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Martin, David W.

Publications and source records attributed to Martin, David W..

14 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Development of New Type-B Containers and the 'Alternative Approach' Disposal of High-Activity Sealed Sources - 17385

The DOE/NNSA Office of Radiological Security (ORS) is undertaking two projects to enable the recovery and disposal of high-activity sealed sources. First, ORS has completed the development, certification, and fabrication of a new Type B package to support the recovery and transportation of high-activity sources commonly used in irradiators and cancer treatment devices. A second design is currently undergoing certification. The new containers will enable DOE/NNSA shipment of nearly 100 percent of all commercially used devices containing Cs-137 and Co-60, which are particularly significant from a National security, public health, and safety standpoint. Second, ORS and the Conference of Radiation Control Program Directors (CRCPD) Source Collection and Threat Reduction (SCATR) are piloting the commercial disposal of a high-activity device under the NRC's revised guidance on concentration averaging and encapsulation. The Cs-137 blood irradiator is being proposed for disposal at the U.S. Ecology facility in Richland, WA. The project is intended to serve as a model for commercial disposal of similar Class C sources that for decades have been without a commercial disposal pathway. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Treatment of Bottled Liquid Waste During Remediation of the Hanford 618-10 Burial Ground - 13001

A problematic waste form encountered during remediation of the Hanford Site 618-10 burial ground consists of bottled aqueous waste potentially contaminated with regulated metals. The liquid waste requires stabilization prior to landfill disposal. Prior remediation activities at other Hanford burial grounds resulted in a standard process for sampling and analyzing liquid waste using manual methods. Due to the highly dispersible characteristics of alpha contamination, and the potential for shock sensitive chemicals, a different method for bottle processing was needed for the 618-10 burial ground. Discussions with the United States Department of Energy (DOE) and United States Environmental Protection Agency (EPA) led to development of a modified approach. The modified approach involves treatment of liquid waste in bottles, up to one gallon per bottle, in a tray or box within the excavation of the remediation site. Bottles are placed in the box, covered with soil and fixative, crushed, and mixed with a Portland cement grout. The potential hazards of the liquid waste preclude sampling prior to treatment. Post treatment verification sampling is performed to demonstrate compliance with land disposal restrictions and disposal facility acceptance criteria. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2013

Collaboration and Commitment to Sealed Source Safety, Security, and Disposition - 13627

EnergySolutions, the Division of Radiation Control at the Utah Department of Environmental Quality (UDEQ), the Conference of Radiation Control Program Directors (CRCPD), and the Department of Energy's Global Threat Reduction Initiative (GTRI) are collaborating on a truly innovative effort to expand opportunities for cost-effective sealed source disposal. These entities have developed a first-of-its-kind initiative to dispose of certain sealed sources at the EnergySolutions disposal facility near Clive, Utah, which normally cannot accept sealed sources of any type. This creative and collaborative effort to improve radiation health, safety, and security exemplifies the spirit and commitment represented by the Richard S. Hodes, M.D. Honor Lecture Award, which is presented annually at the Waste Management Symposia by the Southeast Compact Commission to encourage environmental professionals and political leaders to develop innovative approaches to waste management in the United States. The participants in the collaborative initiative are honored to receive special recognition for their efforts thus far. They also recognize that the hard work remains to be done. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2013

Sealed Source Security and Disposition: Progress and Prospects - 13515

Due to their high activity and portability, unsecured or abandoned sealed sources could cause significant health or environmental damage. Further, some of these sources could be used either individually or in aggregate in radiological dispersal devices commonly referred to as 'dirty bombs', resulting in significant social disruption and economic impacts in the billions of dollars. Disposal access for disused sealed sources, however, has been a serious challenge. From 2008 to 2012, sealed source disposal was available to only 14 states; additionally, waste acceptance criteria for sealed sources at the low-level waste disposal facilities in operation both prior to and after 2012 exclude some common yet potentially dangerous sealed sources. Recent developments, however, suggest that significant improvement in addressing this challenge is possible, although challenges remain. These developments include 1) the initiation of operations at the Waste Control Specialists (WCS) commercial low-level radioactive waste (LLRW) disposal facility in Andrews County, Texas; 2) the potential for significant revisions of the U.S. Nuclear Regulatory Commission's (NRC) 1995 'Final Branch Technical Position on Concentration Averaging and Encapsulation' (1995 BTP); and 3) the Utah Department of Environmental Quality's (UDEQ) approval of a license variance for sealed source disposal at the EnergySolutions LLRW disposal facility near Clive, Utah. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Status of Global Threat Reduction Initiative's Activities Underway to Address Major Domestic Radiological Security Challenges - 12105

