PurposeCataracts are often considered to be an unavoidable consequence of aging. Oxidative damage is a major cause or consequence of cortical and nuclear cataracts, the most common...Full Text Available
The author discusses in detail the following topics: Compensation for domestic nucleardamage and for transfrontier nucleardamage - rule of formal equality of parties which belongs to the basic rule of civil law considering the position of domestic and foreign victims of a grave accident-juridical consequences of the preponderant role played by the state in the promotion, development and supervision of the nuclear industry-rationale for applying the concept of global limitation of liability in the law on nuclear liability and compensation - financial consequences of uncompensated nucleardamage, borne by the victims directly affected or spread over the whole community of the affected state? (HP)
The DNA double-strand break (DSB) damage response induced by high energy charged particles on lung fibroblast cells embedded in a 3-dimensional (3-D) collagen tissue equivalents was investigated using antibodies to the DNA damage response proteins gamma-histone 2AX (#gamma#-H2AX) and phosphorylated DNA-PKcs (p-DNA-PKcs). 3-D tissue equivalents were irradiated in positions across the linear distribution of the Bragg curve profiles of 307.7 MeV/nucleon, 556.9 MeV/nucleon, or 967.0 MeV/nucleon "5"6Fe ions at a dose of 0.30 Gy. Patterns of discrete DNA damage streaks across nuclei or saturated nucleardamage were observed, with saturated nucleardamage being more predominant as samples were positioned closer to the physical Bragg peak. Quantification of the DNA damage signal intensities at each distance for each of the ...
Displacements per atom (DPA) is a widely used damage unit for displacement damage in nuclear materials. Calculating the DPA for SiC irradiated in a particular facility requires a knowledge of the neutron spectrum as well as specific information about displacement damage in that material. In recent years significant improvements in displacement damage information for SiC have been generated, especially the energy required to displace an atom in an irradiation event and the models used to describe electronic and nuclear stopping. Using this information, numerical solutions for the displacement functions in SiC have been determined from coupled integro-differential equations for displacements in polyatomic materials and applied in calculations of spectral-averaged displacement cross sections for SiC. This procedure has been used to generate spectrally averaged ...
Displacements per atom (DPA) is a widely used damage unit for displacement damage in nuclear materials. Calculating the DPA for SiC irradiated in a particular facility requires a knowledge of the neutron spectrum as well as specific information about displacement damage in that material. In recent years significant improvements in displacement damage information for SiC have been generated, especially the energy required to displace an atom in an irradiation event and the models used to describe electronic and nuclear stopping. Using this information, numerical solutions for the displacement functions in SiC have been determined from coupled integro-differential equations for displacements in polyatomic materials and applied in calculations of spectral-averaged displacement cross sections for SiC. This procedure has been used to generate spectrally averaged ...
This paper dealt with the identification of possible damaging mechanism of the collector of the WWER 440 steam generator, cracking of primary collectors, corrosion damage of the protective coat of the primary collector circumferential weld, cracking of breathing space in the region of blinding effect by corrosion and strain, leaking of disassembling joint of the primary collector lid and with the integrity of heat exchanging tubes.
Possible causes of forest damage are discussed. Mapping of affected areas by various workers resulted in dissimilar pictures. Release of radioactive rare gases, aerosols, tritium and carbon-14 seems unlikely to have a significant influence on forest damage. Influence of radioactive fallout, ozone formation by high-voltage transmission lines and synergistic effects is also found to be negligible.
The German National Group of the International Nuclear Law Association, AIDN/INLA, held its 10{sup th} regional conference in Celle on September 2 and 3, 2004. The event was attended by approx. 120 participants from twenty countries discussing 'the Internationalization of Nuclear Law'. Four sessions were devoted to in-depth studies of these topics: - Legal problems associated with the management of radioactive waste. - Regional nuclear safety vs. global nuclear safety. Do the Europeans need a supplementary EU regime of nuclear safety? - Liability and insurance in cases of nucleardamage. - Topical issues of German nuclear law. (orig.)
Cocaine is a worldwide used drug and its abuse is associated with physical, psychiatric and social problems. The mechanism by which cocaine causes neurological damage is very complex and involves several...Full Text Available
Accurate calculations of atomic displacement damage in materials exposed to neutrons require detailed spectra for primary recoil nuclei. Such data are not available from direct experimental measurements. Moreover, they cannot always be computed accurately starting from evaluated nuclear data libraries such as ENDF/B-V that were developed primarily for neutron transport applications, because these libraries lack detailed energy-and-angle distributions for outgoing charged particles. Fortunately, a new generation of nuclear model codes is now available that can be used to fill in the missing spectra. One example is the preequilibrium statistical-model code GNASH. For heating and damage applications, a supplementary code called RECOIL has been developed. RECOIL uses detailed reaction data from GNASH, together with angular distributions based on Kalbach-Mann systematics to compute the energy and angle ...
The paper discusses the role of the Life Management Programme in ensuring a safe operation of the Dukovany nuclear power plant. The Programme involves the following major items: (i) primary circuit materials degradation assessment, (ii) pipeline damage control by the Flow Assisted Corrosion Monitoring and Prediction Programme, and (iii) the DIALIFE diagnostic system. (author)
The objectives of the research in the field of epidemiology , performed at the Belgian Nuclear Research Centre SCK-CEN are (1) to study cancer mortality and morbidity in nuclear workers in Belgium; (2) to document the feasibility of retrospective cohort studies in Belgium; (3) to participate in the IARC study. For radiobiology, the main objectives are: (1) to elucidate the mechanisms of the effects of ionizing radiation on the mammalian embryo during the early phase of its development, (2) to assess the genetic risks of maternal exposure to ionizing radiation, (3) to elucidate the mechanisms by which damage to the brain and mental retardation are caused in man after prenatal irradiation. The main achievements in these domains for 1997 are presented.
The analysis for priority rankings of the recommendations to reduce the total core damage frequency (CDF) of Wolsong nuclear power plant units 2/3/4 was performed in this paper. In order to derive the recommendations, the sensitivity analysis of CDF on which major contributors effect was performed based on the accident quantification results during Level 1 probabilistic safety assessments (PSA). Priorities were ranked in the way that compares the CDF reduction rate with the efforts required to implement those recommendations using risk matrix.
Imatran Voima Oy , (IVO) operates two Russian designed nuclear power plants of type VVER440/213. Unit 1 has been operating since 1977 and unit 2 since 1981. First damage of feed water distribution (FWD) pipes was observed in 1989. In closer examinations FWD-pipe T-connection and distribution nozzles suffered from severe erosion corrosion damage. Similar damages have been found also in other VVER-440 type NPPs. In 1994 the first FWD-pipe was replaced by a new design mounted over the tube bundle instead of the old FWD-pipe, which was located inside the tube bundle. The purpose of this paper is to describe the new FWD-pipe and discuss its effects on the steam generator chemistry. (author)
Modelling the behaviour of fission product (FP) in a nuclear reactor coolant system (RCS) undergoing a hypothetical severe accident is an important step in the evaluation of radioactive release outside a nuclear power plant. This paper scrutinize Small Break LOCA sequence for WWER1000 reactor in order to investigate the possible paths for release of FP from fuel pallets to the reactor containment. Contemporaneous computer code for simulation of RCS will be use for the analysis. The results from analysis of fuel damage and release of FP trough the break of cold leg are present. (author)
Iodine deficiency disorders (IDD) are one of most common nutritional deficiencies in the world. The nuclear analytical methods (ENAA, SRXRF and XRF) were employed to study the effect of iodine deficiency on the metal ion changes during the stage of brain development, combined with biochemical methods. The results show that the distributions of iron, copper and zinc varied to different extent in different brain regions and subcellular fractions of the ID rat brains. These distributional changes of trace elements might be associated with the brain damage caused by the iodine deficiency. (author)
The study required by the West German Ministry of Research and Technology (RS 605) for the Committee on 'Future Nuclear Energy Policy' of the 9th German Parliament is concerned with the following main points: 1) Assessment of technical risks from the social aspect; 2) Discussion of terms and quantification of risks; 3) 'Engineering judgment' and 'questionable' methods in the Fast Breeder analysis of the Society for Reactor Safety (GRS); 4) Assessment criteria of potential damage. (HP).
The volume contains reports on plant technology, on systems organisation with the aim to minimize the risk (human error), on the problem of seismic risk, on core-disruptive accidents and on accident consequence models with different release categories and a comparison of the potential damage incurred. Mr. Webb; one of the authors, attempts to disprove the objections to his two earliest SNR statements by experts of Karlsruhe Nuclear Research Centre.
The volume contains reports on plant technology, on systems organisation with the aim to minimize the risk (human error), on the problem of seismic risk, on core-disruptive accidents and on accident consequence models with different release categories and a comparison of the potential damage incurred. Mr. Webb; one of the authors, attempts to disprove the objections to his two earliest SNR statements by experts of Karlsruhe Nuclear Research Centre. (AK).
The seawater in the intake structure flows into the large pump to with draw excess heat from the turbine steam condenser. In the intake structure of a nuclear power plant, undesirable pump operating characteristics such as vortices, impeller damages and non-uniform pump-approach flow around the pump bells take place frequently due to poorly-arranged intake geometry. In this study, physical modeling test was performed to predict the hydraulic phenomenon, and proposed flow control devices.
With the Government decision to phase out the Fast Reactor at Dounreay there is a need to find alternative employment in the area. Traditionally Caithness is an area of farming, fishing and tourism which could be damaged if Dounreay were to be made a nuclear waste repository. The suggestion is that Dounreay should become a centre for research, development and subsequent manufacture of renewable energy sources and devices to harness renewable energy. The Scottish coastline has potential for wind and wave power developments and this could lead to a whole industry in the future. (UK).
In spite of extensive cooling water studies premature damage due to corrosion occurred on the CuZn20Al condenser tubes. It was then decided to incorporate new titanium-tubed condensers during the annual overhauls of 1983 and 1985 and also take ameliorating measures up to the exchange of individual condensers. (orig.).
The transmutation of minor actinides in-reactor is one solution currently being studied for the long time management of nuclear waste. In the heterogeneous concept the radionuclides are incorporating in an inert ceramic matrix. The support material must be insensitive to radiation damage. Fission product damage is the main radiation damage source during the transmutation process and therefore it is of the utmost importance to study their effects. We irradiated spinels MgAl_2O_4 (matrix of reference) and ZnAl_2O_4 by fast ions (by example: (86)Kr of approximately 400 MeV) simulating the fission products. Under these conditions, the damage is primarily due to the electronic energy losses (Se). One of the structural features of spinel AB_2O_4 is that the two cations (A(2+) and B(3+)) can exchange their site. This phenomenon is quantified by the inversion parameter. We highlight by XRD ...
The phenomena and effects of airblast, ground shock, thermal radiation, cratering and ejecta, and debris cloud and deposition from the eruption of Mt. St. Helens were compared to those that would result from a nuclear explosion to determine if phenomena or effects were analogous and thus might provide useful data for military nuclear weapon effects studies. It is concluded that the phenomena are not analogous. In particular, airblast destruction was caused by clouds of ash driven by subsonic winds, rather than by a supersonic shock wave that would be the damage mechanism of a nuclear explosion. Because of the lack of analogy between the eruption and nuclear explosion phenomena, it appears questionable that any of the effects are analogous; therefore, it is unlikely that anything more of military interest can be gained from studying the effects of the eruption. However, key contacts ...
As part of the Nondestructive Evaluation Reliability Program sponsored by the US Nuclear Regulatory Commission, the Pacific Northwest Laboratory is developing a method that uses risk-based approaches to establish in-service inspection plans for nuclear power plant components. This method uses probabilistic risk assessment (PRA) results and Failure Modes and Effects Analysis (FEMA) techniques to identify and prioritize the most risk-important systems and components for inspection. The Surry Nuclear Power Station Unit 1 was selected for pilot applications of this method. The specific systems addressed in this report are the reactor pressure vessel, the reactor coolant, the low-pressure injection, and the auxiliary feedwater. The results provide a risk-based ranking of components within these systems and relate the target risk to target failure probability values for individual components. These results will be used to guide ...
Nowadays the safety of Nuclear Power Plants is becoming more and more significant. Therefore consideration of severe accidents shall be included in both design and operating process of Nuclear Power Plants. In particular ground motion forms one of the important natural hazards. For structural analysis both linear-elastic and non-linear methods are specified by the engineering codes for earthquake resistance design. However, time history analysis is required for investigation of non-linear structural behaviour. Moreover, non-linearities are often caused by the presence of damage. This can be detected by means of structural health monitoring and subsequently system identification. In this paper the advantages of both dynamic time history analysis and damage detection by means of wavelet analysis are discussed. First, the non-linear behaviour of a frame structure due to an artificial earthquake motion is ...
Recent research findings of epidemiologist Alice Stewart suggest that nuclear workers may be at risk of contracting cancer even though their measured occupational doses fall within current safety standards. It is argued that these standards are inappropriate as they are based on extrapolations of studies on survivors of the Hiroshima and Nagasaki explosions. These individuals received single doses of radiation, whereas today's nuclear industry personnel are exposed to low-level ionizing radiation over the length of their working lives. Stewart's team linked low dose occupational exposure to ionizing radiation with an increased risk of cancer in respiratory, digestive and blood-forming tissues. The nuclear industry and United States government agencies hotly contest these assertion with their potentially damaging political and economic consequences. (UK).
Recent research findings of epidemiologist Alice Stewart suggest that nuclear workers may be at risk of contracting cancer even though their measured occupational doses fall within current safety standards. It is argued that these standards are inappropriate as they are based on extrapolations of studies on survivors of the Hiroshima and Nagasaki explosions. These individuals received single doses of radiation, whereas today's nuclear industry personnel are exposed to low-level ionizing radiation over the length of their working lives. Stewart's team linked low dose occupational exposure to ionizing radiation with an increased risk of cancer in respiratory, digestive and blood-forming tissues. The nuclear industry and United States government agencies hotly contest these assertion with their potentially damaging political and economic consequences. (UK).
The possible corrosion damage is discussed of the CrNi and CrNiMo types steels used as structural materials in WWER type nuclear power plants. It includes point and slot corrosion, corrosion cracking and corrosion fatigue as well as corrosion denting. Also discussed are test procedures that simulate operating conditions and are used for assessing the properties of metallurgical products (sheets and tubes) used in nuclear power engineering. Briefly described is a system for testing the said products in an aqueous medium while keeping the test parameters in a narrow range for a long time. Under the defined temperature, pressure and corrosion medium composition, the test specimens in this system can mechanically be loaded, both statically and dynamically or a temperature gradient can be produced at the tube-tube plate joint. (Z.M.). 1 fig., 1 tab., 10 refs.
The SCDAP computer code, which is being developed under the sponsorship of the United States Nuclear Regulatory Commission, models the progression of light water reactor core damage including core heatup, core disruption and debris formation, debris heatup, and debris melting. SCDAP is being used to help identify and understand the phenomena that control core behavior during a severe accident, to help quantify uncertainties in risk assessment analysis, and to support planning and interpretation of severe fuel damage experiments and data. Comparisons between SCDAP calculations and the experimental data showed good agreement. Calculated and measured bundle temperatures for SFD-ST were within 200 K for the entire bundle and within 20 K for maximum cladding temperatures. For ESSI-2, calculated and measured maximum cladding temperatures were within 50 K, and the extensive liquefaction and relocation that was calculated was in ...
Anti-reflective coatings made with Teflon AF2400 had the highest damage thresholds recorded for physical vapor deposited coatings at the Lawrence Livermore National Laboratory damage facility. Physical vapor deposited layers of Teflon AF2400, a perfluorinated amorphous polymer, maintained the bulk optical properties of a high transmittance from 200 nm to 1600 nm, and a low refractive index. In addition, the refractive index can be intentionally reduced by control of two common deposition parameters, deposition rate and substrate temperature. Scanning electron microscopy and nuclear magnetic resonance observations indicated that morphological changes caused the variations in the refractive index rather than compositional changes. The coatings adhered to fused silica and silicon wafers under normal laboratory handling conditions.
Steam generators (SG) are the weak link of nuclear power plants, their service life is shorter than the service life of other NPP components. This paper is dedicated to a statistical analysis of SG damages and failures. Heat exchanging tubes (HET) are the most damaged elements in SG, there are on average 286 plugged or repaired tubes in each operating SG. The usually mechanisms of tube failure are the following: denting, corrosion at tube outside, pitting, fretting, and circular crack propagation. Most of damages are located in the transition zone above a tube plate. This study shows that the factors that are involved in the SG HET fault probability are: - design features of SG and secondary equipment elements (high pressure feed heaters (HPFH), low pressure feed heater (LPFH)), - water chemistry at different points of condensate feed pipe, composition and density of deposits on HET surface, efficiency ...
We present the results obtained from tests and studies carried out on the model of tube bundles for a PGV-1000 horizontal steam generator that were conducted for experimentally substantiating the design service life of a steam generator tube bundle intended for use at new nuclear power stations equipped with a PGV-1000MKP steam generator. Measures taken to minimize the incipience and development of local corrosion damage to the heat-transfer tubes and ensure their design service life are substantiated and confirmed.
High power and particle deposition on target materials are encountered in many applications including magnetic and inertial fusion devices, nuclear and high energy physics applications, and laser and discharge produced plasma devices. Surface and structural damage to plasma-facing components due to the frequent loss of plasma confinement remains a serious problem for the Tokamak reactor concept. The deposited plasma energy causes significant surface erosion, possible structural failure, and frequent plasma contamination.
The study required by the West German Ministry of Research and Technology (RS 605) for the Committee on 'Future Nuclear Energy Policy' of the 9th German Parliament is concerned with the following main points: 1) Assessment of technical risks from the social aspect; 2) Discussion of terms and quantification of risks; 3) 'Engineering judgment' and 'questionable' methods in the Fast Breeder analysis of the Society for Reactor Safety (GRS); 4) Assessment criteria of potential damage.
Leachability of neutron irradiated fly ash is investigated as a method for studying element leaching properties of this material with various leaching media. Quantitative aspects of radiation damage are shown to be minor. Therefore, the technique should be applicable for this purpose. It is further shown that this technique affords significant advantages over the conventional post-leaching analysis with respect to utilization of natural solutions for the investigation of fly ash leachability. However, for a few elements such as Pb, Bi, V, and Al, the various nuclear parameters involved invalidate applicability of the present technique.
Leachability of neutron irradiated fly ash is investigated as a method for studying element leaching properties of this material with various leaching media. Quantitative aspects of radiation damage are shown to be minor. Therefore, the technique should be applicable for this purpose. It is further shown that this technique affords significant advantages over the conventional post-leaching analysis with respect to utilization of natural solutions for the investigation of fly ash leachability. However, for a few elements such as Pb, Bi, V, and Al, the various nuclear parameters involved invalidate applicability of the present technique.
The nitric acid solution dissolving nuclear fuel material is transferred with the three way valve called VCV (VCV: vide-casse-vide in Fr.) using vacuum in the Tokai Reprocessing Plant. The initial VCV was not reliable because it had broken with in 1 or 2 years. The cause of failure was damage of the plastic diaphragms in the moving parts. Then, the new VCV valve with stainless-steel bellows was developed. There is no failure in moving parts in 20 years, therefore reliability is significantly improved. (author)
Results of investigation of stress corrosion cracking of steam turbine materials in nuclear, fossil and geothermal power plants have been analysed. The role of factors that cause damage to rotor discs, mono block and welding rotors of steam turbines has been shown. These are yield stress and steel composition, stress intensity coefficient and crack growth rate, composition and temperature of the condensed steam and water, electrochemical conditions. The conclusion has been made about the state of stress corrosion cracking of the rotors materials, and main investigation trends which are necessary to solve this problem have been listed.
The Structural Aging (SAG) Program is carried out by the Oak Ridge National Laboratory (ORNL) under sponsorship of the United States Nuclear Regulatory Commission (USNRC). The Program has evolved from preliminary studies conducted to evaluate the long-term environmental challenges to light-water reactor safety-related concrete civil structures. An important conclusion of these studies was that a damage methodology, which can provide a quantitative measure of a concrete structure's durability with respect to potential future requirements, needs to be developed. Under the SAG Program, this issue is being addressed through: establishment of a structural materials information center, evaluation of structural component assessment and repair technologies, and development of a quantitative methodology for structural aging determinations. Progress to date of each of these activities is presented as well as future plans. 7 refs., 5 figs.
Heavy ions used for biomedical studies fragment when they pass through matter. It is known that different fragments cause different types of biological damage. In this paper, results pertaining to differrent kinds of secondary fragments produced by a /sup 28/Si beam at 463 MeV/nucleon in its interaction with nuclear emulsion are presented. It is observed that the production frequencies of secondary fragments are independent of the target. Partial production cross sections and fluences of the secondary fragments are also discussed. The partial production cross sections for different fragments at three lower energy ranges are practically the same within their statistical errors except for the cross section for Li fragments, which is larger by almost a factor of 1.5 at the lowest energy investigated. The dose contributions of the primary Si beam and its components at different points of the Bragg curve are presented for two different energy ...
The main objectives of research in the field of health effects at the Belgian Nuclear Research Centre SCK-CEN are: (1) to study cancer mortality and morbidity in nuclear workers in Belgium; (2) to document the feasibility of retrospective cohort studies in Belgium; (3) to participate in the IARC study; (4) to elucidate the mechanisms of the effects of ionizing radiation on the mammalian embryo during the early phases of its development; (5) to assess the genetic risks of material exposure to ionizing radiation; (6) to elucidate the cellular mechanisms leading to brain damage after prenatal irradiation; (7) to advise authorities and to provide the general population with adequate information concerning the health risk arising from radiation exposure. Progress and major achievements in these topical areas for 1997 are reported.
