Dose Estimation for Exposure to Radioactive Fallout from Nuclear Detonations

Steven L. Simon1, André Bouville2, Harold L. Beck3, Lynn R. Anspaugh4, Kathleen M. Thiessen5, F. Owen Hoffman5, Sergey Shinkarev6

(1. National Cancer Institute, National Institutes of Health, Bethesda, MD;2. National Cancer Institute, National Institutes of Health, Bethesda, MD (retired);3. US Department of Energy (retired), New York, NY;4. Department of Radiology, University of Utah (Emeritus), Henderson, NV;5. Oak Ridge Center for Risk Analysis, Inc., Oak Ridge, TN;6. State Research Center—Burnasyan Federal Medical Biophysical Center, Federal Medical Biological Agency, Moscow, Russian Federation)

Abstract:In recent years, the prospects that a nuclear device might be detonated due to a regional or global political conflict, by violation of present nuclear weapons test ban agreements, or due to an act of terrorism, has increased. Thus, the need exists for a well conceptualized, well described, and internally consistent methodology for dose estimation that takes full advantage of the experience gained over the last 70 y in both measurement technology and dose assessment methodology. Here, the models, rationale, and data needed for a detailed state-of-the-art dose assessment for exposure to radioactive fallout from nuclear detonations discussed in five companion papers are summarized. These five papers present methods and data for estimating radionuclide deposition of fallout radionuclides, internal and external dose from the deposited fallout, and discussion of the uncertainties in the assessed doses. In addition, this paper includes a brief discussion of secondary issues related to assessments of radiation dose from fallout. The intention of this work is to provide a usable and consistent methodology for both prospective and retrospective assessments of exposure from radioactive fallout from a nuclear detonation.

Keywords: accidents; nuclear; dose assessment; fallout; health effects Health Phys. 122(1):1-20; 2022

AMethodforEstimatingtheDepositionDensityofFalloutontheGroundandonVegetationfromaLow-yield,Low-altitudeNuclearDetonation

Harold L. Beck1, André Bouville2, Steven L. Simon3, Lynn R. Anspaugh4, Kathleen M. Thiessen5, Sergey Shinkarev6, Konstantin Gordeev7

(1.US Department of Energy (retired), New York, NY;

2. National Cancer Institute (retired), Bethesda, MD;

3. National Cancer Institute, Bethesda, MD;

4. Department of Radiology, University of Utah (Emeritus), Henderson, NV;

5. Oak Ridge Center for Risk Analysis, Inc., Oak Ridge, TN;

6. State Research Center—Burnasyan Federal Medical Biophysical Center, Federal Medical Biological Agency, Moscow, Russian Federation;

7. State Research Center—Institute of Biophysics of the Ministry of Health, Moscow, Russian Federation (deceased))

Abstract:This paper describes a relatively simple model developed from observations of local fallout from US and USSR nuclear tests that allows reasonable estimates to be made of the deposition density (activity per unit area) on both the ground and on vegetation for each radionuclide of interest produced in a nuclear fission detonation as a function of location and time after the explosion. In addition to accounting for decay rate and in-growth of radionuclides, the model accounts for the fractionation (modification of the relative activity of various fission and activation products in fallout relative to that produced in the explosion) that results from differences in the condensation temperatures of the various fission and activation products produced in the explosion. The proposed methodology can be used to estimate the deposition density of all fallout radionuclides produced in a low yield, low altitude fission detonation that contribute significantly to dose. The method requires only data from post-detonation measurements of exposure rate (or beta or a specific nuclide activity) and fallout time-of-arrival. These deposition-density estimates allow retrospective as well as rapid prospective estimates to be made of both external and internal radiation exposure to downwind populations living within a few hundred kilometers of ground zero, as described in the companion papers in this volume.

