Q-DEMO

Q-DEMO is the name of QST’s ITER-sized fusion demonstration-reactor concept. QST is the research organization; Q-DEMO is the proposed reactor program. The concept combines work from Japan’s earlier JA DEMO studies with ITER engineering experience, seeking a shorter route to a meaningful electricity-generation demonstration in the 2030s. Publication of a conceptual design establishes a defined development proposal, not a completed or operating plant. QST: Q-DEMO conceptual design announcement

The published design summary sets out three stages. The first targets short-pulse electricity generation around net-electric breakeven. The second adds a breeding blanket and longer pulses, at least 30 minutes, to combine electricity and fuel-breeding demonstrations. A later stage targets steady-state operation with roughly 100 MW of net electricity. These are prospective design objectives; the 2030s ambition must not be read as a guarantee that all three stages will be completed within that decade. QST: Q-DEMO conceptual design summary

The approach aims to reuse manufacturing experience from ITER and integration knowledge from JT-60SA while developing the systems needed for a power-producing reactor. QST identifies research infrastructure at Naka and Rokkasho as part of that effort. A design team’s location is not sufficient evidence of a final reactor construction site. When comparing Q-DEMO with other programs, distinguish fusion power, generator output and net electricity after the plant’s own consumption. Those measures describe different boundaries of the system. QST: Q-DEMO conceptual design announcement

A future D–T reactor must recover energy carried by fusion neutrons as heat and transfer it through cooling and heat-exchange systems to generating equipment. Its blanket also has to produce tritium. Extracting, purifying, circulating and reinjecting fuel must work alongside heat recovery; plasma confinement alone does not establish a functioning power plant. Fusion reaction basics Blanket and fuel research

Gross electrical output is the generator’s production. Net electricity is what remains after the plant’s own heating, cooling, vacuum and auxiliary consumption. A demonstration around net-electric breakeven is therefore different from supplying a substantial electricity surplus. Plasma gain Q compares fusion power with external power delivered to heat the plasma; it is not a whole-plant electrical-efficiency figure. These boundaries are essential when comparing Q-DEMO with other designs. ITER explanation of plasma gain

Q-DEMO is a separate reactor concept, not a proposal to convert ITER itself into a power station. Using established designs can narrow engineering gaps, but changed operating conditions still require qualification. Material integrity, heat loads, fuel balances, remote maintenance and manufacturability remain important tests of the concept. Design-team activity at Rokkasho must also be distinguished from a confirmed construction site. Q-DEMO design summary