No abstract available

[en] Very stringent purity specifications must be applied to low activation vanadium alloys, in order to meet recycling goals requiring low residual dose rates after 50-100 years. Following a suitable cooling period after their use, the vanadium alloy components could be melted in a controlled atmosphere to remove volatile radioisotopes. The aim of the melting and decontamination process will be the achievement of dose rates low enough for open-quotes hands-onclose quotes refabrication of new reactor components from the reclaimed metal. The processes required to permit hands-on recycling appear to be technically feasible, and demonstration experiments are recommended

[en] The alloy V-5Cr-5Ti (Teledyne Wah Chang heat 832394) was received in the form of a 6.35 mm plate and was rolled to 3.81 mm plate and 0.76 mm sheet. The 3.81 mm plate was used for Charpy impact specimens and the 0.76 mm sheet was used for tensile specimens and welding experiments. Since interstitial impurities are important strengthening and embrittling agents in refractory metals, all anneals had to be done in ultra-high vacuum furnaces

[en] The objective of this task is twofold: to provide an inventory of vanadium alloy sheet material for testing in other parts of the development program and to investigate the importance of process variables on the properties of the candidate vanadium alloys. This objective provides for the establishing of a materials processing flowstream that is capable of synthesizing vanadium base alloys and fabricating cast alloys to a final flat stock form. Initial efforts are focused on the V-Cr-Ti alloy system, with priority being given to the V-15Cr-5Ti alloy. Other alloys selected for development include V-10Cr-5Ti and V-10Cr-10Ti. 1 ref., 3 figs., 1 tab

[en] The experimental study of transport and equilibrium properties of oxygen in vanadium-based alloys was made by EMF measurements on solid electrolytic cells over the temperature range of 873 to 1423⁰K. The oxygen diffusion in vanadium was not significantly modified by small additions of Ti, Cr, Ni, Nb and Ta. The increase in the activation energy for oxygen diffusion in the V-based alloys containing Cr, Ni, Nb and Ta probably reflects the effect of these substitutional solutes on the activity coefficient of oxygen. The oxygen activity was increased by the addition of 1 at % of Cr, Ni and Nb, and decreased by the addition of Ti and Ta. However, the effects in the alloys containing Nb and Ta are very small

[en] Permeation and reemission of deuterium for the vanadium alloy, V-15Cr-5Ti, was investigated using 3 keV, D₃⁺ ion beams from a small accelerator. The experiments consisted of measurement of the deuterium reemission and permeation rates as a function of implantation fluence for 0.5 mm thick specimens heated to temperatures from 623 K to 823 K. Implantation-side surface characterization was made by simultaneous measurements of sputtered ions with a secondary ion mass spectrometer (SIMS). For the experimental conditions used, the steady-state deuterium permeation flux in V-15Cr-5Ti is approximately 18% of the implantation flux. This is approximately 1000 times that seen in the austenitic stainless steel, PCA, and 200 times that seen in the ferritic steel, HT-9, under comparable conditions. Measurement of deuterium diffusivity in V-15Cr-5Ti using permeation break-through times indicates that D = 1.4x10^-8 exp(-0.11 eV/kT)(m²/s), over the temperature range 723 K to 823 K. (orig.)

[en] Laser welding is potentially advantageous because of its flexibility and the reduced amount of material affected by the weld. Bead-on-plate and butt welds were previously performed to depths of about 4 mm with a 6-kW CO₂ laser on V-4%Cr-4%Ti and V-5%Cr-5%Ti alloys. These welds were made at a speed of 0.042 m/s using argon purging at a flow rate of 2.8 m³/s. The purge was distributed with a diffuser nozzle aimed just behind the laser beam during the welding operation. The fusion zones of welds made under these conditions consisted of very fine, needle-shaped grains and were also harder than the bulk metal (230-270 dph, compared to ∼180 dph for the bulk metal). A limited number of impact tests showed that the as-welded ductile-brittle transition temperatures (DBTT) was above room temperature, but heat treatment at 1000 degrees C for 1 h in vacuum reduced the DBTT to <-25 degrees C. Activities during this reporting period focused on improvements in the purging system and determination of the effect of welding speed on welds. A 2-kW continuous YAG laser at Lumonics Corp. in Livonia, MI, was used to make 34 test welds for this study

[en] The following topics are discussed in this section: (1) preparation of V metal, (2) purification, (3) alloy melting, (4) primary working, (5) secondary working, and (6) welding

[en] A joint experiment on the irradiation response of simple vanadium alloys has been initiated under the auspices of the DAFS and BES progams. Specimen fabrication is nearly complete and the alloys are expected to be irradiated in lithium in FFTF-MOTA Cycles 7 and 8

[en] The technique of determination of optimum conditions of rotary extrusion using simplex method of experiment planning is described. The use of the technique is discussed in reference to intermediate products of the BB-8 vanadium base alloy fabricated by pressing with further machining. It is shown that the smaller ball diameter is at great speed of axis displacement of the rolling head, the more optimum conditions of rotary extrusion are. The technique makes it possible to produce tube samples of the 130x1.5 and 100x1.5 mm diameter, with the +-0.2 mm diameter size accuracy, <= 10% wall thickness difference and high purity of inner and outer surface