Frequently Asked Questions


You can learn more from our asked questions

Nuclear energy is a form of energy released from the nucleus, the core of atoms, made up of protons and neutrons. This source of energy can be produced in two ways: fission – when nuclei of atoms split into several parts – or fusion – when nuclei fuse together.

Necsa is a state-owned public company, registered in terms of the Companies Act, (Act No. 61 of 1973).

Necsa is short for Nuclear Energy Corporation of South Africa. However, note that the acronym is written like a normal word and not in all caps.

Necsa is mandated to undertake and promote research and development (R & D) in the field of nuclear energy and radiation sciences and technology.

SAFARI-1 is a 20 Megawatt light water-cooled research reactor operated by the South African Nuclear Energy Corporation (Necsa), under the auspices of the Department of Mineral Resources Energy (DMRE).

South African Fundamental Atomic Research Installation 1


Unlike power generating reactors such as Koeberg in Cape Town, the SAFARI-1 research reactor is smaller in size (about the size of a household washing machine), operates at lower temperatures and is used primarily as a neutron source for research and production of many isotopes. The other major difference when compared with power reactors is that SAFARI-1 operates at lower water pressure (in an open pool of demineralised water) and the core is accessible for sample insertion or retrieval while the reactor is in operation. The reactor operates at shorter intervals and is shut down every four weeks to allow for maintenance, inspections and refuelling – power reactors such as Koeberg can run for about 18 months without refuelling.


The Multi-Purpose-Reactor (MPR), is a pool-type reactor with an open water surface and variable core arrangement. Its main feature is plant safety and reliability. Its power is 22MWth, cooled by light water and moderated by beryllium. It has plate type fuel elements.


Fluorochemicals are the hydrocarbons that consist of fluorine. These are the chemical compounds in which at least one hydrogen atom is replaced by fluorine. Fluorochemicals are popular in fields of medical and dental, and chemical manufacturing. It is used in plasma etching in semiconductors and light bulbs, and to produce flat display panels and plastics such as polytetrafluoroethylene (PTFE).


Fission is the nuclear process that involves the splitting of a nucleus.


For example, when a nucleus such as uranium-235 fissions, it emits neutrons. Those can hit other nearby uranium-235 atoms and cause those to fission, emitting more neutrons. This process is the fission chain reaction. This chain reaction can continue if there are enough fissile nuclei in a small enough space, and the neutrons don’t get absorbed by other materials or leak out from that space.


While the reactor is running, the vast majority of neutrons are produced by the fission of U-235 in our fuel.


Neutrons are invisible just like all forms of electromagnetic and particle radiation (except for the visible portion of the light spectrum).


Isolated neutrons have a half-life of 10.4 minutes and decay to stable hydrogen (H-1) – the neutron essentially splits into a proton and an electron. The neutrons produced in the reactor core get absorbed by fuel or core materials in fractions of a second.


Isotopes are different versions of elements. They are named using the letter abbreviation of the element and the total number of protons and neutrons in the nucleus. For example, the most common isotope of natural hydrogen has just one proton a no neutron, so it is referred to as H-1. A small amount of hydrogen (about 0.01%) has one proton one neutron, so it is referred to as H-2. Because different isotopes of the same element have the same number of protons and electrons, they behave similarly in their chemistry (they may behave slightly differently physically due to their different masses). However, different isotopes of the same element can have very different nuclear properties.


Radioactive decay is the process through which some atoms revert to a more stable nuclear configuration by emitting energy (e.g., gamma rays, electrons, alpha particles). Most elements have both radioactive and stable (non-radioactive) isotopes. When an atom decays it may become a different element, or the same element with a different number of neutrons (a different isotope of the same element). Sometimes an atom will decay into an atom that is also radioactive producing a radioactive decay chain. The rate at which an isotope undergoes radioactive decay is described by the isotope’s half-life, which is the amount of time it takes for half of any amount of that radioactive isotope to decay.


Because contamination is material stuck to a surface it can usually be removed by wiping or washing it off. When a small piece of equipment becomes contaminated it might be cleaned using a wet rag. A typical personal item that might get contaminated is the bottom of a shoe, which can have a piece of radioactive material stuck to it. This can often be removed using sticky tape, or by washing it with a brush.


Radiation is energy given off by matter in the form of rays or high-speed particles. All matter is composed of atoms. Atoms are made up of various parts; the nucleus contains minute particles called protons and neutrons, and the atom’s outer shell contains other particles called electrons. The nucleus carries a positive electrical charge, while the electrons carry a negative electrical charge. These forces within the atom work toward a strong, stable balance by getting rid of excess atomic energy (radioactivity). In that process, unstable nuclei may emit a quantity of energy, and this spontaneous emission is what we call radiation.


