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Title: Infiltration control for low-level radioactive solid waste disposal areas: an assessment

Abstract

The primary mode of radionuclide transport from shallow land-disposal sites for low-level wastes can be traced to infiltration of precipitation. This report examines the factors that affect surface water entry and movement in the ground and assesses available infiltration-control technology for solid-waste-disposal sites in the humid eastern portion of the United States. A survey of the literature suggests that a variety of flexible and rigid liner systems are available as barriers for the stored waste and would be effective in preventing water infiltration. Installation of near-surface seals of bentonite clay admixed with dispersive chemicals seem to offer the required durability and low permeability at a reasonable cost. The infiltration rate in a bentonite-sealed area may be further retarded by the application of dispersive chemicals that can be easily admixed with the surface soil. Because the effectiveness of a dispersive chemical for infiltration reduction is influenced by the physico-chemical properties of the soil, appropriate laboratory tests should be conducted prior to field application.

Authors:
Publication Date:
Research Org.:
Oak Ridge National Lab., TN (USA)
OSTI Identifier:
6818804
Alternate Identifier(s):
OSTI ID: 6818804
Report Number(s):
ORNL/TM-6473
TRN: 80-018555
DOE Contract Number:
W-7405-ENG-26
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; GROUND WATER; RADIONUCLIDE MIGRATION; PERMEABILITY; CONTROL; RADIOACTIVE WASTE DISPOSAL; LOW-LEVEL RADIOACTIVE WASTES; UNDERGROUND DISPOSAL; BENTONITE; CLAYS; SOILS; SOLID WASTES; SURFACE WATERS; ENVIRONMENTAL TRANSPORT; HYDROGEN COMPOUNDS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MANAGEMENT; MASS TRANSFER; MATERIALS; MINERALS; OXYGEN COMPOUNDS; RADIOACTIVE MATERIALS; RADIOACTIVE WASTES; WASTE DISPOSAL; WASTE MANAGEMENT; WASTES; WATER 052002* -- Nuclear Fuels-- Waste Disposal & Storage; 520301 -- Environment, Aquatic-- Radioactive Materials Monitoring & Transport-- Water-- (1987); 053000 -- Nuclear Fuels-- Environmental Aspects

Citation Formats

Arora, H.S. Infiltration control for low-level radioactive solid waste disposal areas: an assessment. United States: N. p., 1980. Web. doi:10.2172/6818804.
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Arora, H.S. Infiltration control for low-level radioactive solid waste disposal areas: an assessment. United States. doi:10.2172/6818804.
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Arora, H.S. Sat . "Infiltration control for low-level radioactive solid waste disposal areas: an assessment". United States. doi:10.2172/6818804. https://www.osti.gov/servlets/purl/6818804.
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@article{osti_6818804,
title = {Infiltration control for low-level radioactive solid waste disposal areas: an assessment},
author = {Arora, H.S.},
abstractNote = {The primary mode of radionuclide transport from shallow land-disposal sites for low-level wastes can be traced to infiltration of precipitation. This report examines the factors that affect surface water entry and movement in the ground and assesses available infiltration-control technology for solid-waste-disposal sites in the humid eastern portion of the United States. A survey of the literature suggests that a variety of flexible and rigid liner systems are available as barriers for the stored waste and would be effective in preventing water infiltration. Installation of near-surface seals of bentonite clay admixed with dispersive chemicals seem to offer the required durability and low permeability at a reasonable cost. The infiltration rate in a bentonite-sealed area may be further retarded by the application of dispersive chemicals that can be easily admixed with the surface soil. Because the effectiveness of a dispersive chemical for infiltration reduction is influenced by the physico-chemical properties of the soil, appropriate laboratory tests should be conducted prior to field application.},
doi = {10.2172/6818804},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Nov 01 00:00:00 EST 1980},
month = {Sat Nov 01 00:00:00 EST 1980}
}
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Technical Report:
View Technical Report (1.19 MB)
DOI:  10.2172/6818804
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  • ; ;
    Water infiltration to buried waste is the prime problem of concern in designing waste disposal units for the humid areas. Conventional compacted clay layers (resistance layer barriers) have been subject to failure by subsidence and by permeability increases bought about by plant roots. A clay barrier with a rock cover without plants is being investigated. Also a combination of a resistive layer overlying a conductive layer is being investigated. Laboratory studies indicate that this approach can be very effective and field evaluations are underway. However, it must be noted that subsidence will negate the effectiveness of any buried layer barriers.more » A surface barrier (bioengineering management) has been evaluated in the field and found to be very effective in preventing water entry into waste disposal units. This surface barrier is easily repairable if damaged by subsidence and could be the system of choice under active subsidence conditions. 5 refs., 20 figs.« less

