Environmental behavior of hafnium : the impact on the disposition of weapons-grade plutonium
Name
48749603-MIT.pdf
Description
Full printable version
Size
20.54 MB
Format
Adobe PDF
Checksum (MD5)
3298fa975391c65f54b308c54a1ffb7a
Author(s)
Cerefice, Gary Steven
Advisor(s)
Kenneth R. Czerwinski.
Date Issued
1999
Publisher
Massachusetts Institute of Technology
Abstract
Experimental and analytical studies were performed to examine the environmental behavior of hafnium and its utility as a neutron poison for the disposition of weapons-grade plutonium in Yucca Mountain. The hydrolysis of hafnium was investigated by potentiometric titration in solutions of varying ionic strength to determine the stability constants for the first four monomeric hydrolysis products. The specific ion interaction theory is used to extrapolate these results to infinite dilution. The solubility of hafnium hydroxide and a meta-stable hafnium carbonate solid phase are studied via solubility experiments using ICP-AES. An upper bound for the stability constant of the first carbonate complex is determined. The solubility of hafnium oxide is investigated via solubility experiments using neutron activation analysis, which is also used to investigate the complexation of hafnium by silicates.
(cont.) The potential for a near field criticality incident resulting from the disposition of weapons-grade plutonium at Yucca Mountain is examined using two integrated chemistry and transport models, which are then fed into an MCNP model of the near field at the Yucca Mountain repository. These models are used to predict the effective neutron multiplication factor for the system as the waste package degrades over time. Using the integrated degradation and criticality models, the long term criticality behavior of the proposed WGPu host phase ceramic is examined, as well as the utility of hafnium as a criticality control element for the disposition of weapons-grade plutonium.
Description
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1999.
Includes bibliographical references (leaves 155-161).
Subjects
Nuclear Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Nuclear Engineering
Massachusetts Institute of Technology. Department of Nuclear Science and Engineering
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