Neutron irradiation effects on mechanical properties of ITER specification tungsten

In this contribution, we present the results of recent neutron irradiation campaign performed in the material test reactor BR2 (Belgium) on pure tungsten. We have applied various irradiation conditions and sample geometry to assess the effect of neutron irradiation on hardness, bending, tensile and fracture mechanical properties. The investigated material is a commercially pure tungsten plate fabricated according to the international thermonuclear experimental reactor (ITER) specification for the application in the divertor plasma-facing components. The neutron irradiation covers a large span of temperatures and damage doses, ranging from 600 to 1200 °C and 0.1–1 dpa. The obtained mechanical properties were analyzed to deduce the shift of the ductile to brittle transition temperature (DBTT) applying bending, tensile and fracture toughness-testing procedures. Then, a correlation of the fracture toughness with the change of the hardness was established. The obtained results are compared with the already published results on another ITER specification grade produced in the form of a rod. The presented and discussed results show that the performance of the compared grades in terms of the irradiation-induced embrittlement is similar, and that the irradiation in the high-temperature region (600–800 °C) causes a considerable DBTT shift already at 0.2–0.5 dpa.