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GROUND-WATER CONTRIBUTION TO DOSE FROM PAST HANFORD OPERATIONS

Description: The Hanford Environmental Dose Reconstruction (HEOR) Project is being conducted to estimate radiation doses that populations and individuals could have received from Hanford Site operations from 1944 to the present. Four possible pathways by which radionuclides originating in ground water on the Hanford Site could have reached the public have been identified: 1) through contaminated ground water migrating to the Columbia River; 2) through wells on or adjacent to the Hanford Site; 3) through wells that draw some or all of their water from the Columbia River (riparian wells); and 4) through atmospheric deposition resulting in the contamination of a small watershed that, in turn, results in contamination of a shallow well or spring. These four pathways make up the "ground-water pathway ," which is the subject of this study. The objective of the study was to assess the extent to which the groundwater pathway contributed to radiation doses that populations or individuals may have received from past operations at Hanford. The assessment presented in this report was performed by 1) reviewing the extensive ´┐Żliterature on ground water and ground-water monitoring at Hanford and 2) performing simple calculations to estimate radionuclide concentrations in ground water and the Columbia River resulting from ground-water discharge. Radiation doses that would result from exposure to this ground water and surface water were calculated. The study conclusion is that the ground-water pathways did not contribute significantly to dose. Compared with background radiation in the TriCities {300 mrem/yr), estimated doses are small: 0.02 mrem/yr effective dose equivalent from discharge of contaminated ground water to the Columbia River; 1 mrem/yr effective dose equivalent from Hanford Site wells; 11 mrem/yr effective dose equivalent from riparian wells; and 1 mrem/yr effective dose equivalent from the watershed. Because the estimated doses are so small, the recommendation is that further work ...
Date: January 1, 1992
Creator: Freshley, M. D. & Thorne, P. D.
Partner: UNT Libraries Government Documents Department

Sensitivity and uncertainty analyses of unsaturated flow travel time in the CHnz unit of Yucca Mountain, Nevada

Description: This report documents the results of sensitivity and uncertainty analyses conducted to improve understanding of unsaturated zone ground-water travel time distribution at Yucca Mountain, Nevada. The US Department of Energy (DOE) is currently performing detailed studies at Yucca Mountain to determine its suitability as a host for a geologic repository for the containment of high-level nuclear wastes. As part of these studies, DOE is conducting a series of Performance Assessment Calculational Exercises, referred to as the PACE problems. The work documented in this report represents a part of the PACE-90 problems that addresses the effects of natural barriers of the site that will stop or impede the long-term movement of radionuclides from the potential repository to the accessible environment. In particular, analyses described in this report were designed to investigate the sensitivity of the ground-water travel time distribution to different input parameters and the impact of uncertainty associated with those input parameters. Five input parameters were investigated in this study: recharge rate, saturated hydraulic conductivity, matrix porosity, and two curve-fitting parameters used for the van Genuchten relations to quantify the unsaturated moisture-retention and hydraulic characteristics of the matrix. 23 refs., 20 figs., 10 tabs.
Date: October 1, 1991
Creator: Nichols, W.E. & Freshley, M.D.
Partner: UNT Libraries Government Documents Department

High Burnup Effects Program A State-of-the-Technology Assessment

Description: Various analytical models and empirical correlations describing the fission gas release phenomenon were examined. An evaluation was made of the current pertinent experimental data on the subject of high burnup fission gas release. Data reported by individual investigators were compared and evaluated in relation to their applicability to the content and scope of the High Burnup Effects Program. These evaluations then form the bases for defining the data needs, and the selection of variables to be studied in this program.
Date: June 1, 1982
Creator: Rising, K. H.; Bradley, E. R.; Williford, R. E. & Freshley, M D.
Partner: UNT Libraries Government Documents Department

Assessment of hydrologic impact of extending exploratory shafts into the Calico Hills nonwelded tuff unit at Yucca Mountain, Nevada

