CONCLUSIONS AND DISCUSSION

  1. Available site sampling and monitoring information indicates that there is no immediate hazard to the off-site public from the residues in their present configuration.

A variety of sources of risk must be considered, including those from contaminants in the air, soil, and water. Potential contaminants in the air include 222Rn, volatile organic compounds (VOCs), and airborne particulates; in the water and soil, potential contaminants could include radioactive and toxic inorganic and organic chemicals.

The radionuclides 226Ra (and its daughters) and 230Th in the K-65 residues are the principal radioactive contaminants at NFSS. In addition to amounts, consideration of the properties of the materials that contain the 226Ra and 230Th is important to determine to a large extent the physical and chemical behavior of those elements in and around the waste containment facility, as well as the behavior of their decay daughters. The daughter product of 226Ra of greatest importance with respect to the safety of the off-site public is 222Rn.

The fact that radon is a noble gas means, first, that it is not reactive with other chemicals to produce an immotile non-gaseous compound, and second, that its safe containment in a permeable burial system such as exists at NFSS must rely on its short half-life (3.82 days) and its decay to non-gaseous daughters. Therefore, if the diffusion path of 222Rn from the residues is such that it takes on the order of 38 days (about 10 decay half-lives) before it leaves the protective cap, the amount reaching the air above the cap will be reduced about 1,000-fold. It is, therefore, highly desirable to have a cap on the residues that imposes a residence time of the 222Rn in the cap that is long relative to the 222Rn half life. Air monitoring results to date show that radon activity levels are well within acceptable levels for breathing, both on the NFSS and in surrounding areas.

Water samples from monitoring wells on the site and in surrounding areas show that radioactive species have not entered the ground water system in amounts much in excess of background levels, and that their concentrations are well within acceptable limits. Soil samples taken around the site show small amounts of radioactive contamination, especially where residues and wastes were stored in drums on the surface prior to consolidation and more permanent storage. However, the levels of radioactivity are so low as to be of negligible concern.

For all of the alternatives considered, the health risks from radiation estimated in the 1986 FEIS are stated to be negligible both for the general public and for workers involved in operations required to carry out the alternatives. The calculated on-site well contamination by 226Ra, 1,000 years after burial of the residues, ranges from none for Alternatives 3a, 3b, 4b and 4d to 1,100 pCi/l for Alternative 1; the on-site well contamination by 226Ra reaches peak concentrations at the times shown in Table 4.



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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK CONCLUSIONS AND DISCUSSION Available site sampling and monitoring information indicates that there is no immediate hazard to the off-site public from the residues in their present configuration. A variety of sources of risk must be considered, including those from contaminants in the air, soil, and water. Potential contaminants in the air include 222Rn, volatile organic compounds (VOCs), and airborne particulates; in the water and soil, potential contaminants could include radioactive and toxic inorganic and organic chemicals. The radionuclides 226Ra (and its daughters) and 230Th in the K-65 residues are the principal radioactive contaminants at NFSS. In addition to amounts, consideration of the properties of the materials that contain the 226Ra and 230Th is important to determine to a large extent the physical and chemical behavior of those elements in and around the waste containment facility, as well as the behavior of their decay daughters. The daughter product of 226Ra of greatest importance with respect to the safety of the off-site public is 222Rn. The fact that radon is a noble gas means, first, that it is not reactive with other chemicals to produce an immotile non-gaseous compound, and second, that its safe containment in a permeable burial system such as exists at NFSS must rely on its short half-life (3.82 days) and its decay to non-gaseous daughters. Therefore, if the diffusion path of 222Rn from the residues is such that it takes on the order of 38 days (about 10 decay half-lives) before it leaves the protective cap, the amount reaching the air above the cap will be reduced about 1,000-fold. It is, therefore, highly desirable to have a cap on the residues that imposes a residence time of the 222Rn in the cap that is long relative to the 222Rn half life. Air monitoring results to date show that radon activity levels are well within acceptable levels for breathing, both on the NFSS and in surrounding areas. Water samples from monitoring wells on the site and in surrounding areas show that radioactive species have not entered the ground water system in amounts much in excess of background levels, and that their concentrations are well within acceptable limits. Soil samples taken around the site show small amounts of radioactive contamination, especially where residues and wastes were stored in drums on the surface prior to consolidation and more permanent storage. However, the levels of radioactivity are so low as to be of negligible concern. For all of the alternatives considered, the health risks from radiation estimated in the 1986 FEIS are stated to be negligible both for the general public and for workers involved in operations required to carry out the alternatives. The calculated on-site well contamination by 226Ra, 1,000 years after burial of the residues, ranges from none for Alternatives 3a, 3b, 4b and 4d to 1,100 pCi/l for Alternative 1; the on-site well contamination by 226Ra reaches peak concentrations at the times shown in Table 4.

