International Nuclear Information System (INIS)

... chemical radiation effects decomposition extraction columns gamma radiation

International Nuclear Information System (INIS)

... electrophoresis fission products gamma radiation gamma spectra half-life

International Nuclear Information System (INIS)

The application of robotics for repair, refurbishing or dismantling of nuclear installations implies eventually severe radiation resistance requirements on embarked components and subsystems. This is particularly critical when optical sensing is considered. Optoelectronic components and optical fibers are indeed quite sensitive to radiation, and without special design are rapidly out-of-operation in such an environment. This paper reports the results of a series of #gamma# irradiation experiments on such devices, and identify their behavior under radiation. Test results show that carefully selected optical fibers can keep their radiation induced attenuation lower than 0.3 dB/m even up to a total dose of 10 MGy. Temperature annealing can even lower this attenuation down to 0.1 dB/m. On the other hand, commercially available light emitting diodes and photodiodes ...

Energy Technology Data Exchange (ETDEWEB)

Various nylons including nylon 6, nylon 66, nylon 610 and nylon 12 in the forms of fiber and film were irradiated with the gamma-ray from Co-60 at the dose rate of 0.12 Mrad/hr in the atmosphere of oxygen at 7 kg/cm/sup 2/ and at the room temperature. The irradiation in vacuum on the same specimens was performed at 0.5 Mrad/hr. The tensile properties and the gel fraction of the irradiated nylon samples were measured, and the radiation resistance of the nylons against the irradiation at low dose rate was estimated. From the experimental results, it became clear that in the case of irradiation in vacuum, all the nylons were durable to the irradiation of 250 Mrad or more, and nylon 6 was more durable than nylon 12, and in the case of irradiation in pressurized oxygen, the radiation resistance of the nylons decreased to one-tenth as compared with that in vacuum, and contrary to that in vacuum, nylon 12 was superior to nylon 6, ...

International Nuclear Information System (INIS)

Fusion device produces high-level neutrons and #gamma#-rays, which would hazard the safety of the public and workers if the doses would be higher than the regulatory limits because of leakage from the bio-shielding and skyshine. It is essential to monitor the radiation doses in the workshop and the enumerative around fusion devices. A radiation monitoring system (RMS) for full (near and far) areas around a nuclear fusion device has been designed and developed, which can achieve the monitoring and controlling of radiation doses in the workshop area by using the Controller Area Network (CAN), in the institution area by using the Bluetooth Ad hoc network based on a new tree topology formation and routing protocol and in a long range environment by using the General Packet Radio Service (GPRS) network. (authors)

International Nuclear Information System (INIS)

The diagnostic designs for the Laser Megajoule (LMJ) will require components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiations, and, in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced today on existing facilities. The lessons learned about the vulnerabilities of present diagnostic parts fielded mainly on OMEGA for many years, have been very useful guide for the design of future LMJ diagnostics. The present and future LMJ diagnostic designs including this vulnerability approach and their main mitigation techniques will be presented together with the main characteristics of the LMJ facility that provide for diagnostic protection.

International Nuclear Information System (INIS)

... EFFECT OF GAMMA RADIATION AND BAG PACKAGING MATERIALS ON

Energy Technology Data Exchange (ETDEWEB)

Three possibilities to observe the Higgs-top interaction at future {gamma}{gamma}-colliders are discussed: (a) associated Higss production via the {gamma}{gamma}{yields}tanti tH reaction, (b) Higgs obliged radiative correction to the {gamma}{gamma}{yields}tanti t channel, (c) Higgs resonance production via {gamma}{gamma}{yields}H{yields}ZZ. The results obtained show windows of the Higss mass where the Yukawa interaction of the Higss with the top quark can be studied at {gamma}{gamma}-colliders. (orig.).

International Nuclear Information System (INIS)

... beam monitoring betatrons delay circuits errors fluctuations gamma radiation

International Nuclear Information System (INIS)

... electron spin resonance gamma radiation lipids lyophilization lysozyme radicals

Energy Technology Data Exchange (ETDEWEB)

In 1998, research began at Idaho National Engineering and Environmental Laboratory to investigate the application of {sup 6}Li and {sup 7}Li isotopes to the measurement of neutron and gamma radiation. Various size pairs of {sup 6}Li and {sup 7}Li based detectors were exposed to mixed neutron and gamma radiation. Experiments demonstrated that these detectors could be used to measure low level neutron radiation in the presence of high level gamma radiation. (author)

International Nuclear Information System (INIS)

Short communication.

International Nuclear Information System (INIS)

Portuguese Sep-Oct 1996 p. 571 Brazil Campos, Patricia Sao Paulo

International Nuclear Information System (INIS)

The main points of quality control methods and technique of environmental radiological baseline study of Guangdong Daya Bay Nuclear Power Station are reported. Results of intercalibration of international and inland laboratories are given. The random chosen samples are checked and compared with two measurement methods. The data obtained in Daya Bay environment are put to the correlation statistics test using the linear regression analysis method between the correlative items such as "4"0K activity by gamma spectrum measurement and potassium content by chemical analysis, total #alpha#(#beta#) activity and nuclide content, as well as environmental gamma radiation dose rate and TLD accumulation dose. The data of Daya Bay environmental radioactivity baseline level show good concordance and reliability.

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... alpha particles beta particles gamma radiation lead hot cells bricks shielding

International Nuclear Information System (INIS)

... v. 33(4). beta-minus decay de-excitation delayed gamma radiation iron 64

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Short communication.

International Nuclear Information System (INIS)

recycling of waste polypropylene (WPP) and waste rubber (WR) originated from rejected worn-out tires present very important problem due to their huge amount and their negative impact on environment. many communities in the world are struggling with this problem of how to manage waste disposal, in order to eliminate or reduce waste rubber from the environment and to reduce costs of some rubber and polypropylene articles. trials to reuse waste rubber and waste polypropylene, have encountered some difficulties.such two substrate polymers differ from each other in nature, since waste polypropylene is thermoplastic while waste rubber exists in thermosetting state. accordingly, the study and use of their mixtures should be very interesting.the aim of this work is to modify the physical and chemical properties of WR and WPP each in the form of powder (120,80 mech size), through a trial to graft some vinyl comonomers onto their surfaces using ...

International Nuclear Information System (INIS)

Described and discussed in this paper are radiation processes and their advantages over the conventional techniques. Radiation sterilization of medical products, food irradiation, wood plastic composites, and radiation treatment of sewage and waste waters are presented. The Philippine experience in using these technologies, its problems and barriers are also given. (ELC).

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... de-excitation excited states gamma radiation inelastic scattering mev range

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... radioisotopes coincidence methods energy-level transitions gamma radiation

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... data deuteron beams energy dependence errors gamma radiation lead 203

Energy Technology Data Exchange (ETDEWEB)

The Albedo Theory was applied in order to develop an one-group algorithm for coupled neutron-gamma shielding calculations. The configuration analyzed consists of multilayered plane systems, where a incident neutron current generates gamma radiation through neutron-gamma reactions. The results obtained by Albedo Method and ANISN code have shown excellent agreement. (author)

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No abstract prepared

International Nuclear Information System (INIS)

There are many differences between industrial CT and industrial radiography, such as imaging principle, inspection time, radiation dose and the requirements for operators etc. The national standards for radiation protection of industrial detection are not applicable to the requirements of protection and safety for #gamma#-ray industrial CT to some extent now. In order to standardize the production and use for #gamma#-ray industrial CT, protect the safety of operators and the public, and to promote the popularization and application of #gamma#-ray industrial CT, it is significant to establish the national standards for radiation protection of #gamma#-ray industrial CT as soon as possible. The purpose of this paper is to introduce the contents of this standard, and specify some important terms. Then there is a brief discussion on the existing ...

Energy Technology Data Exchange (ETDEWEB)

The space environment consists of a varying field of radiation particles including high-energy ions, with spacecraft shielding material providing the only major protection to astronauts from harmful exposure. Unlike low-linear energy transfer (LET) {gamma} or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure, since the dose delivered by the charged particle increases sharply as the particle approaches the end of its range, a position known as the Bragg peak. The Bragg curve does not necessarily represent the biological damage along the particle traversal, and the 'biological Bragg curve' is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. Here we used a unique irradiation geometry to measure the biological response across the Bragg curve in human fibroblasts ...

International Nuclear Information System (INIS)

A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.

International Nuclear Information System (INIS)

The results of theoretical and experimental investigations, describing the effect of ionizing radiation on wood and its main components and methods for production of wood-plastic composites by means of radiation-induced chemical modification are generalized. Domestic and foreign experience in their production is systematized; physico-mechanical characteristics of new material, simulation and calculation of irradiating devices, as well as calculation and experimental study of #gamma#-radiation attenuation both by wood material and by wood of different species are given. Gamma sources ("6"0Co isotope, a hot loop of a nuclear reactor) as well as electron accelerators are considered as ionizing radiation sources.

International Nuclear Information System (INIS)

Full text: Measurement of K_#beta# to K_#alpha# x-ray intensity ratios are important not only in the field of atomic physics, radiation physics and medical physics, but also to test the validity of assumptions made in the theoretical prediction. The intensity ratios can also give information on the effect of physical and chemical environment of the element in the compound. Many investigators have adopted a single and double reflection geometries to measure the K_#beta# to K_#alpha# x ray intensity ratios to understand the effect of physical and chemical environment on x-ray fluorescence. The targets are excited by a radioactive source of having activity of the order 100 MBq. in order to carry out accurate measurement K_#beta# to K_#alpha# x-ray intensity ratios, we have develop 2#pi# geometrical configuration method : placing a target right on the surface of the detector facing the target to measure the K shell fluorescence ...

Energy Technology Data Exchange (ETDEWEB)

To study CdZnTe as a high energy resolution gamma ray detector with a novel new design, and to build a detector array from the new detector design

Energy Technology Data Exchange (ETDEWEB)

The O({alpha}) electroweak radiative corrections to {gamma}{gamma}{yields}WW{yields}4f within the electroweak standard model are calculated in double-pole approximation (DPA). Virtual corrections are treated in DPA, leading to a classification into factorizable and non-factorizable contributions, and real-photonic corrections are based on complete lowest-order matrix elements for {gamma}{gamma}{yields}4f+{gamma}. Soft and collinear singularities appearing in the virtual and real corrections are combined alternatively in two different ways, namely by using the dipole subtraction method or by applying phase-space slicing. The radiative corrections are implemented in a Monte Carlo generator called Coffer {gamma}{gamma} - the computer code can be obtained from the authors upon request - which optionally includes anomalous triple and quartic gauge-boson couplings in ...

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Inactivation of aflatoxin B1 was studied by using gamma radiation and hydrogen peroxide. A 100-krad dose of gamma radiation was sufficient to inactivate 50 micrograms of aflatoxin B1 in the presence of 5% hydrogen peroxide, and 400 krad was required for total degradation of 100 micrograms of aflatoxin in the same system. Degradation of aflatoxin B1 was confirmed by high-pressure liquid chromatographic and thin-layer chromatographic analysis. Ames microsomal mutagenicity test showed loss of aflatoxin activity. This method of detoxification also reduces the toxin levels effectively in artificially contaminated groundnuts.

