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Sample records for aciers austenitiques irradies

  1. Microstructural characterization and modeling of the hardening of irradiated austenitic steels from the internal structures of PWRs; Caracterisation microstructurale et modelisation du durcissement des aciers austenitiques irradies des structures internes des reacteurs a eau pressurisee

    Pokor, C.; Dubuisson, P. [CEA Saclay, DMN/SRMA, 91 - Gif-sur-Yvette (France); Massoud, J.P. [Electricite de France (EDF/MMC), 78 - Saint Moret sur Loing (France); Brechet, Y. [Institut Polytechnique de Grenoble, Lab. de Thermodynamique et de Physico Chimie Metallurgiques, CNRS, 38 (France); Barbu, A. [Ecole Polytechnique, Lab. des Solides Irradies, CEA / CNRS, 91 - Palaiseau (France)

    2002-07-01

    The screws and bolts of the lower internal structures of PWRs made of 316L cold-drawn austenitic steels is submitted to a neutron flux at a temperature comprised between 280 deg. C and 380 deg. C, which modifies their operation properties. These modifications of the mechanical properties are the consequence of the modifications of the microstructure of this steel which depends on the flux, fluence, reactor spectrum and irradiation temperature. Samples of 316L cold-drawn steels irradiated in a mixed flux reactor (Osiris at 330 deg. C between 0.8 dpa and 3.4 dpa) and in fast breeder reactors (Bor-60 at 330 deg. C up to 40 dpa and EBR-II at 375 deg. C up to 10 dpa) have been observed in transmission electron microscopy. Irradiation defects are Frank dislocation loops and the presence of cavities has been evidenced in materials irradiated at 375 deg. C. The evolution of the irradiation loops population has been modeled using an 'accumulation dynamics'-type simulation. The adjustment of the parameters of the model has permitted to describe quantitatively the experimental results. This description of the irradiation microstructure has been coupled with a Frank loops hardening model which has permitted to describe the observed hardening. The range of explored doses goes up to 40 dpa and is representative of the irradiation dose corresponding to the half life of the reactors design. (J.S.)

  2. Microstructural characterization and model of hardening for the irradiated austenitic stainless steels of the internals of pressurized water reactors; Caracterisation microstructurale et modelisation du durcissement des aciers austenitiques irradies des structures internes des reacteurs a eau pressurisee

    Pokor, C

    2003-07-01

    The core internals of Pressurized Water Reactors (PWR) are composed of SA 304 stainless steel plates and CW 316 stainless steel bolts. These internals undergo a neutron flux at a temperature between 280 deg C and 380 deg C which modifies their mechanical properties. These modifications are due to the changes in the microstructure of these materials under irradiation which depend on flux, dose and irradiation temperature. We have studied, by Transmission Electron Microscopy, the microstructure of stainless steels SA 304, CW 316 and CW 316Ti irradiated in a mixed flux reactor (OSIRIS at 330 deg C between 0,8 dpa et 3,4 dpa) and in a fast breeder reactor at 330 deg C (BOR-60) up to doses of 40 dpa. Moreover, samples have been irradiated at 375 deg C in a fast breeder reactor (EBR-II) up to doses of 10 dpa. The microstructure of the irradiated stainless steels consists in faulted Frank dislocation loops in the [111] planes of austenitic, with a Burgers vector of [111]. It is possible to find some voids in the solution annealed samples irradiated at 375 deg C. The evolution of the dislocations loops and voids has been simulated with a 'cluster dynamic' model. The fit of the model parameters has allowed us to have a quantitative description of our experimental results. This description of the microstructure after irradiation was coupled together with a hardening model by Frank loops that has permitted us to make a quantitative description of the hardening of SA 304, CW 316 and CW 316Ti stainless steels after irradiation at a certain dose, flux and temperature. The irradiation doses studied grow up to 90 dpa, dose of the end of life of PWR internals. (author)

  3. Behaviour comparison of various flux cored wires in FCAW on austenitic stainless steel; Comparaison du comportement de differents fils fourres en soudage MIG/MAG sur acier inoxydable austenitique

    Legoeuil, N. [Stagiaire/AREVA NP Tour AREVA, 92084 - Paris La Defense cedex, (France)

    2007-07-01

    This study deals with the GMAW process evaluation for the orbital butt welding of strong thickness pipings, in order to increase the productivity of these operations (higher deposition rate than in GTAW, process currently used). The main goal of this project is to evaluate the operational feasibility of mechanized orbital welding under gas protection in narrow gap with stainless flux cored wire 308L on stainless steel 304L. The study was composed of two parts with firstly a bibliographical research which has allowed to underline this operation practice, as good with rutile flux cored wire in smooth mode as with metal cored wire in pulsed mode. In the second part, flat and in position welding tests, by unit cords and filling of narrow grooves, made possible to define preliminary welding parameters. (author) [French] Cette etude s'inscrit dans le cadre de l'evaluation du procede MIG/MAG pour le soudage orbital bout a bout de tuyauteries de forte epaisseur, afin d'augmenter la productivite de ces operations (taux de depot plus eleve qu'en TIG, procede utilise actuellement). L'objectif du projet est d'evaluer la faisabilite operatoire du soudage orbital sous protection gazeuse en chanfrein etroit en mode mecanise avec fil fourre inoxydable 308L sur acier inoxydable 304L. L'etude s'est deroulee en deux parties avec dans un premier temps une recherche bibliographique qui a permis de mettre en evidence la pratique de cette operation, aussi bien avec des fils fourres rutiles en regime lisse qu'avec des fils fourres a poudre metallique en regime pulse. Dans un second temps, des essais de soudage a plat et en position, en cordons unitaires et en remplissage de chanfreins etroits, ont permis de definir des parametres preliminaires de soudage. (auteur)

  4. Elaboration de revêtements sur acier inoxydable: simulation de la fusion par irradiation laser, caractérisation structurale, mécanique et tribologique.

    Avril, Ludovic

    2003-01-01

    L'irradiation par un laser Nd-YAG pulsé est mise en oeuvre afin d'élaborer des revêtements épais sur acier inoxydable X30Cr13, par fusion superficielle avec apport de bore ou nitrure de bore hexagonal (h-BN): alliages borurés polyphasés ou composites métal-céramique. Les coupes métallographiques permettent de déterminer l'épaisseur de chaque revêtement (zone fondue) et révèlent des microstructures de solidification caractéristiques: front plan, cellulaire et dendritique. Les caractéristiques ...

  5. Experimental investigation of the residual stresses of 304L tubular welded joints; Caracterisation des contraintes residuelles sur assemblages soudes tubulaires en acier 304L

    Monin, L.; Panier, S.; Hariri, S.; Zakrzewski, D. [Ecole des Mines de Douai, 941, rue Charles Bourseul, BP 10838, 59508 DOUAI Cedex (France); Faidi, C. [EDF-SEPTEN, 12-14, avenue Dutrievoz, 69628 VILLEURBANNE (France)

    2007-07-01

    In the nuclear energy industry, the use of components made of austenitic stainless steel is widely spread, because of its specific thermal properties. The assembly of these pressure vessels and piping by welding processes often requires surface mechanical operations. These operations aim at hardening surfaces and lowering roughness. Nevertheless the main effect of these operations is the occurrence of residual stresses which can have positive or negative effects on the fatigue life. In this study, we focus on the evaluation and relaxation of residual stresses level on AISI 304L austenitic stainless steel tubular welded structures. Some of these rings are base metal rings (which stand as reference), the rest presents a longitudinal and symmetrical Y-weld joint, with or without grinding. Surface residual stresses, and their relaxation, were determined by using the X-ray diffraction method. (authors) [French] L'utilisation de composants en acier inoxydable austenitique, aux proprietes thermiques bien specifiques, est tres courante dans le domaine de la production d'energie nucleaire. Les procedes d'assemblage par soudage de ces equipements sous pression requierent des traitements de parachevement mecanique afin d'ameliorer l'etat de surface et modifier l'etat mecanique en introduisant des contraintes residuelles, qui peuvent avoir une influence sur la duree de vie de la structure. Cette etude porte sur la caracterisation et la relaxation des contraintes residuelles, determinees sur des eprouvettes annulaires specifiques en acier inoxydable austenitique de type 304L, a l'etat brut ou avec des soudures, arasees ou non. La methode de determination utilisee est la diffraction des rayons X. La relaxation de ces contraintes au cours d'essais de fatigue est egalement etudiee. (auteurs)

  6. Influence of localized deformation on A-286 austenitic stainless steel stress corrosion cracking in PWR primary water; Influence de la localisation de la deformation sur la corrosion sous contrainte de l'acier inoxydable austenitique A-286 en milieu primaire des REP

    Savoie, M

    2007-01-15

    Irradiation-assisted stress corrosion cracking (IASCC) of austenitic stainless steels is known to be a critical issue for structural components of nuclear reactor cores. The deformation of irradiated austenitic stainless steels is extremely heterogeneous and localized in deformation bands that may play a significant role in IASCC. In this study, an original approach is proposed to determine the influence of localized deformation on austenitic stainless steels SCC in simulated PWR primary water. The approach consists in (i) performing low cycle fatigue tests on austenitic stainless steel A-286 strengthened by {gamma}' precipitates Ni{sub 3}(Ti,Al) in order to shear and dissolve the precipitates in intense slip bands, leading to a localization of the deformation within and in (ii) assessing the influence of these {gamma}'-free localized deformation bands on A-286 SCC by means of comparative CERT tests performed on specimens with similar yield strength, containing or not {gamma}'-free localized deformation bands. Results show that strain localization significantly promotes A-286 SCC in simulated PWR primary water at 320 and 360 C. Moreover, A-286 is a precipitation-hardening austenitic stainless steel used for applications in light water reactors. The second objective of this work is to gain insights into the influence of heat treatment and metallurgical structure on A-286 SCC susceptibility in PWR primary water. The results obtained demonstrate a strong correlation between yield strength and SCC susceptibility of A-286 in PWR primary water at 320 and 360 C. (author)

  7. Thermal fatigue cracking of austenitic stainless steels; Fissuration en fatigue thermique des aciers inoxydables austenitiques

    Fissolo, A

    2001-07-01

    This report deals with the thermal fatigue cracking of austenitic stainless steels as AISI 316 LN and 304 L. Such damage has been clearly observed for some components used in Fast Breeder reactors (FBR) and Pressure Water Reactor (PWR). In order to investigate thermal fatigue, quasi-structural specimen have been used. In this frame, facilities enforcing temperature variations similar to those found under the operation conditions have been progressively developed. As for components, loading results from impeded dilatation. In the SPLASH facility, the purpose was to establish accurate crack initiation conditions in order to check the relevance of the usual component design methodology. The tested specimen is continuously heated by the passage of an electrical DC current, and submitted to cyclic thermal down shock (up to 1000 deg C/s) by means of periodical spraying of water on two opposite specimen faces. The number of cycles to crack initiation N{sub i} is deduced from periodic examinations of the quenched surfaces, by means of optical microscopy. It is considered that initiation occurs when at least one 50{mu}m to 150{open_square}m long crack is observed. Additional SPLASH tests were performed for N >> N{sub i}, with a view to investigate the evolution of a surface multiple cracking network with the number of cycles N. The CYTHIA test was mainly developed for the purpose of assessing crack growth dynamics of one isolated crack in thermal fatigue conditions. Specimens consist of thick walled tubes with a 1 mm circular groove is spark-machined at the specimen centre. During the test, the external wall of the tube is periodically heated by using a HF induction coil (1 MHz), while its internal wall is permanently cooled by flowing water. Total crack growth is derived from post-mortem examinations, whereby the thermal fatigue final rupture surface is oxidized at the end of the test. The specimen is broken afterwards under mechanical fatigue at room temperature. All the tests confirm that usual approaches are adapted in used conditions ( 280 {<=} T{sub max} {<=} 550 deg C, 100 {<=} {open_square}T {<=} 300 deg C): they are simply based on thermal loading mechanical loading equivalence. However, they appear not to be well adapted when additional factors exist such as roughness, residual stresses... Furthermore, Scanning Electron Microscopy observations show that damage is initiated well before the 'engineer initiation', as previously detected using optical microscopy on SPLASH specimen. First stage damage evolutions are thus a new task. Strain and stress fields generated during test are estimated thanks to finite element method computations (FEM), using CASTEM-2000 CEA software. Information coming from these FEM computations monitor lower-scale modelling: Discrete dislocation Dynamics (MICROMEGAS software). In order to continue that task, a new specimen has been adapted to the CYTHIA facility. Specimens consist of removable disks in which different and well-controlled conditions may be enforced. In order to estimate propagation of long crack, conventional fracture mechanic approach seems to be well adapted. The effective Stress Intensity Factor calculation takes into account of plastic strain. Furthermore, it is assumed that crack is opened during 60 % of cyclic loading. Shielding effect is clearly underlined by all the observations: on surface, on cross side section, and after sub-surface step-by-step removal. Multiple crack propagation (in the depth direction) is simulated using the previous single crack modelling. An auto-adaptative meshing allows simulating growth of 10 cracks up to 35,000 cycles. Two-development tasks are now in progress. The first task is oriented on the multiple crack growth and stability after an additional mechanical loading. The second task deals with the first damage stage up to the 'engineer crack initiation'. (author)

  8. Welding hot cracking in an austenitic stainless steel; Fissuration a chaud en soudage d'un acier inoxydable austenitique

    Kerrouault, N

    2001-07-01

    The occurrence of hot cracking is linked to several conditions, in particular, the composition of the material and the local strains due to clambering. The aim of this study is to better analyse the implied mechanisms and to lead to a local thermomechanical criterion for hot cracking. The example studied is an AISI 321-type stainless steel (X10CrNiTi18-12) strongly prone to cracking. Two weldability tests are studied: - the first one consists in carrying out a fusion line by the TIG process on a thin sheet. In the case of the defect occurrence, the crack is longitudinal and follows the back of the molten bath. The influence of the operating conditions welding (speed, welding heat input, width test sample) is studied. - the second one is the Varestraint test. It is widely used to evaluate the sensitivity of a material to hot cracking. It consists in loading the material by bending during a fusion line by the TIG process and in characterising the defects quantity (length, number). Various thermal and mechanical instrumentation methods were used. The possibilities of a local instrumentation instrumentation being limited because of the melting, the experimental results were complemented by a numerical modelling whose aim is to simulate the thermomechanical evolution of the loading thanks to the finite element analysis code ABAQUS. First, the heat input for thermal simulation is set by the use of an inverse method in order to optimise the energy deposit mode during welding in the calculation. Then, the mechanical simulation needs the input of a constitutive law that fits the mechanical behaviour over a wide temperature range from ambient to melting temperature. Thus, a mechanical characterization is performed by selecting strain values and strain rates representative of what the material undergoes during the tests. The results come from tensile and compressive tests and allow to settle an elasto-visco-plastic constitutive law over temperatures up to liquidus. Once validated, the thermomechanical simulation brings new interpretations of the tests observations and instrumentation results. The comparison of experimental and numerical results make it possible to determine a thermomechanical welding hot cracking criterion during solidification. This criterion simultaneously considers mechanical (strain and strain rates threshold) and thermal (temperature range, thermal gradient) parameters which give the position and orientation of the first crack initiation. The criterion precision are in good agreement with the observations on the two considered weldability tests. (author)

  9. Sub-micron indent induced plastic deformation in copper and irradiated steel; Deformation plastique induite par l'essai d'indentation submicronique, dans le cuivre et l'acier 316L irradie

    Robertson, Ch

    1999-07-01

    In this work we aim to study the indent induced plastic deformation. For this purpose, we have developed a new approach, whereby the indentation curves provides the mechanical behaviour, while the deformation mechanisms are observed thanks to Transmission Electron Microscopy (TEM). In order to better understand how an indent induced dislocation microstructure forms, numerical modeling of the indentation process at the scale of discrete dislocations has been worked out as well. Validation of this modeling has been performed through direct comparison of the computed microstructures with TEM micrographs of actual indents in pure Cu (001]. Irradiation induced modifications of mechanical behaviour of ion irradiated 316L have been investigated, thanks to the mentioned approach. An important hardening effect was reported from indentation data (about 50%), on helium irradiated 316L steel. TEM observations of the damage zone clearly show that this behaviour is associated with the presence of He bubbles. TEM observations of the indent induced plastic zone also showed that the extent of the plastic zone is strongly correlated with hardness, that is to say: harder materials gets a smaller plastic zone. These results thus clearly established that the selected procedure can reveal any irradiation induced hardening in sub-micron thick ion irradiated layers. The behaviour of krypton irradiated 316L steel is somewhat more puzzling. In one hand indeed, a strong correlation between the defect cluster size and densities on the irradiation temperature is observed in the 350 deg. C - 600 deg. C range, thanks to TEM observations of the damage zone. On the other hand, irradiation induced hardening reported from indentation data is relatively small (about 10%) and shows no dependence upon the irradiation temperature (within the mentioned range). In addition, it has been shown that the reported hardening vanishes following appropriate post-irradiation annealing, although most of the TEM

  10. Welding of super austenitic stainless steels with very high nitrogen contents; Soudabilite des aciers super austenitiques a tres fortes teneurs en azote

    Bonnefois, B.; Gagnepain, J.C.; Dupoiron, F.; Charles, J. [Societe des Forges et Ateliers du Creusot (SFAC), 75 - Paris (France)

    1995-12-31

    Results of studies performed on the weld of different super austenitic stainless steels show that nitrogen additions as high as 0.5% does not deteriorate the weldability but on the contrary improves the mechanical and corrosion properties of the weld. (A.B.). 5 refs., 5 figs., 6 tabs.

  11. Crack initiation at high temperature on an austenitic stainless steel; Amorcage de fissure a haute temperature dans un acier inoxydable austenitique

    Laiarinandrasana, L.

    1994-11-25

    The study deals with crack initiation at 600 and 650 degrees Celsius, on an austenitic stainless steel referenced by Z2 CND 17 12. The behaviour laws of the studied plate were update in comparison with existing data. Forty tests were carried out on CT specimens, with continuous fatigue with load or displacement controlled, pure creep, pure relaxation, creep-fatigue and creep-relaxation loadings. The practical initiation definition corresponds to a small crack growth of about the grain size. The time necessary for the crack to initiate is predicted with fracture mechanics global and local approaches, with the helps of microstructural observations and finite elements results. An identification of a `Paris`law` for continuous cyclic loading and of a unique correlation between the initiation time and C{sup *}{sub k} for creep tests was established. For the local approach, crack initiation by creep can be interpreted as the reaching of a critical damage level, by using a damage incremental rule. For creep-fatigue tests, crack growth rates at initiation are greater than those of Paris`law for continuous fatigue. A calculation of a transition time between elastic-plastic and creep domains shows that crack initiation can be interpreted whether by providing Paris`law with an acceleration term when the dwell period is less than the transition time, or by calculating a creep contribution which relies on C{sup *}{sub k} parameter when the dwell period and/or the initiation times are greater than the transition time. Creep relaxation tests present crack growth rates at initiation which are less than those for `equivalent` creep-fatigue tests. These crack growth rates when increasing hold time, but also when temperature decreases. Though, for hold times which are important enough and at lower temperature, there is no effect of the dwell period insofar as crack growth rate is equal to continuous fatigue Paris law predicted ones. (Abstract Truncated)

  12. Study of stress relief cracking in titanium stabilized austenitic stainless steel; Etude de la fissuration differee par relaxation d'un acier inoxydable austenitique stabilise au titane

    Chabaud-Reytier, M

    1999-07-01

    The heat affected zone (HAZ) of titanium stabilised austenitic stainless steel welds (AISI 321) may exhibit a serious form of intercrystalline cracking during service at high temperature. This type of cracking, called 'stress relief cracking', is known to be due to work hardening but also to ageing: a fine and abundant intragranular Ti(C,N) precipitation appears near the fusion line and modifies the mechanical behaviour of the HAZ. This study aims to better know the accused mechanism and to succeed in estimating the risk of such cracking in welded junctions of 321 stainless steel. To analyse this embrittlement mechanism, and to assess the lifetime of real components, different HAZ are simulated by heat treatments applied to the base material which is submitted to various cold rolling and ageing conditions in order to reproduce the HAZ microstructure. Then, we study the effects of work hardening and ageing on the titanium carbide precipitation, on the mechanical (tensile and creep) behaviour of the resulting material and on its stress relief cracking sensitivity. It is shown that work hardening is the main parameter of the mechanism and that ageing do not favour crack initiation although it leads to titanium carbide precipitation. The role of this precipitation is also discussed. Moreover, a creep damage model is identified by a local approach to fracture. Materials sensitive to stress relief cracking are selected. Then, creep tests are carried out on notched bars in order to quantify the intergranular damage of these different materials; afterwards, these measurements are combined with calculated mechanical fields. Finally, it is shown that the model gives good results to assess crack initiation for a compact tension (CT) specimen during relaxation tests, as well as for a notched tubular specimen tested at 600 deg. C under a steady torque. (author)

  13. Crack growth in an austenitic stainless steel at high temperature; Propagation de fissure a haute temperature dans un acier inoxydable austenitique

    Polvora, J.P

    1998-12-31

    This study deals with crack propagation at 650 deg C on an austenitic stainless steel referenced by Z2 CND 17-12 (316L(NN)). It is based on an experimental work concerning two different cracked specimens: CT specimens tested at 650 deg C in fatigue, creep and creep-fatigue with load controlled conditions (27 tests), tube specimens containing an internal circumferential crack tested in four points bending with displacement controlled conditions (10 tests). Using the fracture mechanics tools (K, J and C* parameters), the purpose here is to construct a methodology of calculation in order to predict the evolution of a crack with time for each loading condition using a fracture mechanics global approach. For both specimen types, crack growth is monitored by using a specific potential drop technique. In continuous fatigue, a material Paris law at 650 deg C is used to correlate crack growth rate with the stress intensity factor range corrected with a factor U(R) in order to take into account the effects of crack closure and loading ratio R. In pure creep on CT specimens, crack growth rate is correlated to the evolution of the C* parameter (evaluated experimentally) which can be estimated numerically with FEM calculations and analytically by using a simplified method based on a reference stress approach. A modeling of creep fatigue growth rate is obtained from a simple summation of the fatigue contribution and the creep contribution to the total crack growth. Good results are obtained when C* parameter is evaluated from the simplified expression C*{sub s}. Concerning the tube specimens tested in 4 point bending conditions, a simulation based on the actual A 16 French guide procedure proposed at CEA. (authors) 104 refs.

  14. Study of structural modifications induced by ion implantation in austenitic stainless steel; Etude des modifications structurales induites par implantation ionique dans les aciers austenitiques

    Dudognon, J

    2006-12-15

    Ion implantation in steels, although largely used to improve the properties of use, involves structural modifications of the surface layer, which remain still prone to controversies. Within this context, various elements (N, Ar, Cr, Mo, Ag, Xe and Pb) were implanted (with energies varying from 28 to 280 keV) in a 316LVM austenitic stainless steel. The implanted layer has a thickness limited to 80 nm and a maximum implanted element concentration lower than 10 % at. The analysis of the implanted layer by grazing incidence X ray diffraction highlights deformations of austenite lines, appearance of ferrite and amorphization of the layer. Ferritic phase which appears at the grain boundaries, whatever the implanted element, is formed above a given 'threshold' of energy (produced of fluency by the energy of an ion). The formation of ferrite as well as the amorphization of the implanted layer depends only on energy. In order to understand the deformations of austenite diffraction lines, a simulation model of these lines was elaborated. The model correctly describes the observed deformations (broadening, shift, splitting) with the assumption that the expansion of the austenitic lattice is due to the presence of implanted element and is proportional to the element concentration through a coefficient k'. This coefficient only depends on the element and varies linearly with its radius. (author)

  15. Comportement électrochimique d'un acier inoxydable sous rayonnement et en milieu représentatif des réacteurs à eau pressurisée (REPs).

    Wang, Mi

    2013-01-01

    Cette thèse est dédiée à l'étude du comportement des aciers inoxydables sous irradiation exposés en condition primaire des réacteurs à eau pressurisée (REP). Le potentiel électrochimique de l'acier inoxydable austénitique 316L et les paramètres environnementaux comme la teneur en hydrogène, ont été mesurés de façon continue à haute température (HT) et haute pression (HT) grâce à un dispositif expérimental unique, la cellule HTHP. Deux sources d'irradiation ont été utilisées: les protons et le...

  16. Plasticité cristaline des aciers sphéroïdisés et clivage

    Rezaee, Saeid

    2011-01-01

    La prédiction du clivage des aciers ferritiques a été largement étudiée à l’aide de l’approchelocale de la rupture, et des modèles macroscopiques identifiés phénoménologiquement comme celui de Beremin. Cette prédiction reste cependant difficile dans le domaine de transition ductilefragile. Cela a conduit à des études micromécaniques par les approches polycristallines afin de décrire l’évolution de la contrainte de clivage en fonction de la température pour les aciers bainitiques. Dans cette é...

  17. Formation mechanism of solute clusters under neutron irradiation in ferritic model alloys and in a reactor pressure vessel steel: clusters of defects; Mecanismes de fragilisation sous irradiation aux neutrons d'alliages modeles ferritiques et d'un acier de cuve: amas de defauts

    Meslin-Chiffon, E

    2007-11-15

    The embrittlement of reactor pressure vessel (RPV) under irradiation is partly due to the formation of point defects (PD) and solute clusters. The aim of this work was to gain more insight into the formation mechanisms of solute clusters in low copper ([Cu] = 0.1 wt%) FeCu and FeCuMnNi model alloys, in a copper free FeMnNi model alloy and in a low copper French RPV steel (16MND5). These materials were neutron-irradiated around 300 C in a test reactor. Solute clusters were characterized by tomographic atom probe whereas PD clusters were simulated with a rate theory numerical code calibrated under cascade damage conditions using transmission electron microscopy analysis. The confrontation between experiments and simulation reveals that a heterogeneous irradiation-induced solute precipitation/segregation probably occurs on PD clusters. (author)

  18. Atom probe study of the microstructural evolution induced by irradiation in Fe-Cu ferritic alloys and pressure vessel steels; Etude a la sonde atomique de l`evolution microstructurale sous irradiation d`alliages ferritiques Fe-Cu et d`aciers de cuve REP

    Pareige, P.

    1996-04-01

    Pressure vessel steels used in pressurized water reactors are low alloyed ferritic steels. They may be prone to hardening and embrittlement under neutron irradiation. The changes in mechanical properties are generally supposed to result from the formation of point defects, dislocation loops, voids and/or copper rich clusters. However, the real nature of the irradiation induced-damage in these steels has not been clearly identified yet. In order to improve our vision of this damage, we have characterized the microstructure of several steels and model alloys irradiated with electrons and neutrons. The study was performed with conventional and tomographic atom probes. The well known importance of the effects of copper upon pressure vessel steel embrittlement has led us to study Fe-Cu binary alloys. We have considered chemical aging as well as aging under electron and neutron irradiations. The resulting effects depend on whether electron or neutron irradiations ar used for thus. We carried out both kinds of irradiation concurrently so as to compare their effects. We have more particularly considered alloys with a low copper supersaturation representative of that met with the French vessel alloys (0.1% Cu). Then, we have examined steels used on French nuclear reactor pressure vessels. To characterize the microstructure of CHOOZ A steel and its evolution when exposed to neutrons, we have studied samples from the reactor surveillance program. The results achieved, especially the characterization of neutron-induced defects have been compared with those for another steel from the surveillance program of Dampierre 2. All the experiment results obtained on model and industrial steels have allowed us to consider an explanation of the way how the defects appear and grow, and to propose reasons for their influence upon steel embrittlement. (author). 3 appends.

  19. Source(s) of acoustic activity during pitting development on AISI 316L austenitic stainless steel; Source(s) de bruit acoustique dans le developpement de piqures sur acier inoxydable austenitique 316l

    Fregonese, M.; Idrissi, H.; Mazille, H. [Institut National des Sciences Appliquees, INSA, 69 - Villeurbanne (France); Renaud, L.; Cetre, Y. [Rhoditech, Materiaux-Corrosion, 69 - Decines-Charpieu (France)

    2001-07-01

    The acoustic emission (AE) technique, based on the rapid release of energy within a material generating a transient elastic wave propagation, is widely used as a non-destructive technique (NDT) for testing vessels on-site. Many microscopic deformation or fracture processes have also been studied with this technique in laboratory experiments, but most of them concerned stress corrosion cracking investigations. Some published papers also deal with abrasion or erosion corrosion studies, and only a few attempts have been made to study purely electrochemical corrosion types such as uniform corrosion or pitting corrosion. In the latter case, the studies mainly concern aluminium and austenitic stainless steels in the presence of chloride ions. In both cases, AE activity (number of events) has been correlated to the corrosion rate, which was estimated in terms of weight-loss, applied current density or hydrogen evolution rate. A direct quantitative correlation was even established between the number of AE events and the number of pits or the pitted area. Most of the time, the generation of acoustic signals has been attributed to the evolution of hydrogen bubbles. Yet, as no direct correlation was made between the formation and the release of bubbles and the generation of AE bursts, some other physico-chemical mechanisms were proposed, such as stress changes on metal surface, or the rupture of an oxide or salt cap covering the pits. Moreover, a thorough investigation has been performed by Arora in various well-controlled experimental conditions on aluminium alloys. As mentioned by the author, if AE has to be used for detecting and identifying an active corrosion process such as pitting, it is absolutely necessary to proceed to careful acoustic parameters analyses of recorded AE signals. In that sense, the authors recently reported that two kinds of AE signals were recorded during pitting corrosion investigations, which could be discriminated by their rise time and counts number, whether pits are initiated by potential or current application on specimens machined out from a bar or from a rolled sheet. Further more, a correlation between emissivity and sensitivity of the material towards pitting, evaluated in terms of time delay and acoustic rate, was established. Yet, the size of the pits does not seem to be discriminative for emissivity: resonant signals are only recorded during the development of the pits as occluded cells. In that context, if different mechanisms have been proposed to be responsible for the emission of acoustic signals during pitting corrosion, no comparative study of individual physico-chemical phenomena occurring at the bottom of the pit has been carried out. This is the aim of this work. (authors)

  20. Modelling of microstructural creep damage in welded joints of 316L stainless steel; Modelisation de l'endommagement a haute temperature dans le metal d'apport des joints soudes d'acier inoxydable austenitique

    Bouche, G

    2000-07-01

    Welded joints of 316L stainless steel under service conditions at elevated temperature are known to be preferential sites of creep damage, as compared to the base material. This damage results in the formation of cavities and the development of creep cracks which can lead to a premature failure of welded components. The complex two-phase microstructure of 316L welds was simulated by manually filling a mould with longitudinal deposited weld beads. The moulded material was then aged during 2000 hours at 600 deg. C. High resolution Scanning Electron Microscopy was largely used to examine the microstructure of the simulated material before and after ageing. Smooth and notched creep specimens were cut from the mould and tested at 600 deg. C under various stress levels. A comparison of the lifetime versus nominal stress curves for the base and welded materials shows a greater dependence of the welded material to creep phenomena. Observation and EBSD analysis show that damage is preferentially located along the austenite grain boundaries. The stress and strain fields in the notched specimens were calculated by finite element method. A correlation of this field to the observed damage was made in order to propose a predictive law relating the creep damage to the mechanical conditions applied locally. Further mechanical tests and simulation on CT specimens and mode II tubular specimens allowed validating the model under various multiaxial loading conditions. (author)

  1. Benefic effects of high nitrogen contents on properties of super austenitic stainless steels for very severe corrosive applications; Interet des fortes teneurs en azote sur les proprietes d`aciers inoxydables super austenitiques pour corrosion severe

    Gagnepain, J.C.; Chavet, M.; Verneau, M.; Dupoiron, F.; Charles, J. [Societe des Forges et Ateliers du Creusot (SFAC), 75 - Paris (France)

    1995-12-31

    New highly allowed austenitic stainless steels (PREN included in the 40/60 range) have been investigated. The effects of allowing elements on mechanical properties, structure stability and corrosion resistance have been defined. As a result, we determine the best equilibria for structure stability and corrosion resistance: the tungsten additions are particularly interesting, since this element, as molybdenum, increases the localised corrosion resistance but presents a lower segregation rate than molybdenum (what is very important for manufacturing heavy plates or bars). This study made us optimize the chemical analysis of a new high nitrogen, high strength, super austenitic stainless steel (URANUS B 66), the properties of which will be described in this paper. (authors). 5 refs., 11 figs., 4 tabs.

  2. Local approach: fracture at high temperature in an austenitic stainless steel submitted to thermomechanical loadings. Calculations and experimental validations; Approche locale: fissuration a haute temperature dans un acier inoxydable austenitique sous chargements thermomecaniques. Simulations numeriques et validations experimentales

    Poquillon, D

    1997-10-01

    Usually, for the integrity assessment of defective components, well established rules are used: global approach to fracture. A more fundamental way to deal with these problems is based on the local approach to fracture. In this study, we choose this way and we perform numerical simulations of intergranular crack initiation and intergranular crack propagation. This type of damage can be find in components of fast breeder reactors in 316 L austenitic stainless steel which operate at high temperatures. This study deals with methods coupling partly the behaviour and the damage for crack growth in specimens submitted to various thermomechanical loadings. A new numerical method based on finite element computations and a damage model relying on quantitative observations of grain boundary damage is proposed. Numerical results of crack initiation and growth are compared with a number of experimental data obtained in previous studies. Creep and creep-fatigue crack growth are studied. Various specimen geometries are considered: compact Tension Specimens and axisymmetric notched bars tested under isothermal (600 deg C) conditions and tubular structures containing a circumferential notch tested under thermal shock. Adaptative re-meshing technique and/or node release technique are used and compared. In order to broaden our knowledge on stress triaxiality effects on creep intergranular damage, new experiments are defined and conducted on sharply notched tubular specimens in torsion. These isothermal (600 deg C) Mode II creep tests reveal severe intergranular damage and creep crack initiation. Calculated damage fields at the crack tip are compared with the experimental observations. The good agreement between calculations and experimental data shows the damage criterion used can improve the accuracy of life prediction of components submitted to intergranular creep damage. (author) 200 refs.

  3. Influence of nitrogen on the stress corrosion cracking resistance of austenitic stainless steels in chloride environment; Influence de l'azote sur la resistance a la corrosion sous contrainte d'aciers inoxydables austenitiques en milieu chlorure

    Teysseyre, S

    2001-11-01

    The aim of this study is to investigate the influence of nitrogen additions on the Stress Corrosion Cracking (SSC) resistance of austenitic stainless steel in chloride environment. The investigation was carried out in two part: first, an experimental investigation with model industrial steels was carried out and secondly, numerical simulations based on the Corrosion Enhanced Plasticity Model were developed. Both slow strain rate tensile tests and constant load test of the different steels in boiling MgCl{sub 2} (153 deg C) at free potential show that, for a given plastic strain rate, nitrogen addition increases the critical stress for crack initiation without influencing the crack propagation rate. We observed that the creep rate under constant load was affected by the nitrogen content. As a consequence, the SCC behaviour (cracks density and propagation rate) depends on the nitrogen content. We thus confirm that the nitrogen content influences the corrosion - deformation interaction mechanisms via its positive contribution to the flow stress. These experimental results are reproduced semi-quantitatively by means of numerical simulations at the scale of crack. - dislocation interactions. The presence of nitrogen is modelled by an increased lattice friction stress, which in turn affects the dynamics of crack tip shielding by dislocation pile-ups. We conclude that nitrogen addition in austenitic stainless steels increases the SC crack initiation stress in proportion of the increased flow stress, without penalty in terms of SC crack propagation rate. (author)

  4. Low cycle fatigue: high cycle fatigue damage accumulation in a 304L austenitic stainless steel; Endommagement et cumul de dommage en fatigue dans le domaine de l'endurance limitee d'un acier inoxydable austenitique 304L

    Lehericy, Y

    2007-05-15

    The aim of this study was to evaluate the consequences of a Low Cycle Fatigue pre-damage on the subsequent fatigue limit of a 304L stainless steel. The effects of hardening and severe roughness (grinding) have also been investigated. In a first set of tests, the evolution of the surface damage induced by the different LCF pre-cycling was characterized. This has permitted to identify mechanisms and kinetics of damage in the plastic domain for different surface conditions. Then, pre-damaged samples were tested in the High Cycle Fatigue domain in order to establish the fatigue limits associated with each level of pre-damage. Results evidence that, in the case of polished samples, an important number of cycles is required to initiate surface cracks ant then to affect the fatigue limit of the material but, in the case of ground samples, a few number of cycles is sufficient to initiate cracks and to critically decrease the fatigue limit. The fatigue limit of pre-damaged samples can be estimated using the stress intensity factor threshold. Moreover, this detrimental effect of severe surface conditions is enhanced when fatigue tests are performed under a positive mean stress (author)

  5. Reheat cracking of austenitic stainless steels - pre-strain effect on intergranular damage; Fissuration en relaxation des aciers inoxydables austenitiques - influence de l'ecrouissage sur l'endommagement intergranulaire

    Auzoux, Q

    2004-01-01

    Welding process induces strain in 316 stainless steel affected zones. Their microstructure was reproduce by rolling of three different steels (316L, 316L(N) et 316H). Traction, creep and relaxation tests were performed at 550 deg C and 600 deg C on smooth, notched and pre-cracked specimens. Pre-strain by rolling increases the hardness and the creep resistance because of the high dislocation density but decreases ductility because of the fast development of intergranular damage. This embrittlement leads to crack propagation during relaxation tests on pre-strained steels without distinction in respect to their carbon or nitrogen content. A new intergranular damage model was built using local micro-cracks measurements and finite elements analysis. Pre-strain effect and stress triaxiality ratio effect are reproduced by the modelling so that the reheat cracking risk near welds can now be estimated. (author)

  6. SOUDAGE D'ACIER Z 2 CN 18-10 PAR LASER CO2

    Petesch, B.; SAKOUT, A; Laurent, M.; M. Robin

    1987-01-01

    Le soudage d'un acier Z 2 CN 18 par faisceau laser a été étudié. L'influence principaux paramètres vitesse, puissance, focalisation a été examinée. Les moyens classiques de caractérisation des soudures ont été utilisées : observations métallographiques forme de la zone fondue, quantité de porosités et énergie absorbée. Le maximum de pénétration correspond au maximum d'énergie absorbée.

  7. Modélisation Elasto-Viscoplastique du Comportement des Aciers

    PIPARD, Jean-Marc; ABED-MERAIM, Farid; BALAN, Tudor; Berveiller, Marcel; Bouaziz, Olivier; LEMOINE, Xavier

    2007-01-01

    Dans cet article, une modélisation des différentes phases (ferrite, perlite etc.…) d’un acier multiphasé est proposée moyennant une loi phénoménologique à base physique. La description unifiée du comportement viscoplastique peut être décrite à partir de lois de type sinus hyperbolique. Dans cette optique, une loi en sinus hyperbolique est utilisée afin de décrire de façon physiquement acceptable l’ensemble des comportements asymptotiques du comportement viscoplastique. L’écrouissage de chacun...

  8. Aciers inoxydables et corrosion localisée : le rôle du molibdène

    Mesquita, Thiago

    2012-01-01

    Les aciers inoxydables sont de plus en plus utilisés comme renfort du béton dans lesconstructions marines et côtières, afin de prévenir la corrosion induite par les ions chloruresqui pénètrent dans le béton poreux. L’ajout de molybdène dans les aciers inox contribue àaugmenter leur résistance à la corrosion par piqure lorsqu’ils sont utilisés dans desenvironnements acides et neutres. Cependant, le rôle du Mo sur la corrosion par piqûre desaciers en milieu alcalin chloruré reste à ce jour flou...

  9. FATIGUE PAR CHOCS - DISPOSITIF EXPÉRIMENTAL - RÉSULTATS OBTENUS SUR UN ACIER AU NICKEL-CHROME-MOLYBDÈNE

    Bousseau, M.; Clisson, J.; Mas, Ch.

    1985-01-01

    Un dispositif expérimental basé sur le principe des barres d'Hopkinson a été développé afin d'étudier le comportement en fatigue par chocs d'éprouvettes de traction. Les possibilités et les limites sont présentées ainsi que les premiers résultats obtenus sur un acier 35 NCD 16.

  10. Fragilisation par le zinc liquide des aciers haute résistance pour l'automobile Liquid zinc embrittlement of high strength automotive steels

    Frappier Renaud; Paillard Pascal; Gall René Le; Dupuy Thomas; Fabregue Damien; Kleber Xavier

    2013-01-01

    Cette étude présente les investigations menées sur la fragilisation par le zinc liquide d'un acier électro-zingué. La caractérisation mécanique par essais de traction à haute température montre un important puits de ductilité entre environ 700 ∘C et environ 950 ∘C. L'observation au MEB des éprouvettes de traction indique que, dans la gamme de température observée pour laquelle il y a fragilisation, on a mouillage intergranulaire des joints de grains de l'acier à l'interface acier/revêtement p...

  11. Valorisation des laitiers issus de l'élaboration d'aciers inoxydables dans le béton

    Adegoloye, Obafèmi Gildas Franck

    2014-01-01

    Le laitier EAF inox et le laitier AOD sont les deux principaux laitiers issus de l'élaboration des aciers inoxydables. Aujourd'hui ces laitiers ne sont valorisés qu'en construction routière. Cette utilisation ne permet pas d'assurer une valorisation complète et pérenne de ces laitiers dont une large part reste stockée. Compte tenu des propriétés physiques des laitiers EAF inox et AOD solidifié par stabilisation, leur utilisation comme granulats dans le béton peut être intéressante. L'objectif...

  12. Influence de la composition chimique et de la microstructure sur le dégazage de l'hydrogène des aciers inoxydables austénitiques destinés à l'ultravide

    Reinert, Marie-Pierre

    Dans les installations métalliques sous ultravide, l'hydrogène est le principal constituant de l'atmosphère résiduelle. Le flux de dégazage d'une tôle en acier inoxydable austénitique, matériau fréquemment utilisé en technologie du vide, après un étuvage sous vide, est typiquement de quelques 10-12 Torr.1/cm2.s, et est constitué principalement d'hydrogène. Dans le cadre de cette étude, un appareillage de thermodésorption sous ultravide a été conçu et mis au point pour étudier les phénomènes d'adsorption, de diffusion et de piégeage de l'hydrogène résiduel dans les aciers inoxydables austénitiques. Différents aciers ont été étudiés: l'acier 316L (avec trois modes d'élaboration différents), l'acier 316LN et d'autres aciers stabilisés au titane ou au niobium. La microstructure et la couche d'oxyde de ces aciers ont été caractérisées à l'état de réception et pendant les cycles de thermodésorption. Pendant un cycle de thermodésorption, les principales espèces désorbées...

  13. Fissuration en relaxation des aciers inoxydables austénitiques au voisinage des soudures

    Auzoux, Q.; Allais, L.; Gourgues, A. F.; Pineau, A.

    2003-03-01

    Des fissures intergranulaires peuvent se développer au voisinage des soudures des aciers inoxydables austénitiques lorsqu'ils sont réchauffés dans le domaine de température compris entre 500^{circ}C et 700^{circ}C. A ces températures, les contraintes résiduelles post-soudage se relaxent par déformation viscoplastique. Il peut arriver que ces zones proches de la soudure soient tellement fragiles, qu'elles ne puissent accommoder cette faible déformation. Afin de préciser quelles peuvent être les modifications microstructurales qui conduisent à une telle fragilisation, on a examiné les microstructures de ces zones et révélé ainsi un écrouissage résiduel, responsable d'une forte élévation de la dureté. On a pu reproduire par hypertrempe puis laminage entre 400^{circ}C et 600^{circ}C une microstructure similaire. Des essais mécaniques (traction, fluage, relaxation, sur éprouvettes lisses et pré-fissurées) ont été réalisés à 550^{circ}C et à 600^{circ}C sur ces zones affectées simulées et sur un état de référence hypertrempé. Ils ont montré que l'écrouissage diminuait la ductilité dans le domaine de rupture intergranulaire, sans modifier qualitativement le mécanisme d'endommagement. Pendant la pré-déformation les incompatibilités de déformation entre grains conduiraient à l'existence de contraintes locales élevées qui favoriseraient la germination des cavités intergranulaires.

  14. Caractérisation mécanique multi-échelle des produits de corrosion d’aciers doux

    Dehoux, A; Berthaud, Y; BOUCHELAGHEM, F.

    2011-01-01

    Cette étude vise à déterminer le comportement mécanique des produits qui se créent lors de la corrosion des armatures du béton armé. Dans ce cadre une caractérisation complète de la microstructure d'échantillons de corrosion d'acier doux ainsi que des calculs d'homogénéisation ont été réalisés. En parallèle, des essais de traction-compression ont été faits au MEB in situ et ont permis de mettre en relation calculs d'homogénéisation et comportement réel des échantillons....

  15. Initiation and growth of thermal fatigue crack networks in an AISI 304 L type austenitic stainless steel (X2 CrNi18-09); Amorcage et propagation de reseaux de fissures de fatigue thermique dans un acier inoxydable austenitique de type X2 CrNi18-09 (AISI 304 L)

    Maillot, V

    2004-07-01

    We studied the behaviour of a 304 L type austenitic stainless steel submitted to thermal fatigue. Using the SPLASH equipment of CEA/SRMA we tested parallelepipedal specimens on two sides: the specimens are continuously heated by Joule effect, while two opposites faces are cyclically. cooled by a mixed spray of distilled water and compressed air. This device allows the reproduction and the study of crack networks similar to those observed in nuclear power plants, on the inner side of circuits fatigued by mixed pressurized water flows at different temperatures. The crack initiation and the network constitution at the surface were observed under different thermal conditions (Tmax = 320 deg C, {delta}T between 125 and 200 deg C). The experiment produced a stress gradient in the specimen, and due to this gradient, the in-depth growth of the cracks finally stopped. The obtained crack networks were studied quantitatively by image analysis, and different parameters were studied: at the surface during the cycling, and post mortem by step-by-step layer removal by grinding. The maximal depth obtained experimentally, 2.5 mm, is relatively coherent with the finite element modelling of the SPLASH test, in which compressive stresses appear at a depth of 2 mm. Some of the crack networks obtained by thermal fatigue were also tested in isothermal fatigue crack growth under 4-point bending, at imposed load. The mechanisms of the crack selection, and the appearance of the dominating crack are described. Compared to the propagation of a single crack, the crack networks delay the propagation, depending on the severity of the crack competition for domination. The dominating crack can be at the network periphery, in that case it is not as shielded by its neighbours as a crack located in the center of the network. It can also be a straight crack surrounded by more sinuous neighbours. Indeed, on sinuous cracks, the loading is not the same all along the crack path, leading to some morphological effect instead of shielding effect. A 2-D finite element modelling of multiple crack propagation has been performed: when the morphological effects are not dominant, there is a good agreement between modelling and experimental results. (author)

  16. Stress corrosion of austenitic steels mono and polycrystals in Mg Cl{sub 2} medium: micro fractography and study of behaviour improvements; Corrosion sous contrainte de mono et polycristaux d`aciers inoxydables austenitiques en milieu MgCI{sub 2}: analyse microfractographique et recherche d`ameliorations du comportement

    Chambreuil-Paret, A

    1997-09-19

    The austenitic steels in a hot chlorinated medium present a rupture which is macroscopically fragile, discontinuous and formed with crystallographic facets. The interpretation of these facies crystallographic character is a key for the understanding of the stress corrosion damages. The first aim of this work is then to study into details the micro fractography of 316 L steels mono and polycrystals. Two types of rupture are observed: a very fragile rupture which stresses on the possibility of the interatomic bonds weakening by the corrosive medium Mg Cl{sub 2} and a discontinuous rupture (at the micron scale) on the sliding planes which is in good agreement with the corrosion enhanced plasticity model. The second aim of this work is to search for controlling the stress corrosion by the mean of a pre-strain hardening. Two types of pre-strain hardening have been tested. A pre-strain hardening with a monotonic strain is negative. Indeed, the first cracks starts very early and the cracks propagation velocity is increased. This is explained by the corrosion enhanced plasticity model through the intensifying of the local corrosion-deformation interactions. On the other hand, a cyclic pre-strain hardening is particularly favourable. The first micro strains starts later and the strain on breaking point levels are increased. The delay of the starting of the first strains is explained by a surface distortion structure which is very homogeneous. At last, the dislocations structure created in fatigue at saturation is a planar structure of low energy which reduces the corrosion-deformation interactions, source of micro strains. (O.M.) 139 refs.

  17. A three dimensional discrete dislocation dynamics modelling of the early cycles of fatigue in an austenitic stainless steel 316L: dislocation microstructure and damage analysis; Modelisation physique des stades precurseurs de l'endommagement en fatigue dans l'acier inoxydable austenitique 316L

    Depres, Ch

    2005-07-01

    A numerical code modelling the collective behaviour of dislocations at a mesoscopic scale (Discrete Dislocation Dynamics code) is used to analyse the cyclic plasticity that occurs in surface grains of an AISI 316L stainless steel, in order to understand the plastic mechanism involved in crack initiation in fatigue. Firstly, the analyses of both the formation and the evolution of the dislocation microstructures show the crucial role of cross-slip played in the strain localization in the form of slip bands. As the cycling proceeds, the slip bands exhibit well-organized dislocation arrangements that substitute to dislocation tangles, involving specific interaction mechanisms between primary and deviate systems. Secondly, both the surface displacements generated by plastic slip and the distortion energy induced by the dislocation microstructure have been analysed. We find that an irreversible surface relief in the form of extrusion/intrusion can be induced by cyclic slip of dislocations. The number of cycles for the crack initiation follows a Manson-Coffin type law. The analyses of the concentration of the distortion energy and its repartition in the slip bands show that beneficial energetic zones may be present at the very beginning of the cycling, and that mode-II crack propagation in the surface grains results from a succession of micro-crack initiations along primary slip plane, which is facilitated by various effects (stress concentration due to surface relief, environment effects...). Finally, a dislocation-based model for cyclic plasticity is proposed from Discrete Dislocation Dynamics results. (author)

  18. Thermal fatigue of a 304L austenitic stainless steel: simulation of the initiation and of the propagation of the short cracks in isothermal and aniso-thermal fatigue; Fatigue thermique d'un acier inoxydable austenitique 304L: simulation de l'amorcage et de la croissance des fissures courtes en fatigue isotherme et anisotherme

    Haddar, N

    2003-04-01

    The elbow pipes of thermal plants cooling systems are submitted to thermal variations of short range and of variable frequency. These variations bound to temperature changes of the fluids present a risk of cracks and leakages. In order to solve this problem, EDF has started the 'CRECO RNE 808' plan: 'thermal fatigue of 304L austenitic stainless steels' to study experimentally on a volume part, the initiation and the beginning of the propagation of cracks in thermal fatigue on austenitic stainless steels. The aim of this study is more particularly to compare the behaviour and the damage of the material in mechanic-thermal fatigue (cycling in temperature and cycling in deformation) and in isothermal fatigue (the utmost conditions have been determined by EDF for the metal: Tmax = 165 degrees C and Tmin = 90 degrees C; the frequency of the thermal variations can reach a Hertz). A lot of experimental results are given. A model of lifetime is introduced and validated. (O.M.)

