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A general algorithm for radioactive decay with branching and loss from a medium

Description: Many areas in the field of health physics require evaluation of the change of radionuclide quantity in a medium with time. A general solution to first-order compartmental models is presented in this paper for application to systems consisting of one physical medium that contains any number of radionuclide decay chain members. The general analytical solution to the problem is first described mathematically, and then extended to four applications: (1) evaluation of the quantity of radionuclides as a function of time, (2) evaluation of the time integral of the quantity during a time period, (3) evaluation of the amount in a medium as a function of time following deposition at a constant rate, and (4) evaluation of the time integral of the amount in a medium after deposition at a constant rate for a time. The solution can be applied to any system involving physical transfers from the medium and radioactive chain decay with branching in the medium. The general solution is presented for quantities expressed in units of atoms and activity. Unlike many earlier mathematical solutions, this solution includes chain decay with branching explicitly in the equations.
Date: July 1, 1995
Creator: Strenge, D.L.
Partner: UNT Libraries Government Documents Department

PEDIC - A COMPUTER PROGRAM TO ESTIMATE THE EFFECT OF EVACUATION ON POPULATION EXPOSURE FOLLOWING ACUTE RADIONUCLIDE RELEASES TO THE ATOMSPHERE

Description: The computer program PEDIC is described for estimation of the effect of evacuation on population exposure. The program uses joint frequency, annual average meteorological data and a simple population evacuation model to estimate exposure reduction due to movement of people away from radioactive plumes following an acute release of activity. Atmospheric dispersion is based on a sector averaged Gaussian model with consideration of plume rise and building wake effects. Appendices to the report provide details of the computer program design, a program listing, input card preparation instructions and sample problems.
Date: January 1, 1981
Creator: Strenge, D. L. & Peloquin, R. A.
Partner: UNT Libraries Government Documents Department

Multimedia Environmental Pollutant Assessment System (MEPAS{reg_sign}): Exposure pathway and human health impact assessment models

Description: The Multimedia Environmental Pollutant Assessment System (MEPAS) provides physics-based models for human health risk assessment for radioactive and hazardous pollutants. MEPAS analyzes pollutant behavior in various media (air, soil, groundwater and surface water) and estimates transport through and between media and exposure and impacts to the environment, to the maximum individual, and to populations. MEPAS includes 25 exposure pathway models, a database with information on more than 650 contaminants, and a sensitivity module that allows for uncertainty analysis. Four major transport pathways are considered in MEPAS: groundwater, overland, surface water, and atmospheric. This report describes the exposure pathway and health impact assessment component of MEPAS, which provides an estimate of health impacts to selected individuals and populations from exposure to pollutants. The exposure pathway analysis starts with pollutant concentration in a transport medium and estimates the average daily dose to exposed individuals from contact with the transport medium or a secondary medium contaminated by the transport medium. The average daily dose is then used to estimate a measure of health impact appropriate to the type of pollutant considered. Discussions of the exposure pathway models include the assumptions and equations used to convert the transport medium concentrations to exposure medium concentrations. The discussion for a given exposure pathway defines the transport pathways leading to the exposure, the special processes considered in determining the pollutant concentration in the exposure medium, and the exposure model used to estimate the average daily dose. Models for the exposure pathway and health impact assessments require definition of several parameters. A summary of the notation used for these parameters is provided.
Date: May 1995
Creator: Strenge, D. L. & Chamberlain, P. J.
Partner: UNT Libraries Government Documents Department

Consequence analysis of a hypothetical contained criticality accident in the Hanford Critical Mass Laboratory

Description: The original hazards summary report (i.e., SAR) for the CML addressed the consequences of a hypothetical accidential critical excursion occurring with the experimental assembly room open. That report indicated that the public would receive insignificant radiation exposure regardless of the type of atmospheric condition, while plant personnel could possibly receive exposures greater than the annual exposure limits for radiation workers, when a strong inversion existed. This analysis investigates the consequencs of a hypothetical accident criticality occurring with the experimental assembly room sealed. Due to the containment capabilities designed and built into the critical assembly room, the consequences are greatly reduced below those presented in HW-66266. Despite the incorporation of many extremely conservative assumptions to simplify the analysis, the radiation doses predicted for personnel 100 meters or more distant from the CML are found to be smaller than the annual radiation dose limit for members of the public in uncontrolled areas during routine, nonaccident operations. Therefore, the results of this analysis demonstrate that the occurrence of a hypothetical critical excursion within the sealed experimental assembly room at the Hanford Critical Mass Laboratory presents only a small, acceptable risk to personnel and facilities in the area and no additional safety systems or controls are needed for the continued safe operation of the CML. 11 references, 4 tables. (ACR)
Date: December 1, 1984
Creator: Gore, B.F.; Strenge, D.L. & Mishima, J.
Partner: UNT Libraries Government Documents Department

