Energy Technology Data Exchange (ETDEWEB)

Isothermal reaction experiments were performed in the temperature range of 1000 - 1300 C in order to determine the chemical interactions between Zircaloy-4 fuel rod cladding and Inconel-718 spacer grids of Pressurized Water Reactors (PWR) under severe accident conditions. It was not possible to apply even higher temperatures since fast and complete liquefaction of the components occurred as a result of eutectic interactions during heatup. The liquid reaction products formed enhance and accelerate the degradation of the material couples and the fuel elements, respectively. Only small amounts of Inconel are necessary to liquefy large amounts of Zircaloy. Thin oxide layers on the Zircaloy surface delay the beginning of the chemical interactions with Inconel but cannot prevent them. In this work the reaction kinetics have been determined for the system: as-received and pre-oxidized Zircaloy-4/Inconel 718. The interactions can be described by parabolic rate laws; the ...

ScienceCinema

...of this article he quotes um i am told by my english ...

Energy Technology Data Exchange (ETDEWEB)

Short communication

Energy Technology Data Exchange (ETDEWEB)

Based on the enhanced cooperation between Republic of Korea (ROK) and International Atomic Energy Agency (IAEA), IAEA installed new safeguards equipment (Unattended Monitoring System, UMS) at Wolsung unit 2 on January, 2005. The UMS was utilized in parallel with traditional human surveillance during the transfer campaign of Wolsung unit 2 (7 March - 22 July). Installation of UMS at all Wolsung units will be decided on the basis of the result of this test. The transfer campaign with UMS at Wolsung units 2 and 4 was started from September 1, 2006 at the same time. Implementation of UMS to the transfer campaign in Wolsung site will be considerably reduced the IAEA's inspection effort and burden of operator.

International Nuclear Information System (INIS)

... bwr type reactors closures fluidic control devices operation performance pwr

Energy Technology Data Exchange (ETDEWEB)

Mitsubishi is now developing a new Pressurized water reactor (PWR), the Mitsubishi simplified PWR (MS-PWR), which has the innovative features of hybrid safety systems (an optimum combination of passive and active systems) and cooling by horizontal steam generators. In order to confirm the feasibility of the Mitsubishi hybrid safety system, various kinds of safety analyses are performed for loss-of-coolant accident events. In parallel to these safety analysis efforts, the following thermal-hydraulic tests are to be performed: (1) thermal-hydraulic test of a horizontal steam generator; (2) integrated thermal-hydraulic test using a simulation loop for the innovative MS-PWR (SLIM).

Science.gov (United States)

... 041.034.0403 The Morphological Basis of the Armor-Like Folded Skin of the Greater Indian Rhinoceros ... hendo@um.u-tokyo.ac.jp ...

Science.gov (United States)

Imaging of NGC 7469 in the J, H, & K bands shows that the starburst 'ring' is a tight inner

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

... Japan) Kobayashi, Minoru AITEL Corp., Yokohama, Kanagawa (Japan)

CERN Document Server

Canary Islands are normally interested by dominant North-East winds that, in some meteorological conditions, can transport sand at high altitude from the Sahara desert. The dust may affect the efficiency of the telescopes and decreases the transparency of the sky. In order to maximize the scientific return of the telescopes located at the ORM, we present an analysis of the atmospheric dust content and its effects on astronomical observations. B, V and I dust aerosol astronomical extinction are derived. Using a 5 years series database of data taken from the four channel TNG dust monitor, we compute a mean hourly and daily values of the dust content. We have detected particles having size 0.3, 0.5, 1.0 and 5.0 um. Using a power law we have derived the content of 10.0 um particles. We found a typical local dust concentration ranging from 3x10^6 particles per cubic meter at 0.3 um, to 10^3 at 5.0 um and 10 ...

CERN Document Server

We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities > 100 mJy at 500 um, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems in Spitzer IRAC 3.6 and 4.5 um data and successfully disentangle the foreground lens from the background source in each case, providing important constraints on the spectral energy distributions (SEDs) of the background SMG at rest-frame optical-near-infrared wavelengths. The SED fits show that these two SMGs have high dust obscuration with Av ~4 to 5 and star formation rates of ~100 M_sun/yr. They have low gas fractions and low dynamical masses compared to 850 um selected galaxies.

International Nuclear Information System (INIS)

A method to reduce the fuel composition heterogeneity effect on the core performance parameters has been studied for the DUPIC fuel which is made of spent pressurized water reactor (PWR) fuels by a dry refabrication process. This study focuses on the reactivity control method which uses either slightly enriched, depleted, or natural uranium to minimize the cost rise effect on the manufacturing of DUPIC fuel, when adjusting the excess reactivity control by slightly enriched and depleted uranium, reactivity control by natural uranium for high reactivity spent PWR fuels, and reactivity control by natural uranium for linear reactivity spent PWR fuels. The results of this study have shown that the reactivity control by slightly enriched and depleted uranium, all the spent PWR fuels can be utilized as the DUPIC fuel and the fraction of fresh uranium feed is 3.4% on an average. For the reactivity control by ...

International Nuclear Information System (INIS)

... Sergio Department of Materials, University of Oxford, Oxford (United Kingdom)

Energy Technology Data Exchange (ETDEWEB)

It was agreed that both of the Republic Of Korea (ROK) and the International Atomic Energy Agency (IAEA) cooperate with the new approach using the Unattended Monitoring Systems (UMS), the mailbox declaration and the short notice inspections, which can decrease the agency inspection efforts and operator' s burden. As a result of the positive cooperation of ROK for applying new approach, the IAEA could accomplish a successful implementation of new safeguards approach during last transfer campaigns at Wolsung site. As of the end of Feb. 2007, the IAEA installed the UMS at Wolsung units 2, 3 and 4. The transfer campaigns at Wolsung units 2 and 4 are performing from April, 2007. The IAEA will install the UMS at Wolsung unit 1 by the end of 2007. Then agency will inspect all of transfer campaign at Wolsung units by using new approach with UMS, mailbox declaration and SNI. It is based on the SSAC full ...

Energy Technology Data Exchange (ETDEWEB)

Short communication.

Science.gov (United States)

... by Remote Setting., Maryland Sea Grant Extension Program. Oyster aquaculture workbook series. Publication UM-SG-MAP-95-03. ... ...

CERN Document Server

Preliminary experiments have been performed to investigate the effects of radiative cooling on plasma jets. Thin (3 um - 5 um) conical shells were irradiated with an intense laser, driving jets with velocities > 100 km/s. Through use of different target materials - aluminium, copper and gold - the degree of radiative losses was altered, and their importance for jet collimation investigated. A number of temporally resoved optical diagnostics was used, providing information about the jet evolution. Gold jets were seen to be narrower than those from copper targets, while aluminium targets produced the least collimated flows.

Energy Technology Data Exchange (ETDEWEB)

Since first PWR in Japan started commercial operation in 1970, we have encountered the various modes of corrosion on primary and secondary side components. We have paid much efforts for resolving these corrosion problems, that is, investigating the causes of corrosion and establishing the countermeasures for these corrosion. We summarize these efforts in this article. (author)

Energy Technology Data Exchange (ETDEWEB)

A series of pipe rupture tests has been performed at JAERI to demonstrate the safety of primary coolant circuits in the event of pipe rupture in nuclear power plants. Pipe whip tests and jet discharge tests have been conducted under BWR and PWR loss-of-coolant accident (LOCA) conditions. The present paper describes the experimental and analytical results of the pipe whip tests performed under PWR LOCA conditions using 4, 6 and 8-inch test pipes. The tests were carried out at an initial pressure and temperature of 15.7 MPa and 325/sup 0/C, respectively. Moreover, a dynamic analysis of pipe whip tests was carried out using the general purpose finite element programm ADINA.

Energy Technology Data Exchange (ETDEWEB)

A thermohydraulic study of MTR fuel element is presented as a basic requirement for the development of an irradiation facility for testing fuel elements. A computer code named 'Thermo' has been developed for this purpose, which can stimulate different working conditions, such as, cooling, power elements and neutron flux, performing all pertinent thermohydraulic calculations. Thermocouples were used to measure the temperature gradients of the cooling fluid throughout the IEAR-1 reactor core. All experimental data are in good agreement with the theoretical model applied in this work. Finally, a draft of the proposed facility and its safety system is presented. (author)

Energy Technology Data Exchange (ETDEWEB)

The contribution attempts a definition of the concepts of ``technical facilities`` and ``facility management``. [Deutsch] Um mit der Ueberschrift zu beginnen: Was ist Gebaeudetechnik? Die Antwort ist nicht ganz einfach. An der TU Berlin gibt es einen Ingenieur-Studiengang mit dieser Bezeichnung. Es hat etwas mit dem Gebaeude, aber nicht viel mit Architektur zu tun, wie manchmal faelschlich angenommen wird. Um solche Missverstaendnisse gar nicht erst aufkommen zu lassen, hat sich die Gruppe des Vereins Deutscher Ingenieure, die sich mit der Gebaeudetechnik beschaeftigt, als `VDI-Gesellschaft Technische Gebaeudeausruestung` bezeichnet. (orig.)

International Nuclear Information System (INIS)

The installation procedure, the fabrication, fitting up, positioning, adjustment and welding of piping, examinations, hydrostatics testing and insulation of piping for reactor primary circuit piping of Daya Bay Nuclear power Plant are briefly described.

Energy Technology Data Exchange (ETDEWEB)

Comments are made on the Public Inquiry into CEGB's proposal to construct a pressurized water reactor (PWR) at Sizewell, UK. Aspects discussed include: time elapsed and its possible effect on the result; economics of nuclear power plants compared with coal-fired power plants; changes in real sterling/dollar exchange rates; effect of mineworkers' strike; the UK electric power generating system; AGR reactors compared with PWR reactors; extension of Magnox reactor life; radioactive waste management; political decisions.

International Nuclear Information System (INIS)

Since the PWR plants in Japan have been operated more than 30 years, main instrumentation control equipment of analog systems has been renewed to digital control systems. Renewal works had to be done in short period within periodical inspection term and for several facilities. The Mitsubishi LTD group had been provided with these market needs by its digital control system (MELTAC-NplusR 3) applicable to main instrumentation control equipment for primary and secondary systems and had already finished the renewal for practical plants. (T. Tanaka)

Energy Technology Data Exchange (ETDEWEB)

Resistance of ALLOY 800 as a PWR/SG tubings to IGC/IGSCC and Ni, Co release into high temperature water was evaluated as compared with ALLOYs 600 and 690. The study to improve the resistance to IGSCC and general corrosion was also made. From the results, ALLOY 800 was evaluated to be the most reliable among the high Ni alloys tested. In addition, the alloy would obtain further reliability in IGSCC and general corrosion resistance by the combined addition of Ti and Nb, and the prior oxidation treatments, respectively. (author).

International Nuclear Information System (INIS)

The thermal-hydraulic tests for a horizontal steam generator of a next-generation PWR (New PWR-21) were performed. The purpose of these tests is to understand the thermal-hydraulic behavior in the secondary side of horizontal steam generator during the plant normal operation. A test was carried out with cross section slice model simulated the straight tube region. In this paper, the results of the test is reported, and the effect of the horizontal steam generator internals on the thermal-hydraulic behavior of the secondary side and the circulation characteristics of the secondary side are discussed. (author).

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

In-core thermal-hydraulics during a PWR reflood phase following a large-break LOCA are quite unique in comparison with two-phase flow which has been studied widely in previous researches, because the geometry of the flow path is complicated (bundle geometry) and water is at extremely low superficial velocity and almost under stagnant condition. Hence, some phenomena realized during a PWR reflood phase are not understood enough and appropriate analytical models have not been developed, although they are important in a viewpoint of reactor safety evaluation. Therefore, author investigated some phenomena specified as important issues for quantitative prediction, i.e. (1) void fraction in a bundle during a PWR reflood phase, (2) effect of radial core power profile on reflood behavior, (3) effect of combined emergency core coolant injection on reflood behavior, and (4) the core separation into two thermal-hydraulically different ...

Energy Technology Data Exchange (ETDEWEB)

The analytical results of blowdown characteristics and its thrust force were compared with the experiment, which were performed as pipe whip tests under the PWR LOCA conditions on the hypothetical accident of guillotine break of pipes. The blowdown thrust force was obtained by the integral momentum equation about single-phase flow, homogeneous and separated two-phase flow, assuming critical pressure at the exit if critical flow condition was satisfied. The following results are obtained: (1) The node-junction method is useful for the analysis of water hammer phenomena and of the blowdown thrust force. (2) The Henry-Fauske model for subcooled critical flow is effective for the analysis of the maximum thrust force under the PWR LOCA conditions. The jet thrust parameter of analysis and experiment is 1.08. (3) The thrust parameter of saturated blowdown has the same one with the value under pressurized condition when the stagnant pressure is chosen ...

Energy Technology Data Exchange (ETDEWEB)

The multidimensional countercurrent two-phase flow regimes that occur in a pressurized-water reactor (PWR) vessel downcomer during the refill phase of a large-break loss-of-coolant accident are studied using a transparent 1/10 scale model of a PWR vessel. The various flow regimes and their distribution in the downcomer have been identified and mapped for a range of air-water flooding experiments. The two-phase flow patterns that are identified in the downcomer included various types of film flows, droplet flows, countercurrent churn flows and cocurrent flows depending on the flooding condition. Through observation of the two-phase flow dynamics it was deduced that the physical mechanisms associated with the flooding processes could be separated into a liquid entrainment process and a film flow reversal process. In addition to the above exercise, the effect of non-uniform injection of water into the downcomer via different combinations of cold ...

Energy Technology Data Exchange (ETDEWEB)

The research and development for the first year of the project are performed through specialization of researchers, information from aborad and international cooperation, securement of advanced nuclear technology, development and installation of test equipment, application of external man-power, establishment of advanced test techniques, and certified test method. 1. Absolute efficiency measurement examination technology development of gamma scanning system 2. Sample preparation technology development of SEM and EPMA for micro-structural observation and chemical composition analysis 3. Irradiated high burn-up nuclear fuel transportation and test for PWR 4. Development of hot cell examination techniques and equipment 5. Acquirement of KOLAS system. In addition to the project, the following activities are carried out as follows; - PIE of Hanaro fuel(KH99H-001) - PIE of U-Mo advanced nuclear fuel irradiated at Hanaro - PIE of Hi-MET advanced nuclear fuel irradiated at ...

Energy Technology Data Exchange (ETDEWEB)

A algorithm was developed to determine the characteristic parameters of PWR spent fuel, such as burnup, cooling time and initial enrichment of {sup 235}U by use of gamma-ray activity ratios of {sup 134}Cs/{sup 137}Cs, {sup 154}Eu/{sup 137}Cs and {sup 106}Ru/{sup 137}Cs from the high resolution gamma-ray spectroscopy and ORIGEN-S calculations. For the verification of the method developed, gamma-ray measurements of Kori-1 and Kori-2 nuclear fuel rods were carried out using HPGe gamma ray scanning system. As a results, it is revealed that the measured values are in a good agreement with the operator declared values within the about {+-} 5% errors. Besides, the under-water burnup measuring device has been designed to measure the gamma-ray from the PWR spent fuel assembly. This device will be set up in the pool of Post-Irradiation Examination Facility(PIEF), and used in determination of the average burnup, cooling time and initial enrichment of the ...

International Nuclear Information System (INIS)

Flow Accelerated Corrosion (FAC) of Carbon Steel (CS) piping has been one of main issues in Light-Water Nuclear Reactor (LWRs). Wall thinning of CS piping due to FAC increases potential risk of pipe rupture and cost for inspection and replacement of damaged pipes. In particular, corrosion products generated by FAC of CS piping brought steam generator (SG) tube corrosion and degradation of thermal performance, when it intruded and accumulated in secondary side of PWR. To preserve SG integrity by suppressing the corrosion of CS, High-AVT chemistry (Feedwater pH9.8#+-#0.2) has been adopted to Tsuruga-2 (1160 MWe PWR, commercial operation in 1987) in July 2005 instead of conventional Low-AVT chemistry (Feedwater pH 9.3). By the High-AVT adoption, the accumulation rate of iron in SG was reduced to one-quarter of that under conventional Low-AVT. As a result, a tendency to degradation of the SG thermal efficiency was improved. On the other hand, it ...

International Nuclear Information System (INIS)

The Surry low power and shutdown probabilistic risk analysis (PRA) is an ongoing project at Brookhaven National Laboratory (BNL) to identify and quantify potential accident scenarios that may occur in a pressurized water reactor (PWR) during low power and shutdown. It was initiated as a result of various incidents and accidents that have occurred within the United States and overseas. The project involves review and evaluation of PWR experience at shutdown, identification of accident scenarios, determination of methods to mitigate the accidents, and performance a level 1 PRA. An evaluation of accident progression, source terms and consequences has also been initiated. The results will be used to address issues related to shutdown conditions. The objective of this paper is to provide a progress report on the project, and to present the approach used as well as the preliminary results of the ongoing and completed tasks.

Energy Technology Data Exchange (ETDEWEB)

This study report presents the shutdown chemistry of PWR primary system to reduce and remove the radioactive corrosion products which were deposited on the nuclear fuel rods surface and the outside of core like steam generator channel head, RCS pipings etc. The major research results are the follows ; the deposition radioactive mechanism of corrosion products, the radiochemical composition, the condition of coolant chemistry to promote the dissolution of radioactive cobalt and nickel ferrite, the control method of dissolved hydrogen concentration in the coolant by the mechanical and chemical methods. The another part of study is to investigate the removal characteristics of corrosion product ions and particles by the demineralization system to suggest the method which the system could be operate effectively in shut-down purification period. (author). 19 refs., 25 figs., 48 tabs.

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).