Energy Technology Data Exchange (ETDEWEB)

The use of gamma radiation to obtain wood-polymer composites is one of the applications of radiation that presents the most commercial interest. The process, denominated radiopolymerization, comprises the impregnation of monomers into the completely dried wood followed by exposure to gamma radiation to induce polymerization of the impregnated monomers. I this context, the present work aimed the application of this process to seven kinds of wood existing in the brazilian forests. The considered monomer is styrene and the gamma source is Cobalt-60. The obtained wood-polystyrene composites were found to have stronger static bending strength. (author)

International Nuclear Information System (INIS)

(Jan 1974). United States Ashraf, M. Anwar, M. Siddiqui, QH Atomic Energy

International Nuclear Information System (INIS)

Portuguese 1995 1 p. Brazil Lancas, Fernando M. Vilegas, Janete HY Campos,

Energy Technology Data Exchange (ETDEWEB)

Four general topics are covered in respect to the natural space radiation environment: (1) particles trapped by the earth`s magnetic field, (2) cosmic rays, (3) radiation environment inside a spacecraft, (4) laboratory radiation sources. The interaction of radiation with materials is described by ionization effects and displacement effects. Total-dose effects on MOS devices is discussed with respect to: measurement techniques, electron-hole yield, hole transport, oxide traps, interface traps, border traps, device properties, case studies and special concerns for commercial devices. Other device types considered for total-dose effects are SOI devices and nitrided oxide devices. Lastly, single event phenomena are discussed with respect to charge collection mechanisms and hard errors. (GHH)

Energy Technology Data Exchange (ETDEWEB)

A brief overview if provided of selected reports presented at the International Symposium on Molecular Mechanisms of Radiation- and Chemical Carcinogen-Induced Cell Transformation held at Mackinac Island, Michigan on September 19-23, 1993.

International Nuclear Information System (INIS)

Terminal-differential algorithm for identification of local nonhomogeneities in items under control is developed on the basis of measurements of X-ray or gamma-radiation weakening. The algorithm may be applied by developing radiation schemes of nondestructive control, identifying inadmissible inclusions in the object under study

Energy Technology Data Exchange (ETDEWEB)

In scattering of channeled particles by point defects and in emission of gamma rays in the spontaneous-radiation spectral region conditions are attained where the momentum transferred to the defect is taken up by the crystal as a whole. This leads to coherent and interference effects in the radiation from the crystal defects. When the longitudinal momentum transferred is zero, an induced radiation effect appears in the transitions between the states of transverse motion.

Energy Technology Data Exchange (ETDEWEB)

A considerable fraction of radioactivity entering the environment from different nuclear events is associated with particles. The impact of these events can only be fully assessed where there is some knowledge about the mobility of particle bound radionuclides entering the environment. The behavior of particulate radionuclides is dependent on several factors, including the physical, chemical and redox state of the environment, the characteristics of the particles (e.g., the chemical composition, crystallinity and particle size) and on the oxidative state of radionuclides contained in the particles. Six plutonium-containing particles stemming from Runit Island soil (Marshall Islands) were characterized using non-destructive analytical and microanalytical methods. By determining the activity of {sup 239,240}Pu and {sup 241}Am isotopes from their gamma peaks structural information related to Pu matrix was ...

Energy Technology Data Exchange (ETDEWEB)

The technology for performance testing and improvement of materials which are durable at space environment is a military related technology and veiled and securely regulated in advanced countries such as US and Russia. This core technology cannot be easily transferred to other country too. Therefore, this technology is the most fundamental and necessary research area for the successful establishment of space environment system. Since the task for evaluating the effects of space materials and components by space radiation plays important role in satellite lifetime extension and running failure percentage decrease, it is necessary to establish simulated space radiation facility and systematic testing procedure. This report has dealt with the status of the technology to enable the simulation of space environment effects, including the effect of space radiation on ...

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Plantago ovata Forsk - an economically important medicinal plant - was analyzed for trace elements and chlorophyll in a study of the effects of gamma radiation on physiological responses of the seedlings. Proton-induced X-ray emission (PIXE) technique was used to quantify trace elements in unirradiated and gamma-irradiated plants at the seedling stage. The experiments revealed radiation-induced changes in the trace element and chlorophyll concentrations.

British Library Electronic Table of Contents (United Kingdom)

Biological wound dressings sterilized with gamma radiation, such as amnion and pig skin, are a reality in Mexico. These tissues are currently processed in the tissue bank and sterilized in the Gamma Industrial Irradiation Plant; both facilities belong to the Instituto Nacional de Investigaciones Nucleares (ININ) (National Institute of Nuclear Research). With the strong support of the International Atomic Energy Agency, the bank was established at the ININ and the Mexican Ministry of Health issued its sanitary license on July 7, 1999. The Quality Management System of the bank was certified by ISO 9001:2000 on August 1, 2003; the scope of the system is "Research, Development and Processing of Biological Tissues Sterilized with Gamma Radiation". At present, more than 150 patients from 16 hosp...

International Nuclear Information System (INIS)

The results of photoneutron spectra measurements for the reaction (#gamma#,n) on the Sr-88 nuclei near threshold are presented. The parameters of resonance levels, as well as radiative S_#gamma#"("1") and neutron S_n"("1") strength functions for transitions on the first excited level of Sr-87 were obtained. 2 refs.; 1 fig.; 1 tab.

Energy Technology Data Exchange (ETDEWEB)

We construct the time-dependent radiation model for the pulsar wind nebulae (PWNe), assuming that leptons are accelerated in resonant scattering with heavy nuclei, which are injected into the nebula by the pulsar. The equilibrium spectra of these particles inside the nebula are calculated taking into account their radiation and adiabatic energy losses. The spectra of {gamma}-rays produced by these particles are compared with the observations of the PWNe emitting TeV {gamma}-rays and predictions are made for the expected {gamma}-ray fluxes from other PWNe. Expected neutrino fluxes and neutrino event rates in a 1 km{sup 2} neutrino detector from these nebulae are also calculated. It is concluded that only the Crab Nebula can produce a detectable neutrino event rate in the 1 km{sup 2} neutrino detector. Other PWNe can emit TeV {gamma}-rays on the level of a few ...

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The book examines current experimental and clinical knowledge concerning the biological and biophysical effects of electromagnetic radiation, particularly that in the microwave range. The biophysical bases of the interaction of electromagnetic radiation with matter are reviewed with emphasis on biological systems, and the effects of radiation on critical biological systems, including the nervous, reproductive, visual and blood-forming systems are compared. Data concerning the lethal effects of nonionizing radiation is presented and characteristics of the effects of electromagnetic radiation on the whole mammalian organisms are examined. Various reactions of the neuroendocrine system to electromagnetic radiation are described, with particular attention given to the adrenal system, and the combined effects of ionizing and microwave radiation ...

International Nuclear Information System (INIS)

In view of the interest in the use of gamma irradiation to extend the storage life of pre-packaged foods a report is made on the effects of gamma radiation on the migration of Irganox 1076 and Irganox 1010, antioxidants present in food packaging plastics, into synthetic triglyceride fatty-food simulant HB307 and iso-octane. The extent of migration was assayed by h.p.l.c. techniques. Migration into HB307 and iso-octane decreased steadily as irradiation progressed suggesting that gamma irradiation of packaging materials helps to prevent the contamination of food by antioxidants in the packaging. (U.K.).

Energy Technology Data Exchange (ETDEWEB)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a {sup 60}Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used.

International Nuclear Information System (INIS)

Wood-plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, using three monomer systems; acrylamide, butylmethacrylate, and styrene, with methanol as the swelling solvent. Polymerization was induced at various radiation doses (10, 20, and 30 kGy) at a dose rate of 3.5 kGy/h using a "6"0Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength have been measured. The polymer loading decreases approximately with increasing density of the wood species used. (author)

International Nuclear Information System (INIS)

Formulae are derived for estimation of the effect of gamma beam divergence on the value of systematic and statistical components of the errors of density measurement in production of structural materials and products also in the process of exploitation of building structures and constructions. Engineering technique for choice of the distance between radiation source and object under test is developed for absorption radioisotope densimeter operating by the scheme of geometry of divergent beam with amplitude compensation of backscattered radiation effect. The assessment of radioisotope densimeter efficiency providing the error of density measurement prescribed at design stage

CERN Document Server

Relativistic strongly magnetized winds outflowing from fast-rotating compact objects like millisecond pulsars with surface magnetic fields of $\\sim 10^{15}-10^{16}$ G are plausible sources of cosmological $\\gamma$-ray bursts. In such winds, there are at least three regions where extremely powerful X-ray and $\\gamma$-ray emission may be generated. The first radiating region is the wind photosphere that is at a distance of $\\sim 10^9$ cm from the compact object. The second radiating region is at a distance of $\\sim 10^{13}-10^{14}$ cm. In this region, the striped component of the wind field is transformed into large-amplitude electromagnetic waves. The third radiating region is at a distance of $\\sim 10^{16}-10^{17}$ cm, where deceleration of the wind due to its interaction with an ambient medium becomes important. Radiation from all these regions is ...

Energy Technology Data Exchange (ETDEWEB)

The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The ...

International Nuclear Information System (INIS)

Remote-controlled handling systems are required for work to be done in the decommissioning and dismantling of nuclear facilities. These systems are equipped with electronic devices suitable for use in working environments affected by ionizing radiation. The publication explains the step-wise progress achieved for improving the radiation resistance of electronic devices with the example of a four-quadrant controlling device for the motors of a manipulator. The radiation resistance of the device could be enhanced to radiation energies of 5.500 Gy. This means that a manipulator vehicle equipped with this controlling device can take up to approx. 15 kGy all in all, taking into account its own shielding properties. (DG).

Energy Technology Data Exchange (ETDEWEB)

Radiation degradation of polycarbonate (PC) and polybutylene terephthalate (PBT) used as cable connector was evaluated using DSC, TGA, and mechanical properties. Glass transition temperature, melting temperature, 5% weight loss temperature, elongation at break, and tensile strength measurements were carried out for each of {gamma}-ray irradiated samples. In the results of those analyses, PC has radiation resistance better than PBT as a cable connector material.

International Nuclear Information System (INIS)

The decree refers to conditions of irradiation of food and its components for radappertization and radurization using gamma radiation from cobalt 60 or cesium 137, X radiation or electron beam up to maximum total medium absorbed dose 10 kGy.

Energy Technology Data Exchange (ETDEWEB)

This study evaluates the effect of gamma radiation on the viability of fungi and actinomycetes that contaminate medicinal plants. The relationship between the total lipids of some fungi and actinomycetes and their sensitivity to gamma radiation is also investigated. The data reveal that the viable counts of these florae decrease approximately exponentially with the radiation dose, the effective dose for the elimination of these microorganisms being about 5 kGy for all the medicinal plants under study. Response of pure cultures of fungi and actinomycetes isolated from medicinal plants to increasing absorbed doses of gamma radiation indicate that an increase in radioresistance is in the following order: Streptomyces rimosus, Fusarium solani, Nocardia kuroishii. F. oxysporum, A. fumigatus, A. flavus, A. parasiticus and A. ochraceus. The total ...

International Nuclear Information System (INIS)

The effect of pigments on the development of corrosion products between the painting system and metal surface when exposed to marine environments has been discussed. The pigments studied were: red mud zinc chromate, zinc chromate, red oxide zinc phosphate, manganese phosphate barium chromate and basic lead silico chromate. Moessbauer spectroscopy revealed that the upper rust layer in all the cases consisted of #gamma#-Fe_2O_3, #gamma#-FeOOH and #alpha#-FeOOH. The lower rust layer immediately in contact with the metal surface consisted of an asymmetrical doublet due to #gamma#-FeOOH. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

A historical perspective is given of the current paradigm that does not explicitly protect the environment from radiation, but instead, relies on the concept that if dose limits are set to protect humans then the environment is automatically protected as well. We summarize recent international questioning of this paradigm and briefly present three different frameworks for protecting biota that are being considered by the U.S. DOE, the Canadian government and the International Commission on Radiological Protection. We emphasize that an enhanced collaboration is required between what has traditionally been separated disciplines of radiation biology and radiation ecology if we are going to properly address the current environmental radiation problems. We then summarize results generated from an EMSP grant that allowed us to develop a Low Dose Irradiation Facility ...