DITTY - a computer program for calculating population dose integrated over ten thousand years

Description: The computer program DITTY (Dose Integrated Over Ten Thousand Years) was developed to determine the collective dose from long term nuclear waste disposal sites resulting from the ground-water pathways. DITTY estimates the time integral of collective dose over a ten-thousand-year period for time-variant radionuclide releases to surface waters, wells, or the atmosphere. This document includes the following information on DITTY: a description of the mathematical models, program designs, data file requirements, input preparation, output interpretations, sample problems, and program-generated diagnostic messages.
Date: March 1, 1986
Creator: Napier, B.A.; Peloquin, R.A. & Strenge, D.L.
Partner: UNT Libraries Government Documents Department

LADTAP II: technical reference and user guide

Description: This report describes the US Nuclear Regulatory Commission computer program LADTAP II, which performs environmental dose analyses for releases of radioactive effluents from nuclear power plants into surface waters. The analyses estimate radiation dose to individuals, population groups, and biota from ingestion (aquatic foods, water, and terrestrial irrigated foods) and external exposure (shoreline, swimming, and boating) pathways. The calculated doses provide information for National Environmental Policy Act (NEPA) evaluations and for determining compliance with Appendix I of 10 CFR 50 (the ''ALARA'' philosophy). The report also instructs the user in preparing input to the program, describes the mathematical models that are used, and supplies detailed information on program structure and parameters used to modify the program.
Date: April 1, 1986
Creator: Strenge, D.L.; Peloquin, R.A. & Whelan, G.
Partner: UNT Libraries Government Documents Department

RAMS (Risk Analysis - Modular System) methodology

Description: The Risk Analysis - Modular System (RAMS) was developed to serve as a broad scope risk analysis tool for the Risk Assessment of the Hanford Mission (RAHM) studies. The RAHM element provides risk analysis support for Hanford Strategic Analysis and Mission Planning activities. The RAHM also provides risk analysis support for the Hanford 10-Year Plan development activities. The RAMS tool draws from a collection of specifically designed databases and modular risk analysis methodologies and models. RAMS is a flexible modular system that can be focused on targeted risk analysis needs. It is specifically designed to address risks associated with overall strategy, technical alternative, and `what if` questions regarding the Hanford cleanup mission. RAMS is set up to address both near-term and long-term risk issues. Consistency is very important for any comparative risk analysis, and RAMS is designed to efficiently and consistently compare risks and produce risk reduction estimates. There is a wide range of output information that can be generated by RAMS. These outputs can be detailed by individual contaminants, waste forms, transport pathways, exposure scenarios, individuals, populations, etc. However, they can also be in rolled-up form to support high-level strategy decisions.
Date: October 1, 1996
Creator: Stenner, R.D.; Strenge, D.L. & Buck, J.W.
Partner: UNT Libraries Government Documents Department

Description of Multimedia Environment Pollutant Assessment System (MEPAS) version 3.2 modification for the Nuclear Regulatory Commission

Description: The Multimedia Environmental Pollutant Assessment System (MEPAS) is a software tool developed by Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy (DOE) to allow DOE to conduct human health risk analyses nation-wide. This report describes modifications to the MEPAS to meet the requirements of the U.S. Nuclear Regulatory Commission (NRC) staff in their analyses of Site Decommissioning Management Plan sites. In general, these modifications provide the MEPAS, Version 3.2, with the capability of calculating and reporting annual dose/risk information. Modifications were made to the exposure pathway and health impact modules and the water and atmospheric transport modules. Several example cases used to test the MEPAS, Version 3.2, are also presented. The MEPAS, Version 3.2, also contains a new source-term release component that includes models for estimating contaminant loss from three different types of source zones (contaminated aquifer, contaminated pond/surface impoundment, and contaminated vadose zone) due to decay/degradation, leaching, wind suspension, water erosion, overland flow, and/or volatilization. When multiple loss routes are assumed to occur simultaneously, the models account for their interaction and calculate an appropriate pollutant mass budget to each loss route over time.
Date: November 1, 1997
Creator: Buck, J.W.; Strenge, D.L. & Hoopes, B.L.
Partner: UNT Libraries Government Documents Department