Keywords: exposure; radiation; fallout; fission products; health effects

Health Phys. 122(1):21-53; 2021

AMethodologyforEstimatingExternalDosestoIndividualsandPopulationsExposedtoRadioactiveFalloutfromNuclearDetonations

André Bouville1, Harold L. Beck2, Lynn R. Anspaugh3, Konstantin Gordeev4, Sergey Shinkarev5, Kathleen M. Thiessen6, F. Owen Hoffman6, Steven L. Simon7

(1.National Cancer Institute, National Institutes of Health, Bethesda, MD (retired);

2. Department of Energy (retired), New York, NY;

3. Department of Radiology, University of Utah (Emeritus), Henderson, NV;

4. State Research Center—Institute of Biophysics of the Ministry of Health, Moscow, Russian Federation (deceased);

5. State Research Center—Burnasyan Federal Medical Biophysical Center, Federal Medical Biological Agency, Moscow, Russian Federation;

6. Oak Ridge Center for Risk Analysis, Inc., Oak Ridge, TN;

7. National Cancer Institute, National Institutes of Health, Bethesda, MD)

Abstract:A methodology of assessment of the doses from external irradiation resulting from the ground deposition of radioactive debris (fallout) from a nuclear detonation is proposed in this paper. The input data used to apply this methodology for a particular location are the outdoor exposure rate at any time after deposition of fallout and the time-of-arrival of fallout, as indicated and discussed in a companion paper titled “A Method for Estimating the Deposition Density of Fallout on the Ground and on Vegetation from a Low-yield Low-altitude Nuclear Detonation.” Example doses are estimated for several age categories and for all radiosensitive organs and tissues identified in the most recent ICRP publications. Doses are calculated for the first year after the detonation, when more than 90% of the external dose is delivered for populations close to the detonation site over a time period of 70 y, which is intended to represent the lifetime dose. Modeled doses in their simplest form assume no environmental remediation, though modifications can be introduced. Two types of dose assessment are considered: (1)initial, for a rapid but only approximate dose estimation soon after the nuclear detonation; and (2)improved, for a later, more accurate, dose assessment following the analysis of post-detonation measurements of radiation exposure and fallout deposition and the access of information on the lifestyle of the exposed population.

Keywords: accidents; nuclear; dose; external; fallout; radiation dose

Health Phys. 122(1):54-83; 2021

AMethodologyforCalculationofInternalDoseFollowingExposuretoRadioactiveFalloutfromtheDetonationofaNuclearFissionDevice

Lynn R. Anspaugh1, André Bouville2, Kathleen M. Thiessen3, F. Owen Hoffman4, Harold L. Beck5, Konstantin I. Gordeev6, Steven L. Simon7

(1.Department of Radiology, University of Utah, Emeritus, Henderson, NV;

2. National Cancer Institute, Retired, Bethesda, MD;

3. Oak Ridge Center for Risk Analysis, Oak Ridge, TN;

4. Oak Ridge Center for Risk Analysis, Retired, Oak Ridge, TN;

5. Department of Energy, Retired, New York, NY;

6. Burnasyan Federal Medical Biophysical Center, Deceased, Moscow, Russian Federation;

7. National Cancer Institute, Bethesda, MD)

Abstract:The purpose of this paper is to provide a methodology for the calculation of internal doses of radiation following exposure to radioactive fallout from the detonation of a nuclear fission device. Reliance is on methodology previously published in the open literature or in reports not readily available, though some new analysis is also included. Herein, we present two methodologic variations: one simpler to implement, the other more difficult but more flexible. The intention is to provide in one place a comprehensive methodology. Pathways considered are (1) the ingestion of vegetables and fruits contaminated by fallout directly, (2) the ingestion of vegetables and fruits contaminated by continuing deposition by rain- or irrigation-splash and resuspension, (3) the ingestion of vegetables and fruits contaminated by absorption of radionuclides by roots after tillage of soil, (4) the non-equilibrium transfer of short-lived radionuclides through the cow-milk and goat-milk food chains, (5) the equilibrium transfer of long lived radionuclides through milk and meat food chains, and (6) inhalation of descending fallout. Uncertainty in calculated results is considered. This is one of six companion papers that describe a comprehensive methodology for assessing both external and internal dose following exposures to fallout from a nuclear detonation. Input required to implement the dose-estimation model for any particular location consists of an estimate of the post-detonation external gamma-exposure rate and an estimate of the time of arrival of the fallout cloud. The additional data required to make such calculations are included in the six companion papers.

