Mitigating reentry radio blackout by using a traveling magnetic field

Directory of Open Access Journals (Sweden)

Hui Zhou

2017-10-01

Full Text Available A hypersonic flight or a reentry vehicle is surrounded by a plasma layer that prevents electromagnetic wave transmission, which results in radio blackout. The magnetic-window method is considered a promising means to mitigate reentry communication blackout. However, the real application of this method is limited because of the need for strong magnetic fields. To reduce the required magnetic field strength, a novel method that applies a traveling magnetic field (TMF is proposed in this study. A mathematical model based on magneto-hydrodynamic theory is adopted to analyze the effect of TMF on plasma. The mitigating effects of the TMF on the blackout of typical frequency bands, including L-, S-, and C-bands, are demonstrated. Results indicate that a significant reduction of plasma density occurs in the magnetic-window region by applying a TMF, and the reduction ratio is positively correlated with the velocity of the TMF. The required traveling velocities for eliminating the blackout of the Global Positioning System (GPS and the typical telemetry system are also discussed. Compared with the constant magnetic-window method, the TMF method needs lower magnetic field strength and is easier to realize in the engineering field.

Mitigating reentry radio blackout by using a traveling magnetic field

Science.gov (United States)

Zhou, Hui; Li, Xiaoping; Xie, Kai; Liu, Yanming; Yu, Yuanyuan

2017-10-01

A hypersonic flight or a reentry vehicle is surrounded by a plasma layer that prevents electromagnetic wave transmission, which results in radio blackout. The magnetic-window method is considered a promising means to mitigate reentry communication blackout. However, the real application of this method is limited because of the need for strong magnetic fields. To reduce the required magnetic field strength, a novel method that applies a traveling magnetic field (TMF) is proposed in this study. A mathematical model based on magneto-hydrodynamic theory is adopted to analyze the effect of TMF on plasma. The mitigating effects of the TMF on the blackout of typical frequency bands, including L-, S-, and C-bands, are demonstrated. Results indicate that a significant reduction of plasma density occurs in the magnetic-window region by applying a TMF, and the reduction ratio is positively correlated with the velocity of the TMF. The required traveling velocities for eliminating the blackout of the Global Positioning System (GPS) and the typical telemetry system are also discussed. Compared with the constant magnetic-window method, the TMF method needs lower magnetic field strength and is easier to realize in the engineering field.

Impact assessment of the 1977 New York City blackout. Final report

Energy Technology Data Exchange (ETDEWEB)

Corwin, J. L.; Miles, W. T.

1978-07-01

This study was commissioned by the Division of Electric Energy Systems (EES), Department of Energy (DOE) shortly after the July 13, 1977 New York City Blackout. The objectives were two-fold: to assess the availability and collect, where practical, data pertaining to a wide variety of impacts occurring as a result of the blackout; and to broadly define a framework to assess the value of electric power reliability from consideration of the blackout and its effects on individuals, businesses, and institutions. The impacts were complex and included both economic and social costs. In order to systematically classify the most significant of these impacts and provide guidance for data collection, impact classification schemes were developed. Major economic impact categories examined are business; government; utilities (Consolidated Edison); insurance industry; public health services; and other public services. Impacts were classified as either direct or indirect depending upon whether the impact was due to a cessation of electricity or a response to that cessation. The principal economic costs of the blackout are shown. Social impacts, i.e., the changes in social activities and adaptations to these changes were particularly significant in New York due to its unique demographic and geographic characteristics. The looting and arson that accompanied the blackout set aside the NYC experience from other similar power failures. (MCW)

Reactor coolant pump shaft seal stability during station blackout

International Nuclear Information System (INIS)

Rhodes, D.B.; Hill, R.C.; Wensel, R.G.

1987-05-01

Results are presented from an investigation into the behavior of Reactor Coolant Pump shaft seals during a potential station blackout (loss of all ac power) at a nuclear power plant. The investigation assumes loss of cooling to the seals and focuses on the effect of high temperature on polymer seals located in the shaft seal assemblies, and the identification of parameters having the most influence on overall hydraulic seal performance. Predicted seal failure thresholds are presented for a range of station blackout conditions and shaft seal geometries

Reactor coolant pump shaft seal stability during station blackout

Energy Technology Data Exchange (ETDEWEB)

Rhodes, D B; Hill, R C; Wensel, R G

1987-05-01

Results are presented from an investigation into the behavior of Reactor Coolant Pump shaft seals during a potential station blackout (loss of all ac power) at a nuclear power plant. The investigation assumes loss of cooling to the seals and focuses on the effect of high temperature on polymer seals located in the shaft seal assemblies, and the identification of parameters having the most influence on overall hydraulic seal performance. Predicted seal failure thresholds are presented for a range of station blackout conditions and shaft seal geometries.

Blackouts as a Moderator of Young Adult Veteran Response to Personalized Normative Feedback for Heavy Drinking.

Science.gov (United States)

Miller, Mary Beth; DiBello, Angelo M; Carey, Kate B; Pedersen, Eric R

2018-06-01

Blackouts-or periods of alcohol-induced amnesia for all or part of a drinking event-have been identified as independent predictors of alcohol-related harm that may be used to identify individuals who would benefit from intervention. However, little is known about the prevalence and impact of blackouts among Veterans. This study examined blackouts as a moderator of young adult veteran response to a brief, online personalized normative feedback (PNF) intervention for heavy drinking. Veterans scoring ≥3/4 (women/men) on the Alcohol Use Disorders Identification Test completed a baseline and 1-month assessment as part of a larger intervention trial (N = 571; 83% male; age M = 28.9, SD = 3.3). Participants were randomized to alcohol PNF (n = 285) or a video game attention control (n = 286). Hierarchical regression was used to examine the interaction between intervention condition and blackouts on alcohol-related outcomes at 1-month follow-up. At baseline, 26% of participants reported loss of memory for drinking events in the past 30 days. The interaction between condition and blackouts was significant, such that PNF participants who had experienced blackouts at baseline reported greater decreases in drinking quantity at 1 month than those who had not, and only PNF participants who had experienced baseline blackouts reported a decrease in alcohol problems at follow-up. PNF appears to be particularly effective for individuals who have experienced alcohol-induced blackout, perhaps because blackouts prime them for feedback on their alcohol use. While other negative consequences may also prime individuals for behavior change, blackouts are posited as a particularly useful screening tool because they are prevalent among young adults, have a strong association with alcohol-related harm, and are assessed in widely used clinical measures. Copyright © 2018 by the Research Society on Alcoholism.

Blackout cloth for dormancy induction

Science.gov (United States)

Tom Jopson

2007-01-01

The use of blackout cloth to create long night photoperiods for the induction of dormancy in certain conifer species has been an established practice for a long time. Its use was suggested by Tinus and McDonald (1979) as an effective technique, and the practice has been commonly used in Canadian forest nurseries for a number of years. Cal-Forest Nursery installed its...

Toward quantification of the uncertainty in estimating frequency of critical station blackout

International Nuclear Information System (INIS)

Rodgers, Shawn; Betancourt, Coral; Kee, Ernie; Nelson, Paul; Rodi, Paul

2011-01-01

A formal statement of the critical station blackout problem is provided, and a solution given, up to evaluation of an n-dimensional 'non recovery integral' n =number of trains (parallel backup sources of electrical power). Several approaches that have been developed in the industry to estimate probability of critical station blackout are shown to be interpretable as special cases of such integrals. Computational results, for a simple model problem, suggest there is yet a very substantial over conservatism in current state-of-the-art techniques for estimating probability of critical station blackout. Research issues associated to possibly meeting this need via computational evaluation of the non recovery integral are discussed. (author)

Learning from the blackouts. Transmission system security in competitive electricity markets

Energy Technology Data Exchange (ETDEWEB)

none

2005-07-01

Electricity market reform has fundamentally changed the environment for maintaining reliable and secure power supplies. Growing inter-regional trade has placed new demands on transmission systems, creating a more integrated and dynamic network environment with new real-time challenges for reliable and secure transmission system operation. Despite these fundamental changes, system operating rules and practices remain largely unchanged. The major blackouts of 2003 and 2004 raised searching questions about the appropriateness of these arrangements. Management of system security needs to be transformed to maintain reliable electricity services in this more dynamic operating environment. These challenges raise fundamental issues for policymakers. This publication presents case studies drawn from recent large-scale blackouts in Europe, North America, and Australia. It concludes that a comprehensive, integrated policy response is required to avoid preventable large-scale blackouts in the future.

Alcohol-induced blackout as a criminal defense or mitigating factor: an evidence-based review and admissibility as scientific evidence.

Science.gov (United States)

Pressman, Mark R; Caudill, David S

2013-07-01

Alcohol-related amnesia--alcohol blackout--is a common claim of criminal defendants. The generally held belief is that during an alcohol blackout, other cognitive functioning is severely impaired or absent. The presentation of alcohol blackout as scientific evidence in court requires that the science meets legal reliability standards (Frye, FRE702/Daubert). To determine whether "alcohol blackout" meets these standards, an evidence-based analysis of published scientific studies was conducted. A total of 26 empirical studies were identified including nine in which an alcohol blackout was induced and directly observed. No objective or scientific method to verify the presence of an alcoholic blackout while it is occurring or to confirm its presence retrospectively was identified. Only short-term memory is impaired and other cognitive functions--planning, attention, and social skills--are not impaired. Alcoholic blackouts would not appear to meet standards for scientific evidence and should not be admissible. © 2013 American Academy of Forensic Sciences.

Reactor coolant pump shaft seal behavior during blackout conditions

International Nuclear Information System (INIS)

Mings, W.J.

1985-01-01

The United States Nuclear Regulatory Commission has classified the problem of reactor coolant pump seal failures as an unresolved safety issue. This decision was made in large part due to experimental results obtained from a research program developed to study shaft seal performance during station blackout and reported in this paper. Testing and analysis indicated a potential for pump seal failure under postulated blackout conditions leading to a loss of primary coolant with a concomitant danger of core uncovery. The work to date has not answered all the concerns regarding shaft seal failure but it has helped scope the problem and focus future research needed to completely resolve this issue

Control and prediction for blackouts caused by frequency collapse in smart grids.

Science.gov (United States)

Wang, Chengwei; Grebogi, Celso; Baptista, Murilo S

2016-09-01

The electric power system is one of the cornerstones of modern society. One of its most serious malfunctions is the blackout, a catastrophic event that may disrupt a substantial portion of the system, playing havoc to human life and causing great economic losses. Thus, understanding the mechanisms leading to blackouts and creating a reliable and resilient power grid has been a major issue, attracting the attention of scientists, engineers, and stakeholders. In this paper, we study the blackout problem in power grids by considering a practical phase-oscillator model. This model allows one to simultaneously consider different types of power sources (e.g., traditional AC power plants and renewable power sources connected by DC/AC inverters) and different types of loads (e.g., consumers connected to distribution networks and consumers directly connected to power plants). We propose two new control strategies based on our model, one for traditional power grids and another one for smart grids. The control strategies show the efficient function of the fast-response energy storage systems in preventing and predicting blackouts in smart grids. This work provides innovative ideas which help us to build up a robuster and more economic smart power system.

Estimation of station blackout frequency in FBTR

International Nuclear Information System (INIS)

Senthil Kumar, C.; John Arul, A.; Anandapadmanaban, B.; Marimuthu, S.; Singh, Om Pal

2002-01-01

Full text: In this paper, station blackout (SBO) frequency is computed as a function of blackout duration based on available data in FBTR. The frequency of loss of offsite power (LOSP) at FBTR is found to be 5.2/year. The data on the LOSP and failure data on feeders and transformers at FBTR are used to arrive at the frequency of LOSP as a function of down time for single feeder and double feeder cases. The non-recovery probability of offsite power failure with time is well represented by exponential distribution for times less than 2 h and Weibull distribution beyond 2 h. The unavailability of onsite emergency power supply was evaluated using Markov method and fault tree method and is 1.0E-2 and 3.34E-3 respectively. Using the above data and the non-recovery probability of DG, frequency of SBO at FBTR with single feeder and double feeder cases, for different time durations were evaluated. It is found that the frequency of station blackout at FBTR with double feeder computed using Markov method is ∼10 -4 /yr for 11 h and 10 -5 /yr for 19 h duration. With one feeder out of service the SBO frequency is more by a factor 5. Sensitivity study done with respect to DG repair time and common cause failure indicate that the results in the magnitude of SBO could be uncertain by a factor of ten. The uncertainty is less for shorter SBO duration and more for longer SBO duration

Implications of Extension of Station Blackout Cooping Capability on Nuclear Power Plant Safety

International Nuclear Information System (INIS)

Volkanovski, Andrija

2015-01-01

The safety of the nuclear power plant depends on the availability of the continuous and reliable sources of electrical energy during all modes of operation of the plant. The station blackout corresponds to a total loss of all alternate current (AC) power as a result of complete failure of both offsite and on-site AC power sources. The electricity for the essential systems during station blackout is provided from the batteries installed in the nuclear power plant. The results of the probabilistic safety assessment show that station blackout is one of the main and frequently the dominant contributor to the core damage frequency. Results of the analysis of the implications of the strengthening of the SBO mitigation capability on safety of the NPP will be presented. The assessment is done with state-of-art deterministic and probabilistic methods and tolls with application on reference models of nuclear power plants. The safety analysis is done on reference model of the nuclear power plant. Obtained results show large decrease of the core damage frequency with strengthening of the station blackout mitigation capability. The time extension of blackout coping capability results in the delay of the core heat up for at least the extension time interval. Availability and operation of the steam driven auxiliary feedwater system maintains core integrity up to 72 h after the successful shutdown, even in the presence of the reactor coolant pumps seal leakage. The largest weighted decrease of the core damage frequency considering the costs for the modification is obtained for the modification resulting in extension of the station blackout coping capability. The importance of the common cause failures of the emergency diesel generators for the obtained decrease of the core damage frequency and overall safety of the plant is identified in the obtained results. (authors)

Acute alcohol effects on narrative recall and contextual memory: an examination of fragmentary blackouts.

Science.gov (United States)

Wetherill, Reagan R; Fromme, Kim

2011-08-01

The present study examined the effects of alcohol consumption on narrative recall and contextual memory among individuals with and without a history of fragmentary blackouts in an attempt to better understand why some individuals experience alcohol-induced memory impairments whereas others do not, even at comparable blood alcohol concentrations (BACs). Standardized beverage (alcohol and no alcohol) administration procedures and neuropsychological assessments measured narrative recall and context memory performance before and after alcohol consumption in individuals with (n=44) and without (n=44) a history of fragmentary blackouts. Findings indicate that acute alcohol intoxication led to impairments in free recall, but not next-day cued recall. Further, participants showed similar memory performance when sober, but individuals who consumed alcohol and had a positive history of fragmentary blackouts showed greater contextual memory impairments than those who had not previously experienced a fragmentary blackout. Thus, it appears that some individuals may have an inherent vulnerability to alcohol-induced memory impairments due to alcohol's effects on contextual memory processes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Safety aspects of station blackout at nuclear power plants

International Nuclear Information System (INIS)

1985-03-01

The principal focus of this report is on existing light water reactor nuclear power plants. However, many of the considerations discussed herein can be equally applied to new plants, i.e. those not yet in construction. This report is organized to provide a description of design and procedural factors which safety assessments and reviews of operating experience have shown to be important. These are divided into the off-site power system, the on-site AC power systems and alternate (or nearby) sources of power. The latter may be used in the unlikely event that both normal off-site and on-site sources fail. It must be emphasized that first priority should be placed on designing and maintaining high reliability of both the off-site and on-site AC power systems. This basic concept also applies to the capabilities for restoring power sources which failed and making use of all available alternative and nearby power sources during an emergency, to restore AC power in a prompt manner. Discussions on these aspects are provided in chapters 2 and 3 of this report. Because the expected event frequency and associated confidence in such estimations of station blackout are uncertain, preparations should be made to deal with a station blackout. The nature of those preparations, whether they be optimizing emergency procedures to use existing equipment, modifying this equipment to enhance capabilities, or adding new components or systems to cope with station blackout, must be made in light of plant-specific assessments and regulatory safety philosophies/requirements. Discussions on these matters are provided in chapter 4. General and specific conclusions and recommendations are provided in chapter 5. Appendix A provides a description of several case studies on station blackout and loss of off-site power. Abstracts of papers and presentations are provided in Appendix B with authors and affiliations identified to facilitate personal contact. The References and Bibliography contain a

Accident Analysis of Chinese CPR1000 in Response to Station Blackout

Energy Technology Data Exchange (ETDEWEB)

Kim, Juyoul [FNC Technology Co., Yongin (Korea, Republic of); Cilliers, Anthonie [North-West University, Potchefstroom (South Africa)

2016-10-15

Stress tests required evaluation of the consequences of loss of safety functions from any initiating event (e.g., earthquake or flooding) causing loss of electrical power, including station blackout (SBO). The SBO scenario involves a loss of offsite power, failure of the redundant emergency diesel generators, failure of alternate current (AC) power restoration and the eventual degradation of the reactor coolant pump (RCP) seals resulting in a long term loss of coolant. Using PCTRAN/CPR1000, this study analyses the station blackout on a Chinese CPR1000 which is the most representative type reactor in terms of number of reactors, operating period, power capacity and geological distance from Korean Peninsula. Both the physical effects of the accidents as well as the releases of radioisotopes are calculated and discussed. Station blackout simulation was conducted in this study. The resulting effects seen are consistent with other stress test station blackout tests used utilizing licensed simulation codes. An exact comparison is however not possible as the plants on which the simulations was done vary greatly and the limitations of availability to Chinese FSAR. PCTRAN/CPR1000 is an extremely useful simulation package that provides engineers and scientists very accurate feedback to how a nuclear power plant would react as a whole under various plant conditions. It is able to do this extremely fast as well. As a training tool PCTRAN/CPR1000 provides hands-on experience with many of the primary plant operations and develops an intuitive understanding of the plant.

Comparison of static model and dynamic model for the evaluation of station blackout sequences

International Nuclear Information System (INIS)

Lee, Kwang-Nam; Kang, Sun-Koo; Hong, Sung-Yull.

1992-01-01

Station blackout is one of major contributors to the core damage frequency (CDF) in many PSA studies. Since station blackout sequence exhibits dynamic features, accurate calculation of CDF for the station blackout sequence is not possible with event tree/fault tree (ET/FT) method. Although the integral method can determine accurate CDF, it is time consuming and is difficult to evaluate various alternative AC source configuration and sensitivities. In this study, a comparison is made between static model and dynamic model and a new methodology which combines static model and dynamic model is provided for the accurate quantification of CDF and evaluation of improvement alternatives. Results of several case studies show that accurate calculation of CDF is possible by introducing equivalent mission time. (author)

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.

Comparative analysis of station blackout accident progression in typical PWR, BWR, and PHWR

International Nuclear Information System (INIS)

Park, Soo Young; Ahn, Kwang Il

2012-01-01

Since the crisis at the Fukushima plants, severe accident progression during a station blackout accident in nuclear power plants is recognized as a very important area for accident management and emergency planning. The purpose of this study is to investigate the comparative characteristics of anticipated severe accident progression among the three typical types of nuclear reactors. A station blackout scenario, where all off-site power is lost and the diesel generators fail, is simulated as an initiating event of a severe accident sequence. In this study a comparative analysis was performed for typical pressurized water reactor (PWR), boiling water reactor (BWR), and pressurized heavy water reactor (PHWR). The study includes the summarization of design differences that would impact severe accident progressions, thermal hydraulic/severe accident phenomenological analysis during a station blackout initiated-severe accident; and an investigation of the core damage process, both within the reactor vessel before it fails and in the containment afterwards, and the resultant impact on the containment.

Reactor coolant pump shaft seal behavior during station blackout

International Nuclear Information System (INIS)

Kittmer, C.A.; Wensel, R.G.; Rhodes, D.B.; Metcalfe, R.; Cotnam, B.M.; Gentili, H.; Mings, W.J.

1985-04-01

A testing program designed to provide fundamental information pertaining to the behavior of reactor coolant pump (RCP) shaft seals during a postulated nuclear power plant station blackout has been completed. One seal assembly, utilizing both hydrodynamic and hydrostatic types of seals, was modeled and tested. Extrusion tests were conducted to determine if seal materials could withstand predicted temperatures and pressures. A taper-face seal model was tested for seal stability under conditions when leaking water flashes to steam across the seal face. Test information was then used as the basis for a station blackout analysis. Test results indicate a potential problem with an elastomer material used for O-rings by a pump vendor; that vendor is considering a change in material specification. Test results also indicate a need for further research on the generic issue of RCP seal integrity and its possible consideration for designation as an unresolved safety issue

Station blackout core damage frequency in an advanced nuclear reactor

International Nuclear Information System (INIS)

Carvalho, Luiz Sergio de

2004-01-01

Even though nuclear reactors are provided with protection systems so that they can be automatically shut down in the event of a station blackout, the consequences of this event can be severe. This is because many safety systems that are needed for removing residual heat from the core and for maintaining containment integrity, in the majority of the nuclear power plants, are AC dependent. In order to minimize core damage frequency, advanced reactor concepts are being developed with safety systems that use natural forces. This work shows an improvement in the safety of a small nuclear power reactor provided by a passive core residual heat removal system. Station blackout core melt frequencies, with and without this system, are both calculated. The results are also compared with available data in the literature. (author)

Evaluating the effect of a campus-wide social norms marketing intervention on alcohol-use perceptions, consumption, and blackouts.

Science.gov (United States)

Su, Jinni; Hancock, Linda; Wattenmaker McGann, Amanda; Alshagra, Mariam; Ericson, Rhianna; Niazi, Zackaria; Dick, Danielle M; Adkins, Amy

2018-04-01

To evaluate the effect of a campus-wide social norms marketing intervention on alcohol-use perceptions, consumption, and blackouts at a large, urban, public university. 4,172 college students (1,208 freshmen, 1,159 sophomores, 953 juniors, and 852 seniors) who completed surveys in Spring 2015 for the Spit for Science Study, a longitudinal study of students' substance use and emotional health. Participants were e-mailed an online survey that queried campaign readership, perception of peer alcohol use, alcohol consumption, frequency of consumption, and frequency of blackouts. Associations between variables were evaluated using path analysis. We found that campaign readership was associated with more accurate perceptions of peer alcohol use, which, in turn, was associated with self-reported lower number of drinks per sitting and experiencing fewer blackouts. This evaluation supports the use of social norms marketing as a population-level intervention to correct alcohol-use misperceptions and reduce blackouts.

Probabilistic assessment of the Juragua NPP response under Station Blackout conditions

International Nuclear Information System (INIS)

Valhuerdi Debesa, C.; Vilaragut Llanes, J.J.

1996-01-01

Assessment of the NPP response under SBO (station Blackout) conditions is a current safety issue of special interest, In the case of Juragua NPP, the safety assessment related to this topic is very important, taking into account the peculiarities of the Cuban Electro energetic System: small and long island, without possibilities of conexion beyond its borders and under the incidence of tropical phenomena In this papers a preliminary evaluation is presented of the potential incidence of Station Blackout conditions for Juragua NPP. the importance of this sort of events for the safety of the plant is evaluated, the factors which condition it are identified and measures for its prevention or recovering the normal situation if such an event takes place are proposed

Sustainability from the Occurrence of Critical Dynamic Power System Blackout Determined by Using the Stochastic Event Tree Technique

Directory of Open Access Journals (Sweden)

Muhammad Murtadha Othman

2017-06-01

Full Text Available With the advent of advanced technology in smart grid, the implementation of renewable energy in a stressed and complicated power system operation, aggravated by a competitive electricity market and critical system contingencies, this will inflict higher probabilities of the occurrence of a severe dynamic power system blackout. This paper presents the proposed stochastic event tree technique used to assess the sustainability against the occurrence of dynamic power system blackout emanating from implication of critical system contingencies such as the rapid increase in total loading condition and sensitive initial transmission line tripping. An extensive analysis of dynamic power system blackout has been carried out in a case study of the following power systems: IEEE RTS-79 and IEEE RTS-96. The findings have shown that the total loading conditions and sensitive transmission lines need to be given full attention by the utility to prevent the occurrence of dynamic power system blackout.

Station blackout with reactor coolant pump seal leakage

International Nuclear Information System (INIS)

Evinay, A.

1993-01-01

The U.S. Nuclear Regulatory Commission (NRC) amended its regulations in 10CFR50 with the addition of a new section, 50.63, open-quotes Loss of All Alternating Current Power.close quotes The objective of these requirements is to ensure that all nuclear plants have the capability to withstand a station blackout (SBO) and maintain adequate reactor core cooling and containment integrity for a specified period of time. The NRC also issued Regulatory Guide (RG) 1.155, open-quotes Station Blackout,close quotes to provide guidance for meeting the requirements of 10CFR50.63. Concurrent with RG-1.155, the Nuclear Utility Management and Resources Council (NUMARC) has developed NUMARC 87-00 to address SBO-coping duration and capabilities at light water reactors. Licensees are required to submit a topical report based on NUMARC 87-00 guidelines, to demonstrate compliance with the SBO rule. One of the key compliance criteria is the ability of the plant to maintain adequate reactor coolant system (RCS) inventory to ensure core cooling for the required coping duration, assuming a leak rate of 25 gal/min per reactor coolant pump (RCP) seal in addition to technical specification (TS) leak rate

Cognitive Blackouts in Mild Cognitive Impairment and Alzheimer’s Dementia

Directory of Open Access Journals (Sweden)

Georg Adler

2018-02-01

Full Text Available Background: Cognitive blackouts, e.g. moments of amnesia, disorientation, or perplexity may be an early sign of incipient Alzheimer’s dementia (AD. A short questionnaire, the checklist for cognitive blackouts (CCB, was evaluated cross-sectionally in users of a memory clinic. Methods: The CCB was performed in 130 subjects, who further underwent a neuropsychological and clinical examination. Subjective memory impairment and depressive symptoms were assessed. Differences in the CCB score between diagnostic groups and relationships with cognitive performance, depression, and subjective memory impairment were analyzed. Results: The CCB score was increased in mild cognitive impairment of the amnestic type or mild AD and correctly predicted 69.2% of the respective subjects. It was negatively correlated with cognitive performance, positively correlated with depressive symptoms, and substantially increased in subjects who estimated their memory poorer than that of other persons of their age. Discussion: The CCB may be a helpful screening tool for the early recognition of AD.

The AP1000R nuclear power plant innovative features for extended station blackout mitigation

International Nuclear Information System (INIS)

Vereb, F.; Winters, J.; Schulz, T.; Cummins, E.; Oriani, L.

2012-01-01

Station Blackout (SBO) is defined as 'a condition wherein a nuclear power plant sustains a loss of all offsite electric power system concurrent with turbine trip and unavailability of all onsite emergency alternating current (AC) power system. Station blackout does not include the loss of available AC power to buses fed by station batteries through inverters or by alternate AC sources as defined in this section, nor does it assume a concurrent single failure or design basis accident...' in accordance with Reference 1. In this paper, the innovative features of the AP1000 plant design are described with their operation in the scenario of an extended station blackout event. General operation of the passive safety systems are described as well as the unique features which allow the AP1000 plant to cope for at least 7 days during station blackout. Points of emphasis will include: - Passive safety system operation during SBO - 'Fail-safe' nature of key passive safety system valves; automatically places the valve in a conservatively safe alignment even in case of multiple failures in all power supply systems, including normal AC and battery backup - Passive Spent Fuel Pool cooling and makeup water supply during SBO - Robustness of AP1000 plant due to the location of key systems, structures and components required for Safe Shutdown - Diverse means of supplying makeup water to the Passive Containment Cooling System (PCS) and the Spent Fuel Pool (SFP) through use of an engineered, safety-related piping interface and portable equipment, as well as with permanently installed onsite ancillary equipment. (authors)

Europe's electrical vulnerability geography : historical interpretations of the 2006 'European blackout'

NARCIS (Netherlands)

Vleuten, van der E.B.A.; Lagendijk, V.C.

2009-01-01

The so-called "European Blackout" of 4 November 2006 counts as a key example of present day transnational infrastructure vulnerability and an important reference in current debates on transnational electricity infrastructure governance. This is best examplified by the debate itself, where proponents

Transnational infrastructure vulnerability : the historical shaping of the 2006 European 'blackout'

NARCIS (Netherlands)

Vleuten, van der E.B.A.; Lagendijk, V.C.

2010-01-01

The "European Blackout" of 4 November 2006 is a key reference in current debates on transnational electricity infrastructure vulnerability and governance. Several commentators have observed that to understand what happened, one must look at history. Our paper answers this call and demonstrates how

Investigation of plasma–surface interaction effects on pulsed electrostatic manipulation for reentry blackout alleviation

International Nuclear Information System (INIS)

Krishnamoorthy, S; Close, S

2017-01-01

The reentry blackout phenomenon affects most spacecraft entering a dense planetary atmosphere from space, due to the presence of a plasma layer that surrounds the spacecraft. This plasma layer is created by ionization of ambient air due to shock and frictional heating, and in some cases is further enhanced due to contamination by ablation products. This layer causes a strong attenuation of incoming and outgoing electromagnetic waves including those used for command and control, communication and telemetry over a period referred to as the ‘blackout period’. The blackout period may last up to several minutes and is a major contributor to the landing error ellipse at best, and a serious safety hazard in the worst case, especially in the context of human spaceflight. In this work, we present a possible method for alleviation of reentry blackout using electronegative DC pulses applied from insulated electrodes on the reentry vehicle’s surface. We study the reentry plasma’s interaction with a DC pulse using a particle-in-cell (PIC) model. Detailed models of plasma–insulator interaction are included in our simulations. The absorption and scattering of ions and electrons at the plasma–dielectric interface are taken into account. Secondary emission from the insulating surface is also considered, and its implications on various design issues is studied. Furthermore, we explore the effect of changing the applied voltage and the impact of surface physics on the creation and stabilization of communication windows. The primary aim of this analysis is to examine the possibility of restoring L- and S-band communication from the spacecraft to a ground station. Our results provide insight into the effect of key design variables on the response of the plasma to the applied voltage pulse. Simulations show the creation of pockets where electron density in the plasma layer is reduced three orders of magnitude or more in the vicinity of the electrodes. These pockets extend to

Regulatory analysis for the resolution of Unresolved Safety Issue A-44, Station Blackout. Draft report

International Nuclear Information System (INIS)

Rubin, A.M.

1986-01-01

''Station Blackout'' is the complete loss of alternating current (ac) electric power to the essential and nonessential buses in a nuclear power plant; it results when both offsite power and the onsite emergency ac power systems are unavailable. Because many safety systems required for reactor core decay heat removal and containment heat removal depend on ac power, the consequences of a station blackout could be severe. Because of the concern about the frequency of loss of offsite power, the number of failures of emergency diesel generators, and the potentially severe consequences of a loss of all ac power, ''Station Blackout'' was designated as Unresolved Safety Issue (USI) A-44. This report presents the regulatory analysis for USI A-44. It includes: (1) a summary of the issue, (2) the proposed technical resolution, (3) alternative resolutions considered by the Nuclear Regulatory Commission (NRC) staff, (4) an assessment of the benefits and costs of the recommended resolution, (5) the decision rationale, and (6) the relationship between USI A-44 and other NRC programs and requirements

The AP1000{sup R} nuclear power plant innovative features for extended station blackout mitigation

Energy Technology Data Exchange (ETDEWEB)

Vereb, F.; Winters, J.; Schulz, T.; Cummins, E.; Oriani, L. [Westinghouse Electric Company LLC, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

2012-07-01

Station Blackout (SBO) is defined as 'a condition wherein a nuclear power plant sustains a loss of all offsite electric power system concurrent with turbine trip and unavailability of all onsite emergency alternating current (AC) power system. Station blackout does not include the loss of available AC power to buses fed by station batteries through inverters or by alternate AC sources as defined in this section, nor does it assume a concurrent single failure or design basis accident...' in accordance with Reference 1. In this paper, the innovative features of the AP1000 plant design are described with their operation in the scenario of an extended station blackout event. General operation of the passive safety systems are described as well as the unique features which allow the AP1000 plant to cope for at least 7 days during station blackout. Points of emphasis will include: - Passive safety system operation during SBO - 'Fail-safe' nature of key passive safety system valves; automatically places the valve in a conservatively safe alignment even in case of multiple failures in all power supply systems, including normal AC and battery backup - Passive Spent Fuel Pool cooling and makeup water supply during SBO - Robustness of AP1000 plant due to the location of key systems, structures and components required for Safe Shutdown - Diverse means of supplying makeup water to the Passive Containment Cooling System (PCS) and the Spent Fuel Pool (SFP) through use of an engineered, safety-related piping interface and portable equipment, as well as with permanently installed onsite ancillary equipment. (authors)

Pressurized-water-reactor station blackout

International Nuclear Information System (INIS)

Dobbe, C.A.

1983-01-01

The purpose of the Severe Accident Sequence Analysis (SASA) Program was to investigate accident scenarios beyond the design basis. The primary objective of SASA was to analyze nuclear plant transients that could lead to partial or total core melt and evaluate potential mitigating actions. The following summarizes the pressurized water reactor (PWR) SASA effort at the Idaho National Engineering Laboratory (INEL). The INEL is presently evaluating Unresolved Safety Issue A-44 - Station Blackout from initiation of the transient to core uncovery. The balance of the analysis from core uncovery until fission product release is being performed at Sandia National Laboratory (SNL). The current analyses involve the Bellefonte Nuclear Steam Supply System (NSSS), a Babcock and Wilcox (B and W) 205 Fuel Assembly (205-FA) raised loop design to be operated by the Tennessee Valley Authority

Station blackout calculations for Peach Bottom

International Nuclear Information System (INIS)

Hodge, S.A.

1985-01-01

A calculational procedure for the Station Blackout Severe Accident Sequence at Browns Ferry Unit One has been repeated with plant-specific application to one of the Peach Bottom Units. The only changes required in code input are with regard to the primary continment concrete, the existence of sprays in the secondary containment, and the size of the refueling bay. Combustible gas mole fractions in the secondary containment of each plant during the accident sequence are determined. It is demonstrated why the current state-of-the-art corium/concrete interaction code is inadequate for application to the study of Severe Accident Sequences in plants with the BWR MK I or MK II containment design

Review of Leading Approaches for Mitigating Hypersonic Vehicle Communications Blackout and a Method of Ceramic Particulate Injection Via Cathode Spot Arcs for Blackout Mitigation

Science.gov (United States)

Gillman, Eric D.; Foster, John E.; Blankson, Isaiah M.

2010-01-01

Vehicles flying at hypersonic velocities within the atmosphere become enveloped in a "plasma sheath" that prevents radio communication, telemetry, and most importantly, GPS signal reception for navigation. This radio "blackout" period has been a problem since the dawn of the manned space program and was an especially significant hindrance during the days of the Apollo missions. An appropriate mitigation method must allow for spacecraft to ground control and ground control to spacecraft communications through the reentry plasma sheath. Many mitigation techniques have been proposed, including but not limited to, aerodynamic shaping, magnetic windows, and liquid injection. The research performed on these mitigation techniques over the years will be reviewed and summarized, along with the advantages and obstacles that each technique will need to overcome to be practically implemented. A unique approach for mitigating the blackout communications problem is presented herein along with research results associated with this method. The novel method involves the injection of ceramic metal-oxide particulate into a simulated reentry plasma to quench the reentry plasma. Injection of the solid ceramic particulates is achieved by entrainment within induced, energetic cathode spot flows.

Analysis of a station blackout transient at the Kori units 3/4

International Nuclear Information System (INIS)

Bang, Young Seok; Kim, Hho Jung

1992-01-01

A transient analysis of station blackout accident is performed to evaluate the plant specific capability to cope with the accident at the Kori Units 3/4. The RELAP5/MOD3/5m5 code and full three loop modelling scheme are used in the calculation. The leak flow from reactor coolant system due to a failure of reactor coolant pump seal following the accident is assumed to be 25 gpm and the turbine driven aux feedwater unavailable. As a result, it is found that no core uncovery occurs in the plant until 7100 sec following a station blackout, the steam generator has a decay heat removal capability until 3100 sec, and the natural circulation over the reactor coolant loop until the complete loop seal voiding are observed. And the Nuclear Plant Analyzer is used and found to be effective in improving the phenomenological understanding on the accident

Emergency makeup of nuclear steam generators in blackout conditions

International Nuclear Information System (INIS)

Korolev, A.V.; Derevyanko, O.V.

2014-01-01

The paper describes an original solution for using steam energy to organize makeup of NPP steam generators in blackout conditions. The proposed solution combines a disk friction turbine and an axial turbine in a single housing to provide a high overall technical effect enabling the replenishment of nuclear steam generators with steam using the pump turbine drive assembly. The application of the design is analyzed and its efficiency and feasibility are shown

Application of a steam injector for passive emergency core cooling during a station blackout

International Nuclear Information System (INIS)

Heinze, D.; Behnke, L.; Schulenberg, T.

2012-01-01

One of the basic protection targets of reactor safety is the safe heat removal during normal operation but also following shut-down. Since the reactor accident in Fukushima an optimization of the plant robustness in case of beyond-design accident is performed. Special attention is given to the increase of time available for starting appropriate measures for emergency core cooling in case of a station blackout. The state-of the art in engineering and research is presented. Investigations on the applicability of a steam injector for passive emergency core cooling during a station blackout in BWR-type reactors have progressed, experiments on dynamic behavior of the injector are described. A precise design with respect to the thermal hydraulic boundary conditions has been performed.

Station blackout and public confidence: a cautionary tale

International Nuclear Information System (INIS)

Cave, L.

1990-01-01

The recent ''station blackout'' (ie loss of on-site and off-site AC power) incidents at the Vogtle PWR in the US and Hinkley Point B AGR in the Uk have led to further public concern about the safety of nuclear power, even though in each case the actual increase in the chance of an accident leading to a release of radioactivity to the environment was negligible. The industry may be wise to invest precautionary measures to reduce the frequency of such incidents and to increase public confidence. (author)

Station blackout transient at the Browns Ferry Unit 1 Plant: a severe accident sequence analysis (SASA) program study

International Nuclear Information System (INIS)

Schultz, R.R.

1982-01-01

Operating plant transients are of great interest for many reasons, not the least of which is the potential for a mild transient to degenerate to a severe transient yielding core damage. Using the Browns Ferry (BF) Unit-1 plant as a basis of study, the station blackout sequence was investigated by the Severe Accident Sequence Analysis (SASA) Program in support of the Nuclear Regulatory Commission's Unresolved Safety Issue A-44: Station Blackout. A station blackout transient occurs when the plant's AC power from a comemrcial power grid is lost and cannot be restored by the diesel generators. Under normal operating conditions, f a loss of offsite power (LOSP) occurs [i.e., a complete severance of the BF plants from the Tennessee Valley Authority (TVA) power grid], the eight diesel generators at the three BF units would quickly start and power the emergency AC buses. Of the eight diesel generators, only six are needed to safely shut down all three units. Examination of BF-specific data show that LOSP frequency is low at Unit 1. The station blackout frequency is even lower (5.7 x 10 - 4 events per year) and hinges on whether the diesel generators start. The frequency of diesel generator failure is dictated in large measure by the emergency equipment cooling water (EECW) system that cools the diesel generators

Performance Evaluation of Target Detection with a Near-Space Vehicle-Borne Radar in Blackout Condition.

Science.gov (United States)

Li, Yanpeng; Li, Xiang; Wang, Hongqiang; Deng, Bin; Qin, Yuliang

2016-01-06

Radar is a very important sensor in surveillance applications. Near-space vehicle-borne radar (NSVBR) is a novel installation of a radar system, which offers many benefits, like being highly suited to the remote sensing of extremely large areas, having a rapidly deployable capability and having low vulnerability to electronic countermeasures. Unfortunately, a target detection challenge arises because of complicated scenarios, such as nuclear blackout, rain attenuation, etc. In these cases, extra care is needed to evaluate the detection performance in blackout situations, since this a classical problem along with the application of an NSVBR. However, the existing evaluation measures are the probability of detection and the receiver operating curve (ROC), which cannot offer detailed information in such a complicated application. This work focuses on such requirements. We first investigate the effect of blackout on an electromagnetic wave. Performance evaluation indexes are then built: three evaluation indexes on the detection capability and two evaluation indexes on the robustness of the detection process. Simulation results show that the proposed measure will offer information on the detailed performance of detection. These measures are therefore very useful in detecting the target of interest in a remote sensing system and are helpful for both the NSVBR designers and users.

PSB-VVER experimental and analytical investigation of station blackout accident in VVER-1000

Energy Technology Data Exchange (ETDEWEB)

Lipatov, I.A.; Kapustin, A.V.; Nikonov, S.M.; Rovnov, A.A.; Basov, A.V. [Electrogorsk Research and Engineering Centre (EREC), Moscow Region (Russian Federation); Elkin, I.V. [NSI RRC, Kurchatov Institute, Moscow (Russian Federation)

2007-07-01

In November 2003, an experiment simulating station blackout accident was carried out in the PSB-VVER integral test facility at the Electrogorsk Research and Engineering Centre (Russia). The purpose of the experiment was to provide missing data for code validation as well as to investigate the VVER thermohydraulics in the blackout conditions. The experiment covers a wide range of phenomena relating not only to transients but also to small break loss-of-coolant accidents. The data gained in the test has been used to assess the RELAP5/MOD3.3 code. In this paper, a special attention has been paid to the code assessment regarding the mixture level and entrainment in steam generator secondary side. The analysis of the recorded transient has shown that the calculation of the heat transfer on the secondary side of steam generators is very sensitive to the steam generator nodalization. (authors)

An electromagnetic method for removing the communication blackout with a space vehicle upon re-entry into the atmosphere

Science.gov (United States)

Cheng, Jianjun; Jin, Ke; Kou, Yong; Hu, Ruifeng; Zheng, Xiaojing

2017-03-01

When a hypersonic vehicle travels in the Earth and Mars atmosphere, the surface of the vehicle is surrounded by a plasma layer, which is an envelope of ionized air, created from the compression and heat of the atmosphere by the shock wave. The vehicles will lose contact with ground stations known as the reentry communication blackout. Based on the magnetohydrodynamic framework and electromagnetic wave propagation theory, an analytical model is proposed to describe the effect of the effectiveness of electromagnetic mitigation scheme on removing the reentry communication blackout. C and Global Positioning System (GPS) bands, two commonly used radio bands for communication, are taken as the cases to discuss the effectiveness of the electromagnetic field mitigation scheme. The results show that the electron density near the antenna of vehicles can be reduced by the electromagnetic field, and the required external magnetic field strength is far below the one in the magnetic window method. The directions of the external electric field and magnetic field have a significant impact on the effectiveness of the mitigation scheme. Furthermore, the effect of electron collisions on the required applied electromagnetic field is discussed, and the result indicates that electron collisions are a key factor to analyze the electromagnetic mitigation scheme. Finally, the feasible regions of the applied electromagnetic field for eliminating blackout are given. These investigations could have a significant benefit on the design and optimization of electromagnetic mitigation scheme for the blackout problem.

Case study on the use of PSA methods: Station blackout risk at Millstone Unit 3

International Nuclear Information System (INIS)

1991-04-01

In Westinghouse pressurized water reactors, severe accidents sequences resulting from station blackout have been recognized to be significant contributors to risk of core damage and public consequences. To properly quantify the risk of station blackout it is necessary to consider all possible types of core damage scenarios. Having obtained an accurate representation of the types of core damage scenarios involved specific areas of vulnerability can be pinpointed for further improvement. In performing this analysis it was decided to use time dependent probabilistic safety assessment method to provide a more realistic treatment of time dependent failure and recovery. Overview of the analysis, calculation procedures and methods, interpretation of the results are discussed. Peer review process is described. 13 refs, 19 figs

High-Tech, Low-Tech, No-Tech: Communications Strategies During Blackouts

Science.gov (United States)

2013-12-01

straight-line “ derecho ”1 windstorms hit the mid-Atlantic region of the United States. In the National Capital Region (NCR), many residents lost...flooding (Grand Forks, North Dakota, 1997), rolling blackouts (California, 2001), multi-state power outage (Ohio and seven other 1 “ Derecho ” is a...flawlessly throughout the 2012 “super- derecho ”20 storm event.21 During its 2012 typhoon, the government of the Philippines used Twitter to

Observing power blackouts from space - A disaster related study

Science.gov (United States)

Aubrecht, C.; Elvidge, C. D.; Ziskin, D.; Baugh, K. E.; Tuttle, B.; Erwin, E.; Kerle, N.

2009-04-01

In case of emergency disaster managers worldwide require immediate information on affected areas and estimations of the number of affected people. Natural disasters such as earthquakes, hurricanes, tornados, wind and ice storms often involve failures in the electrical power generation system and grid. Near real time identification of power blackouts gives a first impression of the area affected by the event (Elvidge et al. 2007), which can subsequently be linked to population estimations. Power blackouts disrupt societal activities and compound the difficulties associated with search and rescue, clean up, and the provision of food and other supplies following a disastrous event. Locations and spatial extents of power blackouts are key considerations in planning and execution of the primary disaster missions of emergency management organizations. To date only one satellite data source has been used successfully for the detection of power blackouts. Operated by NOAA's National Geophysical Data Center (NGDC) the U.S. Air Force Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) offers a unique capability to observe lights present at the Earth's surface at night. Including a pair of visible and thermal spectral bands and originally designed to detect moonlit clouds, this sensor enables mapping of lights from cities and towns, gas flares and offshore platforms, fires, and heavily lit fishing boats. The low light imaging of the OLS is accomplished using a photomultiplier tube (PMT) which intensifies the visible band signal at night. With 14 orbits collected per day and a 3.000 km swath width, each OLS is capable of collecting a complete set of images of the Earth every 24 hours. NGDC runs the long-term archive for OLS data with the digital version extending back to 1992. OLS data is received by NGDC in near real time (1-2 hours from acquisition) and subscription based services for the near real time data are provided for users all over the

The 4 november 2006 blackout: an outage of 'technical' democracy?

International Nuclear Information System (INIS)

Leteurtrois, J.P.

2007-01-01

With its power plants and exportation of electricity to neighboring lands, France imagined that it was sheltered from blackouts. But in the autumn of 2006, five million French households were deprived of electricity due to an error by a German operator. What to think of this? The internationalization of the electricity market, though useful to consumers, should not mean deregulation or the relinquishment of rules and regulations to power companies. Supervision of the grid must be reinforced on behalf of all European users of electricity. (author)

Uncertainties in source term estimates for a station blackout accident in a BWR with Mark I containment

International Nuclear Information System (INIS)

Lee, M.; Cazzoli, E.; Liu, Y.; Davis, R.; Nourbakhsh, H.; Schmidt, E.; Unwin, S.; Khatib-Rahbar, M.

