Energy Technology Data Exchange (ETDEWEB)

The general strategy for improving the safety of nuclear power plant and its economics is to accomplish power uprates while securing sufficient thermalhydraulic margin. In order to succeed this strategy, there have been a lot of efforts in increasing the margin through the enhancement of heat transfer capability in coolants. However, despite their efforts, only about 10 {approx} 15 % increase of the thermal margin is possible by using the best art known well up to now with installation of mechanical engineering devices such as mixing vane or button to generating the swirl flow and turbulent mixing. The limit of the capability of the best technique has made a lot of engineers to be frustrated to do the power uprates. Nevertheless, fortunately a new innovative idea is being proposed in heat transfer community as an engineering colloidal fluid to basically change the original properties of the coolant. The ...

Energy Technology Data Exchange (ETDEWEB)

This report, the fifth in a series of annual reports, was prepared in response to congressional inquiries concerning how nuclear regulatory research is used. It summarizes the accomplishments of the Office of Nuclear Regulatory Research during FY 1989. The goal of this office is to ensure that safety-related research provides the technical bases for rulemaking and for related decisions in support of NRC licensing and inspection activities. This research is necessary to make certain that the regulations that are imposed on licensees provide an adequate margin of safety so as to protect the health and safety of the public. This report describes both the direct contributions to scientific and technical knowledge with regard to nuclear safety and their regulatory applications.

Energy Technology Data Exchange (ETDEWEB)

This report, the seventh in a series of annual reports, was prepared in response to congressional inquiries concerning how nuclear regulatory research is used. It summarizes the accomplishments of the Office of Nuclear Regulatory Research during FY 1991. The goal of this office is to ensure that safety-related research provides the technical bases for rulemaking and for related decisions in support of NRC licensing and inspection activities. This research is necessary to make certain that the regulations that are imposed on licensees provide an adequate margin of safety so as to protect the health and safety of the public. This report describes both the direct contributions to scientific and technical knowledge with regard to nuclear safety and their regulatory applications.

Energy Technology Data Exchange (ETDEWEB)

This report, the fourth in a series of annual reports, was prepared in response to Congressional inquiries concerning how nuclear regulatory research is used. It summarizes the accomplishments of the Office of Nuclear Regulatory Research during 1988. The goal of this office is to ensure that safety-related research provides the technical bases for rulemaking and for related decisions in support of NRC licensing and inspection activities. This research is necessary to make certain that the regulations that are imposed on licensees provide an adequate margin of safety so as to protect the health and safety of the public. This report describes both the direct contributions to scientific and technical knowledge with regard to nuclear safety and their regulatory applications.

UK PubMed Central (United Kingdom)

Purpose.The hypothesis that drivers with homonymous hemianopia (HH) would take a lane position that increased the safety margin on their blind side was tested with a driving simulator.Methods.Twelve...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In CANDU reactors, the Regional Overpower Protection Trip (ROPT) system protects the reactor against overpowers in the reactor fuel, whether due to localized peaking within the core or a general increase in core power levels. Due to Primary Heat-Transport System (PHTS) aging the ROP trip setpoint is decreasing over time. Reductions in ROP trip setpoints are required to maintain the required trip-probability and ROP trip effectiveness, and results in a decrease of the ROP margin-to-trip during normal operation. In addition, full power operation can be threatened. In this point, to recover ROPT margin, channel power needs to be redistributed. ROPT setpoint is very conservative in normal operation because distortion of regional overpower is over 1.2 times as nominal power in slow loss of regulation (SLOR). Channel power ratio (CPR) is enough low except the limiting channel of which worst case of design ...

International Nuclear Information System (INIS)

The super simulator 'SAMPSON' has been developed to show that there exist certain safety margins for light water reactors under hypothetical severe accidents and to investigate realistic measures of accident management by simulating accidents with a parallel computer. Heat-up of fuel rods and release of fission products from fuels are important factors to evaluate source terms. Models for fuel rod heat-up, hydrogen production due to cladding oxidation and cladding deformation and failure in the core region have been developed in the fuel rod heat-up analysis module. Fuel temperatures were calculated by solving the heat conduction equation. The calculated results for fuel temperature and hydrogen production were compared with CORA-13 experiment results. The comparisons showed prediction capability for the heat-up of fuel rods. The fission product release analysis module incorporates with models for fission product transport ...

Energy Technology Data Exchange (ETDEWEB)

Safe and economical operations with fissile materials require knowledge of the subcriticality of configurations that arise in material processing, storage, and transportation. Data from critical experiments have been a principal source of information with which to establish safety margins. However, the lower cost and the expediency of performing confirmatory subcritical measurements on the process floor or in the storage vault resulted in much of the early criticality safety guidance being based on subcritical in situ experiments.

International Nuclear Information System (INIS)

One of the characteristic safety features of a pool type research reactor is a safety flapper valve. The valve enables natural convection cooling mechanism in one of the following events. (a) Opening flapper valve promote decay heat removal following reactor's shutdown. (b) Also the valve is gravity driven. There is a possibility that the valve fails to open when it is required to do so. In the present paper the cooling characteristics of the core are analyzed for this event. A steady state study was performed for 5 MW power and 18 FE following a reactor shutdown. It is shown that enough margin exists to assure adequate reactor core cooling should the safety flapper valve fails to open. (authors)

International Nuclear Information System (INIS)

The possibility of developing reactor designs with inherent safety characteristics sufficient to provide walk away safety is receiving additional emphasis in the LMR program. A key element in this effort is the recognition that LMR's possess safety characteristics above and beyond those employed in past safety review processes. Some of these additional safety characteristics are due to reactivity feedback effects caused by small structural movements during hypothetical severe design transients. The effects of these characteristics upon the behavior of the FFTF under such transients has been assessed and is discussed in this paper. The paper also presents a preliminary test matrix which might allow experimental verification of the structural reactivity feedback effects. Such experimental verification should be very useful to innovative designers seeking to ...

Energy Technology Data Exchange (ETDEWEB)

JAERI has been performing transient core thermal-hydraulic test program. In the program, authors performed BWR/ABWR DBE simulation tests with a test facility, which can simulate BWR/ABWR transients. The test facility has a 4 x 4 bundle core simulator with 15-rod heaters and one non-heated rod. Through the tests, authors quantified the thermal safety margin for core cooling. In order to quantify the thermal safety margin, authors collected experimental data on post-CHF. The data are essential for the evaluation of clad temperature transient when core heat-up occurs during DBEs. In comparison with previous post-CHF tests, present experiments were performed in much wider experimental condition, covering high clad temperature, low to high pressure and low to high mass flux. Further, data at wider elevation (lower to higher elevation of core) were obtained in the present experiments, which make possible to ...

International Nuclear Information System (INIS)

The safety approach of the Advanced Liquid Metal Reactor program, sponsored by the U.S. Department of Energy, relies upon passive reactor responses to off-normal conditions to limit power and temperature excursions to levels that allow large safety margins. Gas expansion modules (GEM) have been included in the design to provide negative reactivity to enhance these margins in the extremely unlikely event that pumping power is lost and the highly reliable scram system fails to operate. The feasibility and beneficial features of these devices were first demonstrated in the core of the Fast Flux Test Facility (FFTF) in 1986. Pre-application safety evaluations by the U.S. Nuclear Regulatory Commission have identified areas that must be addressed if these devices are to be relied on. One of these areas is the response of the reactor when it is critical and the pumps are turned on, ...

International Nuclear Information System (INIS)

During the operation of the Fast Flux Test Facility (FFTF), radioactive gases, primarily xenon and krypton, will be produced which will require processing and storing. Two systems have been installed in the FFTF for handling these gases: (1) one to handle, primarily, the reactor cover gas system, and (2) a second to handle the cells and cover gas systems, other than the reactor, whose atmosphere may become contaminated. The system that processes the reactor cover gas, which is argon, is called the Radioactive Argon Processing System (RAPS). The effluent argon from RAPS will normally be sufficiently decontaminated to allow its reuse as the reactor cover gas. If the radioactive level in the RAPS becomes too high, the exhaust stream will be diverted to the Cell Atmosphere Processing System (CAPS), a system which can function as a backup to RAPS. The design and operation of the RAPS and CAPS systems are described and certain safety aspects of the systems are discussed. ...

International Nuclear Information System (INIS)

There are a total of nine operational nuclear plants in Spain totalling 7.350 MWe. These units produced 54.265 x 106 KWh in 1990, 36% of the total generation in Spain. Seven of these plants are of the PWR type. The first plant in operation was Jose Cabrera (ZORITA) in 1968, one loop Westinghouse plant with a model 24 Steam Generator. Due to the design margin and careful operation of the Steam Generator of this plant its performance have been very good, with only 5% tubes plugged after 23 years of operation. This is one of the few units in the world that remains in phosphate chemistry. During the period 1981-1985 a total of four units, two in Almaraz and two in Asco entered in operation. These three loop s Westinghouse units use model D-3 preheater Steam Generators. The poor design and manufacture of the Steam Generators of these units have caused a large number of problems: mechanical (Preheater and AVB's vibration), denting, and primary and ...

Energy Technology Data Exchange (ETDEWEB)

In this work, a model for determining the optimal inspection and replacement periods of the safety system in Wolsung Nuclear Power Plant Unit 1 is developed, which is to minimize economic loss caused by inadvertent trip and the system failure. This model uses cost benefit analysis method and the part for optimal inspection period considers the human error. The model is based on three factors as follows: (i) The cumulative failure distribution function of the safety system, (ii) The probability that the safety system does not operate due to failure of the system or human error when the safety system is needed at an emergency condition and (iii) The average probability that the reactor is tripped due to the failure of system components or human error. The model then is applied to evaluate the safety system in Wolsung Nuclear Power Plant Unit ...

UK PubMed Central (United Kingdom)

Natural resources in general and plant materials in particular are receiving more attention due to their safety as pharmaceutical excipients. Present work assessed the potential of a natural polysaccharide,...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The recent announcement that the public inquiry into the CEGB's plans to build a PWR at Sizewell will begin in January 1983 and the statement which followed from the task force that was set up in July 1981 to consider the future of the PWR programme in the UK, are considered. The relevant time scales, costs and safety, in particular the cost incurred due to the added safety features for the British PWR, are discussed. The effect of political aspects on the future of the PWR in Britain is considered.

Energy Technology Data Exchange (ETDEWEB)

The Soviet Union does not currently have an overall radioactive waste management program or national laws that define objectives, procedures, and standards, although such a law is being developed, according to the Soviets. Occupational health and safety does not appear to receive major attention as it does in Western nations. In addition, construction practices that would be considered marginal in Western facilities show up in Soviet nuclear power and waste management operations. The issues involved with radioactive waste management and environmental restoration are being investigated at several large Soviet institutes; however, there is little apparent interdisciplinary integration between them, or interaction with the USSR Academy of Sciences. It is expected that a consensus on technical solutions will be achieved, but it may be slow in coming, especially for final disposal of high-level radioactive wastes and environmental restoration of ...

International Nuclear Information System (INIS)

This paper describes the CANDU fuel development activities in Canada during 1997 through 1998. The activities include those of the Fuel Technology Program sponsored by the CANDU Owners Group. The goal of the Fuel Technology Program is to maintain and improve the reliability, economics and safety of CANDU fuel in operating reactors. These activities, therefore, concentrate on the present designs of 28-element and 37-element fuel bundles. The Canadian fuel development activities also include those of the Advanced Fuel and Fuel Cycle Technology Program at AECL. These activities concentrate on the development of advanced fuel designs and advanced fuel cycles, which among other advantages, can reduce the capital and fuelling costs, maintain operating margins in aging reactors, improve natural-uranium utilization, and reduce the amount of spent fuel. (author)

Energy Technology Data Exchange (ETDEWEB)

The {sup 252}Cf-source-driven frequency analysis method can be used for measuring the subcritical neutron multiplication factor of arrays of LWR fuel and as little as a single PWR fuel assembly. These measurements can be used to verify the criticality safety margins of spent LWR fuel configurations and thus could be a means of obtaining the information to justify burnup credit for spent LWR transportation/storage casks. In addition, the data can be used to validate calculational methods for criticality safety. These measurements provide parameters that have a higher sensitivity to changes in fissile mass than neutron multiplication factor and thus serve as a better test of calculational methods. The analysis have also shown that measurement of the cross power spectral density (CPSD) between detectors on one side of a single fuel assembly and an internal or external {sup 252}Cf source driving the fission chain multiplication ...

International Nuclear Information System (INIS)

BWRs are so designed that the exhaust steam from main steam safety relief valves is led to pressure suppression pools, and the steam is condensed in pool water, but at this time, dynamic load seems to arise in the pool water. In Tokai No. 2 Power Station, a Mark-2 containment vessel was adopted to improve the reliability as much as possible and to obtain the design with margin. In this report, the result of actual machine test in Tokai No. 2 Power Station and the method of reducing the load are described. When a relief valve works, the discharge of water in exhaust pipes into a suppression pool, the exhaust of air in exhaust pipes and repeated expansion and contraction of bubbles in pool water, and the exhaust of steam and condensation occur. As for the construction of the suppression pool in Tokai No. 2 Power Station, cross-shaped quencher and the structure with jet deflector were installed. The test plan and the test result with an actual ...

