Interim Long-Term Surveillance
Plan for the Cheney Disposal
Site
Near Grand Junction, Colorado
April 1998
Office of Scientific and Technical Information
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National Technical Information Service
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U.S. Department of Energy
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Jacobs Engineering Group Inc.
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Preface
The Cheney disposal cell is scheduled to remain open until 2023 or until the cell is filled to its design capacity. The site will operate during the summer months to accept wastes from vicinity properties. Long-term surveillance and monitoring will be conducted on the completed portions of the cell. This preface addresses the unique issues of inspecting and monitoring a partially-operating cell. When the cell is closed, this information will no longer be valid. While the cell is operational, the following information applies:
Acronym | Definition |
BLM | Bureau of Land Management |
DOE | U.S. Department of Energy |
EPA | U.S. Environmental Protection Agency |
LTSP | long-term surveillance plan |
MCL | maximum concentration limit |
NGVD | National Geodetic Vertical Datum |
NRC | U.S. Nuclear Regulatory Commission |
POC | point of compliance |
QA | quality assurance |
RAP | remedial action plan |
TDS | total dissolved solids |
UMTRA | Uranium Mill Tailings Remedial Action |
UMTRCA | Uranium Mill Tailings Radiation Control Act |
This interim long-term surveillance plan (LTSP) describes the U.S. Department of Energy’s (DOE) long-term care program for the Uranium Mill Tailings Remedial Action (UMTRA) Project Cheney disposal site. The site is in Mesa County near Grand Junction, Colorado.
The U.S. Nuclear Regulatory Commission (NRC) developed regulations for the issuance of a general license for the custody and long-term care of UMTRA Project disposal sites in 10 CFR Part 40. The purpose of this general license is to ensure that the UMTRA Project disposal sites are cared for in a manner that protects public health and safety and the environment. Before each disposal site is licensed, the NRC requires the DOE to submit a site-specific LTSP. The DOE prepared this interim LTSP to meet this requirement for the Cheney disposal site. The general license becomes effective when the NRC concurs with the DOE’s determination that remedial action is complete at the Cheney cell and the NRC formally accepts a final LTSP. Attachment 1 contains the concurrence letter from the NRC.
This document describes the long-term surveillance program the DOE will implement to ensure that the Cheney disposal site performs as designed. The program is based on site inspections to identify potential threats to disposal cell integrity. The LTSP is based on the UMTRA Project long-term surveillance program guidance (DOE, 1996a) and meets the requirements of 10 CFR §40.27(b) and 40 CFR §192.03.
The DOE Grand Junction Office (GJO)
will be responsible for all future operation and maintenance of the open
pit area of the cell, temporary storage of future materials, and the transportation
and placement of the materials. The GJO will be responsible for preparing
a Cheney disposal site operations plan and obtaining NRC concurrence.
Remedial action at the
former uranium processing site in Grand Junction, Colorado, and the cleanup
of vicinity properties in and around Grand Junction consisted of excavating
and relocating residual radioactive materials to the Cheney disposal site.The
DOE constructed a disposal cell to control the residual radioactive material
in accordance with 40 CFR Part 192. The site completion report is
being prepared in two phases and contains a detailed description of final
site conditions. Phase I of the completion report reflects activities through
August 1994. The Phase II completion report will document the project to
closure.
The Cheney disposal site was constructed to stabilize waste from a uranium processing site in Grand Junction, Colorado.
The Climax Uranium Company opened a mill in Grand Junction in 1951. It was designed and built for uranium production, with by-product vanadium production. A solvent-extraction circuit was added in 1956. The mill process included ore neutralization, sand/slime separation, and treatments for sand and slime. An acid-leaching and solvent extraction process recovered uranium from the sand. The slimes were salt-roasted, then water-leached to remove vanadium, and finally acid-leached with a solvent-extraction step to extract uranium and the remaining vanadium.
In 1960, the Climax Uranium Company was incorporated into American Metals Climax, Inc., which operated the mill until February 1970. Approximately 4.6 million dry tons of tailings were produced. Climax released approximately 500,000 cubic yards (yd3) (400,000 cubic meters [m3]) of tailings to private individuals and contractors for use as construction fill material from 1951 to 1966.
The mill was dismantled and the tailings pile was stabilized in place from late 1970 to early 1971. Contaminated materials remediated from vicinity properties in the Grand Junction area were stored in the evaporation ponds east of the tailings pile.
