OVERVIEW OF THE ARIES-RS REVERSED-SHEAR TOKAMAK POWER-PLANT STUDY

The ARIES-RS tokamak is a conceptual, D-T-burning 1000 MWe power plant . As with earlier ARIES design studies, the final design of ARIES-RS w as obtained in a self-consistent manner using the best available physi cs and engineering models. Detailed analyses of individual systems tog ether with system interfaces and interactions were incorporated into t he ARIES systems code in order to assure self-consistency and to optim ize towards the lowest cost system. The ARIES-RS design operates with a reversed-shear plasma and employs a moderate aspect ratio (A = 4.0). The plasma current is relatively low (I-p = 11.32 MA) and bootstrap c urrent fraction is high (f(BC) = 0.88). Consequently, the auxiliary po wer required for RF current drive is relatively low(similar to 80 MW). At the same time, the average toroidal beta is high (beta = 5%), prov iding power densities near practical engineering limits (the peak neut ron wall loading is 5.7 MW m(-2)). The toroidal-field (TF) coil system is designed with relatively 'conventional' materials (Nb3Sn and NbTi conductor with 316SS structures), and is operated at a design limit of similar to 16 T at the coil in order to optimize the design point. Th e ARIES-RS design uses a self-cooled lithium blanket with vanadium all oy as the structural material. The V-alloy has low activation, low aft erheat, high temperature capability and can handle high heat flux. A s elf-cooled liquid lithium blanket is simple, and with the development of an insulating coating, has low operating pressure. Also, this blank et gives excellent neutronics performance. Detailed analysis has been performed to minimize the cost and maximize the performance of the bla nket and shield. One of the distinctive features of this design is the integration of the first wall, blanket, parts of the shield, divertor and stability shells into an integral unit within each sector, The ma intenance scheme consists of horizontal removal of entire sectors. Pri or to the initiation of the ARIES-RS study, a set of top-level require ments and goals for fusion demonstration and commercial power plants w as evolved in collaboration with representatives from US electric util ities and from industry. The degree to which ARIES-RS reached these re quirements and goals and the necessary trade-offs are described and th e high-leverage areas and key R&D items are presented. (C) 1997 Elsevi er Science S.A.