India’s quest for nuclear fuel10 September 2019
India has always had ambitions to become self-sufficient in nuclear fuel production. Saurav Jha reviews recent developments in the country, including plans to increase uranium production ten-fold by 2032.
AS PART OF ITS THREE-Stage Nuclear Programme (TSNP), India’s Department of Atomic Energy (DAE) has been progressively scaling up front-end activities related to a uranium-238/plutonium-239 based closed cycle.
The eventual goal is al ‘self-sustaining’ thorium-232/ uranium-233 closed cycle. Since India’s TSNP grew amidst years of isolation from international nuclear trade, self-reliance in the techno-industrial aspects of closed fuel cycles is a core aim. Today DAE is one of the few nuclear estates that has expertise across the range of activities that constitute the front end of the nuclear fuel cycle, including mineral exploration, mining and processing, heavy water production and fuel fabrication. India is self- sufficient in production of heavy water, zirconium alloy components and other materials, and supplies for PHWRs. India also has some uranium enrichment capability, which it is now looking to enhance via a new facility. The scaling up of front-end fuel activities is alongside the aim of putting in place at least 22.5GWe of nuclear power generation capacity by 2031.
India has access to uranium imports from abroad and fourteen Nuclear Power Corporation of India Limited (NPCIL) reactors, which have a total installed capacity of 4380MWe, are currently operating on imported fuel. Units running on imported fuel are all safeguarded reactors.
Only the remaining eight ‘out of safeguards’ reactors in NPCIL’s fleet, with a total capacity of 2400MWe, are fuelled with domestically mined uranium.
Since 2008 fuel imports have gone a long way in restoring NPCIL’s power plant performance in terms of their plant load factors. Nevertheless, DAE is seeking to reduce dependence on foreign sources for fuel. Instead, it wants to increase domestic uranium production ten-fold by 2031/32, while simultaneously building up a strategic uranium reserve. In the past, DAE said that a stockpile of 15,000t uranium would suffice to provide security of supply for India’s nuclear reactor fleet in the medium term.
DAE’s Atomic Minerals Directorate for Exploration and Research (AMD) has been carrying out extensive radiometric, geochemical and geophysical surveys across India to scour for new uranium deposits. Among the latest prospects being explored are a small tonnage deposit in Naktu, Uttar Pradesh and potential deposits in Betul, Madhya Pradesh. The Uranium Corporation of India Limited (UCIL), as part of agreements with AMD, is also conducting activities related to exploratory mining at Rohil in Rajasthan, Singridungri Banadungri in Jharkhand and Peddagattu in Telangana. As of May 2018, AMD had established 300,034t of in situ U3O8 reserves in 44 low- grade uranium deposits across India.
Mining and milling
As new U3O8 reserves are being explored, DAE has been looking to step up mining and ore processing activities. UCIL, which is responsible for mining and milling of uranium in India, has accordingly been on a path of expansion. In June 2019, the company revealed plans to invest in 13 new domestic mining projects with a total outlay of Rs105.70 billion ($1.52 billion). These new projects, once online, are expected to quadruple total domestic uranium production. Apart from these new projects, UCIL is also working towards capacity expansion at some existing units.
UCIL presently operates seven mines in the state of Jharkhand at Jaduguda, Bhatin, Narwapahar, Turamdih, Bagjata, Banduhurang and Mohuldih. It also has two processing plants in Jharkhand co-located with the mines at Jaduguda and Turamdih. Capacity expansion and ‘debottlenecking activities’ are under way in some of its oldest mines in Jharkhand. The company’s relatively new mine at Tummalapalle, Andhra Pradesh, is also being augmented for greater efficiency. This mine has achieved full production capacity and a co-located processing plant has also been delivering output.
UCIL’s processing plants at Jaduguda and Turamdih use standard acid leach techniques for the production of yellow cake or magnesium diuranate (MDU). However, the plant at Tummalapalle, which has a peak capacity of about 3000t/d, uses an alkaline pressure leach process technology to produce sodium diuranate (SDU). Recently, a re-dissolution system (RDS) facility at the Tummalapalle processing plant became operational. Commissioning marked the culmination of several years of work by DAE scientists seeking a useful technique for settling and complete recovery of precipitated product by sending a part of it to precipitation tanks. A new leaching process that can be used to obtain yellowcake from crude SDU- phosphoric acid leach solution has also been developed.
Nuclear Fuel Complex
The output of UCIL’s processing plants, whether MDU or SDU, ends up at the Nuclear Fuel Complex (NFC), Hyderabad, which is India’s key fuel fabrication facility. Any uranium imports, whether in the form of MDU, enriched uranium hexafluoride (UF6) or uranium dioxide (UO2) pellets (both enriched and unenriched) are also sent to NFC for fuel fabrication. This has put several of its units under safeguards since 2008. NFC first converts and refines MDU into UO2 powder which is then pelletised. The pellets are put into elements which are then assembled to form PHWR fuel bundles by using contemporary welding, machining and assembly techniques. In the past, NFC has fabricated PHWR fuel of varying designs, such as the 19-element wire wrap, 19-element split spacer, 22-element split spacer and a 37-element split spacer, all of which contain natural UO2 pellets.
