The conceptual design activity of the LHD-type helical reactor FFHR-d1 is being intensively conducted under the Fusion Engineering Research Project FERP at NIFS.The present activity incorporates the machine parameters determined in the “1st-round” design,examined in the detailed physics analysis of the core plasma performance and in the three-dimensional analyses of the in-vessel components in the “2nd-round” design.The present “3rd-round” design focuses on the construction and maintenance procedure.