By combining arc casting and electron beam melting, spectroscopically pure tantalum and alloys were produced, suitable for containment of molten Pu-Fe alloys. The 0.1% W alloy was used for the first LAMPRE loading. The effects of a large number of additives on the corrosion resistance of tantalum were tested. Additions of up to 10% tungsten gave increasing endurance. Specimens of tantalum irradiated with neutrons to give 3% conversion to tungsten were still satisfactory in mechanical properties for reactor use. Either tungsten addition or traces of yttrium raise the one-hour recrystallization temperature of tantalum by 400°C. Effects of internal strain, critical strain, and precipitation hardening in tantalum alloys were studied. High-temperature annealed tantalum had superior corrosion resistance to the fuel, while impact extruded and ironed material was better than deep-drawn metal. Mechanical tests on tantalum with added interstitial elements showed that their presence to the extent expected in LAMPRE would be unlikely to weaken the tantalum. While small amounts of hydrogen, nitrogen, and carbon in the tantalum had no effect on corrosion, oxygen was found to promote plutonium attack on the metal.