Atoms in industry

THE panel on display in the foyer of the multi-storey “C” building at the International Atomic Energy Agency’s (IAEA) headquarters in Vienna, Austria, carried the simple headline “Arts meets Nuclear Science”. The delegates, whether they were from Australia, Belgium, Ghana, India, Malaysia, Mauritius, Morocco, Sudan or Tunisia, were stopped in their tracks and compelled to pay attention to its texts and pictures.

“Books, furniture, musical instruments, wooden sculptures and even mummies can be attacked and destroyed by bacteria, fungi, mould and insects,” said a box in the panel entitled “Gamma Irradiation”. “With irradiation, a radioactive source emits powerful gamma rays that can kill them. It does not damage the precious work of art. It is quick and effective, and requires no use of chemicals or quarantine,” it explained.

Museu Afro Brasil, a museum in Sao Paulo, Brazil, has an enviable collection of 4,000 works of art showcasing the history and art of Afro-Brazilian culture. But termites had attacked and ravaged about 100 wooden artefacts. It took gamma irradiation to clear these wooden objects of termites so that they could be restored to their original glory.

An analysis of “The Wounded Man”, a self-portrait by the French painter Gustave Courbet, using X-ray fluorescence spectrometry revealed a secret and a love story. There was a woman leaning on the artist’s shoulder when he first painted it. Ten years later, after the end of the love affair, a sword had replaced the woman, and Courbet had added a bloodstain on the shirt, over his heart.

“Radiography, such as X-rays and CT [computed tomography] scans, allows us to see what is happening inside our bodies,” said a text entitled “Radiography”. “The same radiation technology can be used to look inside a work of art to assess its internal damage. With this information, the restorers know what type of work they need to do and the best tools to use, while avoiding any further breakage,” it added.

Cut to India, hundreds of mango growers are a happy lot since 2007 when the United States lifted its ban on India exporting mangoes to it after a gap of 18 years. Exports had been stopped because mangoes cultivated in India could harbour weevils. Irradiation with gamma rays has ensured the disinfestation of the fruit, which is now exported to the U.S., Japan and other countries. About 3,000 tonnes of mangoes were exported to the U.S. in 2008, the year India resumed mango exports. Exports to the U.S. in the current year are worth approximately $16,00,000.

Irradiation, or radiation processing, involves controlled application of energy of ionising radiation such as gamma rays, X-rays and accelerated electrons on products packed in polyester or gunny bags. At the heart of India’s programme to irradiate agricultural and medical products using radioisotopes is the Board of Radiation and Isotope Technology (BRIT), a low-profile organisation of the Department of Atomic Energy (DAE).

At BRIT’s Radiation Processing Plant at Vashi, Navi Mumbai, in a facility shielded by a two-metre-thick concrete wall, a conveyor belt-like system rolls out shipping cartons with polyester bags containing spices, Ayurvedic raw material, onions and bird and animal feed. They have just been irradiated to destroy the harmful bacteria that may be present in them. Irradiation of spices, fruits, vegetables, and so on, gives them a longer shelf life, ensuring price stabilisation and better returns for farmers. At BRIT’s upgraded facility for quarantine treatment of mangoes and other food products, at Lasalgaon, near Nashik, cobalt-60 gamma radiation is used to process bulbs and tubers to prevent sprouting and to disinfest spices, cereals and pulses of insects.

According to “Radiation, A Fact of Life”, a booklet brought out by the Bhabha Atomic Research Centre (BARC), Mumbai, radioisotopes, which are produced in power reactors, have numerous applications in agriculture, industry, hydrology and medicine. Their applications in industry range from detection of leaks in buried pipelines, study of the wear and tear of machinery to gamma ray radiography to check welds, castings and ceramics. In hydrology and agriculture, radioisotopes are used to study the origin and movement of ground- and surface water. Radioisotopes are also used extensively in the detection and treatment of cancer. According to the booklet, radioisotopes are used to image body organs such as the brain, the kidneys, the liver and the heart to study their functional disorders.

Non-destructive testing

Non-destructive testing (NDT) technology, using gamma radiation, is used in scores of countries to find out the structural integrity of buildings ravaged by fire; to check whether the turbine blades used in aircraft or for electricity generation have suffered metal fatigue; to test the integrity of components in cars, trains and machinery; to probe whether welds in oil/gas pipelines have defects or whether fusion has taken place correctly; to find out whether there are invisible cracks in the thick concrete runways at airports; and so on. It is called NDT because trained technicians can find out what has gone wrong inside an object without taking it apart, that is, without destroying it. In India, the Indira Gandhi Centre for Atomic Research (IGCAR) at Kalpakkam, Tamil Nadu, has put NDT techniques to novel use. According to Baldev Raj, former Director, IGCAR, NDT technology helped find out how the bronze statuette “The Dancing Girl” of the Harappan civilisation was cast, to study the structural composition of 1,000-year-old exquisite Chola bronzes and to investigate why the Iron Pillar at Qutub Minar, near New Delhi, has not corroded. (NDT employs a common tool called radiography, akin to medical diagnostics).

