b'26 Partner News Summer 2021EnterpriseTokamak EnergyDelivering a 250kA pulse with Toroidal field power supply on ST40At Tokamak Energy our mission is to changerequired to force together chargedUltracapacitors are capable of storing the way the world generates power deuterium and tritium particles thatand discharging energy very quickly and forever. We are developing a scalablenaturally repel each other and get themeffectively. In order to deliver the pulse fusion solution that will give the world anclose enough together to fuse. requirements, S40 power supply requires attractive new base-load power sourcea large internal stored energy. Each that is plentiful, safe, cost effective, secureST40 requires several power supplies tocapacitor module is rated at 48 volts @ and clean. Our target is to demonstrate theprovide sufficient internal stored energy for165F. feasibility of fusion as an energy source bya two second pulse every 15 minutes during 2030. operational periods. The TF (Toroidal Field)It is convenient to model them as a power supplies is key to achieve this andseries RC circuit. For this we will consider To achieve this objective, we are workingable to deliver a flat top current of 250kA. E=1/2CV Where E=Energy stored in stages, ensuring our technology isC=Capacitance in farads and V=Charge robust and meets clearly defined targetsAll power supplies are required to delivervoltage. It is also required to know the and criteria. This enables us to developenergy from a stored energy source duecircuit resistance as this is one of the our tokamaks faster and helps us remainto the nature of the Spherical Tokamaklimiting factors for the peak pulse current. on track to meet our ultimate target. Ouroperations in short duration.The power supply has 108 parallel circuits compact spherical tokamak, called the ST40,(shown right as a single circuit) which in is the latest development in our excitingBecause the short two second pulsetotal has a stored energy E=144MJ. Each mission to achieve commercial fusion power. length, Ultra capacitors were chosen ascircuit requires an IGBT (Insulated-Gate the preferred technology in most systemsBipolar Transistor) switch to manage the Our next milestone on for ST40 is to achievebecause of their ability to use series andpeak current in each limb of 2.3kAmps to 100m degrees. This is the temperatureparallel connections. gain the full duty output of 250kA.'