The Nuclear Fuel Complex (NFC), Hyderabad, India was established in 1971 as a major industrial unit of Department of Atomic Energy (India), for the supply of nuclear fuel bundles and reactor core components. It is a unique facility where natural and enriched uranium fuel, zirconium alloy cladding and reactor core components are manufactured under one roof. NFC symbolizes the strong emphasis on self-reliance in the Indian Nuclear Power Programme.
India is pursuing a three stage nuclear power programme linking the fuel cycles of Pressurised Heavy Water Reactors (PHWR ) and Liquid Metal Cooled Fast Breeder Reactors (LMFBR). In addition, Light Water Reactors (LWR ) have also been included in the programme in order to achieve the target of 20,000 MWe of nuclear power by the year 2020
From the very inception of the nuclear power programme in India in the mid 1960s, great emphasis has been given towards self-reliance and indigenisation in fabrication of nuclear fuels.
Ever since its commissioning in 1971, the Nuclear Fuel Complex (NFC ) is playing a key role in this programme and has been supplying natural and enriched Uranium Oxide fuels and Zirconium alloy core components for all the power reactors in India. Indigenous resources, knowhow, and process equipment are being extensively utilized.
NFC is perhaps the only facility in the world wherein under the same roof, both Uranium Oxide fuels and Zircaloy alloy components are fabricated starting from the basic raw materials namely Magnesium-di-uranate and Zircon sand respectively.
In addition, NFC has manufactured and supplied stainless steel core components for the Fast Breeder Reactor programme, Seamless alloy steel and Titanium tubes and other special high purity materials for both nuclear and non-nuclear applications.
NFC has a highly qualifed and committed team of Scientists, Engineers and Technicians. This resource, combined with state-of-the-art equipment and technology and total quality management objective, NFC is poised to meet challenges in the years to come.
Natural Uranium is mined in the uranium mines around Jaduguda in the Singhbhum area of Jharkhand state is converted into nuclear fuel assemblies. A 220 MW PHWR fuel bundle contains 15.2kg of natural uranium dioxide. Uranium dioxide pellets, which generate heat while undergoing fission, also generate fission products. The fission products, which are radioactive should be contained and not allowed to mix with coolant water. Hence the UO2, pellets are contained in Zirconium alloy tubes with both the ends hermatically sealed.
Located near the famous shrine of Moulali at Hyderabad, NFC is spread over an area of 150 acres. Production in its various plants started in the early seventies. Presently NFC has around 3700 personnel.
India is pursuing an indigenous three stage Nuclear Power Programme involving closed fuel cycles of Pressurised Heavy Water Reactors (PHWRs) and Liquid Metal cooled Fast Breeder Reactors (LMFBRs) for judicious utilisation of the relatively limited reserves of uranium and vast resources of thorium. PHWRs form the first stage of the Power programme which uses zircaloy as clad & Natural uranium dioxide as fuel. In addition, India is operating two Boiling Water Reactors (BWRs) for the last 30 years. The zircaloy clad enriched uranium oxide fuel elements and assemblies for these reactors are fabricated at NFC starting from imported enriched uranium hexafluoride.
Uranium Refining and Conversion
The raw material for the production of PHWR fuel in NFC is Magnesium Di-uranate (MDU) popularly known as 'Yellow Cake'. The MDU concentrate is obtained from the uranium mine and milled at Jaduguda, Jharkhand, operated by Uranium Corporation of India Limited (UICL). The impure MDU is subjected to nitric acid dissolution followed by solvent extraction and precipitation with ammonia to get Ammonium Di-uranate (ADU). By further steps of controlled calcination and reduction, sinterable uranium dioxide powder is formed which is then compacted in the form of cylindrical pellets and sintered at high temperature to get high density uranium dioxide pellets. For BWRs, the enriched uranium hexafluoride is subjected to pyrohydrolysis and converted to ammonium di-uranate which is treated in the same way as natural ADU to obtain high density uranium dioxide pellets.
The source mineral for the production of zirconium metal is zircon (zirconium silicate) available in the beach sand deposits of Kerala, Tamil Nadu and Orissa and is supplied by the Indian Rare Earths Ltd. Zircon sand is processed through caustic fusion, dissolution, solvent extraction (to remove hafnium), precipitation and calcination steps to get zirconium oxide. Further, the pure zirconium oxide is subjected to high temperature chlorination, reactive metal reduction and vacuum distillation to get homogeneous zirconium sponge. The sponge is then briquetted with alloying ingredients and multiple vacuum arc melted to get homogeneous zircaloy ingots which are then converted into seamless tubes, sheets and bars by extrusion, pilgering and finishing operations.
