Corrosion Product Identification and Relative Rates of Corrosion of Candidate Metals in an Irradiated Air-Steam Environment

Abstract

Previously reported work by others indicates that dicopper trihydroxide nitrate, Cu2NO3(OH)3, forms on copper and copper alloys subjected to irradiated moist air near room temperature. We have performed experiments over a range of temperature and humidity, and have found that this species is formed at temperatures up to at least 150° C if low to intermediate relative humidities are present. At 150°C and 100% relative humidity, only Cu2O and CuO were observed. The relative general corrosion rates of the copper materials tested in 1-month experiments at dose rates of 0.7 and 2.0 kGy/h were Cu > 70/30 Cu-Ni > Al-bronze. High-nickel alloy 825 showed no observable corrosion.

Radiation Induced Corrosion of Copper in Anoxic Aqueous Solution

“…Despite the fact that the copper canisters will be exposed to ionizing radiation from the spent fuel, very few studies on radiation induced corrosion of copper have been reported. [10][11][12][13][14][15][16] Electrochemical studies of the influence of gamma radiation on copper have been performed in saline solutions with different outcome. 10,11,16 In two cases with dose rates of 0.014-0.063 kGy/h (1 Gy = 1 J/kg) and total doses of 1.4 kGy, in temperatures of 30 and 150 • C under anoxic conditions no corrosion effects could be seen.…”

“…13,14 With dose rates of 0.1-0.7 kGy/h and total doses of 107-510 kGy, relative humidity of 40-100% and temperatures of 90-150 • C, both cuprite (Cu 2 O) and tenorite (CuO) could be detected on the copper surfaces. 13,14 Radiation experiments on copper under oxic conditions in water at 42 • C and groundwater at 95 • C with dose rates of 1-6.5 kGy/h and total doses of 720-5 016 kGy resulted in pitting corrosion 12 and corrosion rates 30 times higher than in similar experiments without radiation. 15 It is interesting to note that in the two studies where no corrosion could be detected both dose rates and total doses are lower than in the studies where corrosion was detected.…”

Radiation Effects on Materials Used in Geological Repositories for Spent Nuclear Fuel

“…However, studies on radiation-induced corrosion of copper have been scarcely reported in the scientific literature [80][81][82][83][84][85][86]. Some studies have indicated that ionizing radiation increases the rate of corrosion of copper in contact with water, while other studies do not show any radiation effect.…”

Materials Degradation Issues in the U.S. High-Level Nuclear Waste Repository

“…Unfortunately, no studies of the influence of moist air radiolysis on Ti or Ni alloys have been performed. However, studies on the more corrosion susceptible Cu and Cu-Ni alloys showed that the influence of moist air radiolysis became negligible around a dose rate of -IO4 radihour [138,139], the maximum achievable dose rate on the waste package. For dose rates in this range N fixation (to produce N20, NOz, HN03) was observed in the gas phase without producing any significant effect on corrosion.…”