Radiation Exposures in the Vicinity
of the Uranium Facility in Apollo Pennsylvania

Table of Contents

Preface

Executive Summary

Chapter 1 The Apollo Site

A. Uranium

B. Other Activities

Chapter 2 Methodology

A. Analysis of Uranium Concentrations in Air and Soil: Methodology

B. Limitations of Annual Air Concentrations Estimates

Soluble and Insoluble Uranium
Non-uniform Emissions
Rain hats and building wake effects
Partitioning of Time-integrated Air and Soil Concentrations

Chapter 3 Stack Monitoring Data

A. Data Quantity and Quality

B. Stack Source Term- Monthly Averaging and Stack Averaging Methods

C. Results

D. Comparison of source terms

E. Compliance of measured concentrations in stack effluents with license requirements

Chapter 4 Air Monitoring, Fallout, and TLD Data 1966-1991

A. Data compilation

B. Partitioning of air concentrations over time

C. External gamma radiation

Chapter 5 The 1997 Apollo Survey and Interpretation of Data

A. The 1997 Soil Data Set

B. Estimating Background uranium Concentration

C. Estimating Deposited Uranium

D. Accounting for removal from soil over time- Fernald plant results

E. Applying Fernald Results for Soil Removal Coefficient to the Apollo Site

F. Excess Uranium Activity in Soil over Time

Chapter 6 Estimate of Time Integrated Concentration of Insoluble Uranium in Air from Soil Data

Chapter 7 Comparison with Predictions from B&W Dispersion Model

Chapter 8 Regulatory Requirements Relating to Radiation Exposures

Chapter 9 Assessment of doses to individual residents

Appendix A Production of Uranium Materials

Appendix B Meteorological Conditions

Appendix C Results of Wind Tunnel Simulations

Appendix D Plaintiff Location and Occupancy Data

Appendix E References

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Executive Summary

We reviewed data and documents pertaining to releases of uranium from the Apollo plant and the consequences of those releases for radiation doses to people living in the vicinity of the plant. Finding the data to be insufficient to draw reliable conclusions, we used two sets of data that were generated specifically for this report - a set of 38 soil samples taken in the vicinity of the Apollo Plant, and a set of wind tunnel experiments.

The soil samples clearly show that enriched uranium was deposited in the soil from the operation of the Apollo plant. We calculated time-integrated air concentrations of uranium from these soil data and provided the results to Dr. M.C. Thorne, who did the most of the dose estimated in consultation with IEER. The doses calculated on the basis of the soil data are a minimum estimate of those that were likely experienced, for at least two reasons. First, the soil data do not reflect emissions of soluble uranium, since the residence time of soluble uranium in the soil is well under one year. Further, dose calculations are based on annual average air concentrations; as such, they would not include exposures to high release events, such as accidents, that any of the plaintiffs might have experienced, if they happened to be in the vicinity of the plant at the time of such events. The paucity of stack data makes it impossible to reconstruct the number and magnitude of such high release events that may have occurred over the duration of plant operation.

Stack data indicate that the AEC criteria for plant operation were exceeded by one of more stacks in numerous years of operation. Further, wind tunnel experiments indicate that building wake effects and the paucity of roof edge monitors make it likely that these monitors did not accurately measure the effect of stack releases at the plant boundary, which in certain directions is defined by the roof edge. In some cases off-site concentrations could have far exceeded the measurements made at the locations of the roof edge monitors, while in other cases offsite air concentrations would have been lower than roof edge monitor locations. Since stack data were collected for only a small fraction of the time during most of the plant's operation and since there were a large number of stacks in operation, it is now impossible to accurately reconstruct the actual pattern of releases and roof edge air concentrations.

We have used plant documents to develop illustrative calculations of possible doses from soluble uranium emissions and from high release events. These illustrative calculations are not to be understood as bounding estimates.

There were also other radionuclides that were present and/or processed at the Apollo plant. Gamma radiation dose rates in unrestricted areas exceeded the 10CFR20 limit at locations in which extended presence of members of the general public was likely, notably the location "Shipping Storage Area E" located inside the Raychord facility.

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