Uncertainty and sensitivity analysis of historical vegetation iodine-131 for measurements in 1945--1947; Hanford Environmental Dose Reconstruction Project

Description: The Hanford Environmental Dose Reconstruction (HEDR) Project is developing environmental transport and dose models to estimate the doses to individuals and populations from exposure to radionuclides released from Hanford nuclear facilities since 1944. The validity of these models will be assessed in part by comparing model predictions with environmental measurements of radionuclides. One potentially important set of environmental radionuclide measurements is those made on vegetation samples that, beginning in 1945, were collected on and around the Hanford Site. However, from October 1945 through mid-1948, the available technology permitted the vegetation samples to be measured only for total radioactivity rather than for specific radionuclides. At that time, the factors needed to convert total radioactivities to concentrations ({mu}Ci/kg) of iodine-131, the predominant radionuclide that was released into the air from Hanford stacks in the mid-1940s, were not well known or accurately quantified. A search of historical Hanford records by HEDR Project staff uncovered the original background-corrected radiation measurements, made using a Geiger-Mueller (GM) detector system, for vegetation samples that were collected from October 1945 through early August 1946. HEDR Project staff have developed a model that can be used to convert these radiation measurements to iodine-131 concentrations ({mu}Ci/kg). It is anticipated that this equation will be used to obtain more accurate concentrations of iodine-131 for vegetation for the purpose of validating vegetation iodine-131 concentrations that will be estimated by HEDR Project air-pathway transport models.
Date: March 1, 1994
Creator: Gilbert, R.O.; Mart, E.I.; Strenge, D.L. & Miley, T.B.
Partner: UNT Libraries Government Documents Department

Assessment of effectiveness of geologic isolation systems. ARRRG and FOOD: computer programs for calculating radiation dose to man from radionuclides in the environment

Description: The computer programs ARRRG and FOOD were written to facilitate the calculation of internal radiation doses to man from the radionuclides in the environment and external radiation doses from radionuclides in the environment. Using ARRRG, radiation doses to man may be calculated for radionuclides released to bodies of water from which people might obtain fish, other aquatic foods, or drinking water, and in which they might fish, swim or boat. With the FOOD program, radiation doses to man may be calculated from deposition on farm or garden soil and crops during either an atmospheric or water release of radionuclides. Deposition may be either directly from the air or from irrigation water. Fifteen crop or animal product pathways may be chosen. ARRAG and FOOD doses may be calculated for either a maximum-exposed individual or for a population group. Doses calculated are a one-year dose and a committed dose from one year of exposure. The exposure is usually considered as chronic; however, equations are included to calculate dose and dose commitment from acute (one-time) exposure. The equations for calculating internal dose and dose commitment are derived from those given by the International Commission on Radiological Protection (ICRP) for body burdens and Maximum Permissible Concentration (MPC) of each radionuclide. The radiation doses from external exposure to contaminated farm fields or shorelines are calculated assuming an infinite flat plane source of radionuclides. A factor of two is included for surface roughness. A modifying factor to compensate for finite extent is included in the shoreline calculations.
Date: June 1, 1980
Creator: Napier, B.A.; Roswell, R.L.; Kennedy, W.E. Jr. & Strenge, D.L.
Partner: UNT Libraries Government Documents Department

