ML17347A198

Usnrc Comments and Usace Responses Re Springfield Dam SAP

ML17347A198
Person / Time
Site:	West Valley Demonstration Project
Issue date:	07/18/2017
From:	Division of Decommissioning, Uranium Recovery and Waste Programs
To:	US Dept of the Army, Corps of Engineers, Buffalo District
AMSnyder NMSS/DUWP/MDB 5th floor
Shared Package
ML17347A124	List: ML17347A125 ML17347A142 ML17347A152 ML17347A198
References
Download: ML17347A198 (8)

Text

USACE - Buffalo District Springville Dam Sediment SAP USNRC Comment / USCE Response Memo

18-JUL-2017

The following responses to the USNRC comments are reflected also in the updated SAP text and tables. We hope these responses meet the need of USNRC, who provided pertinent input to advance the SAP. Please also see the text and table updates in the updated SAP (attached under same transmission email).

USNRC Comments and Questions The United States Army Corps of Engineers (USACE), "Design-Level Sediment Sampling and Analysis Plan Springville Dam and Cattaraugus Creek Sediment Sampling," prepared by: USACE Buffalo District, 1776 Niagara Street, Buffalo, N.Y. 14207, dated December 2016.

1. Sampling method Page 9 "The sediment sampling method will include a USACE-contracted hollow-stem auger drill rig that will continuously advance a minimum diameter 2-inch split spoon sampler to collect sediment throughout the vertical profile at each targeted location (i.e., the USACE drilling contracts include options for larger diameter split spoons that would produce larger sample volumes to meet laboratory needs)."

Page 10 "The anticipated volume of sediment required to fill all laboratory-supplied containers for each method listed in Table 2 data should not be problematic with the 2- inch diameter (or greater) split-spoon sampler and composite sampling method. Should extremely poor sediment recovery occur at any given location, a nearby alternative location will be selected by the on-site USACE technical representative to meet project goals. High-percentage core recovery is a priority for the sampling program, thus core recovery and sample number will be maximized via contingency penetrations that will be included in the drilling contract. For example, the contract will have a specific number of optional penetrations that would be actuated during the drilling period in accordance with the Triad philosophy, which is available at the following link: http://www.itrcweb.org/Guidance/GetDocument?documentID=90." Comment: It appears that thought was given to the sampling method to ensure that a sufficient number of samples and sufficient sample volume of material will be collected considering previous problems with SOMAT's (a contractor) use of the vibracore method for collecting samples in earlier investigations. NRC Question: How confident is USACE that the hollow stem auger and split spoon sampling method will be successful in obtaining representative samples for the full volume of the dredged prism?

USACE Response: The USACE performed geotechnical drilling in the fill and native sediments adjacent to the dam to ensure local soils would not impact design and construction (i.e., ensure no liquefiable soils or unstable layers exist in the construction area). Split spoon samples were retrieved successfully using a hollow-stem auger (HSA) drill rig with a standard split-spoon driver (e.g., 140-pound hydraulic hammer that also provides standard penetration values). One sentence was added to Page 9: "Previous geotechnical sampling of fill and sediment adjacent to the dam indicates the sample retrieval method (wide-diameter split spoon) provides adequate sediment volumes."

NRC Question/Request: The sampling plan should also explicitly state if there is any expected bias in the collection of samples given the sampling methodology and the acceptability of such bias for the beneficial use determination (BUD) (e.g., finer grained materials that may have higher concentrations of constituents of concern).

