Tracers are substances with atomic or nuclear, physical, chemical or biological properties that can help identify, observe or follow the behaviour of various physical, chemical or biological processes. Radioactive tracers are widely used to diagnose industrial reactors, for instance by measuring the flow rate of liquids, gases and solids.
A radioactive tracer is a chemical compound in which one or more atoms have been replaced by a radioisotope. Monitoring its radioactive decay, a radiotracer can be used to explore the mechanism of chemical reactions . They are also used for flow visualisation through different technologies, such as Single Photon Emission Computed Tomography (SPECT), Positon Emission Tomography (PET) and Computed Radioactive Particle Tracking (CARPT).
Nuclear gauges have a radioactive source that is covered by a radiation blocking shield. Gauges can contain a gamma, beta or neutron radiation source. Different sources are used depending on what the nuclear gauge is measuring. Radiation from a nuclear gauge does not make the materials it measures radioactive.
About Nuclear Gauges
The use of nuclear gauges is a type of industrial radiography. Radiography is the use of radiation to produce an image on photographic film. This is similar to the way a medical x-ray uses radiation to produce images of bones.
Nuclear gauges measure three main things: thickness, density, and fill level. Thickness gauges are used in manufacturing to make sure an entire product or material is the same thickness throughout, or to make sure the coating on a material is even. Density gauges are used in cement, petroleum, and road production to make sure that the density of a material is the same. Level gauges measure how much liquid is in a container, to make sure that each container has the same amount of product.
Nuclear submarineResearch into nuclear-based propulsion of marine vessels began in the 1940s with the dawn of the “nuclear age”. Since then, only six nations have owned and operated nuclear submarines: China, France, India, Russia, the UK and the US.
Research into nuclear-based propulsion of marine vessels began in the 1940s with the dawn of the “nuclear age”. Since then, only six nations have owned and operated nuclear submarines: China, France, India, Russia, the UK and the US. Considering Australia has just torn up a A$90 billion contract to construct a new arsenal of conventional submarines, yesterday’s announcement will probably come as a surprise to many.
About Nuclear Submarines and Aircraft Carriers
In 1954, the Navy launched the first submarine that used radioactive material as a power source. Its name was the USS Nautilus and it was the first submarine to travel to the North Pole in 1958. Before then, submarines used diesel engines and had to go into port for fuel. Nuclear power allowed submarines to run for about twenty years without needing to refuel. Food supplies became the only limit on a nuclear submarine’s time at sea. Since then, similar technologies have been developed to power aircraft carriers.
The Australian government has just declared an historic defence agreement with the United States and United Kingdom that will see a new fleet of nuclear-powered submarines patrol our shores and surrounding waters.
Research into nuclear-based propulsion of marine vessels began in the 1940s with the dawn of the “nuclear age”. Since then, only six nations have owned and operated nuclear submarines: China, France, India, Russia, the UK and the US.
Considering Australia has just torn up a A$90 billion contract to construct a new arsenal of conventional submarines, yesterday’s announcement will probably come as a surprise to many.
Thermonuclear weaponthermonuclear bomb, also called hydrogen bomb, or H-bomb, weapon whose enormous explosive power results from an uncontrolled self-sustaining chain reaction in which isotopes of hydrogen combine under extremely high temperatures to form helium in a process known as nuclear fusion. The high temperatures that are required for the reaction are produced by the detonation of an atomic bomb.
Manhattan ProjectThe Manhattan Project was the code name for the American-led effort to develop a functional atomic weapon during World War II. The controversial creation and eventual use of the atomic bomb engaged some of the world’s leading scientific minds, as well as the U.S. military—and most of the work was done in Los Alamos, New Mexico, not the borough of New York City for which it was originally named. The Manhattan Project was started in response to fears that German scientists had been working on a weapon using nuclear technology since the 1930s—and that Adolf Hitler was prepared to use it.
Nuclear propulsionNuclear electric propulsion systems use propellants much more efficiently than chemical rockets but provide a low amount of thrust. They use a reactor to generate electricity that positively charges gas propellants like xenon or krypton, pushing the ions out through a thruster, which drives the spacecraft forward. Using low thrust efficiently, nuclear electric propulsion systems accelerate spacecraft for extended periods and can propel a Mars mission for a fraction of the propellant of high thrust systems.
Radioactive wasteRadioactive waste is broadly classified into low-level waste (LLW), such as paper, rags, tools, clothing, which contain small amounts of mostly short-lived radioactivity, intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding, and high-level waste (HLW), which is highly radioactive and hot due to decay heat, so requires cooling and shielding.
Hybrid nuclear fusion–fission (hybrid nuclear power) is a proposed means of generating power by use of a combination of nuclear fusion and fission processes.
Nuclear fusionNuclear Fusion is the acknowledged world-leading journal specializing in fusion. The journal covers all aspects of research, theoretical and practical, relevant to controlled thermonuclear fusion.
Nuclear fusion is a reaction through which two or more light nuclei collide to form a heavier nucleus. The nuclear fusion process occurs in elements that have a low atomic number, such as hydrogen. Nuclear Fusion is the opposite of nuclear fission reaction in which heavy elements diffuse and form lighter elements. Both nuclear fusion and fission produce a massive amount of energy.
Nuclear fuelNuclear fuel is the fuel that is used in a nuclear reactor to sustain a nuclear chain reaction. These fuels are fissile, and the most common nuclear fuels are the radioactive metals uranium-235 and plutonium-239. All processes involved in obtaining, refining, and using this fuel make up a cycle known as the nuclear fuel cycle.
The nuclear fuel cycle consists of front-end steps that prepare uranium for use in nuclear reactors and back-end steps to safely manage, prepare, and dispose of used—or spent—but still highly radioactive spent nuclear fuel.
Uranium-235 is used as a fuel in different concentrations. Some reactors, such as the CANDU reactor, can use natural uranium with uranium-235 concentrations of only 0.7%, while other reactors require the uranium to be slightly enriched to levels of 3% to 5%. Plutonium-239 is produced and used in reactors (specifically fast breeder reactors) that contain significant amounts of uranium-238. It can also be recycled and used as a fuel in thermal reactors. Current research is being done to investigate how thorium-232 can be used as a fuel.
UUranium is the most widely used fuel by nuclear power plants for nuclear fission. Nuclear power plants use a certain type of uranium—U-235—as fuel because its atoms are easily split apart. Although uranium is about 100 times more common than silver, U-235 is relatively rare at just over 0.7% of natural uranium. Uranium concentrate is separated from uranium ore at uranium mills or from a slurry at in-situ leaching facilities. It is then processed in conversion and enrichment facilities, which increases the level of U-235 to 3%–5% for commercial nuclear reactors, and made into reactor fuel pellets and fuel rods in reactor fuel fabrication plants.
Nuclear fuel is loaded into reactors and used until the fuel assemblies become highly radioactive and must be removed for temporary storage and eventual disposal. Chemical processing of spent fuel material to recover any remaining product that could undergo fission again in a new fuel assembly is technically feasible, but it is not permitted in the United States.