International Nuclear Information System (INIS)

The research committee of the Atomic Energy Society of Japan on water chemistry standard aims at establishing the private standard of water chemistry of nuclear power plants. The committee gathers up 'BWR water chemistry management manual', 'PWR primary system water chemistry management manual' and 'PWR water chemical analysis standard method', and furthermore aims at the standardization of those in future. Looking back on the committee's activities for the past four years, latest results of research of water chemistry mainly contributing to safe and reliable nuclear power plants were described with the future perspective of water chemistry and a demanded break-through. (T.T.)

Energy Technology Data Exchange (ETDEWEB)

Resistance of Alloy 800 as a PWR S/G tube material to IGC/IGSCC and Ni, Co release into water was evaluated as compared with Alloys 600 and 690. The study to improve the resistance to IGSCC and general corrosion was also made, including the effects of shot-peening on the distribution of the residual stress of the U-bent tubes and the susceptibility to SCC, the stabilizing elements on IGC/IGSCC, and prior oxidation on general corrosion. From the results, shot-peened Alloy 800 was estimated to be the most reliable S/G tube material among the high nickel alloys tested. In addition, the Alloy 800 tube would obtain further reliability in IGSCC and general corrosion resistance by the combined addition of Ti, and Nb, and the prior oxidation of the inner tube surface, respectively.

Energy Technology Data Exchange (ETDEWEB)

This paper presents experimental and analytical results of pipe whip tests performed under PWR LOCA conditions using a test pipe of 4-inch diameter and U-shaped restraints. In the tests, the effects of the overhang length on the pipe whip behavior of the piperestraints system were studied by measuring the strains and deformations of the test pipe and restraints, and the restraints forces. The equation for predicting the maximum strain at the outer surface of the pipe was derived using a static equilibrium condition. The calculated maximum strains at the outer surface of the pipe agree fairly well with experimental data. The dynamic response analysis of the pipe-restraints system was conducted by the finite element program ADINA. The applicability of the ADINA program to the pipe whip analysis is made clear through this analysis.

Energy Technology Data Exchange (ETDEWEB)

With the issuance of the Decommissioning Rule (July 27, 1988), nuclear power plant licensees are required to submit to the US Regulatory Commission (NRC) for review, decommissioning plans and cost estimates. This user`s manual and the accompanying Cost Estimating Computer Program (CECP) software provide a cost-calculating methodology to the NRC staff that will assist them in assessing the adequacy of the licensee submittals. The CECP, designed to be used on a personnel computer, provides estimates for the cost of decommissioning PWR plant stations to the point of license termination. Such cost estimates include component, piping, and equipment removal costs; packaging costs; decontamination costs; transportation costs; burial costs; and manpower costs. In addition to costs, the CECP also calculates burial volumes, person-hours, crew-hours, and exposure person-hours associated with decommissioning.

Energy Technology Data Exchange (ETDEWEB)

In the framework of the plutonium production optimization in the PWR, many solutions are studied to decrease or recycle the plutonium of the nuclear fuels. Among these solutions, the inert matrix fuels (IMF) are proposed in this thesis. In seven chapters the author presents, the context and the state of the art, the different matrix, the calculi codes such as APOLLO2 or TRIPOLI4 needed to the neutronic analysis, the different fuel assemblies (CERMET UO{sub 2}, MOX, PuO{sub 2} and PuO{sub 2}-UO{sub 2}), the efficiency of the control rods in the case of the PWR, the cross sections problem, preliminary reflexions on critical accidents. (A.L.B.)

CERN Document Server

The near infrared (NIR) upgrade to the Robert Stobie Spectrograph (RSS) on the Southern African Large Telescope (SALT), RSS/NIR, extends the spectral coverage of all modes of the visible arm. The RSS/NIR is a low to medium resolution spectrograph with broadband imaging, spectropolarimetric, and Fabry-Perot imaging capabilities. The visible and NIR arms can be used simultaneously to extend spectral coverage from approximately 3200 A to 1.6 um. Both arms utilize high efficiency volume phase holographic gratings via articulating gratings and cameras. The NIR camera is designed around a 2048x2048 HAWAII-2RG detector housed in a cryogenic dewar. The Epps optical design of the camera consists of 6 spherical elements, providing sub-pixel rms image sizes of 7.5 +/- 1.0 um over all wavelengths and field angles. The exact long wavelength cutoff is yet to be determined in a detailed thermal analysis and will depend on the semi-warm instrument cooling ...

Science.gov (United States)

We report on recent progress and improvements in the metal-organic chemical vapor deposition (MOCVD) growth of mid-infrared lasers and using a high speed rotating disk reactor (RDR). The devices contain AlAsSb active regions. These lasers have multi-stage, type I InAsSb/InAsP quantum well active regions. A semi-metal GaAsSb/InAs layer acts as an internal electron source for the multi-stage injection lasers and AlAsSb is an electron confinement layer. These structures are the first MOCVD multi-stage devices. Growth in an RDR was necessary to avoid the previously observed Al memory effects found in conventional horizontal reactors. A single stage, optically pumped laser yielded improved power (greater than 650 mW/facet) at 80K and 3.8um. A multi-stage 3.8-3.9um laser structure operated up to T=170K. At 80K, peak power greater than 100mW and a high slope- efficiency were observed in gain guided lasers.

Energy Technology Data Exchange (ETDEWEB)

Ventilation systems must ensure high room air quality with minimum energy consumption in all states of operation. Systems for ventilation on demand are increasing their market share. (orig./MSK) [Deutsch] Oberste Aufgabe von Raumlufttechnischen Anlagen ist die Sicherstellung guter Raumluftqualitaet bei minimalem Energieverbrauch unter allen Betriebsbedingungen. Um dieses Ziel zu erreichen, setzt sich am Markt zunehmend die bedarfsgeregelte Lueftung durch. (orig./MSK)

Energy Technology Data Exchange (ETDEWEB)

Resistance to thyroid hormone (RTH) is an autosomal dominant disease caused by mutations in the human thyroid receptor beta gene on chromosome 3. Individuals with RTH have an increased incidence of attention deficit hyperactivity disorder (ADHD). The purpose of this study was to search for developmental brain malformations associated with RTH. Forty-three subjects (20 affected males [AM], 23 affected females [AF]) with resistance to thyroid hormone and 32 unaffected first degree relatives (18 unaffected males [UM], 14 unaffected females [UF]) underwent MRI brain scans with a volumetric acquisition that provided 90 contiguous 2 mm thick sagittal images. Films of six contiguous images beginning at a standard sagittal position lateral to the insula were analyzed by an investigator who was blind with respect to subject characteristics. The presence of extra or missing gyri in the parietal bank of the Sylvian fissure (multimodal association cortex) and multiple Heschl`s ...

International Nuclear Information System (INIS)

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). (HP).

Energy Technology Data Exchange (ETDEWEB)

This paper presents a series of modeling experiences and problems in simulating the thermal-hydraulic behavior of large PWR steam generators using the RELAP4 and RELAP5 computer codes. Sensitivity studies investigating the heat transfer characteristics of both once-through and U-tube steam generators are discussed. Suggestions and recommendations are given for effective use and potential future improvements of these codes.

International Nuclear Information System (INIS)

Various electrochemical techniques are available to continuously monitor corrosion in conditions simulating those on the secondary side of PWR steam generators. This paper reviews those electrochemical techniques which are potentially useful to measure denting in tube-support crevices in situ. Attention is also given to corollary needs for monitoring the water chemistry which leads to corrosive attack. Finally some suggestions are offered for corrosion monitoring in autoclaves, model boilers and operating steam generators.

Energy Technology Data Exchange (ETDEWEB)

A review and a number of extracts are given of the statement made by the acting chairman of the CEGB at a press conference on the publication of documents in support of the case for the building of the proposed Sizewell B PWR. The documents comprise the CEGB Statement of Case proper, the Reference Design, the Pre-Construction Safety Report and some 300 supporting reports. Objectors have eight months to study the reports before the public inquiry into the CEGB's proposals due to open in January 1983.

International Nuclear Information System (INIS)

The University of Michigan (UM) is a member of a team of researchers, including the universities of Florida, Texas, and Tennessee, along with Oak Ridge National Laboratory, developing robotic for hazardous environments. The goal of this research is to develop the intelligent and capable robots which can perform useful functions in the new generation of nuclear reactors currently under development. By augmenting human capabilities through remote robotics, increased safety, functionality, and reliability can be achieved. In accordance with the established lines of research responsibilities, our primary efforts during 1991 will continue to focus on the following areas: radiation imaging; mobile robot navigation; three-dimensional vision capabilities for navigation; and machine-intelligence. This report discuss work that has been and will be done in these areas.

Wastenet

... Project Details Title: Influence of increasing droplet concentrations on properties of stratocumulus clouds and climate Supervisor: Dr Alan Gadian Funded by: Engineering and Physical Sciences Research Council (EPSRC) Start date: October 2006 My project involves use of the UK Met Office Unified Model (UM) to calculate the global effect of modifying stratocumulus droplet concentrations on the earth's radiation balance, as well as use of ... Publications Latham, J; Rasch, P; Chen, CC; Kettles, L; Gadian, A; Gettelman, A; Morrison, H; Bower, K; Choularton, T (2008) Global temperature stabilization via controlled albedo enhancement of low-level maritime clouds, Philos. Trans. Roy. Soc. A, 366(1882), pp3969-3987. doi:10.1098/rsta.2008.0137 Current Students | Internal ...

CERN Document Server

An effect of laser-cooling of water was observed for the first time with a temperature decrease dT = -2.2 K after irradiation of liquid water surface by a powerful Ar-Xe pulse laser with a pulse energy of about 1 J and wavelength L = 1.73, 2.63 and 2.65 um. The discovered effect can apparently be ascribed to the optical excitation of vibrational states of H2O molecules followed by an endothermic consolidation of chemically active excited molecules into a quasi-stable cluster-like structure. The measured time dependences of the cooling effect show that a typical life time of the new state of water amounts to hours. It has also been shown that the life time of the excited vibrational molecular states due to a radiation trapping effect can be estimated to at least hundreds of seconds.

British Library Electronic Table of Contents (United Kingdom)

Background/Purpose: Congenital esophageal stenosis (CES) is a rare malformation. Endoscopic dilations represent a therapeutic option. This study retrospectively evaluated the efficacy and safety of a conservative treatment of CES. Patients and Methods: Patients diagnosed with CES since 1980 by a barium study or endoscopy were reviewed. Endoscopic ultrasonography (Olympus UM-3R-20-MHz radial miniprobe, Olympus Corporation, Tokyo, Japan), available from 2001, allowed for the differential diagnosis of tracheobronchial remnants (TBR) and fibromuscular hypertrophy (FMH) CES. All children underwent conservative treatment by endoscopic dilations (hydrostatic and Savary). Results: Forty-seven patients (20 men) had CES. Fifteen were associated with esophageal atresia; and 8, with Down syndrome. Mea...

Energy Technology Data Exchange (ETDEWEB)

Experiments with fresh PWR fuel assemblies were performed to assess the {sup 252}Cf-source-driven frequency analysis method for measuring the subcriticality of spent fuel. The measurements at the Babcox and Wilcox Critical Experiments Facility mocked up between 17x17 fuel pins (single assembly) and a full array of 4961 fuel pins (about 17 fuel assemblies) in borated water with a fixed B concentration. For the full array, the B content of the water was varied from 1511 at delayed criticality to 4303 ppM. Measurements were done for various source-detector-fuel pin configurations; they showed high sensitivity of frequency analysis parameters to B content and fissile mass. Parameters such as auto and cross power spectral densities can be calculated directly by a more general model of the Monte Carlo code (MCNP-DSP). Calculation-measurement comparisons are presented. This model permits the validation of neutron and gamma ray transport calculational methods with ...

International Nuclear Information System (INIS)

We obtained the ratios of "1"3"4Cs/"1"3"7Cs and "1"5"4Eu/"1"3"7Cs in spent PWR fuels with gamma scanning equipment of irradiated material examination facility. The fuel segments, of which the burn-up is about 40 GWD/MTU and its cooling time is 8.4 years, are prepared in Post Irradiated Examination Facility and transported to IMEF. By considering of multi-peaks of "1"3"4Cs and "1"5"4Eu, we obtained the relative efficiency of the gamma scanning system as a function of energy. And finally we obtained the number ratios of radioactive nuclides in 72 fuel pellets, radioactive "1"3"4Cs/"1"3"7Cs and "1"5"4Eu/"1"3"7Cs. (author). 4 refs., 27 tabs., 28 figs.

International Nuclear Information System (INIS)

High resolution Monte-Carlo simulations show that the neutron spectrum, fuel burnup and fuel temperature feedback effect of a PWR core loaded with Thoria-based fuel (Th/Pu-O_2) do not significantly differ from the MOX fuelled one due to the similar neutronic characteristics of both fertile materials (Th-232, U-238). The core physics of this fuel variant is characterized by an enhanced moderator/void temperature coefficient (by factor 2.4) and high incineration rate for Pu (approx. 60 %). A PWR core loaded with the Molybdenum-based inert matrix fuel (IMF) - in contrast to MOX-, shows a harder spectrum, resulting in small temperature coefficients of reactivity and particularly in a higher fuel depletion rate as well as an enhanced TRU reduction performance. The incineration of Pu amounts to 46 % resulting, in turn, in generation of minor actinides of about 10 % of the total Pu consumption. The higher excess reactivity resulting from the initial ...

Energy Technology Data Exchange (ETDEWEB)

The NUclear Power Engineering Corporation (NUPEC) has developed IMPACT-SAMPSON code to analyze integral behavior of light water nuclear power plants under severe accident conditions. IMPACT-SAMPSON's distinguishing features include interconnected hierarchical modules and mechanistic models covering a wide spectrum of scenarios ranging from normal operation to severe accident events, and high-speed simulation on parallel processing computers. The integral plant behaviors of typical PWR and BWR under severe accident conditions have been analyzed with the IMPACT-SAMPSON code. The PWR plant analyzed was the three-loop, steel-dry containment type with 2,440 MWt. The AE accident scenario was supposed, that is, LOCA by 6-inch hot leg failure followed by accumulated water injection, but no ECCS and containment spray activation. The BWR plant analyzed was the 3,293 MWt BWR-5, Mark-II containment type. The TQUV accident scenario was supposed, ...

International Nuclear Information System (INIS)

Denting studies have been undertaken in order to assess the influence of the most important parameters which could initiate corrosion of the carbon steel occurring in the tube-tube support plate crevices of some PWR steam generators. Tests have been carried out in model boilers where feedwater was polluted with sea or river water. Specific effects of chloride or sulfate and influence of oxygen content, magnetite addition and pH value were investigated. In magnetite prepacked crevices, denting is obtained within 1000 hrs for seawater pollution of 0.3 ppm chloride at the blowdown. In neutral chloride or in river water, denting is observed only with oxygen addition. Denting prevention is effective in the case of an on-line addition of phosphate, boric acid, or calcium hydroxide. For denting stopping, boric acid or calcium hydroxide is efficient even with a high seawater pollution. Soaks cannot stop denting if they are not followed by an on-line treatment (boric acid, ...

Energy Technology Data Exchange (ETDEWEB)

This project evaluated the feasibility of using a low-concentration (approx. 0.5 wt %) chemical cleaning process to remove corrosion product deposits from steam generator surfaces and magnetite from tube-to-support plate crevices of PWR steam generators. The primary objective was to develop a dilute process that could be safely applied at scheduled intervals, such as during normal refueling outages, to maintain a clean operating condition in the steam generator. The dilute chemical cleaning process developed in this project was demonstrated successfully on two model generators which were operated on faulted chemistry by DOE/CRC at Commonwealth's State Line Facility. Unit 5 was cleaned after 48 days of operation with 1% seawater fouling, and Unit 6 was cleaned after 112 days of operations with Lake Michigan water. This report describes work leading to the model generator cleaning demonstrations and provides details of the cleaning operation for each model ...

Energy Technology Data Exchange (ETDEWEB)

In this study, the adoptable essential technologies and reference design concept of the advanced reactor were developed and related basic experiments were performed. (1) Once-through Helical Steam Generator: a performance analysis computer code for heli-coiled steam generator was developed for thermal sizing of steam generator and determination of thermal-hydraulic parameters. (2) Self-pressurizing pressurizer : a performance analysis computer code for cold pressurizer was developed. (3) Control rod drive mechanism for fine control : type and function were surveyed. (4) CHF in passive PWR condition : development of the prediction model bundle CHF by introducing the correction factor from the data base. (5) Passive cooling concepts for concrete containment systems: development of the PCCS heat transfer coefficient. (6) Steam injector concepts: analysis and experiment were conducted. (7) Fluidic diode concepts : analysis and experiment were conducted. (8) Wet thermal ...

International Nuclear Information System (INIS)

Characteristic study for the recycled fuel cycle, MOX fuel and Th-MOX fuel in PWR was performed with the comparison of 4 w/o UO2 fuel. It was assumed that there are no limit in reprocessing and no technical difficulty in recycling of spent fuel. The effect of recycling, plutonium composition, conversion ratio, MTC, FTC was investigated to each cycle. (Th+Pu)O_2 recycle option was advantageous because the loading amount of plutonium could be reduced from 8.3 w/o at once-through cycle to 3.5 w/o. (Th+Pu)O_2 recycled fuel was known to be higher Pu-239 consumption rate and more Pu-240(242) production rate. The (Th+U)O2 and (U+Pu)O2 once-through fuel cycle revealed high conversion ratio. The (U+Pu)O_2 recycled fuel cycle, however, showed low conversion ratio. Safety of each cycle was ensured by negative MTC and FTC

Energy Technology Data Exchange (ETDEWEB)

Thermal-hydraulics analysis can be used to determine location and magnitude of leaks inside a pressurized water reactor (PWR) containment, as required by plant technical specifications. The major advantage of this detection method is that it minimizes radiation exposure of maintenance personnel because most of the leak detection process is performed from the control room outside the containment. In addition, such a program allows for the elimination of pipe whip restraints and jet impingement shields, eliminating costs for maintenance of these supports and shields in older plants and lowering construction costs for new plants. Previously, only simple single-node containment models were used for determining leakage magnitude. This paper presents a more sophisticated multinode approach for determining the magnitude and location. The resulting sensitivities to leak can be programmed into the plant's computer system. In this way, the plant's computer ...