Description: The US Department of Energy (DOE) is performing analyses to address an objection by the US Nuclear Regulatory Commission to plans in the Consultation Draft of the Site Characterization Plan for direct excavation of the Calico Hills nonwelded (CHn) unit within the repository exploration block at Yucca Mountain, Nevada. The excavation was planned as part of site characterization activities for the potential high-level nuclear waste repository at Yucca Mountain. This characterization activities for the potential high-level nuclear waste repository at Yucca Mountain. This characterization activity has been deferred, pending the results of a risk/benefit analysis of alternative methods for obtaining needed characterization data from CHn unit. The benefits from characterizing the CHn unit are generally related to obtaining information leading to improved confidence in predictions of site performance. The risks are generally associated with potential adverse impacts to site performance that result from excavation or other intrusion into the CHn unit. The purpose of the risk/benefit analysis is to produce a recommendation to the Director, Regulatory and Site Evaluation Division. DOE/Yucca Mountain Site Characterization Project Office for a strategy for characterizing the CHn unit. The recommendation will describe characterization activities that are expected to provide the needed information while limiting adverse impacts to site performance to the extent practical. The risk/benefit analysis was supported with scoping calculations to provide a quantitative evaluation of the impacts associated with different strategies. The working group responsible for the risk/benefit analysis requested that these scoping calculations to be supported with more detailed performance assessments for evaluating impacts of different characterization activities. This report summarizes the results of these performance assessment analyses. 9 refs., 30 figs., 1 tab.
Date: March 1, 1991
Creator: Nichols, W.E.; Freshley, M.D. & Rockhold, M.L.
Partner: UNT Libraries Government Documents Department

Simulation of two-phase carbon-14 transport at Yucca Mountain, Nevada

Description: In support of pacific Northwest Laboratory`s (PNL) preliminary total system performance assessment of the proposed high-level nuclear-waste repository at Yucca Mountain, transport of carbon-14 (C{sup 14}) in the unsaturated zone was numerically modeled with the Multiphase Subsurface Transport Simulator (MSTS). Total system performance assessments are being conducted to estimate potential cumulative releases and doses from radionuclides being transported through different pathways to the accessible environment from the proposed waste repository. Transport of radionuclides in the gaseous and liquid phases are pathways through which some of the inventory in the proposed repository could reach the accessible environment. Carbon-14 transport in the unsaturated zone at Yucca Mountain was estimated with MSTS by considering two-phase diffusion, advection, phase petitioning, and radioactive decay.Transport results were based on a two-dimensional physical and hydrogeological system that represented an east-west cross section through Yucca Mountain. Carbon-14 source rates from failed repository waste canisters were estimated from the source term modeling subtasks associated with PNL`s total system performance assessment of the proposed Yucca Mountain repository. Simulation results included estimates of liquid, gas, heat, and C{sup 14} transport within the unsaturated zone at Yucca Mountain. Predictions of C{sup 14} distributions surrounding the proposed nuclear waste repository within Yucca Mountain and a brief description of the thermal-hydrogeologic computer code MSTS are presented.
Date: February 1, 1992
Creator: White, M.D.; Freshley, M.D. & Eslinger, P.W.
Partner: UNT Libraries Government Documents Department

Experiment operations plan for the TH-2 experiment in the NRU reactor. [PWR; BWR]

Description: A series of thermal-hydraulic and cladding materials deformation experiments were conducted using light-water reactor fuel bundles as part of the Pacific Northwest Laboratory Loss-of-Coolant Accident (LOCA) Simulation Program. This report is the formal operations plan for TH-2--the second experiment in the series of thermal-hydraulic tests conducted in the National Research Universal (NRU) reactor, Chalk River, Ontario, Canada. The major objective of TH-2 was to develop the experiment reflood control parameters and the procedures to be used in subsequent experiments in this program. In this experiment, the data acquisition and control system was used to control the fuel cladding temperature during a simulated LOCA by using variable reflood coolant flow.
Date: June 1, 1983
Creator: Russcher, G.E.; Wilson, C.L.; Parchen, L.J. & Freshley, M.D.
Partner: UNT Libraries Government Documents Department

Development of annular-coated-pressurized and sphere-pac LWR fuels

Description: Annular-coated (graphite)-pressurized and sphere-pac fuel rod designs, which are expected to exhibit improved PCI-failure resistance, and, thus, more reliable extended burnup performance, are being developed. Data sufficient to provide the technical bases needed to license lead test assemblies of the improved designs for irradiation in commercial LWRs are being obtained. Out-of-reactor experiments, in-reactor instrumented experiments, in-reactor power-ramp tests, and lead-rod demonstration irradiations are providing the needed data to support the technical bases. Results obtained to-date confirm the expected performance improvement compared with a solid-pellet reference design. The degree of improvement with respect to PCI-resistance remains to be quantified during forthcoming power-ramp tests on fuel rod segments irradiated to moderate burnup levels in a commercial LWR.
Date: December 1, 1981
Creator: Buckman, F. W.; Crouthamel, C. E.; Freshley, M. D. & Barner, J. O.
Partner: UNT Libraries Government Documents Department