International Nuclear Information System (INIS)

The Guarantee Outline presents the technical demands of design and contents of assessment for radiation hardening in satellite engineering in China. It includes the basis of design in space environment of polar orbit, the contents of design for general radiation hardening, the requirements and assessments of the single-board computer, the requirements of design for circuits (including hardware and software), the choices and assessments for devices, and the primary stipulations for the requirements of design and assessments against the phenomenon of charge and discharge.

International Nuclear Information System (INIS)

In future collider experiments, where a background radiation level is estimated to be very high, e.g. around 10"2 #approx# 10"5 Gy/yr and 10"1"1 #approx# 10"1"4 n/cm"2/yr at SSC, the detectors operating around the collision point in the experiments will encounter a considerable amount of radiation. Therefore, the detectors, especially the calorimeter, are required to be resistive against high radiation levels. From this point of view, it is of great importance to study the effects of radiation damage on the performance of the detectors. The authors report preliminary results of measurements of radiation hardness of the plastic scintillating fiber Kuraray SCSF-81 against irradiation with fast neutrons and "6"0Co #gamma#-rays in the region of the neutron fluence from 1 x 10"1"1 to 5 x 10"1"3 n/cm"2 and the integrated #gamma#-ray dose from 890 ...

International Nuclear Information System (INIS)

Treatment of food with low doses of gamma radiation has been recognized to have two main advantages. These consist of: (1) improvement of food safety by elimination of pathogens and (2) reduction of microbial spoilage and extension of shelf life of perishable items by reducing the number of viable spoilage organisms. Studies during the last few decades have conclusively proved the beneficial effects of radiation with respect to fishery products. The three potential areas of application to fish products include: (i) radurization for shelf life extension (ii) radicidation to eliminate food borne pathogens in the products and (iii) radiation treatment to dried products to control insects.

Energy Technology Data Exchange (ETDEWEB)

In principle four different methods (ultrasound, microwaves, {gamma}-radiation and x-rays) are available for the non-destructive testing of refractories. Three of these methods, i.e. ultrasound, microwaves and {gamma}-radiation, are in use by different producers of AZS materials to carry out the quality control of their products. This paper will compare the three methods on the basis of the physical properties, present the existing devices, and show the advantages as well as the limits of the different methods. {gamma}-radiography, the oldest method in use, has one main disadvantage, which is the requirement of protection against radioactive radiation. Furthermore, while cracks and cavities can be detected with this method, structural changes can not be monitored. Therefore, the ultrasonic method was developed that allows to detect variations of porosity and grain size as well as cracks and voids when ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

International Nuclear Information System (INIS)

One of the greatest opportunities for using of biomass as a precursor in the production of polymeric materials is the lignocellulose composites that can combine high performance with low costs. This work is a initial study on the production of a lignocellulose reinforced polyethylene composite. A compatibilization made by a induced gamma radiation grafting reaction was used to increase the adhesion between the matrix and the reinforced or filled fibers. The lignocellulose materials were exposed to gamma radiation in order to promote a molecular degradation and increase its reactivity. The polymer, the lignocellulose material and the compatibilization were processed by extrusion and the composite produced by this process were characterized by mechanical tests. (author)

International Nuclear Information System (INIS)

A method of using gamma radiation to determine the density and phase distribution in two-phase flows in pipes is described. Three collimated beams of radiation that pass through a pipe cross-section at different radial positions are used. A theory and computer program used to relate the measured attenuation of these beams to a three-parameter model of the phase distribution and to the average density and void fraction are discussed. Data obtained during both static and dynamic verification experiments using Lucite inserts are presented, as well as the results of several tests done in high pressure, steam-water flows.

International Nuclear Information System (INIS)

The #gamma#-radiation following thermal neutron capture in "1"0"0Mo has been studied by singles and coincidence measurements. A "1"0"1Mo level scheme has been deduced and is compared with the results of previous (d,p), (n,#gamma#) and "1"0"1Nb decay studies. The existence of the first excited state at 13.51 keV has been confirmed. The present data yield a neutron binding energy of 5398.4 KeV. (Auth.).

UK PubMed Central (United Kingdom)

Epidermal gamma delta T cells (γδ T) and Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A comment on the letter by T. Kajino and A. Arima Phys. Rev. Lett. 52, 739 (1984).

Energy Technology Data Exchange (ETDEWEB)

Both solvent extraction and spectrophotometric techniques were used to show the alterations that gamma radiation causes in the behavior of tetracycline molecule as far as its extracting and complexing power are concerned. The effect of gamma radiation on the solid tetracycline molecule, benzyl alcohol and on the solution of both was examined in solvent extraction systems whose aqueous phases were made up by {sup 152} Eu-{sup 154}Eu radioactive tracer solutions and whose organic phases were constituted by tetracycline-benzyl alcohol solutions. Experiments were performed in order to determine whether or not the water used for the pre-saturation of benzyl alcohol would influence the radiolysis of tetracycline. Solvent extraction and spectrophotometry were the techniques used to obtain the necessary data. Absorption spectra of irradiated tetracycline benzyl alcohol solutions submitted to several ...

Energy Technology Data Exchange (ETDEWEB)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 MeV is desirable. Key words: ...

International Nuclear Information System (INIS)

In the decoupling limit M_A_"0"2>>M_Z"2, the heavy CP-even, CP-odd, and charged Higgs boson masses are nearly degenerate, sin(#beta#-#alpha#) approaches 1, and the lightest CP-even Higgs boson almost displays the same properties as the standard model Higgs boson. But the top and bottom squark sectors can change this pattern through radiative corrections. We find that there are parameter regions at small and moderate tan #beta# in the minimal supersymmetry standard model under experimental constraints of (g-2)_#mu#, b#->#s#gamma#, and lower bounds of Higgs boson and sparticle masses, where sin"2(#beta#-#alpha#) is damped (say below 0.8), which has a significant effect on Higgs couplings g_h_"0_V_V(V=W"#+-#,Z"0) and g_h_"0_#gamma#_#gamma#. We discuss its impact on the lightest CP-even Higgs boson production at #gamma##gamma# colliders.

International Nuclear Information System (INIS)

Lupinus albus L. plants were grown from seeds and irradiated at various stages of development with acute or chronic gamma rays. All plants were greenhouse grown (pre- and post-irradiation) and allowed to proceed through their normal growth cycle. The purpose of these experiments was to establish a Plactochron Index for Lupinus albus L. and to determine the effects of acute and chronic irradiation on development at the macro and microscopic levels. A Plastochron Index was calculated and used as an indirect time scale to evaluate the effects of gamma rays from a common base line. Acute radiation treatment lasted for a period of a few days, whereas chronic treatment was initiated at the seedling stage and lasted for the entire growth season. Vegetative plants were used to study the effects of acute radiation exposure on apical meristem morphology, Plastochron Index, phyllatoxis and gross morphology.

International Nuclear Information System (INIS)

In radiation processing of food, the product often has to be prepackaged to prevent microbial recontamination during and after irradiation. The packaging material is exposed to radiation during radiation processing and radiation stability is a key consideration in the selection of packaging materials. The effects of ionizing radiation on many food packaging materials at the dose levels recommended for food precessing can be minimized by selecting appropriate radiation resistant materials. It is important to select materials in which chemicals formed as a result of the radiation treatment do not migrate and interact with the food, affecting its organoleptic and toxicological aspects. It is also important to select materials in which the physical properties are not altered to the extent they cannot resist damage during commercial production, ...

International Nuclear Information System (INIS)

Sesame varieties/genotypes showed a good response to radiation with gamma rays and treatments with EMS. In M_1 both gamma rays and EMS influenced germination, seedling height, survival of plants and pollen fertility/sterility, producing deleterious effects on these characters. Compared to black seeded genotypes, white seeded ones are more susceptible to radiation. Both gamma rays and EMS produced various types of morphological variations in M_2 generation. These were dwarf plant mutants, mottled and fleshy leaved mutants (sterile), fasciated stem, flower colour, altered phyllotaxy, early, uniculm, capsule size variations, multiple capsule/leaf axil, seed coat colour variations, indehiscent and semi-indehiscent type mutants. Moreover, studies on quantitative characters including seed yield revealed the induction of mutants in both positive and negative directions for such traits ...

Energy Technology Data Exchange (ETDEWEB)

The proton beam has an advantage of the sharp dose falloff in dose distribution called Bragg peak while conventional radiation therapy modalities such as photons exhibit considerable amount of exit dose. To take advantage of this property it is important to know the exact location of the distal dose falloff. An error can cause overdose to the normal tissue or underdose to the tumor volume. The only way of finding out the dose distribution in-situ in particle therapy is to measure the gammas produced by nuclear reactions with tissue materials. Two kinds of gammas can be used: one is prompt gamma and the other is coincident gamma from the positron-emission isotopes. We chose to detect prompt gammas, and developed a prompt gamma scanning system (PGS). The proton beams of the proton therapy facility at National Cancer Center were used. The ...

International Nuclear Information System (INIS)

Practical procedures were developed for large-scale microbial decontamination of dry egg powder and gelatine with gamma radiation ("6"0Co). The formation and lifes of free organic radicals in these materials were examined by ESR measurements of powder samples. The concentration of these radicals was studied in dependence on the time of storage. Secondary oxidation of egg fats by air oxygen was investigated. Sensoric tests of irradiated gelatine, both in powder and hydrogel form, were performed. (author). 4 figs., 2 tabs., 2 refs.

Energy Technology Data Exchange (ETDEWEB)

Energy spectra of the Bragg reflection of the Moessbauer ..gamma..-radiation from the /sup 57/Fe/sub 3/BO/sub 6/ weakly ferromagnetic monocrystal are studied. A strong effect of the interference transitions in iron nuclei, being in non-equivalent positions, on the spectra form is revealed. The measurement results are compared with theoretical calculations.

International Nuclear Information System (INIS)

A facility for studying photon-neutron reactions under a braking #gamma#-beam with an energy of up to 26 MeV from a betratron includes Saratov-2, SM-4A, and IBM AT-386 microcomputers. Neutron detectors, pulsed braking radiation dosimeters, and the devices to control the betatron energy are described.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The effects of gamma and e-beam irradiation on mechanical and structural properties of nylon 66 (Ny 66), nylon 6 (Ny 6) and poly(ethylene terephthalate) (PET) fabrics used in tyres were investigated. The untreated (greige), treated cords and calendered fabrics were irradiated at different doses. It is found that the effects of high energy irradiation on greige, treated cords and calendered fabrics are similar. No protective effect of compounds used in calendering was observed against radiation-induced oxidative degradation. The deterioration effect of gamma irradiation on mechanical properties is much higher than that of e-beam irradiation for all types of samples. Limiting viscosity numbers of both gamma and e-beam irradiated nylon 6 and nylon 66 cords were found to decrease with increasing dose. It is concluded that PET calendered fabric has higher resistance to ionizing ...

Energy Technology Data Exchange (ETDEWEB)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/..gamma.. ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time ..gamma.. spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded ..gamma.. spectra created by the photopeak-Compton edge combination in ...

Science.gov (United States)

Personnel radiation monitoring is essential to the operation of any nuclear facility and work in this area continues to strive for an accurate determination of personnel dose. In particular recent attention has been focused upon the need to improve the accuracy of neutron dosimetry, mainly because of their high Relative Biological Effectiveness. In this work the feasibility of using the NE-213 liquid scintillation detector as an efficient neutron/gamma ray radiation monitor is demonstrated. Derivative method spectrum unfolding used in MATXUF for on-line analysis of fast neutron spectra has also been applied to real time gamma spectrum unfolding (MATXUF2), making possible simultaneous on-line monitoring of both fast neutrons and gammas. To eliminate the negative fluxes in the unfolded gamma spectra created by the photopeak-compton edge combination in the plateau ...