International Nuclear Information System (INIS)

The applicability of the thermal response of an electrically heated simulated rod mostly used in loss-of-coolant-accident (LOCA) experiments to that of a nuclear fuel rod is a concern for the safety evaluation of a reactor. The present analysis describes the characteristics of the thermal response for both electrically heated and nuclear fuel rods during typical reflood conditions for a PWR-LOCA. A model describing the radial temperature field in the rod is developed based on the scheme in HETRAP code by Malang and incorporated into a reflood analysis code, REFLA for that purpose. The calculations applied to the existing reflood tests gave good agreement with experiments, showing the validity of the present model. The analysis has shown that the nuclear fuel rod tends to give a lower clad temperature and a sooner quench time than the electrically heated rod in a typical reflood condition, due to the smaller gap heat transfer and smaller heat capacity of the ...

Energy Technology Data Exchange (ETDEWEB)

The primary scope of this study is to establish the analysis technology for the advanced reactor designed on the basis of the passive and inherent safety concepts. This study is extended to the application of these technology to the safety analysis of the passive reactor. The study was performed for the small and medium sized reactor and the large sized reactor by focusing on the development of the analysis technology for the passive components. Among the identified concepts the once-through steam generator, the natural circulation of the integral reactor, heat pipe for containment cooling, and hydraulic valve were selected as the high priority items to be developed and the related studies are being performed for these items. For the large sized passive reactor, the study plans to extend the applicability of the best estimate computer code RELAP5/MOD3 which is widely used for the safety analyses of the reactor system. The improvement and supplementation study of the analysis modeling ...

International Nuclear Information System (INIS)

The lateral bearing device is made of 7 lateral supports, each positioned to allow the displacement of the steam generator due to thermal or seismic effects. Each support includes a buffer plate that can be positioned on the steam generator using a position control assembly. This control assembly consists of a screw jack arrangement where the nut is fastened via an energy absorbing layer to a footplate that is fixed to the concrete wall of the steam generator enclosure. 4 figs.

International Nuclear Information System (INIS)

Axial offset anomaly (AOA) is caused by the deposition of crud on the fuel cladding of a PWR. When significant levels of crud build up on the cladding, boron can accumulate in the pores of the crud as a concentrated solution or solid phase, and cause the flux depression. Numerous studies have been conducted on the primary water chemistry to reduce the amount of crud in the primary circuit to avoid radioactivity buildup and unexpected power transition in the plant. However, experiments on the crud are restricted in the laboratory because the crud is a highly radioactive material. The objective of this study is to develop a test method for simulating the deposition of crud in a nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

The report deals with: (1) two-phase flow regime transitions, (2) liquid entrainment in break flow, (3) vapor pull-through, and (4) CCFL in horizontal ducts. The first three processes influence the mass flow through the break, whereas the fourth one imposes a limit on liquid flow from the steam generator through the hot leg break into the core. Correlations available in the literature which deal with these processes are presented and applied to a hot leg of a PWR, LOFT and Semiscale for quantitative estimates, as well as for determining the scale distortion in the latter two facilities.

International Nuclear Information System (INIS)

In PWR steam-generators, the crevice between tube and tube-support plate tends to fill with porous deposits during operation and acts as a concentration site for chemicals in the boiler water, which may lead to corrosion of the tube and tube-support-plate. The rate of concentration, the magnitude of the concentration factor and the rate of release of solute when conditions change are important parameters for devising strategies to minimize corrosion. Values of these parameters for salt concentration have therefore been measured in a laboratory simulation of the crevice and are used to formulate a model of the concentrating process.

International Nuclear Information System (INIS)

A safety analysis code, named as SPACE, for a pressurized water reactor is under development to obtain a licensing to be used for the PWR design and to hold entire proprietary rights. The task of KAERI is to develop the physical models and correlations which are required to solve the field equations. It can be divided into four parts; i) flow regime determination, ii) wall heat transfer, iii) wall and interfacial friction, iv) interfacial heat and mass transfer. This paper will describe the process to develop the models for the two-phase flow regime maps in the horizontal and vertical pipes.

Energy Technology Data Exchange (ETDEWEB)

The booklet presents general information and practical hints for the task of acquiring and evaluating the data describing investments and other expenditure and activities for pollution abatement measures taken by electric utilities. The information is intended as an aid for establishing standard criteria for assignment and evaluation, and for comparison and classification of pollution abatement measures. As a line of orientation, a catalogue of pollution control measures is given, arranged into the following sections: Fossil-fueled power plants; nuclear power plants (BWR and PWR); hydroelectric power plants; power transmission and distribution. (HSCH)

International Nuclear Information System (INIS)

Corrosion is increasingly becoming an important factor reducing the reliability of many nuclear power plant components. The significance is evaluated of corrosion phenomena with respect to the reliability of primary circuit components of LWR's, viz., the reactor pressure vessel, primary piping, steam generator, and fuel elements. The mechanism of corrosion phenomena is explained and methods of minimizing their effects are presented. An analysis is made of the needs to solve the corrosion problems of nuclear power plants from the point of view of Czechoslovak producers and research and development activities. International cooperation is reviewed and main problems are formulated on which the solution of corrosion problems of structural materials used in WWER type nuclear power plants should be focussed. (author).

International Nuclear Information System (INIS)

Existing applications of Alloy 800 are summarized, with particular reference to its use in various types of reactor. The need for a co-ordinated research and development programme is stressed, and the variables to be explored are outlined. The papers relating to the problem of corrosion and cracking in water and steam are considered. the strength and ductility of Alloy 800 is considered. Finally, sections of the summary deal with the use of Alloy 800 for (a) sodium cooled fast reactor boiler tubes; (b) the high temperature gas cooled reactor; and (c) PWR steam generator tubes. (U.K.).

International Nuclear Information System (INIS)

Although there is service experience of Alloy 800 as tubing for superheaters in conventional and nuclear (HTR) power stations and in PWR heat exchangers, there is no corresponding service experience in sodium-cooled fast reactor steam generators. However, some limited experimental studies have been made of corrosion behaviour, and of possible structure modifications and effects on mechanical properties which occur during exposure of this material to a high temperature sodium environment, and these are summarised in the paper. It is concluded that further work needs to be done before Alloy 800 can be confidently endorsed for use as tubing in fast reactor steam generators. (author).

Energy Technology Data Exchange (ETDEWEB)

Borehole stability is affected to a significant extent by the 3D local and regional stress field. Preliminary information on underground stress fields is provided by the World Stress Map, which shows N-NW stress at a depth of about 5000 m for the Voelkersen field. Earlier data analyses showed various directions in the range of 310-360 degrees. This was assumed to be a methodical error. An extensive study was carried out to evaluate and interpret all relevant information provided by borehole tests, borehole logs, and drill core measurements. [German] Standsicherheit und Stabilitaet von Bohrungen werden ganz wesentliche beeinflusst durch das umgebende dreidimensionale lokale und regionale Spannungsfeld. Fuer die Planung zukuenftiger (horizontaler) Bohrungen und die Erzeugung kuenstlicher Risse (''fracs'') spielt das Spannungsfeld eine bedeutende Rolle. Erste Hinweise ueber das regionale Spannungsfeld im Untergrund gibt die World Stress Map, in der ...

Energy Technology Data Exchange (ETDEWEB)

Compared to the reference year of 1990, CO{sub 2} emissions of the Federal Republic of Germany have been curbed by about 12%, primarily as a result of industrial backfitting and pollution abatement measures accomplished in the industrial infrastructure of the new Federal Laender of Germany. Federal Government policy sticks to the previous commitment, to reduce carbon dioxide emissions by 25% by the year 2005. Current forecasts and scenarios of future greenhouse gas emissions show that only immediate adherence to a very stringent reduction policy might ensure that this ambitious goal will be achieved. In this context, any change of the baseline data and scenarios hitherto used for progonostic assessments is a crucial factor, so that the article here discusses the impacts of a change in the nuclear generation scenario, as recently ventilated by the German Federal Government, and expected effects on public power supply. (orig./CB) [Deutsch] Ausgehend von dem Bezugsjahr 1990 sind die ...

Energy Technology Data Exchange (ETDEWEB)

Expression of IGF-2 and changes in its expression in response to systemic endocrine alterations have not been demonstrated for adipocytes. Adipocytes were induced to develop within cultures of 3T3-L1 cells using a medium containing 0.5mM isobutylmethylxanthine, 1uM insulin and 100ng hydrocortisone/ml for 48 hours of exposure. Cultures containing developing adipocytes were incubated with 10% pig serum and 1 uM insulin for several days. The resultant adipocyte cultures were then treated with either 10% pig serum, diabetic pig serum or hypophysectomized pig serum in DMEM for 48 hours. Adipocytes within the cultures were separated from undifferentiated cells using percoll density gradient centrifugation. Total RNA was isolated from adipocytes and dot blotted. Blots were probed with a {sup 32}P-cDNA probe for rat IGF-2. IGF-2 was expressed by the adipocytes and the pattern of expression showed specific differences between serum treatments; IGF-2 ...

Energy Technology Data Exchange (ETDEWEB)

The report describes the processing of TiSi{sub 2}, MoSi{sub 2} and Ti{sub 5}Si{sub 3} by means of metal injection molding (MIM). First, the sintering activities of the three materials were investigated. After this, the viscosities of different mixtures of organic binder and powders of the three materials were determined, and in the final stage, components were produced by injection molding, the binder was removed, and the components were sintered. TiSi{sub 2} in powder form could be sintered to more than 95% of its theoretical density after 4 h at 1386 C. Metallographic analyses proved leaktightness of the component at this density. In the case of Ti{sub 5}Si{sub 3}, it was found that this material requires very long sintering times and high sintering temperatures for sintering to about 94% of its theoretical density. Metallographic analyses showed that only about 90% of the theoretical density was reached. MoSi{sub 2} in powder form could be sintered to only 90% of its theoretical ...

International Nuclear Information System (INIS)

Full text of publication follows: The TUV NORD e.V. is an independent Technical Support Organisation (TSO) performing safety assessments in almost every field of technology. In nuclear safety the TUV can look back on more than 40 years of experience. In the last years in Germany PWR safety analyses were focussed on boron dilution events with the potential of reactivity transients. The possibility of coolant with a low boron concentration collected in localized areas of the reactor coolant system (RCS) can be caused by injection of coolant with less boron content from interfacing systems (external dilution) as well as separation of borated reactor coolant into highly concentrated and diluted fractions (inherent dilution). Inherent dilution can e.g. occur after reflux-condenser heat transfer after a small break loss of coolant accident (SBLOCA) with a limited operability of the emergency core cooling (ECC) systems. The TUV Nord e.V. was charged by German supervisory ...

International Nuclear Information System (INIS)

1 - Description of test facility: The LOBI facility is a 1/700 scale model of a four loop PWR and has two primary loops, the intact loop representing three loops and the broken loop representing one loop of a four-loop PWR. The reactor pressure vessel model contains an electrically heated rod-bundle with 64 rods and a heated length of 3.9 m. The nominal heating power is 5.3 MW. The downcomer is of annular shape. An upper head simulator is connected to the vessel. Each of the two primary loops contains a pump and a steam generator. The different mass flows in the loops are established by the pump speeds, since the two pumps are identical. Heat is removed from the steam generators by a secondary system. ECC water can be supplied from two accumulators, one for each loop. Cold or hot leg as well as combined injection can be simulated. The LOBI test facility is the only high pressure integral test facility within the European Communities (1982), ...

Energy Technology Data Exchange (ETDEWEB)

The lateral bearing device is made of 7 lateral supports, each positioned to allow the displacement of the steam generator due to thermal or seismic effects. Each support includes a buffer plate that can be positioned on the steam generator using a position control assembly. This control assembly consists of a screw jack arrangement where the nut is fastened via an energy absorbing layer to a footplate that is fixed to the concrete wall of the steam generator enclosure. 4 figs.

Energy Technology Data Exchange (ETDEWEB)

To get a considerable reduction of the radiotoxicity due to americium, a thermal neutron fluence of 2.10{sup 22} cm{sup -2} or a fast neutron fluence of 2.10{sup 24} cm{sup -2} is required. Irradiation in a thermal neutron flux leads to lower masses of {sup 234}U and precursors and of {sup 237}Np and precursors, but to higher curium masses and much higher neutron emission rates than irradiation in a fast neutron flux. Therefore, irradiation in a fast neutron flux has preference when multiple recycling is adopted. When once-through burning is applied, irradiation in a thermal neutron flux can be applied. Then irradiation in a HWR has preference above irradiation in a PWR or in a HTGR. (orig.).

International Nuclear Information System (INIS)

This standard provides requirements and guidelines for installation, inspection and testing activities that assure the quality of important mechanical parts of a nuclear power plant not covered by the ASME Boiler and Pressure Vessel Code, Section III, during construction. These parts include those mechanical systems and components whose satisfactory performance is required: for the plant to operate reliably; to prevent accidents that could cause undue risk to the health and safety of the public; or to mitigate the consequences of such accidents if they were to occur. The requirements of this standard deal with the protection and control necessary to assure that the requisite quality of those important parts of the plant are preserved from the time items are removed from storage or receiving until they are incorporated into the plant up to but not including fuel loading for PWR plants and the completion of cold functional testing for BWR and HTGR plants.

International Nuclear Information System (INIS)

For shut-down safety of the turbine generator (securing of auxiliary power operation after load shut-down and preventing the reaching of overspeed after load shut-down with disturbed turbine governing system) additional measures compared to those for superheated steam turbines are required for turbine generators in plants with pressurized water reactor (PWR) as well as those with boiling water reactor (BWR) . Equipment is described (e.g. overspeed govern or selecting connection, vacuum breaker, bypass valves, intercepting valves) which, depending on the own conditions of the individual turbine generator (e.g. run-up time, vacuum, enclosed energy), may be applied alone or in jointly. (orig.).

International Nuclear Information System (INIS)

The aim of the risk assessment consists of a comparative security evaluation for the SNR-300 and the PWR Biblis B. The failure analysis focusses on the reactor core; in addition, possible fission product release from the spent fuel pits is examined. By reliability analyses, the frequency of events leading to incidents is determined together with the probability of core destruction. In the accident analysis, the kind and frequency of failure of the activity barriers, i.e., primary system (reactorvessel) and inner and outer containment are investigated for the various incident sequences. The radionuclide release into the environment is classified into five different release categories. Besides internal failures, external causes (especially earthquakes and plane crashes) are considered under the aspect of their risk contribution. (RF).

International Nuclear Information System (INIS)

A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyroprocessing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DF. As a result of the study, TRU DF and LLFP removal efficiency have to be achieved more than 1.0E+04 - 1.0E+05 and 96%, respectively. (author)

International Nuclear Information System (INIS)

One of the alternative ideas to solve the spent fuel issues, the partitioning and transmutation (P and T) technology has been developed for decades. Moreover, the concept of LILW production from P and T are proposed by Bowman. A PEACER (Proliferationresistant, Environmental-friendly Accident-tolerant, Continuable and Economical Reactor), based on pyrochemical process and Pb-Bi coolant transmutation reactor, has been conceptually designed to be able to convert all PWR spent fuel into low and intermediate level waste for near-surface disposal. In this study, the acceptance criteria for near-surface disposal facility is derived by the methodology for establishment of acceptance criteria. Then acceptable TRU decontamination factor (DF) and LLFP removal efficiency in order to meet acceptance criteria is evaluated

International Nuclear Information System (INIS)

Level 1 and 2 probabilistic safety assessments (PSAs) for both internal and external events are being performed to meet one of the conditions for a construction permit for Wolsong units 2, 3, and 4 in Korea. These units are CANDU-6 Pressurized Heavy Water Reactors (PHWRs), and the study is the first comprehensive level 1 and 2 PSAs for CANDU type plants in the world. The detailed PSA includes and extensive fault tree, event tree analysis, human reliability analysis, and common cause failure analysis. Event trees have been developed for 35 internal initiating event groups. The preliminary results show that the total core damage frequency for Wolsong units 2, 3, and 4 each is similar to that for a typical PWR plant. (author).

International Nuclear Information System (INIS)

Denting phenomenon as experienced in PWR steam generators has been investigated in the laboratory of Monel-400 tubes and C-steel baffles combination. Isothermal corrosion tests have been carried out by exposing capsules, containing a crevice between Monel-400 tubes and C-steel plugs, in plausible corrodents at 300"0C. Results indicated that the denting phenomenon is strongly influenced by the chloride content in the solution. In addition, it is a time dependent process. Stress exerted on the tubes by the growth of corrosion product on the outside surface of C-steel plugs are enough to deform the Monel tubes. The results have been discussed on the basis of accelerated corrosion of C-steel by hydrolyzable metal chlorides. (author).

Energy Technology Data Exchange (ETDEWEB)

The Level 1 probabilistic safety assessment (PSA) for Wolsung(WS) 2/3/4 nuclear power plant (NPPs) in design stage is performed using the methodologies being equivalent to PWR PSA. Accident sequence evaluation program (ASEP) human reliability analysis (HRA) procedure and technique for human error rate prediction (THERR) are used in HRA of WS 2/3/4 NPPs PSA. The= purpose of this paper is to introduce the procedure and methodology of HRA in WS 2/3/4 NPPs PSA. Also, this paper describes the interim results of importance analysis for human actions modeled in WS 2/3/4 PSA and the findings and recommendations of administrative control of secondary control area from the view of human factors. (Author) 10 refs., 2 tabs.