1988-01-01

In this paper, attention is limited to a single accident progression sequence, namly a station blackout accident in a BWR with a Mark I containment building. Identified as an important accident in the draft version of NUREG-1150 a station blackout involves loss of both off-site power and dc power resulting in failure of the diesels to start and in the unavailability of the high pressure injection and core isolation cooling systems. This paper illustrates the calculated uncertainties (Probability Density Functions) associated with the radiological releases into the environment for the nine fission product groups at 10 hours following the initiation of core-concrete interactions. Also shown are the results ofthe STCP base case simulation. 5 refs., 1 fig., 1 tab

Design Provisions for Station Blackout at Nuclear Power Plants

International Nuclear Information System (INIS)

Duchac, Alexander

2015-01-01

A station blackout (SBO) is generally known as 'a plant condition with complete loss of all alternating current (AC) power from off-site sources, from the main generator and from standby AC power sources important to safety to the essential and nonessential switchgear buses. Direct current (DC) power supplies and un-interruptible AC power supplies may be available as long as batteries can supply the loads. Alternate AC power supplies are available'. A draft Safety Guide DS 430 'Design of Electrical Power Systems for Nuclear Power Plants' provides recommendations regarding the implementation of Specific Safety Requirements: Design: Requirement 68 for emergency power systems. The Safety Guide outlines several design measures which are possible as a means of increasing the capability of the electrical power systems to cope with a station blackout, without providing detailed implementation guidance. A committee of international experts and advisors from numerous countries is currently working on an IAEA Technical Document (TECDOC) whose objective is to provide a common international technical basis from which the various criteria for SBO events need to be established, to support operation under design basis and design extension conditions (DEC) at nuclear power plants, to document in a comprehensive manner, all relevant aspects of SBO events at NPPs, and to outline critical issues which reflect the lessons learned from the Fukushima Dai-ichi accident. This paper discusses the commonly encountered difficulties associated with establishing the SBO criteria, shares the best practices, and current strategies used in the design and implementation of SBO provisions and outline the structure of the IAEA's SBO TECDOC under development. (author)

Sinister synergies : how competition for unregulated profit causes blackouts

International Nuclear Information System (INIS)

Wilson, J.

2005-01-01

This white paper examined the effects of deregulation on electricity system reliability and demonstrated that the pursuit of unregulated profit has increased blackout risk. It was suggested that although deregulation works well in some areas, experts, studies and experience have shown that the deregulation of the electricity system has failed. The make-up of the electricity system was discussed, as well as the importance of the system to security, safety, health and economic well-being. It was suggested that higher costs and the need for greater profits have pushed deregulated power producers to cut costs drastically and to invest where high, short-term returns are more likely, rather than focusing on reasonable long-term returns with reasonable cost savings and reliability. In addition, the complexity of deregulated electricity markets has afforded participants many opportunities to manipulate and cut corners to increase profits. It was suggested that higher costs and the need for higher profits have combined with deregulated market conditions to provide motives and opportunities for a culture of bad behavior. This has cost consumers billions of dollars and resulted in increased blackout risk. It was noted that there have also been significant cut-backs in training, maintenance and rehabilitation, as well as in research. There has been a large increase in the complexity of deregulated systems because of increased numbers of participants, transactions and relationships, which has led to the introduction of new systems without appropriate testing, pilot projects, risk management, gradual implementation and backup procedures. It was concluded that an independent investigation should be carried out, and that a major study is needed to examine deregulated environments. 31 refs

The Fukushima Accident: A Station Blackout and the Consequences

International Nuclear Information System (INIS)

Schäfer, F.; Tusheva, P.; Kliem, S.

2012-01-01

Lessons learned from Fukushima: • Underestimation of the role of the natural hazards • Insufficient protection of the emergency power and service water systems • Protection of fuel assembly storage pools insufficient • Safety review for Station Blackout and seismic evaluation needed • Diverse power supply systems, diverse sources for water delivery • Role of passive safety systems, they must work in a real passive manner and without electricity to open valves • Backup systems for reactor parameters monitoring • Revision of Severe Accident Management Guidelines and countermeasures for specific “rare” events • Early/late phase operators’ actions / Effectiveness of the operators’ actions

Extended blackout mitigation strategy for PWR

International Nuclear Information System (INIS)

Prošek, Andrej; Volkanovski, Andrija

2015-01-01

Highlights: • Equipment for mitigation of the extended blackout is investigated. • Analysis is done with deterministic safety analysis methods. • Strategy to prevent core heatup and not overfill steam generator is proposed. • Six types of reactor coolant system loss scenarios are investigated. • Pump flowrates and available start time to feed steam generators is determined. - Abstract: The accident at the Fukushima Daiichi nuclear power plant demonstrated the vulnerability of the plants on the loss of electrical power and loss of the ultimate heat sink events. A set of measures are proposed and currently implemented in response of the accident at the Fukushima Daiichi nuclear power plant. Those measures include diverse and flexible mitigation strategies that increase the defence-in-depth for beyond-design-basis scenarios. Mitigation strategies are based on the utilization of the portable equipment to provide power and water to the nuclear power plants in order to maintain or restore key safety functions. The verification of the proposed measures with the plant specific safety analyses is endorsed in the mitigation strategies. This paper investigates utilization of the turbine driven auxiliary feedwater pump (TD-AFW) or portable water injection pump for the mitigation of the event of loss of all alternate current sources and batteries (extended station blackout). Methodology for assessment of the required pump injection flow rate with the application of the standard deterministic safety analysis code is developed and presented. The required injection rate to the steam generators is calculated from the cumulative water mass injected by the turbine driven auxiliary feedwater pump in the analysed scenarios, when desired normal level is maintained automatically. The developed methodology allows assessment of the required injections rates of pump, TD-AFW or portable, for different plant configurations and number of flow rate changes. The methodology is applied

Extended blackout mitigation strategy for PWR

Energy Technology Data Exchange (ETDEWEB)

Prošek, Andrej, E-mail: andrej.prosek@ijs.si; Volkanovski, Andrija, E-mail: andrija.volkanovski@ijs.si

2015-12-15

Highlights: • Equipment for mitigation of the extended blackout is investigated. • Analysis is done with deterministic safety analysis methods. • Strategy to prevent core heatup and not overfill steam generator is proposed. • Six types of reactor coolant system loss scenarios are investigated. • Pump flowrates and available start time to feed steam generators is determined. - Abstract: The accident at the Fukushima Daiichi nuclear power plant demonstrated the vulnerability of the plants on the loss of electrical power and loss of the ultimate heat sink events. A set of measures are proposed and currently implemented in response of the accident at the Fukushima Daiichi nuclear power plant. Those measures include diverse and flexible mitigation strategies that increase the defence-in-depth for beyond-design-basis scenarios. Mitigation strategies are based on the utilization of the portable equipment to provide power and water to the nuclear power plants in order to maintain or restore key safety functions. The verification of the proposed measures with the plant specific safety analyses is endorsed in the mitigation strategies. This paper investigates utilization of the turbine driven auxiliary feedwater pump (TD-AFW) or portable water injection pump for the mitigation of the event of loss of all alternate current sources and batteries (extended station blackout). Methodology for assessment of the required pump injection flow rate with the application of the standard deterministic safety analysis code is developed and presented. The required injection rate to the steam generators is calculated from the cumulative water mass injected by the turbine driven auxiliary feedwater pump in the analysed scenarios, when desired normal level is maintained automatically. The developed methodology allows assessment of the required injections rates of pump, TD-AFW or portable, for different plant configurations and number of flow rate changes. The methodology is applied

Evaluation of Station Blackout accidents at nuclear power plants. Technical findings related to Unresolved Safety Issue A-44. Draft report for comment

International Nuclear Information System (INIS)

Baranowsky, P.W.

1985-05-01

''Station Blackout,'' which is the complete loss of alternating current (ac) electrical power in a nuclear power plant, has been designated as Unresolved Safety Issue A-44. Because many safety systems required for reactor core decay heat removal and containment heat removal depend on ac power, the consequences of a station blackout could be severe. This report documents the findings of technical studies performed as part of the program to resolve this issue. The important factors analyzed include: the frequency of loss of offsite power; the probability that emergency or onsite ac power supplies would be unavailable; the capability and reliability of decay heat removal systems independent of ac power; and the likelihood that offsite power would be restored before systems that cannot operate for extended periods without ac power fail, thus resulting in core damage. This report also addresses effects of different designs, locations, and operational features on the estimated frequency of core damage resulting from station blackout events

Silencing Boko Haram: Mobile Phone Blackout and Counterinsurgency in Nigeria’s Northeast region

Directory of Open Access Journals (Sweden)

Jacob Udo-Udo Jacob

2015-03-01

Full Text Available In the summer of 2013, the Nigerian military, as part of its counterinsurgency operations against Boko Haram insurgents, shut down GSM mobile telephony in three northeast states – Adamawa, Borno and Yobe. This article explores the rationale, impact and citizens’ opinion of the mobile phone blackout. It draws on focus group discussions with local opinion leaders and in-depth personal interviews with military and security insiders, as well as data of Boko Haram incidences before, during and after the blackout from military sources and conflict databases. It argues that, although the mobile phone shutdown was ‘successful’ from a military- tactical point of view, it angered citizens and engendered negative opinions toward the state and new emergency policies. While citizens developed various coping and circumventing strategies, Boko Haram evolved from an open network model of insurgency to a closed centralized system, shifting the center of its operations to the Sambisa Forest. This fundamentally changed the dynamics of the conflict. The shutdown demonstrated, among others, that while ICTs serve various desirable purposes for developing states, they will be jettisoned when their use challenges the state’s legitimacy and raison d'être, but not without consequences.

Interpreting transnational infrastructure vulnerability: European blackout and the historical dynamics of transnational electricity governance

International Nuclear Information System (INIS)

Vleuten, Erik van der; Lagendijk, Vincent

2010-01-01

Recent transnational blackouts exposed two radically opposed interpretations of Europe's electricity infrastructure, which inform recent and ongoing negotiations on transnational electricity governance. To EU policy makers such blackouts revealed the fragility of Europe's power grids and the need of a more centralized form of governance, thus legitimizing recent EU interventions. Yet to power sector spokespersons, these events confirmed the reliability of transnational power grids and the traditional decentralized governance model: the disturbances were quickly contained and repaired. This paper inquires the historic legacies at work in these conflicting interpretations and associated transnational governance preferences. It traces the power sector's interpretation to its building of a secure transnational power grid from the 1950s through the era of neoliberalization. Next it places the EU interpretation and associated policy measures against the historical record of EU attempts at transnational infrastructure governance. Uncovering the historical roots and embedding of both interpretations, we conclude that their divergence is of a surprisingly recent date and relates to the current era of security thinking. Finally we recommend transnational, interpretative, and historical analysis to the field of critical infrastructure studies.

Comparison of the MAAP4 code with the station blackout simulation in the IIST facility

International Nuclear Information System (INIS)

Robert E Henry; Christopher E Henry; Chan Y Paik; George M Hauser

2005-01-01

Full text of publication follows: The Modular Accident Analysis Program (MAAP) is an integral system model to assess challenges to the reactor core, Reactor Coolant System (RCS) and containment for accident conditions. MAAP4 is the current version used by the MAAP Users Group to assess the responses to a spectrum of accident conditions. Benchmarking of the MAAP code with integral system experiments has been a continuing effort by MAAP developers and users. Several of these have been configured into dynamic benchmarks and are included in Volume III (Benchmarking) of the MAAP4 Users Manual (EPRI, 2004). One such integral experiment is the INER integral system test (IIST) constructed at the Institute of Nuclear Energy Research in Taiwan. This experimental facility is a reduced height, reduced pressure representation of a 3-loop PWR and has been used to examine several different types of accident sequences. One of these is a station blackout simulation with loss of auxiliary feedwater at the time that the transient is initiated. This is an important integral experiment to be compared with the MAAP4 code models. A parameter file (those values representing the system design and boundary experimental conditions) has been developed for the IIST facility and an input deck has been configured to represent a station blackout sequence with instantaneous loss of auxiliary feedwater. Of importance in this benchmark is (a) the rate at which the secondary side inventory is depleted, (b) the depletion of water within the reactor pressure vessel and (c) the time at which the top of the reactor core is uncovered. Comparisons have been made with these three different intervals and there is good agreement between the timing of these events for the MAAP4 benchmark. This is important since this reference sequence represents a set of boundary conditions that is continually with subsequent analyses being perturbations on this type of accident sequence. The good agreement between MAAP4 and

An adaptive reentry guidance method considering the influence of blackout zone

Science.gov (United States)

Wu, Yu; Yao, Jianyao; Qu, Xiangju

2018-01-01

Reentry guidance has been researched as a popular topic because it is critical for a successful flight. In view that the existing guidance methods do not take into account the accumulated navigation error of Inertial Navigation System (INS) in the blackout zone, in this paper, an adaptive reentry guidance method is proposed to obtain the optimal reentry trajectory quickly with the target of minimum aerodynamic heating rate. The terminal error in position and attitude can be also reduced with the proposed method. In this method, the whole reentry guidance task is divided into two phases, i.e., the trajectory updating phase and the trajectory planning phase. In the first phase, the idea of model predictive control (MPC) is used, and the receding optimization procedure ensures the optimal trajectory in the next few seconds. In the trajectory planning phase, after the vehicle has flown out of the blackout zone, the optimal reentry trajectory is obtained by online planning to adapt to the navigation information. An effective swarm intelligence algorithm, i.e. pigeon inspired optimization (PIO) algorithm, is applied to obtain the optimal reentry trajectory in both of the two phases. Compared to the trajectory updating method, the proposed method can reduce the terminal error by about 30% considering both the position and attitude, especially, the terminal error of height has almost been eliminated. Besides, the PIO algorithm performs better than the particle swarm optimization (PSO) algorithm both in the trajectory updating phase and the trajectory planning phases.

Characterization of weakly ionized argon flows for radio blackout mitigation experiments

Science.gov (United States)

Steffens, L.; Koch, U.; Esser, B.; Gülhan, A.

2017-06-01

For reproducing the so-called E × B communication blackout mitigation scheme inside the L2K arc heated facility of the DLR in weakly ionized argon §ows, a §at plate model has been equipped with a superconducting magnet, electrodes, and a setup comprising microwave plasma transmission spectroscopy (MPTS). A thorough characterization of the weakly ionized argon §ow has been performed including the use of microwave interferometry (MWI), Langmuir probe measurements, Pitot probe pro¦les, and spectroscopic methods like diode laser absorption spectroscopy (DLAS) and emission spectroscopy.

PWR station blackout transient simulation in the INER integral system test facility

International Nuclear Information System (INIS)

Liu, T.J.; Lee, C.H.; Hong, W.T.; Chang, Y.H.

2004-01-01

Station blackout transient (or TMLB' scenario) in a pressurized water reactor (PWR) was simulated using the INER Integral System Test Facility (IIST) which is a 1/400 volumetrically-scaled reduce-height and reduce-pressure (RHRP) simulator of a Westinghouse three-loop PWR. Long-term thermal-hydraulic responses including the secondary boil-off and the subsequent primary saturation, pressurization and core uncovery were simulated based on the assumptions of no offsite and onsite power, feedwater and operator actions. The results indicate that two-phase discharge is the major depletion mode since it covers 81.3% of the total amount of the coolant inventory loss. The primary coolant inventory has experienced significant re-distribution during a station blackout transient. The decided parameter to avoid the core overheating is not the total amount of the coolant inventory remained in the primary core cooling system but only the part of coolant left in the pressure vessel. The sequence of significant events during transient for the IIST were also compared with those of the ROSA-IV large-scale test facility (LSTF), which is a 1/48 volumetrically-scaled full-height and full-pressure (FHFP) simulator of a PWR. The comparison indicates that the sequence and timing of these events during TMLB' transient studied in the RHRP IIST facility are generally consistent with those of the FHFP LSTF. (author)

Modelling of blackout sequence at Atucha-1 using the MARCH3 code

International Nuclear Information System (INIS)

Baron, J.; Bastianelli, B.

1997-01-01

This paper presents the modelling of a complete blackout at the Atucha-1 NPP as preliminary phase for a Level II safety probabilistic analysis. The MARCH3 code of the STCP (Source Term Code Package) is used, based on a plant model made in accordance with particularities of the plant design. The analysis covers all the severe accident phases. The results allow to view the time sequence of the events, and provide the basis for source term studies. (author). 6 refs., 2 figs

Acute Alcohol Effects on Narrative Recall and Contextual Memory: An Examination of Fragmentary Blackouts

OpenAIRE

Wetherill, Reagan R.; Fromme, Kim

2011-01-01

The present study examined the effects of alcohol consumption on narrative recall and contextual memory among individuals with and without a history of fragmentary blackouts in an attempt to better understand why some individuals experience alcohol-induced memory impairments whereas others do not, even at comparable blood alcohol concentrations (BACs). Standardized beverage (alcohol, no alcohol) administration procedures and neuropsychological assessments measured narrative recall and context...

Binge Drinking and the Young Brain: A Mini Review of the Neurobiological Underpinnings of Alcohol-Induced Blackout

Directory of Open Access Journals (Sweden)

Daniel F. Hermens

2018-01-01

Full Text Available Binge drinking has significant effects on memory, particularly with regards to the transfer of information to long-term storage. Partial or complete blocking of memory formation is known as blackout. Youth represents a critical period in brain development that is particularly vulnerable to alcohol misuse. Animal models show that the adolescent brain is more vulnerable to the acute and chronic effects of alcohol compared with the adult brain. This mini-review addresses the neurobiological underpinnings of binge drinking and associated memory loss (blackout in the adolescent and young adult period. Although the extent to which there are pre-existing versus alcohol-induced neurobiological changes remains unclear, it is likely that repetitive binge drinking in youth has detrimental effects on cognitive and social functioning. Given its role in learning and memory, the hippocampus is a critical region with neuroimaging research showing notable changes in this structure associated with alcohol misuse in young people. There is a great need for earlier identification of biological markers associated with alcohol-related brain damage. As a means to assess in vivo neurochemistry, magnetic resonance spectroscopy (MRS has emerged as a particularly promising technique since changes in neurometabolites often precede gross structural changes. Thus, the current paper addresses how MRS biomarkers of neurotransmission (glutamate, GABA and oxidative stress (indexed by depleted glutathione in the hippocampal region of young binge drinkers may underlie propensity for blackouts and other memory impairments. MRS biomarkers may have particular utility in determining the acute versus longer-term effects of binge drinking in young people.

Probabilistic assessment of Juragua Nuclear Power Plant response under station blackout conditions

International Nuclear Information System (INIS)

Valhuerdi, C.; Vilaragut, J.J.; Perdomo, M.; Torres, A.

1995-01-01

The preliminary results concerning the response of station blackout are shown in this paper. These results have been obtained in the framework of initiator lass of external electrical supply as a aport of the revision o of the current probabilistic safety analysis. The work is also based on the results reported in the thermohydraulic calculations of VVER 440 plants responses under these conditions and the experience of this type of notified incidents. Finally, a comparative analysis with the results obtained for other reactor technologies is presented

Transfer Effect Ratio of Loosely Coupled Coils for Wireless Power through CB Wall under Station Blackout(SBO)

International Nuclear Information System (INIS)

Koo, Kil Mo; Hong, Seong Wan; Song, Jin Ho; Baek, Won Pil; Cheon, Sang Hoon

2016-01-01

Instrumentations have had the bad situation like a station blackout(SBO) as the severe accident in nuclear power plants. In recent years, there has been an increasing interest in wireless power transfer technology, In particular, significant processing has been charted for inductively coupled systems. In this paper, we introduce some new method as transfer effect ratio of loosely coupled coils for wireless power through the CB(Container Building) wall as an alternative method under a station blackout of severe accident conditions in nuclear power plants. As an equivalent circuit model that can describe wireless energy transfer systems via coupled magnetic resonances for the CB thickness wall. The solution shows that the transmission efficiency can be decreased simply by adjusting the spacing between the power and the sending coils or between the receiving and the load coils. The system design can be calculated the frequency characteristics, and then an equivalent circuit model was developed from the node equation and established in an electric design automation tool

Transfer Effect Ratio of Loosely Coupled Coils for Wireless Power through CB Wall under Station Blackout(SBO)

Energy Technology Data Exchange (ETDEWEB)

Koo, Kil Mo; Hong, Seong Wan; Song, Jin Ho; Baek, Won Pil [KAERI, Daejeon (Korea, Republic of); Cheon, Sang Hoon [ETRI, Daejeon (Korea, Republic of)

2016-05-15

Instrumentations have had the bad situation like a station blackout(SBO) as the severe accident in nuclear power plants. In recent years, there has been an increasing interest in wireless power transfer technology, In particular, significant processing has been charted for inductively coupled systems. In this paper, we introduce some new method as transfer effect ratio of loosely coupled coils for wireless power through the CB(Container Building) wall as an alternative method under a station blackout of severe accident conditions in nuclear power plants. As an equivalent circuit model that can describe wireless energy transfer systems via coupled magnetic resonances for the CB thickness wall. The solution shows that the transmission efficiency can be decreased simply by adjusting the spacing between the power and the sending coils or between the receiving and the load coils. The system design can be calculated the frequency characteristics, and then an equivalent circuit model was developed from the node equation and established in an electric design automation tool.

Thermohydraulic and safety analysis on China advanced research reactor under station blackout accident

International Nuclear Information System (INIS)

Tian Wenxi; Qiu Suizheng; Su Guanghui; Jia Dounan; Liu Xingmin; Zhang Jianwei

2007-01-01

A thermohydraulic and safety analysis code-TSACC has been developed using Fortran90 language to evaluate the transient thermohydraulic behavior of the China advanced research reactor (CARR) under station blackout accident (SBA). For the development of TSACC, a series of corresponding mathematical and physical models were applied. Point reactor neutron kinetics model was adopted for solving the reactor power. All possible flow and heat transfer conditions under station blackout accident were considered and the optional correlations were supplied. The usual finite difference method was abandoned and the integral technique was adopted to evaluate the temperature field of the plate type fuel elements. A new simple and convenient equation was proposed for the resolution of the transient behaviors of the main pump instead of the complicated four-quadrant model. Gear method and Adams method were adopted alternately for a better solution to the stiff differential equations describing the dynamic behavior of the CARR. The computational result of TSACC showed the adequacy of the safety margin of CARR under SBA. For the purpose of Verification and Validation (V and V), the simulated results of TSACC were compared with those of RELAP5/MOD3 and a good agreement was obtained. The adoption of modular programming techniques enables TASCC to be applied to other reactors by easily modifying the corresponding function modules

Blackout risk prevention in a smart grid based flexible optimal strategy using Grey Wolf-pattern search algorithms

International Nuclear Information System (INIS)

Mahdad, Belkacem; Srairi, K.

2015-01-01

Highlights: • A generalized optimal security power system planning strategy for blackout risk prevention is proposed. • A Grey Wolf Optimizer dynamically coordinated with Pattern Search algorithm is proposed. • A useful optimized database dynamically generated considering margin loading stability under severe faults. • The robustness and feasibility of the proposed strategy is validated in the standard IEEE 30 Bus system. • The proposed planning strategy will be useful for power system protection coordination and control. - Abstract: Developing a flexible and reliable power system planning strategy under critical situations is of great importance to experts and industrials to minimize the probability of blackouts occurrence. This paper introduces the first stage of this practical strategy by the application of Grey Wolf Optimizer coordinated with pattern search algorithm for solving the security smart grid power system management under critical situations. The main objective of this proposed planning strategy is to prevent the practical power system against blackout due to the apparition of faults in generating units or important transmission lines. At the first stage the system is pushed to its margin stability limit, the critical loads shedding are selected using voltage stability index. In the second stage the generator control variables, the reactive power of shunt and dynamic compensators are adjusted in coordination with minimization the active and reactive power at critical loads to maintain the system at security state to ensure service continuity. The feasibility and efficiency of the proposed strategy is applied to IEEE 30-Bus test system. Results are promising and prove the practical efficiency of the proposed strategy to ensure system security under critical situations

Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

Directory of Open Access Journals (Sweden)

Yusuke Takahashi

2016-01-01

Full Text Available A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD of the European Space Agency (ESA in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense plasma derived from a strong shock wave generated in front of the capsule because of orbital speed during reentry. In this study, the physical properties of the plasma flow in the shock layer and wake region of the ESA ARD were obtained using a computational fluid dynamics technique. Then, electromagnetic waves were expressed using a frequency-dependent finite-difference time-domain method using the plasma properties. The analysis model was validated based on experimental flight data. A comparison of the measured and predicted results showed good agreement. The distribution of charged particles around the ESA ARD and the complicated behavior of electromagnetic waves, with attenuation and reflection, are clarified in detail. It is suggested that the analysis model could be an effective tool for investigating radio frequency blackout and plasma attenuation in radio wave communication.

Advanced validation of CFD-FDTD combined method using highly applicable solver for reentry blackout prediction

International Nuclear Information System (INIS)

Takahashi, Yusuke

2016-01-01

An analysis model of plasma flow and electromagnetic waves around a reentry vehicle for radio frequency blackout prediction during aerodynamic heating was developed in this study. The model was validated based on experimental results from the radio attenuation measurement program. The plasma flow properties, such as electron number density, in the shock layer and wake region were obtained using a newly developed unstructured grid solver that incorporated real gas effect models and could treat thermochemically non-equilibrium flow. To predict the electromagnetic waves in plasma, a frequency-dependent finite-difference time-domain method was used. Moreover, the complicated behaviour of electromagnetic waves in the plasma layer during atmospheric reentry was clarified at several altitudes. The prediction performance of the combined model was evaluated with profiles and peak values of the electron number density in the plasma layer. In addition, to validate the models, the signal losses measured during communication with the reentry vehicle were directly compared with the predicted results. Based on the study, it was suggested that the present analysis model accurately predicts the radio frequency blackout and plasma attenuation of electromagnetic waves in plasma in communication. (paper)

Investigation of station blackout scenario in VVER440/v230 with RELAP5 computer code

Energy Technology Data Exchange (ETDEWEB)

Gencheva, Rositsa Veselinova, E-mail: roseh@mail.bg; Stefanova, Antoaneta Emilova, E-mail: antoanet@inrne.bas.bg; Groudev, Pavlin Petkov, E-mail: pavlinpg@inrne.bas.bg

2015-12-15

Highlights: • We have modeled SBO in VVER440. • RELAP5/MOD3 computer code has been used. • Base case calculation has been done. • Fail case calculation has been done. • Operator and alternative operator actions have been investigated. - Abstract: During the development of symptom-based emergency operating procedures (SB-EOPs) for VVER440/v230 units at Kozloduy Nuclear Power Plant (NPP) a number of analyses have been performed using the RELAP5/MOD3 (Carlson et al., 1990). Some of them investigate the response of VVER440/v230 during the station blackout (SBO). The main purpose of the analyses presented in this paper is to identify the behavior of important VVER440 parameters in case of total station blackout. The RELAP5/MOD3 has been used to simulate the SBO in VVER440 NPP model (Fletcher and Schultz, 1995). This model was developed at the Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences (INRNE-BAS), Sofia, for analyses of operational occurrences, abnormal events and design based scenarios. The model provides a significant analytical capability for specialists working in the field of NPP safety.

Investigation of accident management procedures related to loss of feedwater and station blackout in PSB-VVER integral test facility

Energy Technology Data Exchange (ETDEWEB)

Bucalossi, A. [EC JRC, (JRC F.5) PO Box 2, 1755 ZG Petten (Netherlands); Del Nevo, A., E-mail: alessandro.delnevo@enea.it [ENEA, C.R. Brasimone, 40032 Camugnano (Italy); Moretti, F.; D' Auria, F. [GRNSPG, Universita di Pisa, via Diotisalvi 2, 56100 Pisa (Italy); Elkin, I.V.; Melikhov, O.I. [Electrogorsk Research and Engineering Centre, Electrogorsk, Moscow Region (Russian Federation)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Four integral test facility experiments related to VVER-1000 reactor. Black-Right-Pointing-Pointer TH response of the VVER-1000 primary system following total loss of feedwater and station blackout scenarios. Black-Right-Pointing-Pointer Accident management procedures in case of total loss of feedwater and station blackout. Black-Right-Pointing-Pointer Experimental data represent an improvement of existing database for TH code validation. - Abstract: VVER 1000 reactors have some unique and specific features (e.g. large primary and secondary side fluid inventory, horizontal steam generators, core design) that require dedicated experimental and analytical analyses in order to assess the performance of safety systems and the effectiveness of possible accident management strategies. The European Commission funded project 'TACIS 2.03/97', Part A, provided valuable experimental data from the large-scale (1:300) PSB-VVER test facility, investigating accident management procedures in VVER-1000 reactor. A test matrix was developed at University of Pisa (responsible of the project) with the objective of obtaining the experimental data not covered by the OECD VVER validation matrix and with main focus on accident management procedures. Scenarios related to total loss of feed water and station blackout are investigated by means of four experiments accounting for different countermeasures, based on secondary cooling strategies and primary feed and bleed procedures. The transients are analyzed thoroughly focusing on the identification of phenomena that will challenge the code models during the simulations.

Analysis of hot leg natural circulation under station blackout severe accident

International Nuclear Information System (INIS)

Deng Jian; Cao Xuewu

2007-01-01

Under severe accidents, natural circulation flows are important to influence the accident progression and result in a pressurized water reactor (PWR). In a station blackout accident with no recovery of steam generator (SG) auxiliary feedwater (TMLB' severe accident scenario), the hot leg countercurrent natural circulation flow is analyzed by using a severe-accident code, to better understand its potential impacts on the creep-rupture timing among the surge line, the hot leg; and SG tubes. The results show that the natural circulation may delay the failure time of the hot leg. The recirculation ratio and the hot mixing factor are also calculated and discussed. (authors)

Analysis of Peach Bottom station blackout with MELCOR

International Nuclear Information System (INIS)

Dingman, S.E.; Cole, R.K.; Haskin, F.E.; Summers, R.M.; Webb, S.W.

1987-01-01

A demonstration analysis of station blackout at Peach Bottom has been performed using MELCOR and the results have been compared with those from MARCON 2.1B and the Source Term Code Package (STCP). MELCOR predicts greater in-vessel hydrogen production, earlier melting and core collapse, but later debris discharge than MARCON 2.1B. The drywell fails at vessel breach in MELCOR, but failure is delayed about an hour in MARCON 2.1B. These differences are mainly due to the MELCOR models for candling during melting, in-core axial conduction, and continued oxidation and heat transfer from core debris following lower head dryout. Three sensitivity calculations have been performed with MELCOR to address uncertainties regarding modeling of the core-concrete interactions. The timing of events and the gas and radionuclide release rates are somewhat different in the base case and the three sensitivity cases, but the final conditions and total releases are similar

Evaluating the Effect of a Campus-Wide Social Norms Marketing Intervention on Alcohol-Use Perceptions, Consumption, and Blackouts

Science.gov (United States)

Su, Jinni; Hancock, Linda; Wattenmaker McGann, Amanda; Alshagra, Mariam; Ericson, Rhianna; Niazi, Zackaria; Dick, Danielle M.; Adkins, Amy

2018-01-01

Objective: To evaluate the effect of a campus-wide social norms marketing intervention on alcohol-use perceptions, consumption, and blackouts at a large, urban, public university. Participants: 4,172 college students (1,208 freshmen, 1,159 sophomores, 953 juniors, and 852 seniors) who completed surveys in Spring 2015 for the Spit for Science…

Uncertainty and sensitivity analysis for the simulation of a station blackout scenario in the Jules Horowitz Reactor

International Nuclear Information System (INIS)

Ghione, Alberto; Noel, Brigitte; Vinai, Paolo; Demazière, Christophe

2017-01-01

Highlights: • A station blackout scenario in the Jules Horowitz Reactor is analyzed using CATHARE. • Input and model uncertainties relevant to the transient, are considered. • A statistical methodology for the propagation of the uncertainties is applied. • No safety criteria are exceeded and sufficiently large safety margins are estimated. • The most influential uncertainties are determined with a sensitivity analysis. - Abstract: An uncertainty and sensitivity analysis for the simulation of a station blackout scenario in the Jules Horowitz Reactor (JHR) is presented. The JHR is a new material testing reactor under construction at CEA on the Cadarache site, France. The thermal-hydraulic system code CATHARE is applied to investigate the response of the reactor system to the scenario. The uncertainty and sensitivity study was based on a statistical methodology for code uncertainty propagation, and the ‘Uncertainty and Sensitivity’ platform URANIE was used. Accordingly, the input uncertainties relevant to the transient, were identified, quantified, and propagated to the code output. The results show that the safety criteria are not exceeded and sufficiently large safety margins exist. In addition, the most influential input uncertainties on the safety parameters were found by making use of a sensitivity analysis.

Blackout sequence modeling for Atucha-I with MARCH3 code

International Nuclear Information System (INIS)

Baron, J.; Bastianelli, B.

1997-01-01

The modeling of a blackout sequence in Atucha I nuclear power plant is presented in this paper, as a preliminary phase for a level II probabilistic safety assessment. Such sequence is analyzed with the code MARCH3 from STCP (Source Term Code Package), based on a specific model developed for Atucha, that takes into accounts it peculiarities. The analysis includes all the severe accident phases, from the initial transient (loss of heat sink), loss of coolant through the safety valves, core uncovered, heatup, metal-water reaction, melting and relocation, heatup and failure of the pressure vessel, core-concrete interaction in the reactor cavity, heatup and failure of the containment building (multi-compartmented) due to quasi-static overpressurization. The results obtained permit to visualize the time sequence of these events, as well as provide the basis for source term studies. (author) [es

Real-time stability in power systems techniques for early detection of the risk of blackout

CERN Document Server

Savulescu, Savu

2014-01-01

This pioneering volume has been updated and enriched to reflect the state-of-the-art in blackout prediction and prevention. It documents and explains background and algorithmic aspects of the most successful steady-state, transient and voltage stability solutions available today in real-time. It also describes new, cutting-edge stability applications of synchrophasor technology, and captures industry acceptance of metrics and visualization tools that quantify and monitor the distance to instability. Expert contributors review a broad spectrum of additionally available techniques, such as traje

Demonstration of fully coupled simplified extended station black-out accident simulation with RELAP-7

Energy Technology Data Exchange (ETDEWEB)

Zhao, Haihua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Hongbin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zou, Ling [Idaho National Lab. (INL), Idaho Falls, ID (United States); Anders, David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-10-01

The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The RELAP-7 code develop-ment effort started in October of 2011 and by the end of the second development year, a number of physical components with simplified two phase flow capability have been de-veloped to support the simplified boiling water reactor (BWR) extended station blackout (SBO) analyses. The demonstration case includes the major components for the primary system of a BWR, as well as the safety system components for the safety relief valve (SRV), the reactor core isolation cooling (RCIC) system, and the wet well. Three scenar-ios for the SBO simulations have been considered. Since RELAP-7 is not a severe acci-dent analysis code, the simulation stops when fuel clad temperature reaches damage point. Scenario I represents an extreme station blackout accident without any external cooling and cooling water injection. The system pressure is controlled by automatically releasing steam through SRVs. Scenario II includes the RCIC system but without SRV. The RCIC system is fully coupled with the reactor primary system and all the major components are dynamically simulated. The third scenario includes both the RCIC system and the SRV to provide a more realistic simulation. This paper will describe the major models and dis-cuss the results for the three scenarios. The RELAP-7 simulations for the three simplified SBO scenarios show the importance of dynamically simulating the SRVs, the RCIC sys-tem, and the wet well system to the reactor safety during extended SBO accidents.

Cooling methods of station blackout scenario for LWR plants

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-08-15

The objective of this study is to analyze the cooling method of station blackout scenario for both the BWR and PWR plants by RELAP5 code and to check the validity of the cooling method proposed by the utilities. In the BWR plant cooling scenario, the Reactor Core Isolation Cooling System (RCIC), which is operated with high pressure steam from the reactor, injects cooling water into the reactor to keep the core water level. The steam generated in the core is released into the suppression pool at containment vessel to condense. To restrict the containment vessel pressure rising, the ventilation from the wet-well is operated. The scenario is analyzed by RELAP5 code. In the PWR plant scenario, the primary pressure is decreased by the turbine-driven auxiliary feed water system operated with secondary side steam of the steam generators (SGs). And the core cooling is kept by the natural circulation flow at the primary loop. From the RELAP5 code analysis, it was shown that the primary system cooling was practicable by using the turbine-driven auxiliary feed water system. (author)

Cooling methods of station blackout scenario for LWR plants

International Nuclear Information System (INIS)

2012-01-01

The objective of this study is to analyze the cooling method of station blackout scenario for both the BWR and PWR plants by RELAP5 code and to check the validity of the cooling method proposed by the utilities. In the BWR plant cooling scenario, the Reactor Core Isolation Cooling System (RCIC), which is operated with high pressure steam from the reactor, injects cooling water into the reactor to keep the core water level. The steam generated in the core is released into the suppression pool at containment vessel to condense. To restrict the containment vessel pressure rising, the ventilation from the wet-well is operated. The scenario is analyzed by RELAP5 and CONTEMPT-LT code. In the PWR plant scenario, the primary pressure is decreased by the turbine-driven auxiliary feed water system operated with secondary side steam of the steam generators (SGs). And the core cooling is kept by the natural circulation flow at the primary loop. The analytical method of un-uniform flow behavior among the SG U-tubes, which affects the natural circulation flow rate, is developed. (author)

Analysis of station blackout accidents for the Bellefonte pressurized water reactor

International Nuclear Information System (INIS)

Gasser, R.D.; Bieniarz, P.P.; Tills, J.L.

1986-09-01

An analysis has been performed for the Bellefonte PWR Unit 1 to determine the containment loading and the radiological releases into the environment from a station blackout accident. A number of issues have been addressed in this analysis which include the effects of direct heating on containment loading, and the effects of fission product heating and natural convection on releases from the primary system. The results indicate that direct heating which involves more than about 50% of the core can fail the Bellefonte containment, but natural convection in the RCS may lead to overheating and failure of the primary system piping before core slump, thus, eliminating or mitigating direct heating. Releases from the primary system are significantly increased before vessel breach due to natural circulation and after vessel breach due to reevolution of retained fission products by fission product heating of RCS structures

MELCOR simulation of long-term station blackout at Peach Bottom

International Nuclear Information System (INIS)

Madni, I.K.

1990-01-01

This paper presents the results from MELCOR (Version 1.8BC) calculations of the Long-Term Station Blackout Accident Sequence, with failure to depressurize the reactor vessel, at the Peach Bottom (BWR Mark I) plant, and presents comparisons with Source Term Code Package (STCP) calculations of the same sequence. This sequence assumes that batteries are available for six hours following loss of all power to the plant. Following battery failure, the reactor coolant system (RCS) inventory is boiled off through the relief valves by continued decay heat generation. This leads to core uncovery, heatup, clad oxidation, core degradation, relocation, and, eventually, vessel failure at high pressure. STCP has calculated the transient out to 13.5 hours after core uncovery. The results include the timing of key events, pressure and temperature response in the reactor vessel and containment, hydrogen production, and the release of source terms to the environment. 12 refs., 23 figs., 3 tabs

Resonant interaction of electromagnetic wave with plasma layer and overcoming the radiocommunication blackout problem

Science.gov (United States)

Bogatskaya, A. V.; Klenov, N. V.; Tereshonok, M. V.; Adjemov, S. S.; Popov, A. M.

2018-05-01

We present an analysis of the possibility of penetrating electromagnetic waves through opaque media using an optical-mechanical analogy. As an example, we consider the plasma sheath surrounding the vehicle as a potential barrier and analyze the overcoming of radiocommunication blackout problem. The idea is to embed a «resonator» between the surface on the vehicle and plasma sheath which is supposed to provide an effective tunneling of the signal to the receiving antenna. We discuss the peculiarities of optical mechanical analogy applicability and analyze the radio frequency wave tunneling regime in detail. The cases of normal and oblique incidence of radiofrequency waves on the vehicle surface are studied.

The Threshold of the State: Civil Defence, the Blackout and the Home in Second World War Britain.

Science.gov (United States)

Greenhalgh, James

2017-06-01

This article reconsiders the way that the British state extended its control of the home during the Second World War, using the implementation of air raid precautions and the blackout as a lens through which to view the state's developing attitudes to domestic space. Presented here is not the familiar story of pitch-dark, dangerous streets or altered cityscapes of fear and destruction; instead, by examining personal testimony the article inverts traditional treatments of the blackout to look at the interior of dwellings, demonstrating how the realities of total warfare impinged upon the psychological elements that constituted the home. What emerges not only expands historical understandings of the wartime experience of civilians, it also shows civil defence measures as highly visible points on an often antagonistic trajectory of state interactions with citizens concerning the privacy and security of the dwelling in the modern city. The requirements of civil defence, I argue, were not merely the product of exceptional wartime circumstances, but symptomatic of long-standing attempts to open up dwellings to state scrutiny. These attempts had both a significant pre-war lineage and, crucially, implications beyond the end of the war in private homes and on social housing estates. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Main considerations for modelling a station blackout scenario with trace

International Nuclear Information System (INIS)

Querol, Andrea; Turégano, Jara; Lorduy, María; Gallardo, Sergio; Verdú, Gumersindo

2017-01-01

In the nuclear safety field, the thermal hydraulic phenomena that take place during an accident in a nuclear power plant is of special importance. One of the most studied accidents is the Station BlackOut (SBO). The aim of the present work is the analysis of the PKL integral test facility nodalization using the thermal-hydraulic code TRACE5 to reproduce a SBO accidental scenario. The PKL facility reproduces the main components of the primary and secondary systems of its reference nuclear power plant (Philippsburg II). The results obtained with different nodalization have been compared: 3D vessel vs 1D vessel, Steam Generator (SG) modelling using PIPE or TEE components and pressurizer modelling with PIPE or PRIZER components. Both vessel nodalization (1D vessel and 3D vessel) reproduce the physical phenomena of the experiment. However, there are significant discrepancies between them. The appropriate modelling of the SG is also relevant in the results. Regarding the other nodalization (PIPE or TEE components for SG and PIPE or PRIZER components for pressurizer), do not produce relevant differences in the results. (author)

Main considerations for modelling a station blackout scenario with trace

Energy Technology Data Exchange (ETDEWEB)

Querol, Andrea; Turégano, Jara; Lorduy, María; Gallardo, Sergio; Verdú, Gumersindo, E-mail: anquevi@upv.es, E-mail: jaturna@upv.es, E-mail: maloral@upv.es, E-mail: sergalbe@iqn.upv.es, E-mail: gverdu@iqn.upv.es [Instituto Universitario de Seguridad Industrial, Radiofísica y Medioambiental (ISIRYM), Universitat Politècnica de València (Spain)

2017-07-01

In the nuclear safety field, the thermal hydraulic phenomena that take place during an accident in a nuclear power plant is of special importance. One of the most studied accidents is the Station BlackOut (SBO). The aim of the present work is the analysis of the PKL integral test facility nodalization using the thermal-hydraulic code TRACE5 to reproduce a SBO accidental scenario. The PKL facility reproduces the main components of the primary and secondary systems of its reference nuclear power plant (Philippsburg II). The results obtained with different nodalization have been compared: 3D vessel vs 1D vessel, Steam Generator (SG) modelling using PIPE or TEE components and pressurizer modelling with PIPE or PRIZER components. Both vessel nodalization (1D vessel and 3D vessel) reproduce the physical phenomena of the experiment. However, there are significant discrepancies between them. The appropriate modelling of the SG is also relevant in the results. Regarding the other nodalization (PIPE or TEE components for SG and PIPE or PRIZER components for pressurizer), do not produce relevant differences in the results. (author)

Economic simplified boiling water reactor (ESBWR) response to an extended station blackout/ loss of all AC power

International Nuclear Information System (INIS)

Barrett, A.J.; Marquino, W.

2013-01-01

U.S. federal regulations require light water cooled nuclear power plants to cope with Station Blackout for a predetermined amount of time based on design factors for the plant. U.S. regulations define Station Blackout (SBO) as a loss of the offsite electric power system concurrent with turbine trip and unavailability of the onsite emergency AC power system. According to U.S. regulations, typically the coping period for an SBO is 4 hours and can be as long as 16 hours for currently operating BWR plants. Being able to cope with an SBO and loss of all AC power is required by international regulators as well. The U.S. licensing basis for the ESBWR is a coping period of 72 hours for an SBO based on U.S. NRC requirements for passive safety plants. In the event of an extended SBO (viz., greater than 72 hours), the ESBWR response shows that the design is able to cope with the event for at least 7 days without AC electrical power or operator action. ESBWR is a Generation III+ reactor design with an array of passive safety systems. The ESBWR primary success path for mitigation of an SBO event is the Isolation Condenser System (ICS). The ICS is a passive, closed loop, safety system that initiates automatically on a loss of power. Upon Station Blackout or loss of all AC power, the ICS begins removing decay heat from the Reactor Pressure Vessel (RPV) by (i) condensing the steam into water in heat exchangers located in pools of water above the containment, and (ii) transferring the decay heat to the atmosphere. The condensed water is then returned by gravity to cool the reactor again. The ICS alone is capable of maintaining the ESBWR in a safe shutdown condition after an SBO for an extended period. The fuel remains covered throughout the SBO event. The ICS is able to remove decay heat from the RPV for at least 7 days and maintains the reactor in a safe shutdown condition. The water level in the RPV remains well above the top of active fuel for the duration of the SBO event

Relap5 Analysis of Processes in Reactor Cooling Circuit and Reactor Cavity in Case of Station Blackout in RBMK-1500

International Nuclear Information System (INIS)

Kaliatka, A.

2007-01-01

Ignalina NPP is equipped with channel-type boiling-water graphite-moderated reactor RBMK-1500. Results of the level-1 probabilistic safety assessment of the Ignalina NPP have shown that in topography of the risk, the transients with failure of long-term core cooling other than LOCA are the main contributors to the core damage frequency. The total loss of off-site power with a failure to start any diesel generator, that is station blackout, is the event which could lead to the loss of long-term core cooling. Such accident could lead to multiple ruptures of fuel channels with severe consequences and should be analyzed in order to estimate the timing of the key events and the possibilities for accident management. This paper presents the results of the analysis of station blackout at Ignalina NPP. Analysis was performed using thermal-hydraulic state-of-the-art RELAP5/MOD3.2 code. The response of reactor cooling system and the processes in the reactor cavity and its venting system in case of a few fuel-channel ruptures due to overheating were demonstrated. The possible measures for prevention of the development of this beyond design basis accident (BDBA) to a severe accident are discussed

Light Water Reactor Sustainability Program: Analysis of Pressurized Water Reactor Station Blackout Caused by External Flooding Using the RISMC Toolkit

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cogliati, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinoshita, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-08-01

The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impact of these factors on the safety of the plant, the Risk Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This report focuses, in particular, on the application of a RISMC detailed demonstration case study for an emergent issue using the RAVEN and RELAP-7 tools. This case study looks at the impact of a couple of challenges to a hypothetical pressurized water reactor, including: (1) a power uprate, (2) a potential loss of off-site power followed by the possible loss of all diesel generators (i.e., a station black-out event), (3) and earthquake induces station-blackout, and (4) a potential earthquake induced tsunami flood. The analysis is performed by using a set of codes: a thermal-hydraulic code (RELAP-7), a flooding simulation tool (NEUTRINO) and a stochastic analysis tool (RAVEN) – these are currently under development at the Idaho National Laboratory.

The Rising Frequency of IT Blackouts Indicates the Increasing Relevance of IT Emergency Concepts to Ensure Patient Safety.

Science.gov (United States)

Sax, Ulrich; Lipprandt, M; Röhrig, R

2016-11-10

As many medical workflows depend vastly on IT support, great demands are placed on the availability and accuracy of the applications involved. The cases of IT failure through ransomware at the beginning of 2016 are impressive examples of the dependence of clinical processes on IT. Although IT risk management attempts to reduce the risk of IT blackouts, the probability of partial/total data loss, or even worse, data falsification, is not zero. The objective of this paper is to present the state of the art with respect to strategies, processes, and governance to deal with the failure of IT systems. This article is conducted as a narrative review. Worst case scenarios are needed, dealing with methods as to how to survive the downtime of clinical systems, for example through alternative workflows. These workflows have to be trained regularly. We categorize the most important types of IT system failure, assess the usefulness of classic counter measures, and state that most risk management approaches fall short on exactly this matter. To ensure that continuous, evidence-based improvements to the recommendations for IT emergency concepts are made, it is essential that IT blackouts and IT disasters are reported, analyzed, and critically discussed. This requires changing from a culture of shame and blame to one of error and safety in healthcare IT. This change is finding its way into other disciplines in medicine. In addition, systematically planned and analyzed simulations of IT disaster may assist in IT emergency concept development.

