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TFTR has begun its campaign to study deuterium-tritium fusion under reactor-like conditions. Variable amounts of deuterium and tritium neutral beam power have been used to maximize fusion power, study alpha heating, investigate alpha particle confinement, and search for alpha driven plasma instabilities. Additional areas of study include energy and particle transport and confinement, ICRF heating schemes for DT plasmas, tritium retention, and fusion in high βp plasmas. The majority of this work is done in the TFTR supershot confinement regime. To obtain supershots, extensive limiter conditioning using helium fueled ohmic discharges and lithium pellet injection into ohmic and neutral beam heated plasmas is performed, resulting in a low recycling limiter. The relationship between recycling and core plasma confinement has been studied by using helium, deuterium and high-Z gas puffs to simulate high recycling limiter conditions. These studies show that confinement in TFTR supershots is very sensitive to the influx of neutral particles at the plasma edge.

Two plateaux are observed in the desorption isotherm for palladium hydride: a lower plateau pressure for a hydrogen/metal atom ratio (H/M) less than about 0.3 and a slightly higher plateau pressure for H/M greater than about 0.3. This higher pressure corresponds to the reported pressure for palladium hydride. These observations were made for a large surface area palladium powder exposed to both protium and tritium. Helium buildup from tritium decay decreases the lower plateau pressure but does not affect the observations for H/M greater than about 0.3. A multiple-energy hydrogen site occupancy model is proposed to explain qualitatively both the dual plateau and the helium effect in palladium hydride.

Helium from tritium decay causes the desorption isotherm plateau pressure for LaNi4.25Al0.75 tritide to be lowered. From the shape of the 3He altered isotherm, it appears that the material becomes disordered and possibly disproportioned. The microstructure of the parent LaNi4.25Al0.75 tritide material is believed to influence the behavior of 3He from tritium decay.

Helium dynamics in La-Ni-Al tritides have been observed by measuring the plateau pressure decrease for the pressure of tritium in equilibrium with the solid as a function of helium composition. Calculations suggest that a crystal lattice volume expansion, caused by helium, stabilizes the tritide. Temperature cycling the helium-altered, tritium-saturated intermetallic partially restores the plateau pressure. These data are discussed in the context of immobile helium which can gain mobility as the tritide ages.