In:
MRS Proceedings, Springer Science and Business Media LLC, Vol. 757 ( 2002)
Kurzfassung:
The dissolution behavior and fission-product release from irradiated thoria-urania fuel was studied by immersing fuel samples in J-13 well water at 90°C. The samples are from the Shippingport Light Water Breeder Reactor and consist of binary solid solutions of (U,Th)O 2 with UO 2 contents varying from 2.0 to 5.2 Wt.%. The post-irradiation U isotopic composition of the samples used in our experiments is: 87.3% 233 U, 10.4% 234 U, 1.8% 235 U, and 〈 0.5% 238 U, 236 U, 232 U. Burn up values for the samples range from 22.3 to 40.9 megawatt-days per kg-metal. Our tests were performed on polished disks and on crushed and sieved samples in stainless-steel reaction vessels with air-filled head-space. After 196 days of reaction, samples showed no evidence for corrosion at the micrometer scale. Concentration ranges (μgL -1 ) of key radionuclides in filtered (∼5 nm pore size) leachates were: 0.1 – 15 90 Sr, 0.9 – 7.0 99 Tc, 0.1 – 35.2 137 Cs, 〈 0.2 – 0.8 233 U, 〈 0.1 – 0.7 232 Th. Concentrations of 237 Np, 239 Pu, 240 Pu and 241 Am were all 〈 0.2 μgL -1 . The relatively high concentrations of the fission products 90 Sr and 137 Cs occur early during leaching and decrease for later samplings. Matrix dissolution rates for the irradiated thoria-urania samples range from ∼3x10 -3 to 〈 3×10 -5 mg m -2 day -1 and are at least two orders of magnitude lower than those measured for UO 2 spent fuels under similar experimental conditions.
Materialart:
Online-Ressource
ISSN:
0272-9172
,
1946-4274
DOI:
10.1557/PROC-757-II9.3
Sprache:
Englisch
Verlag:
Springer Science and Business Media LLC
Publikationsdatum:
2002
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