(FT/P2-10) Neutronics R&D Efforts in Support of the European Breeder Blanket Development Programme

U. Fischer1), P. Batistoni2), A. Klix1), I. Kodeli3), R.L. Perel4)
1) Forschungszentrum Karlsruhe, Institut fuer Reaktorsicherheit, Karlsruhe, Germany
2) Associazione ENEA-Euratom, ENEA Fusion Division, Via E. Fermi 27, I-00044 Frascati, Italy
3) IAEA representative at OECD/NEA Data Bank, 92130 Issy-les-Moulinaux, France
4) Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel

Abstract.  The EU fusion technology programme considers two blanket development lines, the Helium-Cooled Pebble Bed (HCPB) blanket with Lithium ceramics pebbles as breeder material and beryllium pebbles as neutron multiplier, and the Helium-Cooled Lithium-Lead (HCLL) blanket with the Pb-Li eutectic alloy acting both as breeder and neutron multiplier. The long-term strategy aims at providing validated engineering designs of breeder blankets for a fusion power demonstration reactor (DEMO). As an important intermediate step, the breeder blankets need to be tested in a real fusion environment as provided by ITER. HCPB and HCLL Test Blanket Modules (TBM) have been accordingly designed for tests in dedicated ITER blanket ports. The nuclear design and performance of the breeder blanket modules rely on the results provided by neutronics design calculations. Validated computational tools and qualified nuclear data are required for high prediction accuracies including reliable uncertainty assessments. Complementary to the application of established standard tools and data for design analysis, a dedicated neutronics R&D effort is therefore conducted in the EU. This includes the development of dedicated computational tools, the generation of high quality nuclear data and their validation through integral experiments. The recent neutronic design efforts have been devoted to the European DEMO reactor study comprising (i) Monte Carlo based pre-analysis for the dimensioning of the shielding system, (ii) the generation of a generic CAD based Monte Carlo geometry model, and (iii) performance analysis for HCLL and HCPB based DEMO variants. The recent focus of the validation effort is on neutronics TBM mock-up experiments. The first experiment of this kind was performed on a TBM mock-up of the HCPB breeder blanket. The follow-up experiment on a neutronics HCLL TBM mock-up is currently under preparation. Computational pre-analysis were performed to optimise the design of the mock-up configuration and provide first uncertainty assessments. The MCSEN code has been extended to enable, in an efficient way, the calculation of sensitivities by the track length estimator approach. A first successful test application to a complex tokamak configuration was recently performed for the HCPB TBM in ITER.

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