Estimation of Radioactivities in the IFMIF Liquid Lithium Loop Due to the Erosion and Corrosion of Target Back-Wall

Large amount of radioactive erosion and corrosion products are produced in the IFMIF lithium loop in addition to the deuteron-lithium reaction remnant ⁷Be. An analysis was conducted to estimate the radioactive corrosion products with a design code ACT-4 developed in JAERI, the activation cross sections based on the FENDL library and the IEAF-2001 library, the latest version of nuclear activation data in the intermediate energy range up to 150 MeV. The result says the concentration of the corrosion in lithium is not very large compared with that of ⁷Be. However, the behavior of the nuclides such as accumulation and detachment on material has not been clarified yet. When the dose rate around the lithium loop was estimated under the condition of 100% plate-out, the value was beyond the acceptable level for the hands-on maintenance near the loop soon after the operation stop. It means that a very efficient cold trap is required so that the 90% activity in the lithium loop is removed.