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK TABLE 4. Peak 226Ra Concentrations and Times of Occurrence (U.S. Department of Energy, 1986, Table 2.2, pp 2-4 abd 2-5) Alternative Concentration 1000 years from now, pCi/l Time to reach maximum concentration, years 1 1,100 1,800 2a 380 3,600 2b 42 3,600 3a none 35,000 3b none 7,000 4a Hanford-none; NFSS-3.6 Hanford-35,000; NFSS-3,600 4b none Hanford-35,000 4c Oak Ridge-none; NFSS-3.6 Oak Ridge-7,000; NFSS-3,600 4d none Oak Ridge-7,000 Source: U.S. Department of Energy, 1986 (Table 2.2, pp 2-4 and 2-5)

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK The high-level residues (i.e., those classified as K-65, L-30/F-32 combined, and L-50) pose a potential long-term risk to the public, given the existing environmental conditions and future unpredictability, if they are left permanently at the NFSS. The continuing high levels of radioactivity of the K-65 residues, the cumulative uncertainties in understanding and predicting local geological and hydrological behavior, the indeterminate nature of future land and water use and future demographics, the unpredictable physicochemical behavior of the residues such as possible complexation with reactants in the soil and colloid or pseudocolloid formation, and the large potential risk to the public, all argue decisively against leaving the residues at the NFSS permanently. Although the Committee considers containment-in-place of radioactive waste protected by engineered barriers as a potentially acceptable technology, it recognizes that the source and its configuration, environmental conditions, and potential long-term risks to public and environmental safety and health are unique to each site. Thus, the applicability of containment-in-place must be based on site-specific factors. The extraordinarily high concentrations of radium and its daughters, especially of radon, and the presence of substantial concentrations of 230Th with a half life of 75,400 years dictate that a potential for unacceptable radiation exposure will remain for a time far in excess of the 1,600-year half life of 226Ra. Incomplete knowledge of the details of the local geology (e.g., of the presence and extent of sand lenses in the glacial clays and of pathways for radium-laden water to reach underlying rock layers where it could be channeled away from the site) is cause for concern about the adequacy of coverage of this issue in the 1986 FEIS. This concern is compounded by the realization that ground water seasonally intrudes the residues, and that pumping activities at the adjacent landfill alter the flow pattern of the ground water (Bechtel National, Inc., personal communication). The possibility of home construction and other types of human occupancy and land use near and on the site long after the period of site maintenance, monitoring, and institutional control has expired must be taken very seriously, considering the potential consequences of intrusion into or exposure of the buried K-65 residues. Finally, the uncertainty in predicting the long-term physicochemical behavior of the residues in the complex matrix of clay, as well as the behavior of sulfate salts of the radium, thorium, lead, and other components of the residues, makes for an uncertain prediction of the behavior and thus of the long-term safety of the NFSS. Contamination of the surface soil occurred primarily during storage on the ground of the R-10 residues before they were moved into the Wastes Containment Structure. This would be a problem only if an intruder, such as a child, ingested small amounts of the soil. It does, however, lead to residual contamination on the site that may interfere with

