System Code Analysis of HELIAS-Type Fusion Reactor and Economic Comparison With Tokamaks

Abstract

Systems codes are commonly employed for the analysis and conceptual design of fusion reactors. For the helicalaxis advanced stellarator (HELIAS) line a new set of systems code models have been developed to account for the stellaratorspecific 3D aspects. The models have recently been implemented in the systems code PROCESS and verified with respect to different test cases. After having established confidence in the stellarator models, systems studies were carried out for the 5-field period HELIAS case to define the accessible reactor design window. In the multidimensional physics and engineering parameter space sensitivity studies are carried out for the reactor regime to ascertain tradeoffs between different parameters and costs. Exemplary design points are analysed in more detail using the plasma operation contour approach which, for example, can be used to determine the optimum start-up path to ignition. Finally, with a common set of non-device-specific models, the PROCESS framework allows a direct comparison of tokamaks and stellarators. Although the 5-period HELIAS is a larger machine in terms of major radius, the required mass for both concepts is comparable leading to similar construction costs.

First considerations on the Balance of Plant for a HELIAS fusion power plant

“…The current HELIAS concept is a large aspect ratio stellarator consisting of five identical field periods [5,10,11]. From a design point of view, it is thus meaningful that the BB heat transfer system follows this symmetry.…”

“…Considering these achievements, in this work we present a first conceptual design for the Balance of Plant of a helical-axis advanced stellarator (HELIAS) type fusion power plant [4,5].…”

Initial Exploration of High-Field Pulsed Stellarator Approach to Ignition Experiments

“…Calculations by complex systems codes [25] have not been carried out yet, and will be the subject of future work. However, the rough estimates presented may be sufficient for this initial stage of development.…”

“…Optimization of stellarator magnetic configurations continues worldwide [25,[96][97][98] and new stellarator concepts continue to emerge [96,99]. Hence, future versions of i-ASTER might have larger A, which usually gives higher beta limit b lim (''Assumptions and Governing Equations: Ignition Condition'' section, [30]), or higher number of field periods.…”

“…Only an initial estimate of possible operating points is sought here. Detailed plasma calculations using advanced codes [24,25] are left for future work, as the design advances.…”