From the 2008 overview of Fusion research by R. Stambaugh of General Atomics:
The Fusion Development Facility Mission (FDF): Develop Fusion’s Energy Applications but the Fusion Development Facility could also be the basis for a steady state neutron source for transmuting nuclear waste from nuclear fission reactors
• Develop the technology to make
• By using conservative Advanced Tokamak physics to run steady-state and produce 100-250 MW fusion power
– Modest energy gain (Q<5)
– Continuous operation for 30% of a year in 2 weeks periods
– Test materials with high neutron fluence (3-8 MW-yr/m2)
– Further develop all elements of Advanced Tokamak physics, qualifying them for an advanced performance DEMO
The current largest tokomaks (DIII-D (general atomics), Japan's JT-60 and the EU JET) have had about 30 seconds of sustained operation. Upgrades or better versions like the FDF are needed to achieve sustained operations necessary for commercial transmutation.
The first main blanket fusion system could be sufficient for a 100MW, 30-50% available fusion neutron source. The second main blanket seems definitely seems good enough for transmutation purposes. So 8-13 years to get a fusion transmutation system seems possible. The new Super X divertor success in negating the need for better containment walls could accelerate the schedule.
Capabilities of current and planned fusion reactors.
Fusion systems for Transmutation Need What Capabilities