WorldWideScience

Sample records for meltdown

  1. Meltdown reactor core cooling facility

    International Nuclear Information System (INIS)

    Matsuoka, Tsuyoshi.

    1992-01-01

    The meltdown reactor core cooling facility comprises a meltdown reactor core cooling tank, a cooling water storage tank situates at a position higher than the meltdown reactor core cooling tank, an upper pipeline connecting the upper portions of the both of the tanks and a lower pipeline connecting the lower portions of them. Upon occurrence of reactor core meltdown, a high temperature meltdown reactor core is dropped on the cooling tank to partially melt the tank and form a hole, from which cooling water is flown out. Since the water source of the cooling water is the cooling water storage tank, a great amount of cooling water is further dropped and supplied and the reactor core is submerged and cooled by natural convection for a long period of time. Further, when the lump of the meltdown reactor core is small and the perforated hole of the meltdown reactor cooling tank is small, cooling water is boiled by the high temperature lump intruding into the meltdown reactor core cooling tank and blown out from the upper pipeline to the cooling water storage tank to supply cooling water from the lower pipeline to the meltdown reactor core cooling tank. Since it is constituted only with simple static facilities, the facility can be simplified to attain improvement of reliability. (N.H.)

  2. Core-meltdown experimental review

    International Nuclear Information System (INIS)

    1975-08-01

    The results of a study of the experimental evidence having a bearing on hypothetical core meltdowns in light-water reactors are presented. The first objective of the study was to obtain a compendium of the experimental evidence applicable to the analysis of a hypothetical core meltdown. Literature from the nuclear power field and from other scientific disciplines and industrial sources was reviewed. Investigators and other persons knowledgeable in the subject were interviewed. A second objective was to determine what data are required and to determine the adequacy of existing data. In core-meltdown studies only land-based plants have been examined. A third, and final, task of this study was to examine offshore plants to determine applicability of onshore plant analysis to particular areas therein and to determine what information peculiar to meltdown accidents in offshore plants was needed. (U.S.)

  3. Mutational meltdown in laboratory yeast populations

    NARCIS (Netherlands)

    Zeyl, C.; Mizesko, M.; Visser, de J.A.G.M.

    2001-01-01

    In small or repeatedly bottlenecked populations, mutations are expected to accumulate by genetic drift, causing fitness declines. In mutational meltdown models, such fitness declines further reduce population size, thus accelerating additional mutation accumulation and leading to extinction. Because

  4. GLOBAL ECONOMIC MELTDOWN AND THE NIGERIAN ...

    African Journals Online (AJOL)

    global financial meltdown, marked by the collapse of hitherto revered and great financial ... Indeed it is an integral part of a market (capitalist) economy. .... competitively in economic production, so also is the deficit in its trade with the rest of the.

  5. Eigen's Error Threshold and Mutational Meltdown in a Quasispecies Model

    OpenAIRE

    Bagnoli, F.; Bezzi, M.

    1998-01-01

    We introduce a toy model for interacting populations connected by mutations and limited by a shared resource. We study the presence of Eigen's error threshold and mutational meltdown. The phase diagram of the system shows that the extinction of the whole population due to mutational meltdown can occur well before an eventual error threshold transition.

  6. Computer codes developed in FRG to analyse hypothetical meltdown accidents

    International Nuclear Information System (INIS)

    Hassmann, K.; Hosemann, J.P.; Koerber, H.; Reineke, H.

    1978-01-01

    It is the purpose of this paper to give the status of all significant computer codes developed in the core melt-down project which is incorporated in the light water reactor safety research program of the Federal Ministry of Research and Technology. For standard pressurized water reactors, results of some computer codes will be presented, describing the course and the duration of the hypothetical core meltdown accident. (author)

  7. The risk of extinction - the mutational meltdown or the overpopulation

    OpenAIRE

    Malarz, K.

    2006-01-01

    The phase diagrams survival-extinction for the Penna model with parameters: (mutations rate)-(birth rate), (mutation rate)-(harmful mutations threshold), (harmful mutation threshold)-(minimal reproduction age) are presented. The extinction phase may be caused by either mutational meltdown or overpopulation. When the Verhulst factor is responsible for removing only newly born babies and does not act on adults the overpopulation is avoided and only genetic factors may lead to species extinction.

  8. The risk of extinction - the mutational meltdown or the overpopulation.

    Science.gov (United States)

    Malarz, Krzysztof

    2007-04-01

    The phase diagrams survival-extinction for the Penna model with parameters: (mutations rate)-(birth rate), (mutation rate)-(harmful mutations threshold), (harmful mutation threshold)-(minimal reproduction age) are presented. The extinction phase may be caused by either mutational meltdown or overpopulation. When the Verhulst factor is responsible for removing only newly born babies and does not act on adults the overpopulation is avoided and only genetic factors may lead to species extinction.

  9. A Primer on Financial System Meltdown. The Economists' View

    OpenAIRE

    Hahn, Franz R.

    2008-01-01

    Ideologues are quick to explain the current financial meltdown: it's the markets, stupid. Economists agree but add: it's politics too, stupid. Ideologues agree but counter: first and foremost it's capitalism, stupid. Economists agree but reply: §$%&?!, stupid. This is where this short paper takes us: it makes an attempt to give a brief overview of the economists' views on the ongoing financial system crisis explaining "§$%&?!, stupid".

  10. A theory of modern cultural shifts and meltdowns.

    Science.gov (United States)

    Hochberg, Michael E

    2004-08-07

    Many cultural attributes such as adornment, language slang, mannerisms and rituals are thought to have little or no influence on individual survival and reproduction, functioning rather as markers of cultural identity that promote group cohesion. Here, I show that if cultural markers are under weak selection and subject to loss or substitution, then the breakdown of cultural cohesiveness may proceed without stabilizing reactions until many or most of a culture's identifiers are forever lost. This may culminate in a 'cultural meltdown', whereby the culture is caught in a vortex of ever-decreasing membership and insufficient selection against the accumulation of unfamiliar markers. In progressively altering the topology of communication from diffusion to broadcasting, globalization may be both accelerating the erosion of cultural identities and amplifying dominance behaviours above their normal adaptive levels.

  11. Methodological aspects of core meltdown accidents frequency estimates

    International Nuclear Information System (INIS)

    Matthis, P.

    1984-01-01

    A survey is given of the work of the ecological institute relating to models and methods used in the German Risk Study for the assessment of core meltdown accident frequency. A statistical model used by the ecological institute for the estimation of the outage behaviour of components is taken as a comparison, which leads to the conclusion that no appropriate methods for the assessment of component reliability are available to date. Furthermore, there are no secured methods for error propagation computation. The lower limits for the ranges of reliability of components are calculated by approximation. As a result of imperfect modelling and of a number of methodical inaccuracies and neglects, the German Risk Study underestimates the ranges of component reliability by a factor of 3 to 70 (depending on the type of component). (RF) [de

  12. Detonability of containment building atmospheres during core-meltdown accidents

    International Nuclear Information System (INIS)

    Jaung, R.; Berlad, L.; Pratt, W.

    1983-01-01

    During Core-Meltdown Accidents in Light Water Reactors, significant quantities of combustible gases could be released to the containment building. The highest possible peak pressure fields that may occur through combustion processes are associated with detonation phenomena. Accordingly, it is necessary to understand and identify the possible ways in which detonations may or may not occur. Although no comprehensive theory of detonation is currently available, there are useful guidelines, which can be derived from current theoretical concepts and the body of experimental data. This paper examines these guidelines and indicates how they may be used to evaluate the possible occurrence of detonation-related combustion processes. In particular, this study identifies three features that an initiation source must achieve if it is to ultimately result in a stable detonation. One of these features requires post-shock initial conditions that lead to very short ignition delays. This concept is used to examine the possibility of achieving quasi-steady detonation phenomena in nuclear reactor containment buildings during postulated core-melt accidents

  13. COPING WITH GLOBAL MELTDOWN: INDIA’S EXTERNAL SECTOR

    Directory of Open Access Journals (Sweden)

    Nandita Sethi

    2011-07-01

    Full Text Available n 2008 the world economy landed itself in the midst of the most severe financial recession which originated in the developed countries and spread to the developing countries which were hit hard through capital reversals, rising borrowing costs, collapsing world trade and commodity prices, and subsiding remittances. India’s engagement with the global economy became deeper from the 1990s and this made it inevitable to be affected by the global meltdown. This paper attempts to analyze the impact of the global recession on the external sector of the Indian economy. A pre and post recession (2008 analysis is undertaken to see the impact on trade, capital flows, exchange rates and foreign exchange reserves and external debt. The analysis reveals that while India was adversely impacted due to the slowdown in trade, capital flows and outsourcing; the impact has not been as much as in many other Asian economies. The capital flows were soon back, as India seemed like a save haven for funds with reasonable growth and interest rates. The Indian banking and regulatory system has been credited for following prudential norms and India’s huge domestic market and fiscal stimulus have got the economy almost back on track with growth rates looking up again.

  14. Exorcising the nightmare of reactor meltdowns. First of four articles

    International Nuclear Information System (INIS)

    Faltermayer, E.

    1979-01-01

    Facts on the hazards of reactors are investigated in this first article of four on that subject. Some knowledgeable critics warn that a serious nuclear disaster is a real possibility within the next few decades. Other experts, mostly in the nuclear industry, counter that fission power is just another engineering challenge that has been met by a society that copes with many others. Each year, they note, U.S. industry handles enough chlorine to kill the entire human race 100,000 times over. U.S. utilities have accumulated 440 reactor-years of experience with nonbreeeding reactors with no meltdowns. Beginning in 1972, a study (eventually report WASH-1400) was made of hundreds of sequences of things that could go wrong in commercial reactors, including human error, and estimated the amounts of radioactivity that could be released in each sequence under varying weather conditions; the optimistic analyses in that report are well known. In January 1979, the Nuclear Regulatory Commission issued a statement saying that it does not regard as reliable WASH-1400's figures on the overall risk of reactor accidents. In March 1975, some 1,600 electrical cables were burned in a seven-hour fire at Brown's Ferry nuclear plant near Athens, Alabama with no major accident occurring. .The LOFT reactor experiment in Idaho is described. Pipe cracks are the most worrisome problem, but these get discovered and corrected before an accident occurs. In a society that long ago lost its technological innocence, and that lives with far greater hazards both natural and manmade, nuclear power causes more unease that it should

  15. Effects of methodic deficiencies on the quantification of core meltdown frequency

    International Nuclear Information System (INIS)

    Hahn, L.

    1984-01-01

    The application of sequence of events and fault tree analyses for the assessment of the core meltdown frequency raises problems, most of which can be classified under: - Completeness and representativeness of sequences and cuases of events - Modelling of conditional outages (common-mode outages) - Modelling of human behaviour - Reliability data and models. All of the weak points of the German Risk Study related to these problems which are mentioned by the Ecological Institute show a tendency to underestimate the core meltdown frequency by a factor at least 6. (RF) [de

  16. The consequences from liquid pathways after a reactor meltdown accident

    Energy Technology Data Exchange (ETDEWEB)

    Niemczyk, S J; Adams, K G; Murfin, W B; Ritchie, L T; Eppel, E W; Johnson, J D

    1981-06-01

    The potential radiological impact of a core-melt accident on the human population has been investigated. In particular, the radiation dose received from radioactivity which could reach the population via liquid pathways has been considered. Radioactivity could be released directly to the hydrosphere after a core-melt accident as a result of melt-through of the containment basemat followed by any of three processes: (1) leaching of the melt debris; 2 escape of sumpwater through the hole formed by the melt (or from passage out of the containment by an alternate route); and 3) depressurization of the containment atmosphere through the melt hole. The three types of releases would differ primarily in their rates, their magnitudes and their radioactive compositions. Both the containment atmosphere and the sumpwater releases would occur relatively rapidly. However, most of the radionuclides present in these two releases in substantial quantities would be expected to be rather short-lived. Therefore, such releases could have a significant impact at a specific site only if the travel times of the important radionuclides to the human population were small. In contrast, leaching of radionuclides from the melt debris would be expected to occur relatively slowly. Most of the long-lived isotopes would be expected to be found primarily in the melt debris. Consequently, even though this release occurred relatively slowly, the impact could still be significant. In contrast to the situation for releases to the atmosphere, accidents corresponding to the most probable RSS (Reactor Safety Study) meltdown categories would result in the largest releases to the hydrosphere. Furthermore, substantial amounts of radioactivity would generally be expected to be released to the hydrosphere during any meltdown accident involving complete melt-through of the containment basemat. On the basis of subsurface hydrologies alone, sites range from those that essentially preclude any impacts to the human

  17. The consequences from liquid pathways after a reactor meltdown accident

    International Nuclear Information System (INIS)

    Niemczyk, S.J.; Adams, K.G.; Murfin, W.B.; Ritchie, L.T.; Eppel, E.W.; Johnson, J.D.

    1981-06-01

    The potential radiological impact of a core-melt accident on the human population has been investigated. In particular, the radiation dose received from radioactivity which could reach the population via liquid pathways has been considered. Radioactivity could be released directly to the hydrosphere after a core-melt accident as a result of melt-through of the containment basemat followed by any of three processes: (1) leaching of the melt debris; 2 escape of sumpwater through the hole formed by the melt (or from passage out of the containment by an alternate route); and 3) depressurization of the containment atmosphere through the melt hole. The three types of releases would differ primarily in their rates, their magnitudes and their radioactive compositions. Both the containment atmosphere and the sumpwater releases would occur relatively rapidly. However, most of the radionuclides present in these two releases in substantial quantities would be expected to be rather short-lived. Therefore, such releases could have a significant impact at a specific site only if the travel times of the important radionuclides to the human population were small. In contrast, leaching of radionuclides from the melt debris would be expected to occur relatively slowly. Most of the long-lived isotopes would be expected to be found primarily in the melt debris. Consequently, even though this release occurred relatively slowly, the impact could still be significant. In contrast to the situation for releases to the atmosphere, accidents corresponding to the most probable RSS (Reactor Safety Study) meltdown categories would result in the largest releases to the hydrosphere. Furthermore, substantial amounts of radioactivity would generally be expected to be released to the hydrosphere during any meltdown accident involving complete melt-through of the containment basemat. On the basis of subsurface hydrologies alone, sites range from those that essentially preclude any impacts to the human

  18. Lessons from the Russian meltdown : the economics of soft legal constraints

    NARCIS (Netherlands)

    Perotti, E.C.

    2001-01-01

    On August 17, 1998, Russia defaulted on its domestic public debt, declared a moratorium on the private banks foreign liabilities which was equivalent to an outright default, and abandoned its exchange rate regime. The depth of the Russian meltdown shocked the international markets, and precipitated

  19. Lessons from the Russian meltdown : the economics of soft legal constraints

    NARCIS (Netherlands)

    Perotti, E.C.

    2002-01-01

    On August 17, 1998, Russia defaulted on its domestic public debt, declared a moratorium on the private banks foreign liabilities which was equivalent to an outright default, and abandoned its exchange rate regime. The depth of the Russian meltdown shocked the international markets, and precipitated

  20. Why Competent Persons Have Meltdowns Working with Troubled Students: A Personal Essay

    Science.gov (United States)

    Long, Nicholas J.

    2010-01-01

    How do otherwise competent helpers "lose it" in work with certain troubled children and youth? Drawing on extensive research and practice expertise, this article identifies four causes of these predictable professional "meltdowns"--(1) Caught in the Conflict Cycle; (2) Violation of cherished values and beliefs; (3) Tap-in issues; and (4) Carry-in…

  1. Lessons from the Russian meltdown : the economics of soft legal constraints

    NARCIS (Netherlands)

    Perotti, E.C.

    2002-01-01

    On 17 August 1998 Russia abandoned its exchange rate regime, defaulted on its domestic public debt and declared a moratorium on banks' foreign liabilities. This was equivalent to an outright default. The depth and speed of the Russian meltdown shocked the international markets and precipitated a

  2. Aerosol retention during SGTR meltdown sequences under different conditions of tubes vibration

    International Nuclear Information System (INIS)

    Delgado Tardaguila, R.; Herranz, L. E.

    2014-01-01

    The containment bypass of the fission products during SGTR meltdown sequences makes this scenario be a significant risk contributor in PWRs. The EU-SGTR, ARTIST 1 and 2 and the on-going ARTIST-extension programs have investigated the potential attenuation of the source term reaching the secondary side of a failed SG even in the absence of water. (Author)

  3. Analyses of containment loading by hydrogen burning during hypothetical core meltdown accidents

    International Nuclear Information System (INIS)

    Bracht, K.; Tiltmann, M.

    1983-01-01

    The possibility of occurance of violent hydrogen burning during a LWR meltdown accident and its consequences to containment atmosphere conditions are discussed. Two accident sequences with low and high system pressure during the in-vessel-melt phase of a meltdown accident are considered. In both sequences only deflagration, but no detonation may become possible, presuming homogeneity of the containment atmospheres. In a low pressure szenario the pressure increase due to deflagration will not reach the failure pressure of the containment, if combustion takes place when the flammability limit is reached. For the special situation of a rapid release of steam and hydrogen after a high-pressure failure of a reactor pressure vessel, calculations with a multicompartment code show that the possibility for hydrogen burning does not exist. Thus, an additional augmentation of the steam spike as a consequence of the failure of the pressure vessel cannot occur. (orig.)

  4. Evaluation of Effect of Global Economic Meltdown on Capital Market Performance

    Directory of Open Access Journals (Sweden)

    ONAOLAPO ADEKUNLE RAHMAN

    2013-07-01

    Full Text Available The recent financial crisis that loomed the global economy was considered more inclusive than any other period of financial turmoil in the past 60 years. This paper evaluates the implications of the global economic meltdown on the Nigerian Capital Market Performance using the market capitalization of the Nigerian Stock Exchange as a major indicator. When the global economic meltdown came, it poses a recession on the Market Capitalization and the volume of share index of the Nation. This study depends entirely on secondary data in form of annual aggregate time series data of Market capitalization (dependent variable, exchange rate, interest rate, inflation rate, market share index with Dummy variable to represent the period of economic crisis. Ordinary least square of multiple regressions was used to analyze the data into econometric model while F-statistics was used to test for the formulated hypothesis. This study depicts that the global economic meltdown has a negative effect on the Capital Market Performance. It was therefore recommended that the Federal government and the regulatory agencies (CBN, NSE, SEC etc. should come up with intervention and fiscal policies that will suppress these effects and jumpstart the capital market and that the policies should be properly implemented and monitored.

  5. Release of fission products during controlled loss-of-coolant accidents and hypothetical core meltdown accidents

    International Nuclear Information System (INIS)

    Albrecht, H.; Malinauskas, A.P.

    1978-01-01

    A few years ago the Projekt Nukleare Sicherheit joined the United States Nuclear Regulatory Commission in the development of a research program which was designed to investigate fission product release from light water reactor fuel under conditions ranging from spent fuel shipping cask accidents to core meltdown accidents. Three laboratories have been involved in this cooperative effort. At Argonne National Laboratory (ANL), the research effort has focused on noble gas fission product release, whereas at Oak Ridge National Laboratory (ORNL) and at Kernforschungszentrum Karlsruhe (KfK), the studies have emphasized the release of species other than the noble gases. In addition, the ORNL program has been directed toward the development of fission product source terms applicable to analyses of spent fuel shipping cask accidents and controlled loss-of-coolant accidents, and the KfK program has been aimed at providing similar source terms which are characteristic of core meltdown accidents. The ORNL results are presented for fission product release from defected fuel rods into a steam atmosphere over the temperature range 500 to 1200 0 C, and the KfK results for release during core meltdown sequences

  6. Ecological and toxicological aspects of the partial meltdown of the Chernobyl nuclear power plant reactor

    Science.gov (United States)

    Eisler, Ronald; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

    1995-01-01

    the partial meltdown of the 1000-MW reactor at Chernobyl, Ukraine, on April 26, 1986, released large amounts of radiocesium and other radionuclides into the environment, causing widespread radioactive contamination of Europe and the former Soviet Union.1-7 At least 3,000,000 trillion becquerels (TBq) were released from the fuel during the accident (Table 24.1), dwarfing, by orders of magnitude, radiation released from other highly publicized reactor accidents at Windscale (U.K.) and three-Mile Island (U.S.)3,8 The Chernobyl accident happened while a test was being conducted during a normal scheduled shutdown and is attributed mainly to human error.3

  7. Quench cooling of superheated debris beds in containment during LWR core meltdown accidents

    International Nuclear Information System (INIS)

    Ginsberg, T.; Chen, J.C.

    1984-01-01

    Light water reactor core meltdown accident sequence studies suggest that superheated debris beds may settle on the concrete floor beneath the reactor vessel. A model for the heat transfer processes during quench of superheated debris beds cooled by an overlying pool of water has been presented in a prior paper. This paper discusses the coolability of decay-heated debris beds from the standpoint of their transient quench characteristics. It is shown that even though a debris bed configuration may be coolable from the point of view of steady-state decay heat removal, the quench behavior from an initially elevated temperature may lead to bed melting prior to quench of the debris

  8. Study of an hypothetical reactor meltdown accident for a 50 MW sub(th) fast reactor

    International Nuclear Information System (INIS)

    Azevedo, E.M. de.

    1983-01-01

    A melhodology for determining the energy released in hypothetical reactor meltdown accidents is presented. A numerical code was developed based upon the Nicholson method for a uniform and homogeneous reactor with spherical geometry. A comparative study with other know programs in the literature which use better approximations for small energy released, shows that the methodology used were compatible with those under comparison. Besides the influence of some parameters on the energy released, such as the initial power level and the prompt neutron lifetime was studied under this metodology and its result exhibitted. The Doppler effect was also analyzed and its influence on the energy released has been emphasized. (Author) [pt

  9. Containment loadings due to hydrogen burning in LWR core meltdown accidents

    International Nuclear Information System (INIS)

    Cybulskis, P.

    1981-01-01

    The potential pressure loadings due to hydrogen burning under conditions representative of meltdown accident conditions are examined for a variety of PWR and BWR containment designs. For the PWR, the large dry, ice condenser, as well as subatmospheric containments are considered. For the BWR, MARK I, II, and III pressure suppression containments are evaluated. The key factors considered are: free volume, design pressure, extend to hydrogen generation, and the flammability of the atmosphere under a range of accident conditions. The potential for and the possible implications of hydrogen detonation are also considered. The results of these analyses show that the accumulation and rapid burning of the quantities of hydrogen that would be generated during core meltdown accidents will lead to pressures above design levels in all of the containments considered. As would be expected, containments characterized by small volumes and/or low design pressures are the most vulnerable to damage due to hydrogen burning. Large volume, high pressure designs may also be threatened but offer significantly more potential for accomodating hydrogen burns. The attainment of detonable hydrogen mixtures is made easier by smaller containment volumes. Detonable mixtures are also possible in the larger volume containments, but imply the accumulation of hydrogen for long periods of time without prior ignition. Hydrogen detonations, if they occur, would probably challenge the integrity of any of the containments considered. (orig.)

  10. Stability Analysis of the EBR-I Mark-II Core Meltdown Accident

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Jae-Yong; Kang, Chang Mu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    The purpose of this paper is to analyze the stability of the EBR-I core meltdown accident using the NuSTAB code. The result of NuSTAB analysis is compared with previous stability analysis by Sandmeier using the root locus method. The Experimental Breeder Reactor I (EBR-1) at Argonne National Laboratory was designed to demonstrate fast reactor breeding and to prove the use of liquid-metal coolant for power production and reached criticality in August 1951. The EBR-I reactor was undergoing a series of physics experiments and the Mark-II core was melted accidentally on Nov. 29, 1955. The experiment was going to increase core temperature to 500C to see if the reactor loses reactivity, and scram when the power reached 1500 kW or doubling of fission rate per second. However the operator scrammed with a slow moving control and missed the shutdown by two seconds and caused the core meltdown. The NuSTAB code has an advantage of analyzing space-dependent fast reactors and predicting regional oscillations compared to the point kinetics. Also, NuSTAB can be useful when the coupled neutronic-thermal-hydraulic codes cannot be used for stability analysis. Future work includes analyses of the PGSFR for various operating conditions as well as further validation of the NuSTAB calculations against SFR stability experiments when such experiments become available.

  11. Asset Meltdown

    DEFF Research Database (Denmark)

    Marekwica, Marcel; Maurer, Raimond; Sebastian, Steffen P.

    2011-01-01

    Executive Summary. This paper analyzes the relation between demographic structure and real asset returns on Treasury bills, bonds, and stocks for the G7 countries (United States, Canada, Japan, Italy, France, the United Kingdom, and Germany). A macroeconomic multifactor model is used to examine a...

  12. Caesium-rich micro-particles: A window into the meltdown events at the Fukushima Daiichi Nuclear Power Plant

    Science.gov (United States)

    Furuki, Genki; Imoto, Junpei; Ochiai, Asumi; Yamasaki, Shinya; Nanba, Kenji; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C.; Utsunomiya, Satoshi

    2017-02-01

    The nuclear disaster at the Fukushima Daiichi Nuclear Power Plant (FDNPP) in March 2011 caused partial meltdowns of three reactors. During the meltdowns, a type of condensed particle, a caesium-rich micro-particle (CsMP), formed inside the reactors via unknown processes. Here we report the chemical and physical processes of CsMP formation inside the reactors during the meltdowns based on atomic-resolution electron microscopy of CsMPs discovered near the FDNPP. All of the CsMPs (with sizes of 2.0-3.4 μm) comprise SiO2 glass matrices and ~10-nm-sized Zn-Fe-oxide nanoparticles associated with a wide range of Cs concentrations (1.1-19 wt% Cs as Cs2O). Trace amounts of U are also associated with the Zn-Fe oxides. The nano-texture in the CsMPs records multiple reaction-process steps during meltdown in the severe FDNPP accident: Melted fuel (molten core)-concrete interactions (MCCIs), incorporating various airborne fission product nanoparticles, including CsOH and CsCl, proceeded via SiO2 condensation over aggregates of Zn-Fe oxide nanoparticles originating from the failure of the reactor pressure vessels. Still, CsMPs provide a mechanism by which volatile and low-volatility radionuclides such as U can reach the environment and should be considered in the migration model of Cs and radionuclides in the current environment surrounding the FDNPP.

  13. The acute effects of the thermogenic supplement Meltdown on energy expenditure, fat oxidation, and hemodynamic responses in young, healthy males

    Directory of Open Access Journals (Sweden)

    Cooke Matt

    2008-12-01

    Full Text Available Abstract The purpose of this study was to evaluate the effects of a thermogenic supplement, Meltdown, on energy expenditure, fat oxidation, and hemodynamics before and after maximal treadmill exercise. In a double-blind, randomized, placebo-controlled, cross-over design, 12 male participants underwent two testing sessions after consuming either the Meltdown or placebo supplement. While in a fasted state, participants rested for one hour, orally ingested either Meltdown or placebo and rested for another hour, performed a maximal treadmill exercise test, and then rested for another hour. Throughout the testing protocol, resting energy expenditure (REE and respiratory exchange ratio (RER were assessed. In addition, heart rate (HR and blood pressure (BP were assessed before and after exercise. Meltdown increased REE significantly more than placebo at 45 min (1.44 ± 0.25 vs. 1.28 ± 0.23 kcal/min; p = 0.003, 60 min (1.49 ± 0.28 vs. 1.30 ± 0.22 kcal/min; p = 0.025, and 120 min (1.51 ± 0.26 vs. 1.33 ± 0.27 kcals/min; p = 0.014 post-ingestion. Meltdown significantly decreased RER at 30 min (0.84 ± 0.03 vs. 0.91 ± 0.04; p = 0.022 and 45 min post-ingestion (0.82 ± 0.04 vs. 0.89 ± 0.05; p = 0.042, and immediately post-exercise (0.83 ± 0.05 vs. 0.90 ± 0.07; p = 0.009. Furthermore, over the course of the evaluation period, area under the curve assessment demonstrated that REE was significantly increased with Meltdown compared to placebo (992.5 ± 133.1 vs. 895.1 ± 296.1 kcals; p = 0.043, while RER was significantly less than placebo (5.55 ± 0.61 vs. 5.89 ± 0.44; p = 0.002 following ingestion. HR and BP were not significantly affected prior to exercise with either supplement (p > 0.05 and the exercise-induced increases for HR and BP decreased into recovery and were not different between supplements (p > 0.05. These data suggest that Meltdown enhances REE and fat oxidation more than placebo for several hours after ingestion in fully rested and

  14. Safety analysis of a stratified reactor foundation subject to core meltdown

    International Nuclear Information System (INIS)

    Laermann, K.H.; Berhalter, D.; Wieching, G.

    1983-01-01

    Comprehensive calculations were made to examine a foundation plate under static load with non-linear material behaviour. In particular, deformation and crack behaviour of the plate were observed. The calculations hereunder, made to calculate the time of rupture of the plate with the foundation exposed to high temperatures, with and without cavity formation, prove that high temperatures are not as relevant as the melt-down of the layers of armour on top of the middle of the plate. The consequences of this survey are: to protect the top armour of the plate centre and not to use it as support for any structural components. This free space could then be used to instal said multi-layer plate. (orig./HP) [de

  15. Method of reducing the hazard which may occur as a consequence of a reactor core meltdown

    International Nuclear Information System (INIS)

    Donne, M.D.; Dorner, S.; Schumacher, G.

    1978-01-01

    The core melt resulting from a meltdown accident of a GFB, LWR or LMFRR is collected by a core catcher from graphite placed below the core. The core melt is penetrating step by step into a borate store in the collecting vessel and is dissolving in it. Therefore the borate at the same time will absorb the decay heat. In order to remove the solidified and cooled down melted mass water is applied eliminating the borate. The remaining oxide state of the powdery core is sucked off again from the core catcher together with the water. The borate store (e.g. alkali borate) itself consists of separate layers with shaped parts, the coverings of which are made of steel, iron, cast iron, nickel, iron or nickel alloys, ceramic material or glass. (DG) [de

  16. Method of reducing the hazard which may occur as a consequence of a reactor core meltdown

    International Nuclear Information System (INIS)

    Donne, M.D.; Dorner, S.; Schumacher, G.

    1985-01-01

    The core melt resulting from a meltdown accident of a GFB, LWR or LMFRR is collected by a core catcher from graphite placed below the core. The core melt is penetrating step by step into a borate store in the collecting vessel and is dissolving in it. Therefore the borate at the same time will absorb the decay heat. In order to remove the solidified and cooled down melted mass water is applied eliminating the borate. The remaining oxide states of the powdery core is sucked off again from the core catcher together with the water. The borate store (e.g. alkali borate) itself consists of separate layers with shaped parts, the coverings of which are made of steel, iron, cast iron, nickel, iron or nickel alloys, ceramic material or glass. (orig./PW)

  17. Concepts for passive heat removal and filtration systems under core meltdown conditions

    International Nuclear Information System (INIS)

    Wilhelm, J.G.; Neitzel, H.-J.

    1993-01-01

    The objective of the new containment concept being developed by KfK is the complete passive enclosure of a power reactor after a core meltdown accident by means of a solid containment structure and passive removal of the decay heat. This is to be accomplished by cooling the containment walls with ambient air, with thermoconvection as the driving force. The concept of the containment is described. Data are given of the heat removal and the requirements for filtration of the exhaust air, which is contaminated due to the leak rate assumed for the inner containment. The concept for the filter system is described. Various solutions for reduction of the large volumetric flow to be filtered are discussed. 3 refs., 8 figs

  18. A critical experimental study of integral physics parameters in simulated LMFBR meltdown cores

    International Nuclear Information System (INIS)

    Bhattacharyya, S.K.; Wade, D.C.; Bucher, R.G.; Smith, D.M.; McKnight, R.D.; Lesage, L.G.

    1978-01-01

    Integral physics parameters of several representative, idealized meltdown LMFBR configurations were measured in mockup critical assemblies on the ZPR-9 reactor at Argonne National Laboratory. The experiments were designed to provide data for the validation of analytical methods used in the neutronics part of LMFBR accident analysis. Large core distortions were introduced in these experiments (involving 18.5% core volume) and the reactivity worths of configuration changes were determined. The neutronics parameters measured in the various configurations showed large changes upon core distortion. Both diffusion theory and transport theory methods were shown to mispredict the experimental configuration eigenvalues. In addition, diffusion theory methods were shown to result in a non-conservative misprediction of the experimental configuration change worths. (author)

  19. How did Fukushima-Dai-ichi core meltdown change the probability of nuclear accidents?

    International Nuclear Information System (INIS)

    Escobar Rangel, Lina; Leveque, Francois

    2012-10-01

    How to predict the probability of a nuclear accident using past observations? What increase in probability the Fukushima Dai-ichi event does entail? Many models and approaches can be used to answer these questions. Poisson regression as well as Bayesian updating are good candidates. However, they fail to address these issues properly because the independence assumption in which they are based on is violated. We propose a Poisson Exponentially Weighted Moving Average (PEWMA) based in a state-space time series approach to overcome this critical drawback. We find an increase in the risk of a core meltdown accident for the next year in the world by a factor of ten owing to the new major accident that took place in Japan in 2011. (authors)

  20. Quench cooling of superheated debris beds in containment during LWR core meltdown accidents

    International Nuclear Information System (INIS)

    Ginsberg, T.; Chen, J.C.

    1984-01-01

    Light water reactor core meltdown accident sequence studies suggest that superheated debris beds may settle on the concrete floor beneath the reactor vessel. A model for the heat transfer processes during quench (removal of stored energy from initial temperature to saturation temperature) of superheated debris beds cooled by an overlying pool of water has been presented in a prior paper. This paper discusses the coolability of decay-heated debris beds from the standpoint of their transient quench characteristics. It is shown that even though a debris bed configuration may be coolable from the point of view of steady-state decay heat removal, the quench behavior from an initially elevated temperature may lead to bed melting prior to quench of the debris

  1. Dose estimation for nuclear power plant 4 accident in Taiwan at Fukushima nuclear meltdown emission level.

    Science.gov (United States)

    Tang, Mei-Ling; Tsuang, Ben-Jei; Kuo, Pei-Hsuan

    2016-05-01

    An advanced Gaussian trajectory dispersion model is used to evaluate the evacuation zone due to a nuclear meltdown at the Nuclear Power Plant 4 (NPP4) in Taiwan, with the same emission level as that occurred at Fukushima nuclear meltdown (FNM) in 2011. Our study demonstrates that a FNM emission level would pollute 9% of the island's land area with annual effective dose ≥50 mSv using the meteorological data on 11 March 2011 in Taiwan. This high dose area is also called permanent evacuation zone (denoted as PEZ). The PEZ as well as the emergency-planning zone (EPZ) are found to be sensitive to meteorological conditions on the event. In a sunny day under the dominated NE wind conditions, the EPZ can be as far as 100 km with the first 7-day dose ≥20 mSv. Three hundred sixty-five daily events using the meteorological data from 11 March 2011 to 9 March 2012 are evaluated. It is found that the mean land area of Taiwan in becoming the PEZ is 11%. Especially, the probabilities of the northern counties/cities (Keelung, New Taipei, Taipei, Taoyuan, Hsinchu City, Hsinchu County and Ilan County) to be PEZs are high, ranging from 15% in Ilan County to 51% in Keelung City. Note that the total population of the above cities/counties is as high as 10 million people. Moreover, the western valleys of the Central Mountain Range are also found to be probable being PEZs, where all of the reservoirs in western Taiwan are located. For example, the probability can be as high as 3% in the far southern-most tip of Taiwan Island in Pingtung County. This shows that the entire populations in western Taiwan can be at risk due to the shortage of clean water sources under an event at FNM emission level, especially during the NE monsoon period. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  2. Thermal and stress analyses of meltdown cups for LMFBR safety experiments using SLSF in-reactor loops

    International Nuclear Information System (INIS)

    Blomquist, C.A.; Ariman, T.; Pierce, R.D.; Pedersen, D.R.

    1977-01-01

    A description of a meltdown cup to be used in the SLSF in-reactor experiments is presented. Thermal analyses have shown that the cup is capable of containing and cooling the postulated quantities of molten fuel and steel. The basic loadings for stress analyses were defined and failure modes were determined. It was shown that both the maximum bending stress and maximum tangential stress in the Inconel vessel are below the material yield stress. Additionally, the axial stress in the Inconel vessel was found to be negligible. The shear stress in the wire-formed retaining ring is much below the maximum shear stress. Therefore, the meltdown cup is capable of performing its required function

  3. Thermal and stress analyses of meltdown cups for LMFBR safety experiments using SLSF in-reactor loops

    International Nuclear Information System (INIS)

    Blomquist, C.A.; Pierce, R.D.; Pedersen, D.R.; Ariman, T.

    1977-01-01

    The test trains for the Sodium Loop Safety Facility (SLSF) in-reactor experiments, which simulate hypothetical LMFBR accidents, have a meltdown cup to protect the primary containment from the effects of molten materials. Thermal and stress analyses were performed on the cup which is designed to contain 3.6 kg of molten fuel and 2.4 kg of molten steel. Thermal analyses were performed with the Argonne-modified version fo the general heat transfer code THTB, based on the instantaneous addition of 3200 0 K molten fuel with a decay heat of 9 W/gm and 1920 0 K molten steel. These analyses have shown that the cup will adequately cool the molten materials. The stress analysis showed that the Inconel vessel would not fail from the pressure loading, it was also shown that brittle fracture of the tungsten liner from thermal gradients is unlikely. Therefore, the melt-down cup meets the structural design requirements. (Auth.)

  4. Destruction of the BETA experimental facility for core meltdown experiments in the Karlsruhe Nuclear Research Center on 21 March 1992

    International Nuclear Information System (INIS)

    Feige, K.D.

    1992-01-01

    The BETA experiment V 6.2 was intended to yield information on the processes involved in a lateral containment meltdown starting in a concrete wall with external water cooling. The unexpected overpressure that caused the explosion occurred 1896 seconds after the melt had been fed into the crucible, inducing the melt-water interaction. The explosion destroyed only the inner space of the facility. (orig.) [de

  5. Experimental investigations of the meltdown phase of UO2-Zircaloy fuel rods under conditions of failure of emergency cooling

    International Nuclear Information System (INIS)

    Hagen, S.; Mack, A.; Malauschek, H.; Wallenfels, K.

    1975-01-01

    In the monoxidizing helium atmosphere at 1,850 0 C Zircaloy and UO 2 interact violently. The result is a combined meltdown of pellets and can. This phenomenon appears independent of the velocity of temperature rise. In air the oxid skin splits open at 1,890 0 C and the earlier molten material of the interior begins to flow out. When heating up to more than 2,200 0 C the oxid skin remains solid nevertheless. (orig.) [de

  6. Dose estimation for nuclear power plant 4 accident in Taiwan at Fukushima nuclear meltdown emission level

    International Nuclear Information System (INIS)

    Tang, Mei-Ling; Tsuang, Ben-Jei; Kuo, Pei-Hsuan

    2016-01-01

    An advanced Gaussian trajectory dispersion model is used to evaluate the evacuation zone due to a nuclear meltdown at the Nuclear Power Plant 4 (NPP4) in Taiwan, with the same emission level as that occurred at Fukushima nuclear meltdown (FNM) in 2011. Our study demonstrates that a FNM emission level would pollute 9% of the island's land area with annual effective dose ≥50 mSv using the meteorological data on 11 March 2011 in Taiwan. This high dose area is also called permanent evacuation zone (denoted as PEZ). The PEZ as well as the emergency-planning zone (EPZ) are found to be sensitive to meteorological conditions on the event. In a sunny day under the dominated NE wind conditions, the EPZ can be as far as 100 km with the first 7-day dose ≥20 mSv. Three hundred sixty-five daily events using the meteorological data from 11 March 2011 to 9 March 2012 are evaluated. It is found that the mean land area of Taiwan in becoming the PEZ is 11%. Especially, the probabilities of the northern counties/cities (Keelung, New Taipei, Taipei, Taoyuan, Hsinchu City, Hsinchu County and Ilan County) to be PEZs are high, ranging from 15% in Ilan County to 51% in Keelung City. Note that the total population of the above cities/counties is as high as 10 million people. Moreover, the western valleys of the Central Mountain Range are also found to be probable being PEZs, where all of the reservoirs in western Taiwan are located. For example, the probability can be as high as 3% in the far southern-most tip of Taiwan Island in Pingtung County. This shows that the entire populations in western Taiwan can be at risk due to the shortage of clean water sources under an event at FNM emission level, especially during the NE monsoon period. - Highlights: • An advanced Gaussian-type trajectory model to evaluate the evacuation zone at Nuclear Power Plant 4 in Taiwan. • Mean land area of Taiwan in becoming the permanent evacuation zone is 11%. • The probabilities of the northern

  7. Effect of Fuel Structure Materials on Radiation Source Term in Reactor Core Meltdown

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Ha, Kwang Soon

    2014-01-01

    The fission product (Radiation Source) releases from the reactor core into the containment is obligatorily evaluated to guarantee the safety of Nuclear Power Plant (NPP) under the hypothetical accident involving a core meltdown. The initial core inventory is used as a starting point of all radiological consequences and effects on the subsequent results of accident assessment. Hence, a proper evaluation for the inventory can be regarded as one of the most important part over the entire procedure of accident analysis. The inventory of fission products is typically evaluated on the basis of the uranium material (e.g., UO2 and USi2) loaded in nuclear fuel assembly, except for the structure materials such as the end fittings, grids, and some kinds of springs. However, the structure materials are continually activated by the neutrons generated from the nuclear fission, and some nuclides of them (e.g., 14 C and 60 Co) can significantly influence on accident assessment. During the severe core accident, the structure components can be also melted with the melting points of temperature relatively lower than uranium material. A series of the calculation were performed by using ORIGEN-S module in SCALE 6.1 package code system. The total activity in each part of structure materials was specifically analyzed from these calculations. The fission product inventory is generally evaluated based on the uranium materials of fuel only, even though the structure components of the assembly are continually activated by the neutrons generated from the nuclear fission. In this study, the activation calculation of the fuel structure materials was performed for the initial source term assessment in the accident of reactor core meltdown. As a result, the lower end fitting and the upper plenum greatly contribute to the total activity except for the cladding material. The nuclides of 56 Mn, '5 1 Cr, 55 Fe, 58 Co, 54 Mn, and 60 Co are analyzed to mainly effect on the activity. This result

  8. Transport of nuclides during a core meltdown accident, with consideration of filtered venting

    International Nuclear Information System (INIS)

    Haeggblom, H.

    1981-01-01

    A BWR core meltdown accident has been studied with respect to the transport of radioactive and nonactive gases and aerosols. A system consisting of a containment with an outer stone condenser in three parts was considered. Calculations of the aerosol behaviour have been made with the computer programme NAUA and HAARM-3, assuming one single compartment. Results from these calculations have been used for multicompartment calculations with CORRAL II. The code was modified so that particles of different sizes could be considered in the different compartments, and the time dependence of the particles can be arbitrary. In addition to the aerosol transport and deposition, the corresponding quantities for elemental iodine were calculated. It was concluded, that if the total volume of the condenser system is of the order of 10 5 m 3 , practically all elemental iodine and particles can be retained in the system. The only leakage to the environment will be caused by inefficient sealing during the first five hours. The pressure can never damage the condenser. (author)

  9. Sensitivity analysis of thermal hydraulic response in containment at core meltdown accident

    International Nuclear Information System (INIS)

    Kobayashi, Kensuke; Ishigami, Tsutomu; Horii, Hideo; Chiba, Takemi.

    1985-01-01

    A sensitivity analysis of thermal hydraulic response in a containment during a 'station blackout' (the loss of all AC power) accident at Browns Ferry unit one plant was performed with the computer code MARCH 1.0. In the analysis, the plant station batteries were assumed to be available for 4h after the initiation of the accident. The thermal hydraulic response in the containment was calculated by varying several input data for MARCH 1.0 independently and the deviation among calculated results were investigated. The sensitivity analysis showed that (a) the containment would fail due to the overtemperature without any operator actions for plant recovery, which would be strongly dependent on the model of the debris-concrete interaction and the input parameters for specifying the containment failure modes in MARCH 1.0, (b) a core melting temperature and an amount of water left in a primary system at the end of the meltdown were identified as important parameters which influenced the time of the containment failure, and (c) experimental works regarding the parameters mentioned above could be recommended. (author)

  10. DEVELOPMENT AND DEPLOYMENT ASSESSMENT OF A MELT-DOWN PROOF MODULAR MICRO REACTOR (MDP-MMR)

    Energy Technology Data Exchange (ETDEWEB)

    Hawari, Ayman I.; Venneri, Francesco

    2018-04-02

    The objective of this project is to perform feasibility assessment and technology gap analysis and establish a development roadmap for an innovative and highly compact Micro Modular Reactor (MMR) concept that integrates power production, power conversion and electricity generation in a single unit. The MMR is envisioned to use fully ceramic micro-encapsulated (FCM) fuel, a particularly robust form of TRISO fuel, and to be gas-cooled (e.g., He or CO2) and capable of generating power in the range of 10 to 40 MW-thermal. It is designed to be absolutely melt-down proof (MDP) under all circumstances including complete loss of coolant scenarios with no possible release of radioactive material, to be factory produced, to have a cycle length of greater than 20 years, and to be highly proliferation resistant. In addition, it will be transportable, retrievable and suitable for use in remote areas. As such, the MDP-MMR will represent a versatile reactor concept that is suitable for use in various applications including electricity generation, process heat utilization and propulsion.

  11. On the failure modes of alternative containment designs following postulated core meltdown

    International Nuclear Information System (INIS)

    Chan, C.K.; Knee, H.E.; Okrent, D.

    1977-01-01

    The containment response to a postulated core meltdown accident in a PWR ice condenser containment, a BWR Mark III containment and a BWR non-inerted Mark I containment has been examined to see if the WASH-1400 containment failure mode judgement for the Surry large, dry containment and the Peach Bottom Mark I inerted-containment are likely to be appropriate for these alternative containment plant designs. For the PWR, the representative accident chosen for the analysis is a large cold leg break accompanied by a loss of all electric power while the BWR respresentative event chosen is a recirculation line break without adequate core cooling function. Two containment event paths are studied for each of these two cases, depending on whether or not containment vapor suppression function is assumed to be available. Both the core and the containment pressure and temperature response to the accident events are computed for the four time intervals which characterize (a) blowdown of the pipe break, (b) core melt, (c) vessel melt-through, and (d) containment foundation penetration. The calculations are based on a best esimate of the most probable sequence, but certain phenomena and events were followed down multiple tracks. It appears that the non-inerted Mark I containment is not so vulnerable to overpressurization from hydrogen burning as the Mark III; however, acceptable temperatures may be exceeded. (Auth.)

  12. Consequence analysis of core meltdown accidents in liquid metal fast reactor

    International Nuclear Information System (INIS)

    Suk, S.D.; Hahn, D.

    2001-01-01

    Core disruptive accidents have been investigated at Korea Atomic Energy Research Institute(KAERI) as part of work to demonstrate the inherent and ultimate safety of the conceptual design of the Korea Advanced Liquid Metal Reactor(KALIMER), a 150 Mw pool-type sodium cooled prototype fast reactor that uses U-Pu-Zr metallic fuel. In this study, a simple method was developed using a modified Bethe-Tait method to simulate the kinetics and hydraulic behavior of a homogeneous spherical core over the period of the super-prompt critical power excursion induced by the ramp reactivity insertion. Calculations of energy release during excursions in the sodium-voided core of the KALIMER were subsequently performed using the method for various reactivity insertion rates up to 100 $/s, which has been widely considered to be the upper limit of ramp rates due to fuel compaction. Benchmark calculations were made to compare with the results of more detailed analysis for core meltdown energetics of the oxide fuelled fast reactor. A set of parametric studies was also performed to investigate the sensitivity of the results on the various thermodynamics and reactor parameters. (author)

  13. Lack of Critical Slowing Down Suggests that Financial Meltdowns Are Not Critical Transitions, yet Rising Variability Could Signal Systemic Risk

    Science.gov (United States)

    Hoarau, Quentin

    2016-01-01

    Complex systems inspired analysis suggests a hypothesis that financial meltdowns are abrupt critical transitions that occur when the system reaches a tipping point. Theoretical and empirical studies on climatic and ecological dynamical systems have shown that approach to tipping points is preceded by a generic phenomenon called critical slowing down, i.e. an increasingly slow response of the system to perturbations. Therefore, it has been suggested that critical slowing down may be used as an early warning signal of imminent critical transitions. Whether financial markets exhibit critical slowing down prior to meltdowns remains unclear. Here, our analysis reveals that three major US (Dow Jones Index, S&P 500 and NASDAQ) and two European markets (DAX and FTSE) did not exhibit critical slowing down prior to major financial crashes over the last century. However, all markets showed strong trends of rising variability, quantified by time series variance and spectral function at low frequencies, prior to crashes. These results suggest that financial crashes are not critical transitions that occur in the vicinity of a tipping point. Using a simple model, we argue that financial crashes are likely to be stochastic transitions which can occur even when the system is far away from the tipping point. Specifically, we show that a gradually increasing strength of stochastic perturbations may have caused to abrupt transitions in the financial markets. Broadly, our results highlight the importance of stochastically driven abrupt transitions in real world scenarios. Our study offers rising variability as a precursor of financial meltdowns albeit with a limitation that they may signal false alarms. PMID:26761792

  14. Investigation of primary cooling water chemistry following the partial meltdown of Pu-Be neutron source in Tehran Research Reactor Core (TRR)

    Energy Technology Data Exchange (ETDEWEB)

    Aghoyeh, Reza Gholizadeh [School of Research and Development of Nuclear Reactors and Accelerators, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), P.O. Box: 14155-1339, Tehran (Iran, Islamic Republic of); Khalafi, Hossein, E-mail: hkhalafi@aeoi.org.i [School of Research and Development of Nuclear Reactors and Accelerators, Nuclear Science and Technology Research Institute (NSTRI), Atomic Energy Organization of Iran (AEOI), P.O. Box: 14155-1339, Tehran (Iran, Islamic Republic of)

    2011-03-15

    Research highlights: Effect of Pu-Be neutron source meltdown in core on reactor water chemistry. Water chemistry of primary cooling before, during and after of above incident was compared. Training importance. Management of nuclear incident and accident. - Abstract: Effect of Pu-Be neutron source meltdown in core on reactor water chemistry was main aim of this study. Leaving the neutron source in the core after reactor power exceeds a few hundred Watts was the main reason for its partial meltdown. Water chemistry of primary cooling before, during and after of above incident was compared. Activity of some radio-nuclides such as Ba-140, La-140, I-131, I-132, Te-132 and Xe-135 increased. Other radio-nuclides such as Nd-147, Xe-133, Sr-91, I-133 and I-135 are also detected which were not existed before this incident.

  15. Method and device for catching reactor core melt-down masses in hypothetical accidents of nuclear power plants

    International Nuclear Information System (INIS)

    Morlock, G.; Wiesemes, J.; Bachner, D.

    1977-01-01

    The device is to receive the afterheat of the molten core and in this way to prevent afterflow of coolant and a new criticality. A tank below the reactor pressure vessel, with the proper diameter, contains a store of salt or a salt mixture suitable to receive the afterheat of a core melt-down as heat of fusion or conversion. Above the salt, there is a layer of thermoplastics or of a material forming a hardening foam. Coolant eventually continuing to flow out is separated from the core melt by this barrier layer, and thus the build-up of high steam pressures is prevented. Neutron-absorbing materials, like boron salts mixed to the salts, as well as a subdivision of the salt surface, e.g. by means of canalizing firebricks, prevent the formation of new criticality. Further installations within the tank, like pipings or channels, permit the introduction of water after cooling down of the core or salt melt-down mass and to wash out the brine with all radioactive and other constituents for transport to reprocessing or ultimate storage. (HP) [de

  16. Numerical simulation of passive heat removal under severe core meltdown scenario in a sodium cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    David, Dijo K.; Mangarjuna Rao, P., E-mail: pmr@igcar.gov.in; Nashine, B.K.; Selvaraj, P.; Chellapandi, P.

    2015-09-15

    Highlights: • PAHR in SFR under large core relocation to in-vessel core catcher is numerically analyzed. • A 1-D thermal conduction model and a 2-D axisymmetric CFD model are developed for turbulent natural convection phenomenon. • The side pool (cold pool) was found out to be instrumental in storing heat and dissipating it to the heat sink. • Single tray type in-vessel core catcher is found to be thermally effective under one-fourth core relocation. - Abstract: A sequence of highly unlikely events leading to significant meltdown of the Sodium cooled Fast Reactor (SFR) core can cause the failure of reactor vessel if the molten fuel debris settles at the bottom of the reactor main vessel. To prevent this, pool type SFRs are usually provided with an in-vessel core catcher above the bottom wall of the main vessel. The core catcher should collect, retain and passively cool these debris by facilitating decay heat removal by natural convection. In the present work, the heat removal capability of the existing single tray core catcher design has been evaluated numerically by analyzing the transient development of natural convection loops inside SFR pool. A 1-D heat diffusion model and a simplified 2-D axi-symmetric CFD model are developed for the same. Maximum temperature of the core catcher plate evaluated for different core meltdown scenarios using these models showed that there is much higher heat removal potential for single tray in-vessel SFR core catcher compared to the design basis case of melting of 7 subassemblies under total instantaneous blockage of a subassembly. The study also revealed that the side pool of cold sodium plays a significant role in decay heat removal. The maximum debris bed temperature attained during the initial hours of PAHR does not depend much on when the Decay Heat Exchanger (DHX) gets operational, and it substantiates the inherent safety of the system. The present study paves the way for better understanding of the thermal

  17. On-site releases of noble gases and iodine in the event of core meltdown in a swimming pool reactor

    International Nuclear Information System (INIS)

    Montaignac, E. de.

    1976-10-01

    Research aimed at defining a standard model accident for swimming pool type reactors, has led to the adoption to the so-called BORAX accident which involves complete meltdown of the reactor core. This type of accident-an accident related to dimensional problems- is useful for calculations concerning reactor components which have to withstand the mechanical forces resulting from the accident. A study of the radiobiological consequences of this type of accident, involving the entire reactor core, required research to determine as accurately as possible how the iodine, noble gases and solid fission products are distributed between the melted core and the site. The joint document in the annexure served as the basis for discussion at the meeting (BEVS/SESR) on 9th March 1973, at which the SESR set the standard parameter values to be used for estimating fission product distributions on the site. (author)

  18. Numerical investigation on turbulent natural convection in partially connected cylindrical enclosures for analysing SFR safety under core meltdown scenario

    International Nuclear Information System (INIS)

    David, Dijo K.; Mangarjuna Rao, P.; Nashine, B.K.; Selvaraj, P.

