New irradiation device for JSI TRIGA reactor
by Jennifer Toes (CERN), 21/12/2016
Aluminium channel liner mounted to the movable trolley (Image: Vladimir Radulović)
A new irradiation device has been installed in the TRIGA Mark II reactor at the Jožef Stefan Institute (JSI) in Slovenia as part of the work completed by Work Package 15 (WP15) within the AIDA-2020 project. WP15 developed the novel transport system to allow larger samples of up to 12cm in diameter to be irradiated in the reactor.
The new irradiation device was inserted into the reactor’s Tangential Channel which passes through the graphite reflector close to the reactor core. This means samples of a larger size will now be able to be tested in the TRIGA reactor.
Up to now, two TRIGA irradiation channels were used for irradiation testing; one in the outer ring of the reactor core and the second closer to the centre. The channels measure 31.6mm and 60mm in diameter respectively.
The JSI TRIGA reactor has already hosted 31 projects (clocking a total of of 160 irradiation hours) in the first year of AIDA-2020. The facility is not only a crucial component of this project, but also serves the high-energy physics community as a whole.
The new irradiation device is comprised of a tubular aluminium liner and neutron and gamma shields mounted to a mobile stainless steel trolley. The liner protects the interior components of the Tangential Channel, and provides a point of access for the insertion and withdrawal of samples. The neutron and gamma shields, made of 5% borated polyethylene and lead respectively, prevent radiation leaking from the reactor core into the reactor hall and provide a passage for electronic cables and coolant lines to be fed through to the sample under irradiation.
Vladimir Radulović, a researcher at JSI, said: “The main challenge in the device design was finding an acceptable compromise between neutron and gamma radiation shielding and the requirement for a passage for cable and coolant line feedthrough. It came down to finding the right quantities of the right materials in the right places.”
The new irradiation device in the JSI TRIGA reactor allows increased capabilities and more flexibility in the performance of radiation hardness testing and enables more innovative studies to be conducted which may lead to further technological and scientific developments.
The larger potential sample size means researchers who had previously been unable to make use of the TRIGA reactor for their own studies due to size restrictions will be able to access the testing facility.
The device will allow users to test samples in a neutron flux which exceeds 2x1011n cm-2 s-1. It is available for use now, further measurements to verify the neutron spectra and flux profiles will be conducted in 2017.