A staged approach to Indian DEMO

Abstract

We present a revised strategy for Indian DEMO in the context of new technologies and concepts in fusion research. The central idea behind the new strategy is that the power plant is a reactor-park consisting of multiple, preferably compact, reactors with moderate fusion power ($\sim$ 1000 MW) with 35~\% to 50 \% availability for each. The DEMO is a single net electricity producing unit that becomes the basis for replication into multiple units on a commercial scale. One of the key enablers for the revised strategy is the emergence of high-temperature superconductors for high field magnets. For a steady-state burn we show that there exists an optimum regime
of plasma β and confinement where the fusion gain is maximum. Thus, we adopt a strategy with moderate confinement regimes and plasma $\beta$. This makes current drive a necessity for the reactors. Based on these considerations a four-stage approach to DEMO is proposed. It is argued that an electricity producing pilot plant with fusion power of 200 MW - 300 MW is needed before the DEMO to establish the power performance, tritium breeding and its re-use over sufficiently long pulses. An integrated test facility must precede the pilot to test and qualify the technologies for the pilot stage. The revised approach takes into account realistic assumptions on power balance, current drive efficiency and magnet lifetime-dose; factors that pose constraints in identifying potential reactor configurations. Parameter choices for possible options for the integrated test facility (Fusion Engineering Science and Test - FEST), pilot plant and DEMO are presented that can be used to initiate conceptual designs and directed R\&D.