Shutdown dose rate contribution from diagnostics in ITER upper port 18

• Published in: Fusion engineering and design 2016-11, Vol.109-111, p.736-741
• Main Authors: Cheon, M.S., Pak, S., An, Y.H., Seon, C.R., Lee, H.G., Bertalot, L., Krasilnikov, V., Zvonkov, A.
• Format: Article
• Language: English
• Subjects: Diagnostics; ITER; Shutdown dose rate; Upper port
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2016.02.009

•The Shutdown Dose Rate in the interspace of ITER upper port 18 was evaluated.•VUV spectrometer is the dominant contributor to the average SDR.•The existence and size of the blanket cooling pipes impacts significantly on SDR. D-T operation of ITER plasma will produce high-energy fusion neutrons those can activate materials around the place where human-access is necessary. The interspace of the diagnostic port is one of the area where human-access is necessary for the maintenance of diagnostic systems installed at the port, so it is important to evaluate a dose rate of the interspace area in order to comply with ALARA principle. The shutdown dose rate (SDR) in the interspace of ITER upper port 18 was evaluated by the Direct 1-Step (D1S) method using MCNP5 code. This port contains three diagnostics: Vacuum Ultra-Violet (VUV) Spectrometer, Neutron Activation System (NAS), and Upper Vertical Neutron Camera (UVNC). The contribution of each diagnostic in the port was evaluated by running separate upper port MCNP models those contain individual diagnostic only, and the total dose rate contribution was evaluated with the model which was fully integrated with all the diagnostics. The effect of the opening around the upper port plug and of the other ports was also investigated. The purpose of this assessment is to provide the shielding design basis for the preliminary design of the diagnostic integration in the port. The method and result of the calculation will be presented in this paper.