High Burnup Effects Program

Description: This is the final report of the High Burnup Effects Program (HBEP). It has been prepared to present a summary, with conclusions, of the HBEP. The HBEP was an international, group-sponsored research program managed by Battelle, Pacific Northwest Laboratories (BNW). The principal objective of the HBEP was to obtain well-characterized data related to fission gas release (FGR) for light water reactor (LWR) fuel irradiated to high burnup levels. The HBEP was organized into three tasks as follows: Task 1 -- high burnup effects evaluations; Task 2 -- fission gas sampling; and Task 3 -- parameter effects study. During the course of the HBEP, a program that extended over 10 years, 82 fuel rods from a variety of sources were characterized, irradiated, and then examined in detail after irradiation. The study of fission gas release at high burnup levels was the principal objective of the program and it may be concluded that no significant enhancement of fission gas release at high burnup levels was observed for the examined rods. The rim effect, an as yet unquantified contributor to athermal fission gas release, was concluded to be the one truly high-burnup effect. Though burnup enhancement of fission gas release was observed to be low, a full understanding of the rim region and rim effect has not yet emerged and this may be a potential area of further research. 25 refs., 23 figs., 4 tabs.
Date: April 1, 1990
Creator: Barner, J. O.; Cunningham, M. E.; Freshley, M. D. & Lanning, D. D.
Partner: UNT Libraries Government Documents Department

Development of a three-dimensional ground-water model of the Hanford Site unconfined aquifer system: FY 1995 status report

Description: A three-dimensional numerical model of ground-water flow was developed for the uppermost unconfined aquifer at the Hanford Site in south-central Washington. Development of the model is supported by the Hanford Site Ground-Water Surveillance Project, managed by the Pacific Northwest National Laboratory, which is responsible for monitoring the sitewide movement of contaminants in ground water beneath the Hanford Site. Two objectives of the Ground-Water Surveillance Project are to (1) identify and quantify existing, emerging, or potential ground-water quality problems, and (2) assess the potential for contaminants to migrate from the Hanford Site through the ground-water pathway. Numerical models of the ground-water flow system are important tools for estimating future aquifer conditions and predicting the movement of contaminants through ground water. The Ground-Water Surveillance Project has supported development and maintenance of a two-dimensional model of the unconfined aquifer. This report describes upgrade of the two-dimensional model to a three-dimensional model. The numerical model is based on a three-dimensional conceptual model that will be continually refined and updated as additional information becomes available. This report presents a description of the three-dimensional conceptual model of ground-water flow in the unconfined aquifer system and then discusses the cur-rent state of the three-dimensional numerical model.
Date: December 1, 1995
Creator: Wurstner, S.K.; Thorne, P.D.; Chamness, M.A.; Freshley, M.D. & Williams, M.D.
Partner: UNT Libraries Government Documents Department

Single-shell tank constituent rankings for use in preparing waste characterization plans

Description: Waste characterization efforts for underground single-shell tanks (SSTs) containing chemical and radioactive mixed wastes at the US Department of Energy's (DOE) Hanford Site are currently under way. As a component of this effort, an analysis was conducted to give a preliminary ranking of possible constituents in the SST waste and provide data for establishing detection limit requirements for the SST characterization effort. These SST constituent rankings were based on a relative comparison using potential human health impacts modeled using a hypothetical exposure scenario. This modeling effort used preliminary estimates of the SST inventories, simplified estimates of constituent release rates and environmental transport, a hypothetical usage location, and a standard Hanford exposure scenario. The results of this evaluation are SST constitutents for each of six groups of SSTs ranked according to their relative potential for impacts. The relative rankings for different recharge rates at the tank farms were nearly equivalent. Sensitivity tests demonstrated that the rankings are influenced by changes in recharge and transport parameters. 45 refs., 18 figs., 2 tabs.
Date: June 1, 1991
Creator: Droppo, J.G. Jr.; Buck, J.W.; Wilbur, J.S.; Strenge, D.L. & Freshley, M.D.
Partner: UNT Libraries Government Documents Department

Tritium monitoring in groundwater and evaluation of model predictions for the Hanford Site 200 Area Effluent Treatment Facility

