10.2.9-_ECC_-_As-Left_Report.pdf

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ENG FORM 4025, MAR 95 (ER 415-1-10) EDITION OF SEP 93 IS OBSOLETE. (Proponent: CEMP-CE)

11/30/2015 01700-4

01700

W912DY-10-D-0013 CF01

Southern New Jersey REO 130 North Broadway Gloucester City, NJ 08030

Environmental Chemical Corporation 110 Fieldcrest Avenue Edison, NJ 08837

FUSRAP Radioactive Soil Removal Deepwater, NJ

X

X

Please find attached As-Left report for DuPont Chambers FUSRAP project. There is no specification requirements for this report.

However, As agreed during Termination Conference meeting on June 4, 2015. ECC has prepared this As-Left report to provide USACE of as left condition of the project. So this report is submitted for information only.

4 As-Left Report CLOSEOUT SUBMTL 3 1.3 A N

SHEET 1 OF 1

Digitally signed by Rinku Shah DN: cn=Rinku Shah, o=ECC, ou, email=RShah@ecc.net, c=US Date: 2015.11.29 18:02:53 -05'00'

AS LEFT REPORT

REMEDIATION SERVICES

FORMERLY UTILIZED SITES REMEDIAL

ACTION PROGRAM (FUSRAP)

AT THE

DUPONT CHAMBERS WORK SITE

DEEPWATER, NEW JERSEY

Prepared for

United States Army Corps of Engineers Philadelphia District

Contract Number

W912DY-10-D-0013

Task Order CF01

November 2015

Environmental Chemical Corporation 110 Fieldcrest Avenue, Suite 31

Edison, NJ 08837 i

AS LEFT REPORT

REMEDIATION SERVICES

FORMERLY UTILIZED SITES REMEDIAL ACTION PROGRAM

DUPONT CHAMBERS WORKS SITE

DEEPWATER, NEW JERSEY

November 2015

I hereby certify that the enclosed As Left Report, shown and marked in this submittal, is that proposed to be incorporated with Contract Number W912DY-10-D-0013, Task Order CF01, “Former DuPont Chambers Works Site, Deepwater, New Jersey”. This report is in compliance with contract drawings and specifications, and is submitted for Government approval.

Reviewed by:

ECC Project Manager Date

ECC Quality Control System Manager Date

Digitally signed by Rinku Shah DN: cn=Rinku Shah, o=ECC, ou, email=RShah@ecc.net, c=US Date: 2015.11.25 13:37:37 -05'00'

Digitally signed by David Garber DN: cn=David Garber, o=ECC, ou, email=dgarber@ecc.net, c=US Date: 2015.11.25 16:45:00 -05'00' ii

Contents Overview

Site Layout and Logistics

Remedial Goal

Soil

Surfaces

AOC 6

SU5

SU5 Remediation and As left Assessment

SU5 Remaining activities

SU4

AOC 1

SU3 Remediation and As left Assessment

SU3A Remediation and As Left Status

SU3 and SU3A Remaining Activities

SU3, Subsection 3.1

SU3, Subsection 3.2

SU3, Subsection 3.3 & 3.4

SU3, Subsection 3.5 & 3.6

SU3, Subsection 3.7

SU3A, Subsection 3.A

SU3A, Subsection 3.B

SU3A, Subsection 3.C

SU3A, Subsection 3.D

AOC 2

AOC 2 Remediation and As Left Status

AOC 2 Remaining Activities

Waste Transfer Facility (WTF) iii

Waste Transfer Facility Construction and As Left Status

Haul Roads

Contaminated Water Treatment Plant (CWTP)