  19. Influence des conditions de soudage sur le comportement en fatigue d'un acier THR Dual Phase soudé par point

    Rossillon, Frédérique

    2007-01-01

    Les principaux modèles de comportement en fatigue des assemblages soudés par point ne prennent en compte que des paramètres géométriques. Or, les contraintes résiduelles, la microstructure de la Zone Affectée Thermiquement et la forme du fond d'entaille sont, a priori, autant de facteurs d'influence supplémentaires. L'objectif de ce travail est la compréhension des facteurs prédominants de la tenue en fatigue des assemblages soudés par point en acier THR, afin de proposer des conditions de so...

  20. Etude de la corrosion des aciers de précontrainte dans des milieux cimentaires et en solutions synthètiques

    BLACTOT, E; BRUNET VOGEL, C; FARCAS, F; Gaillet, L.; MABILLE, I; Chaussadent, T.; Sutter, E

    2007-01-01

    La durabilité des ouvrages en béton précontraint est directement liée à la longévité des câbles en acier sous contrainte. De nombreux problèmes pouvant altérer la pérennité des ouvrages ont été identifiés tel que la rupture de câbles due à la corrosion sous contrainte. Dans cet article, il a été considéré le cas d'un défaut d'injection de coulis de ciment destinée à protéger les câbles. Dans ce cas, la présence de zones dégradées (zone ségrégée et ressuée) au contact de l'acier peut entraîner...

  1. Simulation multi-échelle du skin-pass des aciers IF : Prédiction de la texture de déformation et du comportement mécanique

    SOHO, Komi; LEMOINE, Xavier; Abed-Meraim, Farid; ZAHROUNI, Hamid

    2015-01-01

    L’objectif principal de cette étude est de prédire la texture la texture de déformation et le comportement mécanique des aciers IF au cours du procédé de laminage des produits plats à faible taux de réduction. Un modèle basé sur l’homogénéisation autocohérente du comportement élastoplastique du monocristal est adopté pour modéliser le comportement de l’acier. Afin de réduire les temps de calcul dans la simulation multi-échelle, une procédure simplifiée est adoptée pour coupler le code de simu...

  2. Étude de l’influence des paramètres de soudage sur la microstructure et le comportement mécanique des assemblages acier-aluminium obtenus par soudage à l’arc MIG-CMT.

    Mezrag, Bachir

    2015-01-01

    Les assemblages acier-aluminium de tôles minces (0,8 à 2 mm) ont été beaucoup étudiés au début des années 2000 pour desapplications automobiles, dans la perspective d’alléger les véhicules (projet européen Super Light Car). Dans ce contexte, le présenttravail est réalisé en vue d’étudier les possibilités d’assemblage hétérogène acier-aluminium par la nouvelle variante du procédé desoudage MIG connue sous l’appellation CMT (Cold Metal Transfer). La première partie de l’étude est consacrée à la...

  3. Évolution des contraintes résiduelles dans la couche de diffusion d’un acier modèle Fe-Cr-C nitruré

    Jegou, Sébastien; Barrallier, Laurent; Somers, Marcel A. J.

    2011-01-01

    Limiter la fatigue et la corrosion des pièces est possible grâce à une nitruration. Des contraintes résiduelles en découlent. Le rôle de la diffusion du carbone sur le développement de ces contraintes a été étudié sur un acier modèle Fe-3%m.Cr-0.35%m.C.......Limiter la fatigue et la corrosion des pièces est possible grâce à une nitruration. Des contraintes résiduelles en découlent. Le rôle de la diffusion du carbone sur le développement de ces contraintes a été étudié sur un acier modèle Fe-3%m.Cr-0.35%m.C....

  4. Analyse statistique de l'assemblage acier/aluminium réalisé par le procédé de soudage MIG-CMT

    Mezrag, Bachir; Benachour, Mustapha; Deschaux Beaume, Frédéric

    2014-01-01

    La dépendance vis-à-vis des paramètres de soudage de la géométrie de l'assemblage hétérogène acier/aluminium réalisé par le procédé MIG-CMT dans une configuration à clin est étudiée à travers un plan d'expérience. Les paramètres choisis comme facteurs d'influence sont la puissance de soudage, la distance entre la torche et la pièce ou "stick-out", le débit de gaz et la vitesse de soudage, tandis que les caractéristiques géométriques sélectionnées comme fonctions objectifs sont le poids de mét...

  5. Soudage hybride Laser-MAG d'un acier Hardox® Hybrid Laser Arc Welding of a Hardox® steel

    Chaussé Fabrice; Bertrand Emmanuel; Paillard Pascal; Dubourg Laurent; Lemaitre David; Carin Muriel

    2013-01-01

    Le soudage hybride laser-MAG est un procédé fortement compétitif par rapport aux procédés conventionnels notamment pour le soudage de fortes épaisseurs et les grandes longueurs de soudure. Il connait de ce fait un développement important dans l'industrie. La présente étude s'est portée sur la soudabilité de l'acier Hardox® par ce procédé. Un large panel de techniques de caractérisation a été employé (mesures thermiques, radiographie X, duretés Vickers, macrographie…). L'objectif étant de déte...

  6. Influence de la microstructure intragranulaire sur l'évolution des surfaces de charge d'un acier ferritique lors de trajets de déformation monotones et complexes

    FRANZ, Gérald; ABED-MERAIM, Farid; BEN ZINEB, Tarak; LEMOINE, Xavier; Berveiller, Marcel

    2007-01-01

    Deux modèles micromécaniques de comportement élastoplastique, développés en adoptant une formulation en transformations finies et couplés à une technique de transition d’échelle autocohérente, sont utilisés pour étudier l'évolution des surfaces de charge d'un acier ferritique polycristallin lors de changements de trajets de déformation. L'importance de l'impact de la microstructure intragranulaire sur l'anisotropie du comportement lors de trajets complexes est montrée par l'intégration de la ...

  7. Soudage hybride Laser-MAG d'un acier Hardox® Hybrid Laser Arc Welding of a Hardox® steel

    Chaussé Fabrice

    2013-11-01

    Full Text Available Le soudage hybride laser-MAG est un procédé fortement compétitif par rapport aux procédés conventionnels notamment pour le soudage de fortes épaisseurs et les grandes longueurs de soudure. Il connait de ce fait un développement important dans l'industrie. La présente étude s'est portée sur la soudabilité de l'acier Hardox® par ce procédé. Un large panel de techniques de caractérisation a été employé (mesures thermiques, radiographie X, duretés Vickers, macrographie…. L'objectif étant de déterminer l'influence des paramètres du procédé sur la qualité de la soudure et d'étendre notre compréhension des phénomènes se déroulant lors de ce type de soudage. Hybrid Laser Arc Welding (HLAW technology is a highly competitive metal joining process especially when high productivity is needed and for the welding of thick plates. It is a really new technology but its implementation in industry accelerates thanks to recent improvements of high power laser equipment and development of integrated hybrid welding heads. This study focuses on weldability of Hardox® 450 steel by HLAW. Welding tests were conducted by making critical process parameters vary. Then a large panel of characterization techniques (X-Ray radiography, macroscopic examination and hardness mapping was used to determine process parameters influence on weldability of Hardox 450® Steel.

  8. Étude expérimentale de l'interaction laser-matière dans le cas du soudage d'un acier inoxydable austénitique par laser Nd:YAG continu de 2 kW

    Dumord, E.; Jouvard, J.; Grevey, D.; Druetta, M.; Ottavi, P.

    1997-01-01

    L'interaction laser-matière se produisant lors du soudage par laser Nd:YAG continu de 2 kW d'un acier inoxydable austénitique est étudiée, et notamment les effets liés à la présence du capillaire dans le bain liquide, de façon à définir les paramètres utiles à la modélisation du processus. Le facteur d'absorption des cibles utilisées a été mesuré afin de mieux appréhender l'interaction laser Nd:YAG/acier inoxydable austénitique 304. Puis une approche expérimentale de détermination de l'angle ...

  9. Etude métallurgique du soudage par friction malaxage sur un acier à haute limite élastique destiné à la construction navale : le 80 HLES Metallurgical study of friction stir welding on a steel high yield for shipbuilding: The 80 HLES

    Allart Marion; Rückert Guillaume; Paillard Pascal

    2013-01-01

    Le soudage par friction malaxage est un procédé de soudage relativement récent (début des années 90). Il est aujourd'hui utilisé couramment sur des alliages légers mais ne l'est que depuis peu sur les aciers. L'objectif de nos travaux est de chercher à caractériser la microstructure métallurgique et l'état de déformation et de contrainte après soudage par friction malaxage sur des échantillons d'aciers à haute limite élastique utilisés dans l'industrie navale. Nous chercherons à comprendre le...

  10. Compréhension des mécanismes à l’origine de l’adhésion de Saccharomyces cerevisiae sur acier inoxydable: Implications pour l’hygiène des surfaces en industrie agroalimentaire

    Guillemot, Gaëlle

    2006-01-01

    Dans l’industrie agroalimentaire, l’adhésion de microorganismes contaminants sur les surfaces induit des effets néfastes à la fois en terme de qualité, d’hygiène et de santé publique. Dans cette étude, une forte adhésion de Saccharomyces cerevisiae sur l’acier inoxydable a été mise en évidence, à l’aide d’une chambre à écoulement cisaillé. La spécificité de ce matériau par rapport à d’autres surfaces « contrôle » a été démontrée pour des souches de levures d’origine variée. Cette spécificité ...

  11. Sur la modélisation du comportement thermomécanique et métallurgique des aciers. Application au procédé de soudage et de traitements thermiques

    Trinh, Ngoc Thuy

    2008-01-01

    Le travail de la thèse porte sur la modélisation fine des lois de comportement thermomécaniques et métallurgiques des aciers afin de déterminer l'état mécanique résiduel des structures lors d'une opération de soudage. Il s'agit de définir les cinétiques de transformation de phases à l'état solide ainsi que le comportement mécanique du matériau multiphasé. Dans un cadre théorique original-les matériaux standards généralisés avec des liaisons internes-nous avons proposé des modèles de comportem...

  12. Utilisation d'ondes de Love pour déterminer l'épaisseur d'une couche de cuivre déposée électrolytiquement sur un substrat d'acier

    Kiełczyński, P.; Pajewski, W.

    1986-01-01

    Cet article présente les résultats d'une expérience ayant pour objet de déterminer l'épaisseur d'une couche superficielle d'un matériau élastique à l'aide d'ondes de surface transversales et horizontales du type de Love. Les principes théoriques de la méthode appliquée ont été développés par les auteurs précédemment (NDT Int. 18, n° 1 (1985) 25-29). Les mesures ont été effectuées pour une couche de cuivre déposée par électrolyse sur un substrat d'acier. Plusieurs facteurs qui peuvent rendre l...

  13. Modélisation tridimensionelle de la fermeture induite par plasticité lors de la propagation d'une fissure de fatigue dans l'acier 304L

    Fiordalisi, Saverio,

    2014-01-01

    Ce travail de thèse s’inscrit dans le cadre des problèmes de fissuration par fatigue, détectéesnotamment dans des structures nucléaires et se situe dans la continuité de travaux déjà réalisésau laboratoire. L’objectif de cette étude est la réalisation d’un outil numérique de prédictiondu phénomène de fermeture induite par plasticité, au cours de la propagation d’une fissure defatigue dans une éprouvette CT, dans un acier inoxydable 304L, en prenant en comptel’influence simultanée de la forme ...

  14. Biodétérioration des structures portuaires en acier : synergie entre la physico-chimie du fer en milieu marin et les micro-organismes sulfurogènes

    Langumier, Mikaël

    2011-01-01

    Le but de ce travail était de mieux comprendre les mécanismes mis en jeu lors de la corrosion marine des structures en acier. Ces mécanismes impliquant l'influence de micro-organismes vivants, et notamment des bactéries sulfurogènes, l'étude a couplé des méthodes physico-chimiques à des techniques de microbiologie et de biologie moléculaire. Dans un premier temps, un système modèle de laboratoire a été élaboré afin d'étudier en détail les interactions entre les bactéries sulfato-réductrices (...

  15. Comportement des poteaux composites en profils creux en acier remplis de béton Behavior of composite columns in hollow steel section filled with concrete

    Othmani N.

    2012-09-01

    Full Text Available Le but de cet article, est la determination des rigidites flexionnelles EIx et EIy d’fune section mixte acier beton et plus precisement d’fun poteau en tube d’facier de section rectangulaire, remplie de beton, sollicitee a la flexion bi-axiale (N, Mx et My. L’festimation des rigidites sera faite a partir d’fune approche theorique par une analyse du poteau en elements finis (element barre a 4 degres de liberte, basee sur les conditions d’fequilibres a mi-portee en utilisant la relation moment-courbure (M–Φ de l’felement deforme par application de l’fequation suivante: EI=M/Φ. Le comportement des materiaux est celui comme adopte par les reglements Eurocode 2 et 3, respectivement pour le beton et l’facier. Afin de valider l’fapproche theorique utilisee dans cette etude, deux comparaisons ont ete faites : une premiere permettant de comparer les resultats des rigidites determinees par les relations moments courbures et celles calculees par l’fEurocode 4 et une deuxieme comparaison entre les charges de ruines de deux poteaux de grandeurs natures avec ceux testes au laboratoire [2]. Au vu des resultats obtenus, nous pouvons conclure que l’approche théorique utilisée dans cette étude ainsi que les modèles de comportement des matériaux sont adéquats pour ce genre de problèmes. The purpose of this paper is the determination of flexural stiffness EIx and EIy of a concrete filled rectangular cross section of a composite steel column, under biaxial bending (N, Mx and My. The rigidities will be estimated from a theoretical approach using a finite element analysis (element bar with 4 degrees of freedom, based on the equilibrium conditions at mid-span using the moment-curvature relationships (M–Φ of the deformed element by applying the following equation: EI=M/Φ. The material behavior is the one adopted by Eurocode 2 and 3, respectively, for concrete and steel. To validate the theoretical approach used, two comparisons

  16. Food irradiation

    Food irradiation is a promising technology in which food products are exposed to a controlled amount of radiant energy to eliminate disease-causing bacteria. The process can also control parasites and insects, reduce spoilage and inhibit ripening and sprouting. Food irradiation is endorsed by the most important health organisations (WHO, CDC, USDA, FDA, EFSA, etc.) and allowed in nearly 40 Countries. It is to remember that irradiation is not a substitute either for comprehensive food safety programs or for good food-handling practices. Irradiated foods must be labelled with either the statement treated with radiation or treated by irradiation and the international symbol for irradiation, the radura. Some consumer associations suppose negative aspects of irradiation, such as increase of the number of free radicals in food and decrease of antioxidant vitamins that neutralize them

  17. Irradiated planets

    We present models for the spectra emitted by irradiated planets and discuss the numerical methods used in the modeling. In addition, we show results of simple 3D calculations that are designed as a first step toward detailed multi-dimensional models of irradiated planets

  18. Food irradiation

    The paper discusses the need for effective and efficient technologies in improving the food handling system. It defines the basic premises for the development of food handling. The application of food irradiation technology is briefly discussed. The paper points out key considerations for the adoption of food irradiation technology in the ASEAN region (author)

  19. Food irradiation

    The author reviews in outline the present status of industrial gamma irradiation plants for food and medical sterilization and in particular lists commercial irradiation plants currently operating in the U.K., considering briefly plant design, efficiency, costs and dose control. (UK)

  20. Irradiation damage

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization

  1. Food irradiation

    Food irradiation can have a number of beneficial effects, including prevention of sprouting; control of insects, parasites, pathogenic and spoilage bacteria, moulds and yeasts; and sterilization, which enables commodities to be stored for long periods. It is most unlikely that all these potential applications will prove commercially acceptable; the extend to which such acceptance is eventually achieved will be determined by practical and economic considerations. A review of the available scientific literature indicates that food irradiation is a thoroughly tested food technology. Safety studies have so far shown no deleterious effects. Irradiation will help to ensure a safer and more plentiful food supply by extending shelf-life and by inactivating pests and pathogens. As long as requirement for good manufacturing practice are implemented, food irradiation is safe and effective. Possible risks of food irradiation are not basically different from those resulting from misuse of other processing methods, such as canning, freezing and pasteurization. (author)

  2. Irradiation damage

    Howe, L.M

    2000-07-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization.

  3. Etude métallurgique du soudage par friction malaxage sur un acier à haute limite élastique destiné à la construction navale : le 80 HLES Metallurgical study of friction stir welding on a steel high yield for shipbuilding: The 80 HLES

    Allart Marion

    2013-11-01

    Full Text Available Le soudage par friction malaxage est un procédé de soudage relativement récent (début des années 90. Il est aujourd'hui utilisé couramment sur des alliages légers mais ne l'est que depuis peu sur les aciers. L'objectif de nos travaux est de chercher à caractériser la microstructure métallurgique et l'état de déformation et de contrainte après soudage par friction malaxage sur des échantillons d'aciers à haute limite élastique utilisés dans l'industrie navale. Nous chercherons à comprendre les phénomènes métallurgiques qui interviennent en cours de soudage. The friction stir welding is a welding process relatively recent (early 90s. It is now commonly used on light alloys but is only recently on steels. The objective of our work is to try to characterize the metallurgical microstructure and state of stress and strain after friction stir welding on samples of high strength steels used in the shipbuilding industry. We seek to understand the metallurgical phenomena that occur during welding.

  4. Improvement of the SCC resistance of FCC alloys: influence of pre-fatigue on the SCC resistance of the austenitic stainless steel-316L in a MgCl{sub 2} boiling solution at 117 deg C; Recherche d'une amelioration du comportement en CSC d'alliages de structure CFC: influence d'une pre-deformation en fatigue oligocyclique sur le comportement en CSC de l'acier inoxydable austenitique 316L dans une solution bouillante de MgCl{sub 2} a 117 deg C

    Curiere, I. de

    2000-12-01

    The aim of this study is to analyse the effect of pre-fatigue of FCC materials on their mechanical and electrochemical response to better understand and delay the SCC damage. The material/environment couple tested is the 316L polycrystalline austenitic stainless steel in boiling MgCl{sub 2} at 30% mass. Samples are pre-strained in low cycle fatigue under plastic strain control, with a p/2 value of 0.4%, for various number of cycles (25%, 75% and at the number of cycles to reach saturation during pre-fatigue). It was found that only pre-fatigue at saturation improves the SCC resistance of the material, both on SSRT and constant load tests. A delayed crack initiation up to 10% of strain. which increases strain to failure by half. mostly accounts for this beneficial effect, during SSRT tests. Furthermore, other pre-straining only resulted in loss of strain to fracture and no delay in crack initiation. We related the crack initiation delay to the surface strain state due to pre-fatigue. It provides fine parallel slip bands. homogeneously located at the surface of the samples. This surface state induces an increasing anodic surface-cathodic surface ratio which lowers the kinetics of localised corrosion. thus that of crack initiation. We also show some experiments implying that pre-fatigue at saturation decreases the SCC crack growth velocity which can be understood through the CEP (Corrosion Enhanced Plasticity) Model. We also show that this beneficial effect is probably available on other fcc material/environment couples, such as OFHC Cu/ 1 M NaNO{sub 2} at pH 9. (author)

  5. Food irradiation

    Food treatment by means of ionizing energy, or irradiation, is an innovative method for its preservation. In order to treat important volumes of food, it is necessary to have industrial irradiation installations. The effect of radiations on food is analyzed in the present special work and a calculus scheme for an Irradiation Plant is proposed, discussing different aspects related to its project and design: ionizing radiation sources, adequate civil work, security and auxiliary systems to the installations, dosimetric methods and financing evaluation methods of the project. Finally, the conceptual design and calculus of an irradiation industrial plant of tubercles is made, based on the actual needs of a specific agricultural zone of our country. (Author)

  6. Fruits irradiation

    The objectives of this project in food irradiation are two-fold, to study the effect of irradiation in prolongation of useful storage life of fruits and to evaluate irradiation as a means of preserving fruits. However radiation is not intended to replace existing preservation processes but may be used in conjunction with current methods such as refrigeration, drying, fermentation etc. In fact radiation should combine with proper storage and packaging techniques in order to ensure maximum benefits. Ripening retardation of fruits by irradiation kinds of fruits: papaya, mango, rambutan, longan and durian. Changes in organoleptic properties of fruit flavor and taste, texture changes by taste panel estimation of significance level of results by statistical mathematical methods, chemical changes determination of climacteric peak in fruits by estimation of carbon dioxide evolution, vitamin C determination by Tillmann's method, carotenoid separation by thin layer chromatography, reducing sugars and acidity determination, volatile components of durian by gas-chromatography

  7. Food irradiation

    The preservation of food using irradiation may replace or be used in combination with traditional or conventional food preservation techniques. Studies have shown that the irradiation technique which uses less energy than other preservation methods is a potential way for reducing post harvest losses. However, economic feasibility among other constraints is the core factor to determine the success of the technique at commercial scale. The need and importance for considering this new technique in Malaysia are discussed here. (author)

  8. Food irradiation

    A worldwide standard on food irradiation was adopted in 1983 by codex Alimentarius Commission of the Joint Food Standard Programme of the Food and Agriculture Organization (FAO) of the United Nations and The World Health Organization (WHO). As a result, 41 countries have approved the use of irradiation for treating one or more food items and the number is increasing. Generally, irradiation is used to: food loses, food spoilage, disinfestation, safety and hygiene. The number of countries which use irradiation for processing food for commercial purposes has been increasing steadily from 19 in 1987 to 33 today. In the frames of the national programme on the application of irradiation for food preservation and hygienization an experimental plant for electron beam processing has been established in Inst. of Nuclear Chemistry and Technology. The plant is equipped with a small research accelerator Pilot (19 MeV, 1 kW) and industrial unit Electronika (10 MeV, 10 kW). On the basis of the research there were performed at different scientific institutions in Poland, health authorities have issued permissions for irradiation for; spices, garlic, onions, mushrooms, potatoes, dry mushrooms and vegetables. (author)

  9. Etude des effets du martelage repetitif sur les contraintes residuelles

    Hacini, Lyes

    L'assemblage par soudage peut engendrer des contraintes residuelles. Ces contraintes provoquent des fissurations prematurees et un raccourcissement de la duree de vie des composants. Dans ce contexte, le martelage robotise est utilise pour relaxer ces contraintes residuelles. Trois volets sont presentes: le premier est l'evaluation des effets des impacts unitaires repetes sur le champ de contraintes developpe dans des plaques d'acier inoxydable austenitique 304L vierges ou contenant des contraintes residuelles initiales. Dans la deuxieme partie de ce projet, le martelage est applique grace au robot SCOMPI. Les contraintes residuelles induites et relaxees par martelage sont ensuite mesurees par la methode des contours, qui a ete adaptee a cet effet. Dans la troisieme partie, le martelage est modelise par la methode des elements finis. Un modele axisymetrique developpe grace au logiciel ANSYS permet de simuler des impacts repetes d'un marteau elastique sur une plaque ayant un comportement elastoplastique.

  10. The compatibility of chromium-aluminium steels with high pressure carbon dioxid at intermediate- temperatures; Compatibilite des aciers au chrome-aluminium avec le gaz carbonique sous pression aux temperatures moyennes

    Leclercq, D.; Loriers, H.; David, R.; Darras, E. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    With a view to their use in the exchangers of nuclear reactors of the graphite-gas or heavy water-gas types, the behaviour of chromium-aluminium steels containing up to 7 per cent chromium and 1.5 per cent aluminium has been studied in the presence of high-pressure carbon dioxide at temperatures of between 400 and 700 deg. C. The two most interesting grades of steel (2 per cent Cr - 0.35 per cent Al - 0.35 per cent Mo and 7 per cent Cr - 1.5 per cent Al - 0.6 per cent Si) are still compatible with carbon dioxide up to 550 and 600 deg. C respectively. A hot dip aluminised coating considerably increases resistance to oxidation of the first grade and should make possible its use up to temperatures of at least 600 deg. C. (authors) [French] Dans l'optique de leur emploi dans les echangeurs de reacteurs nucleaires des filieres graphite-gaz ou eau lourde-gaz, le comportement en presence de gaz carbonique sous pression d'aciers au chrome-aluminium, contenant jusqu'a 7 pour cent de chrome et 1,5 pour cent d'aluminium a ete etudie entre 400 et 700 deg. C. Les deux nuances les plus interessantes (2 pour cent Cr - 0,35 pour cent Al - 0,35 pour cent Mo et 7 pour cent Cr - 1,5 pour cent Al - 0,6 pour cent Si) restent compatibles avec le gaz carbonique jusqu'a 550 et 600 deg. C respectivement. Un revetement d'aluminium, effectue par immersion dans un bain fondu, ameliore notablement la resistance a l'oxydation de la premiere et doit permettre son empioi jusqu'a 600 deg. C au moins. (auteurs)

  11. Commercial irradiator

    Commercial irradiation, the treatment of products with gamma radiation principally using a Cobalt-60 source, had its beginnings in Europe and Australia 25 years ago. To date the most successful application of the process is the sterilization of medical products and, for a variety of reasons, gamma sterilization is now becoming dominant in this important field. Many other applications have been evaluated over the years and the most exciting is undoubtedly food irradiation for which there is a vast potential. The commercial feasibility of setting up and irradiation facility is a complex subject and the selection of Cobalt-60 gamma plant depends on a number of technical and economic considerations. The parameters which determine the design and capacity of the optimum plant include throughput, product size and dose requirements; a balance has to be struck between plant flexibility and overall economy. The Ansell irradiators are designed primarily for the sterilization of medical products although some experimental food irradiation has been done, particularly in Australia. (author)

  12. Vinca irradiator

    The development programme of the VINCA radiosterilisation centre involves plans for an irradiator capable of working in several ways. Discontinuous operation. The irradiator is loaded for a certain period then runs automatically until the moment of unloading. This method is suitable as long as the treatment capacity is relatively small. Continuous operation with permanent batch loading and unloading carried out either manually or automatically (by means of equipment to be installed later). Otherwise the design of the apparatus is highly conventional. The source is a vertical panel submersible in a pool. The conveyor is of the 'bucket' type, with 4 tiers to each bucket. The batches pass successively through all possible irradiation positions. Transfert into and out of the cell take place through a maze, which also provides access to the cell when the sources are in storage at the bottom of the pool

  13. Food irradiation

    The colloquium has been held on the occasion of the commissioning of a new linear electron accelerator. The 17 papers presented by the experts give a survey of the present status of food irradiation and related aspects. Every paper has been analysed and prepared for retrieval from the database. (orig.)

  14. Food irradiation: An update

    Recent regulatory and commercial activity regarding food irradiation is highlighted. The effects of irradiation, used to kill insects and microorganisms which cause food spoilage, are discussed. Special attention is given to the current regulatory status of food irradiation in the USA; proposed FDA regulation regarding the use of irradiation; pending irradiation legislation in the US Congress; and industrial applications of irradiation

  15. Modélisation numérique d'un procédé de soudage hybride arc / laser en approche level set : application au soudage multi-passes de tôles d'acier de forte épaisseur

    Desmaison, Olivier

    2013-01-01

    Le soudage hybride arc / laser représente une solution adéquate à l'assemblage de tôles d'acier de forte épaisseur. La présence d'une source laser en amont de la torche MIG permet d'accroître la productivité du procédé tout en assurant une excellente qualité de la soudure. Cependant la phénoménologie complexe de ce procédé multiphysique n'est pas encore totalement maîtrisée, ce qui motive le développement d'outils de simulation numérique. La présente étude s'est déroulée dans le cadre d'un pr...

  16. Food irradiation

    Various aspects of food treatment by cobalt 60 or caesium 137 gamma radiation are reviewed. One of the main applications of irradiation on foodstuffs lies in its ability to kill micro-organisms, lethal doses being all the lower as the organism concerned is more complex. The effect on parasites is also spectacular. Doses of 200 to 300 krad are recommended to destroy all parasites with no survival period and no resistance phenomenon has ever been observed. The action of gamma radiation on macromolecules was also investigated, the bactericide treatment giving rise to side effects by transformation of food components. Three examples were studied: starch, nucleic acids and a whole food, the egg. The organoleptic aspect of irradiation was examined for different treated foods, then the physical transformations of unpasteurized, heat-pasteurized and radio-pasteurized eggs were compared. The report ends with a brief analysis of the toxicity and conditions of application of the treatment

  17. Food irradiation

    Radiation processing of food is based on irradiation by gamma radiation from a 60Co source or X-ray with energy < 5 MeV or electron beam with energy < 10 MeV. This technique is now completely mastered. About 30 countries use this technique to extend the storage life of food but the total quantity processed is weak, only 30000 tons a year for France. Some countries like Morocco or Tunisia have launched technical programmes about the radiation processing of dates and vegetable oil. These programmes may lead to the creation of a quality label. A joint laboratory between CEA and the Aix-Marseille-3 university is working on the detection of food irradiation in order to fight the fraud. 3 techniques are being investigated: thermoluminescence, electronic paramagnetism resonance and a chemical method. (A.C.)

  18. Endolymphatic irradiation

    The authors analysed the clinical evolution and the result of renal transplantation some years after irradiation in 24 patients (group I) who received endolymphatic 131I as a pre-transplantation immunesuppresive measure. The control group (group II) consisted of 24 non-irradiated patients comparable to group I in age, sex, primary disease, type of donor and immunesuppressive therapy. Significant differences were observed between the two groups regarding such factors a incidence and reversibility of rejection crises in the first 60 post-transplantation days, loss of kidney due to rejection, and dosage of azathioprine. The authors conclude that this method, besides being harmless, has prolonged immunesuppressive action, its administration being advised for receptores of cadaver kidneys, mainly those who show positive cross-match against HLA antigens for painel. (Author)

  19. Food irradiation

    The first part of this data is relative to the study of chemical modifications induced by gamma radiations (60Co, 137Cs) on macromolecules of food and their contaminates with the help of two examples: starch and nucleic acids. Then the second part shows what are the consequences of irradiation on food and their preservation; we make distinction between useful effects (for instance germination inhibition of tubercules, destruction of insects or micro-organisms) and the results which are contingently bad for nutritional, technological and above all toxicologic aspects. The last part is relative to a short restatement of the problems inherent in the industrialization of this treatment

  20. Microstructure and embrittlement of VVER 440 reactor pressure vessel steels; Microstructure et fragilisation des aciers de cuve des reacteurs nucleaires VVER 440

    Hennion, A

    1999-03-15

    27 VVER 440 pressurised water reactors operate in former Soviet Union and in Eastern Europe. The pressure vessel, is made of Cr-Mo-V steel. It contains a circumferential arc weld in front of the nuclear core. This weld undergoes a high neutron flux and contains large amounts of copper and phosphorus, elements well known for their embrittlement potency under irradiation. The embrittlement kinetic of the steel is accelerated, reducing the lifetime of the reactor. In order to get informations on the microstructure and mechanical properties of these steels, base metals, HAZ, and weld metals have been characterized. The high amount of phosphorus in weld metals promotes the reverse temper embrittlement that occurs during post-weld heat treatment. The radiation damage structure has been identified by small angle neutron scattering, atomic probe, and transmission electron microscopy. Nanometer-sized clusters of solute atoms, rich in copper with almost the same characteristics as in western pressure vessels steels, and an evolution of the size distribution of vanadium carbides, which are present on dislocation structure, are observed. These defects disappear during post-irradiation tempering. As in western steels, the embrittlement is due to both hardening and reduction of interphase cohesion. The radiation damage specificity of VVER steels arises from their high amount of phosphorus and from their significant density of fine vanadium carbides. (author)

  1. Is food irradiation harmful

    The paper reports on a seminar on 'The irradiation of food', held in London, 1987, and organised by the Royal Society and the Association of British Science Writers. A description is given of the food irradiation techniques. Problems with food irradiation are discussed with respect to the nutritional value of food, killing of microorganisms, survival of fungi following treatment, mutation of irradiated bacteria, and chemical changes produced in the food. Monitoring and controls of food that has been irradiated is discussed. A personal opinion of irradiated food by the author is given, including a verdict on irradiated food. (UK)

  2. Prévision de l'épaisseur du film passif d'un acier inoxydable 316L soumis au fretting corrosion grâce au Point Defect Model, PDM Predicting the steady state thickness of passive films with the Point Defect Model in fretting corrosion experiments

    Geringer Jean

    2013-11-01

    Full Text Available Les implants orthopédiques de hanche ont une durée de vie d'environ 15 ans. Par exemple, la tige fémorale d'un tel implant peut être réalisée en acier inoxydable 316L ou 316LN. Le fretting corrosion, frottement sous petits déplacements, peut se produire pendant la marche humaine en raison des chargements répétés entre le métal de la prothèse et l'os. Plusieurs investigations expérimentales du fretting corrosion ont été entreprises. Cette couche passive de quelques nanomètres, à température ambiante, est le point clef sur lequel repose le développement de notre civilisation, selon certains auteurs. Ce travail vise à prédire les épaisseurs de cette couche passive de l'acier inoxydable soumis au fretting corrosion, avec une attention spécifique sur le rôle des protéines. Le modèle utilisé est basé sur le Point Defect Model, PDM (à une échelle microscopique et une amélioration de ce modèle en prenant en compte le processus de frottement sous petits débattements. L'algorithme génétique a été utilisé pour optimiser la convergence du problème. Les résultats les plus importants sont, comme démontré avec les essais expérimentaux, que l'albumine, la protéine étudiée, empêche les dégradations de l'acier inoxydable aux plus faibles concentrations d'ions chlorure ; ensuite, aux plus fortes concentrations de chlorures, un temps d'incubation est nécessaire pour détruire le film passif. Some implants have approximately a lifetime of 15 years. The femoral stem, for example, should be made of 316L/316LN stainless steel. Fretting corrosion, friction under small displacements, should occur during human gait, due to repeated loadings and un-loadings, between stainless steel and bone for instance. Some experimental investigations of fretting corrosion have been practiced. As well known, metallic alloys and especially stainless steels are covered with a passive film that prevents from the corrosion and degradation

  3. Detection of irradiated liquor

    D-2,3-butanediol is formed by irradiation processes in irradiated liquors. This radiolytic product is not formed in unirradiated liquors and its presence can therefore be used to identify whether a liquor has been irradiated or not. The relation meso/dl∼1 for 2,3-butanediol and the amount present in irradiated liquors may therefore be used as an indication of the dose used in the irradiation. (author)

  4. Étude expérimentale de l'interaction laser-matière dans le cas du soudage d'un acier inoxydable austénitique par laser Nd:YAG continu de 2 kW

    Dumord, E.; Jouvard, J. M.; Grevey, D.; Druetta, M.; Ottavi, P.

    1997-05-01

    The laser-matter interaction acting during cw 2 kW Nd:YAG laser welding of an austenitic stainless steel is studied and particulary the effects linked to the presence of a keyhole in the liquid bath. This is done in order to define parameters useful to the process modelling. The absorption factor of target has been measured in order to better understand the Nd:YAG laser/stainless steel 304 interaction. Then an experimental approach of the keyhole angle value determination is proposed. Values are presented showing the important keyhole angle at the bottom of the bead. Finally a study relative to the plume above the keyhole shows that it is responsible for the formation of the nail-head part, observed on the experimental melting zone, by laser beam scattering. L'interaction laser-matière se produisant lors du soudage par laser Nd:YAG continu de 2kW d'un acier inoxydable austénitique est étudiée, et notamment les effets liés à la présence du capillaire dans le bain liquide, de façon à définir les paramètres utiles à la modélisation du processus. Le facteur d'absorption des cibles utilisées a été mesuré afin de mieux appréhender l'interaction laser Nd:YAG/acier inoxydable austénitique 304. Puis une approche expérimentale de détermination de l'angle d'inclinaison du capillaire est proposée. Des valeurs sont présentées montrant la forte inclinaison du capillaire en fond de cordon. Finalement une étude relative au panache présent audessus du capillaire met en évidence qu'il est responsable de la formation de la partie en tête de clou observée sur les zones fondues expérimentales par diffusion du faisceau laser

  5. Irradiation of goods

    The necessary dose and the dosage limits to be observed depend on the kind of product and the purpose of irradiation. Product density and density distribution, product dimensions, but also packaging, transport and storage conditions are specific parameters influencing the conditions of irradiation. The kind of irradiation plant - electron accelerator or gamma plant - , its capacity, transport system and geometric arrangement of the radiation field are factors influencing the irradiation conditions as well. This is exemplified by the irradiation of 3 different products, onions, deep-frozen chicken and high-protein feed. Feasibilities and limits of the irradiation technology are demonstrated. (orig.)

  6. Food irradiation in China

    In this paper, the author discussed the recent situation of food irradiation in China, its history, facilities, clearance, commercialization, and with emphasis on market testing and public acceptance of irradiated food. (author)

  7. Economics of food irradiation

    Economic aspects of food irradiation and direct economic benefits accruing from the application of food irradiation are discussed. A formula is presented to estimate the net economic benefit due to radiation processing of food. (M.G.B .)

  8. JMTR irradiation handbook

    A wide variety of nuclear irradiation and post-irradiation experiments are available using the JMTR (Japan Materials Testing Reactor, 50 MW) and the multi-cell hot laboratory associated with the JMTR. In this Handbook, an application manual for conducting irradiation and post-irradiation experiments using those facilities is provided. The Handbook is primarily designed to aid the experimenter and to serve as a reference for communications between the experimenter and the Division of JMTR Project. (author)

  9. JMTR irradiation handbook

    A wide variety of nuclear irradiation and post-irradiation experiments are available using the Japan Materials Testing Reactor, 50 MW (JMTR) and the multi-cell hot laboratory associated with the JMTR. In this Handbook, an application manual for conducting irradiation and post-irradiation experiments using those facilities is provided. The Handbook is primarily designed to aid the experimenter and to serve as a reference for communications between the experimenter and the Department of JMTR Project. (author)

  10. Containers in food irradiation

    The preservation of food by irradiation is promising technology which increases industrial application. Packaging of irradiated foods is an integral part of the process. Judicious selection of the package material for successful trade is essential. In this paper is presented a brief review of important aspects of packaging in food irradiation

  11. Canadian Food Irradiation Facilities

    Atomic Energy of Canada Limited (AECL) began work on the irradiation of potatoes in 1956, using spent fuel rods as the radiation source. In 1958 the first Gammacell 220, a self-contained irradiator, was designed and manufactured by AECL, and cobalt-60 was then used exclusively in the food irradiation programme. In 1960 the first food and drug clearance was obtained for potatoes. The next stage was to demonstrate to the potato industry that cobalt-60 was a safe, simple and reliable tool, and that irradiation would inhibit sprouting under field conditions. A mobile irradiator was designed and produced by AECL in 1961 to carry out this pilot-plant programme. The irradiator was mounted on a fully-equipped road trailer and spent the 1961/1962 season irradiating one million pounds of potatoes at various points in Eastern Canada. In 1965 the first commercial food irradiator was designed and built by AECL for Newfield Products, Ltd. Whilst the potato programme was under way, AECL initiated co-operative programmes with Canadian food research laboratories, using additional Gammacells. In 1960, AECL constructed an irradiation facility in a shielded room at its own plant in Ottawa for the irradiation of larger objects, such as sides of pork and stems of bananas. During 1963 the mobile irradiator, already a most useful tool, was made more versatile when its source strength was increased and it was equipped with a product cooling system and van air conditioning. Following these modifications, the unit was employed in California for the irradiation of a wide spectrum of fruits at the United States Department of Agriculture Station in Fresno. The Gammacell, mobile irradiator, shielded-room facility, the commercial food irradiator and some of the main food programmes are described in detail. There is an increasing amount of interest in irradiation by the food industry, and prospects are encouraging for future installations. (author)

  12. Welding irradiated stainless steel

    Conventional welding processes produced severe underbead cracking in irradiated stainless steel containing 1 to 33 appm helium from n,a reactions. A shallow penetration overlay technique was successfully demonstrated for welding irradiated stainless steel. The technique was applied to irradiated 304 stainless steel that contained 10 appm helium. Surface cracking, present in conventional welds made on the same steel at the same and lower helium concentrations, was eliminated. Underbead cracking was minimal compared to conventional welding methods. However, cracking in the irradiated material was greater than in tritium charged and aged material at the same helium concentrations. The overlay technique provides a potential method for repair or modification of irradiated reactor materials

  13. Irradiation effects on polycaprolactone

    The structure and some physical properties of γ-irradiated polycaprolactone (PCL), a semi-crystalline linear saturated polyester, were studied as function of the irradiation dose level. The critical dose level for gel formation is 26 Mrad and above this irradiation dose the number of scission events is similar to the number of crosslinking events. G.p.c. results show that the initial rather narrow molecular weight distribution gradually widens with increasing dose in the pre-gelation region. A significant difference between first and second d.s.c. scans of irradiated PCL is shown and explained. Scission and crosslinking reactions associated with the irradiation process occur preferentially in the non-ordered regions. Small irradiation doses, 2 to 5 Mrad, are shown to have a dramatic effect on the tensile elongation at break by converting ductile PCL samples into brittle materials. (author)

  14. Endommagement des aciers TWIP pour application automobile

    Lorthios, Julie

    2011-01-01

    Co-encadrement de la thèse : Matthieu Mazière Ultra high strength Fe-Mn-C Twinning Induced Plasticity (TWIP) austenitic steels exhibit excellent formability for automotive safety parts. By refining the microstructure during straining, deformation twinning induces a high hardening rate and provides high ultimate tensile strength (>1000MPa) combined with excellent ductility (>50%). However, plastic instabilities and TWIP effect lead to atypical failures modes and standard forming limit curve...

  15. Numerical simulation of a Charpy test and correlation of fracture toughness with fracture energy. Vessel steel and duplex stainless steel of the primary loop; Simulation numerique d`un essai de resilience et correlation entre resilience et proprites de tenacite. Acier de cuve et acier austenoferritique du circuit primaire

    Breban, P; Eripret, C. [Departement MTC, Service RNE, Direction des Etudes et Recherches, Electricite de France (EDF), 92 - Clamart (France)

    1995-12-31

    The analysis methods used to evaluate the harmlessness of defects in the components of the primary coolant circuit of pressurized water reactor are based on the knowledge of the failure properties of concerned materials. The toughness is used to be measured through tests performed on normalized samples. But in some cases, especially for the vessel steel submitted to irradiation effects or for cast components in duplex stainless steel sensitive to thermal ageing, these measurements are not available on the material aged in operation. Therefore, fracture resistance has been evaluated through Charpy tests. Toughness is thus obtained on the basis of an empirical correlation. To improve these predictions, a modeling of the Charpy test in the framework of the local approach to fracture has been performed, for both materials. For the vessel steel, a complete evaluation of toughness has been achieved on the basis of a bidimensional viscoplastic modeling under large strain assumptions and a post-treatment with a Weibull model (cleavage fracture). The main hypothesis (partition between plain stress and plain strain areas in the bidimensional modeling) was corrected after a three dimensional calculations with the finite element program Code-Aster. The fracture analysis put into evidence that damage considerations like cavity nucleation and growth have to be introduced in the model in order to improve the description of physical phenomena. Two ways of progress have been suggested and are in course of being investigated, one in the framework of local approach to failure, the other with the help of micro-macro relationship. With regard to the duplex steel, the description of a Charpy (U) test allowed to clearly discriminate between crack initiation and propagation phases. A modeling through an equivalent homogenous material with a damage law based on a modified Gurson potential enables to describe quantitatively both phases of fracture. It clearly appears that a reliable

  16. Identification of irradiated chicken

    Frozen chicken and chicken parts were irradiated at a dose of 5 kGy with Co-60. The irradiated chicken and chicken parts were identified by determination of three radiation-induced hydrocarbons from the lipid fraction. Isolation was carried out by high-vacuum distillation with a cold-finger apparatus. The detection of the hydrocarbons was possible in all irradiated samples by gaschromatography/mass spectrometry. (orig.)

  17. Gamma irradiation devices

    The main parameters and the preparation procedures of the gamma radiation sources frequently applied for irradiation purposes are discussed. In addition to 60Co and 137Cs sources also the nuclear power plants offer further opportunities: spent fuel elements and products of certain (n,γ) reactions can serve as irradiation sources. Laboratory scale equipments, pilot plant facilities for batch or continuous operation, continuous industrial irradiators and special multipurpose, mobile and panorama type facilities are reviewed including those in Canada, USA, India, the Soviet Union, Hungary, UK, Japan and Australia. For irradiator design the source geometry dependence of the spatial distribution of dose rates can be calculated. (V.N.)

  18. Irradiation of food

    A committee has on instructions from the swedish government made an inquiry into the possible effects on health and working environment from irradition of food. In this report, a review is presented on the known positiv and negative effects of food irradiation Costs, availabilty, shelf life and quality of irradiated food are also discussed. According to the report, the production of radiolysis products during irradiation is not easily evaluated. The health risks from irradiation of spices are estimated to be lower than the risks associated with the ethenoxid treatment presently used. (L.E.)

  19. Food irradiation. An alternative

    In order to start a food irradiation program, one needs to perform some tests, such as: local handling problems, consumer acceptance and government licenses. At this point the cost of a special food irradiator can be considered a too high investment. It is proposed that for the irradiation of a few tons of several food items, a commercial irradiator for medical products sterilization be employed. With the use of an ''experimental loop'' and some special positions inside the irradiation chamber, it is possible to irradiate even potatoes and onions, at doses ranging from 100 Gy to 200 Gy. The quantities, depending on the source activity, can be around 300 kg per hour. For doses near 10 kGy, the normal procedure used for sterilization of medical products can be employed, while changing the cycle on the machine. In the case of an experimental loop within a JS-7400 (AECC) irradiator at a dose rate of 20 Gy per minute, around 200 kg of potatoes per hour can be irradiated. The experimental positions inside the chamber have a dose rate of 60 Gy per hour, and the batch capacity is 250 kg, so that 250 kg can be irradiated each 1,5 hour

  20. Facts about food irradiation: Chemical changes in irradiated foods

    This fact sheet addresses the safety of irradiated food. The irradiation process produces very little chemical change in food, and laboratory experiments have shown no harmful effects in animals fed with irradiated milk powder. 3 refs

  1. Mobile irradiation robot - computer modelling of the irradiation process

    For irradiation of cultural objects, which are damaged by wood-destroying insects or fungi, with the automatized irradiation robot, the computer code MOBROB1 for irradiation planning was developed and is presented. (author)

  2. Irradiation damage in superconductors

    Most superconductors are quite sensitive to irradiation defects. Critical temperatures may be depressed, critical currents may be increased, by irradiation, but other behaviours may be encountered. In compounds, the sublattice in which defects are created is of significant importance. 24 refs

  3. Materials modified by irradiation

    Application of radiation in pharmaceutical sciences and cosmetology, polymer materials, food industry, environment, health camre products and packing production is described. Nanotechnology is described more detailed, because it is less known as irradiation using technology. Economic influence of the irradiation on the materials value addition is shown

  4. Materials modified by irradiation

    Application of radiation in pharmaceutical sciences and cosmetology, polymer materials, food industry, environment, health camre products and packing production is described. Nano-technology is described more detailed, because it is less known as irradiation using technology. Economic influence of the irradiation on the materials value addition is shown

  5. Food irradiation control

    A brief review is given of the control and monitoring of food irradiation with particular emphasis on the UK situation. After describing legal aspects, various applications of food irradiation in different countries are listed. Other topics discussed include code of practice for general control for both gamma radiation and electron beam facilities, dose specification, depth dose distribution and dosimetry. (U.K.)

  6. Food Irradiation in Japan

    Since 1967 research activities on food irradiation in Japan have been carried out under the National Food Irradiation Programme by the Japanese Atomic Energy Commission. The programme has been concentrated on the technological and economical feasibility and wholesomeness testings of seven irradiated food items of economic importance to the country, i.e. potatoes, onions, wheat, rice, “kamaboko” (fish-paste products), “Vienna” sausages and mandarin oranges. By now most studies, including wholesomeness testings of these irradiated food items, have been completed. In Japan, all foods or food additives for sale are regulated by the Food Sanitation Law enforced in 1947. Based on studies made by the national programme, irradiated potatoes were given “unconditional acceptance” for human consumption in 1972. At present, irradiated potatoes are the only food item which has so far been approved by the Minister of Health and Welfare. Unless the Minister of Health and Welfare has declared that items are not harmful to human health on obtaining comments from the Food Sanitation Investigation Council, no irradiated food can be processed or sold. In addition, the import of irradiated foodstuffs other than potatoes from foreign countries is prohibited by law.