This report is the user's manual of seismic system reliability analysis code SECOM2 (Seismic Core Melt Frequency Evaluation Code Ver.2) developed at the Japan Atomic Energy Research Institute for systems reliability analysis, which is one of the tasks of seismic probabilistic safety assessment (PSA) of nuclear power plants (NPPs). The SECOM2 code has many functions such as: Calculation of component failure probabilities based on the response factor method, Extraction of minimal cut sets (MCSs), Calculation of conditional system failure probabilities for given seismic motion levels at the site of an NPP, Calculation of accident sequence frequencies and the core damage frequency (CDF) with use of the seismic hazard curve, Importance analysis using various indicators, Uncertainty analysis, Calculation of the CDF taking into account the effect of the correlations of responses and capacities of components, and Efficient sensitivity analysis by ...
One of the most loaded parts of a steam generator of VVER 440 MW type are the bolts and thread holes of the primary collector cover sealing set. The strength calculations and tensometric measurings performed during operation proved the high degree of a load on the bolts. The conditions of the stress limitation are not met in some cases according to the pertinent standards. The untightnesses at nickel rings occurred during putting the units of Jaslovske Bohunice and Dukovany nuclear power stations into operation. With regard to improve the reliability, the producer has taken measures to improve the quality of the rings and users have introduced more strict regulations for bolts tightening. Due to these measures the high reliability of the set has been obtained from point of view of the tightness, but substantial reduction of bolts and holes threads loading have not been obtained. Several years operation experience proved relatively low service of bolts, ...
Titanium base 'alpha'-alloys (Pt-7M, RK-20 and Ti-5Al-2Zr-1.5V) are considered for their behaviour under neutron irradiation. The role of alloying elements in radiation hardening is discussed depending of neutron fluence and irradiation temperature. For PK-20 alloy three stages of change in mechanical properties are revealed which are following: incubation period and weak hardening, intense radiation hardening, radiation hardening attenuation. Irradiation temperature rise results in an increase of incubation period and threshold neutron fluence. A special attention is paid to hydrogen absorption in #alpha#-titanium alloys under irradiation. It is concluded that titanium base 'alpha'-alloys are serviceable as structural materials in nuclear plants with allowance made for peculiar features of their radiation behaviour. 4 refs.; 7 figs.; 1 tab.
Corrosion of steam generator heat transfer tubes (SGHTT) is one of the important problems which affect safety operation of nuclear power plants (NPP), and the hazard of pitting corrosion of heat transfer tubes is the most serious. With an acoustic emission device, the signals during a corrosion test on SGHTT were collected and analyzed, and the corrosion points in the tubes were located accurately. The results show that pitting corrosion of heat transfer tubes has passed through three periods in its development: expansion phase, stationary phase and rapid developing phase. The corrosion damage of HTT can be found earlier with acoustic emission than any other non-destructive testing methods. Acoustic emission can be used for on-line and real-time monitoring of the safety and operation of the steam generator and has therefore a great significance. (orig.)
To understand dynamic developmental processes, living tissues must be imaged frequently and for extended periods of time. Root development is extensively studied at cellular resolution to understand basic mechanisms underlying pattern formation and maintenance in plants. Unfortunately, ensuring continuous specimen access, while preserving physiological conditions and preventing photo-damage, poses major barriers to measurements of cellular dynamics in indeterminately growing organs such as plant roots. We present a system that integrates optical sectioning through light sheet fluorescence microscopy with hydroponic culture that enables us to image at cellular resolution a vertically growing Arabidopsis root every few minutes and for several consecutive days. We describe novel automated routines to track the root tip as it grows, track cellular nuclei and identify cell divisions. We demonstrate the system's capabilities by collecting data on divisions and ...
Protective goals set the line of orientation of tasks and activities in the field of accident prevention. They have to be based on safety-science methods in order to develop from the conceptual idea to the practically feasible solution, while using the scientific methods to take into account the facts and the capabilities of a situation and, proceeding from them, finding an efficient and rational, optimal pragmatic approach by way of various strategies or tactics. In this process, the activities of defining, informing, thinking and developing need the proper terminology. Safety is absence of danger, protection is limitation of danger and prevention of damage. So it is protection what is needed with danger being given, and risks have to be minimized. Riskology is a novel method of safety science, combining risk analysis and risk control into a systematic concept which is practice-oriented. Applying this to the field of nuclear engineering, the ...
Modifications of the structure and mechanical properties in LiF crystals irradiated with MeV-energy Au ions have been studied using nanoindentation, atomic force microscopy and optical spectroscopy. The nanostructuring of crystals under a high-fluence irradiation (above 1013 ions/cm2)?was?observed. Nanoindentation tests show a strong ion-induced increase of hardness (up?to 150?200%), which is related to the high volume concentration of complex color centers, defect aggregates, dislocation loops and grain boundaries acting as strong barriers for dislocations. From the?depth profiling of the hardness and energy loss it follows that both nuclear and electronic stopping mechanisms of MeV Au ions contribute to the creation of damage and hardening. Whereas the electronic stopping is dominating i...
A Y-Mg-Si-Al-O-N glass was submitted to swift heavy-ion bombardment at GANIL (Caen, France) and the influence of irradiation on the mechanical properties was studied. The mechanical properties of the glass were characterized both before and after irradiation. Changes in hardness, elastic modulus and fracture toughness of the near-surface irradiated layer were determined using indentation techniques. SRIM calculations allowed to estimate the ions penetration range and the energy deposition relative to electronic and nuclear interactions, which can be correlated to the experimental damaged depth. Meyer's hardness and Young's modulus decrease by about 30 %, while fracture toughness is increased by more than 40 %. (authors)
Problems are discussed of heat exchange tubes of Westinghouse type vertical steam generators exhibiting corrosion damage such as point corrosion, planar corrosion, tube denting, corrosion stress cracking, crevice corrosion, fretting corrosion and intergranular corrosion. Attention is also paid to problems of WWER-440 type horizontal steam generators, where the level fluctuation area is critical; noncompact porous deposits of the corrosion products give rise to crevice effects and cause significant concentration of chloride ions and other additions. This problem can be partly resolved by a modification of the collector design at the level variation area. An additional measure is the production of steel 08Kh18N10T with a very low level of harmful elements and inclusions. (Z.M.). 3 figs., 11 refs.
Considering beryllium as plasma facing armour this paper presents recent results obtained in Russia. A special process of joining beryllium to a Cu-alloy material structure is described and recent results of thermal cycling tests of such joints are presented. Summarizing the results, the authors show that a Cu-alloy heat sink structure armoured with beryllium can survive high heat fluxes ({>=}10 MW/m{sup 2}) during 1000 heating/cooling cycles without serious damage to the armour material and its joint. The principal feasibility of thermal cycling of beryllium grades and their joints directly in the core of a nuclear reactor is demonstrated and the main results of this test are presented. The paper also describes the thermal cycling of different beryllium grades having cracks initiated by previously applied high heat loads simulating plasma disruptions. (orig.)
After a brief review of the degradations occurring on tubes of Inconel 600 in steam generators of PWR power stations emphasis is put on the conditioning of the secondary water and more particularly on the condensate treatment in the units of Doel which work on heavily polluted brackish water. The important role of non-destructive testing and eddy-current testing is also pointed out, method developed by Laborelec. The operational experience shows that Belgian stations are nearly not concerned by the degradations mostly found in power stations in other countries which shows the efficiency of the conditioning of the secondary water. On the other hand, other problems have occurred, resulting from: damage caused by foreign objects; fouling of tube before commissioning, cracking of bends and at the limit of the dudgeoning and leaking plugs. (AF).
In order to maintain a safe operation and availability of generating facilities, qualitative and quantitative assessment of piping vibration was performed vibration sources and damages of piping support was identified on the second piping system of Wolsung nuclear power plant unit 1 .Inspected piping supports and structures in both hot and cold condition .Established evaluation procedures of piping vibration .Performed the static analysis of 2 nd piping system .Established optimal vibration reducing method .The measured vibration level after installing rigid supports and energy absorbing type restraint was reduced about 7 times in velocity unit (author). 24 refs., 95 figs.
Since the first operation of nuclear steam generator early 1960s, its performance requirements have been met but the steam generator problems have been met but the steam generator problems have been major cause of reducing the operational reliability, plant safety and availability. U-tube assembly of steam generator forms the primary system pressure boundary of the plant and have experienced several types of tube degradation problems. Tube failure and leakage resulting from the degradation will cause radioactive contamination of secondary system by the primary coolant, and this may lead to unplanned plant outages and costly repair operations such as tube plugging or steam generator replacement. For the case of steam generators for heavy water reactors, e.g. Wolsong 2, 3, and 4 NPP, a high cost of heavy water will be imposed additionally. During the plant operation, steam generator tubes can potentially be subject to adverse environmental conditions which will cause ...
Iron is one of the main constituents of stainless steel which is used as a structural material in nuclear reactors. In fast and conceptual fusion and fusion-fission hybrid systems the primary energy range of neutron interaction lies between 1 and 20 MeV which opens up several reaction channels. The reaction cross-sections in this energy range are important for dosimetry, radiation damage, neutronics and safety studies of nuclear reactors. Keeping this in view Nuclear Data Section of the International Atomic Energy Agency has sponsored a Research Co-ordination Programme on Methods for the Calculation of Fast Neutron Nuclear Data for Structural Elements. Under this programme we propose to study (n,n'), (n,2n), (n,3n), (n,p), (n,np), (n,pn), (n,#alpha#), (n,n#alpha#), (n,#alpha#n) and (n,#gamma#) reaction cross-sections. Besides these, total, elastic and discrete level inelastic ...
A closed economic system was assumed for the Veneto Region (Italy) in order to define an appropriate input-output model and assess the future economic and environmental impacts of proposed actions for energy source development and economic growth. Present and forecasted energy demands (to the year 2000) were determined by energy source, e.g., natural gas, coal, petroleum and hydropower for the different consuming sectors - agriculture, transportation, industry, etc. Forecasts were made of the air pollution expected as a result of different types of energy and technology inputs for each sector. These considered planned retrofits towards clean combustion systems. Costs were estimated for the implementation of proposed pollution abatement measures, as well as, for the effects of energy use related environmental damage and measures to restore the environment. Some of the factors taken into account were: the regional impacts of the Italian National Energy Plan; the ...
The Boiler and Pressure Vessel Code (BPVC) of the American Society of Mechanical Engineers (ASME) has introduced a risk based approach into Section XI that covers Rules for Inservice Inspection of Nuclear Power Plant Components. The risk based approach requires application of the probabilistic risk assessments (PRA). Because no industry consensus standard existed for PRAs, ASME has developed a standard to evaluate the quality level of an available PRA needed to support a given risk based application. The paper describes the PRA standard, Section XI application of PRAs, and plans for broader applications of PRAs to other ASME nuclear codes and standards. The paper addresses several specific topics of interest to Section XI. Important consideration are special methods (surrogate components) used to overcome the lack of PRA treatments of passive components in PRAs. The approach allows calculations of conditional core ...
The Boiler and Pressure Vessel Code (BPVC) of the American Society of Mechanical Engineers (ASME) has introduced a risk based approach into Section XI that covers Rules for Inservice Inspection of Nuclear Power Plant Components. The risk based approach requires application of the probabilistic risk assessments (PRA). Because no industry consensus standard existed for PRAs, ASME has developed a standard to evaluate the quality level of an available PRA needed to support a given risk based application. The paper describes the PRA standard, Section XI application of PRAs, and plans for broader applications of PRAs to other ASME nuclear codes and standards. The paper addresses several specific topics of interest to Section XI. Important consideration are special methods (surrogate components) used to overcome the lack of PRA treatments of passive components in PRAs. The approach allows calculations of conditional core damage ...
The Boiler and Pressure Vessel Code (BPVC) of the American Society of Mechanical Engineers (ASME) has introduced a risk based approach into Section XI that covers Rules for Inservice Inspection of Nuclear Power Plant Components. The risk based approach requires application of the probabilistic risk assessments (PRA). Because no industry consensus standard existed for PRAs, ASME has developed a standard to evaluate the quality level of an available PRA needed to support a given risk based application. The paper describes the PRA standard, Section XI application of PRAs, and plans for broader applications of PRAs to other ASME nuclear codes and standards. The paper addresses several specific topics of interest to Section XI. Important consideration are special methods (surrogate components) used to overcome the lack of PRA treatments of passive components in PRAs. The approach allows calculations of conditional core damage ...
Stress corrosion cracks have been discovered in Group Distribution Headers (GDH) at the Ignalina and Chernobyl Nuclear Power Plants. This increases the probability that a guillotine pipe break can occur that creates a whipping pipe (GDH) with the potential to damage surrounding structures-i.e. adjacent GDH and its attached piping or adjacent reinforced concrete compartment wall. The GDH is the most important component for reactor safety in case of an accident. Emergency Core Cooling System (ECCS) piping is connected to the GDH piping such that, during an accident, coolant passes from the ECSS into the GDH. Presented in this paper is the transient analysis of a Group Distribution Header following a guillotine break at the blind end of the header. Using a very conservative force loading function, the transient response of a whipping RBMK-1500 GDH along with neighboring concrete walls and pipelines is obtained using finite element methodology. The ...
The effects of various antioxidants and antioxidant concentrations on the radiation and thermal stability of EPDM and XLPE polymers used for insulation of electric cable in nuclear power plants were measured. The objective was to determine if particular antioxidants could be identified as being especially effective for stabilization against radiation aging and combined thermal and radiation aging. Elongation to rupture was used as the measure of stability. Materials were irradiated to doses up to 2 MGy (200 Mrad) at a dose rate of 200 to 300 Gy/h in the Cobalt-60 Gamma Irradiation Facility at the University of Virginia. All of the antioxidants tested, which were known to provide excellent thermal stability, also provided good stability for radiation aging and combined thermal/radiation aging, although small differences between antioxidants were noted. No antioxidant or antioxidant combination was identified as being especially outstanding. Stabilization against ...
Magnetic particles (MAG*SEP"S"M) coated with various absorbents were evaluated for the separation and recovery of low concentrations of cesium from nuclear waste solutions. The MAG*SEP"S"M particles were coated with (1) clinoptilolite, (2) transylvanian volcanic tuff, (3) resorcinol formaldehyde, and (4) crystalline silico-titanate, and then were contacted with a Hanford supernatant simulant. Particles coated with the crystalline silico-titanate were identified by Bradtec as having the highest capacity for cesium removal under the conditions tested (variation of pH, ionic strength, cesium concentration, and absorbent/solution ratio). The MAG*SEP"S"M particles coated with resorcinol formaldehyde had high distribution ratios values and could also be used to remove cesium from Hanford supernant simulant. Gamma irradiation studies were performed on the MAG*SEP"S"M particles with a gamma dose equivalent to 100 cycles of use. This irradiation decreased the loading ...
On February 1, 1984, the US Nuclear Regulatory Commission issued Generic Letter 84-04 on the subject of postulated pipe breaks in pressurized water reactor (PWR) primary coolant loops, opening the way for pipe-whip restraint exemptions. The letter substitutes the leak-before-break (LBB) criteria for the double-ended guillotine break regarding PWR primary reactor coolant system (RCS) piping and asymmetric blowdown loads. The LBB criterion refers to the fact that a piping flaw will leak before it breaks. The current requirement to provide pipe-whip restraints is applied within the plant to all high-energy piping with a potential for damaging structures, systems, and components essential to safe reactor shutdown. This includes primary RCS piping 30 in. and larger as well as smaller piping systems. A study was performed to evaluate the applicability of the LBB criteria proposed in NUREG-1061 to the latter set. The costs and benefits of this kind of ...
Threshold pump intensity values leading to irreversible damage to colored laser elements based on elastic polymers were measured. The damage to colored elastomers is connected with absorbing microinclusions but is independent of molecular absorption. It is shown that damage to the elastomers has a pronounced threshold character in contrast to the microdamage accumulation effect in glassy polymers. The damage threshold for elastomers is 1.5 times higher, which is connected with the absence of microstresses (characteristics for organic glasses) in the specimens. 13 references.
The paper addresses the major items of relevance to compensation for nucleardamage under civil liability law. The revision of the Vienna Convention deserves support as a contribution to enhancing the protection of those who suffered damage, and of the environment. The results of the revision will have an impact on the liability regimes in existing and future signatory states, and to some extent will also set the goals of a future reshaping of the Paris Convention, all the more since the Joint Protocol calls for harmonization of at least basic provisions of substantive law in the two Conventions. (orig./HP) [Deutsch] Es werden die wesentlichen Punkte dargestellt, die fuer die zivilrechtliche Praxis im Schadensfall von Belang sein koennten. Die Revision ist als Beitrag zu einem verbesserten Schutz Geschaedigter, aber auch der Umwelt zu begruessen und zu unterstuetzen. Die Ergebnisse werden sich auf die Rechtsordnungen der ...
Candida albicans frequently causes superficial infections by invading and damaging epithelial cells, but may also cause systemic infections by...Full Text Available
DNA damage is a threat to genomic integrity in all living organisms. Plants and green algae are particularly susceptible to DNA damage especially that caused by UV light, due to their light dependency...Full Text Available
The issue of beam-induced damage on diffractive hard X-ray optics is addressed. For this purpose a systematic study on the radiation damage induced by a high-power X-ray beam is carried out in both...Full Text Available
The steam generator (SG) is one of the most critical components of the heat transfer system in nuclear generation stations. Testing the structural integrity of SG tubing and SG internals is a key element of the fitness-for-service assessments to assure the safe and continuous operation of nuclear power plants. Recent eddy current (ET) inspections of two nuclear power plants revealed degradation of some of the tube support plate (TSP) structures, which was also confirmed by visual inspection. The phenomena was described as metal loss, caused by flow-accelerated corrosion of the carbon steel trefoil support plate and varying from minor to complete loss of the ligaments. This loss of TSP ligaments results in lack of support for the adjacent tubes making them more susceptible to fretting-wear damage and fatigue cracking. A signal analysis method, based on the responses at low frequency of two types of eddy ...
Large-scale decommissioning of Russian nuclear-powered submarines (NPS) and their utilization prospects gave rise to numerous complicated scientific and technical, as well as economic, problems. Problems of handling of radioactive equipment from the reactor compartments (RC) are among the vital ones, arousing a growing concern with the public. Without solution of the problems the processes of NPS utilization can not be considered completed. It involves potential hazard, for the environment both from NPS being paid up (temporal on-float storage) with unloaded spent nuclear fuel (SNF), and RC, cut from submarine hull, containing highly radioactive equipment and materials but no SNF. Diverse variations of the concept of reactor compartment handling of NPS subject to, utilization are possible, but, in principle, there are essentially two variants: (1) RC utilization directly in the course of NPS utilization, envisaging removal of radioactive ...
... The revised work plan emphasized the research priorities of preharvest rodent damage to rice, the importance of postharvest food losses to rodents ...
Wade. Jackson. - Army. VTD at NASA. Langley. ABSTRACT. Panel size has a large effect on the impact response and resultant damage level of honeycomb sandwich ...
Full text of publication follows: The Nuclear Power Plants (NPPs) are always designed for the highest level of safety against postulated accidents which may be initiated due to internal or external causes. One of the external/internal causes, which may lead to accident in the reactor and its associated systems, is fire in certain vital areas of the plant. Conventionally, the fire containment approach and/or the fire confinement approach is used in designing the fire protection systems of NPPs. Indian NPPs (PHWRs) follow the combined approach to ensure plant safety and all newly designed plants are required to comply with the provisions of Atomic Energy Regulatory Board (AERB) fire safety Guide. In respect of older plants, the reassessment of adequacy of fire safety provisions in the light of current advances has becomes essential so as to decide upon the steps for retrofitting. Keeping this in mind the deterministic fire hazard analysis was carried out for the ...
The existence of problems with wild pigs (Sus scrofa) is nothing new to the Western Hemisphere. Damage by these introduced animals was reported as far back as 1505 by the early Spanish colonies in the Caribbean, where wild pigs were killing the colonists cattle. Droves of these animals also ravaged cultivated crops of maize and sugarcane on islands in the West Indies during this same time period. These wild pigs reportedly were very aggressive and often attacked Spanish soldiers hunting rebellious Indians or escaped slaves on these islands, especially when these animals were cornered. The documentation of such impacts by introduced populations of this species in the United States has subsequently increased in recent years, and continued up through the present (Towne and Wentworth. 1950, Wood and Barrett 1979, Mayer and Brisbin 1991, Dickson et al. 2001). In spite of a fairly constant history in this country since the early 1900s, wild pigs have had a dramatic ...
Heterochromatin constitutes a significant portion of the genome in higher eukaryotes; approximately 30% in Drosophila and human. Heterochromatin contains a high repeat DNA content and a low density of protein-encoding genes. In contrast, euchromatin is composed mostly of unique sequences and contains the majority of single-copy genes. Genetic and cytological studies demonstrated that heterochromatin exhibits regulatory roles in chromosome organization, centromere function and telomere protection. As an epigenetically regulated structure, heterochromatin formation is not defined by any DNA sequence consensus. Heterochromatin is characterized by its association with nucleosomes containing methylated-lysine 9 of histone H3 (H3K9me), heterochromatin protein 1 (HP1) that binds H3K9me, and Su(var)3-9, which methylates H3K9 and binds HP1. Heterochromatin formation and functions are influenced by HP1, Su(var)3-9, and the RNA interference (RNAi) pathway. My thesis project investigates how ...
A probabilistic precursor study provides a complement to the 'root cause' analysis approach by focusing on how an event might have developed adversely, and implies the mapping of an operational event on a probabilistic risk model of the plant in order to obtain a quantitative assessment of the safety significance of the event. In order to benefit from state-of-the-art PSA features but also to assure repeatability of the analysis, a comprehensive set of PSAEA guidelines was developed. This PSAEA procedure was established in 1996-1998 by Enconet Consulting in the framework of an international project on behalf of - and involving - the nuclear regulatory bodies from 6 countries: AECB (Canada), AVN (Belgium), CSN (Spain), HSK (Switzerland), NII (United Kingdom) and SKI (Sweden). The PSAEA procedure defines preliminary requirements for the PSA model and code, and identifies input requirements such as information on plant status, event sequence chronology and causes. The ...
