A thorough effort has been made to revisit and now compile as many high-quality fission decay heat experiments with complementary neutron spectra, irradiation schedules, measurement techniques and nations of origin. Simulations from theoretical fission bursts to full-day irradiations have been performed, using a variety of nuclear data combinations, Bateman solvers and their results compared with the available experiments. Good agreement between calculation and experiment (C/E) is found for total heat from the major fresh fuel components in actual LWRs, however spectroscopic partial heat and decay heat in thorium fuel cycle nuclides remains discrepant – both in C/E and C/C. For minor actinides where no experimental data was available, C/C comparisons also show substantial differences between data libraries. For already irradiated fuels no simple, authoritative experimental data seems to exist.
Detailed (spectroscopic and total) decay heat break-down by nuclide is also now routinely performed for select cooling times and fissiles, using different decay or fission yield libraries to demonstrate the precise cause of the C/E or C/C discrepancies. Given the tendency for relative agreement on total values, it is clear that many compensating effects are still present.