In 1989, Phase I of the UMTRA Project remedial action, which included fencing around the processing site, constructing water retention ponds, and constructing the wastewater treatment plant foundation, was completed. Phase II construction began in 1990; it included constructing the disposal cell and assembling the wastewater treatment plant. Tailings relocation to the Cheney disposal cell started in the spring of 1991. Remedial action at the Grand Junction processing site was completed in 1994.
At the Cheney disposal site, the residual radioactive materials were placed in a single disposal cell. Residual radioactive materials from remediation of vicinity properties were also relocated to the Cheney disposal site.
The completion report
documents compliance with the remedial action plan (RAP) and the site as-built
conditions (DOE, 1997). In addition, the DOE will prepare a final audit
report and certification summary and submit it, along with the completion
report, to the NRC for concurrence. Concurrence from the NRC on the completion
report will be included in the permanent site file.
The Cheney disposal site is in Mesa County in southwest Colorado on the western slope of the Rocky Mountains. The site is approximately 18 miles (mi) (29 kilometers [km]) south of the town of Grand Junction, Colorado in Township 3 South, Range 2 East, Sections 11 and 12 (Figure 2.1). The site vicinity is briefly described below. The site environmental impact statement (DOE, 1986) and the RAP (DOE, 1991a) contain detailed descriptions.
The general climatic regime in the vicinity of the Cheney disposal site is semiarid. Summer days with maximum temperatures near 90° Fahrenheit (F) (32° Centigrade [C]) and minimum temperatures near 60° F (16° C) are common. Monthly average temperatures range from 26.6° F (-3.0° C) in January to 78.7° F (26° C) in July. Summer rains occur mainly as scattered intense showers from thunderstorms that develop over the nearby mountains. Winter snows are fairly frequent; however, they are mostly light and the snow melts quickly. Grand Junction’s average annual precipitation is 8.4 inches (21 centimeters [cm]). Snowfall at Grand Junction averages 24 inches (69 cm).
The Cheney site is located on a pediment surface that forms a drainage divide between two small ephemeral washes. The drainage divide slopes gently southwest at approximately 2 percent. The site elevation ranges from about 5190 to 5270 feet (ft) (1580 to 1600 meters [m]) above mean sea level. The two washes merge with Indian Creek, approximately two-thirds of a mile below the site. Indian Creek flows into Kannah Creek 4 to 5 mi (6 to 8 km) below the confluence of the ephemeral washes. Kannah Creek empties in the Gunnison River 2 mi (3 km) beyond its confluence with Indian Creek.
An area of 240 acres (ac) (97 hectares
[ha]) drains toward the Cheney disposal site. Slopes in the watershed average
3 percent. The maximum flow length is approximately 9500 ft (2900 m). Sheetwash
and rill erosion are the primary erosive forces currently active at the
site. Minor gullying occurs in the small ephemeral washes. A small upland
watershed east of the site and a deeply incised surface gully south of
the site are the only significant surface water and geomorphic features.
A drainage swale diverts water from the disposal cell watershed. Water
that falls on top of the cell drains to aprons and to the ground around
the cell.
The United States government currently
owns the Cheney disposal site and most of the surrounding area. The Bureau
of Land Management (BLM) permanently transferred administration of public
land to the DOE in February 1990 for use as the Cheney disposal site. The
BLM administers the adjacent surrounding lands. Attachment 2
gives a legal
description of the disposal site. Plate 1 shows the final site boundary
and identifies ownership of the site and surrounding areas at the time
of licensing.
The Cheney disposal cell covers approximately 60 ac (24 ha) within the 360 ac (146 ha) of land set aside for the site. The completion report contains a detailed description of site conditions, including the results of the site topographic survey (Plate 1).
During final site grading, all areas were contoured to promote drainage away from the disposal cell. A mix of grasses and sagebrush was used to revegetate all disturbed areas of the disposal site not covered by riprap (DOE, 1991b).
At the completion of remedial action,
the DOE documented final disposal site conditions with site maps, as-built
drawings, and ground and aerial photographs.
(Number) survey monuments establish permanent horizontal control based on the Colorado State Plane Coordinate System (Central Zone) and are referenced to the Project Survey Control Points. Plate 1 shows these control points and Table 2.1 gives their location coordinates. The permanent survey monuments (SM-x) are Berntsen RT-1 markers set in concrete, with the monument about 4 inches (10 cm) above ground level. Magnets in the markers permit easier detection if the markers become buried over time. The survey monument identification number is stamped on the top of the metal cap.
