In-situ gamma spectrometry measurements of time-dependent Xenon-135 inventory in the TRIGA Mark II reactor Vienna

摘要

In this work, it has been shown that the time dependent Xe-135 inventory inthe TRIGA Mark II reactor in Vienna, Austria can be measured via gammaspectrometry even in the presence of strong background radiation. It isfocussing on the measurement of (but not limited to) the nuclide Xe-135. The time dependent Xe-135 inventory of the TRIGA Mark II reactor Vienna hasbeen measured using a temporary beam line between one fuel element of the coreplaced onto the thermal column after shutdown and a detector system locatedjust above the water surface of the reactor tank. For the duration of one week,multiple gamma ray spectra were recorded automatically, starting each afternoonafter reactor shutdown until the next morning. One measurement series has beenrecorded over the weekend. The Xe-135 peaks were extracted from a total of 1227 recorded spectra usingan automated peak search algorithm and analyzed for their time-dependentproperties. Although the background gamma radiation present in the core aftershutdown was large especially in the lower energy range, the Xe-135 peaklocated at 249.8 keV could be extracted from the most spectra where present andcould be compared to theoretical calculations.