(FT/P2-13) Assessment of Radiation Streaming Effect upon Radiation Loads to Inboard TF-coil of DEMO Utilizing HCLL Blanket

J.D. Jordanova1), U. Fischer2), P. Pereslavtsev2)
1) Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria
2) Forschungszentrum Karlsruhe, Postfach 3640, 76021 Karlsruhe, Germany

Abstract.  Neutron and photon calculations have been performed to assess the effect of radiation streaming through the gaps between blanket modules upon the radiation loads to the super-conducting TF-coil at the inboard side. These include the fast neutron fluence to the superconductor, the peak nuclear heating in the winding pack, the radiation damage to the copper stabilizer and the radiation dose absorbed by the Epoxy resin insulator. Three-dimensional Monte Carlo radiation transport code MCNP4C and a suitable 20 deg.-sector model of DEMO reactor, developed by FZK, have been employed in the analysis. The model is based on PPCS AB concept employing HCLL blanket. A 4000 MW fusion power and 40 fpy of plan operation have been assumed. The poloidal profiles of radiation loads in respect to the torus mid-plane have been investigated in several variants of the gap widths and compositions of additional shield plugging the gaps. It was found that the design limit of all the responses considered could only be met if the toroidal and poloidal gaps are plugged by LTS material, the later being made of borated steel, WC and water coolant.

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