Energy Technology Data Exchange (ETDEWEB)

The stability of a forced-flow cooled superconducting coil is investigated by use of the numerical simulation. The numerical code to integrate the simultaneous partial differential system composed of the 1 D hydrodynamic equations and the 1 D thermal conduction equation has been developed and stability margins are evaluated as functions of coolant mass flow rate, operation current and imposed magnetic field. The results of computations show that the stability margin is multi-valued with respect to these operation parameters, as expected from the experimental results. It is also shown that the appearance of the first unstable regime is closely related to the existance of the stagnant region located at the upstream side of the heated zone and that the second stable regime appears because the heat transfer is appreciably enhanced by the induced backflow due to the thermal expansion of coolant. 13 refs., 13 figs., 1 tab.

Energy Technology Data Exchange (ETDEWEB)

A risk-based sensor placement methodology is proposed to solve the problem of optimal location of sensors or detectors to protect population against the exposure to and effects of known and/or postulated chemical, biological, and/or radiological threats. Risk is calculated as a quantitative value representing population at risk from exposure against standard exposure levels. Historical meteorological data are used to characterize weather conditions as the frequency of wind speed and direction pairs. The meteorological data drive atmospheric transport and dispersion modeling of the threats, the results of which are used to calculate risk values. Sensor locations are determined via an iterative dynamic programming algorithm whereby threats captured or detected by sensors placed in prior stages are removed from consideration in subsequent stages. In addition to the risk-based placement algorithm, the proposed methodology provides a quantification of the marginal ...

International Nuclear Information System (INIS)

The object of this paper is to identify the key elements that impact a radiation dose at EAB (Exclusion Area Boundary). This study is based on the AST (Alternative Source Terms) as defined in Regulatory Guide 1.183. The LOCA (Loss of Coolant Accident) and the LRA (Locked Rotor Accident) are selected as limiting cases. A sensitivity analysis of accidental behavior with respect to various parameters during LOCA and LRA at Kori Unit 1 is also undertaken for the following objectives: to determine the limiting parameters, to find the impact trend of the radiation dose, and to find the safety margin between AST and TID (Technical Information Document) methodologies. This work confirms that key parameters are particulate removal rate, decontamination factor, iodine chemical form, gap fraction, partitioning factor, and the impact of isotopes group. Comparing TID with AST, the radiation dose of TID is about 80% greater than that of AST under a LOCA, and ...

Science.gov (United States)

This report summarizes the results of an expert-opinion elicitation activity designed to qualitatively assess the status and capabilities of currently available computer codes and models for accident analysis and reactor safety calculations of advanced sodium fast reactors, and identify important gaps. The twelve-member panel consisted of representatives from five U.S. National Laboratories (SNL, ANL, INL, ORNL, and BNL), the University of Wisconsin, the KAERI, the JAEA, and the CEA. The major portion of this elicitation activity occurred during a two-day meeting held on Aug. 10-11, 2010 at Argonne National Laboratory. There were two primary objectives of this work: (1) Identify computer codes currently available for SFR accident analysis and reactor safety calculations; and (2) Assess the status and capability of current US computer codes to adequately model the required accident scenarios and associated phenomena, and identify important gaps. ...

International Nuclear Information System (INIS)

There are good prospects for silicon carbide anti-corrosion coatings on fuel elements to be realised, which opens up the chance to reduce the safety engineering requirements to the suitable design and safe performance of the ceramic fuel element. Another possibility offered is combined-cycle operation with high efficiencies, and thus good economic prospects, as with this design concept combining gas and steam turbines, air ingress due to turbine malfunction is an incident that can be managed by the system. This development will allow economically efficient operation also of nuclear power reactors with relatively small output, and hence contribute to reducing CO_2 emissions. (orig./DG).

International Nuclear Information System (INIS)

The ROP margin in a CANDU reactor is decreasing over time due to the Primary Heat-Transport System (PHTS) aging effect. Adjustment of the ROP trip setpoint is required to maintain a high trip-probability and ROP trip effectiveness. Especially, for Wolsong-1, which is scheduled to change the old pressure tubes in 2009, the trend of ROPT after the retubing should be reevaluated. Before setting a ROPT, the main thermal characteristics including Critical Channel Power (CCP) should be calculated by the NUCIRC code. In this paper, the thermalhydraulic evaluation for Wolsung-1 was conducted with the updated Wolsung-1 PHTS data. Specifically, for the case of 0 EFPY (Effective Full Power Year) and 11 EFPY after the retubing, the distribution of the channel flow rate, channel exit quality, critical channel power, and critical power ratio (CPR) of the Wolsong-1 aged plant are calculated

British Library Electronic Table of Contents (United Kingdom)

This study looks at the land use impact of the biofuels expansion on both the intensive and extensive margin, and its environmental consequences. We link economic, geographical and environmental models by using spatially explicit common units of analysis and use remote sensing crop cover maps and digitized soils data as inputs. Land use changes are predicted via economic analysis of crop rotation choice and tillage under alternative crop prices, and the Environmental Policy Integrated Climate (EPIC) model is used to predict corresponding environmental impacts. The study focuses on Iowa, which is the leading biofuels hotspot in the U.S. due to intensive corn production and the high concentration of ethanol plants that comprise 28% of total U.S. production. We consider the impact of the biof...

Energy Technology Data Exchange (ETDEWEB)

An assessment of the cooling requirements for fusion reactor components, such as the first wall and limiter/divertor, was carried out using pressurized water as the coolant. In order to establish the coolant operating conditions, a survey of the literature on departure from nucleate boiling, critical heat flux, asymmetrical heating and heat transfer augmentation techniques was carried out. The experimental data and the empirical correlations indicate that thermal protection for the fusion reactor components based on current design concepts can be provided with an adequate margin of safety without resorting to either high coolant velocities, excessive coolant pressures, or heat transfer augmentation techniques. If, however, the future designs require heat transfer enhancement techniques, experimental verification would be necessary since no data on heat transfer augmentation techniques exist for complex geometries, especially under ...

Energy Technology Data Exchange (ETDEWEB)

An assessment of the cooling requirements for fusion reactor components, such as the first wall and limiter/divertor, was carried out using pressurized water as the coolant. In order to establish the coolant operating conditions, a survey of the literature on departure from nucleate boiling, critical heat flux, asymmetrical heating and heat transfer augmentation techniques was carried out. The experimental data and the empirical correlations indicate that thermal protection for the fusion reactor components based on conventional design concepts can be provided with an adequate margin of safety without resorting to either high coolant velocities, excessive coolant pressures, or heat transfer augmentation techniques. If, however, the future designs require unconventional shapes or heat transfer enhancement techniques, experimental verification would be necessary since no data on heat transfer augmentation techniques exist for complex geometries, ...

International Nuclear Information System (INIS)

The seismic analysis of nuclear island of Daya Bay Nuclear Power Plant (NPP) was just in accordance with the approaches in RCC-G standard for the model M310 in France, in which the simplified impedance matrix method was employed for the consideration of soil's function. In this paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the function of soil. In addition, multi-group of input time histories was used in the seismic response analysis in the existing design and their average of responses for each group was taken as the design basis. The same multi-group of input time histories was used in the seismic response analysis in this study, but the average and enveloped value of responses for each case are calculated respectively to account for the uncertainty of input motions. Focused on the above two issues, the seismic responses of the reactor building are calculated and the floor response spectra (FRS), a very important ...

International Nuclear Information System (INIS)

The core of Prismatic Modular Reactor (PMR) consists of assemblies of hexagonal graphite fuel and reflector elements. The core bypass flow of Very High Temperature Reactor (VHTR) is defined as the core flow that does not pass through the coolant channels but passes through the bypass gap between fuel elements. The increase in bypass flow makes the decrease in effective coolant flow. Since the core bypass flow has a negative impact on safety and efficiency of VHTR, core bypass phenomena have to be investigated to improve the core thermal margin of VHTR. For this purpose, the international project, I-NERI project, has been carried out since 2008. I-NERI project is collaborative project that KAERI and SNU of Korea side and INL, ANL and TAMU of U.S side are involved. In order to evaluate the core bypass flow, the multicolumn and multi-layer experimental facility is designed by SNU. In this experiment, the effect of cross-flow and local variation of ...

International Nuclear Information System (INIS)

Debris coolability in the lower plenum of the reactor pressure vessel is an important factor for evaluation of debris in-vessel retention. The debris coolability analysis module is developed for the accurate prediction of the safety margin of the present reactor vessels in a severe accident. The module calculates debris spreading and cooling through melting and solidification in combination with a temperature distribution and failure evaluation of the vessel wall. Debris spreading is solved by the explicit method on a quasi-three-dimensional scheme and debris coolability is solved on the basis of natural convection analysis. The calculation for spreading is compared with a water spreading experiment on the floor and the calculation for coolability is compared with a n-octadecane melting experiment in a rectangular vessel. The comparisons show capabilities for predictions of spearhead transportation in the debris spreading process and of melting ...

Energy Technology Data Exchange (ETDEWEB)

Electrical power is generated by steam turbines (steam being produced by coal, oil, gas or nuclear reactors), hydro units, gas turbines, internal combustion engines, jet engines, and pumped storage plants. Nuclear Power Plants generate only 15% of the total electrical power in the US. Nuclear Power Plants being cheaper to run are generally base loaded. The pumped-storage and gas turbine plants have ideal characteristics for peaking duty. In the pumping mode, pumped storage plants are used to provide additional system load and in the generating mode, they supply reactive power during peak load demands. Gas turbine plants have higher running costs, but are used as peaking units with a fast start capability. Fossil power plants need a minimum of 1 hour to stabilize expansion in the boiler and turbine generator. Due to a more competitive power supply market due to deregulation, most of the utilizes plan generation only for the next three years. ...

Energy Technology Data Exchange (ETDEWEB)

Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code ...

International Nuclear Information System (INIS)

The study of the melting of combustible rods is of great importance for the safety analysis of nuclear reactors. Due to the special characteristics of the problem, a sharp interface between the solid and liquid region does not exist, but appears a 'mushy' region in which the material is partially melted. The Finite Element Method is employed here, together with a regularized enthalpy formulation. Finally, the results obtained are presented and discussed. (Author).

International Nuclear Information System (INIS)

The Chuetsu-oki Earthquake strongly shook the Kashiwazaki-Kariwa Nuclear Power Station with the ground motions exceeding the design values. The incidents include a fire breakout of the Unit 3 transformer, a release of spilled water containing small amount of radioactive materials to the non-radiation control area and subsequently to the environment at Unit 6, and a release of radioactive material from the main turbine condenser through the main stack of Unit 7 due to the delay stooping the turbine gland steam ventilator by the operator in manually, while every unit in operation was safety shutdown in the automatic mode ensuring the three fundamental safety functions of (a) reactivity control, (b) removal of heat from the core and (c) confinement of radioactive materials. Following integrity evaluation and performance testing of the overall plant, seismic safety of buildings, structures, equipment and ...

Energy Technology Data Exchange (ETDEWEB)

Six safety initiatives have been identified for accelerating the resolution of waste tank safety issues and closure of unreviewed safety questions. Safety Initiative 5 is to reduce safety and environmental risk from tank leaks. Item d of Safety Initiative 5 is to complete corrosion studies of single-shell tanks to determine failure mechanisms and corrosion control options to minimize further degradation by June 1994. This report has been prepared to fulfill Safety Initiative 5, Item d. The corrosion mechanisms that apply to Hanford Site single-shell tanks are stress corrosion cracking, pitting/crevice corrosion, uniform corrosion, hydrogen embrittlement, and microbiologically influenced corrosion. The corrosion data relevant to the single-shell tanks dates back three decades, when results were obtained from in-situ corrosion coupons in a few ...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Although the esthetic outcome of a collarless metal ceramic restoration is superior to that of a restoration with a metal margin, its mechanical strength has not been evaluated. Purpose The purpose of this study was to evaluate and compare the fracture resistance of metal ceramic restorations with metal margins to that of metal ceramic restorations with circumferential porcelain margins, after exposure to masticatory simulation. Material and methods Twenty-four metal ceramic restorations were fabricated and paired with 24 cobalt-chrome tooth analogs. Twelve of the specimens had metal margins, while the remainder had circumferential porcelain margins. The restorations were cemented on the metal tooth analogs with a resin-modified glass ionomer luting agent (FujiCEM). Al...

Science.gov (United States)

Within the Williston basin, thickness variations of the Prairie Formation are common and are interpreted to originate by two processes: differential accumulation of salt during deposition and differential removal of salt by dissolution. Unambiguous evidence for each process is rare because the Prairie/Winnipegosis interval is seldom cored within the US portion of the basin. Therefore, indirect methods, using well logs, provide the principal method for identifying characteristics of the two processes. The results of this study indicate that the two processes can be distinguished using correlations within the Prairie Formation. Several regionally correlative brining-upward and probably shoaling-upward sequences occur within the Prairie Formation. Near the basin center, the lowermost sequence is transitional with the underlying Winnipegosis Formation. This transition is characterized by thinly laminated basal carbonates that become increasingly interbedded with anhydrites of the ...

