3.0 SITE CONSTRUCTION ACTIVITIES
3.1 Construction Mobilization and Training
Major construction items, which will be installed in support of remediation operations, are summarized in this section of the Plan.
Mobilization includes procurement and installation of necessary facilities, equipment, and materials to perform the Remedial Action. Mobilization activities also include the assignment of personnel to the job site; personnel radiation safety and site-specific construction safety training; and regulatory permitting and notifications, as required.
Site specific radiological and general training will be provided for all employees at the commencement of the project. Health and safety training details are provided in the Site Health and Safety Plan (HASP) (Appendix A). Site personnel training certification and its documentation will be maintained by the Site QA Officer with copies submitted to the IOC.
3.2 Site Layout and Temporary Facilities
3.2.1 Site Access and Security
Access to the Site will be restricted by existing fences and locked gates. Site access will be controlled by an existing security gate or by on-site personnel during operational hours. A security guard will be present during all other times. A temporary guard shack will be placed at the existing site entrance, and 24-hour security will be established for the duration of the project. All on-site personnel and subcontractors will be issued identification badges for the duration of the project.
3.2.2 Utilities and Connection Points
Utilities are required for the completion of the remedial action activities. Due to the lack of utility connections within the BOMARC facility, utilities will be provided by onsite equipment. A 40 KW generator will supply electric power to the Laboratory/Office Complex and decontamination facility. A smaller 5KW portable generator will also be located on-site for portable electric power. A service entrance panel and distribution panel will be installed at the Office Trailer and connected to the generator. Service will then be routed to all other trailers and facilities, as needed. The location of the generator is shown in Drawing 799147-C1.
Potable water will be delivered to the site and maintained for the duration of the project. Portable toilets and a dumpster for general office waste will also be provided.
Telephone service will be provided by cellular mobile phones. Two separate lines/phones will be provided for the duration of the field activities. Additionally, portable hand held radios will be utilized for on-site communications.
3.2.3 Support Zone
An office trailer and a mobile laboratory trailer will be set up to support the remediation effort. The location of the support facilities is shown in Drawing 799147-C1. A decontamination (decon)/change trailer will also be provided as discussed later. Additionally, the support zone will consist of Shelter 212 where miscellaneous tools and materials will be stored.
The office trailer will consist of a 40-foot trailer with offices at each end of the trailer. The trailer will be equipped with desks, filing cabinets, work tables, a fax machine, a copy machine, refrigerator, water cooler, and desk top computer with printer for analyzing data collected in the field. Field meetings and training will be conducted within the office trailer.
The mobile laboratory will be sized to accommodate all laboratory equipment. Soil samples will also be archived after analysis and stored in the trailer or a shelter for the duration of the project.
3.2.4 Contamination Reduction Zone
Located adjacent to the Office/Laboratory area is the decontamination facilities, for both personnel and equipment.
The Contamination Reduction Zone includes both the personnel decon/change trailer and equipment Decon Pad. The trailer will be located adjacent to Exclusion Zone and the "clean" support zone. The equipment decon pad will be located directly adjacent to the support zone fencing, but within the Exclusion Zone. The contamination reduction zone located between the Exclusion Zone and the Support Zone will provide a buffer zone for the decontamination of personnel and equipment. This will ensure that, prior to exiting the exclusion work area and entering the "clean" area, all equipment can be decontaminated and verified clean. Potable water and electrical power will be provided.
All personnel and equipment exiting the Exclusion Zone will be surveyed in accordance with the HASP (Appendix A) and the Radiation Protection Plan (Appendix B). All PPE will be removed within this area and bagged for disposal with the excavated soils.
Water from the decon areas will be collected in a sump and used for dust control for the soil excavation and stockpiles areas where the soil is suspected to be above the 8 pCi/g cleanup goal. Prior to use, this water will be filtered through a particulate filter and sampled for radionuclide analysis by the on site laboratory. Water used for dust control will be below 200 pCi/L. Water that is above 200 pCi/L will be held on-site and treated as radioactive material. Water below 20 pCi/L may be disposed to a sanitary sewer.
3.2.5 Exclusion Zone
The Exclusion Zone is the area where all excavation and dismantlement activities are to occur. Entrance into the Exclusion Zone will be through a chain-link gate. The Site Preparation/Layout Plan (Drawing 799147-C1) shows the Exclusion Zone in relation to the Office/Lab area and the Decon area. Entrance into the Exclusion Zone will be restricted to trained personnel only. All persons entering the Exclusion Zone must wear appropriate safety attire and abide by the HASP and related Radiation Work Permits (RWPs). Exiting from the Exclusion Zone will only be through areas designated in the HASP. The Exclusion Zone is delineated either by the chain linked or the silt fence and the appropriate signage.
