[en] The Zr-2.5Nb alloy is used in the manufacture of pressure tubes for the CANDU nuclear power reactors. These tubes are subjected to severe service conditions: one o f them, the heavy water corrosion due to the coolant generates release of hydrogen, part of which ingress in the material raising its initial concentration and exposing them to a phenomena referred as delay hydrogen cracking. The results presented in this paper show the performance of a pressure tube of domestic manufacture under conditions of tension and hydrogen content in order to be compared with the behavior of a standard pressure tube in operation in the nuclear power plant. To do this is, cantilever notched and pre cracked samples were hydrided from both kinds of tubes. Each one of these samples was subjected to the cantilever beam test, which consists in a bending test performed in a furnace at 250^oC. Starting from a stress intensity factor Ki which determines the propagation start of the crack, the growth is followed by the acoustic emission technique up to the arrest of the crack by controlling the bending load. This work presents the comparative data such as critical voltages, behavior of hydrides, and DHC parameters from both trials. Although the number of tests is reduced; results show a good performance of the tubes of domestic manufacture (author)

[en] In relation CAREM 25 project, PPFAE, CNEA, has been fabricated pods for fuel rods for that reactor. They were used the same fuel rods that to be irradiate and evaluate their behavior with that the same Uranium pellets. The scope of the agreement signed between the authorities of the CNEA and Institutt for Energiteknikk (IFE) in Norway, it contemplated irradiated fuel rods type CAREM fabricated from these fuel pods in the OECD Halden Reactor Project (HRP, venture led by IFE and integrate more than 16 countries). The work contemplates the production of two experimental item fuel pods. From the second item fuel pods will be used in the fuel rods. In this paper we analyze the sequences used; the results obtained and the general conditions for the development of the final process to be applied in the production phase for a reactor CAREM 25 (author)

[en] The Life Extension Program for the PHWR Embalse power reactor of Argentina includes the replacement of de original set of 2,5% Nb pressure tubes by a new one It was also decided to made the new set de pressure tubes locally from imported Zr-2,5% Nb extruded tubes. Based on the degraded processes that develop in service a new set of metallurgical requirements was set by the Designer to be follow for new suppliers. As the mechanical properties of pressure tubes in operation depend on the micro-structural deformation, it is necessary to add to the normal macroscopic quality control same additional mechanical and microstructural studies, especially during the development stage. In the present paper the current status of delay hydrogen cracking, full width at half maximum (FWHM) of x-ray diffraction peaks, alpha phase thickness log-normal distributions and Kearns texture factors are summarized to estimate the magnitude of the micro-structural characteristics of pressure tubes obtained from imported Zr-2,5% Nb extruded tubes that were processes following designer specifications. The pressure tubes were obtained by two step of plastic deformation in a HPTR 60-120 tube rolling machine without intermediate annealing and a final thermal treatment (author)