[en] The objective of this technical note is to characterize seismic ground motion at the Savannah River Site (SRS) by postulated earthquakes that may impact facilities at the site. This task is accomplished by reviewing the deterministic and probabilistic assessments of the seismic hazard to establish the earthquakes that control the hazard to establish the earthquakes that control the hazard at the site and then evaluate the associated seismic ground motions in terms of response spectra. For engineering design criteria of earthquake-resistant structures, response spectra serve the function of characterizing ground motions as a function of period or frequency. These motions then provide the input parameters that are used in the analysis of structural response. Because they use the maximum response, the response spectra are an inherently conservative design tool. Response spectra are described in terms of amplitude, duration, and frequency content, and these are related to source parameters, travel path, and site conditions. Studies by a number of investigators have shown by statistical analysis that for different magnitudes the response spectrum values are different for differing periods. These facts support Jennings' position that using different shapes of design spectra for earthquakes of different magnitudes and travel paths is a better practice than employing a single, general-purpose shape. All seismic ground motion characterization results indicate that the PGA is controlled by a local event with M_w < 6 and R < 30km. The results also show that lower frequencies are controlled by a larger, more distant event, typically the Charleston source. The PGA of 0.2 g, based originally on the Blume study, is consistent with LLNL report UCRL-15910 (1990) and with the DOE position on LLNL/EPRI

[en] Groundwater transport of contaminants from the F-Area seepage basin at the Savannah River Plant (SRP) was calculated using a three-dimensional, second-order moment technique. The numerical method calculates the zero, first, and second moment distributions of concentration within a cell volume. By summing the moments over the entire solution domain, and using a Lagrangian advection scheme, concentrations are transported without numerical dispersion errors. Velocities obtained from field tests are extrapolated and interpolated to all nodal points; a variational analysis is performed over the three-dimensional velocity field to ensure mass consistency. Transport predictions are calculated out to 12,000 days. 28 refs., 9 figs

[en] The damage to underground facilities caused by earthquakes was evaluated in order to determine potential seismic risk to an underground nuclear waste repository. Earthquake effects were delineated in terms of both displacements and accelerations. For underground facilities, displacements are considered more damaging than accelerations. An evaluation of the data was made in terms of acceleration, velocity, and displacement as a function of earthquake magnitude, distance, and depth. Damage decreases with distance from the source and with depth below the ground surface. However, extensive damage can occur if the facility is cut by a fault or fault fissure along which a slip can occur during an earthquake. Peak acceleration decreases with depth; however, peak displacements show much less reduction with depth

[en] In support of the Savannah River Technology Center (SRTC) effort to develop K-Reactor seismic design basis ground motions, SRTC monitored local high-explosive tests at a ''free-field'' site adjacent to K-Reactor and on the -40 level on the foundation of K-Reactor. The high-explosive tests were part of the SRTC/United States Geological Survey (USGS) regional refraction and attenuation experiment that used deeply buried high explosive charges near New Ellenton, Snelling, and at more distant South Carolina sites. The primary purpose of the Reactor measurements are to compare the relative amplitude and frequency content of ambient noise and shot generated ground motions measured at the K-Reactor foundation level and in the ''free-field'' so that foundation effects to ground motions can be documented and possibly incorporated in the facility design basis. Data analysis indicates that one of the five high explosive tests provided sufficient excitations at K-Reactor to produce satisfactory signal-to-noise between about 1 Hz and 15 Hz. Within this frequency band, Fourier spectral amplitude ratios of motions recorded within the first 10 seconds of first motion show substantial reductions (30 endash 50%) on shot radial and transverse components for frequencies greater than about 3 to 5 Hz. Approximately 50% reductions between 10 to 15 Hz were seen on vertical component ratios, and amplifications of 100% at 4 Hz and 5 Hz endash 6 Hz