USACE Response: The USACE anticipates the future dredging action (more accurately an earth-moving action) would be conducted in 4-foot to 6-foot lifts (layers) until the design criteria (bed elevations) are met. The sediment excavation would be a bulk removal action that normally homogenizes the material due to multiple handling (e.g., excavator loads an articulated dump truck that moves sediment to a dewatering area, where it is later reloaded into dump trucks for final disposition under the selected BUD, which may include subsequent mixing and spreading). Consequently, the USACE plans to mimic this process in the sampling method by homogenizing the three 2-foot split spoons in a target 6-foot interval, irrespective of grain-size variations. The USACE does not intend to bias sampling based upon sediment texture, although we understand the desire to have such discreet samples. The USACE also plans to later submit a contingency abstract and flow chart to the stakeholder group should a given interval/location exhibit elevated concentrations. We are hoping to achieve this in parallel with the sampling effort. Section 5.2 (5 th paragraph) of the SAP was edited to reflect this input: "Generally, sediment samples will be targeted and collected from all locations shown in Figure 2. These locations are intended to provide representative samples of the dredge prism (interior and exterior) outlined in Figure 1. The vertical profiling will be completed by combining three split-spoon sample intervals (totaling 6 feet of penetration) into one field container (clean stainless steel bowl), which are then homogenized to emulate the mixing of dredge material during sediment excavation, handling, dewatering, and transportation for disposition under a BUD. The USACE will not collect discreet vertical samples, but rely on the vertical 6-foot composite to produce the sediment volume that will be placed into the respective laboratory containers. The current USACE drilling contract provides the option to use a 24-inch long split spoon, so the composite intervals will be in 6-foot depth increments."

2. Page 12, Human Health Risk "Previous analytical data generated in 2007 and 2011 indicated surface and near- surface sediments both upstream and downstream of the Springville Dam are not impacted with chemical or radiologic elements that pose a risk to human health and the environment."

Comment: The statement in the Executive Summary and Page 10 about the low human health risk is based on the measure of risk utilized in the study. Please clarify the basis for the statement in the SAP and specifically the measure used to assess risk. USACE Response: The USACE updated Section 6.2 with the following text (first two paragraphs) to address this comment: "Previous analytical data generated in 2007 and 2011 indicated surface and near-surface sediments both upstream and downstream of the Springville Dam are not impacted with chemical or radiologic elements that pose a risk to human health and the environment. The USACE design package that serves as a basis for the stakeholder cost-share agreement, "Springville (Scoby) Dam Fish Passage Project - Detailed Project Report and Environmental Assessment" (USACE 2015 - add to list) includes a Phase I Environmental Site Assessment as Appendix 4. This appendix provides a combined analysis of sediment, water, and fish data collected near the dam and determined that a Construction Worker receptor will not be exposed to hazardous or radiologic materials that would pose an unacceptable risk throughout construction.

Comparative standards for chemicals include USEPA regional screening levels for both residential and industrial environments (USEPA 2012) and NYSDEC values for soil remediation (NYSDEC 2006). For radionuclides , the EPA's preliminary remediation goals (PRG) for both residential and outdoor workers were used (USEPA 2010). Like the chemical risk-based screening levels, these were developed to meet the lower end of the EPA's acceptable range of extra cancer risks, i.e., 1 in a million. The outdoor worker PRG assumes that a worker spends 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> a day, 225 days a year at the si te for a total of 25 years whereas the residential soil PRG assumes that a person spends 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day, 350 days a year for a total of 30 years at the site. The construction at the Scoby Dam is not expected to last longer than 18 months, so the Construction Worker would not be exposed to unacceptable risk."

3. Page 15, Screening Approach "Sediment obtained from the subsurface intervals will be screened with the following field instruments:

1. Photo-ionizing detector (PID) to detect chlorinated solvents or alike chemicals;

2. Geiger-Mueller meter to detect alpha, beta, and gamma radiation; and

3. Sodium-iodide (NaI) scintillation detector to optimally detect gamma radiation.

The USACE also will consider the use of an alpha-beta phosphor sandwich (or phoswich) detector to distinguish between alpha and beta signatures in total radioactivity; such instruments include Ludlum 43-89 or 43-93 series detectors.

This screening step will occur when the sediment is exposed in the split spoon device and prior to homogenizing into a clean stainless steel bowl (see Section 4.2)."

