ML20214N933
| ML20214N933 | |
| Person / Time | |
|---|---|
| Issue date: | 08/01/1986 |
| From: | Justus P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Knapp M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-86 NUDOCS 8609170175 | |
| Download: ML20214N933 (7) | |
Text
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.. PJustus j , m ,% ..E d) ._ _ WFord & r/f MFliegel MEMORANDUM FOR: Malcolm Knapp, Chief *F WMLU MHaisfield, WMLU JGrimm, WMGT FROM: Philip Justus, Acting Chief WMGT
SUBJECT:
REVIEW 0F DRAFT COMPARATIVE ANALYSIS OF DISPOSAL SITE ALTERNATIVES REPORT FOR THE SLICK ROCK SITE, TICKET WM86 628 Please find enclosed cur review of the Slick Rock Draft Comparative Analysis of Disposal Site Alternatives Report (CADSAR). DOE guidance states that the purpose of NRC's review of Draf t CADSARs is to confirm that remedial action options will meet EPA standards and to verify that key issues are resolved.
Pcwever, the Draft CADSAR is a very preliminary document, which is produced befcre much environmental data have been collected and before detailed engineering data are available. Verification that a site will meet EPA standards requires detailed environmental and engineering information.
Therefore, at the Draft CADSAR stage we cannot verify that rerredial actions will meet EPA standards or resolve many key issues. The purpose of our comments is to help identify major issues that must be addressed to obtain NRC concurrence in the Pemedial Action Plan. However, because of the limited infornation presented within the Draft CADSAR the issues identified may not be con:prehensive. New major concerns may be identified in reviews of future Slick Rock documents. If the scope of future Draft CADSARs is similar to the Slick Rock Draft CADSAR , future reviews will be conducted in the same manner that we have reviewed the Slick Rock Draft CADSAR.
Participants in this revicw were Terry Johnson (surface water), Paul Bembia (geochemistry), Joel Grimm (geology), Abou-Pakr Ibrahim (geophysics), and William Ford (geohydrology). Should ycu have any questions please contact me or William Ford (74697).
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NAME :WFord :MFliegel :JTrapp :KJackson :PJustu : :
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DATE :86/7/ :86/7/ :86/7/ :86/7/ :86 of : :
WM86/WHF/86/07/24 REVIEW 0F SLICK ROCK Draft CADSAR In conducting our review of the Draft Slick Rock Comparative Analysis of Disposal Site Alternatives Report (Draft CADSAR) we are only providing our -
comments and suggestions to help identify major issues early in the UMTRAP review process. However, since meeting the EPA standards is dependent on more .
detailed data collection and design information we can not confirm that the remedial action options included in the Draft CADSAR will meet EPA standards and that all key issues have been identified or resolved. Our review was further limited due to the fact that few of the Draft CADSAR references were available to the staff at the time of this review.
Section 2, Alternate Site Selection, Page 4 and Section 8, Recommendations Page 29 Through a site selection processes carried out with the State of Colorado, i -
stabilization of the tailings out of the floodplain, relocation to Burro Canyon, or relocat. ion to Pioneer Urban sites were selected. Pioneer Urban was not characterized (p. 4) and Burro Canyon site will not be further characterized (p. 29) beyond one hole drilled for geotechnical and hydrogeologic purposes. Based on these decisions, Stabilization on Site (SOS) is the only alternative which will receive further site characterization.
Therefore, while the purpose of the final Draft CADSAR is to evaluate and rark all remedial action alternatives, the draft Draft CADSAR has eliminated data-gatherirg reeds for all but one alternative. The justification for this will need to be provided in the Final CADSAR.
Section 2, Alternate Site Selection, Page 4 The DOE and State site selection processes do not identify stabilization-on-the-floodplain as an alternative. However, the Draft CADSAR, treats stabilization-on-the-floodplain as an alternative. This apparent ambiguity, should be explained.
j Section 3, Characterization of Sites, Page 5 Section 3 presents insufficient data on the significance of the bedrock aquifers as a source of water and support for the conclusion that bedrock aquifers will not be affected by any of the disposal alternatives. The effect of the tailings on bedrock aquifers could be a significant issue in determining compliance with the EPA standard. -
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j Section 3.1.2, Contaminant Distribution, Page 6 .