[en] The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository

[en] Forty-eight locations were identified that received a variety of radioactive and nonradioactive constituents during the past 35 years including surface impoundments and shallow land burial facilities. Detailed environmental assessments of existing waste disposal areas, as well as new waste disposal techniques and disposition of tritiated water, were completed to air in an evaluation of the low level, mixed and hazardous waste management activities. These assessments result in estimation of risk, or residual risk, posed by each disposal area to various receptors as a function of waste management alternative. For example, at existing waste sites, the closure actions evaluated were waste removal and closure, no waste removal and closure, and no action; several pathways/receptors were considered, including groundwater to river, groundwater to well, atmospheric transport, occupational exposure, direct exposure, and contamination followed by ingestion of crops and meat. Modeling of chemical transport in a variety of media was an integral part of the assessment process. The quality of the models used and the application of these models were assured by an explicit quality assurance program

[en] The regional scale model, calibrated by an automatic least-squares procedure, resulted in a set of hydraulic parameter values consistent with other methods. The automatic procedure facilitated the calibration of the model in which ten hydraulic parameters were treated as unknowns. Ground water flow velocities were used to perform particle-tracking analyses. Local scale transport models were developed for the F and H Area seepage basins. The grid refinement technique in conjunction with the parameter estimation method was very effective in the analysis of regional and local flow and transport phenomena. The estimated hydraulic parameters, determined objectively by the automatic procedure, showed excellent agreement with results from other methods. The local scale transport modeling required significant mesh refinements to meet the objectives of the study. Thus, it was necessary to reduce the area of the model domain to maintain cost and computational efficiency. Regional flow phenomena were preserved in the reduced scale models by extracting hydraulic boundaries and parameters from the regional flow model

[en] Modeling of transport in the environmental media was performed. Predicting the future performance of any waste site or facility and postulated actions in terms of migration of potential hazardous materials requires mathematical models capable of simulating flow and transport in the groundwater. Three-dimensional groundwater flow and transport models were developed to simulate the groundwater movement and contaminant transport in the Raw Materials Fabrication Area and the Separations Area. The overall objective of the analysis was to develop groundwater flow models that quantifies the rate and direction of the groundwater movement from the waste sites to points of discharge. The USGS Modular 3D model uses the strongly implicit procedure to solve sets of simultaneous finite-difference equations that represent the groundwater flow process. The transport functions, which are the concentration or mass flux at time t due to continuous injection starting at time t', were obtained by solving the three-dimensional advection-dispersion equations using the Sandia Waste Isolation Flow and Transport (SWIFT) model. 5 refs., 7 figs., 2 tabs

[en] Previously acceptable waste management practices (e.g., the use of unlined seepage basins) for discarding of wastes from nuclear materials production has resulted in occasional cases of groundwater contamination beneath some disposal sites, mainly in water-table aquifers. Groundwater contaminants include volatile organic compounds, heavy metals, radionuclides, and other chemicals. The closure of active and inactive waste sites that have received hazardous and/or low-level radioactive materials at the Savannah River Plant (SRP) is planned as part of an overall program to protect groundwater quality. DOE developed and submitted to Congress a groundwater protection plan for SRP. This initial plan and subsequent revisions provide the basis for closure of SRP waste sites to comply with applicable groundwater protection requirements. An environmental analysis of the closure options for the criteria waste sites that have received hazardous and/or low-level radioactive wastes was conducted to provide technical support. The several parts of this environmental analysis include description of geohydrologic conditions; determination of waste inventories; definition of closure options; modeling of environmental pathways; assessment of risk; and analysis of project costs. Each of these components of the overall analysis is described in turn in the following paragraphs. Production operations at SRP have generated a variety of solid, hazardous, and low-level radioactive waste materials. Several locations onplant have been used as waste disposal sites for solid and liquid wastes. Seventy-six individual waste sites at 45 distinct geographical locations on SRP have received hazardous, low-level radioactive, or mixed wastes. These waste sites can be categorized into 26 groupings according to the function of the waste disposed. 15 refs., 6 figs., 5 tabs

[en] A risk assessment strategy that is cost effective and minimized human health risks was developed for closure of hazardous waste sites at the Savannah River Plant. The strategy consists of (1) site characterization, (2) contaminant transport modeling, and (3) determination of relative merits of alternative remedial actions according to the degree of health protection they provide