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Title: Imaging and Characterizing the Waste Materials Inside an Underground Storage Tank Using Seismic Normal Modes

Technical Report ·
DOI:https://doi.org/10.2172/757900· OSTI ID:757900

It is necessary to know something about the nature of the wastes in a Hanford underground storage tank (UST) so that the correct hardware can be inserted into a tank for sampling, sluicing, or pumping operations. It is also important to know if a layer of gas exists beneath solid and liquid layers of waste. Given that the tank will have only one liquid observation well (LOW), the authors examined the information that could be obtained from the natural seismic vibrations of a tank as a whole; that is, the normal modes of that tank. As in the case of a bell, the natural vibration, or normal modes, of a tank depend on many things, including the construction of the tank, the kinds of waste materials in the tank, the amount of each material in the tank, and where the energy is placed that excites the vibrations (i.e., where you will ''hit'' the tank). The nature of a normal mode of vibration can be given by its frequency and amplitude. For any given frequency, the amplitude of vibration can be given as a function of position in and around the tank. Since they assumed that one would be ''listening'' to a tank from locations along a LOW, they show their computed amplitudes as a function of position inside and around the tank, and in the case of the physical models they display the observations along various lines inside the tank model. This allowed us to see the complex geometry of each mode of oscillation as a function of increasing frequency.

Research Organization:
USDOE Idaho Operations Office, Idaho Falls, ID; Massachusetts Institute of Technology, Cambridge, MA (US)
Sponsoring Organization:
USDOE Office of Science (SC); USDOE Office of Environmental Management (EM) (US)
DOE Contract Number:
FG07-96ER14705
OSTI ID:
757900
Report Number(s):
DOE/ER/14705-3; TRN: US0004329
Resource Relation:
Other Information: PBD: 14 Sep 1999
Country of Publication:
United States
Language:
English