Stafford Fusion Lab 
Researching the future 


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The Snowdon Tokamak


Based in Stafford, the county town of Staffordshire in the centre of England, Stafford Fusion Lab is currently working on the construction of a small experimental deuterium-deuterium nuclear fusion reactor (The Snowdon Tokamak). It is planned for first plasma to be achieved by February 2028.

Tokamak Design

Major radius (Ro) = 0.165m
Minor radius (a) = 0.13m
Aspect ratio (Ro/a) = 1.269
Maximum Elongation (b/a) = 2.88

The tokamak is intended to be used for research into the startup conditions in tokamaks. Because it is designed to run for 3mS super conductors will not be required as even for the thin copper inner legs of the TF coil the heating is expected to be only 3 degrees Celcius per 3 millisecond cycle of operation.


The provisional design of the main vacuum chamber is shown below:



The vacuum chamber will be entirely surrounded by six inches of lead (Pourshahab et al. 2023). The top and bottom layers will be attached to the vacuum chamber and the two curved sections, which will overlap and entirely surround the sides of vacuum chamber, will be attached to moveable frames and will be pinned in place. This will allow easy removal for accessing the vacuum chamber and diagnostic equipment.


The vacuum connectors below will be used for connecting the vacuum pump (KF63 half nipple on the left), the deuterium supply (kf25 half nipple in the middle) and the kf16 half nipples will be used for the limiter supports and the diagnostic equipment (right.)



Both the vacuum chamber and the adjustable limiters will be lined with the graphite sheets (Asif et al. 2005) below:



The limiters will be made up of two circular loops of stainless steel with plasma facing graphite linings, each supported on three stainless steel rods that will be height adjustable through vacuum seals mounted on KF16 vacuum ports using the vacuum seals below:



The vacuum chamber will also have two 150mm viewports that will be made up of the parts shown below (at least 4 clamps per viewport will also be required):



All the tokamak coils (with the exception of three quarters of the TF windings) will be made up of either 5mm or 6mm diameter enamel copper wire rated at 5kV (part numbers TX5000D-D355 and TX6000D-D355 from the Scientific Wire Company). The wire to be used is shown below



Some aspects of the design of this tokamak are based upon the Medusa Tokamak (Garstka, 1997)

References

Asif, M. et al (2005). Plasma density behavior with new graphite limiters in the Hefei Tokamak-7. Physics of Plasmas, Phys. Plasmas 12, 082502 (2005). https://doi.org/10.1063/1.1995627
Garstka, G (1997). Startup and Stability of a small Spherical Tokamak. Dissertation University of Wisconsin-Madison. UMI Number 9803422.
Pourshahab, B., Rasouli, C., & Iraji, D. (2023). Dose mapping of hard X-ray radiation due to runaway electrons in Alvand tokamak using combination of high-dose and low-dose level dosimeters. Fusion Engineering and Design, 197, 114065. https://doi.org/10.1016/j.fusengdes.2023.114065

Any enquiries should be directed to: admin @ staffordfusionlab.co.uk