Piping configuration, hazards

Highlights potential hazards from adjacent nonrelated systems (e.g. heating pipes near sensitive electronic equipment, hot air leaks, drips from pipes, multichannels throngh same connectors, EMI effects on multichannel configurations, etc.). 

Redundant 28 cfm vacuum pumps located in the Zone. 1 filter room of the MER, shown in Figure 2.5-10, evacuate a 80-gallon (10.7-cubic feet) tank to supply system vacuum. The pumps are configured to automatically start to maintain system vacuum at a prescribed level. The exhaust from the pumps is routed into the Zone 1 exhaust upstream of the Zone 1 charcoal filters. Two-inch welded stainless steel piping is routed from the vacuum tank in the MER through the overhead in Rooms 112 and 111 into the Zone 2A canyon. In the canyon, the vacuum line is routed to a cold trap that will condense radioactive effluents that are drawn into the vacuum system. Two-inch welded stainless steel tubing is used to route process vacuum to each SCB. While the pumps themselves are not identified as important to safety, the routing of the pump exhaust to the Zone 1 exhaust is so identified, because it assures appropriate filtration of the effluent in the event that hazardous constituents are drawn into the system. 

Dual-containment piping A configuration where an exterior pipe surrounds the supply pipe, which carries a high purity or hazardous gas or liquid. The outer volume can be evacuated and monitored for safety. 

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