D-T operation on TFTR

Abstract

Abstract The Tokamak Fusion Test Reactor (TFTR) has operated safely and routinely with tritium fuel since November 1993. Experiments conducted during this time have demonstrated improved plasma confinement properties, the first measurements of alpha heating and transport and the ICRF heating and current drive of D-T plasmas. Reactor level fusion power densities up to 2.8 MW m −3 have been attained as well as more than 10 MW of fusion power and 6.5 MJ of fusion energy per pulse. In support of these accomplishments, the TFTR equipment has met or exceeded the original design values. The toroidal magnetic field has been upgraded from 5.2 to 6.0 Tesla (on-axis), the neutral beams have injected up to 40 MW with a combination of deuterium and tritium fueling and the ICRF systems have been operated at various frequencies, from 30 to 64 MHz, to support an assortment of fast wave experiments. From November 1993 through July 1996, there have been 19 725 plasma shots. These include 841 deuterium-tritium pulses which have produced a total of 4.8 × 10 20 D-T neutrons and 1.4 GJ of fusion energy. More than 864 kCi (almost 90 g) of tritium have been processed through the TFTR facility while constrained to a site limit (‘in-process’) of 50 kCi. A low tritium inventory cryogenic distillation system has been recently installed and tested to provide on-site repurification of the plasma exhaust. Maintenance and repair activities have become routine in this facility. Hundreds of calibrations, repairs and installations requiring work on tritium contaminated and activated systems have been performed. Utilizing As Low As Reasonably Achievable (ALARA) principles, the radiation exposure to workers has been comparable to that experienced during the previous deuterium-only operating phase. The total annual site boundary dose, due to all pathways (prompt neutron radiation, activated air and controlled tritium release), has been less than 3 μSv, or 3% of the design limit of 100 μSv and 0.3% of the regulatory limit of 1 mSv.