International Nuclear Information System (INIS)

The neutron capture cross sections of the stable molybdenum isotopes have been measured with high energy resolution (#DELTA#E/E < approximately 0.2%), between 3 and 90 keV neutron energy, at the 40 m station of ORELA. Average resonance parameters are extracted for s- and p-wave resonances. The s-wave neutron strength function is close to 0.5x10"-"4 for all isotopes, but the p-wave strength function exhibits a well defined peak near A approximately 95. Both s- and p-wave radiative widths decrease markedly as further neutrons are added to the closed shell. The p-wave radiative widths are generally greater than the s-wave widths showing the presence of non-statistical #gamma#-decay mechanisms. Valence neutron theory fails to explain the magnitude of the p- to s-wave radiative width disparity and doorway state processes are invoked. In particular, the data for "9"8Mo appear to violate the usual valence ...

International Nuclear Information System (INIS)

We study CP-violating phenomena in the production, mixing and decay of a coupled system of CP-violating neutral Higgs bosons at #gamma##gamma# colliders, assuming a Minimal Supersymmetric Standard Model (MSSM) Higgs sector in which CP violation is radiatively induced by phases in the soft supersymmetry-breaking gaugino masses and third-generation trilinear squark couplings. We discuss CP asymmetries in the production and decays of #mu#"+#mu#"-, #tau#"+#tau#"-, b-bar b and t-bar t pairs. We find large asymmetries when two (or all three) neutral Higgs bosons are nearly degenerate with mass differences comparable to their decay widths, as happens naturally in the CP-violating MSSM for values of tan#beta#-bar 5 (30) and large (small) charged Higgs-boson masses.

International Nuclear Information System (INIS)

We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s_#gamma#_#gamma# similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).

Energy Technology Data Exchange (ETDEWEB)

Kinetics of postradiation polymerization of triethylene glycol ..cap alpha.., ..omega..-dimethacrylate has been studied by calorimetric method. The low-temperature radiolysis has been studied by ESR method. The radiation-chemical yield of radicals on ..gamma..-irradiation by /sup 60/Co is determined being equal to 6+-1 1/100 ev. Transformation of the radicals spectrum into the spectrum of propagating macroradicals proceeds at 140 K. After the transition from glassy to liquid state (Tsub(g)=193 K) the intensive postpolymerization begins. During the polymerization the disappearance of radicals is observed. For the low-temperature region the effective activation energy of polymerization is determined beina equal to 50.7+-0.8 kJ/mol.

International Nuclear Information System (INIS)

We have studied in detail the gamma radiation induced changes in the electrical properties of the (TeO_2)_0_._9 (In_2O_3)_0 _._1 thin films of different thicknesses, prepared by thermal evaporation in vacuum. The current-voltage characteristics for the as-deposited and exposed thin films were analysed to obtain current versus dose plots at different applied voltages. These plots clearly show that the current increases quite linearly with the radiation dose over a wide range and that the range of doses is higher for the thicker films. Beyond certain dose (a quantity dependent on the film thickness), however, the current has been observed to decrease. In order to understand the dose dependence of the current, we analysed the optical absorption spectra for the as-deposited and exposed thin films to obtain the dose dependences of the optical bandgap and energy width of band tails of the localized states. The increase of the ...

International Nuclear Information System (INIS)

The virucidal effect of _6_0Co gamma radiation was studied in cell culture medium and in liquid swine manure involving the most important porcine viruses that can be spread by liquid manure. The radiation doses (20 kGy and 30 kGy) were determined in preliminary experiments employing a porcine enterovirus from the serogroup 1 (Teschen group). In the main experiment, the following viruses were employed: swine vesicular disease (SVD) virus, type C foot-and-mouth disease (FMD) virus, a field strain of Aujeszky's disease (AD) virus, transmissible gastroenteritis (TGE) virus, as well as bovine viral diarrhoea (BVD) virus. The latter strain served as a model for hog cholera virus. The results of the experiments indicate that safe disinfection of the virus infected liquid swine manure by ionizing radiation requires a radiation dose of 30 kGy. (author).

Energy Technology Data Exchange (ETDEWEB)

Radiological hazard in uranium mining and milling operations are primarily due to exposure to external beta and gamma radiation as well as to airborne radionuclides which consist of radon and its short-lived daughter products. In May 1981 a radiological survey programme was performed in order to make a general assessment of the radiation hazards associated with the uranium mines and the Uranium Pilot Plant operated by the M.T.A. Institute in the Koprubasi district of the Manisa province. In this paper a preliminary radiological risk evaluation attempt is presented based on the radiation and radioactivity measurements performed in this district in May 1981.

Energy Technology Data Exchange (ETDEWEB)

In order to evaluate the effects of radioactivity on active vegetal substances, samples of Fennel (Foeniculum vulgare Miller., fructus), Guarana (Paulinia cupana, Kunth, semen), Gingko (gingko biloba, L., folium), and Kawa-Kawa (Piper methysticum G. Forst, rhizoma), were treated with scaling doses (0 to 25 KGy) of gamma radiation (Co{sup 60}). The 'blind test' methodology was used. The active substances from each sample were analysed by qualitative and quantitative methods after radiation. There were no significant differences seen between the control sample (0 KGy) and the irradiated samples. Microbe contamination was significantly reduced, about 10000 CFU/g, with the initial 5 KGy dose. It was concluded that gamma radiation can be used as an alternative procedure to reduce microbiologic contamination in medicinal plants. Before this procedure can be extended to ...

Energy Technology Data Exchange (ETDEWEB)

This document presents the SSI preliminary views and position concerning the decommissioning of nuclear plants. To prevent the exposure of the decommissioning personnel and the general public to unacceptable levels of radiation and to protect the environment and future generations, it is SSI`s task to formulate and issue the necessary terms and regulations with which the reactor licensees must comply during the decommissioning work. The views and principles presented here are the basis of SSI`s continued work on guidelines and regulations for the decommissioning of nuclear plants.

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Natural radioactivity found in rocks and its evaluation been frequently used for studies of environmental geochemistry, particularly those of detection and control of pollutants and the consequent changes in environment after antropic interferences. In this work natural radioactivity in forty nine soil samples in the basin of Buquira river, at the Northeast region of Sao Paulo State, has been analysed and measured with a Ge-HP gamma ray spectrometer. A table with the most relevant results found in rocks is shown and discussed. (author)

International Nuclear Information System (INIS)

Chemical effects of L X-ray intensity ratios in niobium and molybdenum compounds were studied by electron and proton bombardments. L_#gamma#_1 X-rays which involve transition of 4d electrons of the valence shell were found to be sensitive to the chemical environment. The L_#gamma#_1/L_#beta#_1 X-ray intensity ratio increased with an increase of the 4d electron occupation of niobium or molybdenum in niobium or molybdenum compounds, showing that the chemical effects can be ascribed to the 4d electron behavior of the metallic atom in its compounds. (orig.).

International Nuclear Information System (INIS)

Alanine/EPR Dosimetry system is classified as a reference-standard dosimeter which used to calibrate radiation environments and to calibrate routine dosimeters in absorbed dose range of 1 to 105 Gy. Characteristics of Alanine/EPR dosimetry system are better suitable than routinely used personnel dosimeters for the long term radiation measurement in harsh condition of Nuclear power plant : This system is not significantly affected by temperature and humidity and also has low fading rate. About 1 year ago, Alanine and Lithium compound dosimeters were installed at Wolsung unit 1 for the environment monitoring as a part of equipment qualification program. 35 positions which are most severe and representative cable positions were chosen for radiation and temperature monitoring. The recovered alanine dosimeter in the period of maintenance was measured by E-scan alanine analyzer system, ...

International Nuclear Information System (INIS)

In quantifying health risks arising from radiation exposure and synergistic effects promoted by radiation the dose-effect relationship must be used as a basis. Special problems arise in the extrapolation of experimental results or in the treatment of data in the region of low doses administered over long periods of time. For radiation protection purposes, especially manifestations of cancer and genetic effects are significant. The International Commission on Radiation Protection has published binding guiding values on the basis of which to assess the risk of cancer. The cancer risk and genetic risks are estimated for relevant dose ranges and compared with other factors of civilization. For the most important chemical pollutants emitted into the environment the possibilities of impacts arising from synergistic effects are discussed on the basis of the rules and regulations specified ...

Energy Technology Data Exchange (ETDEWEB)

Prior to routine use, all newly installed x-ray machines must have a radiation-protection survey by a qualified expert. The survey is an evaluation of existing or potential radiation hazards associated with the use of diagnostic x-ray equipment under specific conditions. Such evaluation includes the measurement of exposure levels in the environment as well as environmental levels arising from operation of the equipment. The survey also includes an evaluation of the safety characteristics of the x-ray unit.

Energy Technology Data Exchange (ETDEWEB)

Diffuse {gamma}-ray emission produced by the interaction of cosmic-ray particles with matter and radiation in the Galaxy can be used to probe the distribution of cosmic rays and their sources in different regions of the Galaxy. With its large field of view and long observation time, the Milagro Gamma Ray Observatory is an ideal instrument for surveying large regions of the Northern Hemisphere sky and for detecting diffuse {gamma}-ray emission at very high energies. Here, the spatial distribution and the flux of the diffuse {gamma}-ray emission in the TeV energy range with a median energy of 15 TeV for Galactic longitudes between 30{sup o} and 110{sup o} and between 136{sup o} and 216{sup o} and for Galactic latitudes between -10{sup o} and 10{sup o} are determined. The measured fluxes are consistent with predictions of the GALPROP model everywhere except for the Cygnus region (l ...

Energy Technology Data Exchange (ETDEWEB)

The primary responsibility of the Health, Safety, and Environment (HSE) Division at the Los Alamos National Laboratory is to provide comprehensive occupational health and safety programs, waste processing, and environment protection. These activities are designed to protect the worker, the public, and the environment. Many disciplines are required to meet the responsibilities, including radiation protection, industrial hygiene, safety, occupational medicine, environmental science, epidemiology, and waste management. New and challenging health and safety problems arise occasionally from the diverse research and development work of the Laboratory. Research programs in HSE Division often stem from these applied needs. These programs continue but are also extended, as needed to study specific problems for the Department of Energy and to help develop better occupational health and safety practices.

British Library Electronic Table of Contents (United Kingdom)

Polymer insulating materials used in radioactive environments are subjected to a risk of surface degradation caused by tracking. The tracking behavior becomes more complex with the presence of magnetic field. This paper presents investigation of tracking failure of gamma-ray irradiated polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) under magnetic field. The samples were irradiated in air up to 100 kGy and then up to 1000 kGy with dose rate of 10 kGy/h by using a 60Co gamma-source. Magnetic field Formula Not Shown with flux density of 250 mT was assembled perpendicularly to electric field Formula Not Shown , which gave rise to relative angle between Formula Not Shown and surface normal vector Formula Not Shown of 0degree, 90degree and 180degree, respectively. The experi...

Energy Technology Data Exchange (ETDEWEB)

Wood sawdust has been applied to manufacture the sawdust-clay-plastic composite (SDCPC) by radiation process for the purpose of disposing large amount of wood sawdust waste material. The process comprises the impregnation of liquid vinyl monomers into the completely dried molded sawdust-clay specimens followed by exposure to Co-60 gamma-radiation to induce graft-copolymerization of the impregnated vinyl monomers onto the sawdust-clay matrix. The comonomer system of unsaturated polyester and vinyl compounds was found to be the ideal impregnating monomer for the preparation of the SDCPC from the viewpoint of the technological and economical advantages. The SDCPC material has a variety of the sawdust content which enables the composite to have wide range of mechanical properties, e.g., 410 to 1100 kg/cm/sup 2/ in compressive strength, 120 to 380 kg/cm/sup 2/ in tensile strength and 0.32 to 4.41 kg/mm/sup 2/ in static bending strength. The SDCPC ...