  • ; ;
    Three kinds of waste disposal unit covers a barriers to water infiltration are being investigated. They are: (1) resistive layer barrier, (2) conductive layer barrier, and (3) bioengineering management. The resistive layer barrier consists of compacted earthen material (e.g. clay). The conductive layer barrier consists of a conductive layer in conjunction with a capillary break. As long as unsaturated flow conditions are maintained the conductive layer will wick water around the capillary break. Below grade layered covers such as (1) and (2) will fail if there is appreciable subsidence of the cover. Remedial action for this kind of failure willmore » be difficult. A surface cover, called bioengineering management, is meant to overcome this problem. The bioengineering management surface barrier is easily repairable if damaged by subsidence; therefore, it could be the system of choice under active subsidence conditions. The bioengineering management procedure also has been shown to be effective in dewatering saturated trenches and could be used for remedial action efforts. After cessation of subsidence, that procedure could be replaced by a resistive layer barrier, or perhaps even better, a resistive layer barrier/conductive layer barrier system. This latter system would then give long-term effective protection against water entry to waste and without institutional care. These various concepts are being assessed in six large (70ft {times} 45ft {times} 10ft each) lysimeters at Beltsville, Maryland. 6 refs., 20 figs.,« less

  • From a survey of DOE sites, facilities, and practices for the disposal/storage of low-level radioactive solid waste, the following can be summarized: (1) No health hazard has been reported. (2) Some burial grounds are releasing small quantities of radionuclides to the immediate environment. These releases are well within release limits at all sites with the exception of on-site concentrations at ORNL. At ORNL, concentrations in the Clinch River are less than 1% of the release limits. (3) Many practices have been instituted in the last few years which have improved disposal/storage operations considerably. The most notable are: (a) improved recordmore » keeping and a centralized computer data file, (b) improved burial site surface maintenance and drainage control, (c) initiation of the use of waste compactors and current plans for their use at most burial sites, (d) initiation of studies at major sites for evaluation of the long-term impact of buried waste, (e) improvement of modeling/monitoring programs at all major sites, (f) initiation of studies to provide engineering methods of reducing burial ground discharges at ORNL, and (g) initiation of the shallow land burial technologoy program.Overall, the low-level waste is being disposed of and stored in a safe and orderly manner. Recent and planned improvements will provide increased environmental protection. The only unsatisfactory area involves record keeping. Records of waste buried years ago are either poor or nonexistent. This makes it very difficult to evaluate the total impact of some 30 years of disposal operations. While some of this important history is lost forever, projects now under way should be able to reconstruct most of it.« less

  • This report provides an analysis of infiltration and percolation at a hypothetical low-level waste (LLW) disposal facility was carried out. The analysis was intended to illustrate general issues of concern in assessing the performance of LLW disposal facilities. Among the processes considered in the analysis were precipitation, runoff, information, evaporation, transpiration, and redistribution. The hypothetical facility was located in a humid environment characterized by frequent and often intense precipitation events. The facility consisted of a series of concrete vaults topped by a multilayer cover. Cover features included a sloping soil surface to promote runoff, plant growth to minimize erosion andmore » promote transportation, a sloping clay layer, and a sloping capillary barrier. The analysis within the root zone was carried out using a one-dimensional, transient simulation of water flow. Below the root zone, the analysis was primarily two-dimensional and steady-state.« less

  • ; ;
    In the humid eastern part of the United States, trench covers have, in general, failed to prevent some of the incident precipitation from percolating downward to buried wastes. It is the purpose of the present work to investigate and demonstrate a procedure or technique that will control water infiltration to buried wastes regardless of above or below ground disposal. Results to date show the proposed procedure to be very promising and are applicable to shallow land burial as well as above ground disposal (e.g., Tumulus). In essence, the technique combines engineered or positive control of run-off, along with a vegetativemore » cover, and is named ''bioengineering management''. To investigate control of infiltration, lysimeters are being used to make complete water balance measurements. The studies have been underway at the Maxey Flats, Kentucky, low-level waste disposal facility for the past three seasonal years. When the original Maxey Flats site closure procedure is followed, it is necessary to pump large amounts of water out of the lysimeters to prevent the water table from rising closer than 2 meters from the surface. Using the bioengineering management procedure, no pumping is required. As a result of the encouraging initial findings in the rather small-scale lysimeters at Maxey Flats, a large-scale facility for demonstration of the bioengineering management technique has been constructed at Beltsville, Maryland. This facility is now operational with the demonstration and data collection underway. 6 refs., 15 figs.« less