ceará Uranium-Phosphate District 20 3.6 The Itataia Deposit 21 4. CONCLUSIONS 23 5- M^ilPiMDGEilLNJl 27 6. RF.fERENCES 28 BRAZILIAN URANIUM EXPLORATION PROGRAM ABSTRACT Due to the growing demand of electric power to support :~azil's development as well as the constant price raises of fossil fuels and the scarcity of additional hydroelectric resources, the use of nuclear energy will be indispensable. The nuclear fuel cycle for the production of energy starts with the exploration for uranium ores. The work performed in this field led to the discovery of several ore deposits in the country such as: FIGUEIRA/PARANfl ^Middle Permian sandstones of the Paraná Basin), POÇOS DE CALD-S/MINAS GERAIS (alkaline rock of Up; er Cretaceous age)-which will be in operation late in 1981 with Ô nominal capacity of 500 tpy of U308-t QUADRILÁTERO FERRÍFERRO/MINAS GERAIS (metaconglc .erates in Precambrian domain), LAGOA REAL/BAHIA (metasomatites/ 1 inear albitites in Precambrian rocks), AMORINCPOLIS/GOIAS (i^vonian sandstones of the Paraná Basin), CAMPOS BELOS -RIO PRETC /GOIAS (vein unconformity type in Precambrian rocks), ESPINHARA5/PARA2 BA (metasomatites in Precambrian domain), and ITATAIA/CEARfl (metasomatites in Precambrian domain also). Brazil's total uranium reserves amount presently to 236,300 tonnes of U308 placing the country, probably, as the 6th largest reserve in the western world. This tonnage is equivalent :o 1,645 Mtep and enabling the supply of 40Angra-2 type (1245 MWe) -.uclear power plants over its 30 years lifetime. 0) 1. INTRODUCTION The Sudden raise in petroleum prices in 1973 had a signifi- cant impact on the brazilian economy. In 1930 almost 48% of the net income from the country's export where absorbed by the imported oil. Consequently, problems with the balance of payments occured, inflation rose and GNP index fell. The perspectives of soaring prices of the fossil fuels and, in the long range, the physiccl exhaustion of the hydroelectric energy sources, compelled the brazilian government to look for a diversification in energy sources within the country. Thus, combining energy preservation policies, enlarged emphasis on the exploration and exploitation of the domestic oil and coal reserves, the government defined, in 1974, the Brazi 1 ian Nucle- ar Program both to secure and provide the country with the electric po.er required for its development , as well as the technology of the entire nuclear fuel cycle (FIG.l).A Cooper- ation Agreement with Western Germany for the transfer of nucle- ar technology was signed in 1975 as part of this Program. Several orçsnizations take part in this rroçram each with its own attribution (FIG.2). The present status of the Brazilian Nuclear Program is as follows: U r a n i u m Exp_7orati on - is being carried out and right now the uranium reserves amount to 236,300 t of U3O8. Urani um _Min*'_n_£ - the first brazilian uranium mine and mill is in its final construction phase at Poços de Caldas and will be brought into operation in the last quarter of 1981. The mill's nominal capacity is 500 t/year of J3OS. Other deposits are scheduled to come into production in '86, '87 and '88. Conversion ?1a_n_t - it is, presently, in the engineer! ng stage. 02 Enrichrsnt Plant - the jet-nozzle process demonstration plant is 'jncer construction and is scheduled to be operating at the end of 1983 (first cascade - 24 stages) and reaching its final zapacity Of 80 tonnes of SWU in 1986. The second oneis scheduled for 1988, with a capacity of 300 tonnes SWU. Fuel Element Fabrication Plant - the first stage (assembly fuel clement) is already built; the second one is scheduled for li;4 and the third one for 1985. Heavy Coni£onents Fabrication Plant - it started operations in 1980 end is now producing heavy components ( pressure vessel, pressurizers , steam generators, etc) for NPP3 and NPP4 and for Atjcha 2 (Argentina). iiy^L^f^^!.^--!! " the first brazilian PWR - WESTINGHOUSE NPP (f?8 MWe) will be brought into production by the end of this year. The second one PWR-KWU (1245 MWe) is in the initial construction stage of the pressure vessel building while the, foundations for the third one are being laid out. In January the geological studies to select the sites of ÍÍPP4 and NPP5 (FIG.2) were started. Total investments for the Brazilian Nuclear Program, until 1995, are estimated at US$ 17,5 billion, of wh:ch 13,5 bi11 ion for tta nuclear power stations and 4,0 billion for the restof nuclear fuel cycle. 2- íl^MJÍL^J^ILPILM iLTi exploration has been carried out in Brazil since 19b2 with particular emphasis during the last six years. An initial objective was the evaluation of the uranium re- sources associated with zirconium ores (caldasite) of the Po- ços de Caldas Plateau. 