International Nuclear Information System (INIS)

Sizewell B is Nuclear Electric's latest power station, and the Pressurised Water Reactor (PWR) design on which it is based represents a ''first'' for the UK. One of the integral components of the plant is the heating, ventilation and air-conditioning (HVAC) system, which performs a contamination control and gaseous waste management function for the site. During the commissioning of Sizewell B Power Station the extract systems of the HVAC plant underwent a procedure known as ''fingerprinting''. This entailed the characterisation of the facilities provided to test the filtration plant during its lifetime. The assessment of their adequacy was then used to identify necessary modifications and/or to propose the manner in which future in situ performance testing would be carried out. The paper outlines the basic principles and procedure that was used to ''fingerprint'' test systems during the commissioning of Sizewell B. A specific example is presented to demonstrate the ...

International Nuclear Information System (INIS)

Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostic system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items.

Energy Technology Data Exchange (ETDEWEB)

The development of new electro-optical instrumentation for studying the annular dispersed two-phase flow regime is described. The system measures the thickness of the water film and droplet size and velocity distributions which would be encountered in such a flow regime. The water film thickness is measured by an improved capacitance method with a short time constant using newly developed sensor electrodes. The electrodes are made flush with the inner wall of a cylindrical tube and do not disturb the flow. In the test equipment, steady, laminar flow of water along the inner wall of the tube is controlled by appropriate valves and a porous jacket while droplets are introduced by means of a special spray nozzle.

International Nuclear Information System (INIS)

Problems are discussed of heat exchange tubes of Westinghouse type vertical steam generators exhibiting corrosion damage such as point corrosion, planar corrosion, tube denting, corrosion stress cracking, crevice corrosion, fretting corrosion and intergranular corrosion. Attention is also paid to problems of WWER-440 type horizontal steam generators, where the level fluctuation area is critical; noncompact porous deposits of the corrosion products give rise to crevice effects and cause significant concentration of chloride ions and other additions. This problem can be partly resolved by a modification of the collector design at the level variation area. An additional measure is the production of steel 08Kh18N10T with a very low level of harmful elements and inclusions. (Z.M.). 3 figs., 11 refs.

International Nuclear Information System (INIS)

The CERL Code was developed to describe the solution chemistry of the water on the steam generating side of PWR reactors. It is designed to calculate the equilibrium species distribution resulting from the interaction of impurities, corrosion products, and additives in the aqueous solution. It calculates the extent of ion-ion interactions, the precipitation of insoluble species and the amount of solute that partitions into the vapor phase when some of the water evaporates. This knowledge of the bulk phase equilibrium distribution of species, especially the pH should be useful in describing the corrosion processes at the solid liquid boundary. The code does not calculate any changes in oxidation states or any rates of reaction. Therefore, it is incapable of calculating the actual corrosion rates. It is anticipated that it will be used as a subprogram of a larger program that will include the redox reactions and the rates of the reactions. The purpose of the code at ...

International Nuclear Information System (INIS)

After a brief review of the degradations occurring on tubes of Inconel 600 in steam generators of PWR power stations emphasis is put on the conditioning of the secondary water and more particularly on the condensate treatment in the units of Doel which work on heavily polluted brackish water. The important role of non-destructive testing and eddy-current testing is also pointed out, method developed by Laborelec. The operational experience shows that Belgian stations are nearly not concerned by the degradations mostly found in power stations in other countries which shows the efficiency of the conditioning of the secondary water. On the other hand, other problems have occurred, resulting from: damage caused by foreign objects; fouling of tube before commissioning, cracking of bends and at the limit of the dudgeoning and leaking plugs. (AF).

Energy Technology Data Exchange (ETDEWEB)

Recently, the leak-before-break (LBB) concept has been used successfully to eliminate some pipe whip restraints, snubbers and jet impingement shields from the primary reactor cooling system piping of pressurized water reactors. This has resulted in substantial savings in maintenance costs, reductions in radiation exposure of plant service personnel, and has enhanced the overall safety of nuclear power plants. This study provides guidelines to utilities in expanding the application of the LBB concept to additional pipe systems and it couples the concept with hardware optimization. Seven high energy piping systems were investigated for technical feasibility in using the LBB concept. The results indicate that some of these seven lines are good candidates for the leak-before-break application.

British Library Electronic Table of Contents (United Kingdom)

To estimate the success criteria of an operators 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 ...

Energy Technology Data Exchange (ETDEWEB)

The deliberation by the Nuclear Safety Commission was initiated on the alteration in reactor installation, as was required by the Ministry of International Trade and Industry. The alteration is the additional installation of the reactor No. 2 in the Sendai Nuclear Power Station, Kyushu Electric Power Co., Inc. It is a PWR power plant with thermal output of about 2,660 MW (electric output of 890 MW), to be installed, adjoining to the reactor No. 1 of the same type and capacity under construction. In the examination by MITI, it was confirmed that the technological capabilities for its construction and operation and the radiation protection measures in power generation are both sufficient. The contents of the examination include the siting conditions, the location and construction of reactor facilities, etc.

Energy Technology Data Exchange (ETDEWEB)

A model is described for simulating thermal hydraulic and chemical conditions within fuel crud deposits. Heat transfer takes place by wick boiling in which water flows through the porous deposit and evaporates into steam at the surface of chimneys. The transport and chemistry of dissolved species within the deposit is also modelled. This chemistry includes the equilibrium chemistry of Li/boric acid species, the equilibrium chemistry of Fe/Ni species and the radiolysis chemistry of water. The unique feature of this model is that the chemistry is coupled to the thermal hydraulics via the increase in the saturation temperature with the concentration of dissolved species. This has a profound effect on evaporative heat transfer within thick deposits, leading to conditions that explain the precipitation of LiBO{sub 2} and the possible formation of bonaccordite. The model helps understand several crud scrape observations, including why AOA is observed to occur for a crud thickness in the ...

Energy Technology Data Exchange (ETDEWEB)

By retrofitting the existing steam turbine dual purpose power plant with a gas turbine plant and a secondary waste heat boiler the Technische Werke Ludwigshafen AG have considerably improved the energy generation in energetic, economic and ecological terms. The extension of the existing system to a combined cycle process has lead to this positive effect. The erection of a boiler plant during the first two construction phases has fully met the optimistic expectations. (orig.) [Deutsch] Mit der Nachruestung eines vorhandenen Dampfturbinen-HKW um eine Gasturbinenanlage mit nachgeschaltetem Abhitzekessel haben die Technischen Werke Ludwigshafen AG ihre Energieerzeugung entscheidend in energetischer, oekonomischer und oekologischer Sicht optimiert. Insbesondere die Erweiterung des vorhandenen Systems zu einem GuD-Prozess fuehrt zu dieser positiven Bilanz. Die Errichtung der Kesselanlage in den ersten beiden Bauabschnitten hat die optimistischen Erwartungen voll ...

Energy Technology Data Exchange (ETDEWEB)

Licensing procedures are of great importance in the entire decision-making and planning process for erection of cogeneration power plants. The paper presented is a condensed version of the ASUE guide published in May 1999 and gives compact and topical information about legal and procedural aspects for orientation of people not yet familiar with the licensing procedures. An initial outline lists and characterises the procedures involved, which then are explained in greater detail, accompanied by flowsheets and diagrams. (orig./CB) [German] Genehmigungsverfahren besitzen im Entscheidungs- und Planungsprozess eine grosse Bedeutung. Um Planern, Bauherren und Behoerden hierzu einen kompakten und aktuellen Ueberblick bieten zu koennen, wurde dieses Referat als Kurzfassung der im Mai 1999 veroeffentlichten ASUE-Broschuere zusammengestellt. Sie bietet vor allem denjenigen eine Hilfestellung, die noch keine Erfahrungen mit den Genehmigungsverfahren gesammelt haben. ...

Energy Technology Data Exchange (ETDEWEB)

Biodiesel can be produced from numerous materials, including by-products of animal chain. In this scenario, the chicken's oil, that is located and an environment not explored for biodiesel production, can be a good alternative in South and Southeast Brazilian Region, where they are slaughtered around 9.100.000 chickens per day. In order to determine the specific consumption from a generator set with single cylinder 6.6 kW of power and generation capacity of 5 kW, using chicken oil biodiesel (B-100), were performed the bench test using a auxiliary tank, precision scale and an energy analyzer. Were conducted four treatments (25%, 50%, 75% and 100% of generating capacity). The worst SC was the engine at 25% of generation capacity (1.5 kW) and better with 75% of maximum load (3.75 kW) with a mean of 479.34 g kWh{sup -1}. By Turkey's test ant 5% probability there was a significant difference only for the first treatment. (author)

Energy Technology Data Exchange (ETDEWEB)

Melting in a cokeless cupola furnace fuelled with natural gas is a novel, energy-saving and environment-friendly process. In order to be able to monitor the processes inside the furnace with detailed mass and heat balances, an experimental furnace with an efficient measuring system was constructed in the framework of a research project financed by the BMFT and Messrs. Eisenwerke Dueker GmbH und Co. KG, Laufach, Germany. (orig./HS) [Deutsch] Das Schmelzen im kokslosen erdgasgefeuerten Kupolofen ist ein neues, energiesparendes und umweltfreundliches Verfahren. Um die Vorgaenge im Ofen mit umfassenden Stoff- und Waermebilanzen erfassen zu koennen, ist im Rahmen eines vom BMFT und der Firma Eisenwerke Dueker GmbH und Co. KG, Laufach, finanzierten Forschungsvorhabens, ein Versuchsofen mit umfangreicher Messeinrichtung gebaut worden. (orig./HS)

Energy Technology Data Exchange (ETDEWEB)

The current discussion on worldwide climate change suggests that the current situation is unusual or extreme, and that climate changes never - or hardly ever - occurred in the centuries before. The author discusses whether this is really the case, and whether air pollution abatement measures can really help. His answers are based on the findings of palaeoclimatology. [German] Verfolgt man die Diskussion um den derzeitigen Klimawandel, so gewinnt man den Eindruck, Aussergewoehnliches und Extremes wuerde geschehen, und man bekommt zudem ueber Beratungsgremien und Medien vermittelt, dass sich in den Jahrhunderten vor dem heutigen Klimawandel das Klima nicht oder nur wenig geaendert hat. Es wird auch der Eindruck erweckt, man koenne das Klima stabilisieren und durch Emissionsminderungsmassnahmen das Klima schuetzen. Ist Klimaschutz eine loesbare Herausforderung oder ueberschaetzen wir Menschen unsere Moeglichkeiten? Man kann versuchen, sich an die Beantwortung dieser ...

Energy Technology Data Exchange (ETDEWEB)

Much of the current technology on 3D-prestack depth migration is based on the Kirchhoff method and the traveltime information needed for this purpose is obtained by the ray-theory approximation. The main motivation driving these options is to reduce computations but it can also have an adverse effect on the quality of results. Experience with real data indicates that the corresponding poststack data migrated by the reverse-time method often yields superior results. Considerable computational efficiency can be obtained by employing nonuniform coarse grid spacing during the reverse-time migration. We followed this strategy for developing a parallel scheme for doing 3D- prestack depth migration. However, we worked only on a small subset of shot gathers whose determined by the Quasi-Monte Carlo method. The results were indistinguishable from those obtained by using a much larger population of uniformly spaced shot gathers. We present examples of migration of 3-D data. (author)

Energy Technology Data Exchange (ETDEWEB)

To study the biogeochemical behaviour, mobility and transport of trace metals in seawater (Se, Mo, Cd, Pb, Hg, Cu, Co, Fe, Ni, Zn), in suspended particulate matter (Mo, Cd, Pb, Cu, Co, Fe, Ni, Zn, Al, Mn) and in sediments of the inner and outer coastal regions, samples were collected on 3 separate cruises during a one year period (Mai 1993 - April 1994) at 20 stations in the coastal area of Mecklenburg-Vorpommern. Standard hydrographic parameters, nutrients and dissolved oxygen were also measured. Priority was taken to establish the methods for the determination of molybdenum and selenium. To study the behaviour of these two elements in detail, longterm measurements were carried out weekly between January 1993 and June 1994 at the `Messsteg/Warnemuende`. Because of parallel measurements correlations to biological, chemical and hydrographic parameters have been tested. The total database is summarized in the Appendix. The results are presented in 30 figures and 13 tables and are ...

Energy Technology Data Exchange (ETDEWEB)

The study examines the isothermal fatigue properties of novel ODS iron-base or nickel-base superalloys at temperatures of 850 C and 1050 C. The materials are different in grain structure and texture, so that particularly the effects of grain structures and textures can be studied. In order to also perform examinations of creep-fatigue interactions, various load cycles are applied. It is shown that the LCF-affected life of the grain structures of both alloy types is determined by the elastic modulus. The cyclic lifetimes determined by the conventional Manson-Coffin method for both alloy types exhibit differences of up to two orders of magnitude. Using the product of the total strain range and the elastic modulus, however, will yield precise life predictions. Under conditions of LCF stress only, the grain structure has no effect on the materials` service life, other than in the case of creep-fatigue, but the grain structure has a decisive influence on the damage mechanisms and the course ...

International Nuclear Information System (INIS)

Tube supports used in the tube bundles of PWR steam generators have consisted of mechanical devices located at intervals along the tube bundle. The presence of tube supports creates regions of restricted flow with altered flow patterns and increased pressure drop. An additional and very important effect is also the possibility of local complete vaporization or dryout occurring in the tube/support flow passage and crevices. The thermal/hydraulic conditions at which dryout occurs are of particular interest because of the possibility of the deposition of dissolved solids with the occurrence of dryout. As long term build-up of solid deposition could have a deleterious effect, knowledge of the conditions at which dryout occurs would possibly provide a means to avoid this build-up. A test program, sponsored by the Steam Generator Project Office of the Electric Power Research Institute, was conducted to determine the thermal/hydraulic conditions at which dryout occurred ...

Energy Technology Data Exchange (ETDEWEB)

During LOCA(Loss of Coolant Accident), 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 could be accumulated and be clogged in the recirculation sump screen. If debris blocked the sump screen, the pressure drop 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 at 1990. Considering the important of safety, US NRC published Regulatory Guide 1.82 Rev.3 incorporating the R and D findings and experiences in 2003. NEI ...

Energy Technology Data Exchange (ETDEWEB)

Fuel irradiation leads to a swelling resulting from the formation of gaseous (Kr, Xe) or solid fission products which are found either in solution or as solid inclusions in the matrix. This phenomena has to be evaluated to be taken into account in fuel cladding Interaction. Fuel swelling was studied as a function of burn up by measuring the corresponding cell constant evolution by X-Ray diffraction. This study was realized on Mixed Oxide Fuels (MOX) irradiated in a Pressurized Water Reactor (PWR) at different burn-up for 3 initial Pu contents. Lattice parameter evolutions were followed as a function of burn-up for the irradiated fuel with and without an annealing thermal treatment. These experimental evolutions are compared to the theoretical evolutions calculated from the hard sphere model, using the fission product concentrations determined by the APPOLO computer code. Contribution of varying parameters influencing the unit cell value is discussed. Thermal ...

Energy Technology Data Exchange (ETDEWEB)

Reactor pressure vessel (RPV) steels are subjected to neutron irradiation at a temperature of about 290 deg C. This radiation exposure alters the mechanical properties, leading to a shift of the brittle-to-ductile transition temperature toward higher temperatures and to a diminution of the rupture energy as determined by Charpy V-notch tests. This radiation embrittlement is one of the important aging factors of nuclear power plants. U.S. NRC recommended the basic requirements for the determination of the pressure vessel fluence by regulatory guide DG-1025 in order to reduce the uncertainty in the determination of neutron fluence calculation and measurements. The determination of the pressure vessel fluence is based on both calculations and measurements. The fluence prediction is made with a calculation and the measurements are used to qualify the calculational methodology. Because of the importance and the difficulty of these calculations, the method`s qualification by comparison to ...

Energy Technology Data Exchange (ETDEWEB)

The load-following operation of nuclear power plants will become inevitable due to the increased nuclear share in the total electricity generation. As a groundwork for the load-following capability of the Korean next generation PWRs, the state-of-the-art has been reviewed. The core control principles and methods are the main subject in this review as well as the impact of load-following operations on the fuel performance and on the mechanical integrity of components. To begin with, it was described what the load-following operation is and in what view point the technology should be reviewed. Afterwards the load-following method, performance and problems in domestic 900 MWe class PWRs were discussed, and domestic R and D works were summarized. Foreign technologies were also reviewed. They include Mode G and Mode X of Foratom, D and L bank method of KWU, the method using PSCEA of ABB-CE, and MSHIM of Westinghouse. The load-following related special features of Foratom`s N4 plant, KWU`s ...

Energy Technology Data Exchange (ETDEWEB)

Alloy 600 is used as a material for steam generator tubing in pressurized water reactors(PWR) due to its high corrosion resistance under PWR environment. In spite of its corrosion resistance, stress corrosion cracking(SCC) has occurred on the primary side as well as the secondary side of the tubing. Oxide on steel surfaces in aqueous solution above 100 .deg. C is composed of duplex film structure. Inner layer of the oxide is dense and less porous, which is formed by growth of oxide layer on metal surface. Outer layer of the oxide is loose adhesive, which is formed by dissolution precipitation mechanism. Growth processes occur at the metal/oxide and oxide/electrolyte interfaces and are controlled by transport of the layer forming species through the layer, i.e. by the inward diffusion of oxygen including electrolyte species and the outward diffusion of metal cations. Understanding of basic electrochemical behaviors about anodic dissolution and ...

International Nuclear Information System (INIS)

Alloy 600 is commonly used in the primary systems of PWR plants because of its excellent resistance to a stress corrosion cracking and pitting. But a stress corrosion cracking and pitting corrosion are occasionally observed under PWR conditions, which may be correlated with the passive film on the Alloy 600 surface. There is little information on the composition of films growing on the surface of Alloy 600 at high temperature. Therefore, an understanding of the basic electrochemical behaviors about an anodic dissolution and the passivation of the bare surface of metals and alloys provides important information about localized corrosions like a SCC and pitting. Oxide on the steel surfaces in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. Outer layer of the oxide is less adhesive, which is ...