(Number) site boundary corners define the final site boundary. Of these, (number) are marked with boundary monuments. The boundary monuments are Berntsen A-1 markers set in concrete. Of these, standard boundary monuments are used at (number) locations. The standard monuments are reinforced concrete that extend to a depth of 6 ft (1.8 m) or to hard rock. The marker extends about 1 inch (2.5 centimeters [cm]) above the ground surface. The remaining (number) monuments have been modified for area conditions and are concrete, placed to a minimum depth of 3 ft (1 m) or 6 inches (15 cm) below rock. In these, the marker extends a minimum of 12 inches (0.3 m) above ground surface. Magnets in the A-1 monuments allow easier detection if they become buried. The boundary monument identification number is stamped on the top of the metal cap.
Two unpolished granite markers with an incised message identify the Cheney disposal site. The message includes a drawing showing the general location of the stabilized disposal cell within the site boundaries, the date of closure, the weight of the tailings, and the amount of radioactivity (in Curies). Site marker SMK-1 near the west site access gate is set in reinforced concrete extending 6 ft (1.8 m) below the ground surface. Site marker SMK-2 is set in reinforced concrete extending to the top of the frost protection barrier.
The DOE posted 18-inch (946-cm) by
24-inch (61-cm) property-use warning signs around the disposal site perimeter
at approximately 200-ft (60-m) intervals. The site entrance sign is at
the south access gate near site marker SMK-1 (location to be confirmed).
The entrance sign displays the DOE 24-hour telephone number for calls concerning
the site. In addition to the entrance sign, (number) perimeter warning
signs are located about 5 ft (1.5 m) inside the site
The disposal cell is constructed partially below grade and rises above the surrounding terrain to a maximum elevation of about 5260 ft (1603 m) above National Geodetic Vertical Datum (NGVD) at the top of the 2.3 percent slope. The disposal cell contains 4,031,402 yd3 (3,082,410 m3) of relocated tailings and other residual radioactive materials, primarily contaminated soils and demolition debris. A cell-closure hole was incorporated into the tailings embankment to allow approximately 500,000 yd3 (382,300 m3) of additional contaminated material from vicinity properties to be placed in the tailings embankment. Clean fill dikes contain the above grade portion of the cell. The dikes are sloped at 20 percent. The top of the cell slopes 2.1 to 2.3 percent.
The top of the disposal cell is capped with a multiple-component cover. A 1.5-ft (0.45-m)-thick transition layer of off-pile materials was placed on top of the contaminated materials. A 2-ft (0.6-m)-thick radon/infiltration barrier was placed over the transition materials. This barrier is constructed of selected on-site materials obtained from the embankment foundation excavation. It is designed to reduce the radon-222 flux from the disposal cell to less than 20 picocuries per square meter per second and minimize water infiltration into the tailings. A 2-ft (0.6 m) frost-protection layer was placed over the radon barrier to prevent the adverse effects of freeze-thaw cycles. A 0.5-ft (0.15-m)-thick, coarse-grained bedding layer on top of the radon/infiltration barrier provides a capillary break, promotes drainage of infiltrating water away from the radon barrier, and prevents damage from the erosion-protection layer. This layer also extends over the clean fill dike sideslopes. The topslopes and sideslopes of the disposal cell are capped with riprap to protect against wind and water erosion and prevent damage to the underlying frost-protection and radon/infiltration barrier layers.
The erosion-protection layer is 1 ft (0.3 m) thick. Maximum grade is 2.3 percent on the topslopes and 20 percent on the sideslopes. These grades, in conjunction with the bedding layer, divert excess surface water runoff from the disposal cell and convey it to adjacent site grades, thereby minimizing the risk of significant erosion. Both the topslope and sideslope covers are designed to minimize the potential for deep percolation of precipitation into the residual radioactive material.
At the toe of the disposal cell a riprap apron and toe ditch carry water away from the cell and provide erosion protection from gullying. A rock-lined interceptor ditch abuts the upslope portion of the disposal cell to divert surface flow away from the cell (DOE, 1997).
The site completion report contains detailed engineering drawings of the disposal cell (DOE, 1997).
The disposal site area is on a broad, moderately sloping surface on the west flank of Grand Mesa, east of the Gunnison River. The surface consists of alluvium, colluvium, and terrace gravels underlain by a thick sequence (greater than 8000 ft [2438 m]) of sedimentary rock. The disposal site is underlain by 5 to 40 ft (1.5 to 131 m) of alluvium. Beneath the alluvium is approximately 700 ft (213 m) of Mancos Shale, which overlies the Dakota Sandstone.
