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Decay heat is the heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms. Decay heat occurs naturally from decay of long-lived radioisotopes that are primordially present from the Earth's formation.
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered radioactive. Three of the most common types of decay are alpha, beta, and gamma decay.
The flow of heat from Earth's interior to the surface is estimated at 47±2 terawatts (TW) [1] and comes from two main sources in roughly equal amounts: the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of Earth. [2]
The theory of BBN gives a detailed mathematical description of the production of the light "elements" deuterium, helium-3, helium-4, and lithium-7. Specifically, the theory yields precise quantitative predictions for the mixture of these elements, that is, the primordial abundances at the end of the big-bang.
The decay energy is the mass difference Δm between the parent and the daughter atom and particles. It is equal to the energy of radiation E . If A is the radioactive activity , i.e. the number of transforming atoms per time, M the molar mass, then the radiation power P is:
The amounts of total mass in elements heavier than hydrogen and helium (called 'metals' by astrophysicists) remains small (few percent), so that the universe still has approximately the same composition. Stars fuse light elements to heavier ones in their cores, giving off energy in the process known as stellar nucleosynthesis.
This is a list of radioactive nuclides (sometimes also called isotopes), ordered by half-life from shortest to longest, in seconds, minutes, hours, days and years. Current methods make it difficult to measure half-lives between approximately 10 −19 and 10 −10 seconds.
These use heat produced by radioactive decay of strontium-90 to generate heat, which can be converted to electricity using a thermocouple. Strontium-90 has a shorter half-life, produces less power, and requires more shielding than plutonium-238 , but is cheaper as it is a fission product and is present in a high concentration in nuclear waste ...