Oxidation and vitrification of aluminum with lead borate glass for low level radioactive waste treatment

In this work, the possibility of using electrodialysis for the treatment of liquid low-level radioactive waste was investigated. The first aim of the research was to evaluate the influence of the process parameters on the treatment of model solutions with different compositions. Subsequent experimental tests were conducted using solutions containing selected radionuclides (60Co and 137Cs), which are potential contaminants of effluents from nuclear power plants, as well as components often found in waste generated from industrial and medical radioisotope applications. The results of the experiments performed on real radioactive waste confirmed that electrodialysis was a suitable method for the treatment of such effluents because it ensured high levels of desalination and rates of decontamination. The most important parameters impacting the process were the applied voltage and electrical current. Moreover, this research shows that the application of the ED process enables the separation of non-ionic organic contaminants of LLW, which are unfavorable in further stages of waste predisposal.

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Adsorption Properties of Sr(II) on Zeolite Type Adsorbents and Their Irradiation Stabilities

Volume 4: Radiation Protection and Nuclear Technology Applications; Fuel Cycle, Radioactive Waste Management and Decommissioning; Computational Fluid Dynamics (CFD) and Coupled Codes; Reactor Physics and Transport Theory ◽

10.1115/icone22-30329 ◽

2014 ◽

Author(s):

Hitoshi Mimura ◽

Shunsuke Susa ◽

Yoshiyuki Ito ◽

Yasuo Saito ◽

Minoru Matsukura

Keyword(s):

Radioactive Waste ◽

Flow Rate ◽

Breakthrough Curve ◽

Waste Treatment ◽

Adsorption Properties ◽

Mixed Solution ◽

Low Level ◽

Single Solution ◽

Type Zeolite ◽

Radioactive Waste Treatment

Radioactive waste treatment is planned in LWTF (Low-level radioactive Waste Treatment Facility, JAEA) for LLW generated from the Tokai-reprocessing facility. The target LLW consists of highly concentrated sodium nitrate (5 M NaNO3) containing low-level 90Sr. In this study, selective adsorption properties of Sr2+ for highly functional A type zeolites (A51-JHP, A51-J (Union Showa) and A-4, X type zeolite (F-9) and Titanic acid-PAN (polyacrylamide) were clarified by batch and column adsorption methods. The irradiation stabilities of these adsorbents were also evaluated. The distribution properties of Sr2+ on different adsorbents were compared in simulated waste solution (5 M NaNO3, 0.1 ppm Sr2+, 85Sr as tracer). The order of distribution coefficients (Kd,Sr) was Titanic acid-PAN > A51-JHP > A51-J > A-4 > F-9. The largest value of Kd,Sr for titanic acid-PAN was estimated to be 218 cm3/g, while the saturated capacity (Qmax) was very small. Titanic acid-PAN had also the largest uptake rate of Sr2+ ions and the uptake attained equilibrium within 8 h. On the other hand, A51-JHP had a relatively large Kd,Sr value above 100 cm3/g and a Qmax value of 0.65 mmol/g. The breakthrough properties of Sr2+ were examined by varying cations present (single and mixed solutions) and flow rate (0.08 and 0.17 cm3/min). The components for the single solution were 400 g/L NaNO3, 100 ppm Sr2+, 85Sr as tracer, and the mixed solution contains 200 ppm Cs+, 100 ppm Ca2+, 50 ppm Mg2+, 50 ppm RuNO3+ in addition to the single solution components. The breakthrough curve for Titanic acid-PAN column using single solution had an S-shaped profile, while the “concentration phenomenon” exceeding C/C0 (breakthrough ratio) = 1 was observed in the case of mixed solution. As for the A51-JHP column, the breakthrough curve for single solution was similar to that for mixed solution and the 5% breakpoint was enhanced by decreasing the flow rate. The A51-JHP was stable under 60Co-irradiation up to 2.54 MGy; Kd,Sr and Qmax values were almost constant. In contrast, Titanic acid-PAN was affected above 0.28 MGy, due to the radiolysis of PAN matrix, and this surface alteration led to the release of active component of titanic acid. The novel A type zeolite (A51-JHP) is thus expected for the selective removal of Sr2+ in LWTF. The optimization of particle size and flow rate should be examined before practical use.

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Recharge to low-level radioactive-waste burial trenches 11 through 14, West Valley, New York

Open-File Report ◽

10.3133/ofr79990 ◽

1979 ◽

Author(s):

David E. Prudic

Keyword(s):

New York ◽

Radioactive Waste ◽

Low Level ◽

Low Level Radioactive Waste

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