    2015-01-01

    Under the unlikely event of severe core meltdown accident in pool type SFR, the molten core materials may rupture the grid plate which supports the fuel subassemblies and it can get relocated in to the lower pool. These debris may eventually settle on the debris collector (i.e., core catcher) installed above the bottom wall of the lower pool. The bed thus formed generates heat due to radioactive decay which has to be passively removed for maintaining the structural integrity of main vessel. By means of natural convection, the heat generated in the debris bed will be transferred to the top pool where the heat sink (i.e., Decay heat exchanger (DHX)) is installed. Heat transfer to the DHX (which is a part of safety grade decay heat removal system) can take place through the opening created in the grid plate which connects the two liquid pools (i.e., the top pool and the lower pool). Heat transfer can also take place through the lateral wall of the lower cylindrical pool to the side pool and eventually to the top pool, and thus to the DHX. This study numerically investigates the effectiveness of heat transfer between lower pool and top pool during PARR by considering them as partially connected cylindrical enclosures. The governing equations have been numerically solved using finite volume method in cylindrical co-ordinates using SIMPLE algorithm. Turbulence has been modeled using k-ω model and the model is validated against benchmark problems of natural convection found in literature. The effect of parameters such as the heat generation rate in the bed and the size of the grid plate opening are evaluated. Also PAHR in SFR pool is modeled using an axi-symmetric model to fund out the influence of grid plate opening on heat removal from core catcher. The results obtained are useful for improving the cooling capability of in-vessel tray type core catcher for handling the whole core meltdown scenarios in SFR. (author)

  19. Analysis of the danger potential of H2/CO-combustion in the event of core meltdown

    International Nuclear Information System (INIS)

    Fischer, M.; Wagler, K.; Schwarzott, W.; Reineke, H.H.

    1987-01-01

    Based on an evaluation of the present state of knowledge and the experiments performed, several computing programs for the simulation of H 2 /CO combustion processes were developed within the scope of this project. Besides the one-compartment-model MOPED, based on the formulation of empirical and phenomenological connections, which was also used later to perform the pressure buildup analyses during various core meltdown (CM) scenarios, these were the first two attempts in respect of a fluid-dynamic description of the combustion processes that also takes the reaction kinetics into account (VERLA code, PISCES code). The analysis of the low (LP) and high (HP) pressure path CM conditions showed that no additional risk arises on the HP path due to potential H 2 combustion. In opposition to this maximum combustion gas fractions of 15% by vol. H 2 and 2.5% by vol. CO with assumption of complete enrichment in the containment result on the LP path. With 37 refs., 3 tabs., 78 figs [de

  20. Thermal and stress analyses of meltdown cups for LMFBR safety experiments using SLSF in-reactor loops

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, C. A. [Argonne National Lab., IL (United States); Ariman, T. [Univ. of Notre Dame, IN (United States); Pierce, R. D.; Pedersen, D. R. [Argonne National Lab., IL (United States)

    1977-07-01

    The test trains for the Sodium Loop Safety Facility (SLSF) in-reactor experiments, which simulate hypothetical LMFBR accidents, have a meltdown cup to protect the primary containment from the effects of molten materials. Thermal and stress analyses were performed on the cup which is designed to contain 3.6 kg of molten fuel and 2.4 kg of molten steel. The cup principal components are: 1. A 38 mm diameter tungsten spike which provides initial fuel quenching and prevents fuel boiling, 2. A 73 mm inside diameter tungsten liner to isolate the support vessel from the molten material high initial temperature, 3. An insulator which is an expedient for extending the experiment time, and 4. An Inconel 625 vessel which provides the structural support to withstand the thermal and pressure stresses. The spike, liner, and insulator are supported by a hemispherical tungsten end cap which fits inside the hemispherical bottom of the support vessel. This vessel is attached to the 316 stainless steel test train with an Inconel 750 wire-formed retaining ring. Thermal analyses were performed with the Argonne-modified version of the general heat transfer code THTB, based on the instantaneous addition of 3200/sup 0/K molten fuel with a decay heat of 9 W/gm and 1920/sup 0/K molten steel. These analyses have shown that the cup will adequately cool the molten materials. The maximum temperature occurs at the center of the fuel region but it is always less than the fuel boiling point. The maximum temperature occurs at the center of the fuel region but it is always less than the fuel boiling point. The most severe heating occurs when there is no sodium flow outside the cup. For this case the sodium boils (approximately 1200/sup 0/K) and the Inconel vessel and tungsten liner temperatures are approximately 1250/sup 0/K and 2420/sup 0/K, respectively.

  1. Reaction- and melting behaviour of LWR-core components UO2, Zircaloy and steel during the meltdown period

    International Nuclear Information System (INIS)

    Hofmann, P.

    1976-07-01

    The reaction behaviour of the UO 2 , Zircaloy-4 and austenitic steel core components was investigated as a function of temperature (till melting temperatures) under inert and oxidizing conditions. Component concentrations varied between that of Corium-A (65 wt.% UO 2 , 18% Zry, 17% steel) and that of Corium-E (35 wt.% UO 2 , 10% Zry, 55% steel). In addition, Zircaloy and stainless steel were used with different degrees of oxidation. The paper describes systematically the phases that arise during heating and melting. The integral composition of the melts and the qualitative as well as quantitative analysis of the phases present in solidified corium are given. In some cases melting points have been determined. The reaction and melting behaviour of the corium specimens strongly depends on the concentration and on the degree of oxidation of the core components. First liquid phases are formed at the Zry-steel interface at about 1,350 0 C. The maximum temperatures of about 2,500 0 C for the complete melting of the corium-specimens are well below the UO 2 melting point. Depending on the steel content and/or degree of oxidation of Zry and steel, a homogeneous metallic or oxide melt or two immiscible melts - one oxide and the other metallic - are obtained. During the melting experiments performed under inert gas conditions the chemical composition of the molten specimens generally change by evaporation losses of single elements, especially of uranium, zirconium and oxygen. The total weight losses go up to 30%; under oxidizing conditions they are substantially smaller due to the occurrence of different phases. In air or water vapor, the occurrence of the phases and the melting behaviour of the core components are strongly influenced by the oxidation rate and the oxygen supply to the surface of the melt. In the case of the hypothetical core melting accident, a heterogeneous melt (oxide and metallic) is probable after the meltdown period. (orig./RW) [de

  2. Study of diluting and absorber materials to control the reactivity during a postulated core meltdown accident in generation IV reactors

    International Nuclear Information System (INIS)

    Plevacova, Kamila

    2010-01-01

    In order to limit the consequences of a hypothetical core meltdown accident in Generation IV Sodium Fast Reactors, absorber materials in or near the core, such as boron carbide B 4 C, and diluting materials in the core catcher will be used to prevent recriticality within the mixture of molten oxide fuel and molten structures called corium. The aim of the PhD thesis was to select materials of both types and to understand their behaviour during their interaction with corium, from chemical and thermodynamic points of view. Concerning B 4 C, thermodynamic calculations and experiments agree with the formation of two immiscible phases at high temperature in the B 4 C - UO 2 system: one oxide and one boride. This separation of phases can reduce the efficiency of the neutrons absorption inside the molten fuel contained in the oxide phase. Moreover, volatilization of a part of the boron element can occur. According to these results, the necessary quantity of B 4 C to be introduced should be reconsidered for postulated severe accident sequence. Other solution could be the use of Eu 2 O 3 or HfO 2 as absorber material. These oxides form a solid solution with the oxide fuel. Concerning the diluting materials, mixed oxides Al 2 O 3 - HfO 2 and Al 2 O 3 - Eu 2 O 3 were preselected. These systems being completely unknown to date at high temperature in association with UO 2 , first points on the corresponding ternary phase diagrams were researched. Contrary to Al 2 O 3 - Eu 2 O 3 - UO 2 system, the Al 2 O 3 - HfO 2 - UO 2 mixture presents only one eutectic and thus only one solidification path which makes easier forecasting the behaviour of corium in the core catcher. (author)

  3. Synthesis of the IRSN report on the topic of water way answers to implement in case of accident with core meltdown occurring on operating pressurized water nuclear reactors

    International Nuclear Information System (INIS)

    2009-06-01

    This report briefly discusses the efficiency of technical measures adopted for the implementation of water ways as answers to an accident with core meltdown in operating pressurized water nuclear reactors. While mentioning the importance of the hydro-geological characteristics of the various sites, the IRSN asks EDF to plan and implement means to prevent any rejection through water ways for some of these sites, to investigate the possibility of building a geotechnical enclosure, to define a storing-control-treatment-rejection chain which would guarantee an efficient management of the water to be pumped, to study retention phenomena for strontium and caesium isotopes in sands and gravels

  4. Thermohydraulic status and component behavior in the PWR during the selected meltdown scenario station blackout (SBO); Thermohydraulisches Verhalten und Komponentenverhalten eines DWR bei ausgewaehltem Kernschmelzszenarium infolge Station Blackout (SBO). Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Band, Sebastian; Blaesius, Christoph; Scheuerer, Martina; Steinroetter, Thomas

    2017-09-15

    The report on the thermohydraulic status and component behavior in the PWR during the selected meltdown scenario station blackout (SBO) includes the following issues: status of science and technology on this topic, analysis of a high-pressure meltdown scenario using ATHLET-CD for a German PWR starting from the initiating event station blackout, three-dimensional computational fluid dynamic (CFD) analyses of the pressurizer coolant loop in a generic German PWR, evaluation of the thermohydraulic steam generator behavior and its effect on the involved primary circuit components.

  5. Evaluation of containment failure modes and fission product releases during core meltdown accidents in a BWR with a Mark III containment

    International Nuclear Information System (INIS)

    Ludewig, H.; Yu, W.S.; Jaung, R.; Pratt, W.T.

    1985-01-01

    An assessment is described of potential failure modes and fission product releases for a large number of postulated core meltdown accidents in a BWR with a Mark III containment. For this containment design, the most important failure mode was found to be due to hydrogen related phenomena. A one-dimensional lumped parameter computer code has been developed and used to determine the probability of various hydrogen phenomena for a range of postulated core meltdown sequences. Potential containment loads have been estimated and compared against the containment capacity to determine the probability of containment failure. The fission product release assessment began by using the MARCH/CORRAL system of codes with key input parameters varied over a reasonable range. The parameters relate to primary system retention, re-emission, pool scrubbing, and fission product release in-vessel vs ex-vessel. The final step used more mechanistic calculations based on the system of codes recently developed under sponsorship of the Accident Source Term Program Office, NRC, and compares these predictions with the range of releases calculated in the sensitivity study

  6. Effect of the dietary supplement Meltdown on catecholamine secretion, markers of lipolysis, and metabolic rate in men and women: a randomized, placebo controlled, cross-over study

    Directory of Open Access Journals (Sweden)

    Fisher-Wellman Kelsey H

    2009-08-01

    Full Text Available Abstract Background We have recently reported that the dietary supplement Meltdown® increases plasma norepinephrine (NE, epinephrine (EPI, glycerol, free fatty acids (FFA, and metabolic rate in men. However, in that investigation measurements ceased at 90 minutes post ingestion, with values for blood borne variables peaking at this time. It was the purpose of the present investigation to extend the time course of measurement to 6 hours, and to include women within the design to determine if sex differences to treatment exist. Methods Ten men (24 ± 4 yrs and 10 women (22 ± 2 yrs ingested Meltdown® or a placebo, using a randomized, cross-over design with one week separating conditions. Blood samples were collected immediately before supplementation and at one hour intervals through 6 hours post ingestion. A standard meal was provided after the hour 3 collection. Samples were assayed for EPI, NE, glycerol, and FFA. Five minute breath samples were collected at each time for measurement of metabolic rate and substrate utilization. Area under the curve (AUC was calculated. Heart rate and blood pressure were recorded at all times. Data were also analyzed using a 2 (sex × 2 (condition × 7 (time repeated measures analysis of variance, with Tukey post hoc testing. Results No sex × condition interactions were noted for AUC for any variable (p > 0.05. Hence, AUC data are collapsed across men and women. AUC was greater for Meltdown® compared to placebo for EPI (367 ± 58 pg·mL-1·6 hr-1 vs. 183 ± 27 pg·mL-1·6 hr-1; p = 0.01, NE (2345 ± 205 pg·mL-1·6 hr-1 vs. 1659 ± 184 pg·mL-1·6 hr-1; p = 0.02, glycerol (79 ± 8 μg·mL-1·6 hr-1 vs. 59 ± 6 μg·mL-1·6 hr-1; p = 0.03, FFA (2.46 ± 0.64 mmol·L-1·6 hr-1 vs. 1.57 ± 0.42 mmol·L-1·6 hr-1; p = 0.05, and kilocalorie expenditure (439 ± 26 kcal·6 hrs-1 vs. 380 ± 14 kcal·6 hrs-1; p = 0.02. No effect was noted for substrate utilization (p = 0.39. Both systolic and diastolic blood pressure

  7. Guidelines and avoiding meltdown

    LENUS (Irish Health Repository)

    Murphy, JFA

    2011-10-01

    The provision of medical care has become more complex and correspondingly more stressful. Patients’ expectations of doctors are high. Poor medical outcomes are in many cases likely to be perceived as physician or surgeon failure rather than the inevitable consequences of the underlying disease. Both the substance and the process of individual cases are closely scrutinised. It is about how you do it as well as what you do.

  8. Meltdown on Long Island

    CERN Document Server

    Lawler, A

    2000-01-01

    The closure of the neutron-scattering facility at Brookhaven after it was discovered that radioactive water had been leaking into the ground for more than a decade, shows what can happen if researchers do not take public feeling seriously (7 p).

  9. Re-assessment of road accident data-analysis policy : applying theory from involuntary, high-consequence, low-probability events like nuclear power plant meltdowns to voluntary, low-consequence, high-probability events like traffic accidents

    Science.gov (United States)

    2002-02-01

    This report examines the literature on involuntary, high-consequence, low-probability (IHL) events like nuclear power plant meltdowns to determine what can be applied to the problem of voluntary, low-consequence high-probability (VLH) events like tra...

  10. Thermogenic effect of meltdown RTD™ energy drink in young healthy women: a double blind, cross-over design study

    Directory of Open Access Journals (Sweden)

    Faigenbaum Avery D

    2009-12-01

    Full Text Available Abstract Background The purpose of this study was to examine the acute metabolic effects of a high-energy drink in healthy, physically-active women. Methods Ten women (20.4 ± 0.70 y; 166.9 ± 7.2 cm; 67.0 ± 7.0 kg; 29.6 ± 6.5% body fat underwent two testing sessions administered in a randomized and double-blind fashion. Subjects reported to the laboratory in a 3-hr post-absorptive state and were provided either 140 ml of the high-energy drink (SUP; commercially marketed as Meltdown RTD™ or placebo (P. Subjects consumed two 70 ml doses of SUP or P, separated by 30 min and rested in a semi-recumbent position for 3 hours. Resting oxygen consumption (VO2 and heart rate (HR were determined every 5 min during the first 30 min and every 10 min during the next 150 min. Blood pressure (BP was determined every 15 min during the first 30 min and every 30 min thereafter. Area under the curve (AUC analysis was computed for VO2, whereas a 3-hour average and hourly averages were calculated for respiratory quotient (RQ, total kcal, HR, BP, and profile of mood states (POMS. Results AUC analysis revealed a 10.8% difference (p = 0.03 in VO2 between SUP and P. No difference in VO2 was seen between the groups in the first hour, but VO2 in SUP was significantly greater than P in the second (13.9%, p = 0.01 and third hours (11.9%, p = 0.03. A difference (p = 0.03 in energy expenditure was seen between SUP (1.09 ± 0.10 kcal·min-1 and P (0.99 ± 0.09 kcal·min-1 for the 3-hour period. Although no difference in energy expenditure was seen in the first hour, significant differences between SUP and P were observed in the second (1.10 ± 0.11 kcal·min-1 and 0.99 ± 0.09 kcal·min-1, respectively; p = 0.02 and third hour (1.08 ± 0.11 kcal·min-1 and 0.99 ± 0.09 kcal·min-1, respectively; p = 0.05. Average systolic BP was significantly higher (p = 0.007 for SUP (110.0 ± 3.9 mmHg compared to P (107.3 ± 4.4 mmHg. No differences were seen in HR, diastolic BP, or POMS

  11. Analysis of recessive sex-linked lethal mutations in genetically different strains of Drosophila melanogaster ms and w irradiated in the five-kilometer zone of the Chernobyl meltdown

    International Nuclear Information System (INIS)

    Aslanyan, M.M.; Kim, A.I.; Magomedova, M.A.; Fatkulbayanova, N.L.

    1994-01-01

    The frequency of induced and spontaneous recessive sex-linked lethal mutations (RSLLM) in Drosophila melanogaster strains w and ms was estimated after their chronic irradiation in the five-kilometer zone of the Chernobyl' meltdown. The mutagenic effect of relatively low radiation doses was analyzed. In an experiment conducted in 1990, a significant increase in the RSLLM frequency was recorded, while, in 1991, no significant difference between the experiment and control was found

  12. Surface analytical investigations of the release behaviour of volatile fission products during simulated core meltdown accidents and of the reaction behaviour of iodine with silver surfaces

    International Nuclear Information System (INIS)

    Moers, H.

    1986-07-01

    The report presents the results of the analysis of aerosol particles formed in simulated laboratory scale core meltdown experiments. In addition the interaction of silver surfaces with gaseous molecular iodine and with iodide and molecular iodine in aqueous solution was investigated. The composition of the aerosol samples and the progress of the reactions mentioned were determined by use of surface analytical techniques (X-ray photoelectron spectroscopy, Auger electron spectroscopy, secondary ion mass spectroscopy). The major information can be evaluated from X-ray photoelectron spectra which exhibit chemical shifts of the photoelectron lines which allowing a discrimination between different chemical species of the same element. The analyses showed that iodine is present in the aerosol particles mainly as caesium iodide and, to a smaller fraction, as silver iodide. During the adsorption of gaseous molecular iodine at metallic silver surfaces a closed silver iodide overlayer is formed. In aqueous iodide solutions one observes chemisorption of the iodide anions up to a coverage of the metallic silver surface of about half a monolayer. Molecular iodine in aqueous solution is completely converted to silver iodide which covers the substrate irregularly. (orig./HP) [de

  13. Iceland's Economic Eruption and Meltdown

    DEFF Research Database (Denmark)

    Nielsson, Ulf; Torfason, Bjarni K.

    2012-01-01

    The Icelandic financial collapse, which occurred in the fall of 2008, is without precedent. Never before in modern history has an entire financial system of a developed country collapsed so dramatically. This paper describes the country's path towards financial liberalisation and the economic...... background that lead to an initially flourishing banking sector. In doing so, the paper elaborates on the economic oversights that were made during the financial build-up of the country and how such mistakes contributed to the crash. The focus is thus on identifying the main factors that contributed...... to the financial collapse and on drawing conclusions about how these missteps could have been avoided. Also summarised are the mistakes that followed in the attempted rescue phase after the disaster had struck. The paper discusses these issues from a general perspective to provide an overview of the pitfalls...

  14. Simulation experiments concerning core meltdown

    International Nuclear Information System (INIS)

    Werle, H.

    1979-01-01

    A gas stream causes a remarkable increase in the interfacial heat flux (by a factor of 8 for v = 0.63 cm/s, v = gas volume flux/horizontal area). The most important characteristics of the system investigated (silicon oil/wood metal) are relatively similar to those of a core melt, Therefore a remarkable increase of the interfacial heat transfer by the gas release may be expected also for a core melt, compared with earlier investigations at the system silicon oil/water the influence of a gas stream is nevertheless remarkably lower for silicon oil/wood metal. This shows that the density ratio plays an important role. (orig./RW) [de

  15. Zimbabwe: Internally or Externally Driven Meltdown

    Science.gov (United States)

    2010-06-01

    front of parliament” were removed by “riot police us[ing] dogs , batons and tear gas.”202 Though the civil society strikes and protests in this period...Mugabe recognized ZAPU’s unwillingness to be muzzled in their opposition of his policies. He then moved to marginalize ZAPU, even in its own home...similar response to other protests, with police breaking up any protests using dogs , batons, or clubs as necessary to disperse protesters whether they

  16. Reconstruction: Meltdown in the Midst of Beauty

    African Journals Online (AJOL)

    denise

    This stir of memory led me to write down my story. ... beauty of courage, time, and deep listening, as examined through the experiences of fear of the new and of my .... Suzy and Marsha, the two studio teachers and long term .... I turn my attention to the video camera and think, ..... Psychology & Psychotherapy, 1(1), 56-64.

  17. The political economy of global finamcial meltdown (Depression ...

    African Journals Online (AJOL)

    It submitted that the global economy was indeed in depression. The implication of mono-economy based on crude oil, purchased only by the west whose economy is shrinking is very dire to the Nigeria it observed. It recommended the adaptation of the Keynesian principles of economic management which involved massive ...

  18. Global economic meltdown and the Nigerian economy | Lawrence ...

    African Journals Online (AJOL)

    International Journal of Development and Management Review ... Other identified causes are the housing bubble and predatory lending by its financial giants. The crisis has inflicted so much harm on the Nigerian economy by resulting in ...

  19. Investigation of activity release during light water reactor core meltdown

    International Nuclear Information System (INIS)

    Albrecht, H.; Matschoss, V.; Wild, H.

    1978-01-01

    A test facility was developed for the determination of activity release and of aerosol characteristics under realistic light water reactor core melting conditions. It is composed of a high-frequency induction furnace, a ThO 2 crucible system, and a collection apparatus consisting of membrane and particulate filters. Thirty-gram samples of a representative core material mixture (corium) were melted under air, argon, or steam at 0.8 to 2.2 bar. In air at 2700 0 C, for example, the relative release was 0.4 to 0.7% for iron, chromium, and cobalt and 4 to 11% for tin, antimony, and manganese. Higher release values of 20 to 40% at lower temperatures (2150 0 C, air) were found for selenium, cadmium, tellurium, and cesium. The size distribution of the aerosol particles was trimodal with maxima at diameters of 0.17, 0.30, and 0.73 μm. The result of a qualitative x-ray microanalysis was that the main elements of the melt were contained in each aerosol particle. Further investigations will include larger melt masses and the additional influence of concrete on the release and aerosol behavior

  20. Release of fission and activation products during LWR core meltdown

    International Nuclear Information System (INIS)

    Albrecht, H.; Matschoss, V.; Wild, H.

    1978-01-01

    Experiments are described by which activity release fractions and aerosol characteristics were investigated for various core melting conditions. Samples of corium and fissium were heated by induction to temperatures of 2800 0 C under air, argon and steam. Release values are presented for Cr, Mn, Fe, Co, Se, Zr, Mo, Cd, Sn, Sb, Te, J, Cs and U. The deposition behaviour of the released products was found to depend strongly on the volatility and on the gas flow rate. Preliminary results of additional measurements indicate that the size distribution of the aerosol particles is trimodal. (author)

  1. How to arrest a core meltdown accident (doing nothing)

    International Nuclear Information System (INIS)

    Baron, Jorge H.

    2000-01-01

    In the eventual situation of a severe accident in a nuclear reactor, the molten core is able to relocate inside the pressure vessel. This may lead to the vessel failure, due to the thermal attack of the molten core (at approximation of 3000K) on the vessel steel wall. The vessel failure implies the failure of a very important barrier that contains the radioactive materials generated during the reactor operation, with a significant risk of producing high radiation doses both on operators and on the public. It is expected, for the new generation of nuclear reactors, that these will be required to withstand (by design) a core melt down accident, without the need for an immediate evacuation of the surrounding population. In this line, the use of a totally passive system is postulated, which fulfills the objective of containing the molten core inside the pressure vessel, at low temperature (approximation 1200K) precluding its failure. The conceptual design of a passive in-vessel core catcher is presented in this paper, built up of zinc, and designed for the CAREM-25 nuclear power plant. (author)

  2. Nuclear snow job: utilities struggle to avoid credibility meltdown

    International Nuclear Information System (INIS)

    Feeney, A.

    1979-01-01

    Electric utilities and the US nuclear industry are criticized for giving a public relations response to safety concerns following the accident at Three Mile Island and for passing the cost of the response on to utility customers. The large amounts of money budgeted by Babcock and Wilcox, Bechtel Power Corporation, the Atomic Industrial Forum, Electric Power Research Institute, Nuclear Energy Women, and others to minimize the incident and counter anti-nuclear arguments with media events are seen here by Feeney as evidence that the utilities and nuclear industry are afraid of political consequences as their technical credibility vanishes

  3. Global economic meltdown and the Nigerian economy | Lawrence ...

    African Journals Online (AJOL)

    International Journal of Development and Management Review. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 5, No 1 (2010) >. Log in or Register to get access to full text downloads.

  4. "Financial Markets Meltdown: What Can We Learn from Minsky"

    OpenAIRE

    L. Randall Wray

    2008-01-01

    In this new Public Policy Brief, Senior Scholar L. Randall Wray explains today's complex and fragile financial system, and how the seeds of crisis were sown by lax oversight, deregulation, and risky innovations such as securitization. He estimates that the combined losses throughout the entire financial sector could amount to several trillion dollars, and that the United States will feel the effects of the crisis for some time - perhaps a decade or more. Wray recommends enhanced oversight of ...

  5. Proposal for computer investigation of LMFBR core meltdown accidents

    International Nuclear Information System (INIS)

    Boudreau, J.E.; Harlow, F.H.; Reed, W.H.; Barnes, J.F.

    1974-01-01

    The environmental consequences of an LMFBR accident involving breach of containment are so severe that such accidents must not be allowed to happen. Present methods for analyzing hypothetical core disruptive accidents like a loss of flow with failure to scram cannot show conclusively that such accidents do not lead to a rupture of the pressure vessel. A major deficiency of present methods is their inability to follow large motions of a molten LMFBR core. Such motions may lead to a secondary supercritical configuration with a subsequent energy release that is sufficient to rupture the pressure vessel. The Los Alamos Scientific Laboratory proposes to develop a computer program for describing the dynamics of hypothetical accidents. This computer program will utilize implicit Eulerian fluid dynamics methods coupled with a time-dependent transport theory description of the neutronic behavior. This program will be capable of following core motions until a stable coolable configuration is reached. Survey calculations of reactor accidents with a variety of initiating events will be performed for reactors under current design to assess the safety of such reactors

  6. A theory of modern cultural shifts and meltdowns.

    OpenAIRE

    Hochberg, Michael E

    2004-01-01

    Many cultural attributes such as adornment, language slang, mannerisms and rituals are thought to have little or no influence on individual survival and reproduction, functioning rather as markers of cultural identity that promote group cohesion. Here, I show that if cultural markers are under weak selection and subject to loss or substitution, then the breakdown of cultural cohesiveness may proceed without stabilizing reactions until many or most of a culture's identifiers are forever lost. ...

  7. Rebranding Nigerian Arts In The Twilight Of Economic Meltdown ...

    African Journals Online (AJOL)

    ... with the emergence of the internet the world suddenly has become a global village and every facet of man's existence suddenly has navigated to the jet age of which every human endeavor that does not catch up with the move is left in the dark, this move has given birth to issues as modernization, globalization, and lately, ...

  8. Globalisation and the Global Economic Meltdown; Prospects and ...

    African Journals Online (AJOL)

    Coming at the heels of the demise of the USSR, globalisation portends the unbridled spread of capitalist tendencies across geographic and ideological boundaries. In Nigeria, globalisation has translated into deregulation and privatisation of public corporations with the attendant lay off of workers. Increased unemployment ...

  9. Core catcher for nuclear reactor core meltdown containment

    International Nuclear Information System (INIS)

    Driscoll, M.J.; Bowman, F.L.

    1978-01-01

    A bed of graphite particles is placed beneath a nuclear reactor core outside the pressure vessel but within the containment building to catch the core debris in the event of failure of the emergency core cooling system. Spray cooling of the debris and graphite particles together with draining and flooding of coolant fluid of the graphite bed is provided to prevent debris slump-through to the bottom of the bed

  10. Measuring the meltdown: drivers of global amphibian extinction and decline.

    Directory of Open Access Journals (Sweden)

    Navjot S Sodhi

    Full Text Available Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545 or had increased (n = 28. These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

  11. Measuring the meltdown: drivers of global amphibian extinction and decline.

    Science.gov (United States)

    Sodhi, Navjot S; Bickford, David; Diesmos, Arvin C; Lee, Tien Ming; Koh, Lian Pin; Brook, Barry W; Sekercioglu, Cagan H; Bradshaw, Corey J A

    2008-02-20

    Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.

  12. Passive decay heat removal by sump cooling after core meltdown

    International Nuclear Information System (INIS)

    Knebel, J.U.; Mueller, U.

    1996-01-01

    This article presents the basic physical phenomena and scaling criteria of decay heat removal from a large coolant pool by single-phase and two-phase natural circulation flow. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of a sump cooling concept for future light water reactors. The sump cooling concept is based on passive safety features within the containment. The work is supported by the German utilities and the Siemens AG. The article gives first measurement results of the 1:20 linearly scaled plane two-dimensional SUCOS-2D test facility. The experimental results of the model geometry are transformed to prototype conditions

  13. Chemical Bank v. WPPSS: a case of judicial meltdown

    International Nuclear Information System (INIS)

    Tamietti, R.L.

    1984-01-01

    The Washington Supreme Court excused Washington cities and public utility districts from their contractual obligation to repay a portion of $2.25 billion in revenue bonds issued to build two cancelled nuclear power plants on the ground that they were take or pay contracts. Because of this ruling, the Washington Public Power Supply System (WPPSS) defaulted on repayment of the bonds in the largest single incident of municipal default in US history. The voided contracts, however, are virtually identical to those used by other large-scale energy projects, raising questions about the financial security of revenue bonds in general. The author outlines the WPPSS history and analyzes the court decision. He criticizes the court's method, and suggests that it deliberately obfuscated the equity and public policy issues upon which the case should have been decided. 153 references

  14. Analysis of the primary source term for meltdown accidents using MELCOR 1.8.2

    International Nuclear Information System (INIS)

    Schmuck, P.

    1995-01-01

    The MELCOR code describing accident phenomena in the core and primary systems was used for source term calculations and - in the context of the MELCOR Cooperative Assessment Programme - for studying two-phase flows through components such as valves and chokes. Results of the latter studies in comparison to experiments gave hints for an improved calculation of momentum transfer between the phases. (orig.)

  15. The Impact of the Economic Meltdown on the Education System of Zimbabwe

    OpenAIRE

    Tichaona Mapolisa; Thembinkosi Tshabalala

    2013-01-01

    The right to education has been enshrined in a number of international treaties and is regarded as a fundamental social, economic and cultural right.  Access to education particularly schooling is a mechanism through which all people can integrate into mainstream society and a means through which they can exercise social, economic and cultural rights.  According to Christies (1991) education produces knowledge, skills, values and attitudes.  It is essential for civic order and citizenship and...

  16. Robust scaling in ecosystems and the meltdown of patch size distributions before extinction

    NARCIS (Netherlands)

    Kefi, S.; Rietkerk, M.; Roy, M.; Franc, A.; Ruiter, de P.C.; Pascual, M.

    2011-01-01

    Robust critical systems are characterized by power laws which occur over a broad range of conditions. Their robust behaviour has been explained by local interactions. While such systems could be widespread in nature, their properties are not well understood. Here, we study three robust critical

  17. Investigation on multilayer failure mechanism of RPV with a high temperature gradient from core meltdown scenario

    Energy Technology Data Exchange (ETDEWEB)

    Jianfeng, Mao, E-mail: jianfeng-mao@163.com [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Remanufacturing, Ministry of Education (China); Xiangqing, Li [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032 (China); Shiyi, Bao, E-mail: bsy@zjut.edu.cn [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Remanufacturing, Ministry of Education (China); Lijia, Luo [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032 (China); Zengliang, Gao [Institute of Process Equipment and Control Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032 (China); Engineering Research Center of Process Equipment and Remanufacturing, Ministry of Education (China)

    2016-12-15

    Highlights: • The multilayer failure mechanism is investigated for RPV under CHF. • Failure time and location of RPV are predicted under various SA scenarios. • The structural behaviors are analyzed in depth for creep and plasticity. • The effect of internal pressure and temperature gradient is considered. • The structural integrity of RPV is secured within the required 72 creep hours. - Abstract: The Fukushima accident shows that in-vessel retention (IVR) of molten core debris has not been appropriately assessed, and a certain pressure (up to 8.0 MPa) still exists inside the reactor pressure vessel (RPV). In the traditional concept of IVR, the pressure is supposed to successfully be released, and the temperature distributed among the wall thickness is assumed to be uniform. However, this concept is seriously challenged by reality of Fukushima accident with regard to the existence of both internal pressure and high temperature gradient. Therefore, in order to make the IVR mitigation strategy succeed, the numerical investigation of the lower head behavior and its failure has been performed for several internal pressures under high temperature gradient. According to some requirements in severe accident (SA) management of RPV, it should be ensured that the IVR mitigation takes effect in preventing the failure of the structure within a period of 72 h. Subsequently, the failure time and location have to be predicted under the critical heat flux (CHF) loading condition for lower head, since the CHF is limit thermal boundary before the melt-through of RPV. In illustrating the so called ‘multilayer failure mechanism’, the structural behaviors of RPV are analyzed in terms of the stress, creep strain, deformation, damage on selected paths.

  18. Forever young: SIRT3 a shield against mitochondrial meltdown, aging, and neurodegeneration

    Directory of Open Access Journals (Sweden)

    Brad eKincaid

    2013-09-01

    Full Text Available Caloric restriction, fasting, and exercise have long been recognized for their neuroprotective and lifespan-extending properties; however, the underlying mechanisms of these phenomena remain elusive. Such extraordinary benefits might be linked to the activation of sirtuins. In mammals, the sirtuin family has seven members (SIRT1-7, which diverge in tissue distribution, subcellular localization, enzymatic activity and targets. SIRT1, SIRT2, and SIRT3 have deacetylase activity. Their dependence on NAD+ directly links their activity to the metabolic status of the cell. High NAD+ levels convey neuroprotective effects, possibly via activation of sirtuin family members. Mitochondrial sirtuin 3 (SIRT3 has received much attention for its role in metabolism and aging. Specific small nucleotide polymorphisms (SNPs in Sirt3 are linked to increased human lifespan. SIRT3 mediates the adaptation of increased energy demand during caloric restriction, fasting and exercise to increased production of energy equivalents. SIRT3 deacetylates and activates mitochondrial enzymes involved in fatty acid β-oxidation, amino acid metabolism, the electron transport chain, and antioxidant defenses. As a result, the mitochondrial energy metabolism increases. In addition, SIRT3 prevents apoptosis by lowering reactive oxygen species (ROS and inhibiting components of the mitochondrial permeability transition pore. Mitochondrial deficits associated with aging and neurodegeneration might therefore be slowed or even prevented by SIRT3 activation. In addition, upregulating SIRT3 activity by dietary supplementation of sirtuin activating compounds might promote the beneficial effects of this enzyme. The goal of this review is to summarize emerging data supporting a neuroprotective action of SIRT3 against Alzheimer’s disease (AD, Huntington’s disease (HD, Parkinson’s disease (PD and amyotrophic lateral sclerosis (ALS.

  19. Spread of fission products after a nuclear melt-down accident

    International Nuclear Information System (INIS)

    Andriesse, C.D.; Tanke, R.H.J.

    1987-01-01

    In this article experimental investigation is described into the spread of fission products within a nuclear power plant, which after an accident involving melting of the nucleus, will be possible in spite of prohibiting constructions for the case of severe unbalancing of generated and carried-off energy. 6 refs.; 4 figs

  20. Experiments on determination and limitation of fission and activation product release during core meltdown

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, H; Krause, W; Wild, H [Kernforschungszentrum Karlsruhe (Germany, F.R.). Inst. fuer Radiochemie; Perinic, D; Kammerer, B; Knauss, H; Mack, A; Stuka, B [Kernforschungszentrum Karlsruhe (Germany, F.R.). Abt. Reaktorbetrieb und Technik; Osborne, M F

    1976-06-01

    In melting experiments with Corium samples of 500 g under air, temperatures of about 2,300/sup 0/C could be reached whereas 500 g samples of Ni could be heated in argon up to only 1,400/sup 0/C. Obviously, the exothermic oxidation reaction of the zircaloy and steel is the reason for that considerable rise of the Corium temperature in air. Using smaller Ni samples (30 g) the maximum HF-power being coupled to the melt material has been determined by measuring the time of constant temperature at the melting point with the generator at full power. The thermal power effectively transmitted to the specimen was only 1.2 KW. Thus, for melting kg-amounts of Corium, a higher generator power is needed as well as a more effective HF-coupling. The rented generator now in use will be replaced, therefore, by a device with a nominal power of 120 KW, and the power transmission to the induction coil will be improved. The first series of release experiments with 30-60 g of Corium will not be affected by these changes. Melting experiments with various steel components (Fe, Cr, Ni) in an argon atmosphere and with Corium under air did not show any selective influence of the vapors on the intensities of the wavelengths used for the temperature measurement. The behavior of a spherical glass vessel above the crucible was quite satisfactory. After melting tests with temperatures of more than 2,700/sup 0/C it was not broken nor did it show any appearance of softening.

  1. Tests on the release of fission and activation products during core meltdown

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, H; Krause, W; Wild, H

    1976-01-01

    The first available results are related to tests in which the release of the main components of the core melt, namely the steel, zircaloy and uranium components, was determined using ThO/sub 2/ crucibles. The release products are dispersed onto the pipe walls of the transport system and the measuring filters which were installed at about 1 m distance from the melt crucibles. Of these, only the precipitates on the filters have been analyzed so far. In the tests under air, the release was clearly dependent on the maximum temperature reached. The release values for Mo and Mn were the highest with 5-10%; uranium with 0.1% on the other hand, was the lowest. In a steam atmosphere over the melt, the analysis of the filter precipitates for all elements gave considerably lower values than with the tests in air.

  2. Global economic meltdown and its effects on human capital development in Nigeria: Lessons and way forward

    Directory of Open Access Journals (Sweden)

    Kehinde Oladele Joseph

    2011-10-01

    Full Text Available Global economies around the world have experienced the most traumatic moments in the last one-decade. The crisis has been described by scholars, as perhaps been the worst financial crisis since the great economic depression of the 1930s. This paper lucidly examines the effects of global economic recession on the development of human capital with reference to Nigeria nation. The objectives of the paper among others are (i To establish the level of the impact of global economic recession on development of skills of human capital in Nigeria (ii To examine if there is any significant relationship between global economic recession and the motivation of human capital development in Nigeria among others. The paper uses survey method with two research hypotheses. Questionnaires were administered among academic staff of two Nigerian universities in the southwest part of Nigeria. Findings showed that the global economic recession has great impact on the development of skills of human capital in Nigeria. Findings also revealed that there exists a positive relationship between global economic recession and training and development of human capital in Nigeria. The paper offers useful policy recommendations, which include the need for government and appropriate agencies to put in place policies such as enabling environment that will lead to the growth and development of human capital in Nigeria. Government needs to put forward policies that minimize cost at all levels, maximize efficiency of output, training and retraining of goods hands; and that there is need to encourage better motivation of workers at every sector of the economy amongst others.

  3. Reactor Meltdown: Critical Zone Processes In Siliciclastics Unlikely To Be Directly Transferable To Carbonates

    Science.gov (United States)

    Gulley, J. D.; Cohen, M. J.; Kramer, M. G.; Martin, J. B.; Graham, W. D.

    2013-12-01

    Carbonate terrains cover 20% of Earth's ice-free land and are modified through interactions between rocks, water and biota that couple ecosystems processes to weathering reactions within the critical zone. Weathering in carbonate systems differs from the Critical Zone Reactor model developed for siliciclastic systems because reactions in siliciclastic critical zones largely consist of incongruent weathering (e.g., feldspar to secondary clay minerals) that typically occur in the soil zone within a few meters of the land surface. These incongruent reactions create regolith, which is removed by physical transport mechanisms that drive landscape denudation. In contrast, carbonate critical zones are mostly composed of homogeneous and soluble minerals, which dissolve congruently with the weathering products exported in solution, limiting regolith in the soil mantle to small amounts of insoluble residues. These reactions can extend to depths greater than 2 km below the surface. As water at the land surface drains preferentially through vertical joints and horizontal bedding planes of the carbonate critical zones, it is 'charged' with biologically-derived carbon dioxide, which decreases pH, dissolves carbonate rock, and enlarges subsurface flowpaths through feedbacks between flow and dissolution. Caves are extreme end products of this process and are key morphological features of carbonate critical zones. Caves link surface processes to the deep subsurface and serve as efficient delivery agents for oxygen, carbon and nutrients to zones within the critical zone that are deficient in all three, interrupting vertical and horizontal chemical gradients that would exist if caves were not present. We present select data from air and water-filled caves in the upper Floridan aquifer, Florida, USA, that demonstrate how caves, acting as very large preferential flow paths, alter processes in carbonate relative to siliciclastic critical zones. While caves represent an extreme end member of hydraulic and chemical heterogeneity that has no direct counterpart siliciclastic systems, these large voids provide easily accessible laboratories to investigate processes in carbonate critical zones, and how they differ from standard siliciclastic models of critical zones.

  4. Iceland's meltdown: the rise and fall of international banking in the North Atlantic

    Directory of Open Access Journals (Sweden)

    Robert H. Wade

    2011-01-01

    Full Text Available This paper shows how rapid privatization and liberalization of Iceland's small local banks around 2000, combined with well-developed crony relations among the elite, enabled a small group of financiers to leverage government-guaranteed deposits into a vast wave of mergers and acquisitions abroad, and redistribute enough of the profits back home to make the economy boom. Negative policy feedback loops were systematically undermined. The incoming left-wing government, with IMF support, has managed to protect the bulk of the population from the worst of the effects.

  5. Metallographic post-test investigations for the scaled core-meltdown-experiments FOREVER-1 and -2

    International Nuclear Information System (INIS)

    Mueller, G.; Boehmert, J.

    2000-08-01

    FOREVER (Failure Of Reactor Vessel Rentention) experiments have been carried out in order to simulate the behaviour the lower head of a reactor pressure vessel under the conditions of a depressurized core melt down scenario. In particular the creep behaviour and the vessel failure mode have been investigated. Metallographic post test investigations have complemented the experimental programme. Samples of different height positions of the vessel of the FOREVER-C1 and -C2 experiments were metallographically examined and characteristic microstructural appearances were identified. Additionally samples with ineffected microstructure were annealed at different temperatures and cooled by different rates and afterwards investigated. In this way the microstructural effects of the temperature regime, the thermomechanical loads and the environmental attack could be characterized. Remarkable effects were characteristic for the FOREVER-C2 experiment where the highest-loaded region below the welding joint reached temperatures of approx. 1100 C and a strong creep damage occurred. In the FOREVER-C1 experiment creep damage could not be observed and the maximum temperature did not exceed 900 C. Environmental attack generated decarburization and oxidation but the effect was restricted to a narrow surface layer. There was almost no chemical interaction between the oxidic melt and the vessel material. (orig.)

  6. Your Guide to Meebo Options: Virtual Reference Summer Meltdown and Fall Shakeout

    Science.gov (United States)

    Breitbach, William

    2012-01-01

    Competition in the virtual reference market got really hot this past summer. Recent developments in virtual reference offerings suggest the market is much more dynamic than most people would have imagined a short time ago. With Google's acquisition of Meebo and its subsequent decision to shut down the chat widget service, many libraries scrambled…

  7. Strategies for surviving the Internet meltdown. The case of two Internet incumbents

    NARCIS (Netherlands)

    Constantinides, Efthymios

    2004-01-01

    This paper reviews a number of theoretical issues dealing with the strategic management process in fast-evolving, uncertain environments and examines the fit between theory and practice by means of two case studies, two successful dot.com incumbents from the first generation of Internet start-ups.

  8. Contamination transfer in the meltdown of a fast reactor. Inverse Leidenfrost phenomenon

    International Nuclear Information System (INIS)

    Eddi, Michel.

    1980-12-01

    Sodium is used as a coolant in so-called breeder reactors. The safety problems encountered with this type of reactor are due to the high power densities dissipated in the medium at high temperatures. The consequences to the plant and the environment of the inability to evacuate such power coupled with a failure in the system used to shut down the reactor has evidently been studied in safety analyses. The reactor must be calculated and built so that the integrity of the containment is guaranteed and no contamination whatsoever observed outside the buildings of the plant. Such a sequence (designated: overall accident) would lead to the melting or vaporization of part of the fuel followed by a violent interaction between the sodium and UO 2 powder. The conditions of this violent interaction (also designated: vapor explosion) are examined in the text. A single or several bubbles containing sodium in two phases, incondensable fission gases (xenon, krypton and argon), fission products together with UO 2 , PuO 2 , steels and structural materials in the form of highly contamined liquid or solid aerosols would then be formed. If the leaktightness of the roof slab was no longer assured (explosive phase), a leak involving sodium and radioactive products would occur. The aim of the work described was to study the behavior of the aerosols present in the reacting medium in order to determine the quantity of contamination transported by the bubble to the roof of the vessel. This quantity will be the source term for a possible pollution outside the vessel [fr

  9. Modeling of BWR core meltdown accidents - for application in the MELRPI. MOD2 computer code

    Energy Technology Data Exchange (ETDEWEB)

    Koh, B R; Kim, S H; Taleyarkhan, R P; Podowski, M Z; Lahey, Jr, R T

    1985-04-01

    This report summarizes improvements and modifications made in the MELRPI computer code. A major difference between this new, updated version of the code, called MELRPI.MOD2, and the one reported previously, concerns the inclusion of a model for the BWR emergency core cooling systems (ECCS). This model and its computer implementation, the ECCRPI subroutine, account for various emergency injection modes, for both intact and rubblized geometries. Other changes to MELRPI deal with an improved model for canister wall oxidation, rubble bed modeling, and numerical integration of system equations. A complete documentation of the entire MELRPI.MOD2 code is also given, including an input guide, list of subroutines, sample input/output and program listing.

  10. Millisecond-Period Meltdown Experiments on Prompt - Burst Effects and Molten-Tin-Water Dropping Experiments

    International Nuclear Information System (INIS)

    Wright, R.W.; Coats, R.L.; Schmidt, T.R.; Arakeri, V.H.

    1976-01-01

    The U.S. Nuclear Regulatory Commission has initiated a program of confirmatory research for the safety assessment of LMFBR plants. In the sodium-fuel interactions area, this research includes a series of real-time in-pile experiments on the pressure and work potential of prompt-burst excursions as well as laboratory dropping experiments with molten tin and water. The in-pile experiments are performed by Sandia Laboratories in the Annular Core Pulse Reactor (ACPR), which has a minimum period of 1.3 milliseconds. These single-pin experiments are performed in a piston-loaded, stagnant-sodium autoclave, that is conceptually similar to the one used in the S-11 TREAT test. Unlike the S-11 test, however, realistic radial temperature profiles are obtained in the fuel, the cladding, and the sodium by pre-pulsing the reactor about 1/2 second before the main pulse. A series of preparatory runs have been made with helium-filled capsules and at low energy with sodium-filled capsules. The first significant fuel-coolant interaction run is scheduled for late March 1976. This will be a double-pulsed run at 2700 j/gm UO 2 . A continuing series of experiments is planned with oxide and advanced fuels in both fresh and irradiated form. In molten-tin-water dropping experiments at UCLA, microsecond duration multi-flash photography has been used for event diagnostics. Transition or nucleate boiling was found to trigger energetic interactions or vapor explosions. Temperature stratification in the water was found to reduce the threshold tin temperature necessary to produce vapor explosions below that the predicted by the coolant homogeneous nucleation hypothesis. Interaction zone growth times of a few msec were measured

  11. Teaching Business Ethics after the Financial Meltdown: Is It Time for Ethics with a Sermon?

    Science.gov (United States)

    Cavaliere, Frank J.; Mulvaney, Toni P.; Swerdlow, Marleen R.

    2010-01-01

    Our country is faced with a financial crisis of mammoth proportions: a crisis rooted in ethics, or rather, the lack of ethics. Critics are increasingly complaining that business schools focus too much teaching effort on maximizing shareholder value, with only a limited understanding of ethical and social aspects of business leadership. Business…

  12. Investigation on multilayer failure mechanism of RPV with a high temperature gradient from core meltdown scenario

    International Nuclear Information System (INIS)

    Jianfeng, Mao; Xiangqing, Li; Shiyi, Bao; Lijia, Luo; Zengliang, Gao

    2016-01-01

    Highlights: • The multilayer failure mechanism is investigated for RPV under CHF. • Failure time and location of RPV are predicted under various SA scenarios. • The structural behaviors are analyzed in depth for creep and plasticity. • The effect of internal pressure and temperature gradient is considered. • The structural integrity of RPV is secured within the required 72 creep hours. - Abstract: The Fukushima accident shows that in-vessel retention (IVR) of molten core debris has not been appropriately assessed, and a certain pressure (up to 8.0 MPa) still exists inside the reactor pressure vessel (RPV). In the traditional concept of IVR, the pressure is supposed to successfully be released, and the temperature distributed among the wall thickness is assumed to be uniform. However, this concept is seriously challenged by reality of Fukushima accident with regard to the existence of both internal pressure and high temperature gradient. Therefore, in order to make the IVR mitigation strategy succeed, the numerical investigation of the lower head behavior and its failure has been performed for several internal pressures under high temperature gradient. According to some requirements in severe accident (SA) management of RPV, it should be ensured that the IVR mitigation takes effect in preventing the failure of the structure within a period of 72 h. Subsequently, the failure time and location have to be predicted under the critical heat flux (CHF) loading condition for lower head, since the CHF is limit thermal boundary before the melt-through of RPV. In illustrating the so called ‘multilayer failure mechanism’, the structural behaviors of RPV are analyzed in terms of the stress, creep strain, deformation, damage on selected paths.

  13. Invasional meltdown in northern lakes: Common carp invasion favors non-native plant species

    Science.gov (United States)

    Disturbances can lead to nonrandom changes in community composition due to interactions between the disturbance and the characteristics of species found in the community or available to colonize, producing both winners and losers of disturbance. When the disturbance is a biologic...

  14. Release of gases and their influence on containment integrity during a hypothetical meltdown accident

    International Nuclear Information System (INIS)

    Hassmann, K.; Reimann, M.

    1981-01-01

    The sequence of a hypothetical core melt down accident has been subdivided into four phases. Heating up of the core until failure of the core support structure is the first phase. It starts at a certain water level in the reactor pressure vessel (RPV) and ends with the failure of the grid plate. The second phase is characterized by the evaporation of the water in the lower plenum of the RPV. The second phase lasts until a molten core debris is formed. The third phase is concerned with the heating up of the pressure vessel after formation of a molten pool in the lower plenum of the RPV. After pressure vessel failure, the molten corium will interact in the fourth phase with the concrete structure beneath the pressure vessel. In this paper the gas release during all four accident phases and the resulting pressure-time history within the containment of a German standard PWR is given, taking into account violent combustion of hydrogen. In particular, the differences caused by dsestruction of concrete with silicious and with calcareous aggregates has been analyzed. The basis for the results in the 4th phase is the WECHSL code. Long term containment calculations have been performed with the COCMEL-code

  15. Development of CHF models for inner and outer RPV gaps in a meltdown severe accident

    International Nuclear Information System (INIS)

    Wang, J.; Tian, W.X.; Feng, K.; Yu, H.X.; Zhang, Y.P.; Su, G.H.; Qiu, S.Z.

    2013-01-01

    Highlights: • A CHF model was developed to predict the CHF in hemispherical narrow gap. • The computed result was validated by the test data of Park and Köhler. • An analytical CHF model was developed to predict the CHF on the outer surface of the lower head. • The predicted CHF was compared with the experimental data of ULPU-V. • Two CHF models developed for the inner and outer CHF predict the CHF well. - Abstract: During a severe accident, the core melt relocates in the lower head and a hemispherical narrow gap may appear between the crust and the lower head because of the different material expansion ratio. The existence of this gap is very important to the integrity of the lower head. Based on the counter current flow limitation (CCFL) between the vapor phase and the liquid phase, a CHF model was developed to predict the CHF in hemispherical narrow gap. The CHF model developed was validated by the test data of Park and Köhler. The effect of key parameters, including the system pressure, radius of melt, and gap size, on the CHF were investigated. And the TMI-2 accident was also calculated by using the CHF formula. Moreover, based on the interface separation model, an analytical CHF model was developed to predict the CHF on the outer surface of the lower head. The predicted CHF was compared with the experimental data of ULPU-V. It indicated that the CHF models developed for the inner and outer CHF could predict the CHF well

  16. Belowground legacies of Pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown.

    Science.gov (United States)

    Dickie, Ian A; St John, Mark G; Yeates, Gregor W; Morse, Chris W; Bonner, Karen I; Orwin, Kate; Peltzer, Duane A

    2014-01-01

    Plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. These effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. We used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal legacy caused by invasion of the non-native tree Pinus contorta into a native plant community. Pinus facilitated ectomycorrhizal infection of the co-occurring invasive tree, Pseudotsuga menziesii, but not conspecific Pinus (which always had ectomycorrhizas) nor the native pioneer Kunzea ericoides (which never had ectomycorrhizas). Pinus also caused a major shift in soil nutrient cycling as indicated by increased bacterial dominance, NO3-N (17-fold increase) and available phosphorus (3.2-fold increase) in soils, which in turn promoted increased growth of graminoids. These results parallel field observations, where Pinus removal is associated with invasion by non-native grasses and herbs, and suggest that legacies of Pinus on soil nutrient cycling thus indirectly promote invasion of other non-native plant species. Our findings demonstrate that multi-trophic belowground legacies are an important but hitherto largely unconsidered factor in plant community reassembly following invasive plant removal. Published by Oxford University Press on behalf of the Annals of Botany Company.

  17. Insider Information, the Bane of Financial Melt-Down? (Pp. 111-121)

    African Journals Online (AJOL)

    User

    management and reduce agency costs is another option (Cook and Easter ... managers or other stakeholders) which makes for a firm's future (Fama and. Jensen, 1985). .... Collateralized debt obligations and credit derivatives (unlike publicly ...

  18. How to arrest a core meltdown accident (doing nothing); Como detener un accidente con fusion de nucleo (sin hacer nada)

    Energy Technology Data Exchange (ETDEWEB)

    Baron, Jorge H [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina)

    2000-07-01

    In the eventual situation of a severe accident in a nuclear reactor, the molten core is able to relocate inside the pressure vessel. This may lead to the vessel failure, due to the thermal attack of the molten core (at approximation of 3000K) on the vessel steel wall. The vessel failure implies the failure of a very important barrier that contains the radioactive materials generated during the reactor operation, with a significant risk of producing high radiation doses both on operators and on the public. It is expected, for the new generation of nuclear reactors, that these will be required to withstand (by design) a core melt down accident, without the need for an immediate evacuation of the surrounding population. In this line, the use of a totally passive system is postulated, which fulfills the objective of containing the molten core inside the pressure vessel, at low temperature (approximation 1200K) precluding its failure. The conceptual design of a passive in-vessel core catcher is presented in this paper, built up of zinc, and designed for the CAREM-25 nuclear power plant. (author)

  19. An improved Zircaloy-steam reaction model for use with the March 2 (Meltdown Accident Response Characteristics) code

    International Nuclear Information System (INIS)

    Manahan, M.P.