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l This section of the Slick Rock Draft CADSAR describes the location'of existing -
i contamination at the Slick Rock site. Contamination is described as being -
l present at (1) the tailings piles, (2) windblown materials off the piles, and
- (3) concrete foundations at the Union Carbide site. No mention, however, is ..
t made of ground water contamination present in alluvial gravels at the site (Page 12). This section of the Draft CADSAR should state that contamination is i
present in ground water and describe the location and areal extent of this
- contamination.
f Section 3, Tables 3.2 and 3.3, Pages 12-13
! The report states in Table 3.2 that the design earthquake is 0.2g, while in J Table 3.3 it states the bedrock acceleration is 0.2 g. More infonnation is .
needed on how these values were determined and the rationale for using 0.2g i
i rather than ano'ther value. The report should also clarify if the bediock j acceleration (Table,3.3) is meant to be equivalent to the design earth quake acceleration (Table 3.2). These two terms can be interpreted differently.
l Consistency in the terminology should be used through out the report.
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! Section 4.3, Stabilization at the Burro Canyon Site, Page 19 I
l The Draft CADSAR provides detailed maps of the SIP and the SOS alternatives,
{ but does not contain any detailed map of the Burro Canyon site. A map should be included, since this is the second choice from a cost stand point, and j because it would be very helpful in understanding statements such as "The i surrounding terrain would be graded to direct flow away from the pile" and "The i impact on the Burro Canyon site of the PMF in Nicholas Wash must also be
, evaluated". Flood studies and nosion protection analyses should also be i provided for this site, since the cost of flood protection will likely constitute a large portion of the costs for this alternative. '
- Section 4.2, Stabilization on Site, Page 19 and Figure 4.2 Figure 4.2 indicates that at the SOS alternative the slopes are steep, uneven, j and consist of several arroyos and bedrock spurs. This alternative may require
- considerable changes in natural slopes to accommodate the noved tailings and i carefully planned drainage controls and diversions will probably be required to j maintain the geomorphic stability of the tailings after site closure. ,
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r WM86/WHF/86/07/24 Section 5, Significant Issues, Page 21 . .
The Draft CADSAR does not identify several significant ground water issues that could affect the selection of an appropriate alternative and should be .
considered in determining if any of the sites will meet EPA standards. The issues are: .,
- 1. Will the tailings be a potential source of future ground water contamination?
- 2. Will location at the SIP and SOS sites cause ground water pollution, because the tailings will be exposed to more water either from flooding, increased runoff from surrounding hill sides, or higher ground water levels?
3.. Will any of the sites require a liner underneath the pil,e to preven.t future ground water contamination?
- 4. Will any of the sites present a ground water contamination threat to regional ground water aquifers?
- 5. Will any of the alternatives present a local threat to the public frcm ground water contamination? Specifically, what are the sources of water for the gas sweetener plant and the trailer park immediately adjacent to the SIP and SOS alternatives?
- 6. Will there be a need for ground water restoration?
Section 5.3, Surface Drainage Impacts, Page 21 The Draft CADSAR mentions that potential surface drainage impacts (depending on the alternative chosen) may exist for the drainage basins of Summit Canyon, Corral Draw, and Nicholas Wash. These basins are not shown on any of the Draft CADSAR figures. The staff was therefore not able to provide comments on the potential surface water impacts on these basins from various alternatives.
Section 5, Significant Issues, Page 21 .
The report cites information on faults within five miles of the Slick Rock Site it without citing the is impossible sourcethe to verify for validity this information. Without knowing of the information. the basis,'the Clarification e5.
impact of faulting on the engineering design is also needed.
KM86/WHF/86/07/24 Section 6, Cost Estimates, Page 22 The SIP alternative appears to underestimate restoration costs, because (1) probable maximum flood (PMF) river velocities of 29 ft/sec will probably require a rock cover on the pile of greater than 24" diameter rock, (2) -
upstream velocities of 8-9 ft/sec are dependent on stabilizing the downstream constricted section, which may result in costly and extensive engineering -
design measures and (3) erosion protection measures in the small arroyos were not addressed in the Draft CADSAR and will likely require somewhat elaborate diversion structures. Additional flood studies and riprap designs need to be performed to better assess the costs of erosion protection for this option, since it serves as a basis for comparison with other options.