You can’t, without the help of a radiation detector. In addition, it is important to know what type of detector you have and the type of radiation — alpha, beta, gamma, x-ray, and/or neutron — that it can detect. Scanning an object with a typical gamma/x-ray radiation detector will not detect alpha particles.


Nuclear power plants sometimes release radioactive gases and liquids into the environment under controlled, monitored conditions to ensure that they pose no danger to the public or the environment. These releases dissipate into the atmosphere or a large water source and, therefore, are diluted to the point where it becomes difficult to measure any radioactivity. By contrast, most of an operating nuclear power plant’s direct radiation is blocked by the plant’s steel and concrete structures. The remainder dissipates in an area of controlled, uninhabited space around the plant, ensuring that it does not affect any member of the public.


Nuclear plant workers are no more radioactive than anyone else. Except in unusual circumstances, such as an accident at the plant, workers receive only minimal dose of radiation and rarely become contaminated with radiation. It is important to remember that being exposed to radiation does not make one radioactive, except in very specific circumstances.


One could think of radioactive materials as a knife. Used and stored properly, a knife can help us prepare and eat food; misused, it can cause injury and possibly death. Similarly, when handled correctly, radioactive materials have many beneficial medical, industrial, and academic uses.


Criticality means that the reactor is sustaining a constant fission chain reaction.


These are also referred to as alpha rays or alpha radiation. They are the first nuclear radiation to be discovered; they are heavier and slower compared to other types or radiation. The safety concern comes in if someone were to inhale, ingest or if a particle were to enter a wound because radioactive decay would then occur inside of the body and cells. Alpha radiation is not able to penetrate human skin. You can shield with a simple centimeter of plastic against alpha particles.


Beta radiation consists of free electrons and positrons moving at a velocity such that there is a significant change in properties. They are high-energy and high-speed electrons or positrons emitted by fission fragments. Beta radiation is hazardous because like alpha radiation it can cause ionization of living cells. However, Beta radiation has the capacity to pass through living cells. Beta particles can also spontaneously mutate into cancer when it comes into contact with DNA. Heavy clothing, thick cardboard or a think aluminum plate can protect you from beta particles.


Gamma particles are high-energy photons emitted by radioactive substances. There are other names for gamma particles such as X-ray, photos and light. Some of the lower energy forms are called ultraviolet rays, infrared rays and even radio waves!  A photon is one of the fundamental particles in nature and it plays a very important role in being involved in the interactions between electrons. Gamma rays travel at the speed of light and they can travel thousands of meters in air before spending their energy. Since the gamma radiation is very penetrating matter, it must be shielded by very dense materials, such as lead or uranium.


You can shield with a simple centimeter of plastic against alpha particles. Heavy clothing, thick cardboard or a thin aluminum plate can protect you from beta particles. Gamma rays travel at the speed of light and they can travel thousands of meters in air before spending their energy. Since the gamma radiation is very penetrating matter, it must be shielded by very dense materials, such as lead or uranium.


Radiation has many uses, but it can be dangerous if it is not managed correctly. Radiation poisoning happens when a radioactive substance gives off particles that get into a person’s body and cause harm. Different radioactive substances have different characteristics.   If so, is it always dangerous? Radiation isn’t necessarily always dangerous. It depends on its strength, type and the length of exposure. The guiding principle of radiation safety is “ALARA”. ALARA stands for “as low as reasonably achievable”. This principle means that even if it is a small dose, if receiving that dose has no direct benefit, you should try to avoid it. To do this, you can use three basic protective measures in radiation safety: time, distance, and shielding.


A Nuclear Reactor is a structure that is capable of initiating and maintaining nuclear reactions. It consists of fuel, metal cladding, the reflector, control rods, a moderator, reactor pressure vessel and structural materials. The core in the reactor includes nuclear fuel to generate heat. The reactor contains and controls nuclear chain reactions that produce heat through a physical process called fission. Fissile material can be made to undergo a controlled, self-sustaining nuclear reaction with the consequent release of energy.


Nuclear radiation is used safely for medical diagnosis and treatment, in common household products such as television, measurement gauges and smoke detectors, to produce electricity, and in basic scientific research, manufacturing, minerals exploration and agriculture.


