Evaluation of uncertainties in radioecological models. [Statistical analysis of selected input parameters to determine source of uncertainties]
Compliance with current environmental radiological standards promulgated to limit routine releases from nuclear facilities is usually determined through the use of mathematical models which are subject to considerable uncertainty. This paper presents results of statistical analyses for seven selected parameters commonly used in environmental radiological assessment models. Estimates of the most probable, median, mean and 99th percentile for each parameter are given and compared to U.S. Nuclear Regulatory Commission default values. The largest uncertainties appear to be associated with aquatic bioaccumulation factors for fresh water fish. Approximately one order of magnitude separates median values and values of the 99th percentile. The uncertainty is also estimated for the annual dose rate predicted by a multiplicative chain model for the transport of molecular iodine-131 via the air-pasture-cow-milk-child's thyroid pathway, using lognormal statistics to combine the uncertainties associated with eight input parameters and assuming that the structure of the model is correct. The value for the 99th percentile is ten times larger than the median value of the predicted dose normalized for a given air concentration of /sup 131/I/sub 2/. About 72% of the uncertainty in this model is contributed by the dose conversion factor and the milk transfer coefficient. Considering the difficulties in obtaining a reliable quantification of the true uncertainties in model predictions, methods for taking these uncertainties into account when determining compliance with regulatory statutes are discussed.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6341858
- Report Number(s):
- CONF-780133-2
- Country of Publication:
- United States
- Language:
- English
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11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
510302* -- Environment
Terrestrial-- Radioactive Materials Monitoring & Transport-- Terrestrial Ecosystems & Food Chains-- (-1987)
520302 -- Environment
Aquatic-- Radioactive Materials Monitoring & Transport-- Aquatic Ecosystems & Food Chains-- (-1987)
54 ENVIRONMENTAL SCIENCES
560171 -- Radiation Effects-- Nuclide Kinetics & Toxicology-- Man-- (-1987)
560172 -- Radiation Effects-- Nuclide Kinetics & Toxicology-- Animals-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR
ANIMAL FEEDS
ANIMALS
AQUATIC ECOSYSTEMS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL ACCUMULATION
BIOLOGICAL MATERIALS
BODY
BODY FLUIDS
CATTLE
CHILDREN
COWS
DATA
DATA FORMS
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DOSE RATES
DOSES
ECOLOGICAL CONCENTRATION
ECOLOGY
ECOSYSTEMS
ENDOCRINE GLANDS
ENVIRONMENTAL TRANSPORT
EVALUATED DATA
FISHES
FLUIDS
FOOD
FOOD CHAINS
FORAGE
GASES
GLANDS
INFORMATION
INTERMEDIATE MASS NUCLEI
IODINE 131
IODINE ISOTOPES
ISOLATED VALUES
ISOTOPES
MAMMALS
MAN
MASS TRANSFER
MATHEMATICAL MODELS
MATHEMATICS
MILK
NUCLEAR FACILITIES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANS
PLANTS
PRIMATES
RADIATION DOSES
RADIOACTIVE EFFLUENTS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
RADIOECOLOGICAL CONCENTRATION
RADIOECOLOGY
RADIOISOTOPES
RADIONUCLIDE KINETICS
RADIONUCLIDE MIGRATION
RUMINANTS
STATISTICS
TERRESTRIAL ECOSYSTEMS
THYROID
VERTEBRATES
WASTES