Hydrazine Radiolysis by Gamma-Ray in the N2H4–Cu+–HNO3 System

• Published in: International journal of molecular sciences Vol. 22; no. 14; p. 7376
• Main Authors: Chang, Naon, Won, Huijun, Park, Sangyoon, Eun, Heechul, Kim, Seonbyeong, Seo, Bumkyung, Kim, Yongsoo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 09.07.2021; MDPI
• Subjects: copper ion; Decomposition; Decomposition reactions; Decontamination; Gamma rays; Hydrazine; Hydrazines; Intermediates; Ions; irradiation; nitrate ion; Nuclear power plants; Radiation; Radiation dosage; Radicals; Radiolysis; Spectroscopy; γ-ray
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22147376

Radiolysis of chemical agents occurs during the decontamination of nuclear power plants. The γ-ray irradiation tests of the N2H4–Cu+–HNO3 solution, a decontamination agent, were performed to investigate the effect of Cu+ ion and HNO3 on N2H4 decomposition using a Co-60 high-dose irradiator. After the irradiation, the residues of N2H4 decomposition were analyzed by Ultraviolet-visible (UV) spectroscopy. NH4+ ions generated from N2H4 radiolysis were analyzed by ion chromatography. Based on the results, the decomposition mechanism of N2H4 in the N2H4–Cu+–HNO3 solution under γ-ray irradiation condition was derived. Cu+ ions form Cu+N2H4 complexes with N2H4, and then N2H4 is decomposed into intermediates. H+ ions and H● radicals generated from the reaction between H+ ion and eaq− increased the N2H4 decomposition reaction. NO3− ions promoted the N2H4 decomposition by providing additional reaction paths: (1) the reaction between NO3− ions and N2H4●+, and (2) the reaction between NO● radical, which is the radiolysis product of NO3− ion, and N2H5+. Finally, the radiolytic decomposition mechanism of N2H4 obtained in the N2H4–Cu+–HNO3 was schematically suggested.