Bariblock for shielding the TRIGA MARK II nuclear reactor channel
The Bariblock barytic block, thanks to its reduced thickness, has been chosen to create a modular shielding against ionizing radiation coming from a channel of the nuclear research reactor TRIGA MARK II of the University of Pavia.
In the Laboratory of Applied Nuclear Energy L.E.N.A. of the University of Pavia is in service the TRIGA MARK II, a reactor for nuclear fission research.
The reactor is equipped with several radiation channels inside and outside the reactor core. Bariblock has been chosen to shield the B channel, the one with the highest percentage of thermal neutrons on the total and the lowest fast flux, modified to apply the PGNAA (Prompt Neutron Activation Analysis) technique on samples belonging to the cultural heritage category (works of art, archaeological finds, etc…). This type of analysis allows to obtain both quantitative and qualitative information on the elementary content of a given sample without the need to take parts of it and/or destroy it. In order to allow the personnel in charge to work safely, as required by current regulations in terms of radiation protection, it was necessary to create a shielded radiation channel, equipped with a labyrinth and a passage wide enough to allow the correct positioning of samples in the order of tens of cm. The choice was to make the channel in barytic concrete given the low costs and lower overall thickness compared to traditional concrete with the same shielding effect.