On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB, the U.S. agency responsible for determining the cause of transportation accidents), to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), ...
In Aug 2002, the National Nuclear Safety Administration of China issued the policy statement for building new nuclear power plants, which requires the probability based safety goal of severe core damage must be lower than 10"-"5/a. The station blackout accident would be possible to cause a severe accident if there were no effective engineering measures to prevent or mitigate the consequences of the accident. By using MELCOR1.8.5 and KORIGEN codes, the present paper has simulated the station blackout accident for Daya Bay Nuclear Power Plant and calculated the source term and radioactivity of main fission products in the containment in the late phase of the accident. CsI is found the main part of aerosol in the containment. The Xe133 and Xe133m start releasing from the containment after its failure, and the upper limit of the amount of released radioactivity is evaluated less than 5.5 x 10"1"5Bq. The ...
This report describes the basis, results, and related risk implications of an analysis performed by an ad hoc working group of the U.S. Nuclear Regulatory Commission (NRC) to assess the containment bypass potential attributable to steam generator tube rupture (SGTR) induced by severe accident conditions. The SGTR Severe Accident Working Group, comprised of staff members from the NRC`s Offices of Nuclear Reactor Regulation (NRR) and Nuclear Regulatory Research (RES), undertook the analysis beginning in December 1995 to support a proposed steam generator integrity rule. The work drew upon previous risk and thermal-hydraulic analyses of core damage sequences, with a focus on the Surry plant as a representative example. This analysis yielded new results, however, derived by predicting thermal-hydraulic conditions of selected severe accident scenarios using the SCDAP/RELAP5 computer code, flawed tube failure ...
Probabilistic assessment methods can be used to identify specific plant vulnerabilities. Application of such methods can also facilitate selection among system design alternatives available for safety enhancements. The quality of assessment results is however strongly dependent on realistic and accurate input data for modelling of system component behaviour and failure modes during conditions to be assessed. Use of conservative input data may not lead to results providing guidance on safety upgrades. Adequate input data for probabilistic assessments seems to be lacking for at least failure modes of some electrical components when exposed to a fire. This report presents an attempt to improve the situation with respect to such input data. In order to take advantage of information in existing documentation of fire incident occurrences some of the lessons learned from the fire at Browns Ferry Nuclear Power Plant on March 22, 1975 are discussed in this report. Also a ...
Fuel rod failures produce a release of fission products into primary coolant system. Since nuclear power plants have licensing limits for the release of volatile fission products to the environment (off-gas limits) detailed monitoring of the development of clad failure is necessary. In case of fuel rod failure a release of fission products into the primary coolant system arises. Fission gases accumulated in the free volume of a fuel rod escape through the clad defect. Water entering the fuel rod reacts with fission products, forming volatile chemical compounds. These may escape in a similar manner into the fission gases. Other compounds may dissolve and may be carried outside the fuel rod as dissolved species. Consequently, the distribution of these fission products, in the cross section of the fuel rod, is modified. An implementation of the maximum entropy gamma computed tomography technique is used to obtain such distributions in the area of the fuel rod ...
The author furnishes a review of incidents of major damage to high-output steam turbines. At the same time, he thereby underlines the call for an improvement in the exchange of experience on such damage and its causes at international level. Only the careful observance of past damage experience - including that of foreign manufacturers and operators - complete and modern monitoring equipment and the painstaking evaluation of all data furnished by such equipment can keep the risk of new technical development within economically tolerable limits. (orig.).
The hardening and embrittlement of reactor pressure vessel (RPV) steels is of great concern in the actual nuclear power plant life assessment. This embrittlement is caused by irradiation-induced damage, like vacancies, interstitials, solutes and their clusters. The current procedure to estimate material properties for the irradiated pressure vessels is based on Charpy-V tests of identical material located at the inner shell of the reactor. But the reason for the embrittlement of the materials is not yet totally known. The real nature of the irradiation damage should thus be examined as well as its evolution in time. Fe-Cu binary alloys are often used to mimic the behaviour of such steels. Their study allows. Identifying some of the defects responsible of the hardening, especially when compared to pure iron or C-micro-alloyed iron. More recently the influence of manganese and nickel in low-Cu RPV steels has become a ...
A series of radioactive catastrophes (from 1948 to 1967) in the Southern Urals in the USSR led to intensive environmental contamination. Radioactive wastes were dispersed over the 20000 km(2) territory of four provinces-Chelyabinsk, Sverdlovsk, Tyumen' and Kurgan-due to the activity of the military facility that was built in 1948 for the production of nuclear bomb plutonium. The results of 50 years of investigations into the consequences of these disasters allow a general picture of the events that occurred to be reconstructed and allow the medical consequences of the irradiation of about half a million residents to be depicted. However, due to the atmosphere of secrecy and inadequate medical procedures, the results of medical studies of radiation victims are scant. The current protocols present a unique opportunity to study the DNA damage at the nucleotide resolution level in the genome of inhabitants of the given region, who presumably ...
On March 28, 1979, the Pennsylvania Three Mile Island nuclear power plant Unit 2 (TMI-2) suffered a partial fuel-melt accident. During this accident, over 20,000 lb of molten fuel flowed through holes melted through the baffle plates and through the lower-core support assembly (LCSA). The molten fuel subsequently resolidified in the bottom of the reactor vessel. The lower-core support assembly of the TMI-2 reactor was not structurally damaged during the accident. In order to permit defueling of that region of the core, the LCSA was cut to permit access. A five-axis teleoperator was developed to deliver plasma arc cutting, rotary grinding and abrasive waterjet cutting of end effectors to the LCSA. Complex geometry sectioning was completed in a mock-up facility at chemistry and pressure conditions simulating those of the vessel, prior to actual in-vessel operations. In-vessel activities began in early May 1988 and were completed on April 11, ...
The study was performed for evaluating the risk effect of digital systems on the total plant. Based on risk monitor, a fault tree model for the Korean Standard Nuclear Power Plants (KSNPP), we integrate the fault-tree models for Digital Plant Protection System (DPPS) and Digital Engineered SaFety Actuation System (DESFAS) which are the most important safety-critical I and C systems in the KSNPP. In this study, however, three important factors (the probabilities of manual actuation failure, the software failure probability, and the watchdog timer fault coverage) are treated as the variables of the sensitivity study because quantification methodologies for these factors are not developed yet. Not only the unavailability of digital safety-critical system itself, but also the risk effect of digital systems on the total plant should be assessed to prove the safety of digital systems. The result of sensitivity study shows that the Anticipated-Transient-Without-Scram ...
Canisters with spent nuclear fuel can obviously not be located within deformation zones as this might jeopardise their long term mechanical stability and thereby constitute a potential hazard to the biosphere. Less apparent, but equally important, is the fact that earthquakes trigger reactivation, slip, of structures some distance from their hypocentres due to, among many other factors, stress redistribution. Fault slip across a deposition hole might damage the isolation capacity of the canister and thereby jeopardise the overall integrity of the barrier system. Therefore, the following question might be posed: What is the distance from a deformation zone beyond which a canister can be safely emplaced? This respect distance cannot be readily computed because, unknown future events aside, there are some complicated aspects that need to be addressed e.g. degree of conservatism, scale, our ability to model ice sheets and earthquakes, etc. In this ...
When a nuclear power station was installed on the Meuse in central Belgium, the impact of thermal, radioactive, and chemical waste on the water of the Neuse and on its biocenoses was studied. Three successive periods of development of the channel bed and the flood plain in Belgium have occurred, and their hydrological, physicochemical, and ecological consequences have been examined. Since the last century, the ecosystem of the Meuse has undergone, due to the increasing activity of man, modifications of increasing importance: marked reduction of the water flow, a drastic increase in the suspended material being transported, a degree of eutrophication of the water, and the disturbance of the original floral and faunal communities. The causes of this evolution of the Meuse can be itemized as different types of human interference in descending order of importance: (1) occupation of the catchment area; (2) encroachment on the flood plain; (3) encroachment on the channel ...
Radioadapted chicken embryo cells (X-irradiation in ovo with 10 cGy at the 14th day of development with priming periods of 24 h) were treated in vitro by challenge doses of 14 different DNA- and/or chromatin-interactive agents, including X-rays. A decrease in the cellular damage, as measured by scheduled DNA synthesis, was only observed with X-irradiation. Sedimentation of nucleoids as well as viscosity of alkaline lysates from ethidium bromide (0.35-400 {mu}g/ml)-, vovobiocin (125-1800 {mu}g/ml)-, and hyperthermia (30 min at 43 and 45 )-treated cells suggest a higher tendency of radioadapted cells to undergo positive DNA supercoiling. When DNA from adapted and non-adapted chicken embryo cells was used as substrate, neither its digestion by DNase I nor the inhibition of DNase I activity by various DNA-interactive agents was changed in primed cells. From the previous investigations as well as from the present results it is concluded that an increase of tightening of ...
The reliability of the surface condenser is a key factor in plant performance level and maintenance cost optimization. This is especially the case for thermal nuclear plants where condenser raw wa-ter ingress can introduce contamination into the chemically-controlled, steam/water loop potentially causing damage to sensitive equipment. Two important parameters must be taken into account when attempting to optimize the quality and the reliability of condenser tubing. They include selecting the appropriate material according to the cooling water corrosion level present. A second and equally important parameter is the manufac-turing of the tubing product itself. This paper will identify methods to optimize manufacturing processes and improve tubing quality, according to VALTIMET's 30 years of condenser welded tubing production experience. Those methods complete the core manufacturing process (forming and welding), through improvement of ...
The purpose of this document is to provide a framework for developing protective strategies in the longer term following an accidental release of radionuclides to the offsite environment. This advice covers all forms and scales of accidental release, including releases from nuclear sites and reactors, weapons accidents, and damaged industrial or medical sealed sources. The countermeasures considered are those intended to protect the public from external irradiation from radionuclides deposited in the environment, from the inhalation of resuspended radionuclides, and from inadvertent ingestion of radionuclides resulting from contact with contaminated surfaces. The Board terms these recovery countermeasures. They can be broadly grouped as either decontamination measures (ie measures that deal directly with the radionuclides, whether by removing them, shielding them or physically or chemically bonding them) or as restricted access measures (ie ...
Presented in this paper is the transient analysis of a Group Distribution Header (GDH) following a guillotine break at the end of the header. The GDH is the most important component of reactor safety in case of accidents. Emergency Core Cooling System (ECCS) piping is connected to the GDH piping such that, during an accident, coolant passes from the GDH into the ECCS. The GDH that is propelled into motion after a guillotine break can impact neighboring GDH pipes or the nearest wall of the compartment. Therefore, two cases are investigated: GDH impact on an adjacent GDH and its attached piping; and GDH impact on an adjacent reinforced concrete wall. A whipping RBMK-1500 GDH along with neighboring concrete walls and pipelines is modeled using finite elements. The finite element code NEPTUNE used in this study enables a dynamic pipe whip structural analysis that accommodates large displacements and nonlinear material characteristics. The results of the study indicate that a whipping GDH ...
Special T-shaped feedwater distribution pipes were installed in steam generators at the Loviisa (Finland) and Rovno (Russia) nuclear power plants. The new shape was tested in an extensive testing programme. Since the tubes frequently suffer from corrosion damage, large-scale water hammer experiments were performed on a model facility in 1996. The main objectives of the water hammer experiments were to find out the prevailing parameters leading to water hammers, as well as the sensitivity of hammering to boundary conditions. A water hammer may occur when the mass flow rate into the steam generator exceeds 6 kg/s and the temperature difference between steam generator and feedwater exceeds 100 degC. Visual experiments and stress analyses of the pipe were also carried out. The weakest part, the T-joint, may hold against such water hammers only for a limited time of the order of few minutes. (M.D.).
Radiotherapy with high-energy carbon ion beams can be more advantageous compared to photons because of better physical dose distribution and higher biological efficiency in tumour cell sterilization. Despite enhanced normal tissue sparing, damage incurred by normal cells at the beam entrance is unavoidable and may affect the progeny of surviving cells in the form of inheritable cytogenetic alterations. Furthermore, the quality of the beam along the Bragg curve is modified by nuclear fragmentation of projectile and target nuclei in the body. We present an experimental approach based on the use of a polymethylmethacrylate (PMMA) phantom that allows the simultaneous exposure to a particle beam of several biological samples positioned at various depths along the beam path. The device was used to measure the biological effectiveness of a 60 MeV/amu carbon-ion beam at inducing chromosomal aberrations in G{sub 0}-human peripheral blood lymphocytes. ...
The proposed ERICAM model exhibits deficiencies of a nature making it inacceptable to responsible governments. These deficiencies are: it does not provide the required financial security. The availability of insurance coverage will be dependent on the situation in the financial markets. Pricing will not be determined by the absolute probability of incidents causing damage, so that this may entail a distortion of allocations of resources. (orig./HP) [Deutsch] Das ERICAM Modell hat Konstruktionsmaengel, dass es sicher fuer verantwortliche Regierungen nicht in Frage kaeme, dessen Realisierung in Erwaegung zu ziehen. Die wichtigsten sind: Die benoetigte Sicherheit der Deckungsmittel ist nicht gegeben. Die Lage an den Finanzmaerkten dominiert die Verfuegbarkeit der Deckungsmittel. Die Preisbildung wird nicht durch die absolute Schadenswahrscheinlichkeit bestimmt, so dass eine Verfaelschung der Allokation von Ressourcen eintreten wuerde. (orig./HP)
The integrity of the cables located in the target room is very important in the Fire PSA, because the CDF and CCDP are changed according to the results of a cable integrity that depends on the surrounding gas temperature. The conservative assumptions used in the Fire PSA typically specify that all of the equipment and cables of a room would fail when a fire happens in the room. But the realistic assessment of a fire risk by using a fire simulation tool has become necessary in the Fire PSA as described in the ANS Fire PRA Standard. This paper evaluates the cable integrity of eight pump rooms in the nuclear power plant by using the CFAST zone fire model. The upper layer gas temperature of each room is estimated, and an analysis based on the results of model simulations is used to judge the cable integrity. According to the analysis results, the integrity of the cable located in the upper layer in the pump rooms is maintained without any thermal ...
Many pump reliability problems in the Nuclear Power Plants (NPPs) are being attributed to the operation of the pump at flow rates well below its best efficiency point(BEP). Generally, the manufacturer and the user try to avert such problems by specifying a minimum flow, below which the pump should not be operated. Pump minimum flow usually involves two considerations. The first consideration is normally termed the 'thermal minimum flow', which is that flow required to prevent the fluid inside the pump from reaching saturation conditions. The other consideration is often referred to as 'mechanical minimum flow', which is that flow required to prevent mechanical damage. However, the criteria for specifying such a minimum flow are not clearly understood by all parties concerned. Also various factor and information for computing minimum flow are not easily available as considering for the pump manufacturer' proprietary. The objective of this study ...
We have investigated tailoring damage effects of explosive devices by addition of unconventional materials, specifically combustible metals. Initial small-scale as well as full-scale testing has been performed. The explosives functioned to disperse and ignite these materials. Incendiary, enhanced-blast, and fragment-damage effect have been identified. These types of effects can be used to extend the damage done to hardened facilities. In other cases it is desirable to disable the target with minimal collateral damage. Use of unconventional materials allows the capability to tailor the damage and effects of explosive devices for these and other applications. Current work includes testing of an incendiary warhead for a penetrator.
The marine environment is becoming increasingly contaminated by environmental pollutants with the potential to damage DNA, with marine sediments acting as a sink for many of these contaminants. Understanding genotoxic responses in sediment-dwelling marine organisms, such as polychaetes, is therefore of increasing importance. This study is an exploration of species-specific and cell-specific differences in cell sensitivities to DNA-damaging agents in polychaete worms, aimed at increasing fundamental knowledge of their responses to genotoxic damage. The sensitivities of coelomocytes from three polychaetes species of high ecological relevance, i.e. the lugworm Arenicola marina, the harbour ragworm Nereis diversicolor and the king ragworm Nereis virens to genotoxic damage are compared, and dif...
A statistical evaluation of rotor blade damage in axial steam turbines affords an insight into the extent of the repair costs incurred and reveals the types of defects and shortcomings which cause such damage. The great amount of rotor blade damage discovered during control inspections will surprise even many turbine experts. The statistical evaluation is followed by a review of the more frequent causes of damage and their characteristic features, illustrated on the basis of practical examples. This contribution is intended as an aid to both the manufacturers and operators of steam turbines in preventing the oft almost classic types of faults which constantly recur. (orig.).
An investigation was made of the accumulation of laser damage to transparent polymers irradiated with nanosecond pulses from neodymium and ruby lasers. The damage was investigated by the method of scattering and luminescence in the visible and near ultraviolet parts of the spectrum. It was established that there were two stages in laser damage by repeated irradiation with pulses of intensity below the single-shot damage threshold. An absorbing defect evolved during the first stage in such a way as to create a thermal instability in the surrounding matrix. During the second stage this thermal instability caused spatial growth of laser damage because of propagation of an ionization-inducing absorption wave with a front traveling at the rate governed by the electron component of the thermal conductivity.
In this paper a new procedure, addressed as Interpolation Damage Detecting Method (IDDM), is investigated as a possible mean for early detection and location of light damage in a structure struck by an earthquake. Damage is defined in terms of the accuracy of a spline function in interpolating the operational mode shapes (ODS) of the structure. At a certain location a decrease (statistically meaningful) of accuracy, with respect to a reference configuration, points out a localized variation of the operational shapes thus revealing the existence of damage. In this paper, the proposed method is applied to a numerical model of a multistory frame, simulating a damaged condition through a reduction of the story stiffness. Several damage scenarios have been considered and the results indicate the effectiveness of the method to assess and localize ...
The National Nuclear Data Center provides information on nuclear reactions, nuclear structure, and decay data, and is a part of the Nuclear Data Center Network, established to coordinate the compilation and dissemination of nuclear data on an international scale.
BackgroundWe examined the effects of short-term consumption of whey protein isolate on muscle proteins and force recovery after eccentrically-induced muscle damage in healthy individuals.MethodsSeventeen...Full Text Available
The regular occurrence of large-scale earthquakes in Japan necessitates the use of earthquake disaster prevention systems that focus on gathering damage information on gas supply facilities immediately after an earthquake strikes and minimizing the damage. This paper discussed the development of an earthquake damage estimation system for city gas pipelines that can show damage information in real-time by using earthquake records obtained from densely deployed earthquake observation networks and the most advanced telecommunication and information technologies. The paper summarized the earthquake damage estimation system (EDES) and Toho Gas disaster prevention measures. Specific topics that were discussed included the Toho Gas supply method; earthquake countermeasures; construction of computer systems; normal and emergency operation of EDES; and verification of functions in actual ...
Service, Alaska Regional Office Prince William Sound, photo: Mandy Lindeberg Office of Exxon Valdez Oil Spill (EVOS) Damage Assessment and Restoration About NOAA Fisheries' EVOS...
Because copper catalyzes the conversion of H2O2 to hydroxyl radicals in vitro, it has been proposed that oxidative DNA damage may be an important component of copper toxicity....Full Text Available
One of the most pervasive ideas regarding the causes of aging is that longevity is constrained in large measure by damage to macromolecules. An increasing body of cellular and molecular data, generated...Full Text Available
This book contains over 20 selections. Some of the titles are: Continuum damage mechanics studies on the dynamic fracture of concrete; Dynamic compressive strength of cementitious materials; Rate-sensitivity of mode I and mode II fracture concrete; and An impact damage model of concrete.
A compensatory response, viz. in vivo recovery from radiation damage to mitochondria, occurs in preclimacteric pear fruits (Pyrus communis L.) treated with ionizing...Full Text Available
The annealing behavior of the radiation damage in epitaxial Pd_2Si and NiSi_2 films on Si, due to the implantation of 100 keV Ar ions, is investigated by using the channeling technique with "4He ions. (U.K.).
A novel acidizing process is used to increase the permeability of carbonate rock cores in the laboratory and to remove drilling fluid damage from cores and wafers. Field results show the benefits of the technology as applied both to injector and producer wells.
Disaster impact modeling and analysis uses huge volumes of image data that are produced immediately following a natural or an anthropogenic disaster event. Rapid damage assessment is the key to time critical decision support in disaster management to better utilize available response resources and accelerate recovery and relief efforts. But exploiting huge volumes of high resolution image data for identifying damaged areas with robust consistency in near real time is a challenging task. In this paper, we present an automated image analysis technique to identify areas of structural damage from high resolution optical satellite data using features based on image content.
In order to investigate the influence of grain boundary cavities on the life time of Alloy 800 H various fatigue tests have been performed at 800/sup 0/C. Cavity formation has been observed only in asymmetrical tests. Compared to the corresponding symmetrical tests, the cyclic life time is shorter. As the cavitation damage increases, the ratio of life times in vacuum and in air steadily decreases from an initial value of 5. In extreme cases it can reach a value close to 1. In this case, cavitation damage dominates over the usual damage mechanism, which is cracks from the surface.
It is possible to create nomographs similar to Fig. 2.10 to characterise damage potential of candidate time histories, provided there exists extensive records of earlier time-histories and the damage that they have caused. Thus in order to create such nomographs, one needs the correlated documentation between the input to the structure and the resulting damage. In order to use the Response-Spectra approach, one needs good statistical description of the input to the system. Extensive literature exists on both these methods. The MAC method that has being developed for the present research has yet to be validated. However, if it is successful, it would provide a valuable link between the SEA method and the rational method.
A simple method allowing easy calculation of the spatial damage energy distributions for ion-implanted materials is presented. The direct procedure takes account of the variation with depth of the lateral spreading of implanted ions, as well as the effects of energy transport by the recoiling target atoms. The subsequent computer program LUPIN-3D provides three-dimensional damage distributions and allows the construction of damage energy mappings. Various substrates of technological interest are investigated and several fields of application of the calculation are envisaged. The density of cascades can therefore be determined and heterogeneous amorphization models can be implemented. (orig.).
