Reactor Design
Fusion Torus
The Bulk of the reactor system is the Fusion Torus. This massive Tokamak style reactor is designed to be able to run for years without stopping, using incredibly durable materials, catonite lining to assist with power production, molten salts for cooling, and thick layers of self repairing materials inside of the reaction chamber itself.
The design itself is concerned with reliability, efficiency, and power output in that order, resulting in an incredibly heavy reactor design with poor acceleration characteristics but massive Delta V and energy output that can operate for the entire duration of a multi-year mission.
The reactor is also intended to be used as part of the engine system, super heating reaction mass for high efficiency propulsion, or diverting reactor plasma out of the reactor to increase thrust as the cost of energy output.
Fission Reactor
Intended to be used to start the Fusion Torus from a completely offline state, the fusion drive assembly also has three fission reactors designed to fully charge the Fusion Torus as part of the startup procedure.
RTG
Providing a small amount of power at all times, the drive systems' RTS use nuclear decay to reliably produce a small amount of power at all times. Even in the event of a catastrophic system failure, RTGs will provide power, allowing for the automated control systems of the drive to restart and carry out any needed operations.
Drive Bell
In line with the design philosophy of being able to run for years without maintenance, the drive system contains a drive bell that is large and heavy. It is designed to handle both the long term wear from the thermally heated reaction mass from the reactor as well as from chemical rocket fuels or reactor plasma itself.
Service and maintenance
Although the drive assembly is intended to be run without maintenance for years, in practicality maintenance is suggested to occur more often than every 10 years. Due to the mission profile of high risk, extreme distance missions, it is expected that the reactor will receive a full rebuild every time a long duration mission is completed or anytime the opportunity to do so presents itself.
Near term maintenance
Short of a full rebuild, there are additional steps that can be taken to ensure the longevity of the engine system.
Drive Bell Examination
Micrometeorites, dust, and even cosmic radiation can cause damage to the Drive Bell. The Bell itself is designed to be thick enough to survive such damage in the long term but the outer paneling should be regularly examined and replaced as needed.