Energy Technology Data Exchange (ETDEWEB)

Studies technological safety of installing a water spray pressure vessel between electrostatic dedusters and coal sludge ducts. These sprays are in use elsewhere for steam generator ash removal. Dust ignition and explosion tests were carried out to examine flame and pressure wave propagation through the vessel into ducts. Water jet diameter, amount of water sprayed and coal dust removed were varied. Pressure waves exceeded 250 Pa. Test results show the vessel to be suitable for installation in briquetting plants due to its flame and explosion barrier effect and extermination of smoldering dust fires. The only disadvantage of the vessel is seen as its water and electric power consumption; about 8/sup 3//h of water and 1.5 kW/h of power per vessel serving dedusters of a 2,200 m/sup 2/ rotary brown coal dryer.

International Nuclear Information System (INIS)

Perspectives from industry, academe, and the NRC are brought together in this report and used to develop a logical framework that links management and organization factors and safety in nuclear power plant performance. The framework focuses on intermediate outcomes which can be predicted by organizational and management factors, and which are subsequently linked to safety. The intermediate outcomes are efficiency, compliance, quality, and innovation. The organization and management factors can be classified in terms of environment, context, organizational governance, organizational design, and emergent processes. Initial empirical analyses were conducted on a limited set of hypotheses derived from the framework. One set of hypotheses concerned the relationships between one of the intermediate outcome variables, efficiency, as measured by critical hours and outage rate, and safety, as measured by 5 NRC indicators. Results of ...

UK PubMed Central (United Kingdom)

Chronic autoimmune or pathogen-induced immune reactions resulting in lymphoid neogenesis are associated with development of malignant lymphomas, mostly extranodal marginal zone B-cell lymphomas (MZBCLs)....Full Text Available

Science.gov (United States)

... geographically flexible rapid- deployment forecasting system that directly leverages the CORIE modeling and information management capabilities. ...

Energy Technology Data Exchange (ETDEWEB)

In designing power system stabilizer (PSS), a major difficulty is to successfully treat the system`s uncertainties. These uncertainties arise because of changes in operating conditions, approximations in modeling, parameter variations caused by faults, etc. It is known that in the presence of uncertainties, conventional methodologies such as linear optimal technique, adaptive controls, etc., may fail to guarantee the stability of the system. On the other hand, the H{infinity} control theory provides potential ability to overcome this problem. However, some limitations still exist in the treatment of uncertainty. That is, the existing standard H{infinity}-PSSs cannot adequately treat the system uncertainties. Moreover, performance problems can arise in this approach due to the pole-zero cancellation phenomenon. To deal with the above mentioned limitations, a new design methodology for H{infinity}-PSS based on the `numerator-denominator` uncertainty representation is ...

International Nuclear Information System (INIS)

Enhanced nutrient cycling basically involves close interaction between inorganic and organic sources of nutrients. Contrasting scenarios of nutrient cycling are found under intensive cropping production systems in most industrialized countries and traditional production systems predominant in many developing countries, where there is a net mining of soil nutrients due to crop harvest removal and erosion. Therefore, to enhance nutrient management in marginal tropical soils it is necessary to maximize the efficiency of nutrient uptake from various inorganic and organic sources with minimal environmental impact. It is postulated that one of the main approaches will be the identification and/or selection of plant genotypes for enhanced nutrient acquisition, in particular at low levels of soil available nutrients. In this context, use of various isotope techniques in examining root activity/distribution pattern and plant nutrient uptake is examined. ...

International Nuclear Information System (INIS)

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 capacity and distribution ...

International Nuclear Information System (INIS)

Analyses of the roles of cement-based barriers in radioactive waste isolation show that models used to estimate their characteristics during the lifetime of the repository must consider the alteration of material properties with time due to degradation processes. Reinforced concrete barriers at repositories shall be designed in such manner that they fulfil besides isolative capabilities also the required functions of mechanical resistance and stability. Key elements of safety evaluation are mainly the correct selection of materials for mineral composites with cement binder (cements, aggregates, mineral additives and chemical admixtures) and their design, execution of construction works and production of precast concrete containers (continuous casting of concrete - no cold joints, limited number of construction joints, proper placing and consolidation, finishing and curing), strict control of used materials and inspection of works, as well as ...

International Nuclear Information System (INIS)

Since 1992, the fruitful collaboration of the Russian and Western-European technical support organizations (TSOs) is being continued due to the support of the European Commission. There are two main areas of activities. The first one is more of methodological assistance and enhancing RF TSOs capabilities to support Rostekhnadzor decision making process. Experience and knowledge acquired in this area projects increase RF TSOs capabilities regarding a wide spectrum of safety related issues assessment, in particular safety analyses, reactor vessel embrittlement, application of 'leak before break' concept, severe accident and accident management, fire risk evaluation, etc. The second area is focused on licensing related assessments of EC financed on site assistance projects (modernisations). This area projects promote implementation in Russia a licensing process based on a technical dialogue between operator and regulator as ...

Energy Technology Data Exchange (ETDEWEB)

Experiences in hazardous materials transportation show that purely strategic or planning approaches have considerable shortcomings and that real-time management must be addressed. The commercialization of advanced location and communications technology provides the basis for real-time guidance. Considering the possibilities this new technology offers, a real-time routing model is proposed. It is based on the premises that a human dispatcher must assess the impacts of sudden events on safety and transportation costs and evaluate safe and cost-effective routing alternatives. Due to high uncertainty and time constraints in this real-time environment, risks and transportation costs are expressed as preferences on an ordinal scale. The model has been integrated into a decision support system and assessed in an experimental setting. This ordinal preference model turned out to be superior to a utility approach due to its ...

Energy Technology Data Exchange (ETDEWEB)

Due to changed operational conditions and because of the increasing age of several hydro power plant components, there is an increasing risk of damages and the control of degradation mechanisms is of increasing significance. Therefore lifetime considerations for safety relevant components in pumped-storage plants become more and more important. The development of a lifetime management system, in conjunction with monitoring systems and specific surveillance for a group of pumped-storage power plants of different ages and in a wide range of power output is presented. The special focus is on the impact of fatigue strength considerations within this framework. The applied procedure will be described for typical mechanical components in pumped-storage plants exemplarily. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Some motor operated valves now have higher torque switch settings due to regulatory requirements to ensure valve operability with appropriate margins at design basis conditions. Verifying operability with these settings imposes higher stem loads during periodic inservice testing. These higher test loads increase stresses in the various valve internal parts which may in turn increase the fatigue usage factors. This increased fatigue is judged to be a concern primarily in the valve disks, seats, yokes, stems, and stem nuts. Although the motor operators may also have significantly increased loading, they are being evaluated by the manufacturers and are beyond the scope of this study. Two gate valves representative of both relatively weak and strong valves commonly used in commercial nuclear applications were selected for fatigue analyses. Detailed dimensional and test data were available for both valves from previous studies at the Idaho National ...

Energy Technology Data Exchange (ETDEWEB)

During LOCA (Loss of Coolant Accident) in design bases accident (DBA), emergency core coolant supplements form a recirculation sump and cooled core and containment. When the double ended guillotine Break (DEGB) at the hot leg near steam generator, due to the jet impingement discharge flow, the debris could be potentially generated at pipe or wall nearby steam generator and be transported to the recirculation sump. Therefore, the debris, such as insulations and paint chips, could be accumulated and be clogged in the recirculation sump screen. If debris is blocked the sump strainer, the pressure drop is increased at the screen so as to increase the pressure loss of ECCS (Emergency Core Cooling System) pump NPSH (Net positive suction head). It is potentially influenced to decrease the long-term cooling capability of the recirculation sump. The recirculation sump screen clogging accident has happened in BWR of USA and Sweden. Considering the important to ...

Energy Technology Data Exchange (ETDEWEB)

The Stockpile Stewardship Program (SSP) is a single, highly integrated technical program for maintaining the safety and reliability of the U.S. nuclear stockpile. The SSP uses past nuclear test data along with current and future nonnuclear test data, computational modeling and simulation, and experimental facilities to advance understanding of nuclear weapons. It includes stockpile surveillance, experimental research, development and engineering programs, and an appropriately scaled production capability to support stockpile requirements. This integrated national program requires the continued use of current facilities and programs along with new experimental facilities and computational enhancements to support these programs. The Advanced Simulation and Computing Program (ASC)1 is a cornerstone of the SSP, providing simulation capabilities and computational resources to support the annual stockpile assessment and certification, to study advanced nuclear-weapons ...

International Nuclear Information System (INIS)

Current methods to calculate dose distributions with organ motion can be broadly classified as 'dose convolution' and 'fluence convolution' methods. In the former, a static dose distribution is convolved with the probability distribution function (PDF) that characterizes the motion. However, artifacts are produced near the surface and around inhomogeneities because the method assumes shift invariance. Fluence convolution avoids these artifacts by convolving the PDF with the incident fluence instead of the patient dose. In this paper we present an alternative method that improves the accuracy, generality as well as the speed of dose calculation with organ motion. The algorithm starts by sampling an isocenter point from a parametrically defined space curve corresponding to the patient-specific motion trajectory. Then a photon is sampled in the linac head and propagated through the three-dimensional (3-D) collimator structure corresponding to a particular MLC segment chosen randomly from ...

International Nuclear Information System (INIS)

Reduced-Moderation Water reactor (RMWR) is a light water breeder reactor developed by Japan Atomic Energy Research Institute (JAERI). The RMWR comprises tight lattice fuel assemblies with gap clearance of around 1.0 mm to reduce water volume ratio to achieve a high conversion ratio. It is important to estimate the thermal hydraulic safety margin of the tight lattice core of the RMWR. In the present study, the boiling transition (BT) prediction performance of the subchannel analysis code NASCA developed for the current BWR cores was assessed for series of tight lattice critical heat flux (CHF) experiments performed in JAERI. The test section was a 7-rod bundle with rod diameter of 12.3 mm, rod gap of 1.0 mm and heated length of 1.8m. Axial power distribution was flat. With a simple subchannel model, the code overestimates the critical power in the high mass velocity region, although the predicted critical powers in the low mass velocity region ...

Science.gov (United States)

AIDE (Activity and Internal Dose Estimates) is a software for calculating activities in compartments and committed doses due to occupational exposures, and for performing intake and dose estimates using bioassay data. It has been continuously developed and tested for more than 20 years. Its calculation core has been applied in several situations, like performing all dose estimates due to (137)Cs intakes, which occurred during the Goiania accident in 1987; performing quality assurance of the ICRP Task Group on Dose Calculations regarding calculations of activities in compartments and generation of dose coefficients for adults due to intakes by inhalation, ingestion and injection of several radionuclides; and producing the tables of activities in compartments and dose coefficients using the NCRP Wound Model for the NCRP report. It provides several capabilities like performing calculations using modified Human Respiratory ...

International Nuclear Information System (INIS)

Failure of multiple components due to a common cause represents one of the most important issues in evaluation of system reliability or unavailability. The frequency of such events has relatively low expectancy, when compared to random failures, which affect individual components. However, in many cases the consequence is a direct loss of safety system or mitigative safety function. For this reason, the modeling of a common cause failure (CCF) and its presentation in fault tree structure is of the uttermost importance in probabilistic safety analyses (PSA). Amongst the different techniques available to reduce the impact of common cause failures, the most important operations related technique, is that of staggered testing. In the TAPP 3,4 Level-1 PSA it was found that the contribution of Common Cause Failures to the Core Damage Frequency (CDF) was significant. The Common Cause Failures were modeled ...

Energy Technology Data Exchange (ETDEWEB)

Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation of the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code ...

Energy Technology Data Exchange (ETDEWEB)

Marginal fractures of the tibial plateau are associated with a high incidence of soft tissue injuries to the stabilising structures of the knee joint. Injuries to the anterior cruciate ligament are associated with the Segond fracture and impingement fractures of the posteromedial tibial plateau. Recognition of these fractures aids diagnosis of these injuries. Marginal fractures of the tibial plateau associated with posterior cruciate ligament injuries are less common, though recently a ''reverse'' Segond fracture has been recognised. We describe a fracture of the anteromedial tibial plateau associated with complete disruption of the posterior cruciate ligament and posterolateral complex. (orig.)

International Nuclear Information System (INIS)

The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky trademark pump feeds water to a lance that directs the high pressure water at the surface to be removed. The safety and health evaluation during the testing demonstration focused on two main areas of exposure. These were dust and noise. The dust exposure was found to be minimal, which would be expected due to the wet environment inherent in the technology, but noise exposure was at a significant level. Further testing for noise is ...

International Nuclear Information System (INIS)

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 analyzed. A comparison to non-time history ...

Science.gov (United States)

Government agencies responsible for protecting the public from the adverse effects of toxic chemicals must set priorities for research, regulatory action, protocol testing, and monitoring due to the vast number of toxic chemicals and the limited resources available to these agencies. The National Institute for Occupational Safety and Health (NIOSH) must set priorities for research on hazards encountered in the workplace. Priorities are also utilized by NIOSH in preparing criteria for recommended occupational standards which are forwarded to the Occupational Safety and Health Administration (OSHA), U.S. Department of Labor, for possible promulgation. For various reasons, including rapidly changing conditions in the American workplace, NIOSH has instituted a revised priorities program. In the future, NIOSH research and recommended standards activities will focus not only on individual chemicals, but also on industries, ...