Full text of publication follows: Understanding the dynamic irradiation effects on silica glasses is important for developing the diagnostic systems used in fusion and fission environments. While fundamental defects having an un-pared electron such as the E' center have been extensively studied, the neutral oxygen deficiency defects have been insufficiently clarified for lack of the detection methods. The ion induced luminescence is one of the probes that can be used to detect non-paramagnetic defects, and to observe creation and annihilation behavior dynamically. In the present study, we examined the characteristics of the ion induced luminescence such as energy, fluence flux and temperature dependence of the luminescence efficiency to analyze damage process quantitatively. Samples of SiO2 glasses were commercially available fused and synthesized silica glasses, produced by Toshiba Ceramics, Co. Ltd.. A thin films of SiO2 deposited on a Si wafer was used to ...
Data on French nuclear electricity generation sites, nuclear power plant operations personnel, operation simulators, nuclear training centers and training statistics are presented.
External radiation dose exceeded 5,000 rad in three cases, and intravaginal radiation dose was 5,000 rad in one case. Radiation damage including perforation was seen in the end of ileus in one case, in the sigmoid and rectum in two cases, and in the end of ileus, sigmoid and rectum in the last case. Satisfactory results were obtained by the removal of the ileocecum in the case of the damage in the end of the ileus. However, only colostomy was performed for the damage in the sigmoid and rectum.
Analysis of damages done by the radiation in a polymer characterized by optic properties of polished surfaces, of uniformity and chemical resistance that the acrylic; resistant until the 150 centigrade grades of temperature, and with an approximate weight of half of the glass. An objective of this work is the development of a method that analyze in automated form the superficial damages induced by radiation in plastic materials means an images analyst. (Author)
Because the bridges over the Rio Grande were to be razed, the investigators were able to introduce simulated cracks in four stages of increasing length into the structure. This paper summarizes the results of ambient and conventional, measured-input, modal analyses, performed on the undamaged structure. Also summarized are the results of conventional modal analyses performed after each stage of damage had been introduced. These tests were intended to quantify the amount of damage necessary to produce changes in the global dynamic properties of the bridge and to form a data base that can be used by other investigators to develop damage identification algorithms. Conventional modal analysis identified changes in the global dynamic properties of the structure only after the final stage of a damage.
EXAFS measurements are useful in determining the local atomic environment of a particular element in a solid. Since there has been some controversy about the nature of the defects produced in A-15 materials by radiation damage, such studies were carried out on some A-15 compounds, V_3Ga which was damaged by neutrons, as well as Nb_3Ge damaged by 2.5 MeV a particles. In the V_3Ga sample, site exchange disorder seems to be the most important result of the neutron damage with less than 20% of the vanadium atoms on wrong sites. However, in the Nb_3Ge samples in addition to site exchange disorder, an unusual splitting of the first near-neighbor distance between the Ge and Nb is found. This splitting, approximately 0.2 A, may explain the large Debye Waller factors observed by Burbank et al.
Summary Status epilepticus or other brain-damaging insults launch a cascade of events that may lead to the development of epilepsy. MRI techniques available today, including T2- and T1-weighted imaging, functional MRI, manganese enhanced MRI (MEMRI), arterial spin labeling (ASL), diffusion tensor imaging (DTI), and phase imaging, can detect not only damage caused by status epilepticus but also plastic changes in the brain that occur in response to damage. Optimal balance between damage and recovery processes is a key for planning possible treatments, and noninvasive imaging has the potential to greatly facilitate this process and to make personalized treatment plans possible.
Initial rates of resistivity-measured low-temperature damage production by fission-spectrum fast neutrons have been determined for 14 metals in the same very well characterized irradiation facility. Six of these metals were fcc, 5 bcc, and 3 hcp. Most were of quite high purity. Observed damage rates, after correction for all known extraneous resistivity-producing effects, were compared with rates predicted by the damage calculation code RECOIL, using parameters chosen from the literature. These parameters, effective displacement threshold energy, E/sub d/, and Frenkel-pair resistivity, rho/sub F/, were in many cases only best estimates, the further refinement of which may be aided by the present results. Damage efficiencies (measured/predicted rates) follow the same trends by crystal classes as seen in other fast-neutron studies.
This paper focuses on a factorial-based design strategy. The approach provides an efficient and statistically reliable means for assessing the influence of multivariable effects. It is applied to the detection and evaluation of damage in impacted composite sandwich panels. The experimental results obtained from this test strategy are utilized to form an empirical response function. The resulting polynomial relates damage area to residual compression strength at values of independent variables for which testing did not occur. The response function also identifies nonlinear interaction effects of key variabes that cannot be easily ascertained by traditional single-variable test strategies. Independent variables evaluated include core thickness, number of face sheet plys and impact energy. The methodology presented allows the designer to predict with more confidence the damage tolerance of a composite material component, and ...
The topics of these short lectures on the subject of cyclic stress were: Microstructural mechanisms of damage accumulation under a multistage cyclic stress until incipient cracking; influence of surface decarbonizing phenomena on the failure behaviour of steel construction parts subjected to cyclic stress; thermocyclic fatigue of pipe samples of austenitic steel 1.4436; studies on surface structuring, microstructure and fatigue in LCF area. The short lectures on effects of quasi-static and creep stress were: Shear fracture in AlMg alloys as a result of local plastic instability; study of formation and growth of pores for an early recognition of damage and the course of damage in heat-resistant steels under creep test; experimental and numeric studies of the infuence of the microstructure on the course of damage during shear fractures of steel; numerical modelling of ductile fractures on the basis of ...
A 19.1 metre wind turbine blade was subjected to static tests. The purpose of the test series was to verify the abilities of different types of sensors to detect damage in wind turbine blades. Prior to each of the static test-series an artificial damage was made on the blade. The damage made for each test-series was surveyed during each series by acoustic emission, fiber optic micro bend displacement transducers and strain gauges. The propagation of the damage was determined by use of ultra sonic and X-ray surveillance during stops in the test series. By use of acoustic emission it was possible to measure damage propagation before the propagation was of visible size. By use of fiber optic micro bend displacement transducers and strain gauges it was possible to measure minor damage propagation. By use of both ultra sonic, and X-ray NDT-equipment it were possible ...
A unified physically based ion implantation damage model has been developed which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, BF{sub 2}, and boron implants into single-crystal silicon. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experimental measurements. This damage model is based on the physics of point defects in silicon, and explicitly simulates the defect production, diffusion, and their interactions which include interstitial-vacancy recombination, clustering of same type of defects, defect-impurity complex formation, emission of mobile defects from clusters, and surface effects for the first time. New computationally efficient algorithms have been developed to overcome the barrier of the excessive computational requirements. In ...
A unified physically based ion implantation damage model has been developed which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, BF_2, and boron implants into single-crystal silicon. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experimental measurements. This damage model is based on the physics of point defects in silicon, and explicitly simulates the defect production, diffusion, and their interactions which include interstitial-vacancy recombination, clustering of same type of defects, defect-impurity complex formation, emission of mobile defects from clusters, and surface effects for the first time. New computationally efficient algorithms have been developed to overcome the barrier of the excessive computational requirements. In addition, ...
Flow Accelerated Corrosion (FAC) of Carbon Steel (CS) piping has been one of main issues in Light-Water Nuclear Reactor (LWRs). Wall thinning of CS piping due to FAC increases potential risk of pipe rupture and cost for inspection and replacement of damaged pipes. In particular, corrosion products generated by FAC of CS piping brought steam generator (SG) tube corrosion and degradation of thermal performance, when it intruded and accumulated in secondary side of PWR. To preserve SG integrity by suppressing the corrosion of CS, High-AVT chemistry (Feedwater pH9.8#+-#0.2) has been adopted to Tsuruga-2 (1160 MWe PWR, commercial operation in 1987) in July 2005 instead of conventional Low-AVT chemistry (Feedwater pH 9.3). By the High-AVT adoption, the accumulation rate of iron in SG was reduced to one-quarter of that under conventional Low-AVT. As a result, a tendency to degradation of the SG thermal efficiency was improved. On the other hand, it ...
The condition of spent nuclear fuel (SNF) in wet storage at ten Soviet-designed research reactors has been assessed in the light of international experience in order to identify any associated safety issues. These reactors use Al-clad UO2-Al or U-Al alloy dispersion fuels of ?20% enrichment that were fabricated in Russia; the reactors have been in operation since 1955-70. Although originally sent for reprocessing, much of the SNF generated over the last 25-30 years has been stored in fuel storage pools (FSPs) of variable water quality. The external condition of wet-stored SNF assemblies from the reactors surveyed varied from significant failure due to galvanic corrosion that was driven by poor water quality, through gradual pitting caused by slightly impure water, to a stable condition of no observable change in the oxidized Al alloy surface of the irradiated fuel. SNF stability in wet storage seems to depend on three factors: Al being the sole metal in the FSP (to ...
Transient enhanced diffusion (TED) from implantation of 5thinspkeVthinspB{sub 10}H{sub 14} and 0.5 keV B ions has been quantified and compared for nominal boron doses of 10{sup 14} and 10{sup 15}thinspcm{sup {minus}2}. Boron diffusivity during annealing was extracted from secondary ion mass spectroscopy depth profiles of diffused marker layers in boron doping-superlattices and the actual implanted B dose was independently measured by nuclear reaction analysis. Comparable enhancements were observed from both ions. Transmission electron microscopy analysis revealed that both boron- and decaborane-implanted samples were amorphized at a nominal 10{sup 15}thinspcm{sup {minus}2}thinspB dose. A comparison with data from low energy Si implants revealed a similar dependence of diffusivity enhancement on implant dose. These findings are consistent with the understanding that TED is caused by the interstitial supersaturation resulting from a number of excess interstitials ...
Transient enhanced diffusion (TED) from implantation of 5keVB_1_0H_1_4 and 0.5 keV B ions has been quantified and compared for nominal boron doses of 10"1"4 and 10"1"5cm"-"2. Boron diffusivity during annealing was extracted from secondary ion mass spectroscopy depth profiles of diffused marker layers in boron doping-superlattices and the actual implanted B dose was independently measured by nuclear reaction analysis. Comparable enhancements were observed from both ions. Transmission electron microscopy analysis revealed that both boron- and decaborane-implanted samples were amorphized at a nominal 10"1"5cm"-"2B dose. A comparison with data from low energy Si implants revealed a similar dependence of diffusivity enhancement on implant dose. These findings are consistent with the understanding that TED is caused by the interstitial supersaturation resulting from a number of excess interstitials approximately equal to the number of implanted atoms which can become ...
During the Bruce A Nuclear Generating Station (BNGS-A) Unit 1 1997 planned outage, a dew point search method identified a leak in one steam generator(SG) tube. Subsequently, the tube was inspected with all available eddy current probes and removed for examination. The initial inspection results and metallurgical examination of the removed tube confirmed that the leak was due to intergranular attack/stress corrosion cracking (IGA/SCC) emanating from the secondary side of the tube at the top of the tubesheet location. Subsequently, eddy current and ultrasonic indications were found at the top of the tubesheet of other Alloy 600 SG tubes. To investigate the source of the indications and to validate the inspection probes, sections of 40 tubes with various levels of damage were removed. The metallurgical examination of the removed sections showed that both secondary side and primary side initiated, circumferential, stress corrosion cracking and ...
By 1970 the first edition of the ASME Code Section XI, Inservice Inspection of Nuclear Reactor Coolant Systems was published. From its inception, the Section XI inservice inspection scope was based on a fundamental risk-based selection process. In other words the inservice inspection scope included components where the consequences of a pressure boundary failure were high. Once the consequence significant system boundaries were established, inspections would then be performed at locations believed to be most susceptible service induced failure. Current Section XI requirements require that inspection locations be selected on the basis of peak stress and fatigue usage values contained in the Design Reports. These original stress calculations were designed to qualify a design and assure that the plant would provide reliable service throughout its design life. For the most part, the fatigue usage values in these reports do not provide an accurate measure of service ...
Piping systems transporting high-pressure fluid will release a large amount of energy, leading to whipping of the broken pipe as well as impingement of the ejecting fluids on adjacent structures if they fracture unstably. Postulation of such an event in design of piping systems in nuclear power plants often requires various counter measures such as installation of pipe whip restraints or jet impingement shields to prevent such damage. One of the approaches to justify exclusion of unstable fracture from the design conditions is leak-before-break (LBB) analysis. In order to demonstrate LBB behavior, it is necessary to prove that in the presence of a part-through wall flaw in the pipe, this flaw will not grow through the wall under fatigue loading and is stable (level 2 LBB) and that the leak of fluid through the penetration is detected by leak detection systems before unstable fracture occurs (level 3 LBB). If this can be demonstrated in plant ...
The research carried out in Canada in the design of containers for the disposal of radioactive waste has focussed on spent nuclear fuel, even though the quantities of other currently stored radioactive wastes are substantially greater. Research carried out at the Royal Military College of Canada on the effects of mixed fields of radiation on high polymer adhesives and composite materials has shown that some polymers are quite resistant to radiation and could well serve in the fabrication of radioactive waste disposal containers. The purpose of this research was to determine if thermoplastic polymers could be used as superior materials to replace metals in the application of low and intermediate level radioactive waste disposal containers. Polymers have the advantage that they do not corrode like metals. The experimental methods, used in this research, focused on the effects of radiation on the properties of the materials. Polypropylene, Nylon 66, Polycarbonate, and ...
Neuronal cell death induced by oxidative stress is correlated with numerous neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The causes of sporadic forms of age-related neurodegenerative diseases are still unknown. Recently, a correlation between paraquat exposure and neurodegenerative diseases has been observed. Paraquat, a nonselective herbicide, was once widely used in North America and is still routinely used in Taiwan. We have used differentiated Human Neuroblastoma (SHSY-5Y) cells as an in vitro model to study the mechanism of cell death induced by paraquat. We observed that paraquat-induced oxidative stress in differentiated SHSY-5Y cells as indicated by an increase in the production of cellular reactive oxygen species (ROS). Furthermore, apoptosis was evident as indicated by cellular and nuclear morphology and DNA fragmentation. Interestingly, pretreatment of SHSY-5Y cells with water-soluble Coenzyme ...
This paper summarizes results of preliminary experiments to develop cytological and biochemical indicators for estimating damage to respiratory cells in test animals exposed by inhalation to toxic agents associated with nonnuclear energy production, the specific goal being the application of advanced multiparameter flow-systems technologies to the detection of early atypical cellular changes in lung epithelium. Normal Syrian hamster lung cell samples composed of histiocytes, leukocytes, macrophages, ciliated columnar cells, and epithelial cells were stained with fluorescent dyes specific for different biochemical parameters and were analyzed in liquid suspension as they flowed through a chamber intersecting a laser beam of exciting light. Multiple sensors measured the total or two-color fluorescence and light scatter on a cell-by-cell basis. Cellular parameters proportional to optical measurements (i.e., cell size, DNA content, total protein, nonspecific esterase ...
The purpose of this Analysis and Model Report (AMR) supporting the Site Recommendation/License Application (SR/LA) for the Yucca Mountain Project is the development of elementary analyses of the interactions of a hypothetical dike with a repository drift (i.e., tunnel) and with the drift contents at the potential Yucca Mountain repository. This effort is intended to support the analysis of disruptive events for Total System Performance Assessment (TSPA). This AMR supports the Process Model Report (PMR) on disruptive events (CRWMS M&O 2000a). This purpose is documented in the development plan (DP) ''Coordinate Modeling of Dike Propagation Near Drifts Consequences for TSPA-SR/LA'' (CRWMS M&O 2000b). Evaluation of that Development Plan and the work to be conducted to prepare Interim Change Notice (ICN) 1 of this report, which now includes the design option of ''Open'' drifts, indicated that no revision ...
Large-scale field tracer experiments have been conducted on Ulchin, Wolsung and Daeduk sites for the purpose of validating FADAS and of analyzing the environmental characteristics around the nuclear sites. The most influential factor in atmospheric dispersion is the meteorological condition. During the experiment, meteorological data were measured on the release point and the selected positions among sampling points. Once radioactive materials are released to the atmosphere, members of public may be exposed through the environmental media such as air, soil and foods. Therefore, to protect the public, adequate countermeasures should be taken at due time for those exposure pathways. both processes, of justification and optimization are applied to a countermeasure simultaneously for decision-making. The work scope of Biological research for the radiation protection had contained the search of biological microanalytic methods for assessing the health effect by ...
Flow-induced vibration is an important concern to the designers of heat exchangers subjected to high flows of gases or liquids. Two-phase cross-flow occurs in industrial heat exchangers, such as nuclear steam generators, condensers, and boilers, etc. Under certain flow regimes and fluid velocities, the fluid forces result in tube vibration and damage due to fretting and fatigue. Prediction of these forces requires an understanding of the flow regimes found in heat exchanger tube bundles. Excessive vibrations under normal operating conditions can lead to tube failure. Relatively little information exists on two-phase vibration. This is not surprising as single-phase flow induced vibration; a simpler topic is not yet fully understood. Vibration in two-phase is much more complex because it depends upon two-phase flow regime, i.e. characteristics of two-phase mixture and involves an important consideration, which is the void fraction. The effect of ...
Korea Atomic Energy Research Institute, using the ANS Low Power /Shutdown (LPSD)PRA Standard, evaluated the LPSD PSA model of the KSNP, Younggwang (YGN) Units 5 and 6, and identified the items to be improved. The evaluation results of human reliability analysis (HRA) of the pre-accident human errors in the LPSD PSA model of the KSNP showed that 13 items among 15 items of supporting requirements for those in the ANS PRA Standard were identified as them to be improved. Thus, we newly carried out a HRA for pre-accident human errors in the LPSD PSA model for the KSNP to improve its quality. We considered potential pre-accident human errors for all manual valves and control/instrumentation equipment of the systems modeled in the KSNP LPSD PSA model except reactor protection system/ engineering safety features actuation system. We reviewed 160 manual valves and 56 control/instrumentation equipment. The number of newly identified pre-accident human errors is 101. Among them, the number of ...
Korea Atomic Energy Research Institute, using the ANS low power and shutdown (LPSD) probabilistic risk assessment (PRA) Standard, evaluated the LPSD PSA model of the KSNP, Yonggwang Units 5 and 6, and identified the items to be improved. The evaluation results of human reliability analysis (HRA) of the post-accident human errors in the LPSD PSA model for the KSNP showed that 10 items among 19 items of supporting requirements for those in the ANS PRA Standard were identified as them to be improved. Thus, we newly carried out a HRA for post-accident human errors in the LPSD PSA model for the KSNP. Following tasks are the improvements in the HRA of post-accident human errors of the LPSD PSA model for the KSNP compared with the previous one: Interviews with operators in the interpretation of the procedure, modeling of operator actions, and the quantification results of human errors, site visit. Applications of limiting value to the combined post-accident human errors. Documentation of ...
A working visit was made to the National Laboratory for High Energy Physics, Tsukuba, Japan, during the time periods May 16, 1988--June 15, 1988 for the purposes of further evaluation of the high intensity plasma sputter negative ion source and to test the response of the University of Tsukuba 13-MV tandem accelerator to mA intensity level pulsed mode heavy negative ion beams. During the visit, the traveler worked in collaboration with Japanese scientists in installing and testing of the source on the University of Tsukuba tandem electrostatic accelerator injector. During the course of preliminary testing of the ion source and prior to actual injection into the accelerator, sparking began in one or more tube sections, which ultimately led to the decision to replace the damaged tube sections. This problem led to postponement of the scheduled tandem accelerator tests. The traveler attended the Seventh International Conference on Ion Implantation Technology held in ...
We describe a model of damage in rf cavities and show how this damage can limit cavity operation. We first present a review of mechanisms that may or may not affect the ultimate fields that can be obtained in rf cavities, assuming that mechanical stress explains the triggers of rf breakdown events. We present a method of quantifying the surface damage caused by breakdown events in terms of the spectrum of field enhancement factors, Beta, for asperities on the surface. We then model an equilibrium that can develop between damage and conditioning effects, and show how this equilibrium can determine cavity performance and show experimental evidence for this mechanism. We define three functions that quantify damage, and explain how the parameters that determine this performance can be factored out and measured. We then show how this model can quantitatively explain the dependence of ...
The examples quoted show that damage is mostly due to faults of design and construction or faulty operation. The ever shorter development cycles, the further development of existing constructions and cost pressure owing to price slumps are very important in this context. Careful endoscopic inspections and monitoring and early identification of beginning damage helps to prevent major damage and follow-up damage. The causes of changing operational performance must be established as early as possible to prevent larger damages from being caused by continued operations.(orig.) [German] Die vorgestellten Schadenbeispiele zeigen, dass die Schaeden vorwiegend durch Auslegungsfehler und Konstruktionsfehler aber auch durch Bedienungsfehler verursacht wurden. Die immer kuerzeren Entwicklungszeiten fuer Neukonstruktionen und die Weiterentwicklung vorhandener Konstruktionen sowie der Kostendruck ...
Nuclear forensics is the analysis of nuclear materials recovered from either the capture of unused materials, or from the radioactive debris following a nuclear explosion and can contribute significantly to the identification of the sources of the materials and the industrial processes used to obtain them. In the case of an explosion, nuclear forensics can also reconstruct key features of the nuclear device. Nuclear forensic analysis works best in conjunction with other law enforcement, radiological protection dosimetry, traditional forensics, and intelligence work to provide the basis for attributing the materials and/or nuclear device to its originators. Nuclear forensics is a piece of the overall attribution process, not a stand-alone activity
In acute intoxication, uranium (U) not only inhibits bone formation but its excretion in urine also causes renal damage. The former effect is ameliorated by tetracycline (TC), probably due to its chelation property, which might also prevent U deposition in bone. Chemical determination of U incorporated in bone and a histological study of the kidneys were performed on animals injected with U and then treated with TC. The results showed that TC was unable to prevent the binding of U to bone while it exacerbated U-induced renal damage.
