A. Nagy, E. Amerescu, W. Blanchard, R. Camp, M. Casey, K. Chase, M. Cropper,
T. Czeizinger, M. DiMattia, C. Gentile, J. Gething, M. Gibson, J. Langford, J. Hosea,
D. Hyatt, M. Kalish, J. Kamperschroer, S. Langish, D. Miller, D. Mueller, G. Pearson,
S.Raftopoulos, R. Raucci, T. Stevenson, A. vonHalle, and J. Winston
Princeton Plasma Physics Laboratory
Princeton, NJ 08543
The Toroidal Fusion Test Reactor (TFTR) has injected greater than 800K Curies combined through the vacuum vessel and Neutral Beam (NB) tritium gas injectors. Out of this quantity approximately 50,000 Curies has entered the vacuum vessel. The TFTR has had two short term outages during DT operations plus the final shutdown after DT operations in which tritium held up in the vessel and NBs has been actively recovered with corresponding recovery values of: outage (No.1) 8600 Curies, (No. 2) 4600 Curies and the final shutdown approximately 3500 Curies. The methods for recovering this included vessel baking to 150oC during Deuterium Glow Discharge Cleaning (DGDC), Helium Oxygen GDC, Pulse Discharge Cleaning (PDC), and moist air purges. In addition, at room temperature (22oC), purges were performed using nitrogen, dry air, deuterium soak at low pressures, and moist air. The processes showing the best recovery efficiency were the GDC, HeO GDC, and moist air purges at room and elevated temperatures.
The tritium entering the vessel at high energy through the NB 's is buried in the carbon composite tiles and has a longer time constant for removal than the vessel injected tritium. Data shows that the bulk of surface tritium is removed in the presence of oxygen in the form of water vapor and removal is accelerated at elevated temperatures. The active tritium removal processes are followed by continuous outgassing at low levels.
The TFTR tritium removal processes and their corresponding removal rates and quantities are compared and discussed.
*Work supported by U.S. DOE Contract No. DE-AC02-76-CHO3073.