Keywords: fallout; ingestion; internal dose; nuclear weapons

Health Phys. 122(1):84-124; 2021

DoseCoefficientsforInternalDoseAssessmentsforExposuretoRadioactiveFallout

Dunstana R. Melo1, Luiz Bertelli2, Shawki A. Ibrahim3, Lynn R. Anspaugh4, André Bouville5, Steven L. Simon6

(1.Melohill Technology;

2. Los Alamos National Laboratory, NM;

3. Colorado State University, Department of Environmental and Radiological Health Sciences (Emeritus), CO;

4. University of Utah, Emeritus, Henderson, NV;

5. National Cancer Institute, National Institutes of Health (ret.), MD;

6. National Cancer Institute, National Institutes of Health, MD)

Abstract:This paper presents values as well as the bases for calculating internal dose coefficients suitable for estimating organ doses from the exposure to radioactive fallout that could result from the detonation of a nuclear fission device. The 34 radionuclides discussed are the same as those given in a priority list of radionuclides for fallout dose assessments presented in a companion overview paper. The radionuclides discussed are those that are believed to account for a preponderance of the organ doses that might be received by intake by persons of all ages (including in utero and via breast feeding for infants) following exposure to radioactive fallout. The presented dose coefficients for ingestion account for age and include modifications for variations in solubility with distance as discussed previously in the literature, and those for inhalation similarly account for age, solubility, and particle sizes that would be relevant at various distances of exposure as discussed in a companion paper on ingestion dose methods. The proposed modifications peculiar to radioactive fallout account for systematic changes in solubility and particle sizes with distance from the site of detonation, termed here as the region of “l(fā)ocal fallout” and the region “beyond local fallout”. Brief definitions of these regions are provided here with more detailed discussion in a companion paper on estimating deposition of fallout radionuclides. This paper provides the dose coefficients for ingestion and inhalation (for particle sizes of 1 μm, 5 μm, 10 μm, and 20 μm) for the region “l(fā)ocal fallout”. These dose coefficients for “l(fā)ocal fallout” are specific for particles formed in a nuclear explosion that can be large and have radionuclides, particularly the more refractory ones, distributed throughout the volume where the radionuclide has reduced solubility. The dose coefficients for the region “beyond local fallout” are assumed to be the ones published by the International Commission on Radiological Protection (ICRP) in 1995. Comparisons of the presented dose coefficients are made with values published by the ICRP.

Keywords: accidents; nuclear; dose; absorbed; fallout; internal dose

Health Phys. 122(1):125-235; 2021

ParameterValuesforEstimationofInternalDosesfromIngestionofRadioactiveFalloutfromNuclearDetonations

Kathleen M. Thiessen1, F. Owen Hoffman1, André Bouville2, Lynn R. Anspaugh3, Harold L. Beck4, Steven L. Simon5

(1.Oak Ridge Center for Risk Analysis, Inc., 102 Donner Drive, Oak Ridge, TN 37830;

2.National Cancer Institute, National Institutes of Health, Bethesda, MD (retired);

3.University of Utah, Emeritus, Henderson, NV;

4.New York, NY (USDOE, retired);

5.National Cancer Institute, National Institutes of Health, Bethesda, MD)

Abstract:This paper suggests values or probability distributions for a variety of parameters used in estimating internal doses from radioactive fallout due to ingestion of food. Parameters include those needed to assess the interception and initial retention of radionuclides by vegetation, translocation of deposited radionuclides to edible plant parts, root uptake by plants, transfer of radionuclides from vegetation into milk and meat, transfer of radionuclides into non-agricultural plants and wildlife, and transfer from food and drinking water to mother's milk (human breast milk). The paper includes discussions of the weathering half-life for contamination on plant surfaces, biological half-lives of organisms, food processing (culinary factors), and contamination of drinking water. As appropriate, and as information exists, parameter values or distributions are specific for elements, chemical forms, plant types, or other relevant characteristics. Information has been obtained from the open literature and from publications of the International Atomic Energy Agency. These values and probability distributions are intended to be generic; they should be reviewed for applicability to a given location, time period, or season of the year, as appropriate. In particular, agricultural practices and dietary habits may vary considerably both with geography and over time in a given location.

Keywords: fallout; environmental transport; food chain; ingestion

Health Phys. 122(1):236-268; 2021