New Irradiation Device at the Budapest Research Reactor

In close cooperation with the Paul Scherer Institute (Switzerland) two new rigs called BAGIRA (Budapest Advanced Gas cooled Irradiation Rig with aluminium structure) have been built. The irradiation volume of the largest rig is 360 x 20 x 30 mm and it can operate in the temperature range of 150-650oC. The heating is combined gamma and electrical heating; the temperature measurement is performed by 6 thermocouples, and controlled by a helium-nitrogen gas mix flow. The neutron flux within the rig is about 2-6 x 1013 n.cm-2s-1. Similar but smaller irradiation channel have been built for long term irradiations at lower temperature for testing the materials of the fusion reactor. Altogether 24 different irradiations have been performed until now studying the radiation resistance of RPV steels, model alloys, titanium and tungsten, aluminium alloys and ceramics. In 2010 the irradiation facilities of the BRR were under upgrade again. The purpose of the modernisation was to satisfy the requirements at the development and testing of materials for the third and fourth generation reactors, fusion devices and advanced testing of presently used materials. The new irradiation rig is: i) Shielded from the thermal neutrons by boron carbide shield (better fast/thermal neutron ratio, less gamma heat generation, less activation of the samples); ii) The temperature range of the operation is increased up to 600oC; iii) The minimum stable operation temperature is as low as 100oC; iv) The target can be rotated during irradiation to avoid self-shield; v) The temperature control became to electric resistance heating in 6 zones instead of the present 3 zones; vi) The sample removal after irradiation simplified and the personal dose during sample removal will be reduced; vii) The mass of the activated structure also reduced and also the preparation costs of a new irradiation reduced; viii) Further new feature of the design is the in-pile creep and low cycle fatigue test on small size specimens. (author)