Trailers and Storage Units

Yardage Summary

Table of Figures

Figure 1. DuPont Chambers Works Site, Deepwater, NJ Figure 2. USACE Operable Units and Areas of Concern, DCW FUSRAP Figure 3. AOC 6, SU5 As left Status Figure 4. AOC 1, SU3 Primary Cut Lines with Original Building Footprint Superimposed Figure 5. SU3 and SU3A As Left Status Figure 6. SU3, Subsection 3.1 and 3.2 Detail Figure 7. SU3, Subsection 3.3 & 3.4 Detail Figure 8. SU3, Subsections 3.5, 3.6, and 3.7 Detail Figure 9. SU3A, Subsection 3.A and 3.B detail Figure 10. SU3A, Subsection 3.C Detail Figure 11. SU3A, Subsection 3.D Detail Figure 12. AOC 2, As Left Status Figure 13. AOC 2, Final Perimeter Gamma Walkover Survey Figure 14. Waste Transfer Facility Figure 15. Rail Loadout Area Figure 16. As Left Haul Road Survey Figure 17. Detail of As Found Elevated Area along Haul Route Figure 18. Office Trailer Locations Figure 19. DuPont Chambers Works Site Remediation Yardage Summary, November 24, 2015

Exhibits

Exhibit 1. Historical Information Related to Non FUSRAP Material Burials

Overview

In the spring of 2015 ECC was informed by the USACE that its contract was being terminated due to funding and incorrect contract type issues. At this point in the project ECCwas conducting active remedial activities at Area of Concern (AOC) 6 and AOC 1. AOC 2, the projected deep excavation through significant quantities of oil distillates, had been ringed in sheet pile during the winter to support dewatering activities that were projected to occur in the summer/fall of 2015. ECC, with the USACE, worked through several funding/work scenarios to finalize high priority work elements and complete the temporary stabilization of all areas and facilities prior to project shutdown. This report has been developed to document the last and best information available during this final stage of the project. The report provides drawings accompanied by narrative addressing each AOC and survey unit, each of the primary support facilities, and provides an assessment (sometime speculative in nature) of what work remains to be completed.

Site Layout and Logistics

The remediation site is split into twomain areas, AOC 6 and AOC 1&2. Both sites reside within the DuPont ChambersWorks chemical plant. The facility is heavily secured and strict training and access requirements are enforced. Once acclimated to these requirements, vendor/support contractor access for the provision of tools, equipment, material, specialty support can be coordinatedwith sufficient lead time and planning.

Non badged personnel must be escorted and there are certain logging and paperwork requirements that must be followed for deliveries and support. An overall depiction of the site, with AOC 6 and AOC 1&2 is provided in Figures 1 and 2.

Remedial Goal

Soil

The Record of Decision Document (ROD) provides a remedial goal (RG) of 65 pCi/g total uranium. The uranium processed at the site is in its natural state (48.9% U 238, 48.9% U 234, 2.25% U 235 on an activity basis). Also, according to the ROD, any residual levels of Th 230 or Ra 226 that existed via incomplete initial separation during the original processing or what has ingrown over the past 50 to 60 years would be essential removed to levels indistinguishable from background upon achievement of the RG for uranium.

Surfaces

There was, and remains, the likelihood that subsurface utilities (and potentially other surfaces) will be found within the open excavations. However, the ROD did not provide a surface release criteria for surfaces that might be encountered, thus the project adopted the ANSI N13.12 screening values with a dose limitation of 1.0 mrem/y Total Effective Dose (TED) to an average member of the public. From Table 1, ANSI 13.12 2013, Total Uranium is a Group 2 Radionuclide, with an associated release limit of 6000 dpm/100 cm2. The maximum contribution from Th 230 plus Radium 226 (both Group 1 radionuclides with a release limit of 600 dpm/100 cm2) was estimated at 5% of the residual uranium level. Thus, a derived mixture release level was developed assuming 95% uranium and 5% Th/Ra radionuclide mixture ratio. The resulting surface release limit, assuming a 10% removable fraction, was calculated to be:

4100 dpm/100 cm2 total alpha, 410 dpm/100 cm2 removable alpha

Figure 1. DuPont Chambers Works Site, Deepwater, NJ

Additionally, recognizing that uranium has essentially an equal number of beta and alpha emissions, the project was able to assess alpha surface contamination using beta measurements (increased by a factor of 1.05 to account for the contribution from Th 230 or Ra 226). Beta measurements have better measurement characteristics and thus are more sensitive and faster than alpha measurements. Lastly, these release values were adopted and used for the release of equipment and materials used on the site.

