UNDERGROUND NUCLEAR POWER STATION AND ITS SERVICING PROCEDURES Russian patent published in 2003 - IPC

FIELD: nuclear power engineering; nuclear power stations disposed in underground shelters. SUBSTANCE: underground nuclear power station designed for multiple reuse of underground shelters to dispose therein substitute power units has identical power units made in the form of modules around shipboard equipment and using shipboard technologies; each module incorporates reactor unit and power conversion unit joined thereto, as well as energy carrier transport system; reactor units are mounted in underground horizontal shelters provided with vertical cavities; underground shelters are made in the form of single-level galleries mounting on one end power unit and provided on the other end with additional free space whose length equals minimum three lengths of reactor unit; each of the latter is joined to respective conversion unit through cofferdam. Power plant servicing procedures include running power unit at full power in underground horizontal galleries; closing down power units involving extraction of spent nuclear fuel from reactor units followed by its disposal for recovery; disconnecting power units whose service life has expired from power conversion units followed by their laying-up and storage; removing power conversion units for refueling; installing new power units and accelerating them to gain full power. Full-power operation of power units is effected in underground galleries provided with additional space and extraction of spent fuel from reactor units whose service life has expired when closing down underground power unit is made directly in underground galleries; then reactor units whose service life has expired are given laying-up treatment and placed in storage in additional spaces of same galleries; after extraction of spent nuclear fuel from reactor units and disconnection of the latter from power conversion units being removed these reactor units are pushed deep into additional space to clear room for installing new power units; this cycle of replacing power units whose life has expired by new ones is repeated until entire free length of storage gallery is filled up. EFFECT: enhanced radiation and environmental safety of power station in storage and closing-down; reduced time and labor consumption for replacing old power units by new ones. 2 cl, 3 dwg