S.J. Cotter

Oak Ridge National Laboratory

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Charles W. Miller

Cleveland Clinic

D.E. Fields

Roane State Community College

C.A. Little

Grand Junction VA Medical Center

Curtis C. Travis

Food Safety and Inspection Service

A.P. Watson

Oak Ridge National Laboratory

M. L. Randolph

Oak Ridge National Laboratory

L.M. McDowell-Boyer

Oak Ridge National Laboratory

R.E. Moore

Massachusetts General Hospital

P.L. Ziemer

Eastern Michigan University

R.B. Gammage

Oak Ridge National Laboratory

Cooperative Institutions

Oak Ridge National Laboratory

United States Department of Energy

United States Department of Commerce

University of Tennessee at Knoxville

Washington State University

Purdue University West Lafayette

Science Applications International Corporation (United States)

Martin Marietta Materials (United States)

Health Physics Society

Oak Ridge Associated Universities

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Comparison of observed and predicted short-term tracer gas concentrations in the atmosphere

S.J. Cotter Charles W. Miller Wei-Cheng Lin

The Savannah River Laboratory is in the process of conducting a series of atmospheric tracer studies. The inert gas sulfurhexafluoride is released from a height of 62 m for 15 min and concentrations in air are measured on sampling arcs up to 30 km downwind of the release point. Maximum 15 min. air concentrations from 14 of these tracer tests have been compared with the ground-level, centerline air concentration predicted with a Gaussian plume atmospheric transport model using eight different sets of atmospheric dispersion parameters. Preliminary analysis of the results from these comparisons indicates that the dispersion parameters developed at Juelich, West Germany, based on tracers released from a height of 50 m, give the best overall agreement between the predicted and observed values. The median value of the ratio of predicted to observed air concentrations for this set of parameters is 1.3, and the correlation coefficient between the log of the predictions and the log of the observations is 0.72. For the commonly used Pasquill-Gifford dispersion parameters, the values of these same statistics are 4.4 and 0.68, respectively. The Gaussian plume model is widely used to predict air concentrations resulting from short-term radionuclide release to the atmosphere. The resultsmore » of comparisons such as these must be considered whenever the Gaussian model is used for such purposes. 22 references, 3 tables.« less

TRACER

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Methodology for the objective validation of model performance, with an application to atmospheric transport models

D.E. Fields Charles W. Miller S.E. Kurtz S.J. Cotter

Evaluation of model performance may consist of objectively comparing corresponding pairs of observed and predicted values. This defensible provided bias has been identified and removed from the data and that the data are distributed normally or may be transformed so as to be distributed normally. Recent modifications to the TERPED computer code have made this program applicable to the analysis and transformation of small and large data sets. TERPED was used to perform Kolmogorov-Smirnov and graphical analyses of mormalized crosswind - integrated ground-level air concentration measurements of zinc sulfide particles released from a height of 111 m at Hanford, Washington as reported by Nickola. Our analysis demonstrates that the data may be considered to be distributed log-normally (..cap alpha.. = 0.014), but not normally (..cap alpha.. = 0.86). Simulations of particulate transport used each of three methods of stability determination - (1) vertical temperature gradient, (2) standard deviation of wind direction, and (3) vertical temperature gradient and wind speed - and each of five dispersion parameterizations. Model performance was evaluated by computing the root mean squared difference of log-transformed value pairs, and it was shown that method (2) and Julich (100m) dispersion values gave the best results. For comparison, themore » models were evaluated using the nontransformed observed and predicted values, and it was shown that application of this inappropriate approach yields ambiguous results that suggest markedly different conclusions.« less

Atmospheric instability

Crosswind

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Comparison of Fast Neutron-induced Tracks in Plastics Using the Electrochemical Etching Method

Health Physics (1979)

S.J. Cotter R.B. Gammage J.H. Thorngate P.L. Ziemer

Four plastics have been examined by the electrochemical etching method for their suitability in registering fast neutron-induced recoil particle tracks. The plastics are cellulose acetate, cellulose triacetate, cellulose acetobutyrate and polycarbonate. Cellulose acetate and triacetate display high levels of water absorptivity during etching while the acetobutyrate foils cracked due to electromechanical stresses at high frequencies (> 500 Hz). The clarity of the etched tracks is superior in the polycarbonate foils, suggesting the latter as the generally preferred dosimeter for fast neutrons.

Cellulose triacetate

Polycarbonate

Cellulose acetate

10.1097/00004032-197909000-00012

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Validation of the AIRDOS-EPA computer code by simulating intermediate range transport of 85Kr from the Savannah River Plant

Atmospheric Environment (1967) (1984)

D.E. Fields Charles W. Miller S.J. Cotter

10.1016/0004-6981(84)90188-4

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Preliminary Draft: Environmental Impact Statement for Hot Fuels Engineering Laboratory.

J. W. Boyle Joseph A. Carpenter S.J. Cotter F.E. Harrington N.E. Hinkle

results in Volume 1 from several site-specific appendixes. Volume 2 of the EIS, which supports the INEL-specific decision, describes environmental impacts for various environmental restoration, waste management, and spent nuclear fuel management alternatives for planning years 1995 through 2005. This Appendix B to Volume 1 considers the impacts on the INEL environment of the implementation of various DOE-wide spent nuclear fuel management alternatives. The Naval Nuclear Propulsion Program, which is a joint Navy/DOE program, is responsible for spent naval nuclear fuel examination at the INEL. For this appendix, naval fuel that has been examined at the Naval Reactors Facility and turned over to DOE for storage is termed naval-type fuel. This appendix evaluates the management of DOE spent nuclear fuel including naval-type fuel.