Ground water in the disposal site area occurs transiently in thin paleochannels within the lower portion of the alluvium, in fracture systems in the underlying Mancos Shale; and permanently in the Dakota Sandstone. Detailed field investigations, including geophysical surveys and test pits, identified a large area suitable for the disposal cell that was devoid of paleochannels containing saturation zones. The Dakota Sandstone is defined as the uppermost aquifer beneath the Cheney disposal site.
Alluvial paleochannels exposed by continuous trenches contain saturation zones ranging from less than 1 to more than 6 ft (1.8 m) thick. Paleochannels are separated in some cases by relatively large distances (greater than 500 ft [152 m]). Three separate paleochannel flow systems have been identified in the disposal site vicinity. One system passes within approximately 100 ft [30 m] of the northwest corner of the disposal cell footprint and was relocated outside the footprint. The other two are within approximately 600 ft [183 m] of the southern portion of the footprint.
Ground water in the Mancos Shale is found in discontinuous zones separated both laterally and vertically by large regions of unsaturated rock. Aquifer pumping tests and computer simulations demonstrate that the Mancos Shale yields less than 150 gallons (568 L) per day and is considered "limited use" (DOE, 1991a). Pockets of ground water were found in isolated intervals in the unweathered Mancos Shale at several depths, but principally between 50 and 120 ft (15 and 37 m) and between 275 and 492 ft (84 and 150 m). The ground water occurs in saturated, multiple fracture zones. Core water saturation measurements indicate the Mancos Shale matrix is unsaturated even in zones adjacent to water-filled fractures.
Three monitor wells completed in the Dakota Sandstone encountered confined ground water, with hydraulic pressures greater than 360 ft (110 m) above the Mancos Shale/Dakota Sandstone contact. Ground water in the Dakota Sandstone is confined by unsaturated low-permeability shales and sandstone. Total dissolved solids (TDS) concentrations exceed 10,000 milligrams per liter (mg/L), and thus ground water in the Dakota Sandstone (uppermost aquifer) is considered "limited use" (DOE, 1991a).
Age dating, hydraulic testing, and
chemical analyses show very little, if any, hydraulic connection between
the alluvium, Mancos Shale, and Dakota Sandstone. Comparison of the ages
of paleochannel ground water with the ages of shallow Mancos Shale and
Dakota Sandstone ground water indicates no direct interconnection. Carbon-14
analyses of ground water samples collected from the three units show that
alluvial ground water is relatively young (less than 2000 years), the shallow
Mancos Shale ground water is old (20,000 to 30,000 years), and the Dakota
Sandstone ground water is very old (probably more than 42,000 years).
Background ground water quality in the alluvium is fresh to slightly brackish, with TDS concentrations ranging from 640 to 1690 mg/L. No concentrations of constituents listed in the U.S. Environmental Protection Agency (EPA) ground water protection standards (except selenium) exceed maximum concentration limits (MCL) (DOE, 1991a). Average sulfate and TDS concentrations exceed the EPA National Secondary Drinking Water Standards (40 CFR Part 143) of 250 and 500 mg/L, respectively, by factors of less than 2. Ground water in the alluvium is a mixed cation-sulfate type. Background ground water quality in the
Mancos Shale is brackish, with elevated TDS levels ranging from 870 to 7010 mg/L. Average selenium concentrations slightly exceed the EPA MCL of 0.01 mg/L. Background ground water quality in the Dakota Sandstone is saline, with TDS concentrations exceeding 10,000 mg/L. Ground water in this unit is thus considered "limited use," and the aquifer is neither a current nor a potential source of drinking water. In addition, ground water from this unit contains natural gas, and average concentrations of radium-226 and -228 exceed the EPA MCL of 5 picocuries per liter (pCi/L). Ground water in the Dakota Sandstone at the Cheney disposal site is a sodium-bicarbonate type.
The geochemical environment at the Cheney disposal site is favorable for attenuation of the hazardous constituents present in the Grand Junction tailings pore water. Attenuation data show that alluvial materials are likely to remove concentrations of most hazardous constituents in the tailings pore water to below their regulated concentration limits or laboratory method detection limits. The geochemical condition of the ground water in the Mancos Shale, where it is present below the disposal site, is highly reducing, and it is anticipated that many hazardous constituents (including cadmium, lead, molybdenum, selenium, and uranium) will be removed from the ground water by chemical precipitation. Geochemical modeling shows that these constituents are insoluble in the ground water in the Mancos Shale (DOE, 1991a).