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK monitoring measurements and potentially lead to erroneous conclusions about what is happening to the NFSS residues. In the 1986 FEIS, it is assumed that a farm pond is constructed immediately downstream of the waste-containment area. It is also assumed that the pile of contaminated materials is the entire watershed for the pond, that the cap has been entirely lost, and that 100 mg/l of suspended solids in the pond originate from the contaminated materials. Estimates of concentrations in surface water of dissolved and particulate forms of inorganic and organic substances are given in the 1986 FEIS (U.S. Department of Energy, 1986, Section 4.4.3.1, p. 4-73 to 4-81). The dissolved concentrations include contributions from both surface runoff and ground water seepage into the pond. For most but not all of the elements, the main contribution to the total concentration is made by the suspended solids. Even when the residues are exposed, the total concentration of most elements is below 0.1 ppm, which is at or below regulatory limits. Exceptions include lead, iron, manganese, and nickel. During processing of the high grade pitchblende ores at the Mallinckrodt Chemical Works, the radium was precipitated as radium sulfate, along with lead sulfate (the ores contained about 6 percent lead) from a nitric acid dissolution of the ore. Barium was added to the solution from which the radium had been precipitated, causing precipitation of barium sulfate, which scavenged residual radium sulfate from the uranium solution. Uranium was then extracted using diethyl ether. The aqueous raffinate (waste stream) after uranium extraction contained the bulk of the thorium that precipitated. Thus, most of the 226Ra and 230Th in the residues is contained in insoluble sulfate salts. This does not mean, however, that all of the residues are sulfates, nor that the behavior of the radium and thorium in the residues would be those of the pure sulfate salts (Russell, 1994). The K-65 residues are present with two distinct types of materials. Approximately 73 percent is characterized as “slimes” (particle size less than 37 micrometers), and the remainder is sand. Most of the 226Ra is in the slimes fraction (U.S. Department of Energy, 1986, Table 3.6, p. 3-15). The 1986 FEIS assumes that the ground water system is isotropic and homogeneous and that the flow is uniform in one direction. This is known not to be true at the present time because of the pumping taking place at the contiguous sanitary land fill. Although there is no good information on the future duration of pumping, it will almost certainly not continue for periods that are long compared to the proposed site maintenance and monitoring period. Transport and concentrations of contaminants in the ground water were calculated by solving a mass transport equation that includes convective transport, molecular diffusion, hydraulic dispersion, chemical sorption, and radioactive decay. The mobility of the 226Ra and 230Th in the containment facility depends primarily on the movement of ground water through the facility. The chemical compounds of the radium and thorium in the residues may move either by dissolution to produce ions which are then transported by the ground water or as undissolved particulates which are carried by the ground water. If the radium and thorium are transported as dissolved ions, they are subject

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK to limitations on their rates of movement by their solubilities, the rate of ground water movement through the residues, and the sorption and desorption of radium and thorium on the medium through which they move. The latter phenomenon is a very important retardation mechanism and is dependent upon the distribution coefficients of the ions and the capacity of the medium. A distribution coefficient (Kd) of 100 cm3/g is assumed in the 1986 FEIS for radium in the clay sediments at both NFSS and Oak Ridge; this is considered to be a conservatively underestimated value. A value 10 times lower was assumed for the sandy soil at Hanford. If the radium and thorium are transported as undissolved particulates, they are subject to limitations on their rates and extent of movement by the relative sizes of the particulates and the pores through which they move (sieving action). If they behave as colloids they are subject to a type of transport mechanism entirely different from either of the two noted above. Colloids typically are considered to be charged solid particles of less than 10 micrometers effective diameter, and they may be either hydrophilic or hydrophobic, depending on whether they are surrounded with loosely-bound water molecules. In general, hydrophilic colloids are much more stable in aqueous media than hydrophobic colloids. Polymer-induced flocculation has been shown in laboratory batch studies to be very effective in agglomerating clay colloids. Colloidal clay species could carry contaminants sorbed on their surface; behavior of contaminants carried in this way would be very hard to predict (Nuttall and Long, 1993). For ground water contamination over times up to and including the period designated long-term in the 1986 FEIS (200 to 1,000 years) the radionuclide of greatest concern is 226Ra. Concentrations of 226Ra in ground water were modeled for thicknesses of clay in the interim cap corresponding to the conceptual cap designs discussed in Section 2 of the 1986 FEIS. Only clay was considered in the model because the layers of sand, gravel, etc. will not significantly inhibit water infiltration into the residues (U.S. Department of Energy, 1986, p. 4-62). The following is from the 1986 FEIS (U.S. Department of Energy, 1986, p. 4-63): In summary, the clay of the interim cap (Alternative 1) and the additional clay in the preferred long-term cap (Alternatives 2a and 2b) are expected to reduce (but not eliminate) water infiltration into the buried wastes and residues. The existing clayey soils beneath the containment area are expected to retard (but not eliminate) migration of radionuclides from the wastes and residues. Because the clay layers (including the so-called “gray clay” layer) are known to contain sand lenses, the average hydraulic properties of the underlying clayey materials are conservatively assumed to be between the properties of clay and sand. [The Committee notes that this is not conservative if the sand lenses are continuous through the clay for some distance beyond the waste facility, or if the distance between adjacent lenses is short.] Furthermore, over the long term, it is conservatively assumed that the properties of the