Energy Technology Data Exchange (ETDEWEB)

Evaporation system for liquid radioactive waste process has been used in Korean PWR nuclear power plants. The system is the most desirable process for decontamination factor (DF) theoretically. However, during the operation of the system, various problems have been arising such as scaling, carry over, etc. Because these problems make DF low, advanced technologies for liquid radwaste process have been world widely developed instead of keeping evaporation system. The main goal of new technologies is ALARA, ease of operation, cost effectiveness and minimization of environmental effect. Korea Electric Power Corporation is currently developing a combined treatment process for liquid radwaste using Micro-filter, Ultra-filter, Reverse Osmosis (RO) membrane, etc for the purpose of partly enhancement of evaporator and of having an alternative liquid radwaste process system for new reactors. As a part of the above project, the feasibility study using the Rolled Fiber-Filter ...

Energy Technology Data Exchange (ETDEWEB)

Magnetic resonance imaging (MRI) as a diagnostic imaging tool relies on the generation of magnetic fields, whereas the computerized tomography (CT) uses X-radiation. The fundamental principle of MRI is the magnetic resonance of paramagnetic atomic nuclei. These nuclei, as e.g. protons (= hydrogen nuclei), are aligned in required orientation by application of a strong magnetic field. Upon simultaneous application of an electromagnetic high-frequency field perpendicular to the axis of the basic magnetic field, and in response to periodical changing of the electromagnetic field at a given frequency, the originally aligned paramagnetic nuclei are forced into a movement similar to that of a ``whipping top``. When the resonance frequency is shut off, the nuclei return to their former, aligned positions, inducing a weak signal in a coil. The series of signals generated by multiple repetition of this process of excitation of nuclei and their return to aligned rest is used as input to a ...

Energy Technology Data Exchange (ETDEWEB)

The further optimisation and improvement of the efficiency of internal combustion engines require the realisation of new technologies leading to a distinctively faster warm-up behaviour of the coolant and lubricants as well as of the engine components after a cold start. In order to achieve reduced fuel consumption and exhaust gas emissions with the help of heat management, the design criteria of innovative cooling systems need to be reflected and adapted to future requirements. The use of intelligent components within the cooling system, such as the 'Stand Alone Rotary Valve' as a thermostat's substitute or the use of coolant pumps with a rotary valve integrated into the pump's inlet chamber, offer new ways to realise in a decisively quicker and more flexible way the appropriate heating up and cooling down procedures at varying driving conditions. A description of both of the intelligent components for the cooling system is given in this paper. The ...

International Nuclear Information System (INIS)

Three simulated low-level reactor wastes were dried using a spray dryer-baghouse system. The three aqueous feedstocks were sodium sulfate waste characteristic of a BWR, boric acid waste characteristic of a PWR, and a waste mixture of ion exchange resins and filter aid. These slurries were spiked with nonradioactive iron, cobalt, and manganese (representing corrosion products) and nonradioactive cesium and iodine (representing fission products). The throughput for the 2.1-m-diameter spray dryer and baghouse system was 160-180 kg/h, which is comparable to the requirements for a full-scale commercial installation. A free-flowing, dry product was produced in all of the tests. The volume reduction factor ranged from 2.5 to 5.8; the baghouse decontamination factor was typically in the range of 10"3 to 10"4. Using an overall system decontamination factor of 10"6, the activity of the off-gas was calculated to be one to two orders of magnitude less than the nuclide release ...

International Nuclear Information System (INIS)

PWR plants have made efforts to maintain the long-term integrity of the steam generators (SG) by reducing the amount of corrosion products entering the secondary side of the SG. Iron entered the SG can cause several problems: degraded heat conductivity of the SG tubes in locations where iron is deposited, water level oscillations in the SG due to tube support plate hole blockage, and initiation and propagation of inter-granular attacks (IGA) and stress corrosion cracking (SCC). One of the most effective measures, high all-volatile treatment (AVT) chemistry has been applied to actual plants to reduce the flow-accelerated corrosion (FAC) coming from the carbon steel piping. The secondary water chemistry at Genkai NPS 1 and 2 changed, from the Low AVT chemistry to the High AVT chemistry, in November 2006. In this paper, we will describe the results of experiments in applying the use of High pH water in the secondary water system at Genkai NPS. (author)

Science.gov (United States)

Operating PWR units in the USA have experienced very severe corrosion of the tube support plate at the crevice between the tube and the support. This results in distortion of the plate and crushing of the tube (denting). The first task of this project required that currently available computational methods to estimate the pH attained by concentrating boiler water under various fault conditions such as condenser leakage of river waters and faulty operation of condensate polishing plant. Particular attention has been paid to systems in which sulfate predominates. In the second task, the mechanisms are discussed by which solutions become concentrated in porous deposits on a boiling heat transfer surface. It is concluded that more experimental data are needed to test the validity of existing models. High solution concentrations in the deposit may occur at a heat flux close to the critical value for drying out the base of the deposit. The pore to bulk concentration ...

Energy Technology Data Exchange (ETDEWEB)

In a PWR type reactor, a primary coolant circuit system using a steam generator is adopted in order to accelerate depressurization of a primary coolant circuit upon small rupture LOCA in which the pressure of the primary coolant circuit is moderately depressurized. A secondary coolant circuit depressurization valve is disposed to a main steam pipeline. The valve has a performance of automatically opening to remove heat by evaporation of water stored in SG for a short period of time when the pressure in the primary circuit is decreased to about 50kg/cm[sup 2] upon occurrence of LOCA or the like. Then, the secondary side of the SG is depressurized to about atmospheric pressure and gravitational water injection from a condensate tank is started. Further, a gas vent valve is disposed to a water chamber of the steam generator. The valve has a performance of automatically opening to discharge incondensible gas mixed to the primary coolant circuit to the outside of the ...

Energy Technology Data Exchange (ETDEWEB)

The objective of this research was to determine the extent of damage that occurs when two pipes experience an impact event due to one whipping against the other. The research was conducted through experimental and analytical approaches. The former required the development of a specialized impact machine that could accelerate a whipping pipe with sufficient energy to cause failure of a target pipe that was heated and pressurized to Pressurized Water Reactor (PWR) conditions. Damage was measured in terms of crushing, bending, and failure. The results of the tests permitted the correlation between pipes of a certain size and the damage they could cause when impacting with a certain amount of known energy. These results were used to evaluate the pipe whip criteria in the Standard Review Plan 3.6.2-4. It was established that the criteria conditions did not fully represent the results obtained experimentally. An analysis procedure to model the pipe whip event was ...

Energy Technology Data Exchange (ETDEWEB)

A submerged nuclear power station has been proposed as an alternative power station with a relatively low environmental impact for use by both industrialized and developing countries. The station would be placed 10 m above the seabed at a depth of 30--100 m and a distance of 10--30 km from shore. The submerged nuclear power station would be manufactured and refueled in a central facility, thus gaining the economies of factoryfabrication and the flexibility of short-lead-time deployment. To minimize the size of the submerged hull, horizontal steam generators are proposed for the primary-to-secondary heat transfer, instead of the more traditional vertical steam generators. The horizontal steam generators for SNPS would be similar in design to the horizontal steam generators used in the N-Reactors except the tube orientation is horizontal (the tube's inlet and outlet connection points on the tubesheet are at the same elevation). Previous RELAP5 input decks for horizontal steam ...

International Nuclear Information System (INIS)

A submerged nuclear power station has been proposed as an alternative power station with a relatively low environmental impact for use by both industrialized and developing countries. The station would be placed 10 m above the seabed at a depth of 30--100 m and a distance of 10--30 km from shore. The submerged nuclear power station would be manufactured and refueled in a central facility, thus gaining the economies of factoryfabrication and the flexibility of short-lead-time deployment. To minimize the size of the submerged hull, horizontal steam generators are proposed for the primary-to-secondary heat transfer, instead of the more traditional vertical steam generators. The horizontal steam generators for SNPS would be similar in design to the horizontal steam generators used in the N-Reactors except the tube orientation is horizontal (the tube's inlet and outlet connection points on the tubesheet are at the same elevation). Previous RELAP5 input decks for horizontal steam generators ...

International Nuclear Information System (INIS)

PWR steam generators have suffered from a variety of degradation phenomena. This paper identifies the corrosion-related defects and their probable causes and suggests approaches to correct and prevent corrosive activity. In the attempt to solve the degradation problems, research programs have concentrated on modifying materials, stresses, and the chemical environment in both new and operating steam generators. The following corrosion-related defects have been studied: tube wastage, denting, primary side (ID) intergranular stress corrosion cracking (IGSCC), OD-initiated intergranular attack (IGA), pitting, and corrosion fatigue. Plants affected by wastage have greatly reduced their problem by adopting an all volatile treatment (AVT). In the case of denting, a less aggressive chemical environment is recommended. Primary side IGSCC responds to temperature reduction, stress relief, and material improvements, while flushing and boric acid addition minimizes OD-initiated ...

Energy Technology Data Exchange (ETDEWEB)

The detection efficiency of gamma scanning system in irradiated materials examination facility has been measured. Gamma-ray sources used in this experiment are Cs-Co standard sources a PWR spent fuel rod in which {sup 134}Cs and {sup 154}Eu peaks are clearly identified in the energy region of 500 to 1,600 keV. The distance between source and detector is about 1.6 m. A slit type collimator with 3 mm-width window and 30 mm-thick lead block are installed between source and detector. The detector is a HPGe detector. This equipment is mainly used in gamma scanning of irradiated nuclear fuel. The measured detection efficiency seems to be 1.89 x 10{sup -6} % for 1 MeV gamma-ray. With these results the activities of unknown sources could be measured. This results are expected to be used in the measurement of the absolute distribution of gamma emitting nuclides in nuclear fuel.

International Nuclear Information System (INIS)

The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology', project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Second, with the Simulation Supervisory System, up to 11 analysis modules were executed concurrently in the parallel environment (currently, NUPEC uses IBM-SP2 with 72 process elements), to demonstrate the code capability and integrity. The target plant was Surry as a typical PWR and the initiation events were a 10-inch cold leg failure. The analysis is divided to two cases; one is in-vessel retention analysis when the gap cooling is effective (In-vessel scenario test), the other is analysis of phenomena event is extended to ex-vessel due to the Reactor Pressure Vessel ...

International Nuclear Information System (INIS)

Steam Generator (SG) tubes in PWR plant are periodically inspected using eddy current testing (ECT) method. In Japan, bobbin coil type dual function probe is used for full length inspection, but the detectability for circumferential crack is very poor, and to improve detectability for circumferential crack and supplement regular ECT, various kinds of multi segment eddy current probes and multi transducer ultrasonic testing (UT) method have been developed. ECT probes are constructed of multiple surfaceriding special winding differential type coils and UT probe consists of 16 transducers which are spaced equally around the probe circumference for 360deg wall coverage. Both of those EC and UT probes are designed effective to detect circumferential crack. On the other hand, various kinds of laboratory induced circumferential cracks have been made and destroyed to prove the detectability of these probes. (author).

Energy Technology Data Exchange (ETDEWEB)

Verification and validation issues have been perceived as important factors in the large scale deployment of knowledge-based digital systems for plant transient diagnostics and management. Research and development (R&D) is being performed on the IGENPRO package to resolve knowledge base issues. The IGENPRO approach is to structure the knowledge bases on generic thermal-hydraulic (T-H) first principles and not use the conventional event-basis structure. This allows for generic comprehensive knowledge, relatively small knowledge bases and above all the possibility of T-H system/plant independence. To demonstrate concept feasibility the knowledge structure has been implemented in the diagnostic module PRODIAG. Promising laboratory testing results have been obtained using data from the full scope Braidwood PWR operator training simulator. This knowledge structure is now being implemented in the transient management module PROMANA to treat unanticipated events and ...

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 process can be used for nondestructive ...

International Nuclear Information System (INIS)

In this paper, an investigation was performed on a failure pressure vessel, which was as an anti-freezing heater for General Gas Storage and Distribution (SGZ) system. Evident and serious deformation was observed on the body of the vessel. A metallurgical investigation was conducted to establish the mechanism and cause of deformation of the anti-freezing heater at Daya Bay PWR station in China. The investigation, which was performed on specimens cut from the most serious area deformed of the vessel, included macroscopic examination and microscopy examination. The results of the examinations showed that some lamellar pearlite in the microstructure were already spheroidized. It was confirmed that the vessel was operated at high temperature. Stress analysis for the vessel was conducted. And it was confirmed that, in ideal conditions, the vessel would be deformed at around 420 C. The overall results of the investigation showed that the failure of the protected ...

Energy Technology Data Exchange (ETDEWEB)

The prediction of two-phase flow regime in the horizontal pipings during a loss-of-coolant accident (LOCA) is important for safety analysis of a pressurized water reactor (PWR). The flow regime transition conditions for a horizontal two-phase air-water flow were studied using a large-height, horizontal rectangular duct test section. The duct dimensions were 700 mm in height, 100 mm in width and 28.3 m in length. The experimental criterion for the flow regime transition from the stratified to slug flow regimes, in terms of the local void fraction and the non-dimensional gas-liquid relative velocity, agreed qualitatively with the prediction by the Mishima-Ishii model that is based on an idea that the interfacial waves with the largest growth rate will develop into a slug. However, the transition in the experiment occurred at systematically lower (by about 40 %) relative velocities than the prediction by the Mishima-Ishii model. Therefore, an experimental correlation ...

International Nuclear Information System (INIS)

68 replaced carbon steel piping in secondary system of pressurized water reactor (PWR) has been investigated by visual examination for checking thinning conditions. It is well known that the flow-accelerated corrosion (FAC) was inhibited by traces of Cr in steel. Therefore, the chemical compositions of those steels have been measured. In addition, the micro structure and hardness of those steels have been investigated. And the relationship between those material variables and FAC rate was considered. As the results, (1) The Cr contents in those steels were below 0.1 wt% except one sample. Minute quantities of chromium increase the resistance against FAC. But the water velocity was thought to be the dominant factor rather than chemical composition in steel, at least such as below 0.1%Cr. (2) Hardness of all piping has been satisfied the specifications of each materials. The hardness of steels was not correlated with wall thinning rate. (3) The micro structure was ...

Energy Technology Data Exchange (ETDEWEB)

Steam generator tubes in nuclear power plants are periodically checked by means of eddy current probes. The output of a probe is composed of three types of signals: known events (rolling zone, support plates, U-bend part), noise (mainly metallurgical noise) and possible flaws. The latter are random transients, both in arrival time and in shape: they have to be detected and then estimated, before to be fed to the high level stages of a diagnostic system. The objective of the study presented is to develop a semi-automatic system, which could manage and process more than 1 M-bytes of data per tube and provide an operator with reliable diagnostics proposals within a few minutes. This can be achieved only by cooperation of several digital signal processing techniques: detection, segmentation, estimation, noise subtraction, adaptive filtering, modelization, pattern recognition. The paper describes some of these items.

Energy Technology Data Exchange (ETDEWEB)

A highly reliable control rod drive mechanism (CRDM) installed inside the reactor vessel has developed for use of an advanced marine reactor. This CRDM contributes to compactness and simplicity of the reactor system, and it can eliminate the possibility of a rod ejection accident. The CRDM works in the high temperature and high pressure water - 310degC and 12 MPa, the same atmosphere as the primary loop. Driving force is produced by a synchronous motor with the rotor of a permanent magnet, which has been developed. An innovative latch mechanism using separable ball nuts can latch driving shaft connecting the control rod and de-latch it for scram. The rod position detector using a magnetostrictive wire type sensor on the principle of Wiedeman effect has been developed, accuracy of which is verified to have a detecting error within 1.2 mm. Ball bearings for thrust and radial supports in rotation have been developed to be capable of working under the high temperature water for a long ...

Energy Technology Data Exchange (ETDEWEB)

The main purpose of this study is to develop a thermal hydraulic auditing code for the CANDU reactor, modifying the model of existing PWR auditing tool , i.e. RELAP5/MOD3. This scope of project is a fourth step of the whole project, applying the RELAP5/MOD3/CANDU+ version for the real CANDU plant LOCA Analysis and D2O leakage incident. There are three main models under investigation, i.e. Moody critical flow model, flow regime model of horizontal CANDU bundle, and fuel element heatup model when the stratification occurs, especially when CANDU LOCA is tested. Also, for Wolsung unit 1 D2O leakage incident analysis, the plant behavior is predicted with the newly developed version for the first 1000 seconds after onset of the incident, with the main interest aiming for system pressure, level control system, and thermal hydraulic transient behavior of the secondary system. The model applied for this particular application includes heat transfer model of nuclear fuel ...

Energy Technology Data Exchange (ETDEWEB)

Scenarios are developed for spent fuel that is taken out of the nuclear reactor and stored for 20 years before reprocessing, and three storage techniques which use a water pool, dry cask or vault are compared with respect to their costs. The storage price (storage cost per kilogram of spent fuel), which is employed as the economic index, is calculated on the assumption that all the charge is paid when the spent fuel is brought in the storage facilities. Four scenarios are assumed for spent PWR and BWR fuels to be stored in at-reactor (AT) or away-from-reactor (AFR) facilities. The capital costs cover the buildings of the storage facilities, equipment, decommissioning, casks for transportation and storage (for cask storage) and casks for transportation (for water pool or vault storage). Costs for operation and maintenance of the facilities are also considered in evaluating these methods. Evaluation results show that the dry cask method is the most advantageous for ...