A risk computation model for environmental restoration activities

Description: A risk computation model useful in environmental restoration activities was developed for the US Department of Energy (DOE). This model, the Multimedia Environmental Pollutant Assessment System (MEPAS), can be used to evaluate effects of potential exposures over a broad range of regulatory issues including radioactive carcinogenic, nonradioactive carcinogenic, and noncarcinogenic effects. MEPAS integrates risk computation components. Release, transport, dispersion, deposition, exposure, and uptake computations are linked in a single system for evaluation of air, surface water, ground water, and overland flow transport. MEPAS uses standard computation approaches. Whenever available and appropriate, US Environmental Protection Agency guidance and models were used to facilitate compatibility and acceptance. MEPAS is a computational tool that can be used at several phases of an environmental restoration effort. At a preliminary stage in problem characterization, potential problems can be prioritized. As more data become available, MEPAS can provide an estimate of baseline risks or evaluate environmental monitoring data. In the feasibility stage, MEPAS can compute risk from alternative remedies. However, MEPAS is not designed to replace a detailed risk assessment of the selected remedy. For major problems, it will be appropriate to use a more detailed, risk computation tool for a detailed, site-specific evaluation of the selected remedy. 15 refs., 2 figs.
Date: January 1, 1991
Creator: Droppo, J.B. Jr.; Strenge, D.L. & Buck, J.W.
Partner: UNT Libraries Government Documents Department

Aquatic pathways model to predict the fate of phenolic compounds

Description: Organic materials released from energy-related activities could affect human health and the environment. To better assess possible impacts, we developed a model to predict the fate of spills or discharges of pollutants into flowing or static bodies of fresh water. A computer code, Aquatic Pathways Model (APM), was written to implement the model. The computer programs use compartmental analysis to simulate aquatic ecosystems. The APM estimates the concentrations of chemicals in fish tissue, water and sediment, and is therefore useful for assessing exposure to humans through aquatic pathways. The APM will consider any aquatic pathway for which the user has transport data. Additionally, APM will estimate transport rates from physical and chemical properties of chemicals between several key compartments. The major pathways considered are biodegradation, fish and sediment uptake, photolysis, and evaporation. The model has been implemented with parameters for distribution of phenols, an important class of compounds found in the water-soluble fractions of coal liquids. Current modeling efforts show that, in comparison with many pesticides and polyaromatic hydrocarbons (PAH), the lighter phenolics (the cresols) are not persistent in the environment. The properties of heavier molecular weight phenolics (indanols, naphthols) are not well enough understood at this time to make similar judgements. For the twelve phenolics studied, biodegradation appears to be the major pathway for elimination from aquatic environments. A pond system simulation (using APM) of a spill of solvent refined coal (SRC-II) materials indicates that phenol, cresols, and other single cyclic phenolics are degraded to 16 to 25 percent of their original concentrations within 30 hours. Adsorption of these compounds into sediments and accumulation by fish was minor.
Date: April 1, 1983
Creator: Aaberg, R.L.; Peloquin, R.A.; Strenge, D.L. & Mellinger, P.J.
Partner: UNT Libraries Government Documents Department

Aquatic Pathways Model to predict the fate of phenolic compounds. Appendixes A through D

Description: Organic materials released from energy-related activities could affect human health and the environment. We have developed a model to predict the fate of spills or discharges of pollutants into flowing or static bodies of fresh water. A computer code, Aquatic Pathways Model (APM), was written to implement the model. The APM estimates the concentrations of chemicals in fish tissue, water and sediment, and is therefore useful for assessing exposure to humans through aquatic pathways. The major pathways considered are biodegradation, fish and sediment uptake, photolysis, and evaporation. The model has been implemented with parameters for the distribution of phenols, an important class of compounds found in the water-soluble fractions of coal liquids. The model was developed to estimate the fate of liquids derived from coal. Current modeling efforts show that, in comparison with many pesticides and polyaromatic hydrocarbons (PAH), the lighter phenolics (the cresols) are not persistent in the environment. For the twelve phenolics studied, biodegradation appears to be the major pathway for elimination from aquatic environments. A pond system simulation of a spill of solvent-refined coal (SRC-II) materials indicates that phenol, cresols, and other single cyclic phenolics are degraded to 16 to 25 percent of their original concentrations within 30 hours. Adsorption of these compounds into sediments and accumulation by fish was minor. Results of a simulated spill of a coal liquid (SRC-II) into a pond show that APM predicted the allocation of 12 phenolic components among six compartments at 30 hours after a small spill. The simulation indicated that most of the introduced phenolic compounds were biodegraded. The phenolics remaining in the aquatic system partitioned according to their molecular weight and structure. A substantial amount was predicted to remain in the water, with less than 0.01% distributed in sediment or fish.
Date: April 1, 1983
Creator: Aaberg, R.L.; Peloquin, R.A.; Strenge, D.L. & Mellinger, P.L.
Partner: UNT Libraries Government Documents Department