International Nuclear Information System (INIS)

Four very common long term mineralogical changes in salt formations are discussed in the view of the safety considerations for underground repositories. Two of these processes, the 'Hartsalz' and 'Carnallite' dissolution were studied in two scale in situ experiments. The results are presented and compared with the results of the geochemical modelling with the computer code EQ3/6. Furthermore the reactions leading to the formation of the gypsum cap rock on the top of the Zechstein salt formations and to the polyhalitization of anhydrite are discussed. Geological field observations and mineral assemblages agree well with the results of the geochemical modelling employing the Pitzer formalism along with the Harvie, Moller and Weare database. We conclude that once the mechanisms of the chemical reactions are well understood it becomes possible to evaluate realistically whether such processes, when encountered in the repository, are still active or whether they are ...

Energy Technology Data Exchange (ETDEWEB)

One of the issues identified in the US Nuclear Regulatory Commission`s Nuclear Plant Aging Research program plan is the need to understand the state of ``mothballed`` or other out-of-service equipment to ensure subsequent safe operation. Programs for proper storage and preservation of materials and components are required by NRC regulations (10 CFR 50, Appendix B). However, materials and components have been seriously degraded due to improper storage, protection, or layup, at facilities under construction as well as those with operating licenses. Pacific Northwest Laboratory has evaluated management of aging for unstarted or mothballed nuclear power plants. The investigations revealed that no uniform guidance in the industry addresses reactor layup. In each case investigated, layup was not initiated in a timely manner, primarily because of schedule uncertainty. Hence, it is reasonable to assume that this delay resulted in accelerated aging of some ...

Science.gov (United States)

allowed an initial assessment of ADS-33 handling quality requirements for an aircraft of this ...... then executing 180 or 360 degree turns in an attempt to ...

Energy Technology Data Exchange (ETDEWEB)

Many mines and processing facilities are in remote, difficult to access areas, or are in areas where access is limited or restricted for national reasons. In a joint project with Canada Centre for Remote Sensing, the Canadian Safeguards Support Program is investigating utility of multi- and hyperspectral remote sensing for remotely inspecting such site. With a view to eventually using the hyperspectral satellite data now coming available, airborne data over uranium and copper mine tailings and uranium processing facilities in northern Canada were acquired. The objective of this work is to demonstrate that multispectral and hyperspectral data can provide complementary and supplementary information to high-resolution panchromatic imagery for the following safeguards applications: Inspection aids (up-to-date maps of remote locations), change detection, evaluation of member state declarations, monitoring of reactor, mining and processing facility operations, and detection of undeclared ...

Science.gov (United States)

The integrity and safety of beam-like structures are dependent in part on their boundary conditions which can vary with time due to damage or aging. Structural health monitoring of such structures should therefore include attention to boundary conditions. Where the boundary conditions can be represented by a lumped spring then the identification of associated stiffness parameter values may be a means to quantifying the integrity of the support. This paper investigates such a method for identifying the equivalent translational and rotational stiffness of a constrained tapered beam-like structure. An analytical model of a beam of tapered width and thickness is adopted as a simplified representation of a tower-like structure. The model is used to explore in what scenarios natural frequencies and/or nodal points might be sufficiently sensitive to changes in support conditions to be measurable indicators of damage. The method is evaluated by Monte ...

Energy Technology Data Exchange (ETDEWEB)

To make a quantitative comparison of risks between the SNR-300 and a modern PWR (Biblis B), the consequences of an accident or the extent of damage of a release of radionuclides to the environment due to an accident are estimated by computer programs for accident consequence models. The accident analysis includes an analysis of events for Bethe-Tait accidents with failure of the outer containment. The FGSB release rates are compared with those of the Society for Reactor Safety (GRS).

Energy Technology Data Exchange (ETDEWEB)

Traditional methane drainage methods, including conventional ventilation and boreholes drilled in the coal seam, are widely used in modern coal mining operation in China. However, it is often noted that the gas drainage presents low efficiency in most coal mines due to low permeability of the coal seam, which not only affects the safety, but also the productivity of the coal mine. This paper describes the development and application of the waterjet cutting system, which is used to create artificial fractures and increase the permeability of coal seam for the improvement of methane drainage in underground coal mines in China. According to underground monitoring, a significant improvement of methane drainage efficiency of up to 3 to 6 times over the traditional methods has been achieved. (author)

Science.gov (United States)

Electric utilities have been surprised by recent opposition to the construction of very-high-voltage transmission lines, which met with little resistance in the past. Concerns over health and safety factors are associated with the increase in the number of such lines, although their presence has always been an inconvenience and a hazard for those living and working in the immediate vicinity. The new lines present additional hazards due to the continuous flow of small electric currents and the charges that build up in the area of the towers and lines. The lines are also a threat to persons wearing cardiac pacemakers. There is experimental evidence from the Soviet Union and the U.S. that electric and magnetic fields at the frequencies of such power lines can have serious biological effects on growth rates and the functioning of the central nervous system. Full disclosure that possible risks are involved and the opportunity to avoid these risks is ...

British Library Electronic Table of Contents (United Kingdom)

Steel building frames are often analyzed for stability in an elastic way, while most of their columns behave inelastically at the buckling stage. Most column design provisions allow for inelastic behavior, but overall inelastic stability analysis is rarely performed. In this study the analysis philosophy is centered on the overall frame stability and its true safety factor. As many columns show inelastic behavior at the buckling stage, the proposed procedure takes due consideration of this fact. Once the overall buckling factor for the frame is obtained, individual column effective length factors, and their true slenderness ratios are computed, and used in the design relationships. This procedure circumvents the use of design nomographs and numerous formulas proposed in the past to allevia...

Energy Technology Data Exchange (ETDEWEB)

Short communication

International Nuclear Information System (INIS)

From view on Organization Behavior theory, the concept, development and affecting factors of safety culture are introduced. The focuses are on the establishment, development and management practice for safety culture at Daya Bay NPP. A strong safety culture, also demonstrated, has contributed greatly to improving performance at Daya Bay

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

Science.gov (United States)

PMID:17142595

Energy Technology Data Exchange (ETDEWEB)

The passive continental margin in the northern South China Sea is a weakly active area. It has been found to be favorable for large gas field development and also to be profitable for gas hydrate. The active faults, diapir structure, slump deposits, faults break of slopes, gas chimneys and sandstone of submarine fan, control the concentration of gas hydrate. Gas chimneys are widely distributed in the northern South China Sea. They supply the pathway for migration of deeper gas to gas hydrate stability zones especially in the basin of tectonic inactive zone. This paper discussed the geological structures of gas hydrate occurrence in gas fields and presented a detailed analysis of gas chimneys within the northern slope of the South China Sea. The paper described the geological setting of the Qiongdongnan Basin and provided information on the data description and processing. Two multichannel seismic (MCS) reflection profiles were used for the study. In order to ...

International Nuclear Information System (INIS)

The purpose of this study was to clarify the benefits of digital lateral chest radiogram. In the basic study, the modulation transfer factor (MTF) and the wiener spectra (WS) of conventional screen film (CSF) and Fuji computed radiography (FCR) were measured. The visibility of the simulated nodules on FCR using 3 human bodies was subjectively compared with that on CSF by 13 observers. In the clinical study, the visibility of the normal structures on FCR was subjectively compared with that on CSF using 50 lateral chest radiograms by 10 observers. The diagnostic performance to detect pulmonary nodules on FCR was also compared with that on CSF using each 30 positive and negative cases by 8 observers. In the basic study, the MTF of FCR was superior to that of CSF, and the WS of FCR displayed in half size was superior to that of CSF. In all exposure conditions, the visibility of the nodules on FCR in the pulmonary apex was inferior to that on CSF, while FCR was superior to CSF in the other ...

International Nuclear Information System (INIS)

The effects of extended source-to-surface distance (SSD) on the electron beam dose profiles were evaluated for various electron beam energies - 6, 9, 12, 15 and 20 MeV - and the accuracy of various output correction methods was analysed on a Mitsubishi linear accelerator using a radiation field analyser (RFA). The dose fall-off region of the central axis depth-dose curves was nearly independent for SSDs up to 120 cm where as in the build-up region, a marginal reduction of surface dose was observed, particularly for lower energies and for smaller field sizes. Effective SSDs and virtual source distances were evaluated for field sizes ranging from 5x5 to 15x15 cm"2 for various energies. Curve fitting was done with the measured outputs with various equations and coefficients were evaluated. The accuracy of the derived output correction factors by effective SSD, virtual source distance and curve-fit methods was assessed by evaluating correlation coefficients between the ...

International Nuclear Information System (INIS)

Nuclear Fuel Plant (FCN) is a facility that produces fuel bundles of CANDU-6 type for the CANDU nuclear power plant. Only natural and depleted uranium in bulk and itemized form are present as nuclear materials in this facility. Uranium and wastes from the plant are handled, processed, treated and stored throughout the entire facility. The nuclear materials with natural and depleted uranium are entirely under nuclear safeguards. The amount of uranium present in the plant in different forms and activities together with zircaloy, beryllium and other hazardous substances, wastes, explosive materials at high temperatures, etc. lead to special measures undertaken by Nuclear Safety Department (DNS) to ensure nuclear safety. Different aspects of safety are continuously monitored in the plant: operational safety, industrial safety, radiological safety, labour ...

International Nuclear Information System (INIS)

To estimate the success criteria of an operator's action time for a probabilistic safety/risk assessment (PSA/PRA) of a nuclear power plant, the information from a safety analysis report (SAR) and/or that by using a simplified simulation code such as the MAAP code has been used in a conventional PSA. However, the information from these is often too conservative to perform a realistic PSA for a risk-informed application. To reduce the undue conservatism, the use of a best-estimate thermal hydraulic code has become an essential issue in the latest PSA and it is now recognized as a suitable tool. In the same context, the 'ASME PRA standard' also recommends the use of a best-estimate code to improve the quality of a PSA. In Korea, a platform to use a best-estimate thermal hydraulic code called the MARS code has been developed for the PSA of the Korea standard nuclear power plant (KSNP). This study has proposed an estimation method for an operator's ...

Energy Technology Data Exchange (ETDEWEB)

Surface structure analysis, i.e. metallographic analysis of component surfaces with the aid of replicas, is an established method of component monitoring and the only reliable non-destructive method for detecting and analyzing beginning creep damage in the form of creep pores. Creep pore development provides a basis for component condition analysis. It must be noted, however, that the modern martensitic 9-12 % Cr steels - like the established steels 10CrMo9-10 (P22) und X20CrMoV12-1 - have comparatively high creep fracture deformation rates in fatigue tests. This raises the question if these steels can be judged on the basis of data for established steels. The results so far suggest that even with low pore densities (single pores), a higher degree of damage and a shorter time until failure must be assumed. [German] Eine bewaehrte Methode der Bauteilueberwachung stellt die Oberflaechengefuegeuntersuchung, d. h. die metallografische Untersuchung der Bauteiloberflaeche mit Hilfe von ...

International Nuclear Information System (INIS)

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 ...

Science.gov (United States)

B-cell Chronic Lymphocytic Leukemia; Nodal Marginal Zone B-cell Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Small Lymphocytic Lymphoma; Splenic Marginal Zone Lymphoma; Waldenstrom Macroglobulinemia

British Library Electronic Table of Contents (United Kingdom)

Abstract Purpose: The aim of this in vitro study was to compare the marginal adaptation of a pressed ceramic material, when used with and without a metal substructure, to a traditional feldspathic porcelain-fused-to-metal restoration with a porcelain butt margin. Materials and Methods: A maxillary central incisor typodont tooth was prepared with a 1.5 mm 360degree shoulder with rounded internal line angle, and 30 polyether impressions were made. Dies were poured in type IV dental stone, and 30 restorations were fabricated: 10 metal ceramic restorations (MCR) with porcelain butt joints, 10 pressed to metal restorations (PTM), and 10 all-ceramic restorations (PCR). All restorations were evaluated on their respective dies at 45x magnification using an Olympus SZX-12, measurements of the margi...

UK PubMed Central (United Kingdom)

A Z-plasty is a critical and reliable technique that is useful for scar revisions and correction of free margin distortion. A Z-plasty can help lengthen a contracted scar, change the direction of a...Full Text Available

UK PubMed Central (United Kingdom)

A 72-year-old male presented with a large ulceroproliferative lesion over left gluteal region. After histopathological confirmation of squamous cell carcinoma, the lesion was excised with wide margins....Full Text Available

Science.gov (United States)

Present methods for planning reliability improvement of launch vehicles are reviewed. A theoretical criterion for optimum allocation of resources for reliability improvement exists that requires equal marginal failure reduction for all elements to be impr...

International Nuclear Information System (INIS)

We show the existence of a rather general class of closed cosmological models of Bianchi type IX that do not exhibit recollapse but expand for all times. This is despite the fact that these models satisfy the strong energy condition by a wide margin.

UK PubMed Central (United Kingdom)

BackgroundWide resection with tumor-free margins is necessary in soft-tissue sarcomas to minimize local recurrence and to contribute to long-term survival. Information about treatment...Full Text Available

International Nuclear Information System (INIS)

This paper shows that a stochastic regime-switching model can represent the volatile behavior of wholesale electricity prices associated with price spikes effectively. The structure of the model is very flexible because the mean prices in the two regimes and the two transition probabilities are functions of the load and/or the implicit reserve margin. Using price data from the single settlement market in PJM (May 1999 to May 2000), the results show that the estimated switching probability from the low to the high regime predicts price spikes well if the reserve margin is measured accurately.

