Thermal Analysis and Immobilisation of Spent Ion Exchange Resin in Borosilicate Glass

Abstract

The underground disposal of waste arising from the nuclear industry needs constant evaluation in order to improve upon it through minimizing the volume and cost by reducing the amount of glass used without compromising the safety of any leakage from the radioactive waste form. The immobilization of the spent resin (NRW-40) in borosilicate glass was investigated to meet the acceptance criteria for disposal of nuclear waste. The organic mixed bed resin in granular form was used as a waste target. The analysis of surrogate resin doped with radioactive and non-radioactive cesium (Cs) and cobalt (Co) was carried out to investigate their thermal and chemical properties and their compatibility with an alkaline borosilicate glass. The thermal analysis indicates that the structural damage caused by 1 mSv gamma radiation to the radioactive resin has altered its properties in comparison with the non-radioactive resin, same amount of cesium (8.88 wt%) and cobalt (1.88 wt%) were used in both resins. The immobilization of residue shows that the excess sulfur in the residue caused phase crystallization in the final glass matrix. It was found that the volatilization of Cs-137 and Co-60 from the successful radioactive resin-glass matrix (HG-3-IER-500) were more than that in the non-radioactive resin-glass matrix (HG-3-IEX-500). The study demonstrates comprehensive experimental and analytical works and shows that it is possible to minimise the volume of the waste while keeping the required safety levels, however further research needs to be carried out in this area

Cobalt and nickel uptake by silica-based extractants

“…Techniques such as dewatering, pyrolysis and stripping may reduce the category of the resin waste, for example from high level waste to intermediate or low level waste, but may generate a quantity of highly active waste that must be separately treated. [28][29][30][31] In the United Kingdom, currently the preferred option for high level radioactive waste disposal is vitrification within a borosilicate matrix and long-term storage (potentially thousands of years) of the glass-based waste form. [32] As mentioned above, one potential advantage of silica-based resins lies in their ability to be thermally treated.…”

Solidification of radioactive waste resins using cement mixed with organic material

“…The leachates were analysed using gamma spectrometer. From the analysis results on radioactivity of leachates, the cumulative fraction release (CFR) and the effective diffusivity (D) were calculated as follows: CFR = ∑an / A0 (1) where, CFR is cumulative fraction release, ∑an is the cumulative quantity of a nuclide released from the specimen from the beginning of the first leaching interval to the end of leaching interval of concern, corrected for radioactive decay. The effective diffusivity was calculated by the following equation:…”

“…Ion exchange resins are generally no longer effective after a certain cycles of usage. The regeneration of these spent resins using acid leaching technique to remove radionuclides is not economical compare to replacing with new resins [1]. Usually these radioactive waste resins are rinsed out from their column and are often stored in drums prior to disposal.…”

Efficient immobilization of ionic corrosion products by a silica-hydroxyapatite composite via a cold sintering route

“…The spent ion exchange resin, which is produced from nuclear power facilities installed worldwide, is more than 3500 m 3 per year. 1,4,5 The future of radioactive waste (RW) generated as a result of nuclear reactor operations has not been properly and effectively addressed. RW is generated in various ways, such as mining and fuel processing activities, spent fuel assemblies, ion exchange resins (IER), 6,7 radioisotope production laboratories, 8 and other sources (membrane process, evaporator, and lters, etc.).…”