VALIDATION OF SERPENT FOR FUSION NEUTRONICS ANALYSIS AT JET

¹ Reactor Physics Department, Jožef Stefan Institute Jamova cesta 39, 1000 Ljubljana, Slovenia
² University of Ljubljana, Faculty of Mathematics and Physics Jamova cesta 19, 1000 Ljubljana, Slovenia
³ Fusion Technical Unit Via E. Fermi 45, I-00044 Frascati, Italy
⁴ CCFE, Culham Science Center Abingdon, OX14 3DB, UK
⁵ VR, Department of Physics and Astronomy, Uppsala University Box 516, SE-75120 Uppsala, Sweden
⁶ See the author list of E. Joffrin et al. accepted for publication in Nuclear Fusion Special issue 2019 https://doi.org/10.1088/1741-4326/ab2276

andrej.zohar@ijs.si
ziga.stancar@ijs.si
paola.batistoni@enea.it
sean.conroy@physics.uu.se
luka.snoj@ijs.si
igor.lengar@ijs.si

Published online: 22 February 2021

Abstract

Fusion neutronics analysis before and after experiments at JET is traditionally performed using Monte Carlo particle transport code Monte Carlo N-Particle. For redundancy and diversity reasons there is a need of an additional Monte Carlo code, such as Serpent 2, capable of fusion neutronics analysis. In order to validate the Serpent code for fusion applications a detailed model of JET was used. Neutron fluxes and reaction rates were calculated and compared for positions outside the tokamak vacuum vessel, in the vacuum vessel above the plasma and next to a limiter inside the vacuum vessel. For all detector positions with DD and DT neutron sources the difference between neutron fluxes calculated with both Monte Carlo codes were within 2σ statistical uncertainty and for most positions (more than 90 % of all studied positions) even within 1σ uncertainty. Fusion neutronics analysis in the JET tokamak with Serpent took on average 10 % longer but this can be improved by changing the threshold value for determination of the transport method used. With the work presented in this paper the Serpent Monte Carlo code was validated to be a viable alternative to MCNP for fusion neutronics analysis for the JET tokamak.