International Nuclear Information System (INIS)

Development of food preservation and processing techniques by radiation was performed. Gamma irradiation at 2-10 kGy is considered to be an effective method to control pathogenic bacteria in species including Escherichia coli O157:H7. Gamma irradiation at 5 kGy completely eliminated pathogenic bacteria in beef. Gamma irradiation at such doses and subsequent storage at less than 4 deg C could ensure hygienic quality and prolong the microbiological shelf-life resulting from the reduction of spoilage microorganisms. Gamma irradiation on pre-rigor beef shortens the aging-period, improves tenderness and enhances the beef quality. And, a new beef processing method using gamma irradiation, such as in the low salt sausage and hygienic beef patty was developed. Safety tests of gamma-irradiated meats(beefs: 0-5 kGy; porks: 0-30 kGy) in areas such as ...

Energy Technology Data Exchange (ETDEWEB)

Using {gamma}-irradiation-induced reduction in the field of a {sup 60}Co {gamma}-ray source, colloidal silver and gold nanoparticles were prepared from their corresponding metal salts in aqueous solution and compared with those by chemical reduction. The radiation-based method provided silver nanoparticles with higher concentration and narrower size distribution than those obtained by chemical reduction method while there was no significant difference between the two strategies for the preparation of gold nanoparticles. {gamma}-Irradiation of 1.0 x 10{sup -3} M AgNO{sub 3} solution resulted in nearly 100 times more highly concentrated silver colloids than those by citrate reduction. Furthermore, the radiation method could lead to more highly concentrated silver colloids by simply increasing the concentration of AgNO{sub 3} solution up to 2.0 x 10{sup -2} M. The two metal ...

International Nuclear Information System (INIS)

The main problems arising in decommissioning nuclear-powered submarines (NPS) relate to choosing a concept of handling reactor compartments followed by handling technology development. Reactor compartments (RC) are characterized with extremely space-saving or integral layout of large-size power equipment and systems, restricted access for dismantling, high radiation dose rates in a number of bays of RC. The above RC features pose a problem to find optimum option of RC utilization which on the one hand would be the most cost efficient, and the safest as possible on the other, i.e. dose commitments of personnel involved should be minimum, and effect on population and environment should be negligible. The main radiation factors specifying safety in RC handling at any decommissioning stage are as follows: (1) total radioactivity integrated in reactor facility (RF); (2) distribution of this radioactivity through RF equipment and ...

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The radiation control carried out in Atomic Energy Research Institute, Kinki University, for the reactor installation and the tracer/accelerator facilities from April, 1981, to March, 1982, is described. The reactor was operated for total 1057.1 hours at the maximum heat output of 1 W. The persons subject to radiation protection as of April, 1981, were 126 persons in all, including 23 in radiation work and 11 in X-ray work, etc. The contents of this report are as follows: personnel monitoring (health examination, the control of individual exposure dose); laboratory monitoring (the measurement of area dose rate, radioactive concentration in air and water, and surface contamination density); field monitoring (environmental ..gamma..-ray dose rate, radioactive concentration in environmental samples); the use of unsealed radioisotopes, etc.

International Nuclear Information System (INIS)

It has been prepared composites materials by means of monomer penetration in pores of wood samples and later curing by means of gamma irradiation. The studied species were Hura crepitans L. (catahua), Aniba puchury-minor (C. Martinez) (mohena amarilla), and Calycophyllum spruceanum (Benth.) (capirona). These new materials exhibit smaller water absorption and better mechanical properties in comparison with native wood. The test tubes of catahua treated with the styrene-polyester mixture absorb only up to 10% humidity compared to the native species whereas its hardness is increased in a 100%. (author).

CERN Document Server

Attention is paid to the production mechanisms of light scalars that reveal their nature. We reveal the chiral shielding of the \\sigma(600) meson. We show that the kaon loop mechanism of the \\phi radiative decays, ratified by experiment, points to the four-quark nature of light scalars. We show also that the light scalars are produced in the two photon collisions via four-quark transitions in contrast to the classic P wave tensor q\\bar q mesons that are produced via two-quark transitions $\\gamma\\gamma\\to q\\bar q$. The history of spontaneous breaking of symmetry in quantum physics is discussed in Appendix.

International Nuclear Information System (INIS)

Bases of the algorithm for assessing the reinforcement status in reinforced concrete products by gamma-absorption method are presented. Analytical equations are obtained for estimation of error of the parameter characterizing the degree of reinforcement destruction. It is recommended to use high-energy Bremsstrahlung sources-betatrons of 4-10 MeV maximum energy for testing products of 500-600 mm thick. Linear radiation attenuation factor (LAF) of concrete in estimated equation is replaced by effective LAF of concrete, and LAF of reinforcement and corrosion materials - by differential LAF. Corresponding LAF of nonevident form in the algorithm is assessed by the results of processing of direct-shadow radiographs of defectometers

International Nuclear Information System (INIS)

In order to qualify corrosion resistant materials for high level waste (HLW) packagings acting as a long-term barrier in a rock salt repository, the corrosion behaviour of the preselected materials Ti 99.8-Pd, Hastelloy C4 and two unalloyed steels was investigated. The resistance of the materials to general corrosion, local corrosion and stress corrosion cracking was examined under postulated accident conditions in the repository by long-term immersion tests of up to 4 years duration and electrochemical methods. The parameters investigated were different salt brines, temperatures of 90 deg. C, 170 deg. C and 200 deg. C as well as a gamma radiation field of 10"3Gy/h (10"5rad/h). Among the materials studied, Ti 99.8-Pd exhibited the highest corrosion resistance. This material corroded at a very low rate (gamma radiation, and proved to be resistant to local corrosion and ...

International Nuclear Information System (INIS)

Ignoring the numerous, known and mainly unknown, interactions between chemicals and ionizing radiations, causes strong controversy about the risks of ionizing radiations. Yet the best known interactions between chemicals and radiations is that between radon and tobacco smoke. Although it is and it will be always impossible to derive quite quantitative laws for this interaction, it has been possible to derive some semi-quantitative relationships based on reasonable assumptions and statistics on lung cancer deaths in developed countries. They show that ignoring the dangers of tobacco smoking as we did still long after we had recognised the dangers of radiations, could asses to radiations thirty or forty times more risks than reality. As present world is flown by tens of thousands chemicals, little or not present in a natural environment, and as it would be very ...

International Nuclear Information System (INIS)

The ability of the R46 R factor and its derivative pKM101 to modify sensitivity to "6"0Co #gamma# radiation was studied. In Escherichia coli K12 both plasmids enhanced bacterial survival after "6"0Co #gamma# irradiation. This effect was dependent on recA"+ genotype but not on recB"+, recB"+recC"+, and recF"+ genotypes. 5-Fluorouracil eliminated the R46 R factor from the parent and its rec"- mutant strains. These strains lost not only the antibiotic resistance coded for R46 R factor but their radioresistance as well.

Energy Technology Data Exchange (ETDEWEB)

Three electronic personal dosimeters (EPD-N) manufactured by Siemens, serial numbers 0635, 0658, and 0683, were tested at the Radiation Calibration Laboratory for an evaluation of their response to neutron, gamma and x-ray radiation. Designed to provide real-time neutron and photon dosimetry, the EPD-N is capable of estimating and displaying neutron and gamma dose components separately for a range of energies from 50 keV to 7 MeV for photon and 0.025 eV to > 10 MeV for neutron. All tests were conducted using the factory calibrations. A technical representative of the manufacturer indicated that site-specific calibrations are required as factory settings are calibrated for the lowest neutron energy limit of 0.025 eV. This raises concerns about the reliability of these devices in measuring neutrons when calibrations are made for a specific site radiological characterization then used at another ...

International Nuclear Information System (INIS)

Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85"0C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to #gamma#-rays. A thin aluminium foil was used to cover the inner wall of the reaction vessel so that the extent of homo polymer could be reduced to be less than 1.6% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmations of graft copolymerization and saponification reactions were made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the same total dose on the extent of grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

British Library Electronic Table of Contents (United Kingdom)

For the safety of astronauts and to ensure the stability and integrity of the genome of microorganisms and plants used in bioregenerative life support systems, it is important to improve our knowledge of the combined action of (space) radiation and microgravity. The SOS-LUX-TOXICITY test, as part of the TRIPLE-LUX project (accepted for flight at Biolab in Columbus on the International Space Station, (ISS)), will provide an estimation of the health risk resulting from exposure of astronauts to the radiation environment of space in microgravity. The project will: (i) increase our knowledge of biological/health threatening action of space radiation and enzymatic DNA repair; (ii) uncover cellular mechanisms of synergistic interaction of microgravity and space radiation; (iii) provide specified...

British Library Electronic Table of Contents (United Kingdom)

To test the effect of humidity on the radiation resistance of Deinococcus radiodurans, air-dried cells were irradiated with germicidal 254?nm UV, and simulated environmental UV or ?-radiation and survival was compared to cells in suspension. It was observed that desiccated cells exhibited higher levels of resistance than cells in suspension toward UV or ?-radiation as well as after 85?C heat shock. It was also shown that low relative humidity improves survival during long-term storage of desiccated D. radiodurans cells. It can be concluded that periods or environments in which cells exist in a dehydrated state are beneficial for D. radiodurans? survival exposed to various other stresses.

Energy Technology Data Exchange (ETDEWEB)

The project was designed to solve the infra structural problem required for commercialization of food irradiation. In improvement of physical properties of corn starch, gamma irradiation was effective for increasing glucose productivity and for substituting traditional modified starches (acid modified starch, oxidized starch). In immobilization of microorganisms, the mass production method of natural red pigment was developed by using immobilized mold pellets. In Korean medicinal plants, 10 kGy gamma irradiation was effective for improving sanitary quality and increasing extraction yield. In evaluation of wholesomeness, gamma irradiated red ginseng could be safe on the genotoxic point of view. And also, six items of irradiated foods approved for human consumption from Korea ministry of health and welfare in May 19, 1995. 30 figs, 20 tabs, 54 refs. (Author).

Energy Technology Data Exchange (ETDEWEB)

In the investigations reported here, a helium-jet/tape-transport system was used for the rapid transfer of fission products to a low-background environment where their aggregate beta and gamma-ray spectra were measured as a function of delay time after neutron induced fission of {sup 235}U, {sup 238}U and {sup 239}Pu. Beta and gamma-ray energy distributions have been deduced for delay times as short as 0.2 s and extending out to 100,000s. Instrumentation development during the initial phase of the project included: (1) assembly and characterization of a NaI(Tl) spectrometer for determining aggregate gamma-ray energy distributions, (2) development and characterization of a beta spectrometer (having excellent gamma-ray rejection) for measuring aggregate beta-particle energy distributions, (3) assembly and characterization of a Compton-suppressed HPGe spectrometer for determining ...

International Nuclear Information System (INIS)

The production of three vector bosons in #gamma# #gamma# collisions studying the reactions #gamma# + #gamma# #-># W"+ + W"- + Z"0 and #gamma# + #gamma# #-># W"+ + W"- + #gamma#. 12 refs., 4 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

Monolithic N-channel junction field effect transistors (NJFETs) dc characteristics, small signal parameters and noise have been studied from 300 K down to cryogenic temperatures before and after irradiation with {sup 60}Co {gamma}-rays and fast neutrons (1 MeV). Radiation induced effects on dc parameters and noise are reviewed. Noise spectral density measurements performed at various temperatures have shown that the radiation induces a noise increase which is temperature and frequency dependent. (orig.). 14 refs.