International Nuclear Information System (INIS)

The SMART (System-integrated Modular Advanced ReacTor) which is a 330 MWt advanced integral PWR was developed by the KAERI (Korea Atomic Energy Institute) for electricity generation and seawater desalination. A thermal hydraulic evaluation and analysis of the SMART is performed by the TASS /SMR-S (Transient And Setpoint Simulation/System integrated Modular Reactor-Safety). The TASS/SMR-S code has various models reflecting the design features of the SMART such as the drift flux model, the core models (core power and core heat transfer model), the component models, and the specific models. One of the core models is the core heat transfer model. The role of this model is to calculate the heat flux and radial temperature profiles at a fuel rod surface using the relevant heat transfer correlations for all of the heat transfer modes. Also it is modeled to meet the requirements of the 10 CFR 50 appendix K EM model for the CHF (Critical Heat Flux) and post CHF conditions. ...

International Nuclear Information System (INIS)

Rapid corrosion of PWR steam generator carbon steel support structures and consequential denting of steam generator tubes led to considerable investigation of the mechanism of corrosion and for palliatives. The basic mechanism is now fairly well understood. Chloride present in the boiler feedwater from condenser leakage is concentrated in the support plate crevice as a result of the superheat present. This leads to the formation of a low pH acid ferrous chloride environment either through the hydrolysis of a weak base chloride such as MgCl_2 or the combined action of a neutral chloride with an oxidizing agent. Rapid attack of the carbon steel ensues with the Fe_3O_4 corrosion product forming at the metal/oxide interface. This oxide has a volume approximately twice that of the steel consumed and thus eventually fills the crevice between the tube and the support plate. Oxide growth continues leading to compression of the Alloy 600 primary tube and to distortion and ...

International Nuclear Information System (INIS)

The TRAC/PFI-MOD2 Version 5.3 code was assessed against six FLECHT-SEASET forced reflood tests (31504, 31203, 31302, 31701, 34209, and 31922) and two cylindrical core test facility (CCTF) tests [C1-19 and C2-6]. The objective of this study was to evaluate the clad thermal response predictive capabilities of the code with the newly added reflood model under large-break loss-of-coolant accident (LOCA) conditions in a pressurized water reactor (PWR). The TRAC model for the FLECHT-SEASET test facility was developed from a RELAP5 model. The test section was modeled using a vessel component with 23 axial levels, 1 radial ring, and 1 azimuthal cell. Test inlet and exit conditions were modeled using fill and break components, respectively. The measured lower and upper plenum test conditions were input to the model. The electrically heated rod was modeled using a rod component with 22 axial mesh points. The axial boundary of each mesh point coincided with a fluid cell ...

Energy Technology Data Exchange (ETDEWEB)

In Sweden, spent nuclear fuel will be encapsulated and placed in a deep geological repository. In this procedure, reliable and accurate spent fuel data such as discharge burnup, cooling time and residual heat must be available. The gamma scanning method was proposed in earlier work as a fast and reliable method for the experimental determination of such spent fuel data. This thesis is focused on the recent achievements in the development of a pilot gamma scanning system and its application in measuring spent fuel residual heat. The achievements include the development of dedicated spectroscopic data-acquisition and analysis software and the use of a specially designed calorimeter for calibrating the gamma scanning system. The pilot system is described, including an evaluation of the performance of the spectrum analysis software. Also described are the gamma-scanning measurements on 31 spent PWR fuel assemblies performed using the pilot system. The results obtained ...

Energy Technology Data Exchange (ETDEWEB)

The application of the LBB technology to the newly constructed PWRs has been approved in Korea for several high energy systems that can meet rigorous acceptance criteria. The LBB evaluation had been initiated for Yong-Gwang 3 and 4 units (YGN 3 and 4) which are in service, and subsequently performed for Ul-Chin 3 and 4 units (UCN 3 and 4) which are in construction. The LBB application in Korea is based on the USNRC requirements. The LBB evaluation for YGN 3 and 4 is to eliminate the dynamic effects associated with the postulated DEGB from design basis loads as well as to eliminate pipe whip restraints and jet impingement barriers. There were several issues on the application of LBB to the primary coolant loop and the pressurizer surge line. Of concern were material properties of carbon steel for the primary coolant loop, estimation of crack opening area at the pipe-to-nozzle interface considering the asymmetry, and the leakage crack size which barely meets the required margin of 2 in ...

International Nuclear Information System (INIS)

In the case wherein nonlinear seismic response analyses are carried out, the response values vary due to the variations in materials and modeling. In this paper, nonlinear analyses of several random variables are carried out using: i. a conventional method; ii. a two-point estimation method (i. and ii. are simplified methods); and iii. Monte Carlo simulation (detailed method) to examine the variability of the response in the excessive nonlinear range for seismic responses of shear walls. The analyses are performed to a PWR-3 loop type reactor building which is one of the most typical reactor buildings in Japan. The variations are considered in specified compressive strength of concrete, concrete damping factor, shear wave velocity of soil and shapes of shear stress-strain relation curves of shear walls. As the results by the two simplified methods closely matched the Monte Carlo simulation results, the appropriateness for applying the simplified methods to ...

International Nuclear Information System (INIS)

A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyro-processing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DF. As a result of the study, LLFP removal efficiency, especially Sr-90 and Tc-99, is proved to be a major nuclide which contributes to annual dose by human intrusion scenario rather than TRU DF. More than 98.5% of LLFP have to be removed to meet below dose constraint within the DF more than 5.0E+03. Besides, because of the ...

International Nuclear Information System (INIS)

A pyrochemical process has been introduced and utilized so that the transmutation of spent PWR fuel in PEACER can produce mainly low and intermediate level waste for near surface disposal. Major radioactive nuclides from PEACER pyroprocessing are composed of TRU and LLFP. In this study, the requirement for the final waste from PEACER is evaluated based on the methodology for establishment of waste acceptance criteria. Also, sensitivity analysis for several input parameters is conducted in order to determine acceptable decontamination factor (DF) and LLFP removal efficiency and to find out input parameter that extremely have an effect on DF. As a result of the study, LLFP removal efficiency, especially Sr-90 and Tc-99, is proved to be a major nuclide which contributes to annual dose by human intrusion scenario rather than TRU DF. More than 98.5% of LLFP have to be removed to meet below dose constraint within the DF more than 5.0E + 03. Besides, because of the ...

Energy Technology Data Exchange (ETDEWEB)

Heat transfer processes use fluids which are generally not pure and can react with transfer surfaces. These surfaces are subject to deposits which can be sediments harmful to heat transfer and to integrity of materials. For nuclear plant steam generators, sludge build-up accelerates secondary side corrosion by concentrating chemical species. A major safety problem involved with such a corrosion is the growing of circumferential cracks which are very difficult to detect and size with eddy current probes. With a view to understand and control this problem, it is necessary to develop a mathematical model for the prediction of sludge behavior in PWR steam generators. Based on fundamental principles, this work intends to use different models available in literature for the prediction of the phenomenon leading to the accumulation of sludge particles at the bottom (the tubesheet) of a PWR. For that, a three-dimensional simulation of magnetite ...

Energy Technology Data Exchange (ETDEWEB)

Damage survey of protective coats of modern gas turbine blade shows that most damages are not due to classic wear mechanisms such as oxydation or high-temperature corrosion but caused by foreign bodies, poor coating during manufacturing, or operation-caused cracks. Mere visual inspection of cracks is often not sufficient to tell whether cracks are superficial or whether they have already progressed into the base material. Non-destructive methods such as ultrasonic inspection or eddy-current testing are helpful tools but there is not yet a fully matured testing concept at hand. Metallographical tests can give important information about crack mechanisms and thermal, chemical and mechanical stresses.(orig.) [German] Die Schadenerfahrung mit Schutzschichten moderner Gasturbinenschaufeln zeigt, dass die meisten Schaeden nicht auf die klassischen Verbrauchsmechanismen wie Oxydation und Hochtemperaturkorrosion zurueckzufuehren sind, sondern durch Fremdkoerper, herstellungsbedingte ...

Energy Technology Data Exchange (ETDEWEB)

The nozzle-group regulation of steam turbines plays furtheron an important role in the operation of power stations owing to modern, adaptable control-technical valve timing possibilities. New procedures for a choice-connection of different nozzle areas via the control valves as well as the use of valve laps require, however, a differentiated consideration of the loss mechanism in the inlet area of the turbine, in order to be able to assess and minimize its specific heat consumption also at the operational points outside the layout- and calculation-technically fixed guarantee or valve points, respectively. The basic technical-physical stages to this are explained. (orig.) [Deutsch] Die Duesengruppenregelung von Dampfturbinen nimmt nicht zuletzt dank moderner, anpassungsfaehiger leittechnischer Ventilansteuerungsmoeglichkeiten weiterhin eine bedeutende Stellung beim Betrieb von Kraftwerken ein. Neue Verfahren zur wahlweisen Zuschaltung unterschiedlicher Duesenflaechen ueber die ...

Energy Technology Data Exchange (ETDEWEB)

Blades of modern steam turbines are designed for high efficiency and operational safety. Modern computer programs enable optimisation of design but factors like manufacturing, assembly, operation and downtimes still play an important role. Damage statistics show that blade damage still quite frequent. Selected cases from the Allianz damage assessment centre show some of the more frequent damage mechanisms. Damage is often caused when several factors come together. Prevention of follow-up damage requires early identification of beginning damage.(orig.) [German] Die Auslegung der Beschaufelung moderner Dampfturbinen hat die Vorgabe, einen hohen Wirkungsgrad bei gleichzeitig hoher Betriebssicherheit zu erreichen. Mit den heute zur Verfuegung stehenden Rechenprogrammen ist eine entsprechende Optimierung realisierbar. Fuer die langzeitige Betriebsbewaehrung haben aber Einflussgroessen aus Fertigung, Montage, Betrieb und Stillstand auch heute noch die gleiche Bedeutung wie in der ...

Energy Technology Data Exchange (ETDEWEB)

Heat pumps for residential space heating become an increasingly important alternative to the conventional heating system like gas or oil burner. They offer the opportunity to reduce CO{sub 2} emission associated with heating residential homes in Germany. High compressors efficiency and a wide operating map are required so that an economically viable heat pumps is achieved which meets the operational conditions for present and future heating systems. The design parameter of existing heating systems require relatively high condensing temperatures which can be achieved with dedicated compressor designs. The design of Scroll compressors specially adapted to these heat pumps is shown and their operation is explained. (orig.) [German] Waermepumpen fuer die Wohnraumheizung gewinnen an Bedeutung als Alternative zur konventionellen Gas- oder Oelheizung. Sie bieten die Moeglichkeit, die mit der Gebaeudeheizung verbundene Emission von Kohlendioxid in Deutschland zu reduzieren. Ein hoher ...

Energy Technology Data Exchange (ETDEWEB)

The position paper will provide the basis for further strategies on offshore wind power development in consideration of ecological and conservation aspects. [German] Das Positionspapier des Bundesministeriums fuer Umwelt, Naturschutz und Reaktorsicherheit (BMU) einschliesslich des Umweltbundesamtes (UBA) und des Bundesamtes fuer Naturschutz (BfN) ist Ergebnis der Arbeiten der BMU-Projektgruppe 'Windenergienutzung im Offshore-Bereich im Hinblick auf die BMU-Anliegen'. Es beschreibt den derzeitigen Stand einer Strategie zur umwelt- und naturvertraeglichen Erschliessung der Windenergienutzung auf See (Offshore). Es bildet die Grundlage fuer die Weiterentwicklung dieser Strategie und dabei insbesondere zur Abstimmung mit den Anliegen anderer Bundesressorts und den Kuestenlaendern, sowie zur intensiveren Einbeziehung beteiligter Verbaende und Fachkreise. Vor dem Hintergrund der zur Genehmigung eingereichten Antraege fuer Offshore-Windparks, mangelnder Erfahrung der ...

Energy Technology Data Exchange (ETDEWEB)

About 25 years after the last edification of a new large high voltage institute at Technical University of Karlsruhe and about 10 years afte the edification of the test lab at Kaiserslautern University, the Brandenburg Technical University of Cottbus had the opportunity to design new high voltage test facilities from the very beginning on and to realize it in a very short time. To review the project from the first ideas followed by the planning and realization phase and the final commissioning of the technical equipment, this book should be a contribution to spred the experiences made among interested people and to demonstrate the actual technical possibilities. To ensure an international exchange of these experiences, all co-authors to the trouble to translate their participation's also to the English language. (orig.) [German] Etwa 25 Jahre nach dem letzten grossen hochspannungstechnischen Institutsneubau in der deutschen Hochschullandschaft an der TH Karlsruhe, bzw. 10 ...

Energy Technology Data Exchange (ETDEWEB)

CNG vehicles suffer from an uncontrolled temperature rise of the gas inside the tank during the filling process and heat exchange with the environment leads to variable filling levels. A partly filled tank reduces the range of CNG vehicles and works as a impediment to the spreading of environmentaly more friendly CNG vehicles. The increase of the pressure inside the tank combined with a prolongation of the filling time beyond three minutes can reduce the deficit of the filling process. For economic reasons the time required for refuelling should be as short as possible without the need to operate the filling station with a critical pressure. To meet this target the current technique requires further improvement. (orig.) [Deutsch] Die betriebliche Praxis bei Tankvorgaengen von Erdgasfahrzeugen zeigt, dass waehrend des Tankvorganges die Temperatur des getankten Erdgases im Fahrzeugtank ansteigt. Waehrend und nach Beendigung des Tankvorganges findet ein Temperaturausgleich mit der ...

Energy Technology Data Exchange (ETDEWEB)

Molybdenum is an essential element for living organisms. Moreover its radionuclides may represent an incorporation risk for members of the public and/or radiation workers after a nuclear accident or a release of radioactive materials. However, only few reliable data on Mo biokinetics in humans were available. The results of recent tracer kinetic investigations with stable isotopes have shown several differences from the ICRP data with regard to the processes of intestinal absorption and of excretion. As a consequence, the dose coefficients calculated with a revised biokinetic model deviate from the ICRP estimates. By ingestion of {sup 99}Mo radionuclides with solid food, for example, the dose to the colon may be higher of a factor up to 1 order of magnitude, due to the fraction of non-absorbed material which traverses the gastro-intestinal tract. (orig.) [Deutsch] Molybdaen ist einerseits ein fuer Lebewesen essentielles Spurenelement, andererseits koennen radioaktive Mo-Isotope im ...

Energy Technology Data Exchange (ETDEWEB)

In order for fuel cells to be successful, a full-scale hydrogen infastructure is required. The HyTra concept is presented here (HYdrogen TRAnsform, Transfer and TRAnsport) involves combined production, storage and supply of hydrogen in a transportable trailer, i.e. it is both a hydrogen production unit and a mobile filling station. The trailer can be transported to the selected site, where it will produce gaseous hydrogen from electricity and water by electrolysis. A compressor pumps the gas into an internal pressure tank and compresses it to filling pressure. Filling takes place by the overflow principle via a flexible high-pressure line with a standardised H{sub 2} filling unit. (orig.) [German] Um die Marktdurchdringung der Brennstoffzellentechnik gewaehrleisten zu koennen, muss eine flaechendeckende Wasserstoffinfrastruktur aufgebaut werden. Das neue HyTra-Konzept (HYdrogen TRAnsform, TRAnsfer and TRAnsport) beruht auf der Kombination von Wasserstoff-Erzeugung, ...

Energy Technology Data Exchange (ETDEWEB)

The externally fired combined cycle (EFCC) process utilises a high temperature heat exchanger to transfer the heat of a dirty flue gas to a clean working medium. In comparison to other combined cycle concepts, like integrated gasification combined cycle or pressurized pulverized coal combustion, the problems of hot gas cleaning are avoided. The first part of the publication (BWK 5/02) deals with the possible concepts and the efficiency potential of the externally fired combined cycle. The applicability of metallic and ceramic heat exchanger materials are discussed. The second part summarizes the state of the art and presents the basic design of a ceramic heat exchanger. [German] Der extern gefeuerte Gasturbinenprozess arbeitet mit einem Waermeuebertrager, um ein Arbeitsmedium auf Gasturbineneintrittstemperatur zu erhitzen. Im Vergleich zu Kombiprozessen mit integrierter Kohlevergasung oder Druckkohlenstaubfeuerung entfaellt damit die Heissgasreinigung. Der erste ...

Energy Technology Data Exchange (ETDEWEB)

Several technological alternatives have been studied taking into consideration that one of the biggest problems of the electric power companies is to provide electric power during the peak consumption periods, which largest contribution to the increase of the demand comes from the residential sector, especially by the use of electric showers. One of the most promising alternatives is the pre-water heating system for reduced power showers, developed by Universidade de Campinas and Companhia Paulista de Forca e Luz. The goal of this system is basically to reduce demand during the peak periods, in order to avoid heavy investments by the electric power companies in generation, transmission and distribution of electric power directed to low acquisitive power customers, a sector in which the electric power price is not enough to recover such investments. The objective of this paper is to evaluate the total energy required in the construction of one of these systems and compare it to the ...

Energy Technology Data Exchange (ETDEWEB)

The distribution of graphite particles in graphite containing copper alloy was further improved very significantly using several procedures and technological modifications. The developed techniques attacked the graphite distribution problem in two ways. Realizing that clustering of very fine (5um) graphite particles is one of the two major problems, a pretreatment process has been developed using aluminum powders to deagglomerate graphite particles. Along with this, a two-stage stirring technique was used to first incorporate and then to distribute uniformly the deagglomerated particles in the melt. During this year, based on these developments, several components were cast to evaluate the castability of Cu alloy-graphite melts. In addition, machinability tests were done to clearly established that addition of graphite particles improve the machinability of copper MMC alloys over and above that of monolithic copper alloys. The results show that the machining chip ...