    1983-01-01

    An improved Zircaloy-steam oxidation reaction model has been incorporated into the MARCH 2 code which includes: (1) improved physical modeling for solid-state process oxidation, (2) improved geometric modeling for gaseous diffusion oxidation, (3) chemisorption/dissociation retardation due to high hydrogen partial pressures, and (4) laminar and turbulent flow conditions. Several accident sequences have been analyzed using the model, and for the sequences considered, the results indicate that the integrated and averaged variables are not significantly altered for the current level of fuel modeling, however, the localized variables such as nodal temperature and oxide thickness are affected

  20. Computing and the Crisis: The Significant Role of New Information Technologies in the Current Socio-economic Meltdown

    Directory of Open Access Journals (Sweden)

    David Hakken

    2010-08-01

    Full Text Available There is good reason to be concerned about the long-term implications of the current crisis for the reproduction of contemporary social formations. Thus there is an urgent need to understand it character, especially its distinctive features. This article identifies profound ambiguities in valuing assets as new and key economic features of this crisis, ambiguities traceable to the dominant, “computationalist” computing used to develop new financial instruments. After some preliminaries, the article identifies four specific ways in which computerization of finance is generative of crisis. It then demonstrates how computationalist computing is linked to other efforts to extend commodification based on the ideology of so-called “intellectual property” (IP. Several other accounts for the crisis are considered and then demonstrated to have less explanatory value. After considering how some commons-oriented (e.g., Free/Libre and/or Opening Source Software development projects forms of computing also undermine the IP project, the article concludes with a brief discussion of what research on Socially Robust and Enduring Computing might contribute to fostering alternative, non-crisis generative ways to compute.

  1. "Anonymous Meltdown": Content Themes Emerging in a Nonfacilitated, Peer-only, Unstructured, Asynchronous Online Support Group for Family Caregivers.

    Science.gov (United States)

    Diefenbeck, Cynthia A; Klemm, Paula R; Hayes, Evelyn R

    2017-12-01

    By providing care for loved ones in the home, family caregivers save millions of dollars for our overtaxed healthcare system. Support groups can lighten the psychological burden of caregiving. Nonprofessionally facilitated (or peer) online caregiver support groups can help meet a critical need in healthcare as a low-cost resource for caregivers. Online caregiver peer support groups can promote the health and well-being of family caregivers and, by extension, the patients themselves, resulting in cost-savings for society. A better understanding of these types of groups is of critical importance, given the unrelenting pace of demographic shift in the United States. The purpose of this study was to examine content themes emerging from an unstructured, asynchronous online peer support group for family caregivers of people with chronic illness. Qualitative content analysis was used, yielding six themes: "experiencing the emotional toll," "need for catharsis/venting," "finding the silver linings," "seeking specific advice/problem solving," "realizing home is no longer a haven," and "adapting to the caregiver role." The themes reflect what emerged organically in an online support group that was not professionally facilitated or structured in any way. Heterogeneity in the relationship between caregivers and care recipients may negatively affect outcomes and requires further study.

  2. Millisecond-period meltdown experiments on prompt-burst effects and molten-tin-water dropping experiments

    International Nuclear Information System (INIS)

    Wright, R.W.; Coats, R.L.; Schmidt, T.R.; Arakeri, V.H.

    1976-01-01

    The U.S. Nuclear Regulatory Commission has initiated a program of confirmatory research for the safety assessment of LMFBR plants. In the sodium-fuel interactions area, this research includes a series of real-time in-pile experiments on the pressure and work potential of prompt-burst excursions as well as laboratory dropping experiments with molten tin and water. The in-pile experiments are performed by Sandia Laboratories in the Annular Core Pulse Reactor (ACPR), which has a minimum period of 1.3 milliseconds. These single-pin experiments are performed in a piston-loaded, stagnent-sodium autoclave, that is conceptually similar to the one used in the S-11 TREAT test. Unlike the S-11 test, however, realistic radial temperature profiles are obtained in the fuel, the cladding, and the sodium by pre-pulsing the reactor about 1/2 second before the main pulse. A series of preparatory runs have been made with helium-filled capsules and at low energy with sodium-filled capsules. The first significant fuel-coolant interaction run is scheduled for late March 1976. This will be a double-pulsed run at 2700 j/gm UO 2 . A continuing series of experiments is planned with oxide and advanced fuels in both fresh and irradiated form. In molten-tin-water dropping experiments at UCLA, microsecond duration multi-flash photography has been used for event diagnostics. Transition or nucleate boiling was found to trigger energetic interactions or vapor explosions. Temperature stratification in the water was found to reduce the threshold tin temperature necessary to produce vapor explosions below that the predicted by the coolant homogeneous nucleation hypothesis. Interaction zone growth times of a few msec. were measured. (auth.)

  3. Experimental investigation on the effect of the tube vibration on the aerosol retention during SGTR meltdown sequences

    International Nuclear Information System (INIS)

    Tardaguila, R. D.; Herranz, L. E.

    2013-01-01

    In PWRs Steam Generator Tube Rupture (SGTR) severe accident sequences scenario, with containment bypass, may become a significant contribution to the NPP risk. Since last two decades the EU-SGTR, ARTIST 1 and 2 and the on-going ARTIST-extension programs have investigated the potential attenuation of the source term in these accidental sequences. Thanks to them, it has been identified key factors that could influence on the source term attenuation as the tube vibration. This paper presents the results of the Phenomenon Test (PT) campaign, focused on the vibration influence on the mass retention on the break stage of a SG and the characterization of the tubes vibration.

  4. Analysis of the primary source term for meltdown accidents using MELCOR 1.8.2; Analyse des primaeren Quellterms bei Kernschmelzunfaellen mit MELCOR 1.8.2

    Energy Technology Data Exchange (ETDEWEB)

    Schmuck, P.

    1995-08-01

    The MELCOR code describing accident phenomena in the core and primary systems was used for source term calculations and - in the context of the MELCOR Cooperative Assessment Programme - for studying two-phase flows through components such as valves and chokes. Results of the latter studies in comparison to experiments gave hints for an improved calculation of momentum transfer between the phases. (orig.)

  5. Software concepts for the build-up of complex systems - selection and realization taking as example a program system for calculation of hypothetical core meltdown accidents

    International Nuclear Information System (INIS)

    Scheuermann, W.

    1994-10-01

    Development and application of simulation systems for the analysis of complex processes require on the one hand and detailed engineering knowledge of the plant and the processes to be simulated and on the other hand a detailled knowledge about software engineering, numerics and data structures. The cooperation of specialists of both areas will become easier if it is possible to reduce the complexicity of the problems to be solved in a way that the analyses will not be disturbed and the communication between different disciplines will not become unnecessarily complicated. One solution to reduce the complexity is to consider computer science as an engineering discipline which provides mainly abstract elements and to allow engineers to build application systems based on these abstract elements. The principle of abstraction leads through the processes of modularisation and the solution of the interface problem to an almost problem independent system architecture where the elements of the system (modules, model components and models) operate only on those data assigned to them. In addition the development of abstract data types allows the formal description of the relations and interactions between system elements. This work describes how these ideas can be concretized to build complex systems which allow reliable and effective problem solutions. These ideas were applied successfully during the design, realization and application of the code system KESS, which allows the analysis of core melt down accidents in pressurized water reactors. (orig.) [de

  6. The Glaring Socioeconomic Meltdown in Post-Soviet Ukraine, Moldova, and Belarus: A Distorted Mindset in Search of a Way Out

    Directory of Open Access Journals (Sweden)

    Olesea Ghedrovici

    2013-07-01

    Full Text Available Cultural and historical values and assumptions deeply imprint all aspects of people’s lives, including their role in social, economic, and political transformation. Many of the former Soviet states are still going through a painful metamorphosis on a confusing path toward acceptance of freedom and democratic values. The idea we wish to highlight there is the impact of the Soviet moral and psychological legacy on the socioeconomic transition now under way in the East European countries that once were republics of the Soviet Union. It is important to shed light on the reasons why, after 20 years of formal independence, the region is still struggling to find its way forward.

  7. Investigation of surface deposition pertaining to the calculation of the deposition of aerosols released in core-meltdown accidents in power reactors

    International Nuclear Information System (INIS)

    Roed, J.

    1981-10-01

    Deposition of fall-out particles of cesium-137 on vertical building surfaces has been measured. The deposition is combined with the corresponding concentration in air of fall-out particles to give the dry deposition velocity. The dry deposition velocity on plane collectors like building surfaces, plane bare soil, roads, etc. is compared to the velocity on rough surfaces like grass, clover, etc. This is done on the basis of our own measurements and the relevant literature. (author)

  8. Reactor safety study. An assessment of accident risks in U. S. commercial nuclear power plants. Appendices VII, VIII, IX, and X. [PWR and BWR

    Energy Technology Data Exchange (ETDEWEB)

    1975-10-01

    Information is presented concerning the release of radioactivity in reactor accidents; physical processes in reactor meltdown accidents; safety design rationale for nuclear power plants; and design adequacy.

  9. Reactor safety study. An assessment of accident risks in U.S. commercial nuclear power plants. Appendices VII, VIII, IX, and X

    International Nuclear Information System (INIS)

    1975-10-01

    Information is presented concerning the release of radioactivity in reactor accidents; physical processes in reactor meltdown accidents; safety design rationale for nuclear power plants; and design adequacy

  10. The Three Mile Island Disaster.

    Science.gov (United States)

    Crosby, Emeral

    1980-01-01

    For the past decade, education has been experiencing meltdown, explosions, radiation leaks, heat pollution, and management crises, just like the Three Mile Island disaster. This article offers suggestions on how to deal with these problems. (Author/LD)

  11. Oxidation during reflood of reactor core with melting cladding

    Energy Technology Data Exchange (ETDEWEB)

    Siefken, L.J.; Allison, C.M.; Davis, K.L. [and others

    1995-09-01

    Models were recently developed and incorporated into the SCDAP/RELAP5 code for calculating the oxidation of fuel rods during cladding meltdown and reflood. Experiments have shown that a period of intense oxidation may occur when a hot partially oxidized reactor core is reflooded. This paper offers an explanation of the cladding meltdown and oxidation processes that cause this intense period of oxidation. Models for the cladding meltdown and oxidation processes are developed. The models are assessed by simulating a severe fuel damage experiment that involved reflood. The models for cladding meltdown and oxidation were found to improve calculation of the temperature and oxidation of fuel rods during the period in which hot fuel rods are reflooded.

  12. Severe accident considerations for modern KWU-PWR plants

    International Nuclear Information System (INIS)

    Eyink, J.

    1987-01-01

    In assumption of severe accident on modern KWU-PWR plants the author discusses on the: selection of core meltdown sequences, course of the accident, containment behaviour and source terms for fission products release to the environment

  13. The role of 'financial myths' in financial crises

    OpenAIRE

    Eric S. Rosengren

    2011-01-01

    Remarks by Eric S. Rosengren, President and Chief Executive Officer, Federal Reserve Bank of Boston, at the Boston University conference on The State of Financial Reform (panel on Lessons Learned from the Global Financial Meltdown), February 28, 2011, Boston, Massachusetts

  14. Three Mile Island Accident Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Three Mile Island Accident Data consists of mostly upper air and wind observations immediately following the nuclear meltdown occurring on March 28, 1979, near...

  15. Nuclear reactor core catcher

    International Nuclear Information System (INIS)

    1977-01-01

    A nuclear reactor core catcher is described for containing debris resulting from an accident causing core meltdown and which incorporates a method of cooling the debris by the circulation of a liquid coolant. (U.K.)

  16. Uus plaat

    Index Scriptorium Estoniae

    2004-01-01

    Uutest plaatidest "Zuccero", Lanny Kravitz "Baptism", Alanis Morissette "So-Called Chaos", ABBA "The ABBA Story", Ash "Meltdown", Alya "They Died for Beuty", "Cafe del Moar. The Best of Jose Padilla, "Blue Note Revisited", Dingo "Dingomania"

  17. Annual meeting on nuclear technology 1982. Technical meeting: Possibilities and effects of serious reactor accidents

    International Nuclear Information System (INIS)

    1982-01-01

    A critical examination of the forecast of a design basis accident, the view of the Sandia National Laboratory on the probability of a steam explosion after a core meltdown accident is comparison with WASH-1400, the possibilities of interactions with the containment structure and fission product release, as well as the influences for the assessment of risk in Germany taken from the analysis of core meltdown accidents are dealt with in these papers. (DG) [de

  18. Research work for improving LWR safety

    International Nuclear Information System (INIS)

    Bork, G.

    1993-09-01

    The work performed in 1992 for the PSF project centers on various phenomena of severe fuel damage and on selected aspects of a core meltdown accident, relating to aerosol behaviour and filter engineering, and to methods of assessing and minimizing the radiological impacts of a reactor accident. The 1992 task programme of the project included research into extreme load conditions affecting the containment in a core meltdown accident: first results are given of the experiments performed. (orig./HP) [de

  19. German risk study nuclear power plants, phase B

    International Nuclear Information System (INIS)

    1990-01-01

    The book documents the results of the probabilistic safety analysis performed at the Biblis-B reference plant. It covers 1) result course analyses and reliability analyses of loss of coolant accidents and transients without and with regard to on-site emergency measures; 2) event tree analyses of on-site and off-site events; 3) analyses of the function of the safety tank in the case of core meltdown accidents, and of the release of fission products into the environment in such case. The probability of a core meltdown is about 3-4 to 100,000 per year and plant. (HP) [de

  20. Assessment of uncertainties in core melt phenomenology and their impact on risk at the Z/IP facilities

    International Nuclear Information System (INIS)

    Pratt, W.T.; Ludewig, H.; Bari, R.A.; Meyer, J.F.

    1983-01-01

    An evaluation of core meltdown accidents in the Z/IP facilities has been performed. Containment event trees have been developed to relate the progression of a given accident to various potential containment building failure modes. An extensive uncertainty analysis related to core melt phenomenology has been performed. A major conclusion of the study is that large variations in parameters associated with major phenomenological uncertainties have a relatively minor impact on risk when external initiators are considered. This is due to the inherent capability fo the Z/IP containment buildings to contain a wide range of core meltdown accidents. 12 references, 2 tables

  1. ASTRID core: Design objectives, design approach, and R&D in support

    International Nuclear Information System (INIS)

    Mignot, G.; Devictor, N.

    2012-01-01

    ASTRID core design is mainly guided by safety objectives: 1. Prevention of the core meltdown accident: To prevent meltdown accidents: - by a natural behavior of the core and the reactor (no actuation of the two shutdown systems); - with adding passive complementary systems if natural behavior is not sufficient for some transient cases. 2. Mitigation of the fusion accident: To garantee that core fusion accidents don’t lead to significant mechanical energy release, whatever initiator event: - by a natural core behavior; - with adding specific mitigation dispositions in case of natural behavior is not suffficient

  2. Thermal conditions and functional requirements for molten fuel containment

    International Nuclear Information System (INIS)

    Kang, C.S.; Torri, A.

    1980-05-01

    This paper discusses the configuration and functional requirements for the molten fuel containment system (MFCS) in the GCFR demonstration plant design. Meltdown conditions following a loss of shutdown cooling (LOSC) accident were studied to define the core debris volume for a realistic meltdown case. Materials and thicknesses of the molten fuel container were defined. Stainless steel was chosen as the sacrificial material and magnesium oxide was chosen as the crucible material. Thermal conditions for an expected quasi-steady state were analyzed. Highlights of the functional requirements which directly affect the MFCS design are discussed

  3. Research work for improving LWR safety. 1991 annual report

    International Nuclear Information System (INIS)

    1992-08-01

    The work performed in 1991 for the PNS project centers on various phenomena of severe fuel damage and on selected aspects of a core meltdown accident, relating to aerosol behaviour and filter engineering, and to methods of assessing and minimizing the radiological impacts of a reactor accident. One paper included in this annual report summarizes the evaluation of experiments carried out in 1990 at the Wuerenlingen PROTEUS reactor. The 1991 task programme of the project for the first time included research into extreme load conditions affecting the containment in a core meltdown accident; first results are given of the experiments performed. (orig./DG) [de

  4. Hydrogen transport in the containment; Wasserstofftransport im Containment

    Energy Technology Data Exchange (ETDEWEB)

    Royl, P.; Mueller, C.; Travis, J.R.; Wilson, T.

    1995-08-01

    For the description of transport phenomena in water vapor/hydrogen mixtures released in nuclear meltdown accidents, an integrated analytical model is being developed for LWR containments. Thermal and mechanical loads due to recombination and combustion are to be calculable. The 3-dimensional GASFLOW code was taken over from LANL in exchange for HDR experimental results and Battelle BMC program results. (orig.)

  5. Keynesian, Monetarist and Supply-Side Policies: An Old Debate Gets New Life

    Science.gov (United States)

    Niederjohn, M. Scott; Wood, William C.

    2009-01-01

    Debates over how to promote a healthy economy are pervasive once more, after decades when it seemed such debates had been put to rest. The market meltdown of 2008 ended a long string of years in which monetary policy reigned supreme. Monetary policy is the regulation of money and the banking system to influence economic variables. Its adherents,…

  6. The Cost of Social Relations Oversight in the Adaptive Appropriation of Japanese Management Practices

    DEFF Research Database (Denmark)

    Tackney, Charles T.

    2006-01-01

    In 1998, a late July settlement of the Flint, Michigan United Auto Workers strikes at General Motors narrowly averted or postponed a labor-management confrontation fully capable of precipitating an economic meltdown with far reaching consequences for our increasingly global economy. This paper uses...

  7. European community light water reactor safety research projects. Experimental issue

    International Nuclear Information System (INIS)

    1975-01-01

    Research programs on light water reactor safety currently carried out in the European Community are presented. They cover: accident conditions (LOCA, ECCS, core meltdown, external influences, etc...), fault and accident prevention and means of mitigation, normal operation conditions, on and off site implications and equipment under severe accident conditions, and miscellaneous subjects

  8. The Disintegration of Teacher Preparation

    Science.gov (United States)

    Baines, Lawrence A.

    2010-01-01

    The disintegration of teacher certification programs in the united States holds an eerie similarity to the recent meltdown of American financial institutions. Similarly, the No Child Left Behind Act of 2001, whose purported purpose was to ensure that all students get highly qualified teachers (HQT), has had an unintentionally devastating effect on…

  9. "Jääaeg 2" : tiiger Diego kurvastas Marko Matveret / Jaanus Kulli

    Index Scriptorium Estoniae

    Kulli, Jaanus, 1955-

    2006-01-01

    Täispikk animafilm "Jääaeg 2 : Suur sula" ("Ice Age 2 : The Meltdown") : režissöör Carlos Sandanha : eestikeelse dublaazhi režissöör Peeter Simm : Ameerika Ühendriigid 2006. Filmi dubleerimisest dubleerijate kommentaaridega

  10. Royal Ahold : A Failure of Corporate Governance and an Accounting Scandal

    NARCIS (Netherlands)

    de Jong, A.; DeJong, D.V.; Mertens, G.M.H.; Roosenboom, P.G.J.

    2005-01-01

    Royal Ahold (Koninklijke Ahold NV) was one of the major success stories in the 1990s and is one of the major failures, suffering a complete meltdown, in 2003.We investigate the strategy, accounting transparency and corporate governance of Ahold; elements which jointly drive the firm s performance

  11. Leading the Way to the Third Industrial Revolution. Addressing the Triple Threat of the Global Financial Crisis, Energy Crisis, and Climate Change

    International Nuclear Information System (INIS)

    Rifkin, J.; Da Graca Carvalho, M.; Consoli, A.; Bonifacio, M.

    2008-01-01

    We are at a precarious point in history. We are facing the real prospect of an economic meltdown on the scale of the Great Depression. The credit crisis is compounded by the global energy crisis and the climate change crisis, creating a potential cataclysm for civilization. There is a way out: we need to radically overhaul the way we use energy in our society

  12. Corporate Governance: Insider Information, the Bane of Financial ...

    African Journals Online (AJOL)

    The finding is that the insider information possessed by the manager informed the manipulation of firms, securities, risky business, terms, prices, etc, for their benefit to the detriment of investors and therefore caused the financial melt-down. Finally, the major recommendation is that corporate governance needs reforms for ...

  13. Royal Ahold: A Failure Of Corporate Governance

    NARCIS (Netherlands)

    A. de Jong (Abe); D.V. DeJong; G.M.H. Mertens (Gerard); P.G.J. Roosenboom (Peter)

    2005-01-01

    textabstractRoyal Ahold (Koninklijke Ahold NV) was one of the major success stories in the 1990s and is one of the major failures in corporate governance, suffering a complete meltdown in 2003. This clinical study analyzes Ahold’s growth strategy through acquisitions and isolates the cause of the

  14. Guest Editorial

    African Journals Online (AJOL)

    denise

    these life-worlds. In our first manuscript, Meltdown in the Midst of. Beauty, we find an existential crisis of sorts between the blurry lines of partaking as a participant but also being a researcher in an early childhood artist's studio. Learning to listen to the children's ideas and go with them on a learning journey is paramount to.

  15. Safety oriented LWR research. Annual report 1990

    International Nuclear Information System (INIS)

    1991-07-01

    The contributions describe phenomenons of severe fuel damage and aspects of core meltdown accidents. These accidents deal with aerosol behaviour and ventilation systems and the methods for assessing and reducing the radiological concequences of nuclear accidents. Other contributions describe selected questions of safety of HCLWR type reactors. (DG)

  16. Multilingualism as Utopia: Fashioning Non-Racial Selves

    Science.gov (United States)

    Stroud, Christopher; Williams, Quentin

    2017-01-01

    The challenge of contemporary South Africa is that of building a (post)nation of postracial equity in a fragmented world of a globalized ethical, economic and ecological meltdown. In this paper, we seek to explore the idea of multilingualism as a technology in the conceptualization of alternative, competing futures. We suggest that multilingualism…

  17. Staying Up in a Down Economy

    Science.gov (United States)

    Pulley, John

    2009-01-01

    The fundraising landscape has been blistered by stock-market meltdowns and a financial sector that has repeatedly erupted in flames. In turn, the environment for development has turned icy, cooled by frozen credit markets and chilly consumer confidence. It is ragged, unstable terrain. Fundraisers, the ground moving beneath them, are unsure of…

  18. The Chornobyl accident and cognitive functioning: a follow-up study of infant evacuees at age 19 years

    NARCIS (Netherlands)

    Taormina, D.P.; Rozenblatt, S.; Guey, L.T.; Gluzman, S.F.; Carlson, G.A.; Havenaar, J.M.; Zakhozha, V.; Kotov, R.; Bromet, E.J.

    2008-01-01

    Background. The cognitive and academic outcomes of infants exposed to radiation after the meltdown at Chornobyl have been intensely debated. Western-based investigations indicate that no adverse effects occurred, but local studies reported increased cognitive impairments in exposed compared with

  19. Exploring Fiscal Policy at Zero Interest Rates in Intermediate Macroeconomics

    Science.gov (United States)

    Ramamurthy, Srikanth; Sedgley, Norman

    2013-01-01

    Since the financial meltdown of 2007, advanced macroeconomic theory has delved more deeply into the question of the appropriate fiscal policy when the nominal interest rate is close to or at zero percent. Such analysis is typically conducted with the aid of New Keynesian Dynamic Stochastic General Equilibrium models. The policy implications are,…

  20. POTENTIALS OF THE TELEVISION IN REINVENTING THE ...

    African Journals Online (AJOL)

    imitch

    In the wake of the recent global economic meltdown which started in the United States of America and has spread across the ... the rallying inspiration the lethargic tourism business is waiting for in Nigeria. ... Today with the rise of countries ...

  1. Applicability of Phebus FP results to severe accident safety evaluations and management measures

    International Nuclear Information System (INIS)

    Schwarz, M.; Clement, B.; Jones, A.V.

    2001-01-01

    The international Phebus FP (Fission Product) programme is the largest research programme in the world investigating core degradation and radioactive product release should a core meltdown accident occur in a light water reactor plant. Three integral experiments have already been performed. The experimental database obtained so far contains a wealth of information to validate the computer codes used for safety and accident management assessment

  2. Rethinking Vulnerability in the Age of Anthropocene: Toward Ecologizing Education

    Science.gov (United States)

    Li, Huey-li

    2017-01-01

    In this essay, Huey-li Li argues that, although precariousness has always been embedded in human existence, our human vulnerability has been heightened by seemingly omnipresent and omnipotent risks in the modern era, ranging from the 9/11 terroristic attacks and nuclear meltdowns to infectious disease outbreaks and climate change. Li unravels some…

  3. Does Europe Need a Comprehensive Energy Policy?

    NARCIS (Netherlands)

    Tol, R.S.J.

    2011-01-01

    The nuclear meltdown in Fukushima has given renewed momentum to the anti-nuclear power movement across Europe. However, the degree of momentum varies greatly from country to country, and considering the geographically widespread consequences of a nuclear accident, it hardly appears optimal for one

  4. Looking Back, Moving On: 2008 Best Notable Government Documents

    Science.gov (United States)

    Church, Jim

    2009-01-01

    If nothing else, 2008 was an eventful year for government information. People witnessed one of the most dramatic Presidential elections in U.S. history, the largest global economic meltdown since the Great Depression, and fundamental changes in the role of the federal government. As always, government information reflects the times people live in.…

  5. Slam Dunk

    Science.gov (United States)

    Herek, Matthew

    2011-01-01

    There's nothing like a worldwide financial meltdown to kick-start an alumni association's career networking offerings. In 2009, the Northwestern University alumni board provided clear direction to its regional affiliates and to the full-time staff working at the Evanston, Illinois, campus: Develop ways to purposefully connect alumni with each…

  6. Brookhaven lecture series No. 227: The Chernobyl accident

    International Nuclear Information System (INIS)

    Kouts, H.

    1986-01-01

    This lecture discusses the events leading to, during, and following the Chernobyl Reactor number 4 accident. A description of the light water cooled, graphite moderated reactor, the reactor site conditions leading to meltdown is presented. The emission of radioactive effluents and the biological radiation effects is also discussed. (FI)

  7. Working Group 7.0 Environmental Transport and Health Effects, Chernobyl Studies Project. Progress report, October 1994 -- March 1995

    International Nuclear Information System (INIS)

    Anspaugh, L.R.; Hendrickson, S.M.

    1995-01-01

    This document presents the details from the working group 7.0 Chernobyl Studies Project. This working group looked at the environmental transport and health effects from the fallout due to the meltdown of Chernobylsk-4 reactor. Topics include: hydrological transport; chromosome painting dosimetry; EPR, TL and OSL dosimetry; stochastic effects; thyroid studies; and leukemia studies

  8. 40 CFR 60.271 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... EAF begins to pour molten steel and ending either three minutes after steel ceases to flow from an EAF, or six minutes after steel begins to flow, whichever is longer. (i) Meltdown and refining means that... intermediate charging periods and times when power to the EAF is off. (k) Shop opacity means the arithmetic...

  9. Hydrogen transport in the containment

    International Nuclear Information System (INIS)

    Royl, P.; Mueller, C.; Travis, J.R.; Wilson, T.

    1995-01-01

    For the description of transport phenomena in water vapor/hydrogen mixtures released in nuclear meltdown accidents, an integrated analytical model is being developed for LWR containments. Thermal and mechanical loads due to recombination and combustion are to be calculable. The 3-dimensional GASFLOW code was taken over from LANL in exchange for HDR experimental results and Battelle BMC program results. (orig.)

  10. The 2013 Long-Term Budget Outlook

    Science.gov (United States)

    2013-09-01

    number of years, leading to substantial additional federal spending. For example, the nation could experience a massive earthquake, a nuclear meltdown...budget surpluses remaining after paying down publicly held debt available for redemption . a. For comparison with the current long-term projections, CBO

  11. Assessment of accident energetics in LMFBR core-disruptive accidents

    International Nuclear Information System (INIS)

    Fauske, H.K.

    1977-01-01

    An assessment of accident energetics in LMFBR core-disruptive accidents is given with emphasis on the generic issues of energetic recriticality and energetic fuel-coolant interaction events. Application of a few general behavior principles to the oxide-fueled system suggests that such events are highly unlikely following a postulated core meltdown event

  12. A consensus view on liquidity risk

    NARCIS (Netherlands)

    Acharya, V.; Krishnamurthy, A.; Perotti, E.

    2011-01-01

    Liquidity risk - which was at the heart of the September 2008 financial meltdown and explains regulatory concerns about a Greek default today - remains an open issue in financial regulatory reform. This column presents a consensus view of several leading academics on what more needs to be done to

  13. From strategy to e-strategy: lessons from two success stories

    NARCIS (Netherlands)

    Constantinides, Efthymios

    2006-01-01

    The article presents the results of research on the strategy of two internet corporations who survived the high-tech meltdown and became major online players and trendsetters in their industries. These two cases highlight the idiosyncracies of the virtual environment as a commercial platform and

  14. Teaching "Business" Ethics: Affecting Change through Self-Regulation and Reflection

    Science.gov (United States)

    Taylor-Bianco, Amy; Tucker, Mary; Rosado Feger, Ana; Barnett, Tanya

    2017-01-01

    Most young college graduates have witnessed a cascade of unethical and, indeed, unlawful business behavior from insider trading to credit card meltdown and governance misbehavior, to give a few examples. Yet, while college students indicate that ethical training is essential and should be expected as part of one's college education, there is much…

  15. Leading the Way to the Third Industrial Revolution. Addressing the Triple Threat of the Global Financial Crisis, Energy Crisis, and Climate Change

    Energy Technology Data Exchange (ETDEWEB)

    Rifkin, J.; Da Graca Carvalho, M.; Consoli, A.; Bonifacio, M.

    2008-12-15

    We are at a precarious point in history. We are facing the real prospect of an economic meltdown on the scale of the Great Depression. The credit crisis is compounded by the global energy crisis and the climate change crisis, creating a potential cataclysm for civilization. There is a way out: we need to radically overhaul the way we use energy in our society.

  16. An indirect effect of biological invasions: the effect of zebra mussel fouling on parasitisation of unionid mussels by bitterling fish

    Czech Academy of Sciences Publication Activity Database

    Vrtílek, Milan; Reichard, Martin

    2012-01-01

    Roč. 696, č. 1 (2012), s. 205-214 ISSN 0018-8158 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:68081766 Keywords : Non-native species * Coevolution * Invasional meltdown * Host-parasite relationship * Aquatic ecosystems Subject RIV: EG - Zoology Impact factor: 1.985, year: 2012

  17. Fukushima : The Geo-Trauma of a Futural Wave

    NARCIS (Netherlands)

    Dolphijn, R.; Cole, David; Bradley, Joff

    2016-01-01

    The enduring effects of the March 2011 tsunami and nuclear meltdown at the Fukushima Dai-ichi Nuclear Power Station in Japan are explored in this paper through the notions of “geo-trauma” in the authors’ work and geophilosophy in Deleuze and Guattari’s philosophy. At the fulcrum of the 2011 global

  18. Africa's 'Recovery': Economic Growth, Governance and Social Protest

    African Journals Online (AJOL)

    The reality behind the alleged recovery of Africa from the 2008/09 global financial meltdown, which has been well advertised by multilateral financial agencies, needs investigation, partly because the institutions' political agenda appears to be to further integrate the continent into a highly volatile world economy, as well as ...

  19. Annals of Modern Education - Vol 4, No 1 (2012)

    African Journals Online (AJOL)

    Home Background Variables and Technical Vocational Training of Secondary School Students in Akwa Ibom State During Global Economic Meltdown · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. EO Nsa, EO Akpan, AA Offiong, PS Williams, 1-10 ...

  20. LSA Large Area Silicon Sheet Task. Continuous Liquid Feed Czochralski Growth. [for solar cell fabrication

    Science.gov (United States)

    Fiegl, G.

    1979-01-01

    The design and development of equipment and processes to demonstrate continuous growth of crystals by the Czochralski method suitable for producing single silicon crystals for use in solar cells is presented. The growth of at least 150 kg of mono silicon crystal, 150 mm in diameter is continuous from one growth container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a meltdown system with a continuous solid silicon feed mechanism and a liquid transfer system, with associated automatic feedback controls is discussed. Due to the silicon monoxide build up in the furnace and its retarding effect on crystal growth the furnace conversion for operation in the low pressure range is described. Development of systems for continuous solid recharging of the meltdown chamber for various forms of poly silicon is described.

  1. Transuranium contamination in BWRs after fuel accidents and its impact on decommissioning exposures and costs

    Energy Technology Data Exchange (ETDEWEB)

    Lundgren, K.

    1996-12-01

    The theme of the present study is to quantify the amount of transuranium activity in different parts of the plant after various fuel accidents, and which impact such contamination has on radiation exposure and costs for decommissioning the plant. The consequences of four different accident degrees have been treated: Common fuel failures, e.g. in line with recent experiences from Swedish BWRs; Fuel channel obstruction resulting in partial melting of one fuel assembly; Total loss of electric power resulting in partial meltdown of the core, but with primary circuit intact preventing a massive contamination of the containment; A LOCA followed by a core meltdown and melting and penetration of the reactor pressure vessel. The amount of transuranium activity distributed, the form of this activity and the plant contamination are evaluated for these accidents. The costs and exposures have been split up on cleanup activities after the accident and decommissioning. 75 refs.

  2. Laboratory studies of the meltfront propagation in a borax core-catcher

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Werle, H.

    1980-08-01

    A series of seven laboratory experiments concerning the meltdown of a borax core catcher have been performed. By the selection of the simulant materials the most important thermophysical properties of the core catcher materials were taken into account. Fission product heating of the molten core masses was simulated by electrolytically heating of the molten region. The experiments reveal interesting details of the phenomena to be expected during melt-down of a borax core catcher, especially on the flow pattern, the mixing processes of molten materials and the layer formation the melt. The most interesting result is that the ratio of downward to sideward melting rate is heavily reduced by high melting barriers and that a cubic structure of barriers will not equalize downward and sideward melting rates. A super 8 film is available as additional information. (orig.) [de

  3. Transuranium contamination in BWRs after fuel accidents and its impact on decommissioning exposures and costs

    International Nuclear Information System (INIS)

    Lundgren, K.

    1996-12-01

    The theme of the present study is to quantify the amount of transuranium activity in different parts of the plant after various fuel accidents, and which impact such contamination has on radiation exposure and costs for decommissioning the plant. The consequences of four different accident degrees have been treated: Common fuel failures, e.g. in line with recent experiences from Swedish BWRs; Fuel channel obstruction resulting in partial melting of one fuel assembly; Total loss of electric power resulting in partial meltdown of the core, but with primary circuit intact preventing a massive contamination of the containment; A LOCA followed by a core meltdown and melting and penetration of the reactor pressure vessel. The amount of transuranium activity distributed, the form of this activity and the plant contamination are evaluated for these accidents. The costs and exposures have been split up on cleanup activities after the accident and decommissioning. 75 refs

  4. A current perspective on the risk significance of steam explosions

    International Nuclear Information System (INIS)

    Snyder, A.W.

    1982-01-01

    The view currently held in the Sandia National Laboratory is that, in the case of a meltdown in the reactor core, the probability of a steam explosion is greater than was estimated in WASH-1400, but that the extent and effect of an explosion will be very much smaller than assumed in WASH-1400. This results in a far smaller total risk with regard to containment. In WASH-1400, a nominal conditional probability of 1% was assumed for a containment rupture in a PWR-type reactor, should a large part of the reactor fuel be subject to meltdown during the course of the accident. The German risk analysis study 'Deutsche Risikostudie Kernkraftwerke' dated 1979 considers an explosion of a size sufficient to represent a threat to containment to be considerably more improbable than was assumed in WASH-1400. (orig./DG) [de

  5. CNE (central nuclear en Embalse): probabilistic safety study. Loss-of-coolant accidents. Analysis through events sequence

    International Nuclear Information System (INIS)

    Layral, S.I.

    1987-01-01

    The aim of this study was to perform for the Embalse nuclear power plant, a probabilistic evaluation of loss-of-coolant accidents (LOCA) to identify the risks associated with them and to determine their acceptability in accordance with norms. This study includes all ruptures in the primary system that produce the automatic activation of 'emergency core cooling system'. Three starting events were selected for the probabilistic evaluation: 100% rupture of an input collector; 5% rupture of an input collector; 1.2% rupture of an input collector. At this stage the evaluation is focussed on the identification and quantization of the main failure sequences that follow a LOCA and lead to an uncontrolled reactor state or 'core meltdown'. The most important contribution to the core meltdown due to LOCA is the failure of supplies that are required for the emergency core cooling system. (Author)

  6. Micro-organisms and nuclear waste: a neglected problem

    International Nuclear Information System (INIS)

    Arnott, Don.

    1989-01-01

    The paper addresses the problem of bacteria in nuclear waste disposal. A description is given of how bacteria colonised the Three Mile Island Nuclear Reactor soon after meltdown, demonstrating the ability of some bacteria to operate under extreme conditions. Work is also described indicating that microbial corrosion of metal canisters can occur. Thus the author recommends that studies of nuclear waste disposal should take into account the interrelations between geology, geochemistry and microbiology. (U.K.)

  7. Adaptive Standard Operating Procedures for Complex Disasters

    Science.gov (United States)

    2017-03-01

    Firefighters stuck in Ga . awaiting orders,” Greg Bluestein, Associated Press, September 7, 2005. 77 Sobel and Leeson, “Government’s Response to Hurricane...partial meltdowns in Reactors 2 and 3 as well as gas explosions that devastated several of the containment buildings, leaking radioactive material into... Behaviour in Built Environments,” Proceedings of the 30th eCAADe Conference 1, (2012): 532. 60 autonomous agents, which are capable of interacting with

  8. Third generation nuclear plants

    Science.gov (United States)

    Barré, Bertrand

    2012-05-01

    After the Chernobyl accident, a new generation of Light Water Reactors has been designed and is being built. Third generation nuclear plants are equipped with dedicated systems to insure that if the worst accident were to occur, i.e. total core meltdown, no matter how low the probability of such occurrence, radioactive releases in the environment would be minimal. This article describes the EPR, representative of this "Generation III" and a few of its competitors on the world market.

  9. Three Mile Island - The hour-by-hour account of what really happened

    International Nuclear Information System (INIS)

    Stephens, M.

    1980-01-01

    An hour-by-hour account is given of the progression of events leading up to and during the accident at the Three Mile Island Unit 2 reactor. The emergency procedures followed, the evacuation of local residents and the decisions taken as the possibility of a meltdown became apparent are recorded in detail together with aspects of the media coverage and the problems of communication. (U.K.)

  10. Comparison of computer codes relative to the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Bunz, H.; Dunbar, I.; Gauvain, J.; Ricchena, R.

    1986-01-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes (AEROSIM-M, UK; AEROSOLS/B1, France; CORRAL-2, CEC and NAUA Mod5, Germany) used in order to assess the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR. Topics considered in this paper include aerosols, containment buildings, reactor safety, fission product release, reactor cores, meltdown, and monitoring

  11. Radiological consequence analysis for upgradation of Pakistan Research Reactor-1 from 9 to 10 MW

    International Nuclear Information System (INIS)

    Khan, L.A.; Raza, S.S.

    1993-12-01

    Radiological consequence analysis has been carried out for upgradation of PARR-I from 9 to 10 MW. A hypothetical loss of coolant accident resulting in core meltdown and release of fission products to the atmosphere has been analyzed. Whole body and thyroid doses have been calculated as a function of time and distance from the containment building. Based on these dose estimates, boundaries of exclusion and low population zones are assessed. (author)

  12. Environmental impacts of an accident with a nuclear power plant

    International Nuclear Information System (INIS)

    1985-10-01

    A maximum credible reactor accident is considered: all safety systems fail and the reactor core is not cooled anymore. This so-called meltdown accident is discussed for two different weather situations. For these cases, the effects on public health and environment is studied (radioactive clouds, inhalation and deposition of radioactive materials). The radiation doses calculated are compared with standard levels. In so doing, an estimation is made of the measures necessary to reduce unfavourable consequences. (G.J.P.)

  13. Evaluation of results of Phase B of the German Risk Study for Nuclear Power Plants

    International Nuclear Information System (INIS)

    Fischer, B.; Hahn, L.; Sailer, M.

    1989-01-01

    The expert opinion summarizes and discusses the intermediate and the final results of Phase B of the German Risk Study. Emphasis is placed on systems analyses and event scenarios, core melt-down scenarios and effects on the containment, failure of the containment and resulting source terms, radioactivity transport and consequences of accidents, multi-system emergencies and external disturbances, accident management and means of mitigation of damage. (DG) [de

  14. The global food crisis : supply and demand revisited

    OpenAIRE

    Sammut, Vince

    2015-01-01

    This study aims to show that the volatility in food prices between 2008 and 2011 cannot be explained merely by the market fundamentals of demand and supply. While global changes in demand and supply are bringing about radical changes to the food equation, evidence shows that market failure in the world grain market aggravated the problem. Excess liquidity, brought about by monetary growth policies after the subprime crises and financial meltdown in 2008, has stimulated speculation and hoar...

  15. RA reactor safety analysis I-III, Part III - Environmental effect of the maximum credible accident; Analiza sigurnosti rada Reaktora RA I-III, III deo - Posledica maksimalno moguceg akcidenta na okolinu reaktora

    Energy Technology Data Exchange (ETDEWEB)

    Raisic, N [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1963-02-15

    The objective of the maximum credible accident analysis was to determine the integral radiation doses in the vicinity of the reactor and in the environment. In case of RA reactor the maximum credible accident, meaning release of the fission products, would be caused by fuel elements meltdown. This analysis includes the following calculation results: activity of the fission products, volatility of the fission products, concentration of radioactive materials in the air, analysis of the accident environmental effects.

  16. Location sites for nuclear power plants and the public drinking water supplies

    International Nuclear Information System (INIS)

    1987-05-01

    This report presents the results of a study by the Dutch RIWA- Working Group Nuclear Power Plants, of the possible effects of a nuclear-reactor melt-down accident upon the drinking-water supply in the Netherlands which is dependent on surface waters. The aim of this report is to contribute to the 're-consideration with regard to siting of nuclear power plants' of the Dutch government. In the case of a nuclear-reactor melt-down accident in the Netherlands or directly adjacent countries, surface waters destined for drinking-water production may be contaminated severely. The amount of contamination depends, among other things, upon the distance, wind direction, dry as well as wet deposition and the features of the place yielding drinking water. From calculations of contamination of surface waters in the case of open- supply build up it appears that the derived norm of the radionuclide cocktail may be exceeded for a period of weeks up to several months or even years. There are reasons to draw the same conclusion for supply build up in the dunes by means of surface infiltration in the dunes. A melt-down accident can cause very severe contamination. Also here it can be stated that, in the case of a calamity in the Netherlands or directly adjacent countries, a norm transgression may occur for weeks up to years. In view of the risks which nuclear power plants can hold for the drinking-water supply which depends upon surface-waters as basis element. Severe objections should be made with respect to the siting of nuclear power plants in the Netherlands unless the occurrence of melt-down accidents could be excluded. 11 refs.; 4 figs.; 7 tabs

  17. Analysis of natural convection in volumetrically-heated melt pools

    International Nuclear Information System (INIS)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R.

    1996-12-01

    Results of series of studies on natural convection heat transfer in decay-heated core melt pools which form in a reactor lower plenum during the progression of a core meltdown accident are described. The emphasis is on modelling and prediction of turbulent heat transfer characteristics of natural convection in a liquid pool with an internal energy source. Methods of computational fluid dynamics, including direct numerical simulation, were applied for investigation

  18. Properties of frozen dairy desserts processed by microfluidization of their mixes.

    Science.gov (United States)

    Olson, D W; White, C H; Watson, C E

    2003-04-01

    Sensory properties and rate of meltdown of nonfat (0% fat) and low-fat (2% fat) vanilla ice creams processed either by conventional valve homogenization or microfluidization of their mixes were compared with each other and to ice cream (10% fat) processed by conventional valve homogenization. Mixes for frozen dairy desserts containing 0, 2, and 10% fat were manufactured. Some of the nonfat and low-fat ice cream mixes were processed by microfluidization at 50, 100, 150, and 200 MPa, and the remaining nonfat and low-fat ice cream mixes and all of the ice cream mix were processed by conventional valve homogenization at 13.8 MPa, first stage, and 3.4 MPa, second stage. The finished frozen and hardened products were evaluated at d 1 and 45 for meltdown rate and for flavor and body and texture by preference testing. Nonfat and low-fat ice creams that usually had a slower meltdown were produced when processing their mixes by microfluidization instead of by conventional valve homogenization. Sensory scores for the ice cream were significantly higher than sensory scores for the nonfat and low-fat ice creams, but the sensory scores for the conventional valve homogenized controls for the nonfat ice cream and low-fat ice cream were not significantly different from the sensory scores for the nonfat ice cream and low-fat ice cream processed by microfluidization of the mixes, respectively. Microfluidization produced nonfat and low-fat ice creams that usually had a slower meltdown without affecting sensory properties.

  19. The Financial Crisis and White Collar Crime - Legislative and Policy Responses

    OpenAIRE

    Ryder, N.; Turksen, U.; Tucker, J.

    2017-01-01

    In September 2007, the collapse of the United States (US) sub-prime mortgage market resulted in the global meltdown of the financial markets. This in turn led to the collapse of many international financial institutions including Northern Rock, Bradford and Bingley, American Insurance Group, Freddy Mac, Fannie Mae and Lehman Brothers. The G20 countries responded with a plethora of financial stimulus packages aimed at combating the largest global financial problem since the Wall Street Crash i...

  20. CBO’s 2011 Long-Term Budget Outlook

    Science.gov (United States)

    2011-06-01

    larger catas- trophe could affect budgetary outcomes by reducing economic growth over a number of years, by requiring massive additional federal...change predict—or could experience a single massive earthquake, a nuclear meltdown that rendered a large area of the country uninhabitable, or an...the purchase price and the value paid at redemption . Treasury bond: A fixed-rate, interest-bearing security issued by the Treasury with an original

  1. The 2012 Long-Term Budget Outlook

    Science.gov (United States)

    2012-06-01

    growth over a number of years or requiring massive additional federal spending, or both. For exam- ple, the country could experience more-frequent severe...floods, hurricanes, tornadoes, and fires—as some models of climate change predict—or a single massive earth- quake, a nuclear meltdown that rendered...cumulative amount of surpluses remaining after paying down publicly held debt available for redemption . Debt does not reflect economic effects of the

  2. THE ROLE OF DERIVATIVES IN THE FINANCIAL CRISIS AND THEIR IMPACT ON SECURITY PRICES

    OpenAIRE

    Ronald A. Stunda

    2014-01-01

    This study takes on two divergent notions concerning derivatives; that they are dangerous instruments (Warren Buffet) versus the concept that they help to reduce risk (Allen Greenspan). These notions are assessed from the perspective of the recent Financial Crisis in which derivatives were assigned a good deal of the blame for the meltdown. This study analyzes three different study periods; Pre-Crisis (2003, 2004, 2005), Crisis (2008, 2009, 2010), and Post-Crisis (2011, 2012, 2013-1st quarter...

  3. Exchange traded funds (etf): evaluation and portfolio building from etf’s

    OpenAIRE

    Valukonis, Mantas

    2010-01-01

    As the global financial crisis is started, investors are trying to look for new investment methods. During the meltdown of most shares, share investments are becoming unattractive, it decreases the liquidity of the exchange itself. As bears are dominating in share markets, more and more investors choose various alternatives of investments. One of them is Exchange Traded Funds, therefore a closer acquaintance with the management, features and advantages of these funds is needed. In order to ch...

  4. Inflation Dynamics in India: An Analysis

    OpenAIRE

    Nair, Manju S

    2014-01-01

    India has exhibited high variability in inflation during the last eight years owing to both internal and external factors. The Global Financial Meltdown, recurrent increase in global oil prices, wage employment programmes, widening current account deficits etc resulted in fluctuations in inflation. These factors have a direct influence on variables like output, money supply, exchange rate which in turn affect inflation. In this context, the study employs a Cointegrated Vector Auto Regressi...

  5. Acoustic Waves: A Route to Enhance Sodium Fast Reactor Safety

    International Nuclear Information System (INIS)

    Jeannot, Jean-Philippe; Baque, François; Cavaro, Matthieu; Gastaldi, Olivier; Lhuilier, Christian; Massacret, Nicolas; Moriot, Jérémy; Paumel, Kévin; Vandergaegen, Matthias; Rodriguez, Gilles

    2013-01-01

    Improvement to prevent core meltdown and to provide a more robust safety demonstration → Safety objectives: - A level of safety at least equivalent to EPR’s level, - Consolidation of the defence-in-depth principle, - A more robust safety demonstration than those of the Phenix and Superphenix reactor. Acoustic techniques: - Low attenuation by the sodium medium - High velocity of US wave (2289 m.s-1 at 550°C) →

  6. List of the reports from reactor safety research of the BMFT and USNRC

    International Nuclear Information System (INIS)

    1977-02-01

    This list presents a survey of reports from the FRG and USA issued on special problems of reactor safety research. The problems include emergency core cooling, the containment during loss of coolant, core meltdown, component safety, external impacts, risk and reliability, quality assurance, fission product transport, radiation exposure, as well as the LWR, HTR and the fast sodium-cooled reactor in general. (orig./HK) [de

  7. Does Europe need a comprehensive energy policy?

    OpenAIRE

    Egenhofer, Christian; Behrens, Arno; Tol, Richard S. J.; Berthélemy, Michel; Lévêque, François; Jansen, Jaap C.

    2011-01-01

    The nuclear meltdown in Fukushima has given renewed momentum to the anti-nuclear power movement across Europe. However, the degree of momentum varies greatly from country to country, and considering the geographically widespread consequences of a nuclear accident, it hardly appears optimal for one country to ban nuclear power while multiple nuclear power plants are still active in neighbouring countries. Even beyond the nuclear power dilemma, the economic and political externalities associate...

  8. 日本の地域社会と原子力発電所 -福井県大飯町を事例にして-

    OpenAIRE

    小松, 秀雄; Hideo, KOMATSU

    2012-01-01

    The Tokyo Electric Power Fukushima Daiichi Nuclear was caused by the huge tsunami of the Great East Japan Earthquake that hit on March 11, 2011.The nuclear reactors were led to meltdown and hydrogen explosion, resulting in the release of large amounts of radioactive materials into the air. Many of the residents in nearby areas were forced to evacuate and are unable to return to their hometowns even today. After careful consideration of these results of the Fukushima Daiichi Nuclear accident, ...

  9. The Changing Landscape Of The Indian Banking Industry: An Empirical Study

    OpenAIRE

    Sivakumar Venkataramany; Balbir B. Bhasin

    2012-01-01

    While global financial deregulation has led to liberalization of financial services and thus to modernization of commercial banking, industrialized economies are facing a financial meltdown. The health of the major global banking industry is under severe stress, but India continues to be strong. Despite cost prohibitive efforts in the introduction of a range of new products and services, banks in India are striving to emerge from an era of development banking into consumer-oriented supermarke...

  10. Nuclear reactor core safety device

    International Nuclear Information System (INIS)

    Colgate, S.A.

    1977-01-01

    The danger of a steam explosion from a nuclear reactor core melt-down can be greatly reduced by adding a gasifying agent to the fuel that releases a large amount of gas at a predetermined pre-melt-down temperature that ruptures the bottom end of the fuel rod and blows the finely divided fuel into a residual coolant bath at the bottom of the reactor. This residual bath should be equipped with a secondary cooling loop

  11. Analysis of natural convection in volumetrically-heated melt pools

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Dinh, T.N.; Nourgaliev, R.R. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Nuclear Power Safety

    1996-12-01

    Results of series of studies on natural convection heat transfer in decay-heated core melt pools which form in a reactor lower plenum during the progression of a core meltdown accident are described. The emphasis is on modelling and prediction of turbulent heat transfer characteristics of natural convection in a liquid pool with an internal energy source. Methods of computational fluid dynamics, including direct numerical simulation, were applied for investigation. Refs, figs, tabs.

  12. Severe fuel damage in steam and helium environments observed in in-reactor experiments

    International Nuclear Information System (INIS)

    Saito, S.; Shiozawa, S.

    1984-01-01

    The bahavior of severe fuel damages has been studied in gaseous environments simulating core uncovery accidents in the in-reactor experiments utilizing the NSRR. Two types of cladding relocation modes, azimuthal flow and melt-down, were revealed through the parametric experiments. The azimuthal flow was evident in an oxidizing environment in case of no oxide film break. The melt-down can be categorized into flow-down and move-down, according to the velocity of the melt-down. Cinematographies showed that the flow-down was very fast as water flows down while the move-down appeared to be much slower. The flow-down was possible in an unoxidizing environment, whereas the move-down of molten cladding occured through a crack induced in an oxide film in an oxidizing environment. The criterion of the relocation modes was developed as a function of peak cladding temperature and oxidation condition. It was also found that neither immediate quench nor fuel fracture occurred upon flooding when cladding temperature was about 1800 0 C at water injection. The external mechanical force is needed for fuel fracture. (orig.)

  13. Neutronics simulations on hypothetical power excursion and possible core melt scenarios in CANDU6

    International Nuclear Information System (INIS)

    Kim, Yonghee

    2015-01-01

    LOCA (Loss of coolant accident) is an outstanding safety issue in the CANDU reactor system since the coolant void reactivity is strongly positive. To deal with the LOCA, the CANDU systems are equipped with specially designed quickly-acting secondary shutdown system. Nevertheless, the so-called design-extended conditions are requested to be taken into account in the safety analysis for nuclear reactor systems after the Fukushima accident. As a DEC scenario, the worst accident situation in a CANDU reactor system is a unprotected LOCA, which is supposed to lead to a power excursion and possibly a core melt-down. In this work, the hypothetical unprotected LOCA scenario is simulated in view of the power excursion and fuel temperature changes by using a simplified point-kinetics (PK) model accounting for the fuel temperature change. In the PK model, the core reactivity is assumed to be affected by a large break LOCA and the fuel temperature is simulated to account for the Doppler effect. In addition, unlike the conventional PK simulation, we have also considered the Xe-I model to evaluate the impact of Xe during the LOCA. Also, we tried to simulate the fuel and core melt-down scenario in terms of the reactivity through a series of neutronics calculations for hypothetical core conditions. In case of a power excursion and possible fuel melt-down situation, the reactor system behavior is very uncertain. In this work, we tried to understand the impacts of fuel melt and relocation within the pressure vessel on the core reactivity and failure of pressure and calandria tubes. (author)

  14. Main results of German risk study, Phase B, in the light of methodological problems

    International Nuclear Information System (INIS)

    Koeberlein, K.