International Nuclear Information System (INIS)

Ionizing radiation, mainly in the form of #gamma#-rays from the radioisotope cobalt 60, is being used increasingly for the inactivation of contaminants in cosmetic and toiletry preparations. The treatment is applied to the product in its final pack, and therefore, it is important to recognize that the properties of the packaging materials could be affected, particularly if high radiation doses are used. The stability of a wide range of materials is discussed. The nature and extent of chemical and physical changes in plastics very much depends on the presence of antioxidants and other additives, and on the environmental conditions during irradiation. Some useful information is available from research into the use of radiation for the preservation of food - many films and laminates have been cleared for use in the United States. The low radiation doses used for the control of ...

Energy Technology Data Exchange (ETDEWEB)

As for Wolsung NPP unit 1, radiation shielding analysis was performed by using neutron diffusion codes, one-dimensional discrete ordinates code ANISN, and analytical methods. But for Wolsung NPP unit 2, 3, and 4, two-dimensional discrete ordinates code DOT substituted for neutron diffusion codes. In other words, the method of analysis and computer codes used for radiation shielding of CANDU 6 type reactor have been improved. Recently Monte Carlo MCNP code has been widely utilized in the field of radiation physics and other radiation related areas because it can describe an object sophisticately by use of three-dimensional modelling and can adopt continuous energy cross-section library. Nowadays Monte Carlo method has been reported to be competitive to discrete ordinate method in the field of radiation shielding and the former has been known to be superior to the latter for complex ...

International Nuclear Information System (INIS)

The integrity of helium circulation loop flanged joints has been attracting recent attention as a design problem, in the development of high-temperature facilities incorporating helium loops (e.g., the VRG-50 pilot nuclear facility). Elevated temperatures and pressures, and the radiation environment, impose additional requirements on sealant materials. This applies first and foremost to rubber seals, which have found widespread favor on account of its excellent elasticity, its ability to spontaneously conform to possible changes in the clearance in the seal assembly, and the low compressive stresses developed in the flange joint assembly.

International Nuclear Information System (INIS)

The notion of hardened systems can be found in several applications (nuclear power plants, alarm systems, research installations..). Their development correspond to the functional necessity to take into account a specific radiative environment. The starting point of each hardening study is the definition of the radiative environmental constraints representative of the application. In addition to these external constraints, the specific functional characteristics of each system are considered: control or interface systems in nuclear industry, in-board control systems, remote handling systems, etc. This paper summarizes the methodology followed according to the experience gained in previous studies and anticipating the future needs. (J.S.). 6 refs., 5 figs.

International Nuclear Information System (INIS)

This research report discusses the radiation hardening of a commercially available mobile robot, the REMOTEC ANDROS. This hardening effort is culminating in the availability of a megarad hardened mobile platform to access areas in nuclear facilities with extremely high levels of radiation (0.1 to 1 Mrad). These radiation levels may be encountered both during routine repair and monitoring activities and accident situations. The project has completed a phase-I U.S. Department of Energy Small Business Innovative Research contract and is now in a phase-II effort with completion scheduled in early 1995. The research involves the evaluation of the material and electrical components of an ANDROS robot to determine the anticipated radiation hardness of the current production version and evaluation of the components that must be replaced or modified to harden the system to higher radiation ...

International Nuclear Information System (INIS)

Radicals formed in gamma-irradiated crystals of galactose and glycine were found, upon dissolution, to cause mutagenesis of Salmonella typhimurium strains TA-98 and TA-100. Although the reproducibility of the results has not been adequately determined, they suggest the possibility of developing a test to measure the mutagenic-carcinogenic potential of radiation-induced free radicals with a microbial system.

Energy Technology Data Exchange (ETDEWEB)

Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN ...

CERN Document Server

The indirect detection of particle dark matter (DM) is based on the search for anomalous components in cosmic rays (CRs) due to the annihilation of DM pairs in the galactic halo, on the top of the standard astrophysical production. These additional exotic components are potentially detectable at Earth as spectral distortions for the various cosmic radiations: $\\chi + \\chi \\to q \\bar{q}, W^+ W^-, ... \\to \\bar{p}, \\bar{D}, e^+ \\gamma and \

CERN Document Server

We report the first observation of the radiative decay B^0 -> \\phi K^0 \\gamma using a data sample of 772 x 10^6 B B-bar pairs collected at the \\Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We observe a signal of 37+/-8 events with a significance of 5.4 standard deviations including systematic uncertainties. The measured branching fraction is ${\\cal B}(B^0 -> \\phi K^0 \\gamma) = (2.74\\pm 0.60 \\pm 0.32) \\times 10^{-6}$, where the uncertainties are statistical and systematic, respectively. We also report the first measurements of time-dependent CP violation parameters: ${\\mathcal S}_{\\phi K_S^0 \\gamma} = +0.74^{+0.72}_{-1.05} (stat)^{+0.10}_{-0.24} (syst)$ and ${\\mathcal A}_{\\phi K_S^0 \\gamma} = +0.35 +/- 0.58 (stat)^{+0.23}_{-0.10} (syst)$. Furthermore, we measure ${\\mathcal B}(B^+ -> \\phi K^+ ...

International Nuclear Information System (INIS)

The effect of ionizing radiation (2, 5, and 10 KGy of gamma rays) on muscle ultrastructure of grass shrimps (Penaeus monodon Fabricius) tails at ambient or frozen (-18"0C) temperature was investigated by transmission electron microscopy (TEM). No significant change was found in muscle ultrastructure of shrimp meat irradiated at doses of 2 or 5 KGy and then stored at 4"0C for 0 and 8 days. However, in shrimps which were irradiated at ambient temperature at a dose of 10 KGy, the margin of A-band of the myofibrils in longitudinal sections exhibited an irregular zig-zag pattern. In cross section some myosin filaments in the A-band regions were missing. A possible interpretation of these results would be that 10 KGy gamma irradiation dose at ambient temperature depolymerized myosin in the A-band from the tail of thick filament. Actin damage was also observed in some cross sections. Irradiation damage of sarcoplasmic membranes ...

Science.gov (United States)

Oncospheres produced by a nonirradiated worm and oncospheres produced by a worm that had been subjected to high gamma radiation (successive generations of cysticercoids were irradiated with 15,000 r until a cumulative dose of 120,000 r was obtained) were compared. Radiation had no effect on the sizes of the embryos, the shell, and the median hooks. Radiation may have resulted in certain large, hookless embryos that did not occur in the normal worm. Two anomalies, reduced hook number and failure of growth, were more frequent in the normal than in the irradiated worm. This result, although surprising, can be explained by the high selection pressure operating under the experimental conditions. (auth)

CERN Document Server

The development of a replacement to the conventional film based X-ray imaging technique is required for many reasons. One possible route for this is the use of a large area film of a suitable semiconductor overlaid on an amorphous silicon readout array. A suitable semiconductor exists in cadmium telluride and its tertiary alloy cadmium zinc telluride. In this thesis the spectroscopic characteristics of commercially available CZT X- and gamma-radiation detectors are established. The electronic, optical, electro-optic, structural and compositional properties of these detectors are then investigated. The attained data is used to infer a greater understanding for the carrier transport in a CZT radiation detector following the interaction of a high energy photon. Following this a method used to fabricate large area films of CdTe on a commercial scale is described. This is cathodic electrodeposition from an aqueous electrolyte. The theory and ...

International Nuclear Information System (INIS)

Treatment with gamma and electron radiation is becoming a common process for the sterilization of packages, mostly made of natural or synthetic plastics, used in the aseptic processing of foods and pharmaceuticals. The effect of irradiation on these materials is crucial for packaging engineering to understand the effects of these new treatments. Packaging material may be irradiated either prior to or after filling. The irradiation prior to filling is usually chosen for dairy products, processed food, beverages, pharmaceutical, and medical device industries in the United States, Europe, and Canada. Radiation effects on packaging material properties still need further investigation. This paper summarizes the work done by different groups and discusses recent developments in regulations and testing procedures in the field of packaging technology.

Energy Technology Data Exchange (ETDEWEB)

Short communication.

International Nuclear Information System (INIS)

The possibility to transform the future linear e"+e"-colliders into the #gamma#e and #gamma##gamma# colliders with approximately the same energies and luminosities was shown earlier. Their properties are compared from the point of view of possible physical investigations on them. 10 refs.; 1 tab.

CERN Document Server

Dusty primordial disks surrounding young low-mass stars are revealing tracers of stellar and planetary formation. The evolution and lifetime of these disks define the boundary conditions of the mechanisms of planet formation. Stellar companions, however, can significantly change this evolution through their tidal interactions. Stellar evolution and planet formation in binaries have to respond to an environment of truncated, quickly disappearing disks--very different compared to an isolated star environment. In order to investigate details of the influence of binarity on circumstellar disk evolution, we obtained adaptive optics supported near-infrared imaging and spectroscopy of the individual components of 22 low-mass binaries in the well-known Orion Nebula Cluster. Brackett gamma emission, which we detect in several systems, is used as a tracer for the presence of an active accretion disk around each binary component. We ...

CERN Document Server

We present an updated overview on the phenomenology of one-loop Higgs boson production at Linear Colliders within the general Two-Higgs-Doublet Model (2HDM). First we report on the Higgs boson pair production, and associated Higgs-Z boson production, at O(alpha^3_{ew}) from e+e- collisions. These channels furnish cross-sections in the range of 10-100 fb for Ecm=0.5 TeV and exhibit potentially large radiative corrections (of order 50%), whose origin can be traced back to the genuine enhancement capabilities of the triple Higgs boson self-interactions. Next we consider the loop-induced production of a single Higgs boson from direct gamma-gamma scattering. We single out sizable departures from the corresponding rates in the Standard Model, which are again correlated to trademark dynamical features of the 2HDM -- namely the balance of the non-standard Higgs/gauge, Higgs/fermion and Higgs self-interactions leading to sizable (destructive) ...

International Nuclear Information System (INIS)

We studied the dose-response effects of #gamma#-irradiation on the weight gains of the body and the brain in ICR mice exposed to various doses of "6"0Co #gamma#-irradiation ranging from 0 to 1.5 Gy on day 13 of pregnancy (E13). We found that 0.5 Gy #gamma#-irradiation caused a significant reduction in brain weight but not in body weight among 6-week-old mice. Higher doses (1.0, 1.5 Gy) seriously inhibited body and brain development, resulting in significantly low weights at 6 weeks of age. A significantly lower brain weight among fetuses exposed to 1.5 Gy was found as early as 24 hours after exposure, while significant reductions in the body weight of these same fetuses appeared 3 days after exposure. The effects of radiation on brain and body development were similar for both males and females. (author).

Energy Technology Data Exchange (ETDEWEB)

Nineteen-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) received a variable dose (0-40 Gy) from a cobalt-60 gamma source. A very sensitive stem monitoring device, developed at Battelle's Pacific Northwest Laboratories, Richland, Washington was used to measure real-time changes in stem diameter. Exposure of plants caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that nonreversible morphological growth changes could be induced by very low doses of radiation. Carbohydrate analysis of 40-Gy irradiated plants demonstrated significantly more starch content in leaves and significantly less starch content in stems 18 days after exposure than did control plants. In contrast, the carbohydrate content in roots of 40-Gy irradiated plants were not significantly different from unirradiated plants 18 days after exposure. These results ...

