[cromwellian]

In ARC the containment is not under vacuum, the reactor chamber is surrounded by molten salt of fluoride and lithium, and so the neutrons produced travel into molten salt where they collide and produce tritium.

It would help to actually watch the presentations. They’ve solved a lot engineering problems from Routine maintenance to blanket Renewal.

[Retric]

ARC reactors due use high temperature plasma in a near vacuum. “The confinement time for a particle in plasma varies with the square of the linear size, and power density varies with the fourth power of the magnetic field,[2] so doubling the magnetic field offers the performance of a machine 4 times larger.”

https://en.wikipedia.org/wiki/ARC_fusion_reactor