Energy Technology Data Exchange (ETDEWEB)

The results of the creep performance studies at temperatures from 700-1000 C with welds of alloy 800 HT, the manual shielded metal arc welds made with Githerm 85 and Grini 209 filler metals, as well as the MIG pulsed arc welds made with the Nicrofer S 206 and Nicrofer S 5520 filler metals, proved to be in very good agreement with the calculated characteristic values published on VdTUeV sheet 434 in comparative assessments based on creep values valid for a service period of 10 000 hours. The MIG pulsed arc weld made with the Nicrofer S 5520 filler metal achieved by far the best results and strength values comparable to those of the base material, whereas the values of the other welds were corresponding to calculated strength values of the base material reduced by 20%. (orig./CB) [Deutsch] Die im Temperaturbereich von 700-1000 C an Alloy 800 HT und den Elektrodenhandschweissverbindungen mit den Schweisszusaetzen Gritherm 85 und Grini 209, sowie den MIG-Pulsed-Arc-Schweissungen mit den ...

Energy Technology Data Exchange (ETDEWEB)

Pulmonary infections and tumors are a major cause of death in patients with AIDS. The combination of clinical, radiological, laboratory, and pathohistological data helps to narrow the spectrum of differential diagnoses or even allows a specific diagnosis in many patients. Nevertheless, an accurate diagnosis should be obtained as soon as possible during the clinical course of the illness to initiate treatment in time. Computed tomography (CT) has proven to provide promising results in the diagnosis of AIDS-related throacic diseases. The aim of this paper was to demonstrate the diagnostic capacities of CT in the context of particular AIDS-related thoracic pathologies. Additional information on the spectrum of pathological agents and on differential diagnostic signs is summarized. (orig.) [Deutsch] Pulmonale Infektionen und Tumore sind eine wesentliche Todesursache bei Patienten, die am erworbenen Immunmangelsyndrom AIDS leiden. In den meisten Faellen gelingt es, durch Zusammenschau ...

Energy Technology Data Exchange (ETDEWEB)

Two spreading experiments were performed at the FARO facility with prototypical core melts of a UO{sub 2}/ZrO{sub 2} weight percentage of 80/20. The objective was to obtain data on the spreading at flow rates of about 2 l/s of more than 100 kg prototypic high temperature oxide melt on a dry and wet stainless steel plate. For the second spreading test a shallow water layer of 10 mm was added on the substrate. Solutions for an isothermal spreading with a constant volume flux boundary condition in a sector with an angle {phi} are used to analyse the FARO L-32S experiment and to identify the source of discrepancies between the code results (THEMA, CORFLOW) and the experimental findings. The observed spreading behaviour of both FARO experiments can only be explained if an initial melt temperature below the liquidus temperature, i.e. about 120 K lower than the temperature measured by the UTS sensors is assumed. (orig.) [German] Zwei Ausbreitungsexperimente mit einer UO{sub 2}/ZrO{sub 2} ...

Energy Technology Data Exchange (ETDEWEB)

Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare.This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristica of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fatsuppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spinecho sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spinecho sequences in high ...

Energy Technology Data Exchange (ETDEWEB)

The Deutsche Post AG is a transport company that with approximately 55,000 vehicles owns one of the biggest fleets in Europe. Being aware of its responsibility in the field of environmental policy it is looking for an alternative solution of an environmentally friendly vehicle drive system that also takes into account economic efficiency. Extensive investigations have led to a new energy storage based on the zinc-air energy system that has been developed and manufactured by the Israeli Company Electric Fuel Ltd. First tests showed an extraordinarily high capacity potential, drive values and ranges, which had been considered as impossible until that point of time. After these tests the Deutsche Post AG decided together with other well-known partners at home and abroad to carry out a territorial test with the zinc-air energy system in order to obtain insight into the day-to-day capability, economic efficiency, environmental friendliness under real driving conditions and into the required ...

Energy Technology Data Exchange (ETDEWEB)

Normally, the alloy NiMo28 is used in the solution annealed and quenched condition in which it has a face centred cubic matrix structure. The matrix of the material is supersaturated with molybdenum and, at temperatures above 800 C, has a tendency to form intermetallic precipitates such as the Ni{sub 4}Mo-ordered phase leading to the embrittlement of the NiMo28-ordered phase leading to the embrittlement of the NiMo28 alloy during hot working. For this reason, the aim of these investigations was to optimise the alloy by reducing its tendency to embrittle. The TEM-analyses carried out served to investigate the precipitation of the material as a function of its iron content after ageing at 700 C. The change in hardness and in the lattice constants of the NiMo28-specimens with iron content were also determined. To improve the hot working properties of this material it is recommended that the iron content be kept to about 3.2 mass % in order to reduce the tendency of the alloy to ...

Energy Technology Data Exchange (ETDEWEB)

The first working meeting of the SAPIERR project about regional final storage of radioactive waste in the European Union was held in Piestany, Slovak Republic, on February 19 and 20, 2004. SAPIERR stands for Support Action: Pilot Initiative for European Regional Repositories. This is an independent study supported financially by the European Union within the 6th Research Framework Program. The background to the project is the debate about the feasibility of regional repositories for radioactive waste in the European Union, which has come up again especially with a view to the new accession countries and the draft of a waste management directive within the framework of the Nuclear Package. The results of the SAPIERR Project will be presented in Brussels at a concluding international seminar, most probably in October 2005. The seminar will be open not only to the participating countries but also to other interested European and non-European states. (orig.) [German] Am 19. und 20. Februar ...

Energy Technology Data Exchange (ETDEWEB)

For purposes of assessing the dumpability of wastes, Article 1 - Ordinance on the Environmentally Responsible Landfilling of Household Wastes (AbfAblV) - of the Ordinance on the Environmentally Responsible Landfilling of Household Wastes and Biological Waste Treatment Plants defines classificaton criteria for biologically and mechanically treated wastes destined for landfilling. The practical experiences that have been gathered with these classification criteria and values were evaluated in a questionnaire-based survey. This was done in particular for the purpose of verifying and validating proposals on the methodology of respiration and fermentation tests. A general finding has been that the application and implementation of the regulations of the AbfAblV is fraught with difficulties. This is evident for one thing in the frequency of analyses and for another in the difficulty of complying with the limit values of the classification criteria. The authors are in support of demands that ...

Energy Technology Data Exchange (ETDEWEB)

One part of the RWE measure catalogue in order to guarantee an environmental friendly and competitive electric power generation based on brown coal is to carry out measures improving the efficiency at existing steam turbines in RWE brown coal power plants. Since 1993 a total of 21 steam turbines with a gross capacity of 7,100 MW or net capacity of 6540 MW - this corresponds to approximately 70 % of the installed RWE brown coal power plant capacity - have been improved with an investment of approximately DM 500 million. The net block efficiency has been increased by 1.3 % on average. The planned net capacity increase of approximately 250 MW is still going to be achieved taking into account the pending enhancements. Nuclear power plant turbines have been successfully improved in the same way. Apart from the described retrofit programme measures to improve efficiency are carried out at further steam turbines of brown coal power plants. In the frame of this talk the measures taken are ...

Energy Technology Data Exchange (ETDEWEB)

A part of the waste materials arising in iron and steel manufacture is utilised physically, either internally for the recovery of iron or externally for the production of cement and nonferrous metals. Most of these materials can be used without prior processing. Iron and steel-relevant waste materials which at present are still landfilled or disposed of as hazardous wastes are not immediately suitable for physical recycling as secondary raw material. These waste materials have to be processed without exception before they can be used again in the existing steel and iron manufacturing plants. The results of the authors` own studies have clearly shown that the cupola furnace is suited for the use of a wide variety of waste materials. [Deutsch] Ein Teil der bei der Eisen- und Stahlerzeugung anfallenden Abfallstoffe werden entweder intern zur Rueckgewinnung des Eisens oder extern in der Zement- bzw. Nichteisenmetallgewinnung stofflich verwertet. Dabei handelt es sich ueberwiegend ...

Energy Technology Data Exchange (ETDEWEB)

The transversus perinei profundus muscle is a well known structure in found anatomical textbook. Fibres of this muscle are believed to form the so-called external urethral sphincter (musculus sphincter urethrae). Recently histomorphologic investigations have shown that there is no muscular connection between the musculus sphincter urethrae (external sphincter) and the muscle system of the pelvic floor. Furthermore, the external sphincter was found to be divided into parts: The transversely striated part (musculus sphincter urethrae transversostriatus) and the smooth part (musculus sphincter urethrae glaber). Similar to histomorphologic investigations, contrast-enhanced MR imaging has shown the musculus sphincter urethrae to be surrounded by fatty and connective tissue only. Neither in MRI nor in anatomical slices can any connection between the urethral sphincter and the muscle system of the pelvic floor be found. Thus, on the basis of the results presented in this work it is concluded ...

Energy Technology Data Exchange (ETDEWEB)

Pyrolysis and combustion of CH are investigated. In order to reduce the work required for the present combination of parameters, the following substances were selected: Hexachloroethane, hexachlorocyclohexane, hexachlorobenzene and hexachlorophene. The model substances were pyrolyzed or combusted in varying conditions, and the combustion or pyrolysis products were analyzed. Only the main products were of interest; trace components are important only as far as they may throw light on the reaction mechanisms. The furnace design resulted in incomplete combustion and pyrolysis reactions, so that products of all stages of combusition or pyrolysis were available for analysis. Reaction processes can be derived from the products. As an alternative to thermal treatment of refuse, biological degradation of chlorinated hydrocarbons was gone into. The efficiency of decomposition by microorganisms was to be compared with the efficiency of thermal destruction of chlorohydrocarbons. The ...

Energy Technology Data Exchange (ETDEWEB)

In technical combustors, flow and combustion processes inside the combustion chamber determine the design and also the safety of the plant. A modelling technique was developed at TU Dresden which comprises both numerical simulations and experimental data and thus achieves a high degree of transparency in its visualisation of the processes inside the combustion chambers under investigation. With the experience gained, numerical models of commercial simulation software (FLUENT, CFX) can be validated by measured values, and potential applications of the programs can be investigated. The first stage of experimental modelling consisted in isothermal (cold) modelling in consideration of flow-relevant similarity characteristics. In the reactive, non-isothermal models, the fuel/air ratio and temperature conditions inside the original combustion chamber were modelled as well. In order to obtain detailed data on the combustion conditions at the burner, measurements were made on a separate ...

Energy Technology Data Exchange (ETDEWEB)

On the basis of cylindrical roller thrust bearings it was systematically examined to what extent PVD-coatings are able to take over the function of EP/AW-additives. The bearings were tested under heavy-duty conditions in order to distinguish very fast the efficiency of different coating-substrate-systems. Several coatings were tested for their ability to protect an un-coated counterpart. So just the washers of the roller bearings were coated, the rollers stayed un-coated. Four Me-C:H-coatings showed the best performance and fulfilled the required criterion for roller bearings in the boundary friction: low loss of mass and hardly surface deviation. Material carryover from the carbonaceous coating to the 100Cr6 steel surface was developed by the Me-C:H-coatings during the tests. This mechanism was able to protect the un-coated rollers. Closer investigations were done with an ESMA analysis (electron beam micro range analysis) on ZrC{sub g}-coatings. It could be seen, that a reaction layer ...

Energy Technology Data Exchange (ETDEWEB)

For a wider application of GaAs single crystals for semiconductor devices a cheaper process to grow crystals with high purity and low dislocation density is required. According to todays knowledge the Czochralski method with a hot wall vessel should be the choice. The temperature of the vessel has to be 700deg C to avoid condensation of arsenic which vapourizes from the 1240deg C hot melt. Arsenic vapour is very agressive against all metals. Therefore the corrosion resistance of metals and alloys with a high melting point and also ceramics has been tested. All the alloys under investigation are corroded severely so that they have to be excluded as a material for the vessel. The metals tantalum, molybdenum and tungsten are more resistent, titanium forms initially a thick protection layer and further corrosion is greatly reduced. The ceramics investigated (TiB{sub 2}; ALN; Makor; BN) are not attacked by arsenic though they may store some arsenic. (orig./MM). [Deutsch] Fuer breitere ...

Energy Technology Data Exchange (ETDEWEB)

The influence of a decarburisation process during austenitising of the through-hardenable rolling bearing steel 100Cr6 (SAE 52100) on the rim zone properties of the martensitic through-hardened material was investigated by means of material analysis and diffusion calculations. For this purpose, two specimens were prepared under defined heat treatment conditions, and the near-surface carbon distribution was determined micro-chemically by using secondary ion mass spectrometry (SIMS). In part 1 of the present work, these concentration profiles are compared with the depth variation of the micro-hardness and with the distance curves of the residual stresses and the line broadening ({l_brace}211{r_brace} {alpha}'-Fe diffraction line) both measured by X-ray diffraction (XRD). In addition, microstructure investigations were performed. In part 2, a refined kinetics model of a diffusion-controlled reaction based on the finite element method (FEM) will be applied to the decarburisation ...

Energy Technology Data Exchange (ETDEWEB)

This report completes the documentation for the research project 'High Pressure Compressor - Preliminary Design as Basis for the Development of an Efficient and Environmentally Friendly Core Engine' which was funded by the Ministry of Economics of State Brandenburg. The objective of the project is to deliver a preliminary compressor aerodynamic design as well as design studies for an efficient, weight and cost improved compressor. The increase of stage pressure ratio and improved efficiency, whilst stage and blade count is reduced, has been achieved by advanced 3D methods. Compressor stability also at off-design conditions will be retained. The mechanical design focusses on a cost and weight optimised rotor not only for a conventional bladed discs but also for Blish stages. Various options for split casings have been developed and assessed. Alternative vortex reducers based on different design options have been carried out. The results from this project will be ...

Energy Technology Data Exchange (ETDEWEB)

During the last years one focus of German PWR safety analysis was boron dilution events with the potential of reactivity transients. Coolant with a low boron concentration could be collected in localized areas of the reactor coolant system e.g. by separation of borated reactor coolant into highly concentrated and diluted fractions (inherent dilution) which can occur during reflux- condenser heat transfer after a small break loss of coolant accident with a limited availability of the emergency core cooling systems. The TUeV NORD SysTec was charged by German supervisory authorities with the assessment of the safety analyses of boron dilution events presented by the utilities. These analyses are based on the simulation of boron dilution and transport processes in conjunction with a number of dedicated experiments. The analyses shall demonstrate that boron dilution events cannot lead to recriticality of the core. Hence the boron concentration at the core inlet has to ...

Energy Technology Data Exchange (ETDEWEB)

During the last years, boron dilution events with the potential of reactivity transients were an important issue of German PWR safety analyses. A coolant with a low-boron concentration could be collected in localized areas of the reactor coolant system, e.g., by separation of a borated reactor coolant into highly concentrated and diluted fractions (inherent dilution) which can occur during reflux-condenser heat transfer after a small break loss of coolant accident with a limited availability of the emergency core cooling systems. During the course of follower core assessments, TUV NORD SysTec appraises safety analyses of boron dilution events presented by the utilities. These analyses are based on the simulation of boron dilution and transport processes in conjunction with a number of dedicated experiments. The analyses demonstrate that boron dilution events cannot lead to recriticality of the core. Hence, the boron concentration at the core inlet has to be ...

Energy Technology Data Exchange (ETDEWEB)

Following a referendum in Italy in 1987, the four Nuclear Power Plants (NPPs) owned and operated by the state utility ENEL were closed. After closing the NPPs, ENEL selected a ''safestore'' decommissioning strategy; anticipating a safestore period of some 40-50 years. This approach was consistent with the funds collected during plant operation, and was reinforced by the lack of both a waste repository and a set of national free release limits for contaminated materials in Italy. During 1999, twin decisions were made to privatize ENEL and to transform the nuclear division into a separate subsidiary of the ENEL group. This group was renamed Sogin and during the following year, ownership of the company was transferred to the Italian Treasury. On formation, Sogin was asked by the Italian government to review the national decommissioning strategy. The objective of the review was to move from a safestore strategy to a prompt decommissioning strategy, with ...

International Nuclear Information System (INIS)

Since 1975 All Volatile Treatment (AVT) has been the preferred method for controlling the secondary system operating environment in Westinghouse PWR plants. However, since AVT provides no buffering action against corrodent species present in the water as trace contaminants, utilities have initiated programs which combine control of contaminant ingress with total steam generator sludge management. The earliest applications of boric acid, to control denting type corrosion, began in 1978 and have continued up to the present time. Boric Acid has also been added as an inhibitor for SCC/IGA type corrosion since 1985. There are now approximately 30 plants operating with boric acid or boric acid/morpholine chemistry in the secondary system, and a growing number of plants where morpholine is being used as an additive to maintain pH and reduce iron transport attributable to erosion/corrosion. The impact of these modifications in the operating chemistry environment are ...

Energy Technology Data Exchange (ETDEWEB)

The first Russian reprocessing facility, known as RT-1 (located at PA-Mayak in Ural region) was started on the radiochemical plant base in 1977. Nowadays RT-1 is the sole operating reprocessing plant in Russia. The main features of RT-1 is its broad spectrum of reprocessing spent nuclear fuels (SNF). The following spent fuel types are reprocessed: -) SNF from PWR reactors (WWER-440) and FB reactor (BN-600); -) SNF of transport ship reactors; -) production reactors SNF; -) research reactor spent nuclear fuel. The world-known technological processes are used at RT-1, but there are the following distinctive features. First, the universality of the three technological lines which allows not only the reprocessing of various SNF kinds, but also to implement the combined reprocessing of some types of them. Secondly, extraction of neptunium during SNF reprocessing which is used to implement its separate storage and for radioisotope production. Thirdly, target enrichment of ...

