Vacuum and wall problems in precursor reactor tokamaks

The Princeton Large Torus (PLT) will be completed in 1975 and two other CTR oriented toroidal plasma devices, the Poloidal Divertor Experiment (PDX) and the Tokamak Fusion Test Reactor (TFTR). are planned to be completed in 1977 and 1981. The vacuum systems of these machines must satisfy stringent requirements because of unusual operating conditions, such as, magnetic field induced strains and eddy currents, energetic particle and photon bombardment, large transient gas loads, and the use of 100 Curie quantities of tritium. In addition, novel vacuum wall surfaces and fast moving mechanical or magnetic plasma limiters will be required to minimize the influx of impurities during discharges. (auth