The derivation of the volumetric and surface release criterion is provide in the Final Status Survey Plan (USACE 2013) developed and approved for use on the project.

Figure 2. USACE Operable Units and Areas of Concern, DCW FUSRAP

AOC 6

AOC 6 contained two areas to be remediated. These were designated as SU5 and SU4.

SU5

Note: Within this narrative addressing SU5 the waste management processes developed and employed on the project as a whole is also described. While this process was used at all excavations, the narrative is placed only under SU5 for the sake of brevity. All waste on site was classified as UQSM except for SU5, which was classified as mixed waste RCRA.

SU5 (located in the NE portion of the AOC) was a former burial site that was believed to contain uranium process materials transported there from AOC 1&2. Carbon 14 drums were believed to have been buried south west of SU5 (see Exhibit 1). Collection of C 14 samples from the nearest excavation face running in this direction was planned for however work in this area was halted due to the discovery of an intact stainless steel drumwhich resulted in a discontinuation of remedial activities in this area prior to sampling.

In September, 2014 remediation activities began in AOC 6, within SU5 (the NE excavation area) and within SU4 (the SE excavation area) by test pitting at several locations down to the primary cut line design depths.

The primary cut lines were provided to ECC by the USACE based upon remedial investigation data and was believed to contain the minimum volume of material that would require excavation to meet the remedial goal of 65 pCi/g total uranium. Test pit samples were collected at intervals below ground surface (bgs);

e.g., 0 – 2 and 2 – 4, feet bgs samples were collected and composited into a single composite sample for the area depth which was sent for radiological and chemical analysis. This information was used to determine waste classification and assess initial health and safety protocols to be implemented.

The results of the initial test pit sampling demonstrated that SU5 was a mixed waste RCRA area due to the high concentrations of lead discovered. In a related development applicable to all excavations, ECC and the USACE agreed (following a written excavation control plan) that specific excavation areas would retain the initially derived waste profile designation unless:

A visual determination was made that different material was encountered (necessitating waste isolation and confirmatory sampling).

On site radiological analysis indicated that LLRW was encountered (necessitating confirmatory sampling).

On site IH monitoring indicated that addition or different chemicals were encountered (necessitating confirmatory sampling).

Thus, once the primary cut line excavation were complete, ECC would request approval to continue remediation of uranium bearing materials found > the RG. This “secondary excavation” was driving by the results of walkover gamma sampling in combination with on site soil analysis using a high purity germanium (HPGe) detector. ECC used a combination of NaI detectors (Ludlum 44 10 2x2 inch and Rexon NaI 3 ½ by 3 inch) to guide excavation. The Rexon detectors proved well suited in that they were ruggedized for field use, similar to the 44 10, but exhibited a much lower ambient gamma background.

SU5 Remediation and As left Assessment

SU5 was excavated during the fall/winter to a depth of approximately 9 to 13 feet. Water infiltration required continual attention and management. Drum carcasses and debris, mixed with dyes, chemicals, significant quantities of tetraethyl lead (TEL) were found throughout the excavation. An intact drum of unknown content was found at approximately the 5” depth in the SW quadrant of the excavation. At this point, excavation in the area was effective halted, the intact drum was transported following an approved execution plan to a “sampling tent” where it was subsequently opened and sampled. Following this, the remaining stockpiled material from SU5 was loaded out and shipped off site. The excavation was isolated from storm water run off, the sides of the excavation were lined with poly sheeting, and the area was barricaded off and posted as a radiological contamination area and an execution zone. All equipment and material were decontaminated and free released off site and/or controlled as residually contaminated material (e.g., pump hoses).