Numerical simulation of dynamic fracture of concrete slabs, impacted by steel projectiles, was carried out in this study. The concrete response was described by a continuum damage model. This continuum damage model was originally developed to study rock fragmentation and was modified in the present study with an emphasis on the post-limit structural response. The model was implemented into a transient dynamic explicit finite element code LS-DYNA2D and the code was then used for the numerical simulations. The specific impact configuration of this study follows the experiment series conducted by Hanchak et al. Comparisons between calculated results and measured data were made. Good agreements were found.
The influence of material configuration and impact parameters on the damage tolerance characteristics of sandwich composites comprised of carbon-epoxy woven fabric facesheets and Nomex honeycomb cores was investigated using empirically based response surfaces. A series of carefully selected tests were used to isolate the coupled influence of various combinations of the number of facesheet plies, core density, core thickness, impact energy, impactor diameter, and impact velocity on the damage formation and residual strength degradation due to normal impact. The ranges of selected material parameters were typical of those found in common aircraft applications. The diameter of the planar damage area associated with Through Transmission Ultrasonic C-scan measurements and the peak residual facesheet indentation depth were used to describe the extent of internal and detectable surface damage, respectively. ...
Apparent growth of amorphous layers during low temperature annealing was observed in low energy Ge{sup +}-implanted (0 0 1)Si by high-resolution transmission electron microscopy. The occurrence of abnormal growth is due to the randomization of heavily damaged regions beneath the original amorphous/crystalline interfaces. The randomization process is attributed to the strain, incurred by the presence of a high density of large Ge atoms in the heavily damaged Si substrate, relaxation to lower the free energy of the systems. The randomization upon annealing may be fruitfully applied to minimize the transient enhanced diffusion in shallow junction formation.
Apparent growth of amorphous layers during low temperature annealing was observed in low energy Ge"+-implanted (0 0 1)Si by high-resolution transmission electron microscopy. The occurrence of abnormal growth is due to the randomization of heavily damaged regions beneath the original amorphous/crystalline interfaces. The randomization process is attributed to the strain, incurred by the presence of a high density of large Ge atoms in the heavily damaged Si substrate, relaxation to lower the free energy of the systems. The randomization upon annealing may be fruitfully applied to minimize the transient enhanced diffusion in shallow junction formation.
This text-book (electronic book - multi-media CD-ROM) constitutes a course-book - author's collection of lectures. It consists of 13 lectures in which the reader acquaints with the basis of radiobiology: Introduction to radiobiology; Physical fundamentals of radiobiology; Radiation of cells; Modification of radiation damage of cells; Reparation of radiation damage of cells; Radiation syndromes and their modification; Radiation injury; Radiation damage of tissues; Effect of radiation on embryo and fetus; Biological effects of incorporated radionuclides; Therapy of acute irradiation sickness; Delayed consequences of irradiation; Radiation oncology and radiotherapy. This course-book may be interesting for students, post-graduate students of chemistry, biology, physics, medicine as well as for teachers, scientific workers and physicians. (author)
This paper describes examples of the damage resulting from the impact of a whipping pipe on a nearby pressurised pipe. The work is a by-product of a study of the motion of a whipping pipe. The tests were conducted with small-diameter pipes mounted in rigid supports and hence the results are not directly applicable to large-scale plant applications where flexible support mountings are employed. The results illustrate the influence of whipping pipe energy, impact position and support type on the damage sustained by the target pipe.
This paper describes examples of the damage resulting from the impact of a whipping pipe on a nearby pressurised pipe. The work is a by-product of a study of the motion of a whipping pipe. The tests were conducted with small-diameter pipes mounted in rigid supports and hence the results are not directly applicable to large-scale plant applications where flexible support mountings are employed. The results illustrate the influence of whipping pipe energy, impact position and support type on the damage sustained by the target pipe. (author).
Theoretical analysis, modeling, and simulation are used to provide insight into the development of permeability during thermal damage of the high explosive PBX 9501. In a recently published article, Terrones et al. [1] conclude that samples of PBX 9501 thermally damaged at 186 degreeC are not permeable to gas flow in a manner consistent with Darcys Law. We disagree with their conclusion. We show that they have misreported data from the literature, and that their argument depends on a fluid flow model that is physically incorrect and is applied with inappropriate physical parameters.
Nuclear forensics can provide information about the history, intended use and potentially the origin of nuclear or radioactive material. For these reasons, it is an important tool for improving nuclear security and combating illicit trafficking of nuclear and other radioactive materials. The IAEA is currently working on enhancing knowledge, techniques, procedures and cooperation in the field of nuclear forensics. Some of the work currently being undertaken by the IAEA includes the development of a five day training workshop on basic methods for radiological crime scene activities, to ensure adequate control of evidence, including for nuclear forensics purposes, a coordinated research project on the application of nuclear forensics in illicit trafficking, and a proposal for international cooperation with nuclear forensics ...
Despite a complex cascade of cellular events to reconstruct the damaged extracellular matrix, ligament healing results in a mechanically inferior scarred ligament. During normal healing, granulation...Full Text Available
Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and...Full Text Available
Elaboration of a Modern Technology for Operational Agrometeorological Soil Moisture Monitoring Spring Wheat, Yield and Disease Damage Forecasting and Recommendations for Plant Protection on the Kazakhstan Territory
Senescence is regarded as a physiological response of cells to stress, including telomere dysfunction, aberrant oncogenic activation, DNA damage, and oxidative stress. This stress response has an antagonistically...Full Text Available
The purpose of the recommendation is to prevent, to detect, and to remove soiling of guide and retrating blades of steam turbines, e.g. on account of foreign matter in steam dissolved. (TK/LN).
The kinetic energy transferred to some elements by an electron of kinetic energy 100 to 400 kV is discussed. The displacement rates are compared to the signal generation. (DCL)
Description: Hurricane Hugo, which struck South Carolina in September of 1989, destroyed a significant proportion of the State's timber. Primary wood-products ...
Rheumatoid arthritis (RA) is a debilitating autoimmune disease of global prevalence. The disease is characterized by synovial inflammation leading to cartilage and bone damage. Most of the conventional...Full Text Available
BackgroundAlterations in protein composition and oxidative damage of high-density lipoprotein (HDL) have been proposed to impair the cardioprotective properties of...Full Text Available
Shadow effect was used for investigating damage of uranium dioxide monocrystal. The dependence of shadow minimum parameters on fluence of "2"2Ne ions with 172 MeV energy was followed when detecting fission fragments. Ion dose responsible for sufficient microdamage of lattice structure, included into the classification of heavy ion damage effect on monocrystals was determined. The problem of radiation intensity effect on the character of occurred damages was studied. It was established that macroscopic sample failure, caused by generation of considerable mechanical stresses in monocrystal under beam effect could be observed along with microdamages of lattice structure at ion flux density >10"1"2 cm"-"2Xs"-"1.
The cost incurred every year in West Germany due to air pollution is investigated. Damage to buildings, materials, and vegetation are evaluated as well as the cost of additional cleaning work and changes of location with the objective of getting a picture of the economic value of air pollution abatement. The findings are based on data of immission damage in high-exposure areas. Damage is assessed in consideration of the frequency of repair measures in industrial and country atmosphere. Further research will be necessary in view of the many problems concerning methods and availability of basic statistical data. The sequential cost estimated for a few selected cases of damage show that economic losses due to air pollution amount to several thousand million DM. Air pollution abatement measures thus do not only improve our quality of life but also help to save considerable cost to our national economy.
The objectives of the Phase-I research address the development of mechanics- based structural integrity analysis methodologies for composite sandwich panels ...
Physiological bone remodeling is a highly coordinated process responsible for bone resorption and formation and is necessary to repair damaged bone and to maintain mineral homeostasis. In addition to...Full Text Available
Ultra-shallow junction formation in deep submicron Si devices is limited by anomalous diffusion of the dopant, which is related to the release of interstitials from defect clusters formed during the implantation of energetic ions or the subsequent annealing. The work described in this dissertation is concerned with the effects of low energy B ion implantation, especially damage formation, clustering and its annealing. After a review of the stopping and ranges of energetic ions in Si, the formation of implant damage, in particular of point defects, their migration, agglomeration and annihilation, including the involvement of dopant ions, is considered. A description of the Salford ultra low energy implanter is given and the main analysis technique, medium ion energy scattering (MEIS) reviewed. Additional analytical techniques used, such as secondary ion mass spectrometry (SIMS), 4-point probe and cross section transmission microscopy (XTEM) as ...
There is a lot of interest in the studies that would help to understand whether there is a casual association between cancer and various types of molecular or cytogenetic damage detected in human cells. One major oncogenesis process is activation of proto-oncogenes by point mutations or chromosomal translocation. There are substantial evidence that indicates that the loss of heterozygosity of certain chromosomes is involved in human cancerogenesis. Our study aimed to elicit the possible association between cancer and DNA and cytogenetic abnormalities induced in lymphocytes of people bearing various categories of skin cancer cells. Fresh blood was collected by venipuncture from 25 individuals (including nine prior to cancer treatment). All patients were nonsmoking males, however 42.3 % of them were former smokers. Blood samples were divided into two parts and in the first part of samples cytogenetic studies were performed immediately, while from the second part ...
Nuclear cloning is still a developing technique used to create genetically identical animals by somatic cell nuclear transfer into unfertilized eggs. Despite an intensive effort in a number...Full Text Available
Announced as the first of a series of annual reports on the spread of nuclear weapons, this endeavor of the Carnegie Endowment for International Peace may stimulate increased public awareness of this critical topic. A good part of the book contains the historical setting of the nuclear issue in the eight most likely proliferators.
Nuclear approaches for compositional characterization has bright application prospect in forensic perspective towards assessment of nature and origin of seized material. The macro and micro physical properties of nuclear materials can be specifically associated with a process or type of nuclear activity. Under the jurisdiction of nuclear analytical chemistry as well as nuclear forensics, thrust areas of scientific endeavor like determination of radioisotopes, isotopic and mass ratios, analysis for impurity contents, arriving at chemical forms/species and physical parameters play supporting evidence in forensic investigations. The analytical methods developed for this purposes can be used in international safeguards as well for nuclear forensics. Nuclear material seized in nuclear trafficking can be identified and a ...
National Nuclear Safety Department is authorized by Infra (Iranian Nuclear Regulatory Authority) for issuing rules and regulation and conducting the licensing and supervisory process for nuclear facilities. The main responsibilities of the NNSD are conducted via five main division are, nuclear codes and standards, Nuclear Safety assessment, Authorization, Inspection and Enforcement and Technical Support. In this paper, the functions and responsibilities of TSD in enhancing nuclear safety are described. Examples of main tasks to support the Nuclear Safety assessment division regarding to technical calculations and research of safety issues in licensing documents are provided. (author)
Techniques for studying nuclear structure are reviewed. Examples are given of charge density determinations by electron and proton inelastic scattering. (AIP)
Four topics in nuclear astrophysics, namely; pulsars, star evolution, nucleosynthesis and solar neutrinos are reviewed through the discussion of the observational data.
The measurements of the nuclear decay of actinide isotopes and the evaluation of the radioactive properties of nuclide with the mass 242 is discussed in this paper.
Since nuclear terrorism has been identified as a real threat, the Korean government has earnestly developed elementary technologies and sub-systems for establishing an integrated defensive system against nuclear terrorism, which is based on the concept of defense-in-depth. This paper introduces the gist and implications of the studies that have been conducted in building the national nuclear material tracking system for preventing and intercepting the illicit trafficking and transporting of nuclear material in Korea. (orig.)
A preliminary design for a nuclear engine is presented. The engine is based on the nuclear heating of a gas composed of H{sub 2} and {sup 242m}Am as a nuclear fuel. This engine has an initial volume of 0.135 m{sup 3} and at 64 MPa the critical mass is 0.228 kg. The simplicity {sup 242m}Am of the engine design might compensate for the use of rare nuclear fuel, such as {sup 242m}Am.
Although the p53 tumor suppressor is relatively well characterized, much less is known about the functions of other members of the p53 family, p73 and p63. Here, we present evidence that in specific pathological conditions caused by exposure of normal cells to bile acids in acidic conditions, p73 protein plays the predominant role in the DNA damage response. These pathological conditions frequently occur during gastric reflux in the human esophagus and are associated with progression to esophageal adenocarcinoma. We found that despite strong DNA damage induced by bile acid exposure, only p73 (but not p53 and p63) is selectively activated in a c-Abl kinase-dependent manner. The activated p73 protein induces DNA damage repair. Using a human DNA repair PCR array, we identified multiple DNA repair genes affected by p73. Two glycosylases involved in base excision repair, SMUG1 and MUTYH, were characterized and found to be ...
BackgroundThe Mre11/Rad50/Nbs1 (MRN) complex is a regulator of cell cycle checkpoints and DNA repair. Defects in MRN can lead to defective S-phase arrest when cells are damaged....Full Text Available
A simple model is used to explain the decrease in superconducting critical temperature with damage observed for irradiated A-15 compounds. A truncated t-matrix approximation is used to describe the disorder along the one-dimensional transition metal chains. Three dimensionality is introduced by the inclusion of interaction between transition metal atoms on different chains. Numerical fits to experiment are discussed in the conclusion. (author).
The resistance to microbe damages of aqueous solutions of cutting fluids (SOZh), which contain dual and more complex mixtures of known compounds, is studied. Lauric acid, myristic and tridecanic acid give microbic resistance to the compositions of synthetic cutting fluids. A complexing of the compositions as a rule does not support precisely expressed effects of synergism or antagonism.
Full text: It is known that the ion implantation of germanium single crystals at room temperature results in drastic alteration of the germanium surface and the formation of cellular relief. Voids were found into the near-surface damage layer. The intersection of these voids with the germanium surface, as result of sputter etching, forms cellular relief. However, exact mechanism responsible for formation of the voids is not known. A 10 and 30 keV Ga"+ irradiation of Ge #left brace#100#right brace# crystal at room temperature was carried out using a focused ion beam (FIB) system with a dose in the range 0.5x10"1"2 to 1.5x10"1"4 ion/cm"2. The topology of the modified germanium surface and the structure of the radiation damage was studied using imaging facilities of the FIB systems and transmission electron microscopy. The strong cellular structure of Ge was observed after an ion dose of 3x10"1"3 ion/cm"2. High-resolution TEM showed a complex ...
Allianz Global Corporate and Specialty AG, the industrial insurance carriers of Allianz Group and AZT Risk and Technology GmbH, have a lot of experience and a comprehensive database about damage of industrial steam turbines and large-scale power generation turbosets. Sound maintenance concepts are the main loss prevention measure, which will be presented and discussed in detail. Some modifications and additions to existing maintenance concepts are also provided.
Blades of modern steam turbines are designed for high efficiency and operational safety. Modern computer programs enable optimisation of design but factors like manufacturing, assembly, operation and downtimes still play an important role. Damage statistics show that blade damage still quite frequent. Selected cases from the Allianz damage assessment centre show some of the more frequent damage mechanisms. Damage is often caused when several factors come together. Prevention of follow-up damage requires early identification of beginning damage.(orig.) [German] Die Auslegung der Beschaufelung moderner Dampfturbinen hat die Vorgabe, einen hohen Wirkungsgrad bei gleichzeitig hoher Betriebssicherheit zu erreichen. Mit den heute zur Verfuegung stehenden Rechenprogrammen ist eine entsprechende Optimierung realisierbar. Fuer die langzeitige ...
The histone chaperone Asf1 and the chromatin remodeler SWI/SNF have been separately implicated in derepression of the DNA damage response (DDR) genes in yeast cells treated with genotoxins that cause...Full Text Available
From the frequency of diagnostic radiologic examinations and their radiation dose delivered to the population the risk of cancer induction and genetic damage is calculated on the basis of the risk factors given by the ICRP. Thus 0.38 % and 3 % of the total mortality for cancer and leukemia, resp., can be attributed to X-ray diagnostics. Chest examinations alone result in 0.07-0.7 damages per 100,000 persons depending on the imaging technique applied. (author).
Substantial damages at main components of steam turbines do not have to result inevitably in an exchange of the components concerned. Rather a preliminary or final repair is possible which also considers the cause of the damage. An important condition with the technically complex questions is an appropriate qualification and experience of all involved persons. The common task of operators, manufacturers and insurance companies is to preserve the balance from costs, expenditure of time and risk.
sinensis), the otter (Lutra lutra) and the grey seal (Halichoerus grypus) can be mentioned as ...conflict relates to damage caused by the grey seal to coastal fisheries, whereas in Germany damages ...For example species like the grey seal involved in the conflicts may benefit from the by-catch regulation.
Specifications of the PGV-1000 steam generators applied at the WWER-1000 NPP power units, operational experience and data on damages at the 'cold' heat carriers of steam generators are considered and their results are presented. Developed and introduced measures aimed at improving reliability and operational life of the PGV-1000 collectors are described.
This book examines the nonlinear optical properties of laser materials. The physical radiation effects on laser materials are also considered. Topics considered include: nonlinear optical properties; nonlinear and harmonic generation materials; two-photon absorption; nonlinear refractive index; stimulated Raman scattering; radiation damage; crystals; and glasses.
Late somatic and genetic radiation effects are imperfectly understood, particularly in the human species. However the available information is sufficient to draw reasonably precise risk estimates in man for many types of damage by means of scientifically justifiable procedures and with the necessary caution. This overall absolute risk of major somatic and genetic damage may be set at around 10"-"4/rad of chronic whole-body doses.
The overall objective of this project is to produce antibodies to unique modified DNA bases and develop immunochemical assays to quantitate these lesions in damaged DNA. During this past year we have developed an antibody and chemical test to quantitate a basic sites in DNA and produced antibodies to the 8-oxopurines. This report discusses the detection of a basic sites in DNA and the preparation of antibodies to 8-hydroxyadenine and 8-hydroxyguanine.
Surface barrier detectors may be damaged, because of microplasma breakdown, in rapid application of bias voltage. The high performance FETs of very low noise preamplifiers may also be damaged by rapid changes of the bias voltage. The electronic device described permits the gradual application and removal of the bias voltage, without any influence on the power supply specification. (Auth.).
The developed countries are implementing a policy minimizing damage from environmental pollution by reducing discharge in advance as well as the aftermath of a pollutant. The typical example is to use BAT (Best Available Technology). This is to prevent environmental damage by reducing the discharge of pollutants with available technology and to secure environmental margin to enable industrial activities of future generation. Therefore, the feasibility of introducing BAT requirement system was reviewed by considering foreign examples and Korean situation. 38 refs., 8 figs., 69 tabs.
The influence of high temperature thermal ageing treatments on the development of intercrystalline creep damage in two variants of Alloy 800 has been investigated. Ageing up to 3000 h and creep testing were carried out at 800 and 900 C. The high temperature behaviour of the 800HT variant is discussed with reference to the effect of heat treatments on the microstructure. The metallographic methods by which the creep damage was quantitatively determined are described. The growth rate of intercrystalline microcracks was described using a statistical model and the dependence of crack growth rate on the thermal history for both 800HT and 800H was determined. The carbide precipitation and growth processes were determined as functions of the exposure temperature and duration. The results showed the three characteristic stages, precipitation, growth and coarsening (Ostwald ripening). The largest increase in the intergranular creep ...
The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on ...
The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on ...
High energy piping systems are operated with either or both conditions of maximum operating temperature exceeding 200 .deg. F(93.3 .deg. C) or maximum operating pressure exceeding 275 psig(19.3kg/cm{sup 2}) during normal operating conditions in nuclear power plants. A high energy pipe failure is postulated in branches or piping that runs larger than one inch nominal diameter. The resultant consequences of these postulated pipe breaks must be analyzed for the effect on maintenance of plant safe shutdown capability, containment integrity. And the analyzed results must be applied to the system design so that a pipe failure can not damage essential systems to an extent of impairing design function nor affect necessary component operability. The considerable effects of pipe break are as follows; dynamic effects such as pipe whip, jet impingement and environmental impact by release of system contents. Two types of forces are occurred by the pipe ...
The paper is devoted to analysis of Russian nuclear education system: its current status, specific features, difficulties and prospects. Russian higher education system in nuclear engineering has been created simultaneously with the development of nuclear industry, and the system completely satisfied all industrial demands for the specialists of different qualification levels. For the past several decades, nuclear education has lost its attractiveness to young people. The paper discusses the actions to be undertaken for reversing the situation. The paper underlines particularly the special role of international collaboration and all-European integration of nuclear educational programmes for further development of nuclear education all over the world. (author)
Nuclear forensics aims at identifying origin and intended use of nuclear material using information inherent to the nuclear material.The information gathered in nuclear forensics include isotopic composition, elemental composition, impurities and age of the material, macroscopic appearance and microstructure. The information so collected helps to solve criminal cases and put the individuals involved in nuclear trafficking in jails. The information also helps to improve safeguards and physical protection measures at place of theft or diversion to prevent future thefts or diversions.
This talk reviews the history of the Canadian nuclear-electric program highlighting Canada's first nuclear power station, the Nuclear Power Demonstration or NPD. NPD was commissioned and delivered electricity to Canadian consumers for the first time on june 4, 1962. The Canadian nuclear-electric program is based on the CANDU-PHW (Canadian Deuterium Uranium - Pressurized Heavy Water) concept which was conceived between 1955 and 1958 at the Chalk River Nuclear Laboratory (CRNL) of AECL, located a few miles from Deep River. This talk covers the history of the Canadian nuclear-electric activities dating back to 1939.
Commercial focused ion beam (FIB) systems are commonly used to image integrated circuits (ICS) after device processing, especially in failure analysis applications. FIB systems are also often employed to repair faults in metal lines for otherwise functioning ICS, and are being evaluated for applications in film deposition and nanofabrication. A problem that is often seen in FIB imaging and repair is that ICS can be damaged during the exposure process. This can result in degraded response or out-right circuit failure. Because FIB processes typically require the surface of an IC to be exposed to an intense beam of 30--50 keV Ga{sup +} ions, both charging and secondary radiation damage are potential concerns. In previous studies, both types of effects have been suggested as possible causes of device degradation, depending on the type of device examined and/or the bias conditions. Understanding the causes of this damage is ...
