Measurements of decay heat of spent nuclear fuel

The project Measurements of decay heat of spent nuclear fuel and other parameters of used nuclear fuel using non-destructive radiation detection overlaps with the other project Non-destructive assay techniques for safeguards verification of nuclear fuel, using many of the same techniques.

When nuclear fuel is removed from a reactor where it has been used, the decay of the radioactive fission products will still produce heat. While there is a strong safeguards perspective in the control of various parameters of nuclear fuel, the measurement of the remaining decay heat is mostly of interest in the preparation for final storage. Before the fuel can be placed in the final underground repository it must have lost enough of its decay heat in order not to have deteriorating effects on the encapsulation materials.

The various methods for measuring decay heat and other parameters include, among others, gamma tomography and gamma-ray spectroscopy, viewing of Cherenkov light and gamma scanning.