Plant habitability assessment for Point Lepreau Generating Station during a severe accident resulting from station blackout conditions

International Nuclear Information System (INIS)

Mullin, D.

2015-01-01

In response to the CNSC Fukushima Action Plan, the CANDU Owners Group (COG) developed a methodology for assessing nuclear power plant habitability under Joint Project 4426 and to determine if any improvement actions are necessary to provide a high degree of assurance that a severe accident can be managed from a human and organizational performance perspective. NB Power has applied the methodology considering a station black-out scenario (representative case), and assessed the effects of non-radiological hazards and radiological hazards in the context of operator dose relative to emergency dose limits. The paper will discuss the overall methodology, findings and recommendations. (author)

Plant habitability assessment for Point Lepreau Generating Station during a severe accident resulting from station blackout conditions

Energy Technology Data Exchange (ETDEWEB)

Mullin, D., E-mail: dmullin@nbpower.com [New Brunswick Power Corporation, Point Lepreau Generating Station, Lepreau, NB (Canada)

2015-07-01

In response to the CNSC Fukushima Action Plan, the CANDU Owners Group (COG) developed a methodology for assessing nuclear power plant habitability under Joint Project 4426 and to determine if any improvement actions are necessary to provide a high degree of assurance that a severe accident can be managed from a human and organizational performance perspective. NB Power has applied the methodology considering a station black-out scenario (representative case), and assessed the effects of non-radiological hazards and radiological hazards in the context of operator dose relative to emergency dose limits. The paper will discuss the overall methodology, findings and recommendations. (author)

Light Water Reactor Sustainability Program: Analysis of Pressurized Water Reactor Station Blackout caused by external flooding using the RISMC toolkit

International Nuclear Information System (INIS)

2014-01-01

The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impacts of these two factors on the safety of the plant, the Risk Informed Safety Margin Characterization project aims to provide insights to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This paper focuses on the impacts of power uprate on the safety margin of a boiling water reactor for a flooding induced station black-out event. Analysis is performed by using a combination of thermal-hydraulic codes and a stochastic analysis tool currently under development at the Idaho National Laboratory, i.e. RAVEN. We employed both classical statistical tools, i.e. Monte-Carlo, and more advanced machine learning based algorithms to perform uncertainty quantification in order to quantify changes in system performance and limitations as a consequence of power uprate. Results obtained give a detailed investigation of the issues associated with a plant power uprate including the effects of station black-out accident scenarios. We were able to quantify how the timing of specific events was impacted by a higher nominal reactor core power. Such safety insights can provide useful information to the decision makers to perform risk informed margins management.

Station Blackout Analysis of HTGR-Type Experimental Power Reactor

Science.gov (United States)

Syarip; Zuhdi, Aliq; Falah, Sabilul

2018-01-01

The National Nuclear Energy Agency of Indonesia has decided to build an experimental power reactor of high-temperature gas-cooled reactor (HTGR) type located at Puspiptek Complex. The purpose of this project is to demonstrate a small modular nuclear power plant that can be operated safely. One of the reactor safety characteristics is the reliability of the reactor to the station blackout (SBO) event. The event was observed due to relatively high disturbance frequency of electricity network in Indonesia. The PCTRAN-HTR functional simulator code was used to observe fuel and coolant temperature, and coolant pressure during the SBO event. The reactor simulated at 10 MW for 7200 s then the SBO occurred for 1-3 minutes. The analysis result shows that the reactor power decreases automatically as the temperature increase during SBO accident without operator’s active action. The fuel temperature increased by 36.57 °C every minute during SBO and the power decreased by 0.069 MW every °C fuel temperature rise at the condition of anticipated transient without reactor scram. Whilst, the maximum coolant (helium) temperature and pressure are 1004 °C and 9.2 MPa respectively. The maximum fuel temperature is 1282 °C, this value still far below the fuel temperature limiting condition i.e. 1600 °C, its mean that the HTGR has a very good inherent safety system.

Extended Station Blackout Analysis for VVER-1000 MWe Reactor

Energy Technology Data Exchange (ETDEWEB)

Gaikwad, A. J.; Rao, R. S.; Lakshmanan, S. P.; Gupta, A., E-mail: avinashg@aerb.gov.in [Atomic Energy Regulatory Board, Mumbai (India)

2014-10-15

Post Fukushima, the plant behaviour for an extended station black-out (ESBO) scenario with only passive system availability for about 7 days has become imperative. Thermal hydraulic analysis of ESBO with the availability of passive heat removal system (PHRS), passive first stage and second stage hydro accumulators were carried out to demonstrate the design capabilities. Two different cases having primary leak rates of 2.2 tons/hr and 6.6 tons/hr were analyzed to study sustenance of natural circulation. For the study, out of 4 PHRS trains, one PHRS train was assumed to be in failure mode. The objective here is to predict the core cooling capability for a period of 7 days under ESBO conditions with the available water inventories from first and second stage hydroaccumulators only. Over simplified energy balance studies cannot ascertain sustenance of natural circulation in the primary system, steam generators (SGs) and PHRS. The analysis was carried out by using system thermal hydraulic safety code RELAP5/SCDAP/MOD 3.4. It is inferred that the inventory in the first stage accumulators and second stage accumulators compensate the leak and decay heat is removed effectively with the help of passive heat removal systems. It is also observed that even after 7 days of ESBO a large inventory is still available in the second stage accumulators and the primary system remains subcooled. (author)

Out of the Blackout and into the Light: How the Arts Survived Pinochet’s Dictatorship

Directory of Open Access Journals (Sweden)

Paula Thorrington Cronovich

2014-06-01

This article shows how various artists segued out of the cultural blackout of the late seventies and into a phase of surprising artistic production during the military regime in Chile. At a time when political parties were banned and public gatherings considered illegal, Chileans found alternative ways to oppose the military government. In this climate, I argue that artistic expression took on political meaning. The fact that the “No” Campaign of 1988 was able to oust the dictator with an optimistic message of joy and hope, attests to the point that Chileans were able to shed their fears and change their outlook. Throughout the decade, the arts—innovations in poetry, music, theater, narrative and the audiovisual media—had offered people a much-needed forum for expression.

Contributions of the restructuring of the electric power industry to the August 14, 2003 blackout

International Nuclear Information System (INIS)

Casazza, J.; Delea, F.; Loehr, G.

2005-01-01

A review of the roles of industry and government in the 2003 blackout was presented. This white paper was prepared by a group of engineers with high level experience in the electric power industry who are concerned that deregulation of the industry has led to a significant decrease in reliability. It was noted that post-blackout reviews have focused on technical failures instead of examining the responsibilities and failures of the National Electric Reliability Council (NERC). Deficiencies in the analytical capabilities of control centres were discussed, as well as issues concerning communication protocols and training. Deregulation and the concomitant restructuring of the electric power industry has led to a shift from long term optimization, inter-system coordination and reliability towards dependence on immediate profits. In addition, there have been significant reductions in personnel at electric power organizations and companies, as well as increasing complexity in operations. Increased complexity has resulted in a dilution of management responsibility, as well as over-reliance on markets to solve scientifically complex problems. There have also been cutbacks in training and research. The functional separation of generation and transmission within companies has contributed to the diffusion of best technical knowledge. Many private utilities have divested their generation resources in response to regulatory pressures. The entrance of merchant power plants in the power system has led to the establishment of new market areas that are inconsistent with the boundaries of responsible operating entities. It was concluded that all these changes have created a more complicated and compartmentalized industry structure. Decisions are now made by a large number of entities, most of which are competitors and each of which has more interest in profit than in bulk power system reliability. Procedural rules established between and among the various parties are no longer

Analysis of core uncovery time in Kuosheng station blackout transient with MELCOR

International Nuclear Information System (INIS)

Wang, S.J.; Chien, C.S.

1996-01-01

The MELCOR code, developed by the Sandia National Laboratories, is capable of simulating severe accident phenomena of nuclear power plants. Core uncovery time is an important parameter in the probabilistic risk assessment. However, many MELCOR users do not generate the initial conditions in a station blackout (SBO) transient analysis. Thus, achieving reliable core uncovery time is difficult. The core uncovery time for the Kuosheng nuclear power plant during an SBO transient is analyzed. First, full-power steady-state conditions are generated with the application of a developed self-initialization algorithm. Then the response of the SBO transient up to core uncovery is simulated. The effects of key parameters including the initialization process and the reactor feed pump (RFP) coastdown time on the core uncovery time are analyzed. The initialization process is the most important parameter that affects the core uncovery time. Because SBO transient analysis, the correct initial conditions must be generated to achieve a reliable core uncovery time. The core uncovery time is also sensitive to the RFP coastdown time. A correct time constant is required

Can the complex networks help us in the resolution of the problem of power outages (blackouts) in Brazil?

Energy Technology Data Exchange (ETDEWEB)

Castro, Paulo Alexandre de; Souza, Thaianne Lopes de [Universidade Federal de Goias (UFG), Catalao, GO (Brazil)

2011-07-01

Full text. What the Brazilian soccer championship, Hollywood actors, the network of the Internet, the spread of viruses and electric distribution network have in common? Until less than two decade ago, the answer would be 'nothing' or 'almost nothing'. However, the answer today to this same question is 'all' or 'almost all'. The answer to these questions and more can be found through a sub-area of statistical physics | called science of complex networks that has been used to approach and study the most diverse natural and non-natural systems, such as systems/social networks, information, technological or biological. In this work we study the distribution network of electric power in Brazil (DEEB), from a perspective of complex networks, where we associate stations and/or substations with a network of vertices and the links between the vertices we associate with the transmission lines. We are doing too a comparative study with the best-known models of complex networks, such as Erdoes-Renyi, Configuration Model and Barabasi-Albert, and then we compare with results obtained in real electrical distribution networks. Based on this information, we do a comparative analysis using the following variables: connectivity distribution, diameter, clustering coefficient, which are frequently used in studies of complex networks. We emphasize that the main objective of this study is to analyze the robustness of the network DEEB, and then propose alternatives for network connectivity, which may contribute to the increase of robustness in maintenance projects and/or expansion of the network, in other words our goal is to make the network to proof the blackouts or improve the endurance the network against the blackouts. For this purpose, we use information from the structural properties of networks, computer modeling and simulation. (author)

Development and qualification of a thermal-hydraulic nodalization for modeling station blackout accident in PSB-VVER test facility

Energy Technology Data Exchange (ETDEWEB)

Saghafi, Mahdi [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); Ghofrani, Mohammad Bagher, E-mail: ghofrani@sharif.edu [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); D’Auria, Francesco [San Piero a Grado Nuclear Research Group (GRNSPG), University of Pisa, Via Livornese 1291, San Piero a Grado, Pisa (Italy)

2016-07-15

Highlights: • A thermal-hydraulic nodalization for PSB-VVER test facility has been developed. • Station blackout accident is modeled with the developed nodalization in MELCOR code. • The developed nodalization is qualified at both steady state and transient levels. • MELCOR predictions are qualitatively and quantitatively in acceptable range. • Fast Fourier Transform Base Method is used to quantify accuracy of code predictions. - Abstract: This paper deals with the development of a qualified thermal-hydraulic nodalization for modeling Station Black-Out (SBO) accident in PSB-VVER Integral Test Facility (ITF). This study has been performed in the framework of a research project, aiming to develop an appropriate accident management support tool for Bushehr nuclear power plant. In this regard, a nodalization has been developed for thermal-hydraulic modeling of the PSB-VVER ITF by MELCOR integrated code. The nodalization is qualitatively and quantitatively qualified at both steady-state and transient levels. The accuracy of the MELCOR predictions is quantified in the transient level using the Fast Fourier Transform Base Method (FFTBM). FFTBM provides an integral representation for quantification of the code accuracy in the frequency domain. It was observed that MELCOR predictions are qualitatively and quantitatively in the acceptable range. In addition, the influence of different nodalizations on MELCOR predictions was evaluated and quantified using FFTBM by developing 8 sensitivity cases with different numbers of control volumes and heat structures in the core region and steam generator U-tubes. The most appropriate case, which provided results with minimum deviations from the experimental data, was then considered as the qualified nodalization for analysis of SBO accident in the PSB-VVER ITF. This qualified nodalization can be used for modeling of VVER-1000 nuclear power plants when performing SBO accident analysis by MELCOR code.

Benchmarking Simulation of Long Term Station Blackout Events

International Nuclear Information System (INIS)

Kim, Sung Kyum; Lee, John C.; Fynan, Douglas A.; Lee, John C.

2013-01-01

The importance of passive cooling systems has emerged since the SBO events. Turbine-driven auxiliary feedwater (TD-AFW) system is the only passive cooling system for steam generators (SGs) in current PWRs. During SBO events, all alternating current (AC) and direct current (DC) are interrupted and then the water levels of steam generators become high. In this case, turbine blades could be degraded and cannot cool down the SGs anymore. To prevent this kind of degradations, improved TD-AFW system should be installed for current PWRs, especially OPR 1000 plants. A long-term station blackout (LTSBO) scenario based on the improved TD-AFW system has been benchmarked as a reference input file. The following task is a safety analysis in order to find some important parameters causing the peak cladding temperature (PCT) to vary. This task has been initiated with the benchmarked input deck applying to the State-of-the-Art Reactor Consequence Analyses (SOARCA) Report. The point of the improved TD-AFW is to control the water level of the SG by using the auxiliary battery charged by a generator connected with the auxiliary turbine. However, this battery also could be disconnected from the generator. To analyze the uncertainties of the failure of the auxiliary battery, the simulation for the time-dependent failure of the TD-AFW has been performed. In addition to the cases simulated in the paper, some valves (e. g., pressurizer safety valve), available during SBO events in the paper, could be important parameters to assess uncertainties in PCTs estimated. The results for these parameters will be included in a future study in addition to the results for the leakage of the RCP seals. After the simulation of several transient cases, alternating conditional expectation (ACE) algorithm will be used to derive functional relationships between the PCT and several system parameters

Test study on safety features of station blackout accident for nuclear main pump

International Nuclear Information System (INIS)

Liu Xiajie; Wang Dezhong; Zhang Jige; Liu Junsheng; Yang Zhe

2009-01-01

The theoretical and experimental studies of reactor coolant pump accidents encountered nation-wide and world-wide were described. To investigate the transient hydrodynamic performance of reactor coolant pump (RCP) during the period of rotational inertia in the station blackout accident, some theoretical and experimental studies were carried out, and the analysis of the test results was presented. The experiment parameters, conditions and test methods were introduced. The flow-rate, rotate speed and vibrations were analyzed emphatically. The quadruplicate polynomial curve equation was used to simulate the flow-rate,rotate speed along with time. The test results indicate that the flow-rate and rotator speed decrease rapidly at the very beginning of cut power and the test results accord with the regulation of safety standard. The vibrant displacement of bearing seat is intensified at the moment of lose power, but after a certain period rotor shaft libration changes. The test and analysis results help to understand the hydrodynamic performance of nuclear primary pump under lost of power accident, and provide the basic reference for safety evaluation. (authors)

Case Study of Multi-Unit Risk: Multi-Unit Station Black-Out

Energy Technology Data Exchange (ETDEWEB)

Oh, Kyemin; Jang, Seung-cheol [KAERI, Daejeon (Korea, Republic of); Heo, Gyunyoung [Kyung Hee University, Yongin (Korea, Republic of)

2015-05-15

After Fukushima Daiichi Accident, importance and public concern for Multi-Unit Risk (MUR) or Probabilistic Safety Assessment (PSA) have been increased. Most of nuclear power plant sites in the world have more than two units. These sites have been facing the problems of MUR or accident such as Fukushima. In case of South Korea, there are generally more than four units on the same site and even more than ten units are also expected. In other words, sites in South Korea also have been facing same problems. Considering number of units on the same site, potential of these problems may be larger than other countries. The purpose of this paper is to perform case study based on another paper submitted in the conference. MUR is depended on various site features such as design, shared systems/structures, layout, environmental condition, and so on. Considering various dependencies, we assessed Multi-Unit Station Black-out (MSBO) accident based on Hanul Unit 3 and 4 model. In this paper, case study for multi-unit risk or PSA had been performed. Our result was incomplete to assess total multi-unit risk because of two challenging issues. First, economic impact had not been evaluated to estimate multi-unit risk. Second, large uncertainties were included in our result because of various assumptions. These issues must be resolved in the future.

Case Study of Multi-Unit Risk: Multi-Unit Station Black-Out

International Nuclear Information System (INIS)

Oh, Kyemin; Jang, Seung-cheol; Heo, Gyunyoung

2015-01-01

After Fukushima Daiichi Accident, importance and public concern for Multi-Unit Risk (MUR) or Probabilistic Safety Assessment (PSA) have been increased. Most of nuclear power plant sites in the world have more than two units. These sites have been facing the problems of MUR or accident such as Fukushima. In case of South Korea, there are generally more than four units on the same site and even more than ten units are also expected. In other words, sites in South Korea also have been facing same problems. Considering number of units on the same site, potential of these problems may be larger than other countries. The purpose of this paper is to perform case study based on another paper submitted in the conference. MUR is depended on various site features such as design, shared systems/structures, layout, environmental condition, and so on. Considering various dependencies, we assessed Multi-Unit Station Black-out (MSBO) accident based on Hanul Unit 3 and 4 model. In this paper, case study for multi-unit risk or PSA had been performed. Our result was incomplete to assess total multi-unit risk because of two challenging issues. First, economic impact had not been evaluated to estimate multi-unit risk. Second, large uncertainties were included in our result because of various assumptions. These issues must be resolved in the future

Analysis of economics and safety to cope with station blackout in PWR

International Nuclear Information System (INIS)

Al Shehhi, Ahmed Saeed; Chang, Soon Heung; Kim, Sang Ho; Kang, Hyun Gook

2013-01-01

Highlights: • Proposed framework covers all aspects of very complicated decision making. • We addressed the various options against SBO. • Emergency water supply through the steam generator hookup was considered. • Optimal testing interval of EDG was determined in various design options. • Effect of risk aversion factor on decision making was quantitatively illustrated. - Abstract: Design and operation options that can reduce both the initiating event frequency and the accident mitigation probability were addressed in an integrated framework to cope with station blackout. The safety, engineering cost, water delivery cost and testing/maintenance cost of each option were quantitatively evaluated to calculate the cost variation and to find an optimal point in the reference reactor, OPR1000. Design variables that represent additional emergency water supply, diverse emergency diesel generator, and surveillance test period modification were investigated. Based on these design variables, we applied the developed formula to quantify cost items, which were presented as changes of the economics and the safety. A case study was provided to illustrate the change of the total cost. Different risk aversion factors that represent different attitudes of the public were also investigated. The result shows that the costs and benefits of various complicated options can be effectively addressed with the proposed risk-informed decision making framework

The integrity of NSSS and containment during extended station blackout for Kuosheng BWR plant

Energy Technology Data Exchange (ETDEWEB)

Hsu, Keng-Hsien; Yuann, Yng-Ruey; Lin, Ansheng [Atomic Energy Council, Taoyuan City, Taiwan (China). Inst. of Nuclear Energy Research

2017-11-15

The Fukushima Daiichi accident occurring on March 11, 2011, reveals that Station Blackout (SBO) may last longer than 8 h. However, the original design may not have sufficient capacity to cope with a SBO for more than 8 h. In view of this, Taiwan Power Company has initiated several enhancements to mitigate the severity of the extended SBO. Based on the improved plant configuration, a SBO coping analysis is performed in this study to assess whether the Kuosheng BWR plant has sufficient capability to cope with SBO for 24 h with respect to maintaining the integrity of the reactor core and containment. The analyses in the Nuclear Steam Supply System (NSSS) and the containment are based on the RETRAN-3D and GOTHIC models, respectively. The flow conditions calculated by RETRAN-3D during the event are retrieved and input to the GOTHIC containment model to determine the containment pressure and temperature response. These boundary conditions include SRV flow rate, SRV flow enthalpy, and total reactor coolant system leakage flow rate.

The integrity of NSSS and containment during extended station blackout for Kuosheng BWR plant

International Nuclear Information System (INIS)

Hsu, Keng-Hsien; Yuann, Yng-Ruey; Lin, Ansheng

2017-01-01

The Fukushima Daiichi accident occurring on March 11, 2011, reveals that Station Blackout (SBO) may last longer than 8 h. However, the original design may not have sufficient capacity to cope with a SBO for more than 8 h. In view of this, Taiwan Power Company has initiated several enhancements to mitigate the severity of the extended SBO. Based on the improved plant configuration, a SBO coping analysis is performed in this study to assess whether the Kuosheng BWR plant has sufficient capability to cope with SBO for 24 h with respect to maintaining the integrity of the reactor core and containment. The analyses in the Nuclear Steam Supply System (NSSS) and the containment are based on the RETRAN-3D and GOTHIC models, respectively. The flow conditions calculated by RETRAN-3D during the event are retrieved and input to the GOTHIC containment model to determine the containment pressure and temperature response. These boundary conditions include SRV flow rate, SRV flow enthalpy, and total reactor coolant system leakage flow rate.

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.

Simulation with the MELCOR code of two severe accident sequences, Station Blackout and Small Break LOCA, for the Atucha I nuclear power plant

International Nuclear Information System (INIS)

Valle Cepero, Reinaldo

2004-01-01

The results of the PSA-I applied to the Atucha I nuclear power plant (CNA I) determine the accidental sequences with the most influence related to the probability of the core reactor damage. Among those sequences are include, the Station Blackout and lost of primary coolant, combine with the failure of the emergency injection systems by pipe breaks of diameters between DN100 - DN25 or equivalent areas, Small LOCA. This paper has the objective to model and analyze the behavior of the primary circuit and the pressure vessel during the evolution of those two accidental sequences. It presented a detailed analysis of the main phenomena that occur from the initial moment of the accident to the failure moment of the pressure vessel and the melt material fall to the reactor cavity. Two sequences were taken into account, considering the main phenomena (core uncover, heating, fuel element oxidation, hydrogen generation, degradation and relocation of the melt material, failure of the support structures, etc.) and the time of occurrence, of those events will be different, if it is considered that both sequences will be developed in different scenarios. One case is an accident with the primary circuit to a high pressure (Station Blackout scenario) and the other with a early primary circuit depressurization due to the lost of primary coolant. For this work the MELCOR 1.8.5 code was used and it allows within a unified framework to modeling an extensive spectrum of phenomenology associated with the severe accidents. (author)

Emergent transformation games: exploring social innovation agency and activation through the case of the Belgian electricity blackout threat

Directory of Open Access Journals (Sweden)

Bonno Pel

2016-06-01

Full Text Available The persistence of current societal problems has given rise to a quest for transformative social innovations. As social innovation actors seek to become change makers, it has been suggested that they need to play into impactful macrodevelopments or "game-changers". Here, we aim to deepen the understanding of the social innovation agency in these transformation games. We analyze assumptions about the game metaphor, invoking insights from actor-network theory. The very emergence of transformation games is identified as a crucial but easily overlooked issue. As explored through the recent electricity blackout threat in Belgium, some current transformation games are populated with largely passive players. This illustrative case demonstrates that socially innovative agency cannot be presupposed. In some transformation games, the crucial game-changing effect is to start the game by activating the players.

Mitigating fuel handling situations during station blackout in TAPP-3 and

International Nuclear Information System (INIS)

Chugh, V.K.; Roy, Shibaji; Gupta, H.; Inder Jit

2002-01-01

Full text: On power refueling is one of the important features of PHWRs. fuelling machine (FM) Head becomes part of the reactor pressure boundary during refueling operations. Hot irradiated (spent) fuel bundles are received in the FM Head from the Reactor and transferred to spent fuel storage bay (SFSB). These bundles pass through various fuel handling (FH) Equipment under submerged condition except during the dry transfer operation. Situations of station blackout (SBO) i.e. postulated simultaneous failure of Class III and Class IV electric power, could persist for a long period, during on-reactor or off-reactor FH operations, with the spent fuel bundles being any where in the system between the reactor and SFSB. The cooling provisions for the spent fuel bundles vary depending upon the stage of operation. During SBO, it becomes difficult to maintain cooling to these fuel bundles due to the limited availability of Class II power and instrument air. However, cooling is essential, to ensure the safety of the bundles. As discussed in the paper, safety of these fuel bundles in the system and/or for those lying in the liner tube region of the reactor end fitting is ensured, during SBO, by resorting to passive means like stay-put, gravity- fill, D 2 O-steaming etc. for cooling the bundles. Various scenarios have been identified for cooling provisions of the bundles in the system. The paper also describes consequences like loss of D 2 O inventory, rise in ambient temperature and pressure and tritium build-up in Reactor Building, emanating from these cooling schemes

A portable backup power supply to assure extended decay heat removal during natural phenomena-induced station blackout

International Nuclear Information System (INIS)

Proctor, L.D.; Merryman, L.D.; Sallee, W.E.

1989-01-01

The High Flux Isotope Reactor (HFIR) is a light water cooled and moderated flux-trap type research reactor located at Oak Ridge National Laboratory (ORNL). Coolant circulation following reactor shutdown is provided by the primary coolant pumps. DC-powered pony motors drive these pumps at a reduced flow rate following shutdown of the normal ac-powered motors. Forced circulation decay heat removal is required for several hours to preclude core damage following shutdown. Recent analyses identified a potential vulnerability due to a natural phenomena-induced station blackout. Neither the offsire power supply nor the onsite emergency diesel generators are designed to withstand the effects of seismic events or tornadoes. It could not be assured that the capacity of the dedicated batteries provided as a backup power supply for the primary coolant pump pony motors is adequate to provide forced circulation cooling for the required time following such events. A portable backup power supply added to the plant to address this potential vulnerability is described

Study of a Station Blackout Event in the PWR Plant

International Nuclear Information System (INIS)

Ching-Hui Wu; Tsu-Jen Lin; Tsu-Mu Kao

2002-01-01

On March 18, 2001, a PWR nuclear power plant located in the Southern Taiwan occurred a Station Blackout (SBO) event. Monsoon seawater mist caused the instability of offsite power grids. High salt-contained mist caused offsite power supply to the nuclear power plant very unstable, and forced the plant to be shutdown. Around 24 hours later, when both units in the plant were shutdown, several inadequate high cycles of bus transfer between 345 kV and 161 kV startup transformers degraded the emergency 4.16 kV switchgears. Then, in the Train-A switchgear room of Unit 1 occurred a fire explosion, when the degraded switchgear was hot shorted at the in-coming 345 kV breaker. Inadequate configuration arrangement of the offsite power supply to the emergency 4.16 kV switchgears led to loss of offsite power (LOOP) events to both units in the plant. Both emergency diesel generators (EDG) of Unit 1 could not be in service in time, but those of Unit 2 were running well. The SBO event of Unit 1 lasted for about two hours till the fifth EDG (DG-5) was lined-up to the Train-B switchgear. This study investigated the scenario of the SBO event and evaluated a risk profile for the SBO period. Guidelines in the SBO event, suggested by probabilistic risk assessment (PRA) procedures were also reviewed. Many related topics such as the re-configuration of offsite power supply, the addition of isolation breakers of the emergency 4.16 kV switchgears, the betterment of DG-5 lineup design, and enhancement of the reliability of offsite power supply to the PWR plant, etc., will be in further studies. (authors)

Investigation of a Station Blackout Scenario with the ATLAS Test

International Nuclear Information System (INIS)

Kim, Yeon Sik; Yu, Xin Guo; Kang, Kyoung Ho; Park, Hyun Sik; Cho, Seok; Min, Kyeong Ho; Choi, Nam Hyeon; Kim, Bok Deuk; Park, Jong Gook; Choi, Ki Yong

2012-01-01

KAERI (Korea Atomic Energy Research Institute) has been operating an integral effect test facility, ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation), for accident simulations pertaining to the OPR1000 (Optimized Power Reactor, 1000MWe) and the APR1400 (Advanced Power Reactor, 1400MWe) which are in operation and under construction in Korea, respectively. After the Fukushima accidents due to the combination of an earthquake followed by a tsunami in east Japan on March 11, 2011, the concept of boundary between the design basis and beyond-design basis accidents became obscure. One scenario is the station blackout (SBO), which is defined as 'the loss of all alternating current (AC) power in a nuclear power plant' by the USNRC 10CFR50 Section 50.63, which has adopted a new safety regulation for the SBO in June of 1988. In any case the SBO that occurred in Fukushima seemed to go beyond the definition of the current SBO scenario. In the mean time, numerous researches has been conducted on the safety concern of the SBO for existing and advanced nuclear power plants worldwide. From the internal review of an SBO scenario, it was concluded that the understanding of the thermo-hydraulic phenomena occurred within the reactor coolant system is a prerequisite although seemed to be quite a simple sequence of events. This was the motivation of an SBO test using the ATLAS facility. For the understanding of the physical phenomena within the primary system, an SBO was assumed with simple intial and boundary conditions, e.g. start of an SBO at time zero, no diesel and AC powers, no auxiliary feedwater pumps (motor-driven and turbine driven) etc. In this paper, overview of the SBO test results was described including a result of analytical calculations simulating the SBO test using the MARS code

Station Blackout Analysis for a 3-Loop Westinghouse PWR Reactor Using Trace

International Nuclear Information System (INIS)

El-Sahlamy, N.M.

2017-01-01

One of the main concerns in the area of severe accidents in nuclear reactors is that of station blackout (SBO). The loss of offsite electrical power concurrent with the unavailability of the onsite emergency alternating current (AC) power system can result in loss of decay heat removal capability, leading to a potential core damage which may lead to undesirable consequences to the public and the environment. To cope with an SBO, nuclear reactors are provided with protection systems that automatically shut down the reactor, and with safety systems to remove the core residual heat. This paper provides a best estimate assessment of the SBO scenario in a 3-loop Westinghouse PWR reactor. The evaluation is performed using TRACE, a best estimate computer code for thermal-hydraulic calculations. Two sets of scenarios for SBO analyses are discussed in the current work. The first scenario is the short term SBO where it is assumed that in addition to the loss of AC power, there is no DC power; i.e., no batteries are available. In the second scenario, a long term SBO is considered. For this scenario, DC batteries are available for four hours. The aim of the current SBO analyses for the 3-loop pressurized water reactor presented in this paper is to focus on the effect of the availability of a DC power source to delay the time to core uncovers and heatup

Utilities must leverage existing resources and upgrade technology to avoid future blackouts

International Nuclear Information System (INIS)

Masiello, R.

2004-01-01

The blackout of August 14, 2003 is used as the incentive to examine transmission grid reliability, expose its deficiencies in terms of technology, standards and processes used to manage reliability, and to make recommendations for leveraging existing resources and upgrading both the technology and procedures to avoid similar breakdowns in the future. It is recommended that in the area of monitoring transmission grid reliability utilities should borrow a page from the Enterprise Risk Management Practices of the financial industry by adopting a system which looks beyond the first 'credible' contingency (the current system) and examine many more 'incredible' contingencies, and underlying events that can trigger multiple contingencies, and plan for them in their operations. Utility companies are also urged to upgrade their energy management systems (EMS) technology to be able to deal with the kinds of severely depressed voltages and overloaded circuits that many grids experience today. Investment in new capabilities in control rooms, more and better communications will be essential. EMS algorithms and models must be upgraded to operate under a broader spectrum of grid conditions and to simulate the once-in-a-lifetime outage scenarios that most operators believe could never strike their utility. Expert opinion strongly suggests that as part of this process of upgrading, contingency analysis should shift from the 'N-1' model of the present to a stochastic model that considers a wider range of possible events in a probabilistic framework

Utilities must leverage existing resources and upgrade technology to avoid future blackouts

Energy Technology Data Exchange (ETDEWEB)

Masiello, R. [KEMA Inc. Burlington, MA (United States)

2004-06-01

The blackout of August 14, 2003 is used as the incentive to examine transmission grid reliability, expose its deficiencies in terms of technology, standards and processes used to manage reliability, and to make recommendations for leveraging existing resources and upgrading both the technology and procedures to avoid similar breakdowns in the future. It is recommended that in the area of monitoring transmission grid reliability utilities should borrow a page from the Enterprise Risk Management Practices of the financial industry by adopting a system which looks beyond the first 'credible' contingency (the current system) and examine many more 'incredible' contingencies, and underlying events that can trigger multiple contingencies, and plan for them in their operations. Utility companies are also urged to upgrade their energy management systems (EMS) technology to be able to deal with the kinds of severely depressed voltages and overloaded circuits that many grids experience today. Investment in new capabilities in control rooms, more and better communications will be essential. EMS algorithms and models must be upgraded to operate under a broader spectrum of grid conditions and to simulate the once-in-a-lifetime outage scenarios that most operators believe could never strike their utility. Expert opinion strongly suggests that as part of this process of upgrading, contingency analysis should shift from the 'N-1' model of the present to a stochastic model that considers a wider range of possible events in a probabilistic framework.

Comparison of oxide- and metal-core behavior during CRBRP [Clinch River Breeder Reactor Plant] station blackout

International Nuclear Information System (INIS)

Polkinghorne, S.T.; Atkinson, S.A.

1986-01-01

A resurrected concept that could significantly improve the inherently safe response of Liquid-Metal cooled Reactors (LMRs) during severe undercooling transients is the use of metallic fuel. Analytical studies have been reported on for the transient behavior of metal-fuel cores in innovative, inherently safe LMR designs. This paper reports on an analysis done, instead, for the Clinch River Breeder Reactor Plant (CRBRP) design with the only innovative change being the incorporation of a metal-fuel core. The SSC-L code was used to simulate a protected station blackout accident in the CRBRP with a 943 MWt Integral Fast Reactor (IFR) metal-fuel core. The results, compared with those for the oxide-fueled CRBRP, show that the margin to boiling is greater for the IFR core. However, the cooldown transient is more severe due to the faster thermal response time of metallic fuel. Some additional calculations to assess possible LMR design improvements (reduced primary system pressure losses, extended flow coastdown) are also discussed. 8 refs., 13 figs., 2 tabs

Swiss Solutions for Providing Electrical Power in Cases of Long-Term Black-Out of the Grid

International Nuclear Information System (INIS)

Altkind, Franz; Schmid, Daniel

2015-01-01

A better understanding of nuclear power plant electrical system robustness and defence-in-depth may be derived from comparing design and operating practices in member countries. In pursuing this goal, the current paper will focus on Switzerland. It will present in general the protective measures implemented in the Swiss nuclear power plants to ensure power supply, which comply with the 'Defence-in-depth' principle by means of several layers of protection. In particular it will present the measures taken in case of a total station blackout. The different layers supplying electricity may be summed up as follows. The first layer consists of the external main grid, which the plant generators feed into. The second layer is the auxiliary power supply when the power plant is in island mode in case of a failure of the main grid. A third layer is provided by the external reserve grid in case of both a failure of the external main grid and of the auxiliary power supply in island mode. As a fourth layer there exists an emergency electrical power supply. This is supplied either from an emergency diesel generator or a direct feed from a hydroelectric power plant. In the fifth layer, the special emergency electrical power supply from bunkered emergency diesel generators power the special emergency safety system and is activated upon the loss of all external feeds. A sixth layer consists of accident management equipment. Since the Fukushima event, the sixth layer has been reinforced and a seventh layer with off-site accident management equipment has been newly added. The Swiss nuclear safety regulator has analysed the accident. It reviewed the Swiss plants' protection against earthquakes as well as flooding and demanded increased precautionary measures from the Swiss operators in the hypothetical case of a total station blackout, when all the first five layers of supply would fail. In the immediate, a centralized storage with severe accident management equipment

Source term analysis in severe accident induced by large break loss of coolant accident coincident with ship blackout for ship reactor

International Nuclear Information System (INIS)

Zhang Yanzhao; Zhang Fan; Zhao Xinwen; Zheng Yingfeng

2013-01-01

Using MELCOR code, the accident analysis model was established for a ship reactor. The behaviors of radioactive fission products were analyzed in the case of severe accident induced by large break loss of coolant accident coincident with ship blackout. The research mainly focused on the behaviors of release, transport, retention and the final distribution of inert gas and CsI. The results show that 83.12% of inert gas releases from the core, and the most of inert gas exists in the containment. About 83.08% of CsI release from the core, 72.66% of which is detained in the debris and the primary system, and 27.34% releases into the containment. The results can give a reference for the evaluation of cabin dose and nuclear emergency management. (authors)

Assessment of the potential for high-pressure melt ejection resulting from a Surry station blackout transient

International Nuclear Information System (INIS)

Knudson, D.L.; Dobbe, C.A.

1993-11-01

Containment integrity could be challenged by direct heating associated with a high pressure melt ejection (HPME) of core materials following reactor vessel breach during certain severe accidents. Intentional reactor coolant system (RCS) depressurization, where operators latch pressurizer relief valves open, has been proposed as an accident management strategy to reduce risks by mitigating the severity of HPME. However, decay heat levels, valve capacities, and other plant-specific characteristics determine whether the required operator action will be effective. Without operator action, natural circulation flows could heat ex-vessel RCS pressure boundaries (surge line and hot leg piping, steam generator tubes, etc.) to the point of failure before vessel breach, providing an alternate mechanism for RCS depressurization and HPME mitigation. This report contains an assessment of the potential for HPME during a Surry station blackout transient without operator action and without recovery. The assessment included a detailed transient analysis using the SCDAP/RELAP5/MOD3 computer code to calculate the plant response with and without hot leg countercurrent natural circulation, with and without reactor coolant pump seal leakage, and with variations on selected core damage progression parameters. RCS depressurization-related probabilities were also evaluated, primarily based on the code results

Station blackout with failure of wired shutdown system for AHWR

International Nuclear Information System (INIS)

Srivastava, A.; Contractor, A.D.; Chatterjee, B.; Kumar, Rajesh

2015-01-01

Advanced Heavy Water Reactor (AHWR) is a vertical pressure tube type boiling light water cooled and heavy water moderated reactor. This reactor has several advance safety features. One of the important passive design features of this reactor is that the heat removal is achieved through natural circulation of primary coolant at all power level without primary coolant pumps. Station blackout (SBO) scenario has become very important in aftermath of Fukushima event. The existing reactor has to demonstrate that design features are sufficient to mitigate the scenario whereas the new reactor design are adding specific features to tackle such scenario for prolonged period. The present study demonstrates the design features of AHWR to mitigate the SBO scenario along with failure of wired shutdown system. SBO event leads to feed water pump trip and loss of condenser vacuum which in turn results into loss of feed water and turbine trip on low condenser vacuum signal. Stoppage of steam flow to the turbine and bypass to the condenser lead to bottling up of the system, causing MHT pressure to rise. In the absence of reactor scram, the pressure continues to rise. Isolation Condenser (IC) valve starts opening at a pressure of 7.65 MPa. The pressure continues to rise as IC system is designed for decay heat removal and reactor power is brought down to decay power level through Passive Poison Injection System (PPIS) when the pressure reaches 8.4 MPa. The analysis shows that the event do not lead to undesirable clad surface temperature rise due to reactor trip by PPIS and decay heat removal for prolonged time by IC system. Thermal hydraulic response of different parameters like pressure, temperatures, and flows in MHT system is analyzed for this scenario. Pressure during transient is found to be well below the system pressure criteria of 110% of design pressure. This analysis highlights the design robustness of AHWR. (author)

Long-Term Station Blackout Accident Analyses of a PWR with RELAP5/MOD3.3

Directory of Open Access Journals (Sweden)

Andrej Prošek

2013-01-01

Full Text Available Stress tests performed in Europe after accident at Fukushima Daiichi also required evaluation of the consequences of loss of safety functions due to station blackout (SBO. Long-term SBO in a pressurized water reactor (PWR leads to severe accident sequences, assuming that existing plant means (systems, equipment, and procedures are used for accident mitigation. Therefore the main objective was to study the accident management strategies for SBO scenarios (with different reactor coolant pumps (RCPs leaks assumed to delay the time before core uncovers and significantly heats up. The most important strategies assumed were primary side depressurization and additional makeup water to reactor coolant system (RCS. For simulations of long term SBO scenarios, including early stages of severe accident sequences, the best estimate RELAP5/MOD3.3 and the verified input model of Krško two-loop PWR were used. The results suggest that for the expected magnitude of RCPs seal leak, the core uncovery during the first seven days could be prevented by using the turbine-driven auxiliary feedwater pump and manually depressurizing the RCS through the secondary side. For larger RCPs seal leaks, in general this is not the case. Nevertheless, the core uncovery can be significantly delayed by increasing RCS depressurization.

Assessment of the potential for HPME during a station blackout in the Surry and Zion PWRS

International Nuclear Information System (INIS)

Knudson, D.L.; Bayless, P.D.; Dobbe, C.A.; Odar, F.

1994-01-01

The integrity of a PWR (pressurized water reactor) containment structure could be challenged by direct heating associated with a HPME (high pressure melt ejection) of core materials following reactor vessel lower head breach during certain severe accidents. Structural failure resulting from direct containment heating is a contributor to the risk of operating a PWR. Intentional RCS (reactor coolant system) depressurization, where operators latch pressurizer relief valves open, has been proposed as an accident management strategy to reduce those risks by mitigating the severity of the HPME. However, decay heat levels, valve capacities, and other plant-specific characteristics determine whether the required operator action will be effective. Without operator action, natural circulation flows could heat ex-vessel RCS pressure boundaries (surge line and hot leg piping, steam generator tubes, etc.) to the point of failure before failure of the lower head providing an unintentional mechanism for depressurization and HPME mitigation. This paper summarizes an assessment of RCS depressurization with respect to the potential for HPME during a station blackout in the Surry and Zion PWRs. The assessment included a detailed transient analysis using the SCDAP/RELAP5/MOD3 computer code and an evaluation of RCS depressurization-related probabilities primarily based on the code results

The Safety Assessment of OPR-1000 for Station Blackout Applying Combined Deterministic and Probabilistic Procedure

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong Gu; Ahn, Seung-Hoon; Cho, Dae-Hyung [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2015-05-15

This is termed station blackout (SBO). However, it does not generally include the loss of available AC power to safety buses fed by station batteries through inverters or by alternate AC sources. Historically, risk analysis results have indicated that SBO was a significant contributor to overall core damage frequency. In this study, the safety assessment of OPR-1000 nuclear power plant for SBO accident, which is a typical beyond design basis accident and important contributor to overall plant risk, is performed by applying the combined deterministic and probabilistic procedure (CDPP). In addition, discussions are made for reevaluation of SBO risk at OPR-1000 by eliminating excessive conservatism in existing PSA. The safety assessment of OPR-1000 for SBO accident, which is a typical BDBA and significant contributor to overall plant risk, was performed by applying the combined deterministic and probabilistic procedure. However, the reference analysis showed that the CDF and CCDP did not meet the acceptable risk, and it was confirmed that the SBO risk should be reevaluated. By estimating the offsite power restoration time appropriately, the SBO risk was reevaluated, and it was finally confirmed that current OPR-1000 system lies in the acceptable risk against the SBO. In addition, it was demonstrated that the proposed CDPP is applicable to safety assessment of BDBAs in nuclear power plants without significant erosion of the safety margin.

Modeling and analysis of selected organization for economic cooperation and development PKL-3 station blackout experiments using TRACE

Directory of Open Access Journals (Sweden)

Roman Mukin

2018-04-01

Full Text Available A series of tests dedicated to station blackout (SBO accident scenarios have been recently performed at the Primärkreislauf-Versuchsanlage (primary coolant loop test facility; PKL facility in the framework of the OECD/NEA PKL-3 project. These investigations address current safety issues related to beyond design basis accident transients with significant core heat up. This work presents a detailed analysis using the best estimate thermal–hydraulic code TRACE (v5.0 Patch4 of different SBO scenarios conducted at the PKL facility; failures of high- and low-pressure safety injection systems together with steam generator (SG feedwater supply are considered, thus calling for adequate accident management actions and timely implementation of alternative emergency cooling procedures to prevent core meltdown. The presented analysis evaluates the capability of the applied TRACE model of the PKL facility to correctly capture the sequences of events in the different SBO scenarios, namely the SBO tests H2.1, H2.2 run 1 and H2.2 run 2, including symmetric or asymmetric secondary side depressurization, primary side depressurization, accumulator (ACC injection in the cold legs and secondary side feeding with mobile pump and/or primary side emergency core coolant injection from the fuel pool cooling pump. This study is focused specifically on the prediction of the core exit temperature, which drives the execution of the most relevant accident management actions. This work presents, in particular, the key improvements made to the TRACE model that helped to improve the code predictions, including the modeling of dynamical heat losses, the nodalization of SGs' heat exchanger tubes and the ACCs. Another relevant aspect of this work is to evaluate how well the model simulations of the three different scenarios qualitatively and quantitatively capture the trends and results exhibited by the actual experiments. For instance, how the number of SGs considered for

Lightning rod ionizing natural ionca - Ionic electrode active trimetallictriac of grounding - Definitive and total solution against 'blackouts' and electrical faults generated by atmospheric charges (lightning)

Energy Technology Data Exchange (ETDEWEB)

Cabareda, Luis

2010-09-15

The Natural Ionizing System of Electrical Protection conformed by: Lightning Rod Ionizing Natural Ionca and Ionic Electrode Active Trimetallic Triac of Grounding offers Total Protection, Maximum Security and Zero Risk to Clinics, Hospitals, Integral Diagnostic Center, avoiding ''the burning'' of Electronics Cards; Refineries, Tanks and Stations of Fuel Provision; Electrical Substations, Towers and Transmission Lines with transformer protection, motors, elevators, A/C, mechanicals stairs, portable and cooling equipment, electrical plants, others. This New High Technology is the solution to the paradigm of Benjamin Franklin and it's the mechanism to end the 'Blackouts' that produces so many damages and losses throughout the world.

Development of the stationary state and simulation of an accident severe stage type station blackout with the MELCOR code version 1.8.6 for the nuclear power plant of Laguna Verde

International Nuclear Information System (INIS)

Mugica R, C. A.; Godinez S, V.

2011-11-01

Considering the events happened since the 11 March of 2011, in Japan, where an earthquake of 9.1 grades Ritcher of intensity and a later tsunami impacted in an important way the operation of a nuclear power plant located in the Fukushima, Japan; damaging and disabling their cooling systems and injection of emergency water due to the total loss of electric power (commonly denominated Station Blackout), is eminent the analysis of this stage type that took to the nuclear power plant to conditions of damage to the core and explosions generation by hydrogen concentrations in the reactor building. In this work an analysis of a stage type station blackout is presented, using the model of the nuclear power plant of Laguna Verde starting of the stationary state. The analysis is carried out using the MELCOR code (Methods for Estimation of Leakages and Consequences of Releases) version 1.8.6 whose purpose is to model the accidents progression for light water reactors. The obtained results are qualitatively similar to the events observed in the Fukushima nuclear power plant even though limitations exist to achieve a precise simulation of the events happened in Japan, such as the information flow of the chronology of the operator actions, as well as of the characteristic design of the power plant, volumes in cavities and rooms, water/cooling inventories, interconnected systems and their own emergency procedures or guides for the administration of severe accidents among others. (Author)

Development of the APR1400 model for countercurrent natural circulation in hot leg and steam generator under station blackout

International Nuclear Information System (INIS)

Park, Sang Gil; Kim, Han Chul

2012-01-01

In order to analyze severe accident phenomena, Korea Institute of Nuclear Safety (KINS) made a MELCOR model for APR1400 to examine natural circulation and creep rupture failure in the Reactor Coolant System (RCS) under station blackout (SBO). In this study, we are trying to advance the former model to describe natural circulation more accurately. After Fukushima accident, the concerns of severe accident management, assuring the heat removal capability, has risen for the case when the SBO is happened and there are no more electric powers to cool down decay heat. Under SBO there are three kinds of natural circulation which can delay the core heatup. One is in vessel natural circulation in the upper plenum of reactor vessel and the second is countercurrent natural circulation in hot leg through steam generator tubes and the last is full loop natural circulation when the reactor coolant pump loop seal is cleared and reactor coolant pump sealing is damaged by high temperature and high pressure. Among them this study focuses on the countercurrent natural circulation model using MELCOR1.8.6

Analyses of natural circulation during a Surry station blackout using SCDAP/RELAP5

International Nuclear Information System (INIS)

Bayless, P.D.