    1991-01-01

    The German Risk Study, Phase B, which has been performed for a 1,300 MWe KWU-type pressurized water reactor, is a level 2 probabilistic safety assessment (PSA). In the study, 32 initiating events have been considered. An expected plant damage state frequency of about 3x10 -5 per year has been calculated. In a plant damage state core meltdown can only be prevented by means of accident management procedures. The probability is high (about 98%) that in a plant damage state the primary system will not be depressurized. Core meltdown under high system pressure would endanger the containment integrity immediately. In most plant damage states accident management procedures are possible which bring the plant in a safe state or, at least, reduce the pressure in the primary system before the pressure vessel fails. On a preliminary basis, a success probability of 99% for accident management procedures (secondary or primary side bleed and feed) has been estimated. This results in an expected core melt frequency of about 4x10 -6 per year. The expected frequency of high pressure core meltdown is about 6x10 -7 per year. Loads on, and failure modes of, the containment during a core melt accident as well as release fractions after containment failure have been analyzed. The study did, however, refrain from quantifying the probability of containment failure modes. A main uncertainty in this area is the probability of containment failure due to hydrogen burning. The results of the study point out, that the risk can be reduced significantly if containment failure due to hydrogen burning can be reliably prevented

  15. Event course analysis of core disruptive accidents

    International Nuclear Information System (INIS)

    Hering, W.; Homann, C.; Sengpiel, W.; Struwe, D.; Messainguiral, C.

    1995-01-01

    The theortical studies of the behavior of a PWR core in a meltdown accident are focused on hydrogen release, materials redistribution in the core area including forming of an oxide melt pool, quantity of melt and its composition, and temperatures attained by the RPV internals (esp. in the upper plenum) during the accident up to the time of melt relocation into the lower plenum. The calculations are done by the SCDAP/RELAP5 code. For its validation selected CORA results and Phebus FPTO results have been used. (orig.)

  16. Event course analysis of core disruptive accidents; Ereignisablaufanalyse kernzerstoerender Unfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Hering, W.; Homann, C.; Sengpiel, W.; Struwe, D.; Messainguiral, C.

    1995-08-01

    The theortical studies of the behavior of a PWR core in a meltdown accident are focused on hydrogen release, materials redistribution in the core area including forming of an oxide melt pool, quantity of melt and its composition, and temperatures attained by the RPV internals (esp. in the upper plenum) during the accident up to the time of melt relocation into the lower plenum. The calculations are done by the SCDAP/RELAP5 code. For its validation selected CORA results and Phebus FPTO results have been used. (orig.)

  17. Incident at university research facility - melt down of gas chromatograph evaporation block and failure of a passive safety barrier

    DEFF Research Database (Denmark)

    Jensen, Niels; Jørgensen, Sten Bay

    2014-01-01

    Two incidents are described highlighting the importance of process hazard analysis in university laboratories. In the first incident, an online gas chromatograph (GC) was being developed. A complete meltdown of the heating blog was experienced during testing because the PC had failed to turn off...... the heating of the evaporation circuit. There had been no design review of the GC, nor any code review of the software controlling the GC. Neither had there been any management of change review for the introduction of the GC in the pilot plant environment, and so the GC had been introduced without any...

  18. ATHENA-2D: A computer code for simulation of hypothetical recriticality accidents in a thermal neutron spectrum

    International Nuclear Information System (INIS)

    Schwinkendorf, K.N.

    1995-01-01

    In a damaged light water reactor core (as in the aftermath of a Three-Mile-Island-like core meltdown), water reflood is performed to carry off decay heat. The severely degraded geometry of the fuel debris bed may increase core reactivity with water reflood. Sufficient boron poisoning of the reflood water is therefore very important. One hypothetical accident is the reintroduction of cooling water that is insufficiently borated, resulting in the damaged reactor attaining criticality in this uncontrolled configuration. The goal in simulating this accident is the prediction of the energy release from the resulting transient

  19. Simulation of LOF accidents with directly electrical heated UO2 pins

    International Nuclear Information System (INIS)

    Alexas, A.

    1976-01-01

    The behavior of directly electrical heated UO 2 pins has been investigated under loss of coolant conditions. Two types of hypothetical accidents have been simulated, first, a LOF accident without power excursion (LOF accident) and second, a LOF accident with subsequent power excursion (LOF-TOP accident). A high-speed film shows the sequence of events for two characteristic experiments. In consequence of the high-speed film analysis as well as the metallographical evaluation statements are given in respect to the cladding meltdown process, the fuel melt fraction and the energy input from the beginning of a power transient to the beginning of the molten fuel ejections

  20. Apparatus for controlling nuclear core debris

    International Nuclear Information System (INIS)

    Jones, R.D.

    1978-01-01

    Disclosed is an apparatus for containing, cooling, and dispersing reactor debris assumed to flow from the core area in the unlikely event of an accident causing core meltdown. The apparatus includes a plurality of horizontally disposed vertically spaced plates, having depressions to contain debris in controlled amounts, and a plurality of holes therein which provide natural circulation cooling and a path for debris to continue flowing downward to the plate beneath. The uppermost plates may also include generally vertical sections which form annular-like flow areas which assist the natural circulation cooling

  1. Safety analysis of RA reactor operation, I-III, Part III - Environmental effect of the maximum credible accident; Analiza sigurnosti rada reaktora RA - I-III, III deo - Posledica maksimalno moguceg akcidenta na okolinu reaktora

    Energy Technology Data Exchange (ETDEWEB)

    Raisic, N [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1963-02-15

    Maximum credible accident at the RA reactor would consider release of fission products into the environment. This would result from fuel elements failure or meltdown due to loss of coolant. The analysis presented in this report assumes that the reactor was operating at nominal power at the moment of maximum possible accident. The report includes calculations of fission products activity at the moment of accident, total activity release during the accident, concentration of radioactive material in the air in the reactor neighbourhood, and the analysis of accident environmental effects.

  2. A three-dimensional radiation image display on a real space image created via photogrammetry

    Science.gov (United States)

    Sato, Y.; Ozawa, S.; Tanifuji, Y.; Torii, T.

    2018-03-01

    The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the occurrence of a large tsunami caused by the Great East Japan Earthquake of March 11, 2011. The radiation distribution measurements inside the FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a three-dimensional (3D) image reconstruction method for radioactive substances using a compact Compton camera. Moreover, we succeeded in visually recognizing the position of radioactive substances in real space by the integration of 3D radiation images and the 3D photo-model created using photogrammetry.

  3. Accident at Harrisburg

    International Nuclear Information System (INIS)

    1979-05-01

    The course of events during the accident on 28 March 1979 at Three Mile Island-2 Reactor at Harrisburg, Pennsylvania, is described in detail. The effects (in the environment and within the safety containment) are described. The following points are then discussed: the possibility of a comparable accident occurring in the nuclear power stations in the German Federal Republic; the possibility of any point having been overlooked in the design of nuclear power stations in the Federal Republic; whether previous risk analyses are still valid; and how near the Three Mile Island reactor was to a core meltdown. Some conclusions are drawn. (U.K.)

  4. Subprime Rescue Plans: Backdoor Bank Bailouts

    OpenAIRE

    Dean Baker

    2008-01-01

    This report analyzes recent proposals suggesting that the government buy up or guarantee bad mortgage debt in an attempt to slow the increasing number of foreclosures the nation has seen in the wake of the housing market's meltdown. The study, which focuses on the plan put forth by the Office of Thrift Supervision, shows that banks and mortgage holders end up being the true beneficiaries of such plans at the expense of taxpayers and with few gains for the majority of homeowners currently faci...

  5. Use of decision trees for evaluating severe accident management strategies in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Jae, Moosung [Hanyang Univ., Seoul (Korea, Republic of). Dept. of Nuclerar Engineering; Lee, Yongjin; Jerng, Dong Wook [Chung-Ang Univ., Seoul (Korea, Republic of). School of Energy Systems Engineering

    2016-07-15

    Accident management strategies are defined to innovative actions taken by plant operators to prevent core damage or to maintain the sound containment integrity. Such actions minimize the chance of offsite radioactive substance leaks that lead to and intensify core damage under power plant accident conditions. Accident management extends the concept of Defense in Depth against core meltdown accidents. In pressurized water reactors, emergency operating procedures are performed to extend the core cooling time. The effectiveness of Severe Accident Management Guidance (SAMG) became an important issue. Severe accident management strategies are evaluated with a methodology utilizing the decision tree technique.

  6. Apparatus for controlling nuclear core debris

    Science.gov (United States)

    Jones, Robert D.

    1978-01-01

    Nuclear reactor apparatus for containing, cooling, and dispersing reactor debris assumed to flow from the core area in the unlikely event of an accident causing core meltdown. The apparatus includes a plurality of horizontally disposed vertically spaced plates, having depressions to contain debris in controlled amounts, and a plurality of holes therein which provide natural circulation cooling and a path for debris to continue flowing downward to the plate beneath. The uppermost plates may also include generally vertical sections which form annular-like flow areas which assist the natural circulation cooling.

  7. A second chance for nuclear power

    International Nuclear Information System (INIS)

    Martin, Richard

    2017-01-01

    At the Shanghai Institute of Applied Physics, China, there are plans to build an experimental molten- salt reactor whose design makes meltdown far less likely. A 'virtual' reactor displays an intricate system of pipes carrying the cooling fluid that makes this system special, and then carries heat to drive the turbine and make electricity. Alvin Weinberg was the pioneering nuclear physicist at Oak Ridge National Laboratory, who developed a prototype molten-salt reactor from 1965-1969, before it fell out of favour.

  8. IRSN-ANCCLI partnership. Work session on Complementary safety assessments - November 2011

    International Nuclear Information System (INIS)

    Lachaume, Jean-Luc; Lheureux, Yves; Sene, Monique; Sene, Raymond; Jorel, Martial; Lavarenne, Caroline; Rousseau, Jean-Marie; Rebour, Vincent; Baumont, David; Dupuy, Patricia

    2011-11-01

    After an overview by the ASN of complementary safety assessments and an assessment of 'post-Fukushima' inspections of basic nuclear installations, the contributions (Power Point presentations) of this seminar proposed: the opinion of the Gravelines CLI (local information commission) on the Gravelines complementary safety assessment report, an analysis and discussion by the GSIEN on reports of complementary assessment of safety of nuclear installations with respect to the Fukushima accident, an analysis by the IRSN of complementary safety assessments performed by operators, the IRSN approach to analyze complementary safety assessments, reports on installation conditions, external flooding and seismic hazard, 'meltdown prevention' aspects in the management of accidental situations in EDF reactors

  9. Fabrication of uranium carbide/beryllium carbide/graphite experimental-fuel-element specimens

    International Nuclear Information System (INIS)

    Muenzer, W.A.

    1978-01-01

    A method has been developed for fabricating uranium carbide/beryllium carbide/graphite fuel-element specimens for reactor-core-meltdown studies. The method involves milling and blending the raw materials and densifying the resulting blend by conventional graphite-die hot-pressing techniques. It can be used to fabricate specimens with good physical integrity and material dispersion, with densities of greater than 90% of the theoretical density, and with a uranium carbide particle size of less than 10 μm

  10. Why the Federal Reserve Failed to See the Financial Crisis of 2008: The Role of “Macroeconomics” as a Sense making and Cultural Frame

    OpenAIRE

    Fligstein, Neil; Brundage, Jonah S; Schultz, Michael

    2014-01-01

    One of the puzzles about the financial crisis of 2008 is why the regulators were so slow to recognize the impending collapse of the financial system. In this paper, we propose a novel account of what happened. We analyze the meeting transcripts of the Federal Reserve’s main decision-making body, the Federal Open Market Committee (FOMC), to show that they had surprisingly little recognition that a serious economic meltdown was underway even after the collapse of Lehman Brothers on September 15...

  11. Why the Federal Reserve Failed to See the Financial Crisis of 2008: The Role of “Macroeconomics†as a Sense making and Cultural Frame

    OpenAIRE

    Fligstein, Neil; Brundage, Jonah S; Schultz, Michael

    2014-01-01

    One of the puzzles about the financial crisis of 2008 is why the regulators were so slow to recognize the impending collapse of the financial system. In this paper, we propose a novel account of what happened. We analyze the meeting transcripts of the Federal Reserve’s main decision-making body, the Federal Open Market Committee (FOMC), to show that they had surprisingly little recognition that a serious economic meltdown was underway even after the collapse of Lehman Brothers on September ...

  12. What is the purpose of risk studies

    International Nuclear Information System (INIS)

    Birkhofer, A.

    1986-01-01

    Over the past few years, more or less comprehensive risk analyses have been carried out for numerous nuclear power plants, especially in the USA. The first risk studies conducted, especially the Rasmussen Study and the 'German Risk Study,' investigated sequences of accidents up to their environmental impacts. Risk studies today are focused mostly on assessments of technical safety, which is why they are extended only as far as the determination of core meltdown frequencies or radionuclide releases. Studies of this type are also called probabilistic safety analyses. (orig.) [de

  13. Inherent safe fast breeder reactors and actinide burners, metallic fuel

    International Nuclear Information System (INIS)

    Dorner, S.; Schumacher, G.

    1991-04-01

    Nuclear power without breeder strategy uses the possibilities for the energy supply only to a small extend compared to the possibilities of fast breeder reactors, which offer an energy supply for thousands of years. Moreover, a fast neutron device offers the opportunity to run an actinide-burner that could improve the situation of waste management. Within this concept metallic fuel could play a key role. The present report shows some important aspects of the concept like the pyrometallic reprocessing, the behaviour of metallic fuel during a core meltdown accident and others. The report should contribute to the discussion of these problems and initialize further work

  14. Nuclear Safety Project. Annual report 1986

    International Nuclear Information System (INIS)

    1987-09-01

    The annual report 1986 is a detailed description of work within the Nuclear Safety Project performed in 1986 in the nuclear safety field by KfK institutes and departments and by external institutes on behalf of KfK. It includes individual research activities on dynamic loads and strains of reactor components under accident conditions, fuel behaviour under accident conditions, investigation and control of LWR core-meltdown accidents, improvement of fission product retention and reduction of radiation exposure, and on behaviour, impact and removal of released pollutants. (DG)

  15. Papers presented as part of the status report of the Nuclear Safety Research Project of the Karlsruhe Nuclear Center on 23 March 1994

    International Nuclear Information System (INIS)

    Hueper, R.

    1994-05-01

    The ten papers deal with the state of safety requirements on future LWR plants and with nuclear safety research with regard to fast reactors and future PWR plants. In particular, passive after-heat removal, core disruptive accidents, and actinide burning in fast reactors are analysed. For PWR type plants the fuel element behaviour in the event of accidents, hydrogen distribution and hydrogen fires, and the origin and effects of steam explosions on the reactor pressure vessel and the containment are examined. Core meltdown cooling systems are suggested. (DG) [de

  16. Results of research and development works 1982

    International Nuclear Information System (INIS)

    1983-02-01

    Arranged by main topics of research, the following contributions of the Institute are disposed as follows: 1. Fast Breeder Reactor Project (PSB) 1.1 Nuclear fuels and fuel elements 1.2 Cladding and core structure materials 1.3 Plant structure materials 1.4 Safety investigations 2. Nuclear Safety Project (PNS) 2.1 Fuel element behaviour during accidents 2.2 Core meltdown 3. Reprocessing and Waste Management Project (PWA) 4. Fusion technology (FT) 5. Innovations and new tasks (INNA). (orig./IHOe) [de

  17. Use of PSA for improving the safety of French PWRs

    International Nuclear Information System (INIS)

    Lanore, J.M.; Chambon, J.L.

    1994-06-01

    Two French PWR Probabilistic Safety Assessment (PSA) studies were conducted for the standardized PWR series of 900 and 1300 MWe. Both PSA 900 and PSA 1300 are level 1 PSAs, that means their objective is the evaluation of core meltdown frequency. These studies have some specific features, in particular the treatment of shutdown conditions, the treatment of long term post-accidental situations, and a wide use of French experience feedback. The PSAs are used for safety improvements of the French PWRs. Following the PSA results, several modifications to plants concerning the dominant sequences were decided. (R.P.). 2 refs., 4 figs

  18. Apparatus for controlling molten core debris

    International Nuclear Information System (INIS)

    Golden, M.P.; Tilbrook, R.W.; Heylmun, N.F.

    1972-01-01

    Disclosed is an apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed. 9 claims, 22 figures

  19. Modelling of QUENCH-03 and QUENCH-06 Experiments Using RELAP/SCDAPSIM and ASTEC Codes

    Directory of Open Access Journals (Sweden)

    Tadas Kaliatka

    2014-01-01

    Full Text Available To prevent total meltdown of the uncovered and overheated core, the reflooding with water is a necessary accident management measure. Because these actions lead to the generation of hydrogen, which can cause further problems, the related phenomena are investigated performing experiments and computer simulations. In this paper, for the experiments of loss of coolant accidents, performed in Forschungszentrum Karlsruhe, QUENCH-03 and QUENCH-06 are modelled using RELAP5/SCDAPSIM and ASTEC codes. The performed benchmark allowed analysing different modelling features. The recommendations for the model development are presented.

  20. Innovations in systems engineering and analysis for the simulation of beyond design-base accidents

    International Nuclear Information System (INIS)

    Frisch, W.; Beraha, D.

    1990-01-01

    An important target in improving reactor safety is to have the most realistic simulation possible of beyond design-base accidents in the computer. This paper presents new developments in ATHLET and further developments (description of the thermo-fluid-dynamic conditions in the core and cooling circuits during serious incidents in the computer programme ATHLET-SA) and extensions (link-up to RALOC). RALOC is a computer programme for describing thermodynamic conditions inside the containment during design-base accidents and accidents involving core meltdown. Further research is dedicated to code acceleration. (DG) [de

  1. Is nuclear power safe enough

    Energy Technology Data Exchange (ETDEWEB)

    Andresen, A F [Institutt for Atomenergi, Kjeller (Norway)

    1979-01-01

    The lecture formed a commentary on the report of the Norwegian Government's Commission on Nuclear power Safety which was published in October 1978. It was introductorily pointed out that 'safe' and 'safety' are not in themselves meaningful terms and that the probability of an occurrence is the real measure. The main items in the Commission's report have been core meltdown, releases during reprocessing, waste disposal, plutonium diversion and environmental impacts. The 21 members of the Commission were unanimous in 7 of the 8 chapters. In chapter 2, 'Summary and Conclusions', 3 members dissented from the majority opinion, that, subject to certain conditions, nuclear power was a safe and acceptable source of energy.

  2. Reports on BMBF-sponsored research projects in the field of reactor safety. Reporting period 1 July - 31 December 1995

    International Nuclear Information System (INIS)

    1996-01-01

    The Gesellschaft fuer Anlagen- und Reaktorsicherheit informs of the status of LWR tasks and projects on the safety of advanced reactors. Each progress report represents a compilation of individual reports about objectives, the work performed, the results, and the next steps of the works. The individual reports of quality assurance, safety of reactor component, emergency core cooling, lors of coolant, meltdown, fission product release, risk and reliability, are classified according to projects to the reactor safety research program. Another table uses the same classification system as applied in the nuclear safety index of the CEC. (DG)

  3. Nuclear power a reference handbook

    CERN Document Server

    Henderson, Harry R

    2014-01-01

    In the 21st century, nuclear power has been identified as a viable alternative to traditional energy sources to stem global climate change, and condemned as risky to human health and environmentally irresponsible. Do the advantages of nuclear energy outweigh the risks, especially in light of the meltdown at the Fukushima plant in 2011? This guide provides both a comprehensive overview of this critical and controversial technology, presenting reference tools that include important facts and statistics, biographical profiles, a chronology, and a glossary. It covers major controversies and proposed solutions in detail and contains contributions by experts and important stakeholders that provide invaluable perspective on the topic.

  4. Normal accidents living with high-risk technologies

    CERN Document Server

    Perrow, Charles

    1984-01-01

    Normal Accidents analyzes the social side of technological risk. Charles Perrow argues that the conventional engineering approach to ensuring safety--building in more warnings and safeguards--fails because systems complexity makes failures inevitable. He asserts that typical precautions, by adding to complexity, may help create new categories of accidents. (At Chernobyl, tests of a new safety system helped produce the meltdown and subsequent fire.) By recognizing two dimensions of risk--complex versus linear interactions, and tight versus loose coupling--this book provides a powerful framework for analyzing risks and the organizations that insist we run them.

  5. Chernobyl: recovery operations and the entombment of Reactor 4

    International Nuclear Information System (INIS)

    Dalziel, S.P.C.

    1988-01-01

    The immediate actions taken following the accident at the Chernobyl-number 4 reactor in April 1986 are described. These included actions to put out the fires, initial medical aid and the dropping of sand, lead, dolomite and boron onto the reactor from helicopters. Following this the chamber below the damaged reactor core was filled with concrete to prevent any further explosions or meltdown. The reactor was subsequently entombed in steel and concrete. The evacuation of the surrounding area is also mentioned. (U.K.)

  6. Arguments against nuclear engineering

    International Nuclear Information System (INIS)

    Hahn, L.

    1991-01-01

    The arguments put forward are: data from risk studies concerning the frequency of occurrence of core meltdown in LWR type reactors, the frequency of containment failures and resulting off-site emissions, in-plant accident management, and the hazard of hydrogen explosions. Yet unresolved problems are stated to be: the presentation of results of the German Risk Study (part DRS-B), the way accident management is dealt with, the evaluation standards applied to safety deficits, the hydrogen problem, the biological effects of low-dose radiation, the qualification of radwaste repositories, the information policy of public authorities, and the regime of governmental control and supervision. (HP) [de

  7. Current position on severe accident phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Robert E [Fauske and Associates, Inc., Burr Ridge, IL (United States)

    2004-07-01

    The phenomena addressed in this lecture are: in-vessel and ex-vessel hydrogen generation; in-vessel and in-containment natural circulation, steam explosions, direct containment heating, core-concrete interaction; debris coolability, containment strength/failure. The following events were modeled: axial and radial power distribution, two-phase level in the core, steam generation in covered section, decay heat generation, convection to gas, cladding oxidation, cold ballooning and rupture, natural circulation between the core and upper plenum, hydrogen generation, core meltdown, reflooding. Differences between PWR and BWR type reactors.

  8. Current position on severe accident phenomena

    International Nuclear Information System (INIS)

    Henry, Robert E.

    2004-01-01

    The phenomena addressed in this lecture are: in-vessel and ex-vessel hydrogen generation; in-vessel and in-containment natural circulation, steam explosions, direct containment heating, core-concrete interaction; debris coolability, containment strength/failure. The following events were modeled: axial and radial power distribution, two-phase level in the core, steam generation in covered section, decay heat generation, convection to gas, cladding oxidation, cold ballooning and rupture, natural circulation between the core and upper plenum, hydrogen generation, core meltdown, reflooding. Differences between PWR and BWR type reactors

  9. Passive decay heat removal by natural air convection after severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Erbacher, F.J.; Neitzel, H.J. [Forschungszentrum Karlsruhe Institut fur Angewandte Thermo- und Fluiddynamik, Karlsruhe (Germany); Cheng, X. [Technische Universitaet Karlsruhe Institut fur Stroemungslehre und Stroemungsmaschinen, Karlsruhe (Germany)

    1995-09-01

    The composite containment proposed by the Research Center Karlsruhe and the Technical University Karlsruhe is to cope with severe accidents. It pursues the goal to restrict the consequences of core meltdown accidents to the reactor plant. One essential of this new containment concept is its potential to remove the decay heat by natural air convection and thermal radiation in a passive way. To investigate the coolability of such a passive cooling system and the physical phenomena involved, experimental investigations are carried out at the PASCO test facility. Additionally, numerical calculations are performed by using different codes. A satisfying agreement between experimental data and numerical results is obtained.

  10. Europe after Fukushima. German perspectives on the future of nuclear power

    International Nuclear Information System (INIS)

    Temple, Samuel; Uekoetter, Frank; Kersten, Jens; Vogt, Markus

    2012-01-01

    One year after the reactor meltdown at the Fukushima Daiichi Nuclear Power Station, this volume of RCC Perspectives takes stock of its impact and possible legacy in Europe as part of the Rachel Carson Center's research focus on natural disasters and cultures of risk. While Europe may have been spared radioactive fallout, political and cultural fallout has been significant. Are we witnessing the beginning of the end of the nuclear era? Or beginning of a new one, glimpsed in the shade of authoritarian regimes?

  11. Risk reduction of core-melt accidents in advaned CAPRA burner cores

    International Nuclear Information System (INIS)

    Maschek, W.; Struwe, D.; Eigemann, M.

    1997-01-01

    As part of the CAPRA Program (Consommation Accrue de Plutonium dans les RApides) the feasibility of fast reactors is investigated to burn plutonium and also to destruct minor actinides. The design of CAPRA cores shows significant differences compared to conventional cores. Especially the high Pu-enrichment has an important influence on the core melt-down behavior and the associated recriticality risk. To cope with this risk, inherent design features and special measures/devices are investigated for their potential of early fuel discharge to reduce the criticality of the reactor core. An assessment of such measures/devices is given and experimental needs are formulated. 11 refs., 5 figs

  12. Analytic advanced development in the German Risk Study on Nuclear Power Plants

    International Nuclear Information System (INIS)

    1984-01-01

    The study carried out by the Ecological Institute (Oeko-Institut) deals with the difficulties encountered with the decision-making models and statistical models and methods of the German Risk Study on Nuclear Power Plants for the determination of care meltdown frequency and for the estimation of the behaviour of components in the event of a failure. Related deficiencies of the German Risk Study and the absence of completeness and lading representiveness of the course and causes of incidents considered are pointed out. The accident consequences model and the climatological-meteorological data base are considered non-representative. (RF) [de

  13. Behavior of a corium jet in high pressure melt ejection from a reactor pressure vessel

    International Nuclear Information System (INIS)

    Frid, W.E.

    1986-01-01

    A model has been developed to calculate the expansion and fragmentation of a corium jet, due to the evolution of dissolved gas, during a postulated core meltdown accident. Parametric calculations have been performed for a PWR high pressure accident scenario. Jet breakup occurs within a few jet diameters from the RPV. The diameter of the fragmented jet at the level of the reactor cavity floor is predicted to be 40-130 times the discharge diameter. Particles generated by fragmentation of corium melt are predicted to be in the 30-150 μm size range

  14. A consideration of low dose radiation effects on human health

    International Nuclear Information System (INIS)

    Shimada, Yoshiya; Nishimura, Mayumi; Imaoka, Tatsuhiko; Kakinuma, Shizuko

    2011-01-01

    On March 11, 2011, an earthquake categorized as 9 Mw occurred off the northeast coast of Japan. The subsequent destructive tsunami disabled emergency units of Fukushima Dai'ichi Nuclear Power Plant and caused partial meltdown of reactors and explosions. Resulting radiation releases forced large evacuations, bore concerns about food and water and fears against human health. In this manuscript, we described the effect of radiation, especially low dose radiation below 100 mSv, on cancer risk, focusing on fetuses and children. (author)

  15. Europe after Fukushima. German perspectives on the future of nuclear power

    Energy Technology Data Exchange (ETDEWEB)

    Temple, Samuel (ed.); Uekoetter, Frank [Muenchen Univ. (Germany). Rachel Carson Center for Environment and Society; Kersten, Jens [Munich Univ. (Germany). Chair of Public Law and Governance; Vogt, Markus [Munich Univ. (Germany). Chair in Christian Social Ehtics

    2012-07-01

    One year after the reactor meltdown at the Fukushima Daiichi Nuclear Power Station, this volume of RCC Perspectives takes stock of its impact and possible legacy in Europe as part of the Rachel Carson Center's research focus on natural disasters and cultures of risk. While Europe may have been spared radioactive fallout, political and cultural fallout has been significant. Are we witnessing the beginning of the end of the nuclear era? Or beginning of a new one, glimpsed in the shade of authoritarian regimes?.

  16. Safety analysis of RA reactor operation, I-III, Part III - Environmental effect of the maximum credible accident

    International Nuclear Information System (INIS)

    Raisic, N.

    1963-02-01

    Maximum credible accident at the RA reactor would consider release of fission products into the environment. This would result from fuel elements failure or meltdown due to loss of coolant. The analysis presented in this report assumes that the reactor was operating at nominal power at the moment of maximum possible accident. The report includes calculations of fission products activity at the moment of accident, total activity release during the accident, concentration of radioactive material in the air in the reactor neighbourhood, and the analysis of accident environmental effects

  17. Small scale studies of production of fissium aerosols

    International Nuclear Information System (INIS)

    Lindqvist, O.; Rydberg, J.

    1983-02-01

    A small scale study concerning the production and analysis of fission product aerosols formed at various temperatures as a function of the chemical composition of the fissium/corium mixture at the source is presented. CsOH, CsJ and Te are the main aerosol components to be expected. The thermodynamic characterization of occuring Te-iodides and other phases is of great importance for reactor core meltdown chemistry and for the evaluation of the aerosol transport tests. Elemental iodine seems not to be released in significant amounts in reducing atmosphere. Analysis data concerning elements, phases, themral analysis and gases are presented. (G.B.)

  18. What do we know more than 2012 on the accident progression in Fukushima? What is the actual state of the plant?; Was wissen wir heute mehr als 2012 ueber den Unfallablauf in Fukushima? Wie ist der heutige Zustand der Anlage?

    Energy Technology Data Exchange (ETDEWEB)

    Maqua, Michael [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Koeln (Germany)

    2015-06-01

    The contribution includes the official statistics on the accident following the earthquake and tsunami on March 11, 2011 on the Japanese island Honshu and the nuclear power plant Fukushima Daiichi. The plant was automatically shutdown as consequence of the earthquake. New calculations allow the reconstruction of the accident progress and the meltdown. Estimations of the released radioactivity, esp. the radionuclides I-131 and Cs-137 into the atmosphere and the ocean are summarized. The construction of water cleaning facilities for the contaminated waste water in the leaking tanks, water-tight barriers and the planning for the enclosure for the destroyed reactor buildings are described.

  19. The nature of reactor accidents

    International Nuclear Information System (INIS)

    Domaratzki, Z.; Campbell, F.R.; Atchison, R.J.

    1981-01-01

    Reactor accidents are events which result in the release of radioactive material from a nuclear power plant due to the failure of one or more critical components of that plant. The failures, depending on their number and type, can result in releases whose consequences range from negligible to catastrophic. By way of examples, this paper describes four specific accidents which cover this range of consequence: failure of a reactor control system, loss of coolant, loss of coolant with impaired containment, and reactor core meltdown. For each a possible sequence of events and an estimate of the expected frequency are presented

  20. Transient debris freezing and potential wall melting during a severe reactivity initiated accident experiment

    International Nuclear Information System (INIS)

    El-Genk, M.S.; Moore, R.L.

    1981-01-01

    It is important to light water reactor (LWR) safety analysis to understand the transient freezing of molten core debris on cold structures following a hypothetical core meltdown accident. The purpose of this paper is to (a) present the results of a severe reactivity initiated accident (RIA) in-pile experiment with regard to molten debris distribution and freezing following test fuel rod failure, (b) analyze the transient freezing of molten debris (primarily a mixture of UO/sub 2/ fuel and Zircaloy cladding) deposited on the inner surface of the test shroud wall upon rod failure, and (c) assess the potential for wall melting upon being contacted by the molten debris. 26 refs

  1. Major risks and financial guarantees provided by the State in France

    International Nuclear Information System (INIS)

    Brassard, Guy

    2012-01-01

    France's system for indemnifying damage from natural catastrophe is exemplary, whether for floods, storms, or subsidence. However, France is not equipped with the financial capacity to deal with the damage resulting from an exceptional disaster, such as an earthquake on the Mediterranean coast, or a nuclear meltdown. Major catastrophes could be a significant risk to the financial stability of the State today, because the State is in fact the ultimate insurer of its citizens and its institutions. It would be wise to built up reserves in order to enhance the financial resources of the State and to provide a uniform guarantee covering major risks, whatever the cause of the damage may be. (author)

  2. Studies on melt-water-structure interaction during severe accidents

    International Nuclear Information System (INIS)

    Sehgal, B.R.; Dinh, T.N.; Okkonen, T.J.; Bui, V.A.; Nourgaliev, R.R.; Andersson, J.

    1996-10-01

    Results of a series of studies, on melt-water-structure interactions which occur during the progression of a core melt-down accident, are described. The emphasis is on the in-vessel interactions and the studies are both experimental and analytical. Since, the studies performed resulted in papers published in proceedings of the technical meetings, and in journals, copies of a set of selected papers are attached to provide details. A summary of the results obtained is provided for the reader who does not, or cannot, venture into the perusal of the attached papers. (au)

  3. Considerations concerning the strategy of corium retention in the reactor vessel

    International Nuclear Information System (INIS)

    2015-01-01

    Third-generation nuclear reactors are characterised by consideration during design of core meltdown accidents. More specifically, dedicated measures or devices must be implemented to avoid basemat melt-through in the reactor building. These devices must have a high level of confidence. The strategy of corium retention in the reactor vessel, if supported by appropriate research and development, makes it possible to achieve this objective. IRSN works alone or in partnerships to address all the issues associated with in-vessel corium retention. This document describes the in-vessel corium retention strategy and its limitations, along with the research programs conducted by IRSN in this area

  4. First evaluation of experimental results describing pressure buildup and hydrogen distribution, obtained by experimental series E11

    International Nuclear Information System (INIS)

    Holzbauer, H.; Wolf, L.; Valencia, L.

    1990-01-01

    The beginning of the core meltdown process in the reactor pressure vessel, with a supposed release position for hydrogen in the upper part of the containment, is simulated, and the influence of the plant geometry on the distribution process is studied. In addition, the release point is shifted to the lower containment area, additional hydrogen production owing to the interaction between concrete and melt is taken into account, and sump boiling is simulated. The experimental program covers analytical investigations in the form of blind post-calculations. (DG) [de

  5. Business models and people management in the Indian IT industry from people to profits

    CERN Document Server

    Malik, Ashish

    2015-01-01

    The global impact of so-called 'offshoring', including of information technology (IT) and related services, continues to be a topic of great interest to academics, practitioners and policy makers. The Indian IT industry has sustained high levels of growth in revenues and employment since the late 1980s. Even following the global financial crisis and meltdown in 2008, the industry has reported growth, albeit at a lower rate. Furthermore, the high rates of technological change and increased competition has forced businesses and managers to be innovative and create new business models.

  6. Studies on melt-water-structure interaction during severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Dinh, T.N.; Okkonen, T.J.; Bui, V.A.; Nourgaliev, R.R.; Andersson, J. [Royal Inst. of Technology, Div. of Nucl. Power Safety, Stockholm (Sweden)

    1996-10-01

    Results of a series of studies, on melt-water-structure interactions which occur during the progression of a core melt-down accident, are described. The emphasis is on the in-vessel interactions and the studies are both experimental and analytical. Since, the studies performed resulted in papers published in proceedings of the technical meetings, and in journals, copies of a set of selected papers are attached to provide details. A summary of the results obtained is provided for the reader who does not, or cannot, venture into the perusal of the attached papers. (au).

  7. GLOBAL ECONOMIC CRISIS: A VIEW FROM SOUTH AFRICA

    Directory of Open Access Journals (Sweden)

    Patrick Bond

    2015-08-01

    Full Text Available Any analysis of the erratic unfolding of global economic crisis is bound to be hotly contested. This is particularly so in mid-1999, amid claims from Washington that the past two years' dangers of financial meltdown and deflation were averted and finally extinguished through a combination of policy measures and good fortune: slightly looser Federal Reserve monetary policy adopted in September 1998, in the immediate wake of the successful public-private bailout of the Long Term Capital Management hedge fund; a new $90 billion International Monetary Fund (IMF insurance scheme announced the following month; the convening of key countries in a Forum on Financial Stability; the lack of financial contagion (contrary to expectations in the wake of Brazil's January 1999 currency meltdown; the long-awaited revival (however infirm of the Japanese economy; new plans for somewhat more transparent budgetary and exchange rate systems in emerging markets; and a decision at the G-8 Cologne meeting in June 1999 to sell 10% of the IMF's gold to fund partial debt relief for the poorest Third World countries. Indeed many observers were surprised at IMF Managing Director Michel Camdessus's success at turning the debt relief strategy into a vehicle for tougher "Enhanced Structural Adjustment Facility" conditions, just months after the IMF was criticised to the point of ridicule for its East Asian, Russian and Brazilian mishaps (effectively, granting $200 billion in bad loans over 15 months, in exchange for the application of inappropriate austerity measures.

  8. Phenomena in the interaction among a core melt and protective and sacrificial materials

    International Nuclear Information System (INIS)

    Steinwarz, W.; Koller, W.; Dyllong, N.; Fischer, M.; Hellmann, S.; Lansmann, V.; Nie, M.; Haefner, W.; Alkan, Z.; Andrae, P.; Rensing, B.

    2000-01-01

    In a postulated core meltdown accident in a light water reactor there are bound to be interactions, in the ex-vessel phase, among the core melt and the structural materials within and below the reactor cavity. In existing plants, these structural materials normally are structural concrete, while future, evolutionary reactor lines are to have sacrificial and protective materials specially designed for this hypothetical case. To add to the state of knowledge about the phenomena occurring, experiments need to be conducted under conditions as realistic as possible. Within the research programs funded by the European Union, the German Federal Ministry for Economics, and the German nuclear power plant operators, experiments on a laboratory as well as an industrial scale on these problems are being carried out in the two projects called CORESA (COrium on REfractory and SAcrificial materials) and ECOSTAR (Ex-vessel COre melt STAbilization Research). The experiments are accompanied by an extensive analytical theoretical program also serving to advance and validate computer codes on the problems under investigation. The projects, which are carried out with international European participation, are expected to allow a concept to be developed for managing postulated accident scenarios involving core meltdown for innovative nuclear power plants, and to provide findings on risk evaluation of plants now in operation so as to further develop accident management measures. (orig.) [de

  9. Melt propagation in dry core debris beds

    International Nuclear Information System (INIS)

    Dosanjh, S.S.

    1989-01-01

    During severe light water reactor accidents like Three Mile Island Unit 2, the fuel rods can fragment and thus convert the reactor core into a large particle bed. The postdryout meltdown of such debris beds is examined. A two-dimensional model that considers the presence of oxidic (UO 2 and ZrO 2 ) as well as metallic (e.g., zirconium) constituents is developed. Key results are that a dense metallic crust is created near the bottom of the bed as molten materials flow downward and freeze; liquid accumulates above the blockage and, if zirconium is present, the pool grows rapidly as molten zirconium dissolved both UO 2 and ZrO 2 particles; if the melt wets the solid, a fraction of the melt flows radially outward under the action of capillary forces and freezes near the radial boundary; in a nonwetting system, all of the melt flows into the bottom of the bed; and when zirconium and iron are in intimate contact and the zirconium metal atomic fraction is > 0.33, these metals can liquefy and flow out of the bed very early in the meltdown sequence

  10. Treatment of EBR-I NaK mixed waste at Argonne National Laboratory and subsequent land disposal at the Idaho National Engineering and Environmental Laboratory

    International Nuclear Information System (INIS)

    Herrmann, S. D.; Buzzell, J. A.; Holzemer, M. J.

    1998-01-01

    Sodium/potassium (NaK) liquid metal coolant, contaminated with fission products from the core meltdown of Experimental Breeder Reactor I (EBR-I) and classified as a mixed waste, has been deactivated and converted to a contact-handled, low-level waste at Argonne's Sodium Component Maintenance Shop and land disposed at the Radioactive Waste Management Complex. Treatment of the EBR-I NaK involved converting the sodium and potassium to its respective hydroxide via reaction with air and water, followed by conversion to its respective carbonate via reaction with carbon dioxide. The resultant aqueous carbonate solution was solidified in 55-gallon drums. Challenges in the NaK treatment involved processing a mixed waste which was incompletely characterized and difficult to handle. The NaK was highly radioactive, i.e. up to 4.5 R/hr on contact with the mixed waste drums. In addition, the potential existed for plutonium and toxic characteristic metals to be present in the NaK, resultant from the location of the partial core meltdown of EBR-I in 1955. Moreover, the NaK was susceptible to degradation after more than 40 years of storage in unmonitored conditions. Such degradation raised the possibility of energetic exothermic reactions between the liquid NaK and its crust, which could have consisted of potassium superoxide as well as hydrated sodium/potassium hydroxides

  11. Treatment of EBR-I NaK mixed waste at Argonne National Laboratory and subsequent land disposal at the Idaho National Engineering and Environmental Laboratory.

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, S. D.; Buzzell, J. A.; Holzemer, M. J.

    1998-02-03

    Sodium/potassium (NaK) liquid metal coolant, contaminated with fission products from the core meltdown of Experimental Breeder Reactor I (EBR-I) and classified as a mixed waste, has been deactivated and converted to a contact-handled, low-level waste at Argonne's Sodium Component Maintenance Shop and land disposed at the Radioactive Waste Management Complex. Treatment of the EBR-I NaK involved converting the sodium and potassium to its respective hydroxide via reaction with air and water, followed by conversion to its respective carbonate via reaction with carbon dioxide. The resultant aqueous carbonate solution was solidified in 55-gallon drums. Challenges in the NaK treatment involved processing a mixed waste which was incompletely characterized and difficult to handle. The NaK was highly radioactive, i.e. up to 4.5 R/hr on contact with the mixed waste drums. In addition, the potential existed for plutonium and toxic characteristic metals to be present in the NaK, resultant from the location of the partial core meltdown of EBR-I in 1955. Moreover, the NaK was susceptible to degradation after more than 40 years of storage in unmonitored conditions. Such degradation raised the possibility of energetic exothermic reactions between the liquid NaK and its crust, which could have consisted of potassium superoxide as well as hydrated sodium/potassium hydroxides.

  12. Atucha I nuclear power plant: Probabilistic safety study. Loss-of-coolant accidents

    International Nuclear Information System (INIS)

    Perez, S.S.

    1987-01-01

    The plant response to the group of events 'large coolant loss' in order to evaluate the associated risk is analyzed. The event that covers all events of similar sequence due to its evolution features, being also the most demanded, is selected as starting event. The representative event is the 'guillotine type rupture of cold primary branch'. An annual occurrence frequency of 10/year is assumed for this event. The safety systems, when the event occurs, must assure the reactor shutdown and the core cooling, creating a heat sink to remove the decay heat. The annual frequency of core meltdown due to great loss of coolant is obtained multiplying the annual frequency of the starting event by the probability of failure of involved safety systems. By means of failure trees, the following is obtained: a) probability of failure to demand of the boron injection shutdown system = 4 x 10 -2 ; b) probability of failure to demand of the high pressure safety injection = 3 x 10 -3 ; c) probability of emergency cooling system failure = 4.4 x 10 -2 . Therefore, the three possible sequences of core meltdown have the following frequencies: λ 1 = 4 x 10 -6 /year λ 2 = 3 x 10 -7 /year λ 3 = 4.4 x 10 -6 /year. (Author)

  13. Preventing another Chernobyl: codes, practices, and the role of new technology

    International Nuclear Information System (INIS)

    Egan, J.R.

    1988-01-01

    Preventative steps to prevent and mitigate the consequences of a nuclear accident are considered. The national and international legislation now available is mentioned elsewhere in the book. This chapter discusses the role of codes of conduct and personal agreements which could also prevent nuclear accidents. It is suggested that a radical departure from existing nuclear technology is needed. In particular some definite goals and objectives are suggested. The first is that there should be no meltdowns - all reactors must be physically incapable of core meltdown or explosion under any circumstances. This would mean no huge emergency evacuation plans, no need for expensive emergency core cooling systems. No spiralling cost overruns, no nuclear waste problem, no more huge reactors too big for national electrical systems, no military complications, no intractable decommissionings and no quality control problems are also given as goals. Some of these goals could be achieved with inherently safe reactor designs, much smaller reactors and factory assembly, rather than on-site construction. Other suggestions are also made to achieve the proposed new nuclear technology. (U.K.)

  14. Steam explosion - physical foundations and relation to nuclear reactor safety

    International Nuclear Information System (INIS)

    Schumann, U.

    1982-08-01

    'Steam explosion' means the sudden evaporation of a fluid by heat exchange with a hotter material. Other terms are 'vapour explosion', 'thermal explosion', and 'energetic fuel-coolant interaction (FCI)'. In such an event a large fraction of the thermal energy initially stored in the hot material may possibly be converted into mechanical work. For pressurized water reactors one discusses (e.g. in risk analysis studies) a core melt-down accident during which molten fuel comes into contact with water. In the analysis of the consequences one has to investigate steam explosions. In this report an overview over the state of the knowledge is given. The overview is based on an extensive literature review. The objective of the report is to provide the basic knowledge which is required for understanding of the most important theories on the process of steam explosions. Following topics are treated: overview on steam explosion incidents, work potential, spontaneous nucleation, concept of detonation, results of some typical experiments, hydrodynamic fragmentation of drops, bubbles and jets, coarse mixtures, film-boiling, scenario of a core melt-down accident with possible steam-explosion in a pressurized water reactor. (orig.) [de

  15. Lessons learned from first generation nuclear plant probabalistic risk assessments

    International Nuclear Information System (INIS)

    Garrick, B.J.

    1984-01-01

    The paper by Garrick summarizes the state-of-the-art in what are perhaps the most archetypical probabilistic risk assessments (PRAs). Because of its unique regulatory environment and because of the high levels of perceived (not necessarily actual) risk, the nuclear industry more than any other has been concerned with quantitative risk analysis. Garrick's paper summarizes the lessons learned from ten PRA's conducted in the nuclear industry, including six that can be characterized as full-scope risk studies. Most of the quantitative data, though, came from two especially thorough studies done for the Zion and Indian Point power plants, operated by Commonwealth Edison and Consolidated Edison respectively. The principal conclusions of the Garrick survey are that the public risk (from radiation release) is now known to be very small for commercial nuclear power plants, but that the risk to utilities (from core damage) is somewhat larger. Significant radiation releases require both core meltdown -- an event occurring only about once every 10,000 reactor-years -- and containment failure, occurring only about once in every hundred meltdowns

  16. Reactors at sea

    International Nuclear Information System (INIS)

    Hines, Colin

    1988-01-01

    The Greenpeace Nuclear Free Seas Campaign is outlined. The campaign aims to bring the environmental hazards from nuclear submarines and naval ships carrying nuclear weapons to public attention. Worldwide there are 544 nuclear reactor ships or submarines each with the potential to meltdown with serious environmental consequences. One meltdown is known to have occurred. Five reactors have been abandoned on the sea bed. Nuclear powered submarines are based at Rosyth, Faslane, Holy Loch, Plymouth and Portsmouth and routinely come into and out of those harbours. There have also been accidents involving nuclear weapons on board submarines, aircraft carriers or destroyers which carry nuclear depth bombs and free fall bombs. The Royal Navy's accident emergency plans for nuclear naval bases are inadequate. There is a threat to the environment when the reactors are decommissioned. There are no clear plans as to how to deal with the decommissioning of the submarines or ships although the fuel rods have been removed from the first British nuclear submarine, Dreadnought. (U.K.)

  17. MELMRK 2.0: A description of computer models and results of code testing

    International Nuclear Information System (INIS)

    Wittman, R.S.; Denny, V.; Mertol, A.

    1992-01-01

    An advanced version of the MELMRK computer code has been developed that provides detailed models for conservation of mass, momentum, and thermal energy within relocating streams of molten metallics during meltdown of Savannah River Site (SRS) reactor assemblies. In addition to a mechanistic treatment of transport phenomena within a relocating stream, MELMRK 2.0 retains the MOD1 capability for real-time coupling of the in-depth thermal response of participating assembly heat structure and, further, augments this capability with models for self-heating of relocating melt owing to steam oxidation of metallics and fission product decay power. As was the case for MELMRK 1.0, the MOD2 version offers state-of-the-art numerics for solving coupled sets of nonlinear differential equations. Principal features include application of multi-dimensional Newton-Raphson techniques to accelerate convergence behavior and direct matrix inversion to advance primitive variables from one iterate to the next. Additionally, MELMRK 2.0 provides logical event flags for managing the broad range of code options available for treating such features as (1) coexisting flow regimes, (2) dynamic transitions between flow regimes, and (3) linkages between heatup and relocation code modules. The purpose of this report is to provide a detailed description of the MELMRK 2.0 computer models for melt relocation. Also included are illustrative results for code testing, as well as an integrated calculation for meltdown of a Mark 31a assembly

  18. The potential application of rice bran wax oleogel to replace solid fat and enhance unsaturated fat content in ice cream.

    Science.gov (United States)

    Zulim Botega, Daniele C; Marangoni, Alejandro G; Smith, Alexandra K; Goff, H Douglas

    2013-09-01

    The development of structure in ice cream, characterized by its smooth texture and resistance to collapse during melting, depends, in part, on the presence of solid fat during the whipping and freezing steps. The objective of this study was to investigate the potential application of 10% rice bran wax (RBW) oleogel, comprised 90% high-oleic sunflower oil and 10% RBW, to replace solid fat in ice cream. A commercial blend of 80% saturated mono- and diglycerides and 20% polysorbate 80 was used as the emulsifier. Standard ice cream measurements, cryo-scanning electron microscopy (cryo-SEM), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) were used to evaluate the formation of structure in ice cream. RBW oleogel produced higher levels of overrun when compared to a liquid oil ice cream sample, creating a lighter sample with good texture and appearance. However, those results were not associated with higher meltdown resistance. Microscopy revealed larger aggregation of RBW oleogel fat droplets at the air cell interface and distortion of the shape of air cells and fat droplets. Although the RBW oleogel did not develop sufficient structure in ice cream to maintain shape during meltdown when a mono- and diglycerides and polysorbate 80 blend was used as the emulsifier, micro- and ultrastructure investigations suggested that RBW oleogel did induce formation of a fat globule network in ice cream, suggesting that further optimization could lead to an alternative to saturated fat sources for ice cream applications. © 2013 Institute of Food Technologists®

  19. MELPROG/TRAC: update and applications

    International Nuclear Information System (INIS)

    Henninger, R.J.; Kelly, J.E.

    1986-01-01

    The first complete, coupled, and mechanistic analysis of a core meltdown sequence has been made with MELPROG-PWR/MOD1 and MELPROG/TRAC. The sequence analyzed was a station blackout accident for the Surry plant. Through vessel failure, all important aspects of the meltdown sequence were calculated. This version of MELPROG permits a full two-dimensional treatment of the in-vessel phenomena. Natural circulation can thus be modeled. Comparison to one-dimensional MELPROG and MARCH calculations shows that natural circulation reduces the rate of core heating, but increases the rate of heating of upper plenum structures and primary piping. This increased heating can inhibit fission product deposition and may lead to an early failure of the primary system. Because of uncertainty, sensitivity studies were performed to assess the relative importance of modeling assumptions. Changes in the modeling of the initial fuel rod melting and relocation were found to vary the hydrogen source by a factor of 2 and alter the timing of key events. These results imply that accurate and mechanistic modeling is important for severe accident sequence analysis

  20. Uranium Dioxides and Debris Fragments Released to the Environment with Cesium-Rich Microparticles from the Fukushima Daiichi Nuclear Power Plant.

    Science.gov (United States)

    Ochiai, Asumi; Imoto, Junpei; Suetake, Mizuki; Komiya, Tatsuki; Furuki, Genki; Ikehara, Ryohei; Yamasaki, Shinya; Law, Gareth T W; Ohnuki, Toshihiko; Grambow, Bernd; Ewing, Rodney C; Utsunomiya, Satoshi

    2018-03-06

    Trace U was released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) during the meltdowns, but the speciation of the released components of the nuclear fuel remains unknown. We report, for the first time, the atomic-scale characteristics of nanofragments of the nuclear fuels that were released from the FDNPP into the environment. Nanofragments of an intrinsic U-phase were discovered to be closely associated with radioactive cesium-rich microparticles (CsMPs) in paddy soils collected ∼4 km from the FDNPP. The nanoscale fuel fragments were either encapsulated by or attached to CsMPs and occurred in two different forms: (i) UO 2+X nanocrystals of ∼70 nm size, which are embedded into magnetite associated with Tc and Mo on the surface and (ii) Isometric (U,Zr)O 2+X nanocrystals of ∼200 nm size, with the U/(U+Zr) molar ratio ranging from 0.14 to 0.91, with intrinsic pores (∼6 nm), indicating the entrapment of vapors or fission-product gases during crystallization. These results document the heterogeneous physical and chemical properties of debris at the nanoscale, which is a mixture of melted fuel and reactor materials, reflecting the complex thermal processes within the FDNPP reactor during meltdown. Still CsMPs are an important medium for the transport of debris fragments into the environment in a respirable form.

  1. Poison and diluent system for nuclear power plants

    International Nuclear Information System (INIS)

    Parker, W.G.; Ravets, J.M.; Preble, B.S.

    1978-01-01

    A system to prevent supercriticality in nuclear power plants in the unlikely event of a core destructive accident terminating in the nuclear core meltdown is described. The system dilutes and poisons the molten core to maintain subcriticality, and is useful in mobile nuclear power plants, or in nuclear plants subject to seismic disturbances, where the orientation of the nuclear reactor after the accident is unknown. It is also applicable to alleviate the consequences of loss of coolant flow accidents from any cause. Aside from preventing supercriticality, the system serves the dual purpose of acting as a biological shield and/or structural member that reduces the deleterious effects of accidental core impaction, without compromising power plant weight and size constraints. A borated material, with a melting point greater than the fuel melting point, is inserted in the pressure vessel behind an inner wall. In the unlikely event of a core meltdown, the molten fuel melts through the inner wall and is diluted and poisoned by the borated material. In the event the molten fuel melts through the pressure vessel, additional borated material is provided to continue diluting and poisoning

  2. Teaching of severe accident of Fukushima Daiichi Nuclear Power Plants of Tokyo Electric Power

    International Nuclear Information System (INIS)

    Saito, Shinzo

    2011-01-01

    The Great East Japan Earthquake and accompanied tsunami brought about the severe accident at Fukushima Daiichi Nuclear Power Plants of Tokyo Electric Power Co., Inc. For 'No more Fukushima', twelve teaching of the accident was pointed out as follows: 1) natural disasters and external events shall be taken into consideration, 2) severe accident shall be included into safety regulation, 3) all possibility of hydrogen explosion shall be excluded, 4) diversity of safety important component and equipment shall be added with sufficient period of outage, 5) siting of multiple units at the same site shall be avoided at quake-prone country like Japan, 6) accident response environment for operators shall be improved, 7) accident convergence termination system shall be established so as to concentrate technical experience and knowledge, 8) off-site center shall be improved, 9) resident evacuation, consumption limit of food, radiation exposure and soil contamination limit shall be decided openly, 10) nuclear regulation and prevention of disaster shall be conducted by unitary organization to gain public trust, 11) fostering of safety culture among relevant enterprises shall be more encouraged and 12) nuclear industry shall develop reactor such as with no core meltdown or no evacuation and environmental contamination even if reactor core would be meltdown. (T. Tanaka)

  3. Standards and guidelines should be rules between licensees and regulators

    International Nuclear Information System (INIS)

    Narabayashi, Tadashi

    2014-01-01

    The 2011 off the Pacific coast of Tohoku Pacific Earthquake and the Tsunami gave the serious damage to the Fukushima-Daiichi Nuclear Power Plants (NPPs). The accidents occurred in Unit 1, 2, 3 and 4. It is said that the height of tsunami attacked Fukushima NPP was more than 14m. After 50 minutes from the automatic shut-down, tsunami attacked the NPPs in Fukushima Daiichi NPPs. For example, the Unit 1 lost A/C power caused the loss of water injection function; it made the core meltdown and unusual increase of PCV pressure in the midnight of March 11th to 12th morning. Though the Unit one has the Isolation Condenser Core Cooling system, it was stopped by the operator to keep the cooling rate of 55degC/h. Finally, the isolation signal was transmitted from the control room to the motor driven isolation valves when the control room's battery discharged. It was the initiation of the core meltdown. The lessons from the accidents, we should improve the nuclear safety regulation through the innovation of regulatory rules and safety standards. Standards and guidelines should be rules between licensees and regulators. (author)

  4. A status report on the integral fast reactor fuels and safety program

    International Nuclear Information System (INIS)

    Pedersen, D.R.; Seidel, B.R.