SU5 Remaining activities

The primary cut lines (found as Figure 3) were determined as concentric oblong areas of 7, 9, and 11 feet excavation bgs. SU5 remained flooded throughout much of the project and remains so. Due to these water issues the deepest part of the excavation (~11 to 13’ bgs) was never GPS gammawalkover surveyed.

However, the excavation control technician covering the work at the time believed that the RG had been reached in this area.

A large hot spot was encountered at about the 4 to 5 foot depth in the SW quadrant of the area. The extent of additional excavation in this area is estimated to be 3’, for a total volume of 212 CY. This is a speculative estimate based on the depth of material found around this hot spot.

Figure 3. AOC 6, SU5 As left Status

This same (SW Quadrant) hot spot is speculated to run as a lens, several feet deep, to the SW of SU5. This lens, and the overburden and lay back required to get to it, results in a speculated volume of 2054 CY.

Note also, this area contains “purple” gradient material, meaning that this will need to be homogenized with less radioactive material to ensure it can be shipped as UQSM.

The remaining contaminated area in the center of the excavation (at the 9’ bgs elevation) is speculated to contain 370 CY. This area was cleaning up fairly well when remediation activities were halted in this area and the excavation control technician believed he was close hitting the RG.

The southern portion of SU5 was always covered by the load out pile and thus no data is available.

However, as a conservative estimate, the volume of material requiring removal is speculated to be approximately 1605 CY.

SU4

SU4 was remediated to levels meeting the RG as demonstrated by the Final Status Survey Report for the site. The area was backfilled and graded. Erosion controls were put in place. The fencing around this area has been removed and the paved road running though it was put back into its original condition. No additional remedial work is required in this area.

AOC 1

AOC 1 contains SU3 and SU3a. SU3 is a large area which contains foundation debris associated the original processing facility located on the site, see Figure 4.

Figure 4. AOC 1, SU3 Primary Cut Lines with Original Building Footprint Superimposed

SU3 Remediation and As left Assessment

SU3 runs up against the site fence located to the NE of the area, just across the fence a long wooden trough runs parallel to the railway track approximately 10’ beyond. SU3 was test pit sampled down to 2 or 4 feet (depending on the primary cut depth) and determined to be non RCRA contaminated. Uranium levels were found in layers well above UQSM levels in thin layers and pockets. The elevated material was homogenized with low activity material and once aggregated it was sampled and found to be < LLRW levels (i.e., UQSM). SU3 contained significant quantities of intact and broken concrete; much of the uranium contamination was found interspaced with this concrete and it appeared that subgrade process lines, containing more concentrated materials, were being exposed during excavation. A partially intact underground storage tank was found in the NW section of SU3 (in Figure 4 the tank was located about where the “A” in “AOC 1” is located. This tank contained heavily stained soil and a dark petroleum product. The soil at this area was tested and confirmed to be non RCRA. The area expanded during remediation; the two separate areas grew together and each expanded out ward. A contaminated soil berm, running east to west, was constructed through the center of the unit to assist with water management activities. The area was excavated to a depth of approximate 7 to 8 feet bgs. At this depth a clay/sandy soil layer was reached and the unit appeared to be cleaning up. A live water line was found in the SE portion of the survey unit, contamination remains around this pipe.

During shutdown operations the excavation sides were poly lined. The area was barricaded off and posted as a radiological contamination and chemical exclusion zone. The as left condition is depicted in Figure 5.

Figure 5. SU3 and SU3A As Left Status

SU3A Remediation and As Left Status

SU3A is located SWof SU3. Thewest side of SU3A borders the Central Drainage ditch. This area contained higher level uranium which was homogenized with lower activity material and when aggregated was found to be below LLRW levels (i.e., UQSM). During the initial excavation of this area darkly stained, very odoriferous, material was encountered. This material was sampled and found to be non RCRA.

