MadSci Network: Physics |
Spent nuclear fuel already contains several fission products that are prolific neutron sources. For example, Cm-244 and Cm-242 are typically the dominant neutron-emitting isotopes in spent nuclear fuel. These isotopes have spontaneous fission half lives of 18.1 and 0.45 years respectively. In addition to isotopes such as these that spontaneously fission, there is a high neutron output from (alpha,n) reactions. For Cm-242 the rate of alpha decay is around 10E+12 alphas/sec per gram of the isotope. This then results in the production of around 10E+6 neutrons per second. So as you can see there are already abundant sources of neutrons in the spent fuel. It is highly unlikey that it would economical to process the fuel assemblies for the purpose of adding additional neutron sources to those already present. Currently nuclear fuel is considered to be a rather inexpensive part of producing energy from nuclear power. Also, to add a neutron source that would have a significant effect on core reactivity, would require a source on the same order of magnitude or larger than that already present. Inserting a neutron source this large into the core, would raise series safety issues in addition to the economic issues Construction of a "neutron source" rod would probably be relatively straight forward, but the economic and licensing issues would likely be very difficult.
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