The United States Government (USG) first developed nuclear forensics-related capabilities to analyze radiological and nuclear materials, including underground nuclear test debris and interdicted materials. Nuclear forensics is not a new mission for Department of Defense (DoD). The department's existing nuclear forensics capability is the result of programs that span six (6) decades and includes activities to assess foreign nuclear weapons testing activities, monitor and verify nuclear arms control treaties, and to support intelligence and law enforcement activities. Today, nuclear forensics must support not only weapons programs and nuclear smuggling incidents, but also the scientific analysis and subsequent attribution of terrorists' use of radiological or nuclear ...
It is important for the trauma surgeon to understand the basic principles of terminal gunshot ballistics and the study of the projectile's effect on striking soft tissue. The amount of kinetic energy dissipated to the tissue is directly related to the mass and velocity of the projectile as follows: K = MV2/2. Doubling the velocity quadruples the energy, while doubling the mass only doubles the energy. A temporary tissue cavity is produced as the striking projectile compresses the surrounding tissue; the higher the energy release, the more extensive the inapparent compressive damage. The permanent cavity that remains is the result of extrusion of tissue from the pathway of the projectile. The higher the velocity, the higher the likelihood of extensive damage. If the missile expands or fragments within the tissues, more damage will occur. PMID:6847483
Eugenol, the principal chemical component of clove oil from Eugenia aromatica has been long known for its analgesic, local anesthetic, anti-inflammatory, and antibacterial effects. The interaction of the eugenol with ten different hydrophobic and hydrophilic antibiotics was studied against five different Gram negative bacteria. The MIC of the combination was found to decrease by a factor of 5-1000 with respect to their individual MIC. This synergy is because of the membrane damaging nature of eugenol, where 1mM of its concentration is able to damage nearly 50% of the bacterial membrane. Eugenol was also able to enhance the activities of lysozyme, Triton X-100 and SDS in damaging the bacterial cell membrane. The hydrophilic antibiotics such as vancomycin and b-lactam antibiotics which have ...
Plastic injection molds are an important economic sector due to the increasing use of injection molded plastic components. The selection of mold steel material, its processing conditions, and the way it is machined and hardened all have an impact on how it performs during use across its lifecycle for injection molding. For this study, injection molding conditions seen during high volume manufacturing were used to induce wear that would be typical during processing. A 50wt.% glass fiber reinforced Polybutylene Terephthalate (PBT) was used for the research. After 3000 injection operations, surface damage was found only on the steel used for the stationary half of the mold cavity and the corresponding surface of the molded parts. In contrast, the moving half showed no surface damage or increa...
Scanning spreading resistance microscopy (SSRM) has been applied to study focused ion beam (FIB) induced damage in silicon in dependence on ion irradiation doses from 10"1"2 cm"-"2 to 2#centre dot#10"1"6 cm"-"2. Starting from the lowest dose, SSRM detects increasing spreading resistance (SR) with increasing dose. For doses from 2#centre dot#10"1"3 cm"-"2 to 4#centre dot#10"1"4 cm"-"2, a slight decrease of SR is measured whereas for higher doses SR again slightly increases. The results are explained by physical effects like decreased carrier mobility due to increased scattering, amorphisation of silicon and precipitation of implanted Ga ions. The results clearly prove that SSRM is well suited for the fast detection of ion beam induced damage with high lateral resolution.
Aims: Rapamycin (sirolimus) is an antibiotic that inhibits protein synthesis through mammalian targeting of rapamycin (mTOR) signaling, and is used as an immunosuppressant in the treatment of organ rejection in transplant recipients. Rapamycin confers preconditioning-like protection against ischemic-reperfusion injury in isolated mouse heart cultures. Our aim was to further define the role of rapamycin in intracellular Ca^2^+ homeostasis and to investigate the mechanism by which rapamycin protects cardiomyocytes from hypoxic damage. Main methods: We demonstrate here that rapamycin protects rat heart cultures from hypoxic-reoxygenation (H/R) damage, as revealed by assays of lactate dehydrogenase (LDH) and creatine kinase (CK) leakage to the medium, by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-d...
Nano photonic materials are synthetically manufactured crystals at the nano scale with the target of creating a microstructure with a special electro-magnetic periodicity. Such nano photonic materials have the ability to control light propagation and thus are capable of creating photonic bandgaps in the frequency domain. We propose using nano photonic crystals as sensors to detect microdamage in composite materials. We demonstrate using a simulation model that a nano photonic sensor attached to a composite bar experiences a significant change in its bandgap profile when damage is induced in the composite bar. The model predicts the frequency response of the nano photonic sensor using the transfer matrix method. A damage metric to evaluate the change in the frequency response is developed. Successful developments of nano photonic sensors allow damage identification at scales not attainable using current sensing technologies.
Specimen damage and element loss induced by 3 MeV proton and 2 MeV alpha particle bombardment of thin sections of freeze-dried kidney tissue and embedding medium have been studied. Yields of ions scattered from H and C, and characteristic X-rays were measured versus accumulated charge, for curent densities in the range from 8x10{sup -15} to 1.1x10{sup -11} A/{mu}m{sup 2}. Structural damage, dissolouration and loss of S, Cl, C and H have been observed. Implications of this study for ion beam microanalysis of biological tissues are discussed with particular reference to the results for H loss. (orig.).
The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 x 10{sup 14} cm{sup -2}) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure.
The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 x 10"1"4 cm"-"2) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure.
Abstract Background and Purpose: During laser lithotripsy, working instruments are often in close proximity to the distal fiber tip and may be damaged accidentally or even intentionally. The aim of this study was to compare the amount of damage to a standard guidewire and the nitinol wires of endourologic retrieval baskets that were affected by three different clinically available laser systems. Materials and Methods: The impact of pulsed laser irradiation on a standard hydrophilic guidewire and a retrieval basket were investigated. One infrared (IR) laser system (holmium:yttrium-aluminum-garnet [Ho:YAG]: ????=???2100???nm) and two laser systems emitting light in the visible (VIS) spectral range (frequency-doubled double-pulse neodymium:YAG [FREDDY]: ????=???532???nm/1064???nm and flashl...
The detection and characterization of deeply buried fatigue damage in thick, multi-layer airframe components pose significant technical challenges to the aviation safety community. Currently, no nondestructive evaluation technique is available to reliably detect such potential damage from the exterior of the airframe, which is highly desirable in light of inspection cost as well as avoidance of structure damage. Recent technological advances in high-sensitivity magnetic sensors, i.e., spin-dependent tunneling (SDT) sensors, make it feasible to employ electromagnetic inspection techniques for deep fatigue crack inspection. In this work, we report on the development and fabrication of a low frequency eddy current probe based on a magnetically shielded SDT pickup sensor concentrically located...
Phreatic groundwater pumping is affecting water availability for crops in areas with a shallow water table. This can reduce crop growth and so affect farm income. There is a need for a generic and transparent method to assess the agricultural damage caused by water table drawdown. This paper proposes such a method that consists of 'damage tables' relating agricultural production losses to the groundwater regime for different soil/crop combinations found in Northern Belgium. The damage tables are constructed based on numerous simulations with the agrohydrological model SWAP, in which the bottom boundary conditions are gradually changed to reflect different groundwater regimes. The credibility of the resulting metamodel is assessed in three ways: using (1) field data, (2) an existing local e...
In the flood surveys, it is fundamental to set up the relations of stage-damage. And this makes it possible to evaluate the flood regulation effects of the multipurpose dam and/or levee construction for optimum formulation. Unfortunately in the previous basin studies excluding the Han river basin survey, the conventional approaches on this matter have not been performed due to its time-consuming complexity. In this study we attempted a new method based on the disaster status, and constructed six stage-damage curves along the reaches of the Kum river basin, based upon the flood events records for recent 12 years (1981-92). (author). 12 refs., 3 tabs., 13 figs.
Microstructural observations of damage around indentations in Ti{sub 3}SiC{sub 2} are presented. The Vickers hardness decreased with increasing load and asymptotically approached 4 GPa at the highest loads. No indentation cracks were observed even at loads as high as 300 N. Preliminary strength versus indentation plots indicate that, at least for the large-grained material ({approx}100 {micro}m) studied here, Ti{sub 3}SiC{sub 2} is a damage-tolerant material able to contain the extent of microdamage to a small area around the indent. The following multiple energy-absorbing mechanisms have been identified from scanning electron micrographs of areas in the vicinity of the indentation: diffuse microcracking, delamination, crack deflection, grain push-out, grain pull-out, and the buckling of individual grains.
Pro-inflammatory cytokines may directly influence the viability and metabolic function of colonic epithelial cells (CEC) as an early event in the development of inflammatory bowel disease. We report here that TNF-alpha+IFN-gamma induced a synergistic, concentration-dependent decline in butyrate oxidation, an essential energy supply, in HT-29 and DLD-1 cells. TNF-alpha+IFN-gamma induced a parallel profound decline in cell viability in HT-29 cells, but not in DLD-1 cells, where impairment of butyrate oxidation seemed to precede later occurrence of cell damage. TNF-alpha+INF-gamma induced CEC damage was independent on NO formation and involved the IFN-gamma signalling pathway as well as induction of apoptosis. If cytokines have similar effects in vivo, these may lead to energy deficiency and thus contribute to CEC damage and disturbance of the epithelial integrity.
The effects of focused-ion-beam-induced damage on electrical properties of n-type Si are investigated by Schottky contacts. Crystalline Si is exposed to 10-30 keV focused ion beam (FIB), followed by Pt deposition under vacuum of 4x10"-"4 Pa. From current-voltage-temperature measurements, barrier heights of the Schottky contacts are found to increase almost linearly as the FIB energy increases, with the maximum increment of 0.29 eV. The increase is suggested to be related to the arising of acceptorlike defects and an amorphous layer due to FIB damages. A theoretical model is set up to quantitatively describe the barrier height changes.
Channeling effect measurements have been employed to investigate radiation damage produced by 100-keV Ar ions in preferred oriented polycrystalline metal-silicide layers, such as Pd/sub 2/Si and NiSi/sub 2/ layers formed on single-crystalline Si. For room-temperature implantation, an amount of the damage in Pd/sub 2/Si layers was found to saturate at doses between 3 x 10/sup 14/ and 1 x 10/sup 17/ ions/cm/sup 2/, where the minimum aligned yield of 1.5-MeV He ions was nearly 40% of the random one. On the contrary, it was observed that the NiSi/sub 2/ layers became amorphous at doses higher than 3 x 10/sup 15/ ions/cm/sup 2/. These results were confirmed by the reflection electron diffraction analyses.
Channeling effect measurements have been employed to investigate radiation damage produced by 100-keV Ar ions in preferred oriented polycrystalline metal-silicide layers, such as Pd_2Si and NiSi_2 layers formed on single-crystalline Si. For room-temperature implantation, an amount of the damage in Pd_2Si layers was found to saturate at doses between 3 x 10"1"4 and 1 x 10"1"7 ions/cm"2, where the minimum aligned yield of 1.5-MeV He ions was nearly 40% of the random one. On the contrary, it was observed that the NiSi_2 layers became amorphous at doses higher than 3 x 10"1"5 ions/cm"2. These results were confirmed by the reflection electron diffraction analyses.
We present results of multiple-time-scale simulations of 5, 10 and 15 keV low temperature ion implantation of arsenic on silicon (100), followed by high temperature anneals. The simulations start with a molecular dynamics (MD) calculation of the primary state of damage after 10ps. The results are then coupled to a kinetic Monte Carlo (MC) simulation of bulk defect diffusion and clustering. Dose accumulation is achieved considering that at low temperatures the damage produced in the lattice is stable. After the desired dose is accumulated, the system is annealed at 800 degrees C for several seconds. The results provide information on the evolution for the damage microstructure over macroscopic length and time scales and affords direct comparison to experimental results. We discuss the database of inputs to the MC model and how it affects the diffusion process.
The major degradation mechanisms acting during the aging of selected WWER-440/213 primary circuit facilities were assessed critically. The analysis gave evidence that such mechanisms include radiation and fatigue damage of the reactor pressure vessel (effect of the neutron flow, cyclic fatigue promoted by the corrosive medium, effect of thermal aging), corrosion-mechanical and thermo-mechanical (fatigue) damage of the steam generator (stress corrosion cracking, erosion corrosion, thermal aging, wear), thermal and dynamic aging of the pressurizer, and corrosion-mechanical damage of the primary circuit piping (thermal aging, corrosion). (J.B.). 5 tabs., 1 fig., 62 refs.
"9"9"mTechnetium -heat damaged erythrocyte were used as spleen scanning agents in 12 patients from July, 1985 to April, 1986. We used this scan to evaluate situs inversus, asplenia, accessory spleen, hypersplenism, splenic infarction, tumor staging and evaluation of therapy, especially when the "9"9"mTc-tin colloid scans were not definite for diagnosis. The techniques applied to these scans were in vivo/in vitro-labeling method and heating-method to damage the erythrocytes. Liver-to-spleen uptake ratios were increased upto 100:1 and interference from the left lobe of the liver was eliminated. These scans were helpful to evaluate the spleen. (Author).
The utilization of electrically heated rods for the simulation of nuclear fuel rods represents an universally adopted method by the nuclear industry to study thermalhydraulic problems. The present work represents the development of a method to obtain the time variation of the electric linear power necessary to simulate a given nuclear power transient in order to yield the same temperature and heat flux conditions in the surface of the electrical heater that would be obtained by the nuclear fuel rod. (Author).
The report is an overview on the production of the nuclear energy all over the world. The amount of production at present and in future, availability of the nuclear fuel, development of nuclear technology, environmental and safety issues, radioactive waste management and commissioning of the plants and also the competitivity of nuclear energy compared with other energy forms are considered. (91 refs.).
The results of the six meetings in the years 1976 through 1981 of the Panel on Reference Nuclear Data is reviewed, as well as the results of other studies and workshops. A brief review of how current programs are meeting the expressed nuclear data needs of professional groups is also presented. The types of data included in the review are reaction cross sections, isotopic abundances, atomic masses, nuclear structure, radioactive decay, and fission.
The general requirements applicable to the quality assurance of the Finnish nuclear power plants are presented in the Council of State Decision (395/91) and in the guide YVL 1.4. This guide specifies the quality assurance requirements to be applied during the operation of the nuclear power plants as well as of the other nuclear facilities. Quality assurance applies to all the activities and organizations with a bearing on the safe operation of the nuclear power plants. (5 refs.).
The use of nuclear reactors to provide electrical energy has shown considerable growth since the first nuclear plant started commercial operation in the mid 1950s. Although the main purpose of this paper is to review the fuel cycle capabilities in the United States, the introduction is a brief review of the types of nuclear reactors in use and the world-wide nuclear capacity.
The uncertainties of growth in Croatian future energy, particularly electricity demand, together with growing environmental considerations and protection constraints, are such that Croatia needs to have flexibility to respond by having the option of expanding the nuclear sector. The paper deals with nuclear energy as an option for croatian sustainable economic development. The conclusion is that there is a necessity for extended use of nuclear energy in Croatia because most certainly nuclear energy can provide energy necessary to sustain progress. (author).
A review of recent work in nuclear physics is presented. The paper gives a broad discussion of research goals in nuclear structure, quark-gluon degrees of freedom, quark-gluon plasma, symmetries, and rare decays. (DWL)
Second Regional Meeting for Nuclear Energy in Central Europe is an annual meeting of the Nuclear Society of Slovenia. The proceedings contains 75 articles from Slovenia, surrounding countries and countries of the Central and Eastern European Region
The article gives a brief description of the state of the nuclear power engineering in Ukraine and in the world as of today. There are basic organizational and practical actions on scientific and technical maintenance of the Ukraine nuclear power complex presented in the article.
This chapter provides an overview of the problem of response to a nuclear weapon accident, the fundamentals of response to an accident, and a summary of the NARP Manual. The manual provides a summary of procedural guidance, technical information, and DoD responsibilities, to assist DoD forces in preparing a response to a nuclear weapon accident.
The scope of our problems with nuclear waste management is outlined. Present and future inventories of nuclear wastes are assessed for risk. A discussion of what is presently being done to solve waste management problems and what might be done in the future are presented. (DC)
The number of nuclear pore complexes (NPCs) in individual nuclei of the yeast Saccharomyces cerevisiae was determined by computer-aided reconstruction of entire nuclei from electron...Full Text Available
Evaluated nuclear structure and decay data for all nuclei within the A = 203 mass chain are presented. This work supersedes the earlier evaluation by S. Rab (1993Ra11), published in Nuclear Data Sheets 70, 173 (1993).
A brief description of the physical process of dose enhancement effects produced by X-ray radiation on materials is given, with emphasis on the influence on electronic devices. The damages caused by X-ray radiation dose enhancement is more serious than that of #gamma#-ray with higher energy.
Exercise training is known to induce an increase in free radical production potentially leading to enhanced muscle injury. Vitamins C and E are well known antioxidants that may prevent muscle cell damage....Full Text Available
It is estimated that approximately a quarter of patients undergoing coronary intervention may have significant post-procedural creatinine (CK)/creatinine kinase myocardial band (CK-MB) elevations and...Full Text Available
The astonishingly efficient location and excision of damaged DNA bases by DNA repair glycosylases is an especially intriguing problem in biology. One example is the enzyme uracil DNA glycosylase (UNG),...Full Text Available
The oxidative stress theory of aging predicts that manipulations that alter oxidative stress/damage will alter aging. The gold standard for determining whether aging is altered is lifespan,...Full Text Available
Accessory cusp present on the occlusal surface may seldom pose problems. While its presence may not be a cause for alarm in most instances, it can sometimes lead to serious consequences if it is damaged....Full Text Available
Al2O3-based ceramic is one of the most widely used materials for tools employed in hardened steel turning applications due to its high hardness, wear resistance, heat resistance and chemical stability. The objective of this work is to predict the lives of Al2O3-(W, Ti)C ceramic tools in intermittent turning of hardened AISI 1045 steel by means of damage evolution model taking into account the mechanical loading and thermal effect in the cutting process. A damage evolution model analyzing the RVE with uniformly distributed interacting cracks is constructed based on micromechanics. The calculated results of the proposed damage evolution model are compared with the lives of two kinds of Al2O3-(W, Ti)C ceramic tools obtained through experiments. It is found that the proposed model can be used to predict the lives of the ceramic cutting tools in intermittent turning operation.
Thin film solar cells and solar cell testing - photovoltaic cells, radiation damage to cadmium sulfide solar cells, and airplane testing of solar cells
DNA double-strand breaks (DSBs) and other lesions occur frequently during cell growth and in meiosis. These are often repaired by homologous recombination (HR). HR may result in the formation of DNA...Full Text Available
FRAXA is one of a number of fragile sites in human chromosomes that are induced by agents like fluorodeoxyuridine (FdU) that affect intracellular thymidylate levels. FRAXA coincides with a >200...Full Text Available
Reactive oxygen species (ROS), inevitable byproducts of aerobic metabolism, are known to cause oxidative damage to cells and molecules. This, in turn, is widely accepted as a pivotal determinant of...Full Text Available
Domestic, low-level exposure to radon gas is considered a major environmental lung-cancer hazard involving DNA damage to bronchial cells by α particles from radon progeny. At domestic exposure...Full Text Available
Damaging inflammation arising from autoimmune pathology and septic responses results in severe cases of disease. In both instances, anti-inflammatory compounds are used to limit the excessive...Full Text Available
Total thyroidectomy involving the adjacent structures of the trachea can cause tracheal damage such as early tracheal necrosis. The authors describe the first case of anterior tracheal necrosis following...Full Text Available
4-Hydroxynonenal (HNE), a major electrophilic product of lipid peroxidation, is regarded as both a marker of oxidative stress and a mediator of oxidative damage. At subtoxic concentrations,...Full Text Available
In order to maintain a safe operation and availability of generating facilities, qualitative and quantitative assessment of piping vibration was performed vibration sources and damages of piping support was identified on the second piping system of Wolsun...
Experiments on Xanthium leaf discs were carried out to determine whether concomitant photoreactivation could be detected and if so, to compare its effects with photoreactivation due...Full Text Available
More than 30 years ago, human beings looked back from the Moon to see the magnificent spectacle of Earth-rise. The technology that put us into space has since been used to assess the damage...Full Text Available
Acetaminophen (N-acetyl-para-aminophenol (APAP), paracetamol) is a commonly used analgesic and antipyretic agent. Although considered safe at therapeutic doses, accidental or intentional...Full Text Available
Revised neutron fluence and damage values are reported for the MOTA-2A experiment in the Fast Flux Test Facility (FFTF). This revision corrects an error with processing of the {sup 235}U(n,f) reaction. Net corrections are on the order of 5%.
Using plasma glutathione S-transferase measurements hepatocellular integrity was assessed in groups of hyperthyroid and hypothyroid patients before and after treatment. Ten of 14 hyperthyroid patients...Full Text Available
Exact anatomic knowledge about the location of the gonads and the application of corresponding measures of radiation protection are the preconditions for an efficient reduction of the danger of a possible genetic damage as a result of radiation exposition during X-ray examination of the hip joint of newborns. (VJ).
The widely accepted oxidative stress theory of aging postulates that aging results from accumulation of oxidative damage. Surprisingly, data from the longest-living rodent known, naked mole-rats [MRs;...Full Text Available
It has been sixty years since the Millers first described the covalent binding of carcinogens to tissue proteins. Protein covalent binding was gradually overshadowed by the emergence of DNA...Full Text Available
Gonadal function was studied in two groups of children previously treated for medulloblastoma with surgery followed by postoperative craniospinal irradiation. In group 1 but not in group 2, the children also received adjuvant chemotherapy for one to two years. All children in group 1 received a nitrosourea (BCNU or CCNU), plus vincristine in four and procarbazine in three patients. The nine children in group 1 showed clinical and biochemical evidence of gonadal damage with elevated serum FSH concentrations and, in the boys, small testes for their stage of pubertal development. In group 2 (n . 8), each child had completed pubertal development normally, the boys had adult sized testes and the girls regular menses. Gonadotropin values were normal in all eight children. We conclude that nitrosoureas were responsible for the gonadal damage in the children in group 1, with procarbazine also contributing to the damage in the three ...