    1990-01-01

    The integral fast reactor (IFR) is an advanced liquid-metal-cooled reactor (ALMR) concept being developed at Argonne National Laboratory. The IFR program is specifically responsible for the irradiation performance, advanced core design, safety analysis, and development of the fuel cycle for the US Department of Energy's ALMR program. The basic elements of the IFR concept are (a) metallic fuel, (b) liquid-sodium cooling, (c) modular, pool-type reactor configuration, (d) an integral fuel cycle based upon pyrometallurgical processing. The most significant safety aspects of the IFR program result from its unique fuel design, a ternary alloy of uranium, plutonium, and zirconium. This fuel is based on experience gained through > 25 yr operation of the Experimental Breeder Reactor II (EBR-II) with a uranium alloy metallic fuel. The ultimate criteria for fuel pin design is the overall integrity at the target burnup. The probability of core meltdown is remote; however, a theoretical possibility of core meltdown remains. The next major step in the IFR development program will be a full-scale pyroprocessing demonstration to be carried out in conjunction with EBR-II. The IFR fuel cycle closure based on pyroprocessing will also have a dramatic impact on waste management options and on actinide recycling

  5. Decision No. 2008-DC-0114 of 26 September 2008 by the French Nuclear Safety Authority Setting Forth Specific Requirements to Be Met by Electricite de France - Societe anonyme (EDF-SA) at the Flamanville Nuclear site Regarding the Design and Construction of the Flamanville-3 (INB No. 167) NPP and the Operation of Flamanville-1 (INB No. 108) and Flamanville-2 (INB No. 109) NPPs

    International Nuclear Information System (INIS)

    2009-01-01

    This decision sets forth the requirements to be met by Electricite de France (EDF-SA), the operator, regarding the design and construction of Basic Nuclear Installation ('installation nucleaire de base' - INB) No. 167 and the operation of INBs Nos. 108 and 109 on the Flamanville Site, Manche Department. The specific requirements applicable to INB No. 167 (Flamanville-3) are described in Annex 1. Common requirements applicable to INBs Nos. 167 (Flamanville 3), 108 (Flamanville 1) and 109 (Flamanville 2) are described in Annex 2. Content of the annex 1 (Requirements applicable to INB No. 167 - Flamanville-3): Organisation and management: Organisation and management, Operations to be declared to or approved by ASN; Accident-risk management: Process control (Nuclear safety demonstration, Compliance of operations, Analysis of internal and external hazards leading to hostile conditions or damages to structures, systems and components, Analysis of hazards caused by the environment of the installation that may induced hostile conditions or damages to structures, systems and components, Probabilistic studies, Specific studies, Environmental qualification of systems, equipment, material and components, Controls or tests performed to comply with the hypotheses used in safety demonstration); Prevention of accident conditions that may lead to large early releases (Core-meltdown situations occurring while the primary circuit is at high pressure, Fuel-meltdown situations in the spent-fuel cooling pool, Reactivity accidents resulting from the rapid introduction in the primary circuit of cold water or of water with an insufficient concentration of soluble neutron absorber, Core-meltdown situations with containment bypass, Global hydrogen detonations and steam explosions likely to compromise the integrity of the reactor containment), Basic nuclear safety functions of the installation (Common provisions, Reactivity control, Cooling of nuclear fuel, Containment of radioactive

  6. Der Vision atomtechnischer Verheißungen gefolgt: Von der Euphorie zu ersten Protesten – die zivile Nutzung der Kernkraft in Deutschland seit den 1950er Jahren

    Directory of Open Access Journals (Sweden)

    Gleitsmann, Rolf-Jürgen

    2011-04-01

    Full Text Available In the 1950s, the nuclear age was announced and propagated worldwide as a future blessing for mankind. “Atoms for peace” was the promising slogan, indicating that Western industrial nations denying the atomic salvation would be seriously threatening their own and the whole West’s economic prosperity. West Germany heavily embraced this technological utopia and relied on the development of nuclear technology since the 1950s. Despite continuous grassroot protest especially in West Germany, this resulted in a path dependency of a technical momentum (Thomas P. Hughes in the system of the large-scale energy production until today, which only might have come to an end as a result of Fukushima’s super meltdown.

  7. Volume reduction options for the management of low-level radioactive wastes

    International Nuclear Information System (INIS)

    Clark, D.E.; Lerch, R.E.

    1977-01-01

    This paper examines volume reduction options that are now or soon will be available for low-level wastes. These wastes generally are in the form of combustible solids, noncombustible solids, and wet wastes (solid/liquid). Initially, the wastes are collected and stored onsite. Preconditioning may be required, e.g., sorting, shredding, and classifying the solids into combustible and noncombustible fractions. The volume of combustible solids can be reduced by compaction, incineration/pyrolysis, acid digestion, or molten salt combustion. Options for reducing the volume of noncombustible solids include compaction, size reduction and decontamination, meltdown-casting, dissolution and electropolishing. Burnable wet wastes (e.g., organic wastes) can be evaporated or combusted; nonburnable wet wastes can be treated by various evaporative or nonevaporative processes. All radioactive waste processing operations result in some equipment contamination and the production of additional radioactively contaminated wastes (secondary wastes). 23 figures

  8. Next nuclear gamble: transportation and storage of nuclear waste

    International Nuclear Information System (INIS)

    Resnikoff, M.

    1983-01-01

    Accidents during transport of nuclear waste are more threatening - though less likely - than a reactor meltdown because transportation accidents could occur in the middle of a populous city, affecting more people and property than a plant accident, according to the Council on Economic Priorities, a non-profit public service research organization. Transportation, as presently practiced, is unsafe. Shipping containers, called casks, are poorly designed and constructed, CEP says. The problem needs attention because the number of casks filled with nuclear waste on the nation's highways could increase a hundred times during the next 15 years under the Nuclear Waste Policy Act of 1982, which calls for storage areas. Recommendations, both technical and regulatory, for reducing the risks are presented

  9. LSA Large Area Silicon Sheet Task Continuous Liquid Feed Czochralski Growth

    Science.gov (United States)

    Fiegl, G.

    1979-01-01

    A process for the continuous growth of crystals by the Czochralski method, suitable for producing single silicon crystals for use in solar cells was studied. Continuous growth is the growth of 100 Kg of single silicon crystals, 10 cm in diameter, from one container. A furnace with continuous liquid replenishment of the growth crucible, accomplished by a melt-down system and a liquid transfer mechanism, with associated automatic feedback controls was developed. Elements of the transfer system were further developed and tested during actual transfer runs. Considerable simplification of the heating element of the transfer tube was achieved. Accuracy and reliability of the temperature sensor, which is part of the power input control system for the transfer tube, was improved. Electrical and thermal effectiveness were increased while assembly of the transfer tube system was further simplified.

  10. Reactor containment depressurization and filtration equipment for use in the case of a serious accident

    International Nuclear Information System (INIS)

    L'Homme, A.

    1987-06-01

    A study was carried out under the aegis of the OECD into filtered vented containment systems which permit depressurization of the containment and filtration of the effluents released to the environment, in the event of a major accident with a pressurized water reactor (PWR) (or BWR or CANDU type reactors) involving core meltdown, with a view to minimizing the consequences. This paper describes the various systems examined which could possibly be used for this purpose. These comprised the French robust sand filtration system, the Swedish FILTRA system, the vacuum containment and discharge and emergency filtration system used by the CANDU plants of the Ontario-Hydro electricity company in Canada and the BWR pressure-suppression pounds. The positions of the various national authorities regarding incorporation of such systems into nuclear power plants, the design and technical principles underlying the systems, the procedures and criteria for their use and their advantages and disadvantages are examined [fr

  11. Fukushima Daiichi Radionuclide Inventories

    Energy Technology Data Exchange (ETDEWEB)

    Cardoni, Jeffrey N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jankovsky, Zachary Kyle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-09-01

    Radionuclide inventories are generated to permit detailed analyses of the Fukushima Daiichi meltdowns. This is necessary information for severe accident calculations, dose calculations, and source term and consequence analyses. Inventories are calculated using SCALE6 and compared to values predicted by international researchers supporting the OECD/NEA's Benchmark Study on the Accident at Fukushima Daiichi Nuclear Power Station (BSAF). Both sets of inventory information are acceptable for best-estimate analyses of the Fukushima reactors. Consistent nuclear information for severe accident codes, including radionuclide class masses and core decay powers, are also derived from the SCALE6 analyses. Key nuclide activity ratios are calculated as functions of burnup and nuclear data in order to explore the utility for nuclear forensics and support future decommissioning efforts.

  12. Uscire dalla crisi finanziaria statunitense: la politica domina l’economia nella Nuova Economia Politica

    Directory of Open Access Journals (Sweden)

    JAN KREGEL

    2011-01-01

    Full Text Available Most economists expected that the “Great Recession” produced by the financial meltdown of 2008 would usher in a resurgence of traditional Keynesian economics and a decline of what has come to be called “market fundamentalism”. By contrast, also due to the inadequate size of the 2009 stimulus package, the resurgence of support for Keynesian expenditure policies has been extremely short lived. However, the negative popular and political reaction should not have come as a surprise, at least for three reasons: the design of the Obama stimulus plan and its difference from the expenditure policies of the Roosevelt Administration; the political environment that has eviscerated fiscal policy and placed monetary policy at the centre of economic policy and produced “debt driven” growth; the difference between policies appropriate to treating an income deflation and a debt deflation.

  13. Limitations of the government budget constraint: Users vs. issuers of the currency

    Directory of Open Access Journals (Sweden)

    Kelton Stephanie

    2011-01-01

    Full Text Available The financial crisis and ensuing economic meltdown has led to sharp increases in the deficits and debt levels of many advanced economies. The run-up in public sector indebtedness helped to restore private sector balance sheets, laying the foundation for economic recovery in these regions. But the so-called “sovereign” debt crisis in the Eurozone has undermined the fiscal resolve that has, thus far, kept truly sovereign governments from slipping into a bona fide depression. Fearful of becoming the next Greece, governments that could allow an unlimited fiscal adjustment to restore full employment, are methodically weakening their fiscal support mechanisms and setting themselves on a path to becoming the next Japan.

  14. Investigation of the different scenarios occurring in a PWR in case of a TMLB accident

    International Nuclear Information System (INIS)

    Pochard, R.; Dufresne, J.; Autrusson, B.

    1988-10-01

    Severe accidents in light water reactors fall into one of two main categories, depending on whether or not core meltdown is accompanied by a pressure buildup in the primary system. The way in which the accident develops is, in fact, largely conditioned by this pressure aspect: temperature distribution in the core and primary system resulting from natural convection gas streams; fuel clad failure mode, etc... One major effect of pressure buildup on the accident scenario is primary system failure under the combined actions of pressure and temperature. The purpose of the present paper is to present, after a detailed thermalhydraulic study, an analysis of the timing and location of the system failures in case of a TMLB accident on CPY french type reactor

  15. Urban agriculture in Botswana

    Directory of Open Access Journals (Sweden)

    Aloysius Clemence Mosha

    2016-02-01

    Full Text Available Botswana, a middle-income country, is experiencing a sluggish economic growth and a rapid urbanisation which has brought in its wake high unemployment, poverty and food insecurity. This has led some people to engage in subsistence and commercial urban and peri-urban agriculture (UPA to address these problems. However, in spite of its known advantages, uptake of UPA has been low for a number of reasons including: high GDP before the economic meltdown of recent years; a harsh climate; lack of water; poor access to land; and over-reliance on generous government handouts. Nevertheless, the extent of its practice and its contribution to food security – albeit modest – shows that it is a sector that needs to be encouraged and supported. Both central and local government can play a big role by providing land and infrastructure, and also by implementing an enabling policy and regulatory environment which promotes small- and medium-scale urban food production.

  16. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Lap-Yan, C.; Wie, T. Y. C.

    2009-01-01

    The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs) is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR) in a GEN IV direct-cycle gas-cooled fast reactor (GFR) which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  17. Simulating single-event burnout of n-channel power MOSFET's

    International Nuclear Information System (INIS)

    Johnson, G.H.; Hohl, J.H.; Schrimpf, R.D.; Galloway, K.F.

    1993-01-01

    Heavy ions are ubiquitous in a space environment. Single-event burnout of power MOSFET's is a sudden catastrophic failure mechanism that is initiated by the passage of a heavy ion through the device structure. The passage of the heavy ion generates a current filament that locally turns on a parasitic n-p-n transistor inherent to the power MOSFET. Subsequent high currents and high voltage in the device induce second breakdown of the parasitic bipolar transistor and hence meltdown of the device. This paper presents a model that can be used for simulating the burnout mechanism in order to gain insight into the significant device parameters that most influence the single-event burnout susceptibility of n-channel power MOSFET's

  18. Investigation: revelations about Three Mile Island disaster raise doubts over nuclear plant safety: a special facing south investigation by Sue Sturgis.

    Science.gov (United States)

    Sturgis, Sue

    2009-01-01

    A series of mishaps in a reactor at the Three Mile Island (TMI) nuclear plant led to the 1979 meltdown of almost half the uranium fuel and uncontrolled releases of radiation into the air and surrounding Susquehanna River. It was the single worst disaster ever to befall the U.S. nuclear power industry. Health physics technician Randall Thompson's story about what he witnessed while monitoring radiation there after the incident is being publicly disclosed for the first time. It is supported by a growing body of evidence and it contradicts the U.S. government's contention that the TMI accident posed no threat to the public. Thompson and his wife, a nuclear health physicist who also worked at TMI in the disaster's wake, warn that the government's failure to acknowledge the full scope of the disaster is leading officials to underestimate the risks posed by a new generation of nuclear power plants.

  19. United front may help prevent crisis.

    Science.gov (United States)

    2003-03-01

    Warnings of looming crisis are all around us, including within services for older people. Recent reports warn that the care home sector is reaching a critical juncture and, without long-term planning and investment, crisis will turn to meltdown ( Burstow 2003 ). In the past five years something like 50,000 long-term care beds have been lost and now, according to the National Audit Office, tens of thousands of older people each year find themselves unable to leave hospital because there is insufficient post-hospital care (see page five ). Emergency hospital readmissions have increased by nearly 20 per cent over the past two years and the reality of intermediate care has yet to live up to the policy rhetoric.

  20. Thermohydraulics in a high-temperature gas-cooled reactor primary loop during early phases of unrestricted core-heatup accidents

    International Nuclear Information System (INIS)

    Kroeger, P.G.; Colman, J.; Hsu, C.J.

    1983-01-01

    In High Temperature Gas Cooled Reactor (HTGR) siting considerations, the Unrestricted Core Heatup Accidents (UCHA) are considered as accidents of highest consequence, corresponding to core meltdown accidents in light water reactors. Initiation of such accidents can be, for instance, due to station blackout, resulting in scram and loss of all main loop forced circulation, with none of the core auxiliary cooling system loops being started. The result is a slow but continuing core heatup, extending over days. During the initial phases of such UCHA scenarios, the primary loop remains pressurized, with the system pressure slowly increasing until the relief valve setpoint is reached. The major objectives of the work described here were to determine times to depressurization as well as approximate loop component temperatures up to depressurization

  1. Analysis of articles in weekly magazines on scientific issues related to Fukushima nuclear power plant accident

    International Nuclear Information System (INIS)

    Sano, Kazumi; Kikuchi, Macoto

    2012-01-01

    The large area was polluted by the radioactive fallout released after the nuclear fuel meltdown of Fukushima first nuclear plant of Tokyo electric power company. The news media that reported the accident were required to have scientific knowledge on the structure of the nuclear reactor and the physics and health issues of the radioactivity. In this paper, we focus on how the weekly magazines reported this critical accident. The weekly magazines are not regarded as a neutral news media. Rather, their articles in general strongly reflect the editorial opinions. In this sense, the weekly magazines are 'biased media'. So, there are many points to discuss from the view point of the science communication. We analyze the articles appeared in the seven major weekly magazines published during the first half year after the earthquake. We found that the differences in the scientific literacy between magazines are reflected, for example, in selection of the experts who made comments in articles. (author)

  2. ILK statement on the consequences of the Chernobyl accident. Taking stock after twenty years

    International Nuclear Information System (INIS)

    2006-01-01

    The Chernobyl reactor accident was the consequence of a reactor design which was not inherently safe, and of a lack of 'safety culture'. The RBMK-type reactor (a Russian graphite-moderated light water reactor design: reaktor bolshoi moshnosty kanalny=high-power channel reactor) had not been designed to a satisfactory safety level, and the operating staff were not informed on the weak spots in plant design. The combination of these factors caused the worst nuclear accident, completely destroying the reactor. The consequences may be seen as the product of two severe accidents superimposed upon each other: the explosion of the reactor, and core melt-down associated with an intense, persistent fire of the graphite moderator. The Statement contains analyses of these points: Release, Propagation and Deposition of Radioactive Materials; Protective Measures; Impact on the Environment and Agriculture; Assessment of Radiation Exposure; Health Impact; Psychological and Societal Impacts; Potential Residual Risks. (orig.)

  3. Radiation thermometry for semiconductor crystal growing furnaces

    International Nuclear Information System (INIS)

    Helgeland, W.

    1985-01-01

    Single crystals of silicon produced by the Czochralski process are used widely in the production of integrated circuits and other electronic devices. Recent advances in automation of industrial equipment for this process have led to the application of a dual wave band radiation thermometer. The instrument system automatically performs certain critical temperature measurements. In nonautomated equipment, these measurements require the judgement of a trained human operator. The difficulties of measuring and controlling the temperature at the critical location are discussed, especially with regard to detecting the meltdown end point and to initially establishing the correct temperature for seeding. A description is given of the customized temperature measurement system, which is based upon an existing ratio radiation thermometer. Thermometer output characteristics are described

  4. Phenomenological modelling of steam explosions

    International Nuclear Information System (INIS)

    Corradini, M.L.; Drumheller, D.S.

    1980-01-01

    During a hypothetical core meltdown accident, an important safety issue to be addressed is the potential for steam explosions. This paper presents analysis and modelling of experimental results. There are four observations that can be drawn from the analysis: (1) vapor explosions are suppressed by noncondensible gases generated by fuel oxidation, by high ambient pressure, and by high water temperatures; (2) these effects appear to be trigger-related in that an explosion can again be induced in some cases by increasing the trigger magnitude; (3) direct fuel liquid-coolant liquid contact can explain small scale fuel fragmentation; (4) heat transfer during the expansion phase of the explosion can reduce the work potential

  5. Material review of Li ion battery separators

    Science.gov (United States)

    Weber, Christoph J.; Geiger, Sigrid; Falusi, Sandra; Roth, Michael

    2014-06-01

    Separators for Li Ion batteries have a strong impact on cell production, cell performance, life, as well as reliability and safety. The separator market volume is about 500 million m2 mainly based on consumer applications. It is expected to grow strongly over the next decade for mobile and stationary applications using large cells. At present, the market is essentially served by polyolefine membranes. Such membranes have some technological limitations, such as wettability, porosity, penetration resistance, shrinkage and meltdown. The development of a cell failure due to internal short circuit is potentially closely related to separator material properties. Consequently, advanced separators became an intense area of worldwide research and development activity in academia and industry. New separator technologies are being developed especially to address safety and reliability related property improvements.

  6. Material review of Li ion battery separators

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Christoph J., E-mail: Christoph.Weber@freudenberg-nw.com; Geiger, Sigrid, E-mail: Christoph.Weber@freudenberg-nw.com [Freudenberg Vliesstoffe SE and Co KG, 69465 Weinheim (Germany); Falusi, Sandra; Roth, Michael [Freudenberg Forschungsdienste SE and Co KG, 69465 Weinheim (Germany)

    2014-06-16

    Separators for Li Ion batteries have a strong impact on cell production, cell performance, life, as well as reliability and safety. The separator market volume is about 500 million m{sup 2} mainly based on consumer applications. It is expected to grow strongly over the next decade for mobile and stationary applications using large cells. At present, the market is essentially served by polyolefine membranes. Such membranes have some technological limitations, such as wettability, porosity, penetration resistance, shrinkage and meltdown. The development of a cell failure due to internal short circuit is potentially closely related to separator material properties. Consequently, advanced separators became an intense area of worldwide research and development activity in academia and industry. New separator technologies are being developed especially to address safety and reliability related property improvements.

  7. Institut fuer Radiochemie: Results of R and D work in 1984

    International Nuclear Information System (INIS)

    1985-02-01

    The Radiochemistry Institute of KfK participates in the following projects: Reprocessing and waste treatment, fast breeder reactor, nuclear safety, safeguards, nuclear fusion. Other activities include research work on solids and materials, and in the field of water technology. The work accomplished in 1984 is explained in several contributions, the main topics being: Release and behaviour of fission products in sodium-cooled systems, analytic methods and in-line instrumentation within the framework of waste reprocessing techniques, Kr-85 separation from radioactive waste, fission product separation and tritium enrichment for waste disposal, fission product release during core meltdown, lithium silicates as fertile material for fusion reactors, water desolination with the CARIX process and other water purification methods. (RB) [de

  8. Soil surface decontamination and revegetation progress

    International Nuclear Information System (INIS)

    Graves, A.W.

    1981-01-01

    A review is given of work by Rockwell Hanford Operations related to large-area decontamination efforts. Rockwell has a Program Office which manages the decontamination and decommissioning (D and D) efforts. Part of the program is involved with large-surface area cleanup in conjunction with surveillance and maintenance of retired sites and facilities. The other part is the decontamination and decommissioning of structures. There are 322 surplus contaminated sites and facilities for which Rockwell has responsibility on the Hanford Site. A Program Office was established for a disciplined approach to cleanup of these retired sites. There are three major projects: the first is surveillance and maintenance of the sites prior to D and D, the project under which the radiation area cleanup is contained. Another project is for contaminated-equipment volume reduction; size reduction with arc saw cut-up and volume reduction with a vacuum furnace meltdown are being used. The third major project is structural D and D

  9. Provisions for containment venting in Germany

    International Nuclear Information System (INIS)

    Wilhelm, J.G.

    1997-01-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab

  10. Theoretical and experimental methods to determine the properties of molten core components and reaction products. Pt. 2

    International Nuclear Information System (INIS)

    Nazare, S.; Ondracek, G.; Schulz, B.

    1975-10-01

    In the course of a loss of coolant accident, a sequence of events would be initiated that ultimately could lead to core melting. The course of these events and the consequences of core meltdown would in part be determined by the properties of the core materials and the products of their interaction. On the basis of available theoretical and experimental results, the report attempts an estimation of properties such as: 1) work of adhesion between UO 2 - and (U,Zr) liquid phase, 2) heat of fusion of some melts, 3) heat capacity of liquid reaction products, 4) viscosity of liquid reaction products, 5) thermal conductivity of liquid reaction products. Experimental work is suggested for those cases, where the estimates need to be improved or verified. (orig.) [de

  11. A risk-economic approach to nuclear power generation. Beyond the myth of absolute safety and unthinkable events

    International Nuclear Information System (INIS)

    Sakai, Yasuhiro

    2012-01-01

    This paper deals with a risk-economic approach to nuclear power generation, a very timely yet rather neglected area in the economics profession. The economic and psychological consequences of Japan's recent catastrophe have been so grave and wide-spread, thus calling for careful reexamination of the economics of risk and uncertainty. It is Daniel Bernoulli, a mathematical genius of the 18 th century, who first introduced the expected utility theory into decision making under risk. Although a great deal of applications has been done in many areas since then, it appears that the most recent nuclear meltdown of Japan is casting serious doubt upon the general validity of existing risk theories. It is high time for us to establish a new comprehensive approach by taking account of psychological, sociological, cultural, and historical factors. (author)

  12. Residual risk over-estimated

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    The way nuclear power plants are built practically excludes accidents with serious consequences. This is attended to by careful selection of material, control of fabrication and regular retesting as well as by several safety systems working independently. But the remaining risk, a 'hypothetic' uncontrollable incident with catastrophic effects is the main subject of the discussion on the peaceful utilization of nuclear power. The this year's 'Annual Meeting on Nuclear Engineering' in Mannheim and the meeting 'Reactor Safety Research' in Cologne showed, that risk studies so far were too pessimistic. 'Best estimate' calculations suggest that core melt-down accidents only occur if almost all safety systems fail, that accidents take place much more slowly, and that the release of radioactive fission products is by several magnitudes lower than it was assumed until now. (orig.) [de

  13. Probabilistic reliability analyses to detect weak points in secondary-side residual heat removal systems of KWU PWR plants

    International Nuclear Information System (INIS)

    Schilling, R.

    1984-01-01

    Requirements made by Federal German licensing authorities called for the analysis of the second-side residual heat removal systems of new PWR plants with regard to availability, possible weak points and the balanced nature of the overall system for different incident sequences. Following a description of the generic concept and the process and safety-related systems for steam generator feed and main steam discharge, the reliability of the latter is analyzed for the small break LOCA and emergency power mode incidents, weak points in the process systems are identified, remedial measures of a system-specific and test-strategic nature are presented and their contribution to improving system availability is quantified. A comparison with the results of the German Risk Study on Nuclear Power Plants (GRS) shows a distinct reduction in core meltdown frequency. (orig.)

  14. Reliability analyses to detect weak points in secondary-side residual heat removal systems of KWU PWR plants

    International Nuclear Information System (INIS)

    Schilling, R.

    1983-01-01

    Requirements made by Federal German licensing authorities called for the analysis of the secondary-side residual heat removal systems of new PWR plants with regard to availability, possible weak points and the balanced nature of the overall system for different incident sequences. Following a description of the generic concept and the process and safety-related systems for steam generator feed and main steam discharge, the reliability of the latter is analyzed for the small break LOCA and emergency power mode incidents, weak points in the process systems identified, remedial measures of a system-specific and test-strategic nature presented and their contribution to improving system availability quantified. A comparison with the results of the German Risk Study on Nuclear Power Plants (GRS) shows a distinct reduction in core meltdown frequency. (orig.)

  15. German Light-Water-Reactor Safety-Research Program

    International Nuclear Information System (INIS)

    Seipel, H.G.; Lummerzheim, D.; Rittig, D.

    1977-01-01

    The Light-Water-Reactor Safety-Research Program, which is part of the energy program of the Federal Republic of Germany, is presented in this article. The program, for which the Federal Minister of Research and Technology of the Federal Republic of Germany is responsible, is subdivided into the following four main problem areas, which in turn are subdivided into projects: (1) improvement of the operational safety and reliability of systems and components (projects: quality assurance, component safety); (2) analysis of the consequences of accidents (projects: emergency core cooling, containment, external impacts, pressure-vessel failure, core meltdown); (3) analysis of radiation exposure during operation, accident, and decommissioning (project: fission-product transport and radiation exposure); and (4) analysis of the risk created by the operation of nuclear power plants (project: risk and reliability). Various problems, which are included in the above-mentioned projects, are concurrently studied within the Heiss-Dampf Reaktor experiments

  16. Application of nanofluids to mitigation of severe accident at the Fukushima Daiichi Nuclear Power Plant

    International Nuclear Information System (INIS)

    Suh, Kune Y.

    2011-01-01

    This paper presents the pivotal thermohydrodynamic and neutronic characteristics of nanofluids as an alternative coolant for boiling water reactors (BWRs) during the abnormal operation including, but not necessarily limited to, severe accident involving meltdown as well as potentially melt-through of the reactor core material. Results indicate that the benefit of utilizing nanoparticles in the BWR working fluid appears to be minimal during the nominal operation since the nanoparticles tend to carry over to the turbine and condenser lending themselves to erosion and fouling concerns. Good news, on the other hand, is that exploitation of nanofluids during the decay heat removal condition in case of an accident is promising indeed because of their high thermal conductivity and their neutron poisoning effect. Thermohydrodynamic and neutronic investigations are in progress to streamline the nanoparticles and to optimize their concentration during the abnormal operation beyond the conventional design basis extending to severe accident. (author)

  17. Health physics aspects of processing EBR-I coolant

    International Nuclear Information System (INIS)

    Burke, L.L.; Thalgott, J.O.; Poston, J.W. Jr.

    1998-01-01

    The sodium-potassium reactor coolant removed from the Experimental Breeder Reactor Number One after a partial reactor core meltdown had been stored at the Idaho National Engineering and Environmental Laboratory for 40 years. The State of Idaho considered this waste the most hazardous waste stored in the state and required its processing. The reactor coolant was processed in three phases. The first phase converted the alkali metal into a liquid sodium-potassium hydroxide. The second phase converted this caustic to a liquid sodium-potassium carbonate. The third phase solidified the sodium-potassium carbonate into a form acceptable for land disposal. Health physics aspects and dose received during each phase of the processing are discussed

  18. The modular pebble bed nuclear reactor - the preferred new sustainable energy source for electricity, hydrogen and potable water production?

    International Nuclear Information System (INIS)

    Kemeny, L.G.

    2003-01-01

    This paper describes a joint project of Massachusetts Institute of technology, Nu-Tec Inc. and Proto Power. The elegant simplicity of graphite moderated pebble bed reactor is the basis for the 'generation four' nuclear power plants. High Temperature Gas Cooled (HTGC) nuclear power plant have the potential to become the preferred base load sustainable energy source for the new millennium. The great attraction of these helium cooled 'Generation Four' nuclear plant can be summarised as follows: Factory assembly line production; Modularity and ease of delivery to site; High temperature Brayton Cycle ideally suited for cogeneration of electricity, potable water and hydrogen; Capital and operating costs competitive with hydrocarbon plant; Design is inherently meltdown proof and proliferation resistant

  19. A Parameter Study of Large Fast Reactor Nuclear Explosion Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Wiesel, J R

    1969-02-15

    An IBM-code EEM (Explosive Excursion Model) has been developed for calculating the energy releases associated with the explosive disassembly of a large fast reactor following a superprompt critical condition. The assumed failure chain of events and the possible core collapse following a fuel meltdown give the input data and initial conditions, the most important of which is the reactivity insertion rate at the moment of the explosive core disassembly. The dependence of the energy releases on the reactivity insertion rate, the Doppler reactivity feedback, the power form factor and the core size have been studied. The model enables a quick estimation of conservative values of the destructive mechanical energy releases following a nuclear explosion and gives suggestions as to how to reduce or even avoid such excursions.

  20. From Hiroshima to Harrisburg. The unholy alliance

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, J

    1980-01-01

    The subject is covered in chapters, as follows: (Part I): Hiroshima and the advent of the atomic bomb: the Manhattan Engineer District Project; the milieu of war; scientific opposition to the use of the atomic bomb; Trinity; Hiroshima; Nagasaki and surrender; Hibakusha; from trust to terror; the nuclear arms spiral; fallout; the rationale for nuclear weapons; nuclear proliferation; thinking the unthinkable; the age of overkill; (Part II):the road to Harrisburg: radiation; meltdown effects and probabilities; nuclear accidents; Harrisburg; the effects of low-level ionizing radiation; the nuclear fuel cycle (mining; milling; uranium conversion; uranium enrichment; fuel fabrication; nuclear reactors; reprocessing; transportation; waste management; summary); (Part III): Karen Silkwood - a life in death: (Part IV): our challenge - overcoming psychic numbing: (Part V): an alternative vision: the soft energy path; the way of nonviolence.

  1. From Hiroshima to Harrisburg

    International Nuclear Information System (INIS)

    Garrison, J.

    1980-01-01

    The subject is covered in chapters, as follows: (Part I): Hiroshima and the advent of the atomic bomb: the Manhattan Engineer District Project; the milieu of war; scientific opposition to the use of the atomic bomb; Trinity; Hiroshima; Nagasaki and surrender; Hibakusha; from trust to terror; the nuclear arms spiral; fallout; the rationale for nuclear weapons; nuclear proliferation; thinking the unthinkable; the age of overkill; (Part II):the road to Harrisburg: radiation; meltdown effects and probabilities; nuclear accidents; Harrisburg; the effects of low-level ionizing radiation; the nuclear fuel cycle (mining; milling; uranium conversion; uranium enrichment; fuel fabrication; nuclear reactors; reprocessing; transportation; waste management; summary); (Part III): Karen Silkwood - a life in death: (Part IV): our challenge - overcoming psychic numbing: (Part V): an alternative vision: the soft energy path; the way of nonviolence. (U.K.)

  2. Observations on PRA and its applications

    International Nuclear Information System (INIS)

    Yeh, Y.-C.; Shieh, S.-L.

    2004-01-01

    An overview on the experience of PRA and its prospective application in Taiwan's three nuclear power plants is presented. Through the PRA, plant design improvements are performed and several engineering findings are illuminated. The sensitivity study including the internal, seismic, and typhoon events are conducted to justify items that can significantly reduce core meltdown risk. Its resulted plant betterment plans are thus highlighted accordingly. For PRA application, a risk-based inspection program for allocating inspection human resources has been resulted following the importance ranking of each component. The developing risk-based regulation to rationalize technical specification and maintenance program will also be entailed. To enhance the accuracy of the PRA model and its reproducibility, several issues are considered to have high priority for improvement such as external event data and analyses, uncertainty, common mode failure, human reliability, and the relative component importance. Highlight of their significance along with some typical sensitivity analyses are discussed for further investigation. (author)

  3. Design modification of the El Cabril disposal facility for the treatment of steelyard ASH

    International Nuclear Information System (INIS)

    Navarro Santos, M.; Ugarte Pallares, A.

    2000-01-01

    This paper described in general terms the management performed at the El Cabril Disposal Facility for the radioactive wastes generated as a result of the incident involving the meltdown of a Cs-137 source at a steelyard in Los Barrios (Cadiz), in the Bay of Algeciras. The greater part of this waste stream, consisting of dust from fumes, dry sludges, inert wastes, slag, earths and refractory materials, will be conditioned by mixing them with the waste package blocking mortar in the containers. This conditioning will allow the wastes to be immobilized in a solid matrix, without them occupying any additional volume at the facility and without altering the configuration of the disposal unit of the El Cabril Disposal Facility. The rest of the wastes generated: plastics, rubber, cloths and dust filters, will be conditioned by pressing, this producing compacted slabs which will be immobilized in containers or incinerated, as the case may be. (Author)

  4. Severe accident analysis using MARCH 1.0 code

    International Nuclear Information System (INIS)

    Guimaraes, A.C.F.

    1987-09-01

    The description and utilization of the MARCH 1.0 computer code, which aim to analyse physical phenomena associated with core meltdown accidents in PWR type reactors, are presented. The primary system is modeled as a single volume which is partitioned into a gas (steam and hydrogen) region and a water region. March predicts blowdown from the primary system in single phase. Based on results of the probabilistic safety analysis for the Zion and Indian Point Nuclear Power Plants, the S 2 HFX sequence accident for Angra-1 reactor is studied. The S 2 HFX sequence means that the loss of coolant accident occurs through small break in primary system with bot total failures of the reactor safety system and containment in yours recirculation modes, leading the core melt and the containment failure due to overpressurization. The obtained results were considered reasonable if compared with the results obtained for the Zion and Indian Point nuclear power plants. (Author) [pt

  5. Concluding colloquium of the Nuclear Safety Project (PNS)

    International Nuclear Information System (INIS)

    1986-08-01

    The main points of the report are: environmental loads due to nuclear power stations and fuel reprocessing plants, behaviour of the system during reactor faults, extent of damage for the largest hypothetical reactor accidents and its dependence on time, assessment of the consequences of large hypothetical accidents and safety-related assessment of nuclear plants. The contributions relate particularly to the dynamic stresses on reactor components, behaviour of fuel elements in accidents, core melt-down accidents in LWR's and retention, behaviour and effects of released radionuclides from nuclear plants. Up-dating contributions concern the course, the effects and the analysis of the Chernobyl reactor accident. One contribution each is concerned with the development of waste air filters, the soil/plant transfer of actinides and the description of an FDWR. (DG) [de

  6. Measures for removing hydrogen

    International Nuclear Information System (INIS)

    Baukal, W.; Koehling, A.; Langer, G.; Poeschel, E.

    1984-01-01

    Basis for the investigation is a 1300-MW-PWR. The evolution of hydrogen was studied in design-basis and three hypothetical accident scenarios, the loss-of-coolant accident, the failure of emergency cooling system and core meltdown. It was shown that in the case of release rates of 4m 3 H 2 /h, the known post-accident hydrogen removal systems can be used and at medium rates up to 80 m 3 H 2 /h recombines of nuclear and non-nuclear industries are suitable under certain conditions. In the case of larger release rates it appears useful to apply a small recombiner of the type of the post-accident hydrogen removal system combined with an other hydrogen countermeasures. Recommendations are being made for the installation of an accident-proof hydrogen measuring system. (DG) [de

  7. Safety evaluation report in the matter of Offshore Power Systems Floating Nuclear Plants (1-8). Docket No. STN 50-437

    International Nuclear Information System (INIS)

    1980-02-01

    The staff has performed an evaluation of a refractory sacrificial bed, called a core ladle, proposed by Offshore Power Systems (OPS) to be installed in Floating Nuclear Plants (FNPs) to delay the melt-through penetration of molten core debris in the unlikely event of a core meltdown accident. The core ladle design as proposed by OPS is in response to the staff's manufacturing license Condition 4 given in the Final Environmental Statement, Part III, NUREG-0502, dated December 1978 (FES-III). This condition requires that a pad constructed of magnesium oxide, or other equivalent refractory material, be installed in the FNP structure within the lower reactor cavity. The material must provide increased resistance to melt-through by the molten reactor core, must not react with core debris to form a large volume of gases, and must not have any deleterious effects on safety

  8. Method for consequence calculations for severe accidents

    International Nuclear Information System (INIS)

    Nielsen, F.; Thykier-Nielsn, S.

    1987-03-01

    This report was commissioned by the Swedish State Power Board. The report contains a calculation of radiation doses in the surroundings caused by a theoretical core meltdown accident at Forsmark reactor No 3. The assumption used for the calculations were a 0.06% release of iodine and cesium corresponding to a 0.1% release through the FILTRA plant at Barsebaeck. The calculations were made by means of the PLUCON4 code. Meteorological data for two years from the Forsmark meteorological tower were analysed to find representative weather situations. As typical weather pasquill D was chosen with wind speed 5 m/s, and as extreme weather, Pasquill F with wind speed 2 m/s. 23 tabs., 36 ills., 21 refs. (author)

  9. Method for consequence calculations for servere accidents

    International Nuclear Information System (INIS)

    Nielsen, F.

    1987-01-01

    With the exception of the part about collective doses, this report was commissioned by the Swedish State Power Board. The part about collective doses was commissioned by the Swedish National Institute of Radiation Protection. The report contains a calculation of radiation doses in the sursurroundings caused by a theoretical core meltdown accident at one of the Barsebaeck reactors with filtered venting through the FILTRA plant. The calculations were made by means of the PLUCON4 code. The assumption used for the calculations were givon by the Swedish National Institute of Radiation Protection as follows: Pasquill D with wind speed 3 m/s and a mixing layer at 300 m height. Elevation of the release: 100 m with no energy release. The release starts 12 hours after shut-down and its duration is one hour. The release contains 100% of the noble gasses and 0,1% of all other isotopes in a 1800 MW t -reactor. (author)

  10. Method for consequence calculations for severe accidents

    International Nuclear Information System (INIS)

    Nielsen, F.

    1988-07-01

    This report was commissioned by the Swedish State Power Board. The report contains a calculation of radiation doses in the surroundings caused by a theoretical core meltdown accident at Forsmark reactor No 3. The accident sequence chosen for the calculating was a release caused by total power failure. The calculations were made by means of the PLUCON4 code. Meteorological data for two years from the Forsmark meteorological tower were analysed to find representative weather situations. As typical weather, Pasquill D was chosen with a wind speed of 5 m/s, and as extreme weather, Pasquill F with a wind speed of 2 m/s. 23 tabs., 37 ills., 20 refs. (author)

  11. Method for consequence calculations for severe accidents

    International Nuclear Information System (INIS)

    Nielsen, F.; Thykier-Nielsen, S.; Walmod-Larsen, O.

    1986-08-01

    This report was commissioned by the Swedish State Power Board, who wanted a method for calculation of radiation doses in the surroundings of nuclear power plants caused by severe accidents. The PLUCON4 code were used for the calculations. A TC-SV-accident at Ringhals 1 wer chosen as example. A transient without shutdown leads to core meltdown through the reactor vessel. The pressure peak at the moment of vessel failure opens a safety valve in the dry well. Meteorolgical data for two years from the Ringhals meteorological tower were analysed to find representative weather situations. As typical weather were chosen Pasquill D with wind speed 8 m/s, and as extreme weather were chosen Pasquill F with wind speed 4.8 m/s. (author)

  12. Method for consequence calculations for severe accidents

    International Nuclear Information System (INIS)

    Nielsen, F.

    1988-01-01

    This report was commissioned by the Swedish State Power Board. The report contains a calculation of radiation doses in the surroundings caused by a theoretical core meltdown accident at Ringhals reactor No 3/4. The accident sequence chosen for the calcualtions was a release caused by total power failure. The calculations were made by means of the PLUCON4 code. A decontamination factor of 500 is used to account for the scrubber effect. Meteorological data for two years from the Ringhals meteorological tower were analysed to find representative weather situations. As typical weather, Pasquill D, was chosen with a wind speed of 10 m/s, and as extreme weather, Pasquill E, with a wind speed of 2 m/s. 19 refs. (author)

  13. A condensed review of the core catcher in the LMR

    International Nuclear Information System (INIS)

    Lee, Yong Bum; Hahn, Do hee

    2001-03-01

    The overwhelming emphasis in reactor safety is on the prevention of core meltdown. Moreover, although there have been several accidents that have resulted in some fuel melting, to date there have been no accidents severe enough to cause the syndrome of core collapse, reactor vessel melt-through, containment penetration, and dispersal into the ground. Nevertheless, a number of proposals have been made for the design of core catcher systems to control or stop the motion of the molten core mass should such an accident take place. Core catchers may differ in both their location within the reactor system and in the mechanism that is used to cool and control the motion of the core debris. In this report the classification, configuration and main features of the core catcher are described. And also, the core catcher provisions in constructed and planned LMRs (Liquid Metal Reactors) are summarized

  14. "Wandering in the Desert": The Clinch River Breeder Reactor Debate in the U.S. Congress, 1972-1983.

    Science.gov (United States)

    Camp, Michael

    2018-01-01

    The experimental Clinch River breeder reactor, approved by the U.S. Congress in 1970 for construction in East Tennessee, would have used plutonium instead of uranium. The project drew the ire of environmentalists who insisted that plutonium was too dangerous for commercial use, along with opponents of nuclear proliferation. Tennessee's representatives in Congress, however, desired the jobs that the project would create, and formed legislative coalitions to ensure continued appropriations for the project. Funding lasted until 1983, when fiscal conservatives, concerned about ballooning cost projections, joined with environmentalists to defund the breeder. Interpretations of U.S. nuclear policy in the 1980s have often revolved around the Three Mile Island meltdown's aftermath, but Clinch River was not affected by the incident. Instead, the Clinch River controversy revolved around other unrelated issues. The Clinch River story therefore offers a corrective to accounts that privilege national public opinion at the expense of other variables.

  15. A assessment of loss-of-heat-sink accident with scram in the LMFBR

    International Nuclear Information System (INIS)

    Bari, R.A.; Ludewig, H.; Pratt, W.T.; Sun, Y.H.

    1978-01-01

    A description of a slow core meltdown in a liquid metal fast breeder reactor is presented for conditions of loss-of-heat-sink following neutronic shutdown. Simple models are developed for the prediction of phase changes and/or relocation of the core materials including fuel, clad, ducts, control rod absorber material (B 4 C), and plenum gases. The sequence of events is accounted for and the accident progression is described up to the point of recriticality. The neutronic behavior of the disrupted core is analyzed in R-Z geometry with a static transport theory code. For most scenarios assessed, the reactor is expected to become recritical although large ramp rates are not anticipated. (author)

  16. Assessment of the loss-of-heat-sink accident with scram in the LMFBR

    International Nuclear Information System (INIS)

    Bari, R.A.; Ludewig, H.; Pratt, W.T.; Sun, Y.H.

    1978-01-01

    A description of a slow core meltdown in a liquid metal fast breeder reactor is presented for the conditions of loss-of-heat-sink following neutronic shutdown. Simple models are developed for the prediction of phase changes and/or relocation of the core materials including fuel, clad, ducts, control rod absorber material (B 4 C), and plenum gases. The sequence of events is accounted for and the accident progression is described up to the point of recriticality. The neutronic behavior of the disrupted core is analyzed in R-Z geometry with a static transport theory code. For most scenarios assessed, the reactor is expected to become recritical although large ramp rates are not anticipated

  17. Heat dissipating nuclear reactor

    Science.gov (United States)

    Hunsbedt, A.; Lazarus, J.D.

    1985-11-21

    Disclosed is a nuclear reactor containment adapted to retain and cool core debris in the unlikely event of a core meltdown and subsequent breach in the reactor vessel. The reactor vessel is seated in a cavity which has a thick metal sidewall that is integral with a thick metal basemat at the bottom of the cavity. The basemat extends beyond the perimeter of the cavity sidewall. Underneath the basemat is a porous bed with water pipes and steam pipes running into it. Water is introduced into the bed and converted into steam which is vented to the atmosphere. A plurality of metal pilings in the form of H-beams extend from the metal base plate downwardly and outwardly into the earth.

  18. Fukushima nuclear accident and the social responsibility of science

    International Nuclear Information System (INIS)

    Yoshioka, Hitoshi

    2011-01-01

    Five months had passed since Fukushima Daiichi Nuclear Power Plant (NPP) accident occurred but still there was no knowing when the accident ended. Released radioactivity seemed to be greater than one million terra Bq and if there occurred an explosive rupture of containment vessel due to the failure of containment vent or occurrence of steam explosion, the amount of released radioactivity might amount to be at least equivalent to or surpass that of Chernobyl NPP accident. There existed still a risk that overheating and meltdown of nuclear fuels might reoccur with loss of cooling due to a possible giant aftershock. This article described total views on significant disaster that the accident brought about on many neighboring residents or wide range of people. After a general discussion about what was social responsibility of scientists, social responsibility of scientists for Fukushima Daiichi NPP accident was discussed. Responsibility of omission was also argued. (T. Tanaka)

  19. Improvement of the safety level of installations with the generalization of procedures

    International Nuclear Information System (INIS)

    Cornille, Y.; Dupraz, B.; Schektman, N.

    1986-06-01

    The generalization of control procedures to the largest possible spectra of accidental situations which is being developed on pressurized water reactor units will allow to increase the safety level of these installations. This improvement has been quantified for some situations pointing out an appreciable mitigation of meltdown risk which could result. A new improvement is aimed with the definition and the utilization of new procedures ''by states'' which will allow an optimized treatment of situations resulting from multiple failures, now treated in the procedures SPI - SPU - U1. The needs related to these procedures and their development led to joint research and development programs between Electricite de France and the Institute of Protection and Nuclear Safety [fr

  20. RASPLAV package

    International Nuclear Information System (INIS)

    1990-01-01

    The RASPLAV package for investigation of post-accident mass transport and heat transfer processes is presented. The package performs three dimensional thermal conduction calculations in space nonuniform and temperature dependent conductivities and variable heat sources, taking into account phase transformations. The processes of free-moving bulk material, mixing of melting fuel due to advection and dissolution, and also evaporation/adsorption are modelled. Two-dimensional hydrodynamics with self-consistent heat transfer are also performed. The paper briefly traces the ways the solution procedures are carried out in the program package and outlines the major results of the simulation of reactor vessel melting after a core meltdown. The theoretical analysis and the calculations in this case were carried out in order to define the possibility of localization of the zone reminders. The interactions between the reminders and the concrete are simulated and evaluation of the interaction parameters is carried out. 4 refs. (R.Ts)

  1. Fukushima. Five years on - FAQs

    International Nuclear Information System (INIS)

    2016-03-01

    On 11 March 2011, at 2:46 p.m. local time (6.46 a.m. CET), an earthquake measuring 9 on the Richter scale hit the east coast of Japan. The quake caused a tsunami, with waves as high as 38 metres, which led to large-scale flooding and destruction of roads, the power supply and other infrastructure along Japan's eastern seaboard. The earthquake and tsunami also struck several nuclear power plants. Fukushima Daiichi sustained the worst damage, triggering a chain of events which led to core meltdown, major hydrogen explosions and massive releases of radiation. Below, the Oeko-Institut answers the key questions about the disaster's timeline, latest assessments of the events, and the current situation in Fukushima.

  2. Safety-oriented LWR research. Annual report 1987

    International Nuclear Information System (INIS)

    1988-06-01

    The annual report 1987 includes the results of out-of-pile bundle experiments for severe fuel damage investigations (CORA), aerosol behaviour under core meltdown accident condition, dynamic behaviour of PWR containments, theoretical and experimental investigations of crack growth under thermal and thermomechanical fatigue loading, the thermal hydraulic code COMMIX-1B, the interfacial exchange processes in two-phase flow (NOVA-Program), the retention of penetrating iodine species, the development of exhaust filters and HEPA filter systems, advanced PWR's (APWR's) and related safety considerations, the HERA test facility and the KRISTA-program, and RELAP5/MOD2 post-test analysis of a forced feed reflood experiment. 20 papers are separately indexed in the database. (DG)

  3. Investigation of the failure of a reactor pressure vessel by plastic instability

    International Nuclear Information System (INIS)

    Laemmer, H.; Ritter, B.

    1994-01-01

    A possible consequence of a core meltdown accident in a pressurized water reactor is the failure of the reactor pressure vessel under high internal pressure. With the aid of the finite element program ABAQUS and using a material model of the thermo-plasticity for large deformation, the failure of the reactor pressure vessel due to plastic instability was examined. It was apparent from the finite element calculations that solely due to reduction in strength of the material, even for internal wall temperatures clearly below the core melt; of about 2000 C, the critical internal pressure can fall to values which are lower than the working pressure. With the aid of simplified geometry, a lower limit for the pressure at failure of the reactor pressure vessel can be calculated. (orig./HP) [de

  4. Pressure tube type reactors

    International Nuclear Information System (INIS)

    Komada, Masaoki.

    1981-01-01

    Purpose: To increase the safety of pressure tube type reactors by providing an additional ECCS system to an ordinary ECCS system and injecting heavy water in the reactor core tank into pressure tubes upon fractures of the tubes. Constitution: Upon fractures of pressure tubes, reduction of the pressure in the fractured tubes to the atmospheric pressure in confirmed and the electromagnetic valve is operated to completely isolate the pressure tubes from the fractured portion. Then, the heavy water in the reactor core tank flows into and spontaneously recycles through the pressure tubes to cool the fuels in the tube to prevent their meltdown. By additionally providing the separate ECCS system to the ordinary ECCS system, fuels can be cooled upon loss of coolant accidents to improve the safety of the reactors. (Moriyama, K.)

  5. Experimental studies on helium release and stratification within the AIHMS facility

    International Nuclear Information System (INIS)

    Prabhakar, Aneesh; Agrawal, Nilesh; Raghavan, V.; Das, Sarit K.

    2015-01-01

    Hydrogen is generated during core meltdown accidents in nuclear power plants. The study of hydrogen release and mixing within the containment is an important area of safety research. An experimental setup called the AERB-IIT Madras Hydrogen Mixing Studies (AIHMS) facility is setup at IIT Madras to study the distribution of helium (an inert surrogate to hydrogen) subsequent to release as a jet. The present paper gives details of the design, fabrication and instrumentation of the AIHMS facility. It then compares the features of the facility with respect to other facilities existing for hydrogen mitigation studies. Then it gives details of the experiments on concentration build-up studies as a result of injection of gases (air and helium) performed in this experimental facility. (author)

  6. Toxicology of plutonium-sodium

    International Nuclear Information System (INIS)

    Hackett, P.L.

    1982-01-01

    Scenarios for liquid-metal fast breeder reactor (LMFBR) accidents predict the loss of sodium coolant, with subsequent core melt-down and release of mixed sodium-fuel aerosols [Na-(PuU)O 2 ] into the environment. Studies in other laboratories demonstrated that mixed aerosols of Na 2 O-PuO 2 were more readily transported from the lung than PuO 2 aerosols. We therefore devised a continuous aerosol-generating system for animal exposures in which laser-generated fuel aerosols were swept through sodium vapor to form sodium-fuel aerosols. These fuel and sodium-fuel aerosols were compared with regard to their physicochemical properties and their biological behavior following inhalation studies in rats and dogs

  7. A Parameter Study of Large Fast Reactor Nuclear Explosion Accidents

    International Nuclear Information System (INIS)

    Wiesel, J.R.

    1969-02-01

    An IBM-code EEM (Explosive Excursion Model) has been developed for calculating the energy releases associated with the explosive disassembly of a large fast reactor following a superprompt critical condition. The assumed failure chain of events and the possible core collapse following a fuel meltdown give the input data and initial conditions, the most important of which is the reactivity insertion rate at the moment of the explosive core disassembly. The dependence of the energy releases on the reactivity insertion rate, the Doppler reactivity feedback, the power form factor and the core size have been studied. The model enables a quick estimation of conservative values of the destructive mechanical energy releases following a nuclear explosion and gives suggestions as to how to reduce or even avoid such excursions

  8. the accident at Three Mile Island

    International Nuclear Information System (INIS)

    Torrey, L.

    1979-01-01

    The recently published final report of the President's Commision on the accident at Three Mile Island (TMI) is considered. In the report the power utilities and the US Nuclear Regulatory Commission (NRC) are severely criticised for being 'unable to provide an acceptable level of safety in nuclear power' which is reflected in the operators lack of training and understanding in depth. The 44 recommendations of the Commission include the abolition of the NRC, periodic renewal of operating licences, the siting of all future nuclear power plants away from large population centres, emergency response procedures to be improved and the revamping of warning display panels in control rooms. The commission also evaluated the severity of the accident and endeavoured to determine how close TMI came to a total catastrophic meltdown. The role of the media in the accident was also considered. (UK)

  9. Discussion of the H2 problem connected with possible measures to be taken to reduce the consequences of accidents

    International Nuclear Information System (INIS)

    Jahn, H.

