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PubMed1988

A consumer and media viewpoint.

The future of the nuclear community will not resemble the past. Suddenly gone are the years of blind public trust, cheers for building the bomb that ended a world war, and the unquestioned alliance of patriotism and Pu. Awakened by the radioactivity cloud from Chernobyl and recent revelations of major releases during Hanford's early years, the public is demanding to play a part in its own future in suddenly jam-packed hearings. After four decades, nuclear pioneers should consider that a technology fashioned largely in the vacuum of war-driven secrecy is now being judged--fairly or not--alongside the rather unforgiving measures of present-day politics, economics and morality. The spiral of distrust may continue without a semblance of the following remedies. (1) The press and the public need to become better educated in radiation basics to start making more informed decisions on multi-billion-dollar issues. (2) Because reasoned public discussions of anything nuclear is at an impasse, supporters and critics of nuclear activities should spend less time trying to discredit their opponents and more time trying to understand why they think as they do. (3) The radiation-protection community should welcome scrutiny for one simple reason: no other way exists to regain public trust and respect.

Community Participation↗
PubMed1989

Migration of radionuclides controlled by several different migration mechanisms through a sandy soil layer.

Column experiments have been carried out on the migration of 60Co and 137Cs through a sandy soil layer in order to examine the migration of radionuclides controlled by several different migration mechanisms. Radionuclide concentration distribution between the effluent and the sandy soil layer was measured after 10 L of the solution containing the radionuclides were introduced into the column from the top of the layer at a constant flow rate. Most of the 60Co and 137Cs remained attached to the layer, and a small amount of each radionuclide; at concentrations of 0.3 and 0.1%, respectively; flowed out from the soil layer. The migration of the mobile fraction of these radionuclides is different from that expected of an ideal cation. These results suggest that the mobile fraction of these radionuclides migrates as non-cationic forms which are not adsorbed into the soil matrix by equilibrium ion exchange.

Cesium Radioisotopes↗
PubMed1989

Effects of vegetation, a clay cap and environmental variables on 222Rn fluence rate from reclaimed U mill tailings.

We measured 222Rn fluence rate and several environmental variables on two plots with U mill tailings buried beneath 30 cm of overburden and 20 cm of topsoil. An additional 30 cm of clay covered the tailings on one plot and each plot was subdivided into bare soil and vegetated subplots. We used linear correlation, two-way ANOVA and stepwise multiple regression to analyze the effects of the plot characteristics and the environmental variables on 222Rn fluence rate. The most important effect on 222Rn fluence rates from these plots was the combination of a clay cap and a vegetated surface. The mean annual fluence rate from the plot having both of these characteristics (520 +/- 370 mBq m-2 s-1) was over three times that of the vegetated plot without a clay cap (170 +/- 130 mBq m-2 s-1) and 18 times that of the bare plot with a clay cap (29 +/- 13 mBq m-2 s-1). The interaction effect may have been due to the growth of roots in the moist clay and active transport of dissolved 222Rn to the surface in water. This speculation is supported by the observation that on vegetated plots with a clay cap, moisture in the clay enhanced the fluence rate.

Air Pollutants↗
PubMed1989

Assessment of radiological emissions from Spanish coal power plants: radioactive releases and associated risks.

The radioactivity of coals and ashes from Spanish coal power plants (CPP) was evaluated. This radioactivity is due mainly to 40K and the U and Th series. The samples were measured in secular equilibrium using a NaI(T1) detector. The annual average airborne releases were also evaluated. An atmospheric dispersion model was developed to predict the annual average concentration of radionuclides in air. The risks from inhalation were calculated and compared with those from nuclear power plants (NPP) and natural radioactivity.

Air Pollutants↗
PubMed1990

Effectiveness of three natural biobarriers in reducing root intrusion by four semi-arid plant species.

Plant root depth, relative density, and an Intrusion Index were determined for three grass and one shrub species growing above three different natural biobarriers. High-clay content soil was the least effective barrier. Scoria (volcanic cinder) was most effective in excluding roots of crested wheatgrass and streambank wheatgrass. Root parameters for sagebrush and Great Basin wildrye were least growing over a biobarrier mixture of gravel and cobble.