  7. Phase stability under irradiation

    Experimental evidences of radiation induced instability are described then it is shown what theoretical approaches are relevant. Radiation induced segregation and precipitation in alloys irradiated at constant chemical composition, precipitate re-solution, order-disorder transition under irradiation and amorphization are examined

  8. Irradiation Creep in Graphite

    Ubic, Rick; Butt, Darryl; Windes, William

    2014-03-13

    An understanding of the underlying mechanisms of irradiation creep in graphite material is required to correctly interpret experimental data, explain micromechanical modeling results, and predict whole-core behavior. This project will focus on experimental microscopic data to demonstrate the mechanism of irradiation creep. High-resolution transmission electron microscopy should be able to image both the dislocations in graphite and the irradiation-induced interstitial clusters that pin those dislocations. The team will first prepare and characterize nanoscale samples of virgin nuclear graphite in a transmission electron microscope. Additional samples will be irradiated to varying degrees at the Advanced Test Reactor (ATR) facility and similarly characterized. Researchers will record microstructures and crystal defects and suggest a mechanism for irradiation creep based on the results. In addition, the purchase of a tensile holder for a transmission electron microscope will allow, for the first time, in situ observation of creep behavior on the microstructure and crystallographic defects.

  9. Issues in food irradiation

    This discussion paper has two goals: first, to raise public awareness of food irradiation, an emerging technology in which Canada has the potential to build a new industry, mainly oriented to promising overseas markets; and second, to help build consensus among government and private sector decision makers about what has to be done to realize the domestic and export potential. The following pages discuss the potential of food irradiation; indicate how food is irradiated; outline the uses of food irradiation; examine questions of the safety of the equipment and both the safety and nutritional value of irradiated food; look at international commercial developments; assess the current and emerging domestic scene; and finally, draw some conclusions and offer suggestions for action

  10. Irradiation of goods

    Mechanical handling apparatus is adapted to handle goods, such as boxed fruit, during a process of irradiation, in palletized form. Palletized goods are loaded onto wheeled vehicles in a loading zone. Four vehicles are wheeled on a track into an irradiation zone via a door in a concrete shield. The vehicles are arranged in orthogonal relationship around a source of square section. Turntables are positioned at corners of the square shaped rail truck around the source selectively to turn the vehicles to align then with track sections. Mechanical manipulating devices are positioned in the track sections opposed to sides of the source. During irradiation, the vehicles and their palletized goods are cylically moved toward the source to offer first sides of the goods for irradiation and are retraced from the source and are pivoted through 900 to persent succeeding sides of the goods for irradiation

  11. Contribution à la modélisation du soudage TIG des tôles minces d'acier austénitique 304L par un modèle source bi-elliptique, avec confrontation expérimentale

    Aissani, M.; Maza, H.; Belkessa, B.; Maamache, B.

    2005-05-01

    Ce travail contribue dans la modélisation du phénomène du soudage de l'acier inoxydable Austénitique 304L, afin d'étudier le comportement thermique d'un joint de soudure, obtenu par le procédé de soudage à l'arc électrique TIG (Tungsten-Inert-Gas). Le modèle simulant la source d'énergie de soudage, utilise une distribution surfacique Gaussienne du flux de chaleur provenant de l'arc électrique. La forme de cette source est supposée circulaire pour un premier cas et de forme bi-elliptique pour un second cas, tout en procédant à l'évaluation des champs et cycles thermiques à chaque instant, pour déterminer l'étendu des zones à risque, et l'effet de la vitesse de soudage sur ces dernières. Permettant ainsi de remonter par la suite, aux problèmes de contraintes résiduelles et déformations générées dans l'assemblage soudé. L'équation de chaleur régissant le problème est discrétisée par la méthode des volumes finis. Les calculs sont effectués en considérant que les propriétés physiques et thermiques ainsi que les conditions aux limites de convection et rayonnement, sont dépendante de la température. Pour évaluer la précision du modèle, une comparaison avec des mesures expérimentales de température d'un essai de soudage a été effectuée, les résultats indiquent un bon accord.

  12. Modélisation du procédé de soudage hybride Arc / Laser par une approche level set application aux toles d'aciers de fortes épaisseurs A level-set approach for the modelling of hybrid arc/laser welding process application for high thickness steel sheets joining

    Desmaison Olivier

    2013-11-01

    Full Text Available Le procédé de soudage hybride Arc/Laser est une solution aux assemblages difficiles de tôles de fortes épaisseurs. Ce procédé innovant associe deux sources de chaleur : un arc électrique produit par une torche MIG et une source laser placée en amont. Ce couplage améliore le rendement du procédé, la qualité du cordon et les déformations finales. La modélisation de ce procédé par une approche Level Set permet une prédiction du développement du cordon et du champ de température associé. La simulation du soudage multi-passes d'une nuance d'acier 18MnNiMo5 est présentée ici et les résultats sont comparés aux observations expérimentales. The hybrid arc/laser welding process has been developed in order to overcome the difficulties encountered for joining high thickness steel sheets. This innovative process gathers two heat sources: an arc source developed by a MIG torch and a pre-located laser source. This coupling improves the efficiency of the process, the weld bead quality and the final deformations. The Level-Set approach for the modelling of this process enables the prediction of the weld bead development and the temperature field evolution. The simulation of the multi-passes welding of a 18MnNiMo5 steel grade is detailed and the results are compared to the experimental observations.

  13. Volatility of ruthenium during vitrification operations on fission products. part 1. nitric solutions distillation concentrates calcination. part 2. fixation on a steel tube. decomposition of the peroxide; Volatilite du ruthenium au cours des operations de vitrification des produits de fission. 1. partie distillation des solutions nitriques calcination des concentrats 2. partie fixation sur un tube d'acier decomposition du peroxyde

    Ortins de Bettencourt, A.; Jouan, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-07-01

    fission, un gros pourcentage de ruthenium initialement present dans ces solutions sous forme de nitrates de nitrosylruthenium est volatilise en donnant du peroxyde qui se decompose lui-meme en bioxyde de ruthenium. Ce travail a pour but l'etude de la volatilite du ruthenium au cours des procedes de vitrification : Durant la distillation des solutions nitriques, nous avons etudie en particulier l'influence sur la volatilite de la temperature, de la forme chimique du ruthenium introduit, du barbotage d'un gaz a travers la solution, de la concentration nitrique et de la concentration en nitrates. Durant la calcination, nous avons observe l'influence de la temperature, du temps, du debit et de la nature du gaz d'entrainement ainsi que l'action du bioxyde de ruthenium et de l'oxyde de fer sur la volatilite du ruthenium. Partie 2. Ce rapport concerne l'etude de la decomposition thermique du peroxyde de ruthenium, RuO{sub 4}, et de son depot sur les conduites en acier. Apres un rappel bibliographique des diverses proprietes de ce corps, nous etudions, dans une premiere partie, son depot sur un tube d'acier. Pour cela nous faisons passer un courant gazeux contenant du RuO{sub 4} marque au {sup 106}Ru dans un tube en acier inoxydable soumis a un gradient de temperature decroissant dans le sens du debit gazeux. Nous determinons la temperature a laquelle RuO{sub 4} se depose ou se fixe sur le tube et nous etudions l'influence de la vitesse des gaz sur ce depot. Dans une deuxieme partie nous essayons d'etudier par une methode statique la cinetique de la reaction de decomposition du peroxyde de ruthenium en son bioxyde: RuO{sub 4} {yields} RuO{sub 2} + O{sub 2}. Nous essayons pour cela d'introduire RuO{sub 4} gazeux dans un recipient place dans un four electrique et tentons de suivre l'evolution de la reaction par comptage {gamma}. (auteur)

  14. Onion irradiation - a case study

    Onion irradiation prevents sprouting associated with long term storage. Under the climatic conditions of Central Europe, only that part of onions should be irradiated which is needed to supply the domestic market during the months of May to July. Two types of irradiation plants, a bulk-irradiation and a multipurpose large-scale irradiation plant are used for onion irradiation. Technical data, throughput, cost-related parameters of onion irradiation are discussed. Onion irradiation for long term storage is beneficial to the national economy as well as to the business management. (author) 13 refs.; 11 tabs

  15. Irradiation of fusion materials

    In collaboration with the EFDA (European Fusion Development Agreement), SCK-CEN irradiates several materials in the BR2 reactor at different temperatures and up to different doses to study their mechanical and physical properties during and after the irradiation. These materials are candidates for the construction of different parts of the ITER (International Thermonuclear Experimental Reactor) fusion reactor and of the long-term DEMO (DEMOnstration) reactor. The objectives of research at SCK-CEN in this area are: (1) to irradiate RAFM (Reduced Activity Ferritic Martensitic) steel joints and RAFM ODS (Oxide Dispersion Strengthening) at 300 degrees Celsius up to 2 dpa; (2) to irradiate RAFM steel and different FeCr alloys at 300 degrees C above 1.5 dpa; (3) to irradiate Beryllium and Tungsten specimen at 300 degress C up to 0.75 dpa; (4) to irradiate copper/stainless steel joints at 150 degrees C up to 0.1 dpa; (5) to perform in-situ creep-fatigue tests with CuCrZr specimens under neutron irradiation

  16. Food irradiation 2009

    Food irradiation principles; its main applications, advantages and limitations; wholesomeness, present activities at Ezeiza Atomic Centre; research coordinated by the International Atomic Energy Agency; capacity building; and some aspects on national and international regulations, standards and commercialization are briefly described. At present 56 countries authorize the consumption of varied irradiated foods; trade is performed in 32 countries, with about 200 irradiation facilities. Argentina pioneered nuclear energy knowledge and applications in Latin America, food irradiation included. A steady growth of food industrial volumes treated in two gamma facilities can be observed. Food industry and producers show interest towards new facilities construction. However, a 15 years standstill in incorporating new approvals in the Argentine Alimentary Code, in spite of consecutive request performed either by CNEA or some food industries restricts, a wider industrial implementation, which constitute a drawback to future regional commercialization in areas such as MERCOSUR, where Brazil since 2000 freely authorize food irradiation. Besides, important chances in international trade with developed countries will be missed, like the high fresh fruits and vegetables requirements United States has in counter-season, leading to convenient sale prices. The Argentine food irradiation facilities have been designed and built in the country. Argentina produces Cobalt-60. These capacities, unusual in the world and particularly in Latin America, should be protected and enhanced. Being the irradiation facilities scarce and concentrated nearby Buenos Aires city, the possibilities of commercial application and even research and development are strongly limited for most of the country regions. (author)

  17. Economics of Food Irradiation

    This paper reviews and evaluates current developments relating to the prospects for commercial food irradiation within the United States. The study, recognizes that one cannot generalize about the prospects for food irradiation either by process or product. Both technical and economic potentials vary widely for different food products subjected to the same or different types of treatment. Food irradiation processes and products are evaluated. Recent studies concerned with the economics of food irradiation are briefly reviewed and evaluated and findings and conclusions relating to economic potentials summarized. Industry reactions to a proposed pilot plant meat irradiator, sponsored by the U.S. Army and U.S. AEC and coordinated by the Department of Commerce, are discussed and factors which will determine the future direction, extent and commercial success of food preservation by ionizing irradiation are analysed. Developments in all these categories are essential for success, and if not achieved would be limiting factors. Nevertheless, the successful and profitable marketing of irradiated foods must finally be dependent upon customer acceptance and favourable cost versus benefit relations. Benefits will include lower costs and higher profits through spoilage reductions, extensions of shelf-life and shipping distances, market expansions, and quality Improvements. Ultimately, the economic success of this new technology must depend upon the clear demonstration that these benefits will exceed the additional processing costs by a margin sufficient to induce the necessary private investments and willingness to accept related risks in this new field. (author)

  18. Irradiation-Induced Nanostructures

    Birtcher, R.C.; Ewing, R.C.; Matzke, Hj.; Meldrum, A.; Newcomer, P.P.; Wang, L.M.; Wang, S.X.; Weber, W.J.

    1999-08-09

    This paper summarizes the results of the studies of the irradiation-induced formation of nanostructures, where the injected interstitials from the source of irradiation are not major components of the nanophase. This phenomena has been observed by in situ transmission electron microscopy (TEM) in a number of intermetallic compounds and ceramics during high-energy electron or ion irradiations when the ions completely penetrate through the specimen. Beginning with single crystals, electron or ion irradiation in a certain temperature range may result in nanostructures composed of amorphous domains and nanocrystals with either the original composition and crystal structure or new nanophases formed by decomposition of the target material. The phenomenon has also been observed in natural materials which have suffered irradiation from the decay of constituent radioactive elements and in nuclear reactor fuels which have been irradiated by fission neutrons and other fission products. The mechanisms involved in the process of this nanophase formation are discussed in terms of the evolution of displacement cascades, radiation-induced defect accumulation, radiation-induced segregation and phase decomposition, as well as the competition between irradiation-induced amorphization and recrystallization.

  19. Irradiation in action

    The extent to which food irradiation takes place and the regulations governing the process in America, Brazil, Chile, and European countries is reported. The development and operation of a pilot plant built in Holland to test the application of the process to the sterilization of medical supplies and certain foods and the setting up and operation, by Gammester, of a special food irradiation plant in 1982, is described. In this plant 36 foods, mainly dry ingredients such as spices, dried vegetables, egg powder and blood proteins are irradiated. Research looks promising for the future. The implementation of international legal acceptance and more public information is stressed. (U.K.)

  20. Alaskan Commodities Irradiation Project

    The ninety-ninth US Congress commissioned a six-state food irradiation research and development program to evaluate the commercial potential of this technology. Hawaii, Washington, Iowa, Oklahoma and Florida as well as Alaska have participated in the national program; various food products including fishery products, red meats, tropical and citrus fruits and vegetables have been studied. The purpose of the Alaskan study was to review and evaluate those factors related to the technical and economic feasibility of an irradiator in Alaska. This options analysis study will serve as a basis for determining the state's further involvement in the development of food irradiation technology. 40 refs., 50 figs., 53 tabs

  1. Facts about food irradiation: Irradiated foods and the consumer

    This fact sheet discusses market testing of irradiate food, consumer response to irradiated products has always been positive, and in some countries commercial quantities of some irradiated food items have been sold on a regular basis. Consumers have shown no reluctance to buy irradiated food products. 4 refs

  2. Packing for food irradiation

    Joint FAO/IAEA/WHO Expert Committee approved the use of radiation treatment of foods. Nowadays food packaging are mostly made of plastics, natural or synthetic, therefore effect of irradiation on these materials is crucial for packing engineering for food irradiation technology. By selecting the right polymer materials for food packaging it can be ensured that the critical elements of material and product performance are not compromised. When packaging materials are in contact with food at the time of irradiation that regulatory approvals sometimes apply. The review of the R-and-D and technical papers regarding material selection, testing and approval is presented in the report. The most information come from the USA where this subject is well elaborated, the International Atomic Energy Agency (IAEA) reports are reviewed as well. The report can be useful for scientists and food irradiation plants operators. (author)

  3. Food irradiation : ACA inquiry

    The executive summary of the report on food irradiation by the Australian Consumers' Association is presented. The key issues which emerged during the inquiry are summarised including safety controls, wholesomeness, the environment, consumer rights and economic considerations

  4. Sterilization by gamma irradiation

    Since 1980 the National Institute of Nuclear Research counts with an Industrial Gamma Irradiator, for the sterilization of raw materials and finished products. Through several means has been promoted the use of this technology as alternative to conventional methods of sterilization as well as steam treatment and ethylene oxide. As a result of the made promotion this irradiator has come to its saturation limit being the sterilization irradiation one of the main services that National Institute of Nuclear Research offers to producer enterprises of disposable materials of medical use also of raw materials for the elaboration of cosmetic products and pharmaceuticals as well as dehydrated foods. It is presented the trend to the sterilization service by irradiation showed by the compilation data in a survey made by potential customers. (Author)

  5. Economics of food irradiation.

    Deitch, J

    1982-01-01

    This article examines the cost competitiveness of the food irradiation process. An analysis of the principal factors--the product, physical plant, irradiation source, and financing--that impact on cost is made. Equations are developed and used to calculate the size of the source for planned product throughput, efficiency factors, power requirements, and operating costs of sources, radionuclides, and accelerators. Methods of financing and capital investment are discussed. A series of tables show cost breakdowns of sources, buildings, equipment, and essential support facilities for both a cobalt-60 and a 10-MeV electron accelerator facility. Additional tables present irradiation costs as functions of a number of parameters--power input, source size, dose, and hours of annual operation. The use of the numbers in the tables are explained by examples of calculations of the irradiation costs for disinfestation of grains and radicidation of feed. PMID:6759046

  6. Food irradiation in perspective

    Food irradiation already has a long history of hopes and disappointments. Nowhere in the world it plays the role that it should have, including in the much needed prevention of foodborne diseases. Irradiated food sold well wherever consumers were given a chance to buy them. Differences between national regulations do not allow the international trade of irradiated foods. While in many countries food irradiation is still illegal, in most others it is regulated as a food additive and based on the knowledge of the sixties. Until 1980, wholesomeness was the big issue. Then the ''prerequisite'' became detection methods. Large amounts of money have been spent to design and validate tests which, in fact, aim at enforcing unjustified restrictions on the use of the process. In spite of all the difficulties, it is believed that the efforts of various UN organizations and a growing legitimate demand for food safety should in the end lead to recognition and acceptance. (Author)

  7. Food irradiation in perspective

    Henon, Y. M.

    1995-02-01

    Food irradiation already has a long history of hopes and disappointments. Nowhere in the world it plays the role that it should have, including in the much needed prevention of foodborne diseases. Irradiated food sold well wherever consumers were given a chance to buy them. Differences between national regulations do not allow the international trade of irradiated foods. While in many countries food irradiation is still illegal, in most others it is regulated as a food additive and based on the knowledge of the sixties. Until 1980, wholesomeness was the big issue. Then the "prerequisite" became detection methods. Large amounts of money have been spent to design and validate tests which, in fact, aim at enforcing unjustified restrictions on the use of the process. In spite of all the difficulties, it is believed that the efforts of various UN organizations and a growing legitimate demand for food safety should in the end lead to recognition and acceptance.

  8. Innovations in irradiator design

    In the past few years industry has demanded certain changes in irradiator design to meet the needs of the medical manufacturers, and as well service the requirements of new applications for irradiation. The medical manufacturers have, in certain cases, been tending toward larger capacity machines with higher efficiencies to take advantage of economies of scale. Other parts of the industry have been demanding a truly ''Multipurpose'' facility which can process many varied types of products. Coupled with these machine changes there has been an increase in demand for more comprehensive logging of the irradiation process. This has spawned development of several styles of computer monitoring, control and logging systems. This paper will discuss these topics in more detail in order to give some insight into the ''state of the art'' within the irradiator design industry. (author)

  9. Dosimetry for food irradiation

    A Manual of Food Irradiation Dosimetry was published in 1977 under the auspices of the IAEA as Technical Reports Series No. 178. It was the first monograph of its kind and served as a reference in the field of radiation processing and in the development of standards. While the essential information about radiation dosimetry in this publication has not become obsolete, other publications on radiation dosimetry have become available which have provided useful information for incorporation in this updated version. There is already a Codex General Standard for Irradiated Foods and an associated Code of Practice for Operation of Irradiation Facilities used for Treatment of Food, issued in 1984 by the Codex Alimentarius Commission of the FAO/WHO Food Standard Programme. The Codex Standard contains provisions on irradiation facilities and process control which include, among other requirements, that control of the processes within facilities shall include the keeping of adequate records including quantitative dosimetry. Appendix A of the Standard provides an explanation of process control and dosimetric requirements in compliance with the Codex Standard. By 1999, over 40 countries had implemented national regulations or issued specific approval for certain irradiated food items/classes of food based on the principles of the Codex Standard and its Code of Practice. Food irradiation is thus expanding, as over 30 countries are now actually applying this process for the treatment of one or more food products for commercial purposes. Irradiated foods are being marketed at retail level in several countries. With the increasing recognition and application of irradiation as a sanitary and phytosanitary treatment of food based on the provisions of the Agreement on the Application of Sanitary and Phytosanitary Measures of the World Trade Organization, international trade in irradiated food is expected to expand during the next decade. It is therefore essential that proper dosimetry

  10. Irradiation of chilled lamb

    Chilled, vacuum-packed New Zealand lamb loins have been irradiated at doses between 1-8 kGy. The report outlines the methods used and provides dosimetry details. An appendix summarises the results of a taste trial conducted on the irradiated meat by the Meat Industry Research Institute of New Zealand. This showed that, even at 1 kGy, detectable flavours were induced by the radiation treatment

  11. Food irradiation in Malaysia

    Food irradiation has recently been visited as a technology that can contribute to the solution of problems associated with food preservation of Malaysia's agriculture produce and products thereby improving the economic status of the rural sector. However, the history of food irradiation in Malaysia is very recent. Research carried out on food irradiation only began in 1974 as a result of the installation of a 60Co facility (initially 10,000 Ci) at the National University of Malaysia. Since its installation several studies have been carried out pertaining to the food irradiation. Presently its development has been slow. Research in this area has been confined to laboratory scale and purely academic. This limitation is due to a number of reasons, among others are: a) limited number of facilities; b) lack of expertise to conduct its research; c) other preservation methods can be improved with lower capital output. An important step towards its development was made when Malaysia actively participated in the RCA/IAEA food irradiation project, viz. the irradiation of pepper which was carried out at the National University of Malaysia in the 80's. As a result of this venture, research and development activities in food irradiation have been geared toward semi-plot scale with the view ot commercialization in the future. In 1982, a group of researchers was formed to conduct feasibility studies using irradiation techniques in trying to overcome several problems associated with our local paddy and rice. Another group is being organized by the National University of Malaysia to look into the problems associated with the preservation of frozen shrimps. (author)

  12. Fully portable blood irradiator

    A fully portable blood irradiator was developed using the beta emitter thulium-170 as the radiation source and vitreous carbon as the body of the irradiator, matrix for isotope encapsulation, and blood interface material. These units were placed in exteriorized arteriovenous shunts in goats, sheep, and dogs and the effects on circulating lymphocytes and on skin allograft retention times measured. The present work extends these studies by establishing baseline data for skin graft rejection times in untreated animals

  13. Proton irradiation of EMCCDs

    Smith, DR; Ingley, R.; Holland, AD

    2006-01-01

    This paper describes the irradiation of 95 electron multiplication charge coupled devices (EMCCDs) at the Paul Scherrer Institut (PSI) in Switzerland, to investigate the effects of proton irradiation on the operational characteristics of CCDs featuring electron multiplication technology for space use. This work was carried out in support of the CCD development for the radial velocity spectrometer (RVS) instrument of the European Space Agency's cornerstone Gaia mission. Previous proton irradia...

  14. Irradiation Defects in Silicon Crystal

    2003-01-01

    The application of irradiation in silicon crystal is introduced.The defects caused by irradiation are reviewed and some major ways of studying defects in irradiated silicon are summarized.Furthermore the problems in the investigation of irradiated silicon are discussed as well as its properties.

  15. Irradiated produce reaches Midwest market

    In March 1992, the Chicago-area store gave its shoppers a choice between purchasing irradiated and nonirradiated fruits. The irradiated fruits were treated at Vindicator Inc., the first U.S. food irradiation facility (starting up on January 10, 1992). The plant, located in Mulberry, Fla., then shipped the fruits in trucks to the store where they were displayed under a hand-lettered sign describing the irradiated fruits and showing the irradiation logo

  16. Irradiation of cane sugar spirit

    The present study deals with the effect of irradiation on the gas-chromatographic profile of irradiated cane sugar spirit irradiated in glass containers in the presence of oak chops with doses of 0-10 kGy. Volatile constituents were analyzed in a CG gas chromatographer with a flame ionization detector using a Megabore CG-745 column. The results are discussed considering the contribution of irradiation to the quality of the spirit and the contribution of the irradiated oak wood. (author)

  17. Consumer response to irradiated foods

    Apart from the safety and nutritional adequacy of irradiated foods, consumer acceptance would be a major factor in the successful commercialization of irradiation technology. One way to remove the misconceptions about irradiated foods is to serve the food items prepared from irradiated foods to consumers and gauge their response. To evaluate the public perception on irradiated foods, a survey was conducted in various scientific symposia and Bhabha Atomic Research Centre canteens covering a wide spectrum of consumers

  18. Longevity of irradiated burros

    During the course of external radiation exposures of burros to establish a dose-response curve for acute mortality after total irradiation, some of the animals at the three lowest exposures to gamma photons survived. These groups of 10, 9, and 10 burros were exposed to 320, 425, and 545 R, respectively. There were 10 unirradiated controls. In 1953, 20 burros were exposed to 375 R (gamma) in 25-R/week increments without acute mortality and were added to the life-span study. In 1957, 33 burros were exposed to mixed neutron-gamma radiation from nuclear weapons, and 14 controls were added. The total number of irradiated burros in the study was increased to 88 by the addition of 6 animals irradiated with 180 rads of neutron and gamma radiation (4:1) in a Godiva-type reactor in 1959. In this experiment two acute deaths occurred which were not included in the analysis. In the first 4 years after the single gamma exposures, there were deaths from pancytopenia and thrombocytopenia, obviously related to radiation-induced bone-marrow damage. After that period, however, deaths were from common equine diseases; no death has resulted from a malignant neoplasm. Of the original 112 burros, 15 survive (10 irradiated and 5 controls). Survival curves determined for unirradiated and neutron-gamma- and gamma-irradiated burros showed significant differences. The mean survival times were: controls, 28 years; gamma irradiation only, 26 years; and neutron-gamma irradiation, 23 years. 3 refs., 4 figs., 1 tab

  19. Compréhension et modélisation de la rupture fragile des aciers renforcés par nano-précipitation : effets de texture, de vieillissement et de composition

    Rouffié, Anne-Laure

    2014-01-01

    The Oxide Dispersion Strengthened (ODS) steels have been identified as potential materials for fuel cladding in Generation IV nuclear reactors. They are characterized by a very good resistance to swelling under irradiation and to high temperature creep, but questions still remain about the impact toughness of these materials. The first aim of this work is to understand the effects of different parameters (chemical composition, texture, thermal ageing...) on the impact behaviour of ODS steels....

  20. Gamma Irradiation does not Cause Carcinogenesis of Irradiated Herbs

    Full text: Microbial contamination of medicinal herbs can be effectively reduced by gamma irradiation. Since irradiation may cause carcinogenicity of the irradiated herbs, the objective of this research is to study the effect of gamma irradiation (10 and 25 kGy) from cobalt-60 on carcinogenicity. The herbs studied were Pueraria candollei Grah., Curcuma longa Linn. Zingiber montanum, Senna alexandrina P. Miller, Eurycoma Longifolia Jack, Gymnostema pentaphylum Makino, Ginkgo biloba, Houttuynia cordata T., Andrographis paniculata, Thunbergia laurifolia L., Garcinia atroviridis G., and Cinnamomum verum J.S.Presl. The results showed that gamma irradiation at the dose of 10 and 25 kGy did not cause carcinogenicity of the irradiated herbs

  1. ORNL irradiation creep facility

    A machine was developed at ORNL to measure the rates of elongation observed under irradiation in stressed materials. The source of radiation is a beam of 60 MeV alpha particles from the Oak Ridge Isochronous Cyclotron (ORIC). This choice allows experiments to be performed which simulate the effects of fast neutrons. A brief review of irradiation creep and experimental constraints associated with each measurement technique is given. Factors are presented which lead to the experimental choices made for the Irradiation Creep Facility (ICF). The ICF consists of a helium-filled chamber which houses a high-precision mechanical testing device. The specimen to be tested must be thermally stabilized with respect to the temperature fluctuations imposed by the particle beam which passes through the specimen. Electrical resistance of the specimen is the temperature control parameter chosen. Very high precision in length measurement and temperature control are required to detect the small elongation rates relevant to irradiation creep in the test periods available (approx. 1 day). The apparatus components and features required for the above are presented in some detail, along with the experimental procedures. The damage processes associated with light ions are discussed and displacement rates are calculated. Recent irradiation creep results are given, demonstrating the suitability of the apparatus for high resolution experiments. Also discussed is the suitability of the ICF for making high precision thermal creep measurements

  2. Post-irradiation diarrhea

    In radiotherapy of pelvic cancers, the X-ray dose to be delivered to the tumour is limited by the tolerance of healthy surrounding tissue. In recent years, a number of serious complications of irradiation of pelvic organs were encountered. Modern radiotherapy necessitates the acceptance of a calculated risk of complications in order to achieve a better cure rate. To calculate these risks, one has to know the radiation dose-effect relationship of normal tissues. Of the normal tissues most at risk when treating pelvic tumours only the bowel is studied. In the literature regarding post-irradiation bowel complications, severe and mild complications are often mixed. In the present investigation the author concentrated on the group of patients with relatively mild symptoms. He studied the incidence and course of post-irradiation diarrhea in 196 patients treated for carcinoma of the uterine cervix or endometrium. The aims of the present study were: 1) to determine the incidence, course and prognostic significance of post-irradiation diarrhea; 2) to assess the influence of radiotherapy factors; 3) to study the relation of bile acid metabolism to post-irradiation diarrhea; 4) to investigate whether local factors (reservoir function) were primarily responsible. (Auth.)

  3. ORNL irradiation creep facility

    Reiley, T.C.; Auble, R.L.; Beckers, R.M.; Bloom, E.E.; Duncan, M.G.; Saltmarsh, M.J.; Shannon, R.H.

    1980-09-01

    A machine was developed at ORNL to measure the rates of elongation observed under irradiation in stressed materials. The source of radiation is a beam of 60 MeV alpha particles from the Oak Ridge Isochronous Cyclotron (ORIC). This choice allows experiments to be performed which simulate the effects of fast neutrons. A brief review of irradiation creep and experimental constraints associated with each measurement technique is given. Factors are presented which lead to the experimental choices made for the Irradiation Creep Facility (ICF). The ICF consists of a helium-filled chamber which houses a high-precision mechanical testing device. The specimen to be tested must be thermally stabilized with respect to the temperature fluctuations imposed by the particle beam which passes through the specimen. Electrical resistance of the specimen is the temperature control parameter chosen. Very high precision in length measurement and temperature control are required to detect the small elongation rates relevant to irradiation creep in the test periods available (approx. 1 day). The apparatus components and features required for the above are presented in some detail, along with the experimental procedures. The damage processes associated with light ions are discussed and displacement rates are calculated. Recent irradiation creep results are given, demonstrating the suitability of the apparatus for high resolution experiments. Also discussed is the suitability of the ICF for making high precision thermal creep measurements.

  4. Irradiation of grains and spices

    The efficacy of food irradiation to extend the storage life and improve the hygienic quality of rice, mungbean and spices was tested by direct involvement with related food industries. The test consisted of storage trials of irradiated rice under commercial conditions, market testing of irradiated food, and a trial irradiation of commercial products. A consumer acceptance test was conducted using a group of educated people from 3 universities. To prove the safety of food irradiation conducted under appropriately controlled conditions, additional data on vitamin B content and the physico-chemical properties of irradiated rice, as well as free radical activity in irradiated rice, mungbean and spices were collected during this study. The results indicated that rice packaged in polyethylene pouch and irradiated up to 1 kGy could be stored for more than 1 year without insect damage. The colour of irradiated rice was slightly darker than that of unirradiated control, but was still acceptable. The vitamin B content of rice irradiated with such a dose was not significantly changed. Many food companies have recognized the ability of food irradiation, but this technology is not well understood by the general public. An irradiation dose of 3 kGy can be recommended as maximum dose to decontaminate rice of certain bacteria. Free radicals produced in irradiated rice, mungbean and spice will disappear within 1 month following irradiation. (author). 10 refs, 2 figs, 10 tabs

  5. Dosimetry of neutron irradiations

    Biological dosimetry of neutron irradiation appears to be of great difficulty due to the multiparametric aspect of the relative biological effectiveness and the heterogeneity of the neutron dose distribution. Dosimetry by sodium 24 activation which can be performed by means of portable radiameters appears to be very useful for early triage within the 3 h following neutron irradiation, whereas hematological dosimetry by slope and level analysis of the lymphocyte drop cannot be used in this case. Chromosomic aberration analysis allows to evaluate the neutron dose heterogeneity by the frequency measurement of acentric fragments not originating from the formation of dicentrics or rings. Finally, recent experimental data on large primate models (baboons) have shown that some plasma hemostasia factors appear to be reliable biological indicators and noticeable markers of the prognosis of neutron irradiation

  6. The Birmingham Irradiation Facility

    At the end of 2012 the proton irradiation facility at the CERN PS will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1×1 cm2) silicon sensors

  7. Neutron irradiation of seeds

    Neutrons are a valuable type of ionizing radiation for seed irradiation and radiobiological studies and for inducing mutations in crop plants. In experiments where neutrons are used in research reactors for seed irradiation it is difficult to measure the dose accurately and therefore to establish significant comparisons between experimental results obtained in various reactors and between repeated experiments in the same reactor. A further obstacle lies in the nature and response of the seeds themselves and the variety of ways in which they are exposed in reactors. The International Atomic Energy Agency decided to initiate international efforts to improve and standardize methods of exposing seeds in research reactors and of measuring and reporting the neutron dose. For this purpose, an International Neutron Seed Irradiation Programme has been established. The present report aims to give a brief but comprehensive picture of the work so far done in this programme. Refs, figs and tabs

  8. The Birmingham Irradiation Facility

    Dervan, P; Hodgson, P; Marin-Reyes, H; Wilson, J

    2013-01-01

    At the end of 2012 the proton irradiation facility at the CERN PS [1] will shut down for two years. With this in mind, we have been developing a new ATLAS scanning facility at the University of Birmingham Medical Physics cyclotron. With proton beams of energy approximately 30 MeV, fluences corresponding to those of the upgraded Large Hadron Collider (HL-LHC) can be reached conveniently. The facility can be used to irradiate silicon sensors, optical components and mechanical structures (e.g. carbon fibre sandwiches) for the LHC upgrade programme. Irradiations of silicon sensors can be carried out in a temperature controlled cold box that can be scanned through the beam. The facility is described in detail along with the first tests carried out with mini (1 x 1 cm^2 ) silicon sensors.

  9. Irradiation induced kyphosis

    Eighty-one patients with Wilms tumor treated by irradiation and chemotherapy were studied. Despite the fact that multiple portals for irradiation were used, each crossing the midline, the amount of irradiation delivered to different parts of the vertebral body varied and it was this variation in delivered dose which produced axial skeletal deformities in 70% of the patients. Of the 57 patients with these deformities, 32 had scoliosis, 22 kyphoscoliosis and 3 patients pure kyphosis; 12 patients had a kyphotic deformity of over 25 degrees, 7 patients requiring surgical correction. A high incidence of pseudarthrosis following posterior fusion has led to the preference of a 2-stage procedure, anterior interbody fusion followed by a posterior fusion with Harrington rods after 2 weeks of correction in halo femoral traction

  10. Irradiation induced kyphosis

    Riseborough, E.J.

    1977-10-01

    Eighty-one patients with Wilms tumor treated by irradiation and chemotherapy were studied. Despite the fact that multiple portals for irradiation were used, each crossing the midline, the amount of irradiation delivered to different parts of the vertebral body varied and it was this variation in delivered dose which produced axial skeletal deformities in 70% of the patients. Of the 57 patients with these deformities, 32 had scoliosis, 22 kyphoscoliosis and 3 patients pure kyphosis; 12 patients had a kyphotic deformity of over 25 degrees, 7 patients requiring surgical correction. A high incidence of pseudarthrosis following posterior fusion has led to the preference of a 2-stage procedure, anterior interbody fusion followed by a posterior fusion with Harrington rods after 2 weeks of correction in halo femoral traction.

  11. Food irradiation - general aspects

    This paper describes research and development experience in food irradiation followed by commercial utilisation of multi-purpose plants. The main design objectives should be high efficiency and uniform dose. Particular care must be given to dosimetry and the use of plastic dosimeters is described. Capital outlay for a 1 MCi Cobalt 60 irradiator is estimated to be 2.5 million dollars giving a unit processing cost of 0.566 dollars/ft3 of throughput for 8000 hour/year use at a dose of 25 kGy. (2.5 Mrad). The sale of irradiated food for human consumption in Britain is not yet permitted but it is expected that enabling legislation will be introduced towards the end of 1985

  12. Food irradiation and the chemist

    Food Irradiation and the Chemist reviews the chemical challenges facing the food industry regarding food irradiation, especially in the key area of detection methodology. The book looks at the most promising techniques currently available for the detection of irradiated foods and discusses their suitability to different food groups. It also covers the latest work on the effect of irradiation on polymer additives, potential taint from irradiated food contact plastics, the effects of irradiation on micro-organisms and their biochemistry, and much more... (author)

  13. Effects of irradiation

    The midday depression of CO2 assimilation in leaves of two cultivars of hazelnut. Effect of UV-B radiation on decay kinetics of long-term delayed luminiscence of green algae Scenedesmus quadricuda. Effects of irradiance on biomass allocation and needle photosynthetic capacity in silver fir seedlings originating from different localities. Chlorophyll fluorescence of UV-B irradiated bean leaves subjected to chilling in light. Preliminary studies on susceptibility of selected varieties of oats to high UV-B radiation dose. Influence of light conditions on oxidative stress in maize callus

  14. Irradiation of dehydrated vegetables

    The reason for radurization was to decreased the microbial count of dehydrated vegetables. The average absorbed irradiation dose range between 2kGy and 15kGy. The product catagories include a) Green vegetables b) White vegetables c) Powders of a) and b). The microbiological aspects were: Declining curves for the different products of T.P.C., Coliforms, E. Coli, Stap. areus, Yeast + Mold at different doses. The organoleptical aspects were: change in taste, flavour, texture, colour and moisture. The aim is the marketing of irradiated dehydrated vegetables national and international basis

  15. Irradiated cocoa beans

    Groups of 40 male and 40 female CD rats were fed powdered rodent diet containing 25% (w/w) of either non-irradiated, irradiated or fumigated cocoa beans. The diets were supplemented with certain essential dietary constituents designed to satisfy normal nutritional requirements. An additional 40 male and 40 female rats received basal rodent diet alone (ground) and acted as an untreated control. After 70 days of treatment, 15 male and 15 female rats from each group were used to assess reproductive function of the F0 animals and growth and development of the F1 offspring up to weaning; the remaining animals were killed after 91 days of treatment. (orig.)

  16. Materials response to irradiation

    Radiation-induced changes in the mechanical properties of metals, e.g. due to the embrittlement necessitate irradiation experiments with HTR-specific neutron spectra. These experiments help to determine materials behaviour and establish basic data for design and safety testing, especially with a view to the high fluence and temperature loads on absorber cans. The experiments are carried out up to maximum operational fluence (>= 1022nsub(th)/cm2). Results so far have shown the importance of the materials structure for assurance of sufficient residual ductility after irradiation. Secondary experiments, e.g. on He implantation and radiation response of the absorber material B4C, are mentioned. (orig.)

  17. Food irradiation processing

    An international symposium on food irradiation processing dealing with issues which affect the commercial introduction of the food irradiation process was held in Vienna in 1985. The symposium, which attracted close to 300 participants, was planned to interest not only scientists and food technologists, but also representatives of government agencies, the food industry, trade associations and consumer organizations. The symposium included a discussion of the technological and economic feasibility of applying ionizing energy for the preservation of food, and focused on the specific needs of developing countries. Separate abstracts were prepared for the various presentations at this meeting

  18. Serum magnesium and irradiation

    Serum magnesium determinations were obtained on 10 dogs and 11 patients undergoing fractionated irradiation to the pelvis and lower abdomen. Five of the dogs received oral prednisone during irradiation. There was no significant change in magnesium concentration in either the control dogs or the patients, but there was a significant increase in stool frequency in both the dogs and patients. A significant increase in magnesium concentration was noted in the dogs receiving prednisone. It is concluded that radiation-induced diarrhea is not caused by reduced serum magnesium concentration

  19. Canadian Irradiation Centre

    The Canadian Irradiation Centre is a non-profit cooperative project between Atomic Energy of Canada Limited, Radiochemical Company and Universite du Quebec, Institut Armand-Frappier, Centre for Applied Research in Food Science. The Centre's objectives are to develop, demonstrate and promote Canada's radiation processing technology and its applications by conducting applied research; training technical, professional and scientific personnel; educating industry and government; demonstrating operational and scientific procedures; developing processing procedures and standards, and performing product and market acceptance trials. This pamphlet outlines the history of radoation technology and the services offered by the Canadian Irradiation Centre

  20. Facts about food irradiation: Nutritional quality of irradiated foods

    This fact sheet briefly considers the nutritional value of irradiated foods. Micronutrients, especially vitamins, are sensitive to any food processing method, but irradiation does not cause any special nutritional problems in food. 4 refs

  1. Soudage par explosion thermique sous charge de cermets poreux à base de TiC-Ni sur substrat en acier-comportement tribologique Welding of porous TiC–Ni based cermets on substrate steel by thermal explosion under load-tribological behaviour

    Lemboub Samia

    2013-11-01

    Full Text Available Dans ce travail, nous nous intéressons à l'élaboration de cermets à base de TiC-Ni par dispersion de particules de carbures, oxydes ou borures dans une matrice de nickel, grâce à la technique de l'explosion thermique sous une charge de 20 MPa. La combustion de mélanges actifs (Ti-C-Ni-An où An = Al2O3, MgO, SiC, TiB2, WC, basée sur la réaction de synthèse de TiC (ΔHf298K = −184 kJ/mole, génère des cermets complexes. Un court maintien sous charge du cermet à 1373 K, après l'explosion thermique, permet son soudage sur un substrat en acier XC55. Les cermets obtenus dans ces conditions demeurent poreux et conservent une porosité de l'ordre de 25–35 %. La densité relative du cermet, sa dureté et son comportement tribologique, dépendront de la nature de l'addition dans les mélanges de départ. Porous TiC-Ni based cermets were obtained by dispersion of carbides, oxides or borides particles in a nickel matrix thanks to the thermal explosion technique realized under a load of 20 MPa. The combustion of active mixtures (Ti-C-Ni-An where An = Al2O3, MgO, SiC, TiB2 or WC based on the titanium carbide reaction synthesis (ΔHf = −184 kJ/mol, generates porous complex cermets. After the thermal explosion, a short maintenance under load at 1373 K of the combustion product, allows at the same time the cermets welding on a carbon steel substrate. The obtained cermets under these conditions preserve a porosity of about 25–35%. The relative density, hardness and tribological behaviour of the complex cermets depend on the additions nature (An in the starting mixtures.

  2. Consumer opinions in Argentina on food irradiation: irradiated onions

    Two surveys were carried out in Buenos Aires of consumer attitudes towards irradiated onions [no data given]. The first investigated the general level of consumer knowledge concerning food irradiation, whilst the second (which covered consumers who had actually bought irradiated onions) examined reasons for purchase and consumer satisfaction. Results reveal that more than 90% of consumers surveyed had a very limited knowledge of food irradiation

  3. Economics of gamma irradiation processing

    The gamma-ray irradiation business started at the Takasaki Laboratory of Japan Atomic Energy Research Institute. The irradiation facilities were constructed thereafter at various sites. The facilities must accept various types of irradiation, and must be constructed as multi-purpose facilities. The cost of irradiation consists of the cost of gamma sources, construction expense, personnel expense, management expense, and bank interest. Most of the expenses are considered to be fixed expense, and the amount of irradiation treatment decides the original costs of work. The relation between the irradiation dose and the construction expense shows the larger facility is more economical. The increase of amount of treatment reduces the original cost. The utilization efficiency becomes important when the amount of treatment and the source intensity exceed some values. The principal subjects of gamma-ray irradiation business are the sterilization of medical tools and foods for aseptic animals, the improvement of quality of plastic goods, and the irradiation of foods. Among them, the most important subject is the sterilization of medical tools. The cost of gamma irradiation per m3 in still more expensive than that by ethylene oxide gas sterilization. However, the demand of gamma-ray irradiation is increasing. For the improvement of quality of plastic goods, electron irradiation is more favourable than the gamma irradiation. In near future, the economical balance of gamma irradiation can be achieved. (Kato, T.)

  4. Food irradiation and consumer values

    A mail survey technique was used to determine if value hierarchy, locus of control, innovativeness, and demographic parameters could distinguish between subjects expressing different levels of concern and willingness to buy irradiated food. Concern toward irradiated food was lower than concern for other food safety issues, probably because many expressed uncertainty regarding irradiation. Those ranking the value “an ecologically balanced world” expressed the greatest irradiation concern. Factors which could predict high irradiation concern were being highly concerned about the use of chemical sprays on food, completing more formal education and being female; those believing that life was controlled by luck were less concerned. Irradiation concern was a principal factor determining willingness to buy irradiated foods. Innovative consumers were more likely to try irradiated foods than noninnovative. Implications for consumer education are presented

  5. Regulatory aspect of food irradiation

    Interest in the process of food irradiation is reviewed once again internationally. Although food irradiation has been thoroughly investigated, global acceptance is still lacking. Factors which impede the progress of the technology are discussed here. (author)

  6. Phytosanitary Applications of Irradiation

    Phytosanitary treatments are used to disinfest agricultural commodities of quarantine pests so that the commodities can be shipped out of quarantined areas. Ionizing irradiation is a promising phytosanitary treatment that is increasing in use worldwide. Almost 19 000 metric tons of sweet potatoes and several fruits plus a small amount of curry leaf are irradiated each year in 6 countries, including the United States, to control a number of plant quarantine pests. Advantages over other treatments include tolerance by most fresh commodities, ability to treat in the final packaging and in pallet loads, and absence of pesticide residues. Disadvantages include lack of acceptance by the organic food industries and logistical bottlenecks resulting from current limited availability of the technology. A regulatory disadvantage is lack of an independent verification of treatment efficacy because pests may be found alive during commodity inspection, although they will not complete development or reproduce. For phytosanitary treatments besides irradiation, the pests die shortly after the treatment is concluded. This disadvantage does not hamper its use by industry, but rather makes the treatment more difficult to develop and regulate. Challenges to increase the use of phytosanitary irradiation (PI) are cost, because commercial use has not yet reached an optimum economy of scale, lack of facilities, because of their cost and current inability to feasibly locate them in packing facilities, lack of approved treatments for some quarantine pests, and concern about the process by key decision makers, such as packers, shippers, and retailers. Methods for overcoming these challenges are discussed. (author)

  7. Irradiation of spices

    The problem faced by spice producing countries and by the food industry using these spices as ingredients are facing the problem of their high contamination with pathogenic and non pathogenic microorganisms, which create public health and product-deterioration problems. After discussing the conventional methods of decontamination, which result either in organoleptic losses (heat and extracts) or in toxic residues (fumigants), the advantages of the irradiation treatment are presented. This procedure is direct, simple to administer and control, and highly efficient. Doses of 3-7 kGy have been proven to reduce the microbial load to satisfactory levels, without affecting the organoleptic characteristics, whereas the surviving microflora is more sensitive to the subsequent food processing treatments. Irradiation can be administered in the commercial packages, which leads to considerable energy and personnel savings, while preventing subsequent recontamination. The increasing demand for high microbial quality in spices makes it easier for the food industry to afford the irradiation treatment costs. The wholesomeness of irradiated spices has been demonstrated by a group of experts of WHO, FAO and IAEA, and the treatment has been promulgated by Codex Alimentarius and been cleared by a number of national health authorities, including the U.S. F.D.A. The number of clearances is steadily increasing and so is the commercial use

  8. Solar Irradiance Variability

    Solanki, Sami K

    2012-01-01

    The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation and the solar cycle. A part of the difficulty is that there are no other constant natural daytime sources to which the Sun's brightness can be compared. The discovery of solar irradiance variability rekindled a long-running discussion on how strongly the Sun affects our climate. A non-negligible influence is suggested by correlation studies between solar variability and climate indicators. The mechanism for solar irradiance variations that fits the observations best is that magnetic features at the solar surface, i.e. sunspots, faculae and the magnetic network, are responsible for almost all variations (although on short timescales convection and p-mode oscillations also contribute). In spite of significant progress important questions are still open. Thus there is a debat...

  9. Irradiation effects on zircaloy

    In a water cooled reactor, the neutron effect on zirconium base alloys which are used in the core, is a twofold one: - indirect effect, by means of modifications to the alloy environment; - direct effect occurence of irradiation defects in the material. The indirect effect results in an increase of the water corrosion, as a consequence of the water radiolysis and in stress-corrosion, due to fission products such as iodine, cesium, cadmium... The paper will describe the consequence of these phenomena and the means used to remedy their harmfull effects. The occurence of irradiation defects has three consequence: - Material strenghening: the yield and ultimate stresses are increased by 45 and 35% respectively for the cold worked and stress-relieved zircaloy while the uniform elongation, rather low before irradiation, practically does not decrease (fluence 5.1021 n/cm2). Yield and ultimate stresses of annealed zircaloy are increased by about 150% while uniform elongation decreases from 8 to 1% in the same conditions. - Material growing it is a change in dimensions in the absence of any applied stress. It depends on the cristallography texture, metallurgical state of the material and irradiation temperature. - Material creeping: in the normal working conditions of a reactor, it is the main source of deformation. It depends on temperature, stress, neutron flux and metallurgical state of the material

  10. Wholesomeness of irradiated food

    Raica, Nicholas; McDowell, Marion E.; Darby, William J.

    1963-01-15

    The wholesomeness of irradiated foods was evaluated in mice, rats, dogs, and monkeys over a 2-year period, or 4 generations. Data are presented on the effects of a diet containing radiation-processed foods on growth, reproduction, hematology, histopathology, carcinogenicity, and life span. (86 references) (C.H.)