Excavation proceeded rapidly in this area and most of the southern half was cleaned. A large concrete pad was found to occupy the NE section of the survey unit. Excavation was inhibited by the location of a monitoring well directly centered in contaminated portion of the unit. This well was grouted in place and readied for removal in the May/June 2015 timeframe; however excavation of this area was discontinued prior to actual well removal.

During shutdown operations a jersey barrier wall was placed between SU3A and the central drainage ditch. This wall was lined with clean gravel/soil. The barrier was then poly lined. The excavation wall were also poly lined. The whole area was barricaded off and posted as a radiological contamination area and a chemical exclusion zone.

SU3 and SU3A Remaining Activities

The as left status of SU3 and SU3A is depicted in Figure 5. This figure provides the as left or near to as left gamma walkover data, the primary cut line boundaries, the exclusion zone boundaries, and the projected areas were more excavation may be required. For discussion purposes, SU3 and SU3A have been broken into several smaller subsections; Section 3.1, 3.2, 3.3, 3.4., 3.5, 3.6 and 3.7 are associated with the anticipated future remediation of SU3. Sections 3.A, 3.B, 3.C, 3.D, cover SU3A, two smaller areas to the west of SU3A, and the area between SU3A and SU3.

SU3, Subsection 3.1

This is a contaminated lens of material, perhaps a few feet deep, located about 2 – 3’ bgs, running NW out of SU3. The rest of the northern wall appeared to be cleaning up. As stated before, the floor of northern excavation area appeared to be cleaning up and several samples collected from this area were clean. Subsection 3.1 detail is provided in Figure 6.

Figure 6. SU3, Subsection 3.1 and 3.2 Detail

SU3, Subsection 3.1 Detail SU3, Subsection 3.2 Detail

SU3, Subsection 3.2

This is a contaminated lens of material located under a concrete pad. Other than this lens, this area appeared to be cleaning up. Again, the excavation floor below this area appeared clean. Subsection 3.2 detail is provided in Figure 6.

SU3, Subsection 3.3 & 3.4

This was the load out area for SU3. It slopes from the bottom of the excavation (7 to 8 feet bgs) up to about the surface elevation. Interviews with excavation control technicians and operators indicate that this area is not deeply contaminated however the SW wall of the excavation had yet to be established so this is speculative in nature. This area also includes a finger/lens of material (located directly under the words “ACO1 SU#3” in Figure 5) running under a concrete pad located on the southern boundary of the unit. This southern boundary area was otherwise cleaning up fairly well and it is believed that this will cleanup by pushing the excavation south by 10 to 15 feet along this particular portion of the southern boundary.

This subsection also contains the center berm, constructed of contaminated soil, running east to west through the center of the survey unit. This berm is 6 to 7 feet high, approximately 10 to 15 feet wide. It is likely that this material will washout during the shutdown period and lead to a thin coat of contamination residing throughout the floor areas of both the northern and southern half of the survey unit. Subsection 3.3 & 3.4 detail is provided in Figure 7.

Figure 7. SU3, Subsection 3.3 & 3.4 Detail

SU3, Subsection 3.5 & 3.6

Wooden Trough and Rail Bed

Much of the entire excavation wall running to the NE was contaminated. The excavation was limited by management in this direction due to concerns with undermining the rail line and because a water work around would need to be engineered to replace the wooden trough running between the rail line and the excavation area. The wooden trough is speculated to be contaminated because there were open pipes running from the excavation area directly into the trough. It is possible that contamination could extend beyond the wooden trough pushing the remediation into the rail bed but no evidence was found to indicate this to be the case. While some characterization was planned it this area it remained incomplete at project shut down.

SE Area of Trough

The south eastern portion of the wooden trough turns slightly south and into the remediation area.

Surface contamination was found on the eastern side of the trough as indicated by the red walkover gamma data. The depth and extent of the contamination is unknown but the hatched area on Figure 5 is believed to be a conservative estimate of the lateral extent. Subsection 3.5 & 3.6 detail is provided in Figure 8.

