Rotary plug seal

Purpose: To enable solidification for freeze seal alloys with no troubles even in forced cooling and prevent cover gas leakage in shielding plugs of LMFBR type reactors. Constitution: A cooling channel is provided in the side wall of a freezing metal basin of a freezing seal mechanism provided between a rotary plug and a stationary plug. A gas discharge tube is provided to the upper portion and a gas charge tube is provided to the lower portion of the cooling channel. Cooling medium is introduced through the gas charge tube into the cooling channel and discharged through the discharge tube at the upper portion. The inside of the cooling channel is divided into a plurality of chambers by partition plates, so that cooling medium intorduced into the gas charge tube in the lower portion may gradually rise to the upper portion. Accordingly, the seal alloy is cooled from the lower portion, whereby solidification proceeds from the lower to the upper portions. Consequently, peelings or cracks due to shrinkage upon solidification can be prevented. (Ikeda, J.)