    1983-01-01

    The German Reactor Safety Commission's guidelines provide for the design of emergency cooling systems that no more than 1% of the zirconium materials are to react with water in a loss-of-coolant incident. If this emergency cooling marginal value is also applied as the maximum value for hydrogen control, such design-related incidents will be technically controllable concerning hydrogen (flow mixing and recombination). This report dealt exclusively with questions arising from temporary excess core temperatures owing to emergency cooling that does not meet the requirements of design and causing substantial zirconium reactions with temporary excess hydrogen generation. In order to distinguish this type of incident from unproblematic design-related incidents for one thing and from cases with complete core meltdown for another thing, the term ''accident'' is applied. (orig./RW) [de

  10. Research and experience report 2008. Developments in the technical and legal basis of nuclear oversight

    International Nuclear Information System (INIS)

    2009-04-01

    This annual report issued by the Swiss Federal Nuclear Inspectorate (ENSI) reviews research into regulatory safety and the work done during 2008. In the area of reactor safety, research - in addition to research into materials - was concentrated primarily on safety and reliability analyses. ENSI supports projects looking at ageing mechanisms such as fatigue, corrosion, embrittlement and the development of cracks under a range of environmental conditions. Topics such as the interaction between core meltdown and water and concrete as well as the development of methods and computer codes are covered. In the area of transport and waste management, ENSI is focussing its efforts on research into the geological strata suitable for the final storage of highly radioactive, long-lived waste. Human and organisational factors and safety culture now account for an increasing part of the work of this regulatory body. Appendices present an overview of work done, international activities, publications and the basic principles of the new ENSI guidelines

  11. A synopsis of experimental activities on small-break LOCA

    International Nuclear Information System (INIS)

    Hein, D.

    1984-01-01

    Through reactor safety studies like WASH 1400 or the ''Deutsche Risiko-Studie'' the attention has turned from large break loss of coolant accidents to small breaks because of the high contribution of this type of accidents to core meltdown. But only after the TMI-2 accident were also the main activities in the experimental fields shifted world-wide to the small break LOCAs. Since TMI numerous research programs have either been finished or are underway. This review paper presents: a classification of the various types of transients according to break size; a discussion of major physical phenomena associated with a small break LOCA, and a description of a few selected research programs and the most important results achieved. (author)

  12. German risk study 'nuclear power plants, phase B'

    International Nuclear Information System (INIS)

    Heuser, F.W.

    1989-01-01

    The results of the German risk study 'Nuclear power plants, phase B' indicate that an accident in a nuclear power plant which cannot be managed by the safety systems according to design, is extremely improbable: Its probability is at about 3 to 100,000 per year and plant. Even if the safety systems fail, emergency measures can be effected in a nuclear power plant to prevent an accident. These in-plant emergency measures diminish the probability of a core meltdown to about 4 to 1,000,000 per year and plant. Hence, the accident risk is greatly reduced. The information given by the author are to smooth the emotional edge in the discussion about the safety of nuclear power plants. (orig.) [de

  13. Analysis of NSPP experiment with ART code for analyzing transport behavior of Aerosol and radionuclides

    International Nuclear Information System (INIS)

    Ishigami, Tsutomu; Kobayashi, Kensuke; Kajimoto, Mitsuhiro.

    1989-01-01

    The ART code calculates transport behavior of aerosols and radionuclides during core meltdown accidents in the light water reactors. Since aerosols play an important role in carrying fission products from the core region to the environment, the ART code includes detailed models of aerosol behavior. Aerosols including several radionuclides are classified into many groups according to the aerosol mass. The models of aerosol behavior include agglomeration processes caused by Brownian motion, aerosol settling velocity difference and turbulent flow, and natural deposition processes due to diffusion, thermophoresis, diffusiophoresis, gravitational settling and forced convection. In order to examine validity of the ART models, the NSPP aerosol experiment was analyzed. The ART calculated results showed good agreement with the experimental data. It was ascertained that aerosol growth due to agglomeration, gravitational settling, thermophoresis in an air atmosphere, and diffusiophoresis in an air-steam atmosphere were important physical phenomena in the aerosol behavior. (author)

  14. Serious accidents of PWR type reactors for power generation

    International Nuclear Information System (INIS)

    2008-12-01

    This document presents the great lines of current knowledge on serious accidents relative to PWR type reactors. First, is exposed the physics of PWR type reactor core meltdown and the possible failure modes of the containment building in such a case. Then, are presented the dispositions implemented with regards to such accidents in France, particularly the pragmatic approach that prevails for the already built reactors. Then, the document tackles the case of the European pressurized reactor (E.P.R.), for which the dimensioning takes into account explicitly serious accidents: it is a question of objectives conception and their respect must be the object of a strict demonstration, by taking into account uncertainties. (N.C.)

  15. Transients in a reactor containment after a HCDA

    International Nuclear Information System (INIS)

    Ghosh, A.K.

    1984-01-01

    The consequences of a hypothetical core meltdown accident in a fast reactor is analysed. Shock waves are generated in the surrounding medium after the energy release, which is assumed to be instantaneous and at a point. After discussing the difference in the predicted and experimentally observed peak pressure a semi-empirical approach is taken to arrive at a better estimate. This defines the loading on the containment, which is idealised as a combination of a shell and a plate. To simplify the analysis the shell is assumed to be in plane strain and axial symmetry is assumed for both components. The shell response is evaluated by using elasticity theory. Numerical results are presented for peak overpressure and pressure-time history and dynamic stresses in the containment. (Author) [pt

  16. Safety device for nuclear fission reactors

    International Nuclear Information System (INIS)

    Brownlee, M.L.

    1982-01-01

    A plurality of radially arranged and neutron absorbing baffles are stacked in vertical sets under the fuel core assemblies, and the whole enclosed in a bottle shaped containment vessel. The radially arranged baffles of each set extend vertically, and each set has double the number of baffles as the set above it in the stack. A melt-down of a fuel core assembly drops the fissioning nuclear fuel into the stacked sets of baffles, there, as it passes through, to be progressively divided, redivided and dispersed in smaller and smaller masses between the doubling number of baffles in safe fuel pellet size. Neutron absorbing containment prevents contamination of the environment and together with cooling means stops fissioning of fuel

  17. Measuring Public Acceptance of Nuclear Technology with Big data

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Seugkook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Surveys can be conducted only on people in specific region and time interval, and it may be misleading to generalize the results to represent the attitude of the public. For example, opinions of a person living in metropolitan area, far from the dangers of nuclear reactors and enjoying cheap electricity produced by the reactors, and a person living in proximity of nuclear power plants, subject to tremendous damage should nuclear meltdown occur, certainly differs for the topic of nuclear generation. To conclude, big data is a useful tool to measure the public acceptance of nuclear technology efficiently (i.e., saves cost, time, and effort of measurement and analysis) and this research was able to provide a case for using big data to analyze public acceptance of nuclear technology. Finally, the analysis identified opinion leaders, which allows target-marketing when policy is executed.

  18. Lessons of nuclear robot history

    International Nuclear Information System (INIS)

    Oomichi, Takeo

    2014-01-01

    Severe accidents occurred at Fukushima Daiichi Nuclear Power Station stirred up people's great expectation of nuclear robot's deployment. However unexpected nuclear disaster, especially rupture of reactor building caused by core meltdown and hydrogen explosion, made it quite difficult to introduce nuclear robot under high radiation environment to cease accidents and dispose damaged reactor. Robotics Society of Japan (RSJ) set up committee to look back upon lessons learned from 50 year's past experience of nuclear robot development and summarized 'Lessons of nuclear robot history', which was shown on the home page website of RSJ. This article outlined it with personal comment. History of nuclear robot developed for inspection and maintenance at normal operation and for specific required response at nuclear accidents was reviewed with many examples at home and abroad for TMI, Chernobyl and JCO accidents. Present state of Fukushima accident response robot's introduction and development was also described with some comments on nuclear robot development from academia based on lessons. (T. Tanaka)

  19. Present Trends In The Configurations And Applications Of Electrostatic Accelerator Systems

    International Nuclear Information System (INIS)

    Norton, Gregory A.; Klody, George M.

    2011-01-01

    Despite the worldwide economic meltdown during the past two years and preceding any stimulus program projects, the market for electrostatic accelerators has increased on three fronts: new applications developed in an expanding range of fields; technical enhancements that increase the range, precision, and sensitivity of existing systems; and new accelerator projects in a growing number of developing countries. From the single application of basic nuclear structure research from the 1930's into the 1970's, the continued expansion of new applications and the technical improvements in electrostatic accelerators have dramatically affected the configurations and capabilities of accelerator systems to meet new requirements. This paper describes examples of recent developments in cosmology, exotic materials, high resolution RBS, compact AMS, dust acceleration, ion implantation, etc.

  20. Review of the TMI-2 accident evaluation and vessel investigation projects

    Energy Technology Data Exchange (ETDEWEB)

    Ladekarl Thomsen, Knud

    1998-03-01

    The results of the TMI-2 Accident Evaluation Programme and the Vessel Investigation Project have been reviewed as part of a literature study on core meltdown and in-vessel coolability. The emphasis is placed on the late phase melt progression, which is of special relevance to the NKS-sponsored RAK-2.1 project on Severe Accident Phenomenology. The body of the report comprises three main sections, The TMI-2 Accident Scenario, Core Region and Relocation Path Investigations, and Lower Head Investigations. In the final discussion, the lower head gap formation mechanism is explained in terms of thermal contraction and fracturing of the debris crust. This model seems more plausible than the MAAP model based on creep expansion of the lower head. (au) 1 tab., 33 ills., 31 refs.

  1. The why of things: causality in science, medicine, and life

    CERN Document Server

    Rabins, Peter V.

    2013-01-01

    Why was there a meltdown at the Fukushima power plant? Why do some people get cancer and not others? Why is global warming happening? Why does one person get depressed in the face of life's vicissitudes while another finds resilience? Questions like these -- questions of causality -- form the basis of modern scientific inquiry, posing profound intellectual and methodological challenges for researchers in the physical, natural, biomedical, and social sciences. In this groundbreaking book, noted psychiatrist and author Peter Rabins offers a conceptual framework for analyzing daunting questions of causality. Navigating a lively intellectual voyage between the shoals of strict reductionism and relativism, Rabins maps a three-facet model of causality and applies it to a variety of questions in science, medicine, economics, and more. Throughout this book, Rabins situates his argument within relevant scientific contexts, such as quantum mechanics, cybernetics, chaos theory, and epigenetics. A renowned communicator o...

  2. Some consideration on reviewing of WWER

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Heki [Yokohama National University, Mechanical Engineering and Material Sciences, Tokiwadai, Hodogaya, Yokohama (Japan)

    1993-07-01

    The main points of NPP safety are to prevent core melt-down and to mitigate the divergence of radioactive materials to the atmosphere in general. However, destroying of the reactor building may cause damages of various mechanical and other components and piping systems, and these failures may proceed to LOCA and other critical failures of safety related items. The main items that are considered in view of upgrading the existing WWER type reactors are: buildings, emergency power supply systems, anchoring devices and concrete structures, mechanical components, water storage, piping support, civil engineering structure. This pipe describes the method for improving seismic capacity of the operating NPPs and to keep their safety under seismic conditions.

  3. Risk of the research reactor BER II in Berlin

    International Nuclear Information System (INIS)

    Paulitz, Henrik; Hoevener, Barbara; Rosen, Alex

    2015-01-01

    The research reactor BER II is sited at the periphery of Berlin in the neighborhood of residential areas. The operational license is limited until December 31, 2019. The reactor is funded by the Federal Government (90%) and the city of Berlin (10%). The stress test has shown that the reactor is not secured against an aircraft crash (airliner or fast flying military jet), meltdown with remarkable radiological consequences to the public would be the consequence. Further hazards result from the radioactive waste transport, explosions and fires. The emergency measures cannot be considered to be sufficient. The city of Berlin would not be able to fulfill the required measures in case of a radiation accident.

  4. Cost-benefit analyses for decommissioning and dismantling of nuclear power stations

    International Nuclear Information System (INIS)

    Hock, R.

    1988-01-01

    According to ICRP provisions, radiation doses to the population are to be kept as low as possible, on the basis of a justifiable relationship between additional expense for dose reduction and the radiological benefit. The paper examines whether this optimisation principle requires maximum conceivable limits of personal doses as a result of materials recovery from dismantling ought to be reviewed, and whether clearance levels for materials to be recycled have to be reduced. The cost-benefit assessments presented for various options take into account the cost involved for processing and recycling methods as well as the social burden of dose commitments. A comparison in terms of radiological safety is presented for ultimate disposal of material, or meltdown of material subject to appropriate radiological measurement and surveillance. (DG) [de

  5. NAUA-Mod 3 - A computer code for the description of the aerosol behaviour in a condensing atmosphere

    International Nuclear Information System (INIS)

    Bunz, H.; Koyro, M.; Schoeck, W.

    1981-09-01

    This report gives a description of the computer code NAUA-Mod 3. Its purpose is to calculate the behaviour of a polydisperse aerosol system in the containment of a light water reactor after a postulated core meltdown accident as a function of the time. The most important effect being added to those already taken into account in comparable computer codes is the steam condensation onto the particles. In the report the equations taken as basis of the code are given and the physical processes they are derived from are explained. Another main objekt of the report is the description of the numerical methods used as well as the input and output of the code. (orig.) [de

  6. Fukushima. Five years on - FAQs; 5 Jahre Fukushima - Fragen und Antworten

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-03-15

    On 11 March 2011, at 2:46 p.m. local time (6.46 a.m. CET), an earthquake measuring 9 on the Richter scale hit the east coast of Japan. The quake caused a tsunami, with waves as high as 38 metres, which led to large-scale flooding and destruction of roads, the power supply and other infrastructure along Japan's eastern seaboard. The earthquake and tsunami also struck several nuclear power plants. Fukushima Daiichi sustained the worst damage, triggering a chain of events which led to core meltdown, major hydrogen explosions and massive releases of radiation. Below, the Oeko-Institut answers the key questions about the disaster's timeline, latest assessments of the events, and the current situation in Fukushima.

  7. Radiation monitoring complete change by an unprecedented nuclear power plant accident

    International Nuclear Information System (INIS)

    Omura, Tomomi

    2011-01-01

    Hydrogen explosion at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company that was triggered by the tsunami generated from the Great East Japan Earthquake led to a series of disasters up to meltdown and melt-through. A large amount of discharge of radioactive substances to the environment due to the disasters marked a sea change in the situation of radiation monitoring in Japan to date. The Japanese Government took the following actions. (1) Establishment of government-led monitoring system through the setup of the Monitoring Coordination Council, (2) Decision on 'Comprehensive Monitoring Program' that implements unified comprehensive radiation monitoring and publishes the results, and (3) Law establishment for radiation monitoring by stipulating immediate implementation systems and implementation points as well as budgetary backup for this purpose. This paper describes the plans to monitor the environment, public facilities, aquatic environment, agricultural land, food, etc., as well as the future challenges. (O.A.)

  8. Preliminary design of a borax internal core-catcher for a gas cooled fast reactor

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Dorner, S.; Schumacher, G.

    1976-09-01

    Preliminary thermal calculations show that a core-catcher appears to be feasible, which is able to cope with the complete meltdown of the core and blankets of a 1,000 MWe GCFR. This core-catcher is based on borax (Na 2 B 4 O 7 ) as dissolving material of the oxide fuel and of the fission products occuring in oxide form. The borax is contained in steel boxes forming a 2.1 meter thick slab on the base of the reactor cavity inside the prestressed concrete reactor vessel, just underneath the reactor core. The fission products are dispersed in the pool formed by the liquid borax. The heat power density in the pool is conveniently reduced and the resulting heat fluxes at the borders of the pool can be safely carried away through the PCRV liner and its water cooling system. (orig.) [de

  9. Should nuclear liability limits be removed. Yes

    International Nuclear Information System (INIS)

    Haas, L.

    1985-01-01

    Arguing in favor of unlimited liability in the event of a nuclear accident, the author cites a mathematical probability of a core meltdown in the US as 45% during the next 20 years. The liability insurance carried by the nuclear industry is less than for large hotels and industrial parks, and is only a small fraction of the potential costs of damage and compensation. If nuclear technology is safe, limits are not needed. If liability is limited, it removes the incentive to improve safety and sends inaccurate price signals to utilities choosing among competing technologies. There is also the ethical aspect of shifting liability costs from ratepayers and stockholders to accident victims and general taxpayers. There are other ways to finance nuclear risks, such as a sinking fund, the removal of the nuclear exclusion in property insurance policies, and annual retrospective assessments per reactors

  10. Vapour pressure measurements over liquid UO{sub 2} and (U,Pu)O{sub 2} by laser surface heating up to 5000 K

    Energy Technology Data Exchange (ETDEWEB)

    Babelot, J F; Brumme, G D [Institut fuer Angewandte Physik, TH Darmstadt (Germany); Kinsman, P R; Ohse, R W [Commission of the European Communities, European Institute for Transuranium Elements, EURATOM (Germany)

    1977-07-01

    Nuclear reactor technology requires the vapour pressure of fast breeder reactor fuels up to 6000 K in order to estimate the energy release In hypothetical fast reactor core meltdown accident. Both theoretical and experimental efforts are needed to provide the required data. In principle PVT data can be estimated by appropriate theoretical models, extrapolating measured data, or by purely thermodynamic calculations based on the extrapolation of reliable low temperature thermodynamic data. Direct measurements require the development of new experimental techniques for the extreme temperature range of interest in nuclear technology. The various theoretical approaches are characterized by the application of models which were conceived for simple molecular liquids and by the extrapolation of low temperature vapour pressure data over several thousand degrees, leading to a range In predicted critical point temperatures from 6000 K to almost 10000 K.

  11. KATS experiments to simulate corium spreading in the EPR core catcher concept

    International Nuclear Information System (INIS)

    Eppinger, B.; Fieg, G.; Schuetz, W.; Stegmaier, U.

    2001-01-01

    In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. Quick freezing of the molten core masses is desirable to reduce release of radioactivity. Several concepts of core catcher de-vices have been proposed based on the spreading of corium melt onto flat surfaces with subsequent cooling by flooding with water. Therefore a series of experiments to investigate high temperature melt spreading on flat surfaces has been carried out using alumina-iron thermite melts as a simulant. The oxidic thermite melt is conditioned by adding other oxides to simulate a realistic corium melt as close as possible. Spreading of oxidic and metallic melts have been performed in one- and two-dimensional geometry. Substrates were chemically inert ceramic layers, dry concrete and concrete with a shallow water layer on top. (authors)

  12. Technical bases for estimating fission product behavior during LWR accidents. Technical report

    International Nuclear Information System (INIS)

    1981-06-01

    The objective of this report is to provide the Nuclear Regulatory Commission and the public with a description of the best technical information currently available for estimating the release of radioactive material during postulated reactor accidents, and to identify where gaps exist in our knowledge. This report focuses on those low probability-high consequence accidents involving severe damage to the reactor core and core meltdown that dominate the risk to the public. Furthermore, in this report particular emphasis is placed on the accident behavior of radioactive iodine, as (1) radioiodine is predicted to be a major contributor to public exposure, (2) current regulatory accident analysis procedures focus on iodine, and (3) several technical issues have been raised recently about the magnitude of iodine release. The generation, transport, and attenuation of aerosols were also investigated in some detail to assess their effect on fission product release estimates and to determine the performance of engineered safety features under accident conditions exceeding their design bases

  13. Experimental investigations of long-term interactions of molten UO2 with MgO and concrete at Argonne National Laboratory

    International Nuclear Information System (INIS)

    Stein, R.P.; Farhadieh, R.; Pedersen, D.R.; Gunther, W.H.; Purviance, R.T.

    1982-01-01

    Experimental work at Argonne is being performed to investigate the long-term molten-core-debris retention capability of the ex-vessel cavity following a postulated meltdown accident. The eventual objective of the work is to determine if normal structural material (concrete) or a specifically selected sacrificial material (MgO) located in the ex-vessel cavity region can effectively contain molten core debris. The materials under investigation at ANL are various types of concrete (limestone, basalt and magnetite) and commercially-available MgO brick. Results are presented of the status of real material experimental investigation at ANL into (1) molten UO 2 pool heat transfer, (2) long-term molten UO 2 penetration into concrete and (3) long-term molten UO 2 penetration into refractory substrates. The decay heating in the fuel has been simulated by direct electrical heating permitting the study of the long-term interaction

  14. Experimental investigations of long-term interactions of molten UO2 with MgO and concrete at Argonne National Laboratory

    International Nuclear Information System (INIS)

    Stein, R.P.; Farhadieh, R.; Pedersen, D.R.; Gunther, W.H.; Purviance, R.T.

    1982-01-01

    Experimental work at Argonne is being performed to investigate the long-term molten core debris retention capability of the ex-vessel cavity following a postulated meltdown accident. The eventual objective of the work is to determine if normal structural material (concrete) or a specifically selected sacrificial material (MgO) located in the ex-vessel cavity region can effectively contain molten core debris. The materials under investigation at ANL are various types of concrete (limestone, basalt and magnetite) and commercially-available MgO brick. Results are presented of the status of real material experimental investigation at ANL into 1) molten UO 2 pool heat transfer, 2) long-term molten UO 2 penetration into concrete and 3) long-term molten UO 2 penetration into refractory substrates. The decay heating in the fuel has been simulated by direct electrical heating permitting the study of the long-term interaction

  15. Some consideration on reviewing of WWER

    International Nuclear Information System (INIS)

    Shibata, Heki

    1993-01-01

    The main points of NPP safety are to prevent core melt-down and to mitigate the divergence of radioactive materials to the atmosphere in general. However, destroying of the reactor building may cause damages of various mechanical and other components and piping systems, and these failures may proceed to LOCA and other critical failures of safety related items. The main items that are considered in view of upgrading the existing WWER type reactors are: buildings, emergency power supply systems, anchoring devices and concrete structures, mechanical components, water storage, piping support, civil engineering structure. This pipe describes the method for improving seismic capacity of the operating NPPs and to keep their safety under seismic conditions

  16. Low cost Czochralski crystal growing technology. Near implementation of the flat plate photovoltaic cost reduction of the low cost solar array project

    Science.gov (United States)

    Roberts, E. G.

    1980-01-01

    Equipment developed for the manufacture of over 100 kg of silicon ingot from one crucible by rechanging from another crucible is described. Attempts were made to eliminate the cost of raising the furnace temperature to 250 C above the melting point of silicon by using an RF coil to melt polycrystalline silicon rod as a means of rechanging the crucible. Microprocessor control of the straight growth process was developed and domonstrated for both 4 inch and 6 inch diameter. Both meltdown and melt stabilization processes were achieved using operator prompting through the microprocessor. The use of the RF work coil in poly rod melting as a heat sink in the accelerated growth process was unsuccessful. The total design concept for fabrication and interfacing of the total cold crucible system was completed.

  17. Numerical calculation of transient field effects in quenching superconducting magnets

    CERN Document Server

    Schwerg, Nikolai; Russenschuck, Stephan

    2009-01-01

    The maximum obtainable magnetic induction of accelerator magnets, relying on normal conducting cables and iron poles, is limited to around 2 T because of ohmic losses and iron saturation. Using superconducting cables, and employing permeable materials merely to reduce the fringe field, this limit can be exceeded and fields of more than 10 T can be obtained. A quench denotes the sudden transition from the superconducting to the normal conducting state. The drastic increase in electrical resistivity causes ohmic heating. The dissipated heat yields a temperature rise in the coil and causes the quench to propagate. The resulting high voltages and excessive temperatures can result in an irreversible damage of the magnet - to the extend of a cable melt-down. The quench behavior of a magnet depends on numerous factors, e.g. the magnet design, the applied magnet protection measures, the external electrical network, electrical and thermal material properties, and induced eddy current losses. The analysis and optimizat...

  18. Use of probabilistic studies in the analysis of modifications of French nuclear power plants

    International Nuclear Information System (INIS)

    Gros, G.; Milhem, J.M.

    1985-11-01

    The 900 MWe water pressurized reactors have been designed on deterministic basis. It appeared that some safety systems had a probability of failure non negligible and that their total failure could involve, in a short-term, severe consequences. This situation led Electricite de France to propose complementary measures (control-procedures, and associated modifications). To judge the efficiency of such measures, the safety authorities thought it was advisable to rest on probabilistic studies which have been developed by the Department of Safety Analysis of the C.E.A. The contribution of such studies, in the choice of modifications by information on the weak points and in the judgement on the efficiency of these modifications by probabilistic estimation of meltdown, is illustrated with the example of electric power supplies [fr

  19. Safety of nuclear reactors - Part A - unsteady state temperature history mathematical model

    International Nuclear Information System (INIS)

    El-Shayeb, M.; Yusoff, M.Z.; Boosroh, M.H.; Ideris, F.; Hasmady Abu Hassan, S.; Bondok, A.

    2004-01-01

    A nuclear reactor structure under abnormal operations of near meltdown will be exposed to a tremendous amount of heat flux in addition to the stress field applied under normal operation. Temperature encountered in such case is assumed to be beyond 1000 Celsius degrees. A 2-dimensional mathematical model based on finite difference methods, has been developed for the fire resistance calculation of a concrete-filled square steel column with respect to its temperature history. Effects due to nuclear radiation and mechanical vibrations will be explored in a later future model. The temperature rise in each element can be derived from its heat balance by applying the parabolic unsteady state, partial differential equation and numerical solution into the steel region. Calculation of the temperature of the elementary regions needs to satisfy the symmetry conditions and the relevant material properties. The developed mathematical model is capable to predict the temperature history in the column and on the surface with respect to time. (authors)

  20. Core catcher concepts future PWR-Plants

    International Nuclear Information System (INIS)

    Alsmeyer, H.; Werle, H.

    1994-01-01

    Light water reactors of the next generation should have still greater passive safety, even in the most serious accidents. This includes the long term safe inclusion of the core inventory in the case of core meltdown accidents. The three concepts for cooling the liquefied core outside the reactor pressure vessel examined by KfK should remove the post-shutdown heat by direct contact of the melt with water. The geometric distribution of the melt increases its surface area, so that favourable conditions for heat removal from the poorly thermally-conducting melt are created and complete quick solidification occurs. The experiments examine both the relocation and distribution mechanisms of the melt and the reactions occurring when water enters. As strong interaction is possible on direct contact of the melt with water, an important aim is experimental determination and limitation of any resulting mechanical stresses. (orig./HP) [de

  1. Consequence analysis and probabilistic safety analysis of Angra-1

    International Nuclear Information System (INIS)

    Guimaraes, A.C.F.

    1987-07-01

    A methodology for determining the environmental consequences in the site of nuclear power plants, is presented. The methodology obtains as final result the 'S' site matrix, which represents the probabilities of health damage. Two types of healt damages were analysed: the early fatalities and injury. The damages are calculated from the determination of radiation doses which the population in surrounding of the site could be submitted, in the case of severe accident with the core meltdown. The accidents are defined from an initial event, leading to the failure of reactor containment. The results presented the same magnitude order when they were compared with ones obtained in studies of the Zion Nuclear Power Plant. The Angra-1 was adopted as reference reactor and the CRAC-2 computer code was used. (M.C.K.) [pt

  2. Chernobyl: Chronicle of difficult weeks [videorecording

    Energy Technology Data Exchange (ETDEWEB)

    Volodymyr, S

    1987-07-01

    1. Chernobyl : chronicle of difficult weeks. Shevchenko's film crew was the first in the disaster zone following the meltdown of the core of the Chernobyl nuclear power plant in 1986. They shot continuously for more than three months. Portions of the film are exposed with white blotches - a radiation leakage. The film demonstrates how authorities and volunteers dealt with the accident, shows the efforts to get the fire under control, to take care of patients with radiation injuries, and to evacuate about 100,000 inhabitants of the area. 2. The BAM zone : permanent residents. The Baikal-Amur Mainline (BAM) railroad in Siberia is called the longest monument to the stagnation of the Brezhnev years. The film shows the lives and fates of the people in contrast to the marches and songs praising the project.

  3. INTERNATIONAL TRADE DURING THE CRISIS. DETERMINANTS

    Directory of Open Access Journals (Sweden)

    Cristian Spiridon

    2014-06-01

    Full Text Available This article aims to analyze how the financial crisis that bursted in the mid-2008 led to a global and regional drop in trade flows. It starts from a comparison of the Great Depression shock to what happened during the Great Recession. Based on the similarities and differences found in the literature we take a simple econometric analysis to study the relationship between income, private lending and imports of goods by different countries from the financial meltdown starting point. The main findings consist of the magnitude heterogeneity of the decrease in income and credit at the regional level and on country groups according to the degree of development and the uttering of new factors influencing world trade (risk shock, increasing uncertainty, escalating non-tariff protectionist measures.

  4. Research and experience report 2008. Developments in the technical and legal basis of nuclear oversight; Erfahrungs- und Forschungsbericht 2008. Entwicklungen im Bereich der Grundlagen der nuklearen Aufsicht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-04-15

    This annual report issued by the Swiss Federal Nuclear Inspectorate (ENSI) reviews research into regulatory safety and the work done during 2008. In the area of reactor safety, research - in addition to research into materials - was concentrated primarily on safety and reliability analyses. ENSI supports projects looking at ageing mechanisms such as fatigue, corrosion, embrittlement and the development of cracks under a range of environmental conditions. Topics such as the interaction between core meltdown and water and concrete as well as the development of methods and computer codes are covered. In the area of transport and waste management, ENSI is focussing its efforts on research into the geological strata suitable for the final storage of highly radioactive, long-lived waste. Human and organisational factors and safety culture now account for an increasing part of the work of this regulatory body. Appendices present an overview of work done, international activities, publications and the basic principles of the new ENSI guidelines.

  5. Severe accidents in nuclear reactors

    International Nuclear Information System (INIS)

    Ohai, Dumitru; Dumitrescu, Iulia; Tunaru, Mariana

    2004-01-01

    The likelihood of accidents leading to core meltdown in nuclear reactors is low. The consequences of such an event are but so severe that developing and implementing of adequate measures for preventing or diminishing the consequences of such events are of paramount importance. The analysis of major accidents requires sophisticated computation codes but necessary are also relevant experiments for checking the accuracy of the predictions and capability of these codes. In this paper an overview of the severe accidents worldwide with definitions, computation codes and relating experiments is presented. The experimental research activity of severe accidents was conducted in INR Pitesti since 2003, when the Institute jointed the SARNET Excellence Network. The INR activity within SARNET consists in studying scenarios of severe accidents by means of ASTEC and RELAP/SCDAP codes and conducting bench-scale experiments

  6. Tchernobyl accident

    International Nuclear Information System (INIS)

    1986-06-01

    First, R.M.B.K type reactors are described. Then, safety problems are dealt with reactor control, behavior during transients, normal loss of power and behavior of the reactor in case of leak. A possible scenario of the accident of Tchernobyl is proposed: events before the explosion, possible initiators, possible scenario and events subsequent to the core meltdown (corium-concrete interaction, interaction with the groundwater table). An estimation of the source term is proposed first from the installation characteristics and the supposed scenario of the accident, and from the measurements in Europe; radiological consequences are also estimated. Radioactivity measurements (Europe, Scandinavia, Western Europe, France) are given in tables (meteorological maps and fallouts in Europe). Finally, a description of the site is given [fr

  7. Definition of containment failure

    International Nuclear Information System (INIS)

    Cybulskis, P.

    1982-01-01

    Core meltdown accidents of the types considered in probabilistic risk assessments (PRA's) have been predicted to lead to pressures that will challenge the integrity of containment structures. Review of a number of PRA's indicates considerable variation in the predicted probability of containment failure as a function of pressure. Since the results of PRA's are sensitive to the prediction of the occurrence and the timing of containment failure, better understanding of realistic containment capabilities and a more consistent approach to the definition of containment failure pressures are required. Additionally, since the size and location of the failure can also significantly influence the prediction of reactor accident risk, further understanding of likely failure modes is required. The thresholds and modes of containment failure may not be independent

  8. IRSN research programs concerning reactor safety

    International Nuclear Information System (INIS)

    Bardelay, J.

    2005-01-01

    This paper is made up of 3 parts. The first part briefly presents the missions of IRSN (French research institute on nuclear safety), the second part reviews the research works currently led by IRSN in the following fields : -) the assessment of safety computer codes, -) thermohydraulics, -) reactor ageing, -) reactivity accidents, -) loss of coolant, -) reactor pool dewatering, -) core meltdown, -) vapor explosion, and -) fission product release. In the third part, IRSN is shown to give a major importance to experimental programs led on research or test reactors for collecting valid data because of the complexity of the physical processes that are involved. IRSN plans to develop a research program concerning the safety of high or very high temperature reactors. (A.C.)

  9. Degradation in steam of 60 cm-long B{sub 4}C control rods

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez, C., E-mail: christina.dominguez@irsn.fr; Drouan, D.

    2014-08-01

    In the framework of nuclear reactor core meltdown accident studies, the degradation of boron carbide control rod segments exposed to argon/steam atmospheres was investigated up to about 2000 °C in IRSN laboratories. The sequence of the phenomena involved in the degradation has been found to take place as expected. Nevertheless, the ZrO{sub 2} oxide layer formed on the outer surface of the guide tube was very protective, significantly delaying and limiting the guide tube failure and therefore the boron carbide pellet oxidation. Contrary to what was expected, the presence of the control rod decreases the hydrogen release instead of increasing it by additional oxidation of boron compounds. Boron contents up to 20 wt.% were measured in metallic mixtures formed during degradation. It was observed that these metallic melts are able to attack the surrounding fuel rods, which could have consequences on fuel degradation and fission product release kinetics during severe accidents.

  10. Anticipated transients without scram for light water reactors: implications for liquid metal fast breeder reactors

    International Nuclear Information System (INIS)

    Kastenberg, W.E.; Solomon, K.A.

    1979-07-01

    In the design of light water reactors (LWRs), protection against anticipated transients (e.g., loss of normal electric power and control rod withdrawal) is provided by a highly reliable scram, or shutdown system. If this system should become inoperable, however, the transient could lead to a core meltdown. The Nuclar Regulatory Commission (NRC) has proposed, in NUREG-0460 [1], new requirements (or acceptance criteria) for anticipated transients without scram (ATWS) events and the manner in which they could be considered in the design and safety evaluation of LWRs. This note assesses the potential impact of the proposed LWR-ATWS criteria on the liquid metal fast breeder reactor (LMFBR) safety program as represented by the Clinch River Breeder Reactor Plant

  11. Measuring Public Acceptance of Nuclear Technology with Big data

    International Nuclear Information System (INIS)

    Roh, Seugkook

    2015-01-01

    Surveys can be conducted only on people in specific region and time interval, and it may be misleading to generalize the results to represent the attitude of the public. For example, opinions of a person living in metropolitan area, far from the dangers of nuclear reactors and enjoying cheap electricity produced by the reactors, and a person living in proximity of nuclear power plants, subject to tremendous damage should nuclear meltdown occur, certainly differs for the topic of nuclear generation. To conclude, big data is a useful tool to measure the public acceptance of nuclear technology efficiently (i.e., saves cost, time, and effort of measurement and analysis) and this research was able to provide a case for using big data to analyze public acceptance of nuclear technology. Finally, the analysis identified opinion leaders, which allows target-marketing when policy is executed

  12. Risk of the research reactor BER II in Berlin; Risiken des Berliner Experimentierreaktors BER II

    Energy Technology Data Exchange (ETDEWEB)

    Paulitz, Henrik; Hoevener, Barbara; Rosen, Alex

    2015-04-20

    The research reactor BER II is sited at the periphery of Berlin in the neighborhood of residential areas. The operational license is limited until December 31, 2019. The reactor is funded by the Federal Government (90%) and the city of Berlin (10%). The stress test has shown that the reactor is not secured against an aircraft crash (airliner or fast flying military jet), meltdown with remarkable radiological consequences to the public would be the consequence. Further hazards result from the radioactive waste transport, explosions and fires. The emergency measures cannot be considered to be sufficient. The city of Berlin would not be able to fulfill the required measures in case of a radiation accident.

  13. Provisions for containment venting in Germany

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelm, J.G.

    1997-08-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab.

  14. Economic inequality and economic crisis: a challenge for social workers.

    Science.gov (United States)

    Goldberg, Gertrude Schaffner

    2012-07-01

    To social workers, extreme economic inequality is primarily a violation of social justice, but this article shows how growing economic inequality since the mid-1970s was not only unjust, but also dysfunctional to the U.S. economy and linked to the recent economic crisis with its devastating effects, particularly on the social work clientele. The article identifies interrelated changes in ideology, the market economy, and government policies since the mid-1970s; contrasts the political economy of this period with the preceding post-World War II decades when the trend was toward a "shared prosperity"; and shows how increased economic inequality and political consequences that undermined democracy itself contributed to the economic meltdown. The analysis has implications for the direction of social reform and for broadening the constituency of social movements in pursuit of the social work mission of social justice. How social workers can contribute to such movements and to a reduction of economic and political inequality is explored.

  15. Twenty-five years of environmental radionuclide concentrations near a nuclear power plant.

    Science.gov (United States)

    Harris, Charles; Kreeger, Danielle; Patrick, Ruth; Palms, John

    2015-05-01

    The areas in and along a 262-km length of the Susquehanna River in Pennsylvania were monitored for the presence of radioactive materials. This study began two months after the 1979 Three Mile Island (TMI) partial reactor meltdown; it spanned the next 25 y. Monitoring points included stations at the PPL Susquehanna and TMI nuclear power plants. Monthly gamma measurements document concentrations of radionuclides from natural and anthropogenic sources. During this study, various series of gamma-emitting radionuclide concentration measurements were made in many general categories of animals, plants, and other inorganic matter. Sampling began in 1979 before the first start-up of the PPL Susquehanna power plant. Although all species were not continuously monitored for the entire period, an extensive database was compiled. In 1986, the ongoing measurements detected fallout from the Chernobyl nuclear accident. These data may be used in support of dose or environmental transport calculations.

  16. Safety-related LWR research. Annual report 1989

    International Nuclear Information System (INIS)

    1990-11-01

    The main topics in this annual report 1989 are phenomena of heavy fuel damage and single aspects of a core meltdown accident. The examined single aspects refer to aerosol behavior and filter engineering and to methods for assessment and minimization of the radiological consequences of reactor accidents. Different contributions to selected, safety-related problems of an advanced pressurized-water reactor complete the topic spectrum. The annual report 1989 describes the progress of the research work wich was carried out in the area of safety research by institutes and departments of the KfK, and on behalf of the KfK by external institutions. The individual contributions represent the status of work at the end of the year under review, 1989. (orig./HP) [de

  17. Numerical predictions of natural convection in a uniformly heated pool

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Cho, D.H.

    1993-01-01

    In the event of a core meltdown accident, one of the accident progression paths is fuel relocation to the lower reactor plenum. In the heavy-water new production reactor (NPR-HWR) design, the reactor cavity is flooded with water. In such a design, decay heat removal to the water in the reactor cavity and thence to the containment may be adequate to keep the reactor vessel temperature below failure limits. If this is the case, the accident progression can be arrested by retaining a coolable corium configuration in the lower reactor plenum. The strategy of reactor cavity flooding to prevent reactor vessel failure from molten corium relocation to the reactor vessel lower head has also been considered for commercial pressurized water reactors

  18. Selected source term topics. Report to CSNI by an OECD/NEA Group of experts

    International Nuclear Information System (INIS)

    1987-04-01

    CSNI Report 136 summarizes the results of the work performed by the Group of Experts on the Source Term and Environmental Consequences (PWG4) during the period extending from 1983 and 1986. This report is complementary to Part 1, 'Technical Status of the Source Term' of CSNI Report 135, 'Report to CSNI on Source Term Assessment, Containment atmosphere control systems, and accident consequences'; it considers in detail a number of very specific issues thought to be important in the source term area. It consists of: an executive summary (prepared by the Chairman of the Group), a section on conclusions and recommendations, and five technical chapters (fission product chemistry in the primary circuit of a LWR during severe accidents; resuspension/re-entrainment of aerosols in LWRs following a meltdown accident; iodine chemistry under severe accident conditions; effects of combustion, steam explosions and pressurized melt ejection on fission product behaviour; radionuclide removal by pool scrubbing), a technical annex and two appendices

  19. Bankruptcy cascades in interbank markets.

    Directory of Open Access Journals (Sweden)

    Gabriele Tedeschi

    Full Text Available We study a credit network and, in particular, an interbank system with an agent-based model. To understand the relationship between business cycles and cascades of bankruptcies, we model a three-sector economy with goods, credit and interbank market. In the interbank market, the participating banks share the risk of bad debits, which may potentially spread a bank's liquidity problems through the network of banks. Our agent-based model sheds light on the correlation between bankruptcy cascades and the endogenous economic cycle of booms and recessions. It also demonstrates the serious trade-off between, on the one hand, reducing risks of individual banks by sharing them and, on the other hand, creating systemic risks through credit-related interlinkages of banks. As a result of our study, the dynamics underlying the meltdown of financial markets in 2008 becomes much better understandable.

  20. Decontamination and decommissioning plan for processing contaminated NaK at the INEL

    Energy Technology Data Exchange (ETDEWEB)

    LaRue, D.M.; Dolenc, M.R.

    1986-09-01

    This decontamination and decommissioning (D&D) plan describes the work elements and project management plan for processing four containers of contaminated sodium/potassium (NaK) and returning the Army Reentry Vehicle Facility Site (ARVFS) to a reusable condition. The document reflects the management plan for this project before finalizing the conceptual design and preliminary prototype tests of the reaction kinetics. As a result, the safety, environmental, and accident analyses are addressed as preliminary assessments before completion at a later date. ARVFS contains an earth-covered bunker, a cylindrical test pit and metal shed, and a cable trench connecting the two items. The bunker currently stores the four containers of NaK from the meltdown of the EBR-1 Mark II core. The D&D project addressed in this plan involves processing the contaminated NaK and returning the ARVFS to potential reuse after cleanup.

  1. Decontamination and decommissioning plan for processing contaminated NaK at the INEL

    Energy Technology Data Exchange (ETDEWEB)

    LaRue, D.M.; Dolenc, M.R.

    1986-09-01

    This decontamination and decommissioning (D D) plan describes the work elements and project management plan for processing four containers of contaminated sodium/potassium (NaK) and returning the Army Reentry Vehicle Facility Site (ARVFS) to a reusable condition. The document reflects the management plan for this project before finalizing the conceptual design and preliminary prototype tests of the reaction kinetics. As a result, the safety, environmental, and accident analyses are addressed as preliminary assessments before completion at a later date. ARVFS contains an earth-covered bunker, a cylindrical test pit and metal shed, and a cable trench connecting the two items. The bunker currently stores the four containers of NaK from the meltdown of the EBR-1 Mark II core. The D D project addressed in this plan involves processing the contaminated NaK and returning the ARVFS to potential reuse after cleanup.

  2. Thermodynamic Data to Model the Interaction Between Coolant and Fuel in Gen IV Sodium Cooled Fast Reactors

    International Nuclear Information System (INIS)

    Dinsdale, Alan; Gisby, John; Davies, Hugh; Konings, Rudy; Benes, Ondrej

    2013-06-01

    Understanding the behaviour of nuclear fuels in various environments is vital to the design and safe operation of nuclear reactors. While this is true if the reactor is operating within its design specification, it is even more so if accidents occur and the fuel is exposed to unexpected temperatures, pressures or chemical environments. It is clearly hazardous and costly to explore all such scenarios experimentally and therefore it is necessary to undertake modelling where possible using well-grounded theoretical approaches. This paper will show examples of where calculations of chemical and phase equilibria have been applied successfully to the long term storage of nuclear waste, phase formation during core meltdown and prediction of fission product release into the atmosphere. It will also highlight the development of thermodynamic data carried out during the European Metrology Research Project Metrofission required to model the potential interaction between the coolant, nuclear fuel, containment materials and atmosphere of a sodium cooled fast reactor. (authors)

  3. PWR severe accident mitigation measures, the french point of view

    International Nuclear Information System (INIS)

    Duco, J.; L'Homme, A.; Queniart, D.

    1990-01-01

    French studies have early considered the fact that, despite all the precautions taken, the possibility of severe accidents cannot be absolutely excluded; these accidents include core meltdown and a more or less significant loss, at an early or later stage, of the confinement of the radioactive substances in the containment. For a given scenario, one can almost always imagine a more severe scenario by postulating additional failures, but it is obvious that, as the severity of the imagined scenario increases, the probability of its occurrence tends towards zero. However, it does not appear reasonable to attempt to set a probability threshold below which the scenarios should be excluded. First of all, the higher the improbability of the scenarios, the greater the uncertainty in the calculation of their probability, with the result that the calculation is not very meaningful. Secondly, and more importantly, this approach ignores the essential problem of accident situation management. From the outset, French studies have been focused on controlling the development of these situations and mitigating their consequences by means of a series of appropriate actions involving, on the one hand, optimum use of the resources available in the installation during the course of the accident and, on the other hand, the taking of protective measures for the population. To attempt to prevent an initial event to degenerate into a severe accident leading to core meltdown if the proper actions are not taken, Electricite de France has proposed a new operating procedure based on the characterization of every possible cooling state of the core

  4. Effects of Emulsifier, Overrun and Dasher Speed on Ice Cream Microstructure and Melting Properties.

    Science.gov (United States)

    Warren, Maya M; Hartel, Richard W

    2018-03-01

    Ice cream is a multiphase frozen food containing ice crystals, air cells, fat globules, and partially coalesced fat globule clusters dispersed in an unfrozen serum phase (sugars, proteins, and stabilizers). This microstructure is responsible for ice cream's melting characteristics. By varying both formulation (emulsifier content and overrun) and processing conditions (dasher speed), the effects of different microstructural elements, particularly air cells and fat globule clusters, on ice cream melt-down properties were studied. Factors that caused an increase in shear stress within the freezer, namely increasing dasher speed and overrun, caused a decrease in air cell size and an increase in extent of fat destabilization. Increasing emulsifier content, especially of polysorbate 80, caused an increase in extent of fat destabilization. Both overrun and fat destabilization influenced drip-through rates. Ice creams with a combination of low overrun and low fat destabilization had the highest drip-through rates. Further, the amount of remnant foam left on the screen increased with reduced drip-through rates. These results provide a better understanding of the effects of microstructure components and their interactions on drip-through rate. Manipulating operating and formulation parameters in ice cream manufacture influences the microstructure (air cells, ice crystals, and fat globule clusters). This work provides guidance on which parameters have most effect on air cell size and fat globule cluster formation. Further, the structural characteristics that reduce melt-down rate were determined. Ice cream manufacturers will use these results to tailor their products for the desired quality attributes. © 2018 Institute of Food Technologists®.

  5. Behavior of an indigenously fabricated transferred arc plasma furnace for smelting studies

    Science.gov (United States)

    A, K. MANDAL; R, K. DISHWAR; O, P. SINHA

    2018-03-01

    The utilization of industrial solid waste for metal recovery requires high-temperature tools due to the presence of silica and alumina, which is reducible at high temperature. In a plasma arc furnace, transferred arc plasma furnace (TAP) can meet all requirements, but the disadvantage of this technology is the high cost. For performing experiments in the laboratory, the TAP was fabricated indigenously in a laboratory based on the different inputs provided in the literature for the furnace design and fabrication. The observed parameters such as arc length, energy consumption, graphite electrode consumption, noise level as well as lining erosion were characterized for this fabricated furnace. The nitrogen plasma increased by around 200 K (200 °C) melt temperature and noise levels decreased by ∼10 dB compared to a normal arc. Hydrogen plasma offered 100 K (100 °C) higher melt temperature with ∼5 dB higher sound level than nitrogen plasma. Nitrogen plasma arc melting showed lower electrode and energy consumption than normal arc melting, whereas hydrogen plasma showed lower energy consumption and higher electrode consumption in comparison to nitrogen plasma. The higher plasma arc temperature resulted in a shorter meltdown time than normal arc with smoother arcing. Hydrogen plasma permitted more heats, reduced meltdown time, and lower energy consumption, but with increased graphite consumption and crucible wear. The present study showed that the fabricated arc plasma is better than the normal arc furnace with respect to temperature generation, energy consumption, and environmental friendliness. Therefore, it could be used effectively for smelting-reduction studies.

  6. Integrated CFD investigation of heat transfer enhancement using multi-tray core catcher in SFR

    International Nuclear Information System (INIS)

    Rakhi; Sharma, Anil Kumar; Velusamy, K.

    2017-01-01

    Highlights: • Heat transfer enhancement using multi-tray core catcher for SFR is investigated. • The capability of a single core collector tray is estimated. • Double and triple collector trays with innovative designs is discussed. • Provision of openings in the trays contributed to enhanced natural circulation. - Abstract: To render future SFR more robust and safe, certain BDBE have been considered in the recent years. A Core Disruptive Accident leading to a whole core meltdown scenario has gained the interest of researchers. Various design concepts and safety measures have been suggested and incorporated in design to address such a low probability scenario. A core catcher concept, in particular, has proved to be inevitable as an in-vessel core retention device in SFR for safe retention of core debris arising out after the severe accident. This study aims to analyse the cooling capability of the innovative design concept of core catcher to remove decay heat of degraded core after the accident. First, the capability of single collection tray is established and then the study is extended to two and three collection trays with different design concepts. Transient forms of governing equations of mass, momentum and energy conservations along with k-ε turbulence model are solved by finite volume based CFD solver. Boussinesq approximation is invoked to model buoyancy in sodium. The study shows that a single collection tray is capable of removing up to 20 MW decay heat load in a typical 500 MWe pool type SFR. Further, studies are carried out to improve the natural circulation of sodium around the source, in the lower plenum and to distribute core debris of the whole core to multiple collection trays. It is found that the double and triple collection trays can accommodate decay loads up to 29 MW. Provision of openings in the collection trays has proved to be effective in improving the heat transfer and sodium flow as well as in distributing the core debris to the

  7. Accident-tolerant control rod

    International Nuclear Information System (INIS)

    Ohta, Hirokazu; Sawabe, Takashi; Ogata, Takanari

    2013-01-01

    Boron carbide (B 4 C) and hafnium (Hf) metal are used for the neutron absorber materials of control rods in BWRs, and silver-indium-cadmium (Ag-In-Cd) alloy is used in PWRs. These materials are clad with stainless steel. The eutectic point of B 4 C and iron (Fe) is about 1150 deg. C and the melting point of Ag-In-Cd alloy is about 800 deg. C, which are lower than the temperature of zircaloy - steam reaction increases rapidly (∼1200 deg. C). Accordingly, it is possible that the control rods melt and collapse before the reactor core is significantly damaged in the case of severe accidents. Since the neutron absorber would be separated from the fuels, there is a risk of re-criticality, when pure water or seawater is injected for emergency cooling. In order to ensure sub-criticality and extend options of emergency cooling in the course of severe accidents, a concept of accident-tolerant control rod (ACT) has been derived. ACT utilises a new absorber material having the following properties: - higher neutron absorption than current control rod; - higher melting or eutectic temperature than 1200 deg. C where rapid zircaloy oxidation occurs; - high miscibility with molten fuel materials. The candidate of a new absorber material for ATC includes gadolinia (Gd 2 O 3 ), samaria (Sm 2 O 3 ), europia (Eu 2 O 3 ), dysprosia (Dy 2 O 3 ), hafnia (HfO 2 ). The melting point of these materials and the liquefaction temperature with Fe are higher than the rapid zircaloy oxidation temperature. ACT will not collapse before the core melt-down. After the core melt-down, the absorber material will be mixed with molten fuel material. The current absorber materials, such as B 4 C, Hf and Ag-In-Cd, are charged at the tip of ATC in which the neutron flux is high, and a new absorber material is charged in the low-flux region. This design could minimise the degradation of a new absorber material by the neutron absorption and the influence of ATC deployment on reactor control procedure. As a

  8. LWR safety research in the Federal Republic of Germany

    International Nuclear Information System (INIS)

    Seipel, H.G.

    1977-01-01

    The paper gives a review of the German LWR safety research programme. It describes how the programme was initiated and informs on its goals, development andpractical realization, and indicates how it is bound up with international collaboration. The contribution so far made by the programme to an enhancement of the understanding of major safety problems and to the improvement of safety technology is demonstrated by means of a few selected examples. Experiments relating to loss-of--coolant accidents have deepened our understanding of the heat transfer in the reactor core during blowdown as well as during the flooding phase. Investigations of the dynamic effects going on in dry full pressure containments and pressure suppression systems, following a loss-of--coolant accident, have indicated that existing computer models cannot satisfactorily predict all relevant physical phenomena. Yet, the experimental results obtained constitute a sufficient basis for safe containment design. Research work on core meltdown accidents has identified the particular importance of the type of concrete used for the containment structures and its foundation. If basaltic concrete is used, a substantial fission product release to the environment is extremely unlikely even in the case of a core meltdown accident. At least, it would take place much later than was previously assumed. Resrach on the safety of pressurized components has been concentrated on the problem of cracks in the heat-affected zone of welds. New methods were developed for the detection and analysis of the acceptability of microcrack fields. Additional investigations of specimens and components to increase the understanding of the long-term behaviour of components with microcracks are envisaged in the frame of a new major project on ''component safety''. Considerable progress has been made in the development of methods for automatic remote-control volumetric testing of reactor pressure vessels using ultrasonic techniques

  9. Fukushima Nuclear Accident, the Third International Severe Nuclear Power Plant Accident

    International Nuclear Information System (INIS)

    Rashad, S.M.

