On high level waste immobilization in y-al garnet-base cermet matrix under SHS conditions

4/04/2015 2015 - #01 Fuel cycle and nuclear waste management

Konovalov E.E. Lastov A.I. Nerozin N.A.

https://doi.org/10.26583/npe.2015.1.12

A method of high-level radioactive waste (HLRAW) radionuclides immobilization in a long-lasting Y-Al garnet matrix has been developed for their ultimate isolation from the environment. This matrix material is notable for endurance and high chemical resistance to natural media. Model systems containing Ce, Nd, Sm, Zr, Mo, 238U, and 241Am as simulators of HLRAW radionuclides were used in the work. An energy-saving technology of self-propagating high-temperature synthesis (SHS) with good technical, economical and environmental performance was applied for synthesizing the matrix material with the radionuclides-simulators fixed in the garnet structure. The results of X-ray phase analysis proved the formation of Y-Al garnet with strong inclusion of the simulating elements in its structure.

The produced synthetic mineral-like matrices are notable for high water-resistance. This property is confirmed by a low rate of 241Am leaching that is equal to 10–5 – 10–6 g/m2⋅day. A high strength of 241Am fixation in the Y-Al garnet structure is supplemented with a low value of americium carry-over at high temperatures of the synthesis that is caused by a short duration of the SHS.

It is recommended to apply the proposed novel method of HLRAW immobilization for developing a technology of ultimate processing of spent nuclear fuels of NPPs.

References

1. Holloway N. Atom, 1990, June, 404, p. 15.
2. Yudintsev S.V., Stefanovskij S.V., Chе S.. Izuchenie fazoobrazovaniya v sistemah Ca-Ce-Ti-Zr(Hf) – O dlya optimizatsii sinteza aktinidnyh matric na osnove pirochlora [Study of phase formation in Ca-Ce-Ti-Zr(Hf) – O systems for optimization of actinide matrices based on pyrochlore]. Fizika i himiya obrabotki materialov. 2008, no.3, pp. 70-80 (in Russian).
3. Lavyorov N,P., Yudincev S.V., Stefanovskiy S.V., Dzhang Ya.N. О novyh aktinoidnyh matritsah so strukturoy pirochlora [On new actinoid matrices with pyrochlore structure]. Doklady Akademii nauk. 2001, v. 381, no.3, pp. 399-402 (in Russian).
4. Меrkushkin А.О., Оchkin А.V., Rovnyj S.I., Stefanovskij S.V. Perovskit МI МIIО3 kak matritsa dlya vklyucheniya aktinidnoj fraktsii VAO [Perovskite МI МIIО3 as a matrix to include the actinide fraction of HAW]. Radiohimiya. 2009, v. 51, no. 2, pp. 170-174 (in Russian).
5. Burakov B.E., Аnderson Е.B., Zamoryanskaya М.V., Strykanova E.E., Yagovkina A.Ya. Sintez keramiki na osnove granata (Y, Gd, …)3 (Al, Ga)5O12 и perovskita (Y, Gd, …) (Al, Ga, …)O3 dlya immobilizatsii aktinidnyh оtkhodov slozhnogo chimicheskogo sostava [Ceramics synthesis based on garnet (Y, Gd, …)3(Al, Ga)5O12 and perovskite (Y, Gd, …) (Al, Ga, …)O3 to immobilize the actinide waste of complex chemical composition]. Voprosy radiatsionnoj bezopasnosti. 2000,no.1, pp. 11-14 (in Russian).
6. Коnovalov E.Е., Мishevec Т.О.,. Yudinсev S.V., Nikonov B.S., Boltoev Yu.D., Shulepov S.S. SVS- immobilizatsiya vysokoaktivnyh оthodov frakcii Аn-Tc v metallokeramicheskie matrichnye materialy [SHS-immobilization of high active waste of Аn-Tc fraction in ceramic-metal matrix materials]. Izvestiya vuzov. Yadernaya energetika. 2011, no.4. pp. 39-44 (in Russian).
7. Glagovskij E.М., Кuprin А.V., E.Е. Коnovalov, Pelevin L.P., Myshkovskij M.P., Dzekun E.G., Glagolenko Yu.V., Skobcev A.S. Sposob immobilizatsii vysokoaktivnyh оthodov – frakcii transplutonievyh i redkozemel’nyh elementov (varianty) [Method of immobilization for high active waste – fraction of trans-plutonium and rare-earth elements (versions)]. Patent RF № 2210824. Prioritet ot 17.07.2001. Zaregistrirovan v Gosudarstvennom reestre izobretenij RF. Моskva, 20 аvgusta 2003 (in Russian).
8. GOST R 25126-2003. Оthody radioaktivnye. Оpredelenie himicheskoj ustojchivosti оtverzhdyonnyh vysokoaktivnyh оthodov mеtodom dlitel’nogo vyschelachivaniya [Radioactive waste. Determination of chemical stability of high active waste solidified by the method of long-term leaching] (in Russian).
9. Federal’nye normy i pravila v оblasti ispol’zovaniya аtomnoj energii. Sbor, pererabotka, hpanenie i коndicionirovanie RAO. Trebovaniya bezopasnosti Federal standards and regulations in the field of atomic power engineering. Collection, processing, storage and conditioning of RAW. Safety regulations]. NP-019-2000. Моscow, 2000 (in Russian).

high level waste actinides immobilization self-extending high-temperature synthesis matrix materials

Link for citing the article: Konovalov E.E., Lastov A.I., Nerozin N.A. On high level waste immobilization in y-al garnet-base cermet matrix under SHS conditions. Izvestiya vuzov. Yadernaya Energetika. 2015, no. 1, pp. 111-118; DOI: https://doi.org/10.26583/npe.2015.1.12 (in Russian).