  11. Photochromism in irradiated diamond

    Photochromism exhibited at low temperatures in the absorption line at 1.521 eV in electron-irradiated type IIb diamond is described and understood in terms of a simple model. Energy and temperature dependences of the photoconversion process are discussed briefly. (author)

  12. Profitability of irradiation plants

    In any industrial process it is seek an attractive profit from the contractor and the social points of view. The use of the irradiation technology in foods allows keep their hygienically, which aid to food supply without risks for health, an increment of new markets and a losses reduction. In other products -cosmetics or disposable for medical use- which are sterilized by irradiation, this process allows their secure use by the consumers. The investment cost of an irradiation plant depends mainly of the plant size and the radioactive material reload that principally is Cobalt 60, these two parameters are in function of the type of products for irradiation and the selected doses. In this work it is presented the economic calculus and the financial costs for different products and capacities of plants. In general terms is determined an adequate utility that indicates that this process is profitable. According to the economic and commercial conditions in the country were considered two types of credits for the financing of this projects. One utilizing International credit resources and other with national sources. (Author)

  13. Update on meat irradiation

    The irradiation of meat and poultry in the United States is intended to eliminate pathogenic bacteria from raw product, preferably after packaging to prevent recontamination. Irradiation will also increase the shelf life of raw meat and poultry products approximately two to three times the normal shelf life. Current clearances in the United States are for poultry (fresh or frozen) at doses from 1.5 to 3.0 kGy and for fresh pork at doses from 0.3 to 1.0 kGy. A petition for the clearance of all red meat was submitted to the Food and Drug Administration (FDA) in July 1994. The petition is for clearances of fresh meat at doses from 1.5 to 4.5 kGy and for frozen meat at ∼2.5 to 7.5 kGy. Clearance for red meat is expected before the end of 1997. There are 28 countries that have food irradiation clearances, of which 18 countries have clearances for meat or poultry. However, there are no uniform categories or approved doses for meat and poultry among the countries that could hamper international trade of irradiated meat and poultry

  14. Radiation irradiation test method

    The present invention provides a method of irradiating radiation (rays) to a test piece by using an actual powder of nuclear fuel material. Namely, the test piece is sealed in an inner and outer double-walled bag of a radiation-permeable polymer film to form an irradiation specimen. The irradiation specimen is placed at a predetermined position of a glove box for a predetermined period of time, and necessary irradiation is performed. The outer bag is cut out, and the test piece in the inner bag not deposited with radioactive material is obtained. This is transported out of the glove box by using a bag-out method. The test piece sealed in the inner bag can be taken out by cutting out the inner bag in an operation hood capable of preventing scattering of radioactive materials. The bag-out method mentioned herein is a method of taking out radioactive materials or materials contaminated by the radioactive materials in the glove box after sealing them in a vinyl chloride bag by welding. (I.S.)

  15. Pituitary irradiation program

    The alpha particle pituitary irradiation program continues to be a major research project at Donner Pavilion. A study to determine the incidence of hyperprolactinemia in a large series of acromegalic subjects was undertaken. The relationships between plasma levels of growth hormone and prolactin, sellar volume, duration of acromegaly, and age at time of evaluation were investigated

  16. Irradiated uranium reprocessing

    Task concerned with reprocessing of irradiated uranium covered the following activities: implementing the method and constructing the cell for uranium dissolving; implementing the procedure for extraction of uranium, plutonium and fission products from radioactive uranium solutions; studying the possibilities for using inorganic ion exchangers and adsorbers for separation of U, Pu and fission products

  17. NSUF Irradiated Materials Library

    Cole, James Irvin [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-01

    The Nuclear Science User Facilities has been in the process of establishing an innovative Irradiated Materials Library concept for maximizing the value of previous and on-going materials and nuclear fuels irradiation test campaigns, including utilization of real-world components retrieved from current and decommissioned reactors. When the ATR national scientific user facility was established in 2007 one of the goals of the program was to establish a library of irradiated samples for users to access and conduct research through competitively reviewed proposal process. As part of the initial effort, staff at the user facility identified legacy materials from previous programs that are still being stored in laboratories and hot-cell facilities at the INL. In addition other materials of interest were identified that are being stored outside the INL that the current owners have volunteered to enter into the library. Finally, over the course of the last several years, the ATR NSUF has irradiated more than 3500 specimens as part of NSUF competitively awarded research projects. The Logistics of managing this large inventory of highly radioactive poses unique challenges. This document will describe materials in the library, outline the policy for accessing these materials and put forth a strategy for making new additions to the library as well as establishing guidelines for minimum pedigree needed to be included in the library to limit the amount of material stored indefinitely without identified value.

  18. Process for irradiation of polyethylene

    Irradiation of polyethylene affects its processabiltiy in the fabrication of products and affects the properties of products already fabricated. The present invention relates to a process for the irradiation of polyethylene, and especially to a process for the irradiation of homopolymers of ethylene and copolymers of ethylene and higher α-olefins, in the form of granules, with low levels of electron or gamma irradiation in the presence of an atomsphere of steam

  19. Economics of Food Irradiation

    To-day very reliable irradiation equipment is available, and for an industrialist it is largely an economic consideration whether he should go in for an otherwise acceptable irradiation processing. In Denmark an industrial concern has now found it economically justifiable to establish a multi-purpose industrial plant, equipped with an American linac, and this facility will be able to process food.l To date, few plants in the world have recorded actual cost experiences for industrial food processing, but cost figures from other fields may serve as a guide. In practical calculations it is convenient to divide the work into certain typical groups, e.g. facilities for ''bulk'', ''medium'', ''thin'', and ''multi-purpose'', but food products may come under any of these headings. Costs of irradiation depend on product properties, type of plant, annual and monthly quantities, doses, control standards, special requirements for re-packing or other additional handling, etc. Definite figures for a particular case must be based on an exact calculation, but for a preliminary judgement many general price-range indications are available to the industrialist, and for a variety of purposes it is already evident that irradiation processing is economically sound. Apart from plant economy it is advisable for the industrialist to study some general commercial problems also, such as consumer preference and marketing structure, for the commodity in question. This can often best be done by marketing a pilot production of some quantity, before final decisions are taken regarding major investments in highly-specialized equipment. For some products market testing has already been done with good results by existing research or production facilities, and indeed actual commercial marketing has been reported. In conclusion, many food irradiation processes seem to be promising from an economic point of view. (author)

  20. Food irradiation technology

    Trade in food and agricultural products is important to all countries, the economies of many developing countries would be significantly improved if they were able to export more food and agricultural products. Unfortunately, many products can not be traded because they are infested with, or hosts to, harmful pests, contaminated with microorganisms, or spoil quickly. Foods contaminated with microorganisms cause economic losses, widespread illness and death. Several technologies and products have been developed to resolve problems in trading food and to improve food safety, but none can provide all the solutions. Irradiation is an effective technology to resolve technical problems in trade of many food and agricultural products, either as a stand- alone technology or in combination with others. As a disinfestation treatment it allows different levels of quarantine security to be targeted and it is one of few methods to control internal pests. The ability of irradiation virtually to eliminate key pathogenic organisms from meat, poultry, and spices is an important public health advantage. In addition to controlling pests and eliminating harmful bacteria, irradiation also extends the storage life of many foods. In the laboratories of Turkish Atomic Energy Authority, many research projects were completed on the effects of gamma irradiation to the storage life of chicken meat, anchovy, Turkish fermented sausage, dried and fresh fruits and vegetables and also research projects were conducted on the effects of gamma irradiation on microorganisms (Salmonella, Campylo-bacteria, E.coli and S.aureus in white and red meat) and parasites (food-borne, trichostrongylus spp. and Nematodes spp.)

  1. Onion irradiation - a case study

    The irradiation of onions (Allium cepa L.) serves to prevent sprouting associated with long-term storage or transport and storage of onions in climatic conditions which stimulate sprouting. JECFI the Joint Expert Committee for Food Irradiation of FAO/IAEA/WHO, recommended the application of an irradiation dose of up to 150 Gy for sprout inhibition with onions. (author)

  2. Market trials of irradiated chicken

    The potential market for irradiated chicken breasts was investigated using a mail survey and a retail trial. Results from the mail survey suggested a significantly higher level of acceptability of irradiated chicken than did the retail trial. A subsequent market experiment involving actual purchases showed levels of acceptability similar to that of the mail survey when similar information about food irradiation was provided

  3. Contribution to the study of physico-chemical properties of surfaces modified by laser treatment. Application to the enhancement of localized corrosion resistance of stainless steels; Contribution a l'etude des proprietes physico-chimiques des surfaces modifiees par traitement laser. Application a l'amelioration de la resistance a la corrosion localisee des aciers inoxydables

    Pacquentin, W.

    2011-11-25

    integrite sur des periodes de plus en plus longues. L'objectif de ce travail de these est d'evaluer le potentiel d'un traitement de refusion laser pour ameliorer la resistance a la corrosion d'un acier inoxydable de type 304L; l'utilisation du laser dans le domaine des traitements de surface constituant un procede en pleine evolution a cause des changements recents dans la technologie des lasers. Dans le cadre de ce travail, le choix du laser s'est porte sur un laser nano-impulsionnel a fibre dopee ytterbium dont les caracteristiques permettent la fusion quasiinstantanee sur quelques microns de la surface traitee, immediatement suivie d'une solidification ultra-rapide avec des vitesses de refroidissement pouvant atteindre 1011 K/s. La combinaison de ces processus favorise l'elimination des defauts surfaciques, la formation de phases hors equilibre, la segregation d'elements chimiques et la formation d'une nouvelle couche d'oxyde dont les proprietes sont gouvernees par les parametres laser. Afin de les correler avec la reactivite electrochimique de la surface, l'influence de deux parametres laser sur les proprietes physicochimiques de la surface a ete etudiee: la puissance du laser et le taux de recouvrement des impacts laser. Pour clarifier ces relations, la resistance a la corrosion par piquration des surfaces traitees a ete determinee par des tests electrochimiques. Pour des parametres laser specifiques, le potentiel de piquration d'un acier inoxydable de type 304L augmente de plus de 500 mV traduisant ainsi une meilleure tenue a la corrosion localisee en milieu chlorure. L'interdependance des differents phenomenes resultant du traitement laser a rendu complexe la hierarchisation de leur effet sur la sensibilite de l'alliage teste. Cependant, il a ete montre que la nature de l'oxyde thermique forme au cours de la refusion laser et ses defauts sont du premier ordre pour l'amorcage des

  4. Post-irradiation effects in polyethylenes irradiated under various atmospheres

    If a large amount of polymer free radicals remain trapped after irradiation of polymers, the post-irradiation effects may result in a significant alteration of physical properties during long-term shelf storage and use. In the case of polyethylenes (PEs) some failures are attributed to the post-irradiation oxidative degradation initiated by the reaction of residual free radicals (mainly trapped in crystal phase) with oxygen. Oxidation products such as carbonyl groups act as deep traps and introduce changes in carrier mobility and significant deterioration in the PEs electrical insulating properties. The post-irradiation behaviour of three different PEs, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) was studied; previously, the post-irradiation behaviour of the PEs was investigated after the irradiation in air (Suljovrujic, 2010). In this paper, in order to investigate the influence of different irradiation media on the post-irradiation behaviour, the samples were irradiated in air and nitrogen gas, to an absorbed dose of 300 kGy. The annealing treatment of irradiated PEs, which can substantially reduce the concentration of free radicals, is used in this study, too. Dielectric relaxation behaviour is related to the difference in the initial structure of PEs (such as branching, crystallinity etc.), to the changes induced by irradiation in different media and to the post-irradiation changes induced by storage of the samples in air. Electron spin resonance (ESR), differential scanning calorimetry (DSC), infra-red (IR) spectroscopy and gel measurements were used to determine the changes in the free radical concentration, crystal fraction, oxidation and degree of network formation, respectively. - Highlights: • The post-irradiation behaviour of three different PEs, LDPE, LLDPE and HDPE, was studied. • In order to investigate influence of different irradiation media on post-irradiation behaviour, samples

  5. Storage of pork by irradiation

    In this paper the study of storage of pork, irradiated with Co-60 gamma rays, is recommended. The changes of the appearance and the main qualitative indexes of pork, irradiated with 1.5 M rad radiation and after two month's storage, were analysed. The evaluation of storage, transportation and nutritional acceptability of the two kinds of irradiated pork products was made. Systematic toxicological tests of rats and dogs, fed with irradiated pork, were given. The comparison of the economic facilitation of refrigerated pork and irradiated pork was made. (author)

  6. Safety aspects of irradiated foods

    The toxicological and microbiological safety of irradiated foods has been established after extensive research over a period of 30 years. No radioactivity can be induced in foods with the radioisotopes used to irradiate produce. The lethal effects of gamma irradiation on spoilage and pathogenic bacteria as well as insects and parasites, ensure a product of superior quality with regard to maintaining quality and hygiene. Feeding studies of unprecedented scope in the history of food research also proved the toxicological safety of irradiated foods. These findings are supported by recent short-term studies on toxicity and mutagenicity. The production and marketing of irradiated foods are therefore warranted and have indeed started worldwide

  7. Industrial application of food irradiation

    In the past three years the author has been irradiating foodstuffs with the Gammaster facility which was originally designed for the sterilization of medical equipment. A great diversity of products have been irradiated. In spite of some limitations of the facility, the process has proved to be very satisfactory. The technology for medical sterilization is directly applicable. At present, besides the sterilization of medical equipment, an average of twenty tonnes of foodstuffs, mainly spices, grains, herbs and fish products, are being irradiated every week. The Pilot Plant for Food Irradiation handles a similar quantity. The construction of the JS 7200, the JS 8500, and the JS 9000 irradiator is discussed. (Auth.)

  8. Commercial food irradiation in practice

    Dutch research showed great interest in the potential of food irradiation at an early stage. The positive research results and the potential applications for industry encouraged the Ministry of Agriculture and Fisheries to construct a Pilot Plant for Food Irradiation. In 1967 the Pilot Plant for Food Irradiation in Wageningen came into operation. The objectives of the plant were: research into applications of irradiation technology in the food industry and agricultural industry; testing irradiated products and test marketing; information transfer to the public. (author)

  9. Market Trials of Irradiated Spices

    Full text: The objectives of the experiment were to disseminate irradiated retail foods to the domestic publics and to test consumer acceptance on irradiated ground chilli and ground pepper. Market trials of irradiated ground chilli and ground pepper were carried out at 2 local markets and 4 in Bangkok and Nontaburi in 2005-2007. Before the start of the experiment, processing room, gamma irradiation room and labels of the products were approved by Food and Drug Administration, Thailand. 50 grams of irradiated products were packaged in plastic bags for the market trials. 688 and 738 bags of ground chilli and ground pepper were sold, respectively. Questionnaires distributed with the products were commented by 59 consumers and statistically analyzed by experimental data pass program. 88.1 and 91.4 percents of the consumers were satisfied with the quality and the price, respectively. 79.7% of the consumers chose to buy irradiated ground chilli and ground pepper because they believed that the quality of irradiated products were better than that of non-irradiated ones. 91.5% of the consumers would certainly buy irradiated chilli and pepper again. Through these market trials, it was found that all of the products were sold out and the majority of the consumers who returned the questionnaires was satisfied with the irradiated ground chilli and ground pepper and also had good attitude toward irradiated foods

  10. Biological Effects of Irradiated Fats

    Rats were fed with a diet containing 20% of irradiated oils. If the oils were irradiated with 2.5 Mrad, there was no indication of detrimental effects during the course of 80 weeks. Oils irradiated with 10 Mrad, however, caused an increase in lethality after a lag period of 9 to 12 months. Irradiation with 50 Mrad caused weight losses after 24 weeks, disturbed liver function, and hypoproteinaemia, with a relative increase in gamma globulins. No animal of this group exceeded a life-span of 75 weeks. Irradiation with 100 Mrad caused immediate toxic symptoms and a high lethality. There is no indication that peroxides are responsible for the toxicity of the irradiated oils. Because of the high content of dimeric products in the irradiated oils, it is assumed that dimerization of fatty acids is the cause of damage. (author)

  11. Vitamin A in irradiated foodstuffs

    Vitamin A losses induced by 10 MeV electrons in cream cheese, calf liver sausage, pig liver, whole egg powder and magarine continued to increase during storage for 4-8 weeks in presence of air. Thus, vitamin A loss in sausage irradiated with 5 Mrad was 22% on the day after irradiation, 61% after 4 weeks. Irradiation and storage at 00C instead of ambient temperature reduced these losses considerably. Exclusion of air (vacuum, nitrogen) or irradiation on dry ice (approx. -800C) were even more effective in preventing destruction of vitamin A. After 4 weeks of storage, cream cheese irradiated at 5 Mrad had lost 60% when irradiated and stored in air at ambient temperature, 20% in nitrogen atmosphere, 5% in vacuum package, and 5% when irradiated on dry ice and stored at ambient temperature. (orig.)

  12. Vitamin A in irradiated foodstuffs

    Vitamin A losses induced by 10 MeV electrons in cream cheese, calf liver sausage, pig liver, whole egg powder and margarine continued to increase during storage for 4-8 weeks in presence of air. Thus, vitamin A loss in sausage irradiated with 5 Mrad was 22% on the day after irradiation, 61% after 4 weeks. Irradiation and storage at 00C instead of at ambient temperature reduced these losses considerably. Exclusion of air (vacuum, nitrogen) or irradiation on dry ice (approx. -800C) were even more effective in preventing destruction of vitamin A. After 4 weeks of storage, cream cheese irradiated at 5 Mrad had lost 60% when irradiated and stored in air at ambient temperature, 20% in nitrogen atmosphere, 5% in vacuum package, and 5% when irradiated on dry ice and stored at ambient temperture. (orig.)

  13. Irradiated brown dwarfs

    Casewell, S L; Lawrie, K A; Maxted, P F L; Dobbie, P D; Napiwotzki, R

    2014-01-01

    We have observed the post common envelope binary WD0137-349 in the near infrared $J$, $H$ and $K$ bands and have determined that the photometry varies on the system period (116 min). The amplitude of the variability increases with increasing wavelength, indicating that the brown dwarf in the system is likely being irradiated by its 16500 K white dwarf companion. The effect of the (primarily) UV irradiation on the brown dwarf atmosphere is unknown, but it is possible that stratospheric hazes are formed. It is also possible that the brown dwarf (an L-T transition object) itself is variable due to patchy cloud cover. Both these scenarios are discussed, and suggestions for further study are made.

  14. Thermoluminescence of irradiated foods

    This report describes developments and applications of the thermoluminescence (TL) analysis of mineral contaminants in foods. Procedures are presented to obtain minerals from most different products such as pepper, mangos, shrimps and mussels. The effect of light exposure during the storage of foods on the TL intensity of minerals is examined and corresponding conclusions for routine control are drawn. It is also shown that the normalization of TL intensities - the essential step to identify irradiated samples - can not only be achieved by γ, X or β rays but also by UV radiation. The results allow the conclusion that a clear identification of any food which has been irradiated with more than 1 kGy is possible if enough minerals can be isolated. (orig.)

  15. Identification of irradiated seafood

    Interest in the use of ionising radiation for the treatment and preservation of food is increasing throughout the world. Foods are treated with ionising radiation to decrease microbial and insect infestations, inhibit maturation and extend shelf-life. Ionising radiation can be used in place of, or in conjunction with, chemical treatment and other processes currently used to preserve foods. The treatment of food by ionising radiation is accepted for specific purposes in several countries, although in other countries the sale of irradiated food for human consumption is prohibited. It would be advantageous if a method was available to determine whether a commercial food has been treated with ionising radiation and is within regulatory limitations for permissible food types and maximum allowable absorbed dose. Because of differences in the composition of the food commodities that potentially could be treated by irradiation, several analytical procedures will probably have to be developed. (author)

  16. Safety of irradiated foods

    Iwahara, Shigeo (Foods Medicines Safety Center (Japan)); Kobayashi, Kazuo

    1983-01-01

    The safety of 7 irradiated foods (potato, onion, rice, wheat, vienna sausage, fish paste and mandarine orange), in terms of 2-year long-term toxic effect, reproductive physiology and possible teratogenesis, was studied using 3 generations of rats, mice and monkeys. The genetic toxicity was studied by means of various mutagenicity tests. The details of the studies conducted by the authors to date and some overseas data were reported. The available data showed no toxic effect.

  17. Safety of irradiated foods

    The safety of 7 irradiated foods (potato, onion, rice, wheat, vienna sausage, fish paste and mandarine orange), in terms of 2-year long-term toxic effect, reproductive physiology and possible teratogenesis, was studied using 3 generations of rats, mice and monkeys. The genetic toxicity was studied by means of various mutagenicity tests. The details of the studies conducted by the authors to date and some overseas data were reported. The available data showed no toxic effect. (Chiba, N.)

  18. Analysis of irradiated materials

    Papers presented at the UKAEA Conference on Materials Analysis by Physical Techniques (1987) covered a wide range of techniques as applied to the analysis of irradiated materials. These varied from reactor component materials, materials associated with the Authority's radwaste disposal programme, fission products and products associated with the decommissioning of nuclear reactors. An invited paper giving a very comprehensive review of Laser Ablation Microprobe Mass Spectroscopy (LAMMS) was included in the programme. (author)

  19. Food Irradiation. Standing legislation

    The standing legislation in Mexico on food irradiation matter has its basis on the Constitutional Policy of the Mexican United States on the 4 Th. article by its refers to Secretary of Health, 27 Th. article to the Secretary of Energy and 123 Th. of the Secretary of Work and Social Security. The laws and regulations emanated of the proper Constitution establishing the general features which gives the normative frame to this activity. The general regulations of Radiological Safety expedited by the National Commission for Nuclear Safety and Safeguards to state the specifications which must be fulfill the industrial installations which utilizing ionizing radiations, between this line is founded, just as the requirements for the responsible of the radiological protection and the operation of these establishments. The project of Regulation of the General Health Law in matter of Sanitary Control of Benefits and Services, that in short time will be officialized, include a specific chapter on food irradiation which considers the International Organizations Recommendations and the pertaining harmonization stated for Latin America, which elaboration was in charge of specialized group where Mexico was participant. Additionally, the Secretary of Health has a Mexican Official Standard NOM-033-SSA1-1993 named 'Food irradiation; permissible doses in foods, raw materials and support additives' standing from the year 1995, where is established the associated requirements to the control registers, service constancies and dose limits for different groups of foods, moreover of the specific guidelines for its process. This standard will be adequate considering the updating Regulation of Benefits and Services and the limits established the Regulation for Latin America. The associated laws that cover in general terms it would be the requirements for food irradiation although such term is not manageable. (Author)

  20. Phytosanitary applications of irradiation

    Phytosanitary treatments are used to disinfest agricultural commodities of quarantine pests so that the commodities can be shipped out of quarantined areas. Ionizing irradiation is a promising phytosanitary treatment that is in- creasing in use worldwide. Almost 19000 metric tons of sweet potatoes and several fruits plus a small amount of curry leaf are irradiated each year in 6 countries, including the United States, to control a number of plant quarantine pests. Advantages over other treatments include tolerance by most fresh commodities, ability to treat in the final packaging and in pallet loads, and absence of pesticide residues. A regulatory disadvantage is lack of an independent verification of treatment efficacy because pests may be found alive during commodity inspection, although they will not complete development or reproduce. High-energy X-rays generated by electron beam are ideal for sterilizing large packages and pallet loads of food. The directional concentration and high penetration capability as well as excellent dose uniformity of X-rays allows disinfest efficiently. Application of irradiation phytosanitary in China still in its infancy. (authors)

  1. Genomic instability following irradiation

    Hacker-Klom, U.B.; Goehde, W. [Inst. fuer Strahlenbiologie, Muenster Univ. (Germany)

    2001-07-01

    Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)

  2. Genomic instability following irradiation

    Ionising irradiation may induce genomic instability. The broad spectrum of stress reactions in eukaryontic cells to irradiation complicates the discovery of cellular targets and pathways inducing genomic instability. Irradiation may initiate genomic instability by deletion of genes controlling stability, by induction of genes stimulating instability and/or by activating endogeneous cellular viruses. Alternatively or additionally it is discussed that the initiation of genomic instability may be a consequence of radiation or other agents independently of DNA damage implying non nuclear targets, e.g. signal cascades. As a further mechanism possibly involved our own results may suggest radiation-induced changes in chromatin structure. Once initiated the process of genomic instability probably is perpetuated by endogeneous processes necessary for proliferation. Genomic instability may be a cause or a consequence of the neoplastic phenotype. As a conclusion from the data available up to now a new interpretation of low level radiation effects for radiation protection and in radiotherapy appears useful. The detection of the molecular mechanisms of genomic instability will be important in this context and may contribute to a better understanding of phenomenons occurring at low doses <10 cSv which are not well understood up to now. (orig.)

  3. Control of food irradiation facilities and good irradiation practices

    Expansion of irradiation facilities employing commercial scale processes is evident in several countries. The list compiled by the Food Preservation Section of the Joint FAO/IAEA Division, Vienna (April 1988) showed that 34 counties have approved the use of irradiation process for more than 40 food commodities. In Asia and the Pacific Region, the main commercial application of irradiation process is still the sterilization of medical devices but applications to food processing are on the rise. To ensure the safety of irradiated foods, laws and regulations have to be promulgated to govern the facilities, the operations and the products. In most cases, there may be more than one governmental agency involved in regulatory control. The control activities include licensing/registration of a food irradiation premises as a food processing plant, registration of irradiated food in accordance with prescribed standards and regulating labelling practice as well as regularly conducting a comprehensive inspection of the facilities. The quality control programme must cover all aspects of treatment, handling, and distribution. It is emphasized that, as with all food technologies, effective quality control systems needs to be installed and adequately monitored at critical control points at the irradiation facility. Foods should be handled, stored, and transported according to GMP before, during, and after irradiation. Only foods meeting microbiological criteria and other quality standards should be accepted for irradiation. Besides, good irradiation practice (GIP) is also a fundamental principle of practice required specifically for food irradiation. With this recognition, the International Consultative Group on Food Irradiation (ICGFI) has elaborated a set of eight codes of GIP. The quality control system would also include proper packaging suitable for the product. Additional use of a logo to identify irradiated food should be permitted and may even become recognized as a symbol

  4. Estimation of irradiation temperature within the irradiation program Rheinsberg

    Stephan, I; Prokert, F; Scholz, A

    2003-01-01

    The temperature monitoring within the irradiation programme Rheinsberg II was performed by diamond powder monitors. The method bases on the effect of temperature on the irradiation-induced increase of the diamond lattice constant. The method is described by a Russian code. In order to determine the irradiation temperature, the lattice constant is measured by means of a X-ray diffractometer after irradiation and subsequent isochronic annealing. The kink of the linearized temperature-lattice constant curves provides a value for the irradiation temperature. It has to be corrected according to the local neutron flux. The results of the lattice constant measurements show strong scatter. Furthermore there is a systematic error. The results of temperature monitoring by diamond powder are not satisfying. The most probable value lays within 255 C and 265 C and is near the value estimated from the thermal condition of the irradiation experiments.

  5. Estimation of irradiation temperature within the irradiation program Rheinsberg

    The temperature monitoring within the irradiation programme Rheinsberg II was performed by diamond powder monitors. The method bases on the effect of temperature on the irradiation-induced increase of the diamond lattice constant. The method is described by a Russian code. In order to determine the irradiation temperature, the lattice constant is measured by means of a X-ray diffractometer after irradiation and subsequent isochronic annealing. The kink of the linearized temperature-lattice constant curves provides a value for the irradiation temperature. It has to be corrected according to the local neutron flux. The results of the lattice constant measurements show strong scatter. Furthermore there is a systematic error. The results of temperature monitoring by diamond powder are not satisfying. The most probable value lays within 255 C and 265 C and is near the value estimated from the thermal condition of the irradiation experiments. (orig.)

  6. Food irradiation - the retailer's view

    During October-November 1978 consignments of irradiated and non-irradiated strawberries were offered for sale in three branches of OK Bazaars. Samples were also subjected to simulated store conditions and the shelf life of both irradiated and non-irradiated packs determined. Irradiated packs were unaffected by decay until the 15th day of storage while the non-irradiated packs started to show signs of decay on the 7th day and were totally contaminated with fungus by the 14th day. In general, the response from the public was one of extreme interest and was to a large extent reflected in the encouraging sales. In March 1979, storage trials were carried out on green and ripe Keitt mangoes. The results of the trials show a marked increase in the shelf life of irradiated mangoes. The problems which exist with regard to the quality of fresh mangoes, namely anthracnose, soft brown rot and mango weevil, were all effectively controlled by irradiation. It must be realised that irradiation is no panacea and is not a substitute for other methods of food preservation. Any future marketing trials must be carried out using exclusively irradiated fruit. The customer must have the opportunity of 'seeing' the better fruit and not comparing it with other fruit which may be so near over-ripening on display that the price may have been reduced. The trials are to be continued on a much larger scale

  7. The wholesomeness of irradiated food

    It is apparent that there is a need for protection of the consumer and a need for governmental authorities to insure a safe and wholesome food supply for the population. Based on objective and scientific evidence regarding the safety of food irradiation, national and international health authorities are able to determine whether irradiated food is acceptable for human consumption. Following a thorough review of all available data, the Joint FAO/IAEA/WHO Expert Committee unconditionally approved wheat and ground wheat products and papaya irradiated for disingestation at a maximum dose of 100 krad, potatoes irradiated for sprout control at a maximum dose not exceeding 15 krad, and chicken irradiated at a maximum dose of 700 krad to reduce microbiological spoilage. Lastly, it unconditionally approved strawberries irradiated at a maximum dose of 300 krad to prolong storage. Onions at irradiated for sprout control at a maximum dose of 15 krad were temporarily approved, subject to preparation of further data on multigeneration reproduction studies on rats. Codfish and redfish eviscerated after irradiation at a maximum dose of 220 krad to reduce microbiological spoilage were also approved, based on the results of various studies in progress. Temporary, conditional approval of rice irradiated for insect disinfestation at a maximum dose of 100 krad was based on results of long-term studies on rats and monkies, available in the next review. Due to insufficient data, no decision regarding irradiated mushrooms was made. (Bell, E.)

  8. Consumer acceptance of irradiated foods

    Although the first experiments on food irradiation were carried out in 1916 in Sweden, food irradiation, is for consumers, a relatively new technology. From the sixties food irradiation has been applied more and more, so that the consumer movement has become alert to this technology. Since then a lot of controversies have arisen in the literature about wholesomeness, safety, effects, etc. Food irradiation is currently permitted on a small scale in about 30 countries; in some countries or states food irradiation has been put under a ban (e.g. Australia, New Zealand, New Jersey). The World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) have, however, chosen food irradiation as a safe and sound method for preserving and improving the safety of food. Reactions on the part of the consumer organizations of many countries are however not in favour of or are even opposed to food irradiation. In this chapter consumer acceptance related to technological developments is described, then the convergence of the consumer movement on public opinion and concern on food irradiation is discussed. The need for labelling of irradiated food products is discussed and finally recommendations are given of ways to change consumers attitudes to food irradiation. (author)

  9. Gemstone dedicated gamma irradiation development

    The gemstones gamma irradiation process to enhance the color is widely accepted for the jewelry industry. These gems are processed in conventional industrial gamma irradiation plant which are optimized for other purposes, using underwater irradiation devices with high rejection rate due to its poor dose uniformity. A new conception design, which states the working principles and manufacturing ways of the device, was developed in this work. The suggested device's design is based on the rotation of cylindrical baskets and their translation in circular paths inside and outside a cylindrical source rack as a planetary system. The device is meant to perform the irradiation in the bottom of the source storage pool, where the sources remain always shielded by the water layer. The irradiator matches the Category III IAEA classification. To verify the physical viability of the basic principle, tests with rotating cylindrical baskets were performed in the Multipurpose Irradiator constructed in the CTR, IPEN. Also, simulations using the CADGAMMA software, adapted to simulate underwater irradiations, were performed. With the definitive optimized irradiator, the irradiation quality will be enhanced with better dose control and the production costs will be significantly lower than market prices due to the intended treatment device's optimization. This work presents some optimization parameters and the expected performance of the irradiator. (author)

  10. Gemstone dedicated gamma irradiation development

    Omi, Nelson M.; Rela, Paulo R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)]. E-mails: nminoru@ipen.br; prela@ipen.br

    2007-07-01

    The gemstones gamma irradiation process to enhance the color is widely accepted for the jewelry industry. These gems are processed in conventional industrial gamma irradiation plant which are optimized for other purposes, using underwater irradiation devices with high rejection rate due to its poor dose uniformity. A new conception design, which states the working principles and manufacturing ways of the device, was developed in this work. The suggested device's design is based on the rotation of cylindrical baskets and their translation in circular paths inside and outside a cylindrical source rack as a planetary system. The device is meant to perform the irradiation in the bottom of the source storage pool, where the sources remain always shielded by the water layer. The irradiator matches the Category III IAEA classification. To verify the physical viability of the basic principle, tests with rotating cylindrical baskets were performed in the Multipurpose Irradiator constructed in the CTR, IPEN. Also, simulations using the CADGAMMA software, adapted to simulate underwater irradiations, were performed. With the definitive optimized irradiator, the irradiation quality will be enhanced with better dose control and the production costs will be significantly lower than market prices due to the intended treatment device's optimization. This work presents some optimization parameters and the expected performance of the irradiator. (author)

  11. Food Irradiation Development in Japan

    In Japan, the first food irradiation research was carried out on the preservation of fish and fishery products. In 1966, the Atomic Energy Commission of the Japanese Government (JAEC) decided to promote the National Project on Food Irradiation and, in 1967, the Steering Committee on food irradiation research in the Atomic Energy Bureau, Science and Technology-Agency, selected the following food items as of economic importance to the country, i.e., potatoes, onions, rice, wheat, ''Vienna'' sausage, ''kamaboko'' (fish meat jelly products) and mandarin oranges. The National Project is expected, to finish at the end of the 1981 fiscal year. Based on the studies by the National Project, irradiated potatoes were given ''unconditional acceptance'' for human consumption in 1972. Already in 1973, a commercial potato irradiator was built at Shihoro, Hokkaido. In 1980, the Steering Committee submitted a final report on the effectiveness and wholesomeness studies on irradiated onions to the JAEC. This paper gives a brief explanation of the legal aspects of food irradiation in Japan, and the present status of wholesomeness studies on the seven items of irradiated foods. In addition, topics concerning food irradiation research on ''kamaboko'', especially on the effectiveness and a new detecting method for the irradiation treatment of these products, are outlined. (author)

  12. Food irradiation development in Japan

    In Japan, the first food irradiation research was carried out on the preservation of fish and fishery products. In 1966, the Atomic Energy Commission of the Japanese Government (JAEC) decided to promote the National Project on Food Irradiation and, in 1967, the Steering Committee on food irradiation research in the Atomic Energy Bureau, Science and Technology Agency, selected the following food items as of economic importance to the country, i.e., potatoes, onions, rice, wheat, ''Vienna'' sausage, ''kamaboko'' (fish meat jelly products) and mandarin oranges. The National Project is expected to finish at the end of the 1981 fiscal year. Based on the studies by the National Project, irradiated potatoes were given ''unconditional acceptance'' for human consumption in 1972. Already in 1973, a commercial potato irradiator was built at Shihoro, Hokkaido. In 1980, the Steering Committee submitted a final report on the effectiveness and wholesomeness studies on irradiated onions to the JAEC. This paper gives a brief explanation of the legal aspects of food irradiation in Japan, and the present status of wholesomeness studies on the seven items of irradiated foods. In addition, topics concerning food irradiation research on ''kamaboko'', especially on the effectiveness and a new detecting method for the irradiation treatment of these products, are outlined. (author)

  13. Facts about food irradiation: Microbiological safety of irradiated food

    This fact sheet considers the microbiological safety of irradiated food, with especial reference to Clostridium botulinum. Irradiated food, as food treated by any ''sub-sterilizing'' process, must be handled, packaged and stored following good manufacturing practices to prevent growth and toxin production of C. botulinum. Food irradiation does not lead to increased microbiological hazards, nor can it be used to save already spoiled foods. 4 refs

  14. General description of irradiation and post irradiation examination in JMTR

    The JMTR (Japan Materials Testing Reactor) was designed to provide suitable facilities for conducting nuclear irradiation experiments necessary for the research and development of power reactor in Japan. The JMTR consists of a 50 MW high flux reactor, irradiation facilities and a multi-cell hot laboratory. The available irradiation facilities are various kinds of capsules, hydraulic rabbit facilities, high temperature and high pressure water loop, and high temperature and high pressure gas loop. The aim of this publication is a representation of the information concerned with the irradiation facilities. (author)

  15. Irradiation probe and laboratory for irradiated material evaluation

    The survey and assessment are given of the tasks carried out in the years 1971 to 1975 within the development of methods for structural materials irradiation and of a probe for the irradiation thereof in the A-1 reactor. The programme and implementation of laboratory tests of the irradiation probe are described. In the actual reactor irradiation, the pulse tube length between the pressure governor and the irradiation probe is approximately 20 m, the diameter is 2.2 mm. Temperature reaches 800 degC while the pressure control system operates at 20 degC. The laboratory tests (carried out at 20 degC) showed that the response time of the pressure control system to a stepwise pressure change in the irradiation probe from 0 to 22 at. is 0.5 s. Pressure changes were also studied in the irradiation probe and in the entire system resulting from temperature changes in the irradiation probe. Temperature distribution in the body of the irradiation probe heating furnace was determined. (B.S.)

  16. Market testing of irradiated food

    Viet Nam has emerged as one of the three top producers and exporters of rice in the world. Tropical climate and poor infrastructure of preservation and storage lead to huge losses of food grains, onions, dried fish and fishery products. Based on demonstration irradiation facility pilot scale studies and marketing of irradiated rice, onions, mushrooms and litchi were successfully undertaken in Viet Nam during 1992-1998. Irradiation technology is being used commercially in Viet Nam since 1991 for insect control of imported tobacco and mould control of national traditional medicinal herbs by both government and private sectors. About 30 tons of tobacco and 25 tons of herbs are irradiated annually. Hanoi Irradiation Centre has been continuing open house practices for visitors from school, universities and various different organizations and thus contributed in improved public education. Consumers were found to prefer irradiated rice, onions, litchi and mushrooms over those nonirradiated. (author)

  17. Food irradiation scenario in India

    Over 3 decades of research and developmental effort in India have established the commercial potential for food irradiation to reduce post-harvest losses and to ensure food safety. Current regulations permit irradiation of onions, potatoes and spices for domestic consumption and operation of commercial irradiators for treatment of food. In May 1997 draft rules have been notified permitting irradiation of several additional food items including rice, wheat products, dry fruits, mango, meat and poultry. Consumers and food industry have shown a positive attitude to irradiated foods. A prototype commercial irradiator for spices set up by Board of Radiation and Isotope Technology (BRIT) is scheduled to commence operation in early 1998. A commercial demonstration plant for treatment of onions is expected to be operational in the next 2 years in Lasalgaon, Nashik district. (author)

  18. Gamma irradiation service in Mexico

    In 1980 it was installed in Mexico, on the National Institute of Nuclear Research, an irradiator model J S-6500 of a canadian manufacture. Actually, this is the greatest plant in the Mexican Republic that offers a gamma irradiation process at commercial level to diverse industries. However, seeing that the demand for sterilize those products were not so much as the irradiation capacity it was opted by the incursion in other types of products. During 17 years had been irradiated a great variety of products grouped of the following form: dehydrated foods, disposable products for medical use, cosmetics, medicaments, various. Nowadays the capacity of the irradiator is saturated virtue of it is operated the 24 hours during the 365 days of the year and only its operation is suspended by the preventive and corrective maintenance. However, the fresh food market does not be attended since this irradiator was designed for doses greater than 10 kGy (1.0 Mrad)

  19. Irradiation of fruit and vegetables

    There is likely to be less economic incentive to irradiate fruits and vegetables compared with applications which increase the safety of foods such as elimination of Salmonella or decontamination of food ingredients. Of the fruit and vegetable applications, irradiation of mushrooms may offer the clearest economic benefits in North-Western Europe. The least likely application appears to be sprout inhibition in potatoes and onions, because of the greater efficiency and flexibility of chemical sprout inhibitors. In the longer-term, combinations between irradiation/MAP/other technologies will probably be important. Research in this area is at an early stage. Consumer attitudes to food irradiation remain uncertain. This will be a crucial factor in the commercial application of the technology and in the determining the balance between utilisation of irradiation and of technologies which compete with irradiation. (author)

  20. CEFR Irradiation Test and Application

    China Experimental Fast Reactor (CEFR) has completed physics start-up tests in 2010 and connected the grid on 40%FP in 2011. During start-up tests, the special irradiation test subassembly has been developed for measurement of distribution of reaction rate, spectrum index and neutron spectrum by using activation method in lower power. Characteristic of neutron field for irradiation in CEFR has been researched by calculation and experiments. In future, CEFR will been operated as an irradiation test facility for fuel, material and other application, and some irradiation projects, such as irradiation of cladding material, MOX fuel and (U, Np)O2 pellet have been planned. Now some irradiation rigs have been developed. (author)

  1. Status of irradiation capsule design

    For the irradiation test after the restart of JMTR, further precise temperature control and temperature prediction are required. In the design of irradiation capsule, particularly sophisticated irradiation temperature prediction and evaluation are urged. Under such circumstance, among the conventional design techniques of irradiation capsule, the authors reviewed the evaluation method of irradiation temperature. In addition, for the improvement of use convenience, this study examined and improved FINAS/STAR code in order to adopt the new calculation code that enables a variety of analyses. In addition, the study on the common use of the components for radiation capsule enabled the shortening of design period. After the restart, the authors will apply this improved calculation code to the design of irradiation capsule. (A.O.)

  2. Food irradiation: chemistry and applications

    Food irradiation is one of the most extensively and thoroughly studied methods of food preservation. Despite voluminous data on safety and wholesomeness of irradiated foods, food irradiation is still a “process in waiting.” Although some countries are allowing the use of irradiation technology on certain foods, its full potential is not recognized. Only 37 countries worldwide permit the use of this technology. If used to its full potential, food irradiation can save millions of human lives being lost annually due to food‐borne diseases or starvation and can add billions of dollars to the world economy. This paper briefly reviews the history and chemistry of food irradiation along with its main applications, impediments to its adoption, and its role in improving food availability and health situation, particularly in developing countries of the world

  3. Gamma irradiation of fruits

    At a Joint FAO/IAEA/WHO Expert Committee on Food Irradiation (JECFI) meeting held in 1976, recommendations were made to rationalize the unnecessarily elaborate wholesomeness evaluation procedures for irradiated foodstuffs. Irradiation at the commercially recommended doses did not adversely affect the constituents of mangoes, papayas, litchis and strawberries at the edible-ripe stage. These favourable radiation-chemical results justified the development of a theoretical model mango which could be used for extrapolation of wholesomeness data from an individual fruit species to all others within the same diet class. Several mathematical models of varying orders of sophistication were evolved. In all of them, it was assumed that the radiant energy entering the system reacted solely with water. The extent of the reaction of the other components of the model fruit with the primary water radicals was then determined. No matter which mathematical treatment was employed, it was concluded that the only components which would undergo significant modification would be the sugars. In order to extrapolate these data from the mango to other fruits, mathematical models of three fruits containing less sugar than the mango, viz. the strawberry, tomato and lemon, were compiled. With these models, the conclusion was reached that the theoretical degradation spectra of these fruits were qualitatively similar to the degradation pattern of the model mango. Theory was again substantiated by the practical demonstration of the protective effect of the sugars in the tomato and lemon. The decrease in radiation damage was enhanced by the mutual protection of the components of the whole synthetic fruits with ultimate protection being afforded by the biological systems of the real fruits

  4. Detection of irradiated chestnuts

    Full text: Ionizing radiation treatment of food is growing acceptance and application to ever increasing variety of products. The method has indeed proved efficient in reducing food losses and in improving safety of products. Among vegetable products of interest for radiation treatment, chestnuts have recently been considered. Irradiation treatment of chestnuts has been authorized in countries such as Korea as a valid and safe alternative to the widespread use of fumigants. At the Italian level, Montella chestnut is a typical variety recognized as a PGI (Protected Geographical Indication) product and widely used in confectionery industry. In view of an extension of radiation treatment to this kind of product, to permit legal controls and meet consumer consensus, reliable methods for detecting irradiated chestnuts have to be proposed and validated. The task of finding detection methods for irradiated chestnuts can be in principle afforded with different methods. The cellulose and sugar contained in the skin and pulp, respectively, might suggest the use of the protocol EN 1787 and EN 13708, relative to ESR spectroscopy. In particular, the protocol EN 1787, based on ESR technique, is applied to detect cellulose radicals radio-induced in outer shell part of the sample as well as in the seed present in the inner part of the fruit. It is known that ionizing radiation may induce two different ESR signals: cellulose signal and a single line signal centered at g = 2. The protocol EN 1787 uses the low intensity cellulose signal for identification. In the present study, in case of low cellulose content, even the g = 2 is analyzed for setting up an alternative identification procedure. Protocol EN 13708, used to identify food containing crystalline sugar by ESR spectroscopy, is applied to the pulp of fruit. As for luminescence measurements, mineral isolation of silicates and TL measurements is done according to European Standard EN 1788. Preliminary test showed that the

  5. Craniospinal irradiation techniques

    Scarlatescu, Ioana, E-mail: scarlatescuioana@gmail.com; Avram, Calin N. [Faculty of Physics, West University of Timisoara, Bd. V. Parvan 4, 300223 Timisoara (Romania); Virag, Vasile [County Hospital “Gavril Curteanu” - Oradea (Romania)

    2015-12-07

    In this paper we present one treatment plan for irradiation cases which involve a complex technique with multiple beams, using the 3D conformational technique. As the main purpose of radiotherapy is to administrate a precise dose into the tumor volume and protect as much as possible all the healthy tissues around it, for a case diagnosed with a primitive neuro ectoderm tumor, we have developed a new treatment plan, by controlling one of the two adjacent fields used at spinal field, in a way that avoids the fields superposition. Therefore, the risk of overdose is reduced by eliminating the field divergence.

  6. Development of blood irradiators

    Over a period of several years, a small, fully portable blood irradiator has been developed for ultimate use in suppressing early rejection of organ transplants in humans. It could also be useful for other medical problems, e.g., treating some forms of leukemia or arthritis. The units have been successfully evaluated in several animal species, resulting in sharply reduced lymphocyte levels and prolonged skin-graft retention. Work during the past year was directed toward development of hardware in anticipation of kidney transplant studies, to be performed in dogs in FY 1982, and identifying whether dose fractionation significantly changed lymphocyte response

  7. Neoplasms in irradiated populations

    The paper describes the results of three prospective studies which have been ongoing for 25 years. The study populations include: (1) persons treated with x rays in infancy for alleged enlargement of the thymus gland; (2) persons treated in childhood with x rays and/or radium for lymphoid hyperplasia of the nasopharynx; and (3) women treated with x rays for acute postpartum mastitis. The studies have resulted in the quantification of risk for radiogenic thyroid and breast cancer for periods up to 40 years post irradiation

  8. Microvascular anastomes in irradiated vessels

    The aim of the study was to investigate the healing of microvascular anastomoses in rat common femoral arteries and veins eight to nine months after the vessels had received irradiation. Patency rates in non irradiated arteries and veins were 92% and 100% respectively. The rate in irradiated arteries and veins (all groups together) was 96% and 69% respectively. The venous patency rate in the 5000, 7000 and 9000 rads groups taken together (13 rats) fell to 55%. (Auth.)

  9. Irradiation stability of welded joints

    Results are presented of investigations into the neutron irradiation stability of welded joints in two types of steel used for reactor pressure vessels. Details are given of the materials used, method of welding and tests applied. The effect of irradiation on the notch toughness transition curve is shown. The results of the studies into irradiation embrittlement of all the welded joints and parent materials of the steels for the pressure vessels are summarized. (U.K.)

  10. National symposium on food irradiation

    This report contains abstracts of papers delivered at the National symposium on food irradiation held in Pretoria. The abstracts have been grouped into the following sections: General background, meat, agricultural products, marketing and radiation facilities - cost and plant design. Each abstract has been submutted separately to INIS. Tables listing irradiated food products cleared for human consumption in different countries are given as well as a table listing those irradiated food items that have been cleared in South Africa

  11. Food irradiation facilities at Trombay

    The process parameters for radiation preservation of foods including grain, fruits, vegetables and seafoods are being evaluated with the experimental cobalt-60 and caesium-137 irradiators. The design features of three irradiators that are being used were considered mainly on the basis of obtaining variable throughputs and variable dose rates, making these facilities flexible for operation for a variety of purposes and the products. The paper highlights certain aspects of these irradiators, modifications carried out, dosimetry and maintenance requirements. (auth.)