    2013-01-01

    Japan is the world's third largest power user. Japan's last remaining nuclear reactor shutdown on Saturday 4 Th of May 2012 leaving the country entirely nuclear free. All of 50 of the nation's operable reactors (not counting for the four crippled reactors at Fukushima) are now offline. Before last year's Fukushima nuclear disaster, the country obtained 30% of its energy from nuclear plants, and had planned to produce up to 50% of its power from nuclear sources by 2030. Japan declared states of emergency for five nuclear reactors at two power plants after the units lost cooling ability in the aftermath of Friday 11 March 2011 powerful earthquake. Thousands of (14000) residents were immediately evacuated as workers struggled to get the reactors under control to prevent meltdowns. On March 11 Th, 2011, Japan experienced a sever earthquake resulting in the shutdown of multiple reactors. At Fukushima Daiichi site, the earthquake caused the loss of normal Ac power. In addition it appeals that the ensuing tsunami caused the loss of emergency Ac power at the site. Subsequent events caused damage to fuel and radiological releases offsite. The spent fuel problem is a wild card in the potentially catastrophic failure of Fukushima power plant. Since the Friday's 9.0 earthquake, the plant has been wracked by repeated explosions in three different reactors. Nuclear experts emphasized there are significant differences between the unfolding nuclear crisis at Fukushima and the events leading up to the Chernobyl disaster in 1986. The Chernobyl reactor exploded during a power surge while it was in operation and released a major cloud of radiation because the reactor had no containment structure around to. At Fukushima, each reactor has shutdown and is inside a 20 cm-thick steel pressure vessel that is designed to contain a meltdown. The pressure vessels themselves are surrounded by steel-lined, reinforced concrete shells. Chernobyl disaster was classified 7 on the International

  10. The risk of a major nuclear accident: calculation and perception of probabilities

    International Nuclear Information System (INIS)

    Leveque, Francois

    2013-07-01

    The accident at Fukushima Daiichi, Japan, occurred on 11 March 2011. This nuclear disaster, the third on such a scale, left a lasting mark in the minds of hundreds of millions of people. Much as Three Mile Island or Chernobyl, yet another place will be permanently associated with a nuclear power plant which went out of control. Fukushima Daiichi revived the issue of the hazards of civil nuclear power, stirring up all the associated passion and emotion. The whole of this paper is devoted to the risk of a major nuclear accident. By this we mean a failure initiating core meltdown, a situation in which the fuel rods melt and mix with the metal in their cladding. Such accidents are classified as at least level 5 on the International Nuclear Event Scale. The Three Mile Island accident, which occurred in 1979 in the United States, reached this level of severity. The explosion of reactor 4 at the Chernobyl plant in Ukraine in 1986 and the recent accident in Japan were classified as class 7, the highest grade on this logarithmic scale. The main difference between the top two levels and level 5 relates to a significant or major release of radioactive material to the environment. In the event of a level-5 accident, damage is restricted to the inside of the plant, whereas, in the case of level-7 accidents, huge areas of land, above or below the surface, and/or sea may be contaminated. Before the meltdown of reactors 1, 2 and 3 at Fukushima Daiichi, eight major accidents affecting nuclear power plants had occurred worldwide. This is a high figure compared with the one calculated by the experts. Observations in the field do not appear to fit the results of the probabilistic models of nuclear accidents produced since the 1970's. Oddly enough the number of major accidents is closer to the risk as perceived by the general public. In general we tend to overestimate any risk relating to rare, fearsome accidents. What are we to make of this divergence? How are we to reconcile

  11. Behavior of LWR fuel elements under accident conditions

    International Nuclear Information System (INIS)

    Albrecht, H.; Bocek, M.; Erbacher, F.; Fiege, A.; Fischer, M.; Hagen, S.; Hofmann, P.; Holleck, H.; Karb, E.; Leistikow, S.; Melang, S.; Ondracek, G.; Thuemmler, F.; Wiehr, K.

    1977-01-01

    to evaluate the influence of irradiation and high burnup on fuel failure mechanisms during accident conditions. Under the extreme hypothetical assumption that in the case of a LOCA simultaneously all emergency core cooling systems fail, the consequences of a core meltdown accident and the possibilities to mitigate the consequences are investigated. Results are described on the meltdown behavior of LWR fuel rods, on the reaction behavior of mixtures of molten core components, and the most important core melt properties, on the interaction process of core melts with the concrete structure of a reactor and the associated fission product release

  12. Parent perceptions of the quality of life of pet dogs living with neuro-typically developing and neuro-atypically developing children: An exploratory study.

    Directory of Open Access Journals (Sweden)

    Sophie S Hall

    Full Text Available There is growing scientific and societal recognition of the role that pet dogs can play in healthy development of children; both those who are neuro-typically developing and those who live with a neuro-developmental disorder, such as autism or attention deficit hyperactivity disorder. However, little attention has been paid to how living with children positively and negatively affects quality of life of a pet dog. In this exploratory study we conducted semi-structured interviews with parents of neuro-typically developing children (n = 18 and those with a neuro-developmental disorder (n = 18 who owned a pet dog, until no new factors were identified. Living with children brought potentially positive benefits to the dog's life including: imposition of a routine, participation in recreational activities and the development of a strong bond between the child and the dog. The importance of maintaining a routine was particularly prevalent in families with children with neuro-developmental disorders. Potential negative factors included having to cope with child meltdowns and tantrums, over stimulation from child visitors, harsh contact and rough and tumble play with the child. The regularity and intensity of meltdowns and tantrums was particularly evident in responses from parents with children with a neuro-developmental disorder. However, child visitors and rough play and contact were mentioned similarly across the groups. Protective factors included having a safe haven for the dog to escape to, parent's awareness of stress signs and child education in dog-interaction. Parents were also asked to complete a stress response scale to provide an initial quantitative comparison of stress responses between dogs living with the two family-types. Parents with neuro-typically developing children more frequently observed their dog rapidly running away from a situation and less frequently observed their dog widening their eyes, than parents with children with a

  13. Parent perceptions of the quality of life of pet dogs living with neuro-typically developing and neuro-atypically developing children: An exploratory study.

    Science.gov (United States)

    Hall, Sophie S; Wright, Hannah F; Mills, Daniel S

    2017-01-01

    There is growing scientific and societal recognition of the role that pet dogs can play in healthy development of children; both those who are neuro-typically developing and those who live with a neuro-developmental disorder, such as autism or attention deficit hyperactivity disorder. However, little attention has been paid to how living with children positively and negatively affects quality of life of a pet dog. In this exploratory study we conducted semi-structured interviews with parents of neuro-typically developing children (n = 18) and those with a neuro-developmental disorder (n = 18) who owned a pet dog, until no new factors were identified. Living with children brought potentially positive benefits to the dog's life including: imposition of a routine, participation in recreational activities and the development of a strong bond between the child and the dog. The importance of maintaining a routine was particularly prevalent in families with children with neuro-developmental disorders. Potential negative factors included having to cope with child meltdowns and tantrums, over stimulation from child visitors, harsh contact and rough and tumble play with the child. The regularity and intensity of meltdowns and tantrums was particularly evident in responses from parents with children with a neuro-developmental disorder. However, child visitors and rough play and contact were mentioned similarly across the groups. Protective factors included having a safe haven for the dog to escape to, parent's awareness of stress signs and child education in dog-interaction. Parents were also asked to complete a stress response scale to provide an initial quantitative comparison of stress responses between dogs living with the two family-types. Parents with neuro-typically developing children more frequently observed their dog rapidly running away from a situation and less frequently observed their dog widening their eyes, than parents with children with a neuro

  14. Turning up the volume on mutational pressure: Is more of a good thing always better? (A case study of HIV-1 Vif and APOBEC3

    Directory of Open Access Journals (Sweden)

    Wong Joseph K

    2008-03-01

    Full Text Available Abstract APOBEC3G and APOBEC3F are human cytidine deaminases that serve as innate antiviral defense mechanisms primarily by introducing C-to-U changes in the minus strand DNA of retroviruses during replication (resulting in G-to-A mutations in the genomic sense strand sequence. The HIV-1 Vif protein counteracts this defense by promoting the proteolytic degradation of APOBEC3G and APOBEC3F in the host cell. In the absence of Vif expression, APOBEC3 is incorporated into HIV-1 virions and the viral genome undergoes extensive G-to-A mutation, or "hypermutation", typically rendering it non-viable within a single replicative cycle. Consequently, Vif is emerging as an attractive target for pharmacological intervention and therapeutic vaccination. Although a highly effective Vif inhibitor may result in mutational meltdown of the viral quasispecies, a partially effective Vif inhibitor may accelerate the evolution of drug resistance and immune escape due to the codon structure and recombinogenic nature of HIV-1. This hypothesis rests on two principal assumptions which are supported by experimental evidence: a there is a dose response between intracellular APOBEC concentration and degree of viral hypermutation, and, b HIV-1 can tolerate an elevated mutation rate, and a true error or extinction threshold is as yet undetermined. Rigorous testing of this hypothesis will have timely and critical implications for the therapeutic management of HIV/AIDS, and delve into the complexities underlying the induction of lethal mutagenesis in a viral pathogen.

  15. A high-throughput investigation of Fe-Cr-Al as a novel high-temperature coating for nuclear cladding materials.

    Science.gov (United States)

    Bunn, Jonathan Kenneth; Fang, Randy L; Albing, Mark R; Mehta, Apurva; Kramer, Matthew J; Besser, Matthew F; Hattrick-Simpers, Jason R

    2015-07-10

    High-temperature alloy coatings that can resist oxidation are urgently needed as nuclear cladding materials to mitigate the danger of hydrogen explosions during meltdown. Here we apply a combination of computationally guided materials synthesis, high-throughput structural characterization and data analysis tools to investigate the feasibility of coatings from the Fe–Cr–Al alloy system. Composition-spread samples were synthesized to cover the region of the phase diagram previous bulk studies have identified as forming protective oxides. The metallurgical and oxide phase evolution were studied via in situ synchrotron glancing incidence x-ray diffraction at temperatures up to 690 K. A composition region with an Al concentration greater than 3.08 at%, and between 20.0 at% and 32.9 at% Cr showed the least overall oxide growth. Subsequently, a series of samples were deposited on stubs and their oxidation behavior at 1373 K was observed. The continued presence of a passivating oxide was confirmed in this region over a period of 6 h.

  16. Propagation calculation for reactor cases

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yanhua [School of Power and Energy Engineering, Shanghai Jiao Tong Univ., Shanghai (China); Moriyama, K.; Maruyama, Y.; Nakamura, H.; Hashimoto, K. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-11-01

    The propagation of steam explosion for real reactor geometry and conditions are investigated by using the computer code JASMINE-pro. The ex-vessel steam explosion is considered, which is described as follow: during the accident of reactor core meltdown, the molten core melts a hole at the bottom of reactor vessel and causes the higher temperature core fuel being leaked into the water pool below reactor vessel. During the melt-water mixing interaction process, the high temperature melt evaporates the cool water at an extreme high rate and might induce a steam explosion. A steam explosion could experience first the premixing phase and then the propagation explosion phase. For a propagation calculation, we should know the information about the initial fragmentation time, the total melt mass, premixing region size, initial void fraction and distribution of the melt volume fraction, and so on. All the initial conditions used in this calculation are based on analyses from some simple assumptions and the observation from the experiments. The results show that the most important parameter for the initial condition of this phase is the total mass and its initial distribution. This gives the requirement for a premixing calculation. On the other hand, for higher melt volume fraction case, the fragmentation is strong so that the local pressure can exceed over the EOS maximum pressure of the code, which lead to the incorrect calculation or divergence of the calculation. (Suetake, M.)

  17. Evaluation Of The Exclusion And Low Population Areas Around A Nuclear Power Plant

    International Nuclear Information System (INIS)

    Tawfik, F.S.

    2011-01-01

    Being adjacent to the nuclear power plant (NPP) the exclusion area (EA) is the area of greatest importance. It essentially defines a buffer zone where the public has no access. It helps to define the fenced plant area, the site area and the public area. Also, the low population area is the area immediately surrounding the exclusion area near a licensed reactor in terms of public safety and the ability of residents to get away from the plant in an emergency. This study clarifies their significance and reviews the international approach on them. Assuming the nuclear power plant site at the north coast of Egypt, the exclusion area and low population area are determined according to CFR (2002). In this method, a maximum possible amount of radioactivity release (called a source term) should be assumed. The boiling water reactor (BWR) with a power 1000 MW was used to carry the calculation and assuming a severe loss of coolant accident with meltdown of reactor. The site specific data have been collected, investigated and processed. The effect of the degree of atmospheric stability and building width of the plant were examined. The proceeding factors that control the determination of exclusion area and low population area should be taken into consideration in the site evaluation stage and design basis of NPP to set a minimum distances for them

  18. Summary of NRC LWR safety research programs on fuel behavior, metallurgy/materials and operational safety

    International Nuclear Information System (INIS)

    Bennett, G.L.

    1979-09-01

    The NRC light-water reactor safety-research program is part of the NRC regulatory program for ensuring the safety of nuclear power plants. This paper summarizes the results of NRC-sponsored research into fuel behavior, metallurgy and materials, and operational safety. The fuel behavior research program provides a detailed understanding of the response of nuclear fuel assemblies to postulated off-normal or accident conditions. Fuel behavior research includes studies of basic fuel rod properties, in-reactor tests, computer code development, fission product release and fuel meltdown. The metallurgy and materials research program provides independent confirmation of the safe design of reactor vessels and piping. This program includes studies on fracture mechanics, irradiation embrittlement, stress corrosion, crack growth, and nondestructive examination. The operational safety research provides direct assistance to NRC officials concerned with the operational and operational-safety aspects of nuclear power plants. The topics currently being addressed include qualification testing evaluation, fire protection, human factors, and noise diagnostics

  19. Safety characteristics of small heat producing reactors

    International Nuclear Information System (INIS)

    Seifritz, W.

    1987-10-01

    The primary objectives of protection in nuclear power plants are the possibility to shut the reactor down in case of emergency and keep it subcritical in the long run, the existence of a heat sink for post-decay heat removal in order to avoid overheating, let alone core meltdown, and the containment of radioactivity within the barriers designed for this purpose, thus preventing significant activity release. In principle, these objectives can be met in various ways, namely by active, passive or inherent technical safeguards systems. In practice, a mixture of these approaches is employed in almost all cases. What matters in the end is the assessment of the overall concept, not of some outstanding feature. Inherent characteristics are easier to achieve in small reactors. However, also in this case, inherent safety does not mean absolute safety. If inherent safety characteristics were all encompassing, they would have to include self-healing effects. However, inanimate matter is incapable of such self-organization. Consequently, inherent characteristics in nuclear technology by definition should include the increased use of dissipative processes in the thermal part of the plant. (author)

  20. HISTORICAL AMERICAN ENGINEERING RECORD - IDAHO NATIONAL ENGINEERING AND ENVIRONMENTAL LABORATORY, TEST AREA NORTH, HAER NO. ID-33-E

    International Nuclear Information System (INIS)

    Susan Stacy; Hollie K. Gilbert

    2005-01-01

    Test Area North (TAN) was a site of the Aircraft Nuclear Propulsion (ANP) Project of the U.S. Air Force and the Atomic Energy Commission. Its Cold War mission was to develop a turbojet bomber propelled by nuclear power. The project was part of an arms race. Test activities took place in five areas at TAN. The Assembly and Maintenance area was a shop and hot cell complex. Nuclear tests ran at the Initial Engine Test area. Low-power test reactors operated at a third cluster. The fourth area was for Administration. A Flight Engine Test facility (hangar) was built to house the anticipated nuclear-powered aircraft. Experiments between 1955-1961 proved that a nuclear reactor could power a jet engine, but President John F. Kennedy canceled the project in March 1961. ANP facilities were adapted for new reactor projects, the most important of which were Loss of Fluid Tests (LOFT), part of an international safety program for commercial power reactors. Other projects included NASA's Systems for Nuclear Auxiliary Power and storage of Three Mile Island meltdown debris. National missions for TAN in reactor research and safety research have expired; demolition of historic TAN buildings is underway

  1. Long term integrity of reactor pressure vessel and primary containment vessel after the severe accidents in Fukushima Daiichi Nuclear Power Station. Leaching property of spent oxide fuel segment and corrosion property of a carbon steel under artificial seawater immersion

    International Nuclear Information System (INIS)

    2014-06-01

    Primary containment vessel (PCV), reactor pressure vessel and pedestal in Fukushima Daiichi Nuclear power station units 1 through 3 have been exposed to severe thermal, chemical and mechanical conditions due to core meltdown events and seawater injections for emergent core cooling. These components will be immersed in diluted seawater with dissolved fission products under irradiation until the end of debris removal. Fresh water injected into the cores contacts with debris to cool, dissolves or erodes their constituents, mixed with retained water, and becomes 'accumulated water' with radioactive nuclides. We have focused the leaching of fission products into the accumulated water under lower temperature (323 K). FUGEN spent oxide fuel segments were immersed to determine the leaching factor of fission product and actinide elements. Since PCV made from carbon steel is one of the most important boundaries to prevent from fission products release, corrosion behavior has been paid attention to evaluate their integrity. Carbon steel specimens were immersion- and electrochemical-tested in diluted seawater with simulants of the accumulated water at 323 K in order to evaluate the effect of fission products in particular cesium and radiation. (author)

  2. Radiation accidents

    International Nuclear Information System (INIS)

    Saenger, E.L.

    1986-01-01

    It is essential that emergency physicians understand ways to manage patients contaminated by radioactive materials and/or exposed to external radiation sources. Contamination accidents require careful surveys to identify the metabolic pathway of the radionuclides to guide prognosis and treatment. The level of treatment required will depend on careful surveys and meticulous decontamination. There is no specific therapy for the acute radiation syndrome. Prophylactic antibodies are desirable. For severely exposed patients treatment is similar to the supportive care given to patients undergoing organ transplantation. For high-dose extremity injury, no methods have been developed to reverse the fibrosing endarteritis that eventually leads to tissue death so frequently found with this type of injury. Although the Three Mile Island episode of March 1979 created tremendous public concern, there were no radiation injuries. The contamination outside the reactor building and the release of radioiodine were negligible. The accidental fuel element meltdown at Chernobyl, USSR, resulted in many cases of acute radiation syndrome. More than 100,000 people were exposed to high levels of radioactive fallout. The general principles outlined here are applicable to accidents of that degree of severity

  3. Outlook of the accident at Fukushima No.1 Nuclear Power Plants and issues concerning radioactive materials in environments

    International Nuclear Information System (INIS)

    Tanaka, Shun-ichi

    2011-01-01

    Fukushima No.1 Nuclear Power Plants (NPPs) affected by a great earthquake finally suffered reactor core meltdown with loss of all cooling capability and discharged a large amount of radioactive materials to the environment. Local areas in the northwest direction from NPPs were highly contaminated with radioactive materials. In order to reduce radiation exposure, several kinds of decontamination works had been tested in contaminated areas of primary school and kindergarten or residential houses with no evacuation. Radiation mini-hotspots were scattered. Contaminated soils and rubbles having cesium of high concentration in the order of several ten or hundreds kBq/kg were accumulated in large amounts of radioactive wastes and their disposal became a big issue. Related safety guidelines were proposed based on radioactive waste disposal for nuclear facilities as well as radiation dose control of neighboring residents and disposal workers, which would not be applicable to current state of Fukushima in a high radiation background. Establishment of new radiation protection rule was highly needed to deal with this emergency based on reality within and outside the Fukushima NPPs. (T. Tanaka)

  4. Release fraction of PWR after severe accidents. Vol. 4

    International Nuclear Information System (INIS)

    Aziz, M.; El-Messeiry, A.M.

    1996-01-01

    Fission fragments and gases are emitted after accidents as a result of core meltdown and core concrete interactions. These aerosols are transported and fill the reactor containment. With increasing the pressure above pressure design bases, a failure of containment may occur and subsequently these aerosols will release into the external environment leading to a source term of radioactivity that affects the safety of workers and public. The amount of aerosol which escapes to the environment can be described by the release fraction which is defined as the total accumulated aerosol which initially enters the containment. The factors that affect the release fraction is studied, and the aerosol dynamics equation is used to model the release of aerosol to the outside atmosphere. These factors are containment pressure, failure time,break area, the size of aerosol particle. It found that early failure time and higher pressure increase the release fraction, also the release faction is affected by the area and the aerosol particle size. 7 figs., 2 tabs

  5. Operational report, basics of the preliminary project for reconstruction of the RA reactor ventilation system

    International Nuclear Information System (INIS)

    Martinc, R.

    1982-01-01

    This report presents the summary of results needed for designing the reconstruction of the RA reactor ventilation system. The final complete report will published later, including results of possible additional analyses according to the needs of main detailed project. Due to the size of the facility the need of filters for particulates is expected in systems V-1 and V-2, as well as revision of the system V-4. Adsorption filters are not needed in case of operation under regular working conditions. It would be favorable, but not indispensable to construct an adsorption filter that could be used occasionally at the input of V-2 system under the upper water shielding. This filter would be switched on when dehermetization of the reactor is planned and increased radioactivity is indicated in the gas system or experimental space of the RA reactor as well as in case of fuel elements failure. The aim of applying filters is shortening the time these elements would spend in the hermetized reactor i.e. their fast removal from the reactor. It is indispensable to build-in 'emergency' highly efficient adsorption filters in the V-2 system which would be switched on in case of accidents that would cause fuel elements meltdown (with simultaneous accident dehermetization of the heavy water system) [sr

  6. Obstacles to the Growth of Alternative Tourism in Greece

    Directory of Open Access Journals (Sweden)

    Athena Smith

    2011-01-01

    Full Text Available In the midst of the recent economic melt-down in Greece, economists are discussing the potential of tourism to pull the country out of its current woes. More than 16 million tourists visit the country annually whereas the sector contributes 15% to the nation's Gross Domestic Product and offers employment to 16% of the work force (Hellenic Statistical Authority, 2010. Concurrently, mass tourism has also caused a rise in pollution, a depletion of water supplies, desertification, rural emigration to urban centers, erosion of coastal areas and a drop in hygienic standards, all of which have had serious economic costs and caused residents to protest the industry’s mode of expansion. To that purpose, alternative types of tourism such as agrotourism and ecotourism have been defined as overarching objectives that complement the strategy for growth and employment. However, a closer look at the spots mostly known for alternative tourism activities shows the parallel emergence of other socio-economic developments that have slowly eroded Greek rural life and intensified the economic disparities between the local social classes. A closer evaluation of the damaging side effects casts doubt on the potential of alternative tourism as practiced today to inject growth into a stagnating economy.

  7. Analyzing Malaysians' perception of risk in developing radiological and nuclear crisis communication framework

    Science.gov (United States)

    Hamid, AHA.; Hassan, H.; Ramanathan, B.; Jumat, AH.; Jaafar, NNH.; Abdullah, A.

    2015-04-01

    Crisis communication is an indicator of a sustaining public normalcy that serves to control and decrease any untoward situations during disasters' meltdown. Prior findings highlighted that 25.85 percent of arising organizational disputes can be resolved using public announcements and an enhancement of public awareness through avoiding related dissatisfactions, disorders and untoward circumstances during radiation and nuclear emergencies. Hence, in this paper, we are interrogating Malaysians on their perception of risk regarding to radiation and nuclear disasters and emergencies. The principal aim is to identify the relationship between the IAEA's initiated risk perception characteristics and the content of the respective public acceptance reports. Those relationships are described and analyzed into a network diagram using the ATLAS.ti software consisting of Clustering and C-Coefficient analyses. This diagram identifies the main variables relating to significant characteristics of risk perception. Future studies should further evaluate the intensity of public opinion against the suggested constructs of executing a thorough and structured risk management mechanism, to advance public trust as well as crisis communication.

  8. Pectin from Citrus Canning Wastewater as Potential Fat Replacer in Ice Cream.

    Science.gov (United States)

    Zhang, Hua; Chen, Jianle; Li, Junhui; Wei, Chaoyang; Ye, Xingqian; Shi, John; Chen, Shiguo

    2018-04-17

    Pectin had been recovered from canning wastewater produced by chemical treatment of segment membrane during preparation of canned citrus in our previous research. The purpose of this study was to characterize the extracted pectin from canning wastewater, and to evaluate its application as a fat alternative to replace fat in ice cream. The monosaccharide composition and rheological properties of the pectin were determined. The influences of fat reduction and pectin addition on the physicochemical, rheological and sensory properties of low-fat ice cream were determined. The rheological results showed that pectin solutions were typical pseudoplastic fluids. The addition of pectin in ice cream can cause an increase in viscosity, overrun, and hardness, and a decrease in meltdown of the ice cream. When 0.72% pectin ( w / w ) is incorporated into ice cream, a prototype product of ice cream with 45% lower fat content compared to the control was made. Results indicated that their qualities such as appearance, flavor, and taste were not significantly different. The low-fat ice cream had higher smoothness scores and lower mouth-coating scores. Hence, pectin extracted from citrus canning wastewater can be potentially used as fat replacer in ice cream, which benefits both the environment and the food industry.

  9. Partisan amplification of risk: American perceptions of nuclear energy risk in the wake of the Fukushima Daiichi disaster

    International Nuclear Information System (INIS)

    Yeo, Sara K.; Cacciatore, Michael A.; Brossard, Dominique; Scheufele, Dietram A.; Runge, Kristin; Su, Leona Y.; Kim, Jiyoun; Xenos, Michael; Corley, Elizabeth A.

    2014-01-01

    Aim: This study examines risk perceptions toward nuclear power before and after the Fukushima Daiichi disaster using nationally representative survey samples of American adults. Scope: On March 11, 2011, a magnitude 8.4 earthquake, the largest in the nation's history, occurred off the coast of Japan. The earthquake produced a devastating tsunami that flooded areas of the Fukushima Daiichi nuclear plant and resulted in a loss of power to the plant's cooling system. In the weeks that followed, the world watched as Japanese and international nuclear power safety experts scrambled to contain the damage and prevent a full meltdown. Although the Fukushima Daiichi disaster was heavily covered in media, there is little empirical research on how this coverage impacted audience risk perceptions. Our analysis goes beyond examining aggregate risk perceptions, instead focusing on how specific sub-populations responded to the disaster. Conclusion: We found that ideological groups responded differently to the events in Japan. In particular, risk perceptions among conservatives decreased following the incident. Moreover, we found that media use exacerbated these effects. We discuss possible explanations for these findings. - Highlights: • We explored American risk perceptions of nuclear energy pre- and post-Fukushima. • Impacts of the disaster endured, likely due to relatively high media coverage. • Conservatives who paid more attention to media perceived less risk post-Fukushima. • Media coverage can serve to polarize opinions instead of mainstreaming them

  10. Economic feeder for recharging and ``topping off''

    Science.gov (United States)

    Fickett, Bryan; Mihalik, G.

    2000-04-01

    Increasing the size of the melt charge significantly increases yield and reduces costs. Siemens Solar Industries is optimizing a method to charge additional material after meltdown (top-off) using an external feeder system. A prototype feeder system was fabricated consisting of a hopper and feed delivery system. The low-cost feeder is designed for simple operation and maintenance. The system is capable of introducing up to 60 kg of granular silicon while under vacuum. An isolation valve permits refilling of the hopper while maintaining vacuum in the growth furnace. Using the feeder system in conjunction with Siemens Solar Industries' energy efficient hot zone dramatically reduces power and argon consumption. Throughput is also improved as faster pull speeds can be attained. The increased pull speeds have an even greater impact when the charge size is increased. Further cost reduction can be achieved by refilling the crucible after crystal growth and pulling a second ingot run. Siemens Solar Industries is presently testing the feeder in production.

  11. Development of compact Compton camera for 3D image reconstruction of radioactive contamination

    Science.gov (United States)

    Sato, Y.; Terasaka, Y.; Ozawa, S.; Nakamura Miyamura, H.; Kaburagi, M.; Tanifuji, Y.; Kawabata, K.; Torii, T.

    2017-11-01

    The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the large tsunami caused by the Great East Japan Earthquake of March 11, 2011. Very large amounts of radionuclides were released from the damaged plant. Radiation distribution measurements inside FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We have developed a compact Compton camera to measure the distribution of radioactive contamination inside the FDNPS buildings three-dimensionally (3D). The total weight of the Compton camera is lower than 1.0 kg. The gamma-ray sensor of the Compton camera employs Ce-doped GAGG (Gd3Al2Ga3O12) scintillators coupled with a multi-pixel photon counter. Angular correction of the detection efficiency of the Compton camera was conducted. Moreover, we developed a 3D back-projection method using the multi-angle data measured with the Compton camera. We successfully observed 3D radiation images resulting from the two 137Cs radioactive sources, and the image of the 9.2 MBq source appeared stronger than that of the 2.7 MBq source.

  12. Laser-heating and Radiance Spectrometry for the Study of Nuclear Materials in Conditions Simulating a Nuclear Power Plant Accident.

    Science.gov (United States)

    Manara, Dario; Soldi, Luca; Mastromarino, Sara; Boboridis, Kostantinos; Robba, Davide; Vlahovic, Luka; Konings, Rudy

    2017-12-14

    Major and severe accidents have occurred three times in nuclear power plants (NPPs), at Three Mile Island (USA, 1979), Chernobyl (former USSR, 1986) and Fukushima (Japan, 2011). Research on the causes, dynamics, and consequences of these mishaps has been performed in a few laboratories worldwide in the last three decades. Common goals of such research activities are: the prevention of these kinds of accidents, both in existing and potential new nuclear power plants; the minimization of their eventual consequences; and ultimately, a full understanding of the real risks connected with NPPs. At the European Commission Joint Research Centre's Institute for Transuranium Elements, a laser-heating and fast radiance spectro-pyrometry facility is used for the laboratory simulation, on a small scale, of NPP core meltdown, the most common type of severe accident (SA) that can occur in a nuclear reactor as a consequence of a failure of the cooling system. This simulation tool permits fast and effective high-temperature measurements on real nuclear materials, such as plutonium and minor actinide-containing fission fuel samples. In this respect, and in its capability to produce large amount of data concerning materials under extreme conditions, the current experimental approach is certainly unique. For current and future concepts of NPP, example results are presented on the melting behavior of some different types of nuclear fuels: uranium-plutonium oxides, carbides, and nitrides. Results on the high-temperature interaction of oxide fuels with containment materials are also briefly shown.

  13. A study of the evaporation of heterogeneous water droplets under active heating

    Science.gov (United States)

    Piskunov, Maxim; Legros, Jean Claude; Strizhak, Pavel

    2016-11-01

    Using high-speed video registration tools with a sample rate of 102-104 frames per second (fps), we studied the patterns in the evaporation of water droplets containing 1 and 2 mm individual metallic inclusions in a high-temperature gas environment. The materials of choice for the inclusions were steels (AISI 1080 carbon steel and AISI type 316L stainless steel) and pure nickel. We established the lifetimes τh of the liquid droplets under study with a controlled increase in the gas environment temperature up to 900 K. We also considered the physical aspects behind the τh distribution in the experiments conducted and specified the conditions for more effective cooling of metallic inclusions. Following the experimental research findings, a method was devised for effective reactor vessel cooling to avoid a meltdown at a nuclear power plant. The optimization of heat and mass transfer modes was performed within the framework of the strategic plan for the development of National Research Tomsk Polytechnic University as one of the world-leading universities.

  14. Establishment of two invasive crustaceans (Copepoda: Harpacticoida) on the nearshore sands of Lake Michigan

    Science.gov (United States)

    Horvath, Thomas G.; Whitman, Richard L.; Last, Laurel L.

    2001-01-01

    Benthic copepods (Copepoda: Harpacticoida) in the nearshore sediments of southern Lake Michigan appear to be dominated by two new invasive species. We report the first occurrence in North America of Schizopera borutzkyi Montschenko, a native to the Danube River delta, and Heteropsyllus nr. nunni, likely a new species that is morphologically similar to the marine species Heteropsyllus nunni and represents the first occurrence of this genus in freshwater. Schizopera borutzkyi is a euryhaline species occurring in shallow sands in its native habitat and in deeper sands (6-15 m) in southern Lake Michigan. Based on the absence of these species from previous studies, we suggest that they are recent introductions. Heteropsyllus nr. nunni dominated (55-100%) the harpacticoid abundance to depths of 9 m, but S. borutzkyi comprised 75% of the harpacticoid abundance at 15 m. Native harpacticoids were always greatly outnumbered by invasive harpacticoids in our samples, which suggests that the natives are being replaced rapidly or that the invasive species are finding unused resources. The ecological implications of these introductions are not known, but these invasions may represent continued 'invasional meltdown' in Lake Michigan.

  15. Fuel Retrieval and Management of Fuel Element Debris

    International Nuclear Information System (INIS)

    Chande, Shridhar; Lachaume, J. L.

    2013-01-01

    Nuclear accidents involving core meltdown have not been so rare. While the first occurred in early fifties, it is reported that about 20 have occurred worldwide in military and commercial reactors. The more recent and major accidents are 1. Three Mile Island, USA in 1979: Approximately half the core was melted, and flowed to the bottom of the reactor pressure vessel however the pressure vessel remained intact and contained the damaged fuel. 2. Chernobyl, former USSR in 1984: Explosive release of radioactive material occurred. About 6 tons of fuel was dispersed as air-borne particles. Most of the core was damaged or melted. 3. Fukushima, Japan 2011: Three units suffered melt down. In unit 1 almost all the fuel assemblies melted and accumulated at the bottom of the vessel. It is reported that the vessel failed and the molten corium has penetrated the concrete. In the units 2 and 3, partial melting of cores has occurred. In several of these cases, fuel retrieval and management activities have been carried out. The experience and insights gained from these activities will be extremely useful for planning and execution of similar activities in future if ever they are needed. The purpose of this session was to exchange this experience and also to share the lessons learned. This is of particularly important, at this juncture, when planning and preparation for retrieval of damaged cores in Fukushima NPP is in progress. (author)

  16. A review of experiments and results from the transient reactor test (TREAT) facility

    International Nuclear Information System (INIS)

    Deitrich, L. W.

    1998-01-01

    The TREAT Facility was designed and built in the late 1950s at Argonne National Laboratory to provide a transient reactor for safety experiments on samples of reactor fuels. It first operated in 1959. Throughout its history, experiments conducted in TREAT have been important in establishing the behavior of a wide variety of reactor fuel elements under conditions predicted to occur in reactor accidents ranging from mild off normal transients to hypothetical core disruptive accidents. For much of its history, TREAT was used primarily to test liquid-metal reactor fuel elements, initially for the Experimental Breeder Reactor-II (EBR-II), then for the Fast Flux Test Facility (FFTF), the Clinch River Breeder Reactor Plant (CRBRP), the British Prototype Fast Reactor (PFR), and finally, for the Integral Fast Reactor (IFR). Both oxide and metal elements were tested in dry capsules and in flowing sodium loops. The data obtained were instrumental in establishing the behavior of the fuel under off-normal and accident conditions, a necessary part of the safety analysis of the various reactors. In addition, TREAT was used to test light-water reactor (LWR) elements in a steam environment to obtain fission-product release data under meltdown conditions. Studies are now under way on applications of TREAT to testing of the behavior of high-burnup LWR elements under reactivity-initiated accident (RIA) conditions using a high-pressure water loop

  17. SIMBATH 1976-1992, seventeen years of experimental investigation of key issues concerned with severe reactor accidents

    International Nuclear Information System (INIS)

    Kaiser, A.; Peppler, W.; Will, H.

    1994-01-01

    The course of the initiating phase of severe fast reactor accidents is determined by early material motion. In simulation experiments (SIMBATH, simulation experiments in fuel element mock-ups with thermite) the behavior of single pin, 7 pin, 19 pin, 37 pin bundles undergoing meltdown was investigated. Thermite (Al + Fe 2 O 3 ) filled tubes were used to simulate fuel rods, while exothermal heat of the thermite reaction simulated the nuclear heat. The energy of 3.4 kJ per centimeter of pin length resulted in melting temperature of about 3200 K. SIMBATH is an out-of-pile experimental program with non-radioactive materials which provided the possibility to perform numerous experiments. The x-ray high speed photography used in the test enabled to visualise material motion and relocation qualitatively, and furthermore to gain quantitative results by additionally installed photodiodes. The results of the experiment serve as a database to evaluate physical phenomena relevant to be modelled by computer codes (SIMMER) and to verify the codes. The experiments were carried out either in stagnant sodium with an axial temperature gradient, or in flowing sodium, simulating unprotected loss of flow (ULOF) or unprotected transient overpower accidents (UTOP) conditions, respectively

  18. Assessment of Mass Fraction and Melting Temperature for the Application of Limestone Concrete and Siliceous Concrete to Nuclear Reactor Basemat Considering Molten Core–Concrete Interaction

    Directory of Open Access Journals (Sweden)

    Hojae Lee

    2016-04-01

    Full Text Available Severe accident scenarios in nuclear reactors, such as nuclear meltdown, reveal that an extremely hot molten core may fall into the nuclear reactor cavity and seriously affect the safety of the nuclear containment vessel due to the chain reaction caused by the reaction between the molten core and concrete. This paper reports on research focused on the type and amount of vapor produced during the reaction between a high-temperature molten core and concrete, as well as on the erosion rate of concrete and the heat transfer characteristics at its vicinity. This study identifies the mass fraction and melting temperature as the most influential properties of concrete necessary for a safety analysis conducted in relation to the thermal interaction between the molten core and the basemat concrete. The types of concrete that are actually used in nuclear reactor cavities were investigated. The H2O content in concrete required for the computation of the relative amount of gases generated by the chemical reaction of the vapor, the quantity of CO2 necessary for computing the cooling speed of the molten core, and the melting temperature of concrete are evaluated experimentally for the molten core–concrete interaction analysis.

  19. Minding the Cyber-Physical Gap: Model-Based Analysis and Mitigation of Systemic Perception-Induced Failure

    Directory of Open Access Journals (Sweden)

    Yaniv Mordecai

    2017-07-01

    Full Text Available The cyber-physical gap (CPG is the difference between the ‘real’ state of the world and the way the system perceives it. This discrepancy often stems from the limitations of sensing and data collection technologies and capabilities, and is inevitable at some degree in any cyber-physical system (CPS. Ignoring or misrepresenting such limitations during system modeling, specification, design, and analysis can potentially result in systemic misconceptions, disrupted functionality and performance, system failure, severe damage, and potential detrimental impacts on the system and its environment. We propose CPG-Aware Modeling & Engineering (CPGAME, a conceptual model-based approach to capturing, explaining, and mitigating the CPG. CPGAME enhances the systems engineer’s ability to cope with CPGs, mitigate them by design, and prevent erroneous decisions and actions. We demonstrate CPGAME by applying it for modeling and analysis of the 1979 Three Miles Island 2 nuclear accident, and show how its meltdown could be mitigated. We use ISO-19450:2015—Object Process Methodology as our conceptual modeling framework.

  20. Results of laboratory tests on a robust filtration system for PWR containments in the case of a serious accident

    International Nuclear Information System (INIS)

    L'Homme, A.; Berlin, M.; Beraud, G.

    1986-01-01

    A study is currently in progress in France on a simple filtration process using sand as a filtration medium which, in the event of a serious accident leading to core meltdown in a pressurized water reactor, will permit controlled and filtered releases from the containment. Laboratory tests on sand filters for aerosols have been conducted. The tests involved the use of columns of sand, 80 cm high and 20 cm in diameter, under conditions which were similar to those inside the containment of a PWR in which a serious accident has occurred. The sand granulometry, the aerosol particle size and the flow rate and steam content of the fluid to be filtered were variable parameters. The results obtained from the experiment showed that as a filtration medium for this simple filter system for reactors a sand obtainable from the Cattenom quarry was most suitable. For this sand the filtration coefficient for aerosols is greater than 10 and the pressure drop is less than 10 4 pascals. Experience has also shown that there is no risk, under the operating conditions envisaged, that the filter will become clogged by aerosols or steam from condensed water or that there will be any major escape of aerosols retained during long-term operation of the filter or caused by the vaporisation of the condensed water. A larger scale experiment is already being carried out. (author)

  1. What happened at Fukushima Daiichi Nuclear Power Plants. Verification of effects of earthquake and resulting tsunami

    International Nuclear Information System (INIS)

    Yamazaki, Tatsuhiro

    2012-01-01

    At 14:46 on March 11, 2011, the Tohoku District-off the Pacific Ocean Earthquake occurred. The magnitude of this earthquake was 9.0, the largest in Japan's recorded history, and afterwards enormous tsunami struck the Pacific coast of Tohoku District. This great earthquake and resulting tsunami struck the Fukushima Daiichi Nuclear Power Plants (NPPs) of Tokyo Electric Power Co. (TEPCO), whose cooling function was lost and suffered a severe nuclear accident. This article described the mechanism and safety measure of BWR type NPPs and verified how the great earthquake and resulting tsunami affected NPPs. Progression of the accident at Fukushima Daiichi NPPs was outlined. Damage by the earthquake could not be fully inspected but might not be significant to safety systems. However, the earthquake of longer duration time as much as about 250 sec caused failure of breaker or lightening arrester and also damage on electric facility such as transmission line insulator. Tsunami or inundation height was as high as O.P. (Onahama Pile) +11.5-15.5 m for Unit 1-4 reactor area while designed as O.P. +5.7 m, which caused blackout (power outage) and a reactor core meltdown at Fukushima Daiichi NPPs. (T. Tanaka)

  2. Advice about the safety aspects of the fuel cycle in the Netherlands

    International Nuclear Information System (INIS)

    1975-09-01

    The Commissie Reactorveiligheid has carried out a study to investigate the rate of release in radioactivity if the installed nuclear power is increased to 35000 MW(e) with BWR and PWR type reactors. A description is given of the structure, organization and responsibilities of the several authorities concerned with the legal aspects, licensing procedures, reactor commissioning and inspection. A description is given of each stage of the fuel cycle as located in the Netherlands. The possibility of released radioactivity is summarized, and guidelines to prevent, minimize or regulate the release of radioactivity are presented. Special attention is given to the nuclear power plant itself, where external effects with regard to the possible release of radioactivity are discussed, such as flooding, sabotage, earthquakes, aircraft collisions, chemical explosions, hurricanes and accidents which can occur during operation of the power plant, or design-basis accidents within the reactor core or inside the reactor building, such as core meltdown, cooling pipe rupture, containment rupture, spent fuel element pool, containers with fuel elements and radioactive waste tanks. Guidelines are given for the physical protection of the nuclear power plant, transport of nuclear materials, and administration of nuclear materials

  3. Toward a Mechanistic Source Term in Advanced Reactors: A Review of Past U.S. SFR Incidents, Experiments, and Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bucknor, Matthew; Brunett, Acacia J.; Grabaskas, David

    2016-04-17

    In 2015, as part of a Regulatory Technology Development Plan (RTDP) effort for sodium-cooled fast reactors (SFRs), Argonne National Laboratory investigated the current state of knowledge of source term development for a metal-fueled, pool-type SFR. This paper provides a summary of past domestic metal-fueled SFR incidents and experiments and highlights information relevant to source term estimations that were gathered as part of the RTDP effort. The incidents described in this paper include fuel pin failures at the Sodium Reactor Experiment (SRE) facility in July of 1959, the Fermi I meltdown that occurred in October of 1966, and the repeated melting of a fuel element within an experimental capsule at the Experimental Breeder Reactor II (EBR-II) from November 1967 to May 1968. The experiments described in this paper include the Run-Beyond-Cladding-Breach tests that were performed at EBR-II in 1985 and a series of severe transient overpower tests conducted at the Transient Reactor Test Facility (TREAT) in the mid-1980s.

  4. On Numerical Methods in Non-Newtonian Flows

    International Nuclear Information System (INIS)

    Fileas, G.

    1982-12-01

    The constitutive equations for non-Newtonian flows are presented and the various flow models derived from continuum mechanics and molecular theories are considered and evaluated. Detailed account is given of numerical simulation employing differential and integral models of different kinds of non-Newtonian flows using finite-difference and finite-element techniques. Appreciating the fact that no book or concentrated material on Numerical Non-Newtonian Fluid Flow exists at the present, procedures for computer set-ups are described and references are given for finite-difference, finite-element and molecular-theory based programmes for several kinds of flow. Achievements and unreached goals in the field of numerical simulation of non-Newtonian flows are discussed and the lack of numerical work in the fields of suspension flows and heat transfer is pointed out. Finally, FFOCUS is presented as a newly built computer program which can simulate freezing flows on Newtonian fluids through various geometries and is aimed to be further developed to handle non-Newtonian freezing flows and certain types of suspension phenomena involved in corium flow after a hypothetical core melt-down accident in a PWR. (author)

  5. “Wer jetzt kein Haus hat, baut sich keines mehr”. Notes on Bruce O’Neill’s "The Space of Boredom"

    Directory of Open Access Journals (Sweden)

    George Tudorie

    2017-12-01

    Full Text Available Bruce O’Neill describes homeless men and women in Bucharest who could not navigate the downward spiral which followed the meltdown of the state-run economy after 1989. Deprived of the culturally treasured anchors of work, home, and family, and unable to participate in anything recognizably meaningful, these individuals are forced into a position of malignant contemplation, even when busy surviving. It is an experience of paralyzed restlessness which resonates with the ruins they zigzag through. The Space of Boredom captures this landscape convincingly, and in elegant prose. The book moves effortlessly from the discussion of scholarly works in a number of fields, to observation of sometimes cinematic quality. It is well argued, abundantly researched, and clear about its theoretical assumptions. If some questions remain to be answered, at least to this reader, this may be an artifact of background. Assumptions, including important ones about the nature of affects, and about boredom itself, may not be shared. Some questions of this kind will be raised in the following.

  6. Web-based automation of green building rating index and life cycle cost analysis

    Science.gov (United States)

    Shahzaib Khan, Jam; Zakaria, Rozana; Aminuddin, Eeydzah; IzieAdiana Abidin, Nur; Sahamir, Shaza Rina; Ahmad, Rosli; Nafis Abas, Darul

    2018-04-01

    Sudden decline in financial markets and economic meltdown has slow down adaptation and lowered interest of investors towards green certified buildings due to their higher initial costs. Similarly, it is essential to fetch investor’s attention towards more development of green buildings through automated tools for the construction projects. Though, historical dearth is found on the automation of green building rating tools that brings up an essential gap to develop an automated analog computerized programming tool. This paper present a proposed research aim to develop an integrated web-based automated analog computerized programming that applies green building rating assessment tool, green technology and life cycle cost analysis. It also emphasizes to identify variables of MyCrest and LCC to be integrated and developed in a framework then transformed into automated analog computerized programming. A mix methodology of qualitative and quantitative survey and its development portray the planned to carry MyCrest-LCC integration to an automated level. In this study, the preliminary literature review enriches better understanding of Green Building Rating Tools (GBRT) integration to LCC. The outcome of this research is a pave way for future researchers to integrate other efficient tool and parameters that contributes towards green buildings and future agendas.

  7. Nuclear Safeguards Infrastructure Required for the Next Generation Nuclear Plant (NGNP)

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Mark Schanfein; Philip Casey Durst

    2012-07-01

    The Next Generation Nuclear Plant (NGNP) is a Very High Temperature Gas-Cooled Reactor (VHTR) to be constructed near Idaho Falls, Idaho The NGNP is intrinsically safer than current reactors and is planned for startup ca. 2021 Safety is more prominent in the minds of the Public and Governing Officials following the nuclear reactor meltdown accidents in Fukushima, Japan The authors propose that the NGNP should be designed with International (IAEA) Safeguards in mind to support export to Non-Nuclear-Weapons States There are two variants of the NGNP design; one using integral Prismatic-shaped fuel assemblies in a fixed core; and one using recirculating fuel balls (or Pebbles) The following presents the infrastructure required to safeguard the NGNP This infrastructure is required to safeguard the Prismatic and Pebble-fueled NGNP (and other HTGR/VHTR) The infrastructure is based on current Safeguards Requirements and Practices implemented by the International Atomic Energy Agency (IAEA) for similar reactors The authors of this presentation have worked for decades in the area of International Nuclear Safeguards and are recognized experts in this field Presentation for INMM conference in July 2012.

  8. Long-range dependence in returns and volatility of global gold market amid financial crises

    Science.gov (United States)

    Omane-Adjepong, Maurice; Boako, Gideon

    2017-04-01

    Using sampled historical daily gold market data from 07-03-1985 to 06-01-2015, and building on a related work by Bentes (2016), this paper examines the presence of long-range dependence (LRD) in the world's gold market returns and volatility, accounting for structural breaks. The sampled gold market data was divided into subsamples based on four global crises: the September 1992 collapse of the European Exchange Rate Mechanism (ERM), the Asian financial crisis of mid-1997, the Subprime meltdown of 2007, and the recent European sovereign debt crisis, which hit the world's market with varying effects. LRD test was carried-out on the full-sample and subsample periods using three semiparametric methods-before and after adjusting for structural breaks. The results show insignificant evidence of LRD in gold returns. However, very diminutive evidence is found for periods characterized by financial/economic shocks, with no significant detections for post-shock periods. Collectively, this is indicative that the gold market is less speculative, and hence could be somehow less risky for hedging and portfolio diversification.

  9. Infrared Thermal Signature Evaluation of a Pure and Saline Ice for Marine Operations in Cold Climate

    Directory of Open Access Journals (Sweden)

    Taimur Rashid

    2015-11-01

    Full Text Available Marine operations in cold climates are subjected to abundant ice accretion, which can lead to heavy ice loads over larger surface area. For safe and adequate operations on marine vessels over a larger area, remote ice detection and ice mitigation system can be useful. To study this remote ice detection option, lab experimentation was performed to detect the thermal gradient of ice with the infrared camera. Two different samples of ice blocks were prepared from tap water and saline water collected from the North Atlantic Ocean stream. The surfaces of ice samples were observed at room temperature. A complete thermal signature over the surface area was detected and recorded until the meltdown process was completed. Different temperature profiles for saline and pure ice samples were observed, which were kept under similar conditions. This article is focused to understand the experimentation methodology and thermal signatures of samples. However, challenges remains in terms of the validation of the detection signature and elimination of false detection.

  10. Risk management.

    Science.gov (United States)

    Chambers, David W

    2010-01-01

    Every plan contains risk. To proceed without planning some means of managing that risk is to court failure. The basic logic of risk is explained. It consists in identifying a threshold where some corrective action is necessary, the probability of exceeding that threshold, and the attendant cost should the undesired outcome occur. This is the probable cost of failure. Various risk categories in dentistry are identified, including lack of liquidity; poor quality; equipment or procedure failures; employee slips; competitive environments; new regulations; unreliable suppliers, partners, and patients; and threats to one's reputation. It is prudent to make investments in risk management to the extent that the cost of managing the risk is less than the probable loss due to risk failure and when risk management strategies can be matched to type of risk. Four risk management strategies are discussed: insurance, reducing the probability of failure, reducing the costs of failure, and learning. A risk management accounting of the financial meltdown of October 2008 is provided.

  11. Alternate approaches to nuclear safety

    International Nuclear Information System (INIS)

    Crane, A.T.

    1985-01-01

    For the US nuclear power industry to expand, a greatly increased portion of the public must come to share the industry's confidence in reactor safety. Major obstacles to establishing this confidence are frequent incidents with potential safety implications and a lack of incontrovertible proof that the risk of a major accident is very low. The most important step toward overcoming these obstacles would be for each utility to operate, maintain, and evaluate its reactors according to far higher standards. With improvements in reliability and safety margins, existing plants would be a stimulus for building new ones rather than an impediment. If changes to the operation of existing plants and improvements to the design of future ones were inadequate, the only hope for a revival of the nuclear industry would be an alternative reactor so obviously safe that risk would no longer be an issue. Three possible concepts are the modular high-temperature gas reactor, the process inherent ultimate safety reactor, and the liquid-metal fast reactor. All three have inherent safety features that should make a meltdown essentially impossible. They cannot know just how great the advantage of these alternate reactors would be, but the benefits of developing one or more of the concepts appear great

  12. Taking the moral hazard out of banking: the next fundamental step in financial reform

    Directory of Open Access Journals (Sweden)

    Rainer Masera

    2011-01-01

    Full Text Available The path between financial meltdown and moral hazard in banking is, at best, narrow and impervious. During the financial crisis, public support became the standard response to save the banks in difficulty, heightening and broadening the moral hazard issue: subordinated/senior debt holders and large depositors were bailed out and equity holders were partially sheltered. In the Eurozone, the implicit promise to bail-out governments in difficulty has encouraged SIFIs and other financial operators to speculate on the yield differential between sovereigns and the ECB money market interest rates. The policy framework proposed here is two-pronged: the EFSF should evolve to permit more flexible and wide-ranging interventions, and be able to manage sovereign debt restructuring; with respect to SIFIs, very early corporate, market and supervisory responses are suggested. Intervention of supervisory authorities with mandatory (special powers would occur before the threshold of non-viability and, on a gone-concern basis, in terms of a European resolution procedure.

  13. Impacts modeling using the SPH particulate method. Case study; Modelisation d'impacts par la methode particulaire SPH. Etude de cas

    Energy Technology Data Exchange (ETDEWEB)

    Debord, R

    1999-07-01

    The aim of this study is the modeling of the impact of melted metal on the reactor vessel head in the case of a core-meltdown accident. Modeling using the classical finite-element method alone is not sufficient but requires a coupling with particulate methods in order to take into account the behaviour of the corium. After a general introduction about particulate methods, the Nabor and SPH (smoothed particle hydrodynamics) methods are described. Then, the theoretical and numerical reliability of the SPH method is determined using simple cases. In particular, the number of neighbours significantly influences the preciseness of calculations. Also, the mesh of the structure must be adapted to the mesh of the fluid in order to reduce the edge effects. Finally, this study has shown that the values of artificial velocity coefficients used in the simulation of the BERDA test performed by the FZK Karlsruhe (Germany) are not correct. The domain of use of these coefficients was precised during a low speed impact. (J.S.)

  14. Reflections on the value concept in accounting

    Directory of Open Access Journals (Sweden)

    P. Buys

    2009-07-01

    Full Text Available The recent meltdown in global finances and the reasons for it may make people doubtful about the stewardship function of accounting. In the global financial markets, there is a great fascination with the reality that accounting values intend to reflect. However, what many people considered valuable is now suddenly of no value. The question can therefore be asked what is meant by the value concept as a foundation to modern-day accountancy. “Value” is a concept that is open to different interpretations, based on the needs, perspectives and personal values of the interpreter. This article aims to reflect on the value concept from an accounting perspective in analysing the fundamental quali-tative perspectives and how these perspectives might affect the quantitative value measurements, as reported in the financial statements. From a quantitative perspective, accounttancy aims to measure and report the monetary values of items. However, there is a move towards a mixed valuation model with many financial statements, including both historical cost and value-based accounting information. The article concludes that this questionable development opens up many additional and subjective interpretations of accounting value measurement and reporting. Both valuation measurement methods have merit when considered in the overall purpose of accounting information. However, subjective value-based mea-surements may cast a shadow of doubt on the reliability and comparability requirements of accounting value information.

  15. Tracking of a Fluorescent Dye in a Freshwater Lake with an Unmanned Surface Vehicle and an Unmanned Aircraft System

    Directory of Open Access Journals (Sweden)

    Craig Powers

    2018-01-01

    Full Text Available Recent catastrophic events in our oceans, including the spill of toxic oil from the explosion of the Deepwater Horizon drilling rig and the rapid dispersion of radioactive particulates from the meltdown of the Fukushima Daiichi nuclear plant, underscore the need for new tools and technologies to rapidly respond to hazardous agents. Our understanding of the movement and aerosolization of hazardous agents from natural aquatic systems can be expanded upon and used in prevention and tracking. New technologies with coordinated unmanned robotic systems could lead to faster identification and mitigation of hazardous agents in lakes, rivers, and oceans. In this study, we released a fluorescent dye (fluorescein into a freshwater lake from an anchored floating platform. A fluorometer (fluorescence sensor was mounted underneath an unmanned surface vehicle (USV, unmanned boat and was used to detect and track the released dye in situ in real-time. An unmanned aircraft system (UAS was used to visualize the dye and direct the USV to sample different areas of the dye plume. Image processing tools were used to map concentration profiles of the dye plume from aerial images acquired from the UAS, and these were associated with concentration measurements collected from the sensors onboard the USV. The results of this project have the potential to transform monitoring strategies for hazardous agents, enabling timely and accurate exposure assessment and response in affected areas. Fast response is essential in reacting to the introduction of hazardous agents, in order to quickly predict and contain their spread.