1988-10-01

The effects of reactor coolant system natural circulation on the response of the Surry nuclear power plant during a station blackout transient were investigated. A TMLB' sequence (loss of all ac power, immediate loss of auxillary feedwater) was simulated from transient initiation until after fuel rod relocation had begun. Integral analyses of the system thermal-hydraulics and the core damage behavior were performed using the SCDAP/RELAP5 computer code and several different models of the plant. Three scoping calculations were performed in which the complexity of the plant model was progressively increased to determine the overall effects of in-vessel and hot leg natural circulation flows on the plant response. The natural circulation flows extended the transient, slowing the core heatup and delaying core damage by transferring energy from the core to structures in the upper plenum and coolant loops. Increased temperatures in the ex-core structures indicated that they may fail, however. Nine sensitivity calculations were then performed to investigate the effects of modeling uncertainties on the multidimensional natural circulation flows and the system response. Creep rupture failure of the pressurizer surge line was predicted to occur in eight of the calculations, with the hot leg failing in the ninth. The failure time was fairly insensitive to the parameters varied. The failures occurred near the time that fuel rod relocation began, well before failure of the reactor vessel would be expected. A calculation was also performed in which creep rupture failure of the surge line was modeled. The subsequent blowdown led to rapid accumulator injection and quenching of the entire core. 18 refs., 105 figs., 17 tabs

Comparative study of the hydrogen generation during short term station blackout (STSBO) in a BWR

International Nuclear Information System (INIS)

Polo-Labarrios, M.A.; Espinosa-Paredes, G.

2015-01-01

Highlights: • Comparative study of generation in a simulated STSBO severe accident. • MELCOR and SCDAP/RELAP5 codes were used to understanding the main phenomena. • Both codes present similar thermal-hydraulic behavior for pressure and boil off. • SCDAP/RELAP5 predicts 15.8% lower hydrogen production than MELCOR. - Abstract: The aim of this work is the comparative study of hydrogen generation and the associated parameters in a simulated severe accident of a short-term station blackout (STSBO) in a typical BWR-5 with Mark-II containment. MELCOR (v.1.8.6) and SCDAP/RELAP5 (Mod.3.4) codes were used to understand the main phenomena in the STSBO event through the results comparison obtained from simulations with these codes. Due that the simulation scope of SCDAP/RELAP5 is limited to failure of the vessel pressure boundary, the comparison was focused on in-vessel severe accident phenomena; with a special interest in the vessel pressure, boil of cooling, core temperature, and hydrogen generation. The results show that at the beginning of the scenario, both codes present similar thermal-hydraulic behavior for pressure and boil off of cooling, but during the relocation, the pressure and boil off, present differences in timing and order of magnitude. Both codes predict in similar time the beginning of melting material drop to the lower head. As far as the hydrogen production rate, SCDAP/RELAP5 predicts 15.8% lower production than MELCOR

RELAP5/MOD3.3 Analyses of Core Heatup Prevention Strategy During Extended Station Blackout in PWR

International Nuclear Information System (INIS)

Prosek, A.

2016-01-01

The accident at the Fukushima Dai-ichi nuclear power plant demonstrated the vulnerability of the plants on the loss of electrical power for several days, so called extended station blackout (SBO). A set of measures have been proposed and implemented in response of the accident at the Fukushima Dai-ichi nuclear power plant. The purpose of the study was to investigate the application of the deterministic safety analysis for core heatup prevention strategy of the extended SBO in pressurized water reactor, lasting 72 h. The prevention strategy selected was water injection into steam generators using turbine driven auxiliary feedwater pump (TD-AFW) or portable water injection pump. Method for assessment of the necessary pump injection flowrate is developed and presented. The necessary injection flowrate to the steam generators is determined from the calculated cumulative water mass injected by the turbine driven auxiliary feedwater pump in the analysed scenarios, when desired normal level is maintained automatically. The developed method allows assessment of the necessary injection flowrates of pump, TD-AFW or portable, for different plant configurations and number of flowrate changes. The RELAP5/MOD3.3 Patch04 computer code and input model of a two-loop pressurized water reactor is used for analyses, assuming different injection start times, flowrates and reactor coolant system losses. Three different reactor coolant system (RCS) coolant loss pathways, with corresponding leakage rate, can be expected in the pressurized water reactor (PWR) during the extended SBO: normal system leakage, reactor coolant pump seal leakage, and RCS coolant loss through letdown relief valve unless automatically isolated or until isolation is procedurally directed. Depressurization of RCS was also considered. In total, six types of RCS coolant loss scenarios were considered. Two cases were defined regarding the operation of the emergency diesel generators. Different delays of the pump

Analysis of fuel handling system for fuel bundle safety during station blackout in 500 MWe PHWR unit of India

International Nuclear Information System (INIS)

Madhuresh, R.; Nagarajan, R.; Jit, I.; Sanatkumar, A.

1996-01-01

Situations of Station Blackout (SBO) i.e. postulated concurrent unavailability of Class Ill and Class IV power, could arise for a long period, while on-power refuelling or other fuel handling operations are in progress with the hot irradiated fuel bundles being anywhere in the system from the Reactor Building to the Spent Fuel Storage Bay. The cooling provisions for these fuel bundles are diverse and specific to the various stages of fuel handling operations and are either on Class Ill or on Class II power with particular requirements of instrument air. Therefore, during SBO, due to the limited availability of Class II power and instrument air, it becomes difficult to maintain cooling to these fuel bundles. However, some minimal cooling is essential, to ensure the safety of the bundles. As discussed in the paper, safety of these fuel bundles in the system and/or for those lying in the liner tube region of the reactor end fitting is ensured, during SBO, by resorting to passive means like 'stay-put', 'gravity- fill', 'D 2 0- steaming' etc. for cooling the bundles. The paper also describes various consequences emanating from these cooling schemes. (author). 6 refs., 2 tabs., 8 figs

Electrical Power System Design and Station Blackout (SBO) Management in Indian Fast Breeder Reactors

International Nuclear Information System (INIS)

Vijaya, N. M.; Theivarajan, N.; Madhusoodanan, K.

2015-01-01

In the nuclear new builds and projects in design stage SBO management measures have significant role. Depending on the onsite and offsite power supply configurations, deterministic SBO duration is established. Design of systems with adequately sized battery capacities for SBO duration, special SBO Diesel Generator Sets, structured load shedding strategy to conserve battery availability to cope with SBO and to monitor the plant safety beyond SBO duration are considered as part of electrical system design now. In the design of PFBR, SBO is given due importance right from conceptual design stage. Both deterministic SBO duration and probabilistic SBO duration versus frequency were established by detailed analysis. Dedicated DC power supply systems and additional SBO DG back-up systems are in place to cope with normal and extended SBO. After the Fukushima event, there is greater requirement to demonstrate plant safety during SBO for a long duration extended over several days. In light of this accident, thermal hydraulic synthesis of PFBR has been carried out to ascertain the capability of the plant to manage a prolonged station blackout event. This has brought out the robustness of the design. Safety design features of PFBR ensure comfortable management of extended SBO. In the design of future FBR projects, current trends in the new nuclear builds and recommendations of international bodies considering Fukushima are duly considered. SBO measures by means of alternate AC power sources, redundant emergency power supply sources with less dependence on other auxiliary systems and dedicated DC power systems are considered to cope with normal and extended SBO beyond design basis. Right from the conceptual design, the system robustness to manage normal and extended SBO will be taken care with the related thermal hydraulic and associated analysis. The paper highlights these SBO management strategies in PFBR and future FBRs. (author)

Investigation of SAM measures during selected MBLOCA sequences along with Station Blackout in a generic Konvoi PWR using ASTECV2.0

International Nuclear Information System (INIS)

Gómez-García-Toraño, Ignacio; Sánchez Espinoza, Víctor Hugo; Stieglitz, Robert

2017-01-01

Highlights: • Reflooding is investigated for selected MBLOCA sequences in a Konvoi PWR using ASTEC. • After SBO, there is a grace time of 40 min up to the detection of a CET = 650 °C. • Major core damage prevented if reflood is launched at CET = 650 °C with 25-40 kg/s. • Values depend on the time when the plant is struck by Station Blackout. • Vessel failure cannot be prevented if supplied mass flow rates are lower than 10 kg/s. - Abstract: The Fukushima accidents have shown that further improvement of Severe Accident Management Guidelines (SAMGs) is necessary for the current fleet of Light Water Reactors. The elaboration of SAMGs requires a broad database of deterministic analyses performed with state-of-the art simulation tools. Within this work, the ASTECV2.0 integral severe accident code is used to study the efficiency of core reflooding (as a SAM measure) during postulated Medium Break LOCA (MBLOCA) scenarios in a German Konvoi PWR. In a first step, the progression of selected MBLOCA sequences without SAM measures has been analysed. The sequences postulate a break in the cold leg of the pressurizer loop and the total loss of AC power at a given stage of the accident. Results show the existence of a 40 min grace time up to the detection of a Core Exit Temperature (CET) of 650 °C providing that the AC power has been maintained at least 1 h after SCRAM. In a second step, an extensive analysis on core reflooding has been carried out. The sequences assume that the plant remains in Station Blackout (SBO) and that reflooding occurs at different times with different mobile pumps. The simulations yield the following results: • Reflooding mass flow rates above 60 kg/s have to be supplied as soon as the CET exceeds 650 °C in order to prevent core melting. • Reflooding mass flow rates ranging from 25–40 kg/s at CET = 650 °C mitigate the accident without major core damage depending on when the plant enters in SBO. • Reflooding mass flow rates lower

Alcohol-related blackouts among college students: impact of low level of response to alcohol, ethnicity, sex, and environmental characteristics

Directory of Open Access Journals (Sweden)

Priscila D. Gonçalves

2017-08-01

Full Text Available Objective: To explore how a genetically-influenced characteristic (the level of response to alcohol [LR], ethnicity, and sex relate to environmental and attitudinal characteristics (peer drinking [PEER], drinking to cope [COPE], and alcohol expectancies [EXPECT] regarding future alcohol-related blackouts (ARBs. Methods: Structural equation models (SEMs were used to evaluate how baseline variables related to ARB patterns in 462 college students over 55 weeks. Data were extracted from a longitudinal study of heavy drinking and its consequences at a U.S. university. Results: In the SEM analysis, female sex and Asian ethnicity directly predicted future ARBs (beta weights 0.10 and -0.11, respectively, while all other variables had indirect impacts on ARBs through alcohol quantities (beta weights ~ 0.23 for European American ethnicity and low LR, 0.21 for cannabis use and COPE, and 0.44 for PEER. Alcohol quantities then related to ARBs with beta = 0.44. The SEM explained 23% of the variance. Conclusion: These data may be useful in identifying college students who are more likely to experience future ARBs over a 1-year period. They enhance our understanding of whether the relationships of predictors to ARBs are direct or mediated through baseline drinking patterns, information that may be useful in prevention strategies for ARBs.

Analysis of fuel handling system for fuel bundle safety during station blackout in 500 MWe PHWR unit of India

Energy Technology Data Exchange (ETDEWEB)

Madhuresh, R; Nagarajan, R; Jit, I; Sanatkumar, A [Nuclear Power Corporation of India Ltd., Mumbai (India)

1997-12-31

Situations of Station Blackout (SBO) i.e. postulated concurrent unavailability of Class Ill and Class IV power, could arise for a long period, while on-power refuelling or other fuel handling operations are in progress with the hot irradiated fuel bundles being anywhere in the system from the Reactor Building to the Spent Fuel Storage Bay. The cooling provisions for these fuel bundles are diverse and specific to the various stages of fuel handling operations and are either on Class Ill or on Class II power with particular requirements of instrument air. Therefore, during SBO, due to the limited availability of Class II power and instrument air, it becomes difficult to maintain cooling to these fuel bundles. However, some minimal cooling is essential, to ensure the safety of the bundles. As discussed in the paper, safety of these fuel bundles in the system and/or for those lying in the liner tube region of the reactor end fitting is ensured, during SBO, by resorting to passive means like `stay-put`, `gravity- fill`, `D{sub 2}0- steaming` etc. for cooling the bundles. The paper also describes various consequences emanating from these cooling schemes. (author). 6 refs., 2 tabs., 8 figs.

Summary of ROSA-4 LSTF first phase test program and station blackout (TMLB) test results

International Nuclear Information System (INIS)

Tasaka, K.; Kukita, Y.; Anoda, Y.

1990-01-01

This paper summarizes major test results obtained at the ROSA-4 Large Scale Test Facility (LSTF) during the first phase of the test program. The results from a station blackout (TMLB) test conducted at the end of the first-phase program are described in some detail. The LSTF is an integral test facility being operated by the Japan Atomic Energy Research Institute for simulation of pressurized water reactor (PWR) thermal-hydraulic responses during small-break loss-of-coolant accidents (SBLOCAs) and operational/abnormal transients. It is a 1/48 volumetrically scaled, full-height, full-pressure simulator of a Westinghouse-type 4-loop PWR. The facility includes two symmetric primary loops each one containing an active inverted-U tube steam generator and an active reactor coolant pump. The loop horizontal legs are sized to conserve the scaled (1/24) volumes as well as the length to the square root of the diameter ratio in order to simulate the two-phase flow regime transitions. The primary objective of the LSTF first-phase program was to define the fundamental PWR thermal-hydraulic responses during SBLOCAs and transients. Most of the tests were conducted with simulated component/operator failures, including unavailability of the high pressure injection system and auxiliary feedwater system, as well as operator failure to take corrective actions. The forty-two first phase tests included twenty-nine SBLOCA tests conducted mainly for cold leg breaks, three abnormal transient tests and ten natural circulation tests. Attempts were made in several of the SBLOCA tests to simulate the plant recovery procedures as well as candidate accident management measures for prevention of high-pressure core melt situation. The natural circulation tests simulated the single-phase and two-phase natural circulation as well as reflux condensation behavior in the primary loops in steady or quasi-steady states

Evaluation of steam generator U-tube integrity during PWR station blackout with secondary system depressurization

International Nuclear Information System (INIS)

Hidaka, Akihide; Asaka, Hideaki; Sugimoto, Jun; Ueno, Shingo; Yoshino, Takehito

1999-12-01

In PWR severe accidents such as station blackout, the integrity of steam generator U-tube would be threatened early at the transient among the pipes of primary system. This is due to the hot leg countercurrent natural circulation (CCNC) flow which delivers the decay heat of the core to the structures of primary system if the core temperature increases after the secondary system depressurization. From a view point of accident mitigation, this steam generator tube rupture (SGTR) is not preferable because it results in the direct release of primary coolant including fission products (FP) to the environment. Recent SCDAP/RELAP5 analyses by USNRC showed that the creep failure of pressurizer surge line which results in release of the coolant into containment would occur earlier than SGTR during the secondary system depressurization. However, the analyses did not consider the decay heat from deposited FP on the steam generator U-tube surface. In order to investigate the effect of decay heat on the steam generator U-tube integrity, the hot leg CCNC flow model used in the USNRC's calculation was, at first, validated through the analysis for JAERI's LSTF experiment. The CCNC model reproduced well the thermohydraulics observed in the LSTF experiment and thus the model is mostly reliable. An analytical study was then performed with SCDAP/RELAP5 for TMLB' sequence of Surry plant with and without secondary system depressurization. The decay heat from deposited FP was calculated by JAERI's FP aerosol behavior analysis code, ART. The ART analysis showed that relatively large amount of FPs may deposit on steam generator U-tube inlet mainly by thermophoresis. The SCDAP/RELAP5 analyses considering the FP decay heat predicted small safety margin for steam generator U-tube integrity during secondary system depressurization. Considering associated uncertainties in the analyses, the potential for SGTR cannot be ignored. Accordingly, this should be considered in the evaluation of merits

AP1000 station blackout study with and without depressurization using RELAP5/SCDAPSIM

Energy Technology Data Exchange (ETDEWEB)

Trivedi, A.K. [Nuclear Engineering and Technology Program, Indian Institute of Technology, Kanpur 208016 (India); Allison, C. [Innovative Systems Software Idaho Falls, ID 83406 (United States); Khanna, A., E-mail: akhanna@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology, Kanpur 208016 (India); Munshi, P. [Nuclear Engineering and Technology Program, Indian Institute of Technology, Kanpur 208016 (India)

2016-10-15

Highlights: • A representative RELAP5/SCDAPSIM model of AP1000 has been developed. • Core is modeled using SCDAP. • A SBO for the AP1000 has been simulated for high pressure (no depressurization) and low pressure (depressurization). • Significant differences in the damage progression have been observed for the two cases. • Results also reinforced the fact that surge line fails before vessel failure in case of high pressure scenario. - Abstract: Severe accidents like TMI-2, Chernobyl, Fukushima made it inevitable to analyze station blackout (SBO) for all the old as well as new designs although it is not a regulatory requirement in most of the countries. For such improbable accidents, a SBO for the AP1000 using RELAP5/SCDAPSIM has been simulated. Many improvements have been made in fuel damage progression models of SCDAP after the Fukushima accident which are now being tested for the new reactor designs. AP1000 is a 2-loop pressurized water reactor (PWR) with all the emergency core cooling systems based on natural circulation. Its core design is very similar to 3-loop PWR with 157 fuel assemblies. The primary circuit pumps, pressurizer and steam generators (with necessary secondary side) are modeled using RELAP5. The core has been divided into 20 axial nodes and 6 radial rings; the corresponding six groups of assemblies have been modeled as six pipe components with proportionate flow area. Fuel assemblies are modeled using SCDAP fuel and control components. SCDAP has 2d-heat conduction and radiative heat transfer, oxidation and complete severe fuel damage progression models. The final input deck achieved all the steady state thermal hydraulic conditions comparable to the design control document of AP1000. To quantify the core behavior, under unavailability of all safety systems, various time profiles for SBO simulations @ high pressure and low pressure have been compared. This analysis has been performed for 102% (3468 MWt) of the rated core power. The

Development of Early Warning Methods for Electric Power Systems

DEFF Research Database (Denmark)

Jóhannsson, Hjörtur

This thesis concerns the development of methods that can provide, in realtime, an early warning for an emerging blackout in electric power systems. The blackout in E-Denmark and S-Sweden on September 23, 2003 is the main motivation for the method development. The blackout was caused by occurrence...

Emergency diesel generator reliability program

International Nuclear Information System (INIS)

Serkiz, A.W.

1989-01-01

The need for an emergency diesel generator (EDG) reliability program has been established by 10 CFR Part 50, Section 50.63, Loss of All Alternating Current Power, which requires that utilities assess their station blackout duration and recovery capability. EDGs are the principal emergency ac power sources for coping with a station blackout. Regulatory Guide 1.155, Station Blackout, identifies a need for (1) an EDG reliability equal to or greater than 0.95, and (2) an EDG reliability program to monitor and maintain the required levels. The resolution of Generic Safety Issue (GSI) B-56 embodies the identification of a suitable EDG reliability program structure, revision of pertinent regulatory guides and Tech Specs, and development of an Inspection Module. Resolution of B-56 is coupled to the resolution of Unresolved Safety Issue (USI) A-44, Station Blackout, which resulted in the station blackout rule, 10 CFR 50.63 and Regulatory Guide 1.155, Station Blackout. This paper discusses the principal elements of an EDG reliability program developed for resolving GSI B-56 and related matters

A STRONGLY COUPLED REACTOR CORE ISOLATION COOLING SYSTEM MODEL FOR EXTENDED STATION BLACK-OUT ANALYSES

Energy Technology Data Exchange (ETDEWEB)

Zhao, Haihua [Idaho National Laboratory; Zhang, Hongbin [Idaho National Laboratory; Zou, Ling [Idaho National Laboratory; Martineau, Richard Charles [Idaho National Laboratory

2015-03-01

The reactor core isolation cooling (RCIC) system in a boiling water reactor (BWR) provides makeup cooling water to the reactor pressure vessel (RPV) when the main steam lines are isolated and the normal supply of water to the reactor vessel is lost. The RCIC system operates independently of AC power, service air, or external cooling water systems. The only required external energy source is from the battery to maintain the logic circuits to control the opening and/or closure of valves in the RCIC systems in order to control the RPV water level by shutting down the RCIC pump to avoid overfilling the RPV and flooding the steam line to the RCIC turbine. It is generally considered in almost all the existing station black-out accidents (SBO) analyses that loss of the DC power would result in overfilling the steam line and allowing liquid water to flow into the RCIC turbine, where it is assumed that the turbine would then be disabled. This behavior, however, was not observed in the Fukushima Daiichi accidents, where the Unit 2 RCIC functioned without DC power for nearly three days. Therefore, more detailed mechanistic models for RCIC system components are needed to understand the extended SBO for BWRs. As part of the effort to develop the next generation reactor system safety analysis code RELAP-7, we have developed a strongly coupled RCIC system model, which consists of a turbine model, a pump model, a check valve model, a wet well model, and their coupling models. Unlike the traditional SBO simulations where mass flow rates are typically given in the input file through time dependent functions, the real mass flow rates through the turbine and the pump loops in our model are dynamically calculated according to conservation laws and turbine/pump operation curves. A simplified SBO demonstration RELAP-7 model with this RCIC model has been successfully developed. The demonstration model includes the major components for the primary system of a BWR, as well as the safety

An uncertainty analysis of the hydrogen source term for a station blackout accident in Sequoyah using MELCOR 1.8.5

Energy Technology Data Exchange (ETDEWEB)

Gauntt, Randall O.; Bixler, Nathan E.; Wagner, Kenneth Charles.

2014-03-01

A methodology for using the MELCOR code with the Latin Hypercube Sampling method was developed to estimate uncertainty in various predicted quantities such as hydrogen generation or release of fission products under severe accident conditions. In this case, the emphasis was on estimating the range of hydrogen sources in station blackout conditions in the Sequoyah Ice Condenser plant, taking into account uncertainties in the modeled physics known to affect hydrogen generation. The method uses user-specified likelihood distributions for uncertain model parameters, which may include uncertainties of a stochastic nature, to produce a collection of code calculations, or realizations, characterizing the range of possible outcomes. Forty MELCOR code realizations of Sequoyah were conducted that included 10 uncertain parameters, producing a range of in-vessel hydrogen quantities. The range of total hydrogen produced was approximately 583kg 131kg. Sensitivity analyses revealed expected trends with respected to the parameters of greatest importance, however, considerable scatter in results when plotted against any of the uncertain parameters was observed, with no parameter manifesting dominant effects on hydrogen generation. It is concluded that, with respect to the physics parameters investigated, in order to further reduce predicted hydrogen uncertainty, it would be necessary to reduce all physics parameter uncertainties similarly, bearing in mind that some parameters are inherently uncertain within a range. It is suspected that some residual uncertainty associated with modeling complex, coupled and synergistic phenomena, is an inherent aspect of complex systems and cannot be reduced to point value estimates. The probabilistic analyses such as the one demonstrated in this work are important to properly characterize response of complex systems such as severe accident progression in nuclear power plants.

The safety assessment of OPR-1000 nuclear power plant for station blackout accident applying the combined deterministic and probabilistic procedure

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong Gu, E-mail: littlewing@kins.re.kr [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 305-338 (Korea, Republic of); Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Chang, Soon Heung [Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2014-08-15

Highlights: • The combined deterministic and probabilistic procedure (CDPP) was proposed for safety assessment of the BDBAs. • The safety assessment of OPR-1000 nuclear power plant for SBO accident is performed by applying the CDPP. • By estimating the offsite power restoration time appropriately, the SBO risk is reevaluated. • It is concluded that the CDPP is applicable to safety assessment of BDBAs without significant erosion of the safety margin. - Abstract: Station blackout (SBO) is a typical beyond design basis accident (BDBA) and significant contributor to overall plant risk. The risk analysis of SBO could be important basis of rulemaking, accident mitigation strategy, etc. Recently, studies on the integrated approach of deterministic and probabilistic method for nuclear safety in nuclear power plants have been done, and among them, the combined deterministic and probabilistic procedure (CDPP) was proposed for safety assessment of the BDBAs. In the CDPP, the conditional exceedance probability obtained by the best estimate plus uncertainty method acts as go-between deterministic and probabilistic safety assessments, resulting in more reliable values of core damage frequency and conditional core damage probability. In this study, the safety assessment of OPR-1000 nuclear power plant for SBO accident was performed by applying the CDPP. It was confirmed that the SBO risk should be reevaluated by eliminating excessive conservatism in existing probabilistic safety assessment to meet the targeted core damage frequency and conditional core damage probability. By estimating the offsite power restoration time appropriately, the SBO risk was reevaluated, and it was finally confirmed that current OPR-1000 system lies in the acceptable risk against the SBO. In addition, it is concluded that the CDPP is applicable to safety assessment of BDBAs in nuclear power plants without significant erosion of the safety margin.

Alcohol-Related Blackouts, Negative Alcohol-Related Consequences, and Motivations for Drinking Reported by Newly Matriculating Transgender College Students.

Science.gov (United States)

Tupler, Larry A; Zapp, Daniel; DeJong, William; Ali, Maryam; O'Rourke, Sarah; Looney, John; Swartzwelder, H Scott

2017-05-01

Many transgender college students struggle with identity formation and other emotional, social, and developmental challenges associated with emerging adulthood. A potential maladaptive coping strategy employed by such students is heavy drinking. Prior literature has suggested greater consumption and negative alcohol-related consequences (ARCs) in transgender students compared with their cisgender peers, but little is known about their differing experiences with alcohol-related blackouts (ARBs). We examined the level of alcohol consumption, the frequency of ARBs and other ARCs, and motivations for drinking reported by the largest sample of transgender college students to date. A Web survey from an alcohol-prevention program, AlcoholEdu for College™, assessed student demographics and drinking-related behaviors, experiences, and motivations of newly matriculating first-year college students. A self-reported drinking calendar was used to examine each of the following measures over the previous 14 days: number of drinking days, total number of drinks, and maximum number of drinks on any single day. A 7-point Likert scale was used to measure ARCs, ARBs, and drinking motivations. Transgender students of both sexes were compared with their cisgender peers. A total of 989 of 422,906 students (0.2%) identified as transgender. Over a 14-day period, transgender compared with cisgender students were more likely to consume alcohol over more days, more total drinks, and a greater number of maximum drinks on a single day. Transgender students (36%) were more likely to report an ARB than cisgender students (25%) as well as more negative academic, confrontation-related, social, and sexual ARCs. Transgender respondents more often cited stress reduction, social anxiety, self-esteem issues, and the inherent properties of alcohol as motivations for drinking. For nearly all measures, higher values were yielded by male-to-female than female-to-male transgender students. Transgender

A FMM-FFT accelerated hybrid volume surface integral equation solver for electromagnetic analysis of re-entry space vehicles

KAUST Repository

Yü cel, Abdulkadir C.; Gomez, Luis J.; Liu, Yang; Bagci, Hakan; Michielssen, Eric

2014-01-01

Space vehicles that re-enter the atmosphere often experience communication blackout. The blackout occurs when the vehicle becomes engulfed in plasma produced by interactions between the vehicle surface and the atmosphere. The plasma often

ASCERTAINMENT OF ELECTRIC-SUPPLY SCHEMES RELIABILITY FOR THE ATOMIC POWER PLANT AUXILIARIES

Directory of Open Access Journals (Sweden)

A. L. Starzhinskij

2015-01-01

Full Text Available The paper completes ascertainment of electrical-supply scheme reliability for the auxiliaries of a nuclear power plant. Thereat the author considers the system behavior during the block normal operation, carrying out current maintenance, and capital repairs in combination with initiating events. The initiating events for reactors include complete blackout, i.e. the loss of outside power supply (normal and reserve; emergency switching one of the working turbogenerators; momentary dumping the normal rating to the level of auxiliaries with seating the cutout valve of one turbo-generator. The combination of any initiating event with the repairing mode in case of one of the system elements failure should not lead to blackout occurrence of more than one system of the reliable power supply. This requirement rests content with the help of the reliable power supply system self-dependence (electrical and functional and the emergency power-supply operational autonomy (diesel generator and accumulator batteries.The reliability indicators of the power supply system for the nuclear power plant auxiliaries are the conditional probabilities of conjoined blackout of one, two, and three sections of the reliable power supply conditional upon an initiating event emerging and the blackout of one, two, and three reliable power-supply sections under the normal operational mode. Furthermore, they also are the blackout periodicity of one and conjointly two, three, and four sections of normal operation under the block normal operational mode. It is established that the blackout of one bus section of normal operation and one section of reliable power-supply system of the auxiliaries that does not lead to complete blackout of the plant auxiliaries may occur once in three years. The probability of simultaneous power failure of two or three normal-operation sections and of two reliable power-supply sections during the power plant service life is unlikely.

Influence of magnetic window for mitigating on antenna performance in plasma

International Nuclear Information System (INIS)

Xing Xiaojun; Zhao Qing; Zheng Ling; Tang Jianming; Chen Yuxu; Liu Shuzhang

2013-01-01

The communication blackout caused by the plasma sheath around a hypersonic vehicle flying in atmosphere is a problem to aerospace vehicles. When a vehicle enters the communication blackout phase, it loses all communication including GPS signals, data telemetry, and voice communication. The communication blackout becomes an even more critical issue with development of re-entry vehicles missions. During such missions, the communication loss caused by radio blackout introduces significant problems related to the vehicle's safety. This paper analyzes the interaction of electromagnetic waves with plasma in an external magnetic field in theory. The external magnetic field can improve the transmission of electromagnetic waves in plasma from the theoretical analysis. The magnetic window antenna which is designed by integrating the permanent magnet and the helical antenna is proposed. The performance of the helical antenna and magnetic window antenna in plasma is studied. The simulation results show that using the magnetic window antenna can weaken the influence on the antenna performance in plasma. The magnetic window antenna makes it possible for electromagnetic waves to spread in plasma. This provides another way to solve the problem of spacecraft re-entry blackout. (authors)

Major power system failures (Europe, USA) and deregulation of electricity markets

International Nuclear Information System (INIS)

Merlin, A.

2004-01-01

The year 2003 was marked by several electric power blackouts which affected major power systems in the world, and gave rise to many opinions about possible links with developments brought by the opening of the electricity markets. At first the paper presents the outages experienced by North America or August 14 and by Switzerland and Italy on September 28, 2003. Feedback on previous electric power blackouts makes possible to find out already known lessons, then to bring out how the latest blackouts may reveal similarities or differences towards developments brought by the opening of the electricity markets occurred ire the last ten years. Finally, seen from the transmission system operator of a european country within the context of continued institutional developments, the paper points out significant items which must be considered to prevent possible further blackouts. (author)

Comparison of MELCOR modeling techniques and effects of vessel water injection on a low-pressure, short-term, station blackout at the Grand Gulf Nuclear Station

International Nuclear Information System (INIS)

Carbajo, J.J.

1995-06-01

A fully qualified, best-estimate MELCOR deck has been prepared for the Grand Gulf Nuclear Station and has been run using MELCOR 1.8.3 (1.8 PN) for a low-pressure, short-term, station blackout severe accident. The same severe accident sequence has been run with the same MELCOR version for the same plant using the deck prepared during the NUREG-1150 study. A third run was also completed with the best-estimate deck but without the Lower Plenum Debris Bed (BH) Package to model the lower plenum. The results from the three runs have been compared, and substantial differences have been found. The timing of important events is shorter, and the calculated source terms are in most cases larger for the NUREG-1150 deck results. However, some of the source terms calculated by the NUREG-1150 deck are not conservative when compared to the best-estimate deck results. These results identified some deficiencies in the NUREG-1150 model of the Grand Gulf Nuclear Station. Injection recovery sequences have also been simulated by injecting water into the vessel after core relocation started. This marks the first use of the new BH Package of MELCOR to investigate the effects of water addition to a lower plenum debris bed. The calculated results indicate that vessel failure can be prevented by injecting water at a sufficiently early stage. No pressure spikes in the vessel were predicted during the water injection. The MELCOR code has proven to be a useful tool for severe accident management strategies

Branch-and-Bound algorithm applied to uncertainty quantification of a Boiling Water Reactor Station Blackout

International Nuclear Information System (INIS)

Nielsen, Joseph; Tokuhiro, Akira; Hiromoto, Robert; Tu, Lei

2015-01-01

state. Dynamic PRA (DPRA) methods provide a more rigorous analysis of complex dynamic systems. Unfortunately DPRA methods introduce issues associated with combinatorial explosion of states. This paper presents a methodology to address combinatorial explosion using a Branch-and-Bound algorithm applied to Dynamic Event Trees (DET), which utilize LENDIT (L – Length, E – Energy, N – Number, D – Distribution, I – Information, and T – Time) as well as a set theory to describe system, state, resource, and response (S2R2) sets to create bounding functions for the DET. The optimization of the DET in identifying high probability failure branches is extended to create a Phenomenological Identification and Ranking Table (PIRT) methodology to evaluate modeling parameters important to safety of those failure branches that have a high probability of failure. The PIRT can then be used as a tool to identify and evaluate the need for experimental validation of models that have the potential to reduce risk. In order to demonstrate this methodology, a Boiling Water Reactor (BWR) Station Blackout (SBO) case study is presented.

Branch-and-Bound algorithm applied to uncertainty quantification of a Boiling Water Reactor Station Blackout

Energy Technology Data Exchange (ETDEWEB)

Nielsen, Joseph, E-mail: joseph.nielsen@inl.gov [Idaho National Laboratory, 1955 N. Fremont Avenue, P.O. Box 1625, Idaho Falls, ID 83402 (United States); University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Tokuhiro, Akira [University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Hiromoto, Robert [University of Idaho, Department of Computer Science, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States); Tu, Lei [University of Idaho, Department of Mechanical Engineering and Nuclear Engineering Program, 1776 Science Center Drive, Idaho Falls, ID 83402-1575 (United States)

2015-12-15

state. Dynamic PRA (DPRA) methods provide a more rigorous analysis of complex dynamic systems. Unfortunately DPRA methods introduce issues associated with combinatorial explosion of states. This paper presents a methodology to address combinatorial explosion using a Branch-and-Bound algorithm applied to Dynamic Event Trees (DET), which utilize LENDIT (L – Length, E – Energy, N – Number, D – Distribution, I – Information, and T – Time) as well as a set theory to describe system, state, resource, and response (S2R2) sets to create bounding functions for the DET. The optimization of the DET in identifying high probability failure branches is extended to create a Phenomenological Identification and Ranking Table (PIRT) methodology to evaluate modeling parameters important to safety of those failure branches that have a high probability of failure. The PIRT can then be used as a tool to identify and evaluate the need for experimental validation of models that have the potential to reduce risk. In order to demonstrate this methodology, a Boiling Water Reactor (BWR) Station Blackout (SBO) case study is presented.

Mars Atmospheric Entry Integrated Navigation with Partial Intermittent Measurements

Directory of Open Access Journals (Sweden)

Tai-shan Lou

2017-01-01

Full Text Available Signal degradation suffered by the vehicle is a combination brownout and blackout during Mars atmospheric entry. The communications brownout means that signal fades and blackout means that the signal is lost completely. The communications brownout and blackout periods are analyzed and predicted with an altitude and velocity profiles. In the brownout period, the range measurements between the vehicle and the orbiters are modeled as intermittent measurements with the radio signal arrival probabilities, which are distributed as a Rayleigh distribution of the electron number density around the entry vehicle. A new integrated navigation strategy during the Mars atmospheric entry phase is proposed to consider the probabilities of the radio measurements in the communications brownout and blackout periods under the IMU/beacon scenario based on the information filter with intermittent measurements. Numerical navigation simulations are designed to show the performance of the proposed navigation strategy under the integrated navigation scenario.

A Case Report of Dissociative Neurosis (Depersonalization Disorder) in an Adolescent Treated with Family Therapy and Behavior Modification.

Science.gov (United States)

Dollinger, Stephen J.

1983-01-01

Describes the use of behavioral procedures as part of systems-oriented family therapy for the treatment of an adolescent girl's functional blackouts. Treatment successfully eliminated blackouts without directly addressing clear psychosexual issues. Discusses the case in terms of conceptualizing etiology and treatments and advocates working with…

Dispersed trading and the prevention of market failure

DEFF Research Database (Denmark)

Porter, David C.; Tanggaard, Carsten; Weaver, Daniel G.

2008-01-01

With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight...... into this issue by examining trading behaviour at the Copenhagen Stock Exchange during a major blackout. We find that although market quality declined, markets remained functional and some price discovery occurred during the blackout period suggesting that the NOREX structure of interlinked trading systems...... combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks....

Thermal-hydraulic analysis of NSSS and containment response during extended station blackout for Maanshan PWR plant

Energy Technology Data Exchange (ETDEWEB)

Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw; Hsu, Keng-Hsien, E-mail: hardlycampus@iner.gov.tw; Lin, Chin-Tsu, E-mail: jtling@iner.gov.tw

2015-07-15

Highlights: • Calculate NSSS and containment transient response during extended SBO of 24 h. • RELAP5-3D and GOTHIC models are developed for Maanshan PWR plant. • Reactor coolant pump seal leakage is specifically modeled for each loop. • Analyses are performed with and without secondary-side depressurization, respectively. • Considering different total available time for turbine driven auxiliary feedwater system. - Abstract: A thermal-hydraulic analysis has been performed with respect to the response of the nuclear steam supply system (NSSS) and the containment during an extended station blackout (SBO) duration of 24 h in Maanshan PWR plant. Maanshan plant is a Westinghouse three-loop PWR design with rated core thermal power of 2822 MWt. The analyses in the NSSS and the containment are based on the RELAP5-3D and GOTHIC models, respectively. Important design features of the plant in response to SBO are considered in the respective models, e.g., the steam generator PORVs, turbine driven auxiliary feedwater system (TDAFWS), accumulators, reactor coolant pump (RCP) seal design, various heat structures in the containment, etc. In the analysis it is assumed that the shaft seal in each RCP failed due to loss of seal cooling and the RCS fluid flows to the containment directly. Some parameters calculated from the RELPA5-3D model are input to the containment GOTHIC model, including the RCS average temperature and the RCP seal leakage flow and enthalpy. The RCS average temperature is used to drive the sensible heat transfer to the containment. It is found that the severity of the event depends mainly on whether the secondary side is depressurized or not. If the secondary side is depressurized in time (within 1 h after SBO) and the TDAFWS is available greater than 19 h, then the reactor core will be covered with water throughout the SBO duration, which ensures the integrity of the reactor core. On the contrary, if the secondary side is not depressurized, then the RCS

THE APPLICATION OF MAMMOTH FOR A DETAILED TIGHTLY COUPLED FUEL PIN SIMULATION WITH A STATION BLACKOUT

Energy Technology Data Exchange (ETDEWEB)

Gleicher, Frederick; Ortensi, Javier; DeHart, Mark; Wang, Yaqi; Schunert, Sebastian; Novascone, Stephen; Hales, Jason; Williamson, Rich; Slaughter, Andrew; Permann, Cody; Andrs, David; Martineau, Richard

2016-09-01

Accurate calculation of desired quantities to predict fuel behavior requires the solution of interlinked equations representing different physics. Traditional fuels performance codes often rely on internal empirical models for the pin power density and a simplified boundary condition on the cladding edge. These simplifications are performed because of the difficulty of coupling applications or codes on differing domains and mapping the required data. To demonstrate an approach closer to first principles, the neutronics application Rattlesnake and the thermal hydraulics application RELAP-7 were coupled to the fuels performance application BISON under the master application MAMMOTH. A single fuel pin was modeled based on the dimensions of a Westinghouse 17x17 fuel rod. The simulation consisted of a depletion period of 1343 days, roughly equal to three full operating cycles, followed by a station blackout (SBO) event. The fuel rod was depleted for 1343 days for a near constant total power loading of 65.81 kW. After 1343 days the fission power was reduced to zero (simulating a reactor shut-down). Decay heat calculations provided the time-varying energy source after this time. For this problem, Rattlesnake, BISON, and RELAP-7 are coupled under MAMMOTH in a split operator approach. Each system solves its physics on a separate mesh and, for RELAP-7 and BISON, on only a subset of the full problem domain. Rattlesnake solves the neutronics over the whole domain that includes the fuel, cladding, gaps, water, and top and bottom rod holders. Here BISON is applied to the fuel and cladding with a 2D axi-symmetric domain, and RELAP-7 is applied to the flow of the circular outer water channel with a set of 1D flow equations. The mesh on the Rattlesnake side can either be 3D (for low order transport) or 2D (for diffusion). BISON has a matching ring structure mesh for the fuel so both the power density and local burn up are copied accurately from Rattlesnake. At each depletion time

A Study of the Impact of Peak Demand on Increasing Vulnerability of Cascading Failures to Extreme Contingency Events

Energy Technology Data Exchange (ETDEWEB)

Vyakaranam, Bharat GNVSR; Vallem, Mallikarjuna R.; Nguyen, Tony B.; Samaan, Nader A.; Berscheid, Alan P.; Makarov, Yuri V.; Diao, Ruisheng

2017-10-02

The vulnerability of large power systems to cascading failures and major blackouts has become evident since the Northeast blackout in 1965. Based on analyses of the series of cascading blackouts in the past decade, the research community realized the urgent need to develop better methods, tools, and practices for performing cascading-outage analysis and for evaluating mitigations that are easily accessible by utility planning engineers. PNNL has developed the Dynamic Contingency Analysis Tool (DCAT) as an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. DCAT analysis will help identify potential vulnerabilities and allow study of mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. Using the DCAT capability, we examined the impacts of various load conditions to identify situations in which the power grid may encounter cascading outages that could lead to potential blackouts. This paper describes the usefulness of the DCAT tool and how it helps to understand potential impacts of load demand on cascading failures on the power system.

An empirical model of global spread-f occurrence

International Nuclear Information System (INIS)

Singleton, D.G.

1974-09-01

A method of combining models of ionospheric F-layer peak electron density and irregularity incremental electron density into a model of the occurrence probability of the frequency spreading component of spread-F is presented. The predictions of the model are compared with spread-F occurrence data obtained under sunspot maximum conditions. Good agreement is obtained for latitudes less than 70 0 geomagnetic. At higher latitudes, the inclusion of a 'blackout factor' in the model allows it to accurately represent the data and, in so doing, resolves an apparent discrepancy in the occurrence statistics at high latitudes. The blackout factor is ascribed to the effect of polar blackout on the spread-F statistics and/or the lack of a definitve incremental electron density model for irregularities at polar latitudes. Ways of isolating these effects and assessing their relative importance in the blackout factor are discussed. The model, besides providing estimates of spread-F occurrence on a worldwide basis, which will be of value in the engineering of HF and VHF communications, also furnishes a means of further checking the irregularity incremental electron density model on which it is based. (author)

A Decentralized Multi-Agent-Based Approach for Low Voltage Microgrid Restoration

Directory of Open Access Journals (Sweden)

Ebrahim Rokrok

2017-09-01

Full Text Available Although a well-organized power system is less subject to blackouts, the existence of a proper restoration plan is nevertheless still essential. The goal of a restoration plan is to bring the power system back to its normal operating conditions in the shortest time after a blackout occurs and to minimize the impact of the blackout on society. This paper presents a decentralized multi-agent system (MAS-based restoration method for a low voltage (LV microgrid (MG. In the proposed method, the MG local controllers are assigned to the specific agents who interact with each other to achieve a common decision in the restoration procedure. The evaluation of the proposed decentralized technique using a benchmark low-voltage MG network demonstrates the effectiveness of the proposed restoration plan.

CATACLYSMIC POLARITY SHIFT IS U.S. NATIONAL SECURITY PREPARED FOR THE NEXT GEOMAGNETIC POLE REVERSAL

Science.gov (United States)

2015-12-01

impacts of a long-term electrical blackout would extend for months, possibly leading to food starvation and anarchy in the regions hit hardest by the CME...the 60 million Americans without power would be very vulnerable to starvation .85 Defeating the cascading effects of a total electrical blackout...could be common as the magnetic field weakens, triggering less reliability for critical systems used in war and during peacetime operations. In

Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

Energy Technology Data Exchange (ETDEWEB)

Hedayat, Afshin [Reactor and Nuclear Safety School, Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of)

2017-08-15

In this paper, a complete station blackout (SBO) or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR). The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank), safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

Simulation and transient analyses of a complete passive heat removal system in a downward cooling pool-type material testing reactor against a complete station blackout and long-term natural convection mode using the RELAP5/3.2 code

Directory of Open Access Journals (Sweden)

Afshin Hedayat

2017-08-01

Full Text Available In this paper, a complete station blackout (SBO or complete loss of electrical power supplies is simulated and analyzed in a downward cooling 5-MW pool-type Material Testing Reactor (MTR. The scenario is traced in the absence of active cooling systems and operators. The code nodalization is successfully benchmarked against experimental data of the reactor's operating parameters. The passive heat removal system includes downward water cooling after pump breakdown by the force of gravity (where the coolant streams down to the unfilled portion of the holdup tank, safety flapper opening, flow reversal from a downward to an upward cooling direction, and then the upward free convection heat removal throughout the flapper safety valve, lower plenum, and fuel assemblies. Both short-term and long-term natural core cooling conditions are simulated and investigated using the RELAP5 code. Short-term analyses focus on the safety flapper valve operation and flow reversal mode. Long-term analyses include simulation of both complete SBO and long-term operation of the free convection mode. Results are promising for pool-type MTRs because this allows operators to investigate RELAP code abilities for MTR thermal–hydraulic simulations without any oscillation; moreover, the Tehran Research Reactor is conservatively safe against the complete SBO and long-term free convection operation.

Selection, design, qualification, testing, and reliability of emergency diesel generator units used as Class 1E onsite electric power systems at nuclear power plants

International Nuclear Information System (INIS)

1992-04-01

This guide has been prepared for the resolution of Generic Safety Issue B-56, ''Diesel Generator Reliability,'' and is related to Unresolved Safety Issue (USI) A-44, ''Station Blackout.'' The resolution of USI A-44 established a need for an emergency diesel generator (EDG) reliability program that has the capability to achieve and maintain the emergency diesel generator reliability levels in the range of 0.95 per demand or better to cope with station blackout

What Happened to Our Environment and Mental Health as a Result of Hurricane Sandy?

Science.gov (United States)

Lin, Shao; Lu, Yi; Justino, John; Dong, Guanghui; Lauper, Ursula

2016-06-01

This study describes findings of the impacts of Hurricane Sandy on environmental factors including power outages, air quality, water quality, and weather factors and how these affected mental health during the hurricane. An ecological study was conducted at the county level to describe changes in environmental factors-especially power outages-and their relationships to emergency department (ED) visits for mental health problems by use of a Poisson regression model. We found that many environmental hazards occurred as co-exposures during Hurricane Sandy in addition to flooding. Mental health ED visits corresponded with the peak of maximum daily power blackouts, with a 3-day lag, and were positively associated with power blackouts in Bronx (prevalence ratio [PR]: 8.82, 95% confidence interval [CI]: 1.27-61.42) and Queens (PR: 2.47, 95% CI: 1.05-5.82) counties. A possible dose-response relationship was found between the quantile of maximum blackout percentage and the risk of mental health in the Bronx. We found that multiple co-environmental hazards occurred during Hurricane Sandy, especially power blackouts that mediated this disaster's impacts. The effects of power outage on mental health had large geographic variations and were substantial, especially in communities with low sociodemographic status. These findings may provide new insights for future disaster response and preparedness efforts. (Disaster Med Public Health Preparedness. 2016;10:314-319).