During their service lives, radioactive sealed sources are used for a wide variety of essential purposes. However, each year, thousands of radioactive sealed sources that pose a potential risk to national security, health, and safety become disused and unwanted in the United States. Due to their concentrated activity and portability, these sources could be used in radiological dispersal devices ('dirty bombs'). For more than a decade, the National Nuclear Security Administration and the U.S. Department of Energy, through the Global Threat Reduction Initiative Offsite Source Recovery Project (GTRI/OSRP), have facilitated the removal and disposition of thousands of disused/unwanted sources worldwide. However, the ability of GTRI/OSRP to continue its work is critically dependent on the ability to transport and appropriately dispose of these sources. On that front, GTRI/OSRP progress includes development of two prototype Type B transport containers and significant efforts toward certification, increased commercial disposal access for risk-significant sealed sources at commercial sites, and cooperation through the International Atomic Energy Agency to increase source repatriation. Disused sealed sources continue to pose a national security concern. The impact of a dirty bomb detonation could be costly both financially and to those exposed to the resulting radiation. However, significant progress has been made since 2008 on each of the challenges identified in the DHS Sealed Source Security Workshop. Not only will there be increased opportunity for commercial disposal of many sizes and types of sealed sources, but also stakeholders are studying front-end solutions to the problem of disused sealed sources, such as financial assurance and recycle. The lack of sealed source transport containers is also likely to be mitigated with the development and certification by NNSA of two new Type B models. Internationally, increased efforts at source repatriation will mitigate the threat posed by disused sealed sources abroad. Sealed sources provide irreplaceable benefits to those who use them or who benefit from their use; now stakeholders are rising to the challenge of ensuring that those benefits are safely and securely realized. (authors)

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1993

Three years of rainfall over the Indian Ocean

Monthly rain falling on the Indian Ocean is mapped for the period 1979 through 1981 by means of observations of the Nimbus-7 Scanning Multichannel Microwave Radiometer. Both stationary and mobile parts were found in the pattern of rain. The stationary part consisted of three zonal and two meridional bands. Only one, the band along and south of the equator, maintained a strong presence through all seasons. A north equatorial counterpart to this south equatorial band also was persistent, but weak. The mobile part of the pattern took the form of a wave. The locus of this wave was an eastward-tilted figure eight, which straddled the equator. The wave moved clockwise along the north loop of the figure eight, counterclockwise along the south loop. The crest of the wave crossed the equator from south to north in May or June and crossed the equator from north to south between August and October. Along its path the equatorial bands were alternately amplified and damped, and the transient bands were activated and suppressed. The effect of the bands and wave was to produce a strong 'monsoon' (annual cycle, summer peak) signature in rain falling over both the northeastern and southwestern reaches of the Indian Ocean.

Martin, David W.↗
NASA NTRS1992

A passive microwave algorithm for tropical oceanic rainfall

This study discusses a rainfall algorithm utilizing six channels of microwave radiance data from the Nimbus-7 Scanning Multifrequency Microwave Radiometer. The algorithm is intended for short-term climate studies over the ocean at low latitudes. To find a set of functional relationships, rain rates are regressed on brightness temperatures for each channel. Next, these functions are integrated over a class of rain-rate distributions to find relations between mean brightness temperatures and mean rain rates. This step accounts for beam filling. Finally, weights are obtained for combining the rain rates from the individual channels. The weights vary with the rain rates, so that the optimum combination of channels is always used. Results are stored in a database grid 1 deg latitude x 1 deg longitude by one month. To test the algorithm, three years (1979-81) of data from the Indian Ocean are processed.

Hinton, Barry B.↗
NASA NTRS1992

Antecedent precipitation index determined from CST estimates of rainfall

This paper deals with an experimental calculation of a satellite-based antecedent precipitation index (API). The index is also derived from daily rain images produced from infrared images using an improved version of GSFC's Convective/Stratiform Technique (CST). API is a measure of soil moisture, and is based on the notion that the amount of moisture in the soil at a given time is related to precipitation at earlier times. Four different CST programs as well as the Geostationary Operational Enviroment Satellite (GOES) Precipitation Index developed by Arkin in 1979 are compared to experimental results, for the Mississippi Valley during the month of July. Rain images are shown for the best CST code and the ARK program. Comparisons are made as to the accuracy and detail of the results for the two codes. This project demonstrates the feasibility of running the CST on a synoptic scale. The Mississippi Valley case is well suited for testing the feasibility of monitoring soil moisture by means of CST. Preliminary comparisons of CST and ARK indicate significant differences in estimates of rain amount and distribution.