The effect of the water-chemical regime (WCR) on damage sustained by heating surfaces of steam generators at NPP is analyzed. It is indicated that phosphate treatment with minimal excesses of phosphates in the steamgenerator water is the most optimal method of managing the WCR regime of horizontal steam generators.
Apr 25, 2010... oil per day were leaking from an oil well in the Gulf of Mexico in late April, following an explosion at an offshore drilling rig on April 20, 2010. ...
BackgroundWe have previously reported that low concentrations of cigarette smoke extract induce DNA damage without leading to apoptosis or necrosis in human bronchial epithelial...Full Text Available
BackgroundAs the resident stem cells of skeletal muscle, satellite cells are activated by extracellular cues associated with local damage. Once activated, satellite cells will re-enter...Full Text Available
BackgroundMitochondrial dysfunction, oxidative damage and the accumulation of somatic mutations in mitochondrial DNA (mtDNA) have been associated with certain neurodegenerative disorders....Full Text Available
Chemical reactions in living cells are under strict enzyme control and conform to a tightly regulated metabolic program. However, uncontrolled and potentially deleterious endogenous reactions occur,...Full Text Available
Hepatic damage occurs in males and ovariectomized (OVX), not in proestrus (PE), females following trauma-hemorrhage (T-H). The mechanism responsible for hepatoprotection remains unknown. We hypothesized...Full Text Available
In this paper, we report a method of precise in situ x-ray scattering measurements on protein solutions using small stationary sample cells. Although reduction in the radiation damage...Full Text Available
BackgroundChildhood is a high risk time for ultraviolet induced skin damage as this age group has more time and opportunity to be outdoors in the sun. Children in Africa with the...Full Text Available
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.
Intravascular coagulation, thrombosis, and fibrin deposition often produce tissue damage in allogeneic inflammatory reactions such as allograft rejection. The mechanisms which initiate blood clotting...Full Text Available
Damage to the anterior talofibular ligament (ATFL) and cacaneofibular ligament (CFL) during ankle sprain may be linked to the development of osteoarthritis. Altered tibiotalar kinematics have...Full Text Available
Boron is implanted in crystalline silicon through oxide layers with different thicknesses. The implantation is carried out at various doses and energies of interest in ultra large scale integration (ULSI) application. Rapid thermal annealings (RTA) are used to obtain shallow junctions and electrical activation of the B atoms. However, transient enhanced diffusion induced by implantation damage can be observed. The boron concentration profiles before and after annealing are obtained with secondary ion mass spectrometry (SIMS). It is found that the diffusion transient in the tail region of the boron profile increases with decreasing oxide thickness. Even more, if the implantation damage concerns mostly the oxide, i.e. when the concentration peak is located in this oxide, the oxygen knocked into the silicon substrate could play this way an important role in restricting the boron diffusion, which is good to obtain very shallow junctions. On the ...
Boron is implanted in crystalline silicon through oxide layers with different thicknesses. The implantation is carried out at various doses and energies of interest in ultra large scale integration (ULSI) application. Rapid thermal annealings (RTA) are used to obtain shallow junctions and electrical activation of the B atoms. However, transient enhanced diffusion induced by implantation damage can be observed. The boron concentration profiles before and after annealing are obtained with secondary ion mass spectrometry (SIMS). It is found that the diffusion transient in the tail region of the boron profile increases with decreasing oxide thickness. Even more, if the implantation damage concerns mostly the oxide, i.e. when the concentration peak is located in this oxide, the oxygen knocked into the silicon substrate could play this way an important role in restricting the boron diffusion, which is good to obtain very shallow junctions. On the ...
BackgroundDNA repair is the general term for the collection of critical mechanisms which repair many forms of DNA damage such as methylation or ionizing radiation. DNA repair has...Full Text Available
A series of cyclic strain controlled tests have been carried out at 600/sup 0/C on three high temperature austenitic iron-based alloys, AISI type 316 stainless steel, Alloy 800 H and Sandvik 253 MA. The tests were carried out under constant total strain control using a constant strain rate of 0.005 s/sup -1/. By considering the changes in modulus throughout the life of each specimen it was found that damage evolution could be successfully predicted as a function of plastic strain range despite the fact that each alloy had been chosen because of a different stress response at 600/sup 0/C. Although each alloy accumulated fatigue damage in a similar manner the longer lives of Sandvik 253 MA and Alloy 800 H at a given total strain range were due to a smaller plastic strain component and a reduced stage I crack propagation rate. In the 253 MA alloy, slip was predominantly planar with some cells occasionally forming at high strain ranges. Slip was ...
Accumulation of molecular damage and increased molecular heterogeneity are hallmarks of cellular aging. Mild stress-induced hormesis can be an effective way for reducing the accumulation of molecular...Full Text Available
BackgroundHepatitis C virus is a major cause of chronic liver diseases which can lead to permanent liver damage, hepatocellular carcinoma and death. The presently available treatment...Full Text Available
Acoustic lenses are employed in a variety of applications, from biomedical imaging and surgery to defense systems and damage detection in materials. Focused acoustic signals, for example, enable ultrasonic...Full Text Available
Silent information regulators are potent NAD+-dependent protein deacetylases, which have been shown to regulate gene silencing, muscle differentiation and DNA damage repair. Here,...Full Text Available
Plutonium possesses the most complicated phase diagram in the periodic table, driven by the complexities of overlapping 5f electron orbitals. Despite the importance of the 5f...Full Text Available
Although functional organ stem cells persist in the old, tissue damage invariably overwhelms tissue repair, ultimately causing the demise of an organism. The poor performance of stem cells in an aged...Full Text Available
IntroductionRadiotherapy outcomes might be further improved by a greater understanding of the individual variations in normal tissue reactions that determine tolerance. Most published...Full Text Available
In rats, damage to neuronal populations in some brain regions occurs in response to neonatal alcohol exposure coinciding with the period of rapid brain growth. These alcohol-induced defects...Full Text Available
A summary of research conducted during the first year is presented. The research objectives were sought by conducting two tasks: (1) investigation of probabilistic design techniques for reliability-based design of composite sandwich panels, and (2) examin...
Cracking resistance and metal damage are considered in relation to structural state for steam-pipe fittings during use. An approximate scheme is given for estimating the maximum permissible operating time in the plastic state in relation to the depth of an observed crack-type defect.
During 17 years since the start of operation of the first commercial LWR in Japan, many LWRs have experienced various corrosion damages, but the causes of them were clarified, and the counter-measures were executed effectively in actual plants, as the results, the cause of corrosion damage decreased remarkably, and now, the high rate of operation has become to be maintained. In this paper, the major cases of corrosion damage experienced in LWRs in Japan and foreign countries, the causes of them and the countermeasures, the problems of hereafter and so on are described. The corrosion damage of metallic materials in the environment of LWRs occurs in the parts in contact with high temperature, high pressure water and steam, such as stainless steel piping in the primary cooling system of BWRs, and nickel alloy heating tubes of steam generators, carbon steel feed water piping and zirconium alloy fuel ...
During 17 years since the start of operation of the first commercial LWR in Japan, many LWRs have experienced various corrosion damages, but the causes of them were clarified, and the counter-measures were executed effectively in actual plants, as the results, the cause of corrosion damage decreased remarkably, and now, the high rate of operation has become to be maintained. In this paper, the major cases of corrosion damage experienced in LWRs in Japan and foreign countries, the causes of them and the countermeasures, the problems of hereafter and so on are described. The corrosion damage of metallic materials in the environment of LWRs occurs in the parts in contact with high temperature, high pressure water and steam, such as stainless steel piping in the primary cooling system of BWRs, and nickel alloy heating tubes of steam generators, carbon steel feed water piping and zirconium alloy fuel ...
Stem cell therapies for neurodegenerative disorders require accurate delivery of the transplanted cells to the sites of damage. Numerous studies have established that fluid injections to the hippocampus...Full Text Available
The antitumor agent camptothecin targets DNA topoisomerase I by reversibly stabilizing a covalent enzyme-DNA intermediate. The subsequent collision of DNA replication forks with these drug-enzyme-DNA...Full Text Available
Carbon steel, copper, zinc and aluminium samples were exposed in different sizes with known ambient parameters in Gran Canaria Island and atmospheric corrosion was investigated. Weight-loss measurements used to determine corrosion damage were complemented...
The free radical theory of ageing posits that accrual of oxidative damage underlies the increased cellular, tissue and organ dysfunction and failure associated with advanced age. In support of this...Full Text Available
BackgroundNormal and pathological processes entail the production of oxidative substances that can damage biological molecules and harm physiological functions. Organisms have evolved...Full Text Available
PurposeCataract is the leading cause of blindness and is associated with oxidative damage and protein modification in the lens. In the present study, we have employed proteomic and...Full Text Available
Numbers of non-indigenous species--species introduced from elsewhere - are increasing rapidly worldwide, causing both environmental and economic damage. Rigorous quantitative risk-analysis frameworks,...Full Text Available
Hundreds of thousands of people worldwide live or work in close proximity to steel mills. Integrated steel production generates chemical pollution containing compounds that can induce genetic damage...Full Text Available
The repair process of damaged tissue involves the coordinated activities of several cell types in response to local and systemic signals. Following acute tissue injury, infiltrating inflammatory cells...Full Text Available
SummaryActivating transcription factor 2 (ATF2) is regulated by JNK/p38 in response to stress. Here, we demonstrate that the protein kinase ATM phosphorylates ATF2 on serines...Full Text Available
...visible damage. (k) Corrosion resistance. Each metal part of a...evidence of salt-spray corrosion resistance equal to or greater than...sample of test metal must show corrosion resistance equal to or better than...
Discusses the resolution of the 2. Congress of the Polish Nuclear Society on the energy situation in Poland and recommendations for energy policy. Recommendations for use of nuclear power plants in Poland are made considering environmental pollution from coal combustion (air pollution by sulfur dioxide, nitrogen oxides and carbon dioxide as well as water pollution by salt from mine water discharged to rivers), development of the Polish economy, forecast increase in energy consumption and the role of nuclear energy in other European countries. Research on nuclear power plants, safety and environmental aspects as well as comparative efficiency of coal-fired power plants and nuclear power plants is evaluated.
According to China's 'Medium- and Long-term Nuclear Power Development Program (2005-2020)', nuclear energy development in China will take the technical line of closed nuclear fuel cycle. This paper discusses the significance of closed nuclear fuel cycle, and briefly introduces development trends in the world. This article also discusses the opportunity to construct spent fuel reprocessing plant; equilibrium of plutonium production and consumption; adaptability and economics to use MOX fuel in the thermal neutron reactor. Some suggestions are put forward to the overall development of nuclear energy in China. (authors)
A method of patterning n-type GaAs, InP, InGaAs, and InGaAsP by photoelectrochemical (PEC) etching in conjunction with a submicron focused ion beam (FIB) at low dose is described. The ion beam is used to produce damage in a desired pattern in the material. Subsequent PEC etching of the material reveals the ion induced features in relief. The procedure is highly sensitive, requiring a dose of only 5 x 10/sup 9/ ions/cm/sup 2/ for the differential etch to become apparent. The sensitivity allows rapid pattern generation in our FIB system.
We have performed molecular dynamics simulations of radiation damage in fused silica. In this study, we discuss the role of successive cascade overlap on the saturation and self-healing of oxygen vacancy defects in the amorphous fused silica network. Furthermore, we present findings on the topological changes in fused silica due to repeated energetic recoil atoms. These topological network modifications consistent with experimental Raman spectroscopic observation on neutron and ion irradiated fused silica are indicators of permanent densification that has also been observed experimentally.
In the power station West Block 2 at Voerde (Federal Republic of Germany), cracks in the final stage of the shaft were determined at the ND1 rotor of the 350 MW condensation tube was determined. A purely mechanical preparation of the crack was not possible due to the depth of the crack. A substitute rotor was not available. A repair solution was developed covering a welding of a new shaft section to the existing rotor. The authors of the contribution under consideration report on the damage, cause of the damage, repair solution and the process of repair.
Analytical models for predicting the deformation and failure of composite sandwich panels subjected to blast and projectile impact loading are presented in this paper. The analytical predictions of the transient deformations and damage initiation in the composite sandwich panels were compared with finite element solutions using ABAQUS Explicit. For the blast model, the predicted transient deformation of the sandwich panel was within 7%of FEA results, while the predicted damage initiation using Hashin's composite failure criteria was about 15%higher than FEA results in most cases. For the high velocity impact model, the predicted transient deformations were within 20%of FEA results.
The damage induced by low-temperature proton irradiation in amorphous Pd/sub 80/Si/sub 20/ prepared by ion implantation is studied via electrical resistivity measurements. Our experimental results concerning the initial damage rate and the resistivity saturation are compared to the results obtained for electron and high energy /sup 16/O irradiation of amorphous Pd/sub 80/Si/sub 20/ quenched from the melt. The resistivity curve is analyzed in terms of irradiation-induced point defects.
Life management system is based on the valid nowadays in Estonian power plants regulation documentation. The system allows to estimate stress distribution in components, find computational assessment of cumulated creep damage, determine when and where it is necessary to cut off the particular number of microsamples or take replicas. Finally, the real metal condition may be assessed on the basis of metallographic specimen research and reasonable 3-R decision - run, repair, replacement - made on further component use. (orig.) 6 refs.
Experimental results on study of helium concentration influence on degree of molybdenum radiation hardening for various method of cyclotron doping differing in degree and damage character are presented. It is established that accumulation of helium atoms in molybdenum for simultaneous formation of radiation defects caused by low energetic primary-knocked atoms leads to higher degree of hardening than for high energetic ion irradiation. It is shown that with increase of helium atom concentration the degree of radiation hardening for the same level of damage increases. 4 refs.; 3 figs. (author).
The operation of steam turbines is technically controllable. The manufacturers specify reliable operating ranges as well as demands on the implementation of steam turbines into the power plant process for the respective steam turbines. The VGB guidelines describe the generally valid procedures for the operation of steam turbines in detail. Important insights at some steam turbines are not or only insufficiently converted nevertheless. Damage and extended downtimes at revisions are the result. The author of the contribution under consideration describes some more and more occurring problems. Recommendations and suggestions are given with respect to the avoidance of such findings.
A collection of 14 papers from a June 1981 seminar assess the costs of damage caused by water pollution. The seminar focused on the economic rather than the legal standpoint by evaluating the cost of the clean-up operations themselves and other costs, such as direct or indirect economic losses, and converting into money terms the damage to the environment, the loss of recreational facilities, and biomass losses. The papers are grouped into four sections which look at the scale of risk, the clean-up costs for specific oil spills, other costs inflicted on coastal zones, and legal aspects of compensation. Separate abstracts were prepared for each of the 16 papers selected for the Energy Data Base.
ObjectivesObjectives Not AvailableDescriptionTo determine the effects of water penetration on the burst strength of filament wound composite pipes which have been damaged by impact and then subjected to long term pressurisation with sea water. ~%~ To monitor and characterise the damage and effects of sea water penetration using ultrasonic NDT. To determine the burst strength of bonded composite pipe joints with and without defects and to see whether the defects can be detected using ultrasonic NDT. [continued...
Carbon steel, copper, zinc and aluminium samples were exposed in different sizes with known ambient parameters in Gran Canaria Island and atmospheric corrosion was investigated. Weight-loss measurements used to determine corrosion damage were complemented with metallographic and XP S determination in order to characterize the structure and morphology of surface corrosion products. The ambient aggressiveness could be well evaluated from meteorological and pollution data. All atmospheric corrosion and environmental data were statistically processed for establishing general corrosion damage functions for carbon steel, copper, aluminium and zinc in terms of Gran Canaria extreme meteorological and pollution parameters. (Author)
Effective integration of nonproliferation management into the design process is key to the broad deployment of advanced nuclear energy systems, and is an explicit goal of the Laser Inertial Fusion Energy (LIFE) project at Lawrence Livermore National Laboratory. The nuclear explosives utility of a nuclear material to a state (proliferator) or sub-state (terrorist) is a critical factor to be assessed and is one aspect of material attractiveness. In this work, we approached nuclear explosives utility through the calculation of a ''figure of merit'' (FOM) that has recently been developed to capture the relative viability and difficulty of constructing nuclear explosives starting from various nuclear material forms and compositions. We discuss the integration of the figure of merit into an asse...
This issue is the collection of the papers on progress of researches by common utilization of JAERI nuclear facilities. The 43 of the papers are indexed individually. (J.P.N.)
Nuclear power has been considered for space applications since the 1960s. Between 1955 and 1972 the US built and tested over twenty nuclear reactors/ rocket-engines in the Rover/NERVA programs. However, changes in environmental laws may make the redevelopment of the nuclear rocket more difficult. Recent advances in fuel fabrication and testing options indicate that a nuclear rocket with a fuel form significantly different from NERVA may be needed to ensure public support. The Center for Space Nuclear Research (CSNR) is pursuing development of tungsten based fuels for use in a NTR, for a surface power reactor, and to encapsulate radioisotope power sources. The CSNR Summer Fellows program has investigated the feasibility of several missions enabled by the NTR. The potential mission benefits of a nuclear rocket, historical achievements of the previous programs, and ...
This paper reviews the historical aspects of nuclear physics. The scientific aspects of the early transuranium elements are discussed and arms control measures are reviewed. 11 refs., 14 figs. (LSP)
Development of Scientific Foundations of the Technology of the Metal Matrix Packing of Leaky Unreprocessible Spent Nuclear Fuel of Different Purpose Reactors for a Long-term Environmentally Safe Storage.
This report discusses: shape coexistence in {sup 184}Pt; nuclear structure of {sup 187}Ir; g-factors of excited states; OLNO-2; and refrigerator development.
This report discusses: shape coexistence in "1"8"4Pt; nuclear structure of "1"8"7Ir; g-factors of excited states; OLNO-2; and refrigerator development.
The A-dependence of the nuclear structure functions is described rather well within the framework of the quark-parton-flucton model of nucleus. 16 refs. (author).
The available nuclear structure information for all nuclei with mass number A=242 is presented. Various decay and reaction data are evaluated. Adopted data, levels, spin and parity assignments are given.
U.S. nuclear policy has become the target of increasing criticism during the past decade. Critics often argue that the use of nuclear weapons would be irrational, would destroy humankind, and thus could not serve any rational policy goal. Other critics point to the immortality of the use of nuclear weapons. Both groups condemn U.S. military policy. In Nuclear War, James Child considers and rejects both these lines of criticism. He argues that a policy of deterrence can be both rational and moral; that U.S. nuclear policy is, on balance, based on rational and moral foundations. Child examines near-term consequences of a nuclear war and finds them ghastly but not unthinkable or incomparable to the havoc produced by previous wars. He also analyzes long-term consequences, such as those proposed by the ''nuclear ...
Interactions (FCCI) University of Wisconsin, Madison Thermal Properties of LiCl-KCl Molten Salt for Nuclear Waste Separation University of Wisconsin, Madison Next Generation...
This book discusses the procedures applied for the clinical nuclear medicine laboratory. The procedures are presented as proven guidelines. The chapters are included on quality assurance, radionuclide handling, and radiation safety.
The interpretation of data from the nuclear forensic analysis of illicit nuclear material of unknown origin requires comparative data from samples of known origin. One way to provide such comparative data is to create a system of national nuclear forensics libraries, in which each participating country stores information about nuclear or other radioactive material that either resides in or was manufactured by that country. Such national libraries could provide an authoritative record of the material located in or produced by a particular country, and thus forms an essential prerequisite for a government to investigate illicit uses of nuclear or other radioactive material within its borders. We describe the concept of the national nuclear forensic library, recommendations for content and structure, and suggested querying methods for utilizing the information for ...
We irradiated proton beams on the ears of rabbits and the Harding-Passey mouse melanoma and observed their morphological change. We used 52 MeV proton beams from the INS-FM cyclotron. We adjusted the energy of the proton beams to be at the plateau part of the Bragg curve, at the half-way point of the Bragg peak, and at the Bragg peak. The amount of radiation was 5000rad in each case. The Harding-Passey mouse melanoma was transplanted into the subcutan of a three week old mouse. In this experiment, we used tumors, the diameter of which grew up to 1.5-2cm in 2-3 weeks after the transplantation. Using the jroscope, we observed both lightly and severely damaged cells. Using proton irradiation with the Bragg peak located at depth of 1mm in the rabbit's ears, we studied the change in the tissue. Irradiated epidermis fell off and was eroded because of radiation damage, but the rear surface of the rabbit's ears was only slightly ...
The helicase action of the Escherichia coli UvrAB complex on a covalently closed circular DNA template was monitored using bacterial DNA topoisomerase I, which specifically removes negative supercoils. In the presence of E. coli DNA topoisomerase I and ATP, the UvrAB complex gradually introduced positive supercoils into the input relaxed plasmid DNA template. Positive supercoils were not produced when E. coli DNA topoisomerase I was replaced by eukaryotic DNA topoisomerase I or when both E. coli and eukaryotic DNA topoisomerases I were added simultaneously. These results suggest that like other DNA helix-tracking processes, the ATP-dependent action of the UvrAM complex on duplex DNA simultaneously generates both positive and negative supercoils, which are not constrained by protein binding but are torsionally strained. The supercoiling activity of UvrAB on UV-damaged DNA was also studied using UV-damaged plasmid DNA and a mutant UvrA protein ...
