Results of some initial space qualification testing on triple junction a-Si and CuInSe2 thin film solar cells

A series of environmental tests were completed on one type of triple junction a-Si and two types of CuInSe2 thin film solar cells. The environmental tests include electron irradiation at energies of 0.7, 1.0, and 2.0 MeV, proton irradiation at energies of 0.115, 0.24, 0.3, 0.5, 1.0, and 3.0 MeV, post-irradiation annealing at temperatures between 20 C and 60 C, long term exposure to air mass zero (AM0) photons, measurement of the cells as a function of temperature and illumination intensity, and contact pull strength tests. As expected, the cells are very resistant to electron and proton irradiation. However, when a selected cell type is exposed to low energy protons designed to penetrate to the junction region, there is evidence of more significant damage. A significant amount of recovery was observed after annealing in several of the cells. However, it is not permanent and durable, but merely a temporary restoration, later nullified with additional irradiation. Contact pull strengths measured on the triple junction a-Si cells averaged 667 grams, and pull strengths measured on the Boeing CuInSe2 cells averaged 880 grams. Significant degradation of all cell types was observed after exposure to a 580 hour photon degradation test, regardless of whether the cells had been unirradiated or irradiated (electrons or protons). Although one cell from one manufacturer lost approximately 60 percent of its power after the photon test, several other cells from this manufacturer did not degrade at all

Solar cell calibration facility validation of balloon flight data: A comparison of shuttle and balloon flight results

The Solar Cell Calibration Facility (SCCF) experiment was designed and built to evaluate the effect of the Earth's upper atmosphere on the calibration of solar cell standards. During execution of the experiment, a collection of carefully selected solar cells was flown on the shuttle, and reflown on a high-altitude balloon, then their outputs were compared. After correction to standard temperature and intensity values of 28 C and an Earth-Sun distance of 1 AU, the solar cell outputs during the two flights were found to be identical. The conclusion is therefore that the high-altitude balloon flights are very good vehicles for calibrating solar cells for use as space flight reference standards

MINOR PARAMETERS NEEDED FOR INDIVIDUAL-DOSE CALCULATIONS: Final Report for Tasks 7.1, 7.2, 8.1, 8.2, 9.1, 9.2, and 9.3

This brief report documents the selection of parameters needed to support individual-dose calculations from 131I released into the environment with gaseous effluents from the Mayak Production Association

FURTHER STUDIES ON UNCERTAINTY, CONFOUNDING, AND VALIDATION OF THE DOSES IN THE TECHA RIVER DOSIMETRY SYSTEM: Concluding Progress Report on the Second Phase of Project 1.1

This is the concluding Progress Report for Project 1.1 of the U.S./Russia Joint Coordinating Committee on Radiation Effects Research (JCCRER). An overwhelming majority of our work this period has been to complete our primary obligation of providing a new version of the Techa River Dosimetry System (TRDS), which we call TRDS-2009D; the D denotes deterministic. This system provides estimates of individual doses to members of the Extended Techa River Cohort (ETRC) and post-natal doses to members of the Techa River Offspring Cohort (TROC). The latter doses were calculated with use of the TRDS-2009D. The doses for the members of the ETRC have been made available to the American and Russian epidemiologists in September for their studies in deriving radiogenic risk factors. Doses for members of the TROC are being provided to European and Russian epidemiologists, as partial input for studies of risk in this population. Two of our original goals for the completion of this nine-year phase of Project 1.1 were not completed. These are completion of TRDS-2009MC, which was to be a Monte Carlo version of TRDS-2009 that could be used for more explicit analysis of the impact of uncertainty in doses on uncertainty in radiogenic risk factors. The second incomplete goal was to be the provision of household specific external doses (rather than village average). This task was far along, but had to be delayed due to the lead investigator’s work on consideration of a revised source term

ASSESSMENT OF VARIOUS TYPES OF UNCERTAINTY IN THE TECHA RIVER DOSIMETRY SYSTEM

Recent developments in evaluation of dose-response models in light of uncertain dose data (Stram and Kopecky 2003; Schafer and Gilbert 2006) have highlighted the importance of different types of uncertainties in the development of individual dose estimates. These include uncertain parameters that may be either shared or unshared within the dosimetric cohort, and also the nature of the type of uncertainty as either classical or Berkson. This report is an initial attempt to identify the nature of the various input parameters and calculational methods incorporated in the Techa River Dosimetry System (based on the TRDS-2000 implementation as a starting point, with additions for recently-developed capabilities). This report reviews the database, equations, and input parameters, and then identifies the author's interpretations of their general nature. It closes with some questions for the users of the data (epidemiologists and biostatisticians), so that the next implantation of the TRDS will provide the most useful information

Preliminary environmental assessments of known geothermal resource areas in the United States

The basic purpose of the Geothermal Overview Project is to identify, summarize, and assess the environmental issues of the top priority KGRAs from among the approximately 40 KGRAs currently identified by the Division of Geothermal Energy, DOE, as having high possibilities for commercial development. The Geothermal Overview Project addresses issues pertaining to air quality, ecosystems quality, noise effects, geological effects, water quality, socioeconomic effects, and health effects. For each KGRA the following functions are accomplished: identification of key issues; inventory of all available data; analysis and assessment of available data; and, identification of what additional information is required for adequate assessments. Studies at the Geysers-Calistoga KGRA in Northern California are used as an example

