Nuclear energy is ubiquitous in our day to day. We find it in smoke detectors in our homes, in customs controls, in food, in industry, in transportation, in the environment and, of course, in medicine, the field where perhaps we most recognize its presence. In fact, it could be said that we are submerged in a large natural radioactive pool. Between two beats of the heart, 8,000 to 10,000 atomic nuclei disintegrate in our body. Every hour, about 30,000 disappear in our lungs simply due to the presence of radioactive isotopes in the air we breathe. Due to the food we eat, about 15 million nuclei of potassium-40 (40K) and about 7,000 of natural uranium disintegrate in our stomach and intestines.
To all this should be added the more than 200 million gamma rays from the soil and construction materials that pass through us every hour, and the several hundred thousand secondary cosmic rays, a by-product of the interaction of radiation and particles. subatomics emitted by black holes, active galaxies or supernova explosions with atoms in the upper atmosphere.
We are surrounded by nuclear energy, and we use it in many different ways every day. Next, we are going to review some of them.
1. Get energy
The indiscriminate use of fossil fuels emits waste into the environment that has caused anthropogenic climate change, as confirmed by a very broad scientific consensus. For this reason, the need for an energy transition towards renewable energies is increasingly urgent. For many scientists, nuclear energy has to back up this transition.
In Spain, the percentage of energy sources today is approximately 40% fossil, 40% renewable and 20% nuclear. Many experts believe that, if nuclear power plants are closed today, the alternative would not be renewables; that 20% would fall on natural gas, which has high CO2 emissions, and makes the price of electricity more expensive.
2. Employ more efficient agriculture
In principle, it is difficult to imagine that radiation is used for something that, in the end, we are going to take to our mouths, but it is like that. For example, thanks to the use of certain radioactive tracers, such as nitrogen-15 (15N) or phosphorus-32 (32P), the minimum amount of fertilizer required for agricultural uses can be determined and thus reduce costs and its ecological impact.
3. Preserve food
Radiation also helps us to better preserve food, more or less as it happens when we heat it, refrigerate it, freeze it or treat it with chemical products, with the exception that with it we will not alter its temperature or leave residues. Around 30% of the food produced around the world is lost because it spoils before reaching our plate, something especially common in hot and humid countries. Microorganisms are largely responsible. But if we expose them to a powerful beam of gamma rays in a controlled way , we can prevent them from proliferating. If you feel a certain reluctance to eat irradiated food, think that, among many other things, practically all the spices that we buy in supermarkets have been . What’s more, astronauts’ food is preserved in this way.
4. Get more variety of plants
Thanks to atomic physics it is also possible to obtain more varieties of plants. We know that species change because mutations occur in their DNA. As we mentioned, these, to a large extent, are due to the natural radioactivity that surrounds us. Why not do the same, but in a controlled way? By knowing which mutations to cause, it is possible to genetically improve plants. In the last decades, some 3,200 new varieties have been developed in this way and sorghum, garlic, wheat, bananas, beans or peppers have been better resistant to pests and adapt more easily to climatic conditions. adverse.
5. Keep pests under control
Nuclear technology also allows us to keep pests under control. About 10% of world agricultural production is lost due to different species of insects. As we cannot overuse chemical pesticides to deal with them, alternative strategies have been developed.
One of them is the so-called sterile insect technique (SIT). In essence, this consists of raising a large number of male specimens that are sterilized through the use of radiation and then introduced into their natural environment. They remain sexually competitive, but do not produce offspring, causing the populations to be reduced plummeting.
In 1998, for example, nuclear power was used to stop a borer invasion in Libya. The larvae of these insects can be very dangerous to cattle, as the females lay eggs in their soft tissues, through open wounds or holes, and the worms, once hatched, burrow into the meat. This causes infections that, in turn, attract more females. The rapid international response and the use of the SIT prevented the crisis from spreading to the Mediterranean basin and Africa.
6. Make medical diagnoses
Where radioactive tracers are especially useful is in medicine. Proof of this is that five Nobel laureates have been related to it. In the developed world, approximately 1 person in 50 uses nuclear medicine once a year to obtain a diagnosis.
The global market for medical radioisotopes could reach € 15 billion in 2021. Some imaging techniques use radiopharmaceuticals that emit gamma rays from inside the body. The most widely used radioisotope in these cases is the nuclear isomer of technetium 99mTc. This has a half-life of six hours and allows many processes that take place in our body to be traced with the minimum of discomfort for the patient. It is used to locate tumors and to study the heart, lungs, liver, kidneys, circulation, and blood volume or bone structures. Of course, providing this element to hospitals requires the existence of nuclear reactors, the only place where we can produce it.
7. Develop treatments
In the world 1 in 500 undergoes a therapy that depends on nuclear energy. In particular, in Spain there are about 150 specialized units. In these, some 700,000 diagnoses are made and 30,000 therapeutic applications are carried out annually. In Europe as a whole, more than 10 million procedures of this type are performed in the same period of time.
If, on the other hand, we are looking for isotopes for therapeutic purposes, we must look to another part of the periodic table. In this case, we could opt for iodine-131 (133I), which is used to treat cancer and conditions of the thyroid gland, or cobalt-60 (60Co), whose gamma emissions allow both to eliminate cancerous masses and to sterilize numerous medical products, case of disposable syringes.
In addition to these classic treatments, which date back to the mid-20th century, there are other very novel ones, such as targeted alpha therapy, which is being developed to control widespread cancers. There are currently eight approved uses in Spain : against thyroid cancer and hyperthyroidism, neuroblastoma, neuroendocrine tumors, in some type of lymphoma, in prostate cancer with bone involvement, in cancer with metastatic involvement in the liver, when the bone marrow produces too many red blood cells – what is known as polycythemia vera – and in persistent inflammatory diseases in the joint synovium.