Saving electricity in a hurry. Dealing with temporary shortfalls in electricity supplies

Energy Technology Data Exchange (ETDEWEB)

none

2005-07-01

Blackouts are normally the result of imbalances in electricity supply and demand. A brief blackout is mostly an inconvenience. But persistent shortfalls ? those lasting days, weeks, or months ? can cause economic disruption and danger to human life in our technology-rich societies. Saving Electricity in a Hurry describes some of the recent power shortfalls, from Norway to New Zealand, from Tokyo to Arizona and the policies these regions used to quickly reduce their power consumption. How did the whole country of Sweden cut its power consumption by 4% in only three days? How did California save 14% in only a few months? While the temporary shortfalls in electricity supplies described in this book are relatively rare events, they disproportionately shape future energy policies. Saving Electricity in a Hurry shows that countries can quickly reduce electricity consumption without harming the economy as much as blackouts or unplanned curtailments. The strategies are diverse, unique and often surprisingly cheap. They include mass media campaigns ? where a good joke can save a Megawatt ? improvements in equipment efficiency and quickly adjusting electricity prices. This book explains how California replaced a million traffic signals with energy-saving models, how millions of Tokyo residents raised their thermostat settings, and how New Zealanders took shorter showers, all quickly enough to help avoid imminent blackouts. Finally, it connects these policies to the traditional goal of ?saving electricity slowly?.

Handbook of electrical power system dynamics modeling, stability, and control

CERN Document Server

Eremia, Mircea

2013-01-01

Complete guidance for understanding electrical power system dynamics and blackouts This handbook offers a comprehensive and up-to-date treatment of power system dynamics. Addressing the full range of topics, from the fundamentals to the latest technologies in modeling, stability, and control, Handbook of Electrical Power System Dynamics provides engineers with hands-on guidance for understanding the phenomena leading to blackouts so they can design the most appropriate solutions for a cost-effective and reliable operation. Focusing on system dynamics, the book details

Utilization of Relap 5 computer code for analyzing thermohydraulic projects

International Nuclear Information System (INIS)

Silva Filho, E.

1987-01-01

This work deals with the design of a scaled test facility of a typical pressurized water reactor plant of the 1300 MW (electric) class. A station blackout has been choosen to investigate the thermohydraulic behaviour of the the test facility in comparison to the reactor plant. The computer code RELAPS/MOD1 has been utilized to simulate the blackout and to compare the test facility behaviour with the reactor plant one. The results demonstrate similar thermohydraulic behaviours of the two systems. (author) [pt

Application of Advanced Wide Area Early Warning Systems with Adaptive Protection

Energy Technology Data Exchange (ETDEWEB)

Blumstein, Carl [Univ. of California, Berkeley, CA (United States); Cibulka, Lloyd [Univ. of California, Berkeley, CA (United States); Thorp, James [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Centeno, Virgilio [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); King, Roger [Mississippi State Univ., Mississippi State, MS (United States); Reeves, Kari [Mississippi State Univ., Mississippi State, MS (United States); Ashrafi, Frank [Southern California Edison Co., Rosemead, CA (United States); Madani, Vahid [Pacific Gas & Electric Co., San Francisco, CA (United States)

2014-09-30

Recent blackouts of power systems in North America and throughout the world have shown how critical a reliable power system is to modern societies, and the enormous economic and societal damage a blackout can cause. It has been noted that unanticipated operation of protection systems can contribute to cascading phenomena and, ultimately, blackouts. This project developed and field-tested two methods of Adaptive Protection systems utilizing synchrophasor data. One method detects conditions of system stress that can lead to unintended relay operation, and initiates a supervisory signal to modify relay response in real time to avoid false trips. The second method detects the possibility of false trips of impedance relays as stable system swings “encroach” on the relays’ impedance zones, and produces an early warning so that relay engineers can re-evaluate relay settings. In addition, real-time synchrophasor data produced by this project was used to develop advanced visualization techniques for display of synchrophasor data to utility operators and engineers.

Improving the Transmission System Reliability for the 154kV Radial Network Operation

Energy Technology Data Exchange (ETDEWEB)

Choo, Jin Boo; Yoo, Myeong Ho; Yoon, Young Beum; Kim, Tae Won [Korea Electric Power Research Institute, Taejon (Korea, Republic of); Lee, Gi Won; Chung, Beom Jin; Jung, Jung Won; Park, Kyu Hyun; Lee, Myung Hee; Kim, Hyun Jong; Kim, Chae Hee [KEYIN CO., (Korea, Republic of)

1996-12-31

Analyzing that 154kV radial network current ed operated, we developed Automatic Power Reconfiguration System(APRS) which restore blackout area. It consists of special data acquisition system(DAU) and central monitoring system for reason of protecting currently operating power system. In addition, it communicates using optical communication network for high speed data transmission and accuracy. An Accuracy of operation and stability of the developed system is tested using Real Time Digital Simulator in 3-bus equivalent model system. In An Outage case, our developed system can restore a blackout area in three second. An ability of the restoration of a blackout was verified by simulations. For the field test, the developed system was set up at SINCHON S/S, SESOMUN S/S, SINDANG S/S and MAJANG S/S governed by Seoul Power Transmission Center. If the system reliability is proved for a one year test in real power system, application of the system will be extended to the other substations.

Emergency Diesel Generation System Surveillance Test Policy Optimization Through Genetic Algorithms Using Non-Periodic Intervention Frequencies and Seasonal Constraints

International Nuclear Information System (INIS)

Lapa, Celso M.F.; Pereira, Claudio M.N.A.; Frutuoso e Melo, P.F.

2002-01-01

Nuclear standby safety systems must frequently, be submitted to periodic surveillance tests. The main reason is to detect, as soon as possible, the occurrence of unrevealed failure states. Such interventions may, however, affect the overall system availability due to component outages. Besides, as the components are demanded, deterioration by aging may occur, penalizing again the system performance. By these reasons, planning a good surveillance test policy implies in a trade-off between gains and overheads due to the surveillance test interventions. In order maximize the systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic tests scheme. The optimization problem becomes, however, more complex. Hence, the use of a powerful optimization technique, such as GAs, is required. Some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem. The Emergency Diesel Generation System (EDGS) of a Nuclear Power Plant (N-PP) is a good example for demonstrating the introduction of seasonal constraints in the optimization problem. This system is responsible for power supply during an external blackout. Therefore, it is desirable during periods of high blackout probability to maintain the system availability as high as possible. Previous applications have demonstrated the robustness and effectiveness of the methodology. However, no seasonal constraints have ever been imposed. This work aims at investigating the application of such methodology in the Angra-II Brazilian NPP EDGS surveillance test policy optimization, considering the blackout probability

77 FR 16175 - Station Blackout

Science.gov (United States)

2012-03-20

... of the near- term actions based on lessons-learned stemming from the March 2011 Fukushima Dai-ichi... http://www.regulations.gov and search for documents filed under Docket ID NRC- 2011-0299. Address.... Fukushima Dai-ichi Event and the NRC Regulatory Response III. Background A. General Design Criteria 2 and 17...

Resolution of GSI B-56 - Emergency diesel generator reliability

International Nuclear Information System (INIS)

Serkiz, A.W.

1989-01-01

The need for an emergency diesel generator (EDG) reliability program has been established by 10 CFR Part 50, Section 50.63, Loss of All Alternating Current Power, which requires that licensees assess their station blackout coping and recovery capability. EDGs are the principal emergency ac power sources for avoiding a station blackout. Regulatory Guide 1.155, Station Blackout, identifies a need for (1) a nuclear unit EDG reliability level of at least 0.95, and (2) an EDG reliability program to monitor and maintain the required EDG reliability levels. NUMARC-8700, Guidelines and Technical Bases for NUMARC Initiatives Addressing Station Blackout at Light Water Reactors, also provides guidance on such needs. The resolution of GSI B-56, Diesel Reliability will be accomplished by issuing Regulatory Guide 1.9, Rev. 3, Selection, Design, Qualification, Testing, and Reliability of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Plants. This revision will integrate into a single regulatory guide pertinent guidance previously addressed in R.G. 1.9, Rev. 2, R.G. 1.108, and Generic Letter 84-15. R.G. 1.9 has been expanded to define the principal elements of an EDG reliability program for monitoring and maintaining EDG reliability levels selected for SBO. In addition, alert levels and corrective actions have been defined to detect a deteriorating situation for all EDGs assigned to a particular nuclear unit, as well as an individual problem EDG

Nuclear energy + solar energy, why not?

International Nuclear Information System (INIS)

Hernandez C, I.; Nelson E, P.

2016-09-01

Clean energies such as nuclear and solar are part of the solution to the energy dependence that we face today and also help us to reduce the greenhouse gas emissions, thus avoiding a global average temperature increase that is irreversible and harmful to all living beings on the planet. Independently the nuclear and solar energies have had a great development in recent years, so in this work we set ourselves the task of creating a synergy between them. First, we conducted a survey of different people involved in the area of energy (energy efficiency, clean energy and renewable sources) in order to know if the area of which they are part influences with respect to the impression that they have of safety in terms of supply, return on investment and safety to the health and environment of another energy source for which we use a correlation analysis. With the results obtained we propose to use photo thermic solar energy as a support to reduce the frequency of accidents by station blackout and we perform the analysis of the combination using the methodology of Probabilistic Analysis of Security with the help of SAPHIRE 7 software to realize the event trees by station blackout of a nuclear power plant and faults for a photo-thermal solar plant. Finally, the decrease in the probability of station blackout from the proposed combination is quantified. The results were favorable to indicate that the probability of station blackout is reduced in half and that is why is suggested to continue studying the combination. (Author)

Nuclear energy + solar energy, why not?; Energia nuclear + energia solar, por que no?

Energy Technology Data Exchange (ETDEWEB)

Hernandez C, I.; Nelson E, P., E-mail: ihernandezc91@hotmail.com [UNAM, Facultad de Ingenieria, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

2016-09-15

Clean energies such as nuclear and solar are part of the solution to the energy dependence that we face today and also help us to reduce the greenhouse gas emissions, thus avoiding a global average temperature increase that is irreversible and harmful to all living beings on the planet. Independently the nuclear and solar energies have had a great development in recent years, so in this work we set ourselves the task of creating a synergy between them. First, we conducted a survey of different people involved in the area of energy (energy efficiency, clean energy and renewable sources) in order to know if the area of which they are part influences with respect to the impression that they have of safety in terms of supply, return on investment and safety to the health and environment of another energy source for which we use a correlation analysis. With the results obtained we propose to use photo thermic solar energy as a support to reduce the frequency of accidents by station blackout and we perform the analysis of the combination using the methodology of Probabilistic Analysis of Security with the help of SAPHIRE 7 software to realize the event trees by station blackout of a nuclear power plant and faults for a photo-thermal solar plant. Finally, the decrease in the probability of station blackout from the proposed combination is quantified. The results were favorable to indicate that the probability of station blackout is reduced in half and that is why is suggested to continue studying the combination. (Author)

Quantifying the daily economic impact of extreme space weather due to failure in electricity transmission infrastructure

Science.gov (United States)

Oughton, Edward J.; Skelton, Andrew; Horne, Richard B.; Thomson, Alan W. P.; Gaunt, Charles T.

2017-01-01

Extreme space weather due to coronal mass ejections has the potential to cause considerable disruption to the global economy by damaging the transformers required to operate electricity transmission infrastructure. However, expert opinion is split between the potential outcome being one of a temporary regional blackout and of a more prolonged event. The temporary blackout scenario proposed by some is expected to last the length of the disturbance, with normal operations resuming after a couple of days. On the other hand, others have predicted widespread equipment damage with blackout scenarios lasting months. In this paper we explore the potential costs associated with failure in the electricity transmission infrastructure in the U.S. due to extreme space weather, focusing on daily economic loss. This provides insight into the direct and indirect economic consequences of how an extreme space weather event may affect domestic production, as well as other nations, via supply chain linkages. By exploring the sensitivity of the blackout zone, we show that on average the direct economic cost incurred from disruption to electricity represents only 49% of the total potential macroeconomic cost. Therefore, if indirect supply chain costs are not considered when undertaking cost-benefit analysis of space weather forecasting and mitigation investment, the total potential macroeconomic cost is not correctly represented. The paper contributes to our understanding of the economic impact of space weather, as well as making a number of key methodological contributions relevant for future work. Further economic impact assessment of this threat must consider multiday, multiregional events.

Assessing the Cost of Large-Scale Power Outages to Residential Customers.

Science.gov (United States)

Baik, Sunhee; Davis, Alexander L; Morgan, M Granger

2018-02-01

Residents in developed economies depend heavily on electric services. While distributed resources and a variety of new smart technologies can increase the reliability of that service, adopting them involves costs, necessitating tradeoffs between cost and reliability. An important input to making such tradeoffs is an estimate of the value customers place on reliable electric services. We develop an elicitation framework that helps individuals think systematically about the value they attach to reliable electric service. Our approach employs a detailed and realistic blackout scenario, full or partial (20 A) backup service, questions about willingness to pay (WTP) using a multiple bounded discrete choice method, information regarding inconveniences and economic losses, and checks for bias and consistency. We applied this method to a convenience sample of residents in Allegheny County, Pennsylvania, finding that respondents valued a kWh for backup services they assessed to be high priority more than services that were seen as low priority ($0.75/kWh vs. $0.51/kWh). As more information about the consequences of a blackout was provided, this difference increased ($1.2/kWh vs. $0.35/kWh), and respondents' uncertainty about the backup services decreased (Full: $11 to $9.0, Partial: $13 to $11). There was no evidence that the respondents were anchored by their previous WTP statements, but they demonstrated only weak scope sensitivity. In sum, the consumer surplus associated with providing a partial electric backup service during a blackout may justify the costs of such service, but measurement of that surplus depends on the public having accurate information about blackouts and their consequences. © 2017 Society for Risk Analysis.

Study on introduction of SN transition type FCL into distribution systems

International Nuclear Information System (INIS)

Kameda, Hideyuki; Uemura, Satoshi; Ichinose, Ataru

2013-01-01

Highlights: •We describe the arrangement of SNFCL into a present and a future distribution system. •The FCLs near loop-switches can prevent a blackout against a fault within the loop. •The FCLs enable us to enhance the flexibility of the system configuration. -- Abstract: The suitable introduction method of SN transition type superconducting fault current limiter (SNFCL) into a typical 6.6-kVdistribution system in Japan is described. A present distribution system is operated in the radial configuration and aged equipment with the isolated neutral system. An introduction of the FCLs into this system could expect to become a countermeasure against a short-circuit when introducing distributed generations in a future looped distribution system, the entire system will go into a blackout without any countermeasures, when a fault occurs within the looped system. But the introduction of the FCLs is expected to localize a blackout and to enhance the flexibility of a system configuration. In order to achieve the above-mentioned purposes of the introduction of the FCLs, the setting method of the parameters which a user should set is proposed using the transient analysis model of the SNFCL which we have ever developed

A FMM-FFT accelerated hybrid volume surface integral equation solver for electromagnetic analysis of re-entry space vehicles

KAUST Repository

Yücel, Abdulkadir C.

2014-07-01

Space vehicles that re-enter the atmosphere often experience communication blackout. The blackout occurs when the vehicle becomes engulfed in plasma produced by interactions between the vehicle surface and the atmosphere. The plasma often is concentrated in a relatively thin shell around the vehicle, with higher densities near its nose than rear. A less structured, sometimes turbulent plasma wake often trails the vehicle. The plasma shell severely affects the performance of side-mounted antennas as it alters their characteristics (frequency response, gain patterns, axial ratio, and impedance) away from nominal, free-space values, sometimes entirely shielding the antenna from the outside world. The plasma plume/turbulent wake similarly affect the performance of antennas mounted at the back of the vehicle. The electromagnetic characteristics of the thin plasma shell and plume/turbulent wake heavily depend on the type of re-entry trajectory, the vehicle\\'s speed, angles of attack, and chemical composition, as well as environmental conditions. To analyze the antennas\\' performance during blackout and to design robust communication antennas, efficient and accurate simulation tools for charactering the antennas\\' performance along the trajectory are called for.

Reliability of the grid as function of power flow and configuration during maintenance

International Nuclear Information System (INIS)

Kovacs, Z.; Hlavac, P.; Janicek, F.

2012-01-01

The paper describes using of PSA (Probabilistic Safety Assessment) for analysis of the partial and total blackout of the grid for different power flows and configuration of the grid given by the preventive maintenance activities. The method uses event and fault tree analysis in combination with the dynamic stability analysis of the grid. The event trees model the grid response to the initiating event of the accident. The fault trees are used to model the reliability of the substation protection systems. Different end states of the event trees are simulated on the basis of dynamic stability analysis, as safe and emergency state, partial and total blackout. Minimal cut sets are generated, importance measures (Fussel-Vesely importance, risk increase factor and risk decrease factors) are calculated for the total and partial blackout. The most dominant initiating events and component failures are identified from the risk point of view. Using the PSA the model, of the transmission grid is being developed. The model can be implemented into the risk monitor software to analyze the risk for different configurations of the grid and to support the operation and the maintenance activities. (Authors)

Dispersed Trading and the Prevention of Market Failure

DEFF Research Database (Denmark)

Porter, David C.; Tanggaard, Carsten; G. Weaver, Daniel

With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight into thi......With augmented demands on power grids resulting in longer and larger blackouts combined with heightened concerns of terrorist attacks, trading institutions and policy makers have widened their search for systems that avoid market failure during these disturbing events. We provide insight...... combined with widely dispersed trading locations may be a viable means of protection against market failure during massive power disruptions or terrorist attacks....

Comparison of Severe Accident Results Among SCDAP/RELAP5, MAAP, and MELCOR Codes

International Nuclear Information System (INIS)

Wang, T.-C.; Wang, S.-J.; Teng, J.-T.

2005-01-01

This paper demonstrates a large-break loss-of-coolant accident (LOCA) sequence of the Kuosheng nuclear power plant (NPP) and station blackout sequence of the Maanshan NPP with the SCDAP/RELAP5 (SR5), Modular Accident Analysis Program (MAAP), and MELCOR codes. The large-break sequence initiated with double-ended rupture of a recirculation loop. The main steam isolation valves (MSIVs) closed, the feedwater pump tripped, the reactor scrammed, and the assumed high-pressure and low-pressure spray systems of the emergency core cooling system (ECCS) were not functional. Therefore, all coolant systems to quench the core were lost. MAAP predicts a longer vessel failure time, and MELCOR predicts a shorter vessel failure time for the large-break LOCA sequence. The station blackout sequence initiated with a loss of all alternating-current (ac) power. The MSIVs closed, the feedwater pump tripped, and the reactor scrammed. The motor-driven auxiliary feedwater system and the high-pressure and low-pressure injection systems of the ECCS were lost because of the loss of all ac power. It was also assumed that the turbine-driven auxiliary feedwater pump was not functional. Therefore, the coolant system to quench the core was also lost. MAAP predicts a longer time of steam generator dryout, time interval between top of active fuel and bottom of active fuel, and vessel failure time than those of the SR5 and MELCOR predictions for the station blackout sequence. The three codes give similar results for important phenomena during the accidents, including SG dryout, core uncovery, cladding oxidation, cladding failure, molten pool formulation, debris relocation to the lower plenum, and vessel head failure. This paper successfully demonstrates the large-break LOCA sequence of the Kuosheng NPP and the station blackout sequence of the Maanshan NPP

Leveraging Active Knit Technologies for Aerospace Pressure Suit Applications

Data.gov (United States)

National Aeronautics and Space Administration — Anti-Gravity Suits (AGS) are garments used in astronautics to prevent crew from experiencing orthostatic intolerance (OI) and consequential blackouts while...

Plaadid / Tui Hirv

Index Scriptorium Estoniae

Hirv, Tui, 1984-

2007-01-01

Uutest heliplaatidest Andrea Bocelli "Vivere. The Best Of", Britney Spears "Blackout", John Fogerty "Revival", Bat For Lashes "Fur And Gold", Jimmy Eat World "Chase This Light", Duran Duran "Red Carpet Massacre"

Rohypnol

Science.gov (United States)

... Jobs Sports Expert Answers (Q&A) Staying Safe Videos for ... Because it can cause extreme drowsiness (or "blackouts"), it is often used in date rapes. Sometimes Called: roofies, roach, forget-me pill, date ...

Development of expert system for fault diagnosis and restoration at substations

Energy Technology Data Exchange (ETDEWEB)

Choo, Jin Boo; Kwon, Tae Won; Yoon, Yong Beum; Park, Sung Taek [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Park, Young Moon; Lee, Heung Jae [Electrical Engineering and Science Research Institute (Korea, Republic of)

1996-12-31

When a fault occurs in power systems, the operators have to make precise judgements on the situation and take appropriate actions rapidly to protect the system and minimize the black-out area. However, the larger and the more complex the power systems become, the more difficult it becomes to expect the effective actions of human operators. Therefore, it is a very important issue to support the operators of the local power systems in the case of various faults. We develop an expert system for fault diagnosis and reconfiguration of local power system. The expert system has a capability of identifying the location and the type of faults, the black-out area, and an appropriate reconfiguration procedure for re-energizing or minimizing the service interruption (author). 35 refs., 45 figs.

Development of expert system for fault diagnosis and restoration at substations

Energy Technology Data Exchange (ETDEWEB)

Choo, Jin Boo; Kwon, Tae Won; Yoon, Yong Beum; Park, Sung Taek [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center; Park, Young Moon; Lee, Heung Jae [Electrical Engineering and Science Research Institute (Korea, Republic of)

1995-12-31

When a fault occurs in power systems, the operators have to make precise judgements on the situation and take appropriate actions rapidly to protect the system and minimize the black-out area. However, the larger and the more complex the power systems become, the more difficult it becomes to expect the effective actions of human operators. Therefore, it is a very important issue to support the operators of the local power systems in the case of various faults. We develop an expert system for fault diagnosis and reconfiguration of local power system. The expert system has a capability of identifying the location and the type of faults, the black-out area, and an appropriate reconfiguration procedure for re-energizing or minimizing the service interruption (author). 35 refs., 45 figs.

Switzerland - its position within a liberalised European power market

International Nuclear Information System (INIS)

Kiener, E.

2005-01-01

This article takes a look at the situation in Switzerland shortly before parliamentary discussions on the liberalisation of Switzerland's electricity market. In particular the interconnection of Switzerland's electricity supply system with that of the rest of Europe is discussed. The power black-out that occurred in Italy in September 2003 is looked at. In particular, its relevance to power supply infrastructures is discussed and the fast-changing international configurations that are resulting from the liberalisation of electricity markets are looked at. Questions of international power transfer capacities and their allocation are looked at in detail in the light of the occurrences in 2003. The lessons that must be learned from the blackout are discussed and Switzerland's geographical position as an important hub of the European power transfer system are considered

Validation Method of a Telecommunications Blackout Attack

National Research Council Canada - National Science Library

Amado, Joao; Nunes, Paulo

2005-01-01

..., and to obtain the maximum disruptive effect over the services. The proposed method uses a top-down approach, starting on the service level and ending on the different network elements that can be identified in the end as the targets for the attack.

As Blood Alcohol Content (BAC) Increases, So Does Impairment | NIH MedlinePlus the Magazine

Science.gov (United States)

... 30% Severe Impairment – 0.16 - 0.30% Speech, memory, coordination, attention, reaction time, balance significantly impaired All driving-related skills dangerously impaired Judgement and decision making dangerously impaired Blackouts (amnesia) Vomiting and other signs ...

Applications of phasor measurement units (PMUs) in electric power ...

African Journals Online (AJOL)

user

mitigating blackouts and learning the real time behavior of the power system. ...... This literature takes advantage of PMUs and decision trees (DTs) to develop a ... from which the dominant machines are extracted based on dynamic coherency.

Women and Diabetes

Medline Plus

Full Text Available ... tips to help you manage your diabetes. Food Safety for People with Diabetes Your Glucose Meter - easy- ... to Store your Insulin during Storms and Blackouts Safety Information for Diabetes Medicines and Devices Beware of ...

Air ingression calculations for selected plant transients using MELCOR

International Nuclear Information System (INIS)

Kmetyk, L.N.

1994-01-01

Two sets of MELCOR calculations have been completed studying the effects of air ingression on the consequences of various severe accident scenarios. One set of calculations analyzed a station blackout with surge line failure prior to vessel breach, starting from nominal operating conditions; the other set of calculations analyzed a station blackout occurring during shutdown (refueling) conditions. Both sets of analyses were for the Surry plant, a three-loop Westinghouse PWR. For both accident scenarios, a basecase calculation was done, and then repeated with air ingression from containment into the core region following core degradation and vessel failure. In addition to the two sets of analyses done for this program, a similar air-ingression sensitivity study was done as part of a low-power/shutdown PRA, with results summarized here; that PRA study also analyzed a station blackout occurring during shutdown (refueling) conditions, but for the Grand Gulf plant, a BWR/6 with Mark III containment. These studies help quantify the amount of air that would have to enter the core region to have a significant impact on the severe accident scenario, and demonstrate that one effect, of air ingression is substantial enhancement of ruthenium release. These calculations also show that, while the core clad temperatures rise more quickly due to oxidation with air rather than steam, the core also degrades and relocates more quickly, so that no sustained, enhanced core heatup is predicted to occur with air ingression

Kinos voolab naftat / Tiit Tuumalu

Index Scriptorium Estoniae

Tuumalu, Tiit, 1971-

2010-01-01

Filmistuudio Nafta lühifilmide kava 1. oktoobrist 2010 Tallinna kinos Artis. Kavasse kuuluvad uued linateosed: Heleri Saariku "Näkilugu" ja Margus Paju "Blackout" ning Priit Pääsukese "Must Peeter" (2008), Peeter Sauteri novelli "Must notsu" ekraniseering

"Musta Peetri" stuudio Nafta näitab uusi lühifilme / Andres Laasik

Index Scriptorium Estoniae

Laasik, Andres, 1960-2016

2010-01-01

Filmistuudio Nafta lühifilmide kava 1. oktoobrist 2010 Tallinna kinos Artis. Kavasse kuuluvad uued linateosed Heleri Saariku "Näkilugu" ja Margus Paju "Blackout" ning Priit Pääsukese "Must Peeter" (2008), Peeter Sauteri novelli "Must notsu" ekraniseering

Women and Alcohol

Science.gov (United States)

... may be more vulnerable to brain damage than teen boys who drink. Women also may be more susceptible than men to alcohol-related blackouts, defined as periods of memory loss of events during intoxication without loss of consciousness. ...

Core damage frequency prespectives for BWR 3/4 and Westinghouse 4-loop plants based on IPE results

International Nuclear Information System (INIS)

Dingman, S.; Camp, S.; LaChance, J.; Mary Drouin

1995-01-01

This paper discusses the core damage frequency (CDF) insights gained by analyzing the results of the Individual Plant Examinations (IPES) for two groups of plants: boiling water reactor (BWR) 3/4 plants with Reactor Core Isolation Cooling systems, and Westinghouse 4-loop plants. Wide variability was observed for the plant CDFs and for the CDFs of the contributing accident classes. On average, transients-with loss of injection, station blackout sequences, and transients with loss of decay heat removal are important contributors for the BWR 3/4 plants, while transients, station blackout sequences, and loss-of-coolant accidents are important for the Westinghouse 4-loop plants. The key factors that contribute to the variability in the results are discussed. The results are often driven by plant-specific design and operational characteristics, but differences in modeling approaches are also important for some accident classes

A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle

International Nuclear Information System (INIS)

Gao, Xiaotian; Jiang, Binhao

2015-01-01

In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods

Alternative cooling water flow path for RHR heat exchanger and its effect on containment response during extended station blackout for Chinshan BWR-4 plant

Energy Technology Data Exchange (ETDEWEB)

Yuann, Yng-Ruey, E-mail: ryyuann@iner.gov.tw

2016-04-15

Highlights: • Motivating alternative RHR heat exchanger tube-side flow path and determining required capacity. • Calculate NSSS and containment response during 24-h SBO for Chinshan BWR-4 plant. • RETRAN and GOTHIC models are developed for NSSS and containment, respectively. • Safety relief valve blowdown flow and energy to drywell are generated by RETRAN. • Analyses are performed with and without reactor depressurization, respectively. - Abstract: The extended Station Blackout (SBO) of 24 h has been analyzed with respect to the containment response, in particular the suppression pool temperature response, for the Chinshan BWR-4 plant of MARK-I containment. The Chinshan plant, owned by Taiwan Power Company, has twin units with rated core thermal power of 1840 MW each. The analysis is aimed at determining the required alternative cooling water flow capacity for the residual heat removal (RHR) heat exchanger when its tube-side sea water cooling flow path is blocked, due to some reason such as earthquake or tsunami, and is switched to the alternative raw water source. Energy will be dissipated to the suppression pool through safety relief valves (SRVs) of the main steam lines during SBO. The RETRAN model is used to calculate the Nuclear Steam Supply System (NSSS) response and generate the SRV blowdown conditions, including SRV pressure, enthalpy, and mass flow rate. These conditions are then used as the time-dependent boundary conditions for the GOTHIC code to calculate the containment pressure and temperature response. The shaft seals of the two recirculation pumps are conservatively assumed to fail due to loss of seal cooling and a total leakage flow rate of 36 gpm to the drywell is included in the GOTHIC model. Based on the given SRV blowdown conditions, the GOTHIC containment calculation is performed several times, through the adjustment of the heat transfer rate of the RHR heat exchanger, until the criterion that the maximum suppression pool temperature

Stuart Brisley etendused inimliku ja kunstipärase piiril / Andri Ksenofontov

Index Scriptorium Estoniae

Ksenofontov, Andri, 1962-

2009-01-01

Stuart Brisley näitus "Crossings" ("Ületamised") Tallinna Linnagaleriis 19- sept. - 4. oktoobrini. Heli- ja valgusinstallatsioonist "Touching Black Ice" Titanicu hukkumisest 1912. a. 15. aprillil. Videoinstallatsioonist "Blackout" Estonia hukkumisest 1994. a. 28. septembril. Näitusega kaasnevast kataloogist. Stuart Brisley loomingust

Vulnerability of the Nordic power system. Executive summary

International Nuclear Information System (INIS)

Doorman, Gerard; Kjoeelle, Gerd; Uhlen, Kjetil; Huse, Einar Staale; Flataboe, Nils

2004-05-01

The objective of the analysis is to identify the vulnerability of the Nordic power system, identify barriers to reduce vulnerability in a Nordic context and to propose possible actions. The study focuses on vulnerability with respect to energy shortage, capacity shortage and power system failures. Vulnerability is defined with respect to the unwanted situations ''High prices'', ''Curtailment'' and ''Blackouts''. The main tool of the study is risk analysis, where risk is a result of the probability of an event and its consequences. With respect to energy shortage, the system is in a medium risk state. For the present system the probability of a situation like the 2002/03 winter or considerably worse is once every ten years. Under the assumption that power production increases with increasing demand, the situation will be similar towards 2010. In the opposite case, the risk of extremely high prices increases. With respect to capacity shortage, the system is in a low risk state. This is partly due to actions already taken by the TSOs. The risk state will slightly deteriorate towards 2010. With respect to blackouts, the system is in a medium risk state. This is due to the fact that large blackouts in Southern Scandinavia cannot be completely ruled out. Such blackouts involve many consumers resulting in major or potentially even critical consequences. However this is not different from the situation before deregulation. There are no indications that the situation will become worse towards 2010, but there is uncertainty with regard to the effect of changed maintenance routines. Reductions in qualified technical personnel also gives reason for concern. The study identifies significant differences between the Nordic countries with respect to the framework for transmission system investment, system balancing, rules and price setting in the case of curtailment, congestion management and the handling of import and export. Recommended actions include reduction of regulatory

Electrical energy systems

CERN Document Server

El-Hawary, Mohamed E

2007-01-01

Features discussions ranging from the technical aspects of generation, transmission, distribution, and utilization to power system components, theory, protection, and the energy control center that offer an introduction to effects of deregulating electric power systems, blackouts and their causes, and minimizing their effects.

Klimaat, energieverbruik en bloem temperatuur bij twee Gerbera telers

NARCIS (Netherlands)

Vanthoor, B.H.E.; Tsafaras, I.

2018-01-01

This report provides an overview of the Gerbera companies -Holstein Flowers and Zuijderwijk Witzier. Both growers have a blackout screen, energy screen and an illumination system. Holstein Flowers dehumidifies the greenhouse air by means of blowing in heated outside air (using air ducts) and

The Impact of the Topology on Cascading Failures in a Power Grid Model

NARCIS (Netherlands)

Koç, Y.; Warnier, M.; Mieghem, P. van; Kooij, R.E.; Brazier, F.M.T.

2014-01-01

Cascading failures are one of the main reasons for large scale blackouts in power transmission grids. Secure electrical power supply requires, together with careful operation, a robust design of the electrical power grid topology. Currently, the impact of the topology on grid robustness is mainly

Alcohol Problems in Alaska Natives: Lessons from the Inuit

Science.gov (United States)

Seale, J. Paul; Shellenberger, Sylvia; Spence, John

2006-01-01

In this Alaska Native study, cultural "insiders" analyzed problems associated with increased alcohol availability, factors which have reduced alcohol-related problems, and ideas for improving treatment in an Inuit community. Participants described frequent bingeing, blackouts, family violence, suicide, loss of child custody, and feelings…

Decentralized planning of energy demand for the management of robustness and discomfort

NARCIS (Netherlands)

Pournaras, E.; Vasirani, M.; Kooij, R.E.; Aberer, K.

2014-01-01

The robustness of smart grids is challenged by unpredictable power peaks or temporal demand oscillations that can cause blackouts and increase supply costs. Planning of demand can mitigate these effects and increase robustness. However, the impact on consumers in regards to the discomfort they

Blackout: coal, climate and the last energy crisis

Energy Technology Data Exchange (ETDEWEB)

Heinberg, R. [Post Carbon Institute in California, CA (United States)

2009-07-15

Coal fuels more than 30 per cent of UK electricity production, and about 50 per cent in the US, providing a significant portion of total energy output. China and India's recent ferocious economic growth has been based almost entirely on coal-generated electricity. Coal currently looks like a solution to many of our fast-growing energy problems. However, while coal advocates are urging us full steam ahead, the increasing reliance on this dirtiest of all fossil fuels has crucial implications for energy policy, pollution levels, the global climate, world economy and geopolitics. Drawbacks to a coal-based energy strategy include: Scarcity - new studies suggest that the peak of world coal production may actually be less than two decades away; Cost - the quality of produced coal is declining, while the expense of transportation is rising, leading to spiralling costs and increasing shortages; and, Climate impacts - our ability to deal with the historic challenge of climate change may hinge on reducing coal consumption in future years.

49 CFR 390.5 - Definitions.

Science.gov (United States)

2010-10-01

... person's appearance in court, a plea of guilty or nolo contendere accepted by the court, the payment of a... related to long-term rehabilitation of damaged physical infrastructure or routine commercial deliveries..., explosion, blackout or other occurrence, natural or man-made, which interrupts the delivery of essential...

The NUREG-1150 probabilistic risk assessment for the Grand Gulf nuclear station

International Nuclear Information System (INIS)

Brown, T.D.; Breeding, R.J.; Jow, H.N.; Higgins, S.J.; Shiver, A.W.; Helton, J.C.

1992-01-01

This paper summarizes the findings of the probabilistic risk assessment (PRA) for Unit 1 of the Grand Gulf Nuclear Station performed in support of NUREG-1150. The emphasis is on the 'back-end' analyses, that is, the acident progression, source term, consequence analsyes, and risk results obtained when the results of these analyses are combined with the accident frequency analysis. The offsite risk from internal initiating events was found to be quite low, both with respect to the safety goals and to the other plants analyzed in NUREG-1150. The offsite risk is dominated by short-term station blackout plant damage states. The long-term blackout group and the anticiptated transients without scram (ATWS) group contribute considerably less to risk. Transients in which the power conversion system is unavailable are very minor contributors to risk. The low values for risk can be attributed to low core damage frequency, good emergency response, and plant features that reduce the potential source term. (orig.)

Designing Offshore Super Grid for the Combined Operation of Offshore Wind Farms and Hydro Storage

DEFF Research Database (Denmark)

Grimaldi, Armando; Chen, Zhe; Chen, Peiyuan

2009-01-01

The European commission decided in 2008 to reduce the dependency of imported primary energy sources and to promote the use of renewable energy. In particular, many offshore wind farms are planned in the North Sea between 2020 and 2030. Furthermore, the recent blackouts in Europe have shown that i...

Our Lyrics Will Not Be on Lockdown: An Arts Collective's Response to an Incarceration Nation

Science.gov (United States)

Green, Keisha

2010-01-01

Recognizing the unprecedented proliferation of prisons in the United States, Blackout Arts Collective (BAC), a grassroots organization working to empower communities of color through the arts, education, and activism, launched a national tour--"Lyrics on Lockdown (LOL): Slamming the Prison Industrial Complex." As a BAC member, I participated in…

Resource Efficient Scheduling, Optimization and Control.

NARCIS (Netherlands)

van den Akker, Marjan; Derksen, Christian; Kowalczyk, Ryszard; Mönch, Lars; Valogianni, Konstantina; van Heck, Erik; Zhang, Minjie

2014-01-01

This report documents the program and the outcomes of Dagstuhl Seminar 14181 "Multi-agent systems and their role in future energy grids". A number of recent events (e.g. Fukushima, Japan, and the largest blackout in history, India) have once again increased global attention on climate change and

Hydroponic Technology for Lily Flowers and Bulbs Production Using ...

African Journals Online (AJOL)

This experiment was carried out to investigate the potential of nutrient film technique (NFT) hydroponic system for flowers and bulbs production of the Asiatic hybrid lily cv. "Blackout" using rainwater and some common nutrient solutions (Hoagland No. 2 Basal Salt Mixture, Murashige and Skoog Basal Salt Mixture and ...

78 FR 6673 - National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion...

Science.gov (United States)

2013-01-30

..., Energy and Economic Impacts A. What are the air quality impacts? B. What are the cost impacts? C. What... will assist in stabilizing the grid during periods of instability, preventing electrical blackouts and... important programs that protect the reliability and stability of the national electric service grid. The use...

Investigation of the possibility of using residual heat reactor energy

Science.gov (United States)

Aminov, R. Z.; Yurin, V. E.; Bessonov, V. N.

2017-11-01

The largest contribution to the probable frequency of core damage is blackout events. The main component of the heat capacity at each reactor within a few minutes following a blackout is the heat resulting from the braking of beta-particles and the transfer of gamma-ray energy by the fission fragments and their decay products, which is known as the residual heat. The power of the residual heat changes gradually over a long period of time and for a VVER-1000 reactor is about 15-20 MW of thermal power over 72 hours. Current cooldown systems increase the cost of the basic nuclear power plants (NPP) funds without changing the amount of electricity generated. Such systems remain on standby, accelerating the aging of the equipment and accordingly reducing its reliability. The probability of system failure increases with the duration of idle time. Furthermore, the reactor residual heat energy is not used. A proposed system for cooling nuclear power plants involves the use of residual thermal power to supply the station’s own needs in emergency situations accompanied by a complete blackout. The thermal power of residual heat can be converted to electrical energy through an additional low power steam turbine. In normal mode, the additional steam turbine generates electricity, which makes it possible to ensure spare NPP and a return on the investment in the reservation system. In this work, experimental data obtained from a Balakovo NPP was analyzed to determine the admissibility of cooldown of the reactors through the 2nd circuit over a long time period, while maintaining high-level parameters for the steam generated by the steam generators.

Millstone 3 risk evaluation report. An overall review and evaluation of the Millstone Unit 3 probabilistic safety study

International Nuclear Information System (INIS)

Kelly, G.; Barrett, R.; Buslik, A.

1986-06-01

In 1981, the US Nuclear Regulatory Commission (NRC) requested Northeast Utilities to perform a design-specific probabilistic safety study (PSS) for Millstone Nuclear Power Station, Unit No. 3 (Millstone 3). In 1983, Northeast Utilities submitted the Millstone 3 Probabilistic Safety Study for review by the NRC staff. The NRC staff prepared the Millstone 3 Risk Evaluation Report, which discusses the findings regarding the PSS. The PSS estimates that the mean annual core damage frequency due to internal and external events is 5 x 10 -5 and 2 x 10 -5 , respectively. The NRC staff's Risk Evaluation Report estimates that the mean annual core damage frequency is about 2 x 10 -4 for internal events and lies between 1 x 10 -5 and 2 x 10 -4 for external events. The NRC staff estimates that station blackout dominates internal and external event core damage frequencies. The staff recommends that Northeast Utilities perform an engineering analysis on upgrading the diesel generator lube oil cooler anchorage system and on adding a manually operated, AC-independent containment spray system. The staff also recommends that Northeast Utilities prepare two emergency procedures (loss of room cooling and relay chatter due to an earthquake) to help reduce uncertainties. (Subsequent to the completion of this document, Northeast Utilities and the NRC staff have continued a dialogue regarding station blackout from events other than earthquakes. Both Northeast Utilities and the staff have performed additional evaluations, which have drawn their results closer together. Final requirements, if any, for the prevention or mitigation of station blackout from events other than earthquakes have not yet been determined.) 26 refs., 16 tabs

Market surveillance panel monitoring report on the IMO-administered electricity markets for the first 18 months (May 2002 - October 2003)

International Nuclear Information System (INIS)

Gorbet, F.; McFetridge, D.; Rusnov, T.

2003-01-01

The Market Surveillance Panel is an independent body appointed by Ontario's Independent Electricity Market Operator. The Panel's mandate is to monitor the behaviour in the marketplace, examine the behaviour of specific market participants, investigate design rules and operating procedures, and provide periodic reports on the state of the marketplace. This third period report covers the first 18 months of the Ontario electricity marketplace from May 1, 2002 to October 31, 2003. The report includes an overall assessment of the evolution of the market with emphasis on what has worked well and needs improvement. It also includes a high level overview of market outcomes and basic data for comparison. Market performance that was outside of expected norms was explained. A status report is also presented on the IMO initiatives that have been in place since market opening to improve market performance. The Panel concluded that the electricity market is evolving in a manner that promotes market efficiency and system reliability. Demand for electricity in Ontario continues to increase. More Ontario-based generation was available in 2003 because of the addition of new and restored generation in the province and fewer significant outages. The Panel's reaction to the August 14, 2003 blackout was presented. The Interim report of the Canada-U.S. Power System Outage Task Force has indicated that the blackout was not caused by Ontario electricity markets. No correlation was found between the blackout and the restructuring of the electricity utility industry. Planned or forced outages can have a significant impact on price. Average prices for the off-peak period show an upward trend up to February 2003. 49 refs., 37 tabs., 15 figs

RBMK-1500 accident management for loss of long-term core cooling

International Nuclear Information System (INIS)

Uspuras, E.; Kaliatka, A.

2001-01-01

Results of the Level 1 probabilistic safety assessment of the Ignalina NPP has shown that in topography of the risk, transients dominate above the accidents with LOCAs and failure of the core long-term cooling are the main factors to frequency of the core damage. Previous analyses have shown, that after initial event, as a rule, the reactivity control, as well as short-term and intermediate cooling are provided. However, the acceptance criteria of the long-term cooling are not always carried out. It means that from this point of view the most dangerous accident scenarios are the scenarios related to loss of the core long-term cooling. On the other hand, the transition to the core condition due to loss of the long-term cooling specifies potential opportunities for the management of the accident consequences. Hence, accident management for the mitigation of the accident consequences should be considered and developed. The most likely initiating event, which probably leads to the loss of long term cooling accident, is station blackout. The station blackout is the loss of normal electrical power supply for local needs with an additional failure on start-up of all diesel generators. In the case of loss of electrical power supply MCPs, the circulating pumps of the service water system and MFWPs are switched-off. At the same time, TCV of both turbines are closed. Failure of diesel generators leads to the non-operability of the ECCS long-term cooling subsystem. It means the impossibility to feed MCC by water. The analysis of the station blackout for Ignalina NPP was performed using RELAP5 code. (author)

Radionuclide release calculations for selected severe accident scenarios

International Nuclear Information System (INIS)

Denning, R.S.; Leonard, M.T.; Cybulskis, P.; Lee, K.W.; Kelly, R.F.; Jordan, H.; Schumacher, P.M.; Curtis, L.A.

1990-08-01

This report provides the results of source term calculations that were performed in support of the NUREG-1150 study. ''Severe Accident Risks: An Assessment for Five US Nuclear Power Plants.'' This is the sixth volume of a series of reports. It supplements results presented in the earlier volumes. Analyses were performed for three of the NUREG-1150 plants: Peach Bottom, a Mark I, boiling water reactor; Surry, a subatmospheric containment, pressurized water reactor; and Sequoyah, an ice condenser containment, pressurized water reactor. Complete source term results are presented for the following sequences: short term station blackout with failure of the ADS system in the Peach Bottom plant; station blackout with a pump seal LOCA for the Surry plant; station blackout with a pump seal LOCA in the Sequoyah plant; and a very small break with loss of ECC and spray recirculation in the Sequoyah plant. In addition, some partial analyses were performed which did not require running all of the modules of the Source Term Code Package. A series of MARCH3 analyses were performed for the Surry and Sequoyah plants to evaluate the effects of alternative emergency operating procedures involving primary and secondary depressurization on the progress of the accident. Only thermal-hydraulic results are provided for these analyses. In addition, three accident sequences were analyzed for the Surry plant for accident-induced failure of steam generator tubes. In these analyses, only the transport of radionuclides within the primary system and failed steam generator were examined. The release of radionuclides to the environment is presented for the phase of the accident preceding vessel meltthrough. 17 refs., 176 figs., 113 tabs

Ontario-U.S. power outages : impacts on critical infrastructure

International Nuclear Information System (INIS)

2006-01-01

This paper described the power outage and resulting blackout that occurred on August 14, 2003 and identified how critical infrastructure was directly and interdependently impacted in Canada. The aim of the paper was to assist critical infrastructure protection and emergency management professionals in assessing the potential impacts of large-scale critical infrastructure disruptions. Information for the study was acquired from Canadian and American media reports and cross-sectoral information sharing with provincial and federal governments and the private sector. The blackout impacted most of the sources and means of generating, transmitting and distributing power within the area, which in turn impacted all critical infrastructure sectors. Landline and cellular companies experienced operational difficulties, which meant that emergency responders were impacted. Newspapers and the electronic media struggled to release information to the public. The banking and finance industry experienced an immediate degradation of services. The power outage caused shipping and storage difficulties for commercial retailers and dairy producers. A number of incidents were reported where only partially treated waste water was released into neighbouring waterways. The timing of the blackout coincided with the closures of workplaces and created additional difficulties on transportation networks. Many gas station pumps were inoperable. Police, fire departments and ambulance services experienced a dramatic increase in the volume of calls received, and all branches of the emergency services sector encountered transportation delays and difficulties with communications equipment. Nuclear reactors were also impacted. An estimated 150,000 Government of Canada employees were unable to report to work. Estimates have indicated that the power outage cost Ontario's economy between $1 and $2 billion. The outage negatively impacted 82 per cent of small businesses in Ontario. 170 refs., 3 figs

A Comparison of the Alcohol Use Disorder Identification Test (AUDIT) in General Population Surveys in nine European Countries

DEFF Research Database (Denmark)

Bloomfield, Kim; Knibbe, Ronald; Derickx, Mieke

2006-01-01

was used to analyse intercorrelations between the items. Results: The items ‘blackouts' (men and women) and ‘guilt and remorse' (women) are the most frequently reported consequences. Gender differences tended to be smaller for ‘guilt and remorse' and ‘concern of others', and largest for ‘morning drinking...