Risk-based screening analysis of ground water contaminated by radionuclides introduced at the Nevada Test Site (NTS)

The Nevada Test Site (NTS) is located in the southwestern part of Nevada, about 105 km (65 mi) northwest of the city of Las Vegas. Underground tests of nuclear weapons devices have been conducted at the NTS since late 1962 and ground water beneath the NTS has been contaminated with radionuclides produced by these tests. This concern prompted this examination of the potential health risk to these individuals from drinking the contaminated ground water either at a location on the NTS (assuming loss of institutional control after 100 y) or at one offsite (considering groundwater migration). For the purpose of this assessment, a representative mix of the radionuclides of importance and their concentrations in ground water beneath the NTS were identified from measurements of radionuclide concentrations in groundwater samples-of-opportunity collected at the NTS. Transport of radionuclide-contaminated ground water offsite was evaluated using a travel-time-transport approach. At both locations of interest, potential human-health risk was calculated for an individual ingesting radionuclide-contaminated ground water over the course of a 70-y lifetime. Uncertainties about human physiological attributes, as well as about estimates of physical detriment per unit of radioactive material, were quantified and incorporated into the estimates of risk. The maximum potential excess lifetime risk of cancer mortality estimated for an individual at the offsite location ranges from 7 {times} 10{sup {minus}7} to 1 {times} 10{sup {minus}5}, and at the onsite location ranges from 3 {times} 10{sup {minus}3} to 2 {times} 10{sup {minus}2}. Both the offsite and the onsite estimates of risk are dominated by the lifetime doses from tritium. For the assessment of radionuclides in ground water, the critical uncertainty is their concentration today under the entire NTS

Individual Dose Calculations with Use of the Revised Techa River Dosimetry System TRDS-2009D

An updated deterministic version of the Techa River Dosimetry System (TRDS-2009D) has been developed to estimate individual doses from external exposure and intake of radionuclides for residents living on the Techa River contaminated as a result of radioactive releases from the Mayak plutonium facility in 1949–1956. The TRDS-2009D is designed as a flexible system that uses, depending on the input data for an individual, various elements of system databases to provide the dosimetric variables requested by the user. Several phases are included in the computation schedule. The first phase includes calculations with use of a common protocol for all cohort members based on village-average-intake functions and external dose rates; individual data on age, gender and history of residence are included in the first phase. This phase results in dose estimates similar to those obtained with system TRDS-2000 used previously to derive risks of health effects in the Techa River Cohort. The second phase includes refinement of individual internal doses for those persons who have had body-burden measurements or exposure parameters specific to the household where he/she lived on the Techa River. The third phase includes summation of individual doses from environmental exposure and from radiological examinations. The results of TRDS-2009D dose calculations have demonstrated for the ETRC members on average a moderate increase in RBM dose estimates (34%) and a minor increase (5%) in estimates of stomach dose. The calculations for the members of the ETROC indicated similar small changes for stomach, but significant increase in RBM doses (400%). Individual-dose assessments performed with use of TRDS-2009D have been provided to epidemiologists for exploratory risk analysis in the ETRC and ETROC. These data provide an opportunity to evaluate the possible impact on radiogenic risk of such factors as confounding exposure (environmental and medical), changes in the Techa River source-term data and the change of the approach to individual internal dose estimation (90Sr-body burden measurements and family correlations vs. village averages). Our further plan is to upgrade the TRDS-2009D and to complete a stochastic version of the dosimetry system

Pilot study risk assessment for selected problems at the Fernald Environmental Management Project (FEMP)

Two important environmental problems at the USDOE Fernald Environmental Management Project (FEMP) facility in Fernald, Ohio were studied in this human health risk assessment. The problems studied were radon emissions from the K-65 waste silos, and offsite contamination of ground water with uranium. Waste from the processing of pitchblende ore is stored in the K-65 silos at the FEMP. Radium-226 in the waste decays to radon gas which escapes to the outside atmosphere. The concern is for an increase in lung cancer risk for nearby residents associated with radon exposure. Monitoring data and a gaussian plume transport model were used to develop a source term and predict exposure and risk to fenceline residents, residents within 1 and 5 miles of the silos, and residents of Hamilton and Cincinnati, Ohio. Two release scenarios were studied: the routine release of radon from the silos and an accidental loss of one silo dome integrity. Exposure parameters and risk factors were described as distributions. Risks associated with natural background radon concentrations were also estimated

Population Exposure Dose Reconstruction for the Urals Region

This presentation describes the first preliminary results of an ongoing joint Russian-US pilot feasibility study. Many people participated in workshops to determine what Russian and United States scientists could do together in the area of dose reconstruction in the Urals population. Most of the results presented here came from a joint work shop in St. Petersburg, Russia (11-13 July 1995). The Russians at the workshop represented the Urals Research Center for Radiation Medicine (URCRM), the Mayak Industrial Association, and Branch One of the Moscow Biophysics Institute. The US Collaborators were Dr. Anspaugh of LLNL, Dr. Nippier of PNL, and Dr. Bouville of the National Cancer Institute. The objective of the first year of collaboration was to look at the source term and levels of radiation contamination, the historical data available, and the results of previous work carried out by Russian scientists, and to determine a conceptual model for dose reconstruction