3.3 Site Preparation
3.3.1 Initial Radiological Survey
Prior to any field activities within the exclusion zone, an initial walk-over radiological survey will be conducted to determine the boundaries of the soil excavation and to confirm the results of the previous investigation.
3.3.2 Land Surveying
A New Jersey Registered Land Surveyor will conduct a topographic survey of the excavation area and vicinity. The surveyor will also perform the following surveys prior to other excavation activities:
· Survey the excavation boundaries as per new walk-over survey,
· Confirm the locations of general site features such as shelter locations, drainage swale, concrete pads, communication bunkers as shown on existing site map,
· Establish bench marks in vicinity of the excavation limits for additional surveying during excavation activities, and
· Locate the sample grid nodes from previous Site Characterization Report.
The land surveyor will provide digital maps in AutoCAD ® Release 14 format and in New Jersey State Planner Coordinate System.
3.3.3 Environmental Control Systems and Monitoring Program
Prior to excavation activities and throughout the remedial action, environmental controls will be implemented to control erosion and sedimentation, manage stormwater runoff, and minimize dust emissions.
3.3.3.1 Erosion and Sedimentation Controls
Prior to performing any intrusive work at the site, erosion and sedimentation controls shall be installed as required. Silt fencing will be utilized to minimize the transport of sediment in storm water runoff. Drawing 799147-C2 indicates the proposed location for silt fence installation. Silt fence shall be installed down-slope of all areas where intrusive work is to occur and down-slope of all soil stockpile areas. Silt fence shall be installed and maintained in active work areas and down-slope of re-vegetated areas until an adequate stand of vegetation is established. The silt fence will be installed by advancing an anchor trench using a Ditch Witch ® trencher.
The silt fence will then be manually installed in the trench.
Erosion control details are shown on Drawing 799147-C2 and 799147-B4 (Appendix F).
3.3.3.2 Storm Water Runoff
Prior to any intrusive work, all storm water runoff will flow off-site via the existing swales and ditches, as presently occurs. In order to prevent surface runoff water entering an active excavation within the Exclusion Zone, soil berms and swales will be installed by mounding the existing site soils at the topographic high point (upslope) of the work area.
Excavating one bucket-width of soil to construct a swale and mounding this soil downslope of the swale to form a berm, will divert uncontaminated water from entering excavations.
Stormwater runoff from areas outside of the excavated areas will not be collected, but shall be diverted from excavation areas, to the extent possible, utilizing drainage ditches and diversion berms.
Stormwater accumulation will be monitored on a daily basis to assure that no stormwater leaves a controlled area. (Analytical method capable of detecting plutonium and americium must be used to verify that the water meets the effluent release criteria of Title 10 CFR Part 20, App. B.) If it is apparent that the stormwater accumulating in a swale or ditch becomes excessive, the water will be pumped to a temporary storage tank located near the decontamination pad for use as dust control in the Exclusion Zone. Also see Section 3.4.3.7, Excavation Storm Water Control.
3.3.3.3 Dust Suppression
Throughout construction, all exposed areas (stockpiles, Shelter 204, excavations) will be watered as needed to minimize dust emissions. Water for dust suppression within areas exceeding the cleanup criteria will be obtained from the storm water runoff, the decon pad, or from the drummed decon water in Shelter 208. Water will be supplemented with an outside source, if necessary.
Water for dust suppression in all other areas will be obtained off-site and stored in a mobile potable water tank located near the proposed decontamination trailer. Dust suppression will occur, as needed, based on visual observation and air monitoring results. A temporary storage tank will be used to store dust suppression water in the Exclusion Zone. A water truck will also be present on-site at all times.
3.3.3.4. Perimeter Radiological Airborne Contaminant Monitoring
Air samplers will be installed at locations around the perimeter of the Site in order to assess the levels of airborne radioactive particulates that have potential for migrating off-site. For details on the location and operation of the air samplers, air monitoring is specified in the Radiation Protection Plan, Appendix B.
Filters will remove particulates from the air pumped through each sampler. The filters will be surveyed in accordance with Radiation Protection Plan, Appendix B. If the radiation levels detected are significant as defined by the SAP, further laboratory analysis will be conducted and work will stop until resolution. If radioisotope activities in the air samples are deemed excessive, then corrective steps will be taken immediately to further reduce dust levels in the work area. The radiological airborne contaminant monitoring will be under the direct supervision of the on-site CHP, and will be field executed by HP technicians with assistance from the Sample Coordinator.