The DOE assessed the performance of the disposal cell in conjunction with the hydrogeologic system. The assessment shows the disposal cell will minimize and control releases of hazardous constituents to ground water and surface water and of radon emanation to the atmosphere, to the extent required to protect human health and the environment (DOE, 1991a). Natural, stable materials were used in constructing the Cheney disposal cell, thereby ensuring long-term performance. The DOE also demonstrated that design features necessary for compliance with the EPA ground water protection standards minimize the need for further disposal cell maintenance.
Dakota aquifer ground water will
not be monitored at the Cheney disposal site. Based on an evaluation of
site characterization data, a program to monitor the uppermost aquifer
to demonstrate disposal cell performance has been determined inappropriate
because ground water in the uppermost aquifer is of limited use, and a
narrative supplemental standard has been applied to the site that does
not include numerical concentration limits or a point of compliance (POC)
(40 CFR §192.21(g)). The basis for the limited use designation is
the fact that ground water in the uppermost aquifer is neither a current
nor a potential source of drinking water because the TDS content exceeds
10,000 mg/L (40 CFR §192.11(e)). Also, the ground water in the uppermost
aquifer at the Cheney disposal site is hydrogeologically isolated from
the tailings material. Defining concentration limits and a POC would not
further protect human health and the environment.
Dynamic water levels will be measured on a continual basis by data loggers and pressure transducers installed in each of these three wells. If sufficient water is observed in these wells, they will be sampled on a semi-annual basis for five years, starting in 1998, and annually after 2003. Sampling will include the following list of indicator analytes: selenium, molybdenum, uranium, vanadium, sulfate, nitrate, PCBs, and TDS. In addition, standard field parameters will be measured. If a monitor well sample exhibits increasing trends, greater than the MCL/risk-based threshold, in one or more parameters during three consecutive sampling rounds, a more rigorous evaluative monitoring program will be conducted. Evaluative monitoring would include quarterly sampling with an expanded list of analytes including arsenic, cadmium, iron, manganese, radium-226 and -228, and gross alpha. Results of evaluative monitoring could invoke further characterization.
Every five years, the need for continued sampling will be re-evaluated. This best management practice monitoring effort should provide an early warning of potential impact to the shallow water in the paleochannels. Should such an indication occur, the DOE will inform the NRC and the state of Colorado, and will perform a detailed re-evaluation of disposal cell performance.
During the summer of 1995, a large
number of volunteer plants were observed growing on the disposal cell.
As a result of the subsequent study, monitoring volunteer plant growth
will be one element of long-term surveillance monitoring at the Cheney
disposal cell. UMTRA Project staff familiar with plant biointrusion on
other UMTRA Project disposal cells visited the site on 19-20 September
1995, to assess plant growth on the cell (TAC, 1995).
Numerous plant were observed growing on the topslope and eastern (2 percent) slope on the cell (Figure 2.2). No plants were observed on the steep sideslopes around the remainder of the cell. All plants observed were growing in soil that had been deposited among the rocks. Areas of the rock cover where the voids were not filled with dirt had no plants. The common plant species observed were summer cypress (Kochia sieversiana), Russian thistle (Solsola iberica), and halogeton (Halogeton glomertus). A few pigweed (Chenopodium sp.) and one shadscale (Atriplex confertifolia) were also observed. The dominant plant species are the same as those observed growing on the Shiprock, New Mexico, disposal cell except for halogeton, which was very rare on the Shiprock cell (DOE, 1992).
The plant growth on the topslope was mapped according to subjectively determined plant density using recent aerial photographs (Figure 2.2). Four plant density categories were identified: negligible, sparse, moderate, and dense. The number of plants within each category was estimated by tallying all plants in 6-ft (2-m)-wide belt transects of varying lengths. Four belt transects were sampled.
