Modelling of JET and ITER reactor relevant plasma neutron source for neutronics calculation chain: Dissertation

Paula Siren

    Research output: ThesisDissertationCollection of Articles


    It is essential for the research of reactor relevant plasmas to understand how heat transfer isaffected by the properties of and phenomena in the plasma fuel. The major part of heat istransferred out via energetic neutrons. The neutrons must be taken into account as a heat sourceas well as from the perspective of material activation and induced reactions. In simulations thecalculation chain from the reactants to products, heat transfer and material effects requires thecoupling methods in plasma physics, reactor analysis and thermohydraulics calculation.
    This thesis focuses on reactor relevant plasmas. The first part discusses plasma operationalscenarios concentrating especially on advanced tokamak scenarios. The time evolution of the safetyfactor q is strongly connected to total plasma current and confinement, so the data analysis basedon the identity plasma experiments is extended with predictive current diffusion simulations. Asensitivity test with respect to typical plasma parameters carried out for time evolution of q andinternally generated bootstrap current density.
    The second and third parts consider fusion products and their characterisation. The simulationtool AFSI fusion source integrator is presented and validated using JET tokamak data. Theproduction rate and neutron spectrum is calculated in a geometry which correspond to realdiagnostics based on the experimental data. Additionally, the results have been comparedqualitatively to the experimental measurements when with good agreement between calculatedand measured values.
    In the fourth part, the calculation chain from the modelling of plasma fuel to the balance-ofplantmodelling is described with the focus on the coupling of plasma physics and neutronics. Asa demonstration case, the predictions ITER plasma data and a CAD model have been used. AFSIhas been coupled to the ASCOT particle following code, which defines the distribution and energyof the reactants. A neutron source was provided for a dose-rate calculation with the Serpent code,which is available for a further coupling to thermohydraulics.
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Aalto University
    • Tuomisto, Filip, Supervisor, External person
    Award date19 Jun 2018
    Print ISBNs978-952-60-8046-8, 978-951-38-8651-6
    Electronic ISBNs978-952-60-8047-5, 978-951-38-8650-9
    Publication statusPublished - 2018
    MoE publication typeG5 Doctoral dissertation (article)


    • plasma physics
    • magnetic confinement
    • scenario modelling
    • fusion neutrons
    • synthetic diagnostics


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