3.3.3.5 Environmentally Sensitive Areas
Botanical surveys of the BOMARC facility have been conducted in the past. During a survey conducted in 1991 two New Jersey listed species of plants; Greene's rush and sickle-leaved golden aster were identified. However during subsequent site visits, no threatened or endangered plants were observed at the remediation site.
As an added precaution, a survey of the excavation and surrounding areas will be conducted to confirm the absence of these plants. If detected, measures will be taken (caution tape, barricades, and personnel training) to minimize disturbance to the plants. The same is true for the borrow fill area.
3.3.4 Decontamination Pad
The vehicle/equipment decontamination pad located within the Exclusion Zone will be constructed using 40-mil liner and 8"x8" wooded posts. Splash walls will be constructed along both sides of the pad using lumber and corrugated sheeting. A power washer will be provided for decontamination, and a sump pit will be installed for the removal of the water from decon pad for use as dust suppression of >8 pCi/g contaminated soils only.
3.3.5 Excavation Soil Stockpile Areas
Excavation stockpile areas will be designated for both contaminated (>8 pCi/g) and clean soils (<8 pCi/g) as determined by the radiological surveying during excavation activities. All excavated soils that are contaminated based on the survey results will be transferred to the contaminated soil stockpile area via a front-end loader. The contaminated stockpiles are located near shelters 102 and 104. The soil stockpiles will be lined on the bottom with 10-mil plastic and on the sides with plastic sheeting and sandbags.
Contaminated stockpiles will be limited to 500 cubic yards. The total contaminated stockpile size will not exceed 1,000 cubic yards during the course of the excavation. The on-site Hazardous Material Broker will coordinate with the transport subcontractor for the removal of the contaminated soils in order to minimize the amount of soils stockpiled on-site. Soil sampling and surveying of the stockpiles will be conducted periodically as required by the disposal facility, the CHP, or the Broker.
The clean stockpile (<8 pCi/g) will be staged on the adjoining row of shelters due to space limitations near the excavation area. The stockpile will be lined similar to the contaminated stockpile. Clean soil will be generated during the excavation due to sloping requirements for access to deeper contaminated soils. In order to remove and transfer clean soils, a "clean work" backhoe will be used to reduce the possibility of cross-contamination.
Clean soil stockpiles will be limited to 500 cubic yards each. As each 500 cubic yard limit is reached, the stockpile will be surveyed and sampled to assess the quality of each stockpile. Soil sampling requirements are documented in the Sampling and Analysis Plan (Appendix C). The soils will be used as backfill at the end of the project after the completion and approval of the Final Status Survey.
The location of the soil stockpiles are depicted Drawing 799147-C1.
3.3.6 Shelter Debris Stockpile Areas
The contaminated shelter debris stockpile area consists of debris generated during the dismantlement of the Shelter 204 and the selective demolition of shelters 202 and 206. As the shelters are dismantled, debris in excess of the release criteria will be segregated and transferred to this stockpile for transport via the intermodal containers to Envirocare. Debris from shelters 202, 204, and 206 with contamination below release limits will be stored on-site at the "clean" debris stockpile as designated by the AF.
3.3.7 Transportation Container Load-out Area
The container load-out area is located at the contaminated soil stockpiles near shelters 102 and 104. The load-out area is where the transportation containers will be loaded with contaminated soils and debris by a front-end loader. The location of the load-out area is depicted on Drawing 799147-C1.
3.4 Site Remediation Operations
This section discusses the various procedures, equipment, and personnel to be used in the dismantlement of Shelter 204 and excavation of the radiologically contaminated soils. The general scope of work includes the removal and off-site disposal of radioactive contaminated soil and building debris.
Excavation of the soils is anticipated to occur within the main excavation area moving from the east to the west. The general location of the excavation is depicted in Drawing 799147-C1 and C2.
During the excavation and demolition process, material will be designated to one of five different categories:
(1) Contaminated soils with activity >8 pCi/g Pu will be segregated for off-site disposal,
(2) Soils with activity <8 pCi/g Pu will be stockpiled on-site for later use as backfill,
(3) Shelter debris which exceeds the release criteria will be segregated for off-site disposal,
(4) Shelter Debris which is below the release criteria will be stockpiled on-site for disposal by others, and
(5) Soils from the launch pit in Shelter 204 will be segregated from other waste for additional sampling. It will be disposed of off-site.