Martin, David W.↗
NASA NTRS1991

Application of lightning data to satellite-based rainfall estimation

Information on lightning may improve rain estimates made from infrared images of a geostationary satellite. We address this proposition through a case from the Cooperative Huntsville Meteorological Experiment (COHMEX). During the afternoon and evening of 13 July 1986 waves of showers and thunderstorms developed over and near the lower Tennessee River Valley. For the shower and thunderstorm region within 200 km of the National Weather Service radar at Nashville, Tennessee, we measure cold-cloud area in a sequence of GOES infrared images covering all but the end of the shower and thunderstorm period. From observations of the NASA/Marshall direction-finding network in this small domain, we also count cloud-to-ground lightning flashes and, from scans of the Nashville radar, we calculate volume rain flux. Using a modified version of the Williams and Houze scheme, over an area within roughly 240 km of the radar (the large domain), we identify and track cold cloud systems. For these systems, over the large domain, we measure area and count flashes; over the small domain, we calculate volume rain flux. For a temperature threshold of 235K, peak cloud area over the small domain lags both peak rain flux and peak flash count by about four hours. At a threshold of 226K, the lag is about two hours. Flashes and flux are matched in phase. Over the large domain, nine storm systems occur. These range in size from 300 to 60,000 km(exp 2); in lifetime, from about 2 1/2 h to 6 h or more. Storm system area lags volume rain flux and flash count; nevertheless, it is linked with these variables. In essential respects the associations were the same when clouds were defined by a threshold of 226K. Tentatively, we conclude that flash counts complement infrared images in providing significant additional information on rain flux.

Martin, David W.↗
NASA NTRS1990

Estimates of daily rainfall over the Amazon basin

Five geostationary satellite rain estimation techniques were tested over Amazonia. Individually, the techniques explained 1/4 to 1/3 of the variance of daily gage rainfall. Based in large part on cost, one technique, which involves a nonlinear relation in temperature, was selected to provide a mapping of daily Amazonia rainfall between May 6 and 12, 1987. Accumulated over the 7 days, rainfall by this technique averaged 40 mm. It varied from zero in the southeast to more than 150 mm in the northwest. To the southwest the predominantly convective pattern of the rain image was overlaid by a streakines, implying some baroclinic influence. In maps combining gage observations with satellite estimates, rainfall varied significantly from day to day. Only over the largest scale did a trend emerge: a tendency for rain to withdraw from south to north.

Martin, David W.↗
NASA NTRS1990

Use of microwave satellite data to study variations in rainfall over the Indian Ocean

The University of Wisconsin Space Science and Engineering Center mapped rainfall over the Indian Ocean using a newly developed Scanning Multichannel Microwave Radiometer (SMMR) rain-retrieval algorithm. The short-range objective was to characterize the distribution and variability of Indian Ocean rainfall on seasonal and annual scales. In the long-range, the objective is to clarify differences between land and marine regimes of monsoon rain. Researchers developed a semi-empirical algorithm for retrieving Indian Ocean rainfall. Tools for this development have come from radiative transfer and cloud liquid water models. Where possible, ground truth information from available radars was used in development and testing. SMMR rainfalls were also compared with Indian Ocean gauge rainfalls. Final Indian Ocean maps were produced for months, seasons, and years and interpreted in terms of historical analysis over the sub-continent.

Hinton, Barry B.↗
NASA NTRS1987

Lightning data study in conjunction with geostationary satellite data

During the summer of 1985, cloud-to-ground stroke lightning were collected. Thirty minute samples of lightning were compared with GOES IR fractional cold cloud coverage computed for three temperature thresholds (213, 243, and 273 K) twice daily (morning and evening). It was found that satellite measurements of cold cloud have a relationship to the flashrate and, in a more limited way, to the polarity and numbers of return strokes. Results varied little by location. Lightning, especially positive strokes, was found to be correlated with fractional cloud coverage, especially for clouds at or below 213 K. Other data and correlations are discussed.

Auvine, Brian↗
NASA NTRS1987

Quick look Atlantic Ocean rain maps for gale

A set of quick look maps of Atlantic Ocean rainfall were made. The maps are based entirely on information extracted from geostationary satellite images. The maps and the process by which they were made are briefly described. The major shortcomings of such a project are pointed out. For convenience the maps are presented in rectangular format. Each map covers one day. Rainfall is contoured in units of millimeters. Rainfall was estimated by the Arkin technique.

Martin, David W.↗