International Nuclear Information System (INIS)

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)

International Nuclear Information System (INIS)

Greenland is the world's largest island, with an area of 2.2 million square kilometres, 80 % of which is covered by the ice sheet. The climate is Arctic, but as Greenland stretches 2600 km from north to south, there is a huge variability in climate, with temperature decreasing from south to north. Due to the influence of oceanic currents, the west coast is slightly warmer than the east coast. Precipitation also decreases strongly from the south to the north, and also with distance from the coast. Kangerlussuaq is located in the dry, continental area of central west Greenland. The bedrock of Greenland is dominated by Precambrian gneisses, with sedimentary rocks occurring in some areas of East and North Greenland, and smaller areas of basalts. All of Greenland has been glaciated several times and has thus been eroded and shaped by the ice, as it still is at the ice margin. Soils are generally thin, and especially in the gneiss regions rather poor ...

Energy Technology Data Exchange (ETDEWEB)

The integrity of the RPV head and reactor internals was assessed by means of fluid-structural analyses using a coupled method to evaluate the water hammer phenomenon arising from high burnup fuel failure under RIA conditions. The fluid viscosity effect on the water column burst as well as the complex three-dimensional flow paths caused by a core shroud and standpipes were considered in this study. The three analysis scenarios were designed to investigate the above mentioned influential factors separately. In the first scenario, a two-dimensional axisymmetric reactor vessel model without any reactor internals was modeled to assess the influence of the fluid dynamics in the NSC RIA regulatory evaluation. This model has an actual RPV geometry and can be simply separated from other influential factors in order to concentrate only on investigation of the fluid viscosity effect. In the second scenario, a two-dimensional axisymmetric reactor vessel model with major reactor internals, such as ...

Energy Technology Data Exchange (ETDEWEB)

This report reviews system safety analysis methods and examines their application to nuclear waste management systems. The safety analysis methods examined include expert opinion, maximum credible accident approach, design basis accidents approach, hazard indices, preliminary hazards analysis, failure modes and effects analysis, fault trees, event trees, cause-consequence diagrams, G0 methodology, Markov modeling, and a general category of consequence analysis models. Previous and ongoing studies on the safety of waste management systems are discussed along with their limitations and potential improvements. The major safety methods and waste management safety related studies are surveyed. This survey provides information on what safety methods are available, what waste management safety areas have been analyzed, and what are potential areas ...

Science.gov (United States)

familiarity fire triangle (i.e., fuel, oxidant, and ignition source) are excluded. It Is obvious that for the baseline safety goal for spacecraft this ...

Energy Technology Data Exchange (ETDEWEB)

Recommendations of the Advisory Committee on Reactor Safeguards are presented to the Commissioners for their consideration for FY 82 budget for the NRC safety research program.

International Nuclear Information System (INIS)

AECL Publications on Reactor Safety in CANDU Reactors are listed in this bibliography. The listing is chronological and the accompanying index is by subject. The bibliography will be brought up to date annually. (auth).

International Nuclear Information System (INIS)

Metastable austenitic steels show excellent mechanical properties, such as high strength combined with excellent ductility and toughness due to martensitic transformation under mechanical loading (transformation induced plasticity effect). A good energy consumption, and, in the case of high-alloyed metastable austenitic steels, a high corrosion resistance, increase the potential of these materials for diverse applications, also in regard of safety requirements. Up to now, numerous wrought alloys were investigated concerning mechanical behaviour, TRIP-effect, martensitic transformation behaviour and modelling of transformation kinetics or stress-strain behaviour. New high alloyed cast CrMnNi-steels, developed at Technical University Bergakademie Freiberg, provide the chance to reduce processing steps, production time and costs. In order to understand the influence of temperature on the martensitic phase transformation behaviour and therefore on ...

International Nuclear Information System (INIS)

The International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) was launched in the year 2000, based on a resolution by the IAEA General Conference (GC(44)/RES/21). INPRO intends to help to ensure that nuclear energy is available in the 21st century in a sustainable manner, and seeks to bring together all interested Member States, both technology holders and technology users, to consider, jointly, actions to achieve desired innovations. INPRO is taking care of the specific needs of developing countries. This IAEA publication is part of Phase 1 of INPRO. It intends to provide an overview on history, present situation and future perspectives of nuclear fuel cycle technologies. While this overview focuses on technical issues, nevertheless, the aspects of economics, environment, and safety and proliferation resistance are important background issues for this study. After a brief description about the INPRO project and an evaluation of existing and ...

Energy Technology Data Exchange (ETDEWEB)

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 report we discuss ...

Energy Technology Data Exchange (ETDEWEB)

As a result of health and safety issues surrounding the use of radioactive materials on coated optical components, there has been renewed interest in coating materials whose optical and mechanical properties approach those offered by their radioactive counterparts. Due to the radioactive nature of ThF{sub 4} and its widespread use in optical coatings, the coating industry is examining other low index and non-radioactive fluorides as possible alternatives. In this paper, the authors present the results of an experimental study on the optical and mechanical properties of thermally evaporated ThF{sub 4}, DyF{sub 3}, CeF{sub 3}, LiF, HfF{sub 4}, IRX, and IRB thin films, where the materials were deposited at different substrate temperatures. The objective is to examine this series of fluorides under comparable deposition conditions and with respect to such material properties as: n and k, film stress, and environmental stability. The optical ...

Energy Technology Data Exchange (ETDEWEB)

High-voltage transmission lines can be just as safe as the electrical wiring in the homes--or just as dangerous. The crucial factor is ourselves: they must learn to behave safely around them. This booklet is a basic safety guide for those who live and work around power lines. It deals primarily with nuisance shocks due to induced voltages, and with potential electric shock hazards from contact with high-voltage lines. References on possible long-term biological effects of transmission lines are shown. In preparing this booklet, the Bonneville Power Administration has drawn on more than 50 years of experience with high-voltage transmission. BPA operates one of the world`s largest networks of long-distance, high-voltage lines. This system has more than 400 substations and about 15,000 miles of transmission lines, almost 4,400 miles of which are operated at 500,000 volts.

Energy Technology Data Exchange (ETDEWEB)

The Hebron offshore drilling project in Atlantic Canada was discontinued in 2002 due to economic challenges. Chevron-Texaco has conducted small-scale studies to find ways to improve the project's viability. One of the main challenges facing this offshore drilling project is the issue of iceberg scour and its effect on seafloor equipment. This paper demonstrates how advances in ice engineering have resulted in new and cost-effective development concepts for: central gravity base structures; wellhead gravity base structures; floating production, storage and offloading (FPSO) subsea facilities; and, long subsea tieback and trench optimization. New studies have provided a better understanding of ice contact pressures, drift velocities, iceberg management and interaction processes. New designs for gravity base structures can reduce wave loads. The selection of a new development concept is determined by economic viability, capital cost, operability, technical ...

International Nuclear Information System (INIS)

The Fast Flux Test Facility (FFTF) is a liquid-metal-cooled test reactor located on the Hanford Site. The FFTF is the only reactor of this type designed and operated with the intent of meeting the licensing requirements of the Nuclear Regulatory Commission (NRC). Unique characteristics of the FFTF that present special challenges related to leak rate testing include thin wall containment vessel construction, cover gas systems that penetrate containment, and a low-pressure design basis accident. The successful completion in 1986 of the third FFTF Integrated Leak Rate Test (ILRT) five days ahead of schedule and 10% under budget was a major achievement for the Westinghouse Hanford Company. The success of this operational safety test was due in large part to a special local area network (LAN) of three IBM PC/XT computers that monitored the sensor data, calculated the containment vessel leak rate, and displayed test results. The multiple computer ...

International Nuclear Information System (INIS)

Tritium, a beta emitting gas at room temperature causes a biological hazard in the locations where it is present beyond acceptable limits. The hazard can be due to inhalation, and absorption by skin. Hence is the necessity of Tritium monitoring instruments/systems for ensuring safety in the PHWRs and the nuclear research plants and laboratories. It is desirable that the instruments address satisfactorily to certain factors like the following: (i) Wide range of Tritium concentrations - 1 to 104 DAC ( Derived Air Concentration) (ii) On-line monitoring features (iii) Small response time (On-spot instantaneous measurements) (iv) Portability (v) Mitigation of memory effects. This paper presents an overview of the Online Tritium in Air Monitoring Systems manufactured by ECIL for Pressurised Heavy Water Reactors at Tarapur, Kaiga, and Rawatbhata. Significant aspects of design, function, testing, limitations of the detectors and electronics and the ...

Energy Technology Data Exchange (ETDEWEB)

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 cladding tubes in PWRs. Recently, accompanying the advance of LWR technology, the ...

Energy Technology Data Exchange (ETDEWEB)

Production of hydrogen sulfide in produced waters due to the activity of sulfate-reducing bacteria (SRB) is a potentially serious problem. The hydrogen sulfide is not only a safety and environmental concern, it also contributes to corrosion, solids formation, a reduction in produced oil and gas values, and limitations on water discharge. Waters produced from seawater-flooded reservoirs typically contain all of the nutrients required to support SRB metabolism. Surface processing facilities provide a favorable environment in which SRB flourish, converting water-borne nutrients into biomass and H{sub 2}S. This paper will present results from a field trial in which a new technology for the biochemical control of SRB metabolism was successfully applied. A slip stream of water downstream of separators on a produced water handling facility was routed through a bioreactor in a side-steam device where microbial growth was allowed to develop fully. This ...

Energy Technology Data Exchange (ETDEWEB)

Marketing of minimally processed vegetables (MPV) are gaining impetus due to its convenience, freshness and apparent health effect. However, minimal processing does not reduce pathogenic microorganisms to safe levels. Food irradiation is used to extend the shelf life and to inactivate food-borne pathogens. In combination with minimal processing it could improve safety and quality of MPV. A microbiological screening method based on the use of direct epifluorescent filter technique (DEFT) and aerobic plate count (APC) has been established for the detection of irradiated foodstuffs. The aim of this study was to evaluate the applicability of this technique in detecting MPV irradiation. Samples from retail markets were irradiated with 0.5 and 1.0 kGy using a {sup 60}Co facility. In general, with a dose increment, DEFT counts remained similar independent of the irradiation while APC counts decreased gradually. The difference of the two counts ...

Energy Technology Data Exchange (ETDEWEB)

In this article two integral computational fluid dynamics methods for steady-state and transient vehicle aerodynamic simulations are described using a Chevrolet Corvette ZR-1 surface panel model. In the last decade, road-vehicle aerodynamics have become an important design consideration. Originally, the design of low-drag shapes was given high priority due to worldwide fuel shortages that occurred in the mid-seventies. More recently, there has been increased interest in the role aerodynamics play in vehicle stability and passenger safety. Consequently, transient aerodynamics and the aerodynamics of vehicle in yaw have become important issues at the design stage. While there has been tremendous progress in Navier-Stokes methodology in the last few years, the physics of bluff-body aerodynamics are still very difficult to model correctly. Moreover, the computational effort to perform Navier-Stokes simulations from the geometric stage to complete ...

International Nuclear Information System (INIS)

Full text: Full text: The incomplete understanding of the complex mechanisms connected with the interaction between thermal-hydraulic and neutron kinetics still challenges the design and the operation of nuclear reactors and imposes the adoption of conservatism in the evaluation of safety limits. The recent availability of powerful computer and computational techniques together with the continuing increase in operational experience suggests the revisiting of those areas and the identification of design/operation requirements that can be relaxed. So far, almost all of the safety analyses of research reactors have been performed using conservative computational tools such as channel codes but, nowadays, the application of Best-Estimate (BE) methods constitutes a real necessity. The global aim of the current work is an attempt to apply the best-estimate system thermal-hydraulic code Relap5. For this purpose, the generic IAEA research reactor ...

International Nuclear Information System (INIS)

Several nuclear power plant sites have been wounded in the crossfire between two distinct corporate cultures. The traditional utility culture lies on one side and that of the nuclear navy on the other. The two corporate cultures lead to different perceptions of open-quotes safety culture.close quotes This clash of safety cultures obscures a very important point about nuclear plant operations: Safety depends on organizational learning. Organizational learning provides the foundation for a perception of safety culture that transcends the conflict between utility and nuclear navy cultures. Corporate culture may be defined as the knowledge, attitudes, and beliefs shared by employees of a given company. Safety culture is the part of corporate culture concerning shared attitudes and beliefs affecting individual or public safety. If the safety ...

Energy Technology Data Exchange (ETDEWEB)

Grain refinement behavior of copper alloys cast in permanent molds was investigated. This is one of the least studied subjects in copper alloy castings. Grain refinement is not widely practiced for leaded copper alloys cast in sand molds. Aluminum bronzes and high strength yellow brasses, cast in sand and permanent molds, were usually fine grained due to the presence of more than 2% iron. Grain refinement of the most common permanent mold casting alloys, leaded yellow brass and its lead-free replacement EnviroBrass III, is not universally accepted due to the perceived problem of hard spots in finished castings and for the same reason these alloys contain very low amounts of iron. The yellow brasses and Cu-Si alloys are gaining popularity in North America due to their low lead content and amenability for permanent mold casting. These alloys are prone to hot tearing in permanent mold casting. Grain refinement is one of the ...