Plant growth was observed on approximately
46 ac (19 ha) of the 55-ac (22-ha) topslope. In this area, the few plants
observed were negligible, typically 20 to 50 ft (6 to 15 m) apart. Based
on data from a 600-ft (183-m)-belt in transect C, the estimated density
was 0.0028 plants per square foot (ft2) (0.03 per square meter
[m2]) (Table 2.2). Moderate plant growth covered
an estimated 8.4 ac (3.4 ha). Based on two 100-ft (30-m) transects (transects
A & B), the estimated plant density was 0.82 per 1 ft2 (8.8
per 1 m2). Dense plant growth covered about 1 ac (0.4 ha). Based
on one 100-ft (30-m) transect (transect D), the density was 1.02 plants
per 1 ft2 (11 per 1 m2). Based on these data, the
Table
2.2 Estimated number of plants on the Cheney disposal cell near Grand Junction,
Colorado
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Summer cypress | ||||
Plants per 1 ft2 | 0.0022a | 0.57b | 0.68c | |
Total plants | 4400 | 209000 | 26500 | 239900 |
Russian thistle | ||||
Plants per 1 ft2 | 0.00055a | 0.14b | 0.26c | |
Total plants | 1100 | 51200 | 10100 | 62400 |
Halogeton | ||||
Plants per 1 ft2 | 0 | 0.11b | 0.08c | |
Total plants | 0 | 40200 | 3100 | 43300 |
Total | ||||
Plants per 1 ft2 | 0.0028 | 0.82 | 1.02 | |
Total plants | 5500 | 300400 | 39700 | 345600 |
____________________________________________________________________________
aBased on number of plants
in 1 600 x 6 ft (183 x 2 m) belt transect.
bBased on number of plants
in 2 100 x 6 ft (30 x 2 m) belt transects.
cBased on number of plants
in 1 100 x 6 ft (30 x 2 m) belt transect.
NOTE: Vegetation was measured as sparse (46 ac [19 ha]), moderate (8.4 ac [3.4 ha]), and dense (0.9 ac [0.4 ha]) in September 1995.
55-ac (22-ha) topslope of the Cheney disposal cell contained an estimated 345,600 plants in September 1995 (Table 2.2). Most of the mature plants growing on the topslope were 2 to 4 ft (0.6 to 1.2 m) tall.
Twenty 9-ft2 (0.8-m2)
quadrants were sampled on the 2 percent eastern sideslope and the estimated
number of plants on this 22-ac (9-ha) area was 4,000,000. As with the topslope,
summer cypress was the most common plant. Russian thistle and halogeton
were much more common in this area than on the topslope. Plants in this
area were shorter than on the topslope, typically being 6 to 18 inches
(15 to 46 cm) tall.
Plants were excavated in the sparse and dense plant growth areas to determine rooting patterns. Excavation number one was of a 4.5-ft (1.4-m)-tall summer cypress (Figure 2.2). Soil filled 12 inches (20 cm) of the 14-inch (36-cm) rock layer. A tap root grew through the rock layer ending at the frost protection layer. Lateral roots grew out from the tap root into the rock/soil matrix. Some fine roots were growing into the frost protection layer, but the roots of this plant basically were restricted to the rock/soil matrix portion of the cover.
Excavation number two was in dense vegetation and included a 34-inch (86-cm) -tall Russian thistle, a 32-inch (81-cm) tall summer cypress, and an 18-inch (46-cm)-tall halogeton (Figure 2.2). These plants did not display the branching rooting pattern observed in the summer cypress in the sparse plant density area. Instead, the tap roots went straight down. The halogeton tap root ended in the rock/soil matrix while the tap roots of the Russian thistle and summer cypress grew through the frost protection layer and up to 9 inches (23 cm) into the radon barrier. To verify the apparently shallow halogeton root system, a 17-inch (43-cm)-tall halogeton was excavated; the roots were confined mostly to the 13-inch (33-cm) rock/soil matrix (excavation three).
Based on the limited number of excavations,
it appears that the roots of plants growing in the areas of sparse plant
density may be confined to the rock/soil matrix and the upper part of the
frost-protection layer. Mature summer cypress and Russian thistle growing
in the areas of moderate to dense plant growth likely have grown through
the frost-protection layer and into the radon barrier.
The DOE will inspect the Cheney disposal
site annually. The DOE may schedule more frequent inspections if necessary.
The DOE will notify the NRC of the inspection schedule.
The inspection team will consist of a minimum of two inspectors who are qualified to inspect disposal cell integrity and to make preliminary assessments of modifying processes that could adversely affect the disposal cell.
If problems are observed that require
more investigation, follow-up inspections will be performed and teams will
include one or more technical specialists in appropriate disciplines.
Inspectors will conduct a preinspection briefing before each inspection. The long-term surveillance program guidance document contains information useful in preparing for inspections (DOE, 1996a).
Site inspections will cover the disposal
cell, the surrounding disposal site area, and the immediate off-site areas.