Comment: Additional detail could be provided in the sediment Sampling and Analysis Plan (SAP) on the screening approach to be used in the field for radionuclides of interest and their basis. Screening value ranges are provided in Table 3, but those screening criteria appear to be based on comparison to analytical results. The field screening methods to be used in conjunction with the Geiger-Mueller and Sodium-Iodide detectors for radiological constituents do not appear to have a specified purpose or action limit in the SAP.

USACE Response: Section 8.1 (last half) was significantly updated based upon the comment. I will not copy the text here due to length, but please see the accompanying red-lined MS Word version submitted with these responses. Please let us know if we met the reviewer's intent.

4. Screening Levels Page 16 "The initial exposure risk and radiologic background criteria to be used for screening the analytical results are summarized in Table 3. These criteria will be used to provide approval of the case-specific BUD. The radiologic results will be screened against the WVDP-specific radionuclides that are listed for sediment in the 2012 WVDP Annual Site Environmental Report (ASER Table F-2E). The entire gamma spectroscopy library will be reported by the laboratory, but only WVDP-related radionuclides noted below Table 1 and listed on Table 3 will be assessed for the BUD."

Comment: Tables in Appendix F of the U.S. Department of Energy's (DOE's) 2012 Annual Site Environmental Report (ASER) are used as the basis for the list of radionuclides of interest for the BUD (see Table 1 below). The list is inconsistent with the radionuclides of interest cited in the West Valley Demonstration Project (WVDP) Decommissioning Plan (DP), Revision 2 (DOE, 2009), reproduced in Table 2 below. The list of 18 radionuclides of interest in the decommissioning plan are primarily based on risk significance or prevalence (e.g., high activity fractions of Sr-90 and Cs-137).

USACE should provide a clear rationale for the selection of the list of radionuclides which are the focus of the BUD. Most notably, hard-to-detect radionuclides such as C-14, I-129, and Tc-99, are not listed. Pu-241 is also not listed, but this radionuclide could possibly be inferred from analytical results for other Pu isotopes. Np-237 is similarly not listed but could possibly be quantified through the gamma spectroscopy analysis that will be performed. Please note that U.S. Nuclear Regulatory Commission (NRC) recognizes that the hard to detect radionuclides would be difficult to measure, are not expected to be dominant constituents in sediments given their relatively high solubility, or may not provide useful information on the presence of WVDP contamination in the sediments. The NRC suggests inclusion of gross alpha and gross beta analyses to demonstrate that radionuclides not specifically included in the analyses are not present at unusually high levels. Nonetheless, the basis for inclusion or exclusion of certain radionuclides of interest should be clarified.

USACE Response: Section 8.2, Table 1, and Table 3 were edited to include Gross Alpha and Gross Beta radioactivity. The other radionuclides discussed in the comment were not evaluated in the 2012 ASER, so no background ranges were developed for those radionuclides. This precludes a decision-making point in the sediment disposition process (i.e., do the reported values reflect a project-related [or known] background range that allows a BUD). Consequently, the USACE will evaluate the most significant radionuclides that would indicate WVDP-centric impacts (i.e., retain the current decision-making list in Table 3, plus gross alpha and beta).

The primary screening range, provided in Table 1 is based on background soil samples near a West Valley air monitor while the secondary screening range is based on background sediment concentrations near Bigelow Bridge. The selection of background soil locations for the primary screening range is unclear. A basis should be provided, as well as an explanation of the intended use of the primary versus the secondary screening ranges. Additionally, the plan should be clear to state the statistical approach to be used to compare the sediment concentrations to the screening values (e.g., sediment averages greater than two standard deviations above the background values provided in Table 3 of the SAP will be considered potentially impacted and will be subjected to further screening). Although the screening values, listed in Table 3 of the plan, are being used as "initial" screening values, it is unclear what follow-up approaches may be used to support the BUD in the event the background screening value ranges are exceeded (e.g., use of WVDP Phase 1 DP Derived Concentration Guideline Levels (DCGLs), NRC/Environmental Protection Agency (EPA) Memorandum of Understanding values, or NRC screening values [see Table F-1A in the DOE 2012 ASER]). Although the background values may be overly restrictive, use of alternative screening values should be justified consistent with the ultimate disposition of the materials (e.g., will sediments be used for construction projects or backfill). For example, use of sediment DCGLs cited in the WVDP DP, Rev. 2 (Table 2) may not be appropriate because certain assumptions went into the calculation of the DCGLs that may be invalid for the BUD.

