Speaker
Geon-Woo Kim
(Nuclear Engineering)
Description
Tokamak reactors like ITER or fusion DEMO reactors have serious concerns about material damages to plasma facing components (PFC) due to plasma instabilities. Plasma disruptions, such as vertical displacement events (VDE), with high heat flux can cause melting and vaporization of plasma facing materials and also burnout of coolant channels. In addition, high thermal stresses due to rapid changes of temperature can degrade the integrity of PFCs like first wall of blanket module. In order to simulate melting or vaporization of first wall in blanket module when VDE occurs, one-dimensional heat conduction equations were solved numerically with modification of the specific heat of the first wall materials using effective heat capacity method. Also, a nuclear reactor thermal-hydraulic analysis code, MARS-KS, was adopted for solving hydrodynamics in coolant channels and heat equations in other components of blanket except first wall due to its prediction capability for two-phase flow and critical heat flux (CHF) value in coolant channels. A water-cooled breeding blanket concept was selected for simulation target according to the conceptual design of the Korean fusion demonstration reactor (K-DEMO) proposed by the National Fusion Research Institute of Korea. It includes 7 mm thick first wall as plasma facing components which consists of 5 mm thick tungsten, 1 mm thick vanadium, and 1 mm thick reduced activation ferritic/martensitic (RAFM) steel. Two VDE simulation conditions were selected for first wall heat flux values of 600 MW/m22 (0.1 sec) and 200 MW/m22 (0.3 sec). Simulation result showed that temperatures of tungsten, vanadium, and RAFM steel exceeded each melting temperatures so that 1.55 mm thick tungsten was melted as maximum and also burnout of coolant channel occurred.
Co-authors
Geon-Woo Kim
(Nuclear Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, South Korea)
Goon-Cherl Park
(Nuclear Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, South Korea)
Hyoung-Kyu Cho
(Nuclear Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, South Korea)
Jeong-Hun Lee
(Nuclear Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-744, South Korea)
Kihak Im
(National Fusion Research Institute, 169-148, Yuseong-gu, Daejeon 305-806, South Korea)