There are other uses of nuclear technology that are very beneficial such as in agriculture, medical and the space exploration fields. There are programs to improve food sustainability assisted by nuclear and related biotechnologies. Plant mutation breeding exposes plant seeds or cuttings of a given plant to radiation, such as gamma rays, to cause mutations. The irradiated material is then cultivated to generate more plants. In the medical field they use radioactive tracers to assess bodily functions and to detect, diagnose and treat disease. There are special cameras that can detect these radioactive tracers. In space exploration, there are many instruments used to detect radiation and determine the composition of the stars or another planet’s rocks, atmosphere, and soil, among many other things.


The water is very purified. You could swim in it, however, it is not practical. The reactor pool water is city water that goes through a Reverse Osmosis system and it becomes ultra-purified and back into the reactor pool. There is no radiation at the surface of the water. Only 6-8 feet of water is needed to shield the reactor. The reactor pool is over 30 feet deep.


Drinking the water should not affect someone who maintains a healthy diet. However, there is no salt in the water so we do not recommend drinking the water on your next visit.


A pulse is a controlled extraction of control rods that causes the reactor the reactor to go prompt super critical for a short amount of time. It allows us to do experiments at really high energies however we cannot sustain that energy for a really long time as it would destroy our reactor. We would use it for experiments such as for training and lab courses.


This is due to the phenomenon known as Cherenkov Radiation. It is when a charged particle, in this case an electron, travels through the medium (water) faster than light. These fast-moving particles excite the electrons of the water molecules, they absorb energy and release it as photons (light) as they return to equilibrium. The light you see has a shorter wavelength than usual, which is why it appears blue.


They all have a dome of some sort as their containment building and so they can get rid of heat. The dome contains the reactor and the smoke stack is a way to have air get rid of the heat within confinement (steam and condensation). Our stack is tall so that gives enough draw so that it pulls the material out.


There is so much security around a reactor because so many people misunderstand the actual dangers of radiation and they are unafraid of things so keeping it out of the general public is in the best interest of everyone.


Enrico Fermi and Leo Szilard invented the nuclear reactor in the 1940’s. He had always been interested in mathematics and physics, and got an engineer-mentor as he got older. Enrico Fermi was one of the most skilled and talented physicists of all time. Enrico is considered to have invented nuclear power, along with his colleagues at the University of Chicago in 1942, by successfully demonstrating the first controlled self-sustaining nuclear chain reaction.


Nuclear reactors are used as research tools, as systems for producing radioactive isotopes, and most prominently as energy sources.


It is said that radiation has no color, no smell or taste, and that you will not feel it. However, this is not entirely true. Radiation is colorless, however, it has its own taste and its sensations. When working in the radioactive contamination zone, a metallic taste very soon appears in the mouth. Then the skin feels like you are in a bright sun.


Do they work the same way? No they do not give off radioactivity they just give off heat. Microwave ovens use electromagnetic waves that penetrate food, causing water molecules to vibrate and generate heat within the food to cook it very quickly, according to the EPA. Microwaves do not make food radioactive. But it is important to make sure microwave oven doors are sealed properly to make sure the radiation stays in the oven itself.


At the surface of a neutron star, most light is emitted in the X-ray range. In the visible range, red is emitted at about the same as blue and the other colors, so it would appear white to human eyes. However, they don’t actually have a color because they are smaller than the wavelength of visible light.


The difference between radioactivity and radiation is that radioactivity is the process by which certain elements release radiation whereas radiation is energy or “energetic particles” that are released by radioactive elements. Radioactivity is a “process” while “radiation” is a form of energy.Irradiate is to “expose” or “treat” with radiation.


Irradiation refers to the conversion of an atom, molecule or substance into an ion or ions by removing one or more electrons through the radiation that is emitted. Reactor irradiation changes the properties of alloys and materials in the core, including the fuel and the zirconium alloy rod components.


Necsa currently doesn’t provide any bursaries.


Frequently visit the Necsa website’s vacancy portal for advertised job opportunities.


Frequently visit the Necsa website’s tender portal for advertised tenders.


Radioisotopes have a wide range of applications in various fields including medicine, industry, agriculture, and research. In medicine, they are used for diagnostic imaging (such as PET scans), cancer treatment (radiotherapy), and in the production of radioactive tracers for studying biological processes. In industry, they are utilized for measuring thickness and density, detecting leaks, sterilizing medical equipment, and more. In agriculture, they are used to study plant and soil nutrition, as well as pest control. And in research, they play a crucial role in studying fundamental particles and processes in physics, chemistry, and biology.


At vero eos et accusamus et iusto odio digni goikussimos ducimus qui to bonfo blanditiis praese. Ntium voluum deleniti atque.

Melbourne, Australia
(Sat - Thursday)
(10am - 05 pm)
Shopping Cart (0 items)