Irradiation devices and irradiation programmes at the high flux reactor (HFR) Petten for the investigation of the irradiation behaviour of stainless steels

Abstract

Irradiation testing of stainless steels represents an important share in the utilization spectrum of the high flux reactor (HFR) Petten. These tests address in particular austenitic and martensitic steels for thermo-nuclear fusion reactors, austenitic steels for fast breeder reactors, and stainless steels and CrNi-alloys for light water reactors. A number of well-proven irradiation devices covering an extensive range of applications and operated by a vastly experienced group are available at the HFR. In addition, at the Petten hot cells, many diversified tools exist for irradiation testing of stainless steel. The irradiation devices are tailored to provide typical, reactor specific environment conditions to the samples. Such conditions are maintained within narrow specifications. In this respect, the long lasting operational experience originating from the many materials irradiation programmes performed at the HFR, the high and consistent availability of the HFR and its reliability with regard to provision of predictable and reproducible irradiation conditions, are the keys to these many demonstrable experiments. The adjustment of typical neutron spectrum at the irradiation samples is performed through an appropriate choice of structural materials and their arrangement within the irradiation device. Many irradiation devices are reloadable, being specially suited for intermediate unloading and hot cell measurement of the irradiated samples. Other devices are equipped with integral loading and measuring systems for in-pile measurement of characteristic irradiation parameters (e.g. the creep behaviour). The neutron fluence is calculated and then measured after irradiation from neutron fluence monitor sets which are integrated into the sample carriers. The post irradiation examination and testing of the irradiated samples is performed either at the customer's hot cells or at the Petten hot cells, in particular, when intermediate measurements are required. Dedicated and specialized testing equipment for tensile, creep, Charpy, fatigue and crack propagation testing, various microscopy systems (SEM, TEM) and other test equipment (gamma-scanning, chemical analysis, image analysis, etc.) are all available at the Petten hot cells.