29th Symposium on Fusion Technology (SOFT 2016)

P2.074 Spatial Distribution of Accumulated Neutron Emission in KSTAR

6 Sep 2016, 14:20

1h 40m

Foyer 2A (2nd floor), 3A (3rd floor) (Prague Congress Centre)

Board: 74

Poster D. Diagnostics, Data Acquisition and Remote Participation P2 Poster session

Speaker

Youngseok Lee (KSTAR Research Center)

Description

Long-pulse D-D plasma operation in the annual KSTAR plasma campaign is performed and involved Ohmic heating and auxiliary heating such as a neutral beam injection (NBI) of high power with deuterium beams. The NBI heating power reached up to 6 MW at the moment. In addition, many energetic runaway electrons are also observed through hard-X ray (HXR) monitoring during the operation. Runaway electrons of high energies can be high enough to produce photonuclear reactions in the walls from photo-nuclear processes. The photonuclear reactions due to runaway electrons with energies up to ~ 20 MeV are observed in the 2010 KSTAR plasma campaign. The intent of this study is to investigate its spatial distribution in accumulated neutron production in KSTAR. To carry out the work, four natural nickel (Ni) samples are installed inside the KSTAR vacuum vessel. The spatial distribution of accumulated neutron emission in KSTAR is determined by using neutron rates obtained from the samples based on activation analyses. The resulting measured neutron rates have anisotropic spatial distribution inside the KSTAR vacuum vessel. It appears that neutron production in the vacuum vessel is not only due to D-D beam -plasma reactions, and that both the NBI and the high energy X-rays could be attributed to neutron production from KSTAR. There is need to estimate factors influencing to neutron production in KSTAR for further study. More details will be presented. [1] A.C. England, et al., Phys. Lett. A, 375, 3095, (2011) [2] J.G. Kwak, et al., to be published in Fus. Eng. Des. (2016) /dx.doi.org/10.1016/j.fusengdes.2016.02.037