Plant Development↗
PubMed1991

The radiological accident in Goiânia: the initial remedial actions.

The removal of a 50.9-TBq 137Cs source from a radiation therapy facility in Goiânia gave rise to a radiological accident in September 1987 whose proportions were aggravated by the 16-d interval from the beginning of a series of acts that resulted in the contamination of people and areas, to the moment of identification and seeking of aid. Data gathered from the declarations of persons involved in the accident, matched with the medical assessment and radiation monitoring of areas affected, made it possible to determine procedures for care of victims and for decontaminating operations of these areas. The priorities of these procedures were to provide care to victims and eliminate critical paths by which other persons might be affected by exposure to radiation or contamination. This paper presents (1) remedial actions taken during the first weeks, (2) management problems associated with the accident, and (3) lessons learned from this episode that are of benefit to us and, hopefully, to others.

Accidents↗
PubMed1991

Radium-226 whole-body gamma counting and 222Rn breath analysis: report on a subject exposed to uranium mill tailings.

One of two boys born in September 1949 who played on U mill tailings between age 8 and 12 was diagnosed as having leukemia at age 15.5. The exposed and control subjects were well matched; they were approximately the same age and both were 1.85 m (6' 1") in height and weighed 75.2 kg (165 pounds). The result obtained by gamma spectrometric method for the exposed subject was 0 +/- 17 Bq (0 +/- 470 pCi), while that for the control subject was 4 +/- 15 Bq (100 +/- 400 pCi). The result obtained by the Rn breath method for the exposed subject was 4.4 +/- 0.7 Bq (120 +/- 20 pCi), while that for the control was 5.4 +/- 1.4 Bq (150 +/- 38 pCi). These results suggest that the 226Ra body burden of the exposed subject is within the range of those observed in subjects exposed only through normal food sources, which have a mean 226Ra content of 1.5 Bq (range: 0.4-4.4 Bq) so that no significant mill-tailing intake is indicated. The best estimate of alpha particle dose to the red marrow from 226Ra and its decay products was 0.05 mGy at age 14 and 0.10 mGy at age 38. This dose, when compared to that observed in the dial painters, suggests that the leukemia was not caused by uptake of Ra from the mill tailings.

Adult↗
PubMed1991

A method to automate radiological surveys: the Ultrasonic Ranging and Data System.

The Ultrasonic Ranging and Data System (USRADS) was developed to allow radiation exposure rate data and positional information to be simultaneously collected, stored, and analyzed in a manner more efficient than conventional survey techniques. USRADS is field portable using ultrasonics to locate a field surveyor on a site and radiofrequency to transmit data. Surveyor position (e.g., measurement location within 10 cm) and an integrated instrument measurement are recorded and stored once each second in a microcomputer. Operational experience indicates that the system results in collection of greater quantity and higher quality of radiological data with less effort in data transcription and analysis and only slightly more field effort compared to conventional manual methods.

Data Collection↗
PubMed1991

A radiological evaluation of phosphogypsum.

Phosphogypsum is the by-product resulting from phosphoric acid or phosphate fertilizer production. The phosphate are used in these chemical processes contains the naturally occurring radioactive material U and all its subsequent decay products. During processing, the U generally remains in the phosphoric acid product, while the daughter, 226Ra, tends to be concentrated in the phosphogypsum. Phosphogypsum has physical properties that make it useful as a sub-base for roadways, parking lots, and similar construction. A radiological evaluation, to determine exposures to workers mixing this material with a stabilizing agent (portland cement), was performed at a South Louisiana phosphoric acid chemical plant. Measurements of the 226Ra content of the phosphogypsum showed an average of 1.1 +/- 0.3 Bq g-1 (0.7-1.7 Bq g-1). The average measured gross gamma exposure rate on the phosphogypsum pile corresponded to a dose equivalent rate of 0.368 +/- 0.006 mu Sv h-1 (0.32-0.42 mu Sv h-1). Radon daughter concentrations measured on top of the phosphogypsum pile ranged from 0.0006 to 0.001 working levels. An analysis of the airborne 226Ra concentrations showed only background levels.

Bismuth↗
PubMed1991

Radium-226 dose to a boy from playing on mill tailings.