In recent times, NFC’s main unit at Hyderabad has been churning out record amounts of PHWR fuel on a yearly basis. In 2018, NFC produced and handed over its millionth PHWR fuel-bundle to NPCIL. The fiscal year 2018/19 also saw NFC recording its highest ever production of 37-element production — 365t. For NFC, another notable achievement was the supply of 37-element fuel bundles of modified bearing pad design to the 700MWe Kakrapar 3, which is scheduled to begin commercial operation by 2022.
By the mid-2020s, NFC seems set to further augment its PHWR fuel-fabrication capacity by commissioning a new complex at Kota, Rajasthan. This greenfield facility, called NFC-Kota, will initially be able to fabricate 500t/yr of UO2 pellets and 65t/yr of Zircaloy products. Foundation works for this new facility have been completed and work on plant and administrative buildings is underway. Meanwhile, the Enriched Fuel Fabrication Plant at NFC, Hyderabad, which is used to fabricate 36 and 49-rod fuel assemblies with enrichment levels of 2.66%, 2.1% and 1.6%, respectively, for NPCIL’s two BWRs, Tarapur 1&2, has begun delivering about a hundred fuel-assemblies on an annual basis. This facility is also used for de-canning rejected PHWR fuel elements to recover UO2 pellets to be loaded into fresh fuel tubes.
Uranium enrichment capability
Over time, DAE intends to supply this facility with domestically enriched uranium. India currently operates a small enrichment plant at Ratenhalli near Mysore in Karnataka, which uses gas centrifuge technology, and is primarily meant for military purposes. However, its capacity is being expanded to 25,000 separative work units per year (SWU/yr) and it does provide limited quantities of enriched compounds to the research and power generation programmes. In the near future, it is likely to supply some slightly enriched uranium (SEU) for India’s PHWRs as well.
A much larger enrichment plant, called the Special Material Enrichment Facility (SMEF) is under construction at Challakere, Karnataka. It too will use mature gas centrifuge technology. SMEF is expected to contribute in a major way to India’s power generation programme. DAE is also pursuing R&D on laser enrichment techniques.
The steady growth in PHWR fuel production mentioned above necessitates a commensurate increase in output from NFC’s other major stream of nuclear related activity, the so-called ‘zirconium stream’. This is manufacturing of various zircaloy clad tubes and components used to create fuel assemblies, through a series of steps that begins with the conversion of zirconium sand, supplied by the DAE controlled Indian Rare Earths Limited (IREL) to nuclear grade zirconium oxide (ZrO2) powder.
NFC’s Zirconium Oxide Plant (ZOP) in Hyderabad has been undergoing steady modernisation and recently completed the commissioning of a high-capacity pulveriser unit, which has enhanced its capacity for grinding ZrO2 to 500kg/hr. ZOP’s control and instrumentation systems are also being upgraded. Meanwhile, NFC’s zirconium unit, the so-called Zirconium Complex (ZC), at Pazhayakayal, Tamil Nadu, has been steadily scaling up output of zirconium sponge and is likely to attain its design capacity of 250t/yr in the near future.
Heavy water production
A critical aspect for the PHWR fleet expansion is the uninterrupted supply of heavy water (D2O). DAE’s Heavy Water Board (HWB) is today the world’s largest producer of D2O and its plants have been exceeding annual production targets. In 2018, its largest plant, at Manuguru, completed a major turnaround, as did the plant at Kota. An important factor that determines viability of HWB’s plants is their specific energy consumption, which was found to be 27.9GJ/kg D2O in 2017-18 — below what HWB had budgeted for. At Tuticorin, work is currently underway on a solvent production plant and a solvent extraction plant both of which will be dovetailed to the production of special solvents including organ-phosphorous compounds.
HWB also produces critical inputs for India’s FBR programmes, such as nuclear-grade sodium for coolant purposes and enriched boron. Its boron enrichment and boron carbide pellet facilities, at HWB’s Talcher and Manuguru sites, have already delivered the entire requirement for the first core of the 500MWe Prototype Fast Breeder Reactor located at Kalpakkam. HWB has also developed closed-cell technology to produce sodium, which is used as a coolant in the PFBR. At the moment, work on a 24kA prototype cell is under way. The experience will be used to eventually set up a 600t/yr sodium production plant at Baroda.
NFC’s Fast Reactor Facility (FRF) is currently building ten different types of core sub-assemblies for the PFBR. D9 austenitic stainless steel has been used for the fuel clad tubes and the hexagonal channels, while SS 316 low nitrogen has been used to manufacture bulk components. One noteworthy feature of the hexagonal channels manufactured at NFC is that they are of the seamless variety, while elsewhere in the world these channels are usually seam welded. NFC Hyderabad has also been developing metallic fuels with short doubling time for use in India’s future FBRs. Engineering scale production of Nat-U metal power has already been demonstrated and a uranium metal production facility (UMPF) is set to be built in Vishakapatnam in the 2020s.
Author information: Saurav Jha, Author and commentator on energy and security, based in New Delhi