Study of melted Synroc doped with simulated high-level waste

Book · Wed Dec 31 04:00:00 EST 1997

OSTI ID:572084

Sobolev, I A; Stefanovsky, S V ^[1]; Ioudintsev, S V; Nikonov, B S; Omelianenko, B I; Mokhov, A V ^[2]

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1. SIA Radon, Moscow (Russian Federation)
2. Inst. of Geology of Ore Deposits, Moscow (Russian Federation)

Preparation and characterization of inductively-melted Synroc containing 20 wt% simulated plant Mayak reprocessing waste were performed. The sample bulk composition was as follows, (in wt.%): 55.4 TiO{sub 2}, 15.8 ZrO{sub 2}; 7.5 CaO; 7.4 BaO; 4.3 Al{sub 2}O{sub 3}; 2.0 MnO; 1.8 SiO{sub 2}; 0.7 Na{sub 2}O; 1.9 K{sub 2}O; 0.5 Ce{sub 2}O{sub 3}; 1.0 UO{sub 2}; 0.9 NiO; 0.6 Cr{sub 2}O{sub 3}, and 0.2 FeO. The sample was produced by melting in air at 1,550--1,600 C under barometric pressure. It is composed of a few crystalline phases and a minor glass phase. Most of the phases (hollandite, zirconolite, perovskite and rutile) are similar to the analogous phases found in the other Synroc formulations. An additional phase with average composition, wt.%: 59.8 TiO{sub 2}; 15.6 CaO; 7.0 UO{sub 2}; 5.6 ZrO{sub 2}; 4.7 MnO; 4.1 Ce{sub 2}O{sub 3}, and 1.8 Al{sub 2}O{sub 3} was found. Some elements (Ba, Si, Ni, K, Na, Fe) were present in the phase in negligible quantities. Its formula (Ca{sub 2.65}U{sub 0.3}Ce{sub 0.2})(Ti{sub 7.3}Mn{sub 0.6}Zr{sub 0.4}Al{sub 0.3})O{sub 20.0} is rather close to a rare mineral uhligite--Ca{sub 3}(Ti,Zr,Al){sub 9}O{sub 20}. Another possible counterpart of the phase is murataite-like mineral previously described in tailored ceramic designed for Savannah River Plant wastes fixation. This phase as well as zirconolite are the major host for U in the sample. Preliminary data on the material leachability in water at 350 C and 50 MPa have been obtained. Uranium contents in the solution were about 1 ppb and close to the uranium dioxide solubility in deionized water under the same P-T conditions.

• OSTI ID: 572084
• Report Number(s): CONF-961202--
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
36 MATERIALS SCIENCE
CHEMICAL COMPOSITION
CORROSION RESISTANCE
EXPERIMENTAL DATA
FABRICATION
LEACHING
PHASE STUDIES
SYNROC PROCESS
SYNTHETIC ROCKS
WASTE FORMS