  12. Desinfestation of soybeans by irradiation

    The effect of irradiation with the doses 0.5 and 1.0 kGy on desinfestation of soy beans and on important chemical compounds of this product was studied in this paper. The results showed the effectiveness of applied doses in the control of insect pests of soy beans during its storage and total proteins, fat and moisture and also the identity and quality characteristics of oil extrated from irradiated product which were not change by irradiation

  13. JRR-4 medical irradiation facility

    Torii, Y.; Yamamoto, K.; Hori, N.; Kumada, H.; Horiguchi, Y. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-11-01

    JAERI started Boron Neutron Capture Therapy (BNCT) at JRR-2 in 1990. JRR-2 was performed 33 BNCT until 1996 when JRR-2 operation was terminated for decommissioning the reactor. JRR-4 was constructed to research the reactor shielding of the first Japanese nuclear ship ''Mutsu'' in 1965. JRR-4 was modified for reducing fuel enrichment and constructing a new medical irradiation facility at 1997 when after the terminating operation of JRR-2. The medical irradiation facility is especially using for BNCT of brain cancer. JRR-4 medical irradiation facility was designed for both using of thermal neutron beam and epi-thermal neutron. Thermal neutron is using for conventional Japanese BNCT as inter operative irradiation therapy. Epi-thermal neutron beam will be using advanced BNCT for deep cancer and without craniotomy operation for irradiation at the facility. The first medical irradiation for BNCT of JRR-4 was carried out on October 25, 1999. Since then, seven times of irradiation was performed by the end of June 2000. In BNCT irradiation, boron concentration and thermal flux measurements were performed by JAERI. Boron concentration of patient brood was measured using prompt gamma ray analysis technique. Thermal neutron flux was measured by gold wire activation method using beta - gamma coincidence counting system. There data were furnished to medical doctor for determination the irradiation time of BNCT. (author)

  14. Hepatopathy following irradiation and adriamycin

    This report describes two cases of hepatopathy following irradiation and adriamycin at doses and volumes of irradiation ordinarily considered within the tolerance of hepatic function. In one case, fatal hepatopathy followed 2400 rad/17 fractions/28 days to the entire liver with preceding and concurrent adriamycin. In the second case moderate clinical changes occurred after treatment in which much of the right lobe of the liver was shielded following 2500 rad/23 fractions/32 days with adriamycin administered before, during, and after irradiation. The locally enhancing effects of adriamycin on hepatic tolerance to irradiation are discussed

  15. Societal benefits of food irradiation

    Food irradiation has a direct impact on society by reducing the occurrence of food-borne illness, decreasing food spoilage and waste, and facilitating global trade. Food irradiation is approved in 40 countries around the world to decontaminate food of disease and spoilage causing microorganisms, sterilize insect pests, and inhibit sprouting. A recent estimate suggests that 500,000 metric of food is currently irradiated worldwide, primarily to decontaminate spices. Since its first use in the 1960s the use of irradiation for food has grown slowly, but it remains the major technology of choice for certain applications. The largest growth sector in recent years has been phytosanitary irradiation of fruit to disinfest fruit intended for international shipment. For many countries which have established strict quarantine standards, irradiation offers as an effective alternative to chemical fumigants some of which are being phased out due to their effects on the ozone layer. Insects can be sterilized at very low dose levels, thus quality of fruit can be maintained. Irradiation is also highly effective in destroying microbial pathogens such as Salmonella spp., E. coli, and Listeria, hence its application for treatment of spices, herbs, dried vegetables, frozen seafood, poultry, and meat and its contribution to reducing foodborne illnesses. Unfortunately the use of irradiation for improving food safety has been under-exploited. This presentation will provide details on the use, benefits, opportunities, and challenges of food irradiation. (author)

  16. International Developments of Food Irradiation

    Loaharanu, P. [Head, Food Preservation Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstr. 5, A-1400, Vienna (Austria)

    1997-12-31

    Food irradiation is increasingly accepted and applied in many countries in the past decade. Through its use, food losses and food-borne diseases can be reduced significantly, and wider trade in many food items can be facilitated. The past five decades have witnessed a positive evolution on food irradiation according to the following: 1940`s: discovery of principles of food irradiation; 1950`s: initiation of research in advanced countries; 1960`s: research and development were intensified in some advanced and developing countries; 1970`s: proof of wholesomeness of irradiated foods; 1980`s: establishment of national regulations; 1990`s: commercialization and international trade. (Author)

  17. International Developments of Food Irradiation

    Food irradiation is increasingly accepted and applied in many countries in the past decade. Through its use, food losses and food-borne diseases can be reduced significantly, and wider trade in many food items can be facilitated. The past five decades have witnessed a positive evolution on food irradiation according to the following: 1940's: discovery of principles of food irradiation; 1950's: initiation of research in advanced countries; 1960's: research and development were intensified in some advanced and developing countries; 1970's: proof of wholesomeness of irradiated foods; 1980's: establishment of national regulations; 1990's: commercialization and international trade. (Author)

  18. Generic phytosanitary irradiation treatments

    The history of the development of generic phytosanitary irradiation (PI) treatments is discussed beginning with its initial proposal in 1986. Generic PI treatments in use today are 150 Gy for all hosts of Tephritidae, 250 Gy for all arthropods on mango and papaya shipped from Australia to New Zealand, 300 Gy for all arthropods on mango shipped from Australia to Malaysia, 350 Gy for all arthropods on lychee shipped from Australia to New Zealand and 400 Gy for all hosts of insects other than pupae and adult Lepidoptera shipped to the United States. Efforts to develop additional generic PI treatments and reduce the dose for the 400 Gy treatment are ongoing with a broad based 5-year, 12-nation cooperative research project coordinated by the joint Food and Agricultural Organization/International Atomic Energy Agency Program on Nuclear Techniques in Food and Agriculture. Key groups identified for further development of generic PI treatments are Lepidoptera (eggs and larvae), mealybugs and scale insects. A dose of 250 Gy may suffice for these three groups plus others, such as thrips, weevils and whiteflies. - Highlights: ► The history of phytosanitary irradiation (PI) treatments is given. ► Generic PI treatments in use today are discussed. ► Suggestions for future research are presented. ► A dose of 250 Gy for most insects may suffice.

  19. Food irradiation and sterilization

    Josephson, Edward S.

    Radiation sterilization of food (radappertization) requires exposing food in sealed containers to ionizing radiation at absorbed doses high enough (25-70 kGy) to kill all organisms of food spoilage and public health significance. Radappertization is analogous to thermal canning is achieving shelf stability (long term storage without refrigeration). Except for dry products in which autolysis is negligible, the radappertization process also requires that the food be heated to an internal temperature of 70-80°C (bacon to 53°C) to inactivate autolytic enzymes which catalyze spoilage during storage without refrigeration. To minimize the occurence of irradiation induced off-flavors and odors, undesirable color changes, and textural and nutritional losses from exposure to the high doses required for radappertization, the foods are vacuum sealed and irradiated frozen (-40°C to -20°C). Radappertozed foods have the characteristic of fresh foods prepared for eating. Radappertization can substitute in whole or in part for some chemical food additives such as ethylene oxide and nitrites which are either toxic, carcinogenic, mutagenic, or teratogenic. After 27 years of testing for "wholesomeness" (safety for consumption) of radappertized foods, no confirmed evidence has been obtained of any adverse effecys of radappertization on the "wholesomeness" characteristics of these foods.

  20. Food irradiation and sterilization

    Radiation sterilization of food (radappertization) requires exposing food in sealed containers to ionizing radiation at absorbed doses high enough (25 to 70 kGy) to kill all organisms of food spoilage and public health significance. Radappertization is analogous to thermal canning in achieving shelf stability (long term storage without refrigeration). Except for dry products in which autolysis is negligible, the radappertization process also requires that the food be heated to an internal temperature of 70 to 800C (bacon to 530C) to inactivate autolytic enzymes which catalyze spoilage during storage without refrigeration. To minimize the occurrence of irradiation induced off-flavors and odors, undesirable color changes, and textural and nutritional losses from exposure to the high doses required for radappertization, the foods are vacuum sealed and irradiated frozen (-400C to -200C). Radappertized foods have the characteristic of fresh foods prepared for eating. Radappertization can substitute in whole or in part for some chemical food additives such as ethylene oxide and nitrites which are either toxic, carcinogenic, mutagenic, or teratogenic. After 27 years of testing for 'wholesomeness' (safety for consumption) of radappertized foods, no confirmed evidence has been obtained of any adverse effects of radappertization on the 'wholesomeness' characteristics of these foods. (author)

  1. Irradiation of food

    Processing of food with ionizing radiation is a method suitable to enhance shelf-life and hygienic quality. Up to a dose of 10 kGy the method is considered wholesome. In many countries the practical use of food irradiation is increasing, however, in the Federal Republic of Germany the process is strictly forbidden. Applications and methods for radiation processing of food are compiled, limits and prospects are explained, and advantages and disadvantages are compared with traditional methods. Identification of irradiated foods and dosimetry and process control for radiation processing of food are areas where further research is needed. Continuous processing of particulate foods in bulk is an application where electron accelerators might be profitable. Beam parameters and velocity distribution of food particles in the treatment area can be matched for an effective result. Thus, dose distribution can be adjusted for homogeneous treatment and at the same time radiation energy is absorbed almost completely. An example of an experimental plant for radiation processing of grain and spices is shown. Decontamination of spices by radiation processing is an alternative to chemical fumigation, which now is widely forbidden. (orig.)

  2. Facts about food irradiation: Irradiation and food safety

    This fact sheet focusses on the question of whether irradiation can be used to make spoiled food good. No food processing procedures can substitute for good hygienic practices, and good manufacturing practices must be followed in the preparation of food whether or not the food is intended for further processing by irradiation or any other means. 3 refs

  3. Facts about food irradiation: Packaging of irradiated foods

    This fact sheet considers the effects on packaging materials of food irradiation. Extensive research has shown that almost all commonly used food packaging materials toted are suitable for use. Furthermore, many packaging materials are themselves routinely sterilized by irradiation before being used. 2 refs

  4. Storage tests with irradiated and non-irradiated onions

    The results of several test series on the storage of irradiated and non-irradiated German grown onion are reported. Investigated was the influence of the irradiation conditions such as time and dose and of the storage conditions on sprouting, spoilage, browning of the vegetation centres, composition of the onions, strength and sensorial properties of seven different onion varieties. If the onions were irradiated during the dormancy period following harvest, a dose of 50 Gy (krad) was sufficient to prevent sprouting. Regarding the irradiated onions, it was not possible by variation of the storage conditions within the limits set by practical requirements to extend the dormancy period or to prevent browning of the vegetation centres, however. (orig.) 891 MG 892 RSW

  5. Consumer acceptance of irradiated poultry

    A simulated supermarket setting (SSS) test was conducted to determine whether consumers (n = 126) would purchase irradiated poultry products, and the effects of marketing strategies on consumer purchase of irradiated poultry products. Consumer preference for irradiated poultry was likewise determined using a home-use test. A slide program was the most effective educational strategy in changing consumers' purchase behavior. The number of participants who purchased irradiated boneless, skinless breasts and irradiated thighs after the educational program increased significantly from 59.5 and 61.9% to 83.3 and 85.7% for the breasts and thighs, respectively. Using a label or poster did not increase the number of participants who bought irradiated poultry products. About 84% of the participants consider it either 'somewhat necessary' or 'very necessary' to irradiate raw chicken and would like all chicken that was served in restaurants or fast food places to be irradiated. Fifty-eight percent of the participants would always buy irradiated chicken if available, and an additional 27% would buy it sometimes. About 44% of the participants were willing to pay the same price for irradiated chicken as for nonirradiated. About 42% of participants were willing to pay 5% or more than what they were currently paying for nonirradiated chicken. Seventy-three percent or more of consumers who participated in the home-use test (n = 74) gave the color, appearance, and aroma of the raw poultry products a minimum rating of 7 (= like moderately). After consumers participated in a home-use test, 84 and 88% selected irradiated thighs and breasts, respectively, over nonirradiated in a second SSS test

  6. Consumer acceptance of irradiated poultry.

    Hashim, I B; Resurreccion, A V; McWatters, K H

    1995-08-01

    A simulated supermarket setting (SSS) test was conducted to determine whether consumers (n = 126) would purchase irradiated poultry products, and the effects of marketing strategies on consumer purchase of irradiated poultry products. Consumer preference for irradiated poultry was likewise determined using a home-use test. A slide program was the most effective educational strategy in changing consumers' purchase behavior. The number of participants who purchased irradiated boneless, skinless breasts and irradiated thighs after the educational program increased significantly from 59.5 and 61.9% to 83.3 and 85.7% for the breasts and thighs, respectively. Using a label or poster did not increase the number of participants who bought irradiated poultry products. About 84% of the participants consider it either "somewhat necessary" or "very necessary" to irradiate raw chicken and would like all chicken that was served in restaurants or fast food places to be irradiated. Fifty-eight percent of the participants would always buy irradiated chicken if available, and an additional 27% would buy it sometimes. About 44% of the participants were willing to pay the same price for irradiated chicken as for nonirradiated. About 42% of participants were willing to pay 5% or more than what they were currently paying for nonirradiated chicken. Seventy-three percent or more of consumers who participated in the home-use test (n = 74) gave the color, appearance, and aroma of the raw poultry products a minimum rating of 7 (= like moderately). After consumers participated in a home-use test, 84 and 88% selected irradiated thighs and breasts, respectively, over nonirradiated in a second SSS test. PMID:7479506

  7. Food irradiation development: Malaysian perspective

    Malaysia recognised the potential of food irradiation as a technology that can contribute to solving some preservation problems associated with local agricultural produce. Research studies in this technology were initiated in late 1970s and since 1985, all activities pertaining to R and D applications, adoption and technology transfer of food irradiation were coordinated by The National Working Committee on Food Irradiation which comprises of members from research institutes, universities, regulatory agencies and consumer association. To date, technical feasibility studies conducted on 7 food items / agricultural commodities of economic importance demonstrated the efficacy of irradiation in extending shelf-life, improving hygienic quality and overcoming quarantine barriers in trade. Presently, 1 multipurpose Co-60 irradiator (I MCi), 2 gammacells and an electron beam machine (3 MeV) are available at MINT for research and commercial runs. The Malaysian Standards on Guidelines for Irradiation of Food was formulated in 1992 to facilitate application by local food industries. However, Malaysia has not yet commercially adopt the technology. Among many factors contributing to the situation is the apparent lack of interest by food industries and consumers. Consumer attitude study indicated majority of consumers are still unaware of the benefits of the technology and expressed concern for the safety of process and irradiated products due to limited knowledge and adverse publicity by established consumer groups. Although the food processors indicate positive attitude towards food irradiation, there remain many factors delaying its commercial application such as limited knowledge, cost-benefit, logistics and consumer acceptance. On the regulatory aspect, approval is required from the Director-General of Ministry of Health prior to application of irradiation on food and sale of irradiated food but efforts are being geared towards approving irradiation of certain food

  8. Detection methods of irradiated foodstuffs

    Full text: Food irradiation has, in certain circumstances, an important role to play both in promoting food safety and in reducing food losses. The safety and availability of nutritious food are essential components of primary health care. WHO actively encourages the proper use of food irradiation in the fight against foodborne diseases and food losses. To this end, it collaborates closely with FAO and IAEA. Food irradiation can have a number of beneficial effects, including delay of ripening and prevention of sprouting; control of insects, parasites, helminths, pathogenic and spoilage bacteria, moulds and yeasts; and sterilization, which enables commodities to be stored unrefrigerated for long periods. The 1990s witnessed a significant advancement in food irradiation processing. As a result, progress has been made in commercialization of the technology, culminating in greater international trade in irradiated foods and the implementation of differing regulations relating to its use in many countries. Codex General Standard for Irradiated Foodstuffs and Recommended International Code of Practice for the Operation of Irradiation Facilities Used for the Treatment of Foods regulate food irradiation at international level. At European Union level there are in power Directive 1999/2/EC and Directive1999/3/EC. Every particular country has also its own regulations regarding food irradiation. In Romania, since 2002 the Norms Regarding Foodstuffs and Food Ingredients Treated by Ionizing Radiation are in power. These Norms are in fact the Romanian equivalent law of the European Directives 1999/2/EC and 1999/3/EC. The greater international trade in irradiated foods has led to the demand by consumers that irradiated food should be clearly labeled as such and that methods capable of differentiating between irradiated and nonirradiated products should be available. Thus a practical basis was sought to allow consumers to exercise a free choice as to which food they purchase. If a

  9. National symposium on food irradiation

    This report contains proceedings of papers delivered at the national symposium on food irradiation held in Pretoria. The proceedings have been grouped into the following sections: general background; meat; agricultural products; marketing; and radiation facilities - cost and plant design. Each paper has been submitted separately to INIS. Tables listing irradiated food products cleared for human consumption in different countries are given

  10. Neutron irradiation effect of silicon

    Several kinds of silicon wafers were irradiated at four neutron fields with different energy spectra. Electrical resistivity and deep level defect concentrations after the neutron irradiation, and their changes against number of displacement atoms (DPA's) for different neutron fields were compared. The number of DPA's was calculated by N. Yamano's data. (author)

  11. Craniospinal irradiation using Rapid Arc

    Fandino, J. M.; Silva, M. C.; Marino, A.; Candal, A.; Diaz, I.; Fernandez, C.; Gesto, C.; Izquierdo, P.; Losada, C.; Poncet, M.; Soto, M.; Triana, G.

    2013-07-01

    Cranio-Spinal Irradiation is technically very challenging, historically field edge matching is needed because of the mechanical limitations of standard linear accelerators. The purpose of this study is to assess the Volumetric Arc Therapy as a competitive technique for Cranio-Spinal Irradiation compared to the conventional 3D Conformal Radiotherapy technique. (Author)

  12. The safety of irradiated foods

    This state of the art outline review written for 'Food Manufacture' looks at the wholesomeness of irradiated foods, and makes a comparison with conventionally treated products. Topics mentioned are doses, radioresistance of microorganisms especially clostudium botulinum and the problem of bacterial toxins, storage conditions, nutrition, especially vitamin loss, and detection of irradiation. (U.K.)

  13. Food irradiation: a Queensland perspective

    The National Farmers Federation is satisfied that all safety issues associated with food irradiation have been adequately addressed. It recommends that the Codex Alimentarius standard of 120 kilogray treatment be adopted in Australia. Economic arguments are advanced for the irradiation of horticultural products, fish, seafoods, red meat and chicken meat

  14. Consumer attitude toward food irradiation

    Consumer attitudes toward food irradiation were evaluated. The influence of educational efforts on consumer concern for the safety of irradiated products and willingness to buy irradiated foods were measured. Demographic and psychological factors were studied in relation to attitudes. An educational leaflet describing current scientific information regarding the safety, advantages, and disadvantages of food irradiation was developed and used in two studies evaluating attitude change. In the first study, attitude change among two groups of consumers with different philosophic orientations was measured. In a second study, the effectiveness of an educational leaflet received through the mail and a poster display were examined. In a third study response to food irradiation was related to value hierarchy, locus of control, innovativeness, and demographic parameters. Initially, subjects showed a higher concern for other areas of food safety, particularly the use of chemicals and sprays on food, than toward food irradiation. After educational efforts, conventional consumers expressed minor concern toward irradiation whereas ecologically sensitive alternative consumers obtained from a food cooperative expressed major concern. A knowledgeable discussion leader lowered irradiation concern among conventional consumers. In contrast, concern among alternative consumers did not diminish when given the opportunity to discuss safety issues with a knowledgeable person

  15. Nutritional aspects of irradiated shrimp

    Data available in the literature on the nutritional aspects of irradiated shrimp are reviewed and the indication is that irradiation of shrimp at doses up to about 3.2 kGy does not significantly affect the levels of its protein, fat, carbohydrate and ash. There are no reports on the effect of irradiation of shrimp above 3.2 kGy on these components. Limited information available indicates that there are some minor changes in the fatty acid composition of shrimp as a result of irradiation. Irradiation also causes some changes in the amino acid composition of shrimp; similar changes occur due to canning and hot-air drying. Some of the vitamins in shrimp, such as thiamine, are lost as a result of irradiation but the loss is less extensive than in thermally processed shrimp. Protein quality of shrimp, based on the growth of rats as well as that of Tetrahymena pyriformis, is not affected by irradiation. No adverse effects attributed to irradiation were found either in short-term or long-term animal feeding tests

  16. Food irradiation and bacterial toxins

    The authors' findings indicate that irradiation confers no advantage over heat processing in respect of bacterial toxins (clostridium botulinum, neurotoxin A and staphylococcal enterotoxin A). It follows that irradiation at doses less than the ACINF recommended upper limit of 10 kGy could not be used to improve the ambient temperature shelf life on non-acid foods. (author)

  17. Irradiation damage in lithium ceramics

    The irradiation response of two candidate tritium-breeding materials, LiAlO2 and Li2ZrO3, was investigated using electron irradiation to produce atomic displacements, and EPR and transmission electron microscopy (TEM) to detect damage responses. In a first set of experiments, single crystals and sintered polycrystals of γ-LiAlO2 were irradiated with 2.5 MeV electrons at a temperature of 20 K. EPR measurements made at 4 K on samples kept at 77 K after electron irradiation confirm that paramagnetic defects are created during irradiation, and that most of these defects disappear at about 100 K. TEM observations at room temperature indicate, however, that annealing of these defects does not result in visible defect aggregates. In a second set of experiments, sintered polycrystalline LiAlO2 and Li2ZrO3 samples were thinned to electron transparency and heavily irradiated in situ with 200 keV electrons. In LiAlO2, laths of LiAl5O8 grew intragranularly under irradiation. Li2ZrO3 showed little or no aggregate damage after extensive irradiation near room temperature. (orig.)

  18. Economic aspects of food irradiation

    Currently there is a movement towards commercial use of food irradiation. As with other commercial operations, the objective of commercial food irradiation is to process foods to obtain a particular beneficial effect and to market such foods to obtain a profit. Using economic analysis, business management evaluates benefits and risks in order to estimate the profitability of a contemplated venture employing food irradiation. If an economic analysis indicates that an adequate return on the required investment can be obtained, management has a proper basis on which to proceed with the venture. A procedure for obtaining an appropriate economic analysis for commercial use of food irradiation is considered herewith in detail. It covers the use of either a contract service, free standing type of irradiation facility or an integrated in-plant irradiator. The kinds of information needed for the economic analysis are indicated, including those for estimating capital and operating costs. It is emphasized that specific information relevant to the venture under consideration is required. Since commercial use of food irradiation requires that it be profitable, and since profitability is the incentive for a business to undertake it, a number of uses of food irradiation are identified and listed as those that have the potential for yielding cost-benefits. (author). 7 refs, 1 fig., 4 tabs

  19. Commercial implementation of food irradiation

    Welt, M. A.

    In July 1981, the first specifically designed multi-purpose irradiation facility for food irradiation was put into service by the Radiation Technology, Inc. subsidiary Process Technology, Inc. in West Memphis, Arkansas. The operational experience gained, resulted in an enhanced design which was put into commercial service in Haw River, North Carolina, by another subsidiary, Process Technology (N.C.), Inc. in October 1983. These facilities have enabled the food industry to assess the commercial viability of food irradiation. Further impetus towards commercialization of food irradiation was gained in March 1981 with the filing in the Federal Register, by the FDA, of an Advanced Proposed Notice of Rulemaking for Food Irradiation. Two years later in July 1983, the FDA approved the first food additive regulation involving food irradiation in nineteen years, when they approved the Radiation Technology, Inc. petition calling for the sanitization of spices, onion powder and garlic powder at a maximum dosage of 10 kGy. Since obtaining the spice irradiation approval, the FDA has accepted four additional petitions for filing in the Federal Register. One of the petitions which extended spice irradiation to include insect disinfestation has issued into a regulation while the remaining petitions covering the sanitization of herbs, spice blends, vegetable seasonings and dry powdery enzymes as well as the petition to irradiate hog carcasses and pork products for trichinae control at 1 kGy, are expected to issue either before the end of 1984 or early in 1985. More recently, food irradiation advocates in the United States received another vote of confidence by the announcement that a joint venture food irradiation facility to be constructed in Hawaii by Radiation Technology, is backed by a contractual committment for the processing of 40 million pounds of produce per year. Another step was taken when the Port of Salem, New Jersey announced that the Radiation Technology Model RT-4104

  20. Food irradiation seminar: Asia and the Pacific

    The report covers the Seminar for Asia and the Pacific on the practical application of food irradiation. The seminar assessed the practical application of food irradiation processes, commercial utilisation and international trade of irradiated food

  1. Safer food means food irradiation

    In this article the author presents the sanitary advantages that are brought by food irradiation. OMS experts state that this technique is safe and harmless for any average global dose between 10 KGy and 100 KGy. Whenever a seminar is held on the topic, it is always concluded that food irradiation should be promoted and favoured. In France food irradiation is authorized for some kinds of products and exceptionally above a 10 KGy dose. Historically food irradiation has been hampered in its development by its classification by American Authorities as food additives in 1958 (Delanay clause). The author draws a parallel between food irradiation and pasteurization or food deep-freezing in their beginnings. (A.C.)

  2. Eatability of the irradiated food

    A food is eatable and innocuous when it has an acceptable nutritional quality, it is toxicological and microbiologically safe for the human consumption. Not one preservation treatment allows to assure this in absolute form. As it happens with other conservation methods, the irradiation produce biological, chemical and physical changes in the treated food. For to check if such changes could cause damages to the health of the consumer, its have been carried out extensive studies to evaluate the inoculate of the irradiated foods. Analyzing diverse toxicity studies to prove the eatability of the irradiated foods, in this work those are presented but important in chronological order. In summary, until today it exists a great heap of tests that they demonstrate without place to doubts that the foods irradiated with a dose up to 10 KGy its are capable for the human consumption, for what can to be concluded that a safety margin exists to consume foods irradiated. (Author)

  3. Consumer acceptance of irradiated food

    There was a widely held opinion during the 1970's and 1980's that consumers would be reluctant to purchase irradiated food, as it was perceived that consumers would confuse irradiated food with food contaminated by radionuclides. Indeed, a number of consumer attitude surveys conducted in several western countries during these two decades demonstrated that the concerns of consumers on irradiated food varied from very concerned to seriously concerned.This paper attempts to review parameters conducting in measuring consumer acceptance of irradiated food during the past three decades and to project the trends on this subject. It is believed that important lessons learned from past studies will guide further efforts to market irradiated food with wide consumer acceptance in the future. (Author)

  4. Indication method of irradiated meat

    An injury of Chromosome DNA of irradiated meat was indicated by mitochondria DNA (mt DNA) method. Sample was irradiated by 60Co-γ ray at 6 kGy/h of dose rate at 0degC. Mitochondria DNA was obtained by the mitochondria partition method and analyzed by an electrophoresis method. mt DNA of irradiated ox liver can be indicated by PCR method, restriction enzyme method and supercoil/ring opening comparative method. However, the other meat such as chicken and other parts of meat could not be indicated depends on large fat content. About 4 kGy irradiation on liver can indicate whether it was irradiated or not. (S.Y.)

  5. Consumer acceptance of irradiated food

    Loaharanu, P. [Head, Food Preservation Section, Joint FAO/ IAEA Division of Nuclear Techniques in Food and Agriculture, Wagramerstr. 5, A-1400, Vienna (Austria)

    1997-12-31

    There was a widely held opinion during the 1970`s and 1980`s that consumers would be reluctant to purchase irradiated food, as it was perceived that consumers would confuse irradiated food with food contaminated by radionuclides. Indeed, a number of consumer attitude surveys conducted in several western countries during these two decades demonstrated that the concerns of consumers on irradiated food varied from very concerned to seriously concerned.This paper attempts to review parameters conducting in measuring consumer acceptance of irradiated food during the past three decades and to project the trends on this subject. It is believed that important lessons learned from past studies will guide further efforts to market irradiated food with wide consumer acceptance in the future. (Author)

  6. Irradiation environment and materials behavior

    Irradiation environment is unique for materials used in a nuclear energy system. Material itself as well as irradiation and environmental conditions determine the material behaviour. In this review, general directions of research and development of materials in an irradiation environment together with the role of materials science are discussed first, and then recent materials problems are described for energy systems which are already existing (LWR), under development (FBR) and to be realized in the future (CTR). Topics selected are (1) irradiation embrittlement of pressure vessel steels for LWRs, (2) high fluence performance of cladding and wrapper materials for fuel subassemblies of FBRs and (3) high fluence irradiation effects in the first wall and blanket structural materials of a fusion reactor. Several common topics in those materials issues are selected and discussed. Suggestions are made on some elements of radiation effects which might be purposely utilized in the process of preparing innovative materials. (J.P.N.) 69 refs

  7. Irradiated mandibular autografts

    The cosmetic and functional disability associated with mandibular resection has been a major problem to the patient with direct invasion of the mandible by oral cancer. Marginal resections with combined postoperative radiation therapy have frequently been substituted for the more preferred segmental resections and resultant deformities. Presented are 15 cases of oral cavity cancer involving resection of the mandible, immediate radiation to 10,000 rad, and primary reconstruction as irradiated mandibular autografts. The longest following is 4 years and 3 months, with a success rate of 66%. Morbidity is minimal as compared to autogenous bone grafting. Tumor size, previous radiation, or use of regional flaps have not been a factor in the success of this method in reconstruction of the mandible primarily

  8. Irradiation effects in glasses

    The deposition of irradiation energy can alter the physical properties of glasses through bond-breaking (energetic photons; fast particles) and atomic displacements (Coulombic and collisional: n0, e, ions). These processes can alter UV-visible optical properties via electron-hole trapping and IR-spectra as a result of network damage. The movement of network atoms results in volume dilatation which change the hardness, refractive index, and dissolution rates. All of these changes can be realized with ion implantation and, in addition, implantation of chemically active species can lead to compound formation in the implanted regions. For this reason, emphasis will be placed on the implantation-induced surface modifications of glasses (mostly silicates). The paper includes crystallization, surface stress, refractive index changes and optoelectronic application and chemical reactivity

  9. Irradiation preservation of Korean shellfish

    Pacific oyster, hard clam and mussel were irradiated at doses up to 0.5 Mrad, the optimum dose rather than the maximum permissible was sought for in each species and post-irradiation storage characteristics studied at 00 and 50C. No shellfish meat irradiated at doses as high as 0.5 Mrad produced any adverse odor. However the organoleptic quality of each sample irradiated at lower doses was superior to those irradiated at the higher during the early storage period. The optimum dose was determined to be 0.2 Mrad for Pacific oyster and mussel and 0.1 Mrad for hard clam. By irradiating at the optimum dose, the storage life of Pacific oyster could be extended from less than 14 days to 35 days at 00C and from only 3 days to 21 days at 50C. A similar storage extension was observed from 7 days to 14 days at 00C and from 3 days to 12 days at 50C. The hard clam meats were particularly susceptible to tissue softening by irradiation; an earlier onset and more extensive softening were observed with increasing dose. (author)

  10. Gamma Irradiation of Polyesters Film

    Experimental investigations on the effects of gamma irradiation in air of aromatic polyesters are carried out, in order to evaluate the influence of aromatic density and the role of oxygen on the radiation resistance. The thermoplastic polyesters PolyEthyleneTerephthalate (PET), PolyButylene Terephthalate (PBT), PolyEthyleneNaphthalate (PEN), Poly1,4-cyclohexanedimethylen terephthalate-co-ethyleneterephthalate (PCT-co-ET) are moulded in thin films of 50 micron and irradiated at different absorbed doses, ranging from 0 to 1000 kGy, using a Co-60 gamma source. The structural changes in the polymers are studied by means of several physical-chemical and nuclear techniques. Electron Paramagnetic Resonance analyses are carried out to detect the radicals induced by irradiation and to follow their decay by oxygen permeation. Viscometric measurements show a similar trend for the different irradiated polyesters: in particular, chain scission induced by irradiation depends on the aromatic density contained in the polymer and shows a saturation effect at the highest doses. Positron Annihilation Lifetime Spectroscopy points out a decrease of the ortho-positronium signal caused by the production of oxidized species inhibiting the positronium formation. Finally, the experimental results obtained on the irradiated films are compared with previous studies carried out on the same polyesters moulded in sheets of 1-2 mm of thickness and γ-irradiated at the same adsorbed doses

  11. Gamma-irradiation of tomatoes

    The influence of gamma-ray on tomatoes picked in a pink-red ripening stage, good for consumption, is studied. For that purpose tomatoes of ''Pioneer 2'' variety packed in perforated 500 g plastic bags were irradiated on a gamma device (Cobalt-60) at a dose power of 1900 rad/min with doses 200 or 300 krad. Samples were stored after irradiation at room temperature (20 - 22sup(o)C). Microbiological studies demonstrated that 44 resp. 99.96 per cent of the initial number of microorganisms was destroyed after irradiation with 200 resp. 300 krad. The time required for the number of microorganisms to be restored was accordingly increased. Irradiation delayed tomato ripening by 4 to 6 days, demonstrable by the reduced content of the basic staining substances - carotene and licopine. Immediately after irradiation the ascorbic acid content was reduced by an average of 13 per cent. After 18 days the amount of ascorbic acid in irradiated tomatoes was increased to a higher than the starting level, this is attributed to reductone formation during irradiation. The elevated total sugar content shown to be invert sugar was due to further tomato ripening. (Ch.K.)

  12. Method of detecting irradiated pepper

    Spices represented by pepper are generally contaminated by microorganisms, and for using them as foodstuffs, some sterilizing treatment is indispensable. However, heating is not suitable to spices, accordingly ethylene oxide gas sterilization has been inevitably carried out, but its carcinogenic property is a problem. Food irradiation is the technology for killing microorganisms and noxious insects which cause the rotting and spoiling of foods and preventing the germination, which is an energy-conserving method without the fear of residual chemicals, therefore, it is most suitable to the sterilization of spices. In the irradiation of lower than 10 kGy, the toxicity test is not required for any food, and the irradiation of spices is permitted in 20 countries. However, in order to establish the international distribution organization for irradiated foods, the PR to consumers and the development of the means of detecting irradiation are the important subjects. The authors used pepper, and examined whether the hydrogen generated by irradiation remains in seeds and it can be detected or not. The experimental method and the results are reported. From the samples without irradiation, hydrogen was scarcely detected. The quantity of hydrogen generated was proportional to dose. The measuring instrument is only a gas chromatograph. (K.I.)

  13. Nanoindentation on ion irradiated steels

    Radiation induced mechanical property changes can cause major difficulties in designing systems operating in a radiation environment. Investigating these mechanical property changes in an irradiation environment is a costly and time consuming activity. Ion beam accelerator experiments have the advantage of allowing relatively fast and inexpensive materials irradiations without activating the sample but do in general not allow large beam penetration depth into the sample. In this study, the ferritic/martensitic steel HT-9 was processed and heat treated to produce one specimen with a large grained ferritic microstructure and further heat treated to form a second specimen with a fine tempered martensitic lath structure and exposed to an ion beam and tested after irradiation using nanoindentation to investigate the irradiation induced changes in mechanical properties. It is shown that the HT-9 in the ferritic heat treatment is more susceptible to irradiation hardening than HT-9 after the tempered martensitic heat treatment. Also at an irradiation temperature above 550 deg. C no detectable hardness increase due to irradiation was detected. The results are also compared to data from the literature gained from the fast flux test facility.

  14. Microbiological Principles in Food Irradiation

    This paper reviews the important microbiological objectives of irradiation treatments, with special reference to the definitions of the proposed new terms, radappertization, radicidation and radurization. Emphasis is placed on the nature of the food in determining the microbiological requirements of the irradiation treatment. It is suggested that, just as with heat-processed foods, classifications into the major groups of ''acid'' or ''cured'' foods will remain valid with the irradiation process, and that different microbiological criteria will apply to these different classes of foods. The differences depend in part on the influence which the nature of the food has on the effectiveness of the irradiation treatment itself, but more especially on the way in which the nature of the food affects the activities of those microorganisms which might survive irradiation. The principles used to calculate the appropriate doses of radiation are discussed, with comments on the reliability of the fundamental assumptions or the need for further experimentation. The microbiological characteristics of irradiated foods are compared with those of corresponding heat- processed foods, to emphasize points of difference, with special reference to the appropriateness of suggested classifications for heat-processed foods. Finally, some general difficulties are considered, such as uncertainty about the significance and behaviour of food-borne viruses, and about the significance of the mutations which might conceivably be induced in microorganisms surviving-an irradiation process. (author)

  15. Detection of some irradiated foods

    This study was performed to investigate the possibility of using two rapid methods namely Supercritical Fluid Extraction (SFE) and Direct Solvent Extraction (DSE) methods for extraction and isolation of 2-dodecylcyclobutanone (2-DCB) followed by detecting this chemical marker by Gas chromatography technique and used this marker for identification of irradiated some foods containing fat (beef meat, chicken, camembert cheese and avocado) post irradiation, during cold and frozen storage. Consequently, this investigation was designed to study the following main points:- 1- The possibility of applying SFE-GC and DSE-GC rapid methods for the detection of 2-DCB from irradiated food containing fat (beef meat, chicken, camembert cheese and avocado fruits) under investigation.2-Studies the effect of gamma irradiation doses on the concentration of 2-DCB chemical marker post irradiation and during frozen storage at -18 degree C of chicken and beef meats for 12 months.3-Studies the effect of gamma irradiation doses on the concentration of 2-DCB chemical marker post irradiation and during cold storage at 4±1 degree C of camembert cheese and avocado fruits for 20 days.

  16. Irradiation's potential for preserving food

    The first experimental studies on the use of ionizing radiation for the preservation of foods were published over thirty years ago (1, 2) . After a period of high expectations and perhaps exaggerated optimism a series of disappointments occurred in the late '60s .The first company specifically created to operate a food irradiation plant, Newfield Products Inc, ran into financial difficulties and had to close its potato irradiation facility in 1966. The irradiator, designed to process 15,000t of potatoes per month for inhibition of sprouting, was in operation during one season only. In 1968 the US Food an Drug Administration refused approval for radiation-sterilisation of ham and withdrew the approval it had granted in 1963 for irradiated bacon. An International Project on the Irradiation of Fruit and Fruit juices, created in 1965 at Seibersdorf, Austria, with the collaboration or 9 countries, ended with general disappointment after three years. The first commercial grain irradiator, built in the Turkish harbour town of Iskenderun by the International Atomic Energy Agency with funds from the United Nations Development Program, never received the necessary operating licence from the Turkish Government and had to be dismantled in 1968. The US Atomic Energy Commission terminated its financial support to all research programmes on food irradiation in 1970. For a number of years, little chance seemed to remain that the new process would ever be practically used. However, research and development work was continued in a number of laboratories all over the world, and it appears that the temporary setbacks now have been overcome. Growing quantities of irradiated foods are being marketed in several countries and indications are that irradiated foods will eventually be as generally accepted as are frozen, dried or heatsterilised foods

  17. Pork fat peroxidation by gamma-irradiation

    In this paper, pork fat peroxidation by γ-irradiation and the possible effects of oxygen, UV-irradiation and storage after the γ-irradiation have been investigated. It has been found that the level of peroxides in irradiated pork increases linearly with the increasing absorbed dose. The chemical yield of peroxides formed in the irradiated fat is about 4.2 and independent on the sample temperature or absorbed dose rate, but dependent on storage time of sample before γ-irradiation. The irradiated pork exhibits some unusual features as following: 1) the peroxide content in irradiated pork is higher than that in unirradiated one; 2) the peroxide content in irradiated pork increases gradually on storage and is essentially constant in unirradiated one, which is very useful for the detection of irradiated pork; 3) the further peroxidation in irradiated pork is much more susceptible to UV radiation than that in unirradiated pork

  18. Facts about food irradiation: Irradiation and food additives and residues

    This fact sheet considers the issue of the irradiation of food containing food additives or pesticide residues. The conclusion is that there is no health hazard posed by radiolytic products of pesticides or food additives. 1 ref

  19. New facility for post irradiation examination of neutron irradiated beryllium

    Ishitsuka, Etsuo; Kawamura, Hiroshi [Oarai Research Establishment, Ibaraki-Ken (Japan)

    1995-09-01

    Beryllium is expected as a neutron multiplier and plasma facing materials in the fusion reactor, and the neutron irradiation data on properties of beryllium up to 800{degrees}C need for the engineering design. The acquisition of data on the tritium behavior, swelling, thermal and mechanical properties are first priority in ITER design. Facility for the post irradiation examination of neutron irradiated beryllium was constructed in the hot laboratory of Japan Materials Testing Reactor to get the engineering design data mentioned above. This facility consist of the four glove boxes, dry air supplier, tritium monitoring and removal system, storage box of neutron irradiated samples. Beryllium handling are restricted by the amount of tritium;7.4 GBq/day and {sup 60}Co;7.4 MBq/day.

  20. Irradiation a boon to farmers

    Irradiation sterilization is emerging as a process of tremendous value to the food marketing industry. Much of the latest research has been done by the Atomic Energy Board at Pelindaba, using the strong gamma rays produced by cobalt-60 to kill the pathogens, microprobes, small insects and other food destroying agents usually found in food and fruit. Irradiation also helps delay ripening and ageing to a slight degree, a property of great value to food and fruit exporters. The advantages of various irradiated food are shortly discussed

  1. Irradiation services for crops improvement

    As an effort to pioneer and promote the use of nuclear technology in plant breeding in Malaysia, MINT has developed the procedures, methodology and service for the irradiation of ornamental plants, food and industrial crops. This paper discusses the issues related to the irradiation services for plant samples for the period of 15 years since the service was started. The main issues include the procedures for sample irradiation, statistics for the services that have been provided, problems and the solutions in providing the services. (Author)

  2. Nutritional Value of Irradiated Potatoes

    Rats received dried potatoes, irradiated with 10 krad, in an amount of 72% of the diet. Control groups received the same amount of non-irradiated potatoes. The experiment began on 7 May 1965 and is still running. To date, there is no difference between the groups fed with irradiated potatoes and the controls as far as weight gain and protein efficiency are concerned. Another experiment has been running for 12 weeks under the same conditions, except that the radiation dose was 100 krad. Here, too, no difference to the control groups can be observed. (author)

  3. International status of food irradiation

    Recent international moves that are likely to result in an increasing acceptance of irradiated foods are reviewed. Particular attention is given to the activities of the FAO, WHO, Codex Alimentarius and to attitudes in the United States and the Asian-Pacific region. In 1979, the Codex Alimentarius Commission adopted a Recommended General Standard for Irradiated Food. A resume is given of a revised version of the standard that is presently under consideration. However, remaining barriers to trade in irradiated food are briefly discussed, such as legal and regulatory problems, labelling, public acceptance and economic viability

  4. AFIP-4 Irradiation Summary Report

    The Advanced Test Reactor (ATR) Full size plate In center flux trap Position (AFIP) experiment AFIP-4 was designed to evaluate the performance of monolithic uranium-molybdenum (U-Mo) fuels at a scale prototypic of research reactor fuel plates. The AFIP-4 test further examine the fuel/clad interface and its behavior under extreme conditions. After irradiation, fission gas retention measurements will be performed during post irradiation (PIE). The following report summarizes the life of the AFIP-4 experiment through end of irradiation, including a brief description of the safety analysis, as-run neutronic analysis results, hydraulic testing results, and thermal analysis results.

  5. Methodology for RPV steels irradiations

    As a result of the popularity of the Agencies report 'Neutron Irradiation Embrittlement of Reactor Pressure Vessel Steels' of 1975, it was decided that another report on this broad subject would be of use. In this report, background and contemporary views on specially identified areas of the subject are considered as self-contained chapters, written by experts. The methodology for reactor pressure vessel (RPV) steels irradiations is elaborated. Irradiation in a materials test reactor and surveillance of the state of embrittlement in 'typical' plant specific materials are considered

  6. Food irradiation, profits and limitations

    The utility of the irradiation to overcome diverse problems of lost nutritious, it has been demonstrated in multiple investigation works, that its have confirmed the value and the inoculation of the irradiated foods. The quantity of energy applied to each food, is in function of the wanted effect. In this document a guide with respect to the practical application and the utility of the irradiation process in different foods, as well as the suggested dose average is shown. Among the limitations of the use of this technology, its are the costs and not being able to apply it to some fresh foods. (Author)

  7. Food irradiation dispelling the doubts

    Irradiation processing of the food item eliminates the use of harmful chemicals for treatment of food items and the produce can be conserved fresh. Another important aspect of this process is that it can help to stabilize the prices and give better remuneration to the farmer and hygienic product to the consumer. The already growing Indian nuclear industry can provide the source as well as the pros and cons of food technology for installation of irradiation facilities. The pros and cons of irradiation process are described. (M.K.V.)

  8. Growing acceptance of food irradiation

    In the table are listed food products treated by irradiation which have been cleared for human consumption in a number of Member States of the Agency. The details are based on information up to 1 February 1968. Two words already known to food experts investigating nuclear techniques for preserving food and preventing wastage but perhaps unfamiliar as yet to others, appear in the table. They are radappertization and radurization. The first means sterilization by irradiation and the second extension of market life, also by irradiation. (author)

  9. Therapeutic postprostatectomy irradiation.

    Youssef, Emad; Forman, Jeffrey D; Tekyi-Mensah, Samuel; Bolton, Susan; Hart, Kim

    2002-06-01

    The purpose of this study was to determine the outcome of patients receiving external beam radiation for an elevated postprostatectomy prostate-specific antigen (PSA) level. Between December 1991 and September 1998, 108 patients received definitive radiation therapy for elevated postprostatectomy PSA levels. The median dose of irradiation was 68 Gy (range, 48-74 Gy). During treatment, the PSA levels were checked an average of 5 times (range, 3-7 times). Prostate-specific antigen values were judged to decline or increase during treatment if they changed by more than 0.2 ng/mL. After treatment, biochemical failure was defined as a measurable or rising PSA > 0.2 ng/mL. Median follow-up was 51 months (range, 3-112 months). Fifty-eight patients (54%) had evidence of biochemical failure. The 3- and 5-year actuarial biochemical relapse-free (bNED) survivals for all patients were 55% and 39%, respectively. Upon univariate analysis, intratreatment PSA and preradiation PSA were significant predictors of bNED survival. Patients with a PSA level that decreased during treatment had a 5-year bNED survival of 43% compared to 10% in patients with an increasing PSA level (P = 0.0002). Using the preradiation therapy PSA value as a continuous variable, higher preradiation therapy PSA levels were associated with an increased risk of failure (P = 0.004). Cut points of pretreatment PSA were derived at 0.9 ng/mL and 4.2 ng/mL using the Michael Leblanc recursive partitioning algorithm. The 5-year bNED rate for patients with a preradiation therapy PSA or = 4.2 ng/mL (P = 0.0003). Patients with a Gleason score of 7 (P = 0.27). Other factors examined individually that did not reach statistical significance included time from surgery to radiation therapy, race, seminal vesicle involvement, pathological stage, surgical margin, and perineural invasion. Upon multivariate analysis, only preradiation therapy PSA (P < 0.001) and the PSA trend during radiation therapy (P < 0.001) were significant

  10. Currently developing opportunities in food irradiation and modern irradiation facilities

    I. Factor currently influencing advancing opportunities for food irradiation include: heightened incidence and awareness of food borne illnesses and causes. Concerns about ensuring food safety in international as well as domestic trade. Regulatory actions regarding commonly used fumigants/pesticides e.g. Me Br. II. Modern irradiator design: the SteriGenics Mini Cell. A new design for new opportunities. Faster installation of facility. Operationally and space efficient. Provides local onsite control. Red meat: a currently developing opportunity. (Author)

  11. Facts about food irradiation: Safety of irradiation facilities

    This fact sheet considers the safety of industrial irradiation facilities. Although there have been accidents, none of them has endangered public health or environmental safety, and the radiation processing industry is considered to have a very good safety record. Gamma irradiators do not produce radioactive waste, and the radiation sources at the facilities cannot explode nor in any other way release radioactivity into the environment. 3 refs

  12. (Irradiation creep of graphite)

    Kennedy, C.R.

    1990-12-21

    The traveler attended the Conference, International Symposium on Carbon, to present an invited paper, Irradiation Creep of Graphite,'' and chair one of the technical sessions. There were many papers of particular interest to ORNL and HTGR technology presented by the Japanese since they do not have a particular technology embargo and are quite open in describing their work and results. In particular, a paper describing the failure of Minor's law to predict the fatigue life of graphite was presented. Although the conference had an international flavor, it was dominated by the Japanese. This was primarily a result of geography; however, the work presented by the Japanese illustrated an internal program that is very comprehensive. This conference, a result of this program, was better than all other carbon conferences attended by the traveler. This conference emphasizes the need for US participation in international conferences in order to stay abreast of the rapidly expanding HTGR and graphite technology throughout the world. The United States is no longer a leader in some emerging technologies. The traveler was surprised by the Japanese position in their HTGR development. Their reactor is licensed and the major problem in their graphite program is how to eliminate it with the least perturbation now that most of the work has been done.

  13. Generic phytosanitary irradiation treatments

    The history of the development of generic phytosanitary irradiation (PI) treatments is discussed beginning with its initial proposal in 1986. Generic PI treatments in use today are 150 Gy for all hosts of Tephritidae, 250 Gy for all arthropods on mango and papaya shipped from Australia to New Zealand, 300 Gy for all arthropods on mango shipped from Australia to Malaysia, 350 Gy for all arthropods on lychee shipped from Australia to New Zealand and 400 Gy for all hosts of insects other than pupae and adult Lepidoptera shipped to the United States. Efforts to develop additional generic PI treatments and reduce the dose for the 400 Gy treatment are ongoing with a broad based 5-year, 12-nation cooperative research project coordinated by the joint Food and Agricultural Organization/International Atomic Energy Agency Program on Nuclear Techniques in Food and Agriculture. Key groups identified for further development of generic PI treatments are Lepidoptera (eggs and larvae), mealybugs and scale insects. A dose of 250 Gy may suffice for these three groups plus others, such as thrips, weevils and whiteflies. (author)

  14. Economics of Grain Irradiation

    After three years, in which preliminary designs were prepared, a grain irradiation plant has been designed and is being built into an existing silo installation. From this experience actual costs of plant construction are available for a plant using cobalt-60 and this experience is incorporated in estimates for machine installations for high grain throughput. Costs are compared for plants of comparable complexity and they indicate those areas in which each type of plant is pre-eminently suitable and those areas where either type may be best, dependent upon local site conditions, the standard of local technology and methods of operation. The two plants compared are described in sufficient detail to enable the precise extent of the equipment supply covered by the costs to be appreciated. The accounting methods employed have been discussed with industrial accountants to ensure that they are acceptable to the potential users. The methods employed are explained so that they can be applied to problems of a similar nature. (author)

  15. Development of blood irradiators

    The fully portable, vitreous-carbon/thulium-170 (VCTm) irradiators were previously developed and tested in goats, sheep and dogs for effects on circulating lymphocytes and on skin graft rejection. This past year the testing was extended to include studies of effects on kidney transplants in dogs. Six pairs of beagle dogs were tested. One of each pair was treated with an activated VCTm (i.e., containing 170Tm); the other was treated comparably, but had an inactive unit (containing 169Tm). Kidney donors were selected for maximum disparity in cellular immune (DLA) type between donor and host. The host's own kidneys were removed so that survival depended on the functioning of the transplanted kidney. The untreated dogs survived 9 to 23 days (mean = 15) after transplant; treated dogs survived 16 to 45 days (mean = 27 days). Histological examination showed that there was a distinct depletion of cells in all lymphoid tissues and a reduced cellular involvement in kidney tissues of treated animals

  16. Irradiation of food - the facts

    The author outlines the history of the process for the interest of the baking industry, and discusses the difficulties concerning public relations in this field, before the introduction of irradiation to the British food industry. (U.K.)

