Reconstruction of Enriched Uranium Released to Air from the Former Apollo Facility, Apollo, Pennsylvania.

ABSTRACT: The former Apollo facility converted enriched uranium hexafluoride into uranium oxide for shipment to nuclear fuel fabrication plants from 1957 to 1983. This paper describes quantification of the source term from the Apollo facility in terms of quantities of uranium released, particle size, and solubility characteristics. Releases occurred through stacks, rooftop vents, and an incinerator that operated from 1964 to 1969. Incidental and accidental releases are addressed as part of this analysis. Atmospheric releases of uranium from plant operations were estimated from stack sampling and production records. Roof vents, both filtered and unfiltered, were the major emission points from the plant. The total estimated release of uranium activity (including 234U, 235U, and 238U) to the air was 28 GBq. Measurements by others found that the releases were primarily associated with large particles and that their solubility was variable but generally low (Class Y). The release estimates presented here and those findings were incorporated into a sophisticated atmospheric transport model to estimate atmospheric concentrations and soil contamination levels due to the releases and to reconstruct historical doses to individuals that lived in the vicinity of the former Apollo facility.

Development of a Nursing Assignment Tool Using Workload Acuity Scores.

OBJECTIVE: To determine a just and consistent practice for creating nursing assignments. BACKGROUND: Traditional methods of assigning patients to nurses may lead to unbalanced nursing workload. This article describes the ongoing, hospital-wide effort to evaluate and implement a nursing assignment tool based on electronic health record (EHR) functionality and auto-calculated nursing workload scores. METHODS: EHR records of individual patient workload scores from all hospital units were collected from August 2017 to June 2018. A nurse-specific total workload score was summed for each staff. Then, each hospital unit's mean nurse workload score and standard deviation, along with the unit's nurse-to-patient ratio, were used to calculate levels of high, medium, and low nursing workload measurement (NWM). RESULTS: Mean patient-specific workload scores varied greatly across hospital units. Unit-specific nurse-to-patient ratios were factored into NWM scores to create ranges for assignments that were relatively consistent across the institution. CONCLUSION: The use of objective, electronically generated nursing workload scores, combined with traditional nurse-to-patient ratios, provides accurate real-time nurse staffing needs that can inform best practice in staffing. The confirmation of individual patient workload scores and an appreciation for the complexity of EHR vendor rules are necessary for successful implementation. Automation ensures patient safety, staff satisfaction, and optimal resource allocation.

Reconstruction of atmospheric concentrations of enriched uranium from the former Apollo facility, Apollo, Pennsylvania, USA.

The former Apollo facility in western Pennsylvania converted enriched uranium hexafluoride into uranium oxide for shipment to nuclear fuel fabrication plants from 1957 to 1983. Atmospheric releases of uranium from plant operations were estimated from stack sampling and production records. Releases occurred through stacks, rooftop vents, and an incinerator that operated from 1964 to 1969. Roof vents that exhausted workplace air was the major emission source from the plant. Total estimated release of uranium activity (including 234U, 235U, and 238U) to the air was 27.9 GBq. Atmospheric transport modeling was performed using a complex terrain model because the plant was located in an incised river valley. Almost two years of meteorological data were collected from a nearby 10-m tower, along with sounding from a collocated sodar. Light mean wind speed (1.56 m s-1) and predominately stable atmospheric conditions frequently resulted in poor dispersion conditions in the facility environs. Environmental sampling included continuous air monitoring data and depth profiles of uranium in soil that was deposited from airborne releases. Soil measurements exhibited a sharp drop-off in uranium concentrations with distance from the facility, indicating that large non-inhalable particles were emitted to the atmosphere. Large particles (~15-25 µm aerodynamic equivalent diameter) accounted for 17.5% of the total emissions. Soil measurements were used for model calibration and validation, while air measurements were used to evaluate model performance. Air concentrations were generally over-predicted for locations near the facility but showed only a slight positive bias for locations north of the facility. Predicted uranium activity air concentrations from Apollo sources averaged over 34 years were about three times greater than the background gross alpha activity value of 81 µBq m-3 in a ~0.5 km2 region surrounding the Apollo facility. The contribution of Apollo uranium to the gross alpha air concentration would have been negligible several kilometers from the facility.

Application of NCRP air screening factors for evaluating both routine and episodic radionuclide releases to the atmosphere.

Two separate methods were used to identify the most important historic airborne releases of radionuclides at the Idaho National Engineering and Environmental Laboratory (INEEL) with regard to potential human health impact. Both routine and episodic releases were evaluated. Although not specifically intended for an initial screening or ranking evaluation, particularly for episodic releases, the National Council on Radiation Protection and Measurements (NCRP) screening method was shown to be a valid method for providing a measure of the relative importance of both routine and episodic radionuclide releases, based on comparisons with the Radiological Safety Analysis Code (RSAC). For the work at the INEEL, a relative ranking procedure was used to identify the most important releases because a screening criterion (e.g., dose or risk value) against which the potential health impacts of the releases could be measured was not established. In addition, a precedent for a screening-level evaluation of episodic releases is lacking at this time. As a result, a ranking procedure was considered necessary because it was not clear that the NCRP method would provide screening-level dose estimates for episodic releases that could be defensibly compared to a screening criterion. To evaluate the NCRP method at the INEEL, routine operational releases were evaluated and ranked separately from episodic, or acute, releases because different assumptions and approaches were required to assess their potential importance. Based on comparisons with the RSAC method, the NCRP method may slightly underpredict the ingestion dose for episodic releases; however, using the NCRP screening method to identify the relative importance of release events, radionuclides, years, and facilities was shown to be valid and defensible for both routine and episodic releases. Because of the NCRP method's simplicity and relative ease of application, it provides a cost-effective and scientifically defensible way to make decisions and set priorities about decisions and directions in risk assessment.

Risks to the public from historical releases of radionuclides and chemicals at the Rocky Flats Environmental Technology Site.

This paper summarizes the methods and results of estimating risks of cancer incidence resulting from plutonium, carbon tetrachloride, and beryllium releases from operations at the Rocky Flats Environmental Technology Site, near Denver, Colorado, from 1953 through 1989. The key findings show that people who lived near the facility were exposed to plutonium mainly through inhalation during routine operations, from a major fire in 1957, and from plutonium resuspended from contaminated soil from an outdoor drum storage area, called the 903 Area. Results were presented for five exposure scenarios that were location-independent. Individuals described by the laborer scenario received the highest risk of all scenarios considered. Upper bound (95th percentile) incremental lifetime cancer incidence risks for the laborer scenario were in about the 10(-4) range (1 chance in 10,000) for developing cancer from Rocky Flats plutonium releases during a lifetime. At the 5th percentile level, the maximum cancer risk was about 10(-7) (1 chance in 10 million) for developing cancer during a lifetime. Estimated cancer risks at the 95th percentile level are within the range of for acceptable risks established by the US Environmental Protection Agency of 10(-6) to 10(-4). Carbon tetrachloride was found to be the chemical that presented the highest risk to the public. The 5th and 95th percentile risk values for exposure to carbon tetrachloride were 9.2x10(-7) and 2.5x10(-5), respectively.