Effect of feed composition on the production of off-gases during vitrification of simulated low-activity nuclear waste

0577176 - ÚSMH 2024 RIV GB eng J - Journal Article
Kunc, J. - Kloužek, Jaroslav - Vernerová, Miroslava - Cincibusová, Petra - Ferkl, P. - Hall, M.A. - Eaton, W.C. - Hrma, P. - Guillen, D.P. - Kruger, A.A. - Pokorný, Richard
Effect of feed composition on the production of off-gases during vitrification of simulated low-activity nuclear waste.
Progress in Nuclear Energy. Roč. 166, DEC (2023), č. článku 104932. ISSN 0149-1970. E-ISSN 1878-4224
Institutional support: RVO:67985891
Keywords : Glass melting * Hazardous emissions * Modeling * Nuclear waste * Waste vitrification
OECD category: Ceramics
Impact factor: 2.7, year: 2022
Method of publishing: Limited access
https://doi.org/10.1016/j.pnucene.2023.104932

During the vitrification of nuclear waste, hazardous and radioactive emissions are generated from the feed-to-glass conversion reactions, in addition to discharges from forced air bubbling and air inleakage. Although the major gaseous emissions are water vapor, nitrogen, and carbon dioxide, various monitored environmental pollutants are also released, such as nitrogen oxides or sulfur dioxide. In addition, reactions between organics and nitrates in the feed may also form products of incomplete combustion such as carbon monoxide and acetonitrile. Although off-gas emissions are commonly measured during both laboratory- and pilot-scale melter testing, no predictive tool is currently available to a priori estimate the composition of gaseous emissions during nuclear waste vitrification. This work forms a basis for the development of such predictive tool by measuring gas evolution from a broad range of simulated low-activity waste melter feeds using evolved gas analysis data and developing correlations between the feed and off-gas compositions. Using reaction stoichiometry and regression analysis, we demonstrate that next to the content of nitrogen and organic carbon in the feed, the gaseous emissions are affected by the feed reduction-oxidation conditions – the more the feed is reduced, the less nitrogen monoxide, and more carbon monoxide and acetonitrile evolves. The results presented in this work provide a first step towards reducing the amount of expensive physical melter testing and the regression analysis provides a simple tool for rapid optimization of feed composition with respect to off-gas composition.
Permanent Link: https://hdl.handle.net/11104/0348801