COSTING THE PCAST MACHINE

In September, 1995, the Office of Fusion Energy commissioned a three m onth study to assess the recommendations made by President's Commissio n on the Advancement of Science and Technology (PCAST) for a reduced s cope of the International Thermonuclear Experimental Reactor (ITER) mi ssion. The PCAST suggested that a device, operating with a moderate pu lse length and corresponding reduced mission for ignition and burn con trol, could be built at a significantly lower cost than the present IT ER design. If such a machine were technically feasible and less expens ive than ITER, PCAST reasoned that the U.S. could participate as a ful l partner in an international collaboration to build such a device. Th e study's charter was to develop a design to meet the reduced mission and to compare its cost with ITER using ''ITER Physics.'' In addition, the study explored the cost and performance sensitivity to variations in design approach and physics performance. Finally, to better unders tand the cost of such a project in U.S. terms, the design example was also estimated in a U.S. Total Project Cost format. This paper details the cost estimate approach in arriving at the cost of the PCAST machi ne. Since the project schedule or funding profile are yet to be establ ished, the cost comparisons based on percentage basis to ITER were mor e appropriate than absolute dollar comparisons. In addition, the costs of this device were also compared to the Burning Plasma Experiment(BP X) - a short pulse ignition device designed in the early 1990's, and t he Tokamak Physics Experiment (TPX) a long pulse, advanced tokamak can celed recently by the Department of Energy (DOE) due to Congressional budget constraints. Comparisons were limited to construction costs sin ce agreements between potential international partners on the PCAST ma chine could significantly impact the treatment of engineering/physics, R&D, and other costs such as construction management, engineering sup port during construction, and commissioning costs. The construction co sts of the PCAST device were estimated to be approximately $2,600M. Th is is approximately 45% of the ITER construction costs, approximately 330% of the BPX estimate, and approximately 685% of the TPX estimate. Due to budget and time constraints, cost scaling was used versus perfo rming a ''bottoms up'' estimate. This approach involves considerable u ncertainty. Additionally, there was also a range of costs associated w ith future design development. Both considerations were clearly a fact or in the PCAST machine where there was relatively little time for det ailed evaluation, design development, or optimization. Given these unc ertainties, we believe it is most appropriate to describe the construc tion estimate for the PCAST machine as approximately 50% of the cost o f ITER, with a range of 40% to 60%. Using the U.S. Total Project Cost methodology, the total cost of the PCAST machine was estimated to be a pproximately $5.8 billion in FY-95 dollars, including contingency allo wances.