USACE Response: Section 8.2, Table 1, and Table 3 were edited to expand the discussion on dataset comparisons to Table 3 entries. Please see the red-line version to determine the USACE has properly addressed this comment. Basically, the NYSDEC requires a background-like condition for dispositioning potential radiologic materials in NY State, thus risk-based conditions do not apply, but may be reserved for discussion with NYSDEC. In addition, Table 3 was updated to "swap" the primary radionuclide background criteria to sediment, whereas soil values will be the secondary criteria. Section 8.2 also includes wording regarding the action that could occur if the sampling data fail the screening tests.

Additionally, there appears to be an error in the Table 3 primary screening value for U- 232. Please consult the 2012 ASER for the correct value (the value should be 0.0034+/-0.0273 pCi/g). Table 1, Screening Levels for Beneficial Use Determination. Adapted from Table 3 in the USACE Sampling and Analysis Plan.

WVDP Rad S y mbol ScreeningRange (Primar y) Units Screening Range (Secondar y) Potassium-40 K-40 10.6+/-1.3pCi/g13.7+/-1.5 Cobalt-60 Co-60 0.0005+/-0.0261pCi/g0.0002+/-0.0162 Strontium-90 Sr-90 0.0349+/-0.0403pCi/g0.0004+/-0.0497 Cesium-137 Cs-137 0.350+/-0.058pCi/g0.0373+/-0.0227 Uranium-232 U-232 -0.0034.0273pCi/g0+/-0.0552 Uranium-233/234 U-233/234 0.80+/-0.120pCi/g0.542+/-0.119 Uranium-235/236 U-235/236 0.0371+/-0.0370pCi/g0.0573+/-0.0388 Uranium-238 U-238 1.01+/-0.13pCi/g0.53+/-0.114 Total Uranium Uranium 2.26+/-0.14mg/kg1.91+/-0.04 Plutonium-238 Pu-238 0.00275+/-0.00934pCi/g0.0111+/-0.0186 Plutonium-239/240 Pu-239/240 0.0165+/-0.0170 p Ci/g 0.0144+/-0.0144 Amercium-241 Am-241 0.0061+/-0.0106pCi/g0.017+/-0.0224 Note: Primary Screening Range is based on WVDP ASER 2012 (DOE 2013) Table F-2D, 10-year Average for Background Soil at Great Valley Air Monitor (Soil last collected in 2012 on five-year periodicity.) Secondary Screening Range is based on WVDP ASER 2012 (DOE 2013) Table F-2E, Bigelow Bridge 10-year Average for Cattaraugus Creek Background (Sediment last collected in 2012 on five-year periodicity.)

USACE Response: Thank you, Table 3 was updated. Table 2, West Valley Decommissioning Plan Radionuclides of Interest and DCGLs in pCi/g. Adapted from DOE's Phase 1 DP, Revision 2 (DOE, 2009)