  16. Inhibition between invasives: a newly introduced predator moderates the impacts of a previously established invasive predator.

    Science.gov (United States)

    Griffen, Blaine D; Guy, Travis; Buck, Julia C

    2008-01-01

    1. With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. Interactions between invasive species may provide important mechanisms that moderate their impacts on native species. 2. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid-1800 s and is capable of rapid consumption of bivalve prey. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions as C. maenas within the Gulf of Maine. Using a series of field and laboratory investigations, we examined the consequences of interactions between these predators. 3. Density patterns of these two species at different spatial scales are consistent with negative interactions. As a result of these interactions, C. maenas alters its diet to consume fewer mussels, its preferred prey, in the presence of H. sanguineus. Decreased mussel consumption in turn leads to lower growth rates for C. maenas, with potential detrimental effects on C. maenas populations. 4. Rather than an invasional meltdown, this study demonstrates that, within the Gulf of Maine, this new invasive predator can moderate the impacts of the older invasive predator.

  17. Somatic mutation analysis of MYH11 in breast and prostate cancer

    International Nuclear Information System (INIS)

    Alhopuro, Pia; Karhu, Auli; Winqvist, Robert; Waltering, Kati; Visakorpi, Tapio; Aaltonen, Lauri A

    2008-01-01

    MYH11 (also known as SMMHC) encodes the smooth-muscle myosin heavy chain, which has a key role in smooth muscle contraction. Inversion at the MYH11 locus is one of the most frequent chromosomal aberrations found in acute myeloid leukemia. We have previously shown that MYH11 mutations occur in human colorectal cancer, and may also be associated with Peutz-Jeghers syndrome. The mutations found in human intestinal neoplasia result in unregulated proteins with constitutive motor activity, similar to the mutant myh11 underlying the zebrafish meltdown phenotype characterized by disrupted intestinal architecture. Recently, MYH1 and MYH9 have been identified as candidate breast cancer genes in a systematic analysis of the breast cancer genome. The aim of this study was to investigate the role of somatic MYH11 mutations in two common tumor types; breast and prostate cancers. A total of 155 breast cancer and 71 prostate cancer samples were analyzed for those regions in MYH11 (altogether 8 exons out of 42 coding exons) that harboured mutations in colorectal cancer in our previous study. In breast cancer samples only germline alterations were observed. One prostate cancer sample harbored a frameshift mutation c.5798delC, which we have previously shown to result in a protein with unregulated motor activity. Little evidence for a role of somatic MYH11 mutations in the formation of breast or prostate cancers was obtained in this study

  18. Analyzing Malaysians’ perception of risk in developing radiological and nuclear crisis communication framework

    Energy Technology Data Exchange (ETDEWEB)

    Hamid, AHA., E-mail: amyhamijah@nm.gov.my [Malaysian Nuclear Agency (NM), Bangi, 43000 Kajang, Selangor (Malaysia); Faculty of Computing, Universiti Teknologi Malaysia (UTM), Skudai, 81310 Johor Bahru, Johor (Malaysia); Hassan, H., E-mail: asfa@nm.gov.my; Ramanathan, B.; Jumat, AH. [Malaysian Nuclear Agency (NM), Bangi, 43000 Kajang, Selangor (Malaysia); Jaafar, NNH.; Abdullah, A. [Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bandar Baru Bangi 43650, Kajang, Selangor (Malaysia)

    2015-04-29

    Crisis communication is an indicator of a sustaining public normalcy that serves to control and decrease any untoward situations during disasters’ meltdown. Prior findings highlighted that 25.85 percent of arising organizational disputes can be resolved using public announcements and an enhancement of public awareness through avoiding related dissatisfactions, disorders and untoward circumstances during radiation and nuclear emergencies. Hence, in this paper, we are interrogating Malaysians on their perception of risk regarding to radiation and nuclear disasters and emergencies. The principal aim is to identify the relationship between the IAEA’s initiated risk perception characteristics and the content of the respective public acceptance reports. Those relationships are described and analyzed into a network diagram using the ATLAS.ti software consisting of Clustering and C-Coefficient analyses. This diagram identifies the main variables relating to significant characteristics of risk perception. Future studies should further evaluate the intensity of public opinion against the suggested constructs of executing a thorough and structured risk management mechanism, to advance public trust as well as crisis communication.

  19. Reactor safety research against the backdrop of the Energy-Omnibus Law

    International Nuclear Information System (INIS)

    Kuczera, B.

    1995-01-01

    On July 19, 1994, the German Federal Parliament adopted the Coal/Nuclear Power Omnibus Law, in which a new quality of safety of future nuclear power plants has been laid down. The defense-in-depth safety concept underlying the nuclear power plants currently in operation is derived from the principle of safety precautions made against reactor accidents, and encompasses preventive measures of accident mangement and mitigating measures of containing possible consequences. Accident management leads to the requirement that even in the most unlikely accidents with core meltdown the consequences remain limited to the plant. A new quality in reactor safety is represented by the System 80+ advanced pressurized water reactor and by the European Pressurized Water Reactor, EPR. Despite different views about the approaches used to address individaul aspects in the achievement of safety goals, there is agreement on the principle that risk provisions, by achieving more transparency, are to result in better public acceptance of the peaceful uses of nuclear power. (orig.) [de

  20. Core failure accident pathways and ways to control it

    International Nuclear Information System (INIS)

    Mayinger, F.

    1982-01-01

    In the German Risk Study accidents are assumed to result in core meltdown whenever the criteria spelt out in the guidelines of the Advisory Committee on Reactor Safeguards are no longer met. This assumption must be seen in the light of an earlier state of the art in which no detailed information could be obtained about intermediate stages in emergency core cooling systems working according to permit up to the complete failure of all heat removal systems. However, experimental studies and theoretical analyses conducted over the past few years have advanced the state of the art such that it is now possible to predict with considerably more physical reality the behavior of a core in a loss-of-coolant accident. These findings are not only based on calculations, but also on the results of experiments in large facilities allowing direct comparisons to be made with conditions in nuclear power plants. Studies of the effects of systems failures both in major leakages and in the small leakages regarded to be much more dangerous show much more favorable conditions with respect to core coolability than had to be anticipated on the basis of earlier assumptions. This also implies that it would neither be necessary nor meaningful to reinforce emergency core cooling systems. Instead, it is much more important, besides having technically highly qualified and thoroughly trained operating crews, to inform those crews reliably of the hydrodynamic and thermodynamic state of the primary system, especially the core. (orig.) [de

  1. The German nuclear power plant safety study

    International Nuclear Information System (INIS)

    1979-01-01

    With this study a new approach has been chosen, taking nuclear power plants as an example to assess and to describe the risks arising from the use of modern technology, including those hazards emanating from the rather hypothetical possibility of occurrence of very serious accidents. Following the definition of basic concepts and methods to be applied in risk assessment studied, as well as a brief account of the design and operating mode of nuclear power plants with PWRs', accidents and failures to be considered in a safety study are described. Using the course-of-event and fault tree analysis, the probability of fission product release as a consequence of failures in safety systems or of core meltdown is evaluated. Subsequently, the theoretical model for assessment of reactor accident consequences is presented, discussing such aspects as the dispersion of radioactivity in the atmosphere, the radiation dose model, safety and countermeasures, the model for the evaluation of health hazards as well as methods and calculations for estimating the reliability of risk assessments together with the remaining uncertainties. In an appendix to this study, the analyses presented in the study are discussed in the light of the TMI-2 event. This safety study showing the possibilities of detecting, keeping in check and minimizing harmful effects, can be regarded as a contribution to a better understanding of our modern, highly industrialised society, and eventually to an improvement of the quality of life. (GL) 891 GL/GL 892 MB [de

  2. KAPOOL experiments to simulate molten corium - sacrificial concrete interaction

    International Nuclear Information System (INIS)

    Eppinger, B.; Fieg, G.; Tromm, W.

    2001-01-01

    In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. In the planned European Pressurized Reactor (EPR) the core melt is retained in the reactor cavity for ∼ 1 h to pick up late melts after the failure of the reactor pressure vessel. The reactor cavity is protected by a layer of sacrificial concrete and closed by a melt gate at the bottom towards the spreading compartment. After erosion of the sacrificial concrete and melt-through of the gate the core melt should be distributed homogeneously into the spreading compartment. There the melt is cooled by flooding with water. The knowledge of the sacrificial concrete erosion phase in the reactor cavity is essential for the severe accident assessment. Several KAPOOL experiments have been performed to investigate the erosion of two possible compositions of sacrificial concretes using alumina-iron thermite melts as a simulant for the core melt. Erosion rates as a function of the melt temperature and the inhomogeneity of the melt front are presented in this paper. (authors)

  3. Acoustic detection of melt particles

    International Nuclear Information System (INIS)

    Costley, R.D. Jr.

    1988-01-01

    The Reactor Safety Research Department at Sandia National Laboratories is investigating a type of Loss of Coolant Accident (LOCA). In this particular type of accident, core meltdown occurs while the pressure within the reactor pressure vessel (RPV) is high. If one of the instrument tube penetrations in the lower head fails, melt particles stream through the cavity and into the containment vessel. This experiment, which simulates this type accident, was performed in the Surtsev Direct Heating Test Facility which is approximately a 1:10 linear scaling of a large dry containment volume. A 1:10 linear scale model of the reactor cavity was placed near the bottom of the Surtsey vessel so that the exit of the cavity was at the vertical centerline of the vessel. A pressure vessel used to create the simulated molten core debris was located at the scaled height of the RPV. In order to better understand how the melt leaves the cavity and streams into the containment an array of five acoustic sensors was placed directly in the path of the melt particles about 30 feet from the exit of the sealed cavity. Highly damped, broadband sensors were chosen to minimize ringing so that individual particle hits could be detected. The goal was to count the signals produced by the individual particle hits to get some idea of how the melt particles left the cavity. This document presents some of the results of the experiment. 9 figs

  4. Exploratory study of molten core material/concrete interactions, July 1975--March 1977

    International Nuclear Information System (INIS)

    Powers, D.A.; Dahlgren, D.A.; Muir, J.F.; Murfin, W.D.

    1978-02-01

    An experimental study of the interaction between high-temperature molten materials and structural concrete is described. The experimental efforts focused on the interaction of melts of reactor core materials weighing 12 to 200 kg at temperatures 1700 to 2800 0 C with calcareous and basaltic concrete representative of that found in existing light-water nuclear reactors. Observations concerning the rate and mode of melt penetration into concrete, the nature and generation rate of gases liberated during the interaction, and heat transfer from the melt to the concrete are described. Concrete erosion is shown to be primarily a melting process with little contribution from mechanical spallation. Water and carbon dioxide thermally released from the concrete are extensively reduced to hydrogen and carbon monoxide. Heat transfer from the melt to the concrete is shown to be dependent on gas generation rate and crucible geometry. Interpretation of results from the interaction experiments is supported by separate studies of the thermal decomposition of concretes, response of bulk concrete to intense heat fluxes (28 to 280 W/cm 2 ), and heat transfer from molten materials to decomposing solids. The experimental results are compared to assumptions made in previous analytic studies of core meltdown accidents in light-water nuclear reactors. A preliminary computer code, INTER, which models and extrapolates results of the experimental program is described. The code allows estimation of the effect of physical parameters on the nature of the melt/concrete interaction

  5. Review of the current understanding of the potential for containment failure from in-vessel steam explosions

    International Nuclear Information System (INIS)

    1985-06-01

    A group of experts was convened to review the current understanding of the potential for containment failure from in-vessel steam explosions during core meltdown accidents in LWRs. The Steam Explosion Review Group (SERG) was requested to provide assessments of: (1) the conditional probability of containment failure due to a steam explosion, (2) a Sandia National Laboratory (SNL) report entitled ''An Uncertainty Study of PWR Steam Explosions,'' NUREG/CR-3369, (3) a SNL proposed steam explosion research program. This report summarizes the results of the deliberations of the review group. It also presents the detailed response of each individual member to each of the issues. The consensus of the SERG is that the occurrence of a steam explosion of sufficient energetics which could lead to alpha-mode containment failure has a low probability. The SERG members disagreed with the methodology used in NUREG/CR-3369 for the purpose of establishing the uncertainty in the probability of containment failure by a steam explosion. A consensus was reached among SERG members on the need for a continuing steam explosion research program which would improve our understanding of certain aspects of steam explosion phenomenology

  6. Heat transfer between immiscible liquids enhanced by gas bubbling

    International Nuclear Information System (INIS)

    Greene, G.A.; Schwarz, C.E.; Klages, J.; Klein, J.

    1982-08-01

    The phenomena of core-concrete interactions impact upon containment integrity of light water reactors (LWR) following postulated complete meltdown of the core by containment pressurization, production of combustible gases, and basemat penetration. Experiments have been performed with non-reactor materials to investigate one aspect of this problem, heat transfer between overlying immiscible liquids whose interface is disturbed by a transverse non-condensable gas flux emanating from below. Hydrodynamic studies have been performed to test a criterion for onset of entrainment due to bubbling through the interface and subsequent heat transfer studies were performed to assess the effect of bubbling on interfacial heat transfer rates, both with and without bubble induced entrainment. Non-entraining interfacial heat transfer data with mercury-water/oil fluid pairs were observed to be bounded from below within a factor of two to three by the Szekeley surface renewal heat transfer model. However heat transfer data for fluid pairs which are found to entrain (water-oil), believed to be characteristic of molten reactor core-concrete conditions, were measured to be up to two orders of magnitude greater than surface renewal predictions and are calculated by a simple entrainment heat transfer model

  7. Nuclear security and challenges at nuclear power plants. Part 1. Basis of nuclear security

    International Nuclear Information System (INIS)

    Demachi, Kazuyuki

    2017-01-01

    The tsunami that occurred in March 2011 associated with the 2011 off the Pacific coast of Tohoku Earthquake hit TEPCO Fukushima Daiichi Nuclear Power Station (1F). The 1F got into station blackout situation, and fell into reactor core meltdown due to inability of cooling down the reactor, eventually leading to the emission accident of radioactive substances over a wide range into the atmosphere, soil, seawater and the like. Through various media such as newspapers, TVs, and the Internet after the accident, important facilities for safety were explained with illustrations. Some of them included the contents that can suggest the causes that trigger the same accident as the 1F accident. It is an urgent task to strengthen security against the terrorism aimed at nuclear power facilities including nuclear power plants, and its realization is a serious problem in each country. This paper summarized nuclear security issues and solutions including explanation on the circumstances of the threat increase of nuclear terrorism that had begun before the 1F accident. The recent nuclear security summit reaffirmed that nuclear security is the basic responsibility of each country, and also reaffirmed the responsibility and importance of IAEA for international cooperation. This paper explains the definition of nuclear security, threat of terrorism, and the contents of the IAEA Nuclear Security Series (NSS), and points out that NSS is considered as the basis among basis that all the countries should share. (A.O.)

  8. Prediction of LOCA Break Size Using CFNN

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Geon Pil; Yoo, Kwae Hwan; Back, Ju Hyun; Kim, Dong Yeong; Na, Man Gyun [Chosun University Gwangju (Korea, Republic of)

    2016-05-15

    The NPPs have the emergency core cooling system (ECCS) such as a safety injection system. The ECCS may not function properly in case of the small break size due to a slight change of pressure in the pipe. If the coolant is not supplied by ECCS, the reactor core will melt. Therefore, the meltdown of reactor core have to be prevented by appropriate accident management through the prediction of LOCA break size in advance. This study presents the prediction of LOCA break size using cascaded fuzzy neural network (CFNN). The CFNN model repeatedly applies FNN modules that are serially connected. The CFNN model is a data-based method that requires data for its development and verification. The data were obtained by numerically simulating severe accident scenarios of the optimized power reactor (OPR1000) using MAAP code, because real severe accident data cannot be obtained from actual NPP accidents. The CFNN model has been designed to rapidly predict the LOCA break size in LOCA situations. The CFNN model was trained by using the training data set and checked by using test data set. These data sets were obtained using MAAP code for OPR1000 reactor. The performance results of the CFNN model show that the RMS error decreases as the stage number of the CFNN model increases. In addition, the performance result of the CFNN model presents that the RMS error level is below 4%.

  9. Understanding the nature of nuclear power plant risk

    International Nuclear Information System (INIS)

    Denning, R. S.

    2012-01-01

    This paper describes the evolution of understanding of severe accident consequences from the non-mechanistic assumptions of WASH-740 to WASH-1400, NUREG-1150, SOARCA and today in the interpretation of the consequences of the accident at Fukushima. As opposed to the general perception, the radiological human health consequences to members of the Japanese public from the Fukushima accident will be small despite meltdowns at three reactors and loss of containment integrity. In contrast, the radiation-related societal impacts present a substantial additional economic burden on top of the monumental task of economic recovery from the nonnuclear aspects of the earthquake and tsunami damage. The Fukushima accident provides additional evidence that we have mis-characterized the risk of nuclear power plant accidents to ourselves and to the public. The human health risks are extremely small even to people living next door to a nuclear power plant. The principal risk associated with a nuclear power plant accident involves societal impacts: relocation of people, loss of land use, loss of contaminated products, decontamination costs and the need for replacement power. Although two of the three probabilistic safety goals of the NRC address societal risk, the associated quantitative health objectives in reality only address individual human health risk. This paper describes the types of analysis that would address compliance with the societal goals. (authors)

  10. Cost benefit analysis of reactor safety systems

    International Nuclear Information System (INIS)

    Maurer, H.A.

    1984-01-01

    Cost/benefit analysis of reactor safety systems is a possibility appropriate to deal with reactor safety. The Commission of the European Communities supported a study on the cost-benefit or cost effectiveness of safety systems installed in modern PWR nuclear power plants. The following systems and their cooperation in emergency cases were in particular investigated in this study: the containment system (double containment), the leakage exhaust and control system, the annulus release exhaust system and the containment spray system. The benefit of a safety system is defined according to its contribution to the reduction of the radiological consequences for the environment after a LOCA. The analysis is so far performed in two different steps: the emergency core cooling system is considered to function properly, failure of the emergency core cooling system is assumed (with the possible consequence of core melt-down) and the results may demonstrate the evidence that striving for cost-effectiveness can produce a safer end result than the philosophy of safety at any cost. (orig.)

  11. Pectin from Citrus Canning Wastewater as Potential Fat Replacer in Ice Cream

    Directory of Open Access Journals (Sweden)

    Hua Zhang

    2018-04-01

    Full Text Available Pectin had been recovered from canning wastewater produced by chemical treatment of segment membrane during preparation of canned citrus in our previous research. The purpose of this study was to characterize the extracted pectin from canning wastewater, and to evaluate its application as a fat alternative to replace fat in ice cream. The monosaccharide composition and rheological properties of the pectin were determined. The influences of fat reduction and pectin addition on the physicochemical, rheological and sensory properties of low-fat ice cream were determined. The rheological results showed that pectin solutions were typical pseudoplastic fluids. The addition of pectin in ice cream can cause an increase in viscosity, overrun, and hardness, and a decrease in meltdown of the ice cream. When 0.72% pectin (w/w is incorporated into ice cream, a prototype product of ice cream with 45% lower fat content compared to the control was made. Results indicated that their qualities such as appearance, flavor, and taste were not significantly different. The low-fat ice cream had higher smoothness scores and lower mouth-coating scores. Hence, pectin extracted from citrus canning wastewater can be potentially used as fat replacer in ice cream, which benefits both the environment and the food industry.

  12. Preparation and quality characterization of soy milk based non-dairy ice cream

    Directory of Open Access Journals (Sweden)

    Samreen Ahsan

    2015-07-01

    Full Text Available Soy milk made from soybean has prospective to be used as a substitute of milk due to its health benefits. It is a rich source of iso-flavones, omega-3-fatty acid, dietary fiber, vitamin C, carotenoids, protein and oligosaccharides. The current study was designed to examine the effects of galacto-manan on ice cream by using commercially available (silk and locally prepared soy milk. Galacto-mannan (guar gum was used in different concentration (0.3, 0.4, 0.5 and 0.6% for the preparation of ice cream. Ice cream was analyzed for physico-chemical and sensory characteristics at 0, 30 and 60 days of storage interval. Overrun, meltdown, viscosity, total solids, pH and acidity were affected significantly by ice cream samples as well as storage. While non-significant effects of stabilizer and storage were found on fat, protein, and ash contents of ice cream. On organoleptic evaluation, the highest scores were awarded to the ice cream sample prepared with 0.5% of guar gum. Ice cream manufactured with locally prepared soy milk and guar gum revealed comparable quality with lower cost.

  13. Preparation and quality characterization of soy milk based non-dairy ice cream

    Directory of Open Access Journals (Sweden)

    Samreen Ahsan

    2015-08-01

    Full Text Available Soy milk made from soybean has prospective to be used as a substitute of milk due to its health benefits. It is a rich source of iso-flavones, omega-3-fatty acid, dietary fiber, vitamin C, carotenoids, protein and oligosaccharides. The current study was designed to examine the effects of galacto-manan on ice cream by using commercially available (silk and locally prepared soy milk. Galacto-mannan (guar gum was used in different concentration (0.3, 0.4, 0.5 and 0.6% for the preparation of ice cream. Ice cream was analyzed for physico-chemical and sensory characteristics at 0, 30 and 60 days of storage interval. Overrun, meltdown, viscosity, total solids, pH and acidity were affected significantly by ice cream samples as well as storage. While non-significant effects of stabilizer and storage were found on fat, protein, and ash contents of ice cream. On organoleptic evaluation, the highest scores were awarded to the ice cream sample prepared with 0.5% of guar gum. Ice cream manufactured with locally prepared soy milk and guar gum revealed comparable quality with lower cost.

  14. Assessment of mass fraction and melting temperature for the application of limestone concrete and siliceous concrete to nuclear reactor basemat considering molten core-concrete interaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jae; Kim, Do Gyeum [Korea Institute of Civil Engineering and Building Technology, Goyang (Korea, Republic of); Cho, Jae Leon [Korea Hydro and Nuclear Power Co., Ulsan (Korea, Republic of); Yoon, Eui Sik [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Cho, Myung Suk [Korea Hydro and Nuclear Power Co., Central Research Institute, Daejeon (Korea, Republic of)

    2016-04-15

    Severe accident scenarios in nuclear reactors, such as nuclear meltdown, reveal that an extremely hot molten core may fall into the nuclear reactor cavity and seriously affect the safety of the nuclear containment vessel due to the chain reaction caused by the reaction between the molten core and concrete. This paper reports on research focused on the type and amount of vapor produced during the reaction between a high-temperature molten core and concrete, as well as on the erosion rate of concrete and the heat transfer characteristics at its vicinity. This study identifies the mass fraction and melting temperature as the most influential properties of concrete necessary for a safety analysis conducted in relation to the thermal interaction between the molten core and the basemat concrete. The types of concrete that are actually used in nuclear reactor cavities were investigated. The H2O content in concrete required for the computation of the relative amount of gases generated by the chemical reaction of the vapor, the quantity of CO2 necessary for computing the cooling speed of the molten core, and the melting temperature of concrete are evaluated experimentally for the molten core-concrete interaction analysis.

  15. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

    Energy Technology Data Exchange (ETDEWEB)

    Ohishi, Yuji, E-mail: ohishi@see.eng.osaka-u.ac.jp [Graduate School of Engineering, Osaka University (Japan); Kondo, Toshiki [Graduate School of Engineering, Osaka University (Japan); Ishikawa, Takehiko [Japan Aerospace Exploration Agency (Japan); SOKEN-DAI (Graduate University for Advanced Studies) (Japan); Okada, Junpei T. [Institute for Materials Research, Tohoku University (Japan); Watanabe, Yuki [Advanced Engineering Services Co. Ltd. (Japan); Muta, Hiroaki; Kurosaki, Ken [Graduate School of Engineering, Osaka University (Japan); Yamanaka, Shinsuke [Graduate School of Engineering, Osaka University (Japan); Research Institute of Nuclear Engineering, University of Fukui (Japan)

    2017-03-15

    It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 0.77}Cr{sub 0.23}) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr{sub 1-x}Ni{sub x} (x = 0.12 and 0.24) and Zr{sub 77}Cr{sub 23}. • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

  16. Physical properties of molten core materials: Zr-Ni and Zr-Cr alloys measured by electrostatic levitation

    International Nuclear Information System (INIS)

    Ohishi, Yuji; Kondo, Toshiki; Ishikawa, Takehiko; Okada, Junpei T.; Watanabe, Yuki; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2017-01-01

    It is important to understand the behaviors of molten core materials to investigate the progression of a core meltdown accident. In the early stages of bundle degradation, low-melting-temperature liquid phases are expected to form via the eutectic reaction between Zircaloy and stainless steel. The main component of Zircaloy is Zr and those of stainless steel are Fe, Ni, and Cr. Our group has previously reported physical property data such as viscosity, density, and surface tension for Zr-Fe liquid alloys using an electrostatic levitation technique. In this study, we report the viscosity, density, and surface tension of Zr-Ni and Zr-Cr liquid alloys (Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 0.77 Cr 0.23 ) using the electrostatic levitation technique. - Highlights: • The physical properties of Zr-Ni and Zr-Cr liquid alloys have been measured Zr 1-x Ni x (x = 0.12 and 0.24) and Zr 77 Cr 23 . • The measurement was conducted using the electrostatic levitation technique. • The density, viscosity, and surface tension of each liquid alloy were measured.

  17. Mitigating Mitochondrial Genome Erosion Without Recombination.

    Science.gov (United States)

    Radzvilavicius, Arunas L; Kokko, Hanna; Christie, Joshua R

    2017-11-01

    Mitochondria are ATP-producing organelles of bacterial ancestry that played a key role in the origin and early evolution of complex eukaryotic cells. Most modern eukaryotes transmit mitochondrial genes uniparentally, often without recombination among genetically divergent organelles. While this asymmetric inheritance maintains the efficacy of purifying selection at the level of the cell, the absence of recombination could also make the genome susceptible to Muller's ratchet. How mitochondria escape this irreversible defect accumulation is a fundamental unsolved question. Occasional paternal leakage could in principle promote recombination, but it would also compromise the purifying selection benefits of uniparental inheritance. We assess this tradeoff using a stochastic population-genetic model. In the absence of recombination, uniparental inheritance of freely-segregating genomes mitigates mutational erosion, while paternal leakage exacerbates the ratchet effect. Mitochondrial fusion-fission cycles ensure independent genome segregation, improving purifying selection. Paternal leakage provides opportunity for recombination to slow down the mutation accumulation, but always at a cost of increased steady-state mutation load. Our findings indicate that random segregation of mitochondrial genomes under uniparental inheritance can effectively combat the mutational meltdown, and that homologous recombination under paternal leakage might not be needed. Copyright © 2017 by the Genetics Society of America.

  18. Recriticality, a Key Phenomenon to Investigate in Core Disruptive Accident Scenarios of Current and Future Fast Reactor Designs

    International Nuclear Information System (INIS)

    Maschek, W.; Rineiski, A.; Flad, M.; Kriventsev, V.; Gabrielli, F.; Morita, K.

    2012-01-01

    Final comments and conclusions: • Modern plants, should have performed better under Fukushima type event. • In future fast reactor systems significantly higher active and passive safety features are installed, which should cope with events like Fukushima. • One important lesson: put a focus on rare initiators, accident routes and consequences that are neither expected nor have been observed, events that are categorized under ‘black swans’. • Importance of severe accident research demonstrated - both analytically and experimentally for assessing and interpreting accident scenarios and developments. Precondition for developing preventive & mitigative safety measures. Passive safety measures are in the focus of advanced design options and must work under conditions of multiple loads and aggravating events. • Fast reactor systems behavior as the SFR under severe accident conditions: – In fast spectrum systems as the SFR the core is not in its neutronically most reactive configuration and SFRs may be loaded with MAs for waste management; – Recriticalities have a high probability because of the higher enrichment levels; – Short time scales have to be envisioned for core melt-down; – Decay heat levels might be significantly higher, if MA bearing fuel is involved. • Improve design by measures for prevention and/or mitigation of recriticalities; – High reliability of simulations required for proof; • Assessment of fuel relocated on peripheral structures; • Preventive/mitigating measures should not replace containment measures

  19. HISTORICAL AMERICAN ENGINEERING RECORD - IDAHO NATIONAL ENGINEERING AND ENVIRONMENTAL LABORATORY, TEST AREA NORTH, HAER NO. ID-33-E

    Energy Technology Data Exchange (ETDEWEB)

    Susan Stacy; Hollie K. Gilbert

    2005-02-01

    Test Area North (TAN) was a site of the Aircraft Nuclear Propulsion (ANP) Project of the U.S. Air Force and the Atomic Energy Commission. Its Cold War mission was to develop a turbojet bomber propelled by nuclear power. The project was part of an arms race. Test activities took place in five areas at TAN. The Assembly & Maintenance area was a shop and hot cell complex. Nuclear tests ran at the Initial Engine Test area. Low-power test reactors operated at a third cluster. The fourth area was for Administration. A Flight Engine Test facility (hangar) was built to house the anticipated nuclear-powered aircraft. Experiments between 1955-1961 proved that a nuclear reactor could power a jet engine, but President John F. Kennedy canceled the project in March 1961. ANP facilities were adapted for new reactor projects, the most important of which were Loss of Fluid Tests (LOFT), part of an international safety program for commercial power reactors. Other projects included NASA's Systems for Nuclear Auxiliary Power and storage of Three Mile Island meltdown debris. National missions for TAN in reactor research and safety research have expired; demolition of historic TAN buildings is underway.

  20. Deep into the discourse of the Spanish crisis: The deployment of English lexical incorporations to translate the untranslatable

    Directory of Open Access Journals (Sweden)

    María Ángeles Orts

    2012-04-01

    Full Text Available The Spanish economic boom over the last decade, and its subsequent swift progress to economic meltdown within the context of the Global Systemic Crisis, has popularized the deployment of an array of loanwords from English as the lingua franca of Economics. Incorporations in various shapes and forms are borrowed by the national think-tanks and the media to portray the widespread gloom and the severe wobbles in Spain's market. Through the analysis of an ad hoc 800,000-word corpus from economic news-items in specialised, semi-specialised and informative digital periodicals, the aid of a number of financial bilingual glossaries intended for the specialised Spanish-speaking community, and the exploitation of a specific taxonomy on linguistic incorporations − deployed in our previous study on the subject (Orts & Almela, 2009 − we have developed a system of lexical selection that reunites, analyzes and explains a representative group of real data. In doing so, our present study delves into the lexicon of the financial mayhem, in the attempt to enlighten and facilitate the translator’s task when dealing with the plethora of English loans in the Spanish economic discourse, and the way in which these are tackled by standardized sources.

  1. Electrical impedance scanning - application of this new technique for lymph node evaluation in children

    Energy Technology Data Exchange (ETDEWEB)

    Mentzel, Hans-Joachim; Malich, Ansgar; Freesmeyer, Martin; Boettcher, Joachim; Vogt, Susanna; Kaiser, Werner A. [Institute of Diagnostic and Interventional Radiology, University of Jena, Bachstrasse 18, 07740 Jena (Germany); Kentouche, Karim; Gruhn, Bernd; Zintl, Felix [Department of Pediatrics, University of Jena, Jena (Germany); Schneider, Gerlind [Department of Otorhinolaryngology, University of Jena, Jena (Germany); Anderson, Roselle [Siemens-Elema, Elema (Sweden)

    2003-07-01

    Precise assessment of lymph nodes is crucial to the choice of therapy and prediction of outcome in cases of malignancy. Electrical impedance scanning (EIS) is being experimentally investigated for potential use as a diagnostic tool for differentiation of malignant lesions. Malignancies show different electrical properties with changes in conductivity and capacitance that can be analysed by EIS. Using a TransScan TS-2000 (TransScan Medical, Migdal Ha'Emek, Israel, distributed by Siemens-Elema AB, Solna, Sweden), EIS has been used in various studies for the identification of breast cancer as well as for characterisation of superficial lesions. To evaluate the reliability of EIS for classifying lymph nodes in a pediatric population with sonographically suspicious lesions and to prove its accuracy. The study population consisted of 77 children (42 boys, 35 girls) aged 1.1-17.1 years. All EIS results were compared to either histopathological findings or long-term follow-up investigations. Sensitivity for malignancies using EIS was 75% and specificity was 87%. The negative predictive value was 93% and the positive predictive value was 60%. This study suggests the potential usefulness of EIS as an additional imaging modality for the differentiation of lymph-node diseases in children. The histopatholgical spectrum of malignant lymph node transformation in children compared to studies in adults, and the characteristic meltdown in inflammatory or granulomatous transformed nodes, pose challenges to differentiation based on sonographic evaluation, and also to EIS classification. (orig.)

  2. Post-accident heat removal research: A state of the art review

    International Nuclear Information System (INIS)

    Mueller, U.; Schulenberg, T.

    1983-11-01

    For a realistic assessment of the consequence of extremely unlikely reactor accidents resulting in core degradation or core meltdown key questions are how to remove the decay heat from the reactor system and how to retain the radioactive core debris within the containment. Usually, this complex of questions is referred to as Post-Accident Heat Removal (PAHR). In this article the research work on PAHR performed by various institutions during the last decade has been reviewed. The main results have been summarized under the chapter headings ''Accident Scenarios,'' - ''Core Debris Accommodation Concepts,'' and ''PAHR Topics.'' Particular emphasis has been placed on the presentation of the following problems: characteristics and coolability of solid core debris in the vector vessel, heat removal from molten pools of core material, and core-melt interaction with structural materials. Some unresolved or insufficiently answered questions relating to special ''PAHR Topics'' have been mentioned or discussed at the end of the particular Chapter. Problem areas of major uncertainty have been identified and listed at the end of the review article. They include the following subjects: formation of debris beds and bed characteristics, post dryout behaviour of particle beds, long-term availability and proper location of heat sinks, creep rupture of structures under high thermal loads. (orig.) [de

  3. NGL markets in North America: 1999--2005 competitive threats and opportunities

    International Nuclear Information System (INIS)

    Lippe, D.

    1999-01-01

    Gas processing contracts are structured in two basic ways. Gas plants are typically operated on a strict margin basis, on a percentage-of-proceeds basis, or on a keep-whole basis. Based on straight margins, percentage-of-proceeds or keep-whole contracts, gas processing profitability was weaker in 1998, than at any time during the past 10 years. No matter how gas processing profitability was measured, 1998 was the worst year in the history of gas processing since 1985. The economic disaster of 1998 prompted many gas plant operators to reevaluate their long-term participation in the industry. This paper reviews the root causes that resulted in the gas processing industry's economic meltdown in 1998. Trends in crude oil prices and natural gas prices determine the fundamental profitability for gas processing. Trends in ethylene production and ethylene industry profit margins determine the levels of demand for ethane and propane. This paper also highlights the prospects for recovery in profit margins, improvement in per gallon values and the potential for growth in total demand NGL and production

  4. National radiological emergency response to the Fukushima Daiichi Nuclear Power Plant accident

    International Nuclear Information System (INIS)

    Dela Rosa, Alumanda M.

    2011-01-01

    The Fukushima nuclear power plant accident occurred on March 11, 2011, when two natural disasters of unprecedented strengths, an earthquake with magnitude 9 followed one hour later by a powerful tsunami struck northeastern Japan and felled the external power supply and the emergency diesel generators of the Fukushima Daiichi nuclear power station, resulting in a loss of coolant accident. There were core meltdowns in three nuclear reactors with the release of radioactivity estimated to be 1/10 of what was released to the environment during the Chernobyl nuclear power plant accident in April 1986. The Fukushima nuclear accident tested the capability of the Philippine Nuclear Research Institute (PNRI) and the National Disaster Risk Reduction and Management Council (NDRRMC) in responding to such radiological emergency as a nuclear power plant accident. The PNRI and NDRRMC activated the RADPLAN for possible radiological emergency. The emergency response was calibrated to the status of the nuclear reactors on site and the environmental monitoring undertaken around the site and off-site, including the marine environment. This orchestrated effort enabled the PNRI and the national agencies concerned to reassure the public that the nuclear accident does not have a significant impact on the Philippines, both on the health and safety of the people and on the safety of the environment. National actions taken during the accident will be presented. The role played by the International Atomic Energy Agency as the central UN agency for nuclear matters will be discussed. (author)

  5. Preliminary Evaluations of CSPACE for a Station Blackout Transient in APR1400

    Energy Technology Data Exchange (ETDEWEB)

    Lee, T. B.; Lee, D. K.; Lee, H. S.; Lee, G. W.; Choi, T. S. [KEPCO, Daejeon (Korea, Republic of); Park, R. J.; Kim, D. H. [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    This paper discusses the preliminary results of the simulated station blackout (SBO) transients using the CSPACE code and presents the information pertinent to the related safety issues. CSPACE is a merged program of a master processer of Safety and Performance Analysis Code (SPACE) for nuclear power plants and a child processer of Core Meltdown Progression Accident Simulation Software (COMPASS) generated as a dynamic-link library (DLL) codes. It has been developed to predict the best-estimate transient in the pressurized water reactor (PWR) for severe accidents. SPACE and COMPASS codes take charge of the thermal-hydraulic response of PWRs and the analysis of the severe accident progression in a vessel, respectively. The initial phase is estimated starting from time zero when the loss of off-site and on-site powers occurs simultaneously. Shortly after the RCS pressure initially falls and rises slightly due to the effects of the reactor and turbine trips, the RCS pressure declines in response to the cooling provided by heat removed to the SGs. During the period of the primary heat-up and boil-off, the RCS pressure increase is limited by two cycles of the POSRV. The RCS fluid mass is lost through the pressurizer POSRV and then the core uncovers and superheated steam flows out from the RV into the coolant loops starting at 5513.0 seconds.

  6. Status report on the deflagration/detonation transition in the three-phase diagram hydrogen/air/steam according to Shapiro/Moffette

    International Nuclear Information System (INIS)

    Mayinger, F.; Strube, G.; Beauvais, R.

    1988-01-01

    On the basis of a bibliographic study, the present level of knowledge about the combustion of hydrogen/air/steam mixtures, in particular, knowledge about transition from deflagration to detonation (DDT) is recorded. The numerical calculation of combustion processes produces good results; at present, however, a comprehensive simulation of highly turbulent flames is not yet possible. A consistent model for DDT based on the instability of highly turbulent flame fronts with high spreading rates is capable of explaining the transitions to detonation found in a diversity of test arrangements. At the same time, the same model provides a criterion with which conservative limits for DDT can be determined in the three-component diagram. It is extremely difficult to give a reliable estimate of the situation of H 2 in hypothetical developments of heavy core meltdown accidents with the help of the limits found. All that can be said at present is that danger originating from hydrogen can only arise after concrete melt interaction has taken place. In this case, DDT cannot be precluded, at least in some compartments of the safety vessel. (orig.) [de

  7. Nuclear energy–Any solution for sustainability and climate protection?

    International Nuclear Information System (INIS)

    Mez, Lutz

    2012-01-01

    For the future of nuclear power it will be decisive whether or not nuclear fission technologies offer a sustainable solution to global energy problems. The impressive expansion of nuclear reactors in the 1960s and 1970 slowed down after the meltdown in Harrisburg and the nuclear explosion in Chernobyl. Since the end of the 1980s installed nuclear capacity has stagnated, and in Europe declined. However, a nuclear revival or renaissance has been predicted for 30 years. This article reviews global scenarios and national nuclear programmes and analyses problems in the nuclear industry. Special attention is given to nuclear power and global warming and the nexus between nuclear power and nuclear proliferation. - Highlights: ► The status of nuclear programmes in the world is examined. ► Nuclear power has taken a nose-dive in Western industrialised countries. ► The nuclear renaissance has been announced since 1981 but never materialised. ► Share of nuclear power is 15.7% of global electricity but only 2.3% of global FEC. ► Nuclear energy is no sustainable solution and cannot avoid global warming.

  8. Analyzing Malaysians’ perception of risk in developing radiological and nuclear crisis communication framework

    International Nuclear Information System (INIS)

    Hamid, AHA.; Hassan, H.; Ramanathan, B.; Jumat, AH.; Jaafar, NNH.; Abdullah, A.

    2015-01-01

    Crisis communication is an indicator of a sustaining public normalcy that serves to control and decrease any untoward situations during disasters’ meltdown. Prior findings highlighted that 25.85 percent of arising organizational disputes can be resolved using public announcements and an enhancement of public awareness through avoiding related dissatisfactions, disorders and untoward circumstances during radiation and nuclear emergencies. Hence, in this paper, we are interrogating Malaysians on their perception of risk regarding to radiation and nuclear disasters and emergencies. The principal aim is to identify the relationship between the IAEA’s initiated risk perception characteristics and the content of the respective public acceptance reports. Those relationships are described and analyzed into a network diagram using the ATLAS.ti software consisting of Clustering and C-Coefficient analyses. This diagram identifies the main variables relating to significant characteristics of risk perception. Future studies should further evaluate the intensity of public opinion against the suggested constructs of executing a thorough and structured risk management mechanism, to advance public trust as well as crisis communication

  9. Observations on the Chernobyl Disaster and LNT

    Science.gov (United States)

    Jaworowski, Zbigniew

    2010-01-01

    The Chernobyl accident was probably the worst possible catastrophe of a nuclear power station. It was the only such catastrophe since the advent of nuclear power 55 years ago. It resulted in a total meltdown of the reactor core, a vast emission of radionuclides, and early deaths of only 31 persons. Its enormous political, economic, social and psychological impact was mainly due to deeply rooted fear of radiation induced by the linear non-threshold hypothesis (LNT) assumption. It was a historic event that provided invaluable lessons for nuclear industry and risk philosophy. One of them is demonstration that counted per electricity units produced, early Chernobyl fatalities amounted to 0.86 death/GWe-year), and they were 47 times lower than from hydroelectric stations (∼40 deaths/GWe-year). The accident demonstrated that using the LNT assumption as a basis for protection measures and radiation dose limitations was counterproductive, and lead to sufferings and pauperization of millions of inhabitants of contaminated areas. The projections of thousands of late cancer deaths based on LNT, are in conflict with observations that in comparison with general population of Russia, a 15% to 30% deficit of solid cancer mortality was found among the Russian emergency workers, and a 5% deficit solid cancer incidence among the population of most contaminated areas. PMID:20585443

  10. Researches in nuclear safety

    International Nuclear Information System (INIS)

    Souchet, Y.

    2009-01-01

    This article comprises three parts: 1 - some general considerations aiming at explaining the main motivations of safety researches, and at briefly presenting the important role of some organisations in the international conciliation, and the most common approach used in safety researches (analytical experiments, calculation codes, global experiments); 2 - an overview of some of the main safety problems that are the object of worldwide research programs (natural disasters, industrial disasters, criticality, human and organisational factors, fuel behaviour in accidental situation, serious accidents: core meltdown, corium spreading, failure of the confinement building, radioactive releases). Considering the huge number of research topics, this part cannot be exhaustive and many topics are not approached; 3 - the presentation of two research programs addressing very different problems: the evaluation of accidental releases in the case of a serious accident (behaviour of iodine and B 4 C, air infiltration, fission products release) and the propagation of a fire in a facility (PRISME program). These two programs belong to an international framework involving several partners from countries involved in nuclear energy usage. (J.S.)

  11. International standard problem ISP37: VANAM M3 - A Multi compartment aerosol depletion test with hygroscopic aerosol material: comparison report

    International Nuclear Information System (INIS)

    Firnhaber, M.; Kanzleiter, T.F.; Schwarz, S.; Weber, G.

    1996-12-01

    This paper presents the results and assessment of the 'open' ISP37, which deals with the containment thermal-hydraulics and aerosol behavior during an unmitigated severe LWR accident with core melt-down and steam and aerosol release into the containment. Representatives of 22 organizations participated to the ISP37 using the codes CONTAIN, FIPLOC, MELCOR, RALOC, FUMO, MACRES, REMOVAL etc. The containment and aerosol behavior experiment VANAM M3 was selected as experimental comparison basis. The main phenomena investigated are the thermal behavior of a multi-compartment containment, e.g. pressure, temperature and the distribution and depletion of a soluble aerosol. The ISP37 has demonstrated that the codes used could calculate the thermal-hydraulic containment behavior in general with sufficient accuracy. But with respect to the needs of aerosol behavior analysis the accuracies, both analytical and experimental as well, for specific thermal-hydraulic variables should be improved. Although large progress has been made in the simulation of aerosol behavior in multi-compartment geometries the calculated local aerosol concentrations scatter widely. However, the aerosol source term to the environment is overestimated in general. The largest uncertainty concerning the aerosol results is caused by a limited number of thermal hydraulic variables like relative humidity, volume condensation rate and atmospheric flow rate. In some codes also a solubility model is missing

  12. Comparison of multiphase mixing simulations performed on a staggered and a collocated grid

    International Nuclear Information System (INIS)

    Leskovar, M.

    2000-01-01

    During a severe reactor accident following core meltdown when the molten fuel comes into contact with the coolant water a steam explosion may occur. The premixing phase of a steam explosion covers the interaction of the melt jet or droplets with the water prior to any steam explosion occurrence. To get a better insight of the hydrodynamic processes during the premixing phase beside hot premixing experiments, where the water evaporation is significant, also cold isothermal premixing experiments are performed. To analyze the cold premixing experiments the computer code ESE has been developed. The specialty of ESE is that it uses a combined single-multiphase flow model. Because of problems with the convergence of the momentum equation written in conservative form on a staggered grid, the development of a collocated grid version of ESE was planed. But since we obtained the commercial code CFX-4.3, which uses a collocated variable arrangement, we decided first to test the capabilities of CFX-4.3. With ESE and CFX-4.3 the cold premixing experiment Q08 has been simulated. In the paper the simulation results performed with both codes are presented and commented in comparison to experimental data. (author)

  13. Structure and experimental program for SNEAK 12 - an assembly for fast breeder safety experiments

    International Nuclear Information System (INIS)

    Helm, F.

    1979-01-01

    The critical assembly SNEAK 12 and its foreseen experimental program have the main purpose to check the validity of neutron physics calculational methods used in the analysis of accidental situations of fast breeder reactors. In the investigation of accidental courses configurations have to be considered, which are caused by assembly deformation and meltdown and which are characterized by irregular fuel and structural material arrangements with cavities and empty channels. The reactivity differences between the unperturbed core and a series of perturbed configurations have to be determined. The individual configurations have to be chosen in such a way, that the calculational methods for the different aspects of the accident sequence (formation of cavities and channels, relocation of fissile and fertile material and steel) can be tested one by one. Two different cores are foreseen: SNEAK 12A as a one-zone core with enriched uranium fuel and SNEAK 12B with a central test zone with plutonium-uranium mixed-oxide fuel surrounded by a driver zone of enriched uranium. The report describes these cores and their assemblies, and the experimental program is outlined

  14. Overview of plant specific source terms and their impact on risk

    International Nuclear Information System (INIS)

    Desaedeleer, G.

    2004-01-01

    Probabilistic risk assesment and safety assessment focuses on systems and measures to prevent core meltdown, and it integrates many aspects of design and operation. It provides mapping of initiating event, frequencies onto plant damage state and through plant systems analysis, utilizes fault tree and event tree logic models, may include 'external event' analysis such as fire, flood, wind, seismic events. Percent contribution of sequences to the core damage frequency are shown for the following plants, taken as examples ZION, EDISON, OCONEE 3, SEABROOK, SIZEWELL B, MILLSTONE 3, RINGHALS 2. The presentation includes comparison of the following initiating event frequencies: loss of off-site power; small LOCA; large LOCA, steam generator tube rupture; loss of feedwater; turbine trip; reactor trip. Consequence analysis deals with: dispersion and depletion of radioactivity in the atmosphere, health effects, factors in the off-site emergency plan analyzed with codes that address the weather conditions; provision of mapping of source terms; risk diagram for early fatalities and for latent cancer fatalities

  15. THE SOCIAL-ECONOMIC IMPLICATIONS OF THE CLIMATE CHANGES IN ROMANIA

    Directory of Open Access Journals (Sweden)

    Gheorghe ZAMAN

    2005-12-01

    Full Text Available The social-economic implication of climatic changes in Romania are analysed under the following viewpoints: causes and effects; prevention and abatement; adjustment; institutional aspects of environmental management. The main reason of climatic changes is generated by the greenhouse effect (GE that determines the heating of the terrestrial surface, melt-down of icebergs, tornados, draughts and flooding more frequently and of increasing intensity. These extreme meteorological phenomena determine, over time, increasing human and material losses, which imposes measures with effects on short-, medium- and long-term for diminishing the greenhouse effect in accordance with the commitments and provisions of the Kyoto Protocol and the requirements for the sustainable development of the country. Proposals are made with respect to integrating environmental issues into economic and social development strategies, emphasising the need for increasing environment financing and attaching more importance to the Ministry of Environment which must couple its policy with the acquis communautaire and the EU programme for combating and preventing GE impact.

  16. A review of experiments and results from the TREAT facility

    International Nuclear Information System (INIS)

    Deitrich, L.W.; Dickerman, C.E.; Klickman, A.E.; Wright, A.E.

    1998-01-01

    The Transient Reactor Test (TREAT) facility was designed and built in the late 1950s at Argonne National Laboratory (ANL) to provide a transient reactor for safety experiments on samples of reactor fuels. It first operated in 1959. Throughout its history, experiments conducted in TREAT have been important in establishing the behavior of a wide variety of reactor fuel elements under conditions predicted to occur in reactor accidents ranging from mild off-normal transients to hypothetical core disruptive accidents. For much of its history, TREAT was used primarily to test liquid-metal reactor fuel elements, initially for the Experimental Breeder Reactor-II (EBR-II), then for the Fast Flux Test Facility (FFTF), the Clinch River Breeder Reactor Plant (CRBRP), the British Prototype Fast Reactor (PFR), and finally for the Integral Fast Reactor (IFR). Both oxide and metal elements were tested in dry capsules and in flowing sodium loops. The data obtained were instrumental in establishing the behavior of the fuel under off-normal and accident conditions, a necessary part of the safety analysis of the various reactors. In addition, TREAT was used to test light water reactor (LWR) elements in a steam environment to obtain fission product release data under meltdown conditions. Studies are now under way on applications of TREAT to testing of the behavior of high-burnup LWR elements under reactivity-initiated accident (RIA) conditions using a high-pressure water loop

  17. Source term and behavioural parameters for a postulated HIFAR loss-of-coolant accident

    International Nuclear Information System (INIS)

    May, F.G.

    1987-01-01

    The fraction of the fission product inventory which might be released into the atmosphere of the HIFAR reactor containment building (RCB) during a postulated loss-of-coolant accident (LOCA) has been evaluated as a function of time, for each classification of airborne radioactivity. This appraisal will be used as the source term for a computer program, which uses realistic attenuation of the fission product aerosol in a single compartment model with a defined leakrate to predict possible radioactive releases into the environment in a hypothetical bounding case reactor accident which is rather more severe in all major aspects than any single LOCA. Also given are the parameters governing the attenuation of the aerosol and vapours in the atmosphere of the RCB so that their behaviour may be accurately modelled. The source terms for several other types of accident involving the meltdown of fuel elements have also been considered but in less detail than the LOCA case. In some of the cases, the fission products are released directly to atmosphere, so there is no attenuation of the release by deposition within the RCB

  18. Posttest examination of the VVER-1000 fuel rod bundle CORA-W2

    International Nuclear Information System (INIS)

    Sepold, L.

    1995-06-01

    The bundle meltdown experiment CORA-W2, representing the behavior of a Russian type VVER-1000 fuel element, with one B 4 C/stainless steel absorber rod was selected by the OECD/CSNI as International Standard Problem (ISP-36). The experimental results of CORA-W2 serve as data base for comparison with analytical predictions of the high-temperature material behavior by various code systems. The first part of the experimental results is described in KfK 5363 (1994), the second part is documented in this report which contains the destructive post-test examination results. The metallographical and analytical (SEM/EDX) post-test examinations were performed in Germany and Russia and are summarized in five individual contributions. The upper half of the bundle is completely oxidized, the lower half has kept the fuel rods relatively intact. The post-test examination results show the strong impact of the B 4 C absorber rod and the stainless steel grid spacers on the ''low-temperature'' bundle damage initiation and progression. The B 4 C absorber rod completely disappeared in the upper half of the bundle. The multicomponent melts relocated and formed coolant channel blockages on solidification with a maximum extent of about 30% in the lower part of the bundle. At temperatures above the melting point of the ZrNb1 cladding extensive fuel dissolution occurred. (orig.) [de

  19. Mobilizing Mothers: The Fukushima Daiichi Nuclear Catastrophe and Environmental Activism in Japan

    Directory of Open Access Journals (Sweden)

    Nicole Freiner

    2014-02-01

    Full Text Available The citizens’ and environmental movements of the 1960s and 70s hadgreat political success in Japan, culminating in the Special Session of the Diet in1970 that enacted 14 anti-pollution laws. These activist groups fought denials ofresponsibility on the part of industry and unresponsiveness on the part of localgovernments. Women were at the forefront of this type of activism during the 1960sand 70s, and led many of the citizens’ environmental movements during this time.More recently, during the environmental catastrophe caused by the meltdown of theFukushima Daiichi nuclear plant, women and mothers have been vocal protesters.Environmental movements have particular political salience because of the successwomen have achieved in this area both in policy change and also roles in formalpolitics. Women have consistently achieved these successes at the same time as theyperformed their roles as mothers and home managers; these roles have been usedstrategically to mobilize women with great effect, and also were central to the valueswith which the citizens’ movements defined themselves politically.

  20. Analysis of Survey Results of the Public's Perceptions of Nuclear Energy

    International Nuclear Information System (INIS)

    Kim, Dongwon

    2008-01-01

    In the 1970s when the two oil shocks occurred, nuclear energy was recognized as an economic and reliable source of electricity, and the nuclear power industry smoothly developed without much difficulty in the selection of reactor sites, etc. Amid such favorable circumstances, the government and nuclear energy companies gave short shrift to ensuring the public's correct understanding of nuclear energy. The perception of nuclear energy began to deteriorate in the latter half of the 1980s. With the accident at the Three Mile Island nuclear reactor no. 2 in the U. S. in 1979 and the melt-down of Chernobyl nuclear power came to the fore. In addition, the changes in the political and social environment wrought by the democratization movement made the continued development of the nuclear energy industry very difficult. The government had no choice but to seek peoples due to a number of factors including the emergence of a new social atmosphere in which individual freedom and human rights were emphasized over material abundance; increased opposition to nuclear energy by environmental groups that appeared during the course of democratization; antipathy against the previous authoritarian governments; and the people's increased demands for the right to know, etc. The nuclear energy industry also could not conduct its business, including the securing of sites for power plants and nuclear waste, without the people's concurrence