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK cutoff wall are the same as for the surrounding soils--i.e., that the cutoff wall offers no significant additional long-term barrier. Thus, the migration of contaminants may actually be slower than predicted in this analysis. In the extremely long term (times in excess of about 5,000 years), 230Th is the isotope of greatest concern because it provides a continuing supply of 226Ra. The distribution coefficient (Kd) values used in the retardation calculations are very important in assessing the potential health effects of storing the residues at NFSS. Good data are available on Kd values for thorium for site ground water conditions, including recent measurements made at the request of the Committee (Bechtel National, Inc., 1994a), that result in increased confidence that ionic thorium will be transported very slowly from the storage facility. However, the high charge on the thorium ion suggests the possibility of colloid formation, and the rate and mechanism of transport of colloids is extremely difficult to predict, but in general, colloids may be expected to follow the ground water movement. The proposed actions of replacing the interim cap with a “permanent” cap and of long-term site maintenance and monitoring do not address the potential risks to the public for periods of time commensurate with the duration of that risk. That is, the approximately 300-year period (or even a thousand years) covered by those actions is short compared to the half-life of 226Ra (1,600 years), and very short compared to the half-life of 230Th (75,400 years). The time-dependent characteristics of the residues at NFSS are basic to any discussion of the health and environmental issues associated with the site. In particular, the half lives of the sources of radiation are of paramount importance, as are their rates of movement. The radioactive isotopes 226Ra and 230Th are the primary sources of radiation at NFSS; 222Rn, a chemically inert gas, is a very important secondary source of radiation. The isotope 222Rn has a relatively short half life, and quickly establishes secular equilibrium with 226Ra, after which time it decays with the half life of 226Ra. The isotope 226Ra is the daughter of 230Th, but because 230Th has such a long half life, it takes a long time to reach secular equilibrium. However, in only 1,585 years the 226Ra reaches 50 percent of its original amounts, during which time the amount of 230Th decreases only about 1.5 percent. All three radioisotopes are energetic alpha particle emitters. Table 5 gives the half lives of the isotopes of major interest at NFSS. From the values in the table it is apparent that over short time periods the principal radiation sources are 226Ra and 222Rn. However, over very long times 230Th becomes the primary source of radiation because it is a continuing source of the 226Ra and 222Rn daughters. Therefore, it is important to consider the behavior of the 230Th, parent of 226Ra, as well as 226Ra itself. (There are ten radioisotopes in the 230Th decay chain, some of which are very energetic gamma emitters. The very short half lives of these radioisotopes ensure that theyare all in secular equilibrium with the parent 226Ra, and thus that they are major contributors to the dose attendant with 226Ra.)

