Improvements on decay heat summation calculations by means of total absorption gamma-ray spectroscopy measurements

The decay heatof fission productsplays an important role in predictions of the heat released by nuclear fuelin reactors. In this contribution we present results of the analysis of the measurement of the beta decayof some refractory isotopes that were considered possible important contributors to the decay heatin reactors. The measurements presented here were performed at the IGISOL facility of the University of Jyvaeskylae, Finland. In our measurements we have combined for the first time a Penning trap(JYFLTRAP), which was used as a high resolution isobaricseparator, with a total absorption spectrometer. The results of the measurements as well as their consequences for decay heatsummation calculations are discussed.