Figure A.2. Energy flow in a conceptual inertial fusion energy plant. Note QE = 1/f.
Energy gain does not, of course, guarantee commercial viability. Key challenges remain even after high gain is achieved. These will be discussed in detail in the final report, but they include:
• Low-cost targets. For example, a target producing a fusion energy, ED, of 200MJ could make net electricity, Egrid ~ 80MJ ~ 22kWh, or about $1 worth of electricity at current prices. The target cost should be some small fraction of this.
• Repetitive ignition of targets. To produce a gigawatt of electrical power, targets with ED = 200MJ must be ignited roughly 12 times a second.
• Reliable target chamber and blanket to extract power and breed tritium, a challenge shared with magnetic fusion.