Seizure, Fit or Attack? The Use of Diagnostic Labels by Patients with Epileptic or Non-Epileptic Seizures

Science.gov (United States)

Plug, Leendert; Sharrack, Basil; Reuber, Markus

2010-01-01

We present an analysis of the use of diagnostic labels such as "seizure", "attack", "fit", and "blackout" by patients who experience seizures. While previous research on patients' preferences for diagnostic terminology has relied on questionnaires, we assess patients' own preferences and their responses to a doctor's use of different labels…

Smart homes in transition - Investigating the role of households in the development of smart grids in Denmark

DEFF Research Database (Denmark)

Nyborg, Sophie

and black-outs, fuel security, fraud and inaccurate billing. The present PhD project aims to explore the role households play in a sustainable transition of the energy system and takes as its point of departure the Danish smart grid case. Here the smart grid is dominantly framed in relation to the political...

Construction of a low cost wind energy generator; Construcao de um gerador de energia eolica de baixo custo

Energy Technology Data Exchange (ETDEWEB)

Almeida, Jonathan Penha de; Almeida, Silvio Carlos Anibal de [Universidade Federal do Rio de Janeiro (DEM/EP/UFRJ), RJ (Brazil). Escola Politecnica. Dept. de Engenharia Mecanica], Emails: jonathan_penha@poli.ufrj.br, silvioa@gmail.com

2010-07-01

This project presents a low cost wind electric power generator constituted of cheap and easy access materials. The necessary materials are presented for it construction and the expected efficiency, having as reference the city of Fernando de Noronha, Brazil. The elaboration of the generator was initially developed as alternative energy source during blackout.

You're Distracted. This Professor Can Help

Science.gov (United States)

Parry, Marc

2013-01-01

The e-mail drill was one of numerous mind-training exercises in a unique class designed to raise students' awareness about how they use their digital tools. Colleges have experimented with short-term social-media blackouts in the past. But Ms. Hill's course, "Information and Contemplation," goes way further. Participants scrutinize their…

Summary of the Current Status of Lessons Learned From Fukushima Accident

International Nuclear Information System (INIS)

Pasamehmetoglu, Kemal

2013-01-01

This presentation introduced the current status of the lessons learned from the Fukushima accident, and in particular, the recommendations released by a NRC Near-term Task Force to enhance reactor safety in the 21. century. The near-term recommendations are focused on emergency power and emergency cooling availability during station blackout accidents

Boosting the economy with energy efficiency financing

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

From the New Deal to responses to blackouts, history teaches us that crisis times can result in salutary reforms. Recent international economic developments -- namely the international financial and economic crisis, combined with the volatility of energy prices -- threaten to jeopardise our economic well being and our ability to address other goals like climate change mitigation.

A Look Back at the Long Path to Mandating Electric Reliability Standards through the Energy Policy Act of 2005

Energy Technology Data Exchange (ETDEWEB)

Young, Ellen Swyler

2006-07-15

The Act was the culmination of more than eight years of legislative effort in Congress. During this period, the nation saw the Western electricity crisis of 2000-01, the Sept. 11 attacks, the collapse of Enron, the growth of RTOs, and the August 2003 blackout. Each of these influenced the dynamics of the debate. (author)

Risk analysis of NPP in multi-unit site for configuration of AAC power source

International Nuclear Information System (INIS)

Kim, Myung Ki

2000-01-01

Because of the difficulties in finding new sites for nuclear power plants, more units are being added to the existing sites. In these multi-unit sites, appropriate countermeasures should be established to cope with the potential station blackout (SBO) accident. Currently, installation of additional diesel generator (DG) is considered to ensure an alternative AC power source, but it has not been decided yet how many DGs should be installed in a multi-unit site. In this paper, risk informed decision making method, which evaluates reliability of electrical system, core damage frequency, and site average core damage frequency, is introduced to draw up the suitable number of DG in multi-unit site. The analysis results show that installing two DGs lowered the site average core damage frequency by 1.4% compared to one DG in six unit site. In the light of risk-informed decisions in regulatory guide 1.174, there is no difference of safety between two alternatives. It is concluded that one emergency diesel generator sufficiently guarantees safety against station blackout of nuclear power plants in multi-unit site. (author)

Contingency Analysis of Cascading Line Outage Events

Energy Technology Data Exchange (ETDEWEB)

Thomas L Baldwin; Magdy S Tawfik; Miles McQueen

2011-03-01

As the US power systems continue to increase in size and complexity, including the growth of smart grids, larger blackouts due to cascading outages become more likely. Grid congestion is often associated with a cascading collapse leading to a major blackout. Such a collapse is characterized by a self-sustaining sequence of line outages followed by a topology breakup of the network. This paper addresses the implementation and testing of a process for N-k contingency analysis and sequential cascading outage simulation in order to identify potential cascading modes. A modeling approach described in this paper offers a unique capability to identify initiating events that may lead to cascading outages. It predicts the development of cascading events by identifying and visualizing potential cascading tiers. The proposed approach was implemented using a 328-bus simplified SERC power system network. The results of the study indicate that initiating events and possible cascading chains may be identified, ranked and visualized. This approach may be used to improve the reliability of a transmission grid and reduce its vulnerability to cascading outages.

Re-evaluation of Station Blackout in Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Lee, Eunchan; Shin, Taeyoung [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

2014-05-15

This paper proposes a reduction of the uncertainty due to the small number of LOOP events and an estimation of the non-recovery probability after a LOOP event where the operators fail to energize a safety bus using the offsite power recovery during an SBO with recent operating experience. In addition, in this analysis, the CDF is re-evaluated through reflecting the enhancement of the Class-1E battery capacity. For newly constructed KHNP plants, the LOOP frequency and non-recovery probability after a LOOP during an SBO were re-evaluated through integrating the KHNP events into generic data containing broader experiences for PSA. For an initiating event frequency, a new LOOP frequency was calculated through a Bayesian update of the KHNP LOOP frequency using NUREG/CR-6890, which reflects the recent trends and has a large data size. For the non-recovery probability estimation, domestic data were added to the American experiences in the NUREG/CR-6890; these data were fitted to a lognormal distribution in order to reduce the uncertainty due to the small size of the KHNP data. Regarding the battery capacity enhancement, the success criteria during an SBO were re-evaluated considering the longer battery duty time. The CDF was recalculated using the resultant available time for operator action. The changed CDF was reduced by approximately 50% compared with the value before battery improvement. In conclusion, it was quantitatively proven that enlarging the battery capacity to manage SBOs positively affected plant safety. In addition, methods to improve data uncertainty due to the small number of experiences were selected in order to evaluate the LOOP frequency and non-recovery probability after a LOOP for future plants. These efforts contribute to obtaining a realistic risk profile and to prioritizing countermeasures and improvements of vulnerabilities for safety.

47 CFR 76.128 - Application of sports blackout rules.

Science.gov (United States)

2010-10-01

... stations within whose specified zone the community of the community unit or the community within which the... other than major markets as defined in § 76.51, television broadcast stations within whose Grade B... specified zone. [65 FR 68101, Nov. 14, 2000, as amended at 67 FR 68951, Nov. 14, 2002] ...

Non-iterative Voltage Stability

Energy Technology Data Exchange (ETDEWEB)

Makarov, Yuri V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Vyakaranam, Bharat [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hou, Zhangshuan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wu, Di [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meng, Da [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Shaobu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Elbert, Stephen T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Miller, Laurie E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Huang, Zhenyu [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-09-30

This report demonstrates promising capabilities and performance characteristics of the proposed method using several power systems models. The new method will help to develop a new generation of highly efficient tools suitable for real-time parallel implementation. The ultimate benefit obtained will be early detection of system instability and prevention of system blackouts in real time.

Implementation of the Security-Dependability Adaptive Voting Scheme

OpenAIRE

Thomas, Michael Kyle

2011-01-01

As the world moves further into the 21st century, the electricity demand worldwide continues to rapidly grow. The power systems that supply this growing demand continue to be pushed closer to their limits. When those limits are exceeded, system blackouts occur that have massive societal and economical impact. Power system protection relays make up a piece of these limits and can ...

Energy systems security

CERN Document Server

Voeller, John G

2014-01-01

Energy Systems Security features articles from the Wiley Handbook of Science and Technology for Homeland Security covering topics related to electricity transmission grids and their protection, risk assessment of energy systems, analysis of interdependent energy networks. Methods to manage electricity transmission disturbances so as to avoid blackouts are discussed, and self-healing energy system and a nano-enabled power source are presented.

Influence of Plasma Pressure Fluctuation on RF Wave Propagation

International Nuclear Information System (INIS)

Liu Zhiwei; Bao Weimin; Li Xiaoping; Liu Donglin; Zhou Hui

2016-01-01

Pressure fluctuations in the plasma sheath from spacecraft reentry affect radio-frequency (RF) wave propagation. The influence of these fluctuations on wave propagation and wave properties is studied using methods derived by synthesizing the compressible turbulent flow theory, plasma theory, and electromagnetic wave theory. We study these influences on wave propagation at GPS and Ka frequencies during typical reentry by adopting stratified modeling. We analyzed the variations in reflection and transmission properties induced by pressure fluctuations. Our results show that, at the GPS frequency, if the waves are not totally reflected then the pressure fluctuations can remarkably affect reflection, transmission, and absorption properties. In extreme situations, the fluctuations can even cause blackout. At the Ka frequency, the influences are obvious when the waves are not totally transmitted. The influences are more pronounced at the GPS frequency than at the Ka frequency. This suggests that the latter can mitigate blackout by reducing both the reflection and the absorption of waves, as well as the influences of plasma fluctuations on wave propagation. Given that communication links with the reentry vehicles are susceptible to plasma pressure fluctuations, the influences on link budgets should be taken into consideration. (paper)

A study on the implementation effect of accident management strategies on safety

International Nuclear Information System (INIS)

Jae, Moo Sung; Kim, Dong Ha; Jin, Young Ho

1996-01-01

This paper presents a new approach for assessing accident management strategies using containment event trees(CETs) developed during an individual plant examination (IPE) for a reference plant (CE type, 950 MWe PWR). Various accident management strategies to reduce risk have been proposed through IPE. Three strategies for the station blackout sequence are used as an example: 1) reactor cavity flooding only, 2) primary system depressurization only, and 3) doing both. These strategies are assumed to be initiated at about the time of core uncovery. The station blackout (SBO) sequence is selected in this paper since it is identified as one of the most threatening sequences to safety of the reference plant. The effectiveness and adverse effects of each accident management strategy are considered synthetically in the CETs. A best estimate assessment for the developed CETs using data obtained from NUREG-1150, other PRA results, and the MAAP code calculations is performed. The strategies are ranked with respect to minimizing the frequencies of various containment failure modes. The proposed approach is demonstrated to be very flexible in that it can be applied to any kind of accident management strategy for any sequence. 9 refs., 3 figs., 2 tabs. (author)

Curing critical links in oscillator networks as power flow models

International Nuclear Information System (INIS)

Rohden, Martin; Meyer-Ortmanns, Hildegard; Witthaut, Dirk; Timme, Marc

2017-01-01

Modern societies crucially depend on the robust supply with electric energy so that blackouts of power grids can have far reaching consequences. Typically, large scale blackouts take place after a cascade of failures: the failure of a single infrastructure component, such as a critical transmission line, results in several subsequent failures that spread across large parts of the network. Improving the robustness of a network to prevent such secondary failures is thus key for assuring a reliable power supply. In this article we analyze the nonlocal rerouting of power flows after transmission line failures for a simplified AC power grid model and compare different strategies to improve network robustness. We identify critical links in the grid and compute alternative pathways to quantify the grid’s redundant capacity and to find bottlenecks along the pathways. Different strategies are developed and tested to increase transmission capacities to restore stability with respect to transmission line failures. We show that local and nonlocal strategies typically perform alike: one can equally well cure critical links by providing backup capacities locally or by extending the capacities of bottleneck links at remote locations. (paper)

Evaluation of a cavity flooding strategy for the prevention of reactor vessel failure in a severe accident

Energy Technology Data Exchange (ETDEWEB)

Park, Rae Joon; Je, Moo Sung; Park, Chang Kyoo [Korea Atomic Energy Research Institute, TaeJon (Korea, Republic of)

1994-10-01

As a part of the evaluation of accident management strategies for severe accident prevention or mitigation in a station blackout scenario for YGN 3 and 4, an external vessel cooling strategy for the prevention of reactor vessel failure has been estimated using the MAAP4 computer code. The sensitivity studies have been performed such as actuating timings and the number of spray pumps used. To explore external vessel cooling strategies, containment spray pumps were actuated by varying time spanning core uncovery, core melting and relocation of molten core material. It was shown that flooding of the reactor cavity using the containment spray system may prevent reactor vessel failure but may not prevent the failure of the relocation of molten core material during the station blackout sequence of YGN 3 and 4. Reactor vessel failure can be prevented by external vessel cooling using condensed water from the operation of two containment spray pumps at the time of core melting and using water from the operation of one containment spray pumps at the time of core melting and using water from the operation of one containment spray pump at the time of core uncovery. (Author) 46 refs., 26 figs., 5 tabs.

Report on system operation - A background report prepared by the Nordel Operation Committee/OPG in the Nordel project on enhancing efficient functioning of the Nordic electricity market

International Nuclear Information System (INIS)

2004-12-01

This report contains the operation procedures in extreme situations and lessons learned from blackouts, based on a mandate given by the Operations Committee. Nordic TSOs have had common rules and principles for system operation i.e. System Operation Agreement since the late 1990s. The rules have been revised according to the system security and market changes and needs. The collaboration between system operators is regular and fruitful. The knowledge and capability to manage extreme situations of the Nordic power system has continuously increased and the recent blackouts did not show major deficiencies in operation practices. Regardless of the existing good collaboration it is important to continue development in the future in order to ensure high system security. Important development areas are security of reserve supervision and coordination of calculation procedures for transmission limits, enhancement of data exchange routines between control centres in order to improve the overview of the system security within the Nordic power system. More extensive coordination of outage planning processes will further improve the system security. Continuously training of operational staff is important to be able to manage different situations and disturbances efficiently. (BA)

APPROACH TO ASSESSING THE PREPAREDNESS OF HOSPITALS TO POWER OUTAGES

Directory of Open Access Journals (Sweden)

Lenka BREHOVSKÁ

2017-06-01

Full Text Available Within the secondary impacts of electricity blackouts, it is necessary to pay attention to facilities providing medical care for the population, namely the hospitals. Hospitals represent a key position in the provision of health care also in times of crisis. These facilities must provide constant care; it is therefore essential that the preparedness of such facilities is kept at a high level. The basic aim of this article is to analyse the preparedness of hospitals to power outages (power failures, blackouts within a pilot study. On that basis, a SWOT analysis is used to determine strengths and weaknesses of the system of preparedness of hospitals to power outages and solutions for better security of hospitals are defined. The sample investigated consists of four hospitals founded by the Regional Authority (hospitals Nos. 1-4 and one hospital founded by the Ministry of Health of the Czech Republic (hospital No. 5. The results of the study shows that most weaknesses of the preparedness of hospitals are represented by inadequately addressed reserves of fuel for the main backup power supply, poor knowledge of employees who are insufficiently retrained, and old backup power supplies (even 35 years in some cases.

Demand Response Spinning Reserve Demonstration

Energy Technology Data Exchange (ETDEWEB)

Eto, Joseph H.; Nelson-Hoffman, Janine; Torres, Carlos; Hirth,Scott; Yinger, Bob; Kueck, John; Kirby, Brendan; Bernier, Clark; Wright,Roger; Barat, A.; Watson, David S.

2007-05-01

The Demand Response Spinning Reserve project is a pioneeringdemonstration of how existing utility load-management assets can providean important electricity system reliability resource known as spinningreserve. Using aggregated demand-side resources to provide spinningreserve will give grid operators at the California Independent SystemOperator (CAISO) and Southern California Edison (SCE) a powerful, newtool to improve system reliability, prevent rolling blackouts, and lowersystem operating costs.

Energy solutions for sustainable development. Proceedings

DEFF Research Database (Denmark)

production technologies such as fuel cells, hydrogen, bio-energy and wind energy • Centralized energy technologies such as clean coal technologies • Providing renewable energy for the transport sector • Systems aspects, differences between the various major regions throughout the world • End-use technologies......, efficiency improvements and supply links • Security of supply with regard to resources, conflicts, black-outs, natural disasters and terrorism...

Power Outage - 16 October

CERN Multimedia

2014-01-01

At 19:03 last night, a fire in an 18kV circuit breaker in building 212 led to a blackout on the Meyrin site. The CERN fire brigade rapidly brought the fire under control and power was restored by 22:25. Many CERN systems were affected and have been brought back in to service overnight, this work will continue through the day.

Overview of the Nuclear Regulatory Commission's safety research program

International Nuclear Information System (INIS)

Beckjord, E.S.

1989-01-01

Accomplishments during 1988 of the Office of Nuclear Regulatory Research and the program of safety research are highlighted, and plans, expections, and needs of the next year and beyond are discussed. Topics discussed include: ECCS Appendix K Revision; pressurized thermal shock; NUREG-1150, or the PRA method performance document; resolution of station blackout; severe accident integration plan; nuclear safety research review committee; and program management

Supervisory Control and Data Acquisition (SCADA) Security Awareness In a Resource Constrained Learning Environment

Science.gov (United States)

2014-06-16

SCADA systems are connected in some manner to the Global Information Grid ( GIG ), the requirement to educate future computer scientists, software...improves retention and understanding of the learning outcomes [6]. Due to the impact these vulnerabilities can have on the economy , military, and...implications such as what impact a persistent blackout would have on local and national economies . Once a firm understanding of the strategic impacts

The personal and health service impact of falls in 85 year olds: cross-sectional findings from the Newcastle 85+ cohort study.

Directory of Open Access Journals (Sweden)

Joanna Collerton

Full Text Available Falls are common in older people and increase in prevalence with advancing old age. There is limited knowledge about their impact in those aged 85 years and older, the fastest growing age group of the population. We investigated the prevalence and impact of falls, and the overlap between falls, dizziness and blackouts, in a population-based sample of 85 year olds.Cross-sectional analysis of baseline data from Newcastle 85+ Cohort Study.Primary care, North-East England.816 men and women aged 85 years.Structured interview with research nurse. Cost-consequence analysis of fall-related healthcare costs.Over 38% (313/816 of participants had fallen at least once in the previous 12 months and of these: 10.6% (33/312 sustained a fracture, 30.1% (94/312 attended an emergency department, and 12.8% (40/312 were admitted to hospital. Only 37.2% (115/309 of fallers had specifically discussed their falls problem with their general practitioner and only 12.7% (39/308 had seen a falls specialist. The average annual healthcare cost per faller was estimated at £202 (inter-quartile range £174-£231 or US$329 ($284-$377. 'Worry about falling' was experienced by 42.0% (128/305 of fallers, 'loss of confidence' by 40.0% (122/305, and 'going out less often' by 25.9% (79/305; each was significantly more common in women, odds ratios (95% confidence interval for women: men of 2.63 (1.45-4.55, 4.00 (2.27-7.14, and 2.86 (1.54-5.56 respectively. Dizziness and blackouts were reported by 40.0% (318/796 and 6.4% (52/808 of participants respectively. There was marked overlap in the report of falls, dizziness and blackouts.Falls in 85 year olds are very common, associated with considerable psychological and physical morbidity, and have high impact on healthcare services. Wider use of fall prevention services is needed. Significant expansion in acute and preventative services is required in view of the rapid growth in this age group.

Risk energy transition. Ways out of the impasse; Risiko Energiewende. Wege aus der Sackgasse

Energy Technology Data Exchange (ETDEWEB)

Kleinknecht, Konrad [Muenchen Univ., Garching (Germany). Fakultaet fuer Physik

2015-07-01

The exit of the use of nuclear energy in Germany, it was decided in the summer of 2011 in a rush. Now it is becoming obvious that there is no realistic plan for the conversion of energy supply in the envisaged deadline of ten years. For the conversion of our entire power supply and therefore our economy the period is too short. It lacks a robust empirical reason that have to deal with the issues of security of supply, the affordability, the impact on economic development and social justice. Thus, this treansition threatens to fail at their contradictions. Konrad Kleinknecht tries in his book, to name the problems and to find answers. For him, arise the following questions: What are our opportunity to replace with wind and solar power to replace a part of the power supply? What power sources provide secured capacity? Can we dispense with coal-fired plants? Do we need new power lines? How power may be stored? How real is the risk of blackouts in windless nights? Will the power prices continue to rise? Can be avoided the major risks of the energy transition with a fundamental reform of the Renewable Energies Act (EEG)? The power supply must serve the common good and benefit the industrial site Germany. A blackout would be a disaster for the whole country, it must be avoided at all events. How can we manage this, the author present in his evocative book. [German] Der Ausstieg aus der Nutzung der Kernenergie in Deutschland wurde im Sommer 2011 im Eiltempo beschlossen. Jetzt zeigt sich, dass es keinen realistischen Plan fuer den Umbau der Energieversorgung in der vorgesehenen Frist von zehn Jahren gibt. Fuer die Umstellung unserer gesamten Stromversorgung und damit unserer Wirtschaft ist der Zeitraum zu kurz. Es fehlt eine belastbare empirische Begruendung, die Fragen der Versorgungssicherheit, der Finanzierbarkeit, der Auswirkungen auf die wirtschaftliche Entwicklung und die soziale Gerechtigkeit behandeln muesste. Somit droht diese Wende an ihren Widerspruechen zu

The blackout of 2003 and its connection to open access

International Nuclear Information System (INIS)

Delgado, J.

2005-01-01

This white paper discussed the implications of deregulation and policy implementation in the electric power industry, as well recommending changes for greater security and reliability. There have been significant benefits from the introduction of competition in the wholesale electricity market. However, the attempt to reorganize a very complicated industry without ensuring an adequate set of balances between risks and rewards has had mixed results. Reliability problems and threats have not increased as a result of policies, they have increased as a result of the ways in which policies have been implemented. It was suggested that transmission owner-operators are accountable for system security, and have the means to make the system secure in real time. However, North American Electric Reliability Council (NERC), regional councils, Federal Energy Regulatory Commission (FERC) and regional transmission organizations all have a role in system reliability. State regulators and the general public must hold utility owner-operators accountable. It was suggested that there must be a logical and clear allocation of reliability functions among the participants in the electricity network. Costs and responsibilities must be allocated equitably among all participants in and users of the electric system. In addition, sharing and implementation of best practices was recommended, as well as the participation of CEOs in the boards of NERC and in regional reliability councils. It was also suggested that executives in charge of utility operations should be certified to ensure a full awareness of reliability rules. It was recommended that utilities bear responsibility for implementing energy policies at the federal and state levels, including open access and competition. It was concluded that significant transmission construction is needed to support economic development and competitive regional wholesale markets

Innovative safety features of VVER for ensuring high degree of autonomy during beyond design basis accidents

International Nuclear Information System (INIS)

Kumar, Abhay; Mohan, Joe; Kumar, Devesh; Chaudhry, S.M.; Rao, Srinivasa; Gupta, S.K.

2010-01-01

The effectiveness of Passive Heat Removal System (PHRS) in during a station black-out (SBO) accident was assessed by using SCDAP/Relap5. The analysis gave evidence that (i) the Passive Heat Removal System (PHRS) is capable of limiting the consequences of station black out (SBO) and acts as an effective engineered safety system, and (ii) the PHRS intervention prevents core degradation and excessive core heat-up. (P.A.)

Reducing the Vulnerability of Electric Power Grids to Terrorist Attacks

Energy Technology Data Exchange (ETDEWEB)

Ross Baldick; Thekla Boutsika; Jin Hur; Manho Joung; Yin Wu; Minqi Zhong

2009-01-31

This report describes the development of a cascading outage analyzer that, given an initial disturbance on an electric power system, checks for thermal overloads, under-frequency and over-frequency conditions, and under-voltage conditions that would result in removal of elements from the system. The analyzer simulates the successive tripping of elements due to protective actions until a post-event steady state or a system blackout is reached.

Adolescent Alcohol Exposure Persistently Impacts Adult Neurobiology and Behavior

OpenAIRE

Crews, Fulton T.; Vetreno, Ryan P.; Broadwater, Margaret A.; Robinson, Donita L.

2016-01-01

Adolescence is a developmental period when physical and cognitive abilities are optimized, when social skills are consolidated, and when sexuality, adolescent behaviors, and frontal cortical functions mature to adult levels. Adolescents also have unique responses to alcohol compared with adults, being less sensitive to ethanol sedative?motor responses that most likely contribute to binge drinking and blackouts. Population studies find that an early age of drinking onset correlates with increa...

Investigation on accident management measures for VVER-1000 reactors

International Nuclear Information System (INIS)

Tusheva, P.; Schaefer, F.; Rohde, U.; Reinke, N.

2009-01-01

A consequence of a total loss of AC power supply (station blackout) leading to unavailability of major active safety systems which could not perform their safety functions is that the safety criteria ensuring a secure operation of the nuclear power plant would be violated and a consequent core heat-up with possible core degradation would occur. Currently, a study which examines the thermal-hydraulic behaviour of the plant during the early phase of the scenario is being performed. This paper focuses on the possibilities for delay or mitigation of the accident sequence to progress into a severe one by applying Accident Management Measures (AMM). The strategy 'Primary circuit depressurization' as a basic strategy, which is realized in the management of severe accidents is being investigated. By reducing the load over the vessel under severe accident conditions, prerequisites for maintaining the integrity of the primary circuit are being created. The time-margins for operators' intervention as key issues are being also assessed. The task is accomplished by applying the GRS thermal-hydraulic system code ATHLET. In addition, a comparative analysis of the accident progression for a station blackout event for both a reference German PWR and a reference VVER-1000, taking into account the plant specifics, is being performed. (authors)

Delivering a secure electricity supply on a low carbon pathway

International Nuclear Information System (INIS)

Boston, Andy

2013-01-01

The energy system can only be considered sustainable in the long term if it is low carbon, affordable and secure. These three create a complex trilemma for all stakeholders in the energy business who have to strike a careful balance without neglecting any one aspect. This discussion paper examines the issues surrounding security of supply of the power system which has received less attention than the other aspects. It looks at how threats and mitigation measures can be classified in terms of where they act on the supply chain and the timescale over which they act. Only by considering the full range of timescales from seconds to decades can the full picture emerge of the effects of new technologies on security of supply. An examination of blackouts over the past 40 years sheds light on the causes of failure to supply and the most vulnerable aspects of the supply chain. - Highlights: ► Energy systems are only sustainable if they are low carbon, affordable and secure. ► Threats to security can be classified by timescale and position in the supply chain. ► The impact of new technologies on security must be considered across all timescales. ► Recent blackouts show the network is most vulnerable and weather the leading cause

Cycle 22

International Nuclear Information System (INIS)

Kappernman, J.G.; Albertson, V.D.

1991-01-01

This paper reports that for many electric utility systems, Solar Cycle 22 has been the first introduction to the phenomena of Geomagnetic Disturbances and the disrupting and damaging effects that they can have upon modern power systems. For all intents and purposes, Power Industry awareness of Cycle 22 started with a bang during the Great Geomagnetic Storm of March 13, 1989. This storm caused a blackout to the entire Province of Quebec, permanently damaged a large nuclear plant GSU transformer in New Jersey, and created enough havoc across the entire North American power grid to create the plausible threat of a massive power system blackout. The flurry of activity and investigation that followed has led many engineers to realize that their power systems are indeed vulnerable to this phenomena and if anything are becoming ever more vulnerable as the system grows to meet future requirements. As a result some organizations such as Hydro Quebec, PSE and G, and the PJM Pool now implement strategic measures as a remedial response to detection of geomagnetic storm conditions. Many more companies pay particularly close attention to storm forecasts and alerts, and the industry in general has accelerated research and monitoring activities through their own means of in concert with the Electric Power Research Institute (EPRI)

Model of nuclear reactor type VVER-1000/V-320 built by computer code ATHLET-CD

International Nuclear Information System (INIS)

Georgiev, Yoto; Filipov, Kalin; Velev, Vladimir

2014-01-01

A model of nuclear reactor type VVER-1000 V-320 developed for computer code ATHLET-CD2.1A is presented. Validation of the has been made, in the analysis of the station blackout scenario with LOCA on fourth cold leg is shown. As the calculation has been completed, the results are checked through comparison with the results from the computer codes ATHLET-2.1A, ASTEC-2.1 and RELAP5mod3.2

Computer simulation of black out followed by multiple failures in PWR type nuclear power plants

International Nuclear Information System (INIS)

Silva Filho, E.

1989-01-01

The computer code RELAP 5/MOD 1 has been utilized to investigate the thermal-hydraulic behaviour of a standard 1300 MWe pressurized water reactor plant of the KWU design during a station blackout following a inadequate performance of the pressurizer and steam generator safety valves. During the simulation the reactor scram system the emergency coolant system of the primary loop and the emergency Feedwater system of the secondary loop are considered inactive. (author) [pt

Heat wave generates questions about Ontario's generation capacity

International Nuclear Information System (INIS)

Horne, D.

2005-01-01

Concerns regarding Ontario's power generation capacity were raised following a major blackout which occurred in August 2003. Power demand reached 26,170 MW during the weeks leading to the blackout, forcing the Independent Electricity System Operator (IESO) to ask residents to reduce electricity use during the day. The grid operator had also issued a forecast that Toronto could face rolling blackouts during times of heavy power demand. Ontario power consumption records were set in June and July of 2003 due to a heat wave, with hourly demand exceeding 25,000 MW on 53 occasions. Ontario was forced to import up to 3,400 MW (13 per cent of its power needs) from neighbouring provinces and the United States. During that period, the price of power had risen sharply to over 30 cents a kilowatt hour, although household consumers were still charged in the 5 to 10 cent range per kilowatt hour. However, it was noted that taxpayers will eventually bear the cost of importing power. The IESO noted that importing electricity is cheaper than the generation available in Ontario and that it is more economical to import, based on the market clearing price of all generators. In 2004, the IESO purchased 6 per cent of their electricity from the United States. That figure is expected to increase for 2005. Ontario generators produced 26.9 million MWh more in the summer of 2005 than during the same period in 2004 to meet electricity demand levels. It was noted that although importing power presently meets peak demand, the IESO agrees there is a need for new generation within Ontario. In addition to restarting Ontario's Pickering and Bruce nuclear facilities, more than 3,300 MW of new gas-fired generation is under construction or approved, and more than 9,000 MW are in various stages of approval. This paper discussed the effect of high energy costs on industry and Ontario's ability to meet future electricity demand in comparison to neighbouring jurisdictions. Issues regarding grid maintenance

Schemes for protecting electric power systems; Esquemas de protecao de sistemas de energia eletrica

Energy Technology Data Exchange (ETDEWEB)

Almeida, Paulo Cesar de

2002-07-01

The objective of this dissertation is to accomplish an introduction to the studies and the applications of the System Protection Schemes (SPS) used to maintain the electric power systems safety. A small group of definitions and concepts from the 'protection, reliability and power systems performance analysis' areas is presented with the objective of distinguishing SPS from the conventional system component protections. It also helps in understanding the functions of the SPS with more clarity. The SPS are used to maintain the integrity of the system when it is submitted to phenomena that provoke instability or cascade circuit outages. The classification and the description of these phenomena, as well as the SPS application are shown in this dissertation. The general structure of the SPS, the ways of classifying them and the different actions used by SPS to control the disturbances are the objectives of the analysis of this work. In order to exemplify, a vision is given of how the SPS are located in the Brazilian interconnected system (BIS) and also in the rest of the world. Some SPS used in Brazil deserved special attention. The analyses of the main blackouts that occurred in Brazil and in North America are presented, in a summarized term, in appendix I. Considerable knowledge is obtained from these analyses, leading to implementation measures that minimize the risk of interruptions in the energy supply. A comparison is also made of the degree of severity of the great blackouts that happened in Brazil and, for the two largest, an estimate of their respective interruption costs is made. In appendix II, an attempt was also made to establish the basic requirements for the SPS implementation using micro processing technology. Based on the experience lived during the studies developed by the group that analyzed the safety of the Bis after the blackout on March 11/1999, criteria and procedures to analyze the safety of the system and to accomplish studies of SPS

POWER STABILITY MONITORING BASED ON VOLTAGE INSTABILITY PREDICTION APPROACH THROUGH WIDE AREA SYSTEM

OpenAIRE

H. H. Goh; Q. S. Chua; S. W. Lee; B. C. Kok; K. C. Goh; K. T.K. Teo

2014-01-01

Nowadays, power systems are being forced to operate closer to its security limit due to current economic growth and the difficulties to upgrade the existing grid infrastructure. With the sudden increment of power demand, voltage instability problem has become a main concern to the power system operator because voltage instability has led or crucially contributed to some major blackouts throughout the world. Hence, methods for early warning and early prevention are required to prevent the powe...

Network Design for Reliability and Resilience to Attack

Science.gov (United States)

2014-03-01

Program MNE Montenegro PPS-m-n Path-Portfolio-Selection problem where the defender can select a set of m paths and the attacker can destroy n arcs in...where power plants are represented by nodes. Such a node could fail, causing a chain reaction and blackout. An example for a network with arc...deliberate and un- intentional failures. An unintentional failure is a random failure that just happens, e.g., a power plant goes down because of age. A

Understanding the response of commercial and institutional organizations to the California energy crisis. A report to the California Energy Commission - Sylvia Bender, Project Manager

OpenAIRE

Lutzenhiser, Loren; Janda, Kathryn; Kunkle, Rick; Payne, Christopher

2002-01-01

Beginning in the summer of 2000, California experienced serious energy supply problems, sharp increases in wholesale (and retail) electricity and natural gas prices, and isolated blackouts. In response to the rapidly worsening electricity situation in California in late 2000, the state set, as an initial goal, the reduction of the state's peak demand for the summer of 2001 by 5,000 megawatts. To meet this goal, the governor and legislature took a variety of steps to enhance supply, enco...

Intelligent Commercial Lighting: Demand-Responsive Conditioning and Increased User Satisfaction

OpenAIRE

Agogino, Alice M.

2005-01-01

Energy efficiency has recently come to the forefront of energy debates, especially in the state of California. This focus on efficiency has been driven by the deregulation of electrical-energy distribution, the increasing price of electricity, and the implementation of rolling blackouts. Currently, buildings consume over 1/3 of primary energy, and 2/3 of all electricity produced in the U.S. Commercial buildings consume roughly half of this, and lighting is responsible for approximately 40% of...

MELCOR DB Construction for the Severe Accident Analysis DB

International Nuclear Information System (INIS)

Song, Y. M.; Ahn, K. I.

2011-01-01

The Korea Atomic Energy Research Institute (KAERI) has been constructing a severe accident analysis database (DB) under a National Nuclear R and D Program. In particular, an MAAP (commercial code being widely used in industries for integrated severe accident analysis) DB for many scenarios including a station blackout (SBO) has been completed. This paper shows the MELCOR DB construction process with examples of SBO scenarios, and the results will be used for a comparison with the MAAP DB

The Potential for Wind Energy Meeting Electricity Needs on Vancouver Island

OpenAIRE

Ryan Prescott; G. Cornelis van Kooten; Hui Zhu

2006-01-01

In this paper, an in-depth analysis of power supply and demand on Vancouver Island is used to provide information about the optimal allocation of power across ‘generating’ sources and to investigate the economics of wind generation and penetrability into the Island grid. The methodology developed can be extended to a region much larger than Vancouver Island. Results from the model indicate that Vancouver Island could experience blackouts in the near future unless greater name-plate capacity i...

Angle Control-Based Multi-Terminal Out-of-Step Protection System

OpenAIRE

Antans Sauhats; Andrejs Utans; Dmitrijs Antonovs; Andrejs Svalovs

2017-01-01

From time to time a sequence of unexpected and overlapping contingencies may lead to power system angular instability and even blackouts if not addressed adequately by means of an out-of-step (OOS) protection system. The motivation of the paper is an attempt to develop a workable prototype of the OOS protection system. The deficiencies of the protection currently used in the Latvian Power System network are highlighted and a new protection structure is proposed. The protection system comprise...

Digitalized distribution system for the power supply. Internet of the energy; Digitalisiertes Verteilungsnetz fuer die Stromversorgung. Internet der Energie

Energy Technology Data Exchange (ETDEWEB)

Reifenhaeuser, Bernd; Ebbes, Alexander [GIP AG, Mainz (Germany)

2013-05-13

Current power distribution systems are highly connected with each other, redundantly designed with respect to the security of supply and require a central planning. Due to the close interlocking, disturbances may spread quickly and lead to a large-scale blackout. In order to counteract failures in the face of an increasing share of renewable energy, energy has to be hold out - an inefficient and expensive reserve. A decentralized, digital power distribution system may handle the task much better.

Drinking motives moderate the impact of pre-drinking on heavy drinking on a given evening and related adverse consequences-an event-level study

OpenAIRE

Kuntsche Emmanuel; Labhart Florian

2013-01-01

Aims: To test whether (i) drinking motives predict the frequency of pre drinking (i.e. alcohol consumption before going out); (ii) drinking motives predict HDGE (heavy drinking on a given evening: 4+ for women 5+ for men) and related adverse consequences (hangover injuries blackouts etc.) even when pre drinking is accounted for and (iii) drinking motives moderate the impact of pre drinking on HDGE and consequences. Design: Using the internet based cellphone optimized assessment technique (ICA...

Essence and characteristics of the Westinghouse technology AP1000

International Nuclear Information System (INIS)

Llovet, Ricardo

2014-01-01

The AP1000 nuclear power plant can place the reactor in a Safe Shutdown Condition within the first 72 hours of a Station Blackout, without the use of AC power or operator action •With some operator action after 3 days, the AP1000 nuclear power plant continues to maintain reactor core cooling and Spent Fuel Pool cooling indefinitely •The AP1000 nuclear power plant has superior coping capabilities as well as significantly reduced risk for core damage

Main results of assessing integrity of RNPP-3 steam generator heat exchange tubes in accident management

International Nuclear Information System (INIS)

Shugajlo, Al-j P.; Mustafin, M.A.; Shugajlo, Al-r P.; Ryzhov, D.I.; Zhabin, O.I.

2017-01-01

Tubes integrity evaluation under accident conditions considering drain of SG and current technical state of steam exchange tubes is an important question regarding SG long-term operation and improvement of accident management strategy.The main investigation results prepared for heat exchange surface of RNPP-3 steam generator are presented in this research aimed at assessing integrity of heat exchange tubes under accident conditions, which lead to full or partial drain of heat exchange surface, in particular during station blackout.

Tests of Shaft Seal Systems of Circulation Pumps during Station Blackout

Energy Technology Data Exchange (ETDEWEB)

Beisiegel, A.; Foppe, F.; Wich, M.

2014-07-01

AREVA GmbH operates a unique Thermal-hydraulic plat form in Germany, France and USA. It is recognised as a test body according to ISO 17025. The Deutsche Akkreditierungsstelle GmbH (DAkkS - German Society for Accreditation) has also certified the Thermal-hydraulic platform as an independent inspection body Type C according to ISO 17020. A part of this platform is the Component Laboratory located in Karlstein, Germany which is in operation since more than 50 years. The testing activities cover a wide range as: Critical Heat Flux Tests, Valve Testing and Environmental Qualification for safety related components. Since 2011 the Component Qualification Karlstein extended their testing scope for different types of Shaft Seal Systems. (Author)

Blackouts to Lifelong Memories: Digital Storytelling and the College Alcohol Habitus

Science.gov (United States)

Burnett, Audrey J.; Walter, Katherine Ott; Baller, Stephanie L.

2016-01-01

Digital stories (N = 71) were created in partial fulfillment of undergraduate coursework at a large mid-Atlantic university. Based on the alcohol habitus, two major themes emerged: the content present (e.g., dissonance between visual and narrative representations) and the content conspicuously absent from the stories (e.g., first-person…

MANAGING A PROLONGED STATION BLACKOUT CONDITION IN AHWR BY PASSIVE MEANS

Directory of Open Access Journals (Sweden)

MUKESH KUMAR

2013-10-01

In view of this, an analysis has been performed for decay heat removal characteristics over several days of an AHWR by ICs. The computer code RELAP5/MOD3.2 was used for this purpose. Results indicate that the ICs can remove the decay heat for more than 10 days without causing any bulk boiling in the GDWP. After that, decay heat can be removed for more than 40 days by boiling off the pool inventory. The pressure inside the containment does not exceed the design pressure even after 10 days by condensation of steam generated from the GDWP on the walls of containment and on the Passive Containment Cooling System (PCCS tubes. If venting is carried out after this period, the decay heat can be removed for more than 50 days without exceeding the design limits.

Human reliability analysis for venting a BWR Mark I during a severe accident

International Nuclear Information System (INIS)

Nelson, W.R.; Blackman, H.S.

1986-01-01

A Human Reliability Analysis (HRA) was performed for the operator actions necessary to achieve containment venting for the Peach Bottom Atomic Power Station. This study was funded by the United States Nuclear Regulatory Commission (USNRC) and performed by the Idaho National Engineering Laboratory (INEL). The goal of the analysis was to estimate Human Error Probabilities (HEPs) to determine the likelihood that operators would fail to complete the venting process. The analysis was performed for two generic accident sequences: anticipated transient without scram (ATWS) and station blackout. Two major methods were used to estimate the HEPs: Technique for Human Error rate Prediction (THERP) and Success Likelihood Index Methodology (SLIM). For the ATWS scenarios analyzed, the calculated HEPs ranged from 0.23 to 0.35, depending on the number of vent paths that are required to reduce the containment pressure. It should be noted that the confidence bounds around these HEPs are large, However, even when considering the large confidence range, the failure probabilities are larger than what is typical for normal operator actions. For station blackout, the HEP is 1.0, resulting from the dangerous environmental conditions that are present, assuming that plant management would not deliberately expose personnel to a potentially fatal environment. These results are based on the analysis of draft procedures for containment venting. It is probable that careful revision of the procedures could reduce the human error probabilities

Control area readiness audit report of the Independent Electricity Market Operator (IMO)

International Nuclear Information System (INIS)

Gladish, L.A.; Campoli, G.; Le, Q.; Farrokhpay, S.; Kirby, B.; Penwell, C.; Weaver, S.; Vicini, D.; Wells, M.

2004-01-01

The Independent Electricity Market Operator (IMO) is a control area authority that is responsible for the safe and reliable operation of its portion of the bulk electric system in cooperation with neighbouring control areas. This audit by the North American Electric Reliability Council (NERC) reviewed the readiness of Ontario's IMO to meets its responsibilities as a control area operator. NERC recommended specific actions to correct the deficiencies that resulted in the blackout in southeastern Ontario and northeastern United States on August 14, 2003. Initiatives to strengthen compliance with existing standards were also suggested along with longer-term technical initiatives to prevent or mitigate the impacts of cascading blackouts in the future. The audit process included: a self-assessment questionnaire to the control area being audited; a questionnaire to neighbouring control areas; a questionnaire to the reliability coordinator and an on-site audit by a selected audit team. The following issues were reviewed: criteria and compliance, authority, responsibilities in the planning time frame, real time monitoring, system restoration, delegation of reliability coordinator functions, outage coordination, transmission and generation relaying, energy emergency plan, operating policy, line clearances, and nuclear power plant requirements. It was concluded that the IMO has the necessary plans, procedures, processes, tools and trained personnel to respond to emergency events. The audit did not find any major operational problems, but offered a few recommendations for improvement. tabs

Application of computational intelligence techniques for load shedding in power systems: A review

International Nuclear Information System (INIS)

Laghari, J.A.; Mokhlis, H.; Bakar, A.H.A.; Mohamad, Hasmaini

2013-01-01

Highlights: • The power system blackout history of last two decades is presented. • Conventional load shedding techniques, their types and limitations are presented. • Applications of intelligent techniques in load shedding are presented. • Intelligent techniques include ANN, fuzzy logic, ANFIS, genetic algorithm and PSO. • The discussion and comparison between these techniques are provided. - Abstract: Recent blackouts around the world question the reliability of conventional and adaptive load shedding techniques in avoiding such power outages. To address this issue, reliable techniques are required to provide fast and accurate load shedding to prevent collapse in the power system. Computational intelligence techniques, due to their robustness and flexibility in dealing with complex non-linear systems, could be an option in addressing this problem. Computational intelligence includes techniques like artificial neural networks, genetic algorithms, fuzzy logic control, adaptive neuro-fuzzy inference system, and particle swarm optimization. Research in these techniques is being undertaken in order to discover means for more efficient and reliable load shedding. This paper provides an overview of these techniques as applied to load shedding in a power system. This paper also compares the advantages of computational intelligence techniques over conventional load shedding techniques. Finally, this paper discusses the limitation of computational intelligence techniques, which restricts their usage in load shedding in real time

Quantification of uncertainties in source term estimates for a BWR with Mark I containment

International Nuclear Information System (INIS)

Khatib-Rahbar, M.; Cazzoli, E.; Davis, R.; Ishigami, T.; Lee, M.; Nourbakhsh, H.; Schmidt, E.; Unwin, S.

1988-01-01

A methodology for quantification and uncertainty analysis of source terms for severe accident in light water reactors (QUASAR) has been developed. The objectives of the QUASAR program are (1) to develop a framework for performing an uncertainty evaluation of the input parameters of the phenomenological models used in the Source Term Code Package (STCP), and (2) to quantify the uncertainties in certain phenomenological aspects of source terms (that are not modeled by STCP) using state-of-the-art methods. The QUASAR methodology consists of (1) screening sensitivity analysis, where the most sensitive input variables are selected for detailed uncertainty analysis, (2) uncertainty analysis, where probability density functions (PDFs) are established for the parameters identified by the screening stage and propagated through the codes to obtain PDFs for the outputs (i.e., release fractions to the environment), and (3) distribution sensitivity analysis, which is performed to determine the sensitivity of the output PDFs to the input PDFs. In this paper attention is limited to a single accident progression sequence, namely; a station blackout accident in a BWR with a Mark I containment buildings. Identified as an important accident in the draft NUREG-1150 a station blackout involves loss of both off-site power and DC power resulting in failure of the diesels to start and in the unavailability of the high pressure injection and core isolation coding systems

Integration of electric vehicles with optimum sized storage for grid connected photo-voltaic system

OpenAIRE

Sulabh Sachan

2017-01-01

The necessity of energy storage by means of battery/EV is exceedingly expected in event of energy blackouts. Different advantages incorporate sparing the cash in purchasing top time power and support the grid when grid power is deficit against the load demand. In this paper, ideal size of energy storage in a grid associated photovoltaic (PV) framework is proposed. The methodology of energy flow choice is produced with the appraisal on accessibility of PV yield control and the load demand. The...

Power and performance. Y2K challenges for electricity grids in Eastern Europe

International Nuclear Information System (INIS)

Kossilov, A.; Gueorguiev, B.; Ianev, I.; Purvis, E.