Energy Technology Data Exchange (ETDEWEB)

The use of standard cementitious material creates pulses of pH in the magnitude of 12-13 in the leachates and release alkalis. Such a high pH is detrimental and also unnecessarily complicates the safety analysis of the repository. As no reliable pH-plume models exist, the use of products giving a pH below 11 in the leachates facilitates the safety analysis. Also, according to current understanding, the use of low-pH cement (pH = 11) will not disturb the functioning of the bentonite, although limiting the amount of low-pH cement is recommended. A result of the project is that there are both low-pH cementitious material for grouting larger fractures (= 100 {mu}m) and non-cementitious material for grouting smaller fractures (< 100 {mu}m) that will, after further optimisation work, be recommended for grouting of deep repositories. This project concentrated on the technical development of properties for the low pH grouts. Long-term ...

International Nuclear Information System (INIS)

Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.

British Library Electronic Table of Contents (United Kingdom)

Abstract Overall Numbers Small, But Study Finds SSRI Exposure, Autism Link Additional Drug Safety, Efficacy Data Needed for Pediatric Bipolar Disorder SGA Safety and Efficacy in Children and Adolescents Aripiprazole Safety and Tolerability for Irritability in Autism No Lisdexamfetamine Effect on Sleep Disturbances in Children With ADHD Sickle Cell Disease With Comorbid Depression Homeopathy in Psychiatry Manic Symptoms Induced by Marijuana in a Healthy Adolescent New Warnings Safety Labeling Changes

Energy Technology Data Exchange (ETDEWEB)

The relations between nuclear energy availability and nuclear plant safety are analyzed in the particular cases of naval propulsion nuclear boilers (aircraft carriers, submarines): safety objectives, present and potential risk analysis, optimization of the availability-safety couple, at the design stage and during operation (procedural rules related to the boiler state, real time decisions). 6 fig., 1 tab.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

This paper will review code and standard and the safety related features of major components of Monju: Components of the Reactor Coolant Boundary; Components of the Reactor Shurdown Systems; Components of the Decay Heat Removal Systems; Components of the Engineered Safety Features; Other Safety Related Components. Their relationship to the system or plant function is emphasized, in reviewing these components.

Energy Technology Data Exchange (ETDEWEB)

This Safety Analysis Report (SAR) is prepared in compliance with the requirements of DOE Order 5480.23, Nuclear Safety Analysis Reports, and has been written to the format and content guide of DOE-STD-3009-94 Preparation Guide for U. S. Department of Energy Nonreactor Nuclear Safety Analysis Reports. The Hot Cell Facility is a Hazard Category 2 nonreactor nuclear facility, and is operated by Sandia National Laboratories for the Department of Energy. This SAR provides a description of the HCF and its operations, an assessment of the hazards and potential accidents which may occur in the facility. The potential consequences and likelihood of these accidents are analyzed and described. Using the process and criteria described in DOE-STD-3009-94, safety-related structures, systems and components are identified, and the important safety functions of each SSC are described. Additionally, ...

International Nuclear Information System (INIS)

This paper explores the current trends in development of technology-neutral safety requirements to be used in the regulation of future nuclear power reactors and the role of the quantitative safety goals in the design of reactor safety systems. Establishing the requirements concerning the reliability of safety functions rather than on particular systems employed to achieve the functions, as well as the use of the recommendations of the International Commission on Radiological Protection (ICRP) on protection against potential exposure could form the basis of a technology-neutral framework for safety requirements on new reactor designs. Also it could contribute to international harmonisation of nuclear safety assessment practices as part of the licensing processes for future nuclear power plants. (author)

International Nuclear Information System (INIS)

The term 'Post-CHF' was generally used in the two-phase flow regime in tube flow occurring downstream of the CHF. It has various other names such as dispersed flow, liquid-deficient flow, mist flow and film boiling because the two-phase regime is characterized by a continuous vapor phase with discrete liquid drops and a non-wetted heated surface. The regime has been adopted in a lot of applications including nuclear power plants, fossil power plants, steam generators, refrigeration systems and spray cooling, In particular, this regime has a considerable importance in the areas of light water reactor(LWR) accident analysis (off-normal operating conditions) and design in heat exchangers operating in the once-through mode where subcooled liquid enters the exchanger and superheated vapor exits. Recently, innovative PWRs adopt very high power density increases and so require increased safety margins. For instance, advanced PWRs would be going to use ...

International Nuclear Information System (INIS)

The Programmable Logic Controller (PLC) for use in Nuclear Power Plant safety-related applications is being developed and tested first time in Korea. This safety-related PLC is being developed with requirements of regulatory guideline and industry standards for safety system. To test that the quality of the developed PLC is sufficient to be used in safety critical system, document review and various product testings were performed over the development documents for S/W, H/W, and V/V. This paper provides the performance testing methodology and its effectiveness for PLC platform conducted by KOPEC

International Nuclear Information System (INIS)

Since its creation the nuclear industry has been struggling with the question of how safe is safe enough. Safety is a common goal to all involved in the design, operation and regulation of a nuclear installation. As a concept safety is not easy to define. However, there is a general understanding of what attributes a nuclear power plant should have in order to operate safely. The challenge lies in measuring the attributes. The new competitive open electricity market, in many countries throughout the world, is increasing the economic pressure on operators to lower operating costs without jeopardizing safety. Challenges are occurring at a rate that is unprecedented in the nuclear industry: competitiveness; downsizing; ageing; policy changes; reorganization; restructuring; mergers; globalization; and takeovers demand increasing attention to the management of safety. There are various means to measure ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents the conceptual framework that is being used to define quantification of margins and uncertainties (QMU) for application in the nuclear weapons (NW) work conducted at Sandia National Laboratories. The conceptual framework addresses the margins and uncertainties throughout the NW life cycle and includes the definition of terms related to QMU and to figures of merit. Potential applications of QMU consist of analyses based on physical data and on modeling and simulation. Appendix A provides general guidelines for addressing cases in which significant and relevant physical data are available for QMU analysis. Appendix B gives the specific guidance that was used to conduct QMU analyses in cycle 12 of the annual assessment process. Appendix C offers general guidelines for addressing cases in which appropriate models are available for use in QMU analysis. Appendix D contains an example that highlights the consequences of different ...

International Nuclear Information System (INIS)

The Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory was designed with some passive safety response attributes which contribute to the safety of the facility. The three passive safety attributes being evaluated in the paper are: 1) In-core and in-vessel natural convection cooling, 2) a passive heat sink capability of the ATR primary coolant system (PCS) for the transfer of decay power from the uninsulated piping to the confinement, and 3) gravity feed of emergency coolant makeup. The safety significance of the ATR passive safety response attributes is that the reactor can passively respond to most transients, given a reactor scram, to provide adequate decay power removal and a significant time for operator action should the normal active heat removal systems and their backup systems both fail. The ATR Interim Level 1 Probabilistic Risk Assessment (PRA) models ...

Science.gov (United States)

BACKGROUND: The urgent need for patient safety education for healthcare students has been recognised by many accreditation bodies, but to date there has been sporadic attention to undergraduate/graduate medical programmes. Medical students themselves have identified quality and safety of care as an important area of instruction; as future doctors and healthcare leaders, they must be prepared to practise safe healthcare. Medical education has yet to fully embrace patient safety concepts and principles into existing medical curricula. Universities are continuing to produce graduate doctors lacking in the patient safety knowledge, skills and behaviours thought necessary to deliver safe care. A significant challenge is that patient safety is still a relatively new concept and area of study; thus, many medical educators are unfamiliar with the literature and unsure how to integrate ...

Energy Technology Data Exchange (ETDEWEB)

The studied coal bearing series has a parallel origin. The following facial complexes are isolated in its composition: lakes free of vegetation without coal interlayers; overgrown lakes of their margins which are poor in coals; swampy lakes, whose peat beds formed coal layers of shallow or moderate depth; channel sediments without coal layers and swamps from between channel spaces which created thick coal strata of high quality for which, however, a strong changeability in thickness is intrinsic. The coal strata are normally split towards the central parts of the lake basins and river channels. The coal presence of the suite is reduced along the section which is associated with the replacement of the lake swamp conditions of sedimentation by lake river conditions. A paleotectonic analysis established that the distribution of the zones richest in coal was controlled by consedimentational structural elements.

Energy Technology Data Exchange (ETDEWEB)

The return on investment for the chemical/petrochemical industrial is getting worse in comparison with other industrials. For example, in the last five years, the NASDAQ index has increased its value from 770 to 2200 (314%). Especially, in the areas of internet business, certain stock values has increased by five time in less than 3 years. However, the average changes in stock values for the chemical/petrochemical/oil industrials are between -50% to +230%. This is far too small for the expectation of today`s investors. Consequently, many companies diversified to pharmaceutical business where the profit margins are higher. Lately there have been many mergers for a better share of capitals and manpower, hence improving the profit margins. However, what is the bottom-line problems? What role can process integration play to better our future? (au)

Energy Technology Data Exchange (ETDEWEB)

A section of the northern margin of the Guineo-Congolian rain forest of the Central African Republic is studied to determine to what extent deforestation is evolving. Three sites are presented to highlight the diversity in local environmental settings at the northern margin of the closed equatorial rain forest: the contiguous equatorial rain forest, the boundary between the closed rain forest and the grasslands, and a predominantly secondary grassland environment. Proven image processing procedures for determining land cover and vegetation vigor were applied to Landsat MSS data to determine land cover characteristics and identify alterations in land cover that indicate potentially degraded forest environments. Land cover was independently assessed using spectral signatures determined from a statistical clustering routine. The images presented and image analyses contribute insights and information to an ongoing effort to determine more reliable ...

DEFF Research Database (Denmark)

This paper analyses the relationship between production subsidies and firms" export performance using a very comprehensive and recent firm-level database and controlling for the endogeneity of subsidies. It documents robust evidence that production subsidies stimulate export activity at the intensive margin, although this effect is conditional on firm characteristics. In particular, the positive relationship between subsidies and the intensive margin of exports is strongest among profit-making firms, firms in capital-intensive industries, and those located in non-coastal regions. Compared to firm characteristics, the extent of heterogeneity across ownership structure (SOEs, collectives, and privately owned firms) proves to be relatively less important

Energy Technology Data Exchange (ETDEWEB)

A Lawrence Livermore National Laboratory (LLNL) Management Pre-Start Review (MPR) Team was formed to independently verify the operational readiness of Building 368 (B368) Biosafety Level III (BSL-3) Facility to conduct research with biological pathogens and toxins including those considered Select Agents. Review objectives and criteria were developed from the DOE/NNSA and LLNL requirements. These were provided in the Implementation Plan for the Biosafety Level III (BSL-3) Facility Management Pre-Start Review (BSL-3 MPR) at Lawrence Livermore National Laboratory that was reviewed and approved by DOE/NNSA-LSO. The formal part of the LLNL MPR for the BSL-3 Facility was begun in August of 2005 but work on the MPR was stopped in October of 2005 due to the need for LLNL to reassess organizational and operational controls and respond to Centers for Disease Control and Prevention inquiries related to a shipping incident involving select agents. The MPR was restarted in ...

International Nuclear Information System (INIS)

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 ...

Energy Technology Data Exchange (ETDEWEB)

The Petroleum Technology Transfer Council (PTTC) and cooperating Regional Lead Organizations (RLOs) in its South Midcontinent (Oklahoma Geological Survey, Norman, Oklahoma) and West Coast (University of Southern California, Los Angeles, California) regions conducted a ''Mentor-Based Effort to Advance Implementation of Preferred Management Practices (PMPs) For Oil Producers'' (DE-FC26-01BC15272) under an award in Phase I of Department of Energy's (DOE's) PUMP (Preferred Upstream Management Practices) program. The project's objective was to enable producers in California, Oklahoma and Arkansas to increase oil production, moderating or potentially reversing production declines and extending the life of marginal wells in the near term. PTTC identified the primary constraints inhibiting oil production through surveys and PUMPer direct contacts in both regions. The leading common constraint was excess ...

International Nuclear Information System (INIS)

Immunoassays are versatile analytical techniques that had a leading role in various clinical applications, during the last four decades. The studies carried out by Rosalyn Yalow, Solomon Berson and Roger Ekins in the 1960s gave a breakthrough in the development of this novel analytical method. Sensitivity up to femtomolar concentrations, high specificity and universal application to different classes of molecular species made immunoassay a very useful tool in analytical investigation. The expertise acquired by immunochemists in producing antibodies against any antigen and the ability of radiochemists in labeling the antigens with "1"2"5I without affecting the active site are the two main factors responsible for the above development. There are concerns about the safety and health of humans due to the high-level contamination of environment by pesticides, industrial compounds and metals, anabolic steroids in milk and meat products, and presence ...

UK PubMed Central (United Kingdom)

BackgroundSafety for diabetic patients means providing the most suitable treatment for each type of diabetic in order to improve monitoring and to prevent the adverse effects of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The Plutonium Finishing Plant (PFP) previously known as the Plutonium Process and Storage Facility, or Z-Plant, was built and put into operation in 1949. Since 1949 PFP has been used for various processing missions, including plutonium purification, oxide production, metal production, parts fabrication, plutonium recovery, and the recovery of americium (Am-241). The PFP has also been used for receipt and large scale storage of plutonium scrap and product materials. The PFP Final Safety Analysis Report (FSAR) was prepared by WHC to document the hazards associated with the facility, present safety analyses of potential accident scenarios, and demonstrate the adequacy of safety class structures, systems, and components (SSCs) and operational safety requirements (OSRs) necessary to eliminate, control, or mitigate the identified hazards. Documented in this Safety Evaluation Report (SER) ...

