Savannah River Plant/Savannah River Laboratory radiation exposure report

The protection of worker health and safety is of paramount concern at the Savannah River Site. Since the site is one of the largest nuclear sites in the nation, radiation safety is a key element in the protection program. This report is a compendium of the results in 1988 of the programs at the Savannah River Plant and the Savannah River Laboratory to protect the radiological health of employees. By any measure, the radiation protection performance at this site in 1988 was the best since the beginning of operations. This accomplishment was made possible by the commitment and support at all levels of the organizations to reduce radiation exposures to ALARA (As Low As Reasonably Achievable). The report provides detailed information about the radiation doses received by departments and work groups within these organizations. It also includes exposure data for recent years to allow Plant and Laboratory units to track the effectiveness of their ALARA efforts. Many of the successful practices and methods that reduced radiation exposure are described. A new goal for personnel contamination cases has been established for 1989. Only through continual and innovative efforts to minimize exposures can the goals be met. The radiation protection goals for 1989 and previous years are included in the report. 27 figs., 58 tabs

Comparison of unsaturated flow and transport models with volume and nitrate measurements from a pilot-scale, in-situ lysimeter with different geometry low level radioactive waste designs

Results from a large-scale field lysimeter experiment containing three thirty-ton monoliths formed from actual decontaminated nuclear waste have been used to validate flow and transport models. The models used are a two-dimensional, finite difference transport and diffusion model. The best match of nitrate concentrations calculated to be released from the monoliths with values observed from the lysimeter occurred with monolith diffusivities in the range of 5 {times} 10{sup -9} to 2 {times} 10{sup -8} cm{sup 2}/sec and dispersivities ranging from 15 to 65 cm. The validated models have been used to predict the performance of a low-level waste disposal facility at the Savannah River Site. 4 refs., 9 figs

A design of experiment study of plasma sprayed alumina-titania coatings

An experimental study of the plasma spraying of alumina-titania powder is presented in this paper. This powder system is being used to fabricate heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Coating experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coating. The coatings were characterized by hardness and electrical tests, image analysis, and optical metallography. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. The attributes of the coatings are correlated with the changes in operating parameters

Quenching and annealing effects on the specific heat of YBa[sub 2]Cu[sub 3]O[sub 7[minus][delta]]

Effect of heat treatments and quenching with no change in oxygen content was studied for a polycrystalline sample of YBCO. Quenching the sample changes the specific heat and resistivity, showing that nonsuperconducting regions, some of which are not associated with Cu[sup 2+] moments, can be created in YBCO by heat treatment alone

Persistence of copper-based nanoparticle-containing foliar sprays in Lactuca sativa (lettuce) characterized by spICP-MS

Copper oxide and hydroxide nanoparticles (Cu-NPs) are components of some commercial pesticides. When these Cu-NPs dissolve in the environment, their size distribution, efficacy, and toxicity are altered. Since acute toxicity screens typically involve pristine NPs, quantification of the transformation of their size distribution in edible leaf vegetables is necessary for accurate consumer risk assessment. Single particle ICP-MS was used to investigate the persistence of three forms of Cu-NPs following foliar application to live lettuce (Lactuca sativa): CuO NP, Cu(OH)2 NP, and Kocide 3000®. A methanol-based digestion method was used to minimize Cu-NP dissolution during extraction from the leaf tissues. After dosing, the NPs associated with the leaf tissues were characterized over a 9-day period to monitor persistence. Nanoparticle counts and total copper mass concentrations remained constant, though the particle size distributions shifted down over time.Washing the leaves in tap water resulted in removal of total copper while the number of Cu-NPs remaining depended on the form applied. This work indicates that washing of lettuce preferentially removed dissolved Cu over Cu-NPs, and that the amount of residual Cu- NPs remaining is low when applied at the recommended rates for Kocide 3000®.publishe