COOLING SYSTEM-DESIGN OPTIONS FOR A FUSION-REACTOR

The objective of a fusion power reactor is to produce electricity safe ly and reliably. Accordingly, the design, objective of the heat transp ort system is to optimize power production, safety, and reliability. S uch an optimization process, however, is constrained by many factors, including, among others: public safety, worker safety, steam cycle eff iciency, reliability, and cost. As these factors impose conflicting re quirements, there is a need to find an optimum design solution, i.e., one that satisfies all requirements, but not necessarily each requirem ent optimally. The SEAFP(5) reactor study developed helium-cooled and water-cooled models for assessment purposes. Among other things, the c urrent study demonstrates that neither model offers an optimum solutio n. Helium cooling offers a high steam cycle efficiency but poor reliab ility for the cooling of high heat flux components (divertor and first wall). Alternatively, water cooling offers a low steam cycle efficien cy, but reasonable reliability for the cooling of such components. It is concluded that an optimum solution includes helium cooling of low h eat flux components and water cooling of high heat flux components. Re lative to the SEAFP helium model, this hybrid system enhances safety a nd reliability, while retaining the high steam cycle efficiency of tha t model.