  17. Finely divided, irradiated tetrafluorethylene polymers

    Dry non-sticky fine lubricant powders are made by γ-irradiation of unsintered coagulated dispersion grade tetrafluoroethylene polymers. These powders may also be dispersed in an organic medium for lubricating purposes

  18. Gamma irradiators for radiation processing

    Radiation technology is one of the most important fields which the IAEA supports and promotes, and has several programmes that facilitate its use in the developing Member States. In view of this mandate, this Booklet on 'Gamma Irradiators for Radiation Processing' is prepared which describes variety of gamma irradiators that can be used for radiation processing applications. It is intended to present description of general principles of design and operation of the gamma irradiators available currently for industrial use. It aims at providing information to industrial end users to familiarise them with the technology, with the hope that the information contained here would assist them in selecting the most optimum irradiator for their needs. Correct selection affects not only the ease of operation but also yields higher efficiency, and thus improved economy. The Booklet is also intended for promoting radiation processing in general to governments and general public

  19. URAM-2 Cryogenic Irradiation Facility

    Shabalin, E P; Kulikov, S A; Kulagin, E N; Melihov, V V; Belyakov, A A; Golovanov, L B; Borzunov, Yu T; Konstantinov, V I; Androsov, A V

    2002-01-01

    The URAM-2 irradiation facility has been built and mounted at the channel No. 3 of the IBR-2 reactor. It was constructed for study of radiolysis effects by fast neutron irradiation in some suitable for effective cold neutron production materials (namely: solid methane, methane hydrate, water ice, etc.). The facility cooling system is based on using liquid helium as a coolant material. The original charging block of the rig allows the samples to be loaded by condensing gas into irradiation cavity or by charging beads of ice prepared before. Preliminary tests for each facility block and assembling them at the working position were carried out. Use of the facility for study accumulation of chemical energy under irradiation at low temperature in materials mentioned above and its spontaneous release was started.

  20. Irradiation emerges as processing alternative

    Anticipating that food irradiation may soon become an important addition to the many food processing techniques currently available, this article discusses many aspects of this process. Primarily, the benefits of irradiation for all foods include insect and bacterial control, increasing the potential to reduce incidences of food-borne illnesses, in addition to delaying the deterioration of fruits and vegetables. Currently approved uses of food irradiation in the U.S. and other countries, a summary of the proposed rule for wider application, and the labeling issue encompassed in the proposal are addressed. Additionally, the areas of great consumer concern--safety and public health implications, are talked about with the conclusion that food irradiation has been declared safe

  1. Gamma irradiators: developments in India

    A comprehensive programme for the production of 60Co sources and their applications was initiated at the Bhabha Atomic Research Centre in 1970. Initially a series of research irradiators called Gamma Chambers and Panoramic Batch Irradiators (PANBITs) was fabricated for R and D and pilot scale studies. In 1974 the first commercial scale, gamma sterilization plant ISOMED was commissioned with UNDP assistance. Subsequently two more plants were designed and built indigenously, one at Bangalore and the other at Delhi. A radiation plant for sludge hygienisation was built at Baroda and commissioned in 1992. The current interest in radiation vulcanization of natural rubber latex (NRL) prompted the development and commissioning of a pilot scale NRL, irradiator at Kottayam, Kerala in 1992. A multipurpose irradiator is built recently at Jodhpur, as an upgraded version of the vintage PANBIT. Salient feature of these plants are presented . (author). 6 figs

  2. URAM-2 cryogenic irradiation facility

    The URAM-2 irradiation facility has been built and mounted at channel No.3 of the IBR-2 reactor. It was constructed for study of radiolysis effects by fast neutron irradiation in some suitable for effective cold neutron production materials (namely: solid methane, methane hydrate, water ice, etc.). The facility cooling system is based on using liquid helium as a coolant material. The original charging block of the rig allows the samples to be loaded by condensing gas into irradiation cavity or by charging beads of ice prepared before. Preliminary tests for each facility block and assembling them at the working position were carried out. Use of the facility for studying accumulation of chemical energy under irradiation at low temperature in materials mentioned above and its spontaneous release was started

  3. Irradiation of spices and herbs

    Changes in the microbiology, chemistry, mutagenicity and sensory of spices due to gamma irradiation are discussed. This process has been shown to be safe and wholesome with no effect on product quality or flavour

  4. HACCP, food quality, food irradiation

    The paper summarizes the principles and purposes of the ''Hazard Analysis Critical Control Points'' (HACCP) system and its application and implementation within the European Union for the purposes of food quality and safety control, including food irradiation. (orig./CB)

  5. Massive allografts sterilised by irradiation

    From 1984 to 1988 we implanted 127 massive allografts irradiated with a dose of 25 000 grays. These were reviewed at a minimum follow-up of three years to determine the effect of irradiation on infection, the complications and the functional result. No bacteriological infection was seen in the 44 patients who had allografts for revision of joint arthroplasty or for a tumour with no adjuvant therapy. For the 83 patients who also had chemotherapy or radiotherapy or both for a bone tumour, the rate of infection was 13%. The major mechanical complications were nonunion in seven grafts (5.5%) and fracture in eight (6%). These rates do not differ greatly from those reported for non-irradiated grafts. Our results suggest that irradiation, which remains the most convenient and acceptable method of sterilisation, does not jeopardise the clinical results. (author)

  6. Detection of irradiated food: Perspectives

    Apart from the administrative monitoring procedures, - documentation by the irradiation facility operators and the documents accompanying irradiated foods -, reliable methods for food testing and post-factum detection of foods treated with ionizing radiation are required. The paper reviews the methods available for this purpose, summarizes results of the interlaboratory comparisons performed for verification, and lists the mandatory procedures required by the law. It is important to note that methods are available today that will detect unauthorized irradiation in almost any of the foods that are suitable for radiation treatment. In addition, the available methods are improved and refined whenever possible. The results of monitoring and testing activities so far according to the food surveillance regime in Germany show that there are only few irradiated foods on the market. (orig./cB)

  7. Food irradiation in South Africa

    The article indicates the necessity for additional methods of food preservation and emphasises that food irradiation is developing into an important method of food preservation because it has been proved scientifically and practically that food irradiation can be applied effectively; also that there is absolute certainty that radiation-processed products are safe and nutritious and that such food is acceptable to the consumer and food trade, also with a view to costs. It discusses the joint food irradiation programme of the AEB and Department of Agriculture and Fisheries and points out that exemption for the irradiation of potatoes was already obtained in 1977 and later for mango's, paw-paws, chicken, onions, garlic and strawberries. Conditional exemption was obtained for avocado's and dried bananas. Other food-kinds on which research is being continued are grapes, melons, mushrooms, stone fruit and spices

  8. Slag recycling of irradiated vanadium

    An experimental inductoslag apparatus to recycle irradiated vanadium was fabricated and tested. An experimental electroslag apparatus was also used to test possible slags. The testing was carried out with slag materials that were fabricated along with impurity bearing vanadium samples. Results obtained include computer simulated thermochemical calculations and experimentally determined removal efficiencies of the transmutation impurities. Analyses of the samples before and after testing were carried out to determine if the slag did indeed remove the transmutation impurities from the irradiated vanadium

  9. The facts behind food irradiation

    In this, the second of a two part article, professor Bert McGill completes his investigation of the process of food irradiation. He looks at some of the literature released on food irradiation and the complications thereof. He shows on half truths, innuendos and statements taken out of context, prepared to present only that picture which it wants to present, as it comes forward in documentation

  10. Preliminary studies on irradiated spirulina

    In the last decades, a special attention is given to study different algae, especially to microscopic ones. Spirulina is one of them being used both nutritive supplement and medicine. The aim of the paper is to study the electron beam irradiated Spirulina by physical and biochemical methods. The UV-Vis and EPR (electron paramagnetic resonance) spectra and antioxidant activity are presented for Spirulina irradiated up to 80 kGy. (authors)

  11. Irradiation injury to large arteries

    Four cases of irradiation injury to large arteries following radiotherapy treatment are presented and the literature is reviewed. Three patterns of injury have emerged: 1) intimal damage resulting in mural thrombosis presenting within 5 years of irradiation, 2) fibrotic occlusion presenting within 10 years of injury, and 3) a predisposition to the development of atheroma together with periarterial fibrosis associated with a latent interval of 20 or more years. The treatment of choice is a bypass procedure of the arterial lesion. (author)

  12. A Mobile Irradiator Design Study

    The need for data on the technical and economic feasibility of commercial potato irradiation using Cobalt-60 gamma rays, led to a design and cost study of a mobile irradiator. Investigation of handling and storage of potatoes in major growing areas in Canada and the United States showed that the irradiator should process at least 6,000 lbs. (2,700 kilos) per hour in bulk or in 100 lb. (45 kilo) bags. Tests on irradiated potatoes indicated that a dose of 8,000 rads would effectively inhibit sprouting at a storage temperature of 68oF (20oC). Based on source configurations of other AECL irradiation facilities, calculations and measurements of dosage uniformity were made showing that ±33 per cent variation occurred when using two passes on each side of the line source. The source was designed to have increased activity near the ends. The calculated radiation utilization efficiency was 48 per cent. A truck-mounted irradiator was studied in some detail and was found to be too heavy for easy transportation. An irradiator using a railroad flatcar and weighing 60 tons (54,000 kilos) was then considered. Although its movement is restricted, most potato warehouses are located near railroad sidings and are easily reached by a railroad car. The processing cost, including depreciation, source replacement and operating costs, was estimated to be 0.9 per cent per lb. (2.0 cents per kilo) for 1,200 hours operation per year. A longer operation time per year results in a decrease in this processing cost. The above figure is based on estimated costs for a prototype unit. Somewhat lower costs are indicated for production irradiators. (author)

  13. Studies on the irradiated solids

    The 1988 progress report of the Irradiated Solids laboratory (Polytechnic School, France), is presented. The Laboratory activities concern the investigations on disordered solids (chemical or structural disorder). The disorder itself, its effects on the material physical properties and the particle-matter interactions, are investigated. The research works are performed in the following fields: solid state physics, irradiation and stoechiometric defects, and nuclear materials. The scientific reviews, the congress communications and the thesis are listed

  14. Nutritional value of irradiated food

    Statements made in 2 reports by the European Parliamentary Commission on the Environment, Public Health and Consumer Protection, chaired on both occasions by members of the German Green Party, that irradiated foods have no nutritional value are challenged. Attempts by the European Commission to regulate food irradiation in the European Community have been turned down by the European Parliament on the basis of these reports

  15. Legislations the field of food irradiation

    An outline is given of the national legislation in 39 countries in the field of food irradiation. Where available the following information is given for each country: form of legislation, object of legislation including information on the irradiation treatment, the import and export trade of irradiated food, the package labelling and the authorization and control of the irradiation procedures

  16. ATLAS Pixel Group - Photo Gallery from Irradiation

    2001-01-01

    Photos 1,2,3,4,5,6,7 - Photos taken before irradiation of Pixel Test Analog Chip and Pmbars (April 2000) Photos 8,9,10,11 - Irradiation of VDC chips (May 2000) Photos 12, 13 - Irradiation of Passive Components (June 2000) Photos 14,15, 16 - Irradiation of Marebo Chip (November 1999)

  17. Study on irradiation treatment to drunk crab

    For guaranteeing the quality of irradiated drunk crab, manufacture method of the dosimeter, sample setting and taking position, irradiation time, asymmetry degree of irradiation dose, contrast of the dosimeter are discussed and some reference datum to commercialization of drunk crab's irradiation are provided

  18. China's move to food irradiation

    The Chinese officials outlined China's past and future directions at a recent international food irradiation seminar in Shanghai sponsored by the FAO and IAEA. The meeting was attended by about 170 participants from China and 22 other countries, primarily from the Asian and Pacific region. Three food irradiation plants currently are operating in the region and 14 more are planned over the next 5 years. It was reported that China continues to suffer high food losses, up to 30% for some commodities, primarily due to preservation and storage problems. In January 1986, the first of five regional irradiation facilities planned in China officially opened in Shanghai. The Shanghai irradiation centre plans to process up to 35,000 tons of vegetables a year, as well as some spices, fruits, and non-food products. The Ministry of Public Health has approved seven irradiated foods as safe human diets: rice, potatoes, onions, garlic, peanuts, mushrooms and pork sausages; approval for apples is expected shortly. The Chinese officials at the Shanghai meeting stressed their openness to foreign participation and cooperation in food irradiation's development

  19. Irradiated vaccines against bovine babesiosis

    Experiments were conducted on non-splenectomized Bos taurus calves to determine the immunogenicity of blood vaccines containing either Babesia bigemina or Babesia bovis parasites irradiated in a 60Co source. Groups of calves between 6 and 10 months of age, found to be free of previous babesial infections by serodiagnosis, were inoculated with B. bigemina ('G' isolate) irradiated at rates ranging from 350 to 500 Gy. These vaccines caused low to moderate reactions on primary inoculation which subsided without treatment. Parasites irradiated at 350 Gy produced a strong immunity against virulent homologous challenge. Vaccinated calves also withstood virulent heterologous B. bigemina ('H' isolate) and B. bovis ('A' isolate) challenges made 85 and 129 days later. It also became evident that the use of babesicides to control reactions should be avoided since early treatment of 'reactor' animals caused breakdown of immunity among vaccinates. B. bovis ('A' isolate) parasites irradiated at dose rates of either 300 Gy or 350 Gy caused mild to moderate reactions in immunized calves, with the reactions in the 300 Gy group being slightly more severe. On challenge with homologous parasites, animals that had previously been inoculated with organisms irradiated at 300 Gy showed better protection than those that had received parasites irradiated at 350 Gy. (author). 28 refs, 5 tabs

  20. Material Irradiation at HANARO, Korea

    The High-flux Advanced Neutron Application Reactor (HANARO: High flux Advanced Neutron Application Reactor) is an open-pool type multi-purposed research reactor located at KAERI, in Korea. It was designed to provide a peak thermal and fast flux of 5x1014 n/cm2.s and 2.1x1014 n/cm2.s (E >1.0MeV) respectively at a 30 MW maximum thermal power. A capsule system has been developed for irradiation tests of nuclear materials and fuels in the core region of the HANARO reactor. Extensive efforts have been made to establish the design and manufacturing technology for a capsule and temperature control system, which should be compatible with HANARO's characteristics. A material capsule system consisting of main capsule, fixing, control, cutting, and transport system were developed for an irradiation test of non-fissile materials. This capsule system has been actively utilized for the various material irradiation tests requested by users from research institutes, universities and the industries. More than 7000 specimens have been irradiated at dedicated vertical hole of HANARO by using the developed capsule system since 1995. Based on the accumulated experience and the user's sophisticated requirements, new instrumented capsule technologies for a more precise control of the irradiation condition are being developed at HANARO. A strategic irradiation program at HANARO will place more emphasis on a special-purpose capsule system by focusing on the specific material or fuels for a next generation power reactor. (author)

  1. Identification methods for irradiated wheat

    The effect of irradiation on wheat seeds was examined using various kinds of analytical methods for the identification of irradiated seeds. In germination test, the growth of sprouts was markedly inhibited at 500Gy, which was not affected by storage. The decrease in germination percentage was detected at 3300Gy. The results of enzymatic activity change in the germ measured by Vita-Scope germinator showed that the seeds irradiated at 10kGy could be identified. The content of amino acids in ungerminated and germinated seeds were analyzed. Irradiation at 10kGy caused the decrease of lysine content but the change was small which need very careful operation to detect it. The chemiluminescence intensity increased with radiation dose and decreased during storage. The wheat irradiated at 10kGy could be identified even after 3 months storage. In the electron spin resonance (ESR) spectrum analysis, the signal intensity with the g value f 2.0055 of skinned wheat seeds increased with radiation dose. Among these methods, germination test was the most sensitive and effective for identification of irradiated wheat. (author)

  2. The present situation of irradiation services

    The present state of food irradiation in Japan is presented from a point of view of a trustee for irradiation business. Radiation sprout inhibition of potatoes, only approved by Government, and spice treatment, now being applied for, are explained. Existing establishments capable of entrusting irradiation services as business in Japan are outlined including Co-60 gamma ray and X-ray irradiation and electron beam irradiation. Principles of irradiation-induced physical and chemical effects in irradiated materials specifically organic polymers and brief explanation of facilities together with safety devices are also explained. (S. Ohno)

  3. Study on public acceptance of irradiated potatoes

    4,500 kg potatoes of different sorts were irradiated by a 137Cs source with a dose of 10 krad. The potatoes were then stored for several months at a room temperature of 6 to 100C and a humidity of 80 to 85%. 0% of the irradiated potatoes sprouted, as compared to 100% of the non-irradiated potatoes. The percentage of rotting varied in the irradiated potatoes, depending on the variety. Cooking tests showed no difference between irradiated and non-irradiated potatoes. The irradiated potatoes were consumed and accepted by about 4,000 persons in the cafeteria of the institute. (AJ)

  4. Food irradiation newsletter. Vol. 15, no. 2

    This newsletter contains brief summaries of three coordinated research meetings held in 1991: irradiation in combination with other processes for improving food quality; application of irradiation technique for food processing in Africa; and food irradiation programme for Middle East and European countries. The first Workshop on Public Information on Food Irradiation is summarized, and a Coordinated Research Programme on Irradiation as a Quarantine Treatment of Mites, Nematodes and Insects other than Fruit Fly is announced. This issue also contains a report on the status of food irradiation in China, and a supplement lists clearances of irradiated foods. Tabs

  5. Ripening characteristics of light irradiated tomatoes

    Red color development in breaker stage tomatoes was accelerated by 3 min red (R) irradiation and delayed by 3 min far-red (FR) irradiation during the first 4 days of ripening. The effects were reversible and color development effective whether the interval between R and FR treatments was 1 day or 2 days. Firmness values of tomatoes irradiated with R were lower than those irradiated with FR, treated with ethylene, or stored in darkness. Light irradiation had the greatest effect on color development in tomatoes irradiated at the breaker and turning stages of maturity compared to those irradiated at the pink and light red stages

  6. The sensory quality of irradiated mushrooms

    Forced triangle tests indicated some significant differences between unirradiated and irradiated mushrooms. The irradiated mushrooms were significantly stronger flavoured and firmer than unirradiated mushrooms. The panelists showed no significant preference for either the irradiated or unirradiated mushrooms. The combination of irradiation at 2kGy with pre-packing and storage reduced weight loss in mushrooms and prevented excessive stalk elongation. Irradiation inhibited cap opening. Generally pre-packed irradiated mushrooms discoloured more slowly than unirradiated pre-packed samples. The texture of pre-packed irradiated mushrooms tended to be firmer than that of unirradiated samples. (author). 15 refs, 3 figs, 5 tabs

  7. Improvement of irradiation facilities performance in JMTR

    Various kinds of irradiation facilities are installed in the JMTR for the purpose of irradiation tests on fuels and materials and of producing radioisotopes. The irradiation facilities have been improved so far at every opportunity of new irradiation requirements and of renewing them which reached the design lifetime. Of these irradiation facilities, improvements of the power ramping test facility (BOCA/OSF-1 facility) and the hydraulic rabbit No.2 (HR-2 facility) are described here. (author)

  8. Changes of lipids in irradiated chickens

    Chickens were irradiated in a 6deg Co gamma irradiation source. The irradiation has been done to reduce or eliminate Salmonella. The experiments were done to test this decontamination method of chickens if changes of lipids take place. It was to be seen, that peroxidation of lipids was more rapidly as in control. The time of storage of irradiated chickens has to be shorter because of changes in lipids. After irradiation the chickens had trade quality. (orig.)

  9. Chemical aspects of irradiated mangoes

    Mango is an important and very popular tropical fruit. Because of its short shelf life, however, its use is restricted to the areas of production. Since mango is a climacteric fruit, it is possible to extend its shelf life by delaying the ripening process and senescence by irradiation. The ripening process is very complex: it appears that the radiation-induced delay in ripening may be mediated through the inhibition of the enzyme(s) involved in ethylene production. The dose required for shelf-life extension is ≤1.5 kGy. Higher doses can lead to scalding, flesh darkening and development of hollow pockets. This review focuses on the chemical aspects of radiation-induced shelf-life extension of mangoes. At the low irradiation doses required for this shelf-life extension (≤1.5 kGy), the chemical effects are negligible. Irradiation does not affect the carotenoid levels, and has only a minor effect on the vitamin C level in a few mango varieties. No significant differences in the free and total (hydrolyzed) amino acids, or the protein content of Kent mangoes, have been detected between irradiated and unirradiated samples. During ripening of the mangoes the reducing sugar and the total sugar levels increase, but in the majority of the mango varieties these levels remain very similar in irradiated and unirradiated samples. There are some differences in the volatile compounds between irradiated and unirradiated Kent mangoes; however, these differences have no apparent effect on the taste and flavor of the irradiated mangoes

  10. Independent Laboratory for Detection of Irradiated Foods. Detection of the irradiated food in the INCT

    Lecture shows different methods applied for detection of irradiated foods. Structure and equipment of the Independent Laboratory for Detection of Irradiated Foods operating in the INCT is described. Several examples of detection of food irradiation are given in details

  11. Composting of sewage sludge irradiated

    Recently, the development of the techniques to return sewage sludge to forests and farm lands has been actively made, but it is necessary to assure its hygienic condition lest the sludge is contaminated by pathogenic bacteria. The research to treat sewage sludge by irradiation and utilize it as fertilizer or soil-improving material has been carried out from early on in Europe and America. The effects of the irradiation of sludge are sterilization, to kill parasites and their eggs, the inactivation of weed seeds and the improvement of dehydration. In Japan, agriculture is carried out in the vicinity of cities, therefore it is not realistic to use irradiated sludge for farm lands as it is. The composting treatment of sludge by aerobic fermentation is noticed to eliminate the harms when the sludge is returned to forests and farm lands. It is desirable to treat sludge as quickly as possible from the standpoint of sewage treatment, accordingly, the speed of composting is a problem. The isothermal fermentation experiment on irradiated sludge was carried out using a small-scale fermentation tank and strictly controlling fermentation conditions, and the effects of various factors on the fermentation speed were studied. The experimental setup and method are described. The speed of composting reached the maximum at 50 deg C and at neutral or weak alkaline pH. The speed increased with the increase of irradiation dose up to 30 Mrad. (Kako, I.)

  12. Plasmodium falciparum: attenuation by irradiation

    Waki, S.; Yonome, I.; Suzuki, M.

    1983-12-01

    The effect of irradiation on the in vitro growth of Plasmodium falciparum was investigated. The cultured malarial parasites at selected stages of development were exposed to gamma rays and the sensitivity of each stage was determined. The stages most sensitive to irradiation were the ring forms and the early trophozoites; late trophozoites were relatively insensitive. The greatest resistance was shown when parasites were irradiated at a time of transition from the late trophozoite and schizont stages to young ring forms. The characteristics of radiosensitive variation in the parasite cycle resembled that of mammalian cells. Growth curves of parasites exposed to doses of irradiation upto 150 gray had the same slope as nonirradiated controls but parasites which were exposed to 200 gray exhibited a growth curve which was less steep than that for parasites in other groups. Less than 10 organisms survived from the 10(6) parasites exposed to this high dose of irradiation; the possibility exists of obtaining radiation-attenuated P. falciparum.

  13. Food irradiation: Gamma processing facilities

    Kunstadt, P. [MDS Nordion International, 447 March Road. Kanata, Ontario, K2K148 (Canada)

    1997-12-31

    The number of products being radiation processed is constantly increasing and today include such diverse items as medical disposable, fruits and vegetables, bulk spices, meats, sea foods and waste effluents. Not only do the products differ but also many products, even those within the same groupings, require different minimum and maximum radiation doses. These variations create many different requirements in the irradiator design. The design of Cobalt-60 radiation processing facilities is well established for a number of commercial applications. Installations in over 40 countries, with some in operation since the early 1960s, are testimony to the fact that irradiator design, manufacture, installation and operation is a well established technology. However, in order to design gamma irradiators for the preservation of foods one must recognize those parameters typical to the food irradiation process as well as those systems and methods already well established in the food industry. This paper discusses the basic design concepts for gamma food irradiators. They are most efficient when designed to handle a limited product density range at an established dose. Safety of Cobalt-60 transport, safe facility operation principles and the effect of various processing parameters on economics, will also be discussed. (Author)

  14. Elective ilioingunial lymph node irradiation

    Henderson, R.H.; Parsons, J.T.; Morgan, L.; Million, R.R.

    1984-06-01

    Most radiologists accept that modest doses of irradiation (4500-5000 rad/4 1/2-5 weeks) can control subclinical regional lymph node metastases from squamous cell carcinomas of the head and neck and adenocarcinomas of the breast. There have been few reports concerning elective irradiation of the ilioinguinal region. Between October 1964 and March 1980, 91 patients whose primary cancers placed the ilioinguinal lymph nodes at risk received elective irradiation at the University of Florida. Included are patients with cancers of the vulva, penis, urethra, anus and lower anal canal, and cervix or vaginal cancers that involved the distal one-third of the vagina. In 81 patients, both inguinal areas were clinically negative; in 10 patients, one inguinal area was positive and the other negative by clinical examination. The single significant complication was a bilateral femoral neck fracture. The inguinal areas of four patients developed mild to moderate fibrosis. One patient with moderate fibrosis had bilateral mild leg edema that was questionably related to irradiation. Complications were dose-related. The advantages and dis-advantages of elective ilioinguinal node irradiation versus elective inguinal lymph node dissection or no elective treatment are discussed.

  15. Neutron irradiation of seeds 2

    The irradiation of seeds with the fast neutron of research reactors has been hampered by difficulties in accurately measuring dose and in obtaining repeatable and comparable results. Co-ordinated research under an international program organized by the FAO and IAEA has already resulted in significant improvements in methods of exposing seeds in research reactors and in obtaining accurate dosimetry. This has been accomplished by the development of a standard reactor facility for the neutron irradiation of seeds and standard methods for determining fast-neutron dose and the biological response after irradiation. In this program various divisions of the IAEA and the Joint FAO/IAEA Division co-operate with a number of research institutes and reactor centres throughout the world. Results of the preliminary experiments were reported in Technical Reports Series No. 76, ''Neutron Irradiation of Seeds''. This volume contains the proceedings of a meeting of co-operators in the FAO/IAEA Neutron Seed Irradiation Program and other active scientists in this field. The meeting was held in Vienna from 11 to 15 December 1967. Refs, figs and tabs

  16. Food irradiation: Public opinion surveys

    The Canadian government are discussing the legislation, regulations and practical protocol necessary for the commercialization of food irradiation. Food industry marketing, public relations and media expertise will be needed to successfully introduce this new processing choice to retailers and consumers. Consumer research to date including consumer opinion studies and market trials conducted in the Netherlands, United States, South Africa and Canada will be explored for signposts to successful approaches to the introduction of irradiated foods to retailers and consumers. Research has indicated that the terms used to describe irradiation and information designed to reduce consumer fears will be important marketing tools. Marketers will be challenged to promote old foods, which look the same to consumers, in a new light. Simple like or dislike or intention to buy surveys will not be effective tools. Consumer fears must be identified and effectively handled to support a receptive climate for irradiated food products. A cooperative government, industry, health professional, consumer association and retailer effort will be necessary for the successful introduction of irradiated foods into the marketplace. Grocery Products Manufacturers of Canada is a national trade association of more than 150 major companies engaged in the manufacture of food, non-alcoholic beverages and array of other national-brand consumer items sold through retail outlets

  17. Stem cell migration after irradiation

    The survival rate of irradiated rodents could be significantly improved by shielding only the small parts of hemopoietic tissues during the course of irradiation. The populations of circulating stem cells in adult organisms are considered to be of some importance for the homeostasis between the many sites of blood cell formation and for the necessary flexibility of hemopoietic response in the face of fluctuating demands. Pluripotent stem cells are migrating through peripheral blood as has been shown for several mammalian species. Under steady state conditions, the exchange of stem cells between the different sites of blood cell formation appears to be restricted. Their presence in blood and the fact that they are in balance with the extravascular stem cell pool may well be of significance for the surveilance of the integrity of local stem cell populations. Any decrease of stem cell population in blood below a critical size results in the rapid immigration of circulating stem cells in order to restore local stem cell pool size. Blood stem cells are involved in the regeneration after whole-body irradiation if the stem cell population in bone marrows is reduced to less than 10% of the normal state. In the animals subjected to partial-body irradiation, the circulating stem cells appear to be the only source for the repopulation of the heavily irradiated, aplastic sites of hemopoietic organs. (Yamashita, S.)

  18. Food irradiation: Gamma processing facilities

    The number of products being radiation processed is constantly increasing and today include such diverse items as medical disposable, fruits and vegetables, bulk spices, meats, sea foods and waste effluents. Not only do the products differ but also many products, even those within the same groupings, require different minimum and maximum radiation doses. These variations create many different requirements in the irradiator design. The design of Cobalt-60 radiation processing facilities is well established for a number of commercial applications. Installations in over 40 countries, with some in operation since the early 1960s, are testimony to the fact that irradiator design, manufacture, installation and operation is a well established technology. However, in order to design gamma irradiators for the preservation of foods one must recognize those parameters typical to the food irradiation process as well as those systems and methods already well established in the food industry. This paper discusses the basic design concepts for gamma food irradiators. They are most efficient when designed to handle a limited product density range at an established dose. Safety of Cobalt-60 transport, safe facility operation principles and the effect of various processing parameters on economics, will also be discussed. (Author)

  19. Nutritional aspects of food irradiation

    Murray, T.K.

    1981-08-01

    From the nutritional point of view the irradiation of fruits and vegetables presents few problems. It should be noted that irradiation-induced changes in the ..beta..-carotene content of papaya (not available to the Joint Expert Committee in 1976) have been demonstrated to be unimportant. The Joint Expert Committee also noted the need for more data on thiamine loss. These have been forthcoming and indicate that control of insects in rice is possible without serious loss of the vitamin. Experiments with other cereal crops were also positive in this regard. The most important evidence on the nutritional quality of irradiated beef and poultry was the demonstration that they contained no anti-thiamine properties. A point not to be overlooked is the rather serious loss of thiamine when mackerel is irradiated at doses exceeding 3 kGy. Recent evidence indicates that thiamine loss could be reduced by using a high dose rate application process. Though spices contribute little directly to the nutritional quality of the food supply they play an important indirect role. It is thus encouraging that they can be sterilized by irradiation without loss of aroma and taste and without significant loss of ..beta..-carotenes. Of future importance are the observations on single cell protein and protein-fat-carbohydrate mixtures. The reduction of net protein utilization in protein-fat mixtures may be the result of physical interaction of the components.

  20. Thyroid tumors after irradiation; Tumeurs de la thyroide apres irradiation

    Schlumberger, M. [Centre de Lutte Contre le Cancer Gustave-Roussy, 94 - Villejuif (France)

    1995-12-31

    Epidemiological studies have shown an increased incidence of thyroid tumors after external irradiation during childhood. These studies have shown a long latency and have pointed out risk factors, related either to the subject (young age, female sex) or to the radiation (dose, fractionation, protection). Irradiation by Iodine 131 in adulthood does not seen to increase the risk of thyroid tumor but in childhood data are too scarce to allow any conclusion. Similarly, the risks following low radiation doses and/or protected radiation exposure are still matter of debate. (author). 41 refs., 5 tabs., 1 fig.

  1. Currently developing opportunities in food irradiation and modern irradiation facilities

    Wanke, R. [Director Business Development. SteriGenics International Inc. 17901 East Warren Avenue No. 4, Detroit, Michigan 48224-1333 (United States)

    1997-12-31

    I. Factor currently influencing advancing opportunities for food irradiation include: heightened incidence and awareness of food borne illnesses and causes. Concerns about ensuring food safety in international as well as domestic trade. Regulatory actions regarding commonly used fumigants/pesticides e.g. Me Br. II. Modern irradiator design: the SteriGenics {sup M}ini Cell{sup .} A new design for new opportunities. Faster installation of facility. Operationally and space efficient. Provides local {sup o}nsite control{sup .} Red meat: a currently developing opportunity. (Author)

  2. Materials irradiation research in neutron science

    Noda, Kenji; Oyama, Yukio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-11-01

    Materials irradiation researches are planned in Neutron Science Research Program. A materials irradiation facility has been conceived as one of facilities in the concept of Neutron Science Research Center at JAERI. The neutron irradiation field of the facility is characterized by high flux of spallation neutrons with very wide energy range up to several hundred MeV, good accessibility to the irradiation field, good controllability of irradiation conditions, etc. Extensive use of such a materials irradiation facility is expected for fundamental materials irradiation researches and R and D of nuclear energy systems such as accelerator-driven incineration plant for long-lifetime nuclear waste. In this paper, outline concept of the materials irradiation facility, characteristics of the irradiation field, preliminary technical evaluation of target to generate spallation neutrons, and materials researches expected for Neutron Science Research program are described. (author)

  3. Irradiation for conjunctival granulocytic sarcoma

    Fleckenstein, K.; Geinitz, H.; Grosu, A.; Molls, M. [Dept. of Radiation Oncology, Technical Univ. of Munich (Germany); Goetze, K. [Dept. of Hematology and Oncology, Technical Univ. of Munich (Germany); Werner, M. [Dept. of Pathology, Technical Univ. of Munich (Germany)

    2003-03-01

    Case History and Findings: A 73-year-old woman with a history of myeloproliferative syndrome (MPS) presented with bilateral chemosis, redness and burning of the eyes. The ocular motility was severely impaired. Ophthalmological examination revealed markedly distended conjunctivas on both sides. Biopsy disclosed conjunctival granulocytic sarcoma as an initial symptom of acute myelogenous leukemia (AML). Diagnosis was confirmed by peripheral blood smear and bone marrow aspiration. Treatment and Outcome: The orbital tumor disappeared completely after local external beam irradiation with a total dose of 30 Gy and no further orbital recurrence occurred. With chemotherapy following irradiation transient hematological remission was achieved. 5 months after diagnosis the patient died of respiratory failure following atypical pneumonia as a consequence of her underlying disorder. Conclusion: Detection of orbital granulocytic sarcoma, even in the absence of typical leukemic symptoms is of practical importance, because treatment with irradiation can lead to stabilization or improvement in the patient's vision. (orig.)

  4. Irradiation for conjunctival granulocytic sarcoma

    Case History and Findings: A 73-year-old woman with a history of myeloproliferative syndrome (MPS) presented with bilateral chemosis, redness and burning of the eyes. The ocular motility was severely impaired. Ophthalmological examination revealed markedly distended conjunctivas on both sides. Biopsy disclosed conjunctival granulocytic sarcoma as an initial symptom of acute myelogenous leukemia (AML). Diagnosis was confirmed by peripheral blood smear and bone marrow aspiration. Treatment and Outcome: The orbital tumor disappeared completely after local external beam irradiation with a total dose of 30 Gy and no further orbital recurrence occurred. With chemotherapy following irradiation transient hematological remission was achieved. 5 months after diagnosis the patient died of respiratory failure following atypical pneumonia as a consequence of her underlying disorder. Conclusion: Detection of orbital granulocytic sarcoma, even in the absence of typical leukemic symptoms is of practical importance, because treatment with irradiation can lead to stabilization or improvement in the patient's vision. (orig.)

  5. Detection of irradiated frozen foods

    We tried to detect whether foods were irradiated or not by the o-tyrosine method and the mtDNA method. The o-tyrosine method was applied to four kinds of meat (beef, pork, chicken and tuna). The results showed the linear relation between amount of o-tyrosine and dose (0-10 kGy). However, small amount of o-tyrosine were produced in some cases which application of the method summed to be very difficult because small difference between irradiated foods and untreated foods. Possibility of mtDNA method was investigated. Work and time for separation of mitochondria and extraction of DNA were reduced by a protease-solid phase extraction method. By PCR method, accurate mtDNA could be detected from very small amount of DNA. The irradiation effect is able to detect from 50 Gy. (S.Y.)

  6. The identification of irradiated onions

    The aim of this study was to work out a suitable chemical technique for the irradiated onions identification and for the determination of the gamma radiation dose applied. As the average annual 0.30 x 10-4%, it is therefore possible to identify irradiated onions from their higher deoxysaccharide content (0.66 x 10-4%). The deoxysaccharide content (c) in the irradiated onions depends linearly on the applied dose (D) in the range of 0 to 250 Gy according to the equation: D[Gy] = 1.7 x 106 xc[%] - 50. The accuracy of this equation is ± 10%. The detected amount of deoxysaccharides was found to be proportional to the sum of the contents of glucose, saccharose and raffinose. (author)

  7. Mobile gamma-irradiation robot

    A source container with 98 TBq of 137Cs and shielding made from depleted uranium has the total weight of 264 kg, height of 0.370 and diameter 0.272 m is described. The container is joined to accessories allowing movement of the radiation beam. The dose rate at a distance of 0.4 m in the beam axis is 50 Gy/h. Various technical means are available for manipulation and transport. The irradiation process proceeds according to a precalculated program. Safety measures have been taken to secure the possible application of the irradiation plant for the radiopreservation of cultural objects. The licence from health physics authorities has been obtained. The first irradiation process performed is described. (author)

  8. The multifunction neutron irradiator (MNI)

    Yongmao Zhou; Shenzhi Li

    1994-12-31

    The Multifunction Neutron Irradiator (MNI) under design is a small-type neutron source reactor, for studying the Boron Neutron Capture Therapy (BNCT) for human brain glioblastoma and other uses in neutron technology such as Instrumental Neutron Activation Analysis (INAA), short-lived radioistope production, and some fundamental researches. The reactor core is designed to have passive safety and the process control of the reactor operations is fully computerized. There are two operational modes: The routine operation mode with reactor power 20{approximately}30 kW and flux 1 X 10{sup 12} n {center_dot} cm{sup -2} {center_dot} {sup -1} and the enhanced power operation mode for medical irradiation. The irradiator can be located in a medical center, research institute or university.

  9. Nuclear fuel irradiation in ACPR

    Ciocanescu, M.; Negut, G.; Costescu, C.; Georgescu, D.; Pop, I. (Institute for Nuclear Power Reactors, Pitesti (Romania))

    1984-07-01

    For our fuel program, experiments were proposed on CANDU fuel in ACPR in pulsing regimes. These experiments were intended to determine the fuel behavior during large deposition of heat, fuel-clad interaction mechanisms, and failure thresholds. The fuel is 159 mm long, 6.5% enriched UO{sub 2}. The capsule used for irradiation is an atmospheric capsule assembled in the central dry tube. The capsule is 1 m long, 12 cm i.d., and is locked on the lead ballast through a locking device. The fuel is instrumented with three thermocouples (for clad temperature) and a fission gas transducer. The coolant pressure and temperature are also measured. During irradiation, the data are recorded by a high-speed magnetic tape recorder. For the first campaign, three fuel elements will be irradiated. (orig.)

  10. Endodontics and the irradiated patient

    With increasingly larger numbers of irradiated patients in our population, it seems likely that all dentists will eventually be called upon to manage the difficult problems that these patients present. Of utmost concern should be the patient's home care program and the avoidance of osteroradionecrosis. Endodontics and periodontics are the primary areas for preventing or eliminating the infection that threatens osteoradionecrosis. Endodontic treatment must be accomplished with the utmost care and maximum regard for the fragility of the periapical tissues. Pulpally involved teeth should never be left open in an irradiated patient, and extreme care must be taken with the between-visits seal. If one is called upon for preradiation evaluation, routine removal of all molar as well as other compromised teeth should be considered. Attention should be directed to the literature for further advances in the management of irradiated patients

  11. Ionic conductivity in irradiated KCL

    The ionic conductivity of X and gamma irradiated KCL single crystals has been studied between room temperature and 600 degree centigree. the radiation induced damage resulting in a decrease of the conductivity heals by thermal annealing in two steps which are at about 350 and 550 degree centigree respectively. It has been found that the radiation induced colour centres are not involved in the observed decrease of the ionic conductivity. However. It has been observed that the effects of quenching and plastic deformation on the conductivity of the samples are very similar to the effect induced by irradiation. It is suggested that, samples radiation induced dislocation loops might cause the ionic conductivity decrease observed in irradiated samples. (Author)

  12. Endodontics and the irradiated patient

    Cox, F.L.

    1976-11-01

    With increasingly larger numbers of irradiated patients in our population, it seems likely that all dentists will eventually be called upon to manage the difficult problems that these patients present. Of utmost concern should be the patient's home care program and the avoidance of osteroradionecrosis. Endodontics and periodontics are the primary areas for preventing or eliminating the infection that threatens osteoradionecrosis. Endodontic treatment must be accomplished with the utmost care and maximum regard for the fragility of the periapical tissues. Pulpally involved teeth should never be left open in an irradiated patient, and extreme care must be taken with the between-visits seal. If one is called upon for preradiation evaluation, routine removal of all molar as well as other compromised teeth should be considered. Attention should be directed to the literature for further advances in the management of irradiated patients.

  13. Neutron irradiation of beryllium pebbles

    Gelles, D.S.; Ermi, R.M. [Pacific Northwest National Lab., Richland, WA (United States); Tsai, H. [Argonne National Lab., IL (United States)

    1998-03-01

    Seven subcapsules from the FFTF/MOTA 2B irradiation experiment containing 97 or 100% dense sintered beryllium cylindrical specimens in depleted lithium have been opened and the specimens retrieved for postirradiation examination. Irradiation conditions included 370 C to 1.6 {times} 10{sup 22} n/cm{sup 2}, 425 C to 4.8 {times} 10{sup 22} n/cm{sup 2}, and 550 C to 5.0 {times} 10{sup 22} n/cm{sup 2}. TEM specimens contained in these capsules were also retrieved, but many were broken. Density measurements of the cylindrical specimens showed as much as 1.59% swelling following irradiation at 500 C in 100% dense beryllium. Beryllium at 97% density generally gave slightly lower swelling values.

  14. Food irradiation development in Africa

    The paper assesses prospects for using irradiation technology in the preservation of staple foods and in the treatment of agricultural commodities in the African region. This assessment is made in the light of the magnitude of the losses that occur, and the priority attributed by African States to ensuring that foods currently produced are better conserved to reach their consumers in edible condition with minimum loss. Estimates are presented of the cost of food losses and for the consequent food imports necessary to satisfy regional requirements. The principal causes of food loss include bacteria and insect attack, sprouting, maturation and senescence decay. A review of the literature is made which indicates that there is already some limited experience in food irradiation processing in the region. This review and other relevant studies suggest that the major causes of loss in staple foods and deterioration in other agricultural commodities can be controlled or delayed by the application of irradiation doses below the maximum levels permitted by the Codex Alimentarius. In the light of these observations and considering the high estimated cost of food losses and food imports in the region, the paper notes that a systematic assessment of the cost-benefit potential of irradiation processing in the region would be highly desirable. It is advocated that this assessment should determine the feasibility of including irradiation processing as part of the overall technological package required for the preservation of a wide range of foods and cash crops produced in the region. Attention is also drawn to a number of issues to be resolved before commercial-scale operations can be contemplated. These relate to lack of manpower and experience, financial resources and appropriate infrastructure, which may impede a rapid introduction of the technology. In conclusion, details are presented of a co-operative project which is designed to improve national capacities in food

  15. Demonstration of irradiation in onions

    Two onion varietics (Vsetana and Hiberna) were used for the experiments. Radiation treatment was carried out not later than 25 days after harvesting with a 80 Gy dose of gamma radiation. Following treatment the onions were stored at temperatures between 9 and 21.5 degC and a relative humidity of 30 to 76%. Samples were taken at about one month intervals of irradiated and non-irradiated onions of both varieties and the content of deoxysaccharides determined. The concentration in non-irradiated onions was 0.27x10-4% in the Vsetana variety and 0.33x10-4% in the Hiberna variety. In the radiation treated samples the concentrations were higher: 0.65x10-4% in the Vsetana variety and 0.68x10-4% in the Hiberna variety. Samples of the Vsetana variety were further irradiated with doses of 0, 80, 150, 250, 500, 750 and 1000 Gy of gamma radiation and the content of deoxysaccharides determined. It was found that the concentration of deoxysaccharides is in linear dependence on the applied dose, this within the range of 0 to 250 Gy. In this dose range it is possible to determine the absorbed dose from the content of deoxysaccharides. Model solutions were prepared according to the chemical composition of the onions (tabulated). The solutions were irradiated with a dose of 1000 Gy under the same conditions as the onions. The deoxysaccharide concentration in irradiated model solutions was proportional to the concentration of those saccharides which in the solutions were contained in the highest concentration (glucose, saccharose, raffinose). All obtained results are summed up in tables and discussed in great detail. (E.S.) 4 tabs., 1 fig., 29 refs

  16. Regulatory aspects of food irradiation

    The role of the Nuclear Energy Board in relation to radiation safety in Ireland is described. The Board has the duty to control by licence all activities involving ionizing radiation, as well as providing advice and information to the Government on all aspects of radiation safety. The licensing procedures used by the Board, including site approval, construction, commissioning, source loading and commercial operation, in the licensing of large irradiation facilities were described, and an outline of the proposed new legislation which may become necessary if and when the irradiation of food for commercial purposes begins in Ireland is given

  17. Irradiation device for electronic circuits

    The device includes a radiation-tight vessel, a mobile carriage for a radioactive source, a vertically mobile plate carrying a circuit to be tested and an irradiation detector. It includes also a cover related to the vacuum vessel which prevents the source from emitting for a certain source position. It includes also means which prevents irradiation when the vessel is not assembled and which prevents the dismantling when the source is radiating. It includes also a device allowing to disconnect the translation displacement controls of the circuit and of the radiation detector when the source is radiating

  18. Trade promotion of irradiated food

    The meeting carried out by the Group was attended by invited specialists on legislation, marketing, consumer attitudes and industry interested in the application of food irradiation. The major objectives of the meeting were to identify barriers and constraints to trade in irradiated food and to recommend actions to be carried out by the Group to promote trade in such foods. The report of the meeting and selected 9 background papers used at the meeting are presented. A separate abstract was prepared for each of these papers

  19. Irradiated fuel transport emergency arrangements

    For over 30 years spent nuclear fuel has been transported by road and rail. In that time, there has never been an accident involving the release of radioactivity. Notwithstanding this excellent record it is both necessary and desirable to have contingency plans for any emergency situation. The Irradiated Fuel Transport Flask Emergency Plan for England and Wales (IFTFEP) has been developed and administered by Nuclear Electric plc to set out the detailed response by the nuclear industry to a mishap involving an irradiated fuel flask in transit. (author)

  20. Irradiation and annealing sensitivity studies

    This report describes an evaluation of foreign steel production made to US guidelines for improved radiation resistance (new vessel forms) and investigations on radiation sensitivity and post-irradiation annealing for embrittlement relief (vessels produced 1971 or earlier). In the study of foreign steels, investigations coordinated by the IAEA and involving steels produced by West Germany, France, and Japan have confirmed the adequacy of the US-developed specifications. Progress of the Irradiation-Anneal-Reirradiation investigations are described, noting the synergism between copper impurities and nickel alloying in radiation sensitivity and annealing response. The PVI Surveillance Dosimetry Improvement Program, which as primary application to the more radiation sensitive vessels, is also discussed

  1. Irradiated icecreams for immunosuppressed patients

    Vanilla, raspberry, peach and milk jam icecreams were gamma irradiated with 3, 6 and 9 kGy doses in order to achieve microbial decontamination. Microbiological, sensory and some chemical analysis (acidity, peroxides, ultraviolet and visible absorption, thin-layer chromatography and sugar determination) were performed. Water-based icecreams (raspberry and peach) were more resistant to gamma radiation than cream-based ones (vanilla and milk jam). Gamma irradiation with 3 kGy reduced remarkably the microbial load of these icecreams without impairing the quality of the icecreams

  2. Significance of irradiation of blood

    Many reports of fatal GVHD occurring in non-immunocompromised patients after blood transfusion have been published in Japan. One explantation is that transfused lymphocytes were simulated and attack the recipient organs recognized as HLA incompatible. That is so called 'one-way matching'. To reduce the risk of post-transfusion GVHD, one of the most convenient methods is to irradiate the donated blood at an appropriate dose for inactivation of lymphocytes. Because no one knows about the late effect of irradiated blood, it is necessary to make the prospective safety control. (author)

  3. Light ion irradiation creep apparatus

    An experimental technique developed to measure the irradiation creep of metallic specimens subjected to light ion bombardment is described. The experimental apparatus has the capability to remotely set and control ion flux, stress and temperature. Specimen strain is measured continuously with a noncontracting laser extensometer developed for this application. A typical result obtained for the 17 MeV deuteron irradiation of a 0.15 mm (0.006 in.) thick nickel specimen is presented with an analysis of the source and magnitude of both systematic and random errors. (Auth.)

  4. Recent developments in food irradiation

    Nowadays there is growing interest by the food industry, government and consumers in the use of food irradiatin to kill harmful insects, prevent diseases and keep food fresher longer. This interest has been stimulated by growing public concern over chemicals used in foods. While food irradiation technologies have been around for more than 50 years, only recently have they become cost effective and gained prominent attention as potentially safer ways of protecting food products and public health. This paper looks at recent developments in food irradiation processing and discusses the issues that lie ahead. (author)

  5. Irradiation of onions with the commercial potato irradiator

    Three varieties of onion harvested in Hokkaido were irradiated with the Shohoro Potato Irradiator on 29th September, 1981. One ton of each of the varieties, Kitamiki (KI), Ohohtsuku (OH) and Furanui (FU), was used in this investigation. Onions had longer dormancy period in the order of FU>OH>KI. Higher sprouting percentage was obtained in the unirradiated onions, while they were stored at a higher temperature or stored for a longer period. Generally, unirradiated onions sprouted before they were deteriorated. Thus the number of deteriorated bulbs in the unirradiated onions was superficially less than that in the irradiated ones. When the onions which were taken from warehouses on 26th March, 1982 were stored at room temperature, the percentage of wholesome bulbs was higher in KI and OH than FU. Small buds in some of the irradiated onions turned dark after a long storage time. Quantitative estimation of this phenomena is left to be resolved. There was little relationship between the weight loss and the number of wholesome onions. (author)

  6. Chapitre VI. Le Creusot et l’acier Thomas

    Passaqui, Jean-Philippe

    2015-01-01

    Ainsi, quelques années seulement après la création d’un Domaine minier ambitieux, certains des gisements mis en valeur commencent à présenter des signes d’épuisement. Surtout, les innovations dans la métallurgie, la découverte du procédé Thomas notamment, se traduisent par une nouvelle définition de la politique minière et un renouvellement de la place des exploitations au sein de l’entreprise. Les orientations stratégiques qui accompagnent le déclin du Domaine minier posent aussi la question...