Nuclide Surface Subsurface SedimentAm-241 2.90E+01 6.30E+031.00E+04C-14 1.60E+01 9.90E+021.80E+03Cm-243 3.50E+01 1.10E+033.10E+03Cm-244 6.50E+01 2.20E+043.80E+04 Cs- 137(2) 1.50E+01 3.00E+02 1.00E+03I-129 3.30E-01 7.50E+007.90E+02Np-237 2.60E-01 1.00E+003.20E+02Pu-238 4.00E+01 1.30E+041.20E+04Pu-239 2.50E+01 3.10E+031.20E+04Pu-240 2.60E+01 3.40E+031.20E+04Pu-241 1.20E+03 2.40E+053.40E+05Sr-90(2) 4.10E+00 2.80E+024.70E+03Tc-99 2.10E+01 5.90E+026.60E+05U-232 1.50E+00 7.40E+012.20E+02U-233 8.30E+00 1.90E+022.20E+04U-234 8.40E+00 2.00E+022.20E+04U-235 3.50E+00 2.10E+022.30E+03U-238 9.80E+00 2.10E+028.20E+03NOTES: (1) The DCGL W is the DCGL applicable to the average concentration over a survey unit. (2)

DCGLs for Sr-90 and Cs-137 apply to the year 2041 and later.

5. Source of Potential Contamination It is not possible to determine the source of residual radioactivity, if detected, based purely on localized sampling. If residual radioactivity is found, it is unclear whether the USACE will require additional sampling or take other actions to identify the source of radionuclides that are present in the samples. If residual radioactivity common to DOE operations and the former reprocessing plant are found above background, it may be difficult to identify the source or the residual radioactivity.

The USACE infers in its plan that the WVDP is the only potential source of radionuclides that might be found in the sediment due to its proximity to the Springville Dam. Also, the USACE, in its plan, references the DOE WVDP ASER; however the ASER documents DOE's environmental surveillance program, which is specific to DOE operations. The USACE should address the possibility of any other potential sources of radioactivity such as the radioactivity due to past releases from the former West Valley reprocessing plant; any other activity due to effluent discharges in the region that may be due to New York State licensed material (other licensees and the State Licensed Disposal Facility); radioactivity due to fall-out from nuclear weapons testing; and other naturally occurring radionuclides, especially those that are also noted as WVDP radionuclides. If USACE does not plan on discussing other potential sources, then the USACE should explain why the USACE is only focused on the WVDP. As indicated in the USACE email dated December 20, 2016, the SAP does not include contingency actions, but the USACE intends to develop a separate document to address contingency actions and plans to provide it to the NRC for courtesy review at a later date. It is unclear whether there is a mechanism to link contingency planning to field implementation and sample collection, especially if radionuclides common to the WVDP and the former reprocessing plant or any other licensed facilities are present above action levels.

USACE Response: Section 2.2 (first paragraph) was edited to include wording about the limited focus on the WVDP/WNYNSC. If radionuclides are above the Table 3 criteria and a BUD is not possible, then the USACE stance will be focused on the impacts to the Springville Dam project and not the responsible party that owns the impacts. This duty would be transferred to the proper State and Federal regulatory bodies. The USACE still plans to provide the stakeholder group with a brief contingency plan upon conclusion of this SAP.

6.1 Editorial

Comment Page 10, "The planned intervals (totaling four at each 11 locations) are listed below and will be sampled for the chemicals and radionuclides listed in Table 1:

1. One composite sample derived from the homogenization of all sediment retrieved from the top three split-spoon samples (nominally zero to 6.0 feet deep).

2. One composite sample derived from the homogenization of all sediment retrieved from the subsequent three samples (nominally 6.0 feet to 12.0 feet deep).

3. One composite sample derived from the homogenization of all sediment retrieved from the third set of three split-spoon samples (nominally 12.0 feet to 18.0 feet deep).

4. One composite sample derived from the homogenization of all sediment retrieved from the fourth set of three split-spoon samples (nominally 18.0 feet to 24.0 feet deep)."

Comment: Please clarify that not all of the 11 sample locations will be composited for each of the depth intervals (i.e., 4 composites representative of each of the 4 depth intervals) as the text on page 10 may imply this and could be made more clear. Table 2 and text on page 9 are clear to indicate that 44 samples will be analyzed.

USACE Response: Section 5.2 (fifth paragraph) was edited to include wording to clarify that sediment from different locations will not be composited.