Description of radiological problems at inactive uranium mill sites and formerly utilized MED/AEC sites

During the early years of development of the nuclear program in the United States, more than a hundred sites were used by the Manhattan Engineer District (MED), and the U.S. Atomic Energy Commission (AEC), and/or its uranium suppliers. Many of these sites are no longer used for such activities, but in many cases, the real estate remains contaminated with radioactivity and can be a potential source of exposure to members of the general public. In addition, 22 inactive uranium mill tailings sites exist in the western part of the United States. Radioactive contamination conditions range from slight contamination on the surfaces of buildings and equipment to extensive contamination of the subsoil. The Department of Energy is conducting a program to assure that adequate precautions are taken in the management of these properties to provide the cost-effective protection of public health while permitting further use of land and other resources. Several issues which should be considered in the development of an effective policy for long-term management of such properties are identified

Standards and guidelines pertinent to the development of decommissioning criteria for sites contaminated with radioactive material

A review of existing health and safety standards and guidelines has been undertaken to assist in the development of criteria for the decontamination and decommissioning of property contaminated with radioactive material. During the early years of development of the nuclear program in the United States, a number of sites were used which became contaminated with radioactive material. Many of these sites are no longer useful for nuclear activities, and the U.S. DOE desires to develop criteria for the management of these sites for future uses. Radiation protection standards promulgated by ICRP, NCRP, and ANSI have been considered. Government regulations, from the Code of Federal Regulations and the legal codes of various states, as well as regulatory guidelines with specific application to decommissioning of nuclear facilities also have been reviewed. In addition, recommendations of other scientific organizations such as the National Academy of Sciences/National Research Council Advisory Committee on the Biological Effects of Ionizing Radiations and the United Nations Scientific Committee on the Effects of Atomic Radiation were considered. Finally, a few specific recommendations and discussions from current literature were included. 28 references

Fourth Personnel Dosimetry Intercomparison Study

The fourth Personnel Dosimetry Intercomparison Study was held at the Oak Ridge National Laboratory's Dosimetry Applications Research Facility during March 15-23, 1978. The Health Physics Research Reactor (HPRR) used unshielded, with a 12-cm-thick Lucite shield, a 20-cm-thick concrete shield, or a 5-cm-thick steel and 15-cm-thick concrete shield, and provided four neutron and gamma-ray spectra. Then the dose was calculated based on the HPRR neutron spectra and dose conversion factors which had been determined previously for the four spectra. The results of these personnel dosimetry intercomparison studies reveal that estimates of dose equivalent vary over a wide range. The standard deviation of the mean of participants data for gamma measurements was in the range of 29 to 43%; for neutrons it was 57 to 188%. (PCS

Waste management practices in decommissioning nuclear facilities

Several thousand sites exist in the United States where nuclear activities have been conducted over the past 30 to 40 years. Questions regarding potential public health hazards due to residual radioactivity and radiation fields at abandoned and inactive sites have prompted careful ongoing review of these sites by federal agencies including the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC). In some instances, these reviews are serving to point out poor low-level waste management practices of the past. Many of the sites in question lack adequate documentation on the radiological conditions at the time of release for unrestricted use or were released without appropriate restrictions. Recent investigations have identified residual contamination and radiation levels on some sites which exceed present-day standards and guidelines. The NRC, DOE, and Environmental Protection Agency are all involved in developing decontamination and decommissioning (D and D) procedures and guidelines which will assure that nuclear facilities are decommissioned in a manner that will be acceptable to the nuclear industry, various regulatory agencies, other stakeholders, and the general public

Personnel dosimetry intercomparison studies at the ORNL Health Physics Research Reactor

The Health Physics Research Reactor (HPRR), used unshielded, with a 12-cm-thick Lucite shield or a 13-cm-thick steel shield, provided three neutron and gamma-ray spectra for personnel dosimetry intercomparison studies. The characterisitcs of these fields, such as neutron energy spectrum, intensity, and uniformity, had been measured previously during nuclear accident dosimetry studies. Exposures were made to simulate total exposures likely to be encountered in personnel dosimetry. Neutron dose equivalents of the order of 500 mrem were produced. Dosimeters were mounted on the trunk section of water-filled phantoms, the front edges of which were located three meters from the reactor center. When shields were used they were placed at two meters. Sulfur pellets exposed at a standard location on the reactor during the intercomparison were used to calculate values of tissue kerma for neutrons at the three meter position based on previous measurements. Hurst proportional counter measurements made at the time of the exposures are in good agreement with these results. The gamma component of dose, typically of the order of a few tens of mrad, was measured with LiF thermoluminescent dosimeters (TLD's). Using the fission yield and the calculated leakage of the HPRR, the neutron fluence was calculated for each reactor run. Then the dose was calculated based on the HPRR neutron spectra and the dose conversion factors which had been calculated previously for the three spectra. The results of these personnel dosimetry intercomparison studies reveal that estimates of dose equivalent vary over a wide range. The standard deviation of the mean of participants data was typically in the range of +-30 to +-40%. It is anticipated that this type of dosimetry intercomparison study will be worthwhile on an annual basis until the problems in dosimeter response and interpretation have been identified and solved

Radon and radon daughter measurements at and near the former Middlesex Sampling Plant, Middlesex, New Jersey

The results of the radon and radon daughter measurements made to date (1978) at the Middlesex Sampling Plant in Middlesex, New Jersey, are presented in this report. These measurements were one portion of a more comprehensive radiological survey conducted at this site and the surrounding area from 1976 to 1978. The surveyed property served as a uranium ore sampling plant during the 1940's and early 1950's and as a result contains elevated levels of surface an subsurface contamination. On-site indoor radon daughter and radon concentrations exceeded both the US Surgeon General Guidelines and the Nuclear Regulatory Commission's maximum permissible concentration limits for radon (10 CFR Part 20) in all structures surveyed. Off-site structures showed concentrations of radon and radon daughters at or only slightly above background levels, except for one site where the radon levels were found to be above the 10 CFR Part 20 guidelines. Outdoor radon ad radon daughter concentrations, measured both on and off the site, were well below the guidelines, and the data give no indication of significant radon transport from the site

Two novel mutations in the vasopressin V2 receptor gene in patients with congenital nephrogenic diabetes insipidus

Families with congenital nephrogenic diabetes insipidus were analyzed with regard to mutations in the vasopressin V2 receptor gene. Family 1 shows an X-chromosomal recessive inheritance of the disease over 4 generations. A patient from this family was found to have a T-->A transversion at nucleotide 1095, predictive for a substitution of serine 167 (which is highly conserved among G-protein-coupled receptors), by threonine. Both the mutant and the normal allele were detected in the maternal genome. The patient's healthy brother was homozygous for the normal allele. The patient from family 2 showed a T-->C transition at nucleotide 727, predictive for a substitution of leucine 44 by proline. Analysis of the maternal genome revealed homozygosity for the normal allele. Thus a de novo mutation seems to have occurred. The nature and site of the mutation in family 2 suggest that it is responsible for the patient's disease