Surveillance test of OWL-2 inpile tube

A series of irradiation surveillance tests performed in integrity evaluation of an inpile tube for the test loop OWL-2 are described. Specimens were exposed to the neutron fluences from 1 x 1020 to 3.4 x 1021 n/cm2 (>1 MeV), and subjected to post-irradiation tensile test at room temperature and service temperature 285 0C. The strength increased and the ductility decreased with increasing neutron fluence. The reduction in fracture ductility due to neutron irradiation in the fluence range was insignificant, and the elongation of 33% was retained even for the maximum neutron fluence at 2850C. Little decrease of the ductility with fluence indicates that the tube would be in service for long time, ie to the integral fluence of 3.4 x 1021 n/cm2. (auth.)