The effects of radiation on the retention of strontium in zeolite-NaSrY

Abstract

A new experimental method has been developed to measure the release of radionuclides from radiationdamaged materials using a combination of 500 keV H z beam irradiation, electron microscopy, and electron microprobe analysis techniques. A good correlation between the radiation damage and changes in the release of radionuclides from irradiated zeolite-Y preloaded with Sr has been established. After irradiation with a 500 keV H z beam to a dose of 3.6 6 10 17 ions cm 22 , the release of Sr in 1 N NaCl, 1 N CaCl 2 and 10 mN AgNO 3 solutions was reduced by a factor of up to seven in the radiation-damaged material. A comparison of results obtained in 10 mN AgNO 3 solution with that of 1 N CaCl 2 solution showed that structural damage occurred not only to the supercages, but also to the small cages, i.e. sodalite cages and double 6-ring prisms. When the radiation dose was above 2.5 6 10 10 Gy, the ion exchange of the large cations (Ca and Sr) was completely stopped, whereas the small cation-exchange (Ag and Na) could still proceed. A leach test in the deionized water showed that amorphization of zeolite-NaSrY can reduce the release of the adsorbed radionuclides, Sr, from 0.23 mg g 21 for crystalline zeolite-NaSrY to 0.12 mg g 21 after 234 h of leaching in 90 uC deionized water.

Preparation and Properties of Hydroceramic Waste Forms Made with Simulated Hanford Low‐Activity Waste

“…The thermal stability study of zeolite A shows that it is stable at very high temperatures around 1000°C should some temperature anomaly occur in the distant future, 11 the structure remains intact. The effect of radiation on the release of the adsorbed radionuclides from LAW waste form is not a problem but radiation damage is 16,17 . They found that, although the radiation destroys the long‐range order of the zeolite, the collapse of the large cages in the zeolite structure helps to trap and hold radionuclides such as Sr and Cs, thus retarding their release into the biosphere.…”

Cesium leaching from γ-irradiated CsA and CsX zeolites

“…These species appear with gamma irradiation and they are due to the presence of small alumina particles or aluminum and oxygen dangling radicals [17]. It would be a local amorphization similar to the one proposed by Acosta [18] and Gu et al [12,19,20] when zeolites are irradiated with an electron beam. Note that, although we found consistence with the results of Acosta and Gu, they used smaller ionizing doses and the nature of radiation was different.…”

Spent fuel canister for geological repository: Inner material requirements and candidates evaluation

“…They are also very resistant to corrosion and can withstand high temperatures without their properties being affected. Additionally, many studies showed their high absorption efficiency and retention capabilities toward some key radioactive elements, such as caesium [90][91][92][93][94][95][96], iodine [35,97], thorium [98][99][100][101][102][103][104], uranium [104][105][106][107][108], radium [105,109] or plutonium [96,110], and other elements like technetium [96], americium [96,111] or strontium [91][92][93][94][95]112].…”