The International Symposium on Nuclear Security took place within a context of international acknowledgement that the threat of nuclear terrorism required dedicated action by the international community, States, industry and others. The Symposium dealt with those issues involved in protecting nuclear and other radioactive material from criminals. It also took place against a backdrop of renewed interest in nuclear technology: increased use of nuclear power, and increased use of radioactive isotopes in medicine and in industry. These are welcome developments, since nuclear energy and technology can indeed contribute to the technological and economic welfare of many countries, without compromising public health or the environment. In this context, security measures should not impede State programmes for peaceful use of nuclear technology. The ...
Nuclear knowledge is the basis for almost all nuclear activities, and education and training are the most fundamental means to transfer knowledge from one generation to the next. Understanding means and trends in knowledge transfer through education and training thus deserves a closer examination. In the past years, a number of trends and questions in nuclear knowledge, education and training have emerged. With declining student enrolment numbers and a general stagnation of the use of nuclear power in some of the IAEA's Member States, the issue of a slow erosion of the knowledge base and the possibility of loosing knowledge has become increasingly important, in particular if seen against the background of a possible renaissance of nuclear power in the future. In other Member States, an expansion of nuclear power is expected, with a corresponding need for human ...
In Daya Bay and Ling'ao Nuclear Power Station, the Microgovernor has the control functions such as synchronization, block loading etc. The control principle of the Microgovernor is right described by sequence diagram for the first time. That the fault occurred in the synchronization process of Daya Bay Nuclear Power Station unit 1 is also analyzed and illustrated. (author)
Stretch-Out and Extended Low Power Operation is two particular operating modes applied for nuclear electricity generation. The relevant safety analysis and the impacts on plant operation are well illustrated, as well as some operation experiences earned in Daya Bay nuclear power station. The safety analysis and plant practice show that Stretch-Out operation and Extended Low Power Operation are operable in Daya Bay nuclear power station
In Hungary, legislation for nuclear power plants was developed at the end of the 1970s, among which is the quality assurance code for nuclear power plants. Hungarian practice is presented, including discussion of the requirements for quality assurance, qualification of the suppliers and inspection practices. The general requirements of quality assurance in the course of construction of a nuclear power plant are presented: quality assurance of technological equipment, fuel, electrical equipment, automatic instrumentations, building structures and technology.
This conference brought together those persons in the nuclear industry who have a vital interest in the training and licensing of nuclear reactor and nuclear fuel processing plant operators, senior operators, and support personnel for the purpose of an exchange of ideas and information related to the various aspects of training, retraining, examination, and licensing. The document contains 64 papers; each paper was abstracted for the data.
Peak at 60 deg in angular proton distribution in inelastic pion-carbon interactions is interpreted as generation of Cherenkov gluon radiation in flucton, passing into the shock wave with successive nucleus decay. Investigation of hadron-nuclear interactions with anomalous peak in angular proton distribution can be used as additional means for study both of flucton and mechanism of hadron-nuclear interactions. 5 refs.
Metastable nuclear isomers are central to the study of nuclear structure and their energy storage capability has suggested a variety of applications. The feasibility of applications depends sensitively on the efficiency of any process that can deplete an isomer upon demand. This work surveys how State-of-the-art in nuclear level and transition data impacts the search for induced energy release from isomers using recent advances in experimental techniques.
As part of a handbook on the efficient use of energy a chapter is included which is intended to give an appreciation of the principles and problems involved in the generation of nuclear power. The subject is discussed under the following headings: introductory nuclear physics; basic reactor physics; thermal reactors; fast reactors; fuel reserves and utilization; environmental considerations; nuclear fusion. (U.K.).
Over the past several years, the Livermore Forensic Science Center has conducted analyses of nuclear-related samples in conjunction with domestic and international criminal investigations. Law enforcement officials have sought conventional and nuclear-forensic analyses of questioned specimens that have typically consisted of miscellaneous metal species or actinide salts. The investigated activities have included nuclear smuggling and the proliferation of alleged fissionable materials, nonradioactive hoaxes such as 'Red Mercury', and the interdiction of illegal laboratories engaged in methamphetamine synthesis. (author)
Evaluated spectroscopic data for all nuclei with mass number A = 216 are presented together with the relevant level schemes from radioactive decay and nuclear reaction studies. The experimental data are evaluated, inconsistencies and discrepancies are noted, and adopted values for level and #gamma#-ray energies, #gamma# intensities, as well as for other nuclear properties are given. The present evaluation supersedes the earlier one on A = 216 by A. Artna-Cohen (1997Ar04), published in Nuclear Data Sheets 80, 157 (1997).
The Comprehensive Nuclear-Test-Ban-Treaty (CTBT), which was opened for signature in 1996, bans all nuclear explosions in all environments. Republic of Korea has been working to monitor compliance with CTBT by deterring and detecting any nuclear explosions conducted anywhere on Earth. For the verification of CTBT, several techniques are implemented. Radionuclide monitoring is of particular importance since it is the only method which can provide absolute assurance that a nuclear detonation has occurred
Features of deep inelastic nuclear reactions proceeding on dense fluctuations of nuclear matter (fluctons) are briefly considered. Fluctons, which can be many-quark bags or drops of quark-gluon plasma, are studied. Their properties are discussed, viz., characteristic parameters of nuclear matter inside a flucton - temperature and density close to the critical values for a phase transition. These values can be reached or exceeded if the flucton-flucton collision events are separated. The separation method is discussed
The possibility of having properly designed multinational fuel cycle agreements which would contribute to public acceptance of nuclear energy are explored. The advantages of existing international cooperation in the field of uranium enrichment and nuclear waste disposal and reprocessing are discussed. The possible forms of multinational co-operation under an international organisation, committed the non-proliferation and operating under international law and covering storage facilities, security of raw materials and the nuclear fuel cycle are summarised in model form. (U.K.).
The in-core reload design procedure, computer codes, design contents and comparison between expected design values and measured values for Daya Bay Nuclear Power Station are presented. The in-core reload design for Daya Bay Nuclear Power Station performed by Nuclear Power Institute of China satisfies the requirements of safety and economy. The expected design values are fit well with measured values
Separate entries were made in the data base for 17 of the 19 papers included. Two papers were previously included in the data base. Workshop reports are included on (1) nuclear level density theories and nuclear model reaction cross-section calculations and (2) extraction of nuclear level density information from experimental data.
Separate entries were made in the data base for 17 of the 19 papers included. Two papers were previously included in the data base. Workshop reports are included on (1) nuclear level density theories and nuclear model reaction cross-section calculations and (2) extraction of nuclear level density information from experimental data. (WHK)
IAEA Plans of activities include, General Conference in September 2001 which reviewed activities relevant to preventing nuclear terrorism and proposed master plan. The Board of Governors approved new Nuclear Security Plan for the next four years. Three activity areas are; - needs assessment, analysis and coordination, prevention and detection and response.
Daya Bay Nuclear Power Station is the largest joint-venture project which is also the largest commercial nuclear power plant currently under construction in China mainland. Organized and executed strictly in accordance with international standards, the Daya Bay project is seen as the first step taken by China in the development programme of large-capacity commercial nuclear power units.
The 1993-1995 period represents a time of significant transition for workers engages in nuclear-related activities. Total nuclear-related employment fell markedly from about 300,000 workers in 1993 to 265, 000 in 1995, a 12% decline. This is the lowest level since the 1970s. In 1995, a third of all nuclear-related employment was in the reactor operation and maintenance segment. 6 figs, 1 table.
Nuclear forensics is a relatively new scientific branch whose aim it is to read out material inherent information from nuclear material. On the basis of material taken in safe-keeping in Germany, the procedure is illustrated and the limits and possibilities of nuclear forensics are shown, in particular the statements that can be made concerning the material, and the relation of the material with respect to a certain location of origin or manufacturing process. (orig.)
The major contents in this study are as follows : - long-term forecast to the year of 2040 is provided for nuclear electricity generating capacity by means of logistic curve fitting method. - the role of nuclear power in a national economy is analyzed in terms of environmental regulation. To do so, energy-economy linked model is developed. By using this model, the benefits from the introduction of nuclear power in Korea are estimated. Study on inter-industry economic activity for nuclear industry is carried out by means of an input-output analysis. Nuclear industry is examined in terms of inducement effect of production, of value-added, and of import. - economic analysis of nuclear power generation is performed especially taking into consideration wide variations of foreign currency exchange rate. The result is expressed in levelized generating costs. (author). ...
The Decree specifies basic quality assurance requirements applicable to machines, their parts and materials, civil engineering structures, means for automated control of technological processes including hardware and software, and electricity supply systems related to nuclear safety of nuclear facilities, and stipulates binding procedures for the implementation of technical and organizational provisions associated with the quality of selected equipment to ensure nuclear safety of nuclear facilities. Safety classes are defined for selected equipment. Requirements laid on safety assurance documentation are specified, and requirements placed on safety assurance programmes, their preparation, finalization and approval are defined. Quality assurance requirements are also specified with respect to the designing, manufacture, construction, operation, repair, modification and decommissioning of ...
The NATO Advanced Research Workshop on Nuclear Submarine Decommissioning and Related Problems was held in Moscow June 19--22, 1995. It was preceded by a visit to the Zvezdotchka Shipyard at Severodvinsk, a repair and maintenance yard for Russian nuclear submarines, for a subgroup of the workshop attendees. Most of the material in this paper is drawn directly form the workshop proceedings. Slightly less than 500 nuclear ships and submarines (the vast majority are submarines) have been constructed by the countries with nuclear navies. This includes approximately 250 by Russia, 195 by the United States, 23 by the United Kingdom, 11 by France and 6 by China. By the year 2000 it is expected that approximately one-half of these nuclear vessels will be removed from service and in various states of decommissioning. A newspaper account in June 1997 indicated that 156 Russian ...
The Nuclear Smuggling International Technical Working Group (ITWG) is an international group of nuclear forensic experts that cooperate to deter the illicit trafficking of nuclear materials. The objective of the ITWG is to provide a common approach and effective technical solutions to governments who request assistance in nuclear forensics. The ITWG was chartered in 1996 and since that time more than 28 nations and organizations have participated in 9 international meetings and 2 analytical round-robin trials. Soon after its founding the ITWG adopted a general framework to guide nuclear forensics investigations that includes recommendations for nuclear crime scene security and analysis, the best application of radioanalytical methods, the conduct of traditional forensic analysis of contaminated materials, and effective data analysis to interpret the history of ...
Fusion energy has been studied in many countries such as U.S., France, Japan, Korea etc. Because it would provide much more energy for a given weight of fuel than any technology currently in use, and the fuel itself (primarily deuterium) exists abundantly in the Earth's ocean. Nuclear fusion reactor uses tritium and deuterium as fuel while nuclear fission reactor uses uranium and plutonium as fuel. Besides, inherent design characteristics and driving condition of nuclear fusion reactor is different from those of nuclear fission reactor. Therefore, we cannot apply the regulation rules of nuclear fission reactor to nuclear fusion reactor without change and thus it is needed to development of the safety regulation concept which reflects the characteristics of nuclear fusion reactor. Safety regulation of nuclear fusion ...
Project management mode plays a key role in project construction, especially in nuclear power field. From the aspects of right, responsibility and benefit, this paper discussed the differences among the common used project management modes. Also the main kinds of the construction management modes used in China's nuclear power plants were summarized. At last, considering the experience of Ningde nuclear power plant, this paper put forward several perspectives about the selection of project management mode in nuclear power plant construction. (authors)
This paper describes the phenomenology of nuclear explosions and technologies for their detection as relevant to On-Site Inspection (OSI) for a comprehensive test-ban (CTB). Our experience with the US nuclear test program which has been primarily carried out at the Nevada Test Site (NTS) and in the Pacific Ocean. The goals of OSI are to resolve ambiguous events, reduce uncertainty, deter attempts at evasion, and provide responsive and technically competent means of confirming the occurrence of a nuclear explosion should deterrence fail. These goals would include finding evidence of an evasive nuclear explosion or evidence that the event was non-nuclear, such as an earthquake or large chemical explosion.
The report presents a summary of the work of the Department of Nuclear Safety Research and Nuclear Facilities in 1995. The department`s research and development activities are organized in three research programmes: Radiation Protection, Reactor Safety, and Radioanalytical Chemistry. The nuclear facilities operated by the department include the Research Reactor DR3, the Isotope Laboratory, the Waste Treatment Plant, and the Educational Reactor DR1. Lists of staff and publications are included together with a summary of the staff`s participation in national and international committees. (au) 5 tabs., 21 ills.
Early in the Cold War, the United States adopted a policy of ''extended nuclear deterrence'' to protect its allies by threatening a nuclear strike against any state that attacks these allies. This threat can (in principle) be used to try to deter an enemy attack using conventional weapons or one using nuclear, chemical, or biological weapons. The credibility of a nuclear threat has long been subject to debate and is dependent on many complex geopolitical factors, not the least of which is the military capabilities of the opposing sides. The ending of the Cold War has led to a significant decrease in the number of strategic nuclear weapons deployed by the United States and Russia. START II, which was recently ratified by the Russian Duma, will (if implemented) reduce the number deployed strategic nuclear weapons on each side to ...
Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe{sup ++}, 360 keV He{sup +}, and 180 keV H{sup +} to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of {approximately} 1 {micro}m. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron ...
This short survey focuses on the main radiation-induced base lesions that have been identified within cellular DNA. For this purpose, sensitive assays that are aimed at measuring a few modifications per 10{sup 7} normal bases were set-up. In that respect high performance liquid chromatography - tandem mass spectrometry (CLHP-MS/MS) was found to be able to single out the formation of 9 oxidized nucleosides and two modified nucleo-bases out of the 70 oxidative base lesions that have been identified in model systems. As a striking result, it was found that in the DNA of {gamma}-irradiated human monocytes, the formamide-pyrimidine derivative of guanine is produced in a higher yield than the ubiquitous 8-oxo-7,8-dihydro-guanine damage, both arising from the same radical precursor. However, relatively high doses of ionizing radiation (> 20 Gy) have to be applied in order to detect an increase in the level of the damage. This is due to the low ...
In attempting to detect and map out underground facilities, whether they be large-scale hardened deeply-buried targets (HDBT's) or small-scale tunnels for clandestine border or perimeter crossing, seismic imaging using reflections from the tunnel interface has been seen as one of the better ways to both detect and delineate tunnels from the surface. The large seismic impedance contrast at the tunnel/rock boundary should provide a strong, distinguishable seismic response, but in practice, such strong indicators are often lacking. One explanation for the lack of a good seismic reflection at such a strong contrast boundary is that the damage caused by the tunneling itself creates a zone of altered seismic properties that significantly changes the nature of this boundary. This report examines existing geomechanical data that define the extent of an excavation damage zone around underground tunnels, and the potential impact on rock ...
We present a proof-of-concept analysis of the measurement of the health damage of ozone (O_3) produced from nitrogen oxides (NO_x=NO+NO_2) emitted by individual large point sources in the eastern United States. We use a regional atmospheric model of the eastern United States, the Comprehensive Air quality Model with Extensions (CAMx), to quantify the variable impact that a fixed quantity of NO_x emitted from individual sources can have on the downwind concentration of surface O_3, depending on temperature and local biogenic hydrocarbon emissions. We also examine the dependence of resulting O_3-related health damages on the size of the exposed population. The investigation is relevant to the increasingly widely used 'cap and trade' approach to NO_x regulation, which presumes that shifts of emission over time and space, holding the total fixed over the course of the summer O_3 season, will have minimal effect on the environmental outcome. By ...
The epileptogenic and neurodegenerative effects of gamma-dendrotoxin, from Dendroaspis angusticeps, a specific blocker of a non-inactivating, voltage-sensitive K+ channel, were studied after focal injection into one dorsal hippocampus in rats pretreated with CGP040116, a N-methyl-D-aspartate (NMDA) receptor antagonist, and in rats bearing a monolateral surgical lesion of the Schaffer collaterals whose terminals originate from CA3 pyramids and release glutamate in the CA1 hippocampal area. Administration of 35 pmol gamma-dendrotoxin elicited in all of the treated animals (n=8) bilateral EEG discharges and damage to the hippocampal formation. Quantitation of the damage revealed significant bilateral neuronal cell loss in the CA1, CA3 and CA4 pyramidal cell layers. The lowest dose (0.35 pmol; n=4) of the toxin used did not affect EEG activity and failed to cause significant hippocampal cell loss whereas the 3.5 pmol (n=6) dose caused EEG seizures ...
A necessary condition for crevice corrosion is that a crevice former create a sufficiently tight, restricted geometry on the metal surface to support the development of critical crevice chemistry. Crevice corrosion is affected by the crevice geometry (tightness) and the properties of the crevice former. The objective of this study is to determine the effect of the crevice former material on the evolution of localized corrosion-damage. A standard crevice corrosion test method is modified by (a) the use of ceramic, metal or polymer materials as the crevice former and (b) the variation of size and shape of the crevice. This study focuses on the post initiation stage of crevice corrosion and addresses factors that may limit the initiation of localized corrosion and also slow or stop the continued propagation of corrosion. Controlled crevice corrosion tests are performed under aggressive, accelerated conditions on Ni-Cr-Mo alloy C-22 and other alloys for comparison. ...
This paper assesses the effects of including carbon dioxide capture and storage (CCS) damage costs in a long-term energy scenario analysis for Europe. An external cost sensitivity analysis is performed with a bottom-up energy technology model that accounts not only for CCS technologies but also for their external costs. Our main conclusion is that in a business-as-usual scenario (i.e. without climate change intervention or externality internalisation), CCS technologies are likely to be deployed at least to some extent, mainly in the power generation sector, given the economic benefits of opportunities such as enhanced coal bed methane, oil and gas recovery. Under a strict climate (CO{sub 2} emissions) constraint, CCS technologies are deployed massively. With the simultaneous introduction of both CO{sub 2} and CCS taxation in the power sector, designed to internalise the external atmospheric and geological effects of CO{sub 2} emissions and storage, respectively, we ...
Geological carbon dioxide capture and storage (CCS) is currently seriously considered for addressing, in the near term, the problem of climate change. CCS technology is available today and is expected to become an increasingly affordable CO2 abatement alternative. Whereas the rapidly growing scientific literature on CCS as well as experimental and commercial practice demonstrate the technological and economic feasibility of implementing this clean fossil fuel option on a large scale, relatively little attention has been paid so far to the risks and environmental externalities of geological storage of CO2. This paper assesses the effects of including CCS damage costs in a long-term energy scenario analysis for Europe. An external cost sensitivity analysis is performed with a bottom-up energy technology model that accounts not only for CCS technologies but also for their external costs. Our main conclusion is that in a business-as-usual scenario (i.e. without climate ...
For satisfaction of international growing demand for electrical energy it is impossible to ignore contribution of nuclear power. With an expected lifespan for nuclear plants estimated to 50-60 years of operation (years for decommissioning added), there is a need for a steady multi-generational stream of competent staff to ensure safe operations of nuclear plants. It is incumbent to governments to invest in education, research, and training for the three to five generations of people who will construct, operate and eventually decommission nuclear plants over the duration of their life cycle. To develop sustained nuclear programs it is necessary to carry out a lot of major problems, but three of them look like as most important: 1. Training a qualified and competent personal to ensure all nuclear activities; 2. Multilateral approach for ...
In Romania, the nuclear power is an element of sustainable development, being competitive, efficient and viable in the market economy. Fuel supply is ensured as nuclear fuel is manufactured in the country out of local uranium resources available in Romania. As for the environmental protection, it is known that, unlike the thermal power plants, the nuclear power plants do not release sulfur and nitrogen oxides, carbon dioxide and do not generate slag and ashes. The operation of nuclear power units does not release pollutants and, accordingly, these stations can contribute to the limitation and the abatement of environmental pollution. After seven years of Cernavoda NPP Unit 1 operation, a facility for storing low and medium level nuclear fuel wastes was built at the plant site as well as an intermediate dry storage for spent nuclear fuel whose first modules were ...
The purpose of this research is to clarify how psychological factor's impact on public acceptance of nuclear energy varies with people's degree of knowledge. For this purpose, we carried out questionnaire survey about nuclear energy at Suginami ward, Tokyo. After collecting data, we applied factor analysis to the data, and found 4 factors: Trust in the Authorities, Superiority of Nuclear Power Generation, Benefit for Nuclear Power Plants' Siting Areas, and Risk Perception about Nuclear Technology. In addition, using multiple regression analysis, we evaluated the impact of the 4 factors on 2 issues: the decision for or against nuclear policy and the reaction to nuclear power plant siting. Consequently, we found the change of impact of all 4 factors on the 2 issues. Especially, the impact of the 4 factors to the ...
Standardization enhances: international cooperation; development of new nuclear techniques and technologies; characterization and checking procedures of equipment; sharing a common terminology. A historical sketch is given focussing: inception of standardization in electro-techniques at international scale; organization of the International Electrotechnical Commission, IEC; - current aspects of nuclear equipment standardization; activity of seven working groups devoted to nuclear reactor equipment; activity of seven groups working on radioprotection equipment; activity of four groups working on nuclear equipment. ISO organization and present issues concerning the nuclear technology development in Romania. It is presented the activity in the frame of CENELEC, CLC/TC45, for endorsing the IEC/TC45B standards. In 2007 a CENELEC/ BTT 127-1 working commission was formed to enhance ...
On 24th of July 2007 Westinghouse Electric Co. signed landmark contracts with China's State Nuclear Power Technology Corporation (SNPTC), to provide four AP1000 nuclear power plants in China. The AP1000 is a two-loop 1117 MWe Pressurized Water Reactor (PWR). It is based on proven technology, but with an emphasis on safety features that rely on natural driving forces, such as pressurized gas, gravity flow, natural circulation flow and convection. Ansaldo Nucleare has provided a significant support to the passive plant technology development and, starting from 2000, is cooperating with Westinghouse to development of the AP1000 Plant. In the frame of the AP1000 Chinese agreement, Ansaldo Nucleare, in Joint Venture with Mangiarotti Nuclear, has signed a contract with Westinghouse for the design and the supply of innovative components to be installed in the first AP1000 unit to be ...