Neutron streaming studies along JET shielding penetrations

Abstract

Abstract.Neutronic benchmark experiments are carried out at JET aiming to assess the neutronic codes and data used in ITER analysis. Among other activities, experiments are performed in order to validate neutron streaming simulations along long penetrations in the JET shielding configuration. In this work, neutron streaming calculations along the JET personnel entrance maze are presented. Simulations were performed using the MCNP code for Deuterium-Deuterium and DeuteriumTritium plasma sources. The results of the simulations were compared against experimental data obtained using thermoluminescence detectors and activation foils.

14 MeV neutron streaming calculations for JET-like maze entrance using TRIPOLI-4 Monte Carlo code

“…Using two-step simulation approach, two different calculation ways were performed to decrease the variances of calculated neutron fluence and ambient dose equivalent. Both the MC-MC approach using a midway surface source [3] and the Deterministic-MC one [1] using deterministic generated weight windows produced overestimated results (C/E >> 1) in JET maze entrance zone.…”

“…The JET torus hall and its south-west (SW) maze entrance configuration were reported in previous publications for the 2013-2014 JET campaigns [1][2][3]. Figure 1 shows the JET torus hall and the previous TLDs measurement locations for SW maze (A1-A7, and B8).…”

“…The SW maze configuration provides four rightangle turns. The total length of the maze is 11.8 m and its height is 2.6 m. The maze width varies between 0.9 and 1.1 m and therefore the cross-sectional area ranges between 2.34 m 2 and 2.86 m 2 [3]. To reduce the direct contribution of fusion neutron on the SW corner, several borated concrete shields were also installed.…”

“…Previous investigations show that the JET fusion neutron streaming calculations in SW maze entrance is a challenging task [1][2][3]. Two-step simulation approach including MC-MC and Deterministic-MC methods was a must in order to decrease the variances of calculated neutron flux and dose.…”

“…One of the aims of the DTE2 neutronics experiments is to investigate the Deuterium-Tritium (D-T) neutron streaming along the penetrations of biological shield of the JET Torus Hall. Continuous-energy Monte Carlo (MC) neutron transport calculations and TLDs measurements were already performed by international teams for the previous Deuterium (D-D) neutron streaming benchmark experiments around the JET maze entrance [1][2][3].…”