Environmental impact statement

10.2172/12199816

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Simulation of Kr-85 transport at Savannah River

S.J. Cotter D.E. Fields Charles W. Miller

The AIRDOS-EPA computer code uses a modified Gaussian plume equation to estimate air concentrations from the release of up to 36 radionuclides and couples these results with the terrestrial model developed in US Nuclear Regulatory Commission Regulatory Guide 1.109 to estimate the annual dose to the general public. One year of weekly average YVKr concentrations observed at 13 sampling stations around the Savannah River Plant have been used to validate the atmospheric transport portion of AIRDOS-EPA. The predicted annual average concentration at each station exceeded the observed value in every case. The average overprediction factor was 2.4 (range 1.4 to 3.4). Pearson's correlation between pairs of logarithms of annualized observed and predicted values was r = 0.93. As the averaging time of the prediction decreases, however, the uncertainty in the prediction increases. For example, the monthly values show more scatter than do annual or seasonal values. When seasonal observed and predicted values were compared, the authors found increasing agreement as they compared spring, summer, fall and winter values.

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Potential radiation dose to man from recycle of metals reclaimed from a decommissioned nuclear power plant

Francis O’Donnell S.J. Cotter D.C. Kocher E.L. Etnier A. T. Watson

A generic methodology is presented for estimating potential radiation doses to man from recycling radioactively contaminated scrap metals that may be reclaimed from decommissioned nuclear facilities. The heart of the methodology is a set of tables of radionuclide-specific, radiation-dose factors that may be used to estimate doses to individuals and population groups from recycling any radioactively contaminated scrap metal. The dose factors are based on detailed radiological assessments of several options for recycling scrap metals. Assessments were made for each of 27 nuclides which might contaminate metals recovered from a decommissioned nuclear power plant. Each assessment was of a reference quantity of scrap metal that was assumed to contain a reference level of a potentially contaminative radionuclide. The radiological assessments are described, and the dose factors in assessments of many recyclable metals, for estimating critical-organ doses from the given dose factors that were derived for total-body exposures, and for ranking the radionuclides considered according to their relative potential for delivering radiation doses to man.

Scrap

Nuclide

Nuclear decommissioning

10.2172/6451074

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Comparison of observed and predicted normalized air concentrations for 56-m releases of fluorescein particles

OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) (1980)

Charles W. Miller C.A. Little S.J. Cotter

Centerline ground-level normalized air concentration measurements made at Hanford, Washington, for the short-term release of fluorescein particles from a height of 56 m were compared with a Gaussian plume atmospheric dispersion model using two different sets of dispersion parameters and two different methods of classifying atmospheric stability. The ratio of the predicted air concentration to the observed air concentration is strongly dependent on the downwind distance being considered. All four methods have a tendency to underpredict near the source, sometimes by many orders of magnitude, and to overpredict at the farthest distances considered (12.8 km). Such a tendency must be taken into account when assessing the impact (on man) of short-term pollutant releases to the atmosphere. In general, the results of this study highlight the difficulty of choosing a set of dispersion parameters and estimating atmospheric stability for use in assessment activities. These results also show, however, that such specification is important in determining the accuracy of Gaussian plume atmospheric dispersion model predictions.

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Natural and technologically enhanced sources of radon-222

Nucl. Saf.; (United States) (1979)

Curtis C. Travis A.P. Watson L.M. McDowell-Boyer S.J. Cotter M. L. Randolph

An assessment of /sup 222/Rn releases (curies/year) from major natural and technologically enhanced sources in the United States is presented. The resulting inhalation population dose commitments to the bronchial epithelium of the lung (lung-rem) are also estimated. The sources of radon considered are natural soil, evapotranspiration, potable water supplies, building materials, natural gas, uranium mining and milling, coal and phosphate mining, phosphate fertilizer, liquefied petroleum gas, geothermal power facilities, coal-fired power plants, and gas and oil wells. The most important natural source of /sup 222/Rn is decay of /sup 226/Ra in the soil and rocks of the earth's crust. This source results in approximately 40% of the total population dose from all sources of radon. The largest technoligcally enhanced contributor to population dose is airborne /sup 222/Rn in building interiors, which is estimated to contribute 55% to the total population exposure to /sup 222/Rn. Each of the other sources is estimated to contribute less than 3% to the total.

Natural radioactivity

Soil gas

Radon gas

Radium

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Population dose estimation from a hypothetical release of 2. 4 x 10/sup 6/ curies of noble gases and 1 x 10/sup 4/ curies of /sup 131/I at the Three Mile Island Nuclear Station, Unit 2

C. D. Berger B. Lane S.J. Cotter Charles W. Miller S. R. Glandon

Beginning on March 28, 1979, a sequence of events occurred at the Three Mile Island Nuclear Station Unit 2 (TMINS-2) nuclear power reactor which resulted in the accidental release of approximately 2.4 x 10/sup 6/ Ci of noble gases and 13 to 15 Ci /sup 131/I. A comprehensive study of this incident has been reported by the President's Commission on the Accident at Three Mile Island. As part of this study, the Technical Assessment Task Group for the Commission addressed a series of alternative event scenarios, including the potential for a higher release of /sup 131/I. As a continuation of this task, this report presents the estimated collective dose to the population within 50 miles of TMINS-2 from a hypothetical release of 2.4 x 10/sup 6/ Ci of noble gases and 1 x 10/sup 4/ Ci /sup 131/I by the methodology of atmospheric dispersion modeling and population dose estimation through the inhalation, ingestion and immersion exposure pathways.

Noble gas

Nuclear explosion

10.2172/6048410

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