NRC Information No. 89-44: Hydrogen storage on the roof of the control room

During the Region V Chemistry Team Inspection at the Trojan Nuclear Plant the week of April 17, 1989, the inspectors identified a potential safety problem concerning the location of the hydrogen storage facility. Hydrogen is used on pressurized water reactor (PWR) plants for (1) providing a cover gas in the volume control tank, and (2) for cooling the main turbine generator. At boiling water reactor (BWR) plants, hydrogen is also used for cooling the main turbine generator and for injection into the feed system for plants which have implemented hydrogen water chemistry. The Trojan hydrogen storage facility is located on the control room roof which is 30-inch-thick reinforced concrete. The Trojan plant hydrogen facility does not meet guidelines from the standpoint of (1) the separation distance needed between a hydrogen pipe break and the control room ventilation intake to prevent buildup of a flammable or explosive gas mixture inside the control room, and (2) the separation distance needed to prevent damage to safety-related structures resulting from the explosion of an 8,000-scf hydrogen tank