Figure 8. SU3, Subsections 3.5, 3.6, and 3.7 Detail

SU3, Subsection 3.5 & 3.6 Detail SU3, Subsection 3.7 Detail

SU3, Subsection 3.7

A live water line was encountered along the southern border of SU3. A small quantity of contaminated material remains around this pipe near locations were repairs were conducted. The rest of the southern boundary appeared to be cleaning up. Detail of Subsection 3.7 is provided in Figure 8.

SU3A, Subsection 3.A

The majority of SU3A has been remediated. The survey area was expanded to include that within the exclusion zone boundary. A concrete pad occupies the NE quadrant and it is believed that no contamination runs under the pad, however this remained to be confirmed at project shutdown. The western half has been excavated but it is not clean. The center green spot (within the hatched area on Figure 9) is the location a monitoring well that has been grouted closed and readied for removal.

Contamination may run west into the central drainage ditch however interviews with site personnel indicates that DuPont excavated and upgraded the drainage ditch at some point in the recent past and thus it may be clean. How this ditch cleaning activity impacted contamination locations is unknown.

However, to conservatively allow for some excavation of the ditch the estimated size of area 3.B (discussed next) was expanded to account for expansion from SU3A. Detail of Subsection 3.A is provided in Figure 9.

SU3A, Subsection 3.B

Subsection 3.B is a small area (maybe a fewmeters square) occupying and area across the central drainage ditch from SU3A. The area of contamination is located just under a steam line pressure valve port. The area has not been characterized and it is not known if the area exceeds the RG. The horizontal extent has been conservatively estimated to account for potential over run from SU3A, heading west and potentially linking with 3.B. Detail of subsection 3.B is provided in Figure 9.

Figure 9. SU3A, Subsection 3.A and 3.B detail

SU3A, Subsection 3.A Detail SU3A, Subsection 3.B Detail

SU3A, Subsection 3.C

Based upon visual observations, Subsection 3.Cmay be fill material, collected from thematerial associated with SU3A, and placed as a rail line crossing at this location. It is possible that this material is only inches deep however the true depth and horizontal extent of the contamination has not been defined. The activity level of this material has not been confirmed. Detail of Subsection 3.C is provided in Figure 10.

Figure 10. SU3A, Subsection 3.C Detail

SU3A, Subsection 3.D

Subsection 3.D was flagged for further investigation which, as of project shutdown, had not occurred. The baseline workover gamma surveys indicated that this area contained material with a higher background than that found throughout the rest of controlled area. It is possible that this area became cross contaminated during the central ditch clean out activities conducted by DuPont in the recent past.

However, this area is covered in gravel and surface samples did not indicate uranium levels above background. The characterization plan included pulling back the gravel layer at 2 or 3 10 foot square locations such that the subsurface soil could be checked. There is a potential that uranium contamination at levels above the RG will be found and thus a conservative estimate of the contamination volume has been estimated. Subsection 3.D detail is provided in Figure 11.

Figure 11. SU3A, Subsection 3.D Detail

AOC 2

AOC 2 is bounded by the Central Drainage ditch on 3 sides (N, E, and W) and by the Contaminated Water Treatment Plant (CWTP) to the south. The area is covered with an asphalt cap. Initial walkover surveys found no surface contamination in this area other than what was located in the exposed sides of the drainage ditch (seen as hot spots along the ditch leading to the railway bridge NE of the AOC). A small circular excavation area is located just west of the Central Drainage ditch which is depicted in the south central portion of Figure 12.

AOC 2 Remediation and As Left Status

In the fall of 2014, AOC 2 was test pitted to a depth of 2 feet bgs in the eastern half (where excavation is anticipated to be relatively shallow) and to 4 feet bgs in the western half (where excavations are planned to a depth of 12 feet). Both halves were found to be non RCRA with pockets of higher concentration uranium bearing material. The western half is known to contain petroleum distillates at depth (greater than the 4’ initial test pit depth) and thus this initial waste determination may not be applicable beyond the planned shallow excavation. The test pitting process involved removing the asphalt cover in several locations. At three of these locations located in the western half of AOC 2, contamination was brought to surface and can be seen as small hot spots above the 12’ primary cutline excavation area (Figure 12).

