After about 70 years, many
fission products will have decayed away.
The fuel pellets retain most of the
fission products, while the cladding acts as a second barrier [2] to contain
fission products that escape from the pellets.
To study the effect of the spray system on in-containment
fission product scrubbing, the multistage methodology has been adopted.
But, in 1982, a Nuclear Regulatory Commission laboratory calculated a hypothetical accident where the
fission products are released into the air and remain suspended indefinitely in respirable form over the nearest highly populated areas.
Burk, "SPARC-90: A code for calculating
fission product capture in suppression pools," Tech.
The long-term release comes from radioactive
fission products in fuel elements caused by the heat up of the core after accidents and it is mainly decided by core temperature.
The detector's sensitivity depends directly on the mean charge deposited by
fission products in the gas [5].
In the Moltex design, the salt is held in vented tubes, which is possible because the
fission products form compounds a in the salt.
Driven by the decay power of the
fission products and the high temperature, the basemat concrete, which is the last barrier that prevents leakage of the radioactive products into environment in the second-generation NPPs, starts to ablate [1,2].
Depleted bundles contain small amounts of
fission products and fissile plutonium, which are dangerously radioactive.
Caesium-137, or radiocaesium, is a radioactive isotope of Caesium formed as one of the more common
fission products by the nuclear fission of Uranium-235 and other fissionable isotopes in nuclear reactors and nuclear weapons.
This radioactive nucleus, one of the
fission products resulting from the fissioning of uranium, is an effective absorber of thermal neutrons.
