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Introduction
Education
January 1971 - August 1974
September 1969 - January 1971
September 1959 - June 1963
Publications
Publications (54)
A common form of count-rate detection limits contains a propagation of uncertainty error. This error originated in methods to minimize uncertainty in the subtraction of the blank counts from the gross sample counts by allocation of blank and sample counting times. Correct uncertainty propagation showed that the time allocation equations have no sol...
A multistage virtual impactor has been designed and fabricated consisting of two separation stages yielding three particle size classes. Efficiency and loss curves have been experimentally determined at ambient conditions for each stage. The small physical size and ability to operate at low flow rates make the impactor very versatile. The uses for...
Various options were considered for surveying and real-time monitoring for airborne plutonium for optimum protection of personnel. Placement of samplers, dilution factors, and analysis time were considered in the strategy for achieving regulatory compliance and maintaining internal dose as low as reasonably achievable (ALARA). It was found that pro...
An alternative to the accepted method for calculating detection limits is presented that avoids difficulties often encountered with few total counts. In particular, excessive false positives and large relative uncertainty in the signal determination are prevented. The usually accepted method did not fully incorporate Poisson statistics in the deriv...
The objective of science is to make a credible prediction. A prediction is subject to probabilistic effects that degrade the quality of the prediction. Probability is the manifestation of lack of control. Identifying the aspects of a prediction that are subject to probability allows for exerting control where necessary. Statistics is useful in data...
The Oak Ridge National Laboratory (ORNL) separated radioactive lanthanum (RaLa) fission products from irradiated uranium from 1944 through 1956. A consequence of the separation was the atmospheric release of 131 I. A reconstruction of doses from the 131 I releases was performed to investigate the risk of thyroid cancer to individuals who resided ne...
Iodine-129 is a natural, long-lived radioisotope with a half-life of 15.7 million years. There is an added 129 I background from weapons testing produced by fissioning of 235 U (0.68% of fissions) and 239 Pu (1.6% of fissions). The area concentration of weapons test 129 I varies depending upon distance and air patterns from the test sites. Local so...
Granite countertops and other natural materials used in building construction may have concentrations of uranium series radionuclides that are higher than the local average background. Further, the concentration within the material may be highly variable and may contain inclusions that have concentrations much higher than the material average. Such...
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Phosphorus slag containing elevated concentrations of radionuclides in the uranium series with radium-226 ranging from 750 to 1100 Bq/kg has been used in Southeastern Idaho communities as a construction material. An exposure study was conducted in the region to identify residences that incorporated phosphorus slag in the construction material, to d...
Ecological studies of health effects due to agent exposure are generally considered to be a blunt instrument of scientific investigation, unfit to determine the "true" exposure-effect relationship for an agent. Based on this widely accepted tenet, ecological studies of the correlation between the local air concentration of radon and the local lung...
Numerous past studies of waterborne radon sampling and measurement techniques have concluded that today's most frequently used sample collection methods are cumbersome and/or require highly trained and careful technicians. All are prone to error if there is the slightest deviation from the prescribed procedure. Obtaining reasonable accuracy and pre...
In cleanup operations and environmental surveillance efforts, a level of concern usually specifies a concentration limit for a particular radionuclide above which some action may be warranted. It is critical that the analytical method selected for measurements has a detection limit well below the action level. This is to guarantee that the techniqu...
In situ gamma spectrometry is an efficient method for monitoring the progress of cleanup activities for radioactive contaminants in surface soil and for evaluating the attainment of cleanup standards. However, desired data precision and accuracy must be specified for such a detection system prior to the operation to ensure that the level of uncerta...
The linear dose-effect relationship was introduced as a model for the induction of cancer from exposure to nuclear radiation. Subsequently, it has been used by analogy to assess the risk of chemical carcinogens also. Recently, however, the model for radiation carcinogenesis has come increasingly under attack because its calculations contradict the...
The linear no-threshold model for radiation effects was introduced as a conservative model for the design of radiation protection programs. The model has persisted not only as the basis for such programs, but has come to be treated as a dogma and is often confused with scientific fact. In this examination a number of serious problems with the linea...
One of the main steps in an uncertainty analysis is the selection of appropriate probability distribution functions for all stochastic variables. In this paper, criteria for such selections are reviewed, the most important among them being any a priori knowledge about the nature of a stochastic variable, and the Central Limit Theorem of probability...
Risk management implies that the risk manager can, by his actions, exercise at least a modicum of control over the risk in question. In the terminology of control theory, a management action is a control signal imposed as feedback on the system to bring about a desired change in the state of the system. In the terminology of risk management, an act...
About ten years ago, it was demonstrated that the presence of salt aerosols in the atmosphere of the WIPP leads to the special degradation of the alpha lines of radon decay products, which are attached to the salt and collected on the filter of continuous air monitors. This spectral degradation leads to false alarms in the air monitor due to alpha...
Radiation measurements on items excavated from a radioactive-waste burial ground were part of a field test of excavation techniques for the cleanup of subsurface sites. The waste resulted from plutonium production for nuclear weapons at Hanford, WA. The radiation measurements investigated techniques for classifying bulk waste for placement into a p...
Radiation measurements on items excavated from a radioactive-waste burial ground were part of a field test of excavation, radiation screening, and waste sorting techniques being evaluated for the cleanup of Hanford burial sites. The radiation measurements investigated techniques for classifying bulk waste for placement into an environmental restora...