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK TABLE 5. Half-Lives of Principal NFSS Radioisotopes 230Th 75,400 years 226Ra 1,600 years 222Rn (in secular equilibrium with 226Ra) 3.8235 days

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK The residues are assigned different classifications based on the U3O8 content of the originating ore (U.S. Department of Energy, 1986, Table 3.5, p. 3-14). Those classified as K-65 have approximately 88 percent of the total 226Ra in the residues. Those classified as L-30 contain about 10 percent of the total 226Ra in the residues and were derived from ores containing about 10 percent U3O8, and those classified as L-50 were derived from ores containing about 7 percent U3O8. Of the total approximately 11,000 cubic meters of residues, the K-65 residues comprise 28 percent, and the L-30 residues comprise 55 percent. In addition to the radioisotopes, there are substantial concentrations of non-radioactive elements in the residues. For example, of the total K-65 residues, 3 percent is barium, 5.6 percent is lead, and 1 percent is molybdenum. Although the concentrations of these and other elements differ somewhat among the several residues, they are similar in all the residues (U.S. Department of Energy, 1986, Table 3.7, p. 3-17). The interim cap at NFSS was designed to “ensure that the rate of radon emanation from the buried contaminated waste is negligible (far below the allowable limit).” Maintenance of the containment facility over a 25- to 50-year service life is expected to repair any damage from erosion, settling, frost heaving, cracking, or biotic intrusion (Bechtel National, Inc., 1986a, p. 44). A radon diffusion coefficient of 0.00016 cm2/sec was used for calculating 222Rn releases from damp clay and damp residues and wastes (25 percent moisture) at NFSS and Oak Ridge. A diffusion coefficient of 0.0036 cm2/sec was used for calculating releases from drier (13 percent moisture) NFSS wastes and residues at Hanford and topsoil and stony soils at NFSS and Oak Ridge. This dependence of diffusion coefficient on moisture content is cited as the reason for the significant difference between radon releases at the Hanford site and the Oak Ridge site. The interim cap consists of (among other things) a 0.5 m layer of soil, underlain by 0.9 m layer of clay. The radon flux through the interim cap surface, exclusive of naturally occurring radon, was calculated to be 0.061 pCi/m2/sec. The radon flux from natural sources in the topsoil was stated to be 0.24 pCi/m2/sec (Bechtel National, Inc., 1986a, p. 44). The combined flux of 0.301 pCi/m2/sec would be well below the DOE and EPA limit of 20 pCi/m2/sec. Volatile organic compounds (VOCs) are not a particular problem at NFSS. The amount of organic wastes on the site is relatively small. Organic compounds were not produced or used in handling or moving the residues at NFSS, and there do not appear to be significant amounts of such materials on site from previous uses of the site. This particulates-to-air pathway for contaminant exposure is most likely to occur when the residues are exhumed, treated, and packaged for shipment, and are reburied. Exposure from particulates is also likely during a transportation accident if the shipping package is breached.

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK There is little explicit discussion of perched water in random sand lenses in the brown clay in the 1986 FEIS. It is, however, likely that there is perched water at the NFSS site. Its impact, if any, on the site analysis is not clear. An important alternative, that of solidifying the high-level residues on site and shipping the solidified residues to an off-site location, has not been considered, even though this alternative was chosen for managing essentially identical residues of common origin currently stored in silos at the Fernald Environmental Management Project (FEMP) site in Ohio. If this alternative is considered, the occupational as well as public health and safety aspects are important. Inputs from waste treatment technology projects, such as the project for handling similar residues now being implemented at the FEMP site, will provide important information for making such assessments. Of the alternatives considered for managing the K-65 residues at NFSS, the one adopted as most desirable at the FEMP site was not considered at NFSS. That alternative is treatment of the residues and then shipment of them off-site. Although the situations are different at the two sites, the treat and then ship off-site alternative is worth considering at the NFSS because of the permanent removal of the residues from NFSS achieved thereby, and because the residues can in principle be fixed in a form safe both for shipment and final disposal. Admittedly, the residue storage situation at the FEMP site is not the same as the situation at NFSS, and may in some respects be simpler for treating the residues than the situation at NFSS. The FEMP residues are still in silos from which they can be recovered by hydraulic mining before treating, whereas the NFSS residues must be exhumed from the storage facility in which they are buried before they can be treated. However, the exhumation operations have been examined in the 1986 FEIS for Alternative 2b. The costs of the treating and shipping operations at the two sites are considered below under Conclusion 7. The present and potential future interactions between the NFSS and disposal sites adjacent to the NFSS, where non-radioactive toxic chemical and landfill wastes are currently disposed, have not been addressed adequately, either in the NFSS final environmental impact statement (FEIS) or in subsequent studies and documentation. The NFSS is bounded on two sides by major waste disposal facilities, the Chemical Wastes Management (CWM) Chemical Services, Inc., to the north and Modern Landfill, Inc., to the east. Current site plans and ongoing monitoring do not address the present or long-term potential impacts of these sites on the waste storage at NFSS. This is particularly important given the time frame (perpetual care), hydrological uncertainty, and the potential public health impacts of the wastes at these sites. The Committee found no evidence that these sites are impacting the waste at NFSS at the present time. However, there is currently no routine testing done to monitor pollutant migration which may impact the NFSS site, and