  7. Agricultural yields of irradiated sewage sludge

    Lettuce, radish and ryegrass have been used to study the nitrogen fertilization of soil by sewage sludge. The results show that the irradiated sludge improve by 15 - 30 % the production yield, compared to the non-irradiated sludge. (author)

  8. Detection methods for irradiated mites and insects

    Results of the study on the following tests for separation of irradiated pests from untreated ones are reported: (a) test for identification of irradiated mites (Acaridae) based on lack of fecundity of treated females; (b) test for identification of irradiated beetles based on their locomotor activity; (c) test for identification of irradiated pests based on electron spin resonance (ESR) signal derived from treated insects; (d) test for identification of irradiated pests based on changes in the midgut induced by gamma radiation; and (e) test for identification of irradiated pests based on the alterations in total proteins of treated adults. Of these detection methods, only the test based on the pathological changes induced by irradiation in the insect midgut may identify consistently either irradiated larvae or adults. This test is simple and convenient when a rapid processing technique for dehydrating and embedding the midgut is used. (author)

  9. Are low doses of irradiation so dangerous

    Effect of low irradiation doses on the vegetable and animal kingdoms of the Earth inluding mammals and peoples is considered. Comprehensive factual data testifying that low irradiation doses can be useful under certain conditions are given in the generalized form

  10. Safety and quality of irradiated foods

    Irradiated foods can be considered safe concerning pathogenic bacteria decontamination, insect and parasite inactivation, absence of adverse effects to human health. Qualitatively, irradiated foods do not show significant modifications of composition, macro- and micronutrients and of sensory characteristics

  11. Status of irradiation technology development in JMTR

    Irradiation Engineering Section of the Neutron Irradiation and Testing Reactor Center was organized to development the new irradiation technology for the application at JMTR re-operation. The new irradiation engineering building was remodeled from the old RI development building, and was started to use from the end of September, 2008. Advanced in-situ instrumentation technology (high temperature multi-paired thermocouple, ceramic sensor, application of optical measurement), 99Mo production technology by new Mo solution irradiation method, recycling technology on used beryllium reflector, and so on are planned as the development of new irradiation technologies. The development will be also important for the education and training programs through the development of young generation in not only Japan but also Asian counties. In this report, as the status of the development the new irradiation technology, new irradiation engineering building, high temperature multi-paired thermocouple, experiences of optical measurement, recycling technology on used beryllium reflector are introduced. (author)

  12. Food Irradiation Newsletter. V. 14, no. 2

    This issue reports specific training activities on Food Irradiation Process Control School, both for technical supervisors of irradiation facilities and food control officials/inspectors, and summary reports of Workshops on dosimetry techniques for food irradiation and on techno-economic feasibility of food irradiation for Latin American countries are included. After 12 years of operation, the International Facility for Food Irradiation Technology (IFFIT) will cease to function after 31 December 1990. This issue reports the last inter-regional training course organized by IFFIT, and also features reports on food irradiation in Asia. Active developments in the field in several Asian countries may be found in the reports of the Workshop on the Commercialization of Food Irradiation, Shanghai, and the Research Co-ordination Meeting on the Asian Regional Co-operative Project on Food Irradiation (with emphasis on acceptance and process control), Bombay. Status reports of programmes in these countries are also included. Refs and tabs

  13. ICRP N 84: Pregnancy and medical irradiation

    This book is the translation into Spanish of the ICRP n 84: pregnancy and medical irradiation. The diagnosis of pregnancy, irradiation effect in uterus, radiodiagnosis, radiation exposure and recommendations are exposure

  14. Food irradiation with ionizing radiation

    Application possibilities are discussed of ionizing radiation in inhibiting plant germination, in radiopasteurization and radiosterilization of food. Also methods of combining radiation with thermal food sterilization are discussed. The problems of radiation doses and of hygienic purity of irradiated foodstuffs are dealt with. (B.S.)

  15. ESR detection of irradiated seashells

    Raffi, J. [Laboratoire de Recherche sur la Qualite des Aliments, Faculte de Saint-Jerome, Marseille (France); Hasbany, C. [Laboratoire de Recherche sur la Qualite des Aliments, Faculte de Saint-Jerome, Marseille (France)]|[Laboratoire de Chimie des Produits Naturels, Faculte de Saint-Jerome, Marseille (France); Lesgards, G. [Laboratoire de Chimie des Produits Naturels, Faculte de Saint-Jerome, Marseille (France); Ochin, D. [Institut Agricol et Alimentaire de Lille (France). Lab. de Microbiologie et d`Hygiene Alimentaire

    1996-11-01

    Among the protocols for identification of irradiated foodstuffs submitted to the European Committee of Standardization, two using ESR (food containing bone or cellulose) were finally accepted as official `draft European standards` in Berlin on 9-10 June 1994. We present here some new results for oyster and mussel shells, and an ESR draft protocol is proposed. (author).

  16. Operation of the irradiation facilities

    In 1982, 48 companies utilized the 100kCi Co-60 irradiation facility for sterization of their medical products and food products such as gauze sponges, absorbent cotton, ginseng powder and etc. A total of 12,411 cartons of 44 different items of medical products and foods were irradiated for radiosterilization and total operation time was 5,582.3 hours. Source activity of radiosterilization facility was strengthened by supplementing 52,766 Ci Co-60 source. Radiation dosimetry for stationary and dynamic condition in the irradiation cell was done and dose distribution in irradited box was measured after supplement of Co-60 source. Ceric sulfate dosimeter system was used for routine dosimetry in order to guarentee the radiation dose and radiation dosimetry was performed 568 times. In order to develop suitable plastic material for radiosterilization, experiments on the protective effect of hydrocarbon oil on the oxidative degradation of polypropylene were performed. The pre-sterilization counting of contaminated microorganism was carried out on the 6 medical product and the sterility of the irradiated medical product was confirmed accoring to the K.P. IV and U.S.P. XX. (Author)

  17. Manual of food irradiation dosimetry

    Following items are discussed: Fundamentals of dosimetry; description of irradiators; dose distribution in the product and commissioning the process; plant operation and process control; detailed instructions on using various dose-meter systems; references; glossary of some basic terms and concepts

  18. Solar Spectral Irradiance and Climate

    Pilewskie, P.; Woods, T.; Cahalan, R.

    2012-01-01

    Spectrally resolved solar irradiance is recognized as being increasingly important to improving our understanding of the manner in which the Sun influences climate. There is strong empirical evidence linking total solar irradiance to surface temperature trends - even though the Sun has likely made only a small contribution to the last half-century's global temperature anomaly - but the amplitudes cannot be explained by direct solar heating alone. The wavelength and height dependence of solar radiation deposition, for example, ozone absorption in the stratosphere, absorption in the ocean mixed layer, and water vapor absorption in the lower troposphere, contribute to the "top-down" and "bottom-up" mechanisms that have been proposed as possible amplifiers of the solar signal. New observations and models of solar spectral irradiance are needed to study these processes and to quantify their impacts on climate. Some of the most recent observations of solar spectral variability from the mid-ultraviolet to the near-infrared have revealed some unexpected behavior that was not anticipated prior to their measurement, based on an understanding from model reconstructions. The atmospheric response to the observed spectral variability, as quantified in climate model simulations, have revealed similarly surprising and in some cases, conflicting results. This talk will provide an overview on the state of our understanding of the spectrally resolved solar irradiance, its variability over many time scales, potential climate impacts, and finally, a discussion on what is required for improving our understanding of Sun-climate connections, including a look forward to future observations.

  19. Food irradiation: a global scenario

    Many of the foods that will be consumed in the 21st century have not yet been invented. New methods of production need new methods of conservation. Food irradiation by gamma radiation or electron beam is a new technology. The intensive production methods of today lead to several potential dangers. For example - if just one chicken is diseased this bird can contaminate all of one days' production at the slaughter house - on average 300,000 birds per day. One has to have conservation methods that can decontaminate the poultry meat. Irradiation is a method that achieves this. The consumer is becoming more and more sophisticated and demanding with regard to the quality of food products, rejecting chemical additives for example, irradiation is a physical method of conservation, this means that there is no residue left in the product, and that there are no changes in the physical characteristics of the food. This paper examines the use of irradiation technology as a food conservation method in today's industry. (author). 4 refs., 2 tabs

  20. Proton irradiation of bone metastases

    A proton beam with the energy of 100-130 MeV, the range up 6-20 Gy/min and diameter up to 6 cm was used for radio- therapy of mammary gland cancer metastases to the bones adjoining the vital organs or normal tissues with low tolerance (the skull, sternum, ribs, jaw, etc.). Medium fractionation regimens were used for the single doses of 4-10 Gy. The number of fractions was from 1 to 7, the integral dose 17-28 Gy that corresponded to 35-46 Gy of classic fractionation designed by the TDF factor. The first experience of the irradiation of bone metastases has shown that general and local reactions to proton irradiation correspond to a dose delivered and irradiation regimen and do not differ from those in conventional radiation. A marked therapeutic effect was obtained in all the patients. The formation of bigger diameter proton beams and of a deeper range is required for the irradiation of large zones of bone metastases

  1. Ovarian irradiation in recurrent endometriosis

    We describe a case of a young woman with a history of an aplastic anaemia in which pelvic radiotherapy was used successfully in the management of a recurrent and inoperable endometriosis. The use of therapeutic pelvic or ovarian irradiation in endometriosis may be considered, when surgical and medical treatments have been exhausted and have failed. (authors)

  2. Cobalt 60 commercial irradiation facilities

    The advantage of using cobalt 60 for ionizing treatment is that it has excellent penetration. Gamma plants are also very efficient, in as much as there is very little mechanical or electrical equipment in a gamma irradiation facility. The average efficiency of a gamma plant is usually around 95% of all available processing time

  3. Irradiation enhancement of biomass conversion

    The vast supply of cellulosic agricultural residues and industrial by-products that is produced each year is a prospective resource of biomass suitable for conversion to useful products such as feedstock for the chemicals industry and feedstuffs for the livestock industry. Conversions of such biomass is poor at present, and utilization is inefficient, because of physio-chemical barriers to biological degradation and/or anti-quality components such as toxicants that restrict biological usages. Improvements in biodegradability of ligno-cellulosic materials have been accomplished by gamma-ray and electron-beam irradiation at intermediate dosage (approx. 50 Mrad; 0.5 MGy); but applications of the technology have been hampered by questionable interpretations of results. Recent research with organic wastes such as sewage sludge and straw suggests opportunity for important applications of irradiation technology in enhancement of biomass conversion. Data from experiments using irradiated straw as feed for ruminants are presented and discussed in relation to research on prospective usage of sewage products as feed for ruminants. Findings are discussed in regard to prospective applications in industrial fermentation processes. Possible usage of irradiation technology for destruction of toxicants in exotic plants is considered in regard to prospective new feedstuffs. (author)

  4. Secondary limb edemas following irradiation

    Tsyb, A.F.; Bardychev, M.S.; Guseva, L.I.

    1981-09-01

    The results of clinical examination and treatment of 96 patients with secondary limb edemas, developed at late periods after radiation therapy of malignant tumors are discussed. The genesis of edema is accounted both for direct radiation injury of lymphatics and blood vessels (veins) and fibrous changes of tissue in irradiated areas.

  5. Secondary limb edemas following irradiation

    The results of clinical examination and treatment of 96 patients with secondary limb edemas, developed at late periods after radiation therapy of malignant tumors are discussed. The genesis of edema is accounted both for direct radiation injury of lymphatics and blood vessels (veins) and fibrous changes of tissue in irradiated areas. (orig.)

  6. Microstructural processes in irradiated materials

    Byun, Thak Sang; Morgan, Dane; Jiao, Zhijie; Almer, Jonathan; Brown, Donald

    2016-04-01

    These proceedings contain the papers presented at two symposia, the Microstructural Processes in Irradiated Materials (MPIM) and Characterization of Nuclear Reactor Materials and Components with Neutron and Synchrotron Radiation, held in the TMS 2015, 144th Annual Meeting & Exhibition at Walt Disney World, Orlando, Florida, USA on March 15-19, 2015.

  7. Irradiation mucositis and oral flora

    This study, which is motivated by the substantial morbidity of local signs of mucositis and generalized symptoms that result from mucositis induced by therapeutic irradiation, has the following objectives: To investigate if it is possible to prevent irradiation mucositis via oral flora elimination, and, if it is true that flora plays a role in irradiation mucositis, what fraction of the oral flora may be involved; to evaluate oral Gram-negative bacillary carriage; to investigate the possibility to eradicate Gram-negative bacilli from the oral cavity; to evaluate oral yeast carriage; to investigate the possibility to eradicate yeasts stomatitis and the 'selectivity' of elimination of flora. Two methods are described for monitoring alterations of mucositis of the oral cavity and changes in oral flora. Chlorhexidine has been tested as the commonly used prophylaxis. The effect of chlorhexidine 0.1% rinses on oral flora and mucositis has been studied in a prospective placebo controlled double blind randomized programme. The results of the influence of saliva on the antimicrobial activity of chlorhexidine and the results of selective elimination of oral flora in irradiated patients who have head and neck cancer are reported. Salivary inactivation of the topical antimicrobials used for selective elimination of oral flora has been studied and the results are reported. Finally, the objectives that have been achieved (or not) are delineated. The significance of the results of the study are discussed in terms of published information and further lines of research are suggested. (author). 559 refs.; 29 figs.; 20 tabs

  8. Progress in food irradiation: Italy

    The effect of irradiation on the nutritional properties of a number of foodstuffs including potatoes, onions, tomatoes, grapes, dried fruits, carrots, and animal feed is under investigation. The main components investigated are: reducing sugars, total sugars, saccharose, vitamins C and A, niacin, carotenes, free amino acids, total and soluble nitrogen. This research has been the subject of a collaborative work programm. (orig./AJ)

  9. Nutritional aspects of irradiated mangoes

    Mangoes, like most other fruits, constitute a small but very important part of human diet in tropical countries. Their carbohydrate content is a source of energy; however, their main importance is as a rich source of vitamins, particularly vitamins A and C. Increasing the shelf life of mangoes is desirable, since on ripening they become highly perishable and have a very short shelf life. Low-dose irradiation is considered to be a good method for extending their shelf life. This literature review examines the effect of radiation processing on the nutrients in mangoes. In general, irradiation has little effect on the main nutrients, vitamin C, carotenoids and carbohydrates. There is a significant loss of vitamin C only in a few varieties of mangoes, while in the others the vitamin C level is unaffected. The extension of shelf life also depends on the storage conditions, particularly temperature. While low-temperature storage followed by ripening at room temperature leads to high vitamin C levels, it reduces the carotenoid levels in some varieties. Thus, the storage and the ripening temperatures should be optimized for each variety to obtain the maximum benefit of irradiation. Long-term, multi-generation rat feeding studies to assess the wholesomeness of irradiated mangoes have shown no adverse effects

  10. Functional properties of irradiated starch

    Irradiation is an effective method capable of modifying the functional properties of starches. Its effect depends on the specific structural and molecular organization of starch granules from different botanical sources. In this study, we have studied the effect of gamma irradiation (3, 5, 10, 20, 35, 50 kGy) on the rheological properties of some varieties of starch (potato, cassava and wheat). First, we were interested in determining dry matter content; the results showed that the variation in dry matter compared to the control (native starch) is almost zero. So it does not depend on the dose of irradiation. Contrariwise, it differs from a botanical species to another. The viscometer has shown that these starches develop different behaviors during shearing. The native potato starch gave the highest viscosity followed by wheat and cassava which have almost similar viscosities. For all varieties, the viscosity of starch decreases dramatically with an increasing dose of irradiation. At high doses (35 and 50 kGy) the behavior of different starch is similar to that of a viscous pure liquid. The textural analysis via the back-extrusion test showed that increasing the dose of radiation causes a decrease in extrusion force and the energy spent of the different starch throughout the test. Indeed, the extrusion resistance decreases with increasing dose.

  11. Inhomogeneous microstructural growth by irradiation

    Krishan, K.; Singh, Bachu Narain; Leffers, Torben

    In the present paper we discuss the development of heterogeneous microstructure for uniform irradiation conditions. It is shown that microstructural inhomogeneities on a scale of 0.1 μm can develop purely from kinematic considerations because of the basic structure of the rate equations used to d...

  12. Food irradiation: a technology for the eighties

    After a brief review of the physical principles of the process of food irradiation and the biological and chemical effects of radiations, data concerning studies about the wholesomeness of irradiated food are presented. The most important fields of potential industrial applications are described. The technology of food irradiators, the economy, present status and future trends of food irradiation are analyzed, with emphasis on the French example

  13. Irradiation embrittlement and optimisation of annealing

    This conference is composed of 30 papers grouped in 6 sessions related to the following themes: neutron irradiation effects in pressure vessel steels and weldments used in PWR, WWER and BWR nuclear plants; results from surveillance programmes (irradiation induced damage and annealing processes); studies on the influence of variations in irradiation conditions and mechanisms, and modelling; mitigation of irradiation effects, especially through thermal annealing; mechanical test procedures and specimen size effects

  14. Irradiation of poultry meat and its products

    Modern poultry production methods provide many opportunities for microbial contamination, and poultry meat is considered to have a high bacterial load. This document describes means by which poultry meat can be decontaminated, placing especial emphasis on the use of ionizing radiation. Separate chapters describe the irradiation process, methods for detecting whether the food has been irradiated, the wholesomeness of the irradiated products and the regulatory aspects of poultry irradiation. 441 refs, 35 figs, 16 tabs

  15. Irradiance Variations During This Solar Cycle Minimum

    Woods, Thomas N.

    2010-01-01

    The current cycle minimum appears to be deeper and broader than recent cycle minima, and this minimum appears similar to the minima in the early 1900s. With the best-ever solar irradiance measurements from several different satellite instruments, this minimum offers a unique opportunity to advance our understanding of secular (long-term) changes in the solar irradiance. Comparisons of the 2007-2009 irradiance results to the irradiance levels during the previous minimum in 1996 suggest that th...

  16. Irradiation study of industrial glucoamylase preparation

    The changes of properties for industrial glucoamylase preparation (IGP) irradiated by gamma-rays were studied. The experimental results showed that the preservation period because longer and the hygienic quality was improved when the IGP was irradiated by gamma-rays with dose under 2 kGy. The irradiation does not have obvious poor effects on properties of IGP. Therefore the irradiated IGP could be used normally

  17. Effect of irradiation on sweet corn preservation

    60Co γ-ray was used to irradiate newly-harvested sweet corn and the results showed that the effects of irradiation on soluble solids, sucrose, starch and total sugar were not significant. The viscosity of starch decreased with the increasing of irradiation dose. The preservation duration of irradiated sweet corn was 7 days longer than that of CK, and the sweet, smell, taste of sweet corn had no abnormal change

  18. Ultrasonic Transducer Irradiation Test Results

    Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Joe [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Keller, Paul [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hual-Te [Argonne National Lab. (ANL), Argonne, IL (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States); Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States); Rempe, Joy [Rempe and Associates, Idaho Falls, ID (United States)

    2015-02-01

    Ultrasonic technologies offer the potential for high-accuracy and -resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other ongoing efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. For this reason, the Pennsylvania State University (PSU) was awarded an ATR NSUF project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The goal of this research is to characterize and demonstrate magnetostrictive and piezoelectric transducer operation during irradiation, enabling the development of novel radiation-tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, one piezoelectric

  19. Ultrasonic Transducer Irradiation Test Results

    Ultrasonic technologies offer the potential for high-accuracy and -resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other ongoing efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. For this reason, the Pennsylvania State University (PSU) was awarded an ATR NSUF project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The goal of this research is to characterize and demonstrate magnetostrictive and piezoelectric transducer operation during irradiation, enabling the development of novel radiation-tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, one piezoelectric transducer and two

  20. Alopecia after prophylactic cranial irradiation

    Prophylactic cranial irradiation (PCI) is currently widely used in treatment of patients with lung cancer despite that the data on alopecia after PCI are limited. The aim of the study was to identify factors influencing the duration of alopecia after prophylactic cranial irradiation. Two groups of patients were analyzed: group I - 34 patients radically treated for non-small cell lung cancer (NSCLC) and group II - 18 patients undergoing concurrent chemo-radiotherapy for small cell lung cancer (SCLC). In group I 12 patients were treated with radiotherapy only, the remaining patients were treated with neo- or adjuvant chemotherapy (cisplatin + vinorelbine: PN or cisplatin + gemcitabin: PG) in 2 to 6 cycles. PCI was administered during the last tree weeks of thoracic irradiation or . 2 weeks after the last cycle of chemotherapy and consisted of 15 fractions of 2 Gy per day (30 Gy), 5 days per week. Patients from group II received 25 Gy in 10 fractions starting from the second week of thoracic irradiation; chemotherapy (cisplatin + vepesid: PE every 21 days) started concurrently with thoracic irradiation. Alopecia occurred in all patients treated with PCI; hair loss began 2-3 weeks after the initiation of therapy. In group I full re-growth of hair occurred in 33 patients, one patient died during treatment, before hair re-growth had chance to appear. Time to re-growths (TRG) was 1.5-6 months, median 2.5 months. In this group a trend towards longer re-growths in patients who had received more than 3 cycles of chemotherapy (p=0.07). In group II hair re-growths occurred between 5 and 12 months after the completion of treatment, with median time of 10 months, and was significantly longer than in group I. The results suggest that the most important factor for TRG is the type and the number of chemotherapy cycles. (author)

  1. Evaluation of irradiation hardening of proton irradiated stainless steels by nanoindentation

    Yabuuchi, Kiyohiro; Kuribayashi, Yutaka; Nogami, Shuhei; Kasada, Ryuta; Hasegawa, Akira

    2014-03-01

    Ion irradiation experiments are useful for investigating irradiation damage. However, estimating the irradiation hardening of ion-irradiated materials is challenging because of the shallow damage induced region. Therefore, the purpose of this study is to prove usefulness of nanoindentation technique for estimation of irradiation hardening for ion-irradiated materials. SUS316L austenitic stainless steel was used and it was irradiated by 1 MeV H+ ions to a nominal displacement damage of 0.1, 0.3, 1, and 8 dpa at 573 K. The irradiation hardness of the irradiated specimens were measured and analyzed by Nix-Gao model. The indentation size effect was observed in both unirradiated and irradiated specimens. The hardness of the irradiated specimens changed significantly at certain indentation depths. The depth at which the hardness varied indicated that the region deformed by the indenter had reached the boundary between the irradiated and unirradiated regions. The hardness of the irradiated region was proportional to the inverse of the indentation depth in the Nix-Gao plot. The bulk hardness of the irradiated region, H0, estimated by the Nix-Gao plot and Vickers hardness were found to be related to each other, and the relationship could be described by the equation, HV = 0.76H0. Thus, the nanoindentation technique demonstrated in this study is valuable for measuring irradiation hardening in ion-irradiated materials.

  2. Evaluation of irradiation hardening of proton irradiated stainless steels by nanoindentation

    Yabuuchi, Kiyohiro, E-mail: kiyohiro.yabuuchi@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Kuribayashi, Yutaka [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Nogami, Shuhei, E-mail: shuhei.nogami@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan); Kasada, Ryuta, E-mail: r-kasada@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Hasegawa, Akira, E-mail: akira.hasegawa@qse.tohoku.ac.jp [Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki-Aza-Aoba, Aobaku, Sendai, Miyagi 980-8579 (Japan)

    2014-03-15

    Ion irradiation experiments are useful for investigating irradiation damage. However, estimating the irradiation hardening of ion-irradiated materials is challenging because of the shallow damage induced region. Therefore, the purpose of this study is to prove usefulness of nanoindentation technique for estimation of irradiation hardening for ion-irradiated materials. SUS316L austenitic stainless steel was used and it was irradiated by 1 MeV H{sup +} ions to a nominal displacement damage of 0.1, 0.3, 1, and 8 dpa at 573 K. The irradiation hardness of the irradiated specimens were measured and analyzed by Nix–Gao model. The indentation size effect was observed in both unirradiated and irradiated specimens. The hardness of the irradiated specimens changed significantly at certain indentation depths. The depth at which the hardness varied indicated that the region deformed by the indenter had reached the boundary between the irradiated and unirradiated regions. The hardness of the irradiated region was proportional to the inverse of the indentation depth in the Nix–Gao plot. The bulk hardness of the irradiated region, H{sub 0}, estimated by the Nix–Gao plot and Vickers hardness were found to be related to each other, and the relationship could be described by the equation, HV = 0.76H{sub 0}. Thus, the nanoindentation technique demonstrated in this study is valuable for measuring irradiation hardening in ion-irradiated materials.

  3. Evaluation of irradiation hardening of proton irradiated stainless steels by nanoindentation

    Ion irradiation experiments are useful for investigating irradiation damage. However, estimating the irradiation hardening of ion-irradiated materials is challenging because of the shallow damage induced region. Therefore, the purpose of this study is to prove usefulness of nanoindentation technique for estimation of irradiation hardening for ion-irradiated materials. SUS316L austenitic stainless steel was used and it was irradiated by 1 MeV H+ ions to a nominal displacement damage of 0.1, 0.3, 1, and 8 dpa at 573 K. The irradiation hardness of the irradiated specimens were measured and analyzed by Nix–Gao model. The indentation size effect was observed in both unirradiated and irradiated specimens. The hardness of the irradiated specimens changed significantly at certain indentation depths. The depth at which the hardness varied indicated that the region deformed by the indenter had reached the boundary between the irradiated and unirradiated regions. The hardness of the irradiated region was proportional to the inverse of the indentation depth in the Nix–Gao plot. The bulk hardness of the irradiated region, H0, estimated by the Nix–Gao plot and Vickers hardness were found to be related to each other, and the relationship could be described by the equation, HV = 0.76H0. Thus, the nanoindentation technique demonstrated in this study is valuable for measuring irradiation hardening in ion-irradiated materials

  4. National food irradiation programme of Japan

    The present state of studies on feasibility and wholesomeness of irradiated food is presented. Irradiation projects were realized of potatoes, onions, wheat, Vienna sausages, fish-paste products, and mandarine oranges. Mutagenecity tests with Salmonella or E. coli, chromosome aberration tests, dominant lethal tests, fibroblasts and micronucleus tests, and toxicity tests performed in amimals fed with irradiated food showed no positive results

  5. The Financial Analysis of Gamma Irradiation Technology

    The present study discusses the guideline from the economics point of view of the commercial operation optimized for the Egyptian second irradiation facility. This study included four sections about the financial analysis, the analysis of future demand, future supply of commercial application of irradiation and the irradiation price system

  6. Identification of irradiated potatoes by impedance measurements

    A variety of parameters drawn from impedance measurements are tested to distinguish between irradiated and non-irradiated potatoes. Some of these parameters are able to identify the irradiated potatoes. The identification is still possible after a storage time of 3 months. (author)

  7. Biological effects of ultraviolet irradiation on bees

    The influence of natural solar and artificial ultraviolet irradiation on developing bees was studied. Lethal exposures to irradiation at different stages of development were determined. The influence of irradiation on the variability of the morphometric features of bees was revealed. 5 refs., 1 fig

  8. Applications of irradiation to the rubber industry

    Free radicals are created in polymers by irradiation: macroscopic properties of these polymers are then modified by chemical reactions initiated by these radicals. Technological and economical characteristic of irradiation means are recalled, processes used for rubber are described. Specific advantages of irradiation are pointed out and future trends of the technique are forecasted

  9. Evaluating the safety of irradiated foods

    Health agencies throughout the world have evaluated the safety of irradiated foods by considering the likelihood that irradiation would induce radioactivity, produce toxic radiolytic products, destroy nutrients, or change the microbiological profile of organisms in the food. After years of study, researchers have concluded that foods irradiated under the proper conditions will not produce adverse health effects when consumed

  10. Review of current summary of irradiated foods

    The reasons about widely application of food irradiation as a technology for increasing food safety were presenting in this summary. Topics which are discussing are about: purpose of the irradiation, radiological safety, toxicology, microbiological conclusion, alimentary adequacy, packing, labeling, public acceptance, inspection of food irradiated plants

  11. Facts about food irradiation: Controlling the process

    This fact sheet briefly reviews the procedures that exist to control the process of food irradiation. It also summarizes the difficulties in identifying irradiated food, which stem from the fact that irradiation does not physically change the food or cause significant chemical changes in foods. 4 refs

  12. Educative campaign about information on irradiated foods

    The irradiation of foods is accepted by international agencies (FAO, OMS) like a healthy and effective technology at the moment the irradiated foods are marketed easily in many countries, however in other countries exist several factors that affect the practical application of this process. In this work is planned about an educational campaign about the irradiation process directed to the consumers. (Author)

  13. Effect of gamma irradiation on some characteristics of shell eggs and mayonnaise prepared from irradiated eggs

    Shell eggs were irradiated at doses of 0.0, 0,5, 1.0 and 1.5 kGy of gamma irradiation. Immediately after irradiation, microbiological, physical and chemical analyses of eggs and sensory evaluation of mayonnaise prepared from irradiated eggs were done. The results indicated that all doses of gamma irradiation reduced the total counts of mesophilic bacteria and total coli form of yolk eggs. Irradiated eggs with 1.5 kGy maybe suitable microbiologically to prepare safe mayonnaise. There are no significant differences on saturated fatty acids and TBA values between yolk fat extracted from irradiated and that of non-irradiated eggs. Sensory evaluation showed no significant differences between mayonnaise prepared from irradiated and non-irradiated eggs. (Author)

  14. Ultra-micro-electrochemistry under irradiation; Ultramicroelectrochimie sous irradiation

    Perdicakis, M. [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement, UMR 7564 CNRS - Nancy-Univ., 54 - Villers-les-Nancy (France); Corbel, C.; Leoni, E. [Ecole Polytechnique, 91 - Palaiseau (France). Lab. CEA d' Etudes des Solides Irradies; Simon, P. [Centre National de la Recherche Scientifique (CNRS), Centre de Recherches sur les Materiaux a Hautes Temperatures, 45 - Orleans-la-Source (France)

    2007-07-01

    In this work, are exposed volt-amperometric results recorded in situ during irradiation by electrons, protons or helium ions of homogeneous solutions and solid/deionized water interfaces where the solid can be: quartz, steel or uranium oxide. In a second part, the electrochemical answer is obtained in approaching the ultra-micro-electrode in close vicinity to the solid, at a distance inferior to those corresponding to the diffusion layer of this last ones. The last part deals with the results of an experiment which is until now unique: the in situ coupling of ultra-micro-electrochemistry with Raman micro-spectrometry in order to follow the UO{sub 2} corrosion during its irradiation by He{sup 2+} particles. (O.M.)

  15. Pre-pulse irradiation examination, NSRR pulse irradiation and post-pulse irradiation examination of MH-1 fuel rod

    The Nuclear Safety Research Reactor (NSRR) program for studying failure threshold of pre-irradiated LWR fuel under simulated reactivity initiated accident conditions is in progress. In this program a 14 x 14 PWR type fuel K4-1 was segmented from K4/G08 long size PWR rod pre-irradiated in MIHAMA Unit-2 and was pulse irradiated on November 28, 1989 at NSRR. Energy deposition given to the test rod was 60 cal/g·fuel. No failure indication was observed by in-core monitoring and by post-pulse irradiation examination. As one of the NSRR data base on fuel behavior during transient/RIA, data obtained from pre-pulse irradiation examination, during NSRR pulse irradiation, and from post-pulse irradiation examination are summarized. (author)

  16. Pre-pulse irradiation examination, NSRR pulse irradiation and post-pulse irradiation examination of MH-2 fuel rod

    The Nuclear Safety Research Reactor (NSRR) program for studying failure threshold of pre-irradiated LWR fuel under simulated reactivity initiated accident conditions is in progress. In this program, a 14 x 14 PWR type fuel K4-2 was segmented from a K4/G08 long size PWR rod pre-irradiated in MIHAMA Unit-2 and was pulse irradiated on March 8, 1990 at NSRR. Energy deposition given to the test rod was 68 cal/g·fuel. No failure indication was observed by in-core monitoring and by post-pulse irradiation examination. As one of the NSRR data base on fuel behavior during transient/RIA, data obtained from pre-pulse irradiation examination, during NSRR pulse irradiation, and from post-pulse irradiation examination are summarized. (author)

  17. Can food irradiation boost nutrition in China?

    In January 1986, the first of five regional irradiation facilities planned for China opened officially in Shanghai, mainly to process food. Irradiated potatoes, mushrooms, rice, onions, garlic, peanuts, pork sausage, and probably apples, will be introduced in mass marketing trials. Four other demonstration plants for irradiating food are being built near provincial capitals. Food irradiation offers large economic incentives, but transportation is an impediment except near large urban centres. All irradiators, whether mainly for food or not, will be made in China, with the exception of AECL and Swiss participation in two facilities

  18. Carbon nanostructures produced through ion irradiation

    2003-01-01

    Several nanostructures we produced by ion irradiation have been reviewed in this paper. By using ions to irradiate two ultrahigh molecular weight polyethylene targets respectively, it was found that small fullerenes C20 and C26 were grown, adding two members to the fullerene family. Meanwhile, crystalline diamonds also have been produced by Ar+ ions irradiation of graphite. In the experiment of double ions Ni+ and Ar+ irradiation, nanoscale argon bubbles formed. On the other side, when multi-wall carbon nanotubes were irradiated by C+, many MWCNTs evolved to amorphous carbon nanowires and amorphous carbon nanotubes. And there are possible welding in the crossed nanotubes.

  19. Control of food irradiation in Denmark

    In Denmark food irradiation is not allowed. However, with the consideration within EEC about directives regulating food irradiation and the development of methods for detection, it has been found necessary to ascertain that illegally irradiated foods are not found on the Danish market. Irradiation of spices is allowed in many countries even without being declared in the foods. It thus seemed logical to begin the control of food irradiation by screening a number of spices. This resulted in 1992 in the assessment of 105 samples and in 1993 of 48 samples. (author)

  20. The technological evaluation of irradiated wheat flour

    The effect of gamma-irradiation treatments (2.5, 5 and 10 kGy) on some chemical composition, rheological properties and bread quality of the egyptian wheat flour was investigated. At zero time, application of irradiation up to a dose level of 10 kGy did not show any detectable effect on neither protein nor starch percentages, while irradiation led to gradual increase in both water soluble protein and total sugars of treated samples by increasing irradiation dose. During storage at room temperature (25 5 degree C) for 6 months, starch content markedly decreased while water water soluble protein and total sugars increased for both unirradiated and irradiated samples. The farinograph and extensograph readings reflected a better theological properties of the dough made from irradiated flours. There were no differences between the bread characteristics of the irradiated and non-irradiated flour samples. The color of the crust and crumb turned slightly darker and increased with increasing gamma-irradiation doses. There was no effect on odor, taste and freshness due to gamma-irradiation doses whereas, a remarkable improvement in loaf weight and volume had been obtained especially at the highest dose of gamma-irradiation. 4 tabs

  1. Development of data base on food irradiation

    Ito, Hitoshi; Kume, Tamikazu; Hashimoto, Shoji [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Izumi, Fumio

    1995-12-01

    For the exact understanding on food irradiation in Japan, it is important to provide information of food irradiation to consumers, industries and government offices. However, many of information on food irradiation are only restricted in a few experts or institutes relating to this field. For this reason, data base of food irradiation has been completed together with the systems necessary for input the data using computer. In this data base, about 630 data with full reports were inputted in computer in the field of wholesomeness studies, irradiation effects on food, radiation engineering, detection methods of irradiated food and Q and A of food irradiation for easy understanding. Many of these data are inputted by Japanese language. Some English reports on wholesomeness studies are also included which were mainly obtained from international projects of food irradiation. Many of data on food irradiation are responsible in the fields of food science, dietetics, microbiology, radiation biology, molecular biology, medical science, agricultural science, radiation chemistry, radiation engineering and so on. Data base of food irradiation contains many useful data which can apply to many other fields of radiation processing not only on food irradiation but also on sterilization of medical equipments, upgrading of agricultural wastes and others. (author).

  2. Development of data base on food irradiation

    For the exact understanding on food irradiation in Japan, it is important to provide information of food irradiation to consumers, industries and government offices. However, many of information on food irradiation are only restricted in a few experts or institutes relating to this field. For this reason, data base of food irradiation has been completed together with the systems necessary for input the data using computer. In this data base, about 630 data with full reports were inputted in computer in the field of wholesomeness studies, irradiation effects on food, radiation engineering, detection methods of irradiated food and Q and A of food irradiation for easy understanding. Many of these data are inputted by Japanese language. Some English reports on wholesomeness studies are also included which were mainly obtained from international projects of food irradiation. Many of data on food irradiation are responsible in the fields of food science, dietetics, microbiology, radiation biology, molecular biology, medical science, agricultural science, radiation chemistry, radiation engineering and so on. Data base of food irradiation contains many useful data which can apply to many other fields of radiation processing not only on food irradiation but also on sterilization of medical equipments, upgrading of agricultural wastes and others. (author)

  3. Irradiation effects on hydrases for biomedical applications

    Furuta, Masakazu E-mail: mfuruta@riast.osakafu-u.ac.jp; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio

    2000-03-01

    To apply an irradiation technique to sterilize 'Hybrid' biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against {sup 60}Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N{sub 2} gas to suppress the formation of free radicals. (author)

  4. Comparison of Recent Total Irradiance Measurements

    Helizon, R.; Pap, J.

    2002-12-01

    Total solar irradiance has been measured since 1978 from various satellites. Since the absolute accuracy of the current irradiance measurements is about 0.2%, one needs to compile composite irradiance time series to study long-term changes and to establish whether there are any secular variations over the last two and half decades. In this paper we compare the UARS/ACRIM II and SOHO/VIRGO total irradiance data as well as the SOHO/VIRGO and ACRIM III total irradiance. Our main goal is to validate the newly processed ACRIM II total irradiance. Comparison of the SOHO/VIRGO and ACRIM III data will also help to establish whether the high total irradiance values for the maximum of solar cycle 23 represent real solar, rather than, instrumental events.

  5. Rheological and microstructural properties of Irradiated starch

    Gamma irradiation ia s fast and efficient method to improve the functional properties of straches. Wheat and potato starches were submitted, in the present study, at 3,5,10 and 20 kGy radiation dose. The changes induced by irradiation on the rheological properties of these starches showed a decrease in the viscosity with increasing radiation dose. Chemicals bond's hydrolysis has been induced by free radicals that have been identified by EPR. Wheat starch presents five EPR signals after irradiation, whiles potato starch has a weak EPR signal. On the other hand, irradiation caused decrease in amylose content. This decrease is more pronounced in potato starch. Dry irradiated starch's MEB revealed no change in the shape, size and distribution of the granules. While, the observation of wheat starch allowed the complete disappearance of the granular structure and the dissolution of its macromolecules after irradiation which justifies the significant decrease in wheat starch's viscosity irradiated at 20 kGy.

  6. Quality of electron beam irradiated strawberries

    Fresh 'Tristar' strawberries were treated by electron beam irradiation to determine the effects on postharvest quality attributes and shelf life. The intensity of red color rated by sensory panelists decreased as irradiation dosage increased from 0- to 2 kGy. Hunter 'L' values were higher for fruit treated with 2 kGy than for 0 and 0.5 kGy. Instron firmness values were lower for all irradiated fruit than for control fruit. Panelists rated irradiated fruit less firm than nonirradiated fruit stored 1, 2 and 4 days. An increase in off-flavor was noted among all treatments stored 6 and 8 days. Irradiation suppressed fungi on stored berries. Irradiation doses of 1 and 2 kGy extended shelf life 2 and 4 days, respectively. Electron beam irradiation technology has excellent potential for extension of shelf life of fresh strawberry fruits

  7. Food Irradiation Newsletter. V. 11, no. 2

    This issue includes a report of the ICGFI's Workshop on Food Irradiation for Food Control Officials, convened in Budapest, Hungary, May 1987. To provide further assurance on the safety and wholesomeness of irradiated food in general and details about polyploidy (increase in number of chromosomes) resulting from consumption of freshly irradiated wheat in particular, ICGFI Secretariat issued a fact sheet on ''Safety and Wholesomeness of Irradiated Foods: International Status - Facts and Figures'' to its member countries in July 1987. The Newsletter also contains summary reports of two important market testings of irradiated food, i.e. papaya in California in March and strawberries in France in June, which proved that consumers will buy irradiated foods, and status reports on food irradiation in France and Mexico. Ref, 1 tab

  8. Irradiation effects on hydrases for biomedical applications

    Furuta, Masakazu; Ohashi, Isao; Oka, Masahito; Hayashi, Toshio

    2000-03-01

    To apply an irradiation technique to sterilize "Hybrid" biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against 60Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N 2 gas to suppress the formation of free radicals.

  9. Irradiation effects on hydrases for biomedical applications

    To apply an irradiation technique to sterilize 'Hybrid' biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against 60Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N2 gas to suppress the formation of free radicals. (author)

  10. Optical Properties of Irradiated Yttrium Aluminum Garnet

    The results of investigation of the photoluminescence (PL) and optical absorption of crystals Y3Al5O12(YAG) doped with different concentrations of manganese ions exposed to fast neutron irradiation and electron irradiation are presented. Photoluminescence spectra of YAG before neutron irradiation at T=80 K contain fine lines in orange region of spectrum, ascribed to Mn2+ ions in octahedral position. After irradiation band broadening is observed in the luminescence spectra of garnet crystals. Electron irradiation produced broad band with a complex structure related to Mn4+ ions. Exchange interaction between radiation defect and impurity ions during neutron irradiation and electron irradiation leads to appearance of additional lines and luminescence bands broadening in investigated crystals.

  11. Food irradiation development in Pakistan

    Khan, I.

    The large scale trials were held to extend the storage life of potatoes, onions and dry fruits by gamma radiation. It was concluded that radiation preservation of potatoes and onions was much cheaper as compared to conventional methods. A dose of 1 kGy can control the insects in dry fruits and nuts. The consumers' acceptability and market testing performed during the last four years are also conducive to the commercialization of the technology in this country. The Government of Pakistan has accorded clearance for the irradiation of some food items like potatoes, onions, garlic and spices for human consumption. The Pakistan Radiation Services (PARAS), the commercial irradiator (200 Kci) at Lahore, has already started functioning in April, 1987. It is planned to start large scale sterilization of spices by gamma radiation in PARAS shortly.

  12. Human subjects and experimental irradiation

    In recent years the public has expressed concern about the use of human subjects in scientific research. Some professional institutions have adopted codes of practice to guide them in this matter. At the University of New South Wales, where human subjects are used in teaching and research programmes, a committee ensures that high ethical standards are maintained. As the volunteer subjects do not gain any benefit themselves from the procedures, their level of risk is kept low. One type of procedure in which risk is becoming quantifiable, is the irradiation of human subjects. To assist peer review groups, the ICRP, WHO and the National Health and Medical Research Council have enunciated principles which should be followed in the irradiation of human volunteer subjects. In general the role of the Committee is advisory to protect the rights of the investigator, the subject, and the institution. Some of the inherent problems are discussed

  13. Neutron dosimetry for rat irradiations

    Monoenergetic neutron irradiations of rats described in last year's Annual Report (COO-4733-1) were continued in collaboration with the Department of Radiology of Thomas Jefferson University. Three groups of 24 rats received absorbed doses of 0.43 MeV neutrons corresponding to 300, 400, or 560 mGy (30, 40, or 56 rad), respectively, of total tissue kerma in free air at the center of the animal positions. In all cases the absorbed dose contributed by gamma rays was about 3 percent of the total absorbed dose. In order to alleviate some of the traumatic effects of the experimental procedure upon the pregnant rats, extra air holes were drilled in the aluminum end caps of the rat holders, thus providing increased ventilation for respiration and cooling. It was also found to be desirable to postpone transporting them for one day after irradiation

  14. Evaluation of irradiated sewage sludges

    The residual muds are produced by a separation process in the black waters treatment constituted by a solid phase whose origin is the accumulation of pollutant matter that has been extended to the water for anthropogenic and/or natural activities. The present work has the purpose to carry out a technical evaluation for the irradiation process of residual muds for their possible application like alternative of treatment and final disposal. The results obtained for the Evaluation of the irradiation of residual muds are bounded with the federative entities in the study, on the number of treatment plants of residual waters by diverse methods, discharge types, system location, residual muds production and muds treatment, uses and final disposal. The results show in the several entities,a great variety and versatility of industrial branches with diverse systems for treatment of waters and scarceness in the systems for residual muds treatment. (Author)

  15. Genotoxicity test of irradiated foods

    Safety tests of radiation irradiated foods started as early as from 1967 in Japan and genotoxicity tests in the Hatano Res. Inst., from 1977. The latter is unique in the world and is reviewed in this paper. Tests included those for the initial injury of DNA, mutagenicity, chromosomal aberration and transformation with use of bacteria, cultured mammalian cells and animals (for chromosomal aberration, micronucleus formation and dominant lethality). Foods tested hitherto were onion, rice, wheat and flour, Vienna sausage, fish sausage (kamaboko), mandarian orange, potato, black pepper and red capsicum, of which extract or powder was subjected to the test. Irradiation doses and its purposes were 0.15-6 kGy γ-ray (60Co) or electron beam by the accelerator (only for the orange), and suppression of germination, pesticide action or sterilization, respectively. Genotoxicity of all foods under tested conditions is shown negative. (N.I.)

  16. Bone marrow transplantation after irradiation

    Bone marrow transplantation after irradiation is successful in only a part of the affected patients. The Chernobyl accident added to our knowledge: BMT can save life after whole-body irradiation with a dose exceeding 7-8 Gy. A timely decision on transplantation after a nuclear accident is difficult to make (rapid determination of homogeneity and type of radiation and the total dose. HL-A typing in lymphopenia, precise identification of radiation damage to other target organs, etc.). Further attention is to be paid to the treatment. Transplantations in case of malignities (especially hematologic ones) and other diseases will add to our knowledge and will lead to more simple procedures. (author). 3 figs., 1 tab., 12 refs

  17. Kinetics of irradiated liquid hydrogen

    We present a model for the kinetics of irradiated liquid hydrogen, as appropriate to a spallation neutron source environment. This model indicates that the ortho-para distribution in an irradiated volume of liquid hydrogen may be significantly different from the thermodynamically equilibrated distribution, resulting in significantly changed neutronic and operational performance for practical liquid hydrogen moderators. Numerical experimentation with the model indicates that neither the pulsed nature of a pulsed source nor the cyclic nature of a flowing liquid hydrogen loop significantly impacts the ortho-para distribution. In developing this model, we have learned that many proposed methods for measuring the ortho-para distribution in an operating moderator system may have potential difficulties, complicating bench-marking efforts. (orig.)

