Determination of neutron flux distribution at 1 MWatt PUSPATI TRIGA Reactor (RTP) using activation method

Neutron flux gives an important measure during the reactor operation. Therefore, it is viable to know the flux distribution inside the reactor core from the measurement of the neutron flux mapping. Neutron flux is much more affected by the reactor power, fuel elements burn-up, control rods position and other factors. Before irradiation works done such as activation analysis, radioisotope production and samples irradiation, one needs to know about the neutron flux distribution so that the samples will be sufficiently irradiated in the reactor. In PUSPATI TRIGA Reactor (RTP), neutron flux distribution inside the reactor core was determined using activation method. Two types of gold samples, namely bare gold (Au bare) and cadmium-covered gold (Au cd) were irradiated under the same condition, about same time and approximately same mass inside the reactor core. In the reactor, these samples were undergone Au-197(n,γ)Au-198 reaction. The samples were then being cooled to reduce its radioactivity to the harmless level before detected using high purity germanium detector. The activation analyses were carried out at gamma energy of 412 keV in order to determine epithermal and thermal neutron flux. In this study, neutron flux measurements were carried out in several experimental holes facilities using Al-6061 rod that can hold 10 Au samples at a time. (Author)