Energy Technology Data Exchange (ETDEWEB)

The estimation of radiation dose to man from either external or internal exposure to radionuclides requires a knowledge of the energies and intensities of the atomic and nuclear radiations emitted during the radioactive decay process. The availability of evaluated decay data for the large number of radionuclides of interest is thus of fundamental importance for radiation dosimetry. This handbook contains a compilation of decay data for approximately 500 radionuclides. These data constitute an evaluated data file constructed for use in the radiological assessment activities of the Technology Assessments Section of the Health and Safety Research Division at Oak Ridge National Laboratory. The radionuclides selected for this handbook include those occurring naturally in the environment, those of potential importance in routine or accidental releases from the nuclear fuel cycle, those of current interest in ...

International Nuclear Information System (INIS)

Estimations on the somatic and genetic effects of small doses of ionizing radiations in Man have been proposed by the Advisory Committee on the Biological Effects of Ionizing Radiation, set up by the U.S. National Academy of Sciences. They have been published in an important report, issued in 1972, from which we briefly analyze here the Chapter dealing with the somatic effects. Small doses of raditions are expected to promote only carcinogenic effects. After a rapid survey of the human experience on which the estimations are based, as regards the latent period of cancers, the plateau region (period of high risk) and the absolute and relative risk expressed per rem, per 10"6 persons, per year, for leukaemia (having the highest risk) and for the ''other cancers''. These estimations were obtained by linear extrapolation to the 1 rem level from observations made after irradiation at relatively high dose levels and much higher dose-rates. This ...

Energy Technology Data Exchange (ETDEWEB)

A theoretical model is developed to explain variations in airborne gamma-ray measurements over a calibration range near Ottawa, Ontario. The gamma-ray flux from potassium and the thorium decay series showed an expected decrease with increasing soil moisture. However, the gamma-ray flux from the uranium decay series was highest in the spring when the ground was water-saturated and even covered with snow. These results are explained through the build-up of radon and its associated gamma-ray-emitting decay products in the clay soil of the calibration range with increasing soil moisture. Similar results were found from airborne measurements over other clay soils. However, measurements over sandy soils showed that the count rates from all three radio elements increased with decreasing soil moisture. This difference between soil types was attributed to the lower radon emanation of the more coarse-grained ...

Energy Technology Data Exchange (ETDEWEB)

The young open cluster Berkeley 87 was predicted to be associated with the COS B {gamma}-ray source 2CG 075+00 on the basis of the experimental evidence of the presence of a shock front around the Wolf - Rayet star ST3 placed in the inner part of the cluster. The CGRO phase-1 data confirm this identification. Protons accelerated at the shock boundary can produce {pi} deg. via p-p interactions and then {gamma}-rays. With the measured flux F{sub {gamma}} (E > 100 MeV) {approx_equal} 9x10{sup -7} ph cm{sup -2} s{sup -1} and the power-law proton spectrum with spectral index {gamma} = 2, the cosmic-ray-energy-density in the inner part ({approx} 0.8 pc radius) of Berk 87 is about 100 times greater than that in the vicinity of the Earth. We have calculated {gamma}-ray spectra expected from the decay of {pi}{sup d}eg. produced in p-p interactions. The spectra have been normalized to ...

International Nuclear Information System (INIS)

In the future, the demand for energy is predicted to grow and more countries plan to utilize nuclear energy as their source of electric energy. This gives rise to many important issues connected to nuclear energy, such as finding methods that can verify that the spent nuclear fuel has been handled safely and used in ordinary power producing cycles as stated by the operators. Gamma ray spectroscopy is one method used for identification and verification of spent nuclear fuel. In the specific gamma ray spectroscopy method called gamma scanning the gamma radiation from the fission products Cs-137, Cs-134 and Eu-154 are measured in a spent fuel assembly. From the results, conclusions can be drawn about the fuels characteristics. This degree project examines the possibilities of using alternative measuring approaches when using the gamma scanning method. The focus is ...

Energy Technology Data Exchange (ETDEWEB)

It is anticipated that early in the next century manned missions into outer space will occur, with a mission to Mars scheduled between 2015 and 2020. However, before such missions can be undertaken, a realistic estimation of the potential risks to the flight crews is required. One of the uncertainties remaining in this risk estimation is that posed by the effects of exposure to the radiation environment of outer space. Although the composition of this environment is fairly well understood, the biological effects arising from exposure to it are not. The reasons for this are three-fold: (1) A small but highly significant component of the radiation spectrum in outer space consists of highly charged, high energy (HZE) particles which are not routinely experienced on earth, and for which there are insufficient data on biological effects; (2) Most studies on the biological effects of ...

International Nuclear Information System (INIS)

The author describes the Gamma -spectrum analysis results of "1"1"0"mAg, the method used, and the coincidence correction theory on which the analysis is based. The samples were placed at the upper end of the detector. The monitoring results of "1"1"0"mAg in the surrounding marine area from the beginning of operation of the Daya Bay nuclear power plant are reviewed as well. The results showed that "1"1"0"mAg traces were detected in some marine species. However, the concentrations observed are far below the National Standard limits

International Nuclear Information System (INIS)

Radioactive waste is generally classified on the basis of how much radiation and the type of radiation it emits as well as the length of time over which it will continue to emit radiation. Many activities dealing with radioactive materials produce nuclear wastes, including civilian nuclear power programs (nuclear Power plant operations and nuclear fuel-cycle activities), defense nuclear programs (nuclear weapons production, naval nuclear reactor programs, and related R and D), and industrial and institutional activities (scientific research, medical operations, and other industrial uses of Radioisotopic sources or Radio chemicals). To minimize the potential adverse health and environment impacts to people and other systems including of animals, plant and etc, during the entire lifetime of the radionuclides involved, nuclear waste must be carefully and properly managed. The scope of nuclear - waste ...

International Nuclear Information System (INIS)

GRR-1 is a 5MW open pool type research reactor with MTR-type fuel elements cooled and moderated by light water with beryllium reflectors at the two opposing sides of the core. A graphite thermal neutron column is adjusted to one side of the core. Six radial horizontal beam tubes are available, of which three contain in-pile collimators for neutron scattering instruments. The reactor is currently out of operation for inspection and refurbishment purposes. The core has been dismantled and the fuel elements are stored in the used fuel storage tank. The GRR-1 inspection and refurbishment plan involves inspection and eventually replacement of the reactor's primary cooling circuit. The health physics procedures to be implemented during inspection of the main water outlet are divided in three stages: a) pool dose rate survey from pool top, b) pool drainage by decreasing water level in steps and c) inspection of the water main outlet. urpose of the present work is the evaluation of the ...

Energy Technology Data Exchange (ETDEWEB)

The public expects that the Los Alamos National Laboratory (LANL) will operate in a manner that prevents negative impacts to the environment and protects the safety and health of its employees and the public. To achieve this goal within budget, the Department of Energy (DOE) and LANL must develop new and improved environment, safety, and health (ES and H) technologies and implement innovative, more cost-effective ES and H approaches to operations. In FY95, the Environment, Safety, and Health (ESH) Division initiated a Technology Development, Evaluation, and Application (TDEA) program. The purpose of this unique program is to test and develop technologies that solve LANL ES and H problems and improve the safety of LANL operations. This progress report presents the results of 10 projects funded in FY97 by the TDEA Committee of the Environment, Safety, and Health Division. Products generated from the ...

CERN Document Server

The principal paradigm for gamma-ray bursts (GRBs) suggests that the prompt transient gamma-ray signal arises from multiple shocks internal to the relativistic expansion. This paper explores how GRB prompt emission spectra can constrain electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The array of possible high-energy power-law indices in accelerated populations is highlighted, focusing on how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. When encompassing the MeV-band spectral break, fits to BATSE/EGRET burst data indicate that the preponderance of electrons responsible for the prompt emission reside in an intrinsically non-thermal population. This differs markedly from typical populations generated in acceleration simulations; potential resolutions of this conflict such as the action ...

CERN Document Server

The Zephyr Messaging Service for the NICE Environment

Energy Technology Data Exchange (ETDEWEB)

The mass generation in the Standard Model of Particles Physics relies on a spontaneous symmetry breaking mechanism. Its implementation is recalled, along with its constraints, both theoretical (Naturalness, Stability, Triviality, Unitarity) and experimental (limits of direct and indirect searches, prospects). Calculation techniques for observables evaluation in Perturbative Field Theory are described, particularly Helicity Amplitude method, which is given in details: fermions and vector bosons, massless and massive. Monte-Carlo integration, and structure functions approximations (which allows non-perturbative calculations) are also detailed. With these tools, a process giving to Physics beyond the Standard Model is studied: it leads to an experimental prediction for the LEP collision ring, taking the classical background into account. Technical aspects of a future photon linear collider are reviewed. The production of heavy vector bosons, either the classical Z for the hypothetical ...

Energy Technology Data Exchange (ETDEWEB)

The production of three vector bosons in {gamma} {gamma} collisions studying the reactions {gamma} + {gamma} {yields} W{sup +} + W{sup -} + Z{sup 0} and {gamma} + {gamma} {yields} W{sup +} + W{sup -} + {gamma}. 12 refs., 4 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

We estimate the TeV {gamma}-ray fluxes expected from the population of young pulsars in terms of the self-consistent time-dependent hadronic-leptonic model for the high-energy processes inside the pulsar wind nebulae (PWNe). This radiation model is based on the hypothesis of Arons and collaborators who postulate that leptons are accelerated inside the nebulae as a result of resonant scattering on heavy nuclei, which in turn are accelerated in the pulsar wind region or the pulsar inner magnetosphere. Our aim is to find out which PWNe on the northern hemisphere are the best candidates for detection at energies above 60 GeV and 200 GeV by the next generation of low-threshold Cherenkov telescopes.

Energy Technology Data Exchange (ETDEWEB)

The current status of rare B decays is reviewed based on recent observation of the penguin-diagram decay B {yields} K{sup *}{gamma} at CLEO. Rare B decays provide valuable information on the Standard Model parameters, and also could be a source of direct CP violation. It is emphasized that new physics beyond the Standard Model can appear in rare B decays, in some cases more drastically than in the CP Asymmetry of the B system. Inclusive measurement of the radiative transition b {yields} s{gamma} is promising. Hadronic penguin modes are very close to being observed at CLEO, and a discovery might be just around the corner. (author). 48 refs., 6 figs., 4 tabs.

International Nuclear Information System (INIS)

This study is an attempt to measure the quantities of elements in a composite by irradiating that composite with #gamma#-rays of various energies and detecting the transmitted radiation through the composite. A previous knowledge of the number of the elements and their attenuation coefficients is required. The quantities are calculated by solving the matrix of a linear system of equations. A computer program was developed to select the best combinations of the available energies. Five criteria were established to determine these energy combinations: (i) the determinant of the attenuation coefficient matrix; (ii) the condition number, (iii) the number of times the solution of the matrix leads to acceptable results; (iv) the indicator, (a new concept); (v) the standard deviations of the results. The intended application of this technique in medicine is to measure the bone mineral content of the skeleton. An examination of the error propagation, ...

Energy Technology Data Exchange (ETDEWEB)

A new method of determining the nuclear level density is presented. This method is based on the statistical analysis of the partial width fluctuations appearing in an excitation function of the radiative proton capture. The method was applied in the case of the /sup 88/Sr(p,..gamma..sub(..omega..))/sup 89/Y and /sup 89/Y(p,..gamma..sub(..omega..))/sup 90/Zr reactions. The density of levels with spin I/sup -/ in /sup 90/Zr and the densities of levels with spins 1/2/sup +/ and 3/2/sup +/ in /sup 89/Y at excitation energies from 10.9 to 11.6 MeV and from 9.3 to 10.8 MeV respectively, were determined with an uncertainty of about 35%.

