Kim Hyunduk, Lee Hee-Seock, Hong Sukmo, Kim Minho, Chung Chinwha, Kim Changsuk
Pohang Accelerator Laboratory, POSTECH, Pohang 790-784, Korea.
Radiat Prot Dosimetry. 2005;116(1-4 Pt 2):24-7. doi: 10.1093/rpd/nci242.
The deuterium-deuterium (D-D) reaction in the KSTAR (Korea Superconducting Tokamak Advanced Research) tokamak generates neutrons with a peak yield of 2.5 x 10(16) s(-1) through a pulse operation of 300 s. Since the structure material of the tokamak is irradiated with neutrons, this environment will restrict work around and inside the tokamak from a radiation protection physics point of view after shutdown. Identification of neutron-produced radionuclides and evaluation of absorbed dose in the structure material are needed to develop a guiding principle for radiation protection. The activation level was evaluated by MCNP4C2 and an inventory code, FISPACT. The absorbed dose in the working area decreased by 4.26 x 10(-4) mrem h(-1) in the inner vessel 1.5 d after shutdown. Furthermore, tritium strongly contributes to the contamination in the graphite tile. The amount of tritium produced by neutrons was 3.03 x 10(6) Bq kg(-1) in the carbon graphite of a plasma-facing wall.
韩国超导托卡马克先进研究装置（KSTAR）中的氘-氘（D-D）反应通过300秒的脉冲运行产生峰值产额为2.5×10¹⁶ 秒⁻¹ 的中子。由于托卡马克的结构材料受到中子辐照，从辐射防护物理学角度来看，这种环境在停机后将限制在托卡马克周围及内部开展工作。为制定辐射防护指导原则，需要识别中子产生的放射性核素并评估结构材料中的吸收剂量。通过MCNP4C2和一种存量代码FISPACT评估活化水平。停机1.5天后，内真空室工作区域的吸收剂量以每小时4.26×10⁻⁴ 毫雷姆的速率下降。此外，氚对石墨瓦中的污染有很大影响。面向等离子体壁的碳石墨中，中子产生的氚量为3.03×10⁶ 贝克勒尔每千克。
