Structural Assessments of the K-DEMO Blanket Modules

Authors: P. Titus, T. Brown, H. Zhang, A. Brooks, G. Neilson

Abstract: The Korean fusion demonstration reactor (K-DEMO) is in the early stages of conceptual design. Ceramic breeder blanket modules are being investigated. These have had extensive nuclear and thermal evaluations. Structural assessments are in process. This paper presents stress analyses performed at PPPL in support of the blanket design. Disruption loading, including the effects of ferromagnetic structural materials is evaluated. An approximate, but representative model of the blanket is used to evaluate a full set of normal thermal , pressure, and static magnetic loads. Disruption and faulted pressure loads are assessed as well. In one structural concept being considered for K-DEMO a semi-permanent shield is employed that also serves as support for the blanket modules. Inner and outer support shells are planned. The inboard blanket support structure and the outboard blanket structure are toroidally electrically continuous and are structurally connected. The inboard modules are keyed into the toroidally continuous support structure which reacts disruption loads from the blankets and from its own internal eddy currents and static magnetic loads. The support shells serve as nuclear and electromagnetic shields for the vessel. This arrangement is a part of a vertical maintenance concept, that removes the inboard blanket module components with a radial and vertical traverse and leaves much of the massive shielding and support structure in place. Normal and disruption blanket loads need to be quantified to show that these loads can be carried by the proposed structure, and to qualify the internals of the blanket modules. . The K-DEMO disruption analysis employs a simple modeling of the plasma by adjusting current densities in regions of the cross section defined for the plasma. Static magnetic loads for both normal operation and disruption have been added by an approximate method developed using a representative blanket and an ITER disruption simulation. Thermal loads are added based on surface and volumetric heating from NFRI.

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