Health physics and radioactive waste considerations for the TFTR

摘要

The Tokamak Fusion Test Reactor (TFTR) began high power fusion operations, with tritium, in November of 1993. These operations utilize a 50/50 mixture of deuterium and tritium which yields 14 MeV neutrons at a magnitude of 2.0E+18 per 3 second pulse. These high energy neutrons interact with the vacuum vessel, neutral beams, confinement coils and other structural and peripheral materials resulting in fusion activation products. These operations also consist of the delivery, storage, injection and subsequent processing of tritium gas in support of the D-T fusion program. These systems have manipulated and processed 208 PBq of tritium throughout the past year. The operational health physics program involves maintenance on activated materials and tritium contaminated systems. Survey data and findings are collected on routine and special maintenance situations ranging from work on small volume piping to large volume neutral beam systems. The results of radiological measurements are described in relation to the differentiation of elemental tritium to tritium oxide in worker's breathing zones and the associated general work area. The contamination levels, airborne radioactivity, and oil concentrations are also compared. Measurements for gamma radiation are performed to determine personnel access requirements and for comparison to activation and decay models as a planning tools. TFTR presents many unusual challenges with regard to dismantling, packaging and disposal of its components and ancillary systems. A functional time phased radioactive waste generation schedule was developed to enhance project planning. This project will be the first demonstration of the decommissioning of a tritium fuelled fusion test reactor.