Vent valve, absence

Reliability is enhanced by complete absence of gas valves. Maximum safety is achieved without depending upon pressure relief valves or exploston discs. Wide open burner design would relieve any abnormally elevated pressure directly into the boiler which in turn is directly vented to atmosphere. 

Failure to remove excess reaction ECH from the system prior to condensate addition was due to the absence of cooling water flow to the ECH/water condenser. The cooling water system for the condenser had not been commissioned after the plant shutdown, and was isolated both at a manually operated valve and at a valve operated via the plant computer. The lack of condensing capacity resulted in high vapour flows to vent, with a consequent increased back-pressure on the reactor which caused a reduced evaporation rate. 

Absence of a solid partition between the valve and the vent ... 

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