An activation product is a material that has been made radioactive by the process of neutron activation.

Process

Fission products and actinides produced by neutron absorption of nuclear fuel itself are normally referred to by those specific names, and activation product reserved for products of neutron capture by other materials, such as structural components of the nuclear reactor or nuclear bomb, the reactor coolant, control rods or other neutron poisons, or materials in the environment. In these cases their production is undesired and they need to be handled as radioactive waste. Some nuclides can be produced both as activation products or as fission products. For example molybdenum-99 which is an important nuclide in "molybdenum cows" used in medical diagnostics can be produced either by fissioning ²³⁵U or by neutron irradiation of ⁹⁸Mo.^[1]

Practical uses

However, neutron activation (usually in a dedicated research reactor, but sometimes also in power reactors like the CANDUs at Bruce nuclear generating station^[2][3][4]) is also used deliberately to produce desired radioisotopes for uses in food irradiation, nuclear medicine and to sterilize equipment via gamma radiation emitted from isotopes such as Cobalt-60.^[5]

Activation products in a reactor's primary coolant loop are a main reason reactors use a chain of two or even three coolant loops linked by heat exchangers.

Fusion reactors will not produce radioactive waste from the fusion product nuclei themselves, which are normally just helium-4, but generate high neutron fluxes, so activation products are a particular concern.

List of activation products

Activation product radionuclides include:

[1] Branching fractions from LNHB database.

[2] Branching fractions renormalised to sum to 1.0..

References

External links

• Handbook on Nuclear Activation Cross-Sections, IAEA, 1974
• Nuclear Structure and Decay Databases (nndc.bnl.gov) Archived 2013-03-20 at the Wayback Machine
• New and revised half-life measurements results made by the Radioactivity Group of NIST
• HANDBOOK OF NUCLEAR DATA FOR SAFEGUARDS: DATABASE EXTENSIONS, AUGUST 2008