Abstract
The stability of β-Cs2U2O7 and SrZrO3, two possible phases of spent fuel elements, in hydrothermal fluids was investigated. β-Cs2U2O7 was unstable under hydrothermal conditions of 100, 200 and 300°C/300 bars releasing substantial amounts of its Cs in deionized water and all of its Cs in a bittern (high-Mg and-Ca) brine. SrZrO3 was found to be quite stable in deionized water but not in a bittern brine. For example, Sr released into solution decreased from 3.9 to 2.8% with an increase in temperature from 100 to 300°C probably because of better crystallization of SrZrO3 at higher temperatures. In bittern brine, 23.3, 94.9 and 100% of Sr was released into solution at 100, 200 and 300°C respectively as a result of acidic conditions generated by the hydrolysis of MgCl2 and formation of brucite. These results suggest that bittern brine which may be encountered in a salt repository is highly corrosive and may release all the Cs and Sr into solution under hydrothermal conditions if the containment were breached. The use of tailor-made overpacks or backfill barriers of highly stable and sorptive materials is essential especially in a salt repository in order to minimize the threat of highly hazardous Cs and Sr radionuclides finding their way into ground waters.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2833-2837 |
| Number of pages | 5 |
| Journal | Journal of Inorganic and Nuclear Chemistry |
| Volume | 43 |
| Issue number | 11 |
| DOIs | |
| State | Published - Jan 1 1981 |
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Hydrothermal stability of β-Cs2U2O7 and SrZrO3 in fluids. / Komarneni, Sridhar.
In: Journal of Inorganic and Nuclear Chemistry, Vol. 43, No. 11, 01.01.1981, p. 2833-2837.Research output: Contribution to journal › Article
TY - JOUR
T1 - Hydrothermal stability of β-Cs2U2O7 and SrZrO3 in fluids
AU - Komarneni, Sridhar
PY - 1981/1/1
Y1 - 1981/1/1
N2 - The stability of β-Cs2U2O7 and SrZrO3, two possible phases of spent fuel elements, in hydrothermal fluids was investigated. β-Cs2U2O7 was unstable under hydrothermal conditions of 100, 200 and 300°C/300 bars releasing substantial amounts of its Cs in deionized water and all of its Cs in a bittern (high-Mg and-Ca) brine. SrZrO3 was found to be quite stable in deionized water but not in a bittern brine. For example, Sr released into solution decreased from 3.9 to 2.8% with an increase in temperature from 100 to 300°C probably because of better crystallization of SrZrO3 at higher temperatures. In bittern brine, 23.3, 94.9 and 100% of Sr was released into solution at 100, 200 and 300°C respectively as a result of acidic conditions generated by the hydrolysis of MgCl2 and formation of brucite. These results suggest that bittern brine which may be encountered in a salt repository is highly corrosive and may release all the Cs and Sr into solution under hydrothermal conditions if the containment were breached. The use of tailor-made overpacks or backfill barriers of highly stable and sorptive materials is essential especially in a salt repository in order to minimize the threat of highly hazardous Cs and Sr radionuclides finding their way into ground waters.
AB - The stability of β-Cs2U2O7 and SrZrO3, two possible phases of spent fuel elements, in hydrothermal fluids was investigated. β-Cs2U2O7 was unstable under hydrothermal conditions of 100, 200 and 300°C/300 bars releasing substantial amounts of its Cs in deionized water and all of its Cs in a bittern (high-Mg and-Ca) brine. SrZrO3 was found to be quite stable in deionized water but not in a bittern brine. For example, Sr released into solution decreased from 3.9 to 2.8% with an increase in temperature from 100 to 300°C probably because of better crystallization of SrZrO3 at higher temperatures. In bittern brine, 23.3, 94.9 and 100% of Sr was released into solution at 100, 200 and 300°C respectively as a result of acidic conditions generated by the hydrolysis of MgCl2 and formation of brucite. These results suggest that bittern brine which may be encountered in a salt repository is highly corrosive and may release all the Cs and Sr into solution under hydrothermal conditions if the containment were breached. The use of tailor-made overpacks or backfill barriers of highly stable and sorptive materials is essential especially in a salt repository in order to minimize the threat of highly hazardous Cs and Sr radionuclides finding their way into ground waters.
UR - http://www.scopus.com/inward/record.url?scp=49149134247&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=49149134247&partnerID=8YFLogxK
U2 - 10.1016/0022-1902(81)80626-4
DO - 10.1016/0022-1902(81)80626-4
M3 - Article
AN - SCOPUS:49149134247
VL - 43
SP - 2833
EP - 2837
JO - Polyhedron
JF - Polyhedron
SN - 0277-5387
IS - 11
ER -