The RITM-200N reactor represents a modification of a RITM-200 icebreaker reactor, which is designed on the basis of proven ship reactor construction technologies. The reactor plant is being developed for a ground-based SNPP power unit to be constructed on the territory of the Republic of Sakha (Yakutia). The article reflects the main results of developing the technical design of the RITM-200N reactor and completing a part of R&D in support of technical solutions. [ABSTRACT FROM AUTHOR]