Section 6, Cost Estimates, Page 22 Cost estimates for the SOS and the Burro Canyon Site alternatives appear to be
. underestimated. Costs that may not have been considered are (1) erosion protection in the arroyos, (2) slope stabilization below the embank' ment toe, (3) river meander protection, and (4) slope stabilization and diversion ditches. This information should be provided in as much detail as possible.
Section 6, Cost Estimates, Page 22 The Draft CADSAR provides information relating to the costs of protection for 50% of a PMF. The NRC staff does not consider it appropriate to essess costs for a flood less than a PMF without also assessing the costs of protection for a PMF. Furthermore, sufficient information has not been developed to reasonably assess the costs of protecting for a full PMF. Additionally we conclude that 50% of a PMF will probably not provide adequate protection to meet EPA standards.
Section 6, Cost Estimates, Page 24 The Draft CADSAR is deficient in the preparation of preliminary reclamation cost estimates. While the draft Draft CADSAR is a document that is to be prepared using mostly literature and preliminary data, more data are generally needed to reach initial estimates of costs associated with PMF protection. At a minimum, initial calculation of peak flow rates, elevations, and flow .
velocities for all streams and diversion channels should be provided. In addition, preliminary rock durability information should be based on more than visual observation, because costs may tie dependent on the selection of rogk with acceptable durability.
WM86/WHF/86/07/24 Section 6, Table 7.2, Page 28 .
Table 7.2 contains a tabulation of risks associated with each restoration alternative. However, the table does not explain or reference how the risks .
were determined. The report should clarify how these probabilities were determined. ..
Section 7, Table 7.1, Page 26 Conditions of sediment deposition are identified in the Draft CADSAR as a positive technical factor for the Burro Canyon site alternative. The reviewer assumes these conditions involve fluvial and/or eolian deposition. These conditions cannot be considered a positive technical factor without an evaluation of their effects. Depositional conditions may result in aggradation and blockage of engineered drainage systems, which could require either specific designs to reduce or eliminate sedimentation or active . site
- maintenance after closure.
Section 7, Table 7.1, Page 26 The negative technical factor of habitat disturbance at the Burro Canyon alternate site has been omitted from the table of alternatives comparison.
Section 8, Recommendations, Page 29 The Draft CADSAR states that a field characterization program will not be conducted at the Burro Canyon site unless " constraints are found which would require relocation of the tailings to an alternate site". However, the Draft CADSAR does not define what constraints would require relocation and consideration of alternative sites. For example, if only the SIP and SOS options are studied, additional data may result in higher cost estimates than for the Burro Canyon alternative. If no technical constraints are found for the SIP and SOS options, then the cheaper alternative (in this case Burro Canyon) may never be considered.
Section 8, Reconnendations, Page 29 The field characterization program will not evaluate the Burro Canyon site' unless " constraints are found which would require relocation of the tailings to an alternate site". The problem is that the Draft CADSAR lists the impact on the Burro Canyon site of the PMF (Page 21) as a significant issue and indlc'ates that the site overlies the Dakota Sandstone, which in many areas of the west is considered a major regional aquifer. Since these issues could significantly
WM86/'4HF/86/07/24 effect the suitability of the site it is suggested that, at a minimum, the site should have some additional work performed to better define: (1) the effects of . .
a PMF, (2) the significance of the Dakota Sandstone as a ground water resource in the area, and (3) the estimated thickness of low permeability rock material between the Dakota Sandstone and the proposed pile location. -
Section 8, Recommendations, Page 29 _.
According to UMTRA Project Site Management Manual (DOE, 1986) the Draft CADSAR l should (among other things) provide the basis for DOE, NRC, and affected states and tribes to " agree on site characterization data requirements." The Draft CADSAR states that it presents a description of the field characteriza; ion program "needed to prepare the final Draft CADSAR and to select +he preferred alternative." The description of the characterization program given .n the Draft CADSAR, however, consists only of the number of geotechnical m**
hydrological borings to be performed and the number of test pits to L dug to characterize the SOS and SIP alternatives (no characterization is pit.med it the Burro Canyon site at'this time). Since no details of the site characterization plans or planned data gathering are included in the Draft CADSAR, and because none of the references cited were available for staff review, the NRC staff cannot assess whether such plans are adequate to assure that the sites will be properly characterized.
REFERENCES CITED DOE, 1986, UMTRA Project Site Manual, May 1986 I
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