Book excerpt: The fission product inventory and the decay heat associated with driver fuel irradiated to goal exposure (45,000 MWd per metric ton) in the Fast Test Reactor is presented, based on calculations using the computer code RIBD with a nuclear data library prepared for the FTR environment. Curie inventories as a function of decay time are given for each of about 350 isotopes or isomeric states generated by the fast-neutron induced fission of either 239Pu or 238U, by down-chain decay, or by subsequent neutron capture. Beta, gamma, and total decay power are given in percent of operating power for decay times from 1 sec to about 10 years. Uncertainty in the decay heat calculations, based on propagation of the uncertainties associated with input nuclear data, is estimated. The uncertainty is calculated to be less than +̲ 10% for the first 10 days, and less than +̲ 20% over a 10-yr decay period.