03 Until 1970 uranium exploration was mostly confined to the Paleozoic and Mesozoic sedimentary basins. However it should be noted that some reconnaissance was carried out in the Pre- cambrian domains as well, and this led to the selection of large areas for aerogeophysical surveys. From 1974 to 1978 there was a significant increase inairborne camma-ray surveys over the Precambrian basement which amounted to 3,000,000 kro2 of a total area of 4,300,000kra2 ofPrecambrian rock units. The promising results of those surveys led to shift in empha- sis from the sedimentary basins to the Precambrian domains and this shift resulted in areas in variety of geological environ- rents wich were delimited for detailed studies, including the new deposits located at Itataia and Lagoa Real In northeastern part of the country. In the figures 4 and 5 it can be seen the development of u- reniura exploration work during the last years. The rapid progress made after 1975 (when known reserves amounted to 11,040 t of U308) in the identification and exploration of uraniferous districts can be attributed to the growth of funds and the following of a rational sequence of stages wich include: «) Regional Geology. The selection and verification of po- tentially favourable areas following integrated studies based on all available information. Geological thinking is a fundamental aspect of this stage. b) Prospection and Exploration. This stage follows asa conse- quence of the preliminary studies. Specific programs are established in favourable areas based on the use of tra- ditional prospection methods. Preliminary feasibility studies are also carried out during this stage, including 04 ore reserves estimation and economic evaluation. With respect to the philosophy of evaluation , it should be noted thft all prospects are evaluated irrespective of the degree of mineralization but taking into account their po- tential so that expenditures are not in excess to what mey be found. The estimation of reserves is based not only on conventional techniques (blocks, isolines, parallel sections, etc.) , but also on statistical and geostatistical methods such as Kriging and Cokriging using available computer programs de- veloped by NUCLEBRfiS. The use of these var.u..s techniques both , consecutively and simultaneously, permits a high degree of precision in the evaluation (FIG.6) (Marques et alii, I960). The concept of "Measured Reserves" and "Indicated Reserves" (Reasonably Assured), and "Inferred Reserves" (Estimated Ad- ditional) is based on a serias of criteria. These include the estimation methods used, the regularity of the sampling grid, the grid spacing, the percentage of core recovery, the re- lationship between the number of chemical andradiometric data from the mineralized horizons, the degree of co-relation of the regression line between radioactivity and chemical grade, and, finally, the relative error with respect to the most probable value of U3O8 tonnage at the 95*confidence level. It should be emphasized that the maximum value of the errors considered are compatible with the class of reserves reported, and that, for Measured Reserves, one of the techniques always used is geostatisti cs. Also for Measured Reserves,the relation- ship used between data from chemical and radiometric analysis is much greater than that internationally adopted. These computations are greatly facilitated by delayed neutron analysis for U3O8 which permits a large number of samples tobe processed quickly. 05 Reported reserves are defined as those economically viable on the basis o* an international value of US$ 40.00/lb U3O8. The work dors up to now led to the evaluation of reserves as show in figures 7 and 8. 3. MAJOR BRAZILIAN URANIUM DEPOSITS The major b-dzilian uranium deposits (FIG. 9) are in different stages of e»aluation and development. The large deposits at Poços de Ca'das, Figueira, Itataia, and pert of Lagoa Real are scheduled for exploitation. The deposits at Espinharas, Amcrinõpolis and part of Lagoa Real are being enveloped and those ones at Rio Preto, Campos Belos and QuadriHtero FerrTfero are still in an early stage of in- vestigati on. This paper Ascribes only the most important deposits: Figuei- ra, Poços c-. Caldas (Osamu Utsumi Mine), Lagoa Real and Ita- taia. 3.1 The Fiç.âira Deposit The Fiç.eira uranium deposit is located in the north- central part of the State of Paraná close to the village of the .:3me name, 300 km northwest of Curitiba, in a region ;f undulating relief.