After powerful temblors ravaged Nepal in April 2015, the IAEA has been helping the country use radiography to test the structural integrity of public buildings such as schools, hospitals and government offices. NDT is a burgeoning profession today, and thousands of technicians across the world have been trained in it with the help of the IAEA.

An acoustic monitoring system installed in the Forth Road Bridge, an iconic suspension bridge in east central Scotland, revealed multiple breaks in its main suspension cables. A new bridge is now being built at a cost of about £1.5 billion.

Electron beam accelerators help keep the environment clean and safe. In Bulgaria, China, Malaysia, Poland, the U.S. and other countries, electron beam accelerator facilities treat the exhaust, or flue, gases from coal-fired electricity generation plants, thus reducing emissions of sulphur dioxide, nitrogen oxides, and so on. In many countries, they are used to rid waste water from textile dyeing units, paper mills, chemical industries, and so on, of colour and odour.

Nuclear tracers are used to find out how much oil remains in offshore wells under production. Nucleonic gauges help in detecting narcotics and explosives.

All these topics were the meat of the presentation papers and intensive discussions at the Scientific Forum on “Atoms in Industry: Radiation Technology for Development” held on September 15 and 16 on the margins of the IAEA’s annual General Conference in Vienna. The Scientific Forum attracted the top brass of nuclear establishments, nuclear engineers and scientists, and Ministers from various countries, including Australia, Austria, Belgium, Germany, Ghana, India, Malaysia, Mauritius, Pakistan and Romania. Yukiya Amano, Director General, IAEA, who inaugurated the Forum, put its topic in perspective when he said how nuclear techniques were used to produce items that are often taken for granted in our daily lives. “I suspect that everyone in this room has a smartphone,” Amano said in his opening remarks. “These and other electronic products use high-performance rechargeable batteries. These batteries contain a separator membrane designed to give them longer life. Radiation is routinely used to produce this special membrane.

“Other items which are treated or tested with radiation during manufacturing include buildings, cables, computers, car parts and medical devices.

“Nuclear techniques are used extensively in industry to increase product quality and safety, benefiting both producers and consumers. Radiation tools make industrial production cleaner and more effective.”

The Director General estimated that gamma radiation was used to sterilise up to 40 per cent of all single-use medical products, such as syringes and gloves, in the world.

Amano, who contributed to the 1995, 2000 and 2005 Review Conferences of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and chaired the Preparatory Committee for the 2010 Conference, said: “Radiation cross-linking makes materials such as tyres and cables more stable, durable and resistant. This technique is applied to up to 90 per cent of the materials used to build cars, airplanes and computers. It can also help to create new materials, such as hydrogels to treat burns, and substances that make plants grow more quickly.

“The use of electron beams makes it easier to clean up industrial waste water by removing persistent sources of pollution, such as the dyes used in the textile industry.

“This cost-effective technology can also be used to turn the flue gases produced by coal-fired power plants into useful fertilizers. The IAEA is supporting work on this that is being carried out in Poland.”

Sergey Kirienko, Chief Executive Officer, Rosatom, Russia; Ratan Kumar Sinha, Chairman of India’s Atomic Energy Commission; and Taylor Wilson, a 21-year-old nuclear physicist from the U.S., were the keynote speakers after Amano at the opening session. In 2009, at the age of 14, Wilson became the star attraction of the nuclear community when he worked with nuclear fusion. Since then, he has developed several innovations in the field of nuclear energy. He directs several academic laboratories for fundamental and applied research in nuclear science.

Uses of graphene

Wilson drew the attention of the delegates to the production of graphene, a material made up of a single layer of carbon atoms that conducts electricity with very low resistance. Graphene is, therefore, of great interest to many industries, especially cell phone manufacturers. Production of graphene and its use in the industry were in the realm of possibility with minimal chemical additives and at low cost, thanks to the use of electron beam accelerators, he said. Wilson added: “It is incredibly environmentally friendly, and also faster and cheaper than any other technology. That is what nuclear technology allows you to do.”

Kirienko promised the delegates that Russia was “ready to expand the delivery” of medical isotopes “to all those countries requiring assistance”. This was to ward off shortages, he said.