Two boys born in September 1949 played on uranium mill tailings from about ages 8 to 12. One of these boys was diagnosed as having leukemia at age 15.5. The 226Ra body burden of the survivor was measured at age 38. The whole-body 226Ra content measured by counting in vivo was 0 +/- 17 Bq and independently by Rn breath analysis as 4.3 +/- 2.1 Bq. At the same time, a control subject with no known exposure to 226Ra, matched in age, height, and weight, was also measured. The whole-body content was estimated as 4 +/- 15 Bq and independently by Rn breath analysis as 5.5 +/- 3.7 Bq. The body burden of the control subject was not significantly different from that of the exposed person. The radiation dose to the marrow-free skeleton assuming a constant 226Ra:Ca ratio since birth was 0.49 and 1.33 mGy at ages 14 and 38, respectively. The radiation dose to the marrow-free skeleton assuming 226Ra intake only between ages 8 to 12 was 1.4 and 2.8 mGy at ages 14 and 38, respectively. The best estimate is the mean of these two estimates: 0.9 and 2.1 mGy at ages 14 and 38, respectively. The alpha-particle dose to the red marrow from 226Ra and its decay products was 0.05 mGy at age 14 and 0.10 mGy at age 38. Since no excess was found for the radium dial painters whose doses were much higher, the induction of leukemia by doses of this magnitude would seem quite unlikely.

Body Burden↗
PubMed1992

Discovery of a 137Cs hot particle in municipal wastewater treatment sludge.

Analysis of primary treatment sludge from a municipal wastewater treatment plant revealed elevated 137Cs concentrations in one sample. This elevated activity was associated with a radioactive particle that, when isolated and quantified, was found to contain 1.82 kBq of 137Cs. Additional analysis indicated an absence of alpha activity, and energetic beta radiation, if present, was less than the 137Cs activity. The particle was approximately 50 microns in diameter, appeared not to be an aggregate, and was nonmetallic.

Cesium Radioisotopes↗
PubMed1992

Determining the probability of radioactive materials on properties in Monticello, Utah.

The former uranium mill site at Monticello, UT, is a surplus facility subject to cleanup under the Surplus Facilities Management Program. Surrounding properties contaminated with mill site material are also subject to cleanup and are referred to as Monticello Vicinity Properties. The objective of this study was to determine the probability that a vicinity property not addressed under the Monticello Vicinity Properties project could contain Monticello mill-related residual radioactive material in excess of Department of Energy guidelines. The study was conducted in a short time frame to protect public health. Statistical methods were used to select 48 random properties for radiological screening surveys. Results of this study may be used to predict the potential number of unassessed properties (results suggest approximately 20%) that contain radioactive contamination that exceeds Department of Energy guidelines and will require remedial action.

Environmental Exposure↗
PubMed1993

The scientific base for the disposal of spent nuclear fuel.

The main objectives of the Swedish expert seminar on spent nuclear fuel disposal were to identify those safety questions for which there is, or will be, a definitive answer, and to establish the degree of uncertainty surrounding those questions which still cannot be satisfactorily answered. The opinion was that the geological environment of the repository can be defined and its behavior predicted with much confidence, assuming the existing environment remains stable. Thus in the short term (a few hundred to thousands of years), the situation is favorable for safe disposal of spent fuel. In the longer term perspective, it was considered necessary to further investigate the evidence of the geologically recent past to predict future changes.

Nuclear Energy↗
PubMed1993

Verification of aquatic dilution factors for liquid effluents released from a nuclear power plant.

Dilution factors for liquid effluents released from the Fermi 2 Power Plant into Lake Erie were verified using updated liquid effluent release data, and currently available aquatic dispersion models. A near-field dilution factor of 5 currently used by Fermi 2 appears to be a reasonable assumption as supported by two models and site-specific data. Previously assumed dilution factors for shoreline points outside the near field are of the same order of magnitude as those calculated by this study. The dilution factor of 77, currently used by Fermi 2, at the Monroe water intake point is very conservative when compared with values calculated by this study. More accurate values could be generated by tracer studies as recommended by Regulatory Guide 1.113. Such studies can predict plume behavior and are more accurate than aquatic models. These new values would probably be less conservative than those currently in use, and their use would make it less likely that Fermi 2 will reach technical specification limits for liquid effluent dose.