International Nuclear Information System (INIS)

Nuclear power plant has several safety features and each safety feature is based on the operation of pumps and valves. Therefore, it is an essential basis for the safety of nuclear power plant to keep operational readiness of pumps and valves by In-Service Test (IST). According to Ministry of Education, Science and Technology (MEST) Bulletin 2008-14, the safety functioned pumps and valves of all nuclear power plants of Korea Hydro and Nuclear Power Co. Ltd.(KHNP) have been tested to verify their performance of safety function. Each safety grade pump has own design requirement and should be tested to identify whether it could meet the requirement. Design requirements and test references of all safety grade pumps of Wolsung Nuclear Power Plant Unit 2 (Wolsung Unit 2) were examined in this study. And the results of the performance test of the ...

Science.gov (United States)

This report is designed to cover the overall Operation Castle radiological safety matters from the viewpoint of those issues of direct concern to Headquarters, Joint Task Force Seven. It was written for the express purpose of assisting in the development ...

Energy Technology Data Exchange (ETDEWEB)

This report includes the issuances received during the specified period from the Commission (CLI), the Atomic Safety and Licensing Appeal Boards (ALAB), the Atomic Safety and Licensing Boards (LBP), the Administrative Law Judge (ALJ), the Directors' Decisions (DD), and the Denials of Petitions for Rulemaking (DPRM).

UK PubMed Central (United Kingdom)

Telbivudine is a novel nucleoside drug recently approved for the treatment of patients with chronic hepatitis B. Its nonclinical safety was evaluated in a comprehensive program of studies, including...Full Text Available

UK PubMed Central (United Kingdom)

A workshop on alternative toxicological testing methodologies was convened by the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC) 26-31 January 1997 in Ispra, Italy,...Full Text Available

Science.gov (United States)

The Global Road Safety Partnership (GRSP) is a global partnership of business, civil society and government working for sustained reduction of road accidents in developing and transition countries. GRSP, which started operations in 1999, has a global secr...

UK PubMed Central (United Kingdom)

Objectives:The study was planned to evaluate the efficacy and safety of Livwin (polyherbal formulation) in acute viral hepatitis.Materials...Full Text Available

UK PubMed Central (United Kingdom)

AIMSTo evaluate and compare the risk of specific safety outcomes in patients prescribed ibuprofen and paracetamol concomitantly with those in patients prescribed ibuprofen or paracetamol...Full Text Available

International Science & Technology Center (ISTC)

Thermodynamic Stable Metal Compositions for Improvement of an Operational Safety of Constructional Materials under Conditions of Multifactor Loadings of an Aggressive Environment

Energy Technology Data Exchange (ETDEWEB)

Short communication

Energy Technology Data Exchange (ETDEWEB)

Nuclear energy related research in Switzerland is concentrated at PSI's Nuclear Energy and Safety Research Department (NES). The activities of the department are concentrated on three main domains of: Safety and related problems of operating plants; safety features of future reactor and fuel cycles; waste management. Comprehensive assessments of energy systems are carried out in cooperation with PSI's General Energy Research Department. Many of the programs are part of collaborations with universities, industry, or international organisations. Progress in 2000 in these topical areas is described in this report. A list of scientific publications in 2000 is also provided.

British Library Electronic Table of Contents (United Kingdom)

This research investigates the impact of national culture and several institutional factors on the safety performance of society and establishes statistically significant relationships between those variables. As expected, the research results reveal that some cultural variables such as uncertainty avoidance, gender orientation and institutional variables such as the degree of law avoidance can directly influence the safety performance of the society. The findings also support the inverted u-curve (Safety Kuznet curve) hypothesis indicating even if we expect a negative trend at the beginning stage of industrialization, we can expect a positive trend in safety performance as their income level continues to improve beyond a certain point.

Science.gov (United States)

... These are abnormal and an indication of NAVAIRINST 13340.3 identifies these laboratories a possible breakdown in the fuel-handling equip- ...

Energy Technology Data Exchange (ETDEWEB)

The present research has been made to develop and review critically the functional requirements of the specific safety systems of CANDU such as SDS-1, SDS2, ECCS, and containment. Based on R documents for this, a systematic study was made to develop the domestic regulation statements. Also, the conventional laws are carefully reviewed to see the compatibility to CANDU. Also, the safety assessment method for CANDU was studied by reviewing C documents and recommendation of IAEA. Through the present works, the vague policy in the CANDU safety regulation is cleaning up in a systematic form and a new frame to measure the objective risk of nuclear power plants was developed.

CERN Document Server

Kelvin-Helmholtz instability of short gravity waves is examined in order to explain the recent findings of the decrease in momentum transfer from hurricane winds to sea waves. A three-fluid configuration of a foam layer between the atmosphere and the ocean is suggested to provide signifficant stabilization of the system and shifting the marginal critical wavelength to the shortwave part of the spectrum. It is conjectured that such stabilization leads to the observed drag reduction. The high contrasts in three fluid densities provide a universal mechanism for stabilizing surface perturbations.

International Nuclear Information System (INIS)

In the framework of the equivalence theorem the one-loop helicity amplitudes and cross section for the double Higgs production process #gamma##gamma##->#HH are calculated. It is shown that the cross section is measurable at TeV #gamma##gamma# colliders and is marginally sensitive to the triple-Higgs variation. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Late plagiogranite bodies in the Semail ophiolite have been previously suggested to represent late stage fractionates within an episodic spreading center magma chamber or the roots of seamount chains. Field and lab observations suggest that these late silicic magma chambers represent zones of repeated injection by dikes of intermediate to mafic composition. Multiple generations of intrusion, partial resorption and reintrusion are preserved in the plagiogranite as 1) relict phantom xenoliths, 2) angular xenoliths with quartz-rich margins, 3) deformed fine-grained dikes with distinct chilled margins, and 4) planes of rectangular blocks with cuspate margins or ellipsoids of similar fine grained mafic materials. The blocks and ellipsoids are actually dismembered mafic dikes that chilled by intruding a cooler silicic liquid and were either thermally fractured or pinched out. All of the dikes are hydrothermally altered to ...

International Nuclear Information System (INIS)

We reviewed retrospectively the magnetic resonance (MR) images of 14 soft-tissue lesions of fibromatosis (desmoid tumors) encountered in 11 patients. The lesions were typically inhomogeneous in texture and round to oval in configuration. Margins were well-defined in 78% of the lesions at presentation and were infiltrating in all recurrences. (orig./DG).

International Nuclear Information System (INIS)

Intrahepatic cholangiocarcinoma is an uncommon tumor as primary hepatic neoplasm. Five cases of cholangiocarcinoma, mass forming peripheral type, are reported about its CT findings. They were manifested as a poorly marginated low density mass with a irregular stellate area. In one case, a cut section of the gross specimen following surgery showed a central callagenous scar and vessels within the necrotic tumor. (author).

Energy Technology Data Exchange (ETDEWEB)

The effect of finite gyroradius on the current diffusive ballooning mode is examined. Starting from the reduced MHD equations including turbulent transports, coupling with drift motion and finite gyroradius effect of ions, we derive a ballooning mode equation with complex transport coefficients. The eigenfrequency, saturation level and thermal diffusivity are evaluated numerically from the marginal stability condition. Preliminary results of their parameter dependence is presented. (author)

International Nuclear Information System (INIS)

The rod drop time event of the Daya Bay Nuclear Power Plant is caused by the malfunction of the guide tube developed by Framatome. Three temporary solutions were implemented successively and the long term solution was found in the process of searching for the root cause. The different solutions and the root cause are introduced. The safety analysis and license of the solutions are mainly discussed. Experiences and lessons are drawn by summarizing the important items related to nuclear safety.

Energy Technology Data Exchange (ETDEWEB)

Public Law 95-209 includes a requirement that the Advisory Committee on Reactor Safeguards submit an annual report to Congress on the safety research program of the Nuclear Regulatory Commission. This report presents the results of the ACRS review and evaluation of the NRC safety research program for Fiscal Year 1982. The report contains a number of comments and recommendations.

International Nuclear Information System (INIS)

The requirements are given as placed on the development, procurement, maintenance, and application of software for the creation or processing of data during the design, construction, operation, repair, maintenance and safety-related upgrading of nuclear power plants. The verification and validation processes are highlighted, and the requirements put on the software documentation are outlined. The general quality assurance principles applied to safety analyses are characterized. (J.B.). 1 ref.

Science.gov (United States)

This report is designed to cover the overall Operation Castle radiological safety matters from the viewpoint of those issues of direct concern to Headquarters, Joint Task Force Seven. It was written for the express purpose of assisting in the development of future radiological safety plans by presenting detailed discussion of the problems and solutions arising during Operation Castle. Included is a discussion of fallout forecasting techniques.

Energy Technology Data Exchange (ETDEWEB)

The 200 Area Interim Storage Area Technical Safety Requirements define administrative controls and design features required to ensure safe operation during receipt and storage of canisters containing spent nuclear fuel. This document is based on the 200 Area Interim Storage Area, Annex D, Final Safety Analysis Report which contains information specific to the 200 Area Interim Storage Area.

Science.gov (United States)

... Lincoln Laboratory Distribution Models for Optical Scintillation Due to Atmospheric Turbulence RR Parenti RJ Susiela Group 107 ...

International Nuclear Information System (INIS)

Supplemental criticality safety analysis of a pool type storage for TRIGA spent fuel at 'Jozef Stefan' Institute in Ljubljana, Slovenia, is presented. Previous results (Ravnik, M, Glumac, B., 1996) have shown that subcriticality is not guaranteed for some postulated accidents. To mitigate this deficiency, a study was made about replacing a certain number of fuel elements in the rack with absorber rods (Glumac, B., Ravnik, M., Logar, M., 1997) to lower the supercriticality probability, when the pitch is decreased to contact (as a consequence of a severe earthquake) in a square arrangement. The criticality analysis for the hexagonal contact pitch is presented in this paper, following the same scenario as outlined above. The Monte Carlo computer code MCNP4B with ENDF-B/VI library and detailed three dimensional geometry was used. First, the analysis about the influence of the number of triangular fuel piles on the bottom that could appear, if the fuel rack, made of ...

Energy Technology Data Exchange (ETDEWEB)

Among the items of the Sunshine Project in fiscal 1981 for development of a solvent extraction and liquefaction plant, this paper describes the achievements in developing secondary hydrogenation. A small continuous hydrogenation device equipped with three reaction columns that can be filled with catalyst of 50 cc, and a dedicated testing room were designed, and orders were placed with manufacturers. The fabrication, assembly, delivery, installation, piping and wiring were all completed. The device passed a completion inspection based on the high-pressure gas safety assurance law in December 1981. After leakage due to gas and material oil was checked, a trial operation was performed, and verified of normal operation. A screening test was carried out on three kinds of commercially available and prototype catalysts before testing the SRC containing material for studying the secondary hydrogenation. The circulating solvent having a boiling point ...

International Nuclear Information System (INIS)

Developed under the PN II Project 71-009 - MONA, the pre-operational monitoring program of the LIL waste disposal site presented in this paper covers the main elements requested for a continuous improvement of site characterization and safety assessment, as well as for the set up of the baseline data requested for the future operational and post-operational monitoring and surveillance. These elements are: vadose and saturated zones hydrogeology, surface erosion, meteorology and radionuclides content in waters, soil and biota. Pairs of TDR (Time Domain Reflectometry) and pressure sensors, coupled with a meteorological station have been installed on site for the continuously measurement of the water content and matric potential changes due to the climate variations. The data will be used to follow the water balance, the pores water velocity and to calculate the infiltration rate. A new set of erosion rates experimentally determined by Pinhole ...

International Nuclear Information System (INIS)

The commercial Modular High Temperature Gas-Cooled Reactor (MHTGR) achieves improved reactor safety performance and reliability by utilizing an integrated sequence of completely passive thermal storage and heat transfer mechanisms to reject decay heat in the event that all its active cooling systems fail to operate. During such events, the initial heatup transient in the core is followed by a quasi-steady state cooldown process which, if uninterrupted, can continue for several days. A buoyancy-driven natural convection cooling system called the RCCS facilitates the continuous heat removal by circulating ambient air through the reactor cavity, where it is heated and then exhausted to the outside environment. The peak thermal load on the RCCS occurs approximately at the time that the vessel reaches its highest temperature. To confirm the adequacy of the RCCS design, detailed analytical models were developed to simulate the decay heat removal process and predict the ...

International Nuclear Information System (INIS)

The sixth AER benchmark is the second AER benchmark for couplings of the thermal hydraulic codes and three dimensional neutron kinetic core models. It concerns a double end break of one main steam line in a WWER-440 plant. The core is at the end of its first cycle in full power conditions. In VTT HEXTRAN2.9 is used for the core kinetics and dynamics and SMABRE4.8 as a thermal hydraulic model for the primary and secondary loop. The plant model for SMABRE consists mainly of two input models, Loviisa model and a standard WWER-440/213 plant model. The primary loop includes six separate loops, the pressure vessel is divided into six parallel channels in SMABRE and the whole core calculation is performed in the core with HEXTRAN. The horizontal steam generators are modelled with heat transfer tubes in five levels and vertically with two parts, riser and downcomer. With this kind of detailed modelling of steam generators there occurs strong flashing after break opening. As a sequence of the ...

