Post-Accident Hydrogen Generation and Control

Since all materials of construction are not compatible with spray solutions, an additional problem must be resolved. The corrosion of aluminum and zinc fabricated or coated components in a typical PWR plant when contacted with the sodium hydroxide in the alkaline sodium thiosulfate spray solution is a major contributor to post-accident hydrogen generation. When the hydrogen from metals corrosion is combined with the hydrogen generated from radiolytic decomposition of the coolant and the Zircaloy-water reaction of the overheated fuel cladding, hydrogen can reach a flammable concentration level in the reactor building within 1 to 2 months after a LOCA.