Human scenarios for the screening assessment. Columbia River Comprehensive Impact Assessment

Description: Because of past nuclear production operations along the Columbia River, there is intense public and tribal interest in assessing any residual Hanford Site related contamination along the river from the Hanford Reach to the Pacific Ocean. The Columbia River Impact Assessment (CRCIA) was proposed to address these concerns. The assessment of the Columbia River is being conducted in phases. The initial phase is a screening assessment of risk, which addresses current environmental conditions for a range of potential uses. One component of the screening assessment estimates the risk from contaminants in the Columbia River to humans. Because humans affected by the Columbia river are involved in a wide range of activities, various scenarios have been developed on which to base the risk assessments. The scenarios illustrate the range of activities possible by members of the public coming in contact with the Columbia River so that the impact of contaminants in the river on human health can be assessed. Each scenario illustrates particular activity patterns by a specific group. Risk will be assessed at the screening level for each scenario. This report defines the scenarios and the exposure factors that will be the basis for estimating the potential range of risk to human health from Hanford-derived radioactive as well as non-radioactive contaminants associated with the Columbia River.
Date: March 1, 1996
Creator: Napier, B.A.; Harper, B.L.; Lane, N.K.; Strenge, D.L. & Spivey, R.B.
Partner: UNT Libraries Government Documents Department

Toxicology profiles of chemical and radiological contaminants at Hanford

Description: This document summarizes toxicology information required under Section 3.3 (Toxicity Assessment) of HSRAM, and can also be used to develop the short toxicology profiles required in site assessments (described in HSRAM, Section 3.3.5). Toxicology information is used in the dose-response step of the risk assessment process. The dose-response assessment describes the quantitative relationship between the amount of exposure to a substance and the extent of toxic injury or disease. Data are derived from animal studies or, less frequently, from studies in exposed human populations. The risks of a substance cannot be ascertained with any degree of confidence unless dose-response relations are quantified. This document summarizes dose-response information available from the US Environmental Protection Agency (EPA). The contaminants selected for inclusion in this document represent most of the contaminants found at Hanford (both radiological and chemical), based on sampling and analysis performed during site investigations, and historical information on waste disposal practices at the Hanford Site.
Date: July 1, 1995
Creator: Harper, B.L.; Strenge, D.L.; Stenner, R.D.; Maughan, A.D. & Jarvis, M.K.
Partner: UNT Libraries Government Documents Department

Referenced-site environmental document for a Monitored Retrievable Storage facility: backup waste management option for handling 1800 MTU per year

Description: This environmental document includes a discussion of the purpose of a monitored retrievable storage facility, a description of two facility design concepts (sealed storage cask and field drywell), a description of three reference sites (arid, warm-wet, and cold-wet), and a discussion and comparison of the impacts associated with each of the six site/concept combinations. This analysis is based on a 15,000-MTU storage capacity and a throughput rate of up to 1800 MTU per year.
Date: June 1, 1985
Creator: Silviera, D.J.; Aaberg, R.L.; Cushing, C.E.; Marshall, A.; Scott, M.J.; Sewart, G.H. et al.
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

MODELS SELECTED FOR CALCULATION OF DOSES, HEALTH EFFECTS AND ECONOMIC COSTS DUE TO ACCIDENTAL RADIONUCLIDE RELEASES FROM NUCLEAR POWER PLANTS

Description: Models are described for use in site-specific environmental consequence analysis of nuclear reactor accidents of Classes 3 through 9. The models presented relate radioactivity released to resulting doses, health effects, and costs of remedial actions. Specific models are presented for the major exposure pathways of airborne releases, waterborne releases and direct irradiation from activity within the facility buildings, such as the containment. Time-dependent atmospheric dispersion parameters, crop production parameters and other variable parameters are used in the models. The environmental effects are analyzed for several accident start times during the year.
Date: May 1, 1980
Creator: Strenge, D L; Baker, D A; Droppo, J G; McPherson, R B; Napier, B A; Nieves, L A et al.
Partner: UNT Libraries Government Documents Department