Nuclear Energy↗
PubMed1993

Evaluation of the beta energy spectrum from a distributed uranium mill tailings source.

The beta energy spectra from uranium mill tailings, 90Sr with different absorber thicknesses, and a uranium metal slab were measured and compared to select an appropriate beta source for calibrating a personal dosimeter to measure shallow dose equivalent when exposed to uranium mill tailings. The measured beta energy spectrum from the 90Sr source, with a 111 mg cm-2 cover thickness, was selected as a possible calibration source for a personnel dosimeter. The dose equivalent rate to the skin at 1 cm from a distributed tailings source of infinite thickness, with a 226Ra activity of 56 Bq g-1 (1.5 x 10(3) pCi g-1), was measured to be 0.024 mSv h-1 (2.4 mrem h-1).

Beta Particles↗
PubMed1994

Modeling to optimize operational practices to limit shallow dose and dose to the lens at the Weldon Spring Site Remedial Action Project.

The Weldon Spring Site Remedial Action Project (WSSRAP) began remediation of its chemical plant buildings in June 1992. The chemical plant was used by the Atomic Energy Commission in the 1950's and 1960's to process uranium ore and natural thorium. Many remaining equipment surfaces were highly contaminated with uranium and thorium product residues, which are relatively weak gamma emitters, but are strong beta emitters that deposit the majority of their energy within the first centimeter of tissue. An essential part of the remediation, therefore, is to control the dose to the skin, extremities, and the lens of the eye from the broad range of betas emitted by uranium and thorium decay series radionuclides. The WSSRAP planned to quantitatively record the dose to the skin, extremities, and the lens of the eye, when warranted, through selection and use of appropriate passive dosimeters. That would not, however, constitute control. A direct-reading instrument was needed that could be used by field technicians to anticipate and prevent work methods and situations that would otherwise result in the unnecessary commitment of dose. However, the interpretation of real-time instrument readings produced by a broad spectrum of beta energies is typically challenging at best, particularly when the shallow dose rate and the lens dose rate are both of interest. The purpose of this effort was, therefore, to (1) select a direct-reading instrument for use in the buildings that could be used to provide rule-of-thumb action levels for field technicians, which, if exceeded, would warrant worker protective measures; (2) determine the approximate conversions between the instrument readings and the shallow (including extremity) dose rate and lens of the eye dose rate; and (3) specify protective measures and dosimetry for the lens of the eye, if warranted. Methods described in the literature are used to estimate action levels for direct instrument readings and to demonstrate that lens dosimetry and special protective measures for the lens of the eye are not necessary at the WSSRAP.

Humans↗
PubMed1995

Steady-state response of a charcoal bed to radon in flowing air with water vapor.

Previously we have developed a mathematical model of radon adsorption in active air with water vapor on small U.S. Environmental Protection Agency charcoal canisters that are used for environmental measurements of radon. The purpose of this paper is to extend this mathematical model to describe the adsorption of radon by large charcoal beds with radon-laden air flowing through them. The resulting model equations are solved analytically to predict the steady-state adsorption of radon by such beds.

Adsorption↗
PubMed1997

Testing shields in the Argonne National Laboratory fuel conditioning facility support areas.

Testing has been completed for two lightly shielded areas that support operations in the Fuel Conditioning Facility at the Argonne National Laboratory site at the Idaho National Engineering Laboratory. Operational requirements dictated the use of a radiography source containing 0.44 TBq (12 Ci) of 192Ir to challenge reinforced concrete and steel shields that surround a decontamination, maintenance, and repair area for contaminated equipment used in hot cell operations. A more intense source containing 0.89 TBq (24 Ci) of 192Ir was used to test lead shot and steel shields around tanks in a radioactive liquid waste system and the boundaries of the room that contained it. Measurement procedures were developed to find design flaws and construction deficiencies while minimizing radiation exposure to test participants. While the shields are adequate to limit gamma ray deep dose equivalents to 10 mSv y(-1) (1 rem y(-1)) or less to facility personnel, several modifications were necessary to assure that the attenuation is adequate to keep dose rates less than 5 microSv h(-1) (0.5 mrem h(-1)) in normally occupied areas.

Decontamination↗

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