Investigations into Hydrazine Alternatives for Nuclear Steam Generators

Abstract

Nuclear water/steam-cycles worldwide are operated under alkalizing and reducing conditions. Regulators as well as environmental organizations strive for restrictions on the use of hydrazine or even a complete abandonment thereof due to its toxicity and mutagenic properties. Furthermore, a decrease in suppliers of nuclear grade hydrazine prompts supply shortages and supply chain disturbances of hydrazine. Framatome GmbH has investigated an approach regarding the operation of water/steam-cycles without hydrazine based on rapid radiation-induced oxygen scavenging using methanol. The radiation field in steam generators induces a radical chain reaction and, therefore, a reaction between methanol and oxygen. This replacement strategy is patented by New NP GmbH (predecessor of Framatome GmbH). The reducing properties of methanol in combination with radiation and different materials are studied by ECP measurements.

Based on the most recent results of experiments in radiation fields, Framatome considers this approach a valid strategy to replace hydrazine in the secondary side water/steam cycle to guarantee reducing conditions in the steam generator.