Studies of some parameters affecting radiation doses received from consumption of water derived from the Columbia River downstream of the Hanford production reactors were performed. Included were measurement of radionuclides in (1) water entering and leaving the water treatment plants at Richland and Pasco, Washington; (2) sanitary (municipal) water at a number of points in Richland; and (3) coffee brewed from sanitary water.The removal efficiencies for the alum-floc water treatment plants studied ranged from 80 % for rare-earth nuclides to 10 % for Cr-5 1.The relative concentration of radionuclides (principally Na-24, As-76, Sb-122, Np-239) found within the Richland distribution system was used to estimate the average dose to residents consuming the water. Average GI tract doses calculated for persons residing at each of six locations within the city were 1/3-1/2 of those calculated for consumption of water leaving the treatment plant.The average dose received, calculated by weighing these six individual doses by the population distribution, yielded 45% of that calculated for consumption of water leaving the treatment plant.Since coffee represents a major liquid intake mode for adults, the volume of coffee consumed and the potential removal of radionuclides during coffee brewing was studied. The average drinkable volume of coffee per cup was 200 ml. The concentrations of radionuclides in the water and coffee brewed from it were not significantly different for those radionuclides and hence those doses were not significantly contributing the most to the GI tract dose, reduced.

The Hanford Environmental Dose Reconstruction (HEDR) Project was conducted to estimate the radiation dose that individuals could have received as a result of emissions to the air and water from Hanford Site operations since 1944. The largest doses were to the human thyroid gland from 131I released into the atmosphere from Hanford facilities in the 1945-1947 time period. In support of the dose reconstruction effort, a database of historical environmental radioactivity measurements was constructed. This database includes measurements of total radioactivity for vegetation samples collected from 1945-1948 and counted using a Geiger-Mueller (GM) detector system. Because the factors used at that time to convert the GM counts to 131I activity did not take all parameters into account, and because some parameter values were inaccurate, more accurate conversion factors were developed as part of the HEDR Project. These factors can be used to estimate the actual historical activity levels. This paper summarizes the Monte Carlo uncertainty and sensitivity analysis methods used to assess the uncertainty of the newly reconstructed historical vegetation 131I activities and to identify the parameters that contributed the most uncertainty to these reconstructed activities. Based on the study of two vegetation (sagebrush) samples collected in the mid-1940's, it appears that the true 131I activity of the historical vegetation samples should be within a factor of three of the reconstructed activity. Also, the uncertainty in the parameter Icf (the fraction of the background-corrected GM measurement of a vegetation sample that resulted from 131I) was found to contribute the most uncertainty to the reconstructed 131I activities when the uncertainty in Icf was large.

On 26 March 1963 at approx. 0000 hours a nuclear excursion occurred in a shielded vault designed for critical assembly experiments. The excursion was estimated at 4 x lo1' fissions, and was followed by oxidation of the enriched uranium metal in the assembly. The fire was observed via closed circuit TV; later entry established that burning was limited to the assembly. Nearby combustibles did not burn or scorch.Disaster plans were immediately implemented to determine: (1) radiation exposures to personnel directly involved, (2) the possibility of recurring criticality and (3) the extent of release of radioactive materials to the Laboratory and to the off-site environment.Air and surface contamination levels were determined in the building housing the vault and at other points within the Laboratory perimeter. Air, vegetation, and soil samples, obtained within hours following the excursion, were analyzed for fission product and alpha activity fallout. Results indicated the release of small amounts of short-lived, high-yield gaseous fission products and their daughters. No detectable alpha activity was released to the environment.The maximum exposure to any of the four persons in the building at the time was 120 mrems penetrating gamma radiation. All neutron exposures were less than detectable limits, i.e. 50-mrem fast neutrons and 1-mrem thermal neutrons. Urinalyses, nasal wipes and thyroid scans were all negative, indicating no internal exposure.An air sample taken from within the vault 57 hr after the excursion showed levels of -2 x 1W6 pc/cm3 of short-lived fission products. Radioactive decay and changing the vault air reduced these levels to below MPC values. The air exhausted from the vault was filtered and scrubbed with caustic before release to the atmosphere.The initial vault entry was made to size up and-if necessary-to eliminate t t e possibility of a further excursion. The gross amounts of all fissile material were removed before decontamination operations were begun. The building, exclusive of the vault, was reoccupied 6 days after the incident.This incident reaffirms for us the value of carefully designed vault facilities for critical assembly work.

Most published guides for environmental radiological surveillance emphasize the collection and analysis of specific media (e.g. air, water, milk, direct radiation) without indicating the absolute or relative importance of the media sampled or of the radio analyses performed. To determine the relative importance of medium/nuclide combinations in environmental surveillance, the experience at major DOE sites and at operating nuclear power plants was reviewed. Typical release rates for nuclide groupings (tritium, noble gases, radioiodine, mixed fission or activation products, and transuranics) in those effluent streams were obtained from the literature. Using these release rates, followed through various environmental pathways, radiation doses were calculated for individuals in the local environs of each type of site. Following these calculations, each medium was ranked for a given nuclide/effluent pathway combination providing the relative importance of sampling specific environmental media with emphasis on the radiation dose to a critical population group. Finally, the results of these environmental pathway studies are presented in tabular form to provide ready reference for environmental surveillance program design or evaluation.