Hydrazine and Hydrogen Co-injection to Mitigate Stress Corrosion Cracking of Structural Materials in Boiling Water Reactors, (I) Temperature Dependence of Hydrazine Reactions

Hydrazine and hydrogen co-injection into reactor water is considered a new mitigation method of stress corrosion cracking in BWRs. Fundamental data such as the thermal decomposition of hydrazine, the reaction of hydrazine with oxygen and with hydrogen peroxide at temperatures ranging from 150 to 280°C are needed to evaluate suitability of this method. Reactions in bulk water were studied in a polytetrafluoroethylene pipe to separate surface reaction effects. The results were as follows. (1) The orders of the apparent reaction rate of hydrazine with oxygen were 1 and 0.5 for hydrazine and oxygen concentrations, respectively . Arrhenius parameters were k 0=69.0 s−1.μM−0.5 and (2) The orders of apparent reaction rate of hydrazine with hydrogen peroxide were each 0.5 for hydrazine and hydrogen peroxide concentrations kC 0.5 N2H4 C 0.5 H2O2 . Arrhenius parameters were k 0=1.42x 106 s−1, Ea =78.8 kJ.mol−1. Based on these data, the applicability of hydrazine and hydrogen co-injection into BWRs was considered. Hy...