ML20127H133
| ML20127H133 | |
| Person / Time | |
|---|---|
| Site: | West Valley Demonstration Project |
| Issue date: | 01/26/1984 |
| From: | Richard Perkins, Robertson D, Wogman N Battelle Memorial Institute, PACIFIC NORTHWEST NATION |
| To: | |
| Shared Package | |
| ML20127B821 | List: |
| References | |
| FOIA-84-905 NUDOCS 8505210234 | |
| Download: ML20127H133 (4) | |
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danuary 26, 1984 CHARACTERIZATION OF THE KEROSENE BASE TBP SOLUTION TRANSPORT AT THE WEST VALLEY DISPOSAL SITE D. E. Robertson, N. A. Wogman, and R. W. Perkins (PacificNorthwestLaboratory)
A 30% TBP (tributylphosphate) kerosene base solvent was used at West Valley in the fuel reprocessing operation.
Some of this solvent and associated TBP was disposed of in 500-gallon tanks by burial at the disposal site.
Subsequent corrosion of the tanks has resulted in leakage of this material and its subsequent migration.
The subsequent migration of organic solvents containing complex agents such as TBP and its degradation products is not well understood.
Experience at Hanford indicates that as the organic solvent moves through 'the soil either by saturated or unsaturated flow, the complexing agent TBP is removed and also undergoes d.egradation to form DBP (dibutylphosphate) and EP (monobutylphosphate).
The fate of the associated radionuclides uranium, plutonium, and fission products, is not well known.
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The purpose of this proposed work is first to identify the migration of -
the kerosene base solvent, the associated TBP and its degradation products, along with associated radioactivity, and second to characterize the mechanisms of saturated and unsaturated flow which result in the transport of these materials.
It is suggested that the work be carried out in two phases--Phase I will involve a survey of the extent of migration, while Phase II will involve a characterization of the actual mechanisms involved in the transport process. Phase I could be carried out over a period of 4-6 months, while Phase II would require an additional one year for its completion.
Phase I.
Survey of the Extent of Migration of the Kerosene Base Solvent and Associated TBP and Radionuclides 1.
Task 1 - Determination of the Extent of Migration of the Kerosene Base Material Using a Gas Chromatographic Sniffer Technique In this task soil gases will be sampled at increasing radial 8505210234 850103 NNIO
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',6-distances from known underground source locations.
This will allow a quick analysis of the extent of migration of the kerosene base materials and therefore provide a basis for determining the possible movement of the TBP and associated radionuclides.
We would plan to carry this work out.on site by taking soil gas samples at distances from soil depths to one meter and measuring the hydrocarbon materials characteristics of the kerosene base solvent.
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Task 2 - Analysis of Liquid Kerosene Base Materials Which Have Moved from the Source The objective of this work will be to determine the relationship of the kerosene base liquids which have migrated to distances of several meters from their source locations to the source material.
It is important to establish how efficiently liquid migration of the kerosene base material carries TBP, its associated degradation products, and radionuclides.
A comparison of these dissolved constituents with those present in the source material will allow the approximate retardation f
factors for the major substances to be determined.
3.
Task 3 - Association of Radionuclides with the Complexants t
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The major radionuclides in the kerosene base TBP solution include uranium and plutonium isotopes,106 u, 60 o,125Sb,137 s, 90 r, and R
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probably other long-lived constituents. To understand the potential for j
long range migration of radionuclides, it is important to determine if they are present as complexants of TBP, DBP, or MBP.
Several liquid samples from monitoring locations will be collected and analyzed to determine if the radionuclides are present as complexes.
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Task 4 - Determination of the Ratios of TBP, DBP, and MBP in Soil Core Samples Through Which the Kerosene Base Material Has Moved Limited experience at Hanford suggests that TBP is rather efficiently removed during migration through soils and that its degradation to form DBP and MBP occurs at significant rates.
This task will involve the analysis of core samples which have already been collected and through which the kerosene base TBP solution has passed, with the objective of
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detemining both hold-up of TBP and its degradation products, and the apparent rate of TBP degradation.
Phase II. Migration Mechanisms for the Saturated and Unsaturated Flow of Kerosene Base TBP Solutions The objective of this portion of the work will be to determine the actual. mechanisms - by 'which the kerosene base solvent and its associated solutes are transported through soil, both by saturated and unsaturated flow.-
i 1.
Task 1 - Organic Solvent, Transport of TBP, DBP, and EP Because of - the very low surface tension of kerosene base solvents relative to water, it may be - that this solvent will migrate at a relatively high rate above the water saturated zone in the soil matrix.
The actual rate of transport by saturated flow will be evaluated for the weathered zone areas that allow more rapid transport.
By selecting monitoring sites downstream hydrologically from the sources, it should be - possible to establish transport rates, retardation factors, and t
degradation rates'for TBP and its degradation products.
It should also be possible to establish the effectiveness of radionuclide transport by these substances during liquid flow of the solvent.
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Task 2 - Distribution of Solute Material Between the. Organic and Aqueous Phases As the organic solvent moves through the soil system in contact with underlying water, there will be an exchange of the complexants (TBP, DBP, and MBP) between these two solutions.
There will also be an exchange of the associated radionuclides.
The rate of exchange will affect the ability of the organic solvent to transport the complexants and associated radionuclides at a higher rate than that which would result by aqueous flow.
To establish a basis for evaluating the potential acceleration of radionuclide transport, we will collect samples downstream hydrologically of both the organic solvent and associated aqueous layers to establish the exchange rate of the complexants and radionuclides between these phases and also determine i
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t if the radionuclides are actually associated with complexants in both phases' as material moves away from the sources.
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Task 3' - Unsaturated Flow of-the Organic Solvents and Associated Solutes Because of the very low surface tension of the organic solvent it can be expected to move by unsaturated flow and by vapor flow at a much higher rate than moisture would move.
At Hanford, this seems to be the mechanism by which the kerosene base material moved away from the I
dissolved TBP and the TBP degradation products.
We can expect that the organic solvent would move by unsaturated flow toward the surface and j
. eventually vaporize and be lost to the atmosphere.
The important question is, how well would the associated TBP, its degradation products, and associated radionuclides move?
To determine this, we would collect soil cores within the saturatad organic solvent layer and upward to the surface and analyze these for the organic solvent, the complexants, and the radionuclides.
This would allow us to establish whether the solutes are effectively transported by unsaturated flow to
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the ground surface.
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Estimated Manpower Requirements We estimate that to carry out all of the tasks in Phase I would require approximately six months with a total of a one man-year effort.
Phase II would require approximately one additional year with a total effort. of i
f approximately 2.5 man-years.
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