Site inspections must be thorough enough to identify significant changes
or active modifying processes that potentially could adversely impact the
disposal cell. Surveillance will be performed to identify the unanticipated
effects of modifying processes such as gully formation, slope erosion,
changes to the rock cover, ephemeral drainage channel changes, and significant
modifications by humans, animals, or plants.
The disposal cell has a rock cover and vegetation is not planned for the disposal cell. However, remedial action of the areas surrounding the disposal cell included revegetation. The area surrounding the disposal cell will be monitored to determine the success of the revegetation efforts. Inspectors also will inspect this area for evidence of erosion caused by wind, sheetwash, or changes in drainage patterns.
Site inspectors also will monitor damage to or disturbance of permanent site-surveillance features, fencing, the gate, and locks.
From inside the disposal site, inspectors
will visually survey the area approximately 0.25 mi (0.40 km) outside the
disposal site boundary for evidence of land-use changes that indicate increased
human activity such as land development or new roads and paths. Inspectors
will note the condition of and changes to site access roads, surrounding
vegetation, and relevant geomorphic features like gullies or ephemeral
drainage channels. Potential impacts to the site will be noted. Off-site
DOE monitor wells will be inspected until they are properly decommissioned.
In addition to annual inspections, DOE may conduct follow-up inspections due to unusual or annual inspection findings or observations. DOE also may conduct follow-up inspections to investigate and quantify specific problems found during a previous inspection or other DOE-initiated activity, or confirmed reports of vandalism (intrusion or damage), unusual occurrences, or other significant threat to the disposal site. The DOE will monitor the disposal cell area for the occurrence of extreme natural events (e.g., earthquakes, tornadoes, floods) and vandalism to ensure such events are investigated in a timely manner. To facilitate this, the DOE has requested notification from federal, state, and local agencies of discoveries or reports of purposeful intrusion or damage at the disposal site and in the disposal site area. Notification agreements with the Mesa County Sheriff’s Office and the U.S. Geological Survey’s National Earthquake Information Center are included in Attachment 3. The DOE will also monitor the weather for the occurrence of severe storms in the disposal cell vicinity. In addition, the DOE 24-hour telephone number is posted on the site entrance sign so the public can notify the DOE if problems are discovered. If an extreme natural event or vandalism has occurred, the DOE will inspect the cell to assess the damage. The notification, response, and follow-up activities will be documented. This documentation will be included in the annual site report to the NRC and become part of the permanent site file.
The nature of the occurrence and
the amount of firsthand knowledge available will determine the DOE’s response.
If a situation poses a threat to the public, the DOE will notify individuals
who may be affected and the appropriate federal, state, and local agencies,
including the NRC. If necessary, the DOE will schedule a follow-up inspection
to assess potential effects of the unusual occurrence, and will take necessary
response action. Follow-up inspections also will be conducted to determine
whether processes currently active at or near the site threaten site security
or stability and to evaluate the need for custodial maintenance, repair,
or other corrective action. The scope of these follow-up inspections may
be broad and similar in nature to routine site inspections or focus on
specific areas of concern.
The DOE does not plan to conduct routine maintenance at the Cheney site. However, DOE will perform needed custodial maintenance or repair as determined from site inspections. Unscheduled custodial maintenance or repair may include the following:
Repairing or replacing deteriorated or vandalized warning signs, fencing, gates, and locks. Removing deep-rooted plants determined to be a threat to the integrity of the cover. Reseeding areas surrounding the disposal cell.
After the work is completed and before contractors are released, DOE will verify that work was performed according to specification. The annual report to the NRC will document repairs that are performed. Copies of records, reports, and certifications will be included in the permanent site file.
Because ground water monitoring
is not proposed at the Cheney disposal site, the only monitoring will be
visual inspections of surface conditions during routine surveillance and
maintenance. Previously unnoticed seeps or other surface exposures of ground
water observed during routine site surveillance shall be noted and appropriate
water samples shall be collected and analyzed to determine if the water
is contaminated. If the analyses indicate the water is contaminated, the
source of the water and the potential threat to human health and the environment
will be assessed. If appropriate and necessary, the DOE may perform corrective
actions to contain the source of the contaminated water and/or limit exposure
of the land surface to the water. Such corrective actions may include,
but are not limited to 1) constructing a sump or other device to collect
the contaminated ground water before it reaches land surface, and treating
or evaporating the water as necessary; or 2) controlling access to the
contaminated water by covering it with graded, large-diameter rock until
it can reinfiltrate or evaporate. The DOE has determined that the probability
that surface exposure of tailings seepage is nearly zero; therefore, the
necessity for corrective action at the Cheney disposal site is highly improbable.