1999-01-01

The Year 2000 problem can directly affect the safety of nuclear power plants through interfaces with electric power and telecommunication systems. Recently, probabilistic safety assessments have made it clear that a 'station blackout' at a nuclear power plant is a major contributor to the sequence of events that could cause severe accidents. Within the IAEA actions concerned with Y2K problem, particular focus was on countries in eastern Europe, where here were delays in taking Y2K corrective actions

Restructuring Electricity Markets when Demand is Uncertain

DEFF Research Database (Denmark)

Boom, Anette; Buehler, Stefan

2006-01-01

We examine the effects of reorganizing electricity markets on capacity investments, retail prices and welfare when demand is uncertain. We study the following market configurations: (i) integrated monopoly, (ii) integrated duopoly with wholesale trade, and (iii) separated duopoly with wholesale...... trade. Assuming that wholesale prices can react to changes in retail prices (but not vice versa), we find that generators install sufficient capacity to serve retail demand in each market configuration, thus avoiding blackouts. Furthermore, aggregate capacity levels and retail prices...

New Orleans may go municipal

International Nuclear Information System (INIS)

Woehrle, L.A.

1985-01-01

Recent moves by the New Orleans City Council to consolidate two investor-owned utilities operating under franchise agreements into a publicly owned utility could make the 179,000-user utility the nation's 12th ranking public power system. Voters have changed their minds on the advantages of local control because of costly blackouts. At the root of the effort are economic concerns and some unpaid IOUs owed by the franchise companies because of nuclear plant construction. A task force recommended a municipal buyout

Smart Grid Security: Threats, Challenges, and Solutions

OpenAIRE

Sanjab, Anibal; Saad, Walid; Guvenc, Ismail; Sarwat, Arif; Biswas, Saroj

2016-01-01

The cyber-physical nature of the smart grid has rendered it vulnerable to a multitude of attacks that can occur at its communication, networking, and physical entry points. Such cyber-physical attacks can have detrimental effects on the operation of the grid as exemplified by the recent attack which caused a blackout of the Ukranian power grid. Thus, to properly secure the smart grid, it is of utmost importance to: a) understand its underlying vulnerabilities and associated threats, b) quanti...

Solar storms; Tormentas solares

Energy Technology Data Exchange (ETDEWEB)

Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

2016-08-01

Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

Asset Pricing in Markets with Illiquid Assets

OpenAIRE

Longstaff, Francis A

2005-01-01

Many important classes of assets are illiquid in the sense that they cannot always be traded immediately. Thus, a portfolio position in these types of illiquid investments becomes at least temporarily irreversible. We study the asset-pricing implications of illiquidity in a two-asset exchange economy with heterogeneous agents. In this market, one asset is always liquid. The other asset can be traded initially, but then not again until after a “blackout†period. Illiquidity has a dramatic e...

Measurement of Exhaust Emissions from Diesel-Powered Forklifts during Operations in Ammunition Storage Magazines.

Science.gov (United States)

1984-05-01

to CO over a work period can cause central nervous system depression , blackouts, coma, and eventual death at the concentrations that could be reached...Camel, Jr., Eds., National Cancer Institute Monograph No. 9, p. 225, 1962. 11.6 Sawicki, E., R. C. Corey, A. E. Dooley,J. B. Gisclard, J. L. Monkman, R...tum wmammmmm ~m mamas aB-mm7 B-27 1K PEDCO INVIRONMENTAL. INC ARMY DIESEL FORKLIFT STUDY Location THREE TOt Description TEST SI Date: DECEMIER 6. 1103

MELRPI - development and use

International Nuclear Information System (INIS)

Sozer, A.

1985-01-01

The MELRPI computer code has been developed by Rensselaer Polytechnic Institute under the sponsorship of Oak Ridge National Laboratory (ORNL) and, more recently, the Empire State Electrical Energy Research Corporation (ESEERCO). The code was developed especially for severe accident analyses concerning BWRs and is not applicable to PWRs. MELRPI.MOD2, one of the ORNL-severe accident analysis codes, has been applied for the first time to station blackout transient analysis for the Browns Ferry nuclear power plant in order to estimate the progression of core degradation

Calculation of spent fuel pool severe accident with MELCOR

International Nuclear Information System (INIS)

Deng Jian; Xiang Qing'an; Zhou Kefeng

2014-01-01

A calculation model was established for spent fuel pool (SFP) using MELCOR code to study the severe accident phenomena caused by the long term station black-out (SBO), including spent fuel heatup, zirconium cladding oxidation, and the injection into SFP to mitigate the severe accident. The results show that the severe accident progression is slow and relates directly with the initial water level in SFP. It is illustrated that the injection into SFP is one of the best mitigated measures for the SFP severe accident. (authors)

Severe accident sequences simulated at the Grand Gulf Nuclear Station

International Nuclear Information System (INIS)

Carbajo, J.J.

1999-01-01

Different severe accident sequences employing the MELCOR code, version 1.8.4 QK, have been simulated at the Grand Gulf Nuclear Station (Grand Gulf). The postulated severe accidents simulated are two low-pressure, short-term, station blackouts; two unmitigated small-break (SB) loss-of-coolant accidents (LOCAs) (SBLOCAs); and one unmitigated large LOCA (LLOCA). The purpose of this study was to calculate best-estimate timings of events and source terms for a wide range of severe accidents and to compare the plant response to these accidents

Battery Electric Vehicles can reduce greenhouse has emissions and make renewable energy cheaper in India

Energy Technology Data Exchange (ETDEWEB)

Gopal, Anand R [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Witt, Maggie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sheppard, Colin [Humboldt State Univ., Arcata, CA (United States); Harris, Andrew [Humboldt State Univ., Arcata, CA (United States)

2015-07-01

India's National Mission on Electric Mobility (NMEM) sets a countrywide goal of deploying 6 to 7 million hybrid and electric vehicles (EVs) by 2020. There are widespread concerns, both within and outside the government, that the Indian grid is not equipped to accommodate additional power demand from battery electric vehicles (BEVs). Such concerns are justified on the grounds of India's notorious power sector problems pertaining to grid instability and chronic blackouts. Studies have claimed that deploying BEVs in India will only

The modeling and analysis of in-vessel corium/structure interaction in boiling water reactors

International Nuclear Information System (INIS)

Podowski, M.Z.; Kurul, N.; Kim, S.-W.; Baltyn, W.; Frid, W.

1997-01-01

A complete stand-alone state-of-the-art model has been developed of the interaction between corium debris in the lower plenum and the RPV walls and internal structures, including the vessel failure mechanisms. This new model has been formulated as a set of consistent computer modules which could be linked with other existing models and/or computer codes. The combined lower head and lower plenum modules were parametrically tested and applied to predict the consequences of a hypothetical station blackout in a Swedish BWR. (author)

Simulation of accident and restrained transients in PWR nuclear power plant with RELAP 5/MOD 1 computer code

International Nuclear Information System (INIS)

Silva Filho, E.

1986-01-01

The computer code RELAP5/MOD1 has been utilized to investigate the thermal-hydraulic behaviour of a standard 1300 Mwe pressurized water reactor plant of the KWU design during a station blackout and during a loss-of-coolant accident involving 2% break in the cross-sectional area the cold leg in one of the four loops and located between the pump and the reactor pressure vessel. During the simulations the reactor scram system and the emergency coolant system were considered inactive. (Author) [pt

IAEA Completes Expert Mission to Kori 1 Nuclear Power Plant in the Republic of Korea

International Nuclear Information System (INIS)

2012-01-01

Full text: An international team of nuclear safety experts led by the International Atomic Energy Agency (IAEA) has completed a review of safety practices at the Kori 1 Nuclear Power Plant (NPP) near Busan in the Republic of Korea. The IAEA assembled the team at the request of Korea Hydro and Nuclear Power Co., Ltd. (KHNP) following a station blackout event on 9 February 2012. The team - comprised of experts from Belgium, France, Sweden, United Kingdom and the IAEA - conducted its mission from 4 to 11 June 2012 under the leadership of the IAEA's Division of Nuclear Installation Safety. The expert mission applied the methodology of the IAEA's Operational Safety Review (OSART) missions and covered the areas of Management, Organization and Administration; Operations; Maintenance and Operating Experience. The conclusions of the review are based on the IAEA's Safety Standards, which are developed by the Agency to help nations improve their nuclear safety practices, which are the responsibility of every nation that undertakes nuclear-related activities. Throughout the review, the exchange of information between the experts and plant personnel was very open, professional and productive. Prior to the mission, Korea's Nuclear Safety and Security Commission completed an interim investigation, and it continues to perform additional investigations and technical reviews. The Commission identified corrective actions for the plant concerning reinforcing safety culture, emergency diesel generator reliability, configuration control and risk management during refueling outage, test and maintenance procedures and emergency action level declaration. The expert mission confirmed that some corrective actions have already been completed and others are in progress. The expert mission found the management and staff of Kori 1 NPP to be committed and working hard to complete all improvements. The root cause analysis of the event at Kori 1 NPP is still in progress and is expected to lead to

Anticipating Interruptions. Security and risk in a liberalized electricity infrastructure

Energy Technology Data Exchange (ETDEWEB)

Silvast, A.

2013-11-01

During the past ten years, a number of social scientists have emphasized the importance of material infrastructures like electricity supply as a research topic for the social sciences. The developing of such new perspectives concerning infrastructures also includes uncertainties and risks. This research analyzes the management of uncertainties in the Finnish electricity infrastructure by posing the following research question: how are electricity interruptions, or blackouts, anticipated in Finland and how are these interruptions managed as risks? The main research methodology of the work is multi-sited field work. The empirical materials include interviews with experts and lay people (33 interviews); participant observation in two electricity control rooms; an electricity consumer survey (115 respondents); and also a number of infrastructure and security policy documents and observations from electricity security seminars. The materials were primarily gathered between 2004 and 2008. Social science research often links risks with major current social changes or socio-cultural risk perceptions. In recent international social science discussions, however, a new research topic has emerged - those styles of reasoning and techniques of governance that are deployed to manage risk as a practical matter. My study explores these themes empirically by focusing on the specific habitual practices of risk management in the Finnish electricity infrastructure. The work develops various also semi-ethnographic inquiries into infrastructure risk techniques like monitor screening of real-time risks in electricity control rooms; the management of risks in a liberalized electricity market; the emergence of Finnish reasoning about blackouts from a specific historical background; and the ways in which electricity consumers respond to blackouts in their homes. In addition, the work reflects upon the position of a risk researcher in those situations when the research subjects do not define

What do customers want from improved residential electricity services? Evidence from a choice experiment

International Nuclear Information System (INIS)

Huh, Sung-Yoon; Woo, JongRoul; Lim, Sesil; Lee, Yong-Gil; Kim, Chang Seob

2015-01-01

Improvements in customer satisfaction as well as product/service quality represent a common objective of all businesses, and electricity services are no exception. Using choice experiments and a mixed logit model, this study quantitatively analyzes customers' preferences and their marginal willingness to pay for improved residential electricity services. The study provides an ex ante evaluation of customers' acceptance of hypothetical electricity services. According to the results, customers consider the electricity bill and the electricity mix as the two most important attributes when choosing their electricity services. Customers are willing to pay 2.2% more in the average electricity bill (an additional monthly electricity bill of KRW 1,064; USD 0.96) for a significant increase in the share of renewable energy, which is far less than the actual cost of achieving this renewable target. Therefore, it is better to maintain the current electricity mix in principle, and the renewable share should be gradually expanded instead of making a sudden change in the electricity mix. In addition, customers are willing to pay KRW 6,793 (USD 6.15) more to reduce blackouts once in a year and KRW 64/year (USD 0.06/year) to reduce a minute of each blackout. -- Highlights: •Customers' preferences for improved residential electricity services are analyzed. •Empirical setting is a sample of residents in South Korea. •The electricity bills and electricity mix are important to customers. •Increase in electricity bill of different electricity mix is considered

A study on the characteristics, predictions and policies of China’s eight main power grids

International Nuclear Information System (INIS)

Wang, Jianzhou; Dong, Yao; Jiang, He

2014-01-01

Highlights: • Indian blackout is analyzed as a warning for China’s power system. • Issues and recommendations of China’s eight power grids are presented. • Five models are employed for scenario analysis on power generation and consumption. • The optimized combined model outperforms other models. • Methods towards balancing power generation and environmental impacts are proposed. - Abstract: Electricity is an indispensable energy source for modern social and economic development. However, large-scale blackouts can cause incalculable loss to society. In 2012, three major Indian power grids collapsed, resulting in the interruption of the electricity supply to over 600 million people. To avoid an event like that, China needs to forecast the power generation and consumption of eight power grids effectively. This paper first analyzes the characteristics of eight power grids and then proposes a combined model based on three improved grey models optimized by a differential evolution algorithm to predict electricity production and consumption of each power grid. The optimized combined forecasting model provides a better prediction than other models, and it is also the most workable and satisfactory model. Experiment results show electricity production and consumption would increase. In consideration of the real situation and existing problems, some suggestions are proposed. The government could decrease thermal power and exploit renewable energy power, like hydroelectric power, wind power and solar power, to ensure the safe and reliable operation of China’s major power grids and protect environment

The - compromised? - future of natural gas

International Nuclear Information System (INIS)

Rodriguez, Ph.

2009-01-01

Will natural gas be the main loser of the January 2009 crisis between Ukraine and Russia? The demonstration is made that the European Union is not free from the risk of a severe supply disruption. This is a bad news considering that the power generation is the growth vector of natural gas. Even if the gas black-out cannot exist, the power black-out still can happen. As soon as the Russian-Ukrainian conflict has occurred, the other energy sources (nuclear and renewable) have been called for help in Europe while coal is in the expectation. Since some time now, gas has to face several trend changes. First, uncertainty is increasing considering its growth prospects. The new version of the gas pluri-annual indicative plan (PIP Gaz) would foresee a stagnation of gas consumption up to 2020 (consequence of the French environmental policy), while the previous plan had foreseen a 2.1% annual growth rate between 2005 and 2015. Second, the direct indexing of gas prices on oil prices can have undesirable effects. Finally, the u-turn of the USA with respect to liquefied natural gas (LNG) may penalize its development. What answers should the European Union give in front of these uncertainties? Have the companies modified their strategy? Is the future of gas still fine? These are the questions debated during a round table organized by the BIP, the French Bulletin of Petroleum Industry. (J.S.)

Wide-area measurement system-based supervision of protection schemes with minimum number of phasor measurement units.

Science.gov (United States)

Gajare, Swaroop; Rao, J Ganeswara; Naidu, O D; Pradhan, Ashok Kumar

2017-08-13

Cascade tripping of power lines triggered by maloperation of zone-3 relays during stressed system conditions, such as load encroachment, power swing and voltage instability, has led to many catastrophic power failures worldwide, including Indian blackouts in 2012. With the introduction of wide-area measurement systems (WAMS) into the grids, real-time monitoring of transmission network condition is possible. A phasor measurement unit (PMU) sends time-synchronized data to a phasor data concentrator, which can provide a control signal to substation devices. The latency associated with the communication system makes WAMS suitable for a slower form of protection. In this work, a method to identify the faulted line using synchronized data from strategic PMU locations is proposed. Subsequently, a supervisory signal is generated for specific relays in the system for any disturbance or stressed condition. For a given system, an approach to decide the strategic locations for PMU placement is developed, which can be used for determining the minimum number of PMUs required for application of the method. The accuracy of the scheme is tested for faults during normal and stressed conditions in a New England 39-bus system simulated using EMTDC/PSCAD software. With such a strategy, maloperation of relays can be averted in many situations and thereby blackouts/large-scale disturbances can be prevented.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

Study of risk reduction by improving operation of reactor core isolation cooling system

International Nuclear Information System (INIS)

Watanabe, Yamato; Tazai, Ayuko; Yamagishi, Shohei; Muramatsu, Ken; Muta, Hitoshi

2014-01-01

The Fukushima Daiichi nuclear power plant fell into a station blackout (SBO) due to the earthquake and tsunami in which most of the core cooling systems were disabled. In the units 2 and 3, water injection to the core was performed only by water injection system with turbine driven pumps. In particular, it is inferred from observed plant parameters that the reactor core isolation cooling system (RCIC) continued its operation much longer than it was originally expected (8 hours). Since the preparation of safety measures did not work, the reactor core damaged. With a view to reduce risk of station blackout events in a BWR by accident management, this study investigated the efficacy of operation procedures that takes advantage of RCIC which can be operated with only equipment inside reactor building and does not require an AC power source. The efficacy was assessed in this study by two steps. The first step is a thermal hydraulic analysis with the RETRAN3D code to estimate the potential extension of duration of core cooling by RCIC and the second step is the estimation of time required for recovery of off-site power from experiences at nuclear power stations under the 3.11 earthquake. This study showed that it is possible to implement more reliable measures for accident termination and to greatly reduce the risk of SBO by the installation of accident management measures with use of RCIC for extension of core cooling under SBO conditions. (author)

Energy–exergy and economic analyses of a hybrid solar–hydrogen renewable energy system in Ankara, Turkey

International Nuclear Information System (INIS)

Ozden, Ender; Tari, Ilker

2016-01-01

Highlights: • Uninterrupted energy in an emergency blackout situation. • System modeling of a solar–hydrogen based hybrid renewable energy system. • A comprehensive thermodynamical analysis. • Levelized cost of electricity analysis for a project lifetime of 25 years. - Abstract: A hybrid (Solar–Hydrogen) stand-alone renewable energy system that consists of photovoltaic panels (PV), Proton Exchange Membrane (PEM) fuel cells, PEM based electrolyzers and hydrogen storage is investigated by developing a complete model of the system using TRNSYS. The PV panels are mounted on a tiltable platform to improve the performance of the system by monthly adjustments of the tilt angle. The total area of the PV panels is 300 m 2 , the PEM fuel cell capacity is 5 kW, and the hydrogen storage is at 55 bars pressure and with 45 m 3 capacity. The main goal of this study is to verify that the system meets the electrical power demand of the emergency room without experiencing a shortage for a complete year in an emergency blackout situation. For this purpose, after modeling the system, energy and exergy analyses for the hydrogen cycle of the system for a complete year are performed, and the energy and exergy efficiencies are found as 4.06% and 4.25%, respectively. Furthermore, an economic analysis is performed for a project lifetime of 25 years based on Levelized Cost of Electricity (LCE), and the LCE is calculated as 0.626 $/kWh.

Additional examination on station blackout caused by tsunami in Fukushima Daiichi NPS

International Nuclear Information System (INIS)

Yamauchi, Daisuke; Date, Kenji; Mizokami, Masato; Honda, Takeshi; Nozaki, Kenichiro; Mizokami, Shinya; Endo, Ryohei

2017-01-01

This study is additional examination to verify in a more reliable way the assessment that the emergency AC power supply was lost due to tsunami at Fukushima Daiichi Nuclear Power Station. It confirmed the relationship between the path length of tsunami intrusion reaching each power supply facility and the function loss time. As a result of examination, it was confirmed that as the path length of the tsunami intrusion reaching each power supply facility was longer, the function loss time tended to be later. So, conventional assessment that the function of each power supply facility was lost due to the run-up and flooding of tsunami has become more probable. For facilities, where the overall trend and the loss time of function were divergent, it was found that there were scenarios that could reasonably be explained. Based on the fact that the Fukushima Daiichi Nuclear Power Station lost power due to the tsunami, Kashiwazaki-Kariwa Nuclear Power Station carries out various safety measures. First of all, as the measures to prevent accidents caused by tsunami, the following have been applied: (1) prevention of the inflow of tsunamis into premises, (2) water prevention of the areas installed with important equipment, (3) securement of seawater at the time of backwashing, (4) storage of portable equipment at high ground, (5) installation of tsunami surveillance cameras. To prepare for the loss of power supply, this station implemented power supply facilities such as generator cars and distribution boards, as well as the placement of power supply cars at high ground. (A.O.)

Importance Sampling Based Decision Trees for Security Assessment and the Corresponding Preventive Control Schemes: the Danish Case Study

DEFF Research Database (Denmark)

Liu, Leo; Rather, Zakir Hussain; Chen, Zhe

2013-01-01

Decision Trees (DT) based security assessment helps Power System Operators (PSO) by providing them with the most significant system attributes and guiding them in implementing the corresponding emergency control actions to prevent system insecurity and blackouts. DT is obtained offline from time...... and adopts a methodology of importance sampling to maximize the information contained in the database so as to increase the accuracy of DT. Further, this paper also studies the effectiveness of DT by implementing its corresponding preventive control schemes. These approaches are tested on the detailed model...

Vision for a self-healing power grid

Energy Technology Data Exchange (ETDEWEB)

Moslehi, Khosrow; Kumar, Ranjit

2007-07-01

Power system reliability has been thrust into the limelight by recent blackouts around the world. The social and economic costs of these failures can add up to billions of dollars every year. As the digital age prevails, more efficient manufacturing processes, based on computers and power electronics, have come to dominate industry. As the portion of electricity in the total energy consumption continues to grow, the value of power system reliability increases. This article discusses a vision for state-of-the-art solutions to improve power system reliability through improved monitoring and control. (auth)

Control and Protection Cooperation Strategy for Voltage Instability

DEFF Research Database (Denmark)

Liu, Zhou; Chen, Zhe; Sun, Haishun

2012-01-01

Most cascaded blackouts are caused by unexpected backup relay operations due to low voltage or overload state caused by post fault load restoration dynamics. If such state can be sensed and adjusted appropriately prior to those relay actions, system stability might be sustained. This paper proposed...... a control and protection cooperation strategy to prevent post fault voltage instability. The multi-agent technology is applied for the strategy implementation; the criteria based on wide area measured apparent impedances are defined to choose the control strategy, such as tap changer adjusting or load...

Adaptive Tuning of Frequency Thresholds Using Voltage Drop Data in Decentralized Load Shedding

DEFF Research Database (Denmark)

Hoseinzadeh, Bakhtyar; Faria Da Silva, Filipe Miguel; Bak, Claus Leth

2015-01-01

Load shedding (LS) is the last firewall and the most expensive control action against power system blackout. In the conventional under frequency LS (UFLS) schemes, the load drop locations are already determined independently of the event location. Furthermore, the frequency thresholds of LS relays...... are prespecified and constant values which may not be a comprehensive solution for widespread range of possible events. This paper addresses the decentralized LS in which the instantaneous voltage deviation of load buses is used to determine the frequency thresholds of LS relays. The higher frequency thresholds...

Analysis of first wall and divertor cooling loop failures for the ITER plant

International Nuclear Information System (INIS)

Eriksson, J.; Sjoberg, A.; Collen, J.

1998-01-01

In this study the capability of the in-vessel heat transfer systems to maintain sufficiently low structure temperatures during certain events have been investigated. The findings are that in the case of blackout PWF/IBB structure temperatures remain low enough not to jeopardize the integrity. In an event of divertor pump trip generally lower copper temperatures are achieved and opening of the pressurizer safety valve is avoided if a prolonged pump coasting down period is selected. However, an adequate minimum thickness of protective CFC armour is still crucial for maintaining structure integrity. (authors)

Scenario-based approach adopted in the ELECTRA project for deriving innovative control room functionality

DEFF Research Database (Denmark)

Marinelli, Mattia; Heussen, Kai; Prostejovsky, Alexander Maria

2017-01-01

Here, the authors analyse the operator point of view of the Web-of-Cells concept defined in the EU project ELECTRA, by identifying operator tasks into the supervision of a highly automated power system, and the information requirements to facilitate appropriate operator situation awareness...... have been identified based on the Web-of-Cells control concept. The authors considered scenarios that challenge traditional control schemes, scenarios that caused major failures (i.e. blackouts), and scenarios that can be expected to appear in the future. For each scenario, information concerning...

Passive system with steam-water injector for emergency supply of NPP steam generators

International Nuclear Information System (INIS)

Il'chenko, A.G.; Strakhov, A.N.; Magnitskij, D.N.

2009-01-01

The calculation results of reliability indicators of emergency power supply system and emergency feed-water supply system of serial WWER-1000 unit are presented. To ensure safe water supply to steam generators during station blackout it was suggested using additional passive emergency feed-water system with a steam-water injector working on steam generators dump steam. Calculated analysis of steam-water injector operating capacity was conducted at variable parameters of steam at the entrance to injector, corresponding to various moments of time from the beginning of steam-and-water damping [ru

Chokepoints global private regulation on the Internet

CERN Document Server

Tusikov, Natasha

2016-01-01

In January 2012, millions participated in the now-infamous "Internet blackout" against the Stop Online Piracy Act, protesting the power it would have given intellectual property holders over the Internet. However, while SOPA's withdrawal was heralded as a victory for an open Internet, a small group of corporations, tacitly backed by the US and other governments, have implemented much of SOPA via a series of secret, handshake agreements. Drawing on extensive interviews, Natasha Tusikov details the emergence of a global regime in which large Internet firms act as regulators for powerful intellec

A reliability model of the Angra 1 power system by the device of stages optimized by genetic algorithms

International Nuclear Information System (INIS)

Crossetti, Patricia Guimaraes

2006-01-01

This thesis proposes a probabilistic model to perform the reliability analysis of nuclear power plant systems under aging. This work analyses the Angra 1 power system. Systems subject to aging consist of components whose failure rates are not all constant, thus generating Non-Markovian models. Genetic algorithms were used for optimizing the application of the device of stages. Two approaches were used in the optimization, MCEF and MCEV. The results obtained for the Angra 1 power system show that the probability of a station blackout is negligible. (author)

Ailing uranium millworkers seek recognition, aid

International Nuclear Information System (INIS)

Ambler, M.

1980-01-01

Uranium millworkers who helped produce uranium for the U.S. nuclear defense program in the 1950's and 1960's are suing the federal government and uranium companies for compensation for illnesses that they believe are job-related. Symptoms of these illnesses include frequent blackouts, chronic bronchitis, asthma, constant fatigue, and susceptibility to colds. Research is being conducted to determine whether the millworkers' symptoms are due to excessive radiation exposure. Studies to date indicated that during the 1950's and early 1960's, radiation protection procedures at uranium milling facilities were extremely deficient

On the Impact of Cyberattacks on Voltage Control Coordination by ReGen Plants in Smart Grids

DEFF Research Database (Denmark)

Shahid, Kamal; Kidmose, Egon; Olsen, Rasmus Løvenstein

2017-01-01

are crucial step stones towards a future resilient power system. The ability to provide online voltage stability support from Renewable Generation plants highly depends on the communication infrastructure that allows an exchange of information between different grid assets. Any attempt to attack...... this communication system can lead to an unstable grid and in worst case, a complete blackout. Therefore, this paper illustrates the impact of cyberattacks on the voltage control coordination between the renewable generation plants and the system operator in microgrid settings. More specifically, this work focuses...

Contingency-Constrained Unit Commitmentin Meshed Isolated Power Systems

DEFF Research Database (Denmark)

Sokoler, Leo Emil; Vinter, Peter; Bærentsen, Runi

2015-01-01

is kept above a predefined limit in the event of a contingency. The minimum frequency constraints are formulated using novel sufficient conditions that take into account the system inertia and the dynamics of the power generators. The proposed sufficient conditions are attractive from both a computational...... and a modelling point of view. We compare the ORPP to a unit commitment problem that only considers the stationary behavior of the frequency. Simulations based on a Faroe Islands case study show that, without being overly conservative, potential blackouts and power outages can be avoided using the ORPP...

Alternative off-site power supply improves nuclear power plant safety

International Nuclear Information System (INIS)

Gjorgiev, Blaže; Volkanovski, Andrija; Kančev, Duško; Čepin, Marko

2014-01-01

Highlights: • Additional power supply for mitigation of the station blackout event in NPP is used. • A hydro power plant is considered as an off-site alternative power supply. • An upgrade of the probabilistic safety assessment from its traditional use is made. • The obtained results show improvement of nuclear power plant safety. - Abstract: A reliable power system is important for safe operation of the nuclear power plants. The station blackout event is of great importance for nuclear power plant safety. This event is caused by the loss of all alternating current power supply to the safety and non-safety buses of the nuclear power plant. In this study an independent electrical connection between a pumped-storage hydro power plant and a nuclear power plant is assumed as a standpoint for safety and reliability analysis. The pumped-storage hydro power plant is considered as an alternative power supply. The connection with conventional accumulation type of hydro power plant is analysed in addition. The objective of this paper is to investigate the improvement of nuclear power plant safety resulting from the consideration of the alternative power supplies. The safety of the nuclear power plant is analysed through the core damage frequency, a risk measure assess by the probabilistic safety assessment. The presented method upgrades the probabilistic safety assessment from its common traditional use in sense that it considers non-plant sited systems. The obtained results show significant decrease of the core damage frequency, indicating improvement of nuclear safety if hydro power plant is introduced as an alternative off-site power source

Heat transfer characteristics of horizontal steam generators under natural circulation conditions

International Nuclear Information System (INIS)

Hyvaerinen, J.

1996-01-01

This paper deals with the heat transfer characteristics of horizontal steam generators, particularly under natural circulation (decay heat removal) conditions on the primary side. Special emphasis is on the inherent features of horizontal steam generator behaviour. A mathematical model of the horizontal steam generator primary side is developed and qualitative results are obtained analytically. A computer code, called HSG, is developed to solve the model numerically, and its predictions are compared with experimental data. The code is employed to obtain for VVER 440 steam generators quantitative results concerning the dependence of primary-to-secondary heat transfer efficiency on the primary side flow rate, temperature and secondary level. It turns out that the depletion of the secondary inventory leads to an inherent limitation of the decay energy removal in VVER steam generators. The limitation arises as a consequence of the steam generator tube bundle geometry. As an example, it is shown that the grace period associated with pressurizer safety valve opening during a station black-out is 2 1/2-3 hours instead of the 5-6 hours reported in several earlier studies. (However, the change in core heat-up timing is much less-about 1 h at most.) The heat transfer limitation explains the fact that, in the Greifswald VVER 440 station black-out accident in 1975, the steam generators never boiled dry. In addition, the stability of single-phase natural circulation is discussed and insights on the modelling of horizontal steam generators with general-purpose thermal-hydraulic system codes are also presented. (orig.)

Intercode comparison of SBO scenario for AHWR

International Nuclear Information System (INIS)

Srivastava, A.; Kumar, Rajesh; Chatterjee, B.; Vijayan, P.K.

2015-01-01

This paper outlines the assessment of station blackout scenario for AHWR using last version of the French best estimate computer code CATHARE2/V2.5 2 and its comparison with RELAP5/mod3.2 findings. First, it explains the modelling of main heat transport system of AHWR and isolation Condenser loop along with GDWP in CATHARE2 followed by thermal hydraulic safety assessment of station blackout scenario and comparison of predictions with RELAP5 findings. The proposed Advanced Heavy Water Reactor is a 920 MWth Thorium based vertical pressure tube type boiling light water cooled and heavy water moderated reactor. One of the important passive design features of this reactor is that the heat removal is achieved through natural circulation of primary coolant at all allowed power levels with no primary coolant pumps.The prolonged SBO has been analyzed for AHWR using best estimate code CATHARE and results are compared with already available results of RELAP5 code. The ICs are able to remove decay heat with the help of GDWP and maintain core temperatures well with-in the limit. Decay heat is removed passively by GDWP initially by sensible heating and later by boil off as seen in long term calculation done with RELAP5. It has been found in that analysis, IC system is capable to remove decay heat for more than 7 days. The decay heat removal through IC path along with passive moderator and end shield cooling keeps the integrity of different system and maintains the core temperature well below the acceptance limit

Drinking game play among first-year college student drinkers: an event-specific analysis of the risk for alcohol use and problems.

Science.gov (United States)

Ray, Anne E; Stapleton, Jerod L; Turrisi, Rob; Mun, Eun-Young

2014-09-01

College students who play drinking games (DGs) more frequently report higher levels of alcohol use and experience more alcohol-related harm. However, the extent to which they are at risk for increased consumption and harm as a result of DG play on a given event after accounting for their typical DG participation, and typical and event drinking, is unclear. We examined whether first-year students consumed more alcohol and were more likely to experience consequences on drinking occasions when they played DGs. Participants (n = 336) completed up to six web-based surveys following weekend drinking events in their first semester. Alcohol use, DG play, and consequences were reported for the Friday and Saturday prior to each survey. Typical DG tendencies were controlled in all models. Typical and event alcohol use were controlled in models predicting risk for consequences. Participants consumed more alcohol on DG versus non-DG events. All students were more likely to experience blackout drinking consequences when they played DGs. Women were more likely to experience social-interpersonal consequences when they played DGs. DG play is an event-specific risk factor for increased alcohol use among first-year students, regardless of individual DG play tendencies. Further, event DG play signals increased risk for blackout drinking consequences for all students, and social-interpersonal consequences for women, aside from the amount of alcohol consumed on those occasions as well as typical drinking behaviors. Prevention efforts to reduce high-risk drinking may be strengthened by highlighting both event- and person-specific risks of DG play.

Extreme temperature events affecting the electricity distribution system of the metropolitan area of Buenos Aires (1971–2013)

International Nuclear Information System (INIS)

Santágata, Daniela M.; Castesana, Paula; Rössler, Cristina E.; Gómez, Darío R.

2017-01-01

We studied the role of cold waves and heat waves on major power outages in the metropolitan area of Buenos Aires. Impacts of events occurring in the tails of distributions were assessed estimating deviations of minimum temperature, maximum temperature and hourly electricity consumption with respect to statistically derived thresholds and using three sets of data: temperature observations (1911–2013); major power outages reported in a disaster database (1971–2013) and hourly electricity consumption (2006–2013). These deviations (exceedances) proved to be adequate indicators of the stress posed by extreme temperature events to the electricity distribution system leading to major blackouts. Based on these indicators, we found that the electricity distribution system was under similar stress during cold waves or heat waves, but it was much more vulnerable to heat waves (three blackouts under cold waves against 20 under heat waves between 2006 and 2013). For heat waves, the results of a binomial regression logistic model provided an adequate description of the probability of disastrous supply interruptions in terms of exceedances in extreme temperatures and electricity consumption stress. This approach may be of use for other cities wishing to evaluate the effects of extreme temperature events on the electricity distribution infrastructure. - Highlights: • The linkage between extreme temperatures and disastrous power outages is analyzed. • Exceedance in extreme temperature and electricity consumption are stress indicators. • Extreme temperatures pose moderate to extreme impacts to electricity distribution. • Electricity distribution is more vulnerable to heat waves than cold waves.

Seismic PRA of a BWR plant

International Nuclear Information System (INIS)

Nishio, Masahide; Fujimoto, Haruo

2014-01-01

Since the occurrence of nuclear power plant accidents in the Fukushima Daichi nuclear power station, the regulatory framework on severe accident (SA) has been discussed in Japan. The basic concept is to typify and identify the accident sequences leading to core/primary containment vessel (PCV) damage and to implement SA measures covering internal and external events extensively. As Japan is an earthquake-prone country and earthquakes and tsunami are important natural external events for nuclear safety of nuclear power plants, JNES performed the seismic probabilistic risk assessment (PRA) on a typical nuclear power plant and evaluated the dominant accident sequences leading to core/PCV damage to discuss dominant scenarios of severe accident (SA). The analytical models and the results of level-1 seismic PRA on a 1,100 MWe BWR-5 plant are shown here. Seismic PRA was performed for a typical BWR5 plant. Initiating events with large contribution to core damage frequency are the loss of all AC powers (station blackout) and the large LOCA. The top of dominant accident sequences is the simultaneous occurrence of station blackout and large LOCA. Important components to core damage frequency are electric power supply equipment. It needs to keep in mind that the results are influenced on site geologic characteristic to a greater or lesser. In the process of analysis, issues such as conservative assumptions related to damages of building or structure and success criteria for excessive LOCA are left to be resolved. These issues will be further studied including thermal hydric analysis in the future. (authors)

Study on depressurization measurements and effect in PWR

International Nuclear Information System (INIS)

Ji Duan; Cao Xuewu

2006-01-01

Implementation of new regulations on nuclear powered plant design and operation raise new design and management requirement for plants, and the operational plants also need accident management to enhance the reactor operation safety. Thus, for sake of reducing risk of high-pressure and mitigating the consequence, depressurization is a measure carried out to reduce primary pressure. With SCDAP/RELAP5 this paper studies the depressurization measurements and effect factors in pressurized water reactor under the important severe accident sequences induced by very small break lost of coolant accident (VSBLOCA), anticipated transient without scram (ATWS) and station blackout (SBO) plus auxiliary feedwater failure. (author)

Regulatory analysis for Generic Issue 23: Reactor coolant pump seal failure. Draft report for comment

Energy Technology Data Exchange (ETDEWEB)

Shaukat, S K; Jackson, J E; Thatcher, D F

1991-04-01

This report presents the regulatory/backfit analysis for Generic Issue 23 (GI-23), 'Reactor Coolant Pump Seal Failure'. A backfit analysis in accordance with 10 CFR 50.109 is presented in Appendix E. The proposed resolution includes quality assurance provisions for reactor coolant pump seals, instrumentation and procedures for monitoring seal performance, and provisions for seal cooling during off-normal plant conditions involving loss of all seal cooling such as station blackout. Research, technical data, and other analyses supporting the resolution of this issue are summarized in the technical findings report (NUREG/CR-4948) and cost/benefit report (NUREG/CR-5167). (author)

Temporal characteristic analysis of laser-modulated pulsed X-ray source for space X-ray communication

Science.gov (United States)

Hang, Shuang; Liu, Yunpeng; Li, Huan; Tang, Xiaobin; Chen, Da

2018-04-01

X-ray communication (XCOM) is a new communication type and is expected to realize high-speed data transmission in some special communication scenarios, such as deep space communication and blackout communication. This study proposes a high-speed modulated X-ray source scheme based on the laser-to-X-ray conversion. The temporal characteristics of the essential components of the proposed laser-modulated pulsed X-ray source (LMPXS) were analyzed to evaluate its pulse emission performance. Results show that the LMPXS can provide a maximum modulation rate up to 100 Mbps which is expected to significantly improve the data rate of XCOM.

Performance diagnostic system for emergency diesel generators

International Nuclear Information System (INIS)

Logan, K.P.

1991-01-01

Diesel generators are commonly used for emergency backup power at nuclear stations. Emergency diesel generators (EDGs) are subject to both start-up and operating failures, due to infrequent and fast-start use. EDG reliability can be critical to plant safety, particularly when station blackout occurs. This paper describes an expert diagnostic system designed to consistently evaluate the operating performance of diesel generators. The prototype system is comprised of a suite of sensor monitoring, cylinder combustion analyzing, and diagnostic workstation computers. On-demand assessments of generator and auxiliary equipment performance are provided along with color trend displays comparing measured performance to reference-normal conditions

Electron depletion via cathode spot dispersion of dielectric powder into an overhead plasma

International Nuclear Information System (INIS)

Gillman, Eric D.; Foster, John E.

2013-01-01

The effectiveness of cathode spot delivered dielectric particles for the purpose of plasma depletion is investigated. Here, cathode spot flows kinetically entrain and accelerate dielectric particles originally at rest into a background plasma. The time variation of the background plasma density is tracked using a cylindrical Langmuir probe biased approximately at electron saturation. As inferred from changes in the electron saturation current, depletion fractions of up to 95% are observed. This method could be exploited as a means of communications blackout mitigation for manned and unmanned reentering spacecraft as well as any high speed vehicle enveloped by a dense plasma layer

Analysis of some antecipated transients without scram for PWR type reactors by coupling of the CORAN code to the ALMOD code system

International Nuclear Information System (INIS)

Carvalho, F. de A.T. de.

1985-01-01

This study investigates some antecipated transients without scram for a pressurized water cooled reactor, using coupling of the containment CORAN code to the ALMOD code system, under severe random conditions. This coupling has the objective of including containment model as part of an unified code system. These severe conditions include failure of reactor scram, following a station black-out and emergency power initiation for the burn-up status at the beginning and end of the cycle. Furthermore, for the burn-up status at the end of the cycle, a failure in the closure of the pressurizer relief valve was also investigated. (Author) [pt

Reducing the risk of cyber threats in utilities through log management

Energy Technology Data Exchange (ETDEWEB)

Patnaik, A. [ArcSight, Cupertino, CA (United States)

2010-01-15

Electrical blackouts caused by terrorists hacking into targeted control systems have already occurred in Brazil. A patchwork of security tools is needed to reduce potential threats. The continuous collection and analysis of data is also needed to detect cyber threats. The real time correlation of logs across all systems, applications and users is needed to ensure the reliability and security of the power grid. Solutions must also integrate well with identity management sources in order to prevent remote access account hijacking. Effective log management can be used to detect threats and reduce the risk of power outages. 1 fig.

Accident analyses on TMLB' and LOCA for KNGR using MELCOR code

Energy Technology Data Exchange (ETDEWEB)

Park, Soo Yong; Choi, Y.; Ahn, K.I

2000-11-01

Plant specific phenomenological analyses for the Korean Next Generation Reactor, using MELCOR program, are described in this report. The most important two accident sequences, a station blackout and a loss of coolant scenario, are selected. Complete coverage of corium behavior both in-vessel and ex-vessel, and the corresponding containment responses, are analyzed. The in-vessel progression includes the thermal hydraulics in the primary system, core heat up, hydrogen generation, and melt progression up to the reactor vessel breach. The ex-vessel progression describes molten corium - concrete interaction phenomena and the pressure behavior in the containment atmosphere.

The relaxation of the operation restrictions at typhoon period for Taipower's nuclear power plant

International Nuclear Information System (INIS)

Wang, L.C.; Chou, L.Y.

2004-01-01

This paper analyzes the station blackout event for Taipower's nuclear power plant and proposes a plan whereby the availability of the plant at typhoon period can be increased through a systematic approach to improvements in the old operating restrictions. The conclusions have shown that the old operating restrictions were too strict and can be relaxed without increasing the likelihood of core damage or core melt for the accident sequence. After a detailed review of this analysis report, Republic of China Atomic Energy Commission (ROCAEC) has approved the relaxation of the operating restrictions as proposed by Taiwan Power Company. (author)

A study of core melting phenomena in reactor severe accident of PWR

Energy Technology Data Exchange (ETDEWEB)

Jeun, Gyoo Dong; Park, Shane; Kim, Jong Sun; Kim, Sung Joong [Hanyang Univ., Seoul (Korea, Republic of); Kim, Jin Man [Korea Maritime Univ., Busan (Korea, Republic of)

2001-03-15

In the 4th year, SCDAP/RELAP5 best estimate input data obtained from the TMI-2 accident analysis were applied to the analysis of domestic nuclear power plant. Ulchin nuclear power plant unit 3, 4 were selected as reference plant and steam generator tube rupture, station blackout SCDAP/RELAP5 calculation were performed to verify the adequacy of the best estimate input parameters and the adequacy of related models. Also, System 80+ EVSE simulation was executed to study steam explosion phenomena in the reactor cavity and EVSE load test was performed on the simplified reactor cavity geometry using TRACER-II code.

17 CFR 245.101 - Prohibition of insider trading during pension fund blackout periods.

Science.gov (United States)

2010-04-01

... termination of a derivative security that the director or executive officer did not write or acquire during... of 2002); and either: (i) The derivative security, by its terms, may be exercised, converted or... termination; or (ii) The derivative security is exercised, converted or terminated by a counterparty and the...

29 CFR 2520.101-3 - Notice of blackout periods under individual account plans.

Science.gov (United States)

2010-07-01

... security, you should give careful consideration to the importance of a well-balanced and diversified... have wider price swings, up and down, in short periods of time, than investments in diversified funds...

Laser technologies for on-site surveillance

International Nuclear Information System (INIS)

Goncalves, Joao G.M.; Sequeira, Vitor; Whichello, Julian

2001-01-01

Surveillance techniques are based on the detection of changes. These changes can be caused by moving objects or people, or by modifications made to the environment itself. Visual surveillance uses optical means, e.g., the analysis of an image acquired by a surveillance camera. These techniques are effective in detecting objects moving within the surveyed area. There are situations, however, where optical surveillance may prove to be unreliable. In some cases, the changes in the image are too small to be properly detected with scene change detectors. In other cases, alarms are generated without objects (or people) moving. These false alarms may be caused by changes in illumination, e.g., a faulty lamp or spurious reflections in places near water pools. Further, the absence of illumination during a blackout (whether it is caused by accident or on purpose) prevents cameras from their surveillance operation. There are high security installations for which it is necessary to introduce reliable, independent and effective sensors that can keep the surveillance work even during a blackout. Laser range scanners are electronic instruments measuring the distance from the instrument itself to the outside world along a specific direction. The type of the instrument to use depends on the range of distances to measure. Indeed, whereas for large distances (e.g. between 1 and 200m) it is possible to use time-of-flight instruments, for short distances (e.g., from a few centimetres to about 1.5m) a triangulation laser striping system is used. The deflection of the laser beam (e.g., using rotating mirrors) enables the acquisition of the distance profiles (or matrices) of the surrounding premises in a very short time

Post shut-down decay heat removal from nuclear reactor core by natural convection loops in sodium pool

Energy Technology Data Exchange (ETDEWEB)

Rajamani, A. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Sundararajan, T., E-mail: tsundar@iitm.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Parthasarathy, U.; Velusamy, K. [Nuclear Engineering Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2016-05-15

Highlights: • Transient simulations are performed for a worst case scenario of station black-out. • Inter-wrapper flow between various sub-assemblies reduces peak core temperature. • Various natural convection paths limits fuel clad temperatures below critical level. - Abstract: The 500 MWe Indian pool type Prototype Fast Breeder Reactor (PFBR) has a passive core cooling system, known as the Safety Grade Decay Heat Removal System (SGDHRS) which aids to remove decay heat after shut down phase. Immediately after reactor shut down the fission products in the core continue to generate heat due to beta decay which exponentially decreases with time. In the event of a complete station blackout, the coolant pump system may not be available and the safety grade decay heat removal system transports the decay heat from the core and dissipates it safely to the atmosphere. Apart from SGDHRS, various natural convection loops in the sodium pool carry the heat away from the core and deposit it temporarily in the sodium pool. The buoyancy driven flow through the small inter-wrapper gaps (known as inter-wrapper flow) between fuel subassemblies plays an important role in carrying the decay heat from the sub-assemblies to the hot sodium pool, immediately after reactor shut down. This paper presents the transient prediction of flow and temperature evolution in the reactor subassemblies and the sodium pool, coupled with the safety grade decay heat removal system. It is shown that with a properly sized decay heat exchanger based on liquid sodium and air chimney stacks, the post shutdown decay heat can be safely dissipated to atmospheric air passively.

Vulnerability to terrorist attacks in European electricity decarbonisation scenarios: Comparing renewable electricity imports to gas imports

International Nuclear Information System (INIS)

Lilliestam, Johan

2014-01-01

The decarbonised future European electricity system must remain secure: reliable electricity supply is a prerequisite for the functioning of modern society. Scenarios like Desertec, which partially rely on solar power imports from the Middle East and North Africa, may be attractive for decarbonisation, but raise concerns about terrorists interrupting supply by attacking the long, unprotected transmission lines in the Sahara. In this paper, I develop new methods and assess the European vulnerability to terrorist attacks in the Desertec scenario. I compare this to the vulnerability of today's system and a decarbonisation scenario in which Europe relies on gas imports for electricity generation. I show that the vulnerability of both gas and electricity imports is low, but electricity imports are more vulnerable than gas imports, due to their technical characteristics. Gas outages (and, potentially, resulting blackouts) are the very unlikely consequence even of very high-number attacks against the gas import system, whereas short blackouts are the potential consequence of a few attacks against the import electricity lines. As the impacts of all except extreme attacks are limited, terrorists cannot attack energy infrastructure and cause spectacular, fear-creating outages. Both gas and electricity import infrastructure are thus unattractive and unlikely terrorist targets. - Highlights: • A comparison of terrorism risks of importing solar power and gas for power generation. • Both scenarios show low vulnerability to terrorist attacks. • Within low vulnerabilities, gas imports are less vulnerable than electricity imports. • Causing spectacular, large and long outages is very difficult for attacker. • The attractiveness of gas and power import infrastructure as terrorist target is low

Review of Public Safety in Viewpoint of Complex Networks

International Nuclear Information System (INIS)

Gai Chengcheng; Weng Wenguo; Yuan Hongyong

2010-01-01

In this paper, a brief review of public safety in viewpoint of complex networks is presented. Public safety incidents are divided into four categories: natural disasters, industry accidents, public health and social security, in which the complex network approaches and theories are need. We review how the complex network methods was developed and used in the studies of the three kinds of public safety incidents. The typical public safety incidents studied by the complex network methods in this paper are introduced, including the natural disaster chains, blackouts on electric power grids and epidemic spreading. Finally, we look ahead to the application prospects of the complex network theory on public safety.