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK little information is available on the current or long-term health risks posed by these neighboring sites. The CWM site, parts of which have been used for waste disposal since 1942, is currently the subject of a Resource Conservation and Recovery Act (RCRA) corrective action to remediate and confine extensive chemical contamination of the ground water. Off-site migration of these chemical contaminants could impact the waste containment at NFSS. As part of the RCRA corrective action, a site risk assessment will be conducted. The results of the CWM risk assessment and other site investigations may have important implications for the management of the wastes at NFSS. No information was available to the Committee concerning the long-term plans for closure of the neighboring facilities. The cessation of current pumping activities at these sites will undoubtedly impact area ground water dynamics. In addition, the long-term integrity of waste containment at these sites (300 to 1000 years) is unknown. The Committee found no analysis of the long-term public health impacts of the neighboring facilities in the regulatory files. Under RCRA, risk assessments are conducted only for a period ending 70 years after facility closure. The scenario that has been analyzed for NFSS - erosion of the cap over hundreds of years followed by construction of a residence on the disposal the site - is equally likely at CWM and Modern Landfill, Inc. Indeed, these facilities have much larger surface areas than NFSS. Because the neighboring facilities contain long-lived toxic materials such as lead, arsenic, and polychlorinated biphenyls, this scenario might well have unacceptable consequences. The Committee notes the possible inconsistency in removing the residues at NFSS without analyzing toxic material behavior in the same scenario. This reflects a social decision that radioactive wastes are to be handled with a longer time horizon than chemical wastes. In the present situation we have not judged whether this differentiation is appropriate. The potential future health hazards posed by non-radiological, toxic materials such as lead and barium that are constituents of the buried high-level residues at NFSS have not been adequately assessed. The NFSS residues and wastes contain chemical elements and compounds that potentially could contaminate the environment. Selected concentrations of non-radioactive elements in the residues and organic compounds in the wastes are given in Table B-12 and Table B-13 (Appendix B). Given the nature of these materials, additional analyses of their behaviors and potential health effects is required. This analysis should be consistent with full recognition of the unpredictability of human behavior over thousands of years into the future. The K-65 residues contain a high concentration of lead - 56,000 ppm, or almost 6 percent. Environmental monitoring results for this site, particularly ground water tests, do not routinely report lead concentrations. Therefore it is not possible to assess the adequacy of current containment or trace the long-term migration of these contaminants through the