  18. Maternal irradiation and Down Syndrome

    The role of preconception irradiation in the etiology of Down Syndrome was examined using the techniques of record linkage. Although 909 cases of Down Syndrome, born in B.C. between 1952-70, were ascertained through a system of linked vital and health registrations, interest was restricted to the 348 case/control pairs born in the greater Vancouver area. The maternal identifying information routinely recorded on birth and ill-health registrations was used to link 155 Down Syndrome mothers and 116 control mothers to patient files at the Vancouver General Hospital. Only 28 of the case and 25 of the control mothers were subjected to diagnostic irradiation at the Vancouver Ganeral Hospital. The difference was not significant at the 5% level

  19. Overlay welding irradiated stainless steel

    An overlay technique developed for welding irradiated stainless steel may be important for repair or modification of fusion reactor materials. Helium, present due to n,α reactions, is known to cause cracking using conventional welding methods. Stainless steel impregnated with 3 to 220 appm helium by decay of tritium was used to develop a welding process that could be used for repair. The result was a gas metal arc weld overlay technique with low-heat input and low-penetration into the helium-containing material. Extensive metallurgical and mechanical testing of this technique demonstrated substantial reduction of helium embrittlement damage. The overlay technique was applied to irradiated 304 stainless steel containing 10 appm helium. Surface cracking, present in conventional welds made on the same steel at lower helium concentrations, was eliminated. Underbead cracking, although greater than for tritium charged and aged material, was minimal compared to conventional welding methods

  20. Food Irradiation. Proceedings of the International Symposium on Food Irradiation

    For some years research has been done in several countries, with the object of contributing to the world's food supplies, on the application of nuclear methods to food preservation and processing. The importance of food preservation is of particular relevance in certain regions of the world where up to thirty per cent of harvested foodstuffs are being lost because of damage by animal pests and microorganisms. A series of international meetings have been held on this subject; the first, held in 1958 at Harwell, was followed by further meetings in 1960 in Paris and in 1961 in Brussels. The International Symposium on Food Irradiation organized by the International Atomic Energy Agency and the Food and Agriculture Organization of the United Nations through their Joint Division of Atomic Energy in Agriculture, and held at the Karlsruhe Nuclear Research Centre, Karlsruhe, from 6 to 10 June 1966, at the generous invitation of the Government of the Federal Republic of Germany, is the most recent of this series of meetings. It was held for the purpose of exchanging the most up-to-date results of research, of contributing towards co-operative efforts between Member States, and of stimulating trade in the international exchange of irradiated products between nations. Papers describing research over the past fourteen years were given by outstanding authorities; the results point to a breakthrough having been achieved in the use of ionizing radiation in food preservation, notwithstanding some problems still to be solved, such as overcoming changes in colour, flavour, odour or texture. The Symposium was attended by over 200 scientists from 25 countries and four international organizations. Sixty-nine papers were presented. It was shown that a wide variety of foodstuffs exist for which radiation could be used for three different purposes: to produce indefinitely stable products, to rid food of organisms that constitute health hazards, and to extend the normal shelf or market life

  1. Alterations of ultraviolet irradiated DNA

    Thymine dimers production has been studied in several DNA-3H irradiated at various wave lenght of U.V. Light. The influence of dimers on the hydrodynamic and optic properties, thermal structural stability and transformant capacity of DNA have been studied too. At last the recognition and excision of dimers by the DNA-UV-Endonuclease and DNA-Polimerase-I was also studied. (author)

  2. Wholesomeness data on irradiated food

    There is no item of more primary importance to the welfare of the human race than food. It has long been realized that even small increases in the quality and/or quantity of food mean great benefits to people everywhere, particularly to those who are undernourished or on the threshold of starvation. Therefore, the application of food preservation technology to prevent food losses has become a major factor in solving the world's food problems. Some of the chemical additives used to preserve food have caused harmful effects on the well-being of the consumer, but the newly-developing commercial treatment of a number of food products with low doses of ionizing radiation has been shown to be technologically advantageous and economically viable.The Food Preservation Section of the Joint FA O/lAEA Division decided to set up a data system whereby wholesomeness information on irradiated food can be easily obtained and disseminated by means of publication. The data will be related to toxicological safety, nutritive value and microbial innocuity. To do this the Division has sent a questionnaire to institutes and scientists involved in programmes dealing with wholesomeness of irradiated food, requesting them to provide information on investigations already completed, on those which are currently in progress and on programmes projected for the future. Based on the responses received, a list of wholesomeness investigations recently carried out in Member Countries on different food items, can be found. Summarily it can be stated that the results from these investigations do not indicate any detrimental effects on health. Detailed data will be published periodically by the International Project in the Field of Food Irradiation in 'Food Irradiation Information'. The project has been established under the auspices of FAO, IAEA and OECD (NEA) with 22 countries at present contributing financially to the Project

  3. RERTR-8 Irradiation Summary Report

    D. M. Perez; M. A. Lillo; G. S. Chang; G. A. Roth; N. E. Woolstenhulme; D. M. Wachs

    2011-12-01

    The Reduced Enrichment for Research and Test Reactor (RERTR) experiment RERTR-8, was designed to test monolithic mini-fuel plates fabricated via hot isostatic pressing (HIP), the effect of molybdenum (Mo) content on the monolithic fuel behavior, and the efficiency of ternary additions to dispersion fuel particles on the interaction layer behavior at higher burnup. The following report summarizes the life of the RERTR-8 experiment through end of irradiation, including as-run neutronic analysis, thermal analysis and hydraulic testing results.

  4. Sewage water treatment by irradiation

    Irradiation of the outlet wastewater from Adra Plant shows that radiation sensitivity for the total count of the microorganism, fungi, and pathogenic microorganism were 0.328, 0.327, 0.305 kGy respectively at 3.4 kGy/h. No Ascaris Lumbricoides eggs were found. These results show that radiation technology in wastewater treatment at Adra Plant for reuse in irrigation safely from microbial point of view can be applied. (author)

  5. Pulsed laser irradiation of silicon

    Pulsed laser irradiation of silicon was investigated with a ruby laser. Development of heat flow theory made it possible to calculate temperature profiles in silicon during pulsed laser irradiation. Silicon self-diffusion measurements, laser annealing of damage in As implanted silicon, and laser induced doping of single crystal silicon was investigated. A computer programme was writen based on the numerical solution, and was used to calculate the temperature profiles in silicon during irradiation. Radioactive 31Si was used to determine the self-diffusion of silicon in silicon during irradiation. Radioactivity profiles in the silicon sample were measured by anodic oxidation, sequential removal of the formed SiO2 by etching in dilute HF and measurement of the radioactivity left in the sample. Spreading of the radioactive silicon marker started to take place at energy densities above 0.8 Jcm-2, giving an average duffusion coefficient of (5.0 ± 2.7) x 10-8 m2s-1, which is of the order of magnitude expected when melting takes place. The doping of silicon with Sb, Bi and In by laser assisted diffusion was investegated from evaporated layers as well as solutions of these dopants. The threshold energies for doping was 0.6, 0.9 and 0.7 Jcm-2, while maximum dopant concentrations of 2 x 1021, 7 x 1020 and 4 x 1020 respectively was found for Sb, Bi and In. These values exceed the equilibrium solid solubility by orders of magnitude, and can be ascribed to trapping of the dopant atoms, due to the high recrystallization velocities involved. Doping was carried out by placing silicon substrates directly into solutions of SbCl3 and triphenyl antimony. The threshold of solution doping was found to be much greater than doping from evaporated layer. This difference could be ascribed to the much larger absorption coefficient of the laser light in the evaporated layers, as compared to single crystal silicon

  6. Pulsed laser irradiation of silicon

    Pulsed laser irradiation of silicon was investigated with a ruby laser, having a pulse width of 30 ns and a variable energy up to 1.5 Joules. Peak powers as high as 50 MW are obtained, which is sufficient to cause melting to depths of a few thousand angstroem. In this study, development of heat flow theory made it possible to calculate temperature profiles in silicon during pulsed laser irradiation. Silicon self-diffusion measurements, laser annealing of damage in As implanted silicon, and laser induced doping of single crystal silicon was also investigated. A computer programme was used to calculate the temperature profiles in silicon during pulsed laser irradiation. Radioactive 31Si (half-life = 2.62 hours) was used to determine for the first time the self-diffusion of silicon in silicon during pulsed laser irradiation. Radioactivity profiles in the silicon sample were measured by anodic oxidation, sequential removal of the formed SiO2 by etching in dilute HF and measurement of the radioactivity left in the sample. The removal of damage caused during ion implantation of Si substrates with As was investigated by using laser annealing. Rutherford backscattering of charged nuclear paricles coupled with the channeling technique, showed that an amorphous layer 1140 A thick formed during implantation. Complete removal of this damage only started to take place at energies high enough to cause melting to depths greater than the amorphous/single crystal interface. During resolidification, the molten silicon regrows epitaxially leading to complete removal of all the damage. Disorder removal started at 0.6 Jcm-2, while complete damage removal was achieved at energies above 1.5 Jcm-2. The doping of silicon with Sb, Bi and In by laser assisted diffusion was investigated from evaporated layers as well as solutions of these dopants

  7. Spectroscopic analysis of irradiated erythrocytes

    Selim, Nabila S. [Biophysics Lab, Radiation Physics Department, National Center for Radiation Research and Technology (NCRRT), AEA, P.O. Box 29, Madinat Nasr, Cairo (Egypt); Desouky, Omar S., E-mail: omardesouky@yahoo.com [Biophysics Lab, Radiation Physics Department, National Center for Radiation Research and Technology (NCRRT), AEA, P.O. Box 29, Madinat Nasr, Cairo (Egypt); Ismail, Nagla M.; Dakrory, Amira Z. [Physics Department, Faculty of Girls for Arts, Sciences and Education, Ain Shams University, Cairo (Egypt)

    2011-12-15

    The aim of the present work is to study the effect of gamma radiation on the lipid part of the erythrocyte membrane, and to test the efficiency of lipoic acid as a radioprotector. This effect was evaluated using electron paramagnetic resonance (EPR), and Fourier transform infrared (FT-IR) spectroscopy. The results showed an increase in the number of spin density by 14%, 22% and 65% after exposure to 25, 50 and 100 Gy respectively; whereas there was a decline in the obtained density after incubation with lipoic acid by a factor of approximately 32%. The FT-IR spectra of the irradiated erythrocytes samples showed a marked decrease in the intensity of all characteristic peaks, which increased as the irradiation dose increased. The second-derivative of these spectra, allow the conformationally sensitive membrane acyl chain methylene stretching modes to be separated from the protein (mostly hemoglobin) vibrations that dominate the spectra of intact cells. The 2850 cm{sup -1} band showed changes in the band shape and position after exposure to 50 and 100 Gy. Therefore it can be concluded that the band at 2850 cm{sup -1} only is useful in monitoring the radiation effect of the lipids cell membrane intact cells. - Highlights: > Effect of {gamma} radiation on erythrocyte membrane was studied using EPR and FT-IR. > Efficiency of {alpha}-lipoic acid as radioprotector was tested. > Lipoic acid diminished the free radicals number after gamma irradiation by 32%. > FT-IR spectra of the irradiated erythrocyte showed a decrease in their intensity. > Lipoic acid enhances the membrane to resist the action of gamma radiation.

  8. Stereotactic Irradiation of Lung Cancer

    2000-01-01

    To investigate the best stereotactic irradiation (STI) technique in treatment of small lung tumors, using dose-volume statistics. Methods: Dose-volume histogram (DVH) of the study phantom consisting of CT using the software of FOCUS-3D planning system. The beam was a 6MV X-ray from a Varian 2300C. The analysis data of Dose-volume statistics was from the technique used for: (1) 2- 12 arcs; (2) 20° - 45° separation angle of arcs; (3) 80° - 160° of gantry rotation. Then we studied the difference of DVH with various irradiation techniques and the influence of target positions and field size by calculated to the distribution of dose from 20%- 90% of the six targets in the lung with 3×3 cm2, 4′ 4 cm2 and 5′ 5 cm2 field size. Results: The volume irradiated pulmonary tissue was the smallest using a six non-coplanar 120° arcs with 30° separation between arcs in the hypothetical set up, the non-coplanar SRI was superiority than conventional one's. The six targets were chosen in the right lung, the volume was the largest in geometric center and was decreased in hilus, bottom, anterior chest wall, lateral wall and apex of the lung in such an order. The DVH had significant change with an increasing field size. Conclusion: the irradiation damage of normal pulmonary tissue was the lowest using the six non-coplanar 120° arcs with a 30° separation between arcs by <5×5 cm2 field and the position of target was not a restricting factor.

  9. Food Preservation by Irradiation (Rev.)

    Urrows, Grace M.

    1968-01-01

    Up to 30% of food harvests are lost in some parts of the world because of animal pests and microorganisms. Nuclear techniques can help reduce and extend the shelf life of these foods. Around 55 countries now have food irradiation programs. The use of radiation is the most recent step in man's attempts to preserve some of his harvest for the lean part of the year.

  10. Neutron irradiation of bacteriophage λ

    Double strand breaks (DSB) are the most dangerous lesions in DNA caused by irradiation, but many other lesions, usually called mutations, have not been clearly identified. These lesions, like DSB, can be the source of serious chromosomal damages and finally - cell death. Growing interest in heavy particles for radiotherapy and radioprotection encourages the search of the molecular basis of their action. In this respect, we chose bacteriophage λ1390 as the model system for the study of consequences of neutron irradiation. This derivative of λ phage possesses an unique ability to reversibly reorganize their genome in response to various selective pressures. The phages were irradiated with 13 Gy of mixed neutrons (7.5 Gy from fast and 5.6 Gy from thermal neutrons) and phages genomes were tested to DSB and mutations. Additionally, the stability of λ capsid proteins were tested. After all tests, we can conclude that, under our conditions, low flux of neutrons does not induce neither DNA strand break or DNA mutation nor the stability of λ capsid proteins. (author)

  11. The Techniques Of Food Irradiation

    Food irradiation is a technique which is increasingly being recognised as an effective method for reducing post-harvest food losses, ensuring hygienic quality of food and facilitating wider trade of certain food items. Irradiation of food may be used to achieve a variety of desirable objectives including the following which are classified according to the average radiation dose requirement: i. Low dose application (up to about 1 kg), for inhibition of sprouting in yams, potatoes, onions, etc. insect disinfestation and delay of ripening in fruits. ii. Medium dose applications (about 1-10kgy), for reduction of micro-organisms and improvement in technological properties of food. iii. High dose application (about 10-50kgy) which is used for sterilization for commercial purposes and elimination of viruses. From the point of view of food safety the energy level of the radiation applied to food is the most important characteristics that has to be regulated in order to prevent the possible formation of induced radio activity. Fortunately, the most commonly used isotopic sources 60Co and 137Cs; and machine sources such as the electron beam generators, induced radio activity is negligible, short lived and lower than that causing radio activity. This and other scientific and technical aspects of the commercial application irradiation technology with respect Nigeria have been examined in this paper along side with those of its politics and social policy

  12. Triple ion beam irradiation facility

    A unique ion irradiation facility consisting of three accelerators is described. The accelerators can be operated simultaneously to deliver three ion beams on one target sample. The energy ranges of the ions are 50 to 400 keV, 200 keV to 2.5 MeV, and 1.0 to 5.0 MeV. Three different ions in the appropriate mass range can be simultaneously implanted to the same depth in a target specimen as large as 100 mm2 in area. Typical depth ranges are 0.1 to 1.0 μm. The X-Y profiles of all three ion beams are measured by a system of miniature Faraday cups. The low-voltage accelerator can periodically ramp the ion beam energy during the implantation. Three different types of target chambers are in use at this facility. The triple-beam high-vacuum chamber can hold nine transmission electron microscopy specimens at elevated temperature during a irradiation by the three simultaneous beams. A second high-vacuum chamber on the medium-voltage accelerator beamline houses a low- and high-temperature translator and a two-axis goniometer for ion channeling measurements. The third chamber on the high-energy beamline can be gas-filled for special stressed specimen irradiations. Special applications for the surface modification of materials with this facility are described. Appendixes containing operating procedures are also included. 18 refs., 27 figs., 1 tab

  13. The availability of irradiation data

    NONE

    2004-07-01

    Solar radiation at ground level is a necessary input for performances modeling and sizing of PV systems. This document reports on the needs for data and discusses the problems faced by users when accessing data. It then presents some technological solutions. Users generally need values of global daily or hourly irradiation with a spatial resolution of approximately 10 km. Relative errors (RMSE) of daily irradiation should be less than 20 %. Spatial coverage (continent) and temporal coverage are of importance. The data must be available conveniently at low cost. Several regional solar atlases have been made by interpolation of ground measurements, taking into account the local variation of climate. Satellite data produce irradiation maps offering a regular sampling in space and a wide geographical coverage. Time-series are also obtained by weather forecast models. Digital atlases have been created as integrated information system. These comprise a database and software to exploit it. The co-operative systems are connected with other servers that provide necessary weather data to compute solar radiation quantities. This survey of solar databases showed that in a general case, there is a discrepancy between users needs and available databases. This conclusion supports the efforts made in integrating information systems and co-operative systems to overcome the technical limits of measurements by using the information and communication technologies. (au)

  14. Design of YCF-1 mobile γ irradiator

    YCF-1 mobile irradiator has been designed by Beijing Institute of Nuclear Engineering of China and has been put into use in Jilin province. It can play an important role in extending irradiation technology in food irradiation, disinfestation, sterilization and quarantine. This paper describes the features and design considerations of a mobile irradiator. The irradiator uses a Cesium-137 source, the design loading capacity of the source is 9.25 PBq (250 kCi). The half-life of Cs-137 is 30.2 years and the source does not need replacing. The dose rate on the surface is 0.0025 mSv/h in accordance with national standards. The shielding of the irradiation room is a steel shell filled with lead. The thickness of lead is 18 cm. The irradiator is installed on a special flat truck. The weight of the irradiator is more than 80 tons. The main components and parts of the irradiator are: source, source racks and hoist, irradiation chamber, storage source chamber, the product's transport system, dose monitoring system, ventilation system and safety interlock system. (author)

  15. Low dose irradiation creep of pure nickel

    A detailed climb-controlled glide model of low dose irradiation creep has been developed to rationalize irradiation creep data of pure nickel irradiated in a light ion irradiation creep apparatus. Experimental irradiation creep data were obtained to study the effects of initial microstructure and stress on low dose irradiation creep in pure nickel. Pure nickel specimens (99.992% Ni), with three different microstructures, were irradiated with 17 or 15 MeV deuterons at 473 K and stresses ranging from 0.35 to 0.9 of the unirradiated yield stress. Transmission electron microscopy revealed that the microstructure following irradiation to 0.05 dpa consisted of a high density of small dislocation loops, some small voids and network dislocations. The creep model predicted creep rates proportional to the mobile dislocation density and a comparison of experimental irradiation creep rates as a function of homologous stress revealed a dependence on initial microstructure of the magnitude predicted by the measured dislocation densities. The three microstructures that were irradiated consisted of 85% and 25% cold-worked Ni specimens and well-annealed Ni specimens. A weak stress dependence of irradiation creep was observed in 85% cold-worked Ni in agreement with experimental determinations of the stress dependence of irradiation creep by others. The weak stress dependence was shown to be a consequence of the stress independence of the dislocation climb velocity and the weak stress dependence of the barrier removal process. The irradiation creep rate was observed to be proportional to the applied stress. This linear stress dependence was suggested to be due to the stress dependence of the mobile dislocation density. 101 references, 27 figures, 11 tables

  16. Effect of irradiation on the streptococcus mutans

    To observe direct effect of irradiation on cariogenic Streptococcus mutans. S. mutans GS5 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40 Gy. Viability and changes in antibiotic sensitivity, morphology, transcription of virulence factors, and protein profile of bacterium after irradiation were examined by pour plate, disc diffusion method, Transmission electron microscopy. RT-PCR, and SDS-PAGE, respectively. After irradiation with 10 and 20 Gy, viability of S. mutans was reduced. Further increase in irradiation dose, however, did not affect the viability of the remaining cells of S. mutans. Irradiated S. mutans was found to have become sensitive to antibiotics. In particular, the bacterium irradiated with 40 Gy increased its susceptibility to cefotaxime, penicillin, and tetracycline. Under the transmission electron microscope, number of morphologically abnormal cells was increased as the irradiation dose was increased. S. mutans irradiated with 10 Gy revealed a change in the cell wall and cell membrane. As irradiation dose was increased. a higher number of cells showed thickened cell wall and cell membrane and lysis, and appearance of ghost cells was noticeable. In RT-PCR, no difference was detected in expression of gtfB and spaP between cells with and without irradiation of 40 Gy. In SDS-PAGE, proteins with higher molecular masses were gradually diminished as irradiation dose was increased. These results suggest that irradiation affects the cell integrity of S. mutans, as observed by SDS-PAGE, and as manifested by the change in cell morphology, antibiotic sensitivity, and eventually viability of the bacterium

  17. Development of detection methods for irradiated foods

    To identify irradiated foods, studies have been carried out with electron spin resonance (ESR) spectroscopy on bone containing foods, such as chicken, pork, and beef. The intensity of the signal induced in bones increased linearly with irradiation doses in the range of 1.0 kGy to 5.0 kGy, and it was possible to distinguish between samples given low and high doses of irradiation. The signal stability for 6 weeks made them ideal for the quick and easy identification of irradiated meats. The analysis of DNA damage made on single cells by agarose gel electrophoresis (DNA 'comet assay') can be used to detect irradiated food. All the samples irradiated with over 0.3 kGy were identified to detect post-irradiation by the tail length of their comets. Irradiated samples showed comets with long tails, and the tail length of the comets increased with the dose, while unirradiated samples showed no or very short tails. As a result of the above experiment, the DNA 'comet assay' might be applied to the detection of irradiated grains as a simple, low-cost and rapid screening test. When fats are irradiated, hydrocarbons contained one or two fewer carbon atoms are formed from the parent fatty acids. The major hydrocarbons in irradiated beef, pork and chicken were 1,7-hexadecadiene and 8-heptadecene originating from leic acid. 1,7 hexadecadiene was the highest amount in irradiated beef, pork and chicken. Eight kinds of hydrocarbons were identified from irradiated chicken, among which 1,7-hexadecadiene and 8-heptadecen were detected as major compounds. The concentration of radiation-induced hydrocarbons was relatively constant during 16 weeks

  18. Effect of irradiation on the streptococcus mutans

    Ahn, Ki Dong; Kim, Gyu Tae; Choi, Yong Suk; Hwang, Eui Hwan [Kyung Hee Univ., Seoul (Korea, Republic of)

    2007-03-15

    To observe direct effect of irradiation on cariogenic Streptococcus mutans. S. mutans GS5 was exposed to irradiation with a single absorbed dose of 10, 20, 30, and 40 Gy. Viability and changes in antibiotic sensitivity, morphology, transcription of virulence factors, and protein profile of bacterium after irradiation were examined by pour plate, disc diffusion method, Transmission electron microscopy. RT-PCR, and SDS-PAGE, respectively. After irradiation with 10 and 20 Gy, viability of S. mutans was reduced. Further increase in irradiation dose, however, did not affect the viability of the remaining cells of S. mutans. Irradiated S. mutans was found to have become sensitive to antibiotics. In particular, the bacterium irradiated with 40 Gy increased its susceptibility to cefotaxime, penicillin, and tetracycline. Under the transmission electron microscope, number of morphologically abnormal cells was increased as the irradiation dose was increased. S. mutans irradiated with 10 Gy revealed a change in the cell wall and cell membrane. As irradiation dose was increased. a higher number of cells showed thickened cell wall and cell membrane and lysis, and appearance of ghost cells was noticeable. In RT-PCR, no difference was detected in expression of gtfB and spaP between cells with and without irradiation of 40 Gy. In SDS-PAGE, proteins with higher molecular masses were gradually diminished as irradiation dose was increased. These results suggest that irradiation affects the cell integrity of S. mutans, as observed by SDS-PAGE, and as manifested by the change in cell morphology, antibiotic sensitivity, and eventually viability of the bacterium.

  19. Bakery products from irradiated and non-irradiated eggs - analytical problems associated with the detection of irradiation in processed foods

    In spring and early summer 1992, a number of irradiated egg products were illegally imported into Germay. To prove the irradiation of these egg products, mainly combined gas chromatography-mass spectrometry was applied. With this present study we wanted to answer the question if we were also able to detect the use of irradiated eggs in processed foods. The processed food we chose to produce and to investigate was a tart layer. For this product, dilution effects are of minor importance as no extra fat was added. Thus, the layers' fat almost exclusively came from the eggs. To study the influence of emulsifiers, we produced batters both with and without adding an emulsifer. The unsaturted hydrocarbons C14:1, C16:3, C16:2, C17:2, and C17:1 served as markers for an irradiation. In the non-irradiated egg samples and in the tart layers produced from them, these compounds could not be detected (or in some cases only in small amounts). They were, however, detectable in all irradiated samples. DCB could be found in all irradiated egg samples and in the tart layers that were baked from irradiated eggs. It was not present in non-irradiated eggs and in tart layers produced from them. (orig./Vhe)

  20. High-dose irradiation of food

    Studies performed on behalf of the International Project on Food Irradiation in the period from 1971 until 1980 resulted in the concluding statement that ''.the irradiation of any food commodity up to an overall average dose of 10 kGy presents no toxicological hazard; hence, toxicological testing of foods so treated is no longer required.'' Since then, licenses for food irradiation have been restricted to this maximum dose in any country applying this technology. Further testing programmes have been carried out investigating the wholesomeness or hazards of high-dose irradiation, but there has been little demand so far by the food industry for licensing of high-dose irradiation, as there is only a small range of products whose irradiation at higher doses offers advantages for given, intended use. These include eg. spices, dried herbs, meat products in flexible pouch packagings for astronauts, or patients with immune deficiencies. (orig./CB)

  1. Maintenance of microflora suppression in irradiated monkeys

    After at least two weeks of decontamination, rhesus monkeys were submitted to a total body irradiation of 8.5 Gy, followed by a bone marrow graft. In the following weeks, a number of colonizations were found. Twenty-seven colonizations were known to be present on the day of irradiation. Sixteen colonizations were due to microorganisms suppressed before irradiation. Thirty-two colonizations were considered as exogenous. Only a few colonizations in the irradiated animals could not be controlled. Irradiation caused severe diarrhoea in decontaminated animals, leading to a life-threatening loss of water and electrolytes. When this loss was corrected, the monkeys survived for prolonged periods following irradiation. The amount of food consumed, which contained antibiotics, had no effect on the faecal concentration. The addition of solid food particles, however, resulted in a much lower faecal concentration. No significant antibiotic serum levels were found. (orig.)

  2. Assessing CANDU requirements for irradiation - Research facilities

    The Canadian nuclear program needs ongoing access to irradiation-research facilities to support the safe operation of existing CANDU reactors and the evolutionary development of CANDU components and design features. The irradiation-research program must facilitate the testing of unique CANDU technology such as the fuel bundle, on-power refueling, the pressure tube, and the heavy-water coolant and moderator. Since 1957, NRU has operated as Canada's principal irradiation facility; however, it has become clear that NRU needs costly refurbishing if its lifetime is to be significantly extended. Accordingly, AECL has reviewed the requirements for CANDU irradiation research and is presently assessing alternatives for providing the necessary future access to irradiation-research facilities. Various options are under consideration, including renting space in existing research reactors, performing irradiations in CANDU power reactors, and building a new indigenous materials testing reactor specifically to meet essential program requirements

  3. Irradiation preservation of seafood: Literature review

    The application of gamma-irradiation for extending the shelf life of seafood has been of interest for many years. This report reviews a number of studies on seafood irradiation conducted over the past several years. Topics covered include seafood irradiation techniques and dosages, species applicability and differences, the effects of packaging on seafood preservation, and changes in organoleptic acceptability as a result of irradiation. Particular attention is given to radiation effects (likely and unlikely) of concern to the public. These include the potential for generation of toxic chemical products, botulinum toxin production, and other health concerns. No scientifically defensible evidence of any kind was found for any harmful effect of irradiation of seafoods at the doses being considered (less than 300 krad), and all indications are that irradiation is an acceptable and needed additional tool for seafood preservation. 49 refs., 14 figs., 14 tabs

  4. BR2 Reactor: Irradiation of Fusion Materials

    In collaboration with the EFDA (European Fusion Development Agreement), SCK-CEN irradiates several materials in the BR2 reactor at different temperatures and up to different doses to study their mechanical and physical properties during and after irradiation. Those materials are candidates for the construction of different parts of the ITER fusion reactor and of the long-term DEMO (DEMOnstration) reactor. The objectives of research performed at SCK-CEN are to irradiate up to 2 dpa RAFM (Reduced Activity Ferritic Martensitic) steels joints and RAFM ODS (Oxide Dispersion Strengthening) at 300 degrees Celsius; to build and test an experimental rig to perform in-situ creep-fatigue tests under neutron irradiation and its out-pile equipment and to design a new irradiation basket to irradiate in BR2 copper/stainless steel joints and RAFM specimens with implanted helium at low dose

  5. Irradiation: Technology whose time has come?

    The characteristics and application of food irradiation are briefly discussed, noting FDA's recent approval of the use of this technology to kill trichnella spirals in pork. Despite public concerns, food irradiation sources (gamma rays from Co-60 and Cs-137) are reported to leave no radioactivity in irradiated foods when used under FDA-approved guidelines. Food irradiation was legally ruled to be a 'food additive' by Congress in 1958 with FDA having regulatory authority; however, while low-level dosing has received FDA approval for sprout inhibition in root crops and as an insect control, concerns about cost-effectiveness, safety, and consumer acceptability have continued to limit high dose food irradiation (i.e., exposure to over 1000krad). The future acceptance of food irradiation still, primarily rests in the hands of food service professionals and their consumers

  6. Regeneration of rat thymus after irradiation

    The regeneration processes were investigated in the rat thymus after heavy dose irradiation (6 and 8 Gy). The weight of thymus was gradually recovered to normal level in 6 Gy irradiated thymus, however it recovered only up to 65% of normal level in 8 Gy irradiated thymus. The ED2 positive macrophages were increased on day 3, and then gradually decreased to normal level in 6 Gy irradiated thymus. Inflammatory cytokines (IL-1β, IFN-γ and TNF-α) mRNA expressions were gradually recovered from day 7, however IL-6 mRNA was expressed transiently on day 7 after 8 Gy irradiation. These observations suggest that regeneration processes of irradiated thymus may be intimately regulated by cytokine networks. (author)

  7. The IMO-1 mobile irradiation unit

    The IMO-I is made up by a gamma irradiation bucket and a fixed source, mounted on a trailer specially designed. This equipment has been completed with a radiocomunication device. The irradiator unit consist of two fixed and one movable body. The irradiation bucket has a volume of 30 x 40 x 30 cm and is moved through an hydraulic system with allows its vertical movement between the upper or charging position and the bottom or irradiation position. The telecontrol device has been installed in the room contiguous to the irradiator. The conventional industrial sources of Co60, are vertically located in stainless steel source holders at the botton fixed body and they can be changed according with the desired geometry. The trailer has been built over a plain chassis assembled structure with a double axle at the rear. It consists of two rooms, one for the irradiator machine and the other one for the telecontrol device and the radiocomunication facility. (author)

  8. HRB-22 irradiation phase test data report

    Irradiation capsule HRB-22 was a test capsule containing advanced Japanese fuel for the High Temperature Test Reactor (HTTR). Its function was to obtain fuel performance data at HTTR operating temperatures in an accelerated irradiation environment. The irradiation was performed in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). The capsule was irradiated for 88.8 effective full power days in position RB-3B of the removable beryllium (RB) facility. The maximum fuel compact temperature was maintained at or below the allowable limit of 1300 degrees C for a majority of the irradiation. This report presents the data collected during the irradiation test. Included are test thermocouple and gas flow data, the calculated maximum and volume average temperatures based on the measured graphite temperatures, measured gaseous fission product activity in the purge gas, and associated release rate-to-birth rate (R/B) results. Also included are quality assurance data obtained during the test

  9. Study of irradiation effect on curcuma polyphenols

    The present study was carried out to evaluate the effect of gamma irradiation on curcumin (Curcuma Longa rhizome) component, particularly the polyphenolic fraction. Powdered rhizome was irradiated at 0, 5, 10 and 15 KGy (dose rate of 6 KGy / H). Polyphenolics were extracted and total polyphenols conent (TPC) was quantified using the Folin-Ciocalteau method. The irradiation effect was also evaluated by the HPLC technique. The chromatographic analysis showed that the irradiated and non-irradiated curcumin spectrum gave similar data. The antioxidant and antibacterial activities of the phenolic extracts were also assessed. the anti oxidative potential of the sample was evaluated using two radical scavenging methods with DPPH and ABTS. The antimicrobial analysis showed that the phenolic extracts of curcumin inhibited the growth of the studied microorganisms. Our results showed that irradiated samples were not affected in terms of polyphenols content and characteristics. (Author)

  10. Food Irradiation In Vietnam And Japan

    In 2008, Japan Atomic Energy Commission of Cabinet Office performed the study of current status of food irradiation in the world. The results showed that the total quantity of irradiated foods in 2005 was 405,000 tons. Seven main countries for food irradiation were China, USA, Ukraine, Brazil, South Africa, Vietnam and Japan. In Japan, only the potato irradiation for sprout inhibition is continued more than 35 years since 1974 but the quantity is decreasing. On the other hand, the food irradiation of Vietnam has been developed rapidly in a short time to export the frozen seafood and fruit. This paper shows the status of food irradiation in Vietnam and Japan, and the progress in both countries after 2005. (author)

  11. Food Irradiation Newsletter. Vol. 15, no. 1

    This Newsletter contains reports of the Final FAO/IAEA Research Coordination Meeting (RCM) on the Latin American Regional Cooperative Programme on Food Irradiation, the first FAO/IAEA RCM of the Research Coordination Programme on Analytical Detection Methods for Irradiation Treatment of Foods, and the final FAO/IAEA RCM on the Use of Irradiation as a Quarantine Treatment of Food and Agriculture Commodities. Also included are excerpts of the Seventh Annual Meeting of the International Consultative Group on Food Irradiation (ICGFI) and a summary of an ICGFI Task Force Meeting on Irradiation as a Quarantine Treatment of Fresh Fruits and Vegetables. The new regulations on food irradiation in the United Kingdom, effective 1 January 1991, are summarized

  12. Irradiation of foodstuffs: ECC Report (and debate)

    When the report of the European Communities Committee on the Irradiation of foodstuffs was introduced it was explained that this subject had already been debated and the government had been able to explain and justify the legislation to permit food irradiation. The report notes that, far from being an untested procedure, studies had shown it to be a safe way of treating food. The Committee members had studied all the evidence and visited a food irradiation plant in Holland. The main effects of food irradiation are noted and the reasons for allowing its use are given. The debate lasted nearly two hours and is reported verbatim. The debate covered many aspects of food irradiation: the chemical and nutritional changes in food, the damage to vitamins, the need to mark irradiated food clearly, the lack of an organised data base, food safety and the disposal of packaging materials. (UK)

  13. Irradiation preservation of seafood: Literature review

    Molton, P.M.

    1987-10-01

    The application of gamma-irradiation for extending the shelf life of seafood has been of interest for many years. This report reviews a number of studies on seafood irradiation conducted over the past several years. Topics covered include seafood irradiation techniques and dosages, species applicability and differences, the effects of packaging on seafood preservation, and changes in organoleptic acceptability as a result of irradiation. Particular attention is given to radiation effects (likely and unlikely) of concern to the public. These include the potential for generation of toxic chemical products, botulinum toxin production, and other health concerns. No scientifically defensible evidence of any kind was found for any harmful effect of irradiation of seafoods at the doses being considered (less than 300 krad), and all indications are that irradiation is an acceptable and needed additional tool for seafood preservation. 49 refs., 14 figs., 14 tabs.

  14. Irradiation swelling in self-ion irradiated niobium

    Refractory metals and their alloys offer distinct advantages for applications in nuclear systems where high temperatures are required because they exhibit high elevated temperature strength, better corrosion resistance in liquid alkali metal coolants and better thermophysical properties than other structural materials. One of the important aspects of applications of these materials at high temperatures in irradiation environments is the neutron induced swelling. However, swelling data for these materials are limited and the current theoretical treatments of swelling are not directly applicable to refractory metal since they were developed for face centered cubic (fcc) rather than body centered cubic (bcc) materials. This paper presents initial results of an investigation of swelling mechanisms in a model bcc metal; niobium. The objective of this work is to achieve an understanding of the elevated temperature swelling in bcc metals. A theory-experiment coupling is used to achieve this goal. The neutron induced swelling is simulated by irradiation with self-ions with an accumulated dose corresponding to approx.1 x 1023 n/cm2 (50 displacements per atom, dpa) which exceeds the fluences expected in SP-100

  15. Irradiation Testing of Ultrasonic Transducers

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of numerous parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2 (E> 0.1 MeV). This test will be an instrumented lead test; and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. By characterizing magnetostrictive and piezoelectric transducer survivability during irradiation, test results will enable the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. (authors)

  16. Irradiated food for immunocompromised people

    Immune-compromise is a condition in which the natural defenses against diseases are dimished; several situations can be cited as examples, including mis nourishment, pregnancy, young and old age. This enhances the probability of suffering microbial diseases, caused by food borne pathogens. Traditionally, immune-suppressed patients in hospitals were isolated from the environment, being their food sterilized by different treatments, including irradiation. At present the medical opinion differs from this approach due to the costs and specialized requirements, uncertainties about the clinical benefits, and psychological convenience. So, the tendency nowadays seems to move, when the patient's condition allows it, from 'sterile diets' to 'low microbe diets' (or 'clean diets'). At the National Atomic Energy Commission, Argentina, under Coordinated Research Programmes of the Food and Environmental Preservation Section, International Atomic Energy Agency, in which 14 countries participated, treatments at pasteurizing doses were studied to widen the meals availability for vulnerable persons, to include some products usually considered as 'high risk' , but nutritionally or psychologically adequate. In a first experience, nutritionists working at the corresponding Service in a Buenos Aires hospital elaborated diets suitable for patients with different immune-compromise degrees, and advised on the interesting meal types to be studied. In a second experience, advanced nutrition students of the Entre Rios University performed a sensory evaluation in which 44 immune- compromised patients at the Jose de San Martin Clinical School Hospital, Buenos Aires, tasted a whole irradiated lunch composed of meals usually forbidden due to high microbial risk, though highly desired. The patients evaluated this lunch with high scores and showed enthusiastic towards the irradiation treatment. This preservation treatment could not only be useful to supply hospitals but also supermarkets. (author)

  17. EPR Dosimetry in Irradiated Fingernails

    The Electron Paramagnetic Resonance (EPR) is being transformed in a complementary tool of biologically-based methods for evaluation of dose after accidental radiation exposure. Many efforts are being carried out in laboratories to evaluate the performance of different materials for its use in EPR doses measurements and for improving the current methods for spectrum analysis and calibration curves determinations. In our country the EPR techniques have been used in different areas with dosimetric (alanine) and non dosimetric purposes. Now we are performing the first studies to obtain properly dose response curves to be used for accidental dose assessments through irradiated fingernails. It is by now well known that the fingernails present two types of signals, a background one (BKS), originated in elastic and inelastic mechanical deformations and the radio induced one (RIS), object of interest (I). In this work we will present some of the previous studies performed to characterize the fingernail samples and we analyse the additive dose method for data obtained employing the technique of the substraction of the spectrum recorded at two different microwave powers in order to reduce the BKS signal. Fingernail samples collected from different donors were treated by soaking in water during 10 min and 5 min drying on paper towel and the BKS signals were studied previously its irradiation. The statistical analysis (R statistics) show a distribution with a Standard Deviation of 24% respects to its media. During these studies we also conserved in freezer for more than 6 months irradiated fingernails that, were periodically measured and the statistical analysis of the peak to peak amplitude show a normal distribution through the Quantile correlation test with a SD 11% respected to its median. (authors)

  18. Adriamycin--irradiation cutaneous complications

    Four cases of abnormally severe skin reactions including an instance of skin necrosis occurred in patients with breast cancer who were treated with cyclophosphamide, adriamycin and irradiation concurrently following mastectomy. These unusual skin reactions apparently resulted from the interaction of radiation with adriamycin and prompted us to modify both the radiation dose and the timing of administration of chemotherapy. To date, no unusual or severe skin reactions have been observed in 14 patients who have received chemotherapy with adriamycin plus radiation in accord with this modified treatment plan

  19. Transportation of irradiated fuel elements

    The report falls under the headings: introduction (explaining the special interest of the London Borough of Brent, as forming part of the route for transportation of irradiated fuel elements); nuclear power (with special reference to transport of spent fuel and radioactive wastes); the flask aspect (design, safety regulations, criticisms, tests, etc.); the accident aspect (working manual for rail staff, train formation, responsibility, postulated accident situations); the emergency arrangements aspect; the monitoring aspect (health and safety reports); legislation; contingency plans; radiation - relevant background information. (U.K.)

  20. Reconstruction in previously irradiated patients

    Chaudhari Charudatta

    2007-12-01

    Full Text Available Radiation therapy, which forms the mainstay of the treatment in many head and neck cancers, is viewed by many surgeons with skepticism. But many are not fully conversant with radiobiology and the effect of the radiation in tissues. This article aims at bringing the reader acquainted with the beneficial and harmful effects of radiation on the tissues. The alterations in tissue healing with radiation and the problems associated with surgery in a previously irradiated patient is discussed din detail. The role of free tissue transfer, in this setting is also dealt with.

  1. Thymus irradiation for myasthenia gravis

    Currier, R.D.; Routh, A.; Hickman, B.T.; Douglas, M.A.

    1983-01-01

    Twenty-eight patients with progressive myasthenia gravis without thymoma received treatment of 3000 rads (30 Gy) to the anterior mediastinum, and a followup was conducted for five to 18 years. Twenty-four patients had generalized myasthenia, and four had ocular myasthenia gravis. Twenty patients with generalized myasthenia survived the several month post-treatment period and improved, but four died during that period. The improvement lasted a median of 1.5 years, and older patients had longer remissions than younger patients. The four patients who had ocular myasthenia did not change after treatment. Mediastinal irradiation produces a temporary remission in generalized myasthenia.

  2. Thymus irradiation for myasthenia gravis

    Twenty-eight patients with progressive myasthenia gravis without thymoma received treatment of 3000 rads (30 Gy) to the anterior mediastinum, and a followup was conducted for five to 18 years. Twenty-four patients had generalized myasthenia, and four had ocular myasthenia gravis. Twenty patients with generalized myasthenia survived the several month post-treatment period and improved, but four died during that period. The improvement lasted a median of 1.5 years, and older patients had longer remissions than younger patients. The four patients who had ocular myasthenia did not change after treatment. Mediastinal irradiation produces a temporary remission in generalized myasthenia

  3. Food irradiation and airline catering

    Food poisoning from contaminated airline food can produce serious consequences for airline crew and passengers and can hazard flight. While irradiation of certain foodstuffs has been practised in a number of countries for some years, application of the process has not been made to complete meals. This paper considers the advantages, technical considerations, costs and possible application to airline meals. In addition, the need to educate the public in the advantages of the process in the wake of incidents such as Chernobyl is discussed

  4. Arrangement for selectively irradiating webs

    The arrangement for selectively irradiating a web includes a perforated band of a radiation impermeable substance which is guided in an endless path via a pair of guide rollers and has two juxtaposed runs in this path. A take-up roller conveys a web of material past one of the runs at a side thereof remote from the other run, the direction of movement of the web being other than parallel to that of the band and, preferably, normal thereto. An electron accelerator is provided at the far side of the run remote from the web and is effective for directing a radiation beam at the web through the perforations

  5. Resistance of acrylic vessel to gamma irradiation

    This paper describes the preliminary studies made in acrylic material in order to verify the effects of radiolysis in acrylic recipients in which the uranium ore standards are conditioned and check if the material is able to keep the 222Rn inside the vessel. The preliminary results after gamma irradiation of two kinds of recipients indicate no differences between the vessels irradiated and the ones no irradiated, related to color changes and tension resistance. (author)

  6. Irradiation and the food industry in France

    Part of a special section on food irradiation. The historical development in France of some industrial applications of food irradiation resulting from efficient technology transfer to the food industry is discussed. The 4 basic steps in successfully marketing any technology transfer, including irradiated foods, are that research must define conditions of the product's application, legislation must specify conditions of its application, consumers must accept the product, and appropriate processing capacity must exist

  7. Irradiation as Quarantine Treatment of Rambutan

    Eggs and larvae of Bactrocera dorsalis and Bactrocera correcta were investigated for their tolerant dose of irradiation. Artificially in feasted rambutans were irradiated at target doses of 0, 10, 20, 30, 40, 50 and 60 Gy. The results showed that the lowest dose that could inhibit adult emergence was 102.89 Gy for B. dorsalis and 97.61 Gy for B. correcta (P=0.999968, Probit 9). Larvae of B. dorsalis were irradiated at the dose

  8. Food Irradiation: Microbiological Safety and Disinfestation

    Irradiation can kill microorganisms, insects and parasites and this is a fundamental reason for applying the technology to improve the safety and quality of many foods and food products. This paper will discuss how various organisms can be affected by irradiation treatment. Factors affecting radiation sensitivity will also be discussed and how the use of irradiation in combination with other treatments can be beneficial in improving quality and safety

  9. Models of Solar Irradiance Variations: Current Status

    Natalie A. Krivova; Sami K. Solanki

    2008-03-01

    Regular monitoring of solar irradiance has been carried out since 1978 to show that solar total and spectral irradiance varies at different time scales. Whereas variations on time scales of minutes to hours are due to solar oscillations and granulation, variations on longer time scales are driven by the evolution of the solar surface magnetic field. Here the most recent advances in modelling of solar irradiance variations on time scales longer than a day are briefly reviewed.

  10. Dose rate effect in food irradiation

    It has been suggested that the minor losses of nutrients associated with radiation processing may be further reduced by irradiating foods at the high dose rates generally associated with electron beams from accelerators, rather than at the low dose rates typical of gamma irradiation (e.g. 60Co). This review briefly examines available comparative data on gamma and electron irradiation of foods to evaluate these suggestions. (137 refs., 27 tabs., 11 figs.)

  11. Resistance of acrylic vessel to gamma irradiation

    Carneiro, Andre Cavalcanti; Menezes, Maria Angela de B.C.; Pereira, Marcio Tadeu; Rocha, Nirlando Antonio; Vilela, Jefferson Jose, E-mail: andreccarneiro@gmail.com, E-mail: menezes@cdtn.br, E-mail: mtp@cdtn.br, E-mail: nar@cdtn.br, E-mail: jjv@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Braga, Mario Roberto Martins S.S., E-mail: mariomartins@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2013-07-01

    This paper describes the preliminary studies made in acrylic material in order to verify the effects of radiolysis in acrylic recipients in which the uranium ore standards are conditioned and check if the material is able to keep the {sup 222}Rn inside the vessel. The preliminary results after gamma irradiation of two kinds of recipients indicate no differences between the vessels irradiated and the ones no irradiated, related to color changes and tension resistance. (author)

  12. Application of irradiated chitosan for fruit preservation

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  13. The influence of gamma irradiation in poultry

    The effect of a single whole - body gamma - irradiation of broiler chickens with a dose of 15.0 Gy on the activities of alaninaminotransferase (ALT) and aspartataminotransferase (AST) in the serum was investigated 1, 3, 5 and 7 days post irradiation. The numbers of erythrocytes and leucocytes and concentrations of haemoglobin in peripheral blood was investigated 1, 2, 4, 7, 9 and 14 days post irradiation. (authors)

  14. Food irradiation - a Northern Ireland dimension

    Irradiation is a technology which has been exploited in a wide variety of industries ranging from sterilization of medical products and polymer modification to applications with respect to food. Whilst food irradiation has recently become a controversial subject, the process has been studied for many years. Many products could be irradiated to advantage and these need to be thoroughly investigated before final recommendations can be made as to the commercial feasibility and suitability of the processing technology in the Northern Ireland context

  15. Electron spin resonance identification of irradiated fruits

    The electron spin resonance spectrum of achenes, pips, stalks and stones from irradiated fruits (stawberry, raspberry, red currant, bilberry, apple, pear, fig, french prune, kiwi, water-melon and cherry) always displays, just after γ-treatment, a weak triplet (aH ∼30 G) due to a cellulose radical; its left line (lower field) can be used as an identification test of irradiation, at least for strawberries, raspberries, red currants or bilberries irradiated in order to improve their storage time. (author)

  16. Effectiveness of irradiation in killing pathogens

    United States Environmental Protection Agency regulations include gamma ray irradiation of sludge as an approved Process to Further Reduce Pathogens (PFRP) prior to land application. Research at Sandia National Laboratories on pathogen inactivation in sludge by gamma irradiation has demonstrated that the 1 Mrad PFRP dose is capable, by itself, of eliminating bacterial, fungal, and parasitic pathogens from sludge. Gamma irradiation of sludge in conjunction with the required Processes to Significantly Reduce Pathogens (PSRP) should also eliminate the viral hazard from wastewater sludges

  17. Food irradiation and its biological effects

    Irradiation of foods drew attention mostly in 1960s for disinfestation of food grains, spices and sprout inhibition in mainly potato and onion. γ-irradiation at 0.25 to 1 kGy dosage levels are usually used for irradiating grains, legumes, spices and sprout-prone vegetables. Irradiation of foods with in permissible dosage levels of 0.25 to 5 kGy is usually considered fairly safe from human consumption point of view not withstanding usual health concerns about its usage in foods. Irradiation of foods, in mostly solid or semi-solid form, at 5 kGy levels of γ-irradiation can achieve radicidation or, radiation equivalent of pasteurization and, if γ-irradiation is used at 10 kGy, it can achieve radappertization or, radiation equivalent of thermal commercial sterilization. However, the food industry uses γ-irradiation at 0.25 to 2 kGy only for mostly disinfestation of food grains/legumes, spices, sprout inhibition in potato and onion and, for surface sanitation of frozen fish, poultry and meat. Exposure to irradiation creates free radicals in foods that are capable of destroying some of the spoilage and pathogenic microflora but the same can also damage vitamins and enzymes besides creating some new harmful new chemical species, called unique radiolytic products (URPs), by combining with certain chemicals that a food may be laced with (like pesticides/fungicides). Exposure to high-energy electron beams are also known to create deleterious biological effects which may even lead to detection of trace amounts of radioactivity in the food. Some possible causes delineated for such harmful biological effects of irradiation include: irradiation induced vitamin deficiencies, the inactivity of enzymes in the foods, DNA damage and toxic radiolytic products in the foods. Irradiation, a non-thermal food preservation technique, has a role in salvaging enormous post harvest losses (25-30%) in developing economies to increase the per capita availability of foods. (author)

  18. Effect neutron irradiation on glassy carbon

    Consideration is being given to change of mass (m), volume (v), specific electric resistance (ρ), coefficient of linear thermal expansion (α), dynamic elasticity modulus (E), bending strength (σ) of glassy carbon materials under neutron irradiation. It is shown that neutron irradiation of glassy carbon leads to its shrinkage, accompanied by material disordering. Shrinkage and disordering of glassy carbon decrease with growth both of temperature of material treatment and irradiation temperature

  19. Application of irradiated chitosan for fruit preservation

    Lan, K.N. [Post-harvest Technology Institute, 4, Ngo Quyen-Ha Noi (Viet Nam); Lam, N.D. [Ha Noi Radiation Center, VAEC, 5T-160, Nghiado, Tuliem, Ha Noi (Viet Nam); Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Preliminary test of mango (Mangifera indica) preservation by irradiated chitosan coating has been investigated. The coating by using irradiated chitosan in 1.5% solution has extended the shelf life of mango from 7 to 15 days. At the 15th day mango coated by irradiated chitosan has been keeping good color, natural ripening, without spoilage, weight loss 10%, whereas the mango without coating was spoiled completely and the coating of fruit with unirradiated chitosan inhibited the ripening. (author)

  20. Nutritional value and acceptability of irradiated legumes

    Disinfestation of prepacked cereal products, legumes and pulses by low dose gamma irradiation is well documented. This study showed that irradiation of prepacked green gram (Mung), Bengal gram (Chick pea or Chole) and horse bean (Val) at 0.25 and 0.75 kGy dose did not alter the contents of macronutrients, functional qualities and sensory attributes of these legumes, compared to non-irradiated legumes. (author)