The waste stream from PUREX reprocessing contains most of the radioactive fission products
in the spent fuel, along with small quantities of unextracted uranium and plutonium.
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.
The MELCOR decay heat package models the decay heat power resulting from the radioactive decay of fission products
Evaluation of amaranth components and research of the polysaccharide component fermentation to fractional fission products
, UTB Zlin 2004.
The workshop concluded that the potential of current fusion technology to utilize the actinides for generating energy and destroying long-lived fission products
calls for a greater international effort in the area of fusion driven sub-critical systems
If this spent fuel is reprocessed to recover plutonium, these fission products
are concentrated to become high-level waste.
This technology allows the "breaking up" or "burning" of highly radioactive fission products
to reduce their toxicity and their life cycle, which can be hundreds of thousands of years.
For example, PBMR power systems will require making millions of spherical fuel elements a year to the exceedingly high and uniform quality levels needed to ensure that radioactive fission products
are retained in the fuel.
ATW systems are designed to destroy long-lived fission products
, reducing the time required for the waste to decay naturally from 10,000 to less than 1,000 years.
But its reprocessing becomes difficult because of increases in fission products
at high-temperature burning.
The criticality event tends to scatter the fissile material and fission products
in the area of the accident, and the dispersal of the fissile material normally prevents a prolonged chain reaction.
Inside these, spent nuclear fuel or solid uranium and fission products
would be stacked like poker chips within metal tubes.