One year of Italian press review in the energy domain; Une annee de revue de presse italienne dans le domaine de l'energie

Energy Technology Data Exchange (ETDEWEB)

Augier, L.; Perna, N.; Carles, R.

2004-03-01

In terms of energy, 2003 has been an important and key year for Italy with a highlight: the black-out of September 28, 2003 which has paralyzed part of Italy. This event has led to think about the necessity for Italy to diversify its energy sources. This requires a reinforcement of energy efficiency, a rational use of energy, a policy of construction of new facilities, the use of biomass fuels and the promotion of renewable energy sources. This report groups together the overall brief news written by the scientific service of the French Embassy in Italy about this topic and spread to the readers of electronic bulletins. (J.S.)

Passive cooling applications for nuclear power plants using pulsating steam-water heat pipes

International Nuclear Information System (INIS)

Aparna, J.; Chandraker, D.K.

2015-01-01

Gen IV reactors incorporate passive principles in their system design as an important safety philosophy. Passive safety systems use inherent physical phenomena for delivering the desired safe action without any external inputs or intrusion. The accidents in Fukushima have renewed the focus on passive self-manageable systems capable of unattended operation, for long hours even in extended station blackout (SBO) and severe accident conditions. Generally, advanced reactors use water or atmospheric air as their ultimate heat sink and employ passive principles in design for enhanced safety. This paper would be discussing the experimental results on pulsating steam water heat-pipe devices and their applications in passive cooling. (author)

Fusion

CERN Document Server

Mahaffey, James A

2012-01-01

As energy problems of the world grow, work toward fusion power continues at a greater pace than ever before. The topic of fusion is one that is often met with the most recognition and interest in the nuclear power arena. Written in clear and jargon-free prose, Fusion explores the big bang of creation to the blackout death of worn-out stars. A brief history of fusion research, beginning with the first tentative theories in the early 20th century, is also discussed, as well as the race for fusion power. This brand-new, full-color resource examines the various programs currently being funded or p

Program plan for environmental qualification of mechanical and dynamic (including seismic) qualification of mechanical and electrical equipment program (EDQP)

International Nuclear Information System (INIS)

Weidenhamer, G.H.

1986-06-01

The equipment qualification program described in this plan is intended to provide the technical basis for resolving uncertainties in existing equipment qualification standards. In addition, research results are contributing to the resolution of safety issues GI-23, GI-87, USI-A44, titled, ''Reactor Coolant Pump Seal Failure,'' ''Failure of HPCI Steam Line Without Isolation,'' and ''Station Blackout,'' respectively. Also, research effort is being directed at providing information on the behavior of containment isolation valves under severe accident environments. Although the results of the latter research will not contribute to resolving uncertainties in qualification standards, it has proven cost effective to obtain this information under this program

Early results of microwave transmission experiments through an overly dense rectangular plasma sheet with microparticle injection

Energy Technology Data Exchange (ETDEWEB)

Gillman, Eric D., E-mail: eric.gillman.ctr@nrl.navy.mil [National Research Council Postdoctoral Associate at the U.S. Naval Research Laboratory, Washington, DC 20375 (United States); Amatucci, W. E. [U.S. Naval Research Laboratory, Washington, DC 20375 (United States)

2014-06-15

These experiments utilize a linear hollow cathode to create a dense, rectangular plasma sheet to simulate the plasma layer surrounding vehicles traveling at hypersonic velocities within the Earth's atmosphere. Injection of fine dielectric microparticles significantly reduces the electron density and therefore lowers the electron plasma frequency by binding a significant portion of the bulk free electrons to the relatively massive microparticles. Measurements show that microwave transmission through this previously overly dense, impenetrable plasma layer increases with the injection of alumina microparticles approximately 60 μm in diameter. This method of electron depletion is a potential means of mitigating the radio communications blackout experienced by hypersonic vehicles.

Laboratory simulation of laser propagation through plasma sheaths containing ablation particles of ZrB2-SiC-C during hypersonic flight.

Science.gov (United States)

Zang, Qing; Bai, Xiangxing; Ma, Ping; Huang, Jie; Ma, Jing; Yu, Siyuan; Shi, Hongyan; Sun, Xiudong; Liu, Yang; Lu, Yueguang

2017-02-15

The optical communication method has potential for solving the blackout problem, which is a big challenge faced in the development of aerospace. Two laser transmission systems were set up to explore the influence of the plasma and the ablation particles on the propagation of the laser. The experimental results indicate that the laser can transmit through the plasma with little attenuation. When there are ablation particles of ZrB2-SiC-C added in the plasma, the intensity of the laser has fluctuations. The work introduced in this Letter can be regarded as basic research of the propagation characters of the laser through plasma sheaths.

Electrical systems design applications on Japanese PWR plants in light of the Fukushima Daiichi Accident

International Nuclear Information System (INIS)

Nomoto, Tsutomu

2015-01-01

After the Fukushima Daiichi nuclear power plant (1F-NPP) accident (i.e. Station Blackout), several design enhancements have been incorporated or are under considering to Mitsubishi PWR plants' design of not only operational plants' design but also new plants' design. Especially, there are several important enhancements in the area of the electrical system design. In this presentation, design enhancements related to following electrical systems/equipment are introduced; - Offsite Power System; - Emergency Power Source; - Safety-related Battery; - Alternative AC Power Supply Systems. In addition, relevant design requirements/conditions which are or will be considered in Mitsubishi PWR plants are introduced. (authors)

Mechanical structure and problem of thorium molten salt reactor

International Nuclear Information System (INIS)

Kamei, Takashi

2011-01-01

After Fukushima Daiichi accident, there became great interest in Thorium Molten Salt Reactor (MSR) for the safety as station blackout leading to auto drainage of molten salts with freeze valve. This article described mechanical structure of MSR and problems of materials and pipes. Material corrosion problem by molten salts would be solved using modified Hastelloy N with Ti and Nb added, which should be confirmed by operation of an experimental reactor. Trends in international activities of MSR were also referred including China declaring MSR development in January 2011 to solve thorium contamination issues at rare earth production and India rich in thorium resources. (T. Tanaka)

Concept of safety related I and C and power supply systems in the passive safety concept of the HTR-module

International Nuclear Information System (INIS)

Juengst, U.

1990-01-01

The main motivation for the passive safety concepts is to gain a better quality of safety or at least to achieve higher public acceptance for nuclear power plants. This strategy has been introduced into the European Fast Reactor (EER), a common project of France, UK and Germany is applied stringently to the German high-temperature gas-cooled reactor ''HTR - Module''. The following fields are briefly described in the paper: Safety design features of the HTR - Module, overview of I and C concept, reactor protection system, emergency control room, power supply concept, system arrangement and protection against external hazards, accidents sequence of station black-out. (author). 3 figs

Verification of voltage/ frequency requirement for emergency diesel generator in nuclear power plant using dynamic modeling

International Nuclear Information System (INIS)

Hur, J.S.; Roh, M.S.

2013-01-01

Full-text: One major cause of the plant shutdown is the loss of electrical power. The study is to comprehend the coping action against station blackout including emergency diesel generator, sequential loading of safety system and to ensure that the emergency diesel generator should meet requirements, especially voltage and frequency criteria using modeling tool. This paper also considered the change of the sequencing time and load capacity only for finding electrical design margin. However, the revision of load list must be verified with safety analysis. From this study, it is discovered that new load calculation is a key factor in EDG localization and in-house capability increase. (author)

Technical and political aspects of the generation of electrical energy in the USA

International Nuclear Information System (INIS)

Ullmann, K.

1990-01-01

The north-east black-out in the 1960s, the Arab oil embargo at the beginning of the 1970s and the nuclear accident at Three Mile Island in the 1970s have profoundly affected the electricity supply industry in the United States. This paper explains the effects of these events on the electricity supply industry from the socio-economic and political points of view. The development trends affecting the present structure of the supply industry are indicated in the context of environmental factors. The technical development of power plant equipment and -systems and also of alternative energy sources in the light of these factors are discussed. (orig.) [de

Catalogue of requirements for a plant-specific safety inspection of German nuclear power plants taking into account the Fukushima-I (Japan) events; Anforderungskatalog fuer anlagenbezogene Ueberpruefungen deutscher Kernkraftwerke unter Beruecksichtigung der Ereignisse in Fukushima-I (Japan)

Energy Technology Data Exchange (ETDEWEB)

NONE

2011-03-30

The catalogue of requirements for a plant-specific safety inspection of German nuclear power plants taking into account the Fukushima-I (Japan) events worked out by the German RSK (reactor safety commission) includes the following inspection topics: natural events like earth quakes, floods, weather-based consequences and possible superposition; civilization-based events like airplane crash, gas release, reactor accident consequences for neighboring units, terroristic impacts, external attacks on computer-based control systems. Further event-independent assumptions have to be considered: station blackout, long-term emergency power supply requirement, failure of auxiliary cooling water supply, efficacy of preventive measures, aggravating boundary conditions for the performance of emergency measures.

Analysis of SBO accident and natural circulation of 49-2 swimming pool reactor

International Nuclear Information System (INIS)

Wu Yuanyuan; Liu Tiancai; Sun Wei

2012-01-01

The transient thermal hydraulic characteristics of 49-2 Swimming Pool Reactor (SPR) were analyzed by RELAP5/MOD3.3 code to verify the capability of natural circulation and minus reactivity feedback for accident mitigation under the condition of station blackout (SBO). Then, the effects on accident consequence and sequence for core channels and primary pumps were briefly discussed. The calculation results show that the reactor can be shutdown by the effect of minus reactivity feedback, and the residual heat can be removed through the stable natural circulation. Therefore, it demonstrates that the 49-2 SPR is safe during the accident of SBO. (authors)

Thermal-Hydraulic Analyses of Transients in an Actinide-Burner Reactor Cooled by Forced Convection of Lead Bismuth

Energy Technology Data Exchange (ETDEWEB)

Davis, Cliff Bybee

2003-09-01

The Idaho National Engineering and Environmental Laboratory (INEEL) and the Massachusetts Institute of Technology (MIT) are investigating the suitability of lead or lead–bismuth cooled fast reactors for producing low-cost electricity as well as for actinide burning. The current analysis evaluated a pool type design that relies on forced circulation of the primary coolant, a conventional steam power conversion system, and a passive decay heat removal system. The ATHENA computer code was used to simulate various transients without reactor scram, including a primary coolant pump trip, a station blackout, and a step reactivity insertion. The reactor design successfully met identified temperature limits for each of the transients analyzed.

Detecting and mitigating inverter aging

International Nuclear Information System (INIS)

Gunther, W.E.; Taylor, J.H.; Aggarwal, S.K.

1988-01-01

Nuclear power plants use inverters to supply power to safety-related equipment, instrumentation, and controls. They convert direct current (dc) to alternating current (ac) power, thereby making low voltage ac power available even under a station blackout condition. As part of the U.S. NRC's nuclear plant aging research (NPAR) program, the operating experience of this equipment has been analyzed to determine the dominant failure modes and causes. This paper summarizes that data, and then describes methods which can be employed to detect inverter degradation prior to failure, as well as methods to minimize the failure effects. In both cases, the mitigation of inverter aging is emphasized

Pearl Harbor and America's Homefront Children: First Fears, Blackouts, Air Raid Drills, and Nightmares.

Science.gov (United States)

Tuttle, William M., Jr.

In conducting research about U.S. homefront children during the Second World War, a professor of history wrote to the 100 largest-circulation newspapers in the United States as well as 75 African-American, Hispanic American, and Jewish-American newspapers and magazines seeking letters from people who experienced the War as children. More than…

The RISMC approach to perform advanced PRA analyses - 15332

International Nuclear Information System (INIS)

Mandelli, D.; Smith, C.; Riley, T.; Nielsen, J.; Alfonsi, A.; Rabiti, C.; Cogliati, J.

2015-01-01

The existing fleet of nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power up-rates. In order to evaluate the impact of these two factors on the safety of the plant, the RISMC (Risk Informed Safety Margin Characterization) Pathway aims to develop simulation-based tools and methods to assess risks for existing nuclear power plants in order to optimize safety. This pathway, by developing new methods, is extending the state-of-the-practice methods that have been traditionally based on logic structures such as Event-Trees and Fault-Trees. These static types of models mimic system response in an inductive and deductive way respectively, yet are restrictive in the ways they can represent spatial and temporal constructs. RISMC analyses are performed by using a combination of thermal-hydraulic codes and a stochastic analysis tool (RAVEN)currently under development at the Idaho National Laboratory. This paper presents a case study in order to show the capabilities of the RISMC methodology to assess impact of power up-rate of a boiling water reactor system during a station blackout accident scenario. We employ the system simulator code, RELAP5-3D, coupled with RAVEN which perform the stochastic analysis. Our analysis is in fact performed by: 1) sampling values of a set of parameters from the uncertainty space of interest, 2) simulating the system behavior for that specific set of parameter values and 3) analyzing the set of simulation runs. Results obtained give a detailed investigation of the issues associated with a plant power up-rate including the effects of station blackout accident scenarios. We are able to quantify how the timing of specific events was impacted by a higher nominal reactor core power. Such safety insights can provide useful information to the decision makers to perform risk informed margins management

Multidimensional Risk Management for Underground Electricity Networks

Directory of Open Access Journals (Sweden)

Garcez Thalles V.

2014-08-01

Full Text Available In the paper we consider an electricity provider company that makes decision on allocating resources on electric network maintenance. The investments decrease malfunction rate of network nodes. An accidental event (explosion, fire, etc. or a malfunctioning on underground system can have various consequences and in different perspectives, such as deaths and injuries of pedestrians, fires in nearby locations, disturbances in the flow of vehicular traffic, loss to the company image, operating and financial losses, etc. For this reason it is necessary to apply an approach of the risk management that considers the multidimensional view of the consequences. Furthermore an analysis of decision making should consider network dependencies between the nodes of the electricity distribution system. In the paper we propose the use of the simulation to assess the network effects (such as the increase of the probability of other accidental event and the occurrence of blackouts of the dependent nodes in the multidimensional risk assessment in electricity grid. The analyzed effects include node overloading due to malfunction of adjacent nodes and blackouts that take place where there is temporarily no path in the grid between the power plant and a node. The simulation results show that network effects have crucial role for decisions in the network maintenance – outcomes of decisions to repair a particular node in the network can have significant influence on performance of other nodes. However, those dependencies are non-linear. The effects of network connectivity (number of connections between nodes on its multidimensional performance assessment depend heavily on the overloading effect level. The simulation results do not depend on network type structure (random or small world – however simulation outcomes for random networks have shown higher variance compared to small-world networks.

Optimal operation of hybrid-SITs under a SBO accident

International Nuclear Information System (INIS)

Jeon, In Seop; Heo, Sun; Kang, Hyun Gook

2016-01-01

Highlights: • Operation strategy of hybrid-SIT (H-SIT) in station blackout (SBO) is developed. • There are five main factors which have to be carefully treated in the development of the operation strategy. • Optimal value of each main factor is investigated analytically and then through thermal-hydraulic analysis using computer code. • The optimum operation strategy is suggested based on the optimal value of the main factors. - Abstract: A hybrid safety injection tank (H-SIT) is designed to enhance the capability of pressurized water reactors against high-pressure accidents which might be caused by the combined accidents accompanied by station blackout (SBO), and is suggested as a useful alternative to electricity-driven motor injection pumps. The main purpose of the H-SIT is to provide coolant to the core so that core safety can be maintained for a longer period. As H-SITs have a limited inventory, their efficient use in cooling down the core is paramount to maximize the available time for long-term cooling component restoration. Therefore, an optimum operation strategy must be developed to support the operators for the most efficient H-SIT use. In this study, the main factors which have to be carefully treated in the development of an operation strategy are first identified. Then the optimal value of each main factor is investigated analytically, a process useful to get the basis of the global optimum points. Based on these analytical optimum points, a thermal-hydraulic analysis using MARS code is performed to get more accurate values and to verify the results of the analytical study. The available time for long-term cooling component restoration is also estimated. Finally, an integrated optimum operation strategy for H-SITs in SBO is suggested.

Electromagnetic pulse research on electric power systems: Program summary and recommendations

Energy Technology Data Exchange (ETDEWEB)

Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. (Oak Ridge National Lab., TN (United States)); Tesche, F.M. (Tesche (F.M.), Dallas, TX (United States)); Vance, E.F. (Vance (E.F.), Fort Worth, TX (United States))

1993-01-01

A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation's power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation's electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

Electromagnetic pulse research on electric power systems: Program summary and recommendations. Power Systems Technology Program

Energy Technology Data Exchange (ETDEWEB)

Barnes, P.R.; McConnell, B.W.; Van Dyke, J.W. [Oak Ridge National Lab., TN (United States); Tesche, F.M. [Tesche (F.M.), Dallas, TX (United States); Vance, E.F. [Vance (E.F.), Fort Worth, TX (United States)

1993-01-01

A single nuclear detonation several hundred kilometers above the central United States will subject much of the nation to a high-altitude electromagnetic pulse (BENT). This pulse consists of an intense steep-front, short-duration transient electromagnetic field, followed by a geomagnetic disturbance with tens of seconds duration. This latter environment is referred to as the magnetohydrodynamic electromagnetic pulse (NMENT). Both the early-time transient and the geomagnetic disturbance could impact the operation of the nation`s power systems. Since 1983, the US Department of Energy has been actively pursuing a research program to assess the potential impacts of one or more BENT events on the nation`s electric energy supply. This report summarizes the results of that program and provides recommendations for enhancing power system reliability under HENT conditions. A nominal HENP environment suitable for assessing geographically large systems was developed during the program and is briefly described in this report. This environment was used to provide a realistic indication of BEMP impacts on electric power systems. It was found that a single high-altitude burst, which could significantly disturb the geomagnetic field, may cause the interconnected power network to break up into utility islands with massive power failures in some areas. However, permanent damage would be isolated, and restoration should be possible within a few hours. Multiple bursts would likely increase the blackout areas, component failures, and restoration time. However, a long-term blackout of many months is unlikely because major power system components, such as transformers, are not likely to be damaged by the nominal HEND environment. Moreover, power system reliability, under both HENT and normal operating conditions, can be enhanced by simple, and often low cost, modifications to current utility practices.

Modernizing Distribution System Restoration to Achieve Grid Resiliency Against Extreme Weather Events: An Integrated Solution

Energy Technology Data Exchange (ETDEWEB)

Chen, Chen; Wang, Jianhui; Ton, Dan

2017-07-07

Recent severe power outages caused by extreme weather hazards have highlighted the importance and urgency of improving the resilience of the electric power grid. As the distribution grids still remain vulnerable to natural disasters, the power industry has focused on methods of restoring distribution systems after disasters in an effective and quick manner. The current distribution system restoration practice for utilities is mainly based on predetermined priorities and tends to be inefficient and suboptimal, and the lack of situational awareness after the hazard significantly delays the restoration process. As a result, customers may experience an extended blackout, which causes large economic loss. On the other hand, the emerging advanced devices and technologies enabled through grid modernization efforts have the potential to improve the distribution system restoration strategy. However, utilizing these resources to aid the utilities in better distribution system restoration decision-making in response to extreme weather events is a challenging task. Therefore, this paper proposes an integrated solution: a distribution system restoration decision support tool designed by leveraging resources developed for grid modernization. We first review the current distribution restoration practice and discuss why it is inadequate in response to extreme weather events. Then we describe how the grid modernization efforts could benefit distribution system restoration, and we propose an integrated solution in the form of a decision support tool to achieve the goal. The advantages of the solution include improving situational awareness of the system damage status and facilitating survivability for customers. The paper provides a comprehensive review of how the existing methodologies in the literature could be leveraged to achieve the key advantages. The benefits of the developed system restoration decision support tool include the optimal and efficient allocation of repair crews

Effectiveness of containment sprays in containment management

International Nuclear Information System (INIS)

Nourbakhsh, H.P.; Perez, S.E.; Lehner, J.R.

1993-05-01

A limited study has been performed assessing the effectiveness of containment sprays-to mitigate particular challenges which may occur during a severe accident. Certain aspects of three specific topics related to using sprays under severe accident conditions were investigated. The first was the effectiveness of sprays connected to an alternate water supple and pumping source because the actual containment spray pumps are inoperable. This situation could occur during a station blackout. The second topic concerned the adverse as well as beneficial effects of using containment sprays during severe accident scenario where the containment atmosphere contains substantial quantities of hydrogen along with steam. The third topic was the feasibility of using containment sprays to moderate the consequences of DCH

Resilience of nuclear power plants to withstand large earthquakes: an overview

International Nuclear Information System (INIS)

Usmani, A.; Saudy, A.

2013-01-01

This paper provides an overview of the experience gained from seismic assessments, component testing, insights from probabilistic seismic hazard analysis (PSHA), seismic PRAs and performance of structures, systems and components (SSCs) in actual earthquakes many of which have been very large and exceeded the plant design basis. The recent Fukushima earthquake has focused attention of the nuclear industry to assess and make provisions to cope with the beyond design basis events that lead to station blackout, flooding and loss of heat sinks. Based on the review of available information, the paper discusses assessments and strategies being followed by various countries. Recommendations are made to focus attention to the most vulnerable SSCs in a nuclear power plant. (author)

Energy solutions for sustainable development. Proceedings

Energy Technology Data Exchange (ETDEWEB)

Soenderberg Petersen, L; Larsen, Hans [eds.

2007-05-15

The Risoe International Energy Conference took place 22 - 24 May 2007. The conference focused on: 1) Future global energy development options. 2) Scenario and policy issues. 3) Measures to achieve low-level stabilization at, for example, 500 ppm CO2 concentrations in the atmosphere. 4) Local energy production technologies such as fuel cells, hydrogen, bio-energy and wind energy. 5) Centralized energy technologies such as clean coal technologies. 6) Providing renewable energy for the transport sector. 7) Systems aspects, differences between the various major regions throughout the world. 8) End-use technologies, efficiency improvements and supply links. 9) Security of supply with regard to resources, conflicts, black-outs, natural disasters and terrorism. (au)

Resilience of nuclear power plants to withstand large earthquakes: an overview

Energy Technology Data Exchange (ETDEWEB)

Usmani, A.; Saudy, A., E-mail: Aman.Usmani@amec.com [AMEC NSS, Power and Process Americas, Toronto, Ontario (Canada)

2013-07-01

This paper provides an overview of the experience gained from seismic assessments, component testing, insights from probabilistic seismic hazard analysis (PSHA), seismic PRAs and performance of structures, systems and components (SSCs) in actual earthquakes many of which have been very large and exceeded the plant design basis. The recent Fukushima earthquake has focused attention of the nuclear industry to assess and make provisions to cope with the beyond design basis events that lead to station blackout, flooding and loss of heat sinks. Based on the review of available information, the paper discusses assessments and strategies being followed by various countries. Recommendations are made to focus attention to the most vulnerable SSCs in a nuclear power plant. (author)

Severe accident analysis for level 2 PSA of SMART reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Jin Yong; Lee, Jeong Hun; Kim, Jong Uk; Yoo, Tae Geun; Chung, Soon Il; Kim, Min Gi [FNC Technology Co., Seoul (Korea, Republic of)

2010-12-15

The objectives of this study are to produce data for level 2 PSA and evaluation results of severe accident by analyzing severe accident sequence of transient events, producing fault tree of containment systems and evaluating direct containment heating of the SMART. In this project, severe accident analysis results were produced for general transient, loss of feedwater, station blackout, and steam line break events, and based on the results, design safety of SMART was verified. Also, direct containment heating phenomenon of the SMART was evaluated using TCE methodology. For level 2 PSA, fault tree of the containment isolation system, reactor cavity flooding system, plant chilled water system, and reactor containment building HVAC system was produced and analyzed

The use of influence diagrams for evaluating severe accident management strategies

International Nuclear Information System (INIS)

Jae, M.; Apostolakis, G.E.

1992-01-01

In this paper, the influence diagram, a new analytical tool for developing and evaluating severe accident management strategies, is presented. Influence diagrams are much simpler than decision trees because they do not lead to the large number of branches that are generated when decision trees are used in realistic problems; furthermore, they show explicitly the dependencies between the variables of the problem. One of the accident management strategies proposed for light water reactors, flooding the reactor cavity as a means of preventing vessel breach during a short-term station blackout sequence, is presented. The influence diagram associated with this strategy is constructed. Finally, the advantages of using influence diagrams in accident management are explored

Final report of the inter institutional project ININ-CNSNS 'Source Terms specific for the CNLV'; Informe final del proyecto interinstitucional ININ-CNSNS 'Termino Fuente especifico para la CNLV'

Energy Technology Data Exchange (ETDEWEB)

Anaya M, R A [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

1991-02-15

The purpose of the project inter institutional ININ-CNSNS 'Source Terms Specifies for the CNLV' it is the one of implanting in the computer CYBER (CDC 180-830) of the ININ, the 'Source Term Code Package' (STCP) and to make the operation tests and corresponding operation using the data of the sample problem, for finally to liberate the package, all time that by means of the analysis of the results it is consider appropriate. In this report the results of the are presented simulation of the sequence 'Energy Losses external' (Station blackout) and 'Lost total of CA with failure of the RCIC and success of the HPCS' both with data of the Laguna Verde Central. (Author)

Final report of the inter institutional project ININ-CNSNS 'Source Terms specific for the CNLV'

International Nuclear Information System (INIS)

Anaya M, R.A.

1991-02-01

The purpose of the project inter institutional ININ-CNSNS 'Source Terms Specifies for the CNLV' it is the one of implanting in the computer CYBER (CDC 180-830) of the ININ, the 'Source Term Code Package' (STCP) and to make the operation tests and corresponding operation using the data of the sample problem, for finally to liberate the package, all time that by means of the analysis of the results it is consider appropriate. In this report the results of the are presented simulation of the sequence 'Energy Losses external' (Station blackout) and 'Lost total of CA with failure of the RCIC and success of the HPCS' both with data of the Laguna Verde Central. (Author)

Power grid complexity

Energy Technology Data Exchange (ETDEWEB)

Mei, Shengwei; Zhang, Xuemin [Tsinghua Univ., Beijing, BJ (China). Dept. of Electrical Engineering; Cao, Ming [Groningen Univ. (Netherlands). Faculty of Mathematics and Natural Sciences

2011-07-01

''Power Grid Complexity'' introduces the complex system theory known as self-organized criticality (SOC) theory and complex network theory, and their applications to power systems. It studies the network characteristics of power systems, such as their small-world properties, structural vulnerability, decomposition and coordination strategies, and simplification and equivalence methods. The book also establishes four blackout models based on SOC theory through which the SOC of power systems is studied at both the macroscopic and microscopic levels. Additionally, applications of complex system theory in power system planning and emergency management platforms are also discussed in depth. This book can serve as a useful reference for engineers and researchers working with power systems. (orig.)

A neural networks based ``trip`` analysis system for PWR-type reactors; Um sistema de analise de ``trip`` em reatores PWR usando redes neuronais

Energy Technology Data Exchange (ETDEWEB)

Alves, Antonio Carlos Pinto Dias

1993-12-31

The analysis short after automatic shutdown (trip) of a PWR-type nuclear reactor takes a considerable amount of time, not only because of the great number of variables involved in transients, but also the various equipment that compose a reactor of this kind. On the other hand, the transients`inter-relationship, intended to the detection of the type of the accident is an arduous task, since some of these accidents (like loss of FEEDWATER and station BLACKOUT, for example), generate transients similar in behavior (as cold leg temperature and steam generators mixture levels, for example). Also, the sequence-of-events analysis is not always sufficient for correctly pin point the causes of the trip. (author) 11 refs., 39 figs.

Severe accident sequence assessment for boiling water reactors: program overview

International Nuclear Information System (INIS)

Fontana, M.H.

1980-10-01

The Severe Accident Sequence Assessment (SASA) Program was started at the Oak Ridge National Laboratory (ORNL) in June 1980. This report documents the initial planning, specification of objectives, potential uses of the results, plan of attack, and preliminary results. ORNL was assigned the Brown's Ferry Unit 1 Plant with the station blackout being the initial sequence set to be addressed. This set includes: (1) loss of offsite and onsite ac power with no coolant injection; and (2) loss of offsite and onsite ac power with high pressure coolant injection (HPCI) and reactor core isolation cooling (RCIC) as long as dc power supply lasts. This report includes representative preliminary results for the former case

Recovery of the electric supply in the SBO event of prolonged in NPP Almaraz; Recuperacion del suministro electrico en caso de SBO prolongado en CN Almaraz

Energy Technology Data Exchange (ETDEWEB)

Alejo Silvo, J. M.; Garcia Galarraga, M.

2013-07-01

In the framework of strategies of defence in depth and in response to the complementary technical instructions of the Consejo de Seguridad Nuclear (CSN) carried out after the tests of resistance, Almaraz NPP has implemented a series of modifications in order to deal with events of total loss of power Electric, Station blackout (SBO), over a long period of time, beyond the foundations of design. The purpose of modifications in Almaraz NPP is the creation of a supply infrastructure independent of the existing plant, which can attach portable external sources to supply power to a series of considered to be receptors of importance for the monitoring and maintenance of the plant in a safe condition.

A neural networks based ``trip`` analysis system for PWR-type reactors; Um sistema de analise de ``trip`` em reatores PWR usando redes neuronais

Energy Technology Data Exchange (ETDEWEB)

Alves, Antonio Carlos Pinto Dias

1994-12-31

The analysis short after automatic shutdown (trip) of a PWR-type nuclear reactor takes a considerable amount of time, not only because of the great number of variables involved in transients, but also the various equipment that compose a reactor of this kind. On the other hand, the transients`inter-relationship, intended to the detection of the type of the accident is an arduous task, since some of these accidents (like loss of FEEDWATER and station BLACKOUT, for example), generate transients similar in behavior (as cold leg temperature and steam generators mixture levels, for example). Also, the sequence-of-events analysis is not always sufficient for correctly pin point the causes of the trip. (author) 11 refs., 39 figs.

Increase of Power System Survivability with the Decision Support Tool CRIPS Based on Network Planning and Simulation Program PSS®SINCAL

Science.gov (United States)

Schwaegerl, Christine; Seifert, Olaf; Buschmann, Robert; Dellwing, Hermann; Geretshuber, Stefan; Leick, Claus

The increased interconnection and automation of critical infrastructures enlarges the complexity of the dependency structures and - as consequence - the danger of cascading effects, e.g. causing area-wide blackouts in power supply networks that are currently after deregulation operated closer to their limits. New tools or an intelligent combination of existing approaches are required to increase the survivability of critical infrastructures. Within the IRRIIS project the expert system CRIPS was developed based on network simulations realised with PSS®SINCAL, an established tool to support the analysis and planning of electrical power, gas, water or heat networks. CRIPS assesses the current situation in power supply networks analysing the simulation results of the physical network behaviour and recommends corresponding decisions.

Structure of a scheme of emergency control to avoid blackout due to interconnection lines loss

Energy Technology Data Exchange (ETDEWEB)

Luz, L.T. da; Werberich, L C; Herve, H M [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul (CEEE), Porto Alegre, RS (Brazil)

1994-12-31

This work presents the structure of Gravatai Emergency Control Scheme (ECS) with short about its development and operation. This ECS was made to avoid two kinds of problems for the systems of Companhia Estadual de Energia Eletrica (CEEE). The first one is the voltage collapse that happens after the opening of one of the 525 kv LTs of the interconnection with the Brazilian Interconnected System (BIS). The second one is the CEEE isolating after the 525 kV network loss. We show the ECS existence reason and we describe its functional structure, the substations, the circuits and the amount of load shedding involved by the system. Finally, we present the project of a control structure based on microcomputer which is being developed for this ECS. (author) 3 refs., 11 figs.

Station blackout: Deterministic and probabilistic approach in the field of electrical supply losses by EDF

International Nuclear Information System (INIS)

Meslin, T.; Carnino, A.

1986-01-01

This example shows the thoroughness of EDF's approach in processing the difficult problems of the loss of electrical power supplies. Efforts are continuing in several directions: continued revision and improvement of operating procedures in the event of loss of electrical power supplies, PWR plant operator training courses devoted to the problems of power supply losses, and continued testing on simulators, and particularly testing under real conditions, including tests lasting several hours made possible by the performance of the new EDF simulators (two-phase code and taking all power losses into account)

A flooding induced station blackout analysis for a pressurized water reactor using the RISMC toolkit

International Nuclear Information System (INIS)

Mandelli, Diego; Prescott, Steven; Smith, Curtis; Alfonsi, Andrea; Rabiti, Cristian; Cogliati, Joshua; Kinoshita, Robert

2015-01-01

In this paper we evaluate the impact of a power uprate on a pressurized water reactor (PWR) for a tsunami-induced flooding test case. This analysis is performed using the RISMC toolkit: the RELAP-7 and RAVEN codes. RELAP-7 is the new generation of system analysis codes that is responsible for simulating the thermal-hydraulic dynamics of PWR and boiling water reactor systems. RAVEN has two capabilities: to act as a controller of the RELAP-7 simulation (e.g., component/system activation) and to perform statistical analyses. In our case, the simulation of the flooding is performed by using an advanced smooth particle hydrodynamics code called NEUTRINO. The obtained results allow the user to investigate and quantify the impact of timing and sequencing of events on system safety. The impact of power uprate is determined in terms of both core damage probability and safety margins

WWER-440 reactor emergency cooling using `feed and bleed` procedure; Avarijnoe raskholazhivanie reaktora WWER-440 s pomoshtyu protsedury `podpitka-produvka`

Energy Technology Data Exchange (ETDEWEB)

Marinov, M; Dimitrov, B; Popov, E; Avdzhiev, K [Energoproekt, Sofia (Bulgaria)

1996-12-31

A procedure for emergency cooling in the case of total loss of coolant water is proposed. `Feed and bleed` procedure is applied by the operator and its main goal is to maintain a predefined level in the primary circuit and low pressure and temperature in the reactor. Two extreme cases are considered: 1. the loss of coolant is combined with a blackout; 2. the loss of feeding water is due to a general failure in the control room. The accidents are simulated and the relevant time intervals are estimated. After a simulated operator action following the procedure the reactor temperature is evaluated to 147{sup o} C and the primary circuit pressure to 10 bar. 1 ref., 4 figs., 2 tabs.

Final report of the inter institutional project ININ-CNSNS 'Source Terms specific for the CNLV'; Informe final del proyecto interinstitucional ININ-CNSNS 'Termino Fuente especifico para la CNLV'

Energy Technology Data Exchange (ETDEWEB)

Anaya M, R.A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

1991-02-15

The purpose of the project inter institutional ININ-CNSNS 'Source Terms Specifies for the CNLV' it is the one of implanting in the computer CYBER (CDC 180-830) of the ININ, the 'Source Term Code Package' (STCP) and to make the operation tests and corresponding operation using the data of the sample problem, for finally to liberate the package, all time that by means of the analysis of the results it is consider appropriate. In this report the results of the are presented simulation of the sequence 'Energy Losses external' (Station blackout) and 'Lost total of CA with failure of the RCIC and success of the HPCS' both with data of the Laguna Verde Central. (Author)

Our energies have a future. A future without CO{sub 2}. Areva in 2005; Nos energies ont de l'avenir. Un avenir sans CO{sub 2}. Areva en 2005

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This document is the sustainable development and 2005 annual report altogether of Areva group. It presents first the challenges of energy for economical development, the climate change threat and the sustainability of nuclear power in particular with respect to radioactive wastes management and power blackouts. Then follows a presentation of Areva's 10 commitments for sustainable development (governance and continuous improvement, financial performance, innovation, customer satisfaction, commitment to employees, risk management and prevention, environmental protection, dialogue and consensus building, community involvement). The annual report presents: the 2005 highlights, Areva around the world, key data, corporate governance, organisation of the group, share information and shareholder relations, business review (front end division, reactors and services division, back end division, transmission and distribution division), financial report and glossary. (J.S.)

Our energies have a future. A future without CO2. Areva in 2005

International Nuclear Information System (INIS)

2005-01-01

This document is the sustainable development and 2005 annual report altogether of Areva group. It presents first the challenges of energy for economical development, the climate change threat and the sustainability of nuclear power in particular with respect to radioactive wastes management and power blackouts. Then follows a presentation of Areva's 10 commitments for sustainable development (governance and continuous improvement, financial performance, innovation, customer satisfaction, commitment to employees, risk management and prevention, environmental protection, dialogue and consensus building, community involvement). The annual report presents: the 2005 highlights, Areva around the world, key data, corporate governance, organisation of the group, share information and shareholder relations, business review (front end division, reactors and services division, back end division, transmission and distribution division), financial report and glossary. (J.S.)

What is demand response? Contributing to secure security-of-supply at the electricity markets

International Nuclear Information System (INIS)

Grenaa Jensen, Stine; Skytte, Klaus; Togeby, Mikael

2004-01-01

There is a common understanding that demand response can reduce the total costs of electricity reliability. There has especially been a growing interest in the electricity market where high spot prices in peak periods and blackouts have recently been seen. It is not easy from the existing literature to find a common definition of demands response. Often the term demand response is used broadly without looking at the time dimension. However, it does not make sense to talk about demand response without talking about when, for how long the energy is used or saved, and at which costs. This paper surveys these subjects and set up a systematic grouping of the different characteristics of demand response. It especially looks at the time dimension. (au)

Sizewell 'dirty tricks'

International Nuclear Information System (INIS)

Martin, Steve.

1987-01-01

The pro-nuclear lobby is accused of dubious tactics to promote their case for the Sizewell-B reactor. These include reassessing future electricity demand which, it is claimed, could only be met by nuclear power, claiming that new power stations were needed to avoid blackouts during cold spells, and the reporting of a major design fault in the control rods of the Torness and Heysham AGR stations. The latter is felt to be related to the promotion by the South of Scotland Electricity Board of the AGR case, as opposed to the Central Electricity Generating Board's advocation of a PWR reactor design. The author argues for a series of coal-fired power stations instead, and a major energy conservation programme. (UK)

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

Overview of BWR Severe Accident Sequence Analyses at Oak Ridge National Laboratory

International Nuclear Information System (INIS)

Hodge, S.A.

1983-01-01

Since its inception in October 1980, the Severe Accident Sequence Analysis (SASA) program at Oak Ridge National Laboratory (ORNL) has completed four studies including Station Blackout, Scram Discharge Volume Break, Loss of Decay Heat Removal, and Loss of Injection accident sequences for the Browns Ferry Nuclear Plant. The accident analyses incorporated in a SASA study provide much greater detail than that practically achievable in a Probabilistic Risk Assessment (PRA). When applied to the candidate dominant accident sequences identified by a PRA, the detailed SASA results determine if factors neglected by the PRA would have a significant effect on the order of dominant sequences. Ongoing SASA work at ORNL involves the analysis of Anticipated Transients Without Scram (ATWS) sequences for Browns Ferry

Voltage Stability Control of Electrical Network Using Intelligent Load Shedding Strategy Based on Fuzzy Logic

Directory of Open Access Journals (Sweden)

Houda Jouini

2010-01-01

Full Text Available As a perspective to ensure the power system stability and to avoid the vulnerability leading to the blackouts, several preventive and curative means are adopted. In order to avoid the voltage collapse, load shedding schemes represent a suitable action to maintain the power system service quality and to control its vulnerability. In this paper, we try to propose an intelligent load shedding strategy as a new approach based on fuzzy controllers. This strategy was founded on the calculation of generated power sensitivity degree related to those injected at different network buses. During the fault phase, fuzzy controller algorithms generate monitor vectors ensuring a precalculated load shedding ratio in the purpose to reestablish the power balance and conduct the network to a new steady state.

An important year for Swiss Electricity Politics - President's speech at the shareholder's meeting of the Swiss Association of Electricity Enterprises

International Nuclear Information System (INIS)

Steiner, R.

2004-01-01

This article presents the speech made by Rudolf Steiner, president of the Swiss Association of Electricity Enterprises, in Bad Ragaz in September 2004. Steiner comments on 2004 as being an important year with respect to energy politics in Switzerland. A public vote turned down the idea of opting out of nuclear energy, the Federal Court decided that the Restricted Trade Practices act was also applicable to the Swiss electricity supply industry and the EU parliament passed guidelines on the opening of the European power market. The effects of large-scale blackouts in America and Europe on the public's perception of secure supplies are commented on. The importance of the Association as a provider of services for its members and as a partner for the government is stressed

Intelligent decision support algorithm for distribution system restoration.

Science.gov (United States)

Singh, Reetu; Mehfuz, Shabana; Kumar, Parmod

2016-01-01

Distribution system is the means of revenue for electric utility. It needs to be restored at the earliest if any feeder or complete system is tripped out due to fault or any other cause. Further, uncertainty of the loads, result in variations in the distribution network's parameters. Thus, an intelligent algorithm incorporating hybrid fuzzy-grey relation, which can take into account the uncertainties and compare the sequences is discussed to analyse and restore the distribution system. The simulation studies are carried out to show the utility of the method by ranking the restoration plans for a typical distribution system. This algorithm also meets the smart grid requirements in terms of an automated restoration plan for the partial/full blackout of network.

Isolated grid electron gun and pulser system for long/short pulse operation

International Nuclear Information System (INIS)

Koontz, R.F.; Feathers, L.; Kilbourne, C.; Leger, G.; McKinney, T.

1984-04-01

The new NPI gun at SLAC serves the dual functions of producing long pulse (up to 5 μsec, 180 pps) electron bursts for nuclear physics experiments, and also short (1 nsec) pulses for filling Stanford Synchrotron Radiation Laboratory (SSRL). This is accomplished by means of a newly designed, isolated grid gun, cathode pulsed with a solid state long pulse pulser, and grid pulsed with a fast recharging avalanche type short pulse (1 nsec) grid pulser. The grid pulser is bipolar so that a fast blackout notch can be placed in the long cathode pulse. This fast notch can be seen by Stanford Linear Collider (SLC) instrumentation and allows the long pulse beam to be computer controlled by SLC intensity and beam position monitors

Using MAAP 4.0 to determine risks from steam generator tube leaks or ruptures

International Nuclear Information System (INIS)

Fuller, E.L.; Kenton, M.A.

1996-01-01

As part of the Electric Power Research Institute (EPRI) program on steam generator degradation specific management (SGDSM), the nuclear industry is investigating the effects on plant risk of severe accidents involving steam generator tube leaks or ruptures. Such accidents fall into three classes: those caused by spontaneous, steam generator tube ruptures (SGTRs) that subsequently result in core damage; those caused by design-basis accidents that lead to induced tube ruptures and subsequent core damage; and those that progress to core damage, such as a station blackout (SBO), with subsequent induced tube leakage or rupture. In each case, the potential exists for a significant fraction of the fission products released from a damaged core to reach the environment through the leaking or ruptured tubes

The USGS Geomagnetism Program and its role in Space-Weather Monitoring

Science.gov (United States)

Love, Jeffrey J.; Finn, Carol A.

2011-01-01

Magnetic storms result from the dynamic interaction of the solar wind with the coupled magnetospheric-ionospheric system. Large storms represent a potential hazard for the activities and infrastructure of a modern, technologically based society [Baker et al., 2008]; they can cause the loss of radio communications, reduce the accuracy of global positioning systems, damage satellite electronics and affect satellite operations, increase pipeline corrosion, and induce voltage surges in electric power grids, causing blackouts. So while space weather starts with the Sun and is driven by the solar wind, it is on, or just above, the surface of the Earth that the practical effects of space weather are realized. Therefore, ground-based sensor networks, including magnetic observatories [Love, 2008], play an important role in space weather monitoring.

Integration of electric vehicles with optimum sized storage for grid connected photo-voltaic system

Directory of Open Access Journals (Sweden)

Sulabh Sachan

2017-12-01

Full Text Available The necessity of energy storage by means of battery/EV is exceedingly expected in event of energy blackouts. Different advantages incorporate sparing the cash in purchasing top time power and support the grid when grid power is deficit against the load demand. In this paper, ideal size of energy storage in a grid associated photovoltaic (PV framework is proposed. The methodology of energy flow choice is produced with the appraisal on accessibility of PV yield control and the load demand. The energy flow decision is changed by peak and off peak hours to shorten the functional cost of the grid associated PV framework with storage. Naturally, the quantities of electric vehicles that can be associated are resolved.

An isolated grid electron gun and pulser system for long/short pulse operation

International Nuclear Information System (INIS)

Koontz, R.F.; Feathers, L.; Kilbourne, C.; Leger, G.; McKinney, T.

1984-01-01

The new NPI gun at SLAC serves the dual functions of producing long pulse (up to 5 μsec, 180 pps) electron bursts for nuclear physics experiments, and also short ( 1 nsec) pulses for filling Stanford Synchrotron Radiation Laboratory (SSRL). This is accomplished by means of a newly designed, isolated grid gun, cathode pulsed with a solid state long pulse pulser, and grid pulsed with a fast recharging avalanche type short pulse (1 nsec) grid pulser. The grid pulser is bipolar so that a fast blackout notch can be placed in the long cathode pulse. This fast notch can be seen by Stanford Linear Collider (SLC) instrumentation and allows the long pulse beam to be computer controlled by SLC intensity and beam position monitors. (orig.)

The construction of power grid operation index system considering the risk of maintenance

Science.gov (United States)

Tang, Jihong; Wang, Canlin; Jiang, Xinfan; Ye, Jianhui; Pan, Feilai

2018-02-01

In recent years, large-scale blackout occurred at home and abroad caused widespread concern about the operation of the grid in the world, and the maintenance risk is an important indicator of grid safety. The barrier operation of the circuit breaker exists in the process of overhaul of the power grid. The operation of the different barrier is of great significance to the change of the power flow, thus affecting the safe operation of the system. Most of the grid operating status evaluation index system did not consider the risk of maintenance, to this end, this paper from the security, economy, quality and cleanliness of the four angles, build the power grid operation index system considering the risk of maintenance.

Solving the maintenance dilemma of ageing controls in nuclear standby generators. The decision to retro-fit the control system with 'off the shelf technology'

International Nuclear Information System (INIS)

Jackson, Neil; Rees, Christpher; Yeremain, Joseph

2010-01-01

Blackouts - Are we 2 Steps away from Nuclear meltdown owing to Aging Controls? The intent of this white paper is to high-light the need to:- 1. Replace the aging control systems associated with critical safety equipment of Standby Generators in the nuclear environment. 2. Explain how 'off the shelf' standard control equipment may be suitably selected, integrated and tested for a nuclear environment. 3. High-light the lessons learned in respect of: - a. Qualification of COTS (commercial off the shelf) equipment for use in a nuclear application. b. Software quality assurance program. c. Reducing plant outage time. 4. Guide you on the selection criteria of credible partners that can implement such mission critical control systems. Causes for Concern - The control systems of some of the Standby Generators are 30+ years old and aging equipment is no longer available from the OEM's. Maintenance crews are evolving with young engineers who have no experience, or chance to be trained, on the old installed control base. The writer has no doubt that the extent of the black outs of North America, Aug 2003, and the standby generators ever reducing availability, has compromised their ability to provide essential service and communications to