Segregation of the soils and building debris during excavation and dismantlement activities will be based on radiological surveys and on-site sampling results.
3.4.1 Radiological Surveys and Laboratory Analysis
Radiological surveys will be performed during excavation and dismantlement activities to ensure compliance with appropriate regulatory guidelines with respect to release from the site, to determine excavation boundaries, and to document compliance with the cleanup goals. In addition on-site and off-site laboratory analysis will be performed as discussed below:
· The off-site laboratory used for characterization of the waste for disposal purposes must be a Utah certified laboratory.
Five different types of radiological surveys of soils will be performed during the course of this project:
1. A walk-over survey of the perimeter of the excavation will be conducted prior to the start of remedial activities, and during the excavation activities,
2. Shelter 204 surveys prior to and during dismantlement,
3. Routine surveys of roads, load-out areas, decon pads, and soil stockpile areas during remedial activities to ensure that radioactive materials are not being spilled or dispersed around the site as a result of the remedial activities,
4. Release surveys of equipment, materials, tools, and personnel which will be exiting the Exclusion Zone, and
5. Final Status Survey (FSS) of the site following remedial activities prior to backfilling.
3.4.2 Personnel Surveying
Prior to leaving the Exclusion Zone, all personnel will be surveyed for contamination using hand held radiological meters, called "Frisking." Frisking will be conducted within the contamination reduction zone prior to entering the support zone. Details regarding personnel monitoring are presented in the HASP (Appendix A) and the Radiation Protection Plan (Appendix B).
As personnel leave the Exclusion Zone, Tyveks ®, latex gloves, air-purifying respirator cartridges, and other used personal protective equipment (PPE) will be discarded within the CRZ. These items will be disposed in accordance with the Waste Management, Transportation and Disposal Plan (Appendix D).
3.4.3. Shelter 204 Dismantlement
The scope of work for this area includes the complete dismantlement of Shelter 204 and appurtenant structures, and the loading into transportation containers 439 cubic yards of contaminated waste. The structures to be dismantled include Shelter 204, the launch and control pits, and two utility bunkers located in front of the shelter. Safety will be a major concern during dismantlement activities at Shelter 204.
3.4.3.1 Sediment Removal
The sediments in the launch pit will be removed using a mini-excavator. The remaining small amounts of sediments will be removed by hand tools and HEPA vacuum cleaner. Since the sediments in the pit had detectable lead concentrations, this material will be segregated from other soils, and analyzed for lead. If analytical results indicate lead concentrations below 5 mg/l, the soils will be transported with other soils to Envirocare. However, if soils contain elevated lead concentrations, the soils will remain segregated for later transport to Envirocare as hazardous waste.
Likewise, suspect lead based paint covered materials will also be sampled to verify the absence of lead concentrations in excess of the TCLP limit of 5 mg/l. However, the Site Characterization Report indicated that the majority of the paints used in the shelter for fixing contaminants in-place had faded and were no longer present.
3.4.3.2 Decontamination
As a means of controlling radiological contamination, removable contamination will be addressed first. Based on the building survey results, the exposed building interior surfaces will be cleaned using a HEPA vacuum. The waste will be contained in bags and commingled with other material for transportation to Envirocare. Shelter areas with higher radiological contamination or areas that can not be decontaminated will be marked for removal and off-site disposal.
3.4.3.3 Shelter Demolition
Areas of the shelter that could not be surveyed, were not decontaminated, or decontamination efforts failed will be surgically removed from the structure and stockpiled for off-site disposal. Removed sections will be cut into manageable pieces based on transportation or disposal facility requirements. Load bearing beams that require removal will be evaluated on a case by case basis.
The remaining structure will be demolished. The roof will be removed by cutting supporting members using a shear mounted on a trackhoe and allowed to fall to the ground. The roof will then be cut into sections, verified clean, and transferred to an on-site stockpile for disposal by others.
After the removal of the roof, the walls will be demolished in the same manner until the entire structure has been removed and transferred to the appropriate stockpile.
After the removal of the entire structure, the concrete floor, and launch pit will be removed using a hydraulic hammer mounted on a trackhoe. Removed concrete pieces may be surveyed and released based on a release limit of 8 pCi/g. Debris exceeding the release criteria will be segregated and transported off-site for disposal. Surface contamination levels surveys on concrete may be used to release concrete with prior approval of the Certified Health Physicist.
During concrete removal activities within the shelter, a fine water spray may be used to reduce airborne contaminants.
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