Sorption Charecterization of Radonuclides on Clays in Yucca Mountain Alluvium

Ding, M. ; Reimus, P.W. ; Chipera, S. ; Scism, C.

United States. Department of Energy. Yucca Mountain Project Office.

关键词: Actinides;    Clays;    Isotherms;    Radioisotopes;    Yucca Mountain;   

DOI  :  10.2172/893924
RP-ID  :  NA
RP-ID  :  NA
RP-ID  :  893924

美国|英语

来源: UNT Digital Library

【 摘 要 】

Sorption of {sup 237}Np(V) and {sup 233}U(VI) was measured on clays separated from Yucca Mountain alluvium as a function of solution pH and aqueous actinide concentrations. The results indicate that sorption of U and Np on the separated clay fraction depends strongly on solution pH. Np sorption on clays increases slowly with increasing pH from 3 to 7. Above pH 7, Np sorption on clays increases rapidly up to a pH of about 10. On the other hand, U sorption on clays reaches it maximum at a pH of about 6, with sorption decreasing as pH increases from 6 to 8 and then increasing again as pH increases further from 8 to about 10. The results suggest that a Freundlich isotherm can be used to describe U and Np sorption on clays at pH above 5.5. The results of this study indicate that clay minerals play a very important role in the sorption of U and Np on Yucca Mountain alluvium. Indeed, the clay content of the alluvium is probably considerably more important than water chemistry in predicting the ability of the alluvium to attenuate the transport of these radionuclides.