Sinha showcased India’s sewage sludge hygienisation plant that has been operating from 1994 in Vadodara, Gujarat. It is called the Sludge Hygienisation Research Irradiator (SHRI), and in it the pathogens in municipal sewage sludge are inactivated by gamma radiation emitted from a cobalt-60 source. The resultant dry sludge is used in agriculture to supply nutrients to crops, improve soil properties and increase organic matter in the soil. Other 100-tonne a day dry sludge irradiation facilities are to come up in Ahmedabad and Nagpur. As the BARC booklet entitled “Radiation Hygienisation of Municipal Dry Sewage Sludge for Agriculture Applications” says, disposal of municipal sewage sludge in large cities is a serious problem because the sludge contains a high load of potentially infectious microorganisms, which can be a serious threat to public health.

Present sludge disposal methods have their limitations. Disposal into the sea is site specific. Incineration consumes a lot of electricity. Landfilling is not possible because of a paucity of land in urban areas. However, ionising radiation emitted by cobalt-60 can inactivate the pathogens in the sludge.

In India, radioisotopes are produced in the research reactor in Trombay, Mumbai, called Dhruva and in the Pressurised Heavy Water Reactors (220 MWe) in Rawatbhatta, Rajasthan. There are 18 commercial irradiation plants in different parts of India for the irradiation of mangoes, fish, potatoes, onions, spices, and so on. Three plants belong to the DAE; the rest are in the private sector, said G. Ganesh, chief executive of BRIT. Six more irradiation facilities are under construction.

The Scientific Forum revealed how African countries such as Ghana, Nigeria, South Africa, Sudan and Tunisia were increasingly embracing nuclear technologies to treat cancer patients, sterilise medical products, manufacture hydrogel and increase production from oil wells. Mahama Ayariga, Ghana’s Minister for Environment, Science, Technology and Innovation, said radiation technology was used in his country in many sectors from medicine to agriculture. “We have seen how greatly these techniques benefit various industries,” said Ayariga, who holds a master’s degree in law from Harvard University. The Ghana Atomic Energy Commission provides cobalt-60 irradiation services to hospitals and companies for the irradiation of syringe needles, sutures, gauze, surgical clothing, scalpels, scissors, and so on. Ghana provides other African countries with irradiation services and training.

Amano praised the growing interest in Africa in peaceful uses of nuclear energy. He noted in his statement on September 14 to the IAEA General Conference: “The agency’s assistance to countries that are considering starting or expanding nuclear power programmes is delivering tangible results. This year, two Integrated Nuclear Infrastructure Review Missions took place in Kenya and Nigeria. A third one is scheduled in Morocco next month. This reflects the growing interest in peaceful nuclear technology in Africa.”

The multiple uses of NDT technology and electron beams dominated the proceedings in the Scientific Forum. “The NDT is a billion-dollar business,” said Abdul Nassir Bin Ibrahim, president of the Malaysian Society for NDT and managing director of the Madani NDT Training Centre. Oil/gas production platforms, processing facilities and pipelines entail a lot of welding. If a weld has defects or improper fusion or lacks penetration, it could lead to accidents, such as the Bhopal gas leak catastrophe in December 1984, the Oklahoma gas pipeline explosion in October 2013 and the TransCanada gas pipeline explosion in September 2015. “A method has to be invented to trace them [the defects in welds]. That is where the NDT comes in,” Ibrahim said. Nuclear technology-based NDT detects cracks and shows them in a two-dimensional pictorial form. Personnel trained in NDT technology can find out what has happened inside a weld. “On the basis of this, technicians have to make decisions whether millions of dollars worth of equipment can be operated safely,” he added.

Just as radiation-based imaging techniques such as C.T. scans and positron emission tomography are used in medical diagnostics, imaging techniques based on similar principles were now applied in the industrial diagnostic domain, said Umesh Kumar, Head of the Industrial Tomography and Instrumentation Section at BARC. “BARC has developed advanced computed industrial tomography, which provides not only dimensional information but also material characteristics without distorting the integrity of the object. Emission tomography can be used to characterise containers/drums having nuclear waste, to check the integrity of pipes for cracks, and so on,” Umesh Kumar said.

In an interview to Aleksandra Peeva of the IAEA Office of Public Information and Communication, published on the IAEA website on September 9, Wilson said: “Radioactivity and ionising radiation hold a special place in the cultural psyche, really unlike any other technology or field. Most of this mystery comes from a lack of understanding of the way in which these invisible forces and processes work, outside of traditional images of mushroom clouds and hyperbolic cooling towers.

“Certainly nuclear technologies have more than their fair share of dangers, which most people are familiar with, but all technology is not created equal, and most are unaware that nuclear techniques in medicine save countless lives every year, that radiation processing techniques prevent the use of environmentally harmful chemicals, and that nuclear power represents one of the most important power sources for reducing society’s [carbon] emissions from the production of electricity.”