International Nuclear Information System (INIS)

This paper presents the regulatory experience gained from Wolsong Units 2,3 and 4 - Special Safety System Instrumentation Uncertainty for Trip Setpoint and Allowable Values. The equipment diversity method for the defense against common mode failure was applied to the transmitters of shutdown system number 2. However the Units experienced an unexpected drift problem with which the performance did not meet the Technical Specification (Tech Spec) Surveillance Requirements (SR). Discussed are the background, status and corrective actions, regulatory positions and issues to be solved for the drift problem. It was an instrument uncertainty methodology that the designer of safety system should have shown when the drift problem occurred. For deeper understanding of the problem, we present the background of Tech Spec SR for setpoints in Korean PWR and in CANDU reactors. The Setpoint Verification Test(SVT) and Calibration Test(CT) shall be achieved by recording sufficient ...

International Nuclear Information System (INIS)

Loading pattern optimization (LPO) for a PWR in nuclear power plant contains three parts: fuel assembly location optimization, burnable poison placement optimization, and used fuel assembly orientation optimization. To solve the former two parts, this paper devises an innovative stochastic evolutionary algorithm-Interval Bound Algorithm (IBA), which can optimize fuel assembly location and burnable poison placement together. IBA just uses the fuel assembly's infinite multiplication factor to get rid of unfavorable patterns and to explore new promising solution space. To solve the last part, this paper applies Estimation of Distribution Algorithms (EDAs), which also belong to evolutionary algorithms. These three parts depend on each other, so it is better not to solve them separately. In order to optimize these parts in a coupled way, we use Symbiotic Co-evolutionary Algorithm (SCA) to incorporate IBA and EDAs. This technique could reflect the real optimization ...

Science.gov (United States)

Among KEPCO's 9 nuclear power units, Korea Nuclear Unit No. 3, the Wolsung Nuclear Power Plant is the only CANDU-PHWR Unit, while the rest of 8 others are PWR units. The unit was designed by Atomic Energy of Canada, Ltd. of Canada, who also performed overall project management for the plant construction under the provisions and arrangement of the relevant contracts. The gross electrical output of the plant is 678.7 MWe and thermal output of the reactor is 2061 MWth. While these figures lead to lower plant efficiency than LWR counterparts, unit energy cost for fuel is more favorable than LWRs because natural uranium is utilized for the fuel bundles, some of which are already being fabricated domestically. Annual capacity factors for 1983 and 1984 could have been improved, if two major planned outages for the modification works on steam generator internals and one major forced outage from the heavy water spill incident could be eliminated. The heavy water ...

Energy Technology Data Exchange (ETDEWEB)

The feasibility was evaluated using MCNP-DSP, an analog Monte Carlo transport cod to simulate source-driven measurements. Models of an isolated Westinghouse 17x17 PWR fuel assembly in a 1500-ppM borated water storage pool were used. In the models, the fuel burnup profile was represented using seven axial burnup zones, each with isotopics estimated by the PDQ code. Four different fuel assemblies with average burnups from fresh to 32 GWd/MTU were modeled and analyzed. Analysis of the fuel assemblies was simulated by inducing fission in the fuel using a {sup 252}Cf source adjacent to the assembly and correlating source fissions with the response of a bank of {sup 3}He detectors adjacent to the assembly opposite the source. This analysis was performed at 7 different axial positions on each of the 4 assemblies, and the source-detector cross-spectrum signature was calculated for each of these 28 simulated measurements. The magnitude of the cross-spectrum signature ...

International Nuclear Information System (INIS)

Project RPS116, ''Implementation of Boric Acid in the Field,'' was designed to demonstrate that a selected steam generator boric acid treatment is effective in arresting the progressing of denting in an operating steam generator. The PWR nuclear steam generators chosen for the testing were those at the Indian Point Unit 3 nuclear site. Hydrogen monitoring measurements and eddy current examinations had indicated that the Indian Point Unit 3, Series 44 steam generators had already reached an advanced stage of denting and tube support plate ligament discontinuities were observed. The objective of the boric acid treatment was to reduce the rate of denting by attempting to reproduce in the field the positive results achieved with boric acid in laboratory-simulated denting tests. Laboratory testing has indicated that implementation of a four day low power (25% power) boric acid soak with 50 ppm boron as boric acid followed by maintenance of a 5-10 ppm boron level during ...

International Nuclear Information System (INIS)

In light of the recent rapid increase in the fossil fuel prices it is meaningful to evaluate the impact of these price changes in the economics of dual-purpose desalination projects producing electricity and fresh water simultaneously. The price of crude oil and LNG (Liquefied Natural Gas) has increased by about 200% and 100% during the past three or four years. The uranium price has also increased by nearly 500% during the same period. The purpose of this paper is to analyze and compare the economics of SMART (System-integrated Modular Advanced ReacTor) which is being developed as a small size PWR type and the LNG Combine Cycle coupled with MED (Multi-Effect Distillation) which are being acknowledged as promising energy sources for the future in Korea. The methods of analysis used in this paper are the lifetime leveled cost method for the power and water cost calculation and the power credit method for the total cost allocation. DEEP (Devaluation Economic ...

Energy Technology Data Exchange (ETDEWEB)

This paper reports on Run SB-CL-05, a test similar to Semiscale Run S-UT-8. The test results show that the core was uncovered briefly during the accident and that the rods overheated at certain core locations. Liquid holdup on the upflow side of the steam-generator tubes was observed. After the loop seal cleared, the core refilled and the rods cooled. These behaviors were similar to those observed in the Semiscale run. The Large-Scale Test Facility (LSTF) Run SB-CL-06 is a counterpart test to Semiscale Run S-LH-01. The comparison of the results of both tests shows similar phenomena. The similarity of phenomena in these two facilities build confidence that these results can be expected to occur in a PWR. Similar holdup has now been observed in the 6 tubes of Semiscale and in the 141 tubes of LSTF. It is now more believable that holdup may occur in a full-scale steam generator with 3000 or more tubes. These results confirm the scaling of these phenomena from ...

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 action time by using the MARS platform. ...

Energy Technology Data Exchange (ETDEWEB)

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

International Nuclear Information System (INIS)

A post-irradiation annealing study was conducted with use of reactor pressure vessel(RPV) steel A533B C1.1 base metal irradiated to a dose of 4.84x10"1"8 n/cm"2 at about 380 deg C. Microhardness and positron annihilation (PA) methods were used to obtain better understanding of the recovery of radiation hardening. Isochronal anneal experiments indicated that two recovery processes occur during annealing of irradiated specimens. The first recovery process occurs in the temperature of 280-305 deg C. The variations of Ip, Iw and R parameters indicated that the formation of vacancy clusters by vacancy aggromeration and the annihilation parameters measured indicated that the dissolution of carbon atoms decorated around vacancy-type defects and possible precipitates, and the annihilation of monovacancies give rise to the second recovery process. It was further indicated that radiation anneal hardening (RAH) in the range of 305-405 deg C between the temperature ranges for the two processes ...

International Nuclear Information System (INIS)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is formed by a dissolution and precipitation mechanism. Growth processes of the inner layer and the outer layer occur at the ...

ScienceCinema

...and it's really a pleasure to ...you and ...and for ...was shelled and then doses of pleasure for me to ...and my director general ...? and journal article ? ...but and yeah well that's um ? ...and ...and what could be achieved ? what might be the consequences ...? and ...and ...and ...and ...and ...structural because and ...over and hopefully is also serve the purpose to get ...principles and ...and ...and ...how to use them and future ...and and that ...and purposes and that's very important ...you and ...and ...and in the future ? and yeah ...true and ...and ...just and and and and and the order of nuclear physics a ...useful and ...too much ? and ...portable comes from and ...and ...and ...and ...no more ? how to knowledge and the and ...and ...and and keep ever seen all of all ? ...and ...and ...and what you're ...and ...and ...and you and ...and ...and ...and so when you keep that and and ...and ...? and ...and ...and ...the problems and the other side ? ...

Energy Technology Data Exchange (ETDEWEB)

The role of high-resolution computed tomography (HRCT) and magnetic resonance imaging (MRI) in the diagnosis of preoperative and postoperative complications caused by acquired cholesteatomas will be described in this paper. The pre- and postoperative imaging of the temporal bone was performed with HRCT and MRI. HRCT and MRI were performed in the axial and coronal plane. MRI was done with T2 weighted and T1 weighted sequences both before and after the intravenous application of contrast material. All imaging findings were confirmed clinically or surgically. The preoperative cholesteatoma-caused complications depicted by HRCT included bony erosions of the ossicles, scutum, facial canal in the middle ear, tympanic walls including the tegmen tympani, and of the labyrinth. The preoperative cholesteatoma-caused complications depicted by MRI included signs indicative for labyrinthitis, and brain abscess. Postoperative HRCT depicted bony erosions caused by recurrent cholesteatoma, bony defects ...

Energy Technology Data Exchange (ETDEWEB)

The staging of patients with multiple myeloma demands sensitive imaging methods for the assessment of the skeletal system. MRI allows for direct visualization of the bone marrow which exhibits five different infiltration patterns in multiple myeloma: 1. normal appearance of the bone marrow, 2. focal involvement, 3. homogeneous diffuse infiltration, 4. combined diffuse and focal infiltration, 5. ''salt and pepper'' pattern with inhomogeneous bone marrow signals due to multiple fat islands. The combination of T1w-SE and STIR sequences is best suited for detecting all infiltration patterns and for the differential diagnoses e. g. hemangiomas. With parallel imaging in MRI, acquisition times can be markedly reduced and whole-body screening of the bone marrow can be achieved within 30 min. MRI is superior to radiography for the detection of focal as well as diffuse infiltration. Multidetector computed tomography and especially 16- and 64-detector row ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this work was the examination of the coarse grain recrystallisation of the {gamma}-free ODS nickel-based alloy PM 1000 depending on the various parameters due to the processing during heat treatment. After isotropic hot compacting (HIP) of the mechanically alloyed powder, one observes a homogeneous sub-microscopic fine grain structure which can coarsen during high temperature heat treatment, due to sufficiently high driving force from the grain boundary energy via abnormal grain growth to 600 times its size. The setting of the elongated high temperature resistant recrystallisation structure is, however, not connected with this. The dependence of the sucess of re-crystallisation on the re-forming parameters (re-forming temperature and degree of re-forming) was shown by a socalled re-forming card. In order to achieve re-crystallisation to a coarse and aligned grain structure, apart from a certain absolute minimum degree of re-forming, the re-forming must occur within a defined ...

Energy Technology Data Exchange (ETDEWEB)

Patients with haemarthros of the knee were examined by MRI and arthroscopy to identify the bleeding source and to determine surgical or conservative therapy. A prospective study was performed on 120 patients who underwent MRI and arthroscopy, point lesions and bleeding sources were documented separately on a standardised form. Arthroscopy demonstrated a ruptured anterior cruciate ligament in 86%, meniscal tears in 55%, disruption of collateral ligaments in 17%, osteochondral lesions in 5% and tears of capsule or plicae in 13%. Disruption of cruciate ligaments caused haemorrhage in all but three cases. In contrast, only meniscal tears located very adjacent to the meniscal basement had bled. Those types of osteochondral lesions caused haemorrhage characterised on MRI by destruction of the subchondral plate and overlying cartilage. Severe lesions of the knee were diagnosed by MRI in 71% to 100%, slight lesions in 13% to 40% of the cases. Single, combined and bland lesions were accurately ...

Energy Technology Data Exchange (ETDEWEB)

Functional imaging of the pharynx used to be the domain of cineradiography, CT and ultrafast CT. The development of modern MRI techniques led to new access to functional disorders of the pharynx. The aim of this study was to implement a new MRI technique to examine oropharyngeal obstructive mechanisms in patients with obstructive sleep apnea (OSA). Sixteen patients suffering from OSA and 6 healthy volunteers were examined on a 1.5 T whole-body imager (`Vision`, Siemens, Erlangen Medical Engineering, Germany) using a circular polarized head coil. Imaging was performed with 2D flash sequences in midsagittal and axial planes. Patients and volunteers were asked to breathe normally through the nose and to simulate snoring and the Mueller maneuver during magnetic resonance imaging (MRI). Prior to MRI, all patients underwent an ear, nose and throat (ENT) examination, functional fiberoptic nasopharyngoscopy and polysomnography. A temporal resolution of 6 images/s and an in-plane resolution of ...

Energy Technology Data Exchange (ETDEWEB)

This report describes work carried out in the context of TurboTech Interim for the development of a system for monitoring stationary gas turbines for approaching the stability limit of the compressor. The requirements for the system components were defined and the suitability of different types and positions of pressure sensors were examined and evaluated. It was found very early in the work that, due to the complexity of the object being monitored, one would not succeed in finding a simple criterion for monitoring the pump limit. Rather, apart from the selection of suitable sensors and optimum positions, one must analyse the present signals in different ways and create a decision matrix from this. Existing work on this subject is mostly concerned with the phenomena in the context of experiments on experimental compressors or is not suitable for the requirements of stationary industrial gas turbines. The project is being carried out in the context of TurboTech II with the main aims of: ...

International Nuclear Information System (INIS)

The saturation of South Korea's at-reactor (AR) spent fuel storage pools will create a necessity for additional spent fuel storage capacity. Because the South Korean government has the plan to increase the number of nuclear power plants from 20 units (end of 2005) to 27 units by 2015, the increase of spent nuclear fuel generation will be accelerated. Because there is no clear national plan for spent nuclear fuel storage and disposal, the utility company (Korea Hydraulic Nuclear Power company) is planning to construct a spent fuel storage facility with 11 000 tHM capacity for Pressurised Water Reactor (PWR). This study is intended to predict the maximum allowable periods when the storage facility will be fully occupied with respect to the already fixed re-racking plan of spent fuel storage pools and construction of new nuclear power plants. The result from this study will be used as fundamental data for an efficient management of the spent fuel storage capacity up ...

Energy Technology Data Exchange (ETDEWEB)

The Control Rod Drive(CRD) nozzles for PWR nuclear power plants(NPP) house the control rod drives. The number of nozzle penetrations range from the mid-30's to over 100 in each reactor head. The integrity of CRD nozzles is very important, because the primary pressure boundary is established with the J-groove weld joining the nozzle to the head clad surface. The Alloy 600 PWSC CRD nozzle leaks discovered in the fall of 2000 and spring of 2001 in several US plants. Therefore the NRC has recommended a more proactive effort by US utilities to inspect similarly susceptible nozzles in all US plants. The primary safety concern is circumferential cracks that can permit the nozzles to separate from the head at high velocity and produce a large-break leak in the reactor vessel. A secondary concern is head leakage from any through-wall cracks in the nozzle or J-groove weld area. Numerous inspection and repair tools have been developed to address CRD nozzle inspection ...

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 secondary stress ...

Energy Technology Data Exchange (ETDEWEB)

Analyzing various SBLOCA with high pressure safety injection (HPSI) at VVER-440/213, we met a surprising phenomenon - a 'natural' circulation post SG heat transfer reversal. This is not usual, because normal natural circulation (NC) in primary circuit is connected with positive heat transfer at SG. If there is reverse heat transfer at SG (as soon as the break enthalpy outflow is sufficient for removal of reactor decay heat), it should obstruct any natural circulation. The question was, what is the driving force of this 'non-standard natural circulation'. After all we revealed that force - it is the density difference between the colder water in reactor downcomer (cold water from HPSI) and warmer water in inner reactor (lower plenum, core, upper plenum). This phenomenon could be confusing for operating personal, because there would be an opposite temperature difference at the loop than by normal natural circulation (under non-standard NC conditions ...

Energy Technology Data Exchange (ETDEWEB)

Main topic of the project was the manufacturing of highly efficient GaAs-solar cells and the fabrication of concentrator cells. During this process significant progress was made with the material preparation, the solar cell technology and the material and process characterisation. This succeeded in the following efficiencies: - GaAs solar cell made by MOVPE technology: 22.9% on 4 cm{sup 2} (AM1.5g) - GaAs solar cell made by LPE-ER process: 22.8% on 4 cm{sup 2} (AM1.5g) - GaAs concentrator solar cell made by LPE-ER process: 24.9% at C=100xAM1.5d - GaAs concentrator module with fresnel lenses: Module efficiency 20.1% (under irradiation of 793 W/m{sup 2}). Another main focus was the epitaxy of GaAs on Si substrate. Two different approaches were investigated. Together with the cooperation partner ASE, Heilbronn a selective growth technology was developed that led to a decreased crack formation. By a simultanous optimization of the other epitaxy and process parameters, the efficiency was ...

ScienceCinema

...this and ...and ...? and ...and ...and what the ...and such ...also and i would like to ...and that's ...and ...and ...form and most of the time i would like to spend on ...and ...for months on because sixty two and ? one-in-ten and ...and initially model systems and and and ...specifics ? and astrophysics completely ...and ...is seventeen and ...was additionally and ...and ...and and and that's all that's the action and you know all ...and ...and and display ...and responsible ...and what ...paul tsongas and ten and uh and ...and and ...and ...and this is ...and ...and especially ...and ...and ...and know ...and ...and and the activation technique and ...most commonly used and ...of the team to sell the blonde and and and need and ...and ...and ...and that's the whole ...and ...and and ...and ...and something like this and she ...been determined by and ...the plates and ...and ...and ...and ...and ...and ...and ...and and ...and this to dismiss ? ...and ...and i think the people to ...

Energy Technology Data Exchange (ETDEWEB)

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 a new-type of spacer ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Different to the very simple class of homogeneous non-equilibrium models (HEM) an one dimensional thermal-hydraulic theoretical drift-flux based and thus non-homogeneous coolant channel model and, as a result, an in itself complete thermal-hydraulic coolant channel module CCM have been established allowing to simulate in a very general way the steady state and transient behaviour of the most important parameters of a single- or two-phase fluid flowing within any type of heated or non-heated coolant channel (with an eventually varying cross flow area). To avoid mathematical discontinuities at the transition from single- to two-phase flow the coolant channel will, in its general form, be split into different regions, i.e. be looked as a basic channel (BC) which can consist of a number of different flow regimes and can, accordingly, be subdivided into a number of sub-channels (SC-s). All of them belong, obviously, to only two types of SC-s, a SC with an ...