Figure 12. AOC 2, As Left Status

Sheet piling was driven around the 12 foot bgs primary excavation area (Figure 12) to support excavation water management activities during remediation. The sheet pile was installed by excavating a 6’ deep trench along the install lines. Significant quantities of concrete block, footers, and construction debris were encountered during much of the trenching. All trench material was loaded out and moved to the waste Transfer Facility (WTF) for off site disposal. The trench was then backfilled with clean soil. The sheet piling was driven through this clean material to design depth (40 to 60 feet bgs depending on location). Some uranium contamination was encountered during this process and can be seen as small hot spot along the outer side of upper eastern side of the sheep pile trench.

Other than the test pits and the trenched areas, AOC 2 remains largely covered with the original asphalt cap and/or gravel. The sheet pile area was bounded off and posted as a Contamination Area. A final perimeter gamma walkover survey is provided as Figure 13. In the rest of AOC 2, only the small areas that were test pitted in the eastern half of the unit were bounded off – this allowed construction traffic access to SU3 and SU3A during remediation.

AOC 2 Remaining Activities

AOC 2 was maintained largely intact during 2015 to allow support access for remedial activates occurring at SU3 and SU3A. A logistical strategy will need to be developed to deal with several issues presented by this area including:

Site drainage around this area will need to be maintained during remediation.

Access to the WTF (or another waste load out facility) will need to be maintained during remediation.

Significant water intrusion.

Access to the CWTP will need to be maintained during remediation.

An 18” water main is surrounds the western half of the AOC – care when working near this main is required.

The chemical constituents associated with the 12’ bgs excavation areamay be such that an overall containment facility or a very large exclusion zone be established.

Final field gamma surveys and samples (or another acceptable scheme) will have to be developed to assess the area against the RG.

Excavation activities near the rail line could present rail way bridge integrity concerns.

Figure 13. AOC 2, Final Perimeter GammaWalkover Survey

Figure 14. Waste Transfer Facility

Waste Transfer Facility (WTF)

Waste Transfer Facility Construction and As Left Status

TheWTF occupies a location formally used by DuPont as a rail load/off load area just north of AOC 2. The area was prepared by placing a gravel base and leveling the lot. A large block concrete wall was constructed to a height of approximately 5.5 feet around the area. An entry ramp is located along the SE boundary. An elevated dump ramp is located along the indented portion of the SE boundary. The WTF contains several sump pump locations. The NE half of the WTF was maintained as a contaminated area during the project. At project end, the contaminated asphalt was power washed, radiological direct and removable surveys were performed, and the area was down posted from a Contamination Area. A final gamma walkover survey of the area was performed and the result is provided as Figure 14. Note that the asphalt could be volumetrically contaminated and the end state plan for this area was to excavate the asphalt and remove it as waste; the subgrade would be free released as a MARSSIM Class I area. The SW half of the WTF was maintained in a clean state throughout site operations. The rail line, just outside of the WTF was also surveyed (direct and removable measurements) and found to be clean. This area was maintained as a clean area throughout the project. During loading operations it would be temporarily up posted to a Contamination Area. Once loading was complete and the waste containment bags were closed and sealed, the area would be down posted. The as left gamma walkover survey of this area is provided as Figure 15. Note that the “blue” readings are up against the concrete wall which increases nature gamma background due the structural geometry in which the measurements were collected.

Figure 15. Rail Loadout Area

Haul Roads

Baseline and project end haul road surveys were conducted along the haul rout from AOC 6 to the WTF.

