r0005">We incorporated the Life Cycle Analysis (LCA) of tokamak type DEMO reactor and following commercial reactors as an extension of a system code.

r0010">We calculated COub>2ub> emissions from reactor construction, operation and decommissioning that is considered as a major environmental cost.

r0015">We found that the objective of conceptual design of the tokamak fusion power reactor is moved by changing evaluation index.

r0020">The tokamak fusion reactor can reduce COub>2ub> emissions in the life cycle effectively by reduction of the amount involved in the replacement of internal components.

r0025">The tokamak fusion reactor achieves under 0.174$/kWh electricity cost, the tokamak fusion reactor is contestable with 1500 degrees-class LNG-fired combined cycle power plant.