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK environment. Furthermore, it is by no means certain that the principal exposure pathway for lead would be via ground water. The K-65 residues also contain barium, cobalt, nickel and copper, rare earth elements, palladium, and molybdenum. Although no organic chemicals are reported in the residues, they may exist in the NFSS wastes. Past activities at the site are reported to have included manufacture of trinitrotoluene, storage of chemical warfare substances and ammunition, boron isotope separation, and research, production, and burning of high energy fuels (Golder Associates, 1993). Limited monitoring suggests the presence of some organic solvents (U.S. Department of Energy Oak Ridge Operations, 1992). More complete analysis is necessary to evaluate potential risks. Periodic chemical analysis of environmental samples for the full range of EPA priority pollutants would be appropriate to evaluate potential chemical risks. This would also identify the presence of compounds, such as organic solvents, which might affect the mobility of the residues. There are substantial uncertainties in the estimates of costs and associated risks for managing the residues at NFSS that have not been fully addressed. In the 1986 FEIS, installation of the permanent cap with present residues and waste configuration was estimated to cost $4.2 million (Alternative 2a); if all the residues were excavated, treated, solidified, and returned to the WCS, followed by permanent cap installation, the cost was estimated to rise to $14.4 million (Alternative 2b). If, on the other hand, all wastes were retained at the NFSS but all the residues were excavated and shipped to Hanford (Alternative 4a) or to Oak Ridge (Alternative 4c) for storage, the estimated Action Period costs were $27 million and $17 million, respectively - the differences are attributable to transportation and disposal costs. The total volume of the residues being shipped to Hanford or Oak Ridge would be 11,000 m3. For all alternatives in the 1986 FEIS involving excavation of residues, the expected number of adverse effects (fatal cancers plus genetic defects) from exposure to radiation range from 0.10 to 0.24. The estimated number of transportation-related deaths and injuries for these alternatives were much higher, ranging from 0.11 to 3.9 deaths and 0.19 to 66 injuries (U.S. Department of Energy, 1986, p. 4-96, Table 4.61). The Committee reviewed these estimates, along with two more recent estimates involving removal of only the K-65 residues from the NFSS (letter of September 2, 1994, from R.E. Kirk, DOE Oak Ridge National Laboratory, to R.S. Andrews). Both new estimates are based on the excavation and removal of 2,450 m3 (3,210 yd3), 82 percent of the 3,000 m3 (3,925 yd3) of K-65 residues at NFSS. One of these estimated alternatives treatments involves placing the K-65 residues into steel drums, then into containers, and shipping the filled containers to a facility at Yucca Mountain, NV, at an estimated cost of about $85 million. The second involves treatment of the K-65 residues at the NFSS and subsequent shipment of the processed residues to a National Laboratory for disposal, at a total cost of $30 million. The type of treatment is not specified, nor the form of the treated

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SAFETY OF THE HIGH-LEVEL URANIUM ORE RESIDUES AT THE NIAGARA FALLS STORAGE SITE, LEWISTON, NEW YORK material. The L-30, F-32 and L-50 residues would remain at the NFSS. No risk estimates have been provided for these alternatives. The older cost estimates are not directly comparable to the newer ones. The newer set is preliminary and is presented in terms of 1994 dollars, rather than the 1982 dollars used in the 1986 FEIS. Nevertheless, the $85 and $30 million estimates of K-65 residue removal in this set are substantially higher than the similar estimates of $27 and $17 million given in the 1986 FEIS for removal of all the residues and their disposal at Hanford or Oak Ridge, respectively. Comparable estimates of costs and associated risks to workers and the public for the removal, treatment, and disposal of the K-65 residues at the FEMP site, comprising 6,120 m3, are not yet available. When such estimates, along with new data and monitoring results, become available, assuming that the wastes are kept on-site at the NFSS and that all the high-level residues are treated and shipped off-site, other, more desirable alternatives for long-term disposal of NFSS residues may have emerged. Further, the Committee sees little technical reason for using different waste management practices for the FEMP residues and the NFSS residues based on “defense” versus “non-defense” designations, respectively. Current site monitoring activities are inadequate for the determination of long-term site integrity and potential future risks to the public and the environment from the movement off site of radioactive and non-radioactive wastes in the NFSS containment structure, as well as the possible influx of waste materials from the disposal sites adjacent to the NFSS. Of the 43 ground water sampling locations at the NFSS, 13 are located at the perimeter of the Wastes Containment Structure (WCS) and 28 are on-site but outside the WCS. In 1993 and 1994, only 9 locations were sampled for total uranium content and only 11 sampled for 226Ra. Reductions in sampling frequency were based on a lack of previous monitored values above background levels and the expectation that 226Ra would not migrate beyond the perimeter of the WCS until the 5,000-to 10,000-year time frame. No attempt was made to monitor toxic, non-radioactive materials such as lead. Even after the high-level residues have been removed from the site, continued monitoring and maintenance will probably be necessary because of the close proximity of residences and public facilities. Installation of a permanent cap would result in the loss of the 13 WCS-perimeter sampling locations, resulting in long migration distances for materials moving in the ground water before detection. Moreover, in the 1986 FEIS, DOE has indicated that monitoring efforts would cease after 200 years unless DOE assumes perpetual care of the residues and wastes at the NFSS.