Description: The Effluent Treatment Facility (ETF) disposal site, also known as the State-Approved Land Disposal Site (SALDS), receives treated effluent containing tritium, which is allowed to infiltrate through the soil column to the water table. Tritium was first detected in groundwater monitoring wells around the facility in July 1996. The SALDS groundwater monitoring plan requires revision of a predictive groundwater model and reevaluation of the monitoring well network one year from the first detection of tritium in groundwater. This document is written primarily to satisfy these requirements and to report on analytical results for tritium in the SALDS groundwater monitoring network through April 1997. The document also recommends an approach to continued groundwater monitoring for tritium at the SALDS. Comparison of numerical groundwater models applied over the last several years indicate that earlier predictions, which show tritium from the SALDS approaching the Columbia River, were too simplified or overly robust in source assumptions. The most recent modeling indicates that concentrations of tritium above 500 pCi/L will extend, at most, no further than {approximately}1.5 km from the facility, using the most reasonable projections of ETF operation. This extent encompasses only the wells in the current SALDS tritium-tracking network.
Date: August 1, 1997
Creator: Barnett, D.B.; Bergeron, M.P.; Cole, C.R.; Freshley, M.D. & Wurstner, S.K.
Partner: UNT Libraries Government Documents Department

The predicted impacts to the groundwater and Columbia River from ammoniated water discharges to the 216-A-36B crib

Description: Impact from past and potential future discharges of ammoniated water to the 216-A-36B crib have on groundwater and river concentrations of hazardous chemical constitutents are studied. Until August 1987, the 216-A-36B crib, located in the 200-East Area of the Hanford Site, accepted ammoniated water discharges. Although this study addresses known hazardous chemical constituents associated with such discharges, the primary concern is the discharge of NH/sub 4/OH because of its microbiological conversion to NO/sub 2//sup /minus// and NO/sub 3//sup /minus//. As a result of fuel decladding operations, material balance calculations indicate that NH/sub 4/OH has been discharged to the 216-A-36B crib in amounts that exceed reportable quantities under the Comprehensive Environmental Response, Compensation and Liability Act of 1980. Although flow to the crib is relatively constant, the estimated NH/sub 4/OH discharge varies from negligible to a maximum of 10,000 g-molesh. Because these discharges are intermittent, the concentration delivered to the groundwater is a function of soil sorption, microbiological conversion rates of NH/sub 4//sup +/ to NO/sub 2//sup /minus// and NO/sub 3//sup /minus//, and groundwater dispersion. This report provides results based on the assumptions of maximum, nominal, and discountinued NH/sub 4/OH discharges to the crib. Consequently, the results show maximum and realistic estimates of NH/sub 4//sup +/, NO/sub 2//sup /minus// and NO/sub 3//sup /minus// concentrations in the groundwater.
Date: March 1, 1988
Creator: Buelt, J.L.; Conbere, W.; Freshley, M.D.; Hicks, R.J.; Kuhn, W.L.; Lamar, D.A. et al.
Partner: UNT Libraries Government Documents Department

Experiment operations plan for the MT-4 experiment in the NRU reactor. [PWR]

Description: A series of thermal-hydraulic and cladding materials deformation experiments were conducted using light-water reactor fuel bundles as part of the Pacific Northwest Laboratory Loss-of-Coolant Accident (LOCA) Simulation Program. This report is the formal operations plan for MT-4 - the fourth materials deformation experiment conducted in the National Research Universal (NRU) reactor, Chalk River, Ontario, Canada. A major objective of MT-4 was to simulate a pressurized water reactor LOCA that could induce fuel rod cladding deformation and rupture due to a short-term adiabatic transient and a peak fuel cladding temperature of 1200K (1700/sup 0/F).
Date: June 1, 1983
Creator: Russcher, G.E.; Wilson, C.L.; Parchen, L.J.; Marshall, R.K.; Hesson, G.M.; Webb, B.J. et al.
Partner: UNT Libraries Government Documents Department

LOCA simulation in NRU program: data report for the fourth materials experiment (MT-4)

Description: A series of in-reactor experiments were conducted using full-length 32-rod pressurized water reactor (PWR) fuel bundles as part of the Loss-of-Coolant Accident (LOCA) Simulation Program by Pacific Northwest Laboratory (PNL). This experiment (MT-4) was funded by the US Nuclear Regulatory Commission (NRC) to evaluate ballooning and rupture during adiabatic heatup in the temperature range of 1033 to 1200K (1400 to 1700/sup 0/F). The 12 rest rods in the center of the 32-rod bundle were initially pressurized to 4.62 MPa (670 psia) to insure rupture in the correct temperature range. All 12 test rods ruptured with an average strain of 43.7% at the maximum flow blockage elevation of 2.68 m (105.4 in.). Experimental data for the MT-4 transient experiment and post-test measurements and photographs of the fuel are presented in this report.
Date: July 1, 1983
Creator: Wilson, C.L.; Mohr, C.L.; Hesson, G.M.; Wildung, N.J.; Russcher, G.E.; Webb, B.J. et al.
Partner: UNT Libraries Government Documents Department