During the baseline survey one questionable area was discovered. This area was surveyed again to confirm the elevated gamma readings found – these were confirmed. The area appeared to be associated with an asphalt patch. The elevated readings could be due to natural rock used in/under the patched area or it is possible that uranium was spilled at this location at some point in the past. This area was set aside for future investigation which had not been conducted at project end. The overall route with associated gamma data is provided in Figure 16. A detail drawing of the “as found” elevated area is provided as Figure 17.

Figure 16. As Left Haul Road Survey

Entrance Ramp

Dump Ramp

ContaminatedWater Treatment Plant (CWTP)

A baseline survey of the CWTP footprint was conducted prior to site operations. This survey was not GPS recorded however no contamination was found. The CTWP was constructed by ringing the area in jersey barrier. Aggregate was placed within the jersey barrier and graded to drain towards sumps located in the four corners of the area. The area was internally lined with an impermeable material which was draped out over the jersey barriers and secured to form secondary containment. Protective rock was then placed over the lining upon which the CWTP was constructed. The CWTP took in water at the SE modular tank.

This water was processed through an oil separator and then through a series of various filters and settling tanks. Process items that were potentially internally contaminated were labeled as Radioactive Materials Areas. Due to the large quantities of water processed, and the relatively low solubility of uranium, the potential for cross contamination in water is/was very low. However certain process (e.g., ion extraction resin columns) could concentrate radioactive material. Prior to shutdown, the CWTP was drained and clean water was processed through the system. All filter vessels were left with water and media in them so that the plant could be brought back to operation with minimal effort. The effluent side of the CTWP is considered the “clean” side with very low potential for cross contamination due to uranium. An item of note – much of the CTWP equipment came used to the DuPont site. When the CTWP first started operations there was a certain amount of flushing of built up scale (containing naturally occurring radioactive potassium, K 40) that had dried out and had become mobile during its non operating down time. Thus, initial K 40, and associated gross beta levels were elevated during initial operations. These values dropped fairly rapidly once the CWTP was in full operation.

Figure 17. Detail of As Found Elevated Area along Haul Route

Trailers and Storage Units

Four office trailers remain on site. These are located NW of AOC 2; see Figure 18. These trailers include:

Rad Operations Trailer (ARS on Figure 18) – This trailer was set up to provide chemical and radiological sample management, HPGe counting, smear and air counting, storage for radiological instrumentation, daily performance check operations, and general work space.

Craft Trailer (Craft on Figure 18) – Tool area, central break/meeting room, office area.

Contractor Trailer (ECC on Figure 18) – General office work space.

USACE Trailer (USACE on Figure 18) – Office space at each end with a central meeting area.

All four trailers are wired for internet and power. All but the Rad ops trailer contain operable indoor toilets serviceable through a black water system which is periodically pumped out via a portable toilet service. Presently the trailers cannot be removed from site without altering the sheet pile configuration in AOC 2. A steam line runs behind (NW) of the trailers under which personal and lower profile vehicles can access the site. Vehicles can also access the trailer area by driving around AOC 2, by the CWTP, and proceeding over the bridge just SW of the WTF.

Figure 18. Office Trailer Locations

There are four intermodal type storage containers on site. Two near the office trailers and two near the west corner of theWTF. A portion of one of the intermodals near theWTF has been set up as a radioactive materials area and contains items that were not free released at project end (e.g., hoses, water hose coupling gear).

Yardage Summary

Figure 19 provides the yardage summary for the site. This summary provides a reasonably conservative estimate of in site cubic yards of contaminated material remaining to be excavated (Figure 19, Column C4). Note that column C5 is the in situ yards, multiplied by an expansion factor of 1.3, for ex situ yards to be handled. Drawings of the areas from where these values are drawn are provided in Figure 3 (SU5), Figure 5 (SU3, SU3A), and Figure 12 (AOC 2). Details of these figures are provided in the sections addressing the individual AOCs.

Figure 19. DuPont Chambers Works Site Remediation Yardage Summary, November 24, 2015

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