Energy Technology Data Exchange (ETDEWEB)

The secondary side corrosion of steam generator tubes is the main degradation of components in operating power plants, strongly impacted by chemistry. This is why EDF has largely studied the chemical parameters in its 56 PWRs which might influence corrosion development. The results of 168 hideout returns of chemical species performed on the French plants allowed to draw conclusions on where chemical species are likely to concentrate in steam generators and on the influence of several contaminants on corrosion processes: sodium, chloride, phosphate, organic compounds, etc... Based on laboratory studies and plants feedback, new chemistry specifications were established and are now applied to EDF units to minimize corrosion and operating costs and to provide a good availability while maintaining an excellent safety. Boric acid is added in the secondary water of the 10 oldest units with Inconel 600 MA tubing, highly sensitive to intergranular stress corrosion cracking. ...

Energy Technology Data Exchange (ETDEWEB)

Several steam generator tube rupture accidents have occurred at plants in the past. In this paper the Computational Multi-Fluid Dynamics (CMFD) investigation of the horizontal steam generator thermal-hydraulics during the tube rupture accident is performed. A guillotine of a steam generator U-tube is assumed with choked flow from the primary to the secondary side of the steam generator. We have computed water and steam velocity fields, steam volume fraction distribution on the steam generator secondary (shell) side, as well as the swell level increase. The simulation results are a support to the safety analyses of the steam generator tube rupture accident. Numerical simulation is performed with the multidimensional multi-fluid modelling approach. The two-phase flow around steam generator tubes in the bundle is modelled by the porous media approach. Interfacial mass, momentum and energy transfer are modelled with the closure laws. The governing equations are solved ...

International Nuclear Information System (INIS)

Liquid sodium is used as coolant in Fast Breeder Reactors (FBR). There is a likelyhood of sodium spillage in ambient air in the Steam Generator Building (SGB) of the FBR plant. Due to high chemical reactivity with oxygen, especially at temperatures greater than 573 K, it catches fire very easily. In order to carryout safety related experimental studies for different modes of sodium fires and to develop suitable mathematical models for the assessment of their consequences, an experimental facility (SFEF, Sodium Fire Experimental Facility) is being setup a IGCAR, Kalpakkam. The SFEF is having a 540 m"3 volume experimental hall. Stainless steel linear will be provided on the inside surfaces of experimental hall walls, ceiling and floor. Analysis has been carried out for enclosed sodium pool fire scenarios in SFEF by using sodium pool fire code SOFIRE II, which estimates the thermal transients like pressure rise, gas temperature rise, cell wall ...

Energy Technology Data Exchange (ETDEWEB)

In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of ...

Science.gov (United States)

Dr. Rudolf Schulten of West Germany and expert witnesses from national laboratories, utilities, and the nuclear industry testified on reactor safety issues as they relate to the Chernobyl accident and public concern that modern technology has not paid enough attention to public safety. Each of the witnesses contributed safety-related information based on what has been learned from the Soviet incident. Particular focus went to similarities and differences between the Chernobyl and US reactors in safety design and engineering and to the environmental effects of the accident. The N reactor near Richland and a commercial reactor at Fort St. Vrain, Colorado are the only two operating graphite reactors, but neither is a boiling water reactor.

Energy Technology Data Exchange (ETDEWEB)

Implementation of Title 10 Code of Federal Regulations Part 830, Subpart B Nuclear Safety Management (1) was accomplished at the Waste Isolation Pilot Plant (WIPP) in a timely and efficient manner. The primary reason the transition went smoothly was that the existing safety analysis was relatively new, initially developed in 1995, and written in accordance with the safe harbor document DOE-STD-3009 (2). The WIPP Safety Analysis Report (SAR) (3) is kept up-to-date with the unreviewed safety question (USQ) process and thorough oversight and input provided by DOE-Carlsbad Field Office (CBFO) documented in the annual safety evaluation report (SER) process.

International Nuclear Information System (INIS)

Internationally, on-line maintenance (OLM) of nuclear power plants under the operation is prevailed to enhance nuclear safety and economics. In recent years, Korea Hydro and Nuclear Power Co. Ltd. (KHNP) is eager to apply OLM. Ministry of Education, Science and Technology (MEST) has established the related technology development program as an item of 'Overall Planning on Nuclear Safety(2010-2014)' through acceptance to the request of KHNP in 2009. OLM is defined as maintenance that is performed with the main generator connected to the grid. In other words, it means a preventive maintenance to be implemented during the allowable outage time (AOT) with ignoring inoperability of safety-related equipment listed in the technical specifications. The Korea Institute of Nuclear Safety (KINS) is developing the assessment technology of safety concerns for OLM under the auspices of MEST. Draft ...

International Nuclear Information System (INIS)

The paper discusses the safety problems connected with the conversion to dense storage of RBMK-1000 spent fuel in reactor cooling pools and independent storage facilities. Recourse to dense storage has been made for a number of reasons, among which are the absence of spent fuel shipments from the nuclear power plant site, prolongation of storage time and a partial change in storage conditions. Increasing the storage density per unit volume of the storage facility and turning to new technical procedures (as against the basic design) call for further investigation of safety problems. The safety assessment of the dense storage mode includes: (1) Selecting a list of initiating events for design basis and unforeseeable accidents; (2) Assessing dense storage safety under normal as well as design basis accident conditions; (3) Safety analysis and development of measures to compensate for ...

International Nuclear Information System (INIS)

The UK fully supports the objective of the Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management to achieve and maintain a high level of safety worldwide in spent fuel and radioactive waste management, through the enhancement of national measures and international co-operation, including where appropriate, safety-related co-operation. The UK's Health and Safety Executive, through its Nuclear Safety Directorate (NSD), has been committed to the Convention since the initial negotiations to set up the Convention and provided the president of the first review meeting in 2003. It would be wrong of any nation to believe that they have all the best solutions to managing spent fuel and radioactive waste. The process of compiling reports for the Convention review meetings provides a structured process through which every ...

International Nuclear Information System (INIS)

The operation and safety of both fossil-fuel and nuclear power stations depend on adequate cooling of the thermal source involved. This is usually accomplished using liquid coolants that are forced through the high temperature regions by a pumping system; this fluid then transports the thermal energy to another section of the power station. However, fluids that undergo boiling during this process create vapor that can be detrimental, and influence safe operation of other system components. The behavior of this vapor, or void, as it is generated and transported through the system is critical in predicting the operational and safety performance. This study uses two advanced penetrating radiation techniques, Real Time Neutron Radiography (RTNR), and High Speed X-Ray Tomography (HS-XCT), to examine void generation and transport behavior in a flow boiling system. The geometries studied were tube side flow boiling in a cylindrical configuration, and ...

Energy Technology Data Exchange (ETDEWEB)

This report describes the state of the art of electric energy storage technologies and discusses how adding intermittent renewable energy technologies (IRETs) to a utility network affects the benefits from storage dispatch. Load leveling was the mode of storage dispatch examined in the study. However, the report recommended that other modes be examined in the future for kilowatt and kilowatt-hour optimization of storage. The motivation to install storage with IRET generation can arise from two considerations: reliability and enhancement of the value of energy. Because adding storage increases cost, reliability-related storage is attractive only if the accruing benefits exceed the cost of storage installation. The study revealed that the operation of storage should not be guided by the output of the IRET but rather by system marginal costs. Consequently, in planning studies to quantify benefits, storage should not be considered as an entity belonging to the system ...

Energy Technology Data Exchange (ETDEWEB)

The use of excitation system controls, specifically the Power System Stabilizer (PSS), to improve damping of power system oscillations and thus extend steady-state stability limits has been a subject of great interest in recent years. The desire to more fully utilize transmission capacity led to the installation of PSS controls on greater numbers of generating units to maintain stability margins. This paper addresses the tuning and adjustment of PSS controls in a two unit power plant. Both analytical studies and field test confirmations are presented. The practical difficulties of verifying the PSS control loop gain margin by testing are explored. A simplified procedure is outlined. The Lower Colorado River Authority (LCRA), Fayette Power Project (FPP) consists of two 683.7 MVA tandem compound steam turbine driven generators. The excitation systems are of the alternator rectifier type and the PSS control utilizes shaft speed as an input signal. ...

Energy Technology Data Exchange (ETDEWEB)

Sequence stratigraphic interpretation of paralic successions is complicated by the complex interfingering of marine and continental strata. The successions may also include terrestrial extensions of marine parasequences and completely independent lacustrine parasequence analogues. Failure in recognizing the possible interbedding of these two independent parasequence types may lead to construction of sequence stratigraphic schemes based on incompatible data sets. We have studied a Lower Jurassic paralic section from the Baltic island of Bornholm. The Hettangian-Sinemurian Sose Bugt Member (Ronne Formation) of Bornholm includes lacustrine, fluvial and restricted marine, estuarine deposits reflecting the basin-margin position. Biostatigraphic resolution is poor and a sequence stratigraphic interpretation of the paralic succession is far from straightforward. A multidisciplinary approach including facies analysis, recognition and lateral tracting of key surface, ...

Energy Technology Data Exchange (ETDEWEB)

Forty-one cases of mediastinal tumor examined by computed tomography were reviewed. CT findings of the mediastinal malignancy were as follows: 1) inhomogeneous density on contrast CT, 2) equivocaton of fat plane surrounding the tumor, 3) irregular margin. Benign teratoma had smooth margin and included fat or calcification density. Mediastinal seminoma was observed as a lobulated mass with no calcification on CT. These findings were similar to the patterns of malignant thymoma or lymphoma. Consequently, it was very difficult to differentiate between malignant thymoma and malignant lymphoma by CT. According to our data, malignant thymoma tended to expand to only one side of the anterior mediastinum and to invade the anterior chest wall. On the other hand, malignant lymphoma of anterior medistinal type expanded into the trachea and the superior vena cava. In patients with sarcoidosis, the enlargement of bilateral hilar lymph nodes was commonly ...

British Library Electronic Table of Contents (United Kingdom)

The online communicative environment is expected to revolutionize political discourse as it expands to cover underrepresented groups and ideas. In this platform, marginalized groups such as indigenous communities from the developing world can articulate claims, strategically mobilize and participate in the forms of meaning-making that constitute them. However, there is skepticism on the actual value of online spaces in effecting agency in an internet-mediated environment. Using James Scott's notion of 'hidden transcripts' and Andrew Feenberg's 'democratic rationalization of technology', the paper explores strategic approaches and historical, social, and political conditions embedded in the construction, negotiation, and transformation of indigenous online activist media. In-depth interview...

International Nuclear Information System (INIS)

This paper summarises the main results obtained so far in the frame of the EU Home Team test programme of ITER primary wall small scale mock ups. It describes briefly the fabrication method of the mock ups, the test conditions and the main results obtained with high heat flux and thermal fatigue tests of Cu alloy/stainless steel and beryllium/Cu alloy/stainless steel mock ups. The results obtained so far show good thermal fatigue performance and operation margin of the ITER primary first wall concept. (author)

International Nuclear Information System (INIS)

We analyse in detail the SL(2, R) black hole by extending standard techniques of Kac-Moody current algebra to the non-compact case. We construct the elements of the ground ring and exhibit W_#infinity# type structure in the fusion algebra of the discrete states. As a consequence, we can identify some of the exactly marginal deformations of the black hole. We show that these deformations alter not only the spacetime metric but also turn on non-trivial backgrounds for the tachyon and all of the massive modes of the string. (orig.).

Energy Technology Data Exchange (ETDEWEB)

CERN has encouraged the US-LARP collaboration to participate in Phase I of the LHC luminosity upgrade by analyzing the benefits gained by using Nb3Sn technology to replace the functionality of select NbTi magnets that CERN is committed to construct. Early studies have shown that the much higher gradients (shorter magnetic lengths) and temperature margins (quench stability) of Nb3Sn magnets compared to their NbTi counterparts is favorable--allowing the insertion of additional absorbers between Q1 and Q2, for example. This paper discusses the relative merits of the NbTi and Nb3Sn options.

International Nuclear Information System (INIS)

The prevailing hypothesis of linear extrapolation from high to low radiation doses without any threshold level is being questioned more and more strongly for radiobiological and epidemiological reasons and, consequently, also on socio-economic and ethical grounds. A cost-benefit analysis based on scientific facts and made plausible to the general public, concentrating on a comparison with demonstrable natural and manmade risks, most probably would result not only in the permissible limits being raised by a considerable margin, but also in billions of costs saved, and in greater acceptance of all peaceful uses of radiation, nuclear power included. (orig.)

Environmental Research Database

ObjectivesNot EnteredDescriptionMethane hydrate in an ice-like substance consisting of molecules of methane gas combined chemically with water. It is stable at high pressures and low temperatures. Since the ocean floor is normally cold, but temperatures increase with depth inside the Earth, such conditions normally prevail for a few hundred meters below the seafloor where the ocean depth is more than a few hundred metres. Methane beneath the ocean floor is formed by the decomposition of organic material. At the edges of the co [continued...