Abstract
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 balanceofplantmodelling 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 doserate calculation with the Serpent code,which is available for a further coupling to thermohydraulics.
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 balanceofplantmodelling 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 doserate calculation with the Serpent code,which is available for a further coupling to thermohydraulics.
Original language  English 

Qualification  Doctor Degree 
Awarding Institution 

Supervisors/Advisors 

Award date  19 Jun 2018 
Publisher  
Print ISBNs  9789526080468, 9789513886516 
Electronic ISBNs  9789526080475, 9789513886509 
Publication status  Published  2018 
MoE publication type  G5 Doctoral dissertation (article) 
Keywords
 plasma physics
 magnetic confinement
 scenario modelling
 fusion neutrons
 synthetic diagnostics
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Siren, P. (2018). Modelling of JET and ITER reactor relevant plasma neutron source for neutronics calculation chain: Dissertation. VTT Technical Research Centre of Finland. https://www.vtt.fi/inf/pdf/science/2018/S180.pdf