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

British Library Electronic Table of Contents (United Kingdom)

Commercial polyolefin, such as poly(propylene), are widely used because of their easy processing and their excellent mechanical and thermal properties. Although their recycling is well established, the mechanical and thermal properties of the recycled waste poly(propylene)(WPP) are normally lower than those of the virgin material. The introduction of talc can improve the toughness, without compromising the processability and recycling capabilities. However, the thermal properties of these blends should be assessed to limit degradation during recycling. The effect of gamma radiation on the thermal and mechanical properties of WPP/High Crystallinity Poly(propylene)/Talc was studied. TGA, DSC, and electrical conductivity performed the characterization of WPP composites. Mechanical properties ...

Energy Technology Data Exchange (ETDEWEB)

Neutron capture ..gamma..-ray spectra have been measured at 11 average neutron energies from 10 to 530 keV in /sup 88/Sr using a 20 x 15 cm NaI detector with time-of-flight discrimination of background events. The partial radiation widths and the calculated partial valence widths are compared for the strong p-wave resonances at 287 and 321 keV and found to be highly correlated. At these energies, the spectra are dominated by strong transitions to low-lying single particle states, in confirmation of the role of valence capture in the 3p region. However, the data do not support this mechanism at <508> keV.

Energy Technology Data Exchange (ETDEWEB)

A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the U.S. Department of Energy's remedial action survey programs. The unit consists of NaI(Tl) detectors housed in a specially equipped van. The system is operator controlled through an on-board minicomputer with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided on floppy disk. Multichannel analysis capabilities are included for qualitative radionuclide identification. A /sup 226/Ra-specific algorithm is currently employed to identify locations containing residual radium-bearing materials.

International Nuclear Information System (INIS)

The most important factor in assessing radiologic risk is ensuring scientific means for evaluation of the radioactive release impact upon humans and organisms. To evaluate quantitatively this impact not only knowledge of radioactivity distribution in these dynamical systems is necessary but also understanding the transfer mechanisms between ecosystem components is needed. Thus a complete radioecologic study appear to be very complex and needs defining the source term, dynamic description of radionuclides behavior in the ecosystem, estimation of radiation doses in the major components of the ecosystem and finally the effects of radiation doses upon different parts of the systems. A diagram of the steps implied in evaluation of the effects due to radioactive effluent release in the environment is presented and discussed. The following steps are described: - identification of radioactive sources, as well as their input rate. ...

Energy Technology Data Exchange (ETDEWEB)

High energy physics facilities must monitor the radiation doses received by their personnel. This monitoring can only be effective if the radiation detection devices can be calibrated with a good degree of accuracy. Radiation fields are usually composed of several types of radiation, including gamma rays, beta radiation, neutrons, etc. The neutron detection instruments respond not only to the neutrons coming directly from the source but also those scattered from the floor, walls, and ceiling. The amount of neutron scattering varies from site to site depending on the construction materials and layout of the building. The purpose of this study was to determine the scattered neutron fraction in the central volume of the calibration mezzanine of the Radiation Physics Calibration Facility (RPCF) at the Fermi National Accelerator Laboratory ...

Energy Technology Data Exchange (ETDEWEB)

In this experiment, we measured the detection efficiency of gamma-scanning system of Irradiated Materials Examination Facility (IMEF) in Korea Atomic Energy Research Institute(KAERI) for the spent PWR fuel and activity known sources with high activity. We measured the absolute detection efficiency of gamma scanning system of IMEF to the {sup 137}Cs-source with 10.4 GBq and {sup 60}Co source with 25.9 GBq High-activity sources as standard sources, and a fuel burned in the KORI -1 reactor of the Kori Nuclear power plant. In analyzing, we used three peeks those were the 661.64 keV peak form {sup 137} Cs 1173.23 and 1332.51 keV{sup 60} Co sources, and 14 peaks of {sup 134}Cs and {sup 154}Eu on the spent fuel gamma spectrum which are in the energy range from 500 to 1,600 keV. We find second order equations for detection efficiency by using our experimental results. The equation show that the detection efficiency of ...

International Nuclear Information System (INIS)

This thesis reports investigations using gamma-radiation to decontaminate poultry carcasses. The application to foods of doses of ionizing radiation sufficient to reduce the number of viable specific non-sporeforming pathogenic microorganisms so that none is detectable in the treated food by any standard method is termed radicidation. The doses used in this study were at such a level that no undesirable or unfavourable side-effects occurred. The effects of these doses were studied on salmonellae and other microorganisms present in, or associated with poultry carcasses and in liquid and on solid culture media as well. Decimal reduction (D_1_0) values were estimated. These represent the dose (kGy) required to achieve a reduction in initial colony count from N_0 to 0.1 N_0. Together with the estimation of the numbers of Salmonella present per carcass the data were used to predict the effect of an ionizing radiation treatment ...

International Nuclear Information System (INIS)

The world fusion program has advanced to the stage where it is appropriate to construct a number of devices for the purpose of burning DT fuel. In these next-generation experiments, the expected flux and fluence of 14 MeV neutrons and associated gamma rays will pose a significant challenge to the operation and diagnostics of the fusion device. Radiation effects include structural damage to materials such as vacuum windows and seals, modifications to electrical properties such as electrical conductivity and dielectric strength and impaired optical properties such as reduced transparency and luminescence of windows and fiber optics during irradiation. In preparation for construction and operation of these new facilities, the fusion diagnostics community needs to work with materials scientists to develop a better understanding of radiation effects, and to undertake a testing program aimed at developing workable solutions for ...

International Nuclear Information System (INIS)

Radiation-and-thermal-combined degradation of some kinds of cable insulating and jacketing materials was evaluated by accelerated aging tests. Plasticized polyvinyl chloride (PVC), silicone rubber, crosslinked and non-crosslinked halogen-free flame-retardant polyolefins (NH-XLPO and NH-PO) and ethylene-propylene rubber (EP rubber) of experimental formulation were degraded at accelerated rates, that are 50-1000 times the degradation rate under standard conditions (e.g.; 1Gy/h, 50degC), and a method to assess the lifetime of these materials under standard conditions was studied. The degradation was investigated by measuring tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for these materials were in proportion to the increase in accelerated rate. The PVC lifetime estimated from sequential aging tests had a tendency to extend beyond that from simultaneous aging tests, while the lifetime of other materials estimated ...

Energy Technology Data Exchange (ETDEWEB)

The D2 antidopaminergic drug Domperidone was evaluated singly and in combination with synthetic adrenocorticoid and an H2 antihistamine for its ability to reduce the acute emetic effects of /sup 60/Co whole-body radiation. Random-source adult male dogs were fasted 12 hours, fed a standard meal, injected 44 minutes later and irradiated 47 minutes after that. Four groups of dogs were radiated after drug injections as follows: saline (Con), domperidone (Dom), cimetidine + thiethylperazine (Cim+Thi), and dexamethasone + domperidone + cimetidine (Dex+Dom+Cim). Drug quantities for dogs represented 10 mg Dom, 10 mg Thi, 20 mg Dex, and 300 mg Cim for an average human (70 ka, 1.8 m2). Subjects were exposed on an up-down schedule to determine the radiation necessary to produce vomiting in 50% (ED50) of each group. Emesis onset times, offset times, and number of episodes were recorded. The ED50 of Dex+Dom+Cim was higher than Con. Dom ...

International Nuclear Information System (INIS)

Beagle dogs were given single, whole-body "6"0Co gamma-radiation exposures at one of three prenatal (8, 28, or 55 days postcoitus) or three postnatal (2, 70, or 365 days postpartum) ages to evaluate the relative radiosensitivity of various stages of brain development. A total of 387 dogs received mean doses ranging from 0.16 to 3.83 Gy, and 120 dogs were sham-irradiated. Groups of dogs were sacrificed at preselected times from 70 days to 11 years of age. Brain weight decreased significantly with increasing dose in dogs irradiated at 28 or 55 days postcoitus or at 2 days postpartum. Irradiations at 28 days postcoitus were dramatically more effective in causing a reduction in brain weight than those at 55 days postcoitus or 2 days postpartum. Among dogs given 1.0 Gy or more and followed for up to 4 years, there was a radiation effect evident at all three sensitive exposure ages. Among dogs given lower doses and followed for up to 11 years, there ...

International Nuclear Information System (INIS)

Radiation sterilization has several merits that it is a positively effective sterilization method, it can be used to sterilize low heat-resistant containers and high gas barrier films, and there is no possibility of residual chemicals being left in the packages. It has been commercially used in 'Bag in a Box' and some food containers. The #gamma# ray and an electron beam are commonly used in radiation sterilization. The #gamma# ray can sterilize large size containers and containers with complex shapes or sealed containers due to its strong transmission capability. However, since the equipment tends to be large and expensive, it is generally used in off production lines. On the other hand, it is possible to install and electron beam system on food production lines since the food can be processed in a short time due to its high beam coefficient and its ease of maintenance, even though an electron beam has ...

Energy Technology Data Exchange (ETDEWEB)

Ford, Bacon, Davis Utah Inc. has reevaluated the Spook site in order to revise the December 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings 48 mi northeast of Casper, in Converse County, Wyoming. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 187,000 tons of tailings at the Spook site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.

International Nuclear Information System (INIS)

Wood-polymer composites (WPC) have been prepared of pinewood with different monomers using Gamma radiation: acrylamide, butyl acrylate, butyl methacrylate, styrene, acrylonitrile, and polyester. The polymer loading was determined as a function of monomer concentration and absorbed dose. The data show that polymer loading increases by increasing the monomer concentration. In two cases, BMA and polyester, the polymer loading decreases at high concentrations. This can be explained by the increase of the viscosity. Thus the diffusion of the compound into bulk would be slower. The absorbed dose seems to play a positive role in enhancing the polymer loading by increasing the dose. The mechanical properties, tensile and compression strength, have been improved in the most cases for all monomer concentrations or absorbed doses. Using polyester there was no improvement in the mechanical properties, and using acrylamide the improvement was at high ...

International Nuclear Information System (INIS)

A wood-polymer composite has been produced by impregnating the wood with the monomer and subsequently polymerizing it by exposure to a gamma radiation source. To compare the improvement in creep deformation of the wood due to the polymer impregnation, a nonlinear Norton-Bailey isothermal mathematical function has been used to model the bending creep deformation of the wood-polymer composites. Results show that the impregnation significantly improves the creep resistance of the wood. The maximum creep resistance is obtained when the amount of polymer impregnation exceeds about 30%. An interfacial interaction between the wood cell wall and the polymer could explain the creep deformation improvement, as well as the maximum impregnation level beyond which little improvement occurs. The results indicate that polymer impregnation is a viable method for improving the poor creep properties of wood. (author).

International Nuclear Information System (INIS)

The radiation induced reactions in LDPE in the presence of phenolic type antioxidants have been studied. It was shown that various antioxidants can influence the polyethylene network formation and the radical yield in different ways. The dependence of network structure on absorbed doses was determined by gel analysis, hot-set test and extraction of antioxidants for samples irradiated with accelerated electrons. It was found that the antioxidants eluted from polyethylene in higher percentage influence polymer crosslinking to a smaller degree. The ESR studies of #gamma#-irradiated blends of polyethylene with antioxidant indicate the presence of alkyl and phenoxyl radicals. The role of antioxidant molecules on radiation induced reactions in polyethylene-antioxidant systems is considered. The correlation between the network structure and the type of additive in polyethylene is also discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

Ford, Bacon and Davis Utah Inc. has reevaluated the Tuba City site in order to revise the March 1977 engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Tuba City, Arizona. This engineering assessment has included the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigations of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas released from the 0.8 million tons of tailings at the Tuba City site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation also are factors.