Cover gas seal device for lifting core upper mechanism

摘要

PURPOSE:To simplify substitute operation for air for preventing diffusion into the upper space on a rotating plug of activated inactive gas by forming a cover gas seal device for fast breeder composed of a radiation shielding body, a bellows and a seal ring. CONSTITUTION:The lower end of a cylindrical radiation shield body 15 for enclosing the upper half part of an elevating reactor core upper mechanism 10 is airtightly and detachably installed on a rotating plug 12. A bellows 17 formed of a cover gas seal device 16 together with the shield body 15 is arranged in the inside of the shield body 15, and the upper end thereof is airtightly attached to the upper end of the inside of the shield body 15. A seal ring 18 is airtightly and detachably attached to the middle part of the outside of a mechanism 10 and the inside of the lower end of the shield body 15b on the lower end of the bellows 17. Thereby radiated inactive gas is sealed between the bellows 17 and the shield body 15 when the mechanism 10 is detached. Sodium vapor which is contained in radiated inactive gas in the time in which the mechanism 10 is elevated is prevented from being deposited on the upper half of the mechanism 10 by attaching the seal ring 18.