TF 9408-215 M (Received 23 Augttst I99l: acceptcd I0 Octobcr Ig94) Thc relationship betwecn quantitative risk asscssmcnt and the scicntific method is investigarcd. Thc intcnr of this paper is to stimulatc thc discussion on how to apply the scientific mcthod to risk assessment and how to deal with thc rcsults of this application. Thc qucstion of whe...
A definite angular dependence of shallow dose from energetic electrons was observed when measuring the angular response of several detectors. This angular dependence of dose appeared to be fundamental, not a detector artifact. The theoretical response of a detector is discussed and compared to measurements of shallow dose with tissue and phantom re...
Personal air samplers are used for more convenient breathing zone sampling of individuals over several hour time periods. Personal air sampling pumps must meet minimum performance levels under all working conditions to be suitable for use in radiation protection programs. In addition, the pumps should be simple to operate and as comfortable to wear...
Meaningful interpretation of widely variable airborne contamination measurements is a difficult problem. Exposure limits, action levels, etc., are rigid interpretations of inherently variable environmental or workplace conditions, and are useful for control and regulatory compliance evaluations. Such limits force actions to reduce contamination, bu...
There are situations where it is inconvenient or impossible to place air sampling equipment in the location to be sampled. Also, fast response time for source concentration measurements may be required, where diffusion to a detector is too slow and the resulting dilution would cause a reduction in sensitivity. Sampling lines may be used to transpor...
A multistage virtual impactor has been designed and fabricated consisting of two separation stages, yielding three particle size classes. Efficiency and loss curves have been experimentally determined at ambient conditions for each stage. The small physical size and ability to operate at low flow rates make the impactor very versatile. The uses for...
Sharp-line luminescence of titanium impurities in the system ZrO-Y2O3 has been investigated. Cubic ZrO2 and Zr3Y4O12 exhibit broadening of the luminescence lines which can be attributed to structural disorder. The sharp-line luminescence also provides a method for determining the phonon modes in cubic ZrC2.
Raman and luminescence spectroscopy with the use of the MOLE microprobe has been used to characterize ZrOâ originating from oxidized fuel-rod cladding in nuclear accidents. Micro-Raman analysis of samples from Three Mile Island Unit 2 and the Power Burst Facility identified tetragonal and cubic ZrOâ. The tetragonal and cubic phases are high-tempera...
Recommended applications for personal air sampling in NRC licensee radiation protection programs are presented. The recommendations are based on performance tests of currently available samplers, a review of research and regulatory literature, and a survey of current licensee air-sampling programs. The performance tests show that personal air sampl...
The results of a program to provide an experimental data base for estimating the radiological consequences from a hypothetical sabotage attack on a light-water-reactor spent fuel shipping cask in a densely populated area are presented. The results of subscale and full-scale experiments in conjunction with an analytical modeling study are described....
A portable beta-gamma dose rate instrument capable of tissue-equivalent dose rate measurements in mixed beta-gamma fields has been developed and tested. The detector is a 5 mg/cm2-thick plastic scintillator with a 4 mg/cm2-window and a 1 cm-thick lucite light pipe to achieve the backscatter geometry required for this application. Pulse shape discri...
The Molecular Optical Laser Examiner (MOLE) uses micro-Raman spectroscopy to identify the chemical species and crystalline states of sample particles. The purpose of examining TMI-2 samples with the MOLE is threefold: to determine the various chemical species resulting from a nuclear release accident; to better explain the presence, transport, and...
The diffusion of gold through polycrystalline silver in the form of thin films at annealing temperatures far from the melting point was monitored at the silver-vacuum interface with an electron spectrometer (ESCA) as a function of time and was verified further by serial sectioning with argon etching. The diffusion can be characterized by a grain bo...
Using a Raman microprobe, samples were analyzed from Three Mile Island Unit 2 (TMI-2). The purpose of examining TMI-2 samples is threefold: to determine the various chemical species resulting from a nuclear release accident; to better explain the presence, transport, and consequences of release to the environment of specific chemical species; and t...
We have experimented with yttrium fluorescence in the various crystalline phases of ZrOâ. This work was a direct result of micro-Raman analysis of filter debris samples from Power Burst Facility. The yttrium fluorescence in the micro-Raman spectra provides a method for differentiating between fabricated zirconia and oxidized fuel-rod cladding. We c...
The current 2-chip TLD personnel dosimeter in use at Three Mile Island (TMI) has been shown inadequate for the anticipated high beta/gamma fields during TMI recovery operations in some areas. This project surveyed the available dosimeter systems, set up an Idaho National Engineering Laboratory (INEL) prototype system, and compared this system with...
The transport of radioactive aerosols was studied using equipment, collectively called the Helium jet, that has been constructed to provide basic nuclear physics data on fission product nuclides. The transport of the fission products in the system depends on their attachment to aerosol particles. The system consists of 1) a tube furnace which gener...
Two main changes in risk analysis are increasingly beginning to influence the manner in which, in the perception of scientists, low-dose modeling of radiation carcinogenesis is supposed to be done. In the past, efforts to model radiation risks have been carried out under the banner of scientific endeavors. On closer inspection, however, it has beco...
A luminescence microprobe was developed to supplement measurements from a Raman microprobe. Many crystals that are non-Raman active luminesce, which yields both chemical and crystalline information. This instrument was built specifically for those crystals having the NaCl structure and for Raman active crystals that exhibit impurity luminescence. L...
Following a nuclear accident there is a need to determine the chemical composition of materials in liquid, solid and gaseous form, the crystalline structure of solids, the size and chemical composition of particles, and the chemical characterization of contaminants on surfaces. This analytical information is required to reconstruct the accident sce...
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