For the regular person, the term “nuclear sciences” might either conjure up vivid images of horrific nuclear bomb detonations or ominous-looking nuclear power plants. However, nuclear sciences offer more than just destruction or an oft-misunderstood source of energy. Professor Syed M. Qaim from the Research Centre Jülich and University of Cologne, Germany arrived on Malaysia shores to provide a clear view of the numerous benefits nuclear sciences have to offer.
Universiti Putra Malaysia (UPM) and the Academy of Sciences Malaysia co-organised the lecture featuring Professor Qaim on 7 February 2020. Professor Qaim’s lecture sets out to survey the achievements, potentials and limitations of nuclear sciences that are relevant to peaceful applications. His lecture would show that nuclear sciences can be beneficial to the basic requirements of mankind.
Food and Agriculture
First, Professor Qaim touched upon the topic of applying nuclear sciences in food and agriculture. Professor Qaim elaborated on the techniques used in relation to nuclear sciences. The most commonly heard application is food irradiation, the application of ionizing radiation to food) to make food safer for consumers and extends the shelf life of foods by reducing or eliminating microorganisms and insects.
Another nuclear technique used in food and agriculture is the sterile insect technique (SIT). Developed under the Joint Food and Agriculture Organisation (FAO) and International Atomic Energy Agency (IAEA) Programme, this environment-friendly method involves the mass-rearing and sterilisation, using radiation, of a target pest, followed by the systematic area-wide release of the sterile males by air over defined areas. These sterilised insects will then mate with wild females resulting in no offspring and a declining pest population.
Nuclear sciences are also used in tracer studies of the behaviour of agrochemicals. Radioactive or stable isotopes (“radiotracers”) are widely used for basic studies of the behaviour and significance of pesticide residues that may find their way into food, environment and living organisms.
Mankind also benefits from using nuclear techniques in understanding plant physiological functions. Professor Qaim provided examples, such as studying carbon dioxide uptake by leaves, transport of photosynthates towards plant roots, as well as studying nitrogen fixation in plant roots.
Next, Professor Qaim elaborated on nuclear methods used in protecting the environment. He stated that nuclear methods such as neutron activation and radiometric analyses are used in analysis of heavy elements, industrial pollutants and long-lived radioactivity.
Nuclear power as a source of clean energy was also mentioned by Professor Qaim. Contrary to popular belief, nuclear energy is a relatively clean and safe energy source, utilising a process called nuclear fission. Nuclear fission is the process behind this clean source of energy, producing large amounts of energy while releasing negligible levels of carbon dioxide.
Another application of nuclear sciences in environmental protection involves using radioisotopes such as carbon-14 in the modelling of geophysical, geological and atmospheric phenomena. The carbon-14 (radioisotope of carbon) in an object containing organic material is measured to determine its age.
Health and Medicine
Radioactivity has become an integral part of medicine, a branch called nuclear medicine. Professor Qaim elaborated on the application of external radiation therapy to treat malignant tumours. External radiation therapy delivers high-energy X-rays or electron beams to a patient’s tumour. This method destroys cancer cells while sparing surrounding normal tissues. Additionally, the therapy can also be used to relieve symptoms in patients with advanced cancer or cancer that has metastasised (spread to other parts of the body).
Nuclear applications in medicine also extends to treatment of deep-lying tumours with methods like nuclear-charged particle therapy or endoradiotherapy. Nuclear-charged particle therapy or hadron therapy is a form of cancer radiotherapy based on charged nuclear particles (protons and light ions) for treatment of early and advanced tumors. Meanwhile, endoradiotherapy is a form of internal radiation therapy in which a radioactive substance is ingested by or injected into the patient. This form of chemotherapy is utilised to destroy small groups of cancer cells in multiple locations.
Besides that, radioactive chemicals can be used in diagnostic studies to various effects, such as identifying areas of inflammation and excess bone turnover. The radioactive chemicals emit small beams of radiation called gamma rays that can be picked up by a special camera.
Aside from real-world applications, nuclear sciences are also applied in fundamental research, to gain understanding of properties of elements with atomic numbers exceeding 103. This endeavour serves to explain the effects of relativity on atomic electrons as well as to continue building upon the periodic table. However, such endeavour comes with its own host of challenges.
Professor Qaim stated several of these challenges, such as a very low production cross section (probability that two particles will collide and react in a certain way); a very short half-life (usually in the order of seconds) due to the low stability of elements; competing fission processes resulting in high matrix activities; production of a very small amount of product nuclide available for research; relativistic effects (discrepancies between values calculated by models that consider and that do not consider relativity); and the unpredictability of the element’s chemistry.