NRC regulations do not stipulate a time frame for implementing corrective action (except the finding of an exceedance in established ground water concentration limits, which does not apply at this site.) Assessing the extent of a problem and developing a corrective action plan is not considered to be an initiation of the corrective action program.
In addition to the preliminary assessment report, the DOE may, (as appropriate) prepare a progress report on each corrective action while it is under way or under evaluation.
After corrective action is complete, the DOE will certify work and submit a certification statement and supporting documentation to the NRC for review and concurrence. A copy of the certification statement will become part of the permanent site file, as will reports, data, and documentation generated during the corrective action.
Site inspection reports will be submitted to the NRC within 90 days of the annual site inspection. Inspection reports will summarize the results of follow-up inspections and maintenance completed since the previous annual inspection.
If unusual damage or disruption is discovered at the Cheney disposal site during an inspection, a preliminary report assessing the impact must be submitted to the NRC within 60 days. If maintenance, repair, or corrective action is warranted, the DOE will notify the NRC. The NRC will receive a copy of corrective action plans and of each corrective action progress report, or the reports will be attached to the annual report.
The DOE also will provide
copies of inspection reports and other reports generated under the long-term
surveillance program to the state of Colorado as required in the cooperative
agreement.
DOE (U.S. Department of Energy), 1996a. Guidance for Implementing the Long-Term Surveillance Program for UMTRA Project Title I Disposal Sites, DOE/AL-62350-189, Rev. 0, prepared for the U.S. Department of Energy, Environmental Restoration Division, UMTRA Project Team, Albuquerque, New Mexico.
DOE (U.S. Department of Energy), 1996b. Long-Term Surveillance and Maintenance Program, Quality Assurance Program Plan, MAC-2152, Rev. 0, prepared by MACTEC Environmental Restoration Services, for the U.S. Department of Energy, Grand Junction Office, Grand Junction, Colorado.
DOE (U.S. Department of Energy), 1992. Vegetation Growth Patterns on Six Rock-Covered UMTRA Project Disposal Cells, UMTRA-DOE/AL 400677.0000, UMTRA Project Office, Albuquerque Operations Office, Albuquerque, New Mexico.
DOE (Department of Energy), 1991a. Remedial Action Plan and Site Design for Stabilization of the Inactive Uranium Mill Tailings Site at Grand Junction, Colorado, September 1991, DOE/AL-050505.0000, prepared for the U.S. Department of Energy, UMTRA Project Office, Albuquerque Operations Office, Albuquerque, New Mexico, Grand Junction Projects Office, UPDCC File Location No. 13.1.1.
DOE (U.S. Department of Energy, 1991b. Uranium Mill Tailings Remedial Action Project (UMTRAP), Grand Junction, Colorado, GRJ-PH-11, Subcontract Documents, Final Design for Construction, prepared for the U.S. Department of Energy by Morrison-Knudsen Engineers, San Francisco, California.
DOE (Department of Energy), 1986. Final Environmental Impact Statement, Remedial Actions at the Former Climax Uranium Company, Uranium Mill Site, Grand Junction, Mesa County, Colorado, Vol. I, Text, Vol. II, Appendices, DOE/EIS-0126-F, December 1986, UPDCC File Location No. 5.13.1.6., prepared for the U.S. Department of Energy, UMTRA Project Office, Albuquerque Operations Office, Albuquerque, New Mexico.
TAC (Technical Assistance Contractor), 1995. Unpublished field notes, Grand Junction Colorado, UMTRA Project site, 19-20 September 1995, UPDCC File Location No. 5.15.1.1, prepared by the Technical Assistance Contractor, Albuquerque, New Mexico, for the U.S. Department of Energy, Environmental Restoration Division, UMTRA Project Team, Albuquerque, New Mexico.
36 CFR Parts 1220-1238, National Archives and Records, Subchapter B - Records Management, National Archives and Records Administration.
40 CFR Part 143, National Secondary Drinking Water Regulations, U.S. Environmental Protection Agency.
40 CFR Part 192, Health and Environmental Protection Standards for Uranium and Thorium Mill Tailings, U.S. Environmental Protection Agency.
41 CFR Part 101, Federal
Property Management Regulations, General Services Administration.
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