English to Czech Tech/Engineering Energy / Power Generation Nuclear

Součást parogenerátoru jaderné elektrány. Další kontext bohužel není. Jinde lze najít například toto:

"Many utilities use nozzle dams inside their steam generators to isolate the primary channel head from the refuelling pool, allowing eddy current testing or repair of the tubes to be carried out simultaneously. NES nozzle dams are designed to fit into nozzles of diameter 30-42in (760-1070mm). The only access into the steam generator channel head is through a manway opening, typically 16in (406mm) wide and the NES dams are segmented to allow passage through this opening. There are high dose rates and contamination levels in the channel head so to meet ALARA objectives the dam must be rapidly installed, and sealed with zero leakage.

The most common type of installed retention ring in both Westinghouse and Framatome-designed PWRs is a flange ring with 20 threaded holes. The usual method for sealing the nozzle has been to use a folding bulkhead bolted against a compression seal applied to the top surface of this flange ring. NES’s Type-WR nozzle dam was developed to seal SG nozzles with these flange rings. The dam, which seals within the smooth inner diameter of the flange ring, consists of two rugged pneumatic seals and a third passive seal secured to eight of the 20 flange ring threaded holes. By using dissimilar materials, special thread configurations and other measures, the galling problems experienced with dams which are sealed at the top surface of the flange ring and use standard threaded connections have been eliminated."

http://www.neimagazine.com/features/featureat-the-service-of...