For PHWR fuel , the cylindrical UO2 pellets are stacked and encapsulated in thin walled tubes of zirconium alloy, both ends of which are sealed by resistance welding using zircaloy end plugs. A number of such fuel pins are assembled to form a fuel bundle that can be conveniently loaded into the reactor. The fuel bundles for PHWR 220 Mwe and PHWR 500 Mwe consist of 19 and 37 fuel pins respectively. For BWRs, two types, namely 6x6 and 7x7 array fuel assemblies are fabricated.
Seamless Tubes, FBR Sub-assemblies and Special Materials
The Stainless Steel Tubes Plant and Special Tubes Plant at NFC produce a wide variety of stainless steel and titanium seamless tubes for both nuclear and non nuclear applications. NFC is supplying sub-assemblies and all stainless steel hardware including tubes, bars, sheets and springs for the operating FBTR and the forthcoming PFBR. The Special Materials Plant at NFC manufactures high value, low volume, high purity Special Materials like tantalum, niobium, gallium, indium etc., for applications in electronics, aerospace and defense sectors.
Fabrication of Critical Equipment
A notable feature at the Nuclear Fuel Complex is that, apart from in-house process development, a lot of encouragement is given to the Indian industry for fabrication of plant equipments and automated systems. Major sophisticated equipments fabricated in-house at NFC include the slurry extraction system for purification of uranium, high temperature (1750 deg C) pellet sintering furnace, vacuum annealing furnace, cold reducing mill, split spacer and bearing pad welding machines, automatic tube cleaning station, etc. In addition to this, several services like vacuum arc melted alloys production, seamless tube extrusion and finishing, production of tools, NDT services, etc., are undertaken.
Waste Management, Health and Safety
By means of an elaborately organised programme of effluent management, NFC takes scrupulous care in protecting the environment. The Health Physics Unit, the Safety Engineering Division and Environment and Pollution Control Group keeps a continuous watch to ensure that the radioactive and chemical discharges are much below the threshold limits. Rich greenery has been developed in NFC site which is being nourished with treated waste water from the production plants.
Self Reliance The Nuclear Fuel Complex is an outstanding example of a successful translation of indigenously developed processes to production scale operations. The strong base of self-reliance in the crucial area of nuclear fuel and core components is a great asset to the country in not only supporting the nuclear power programme but also in developing a large number of allied and ancillary industries.
The complex has different types of production facilities which include the Zirconium Oxide Plant for processing of Zircon to pure Zirconium oxide; the Zirconium Sponge Plant for conversion of Zirconium oxide to pure sponge metal; facilities for reclamation of zircaloy mill-scrap; the Zircaloy Fabrication Plant for producing various zirconium alloy tubings and also sheet, rod and wire products; the Uranium Oxide Plant for processing crude uranium concentrate to pure uranium di-oxide powder; the Ceramic Fuel Fabrication Plant for producing sintered Uranium oxide pellets and assembling of the fuel bundles for the PHWRs; the Enriched Uranium Oxide Plant for processing of imported enriched uranium hexafluoride to enriched uranium oxide powder; the Enriched Uranium Fuel Fabrication Plant for producing enriched UO2 pellets and the fuel assemblies for the BWR reactors; and a plant for fabrication of components and sub assemblies for Fast Breeder Reactors. A Special Materials Plant for producing a number of electronic grade high purity materials for supplies to the Electronic Industry and plants producing stainless steel seamless and other special tubes have also been set up in this complex.
The common plant facilities comprising of the Quality Control Laboratory, the Central Workshop, the Compressor and Boiler House, the Civil, Electrical and Mechanical Engineering Services render strong support to the Plant operations.
While the individual plant capacities were designed to match the requirements of the Indian Nuclear Power Programme as projected in the early '70s the capacities have been under continuous review. With the experience gained in the operation of various production plants, process and equipment modifications have been incorporated to progressively improve plant performance. The stage has now been reached for substantial increase in capacities and plans have been drawn up for establishing new plants to cater to the requirements of fuel and zircaloy for the 6,000 Mwe Indian Nuclear Power Programme to be implemented in this decade.
An important feature at the Nuclear Fuel Complex, is that, apart from indigenous process development , a good portion of the plant equipment for the chemical engineering and extractive metallurgy operations has been indigenously designed and fabricated by the Indian industry. Even in the case of fabrication plants, sophisticated equipments such as Vacuum Annealing Furance, the Pilger mill, the High Temperature Hydrogen welding units have been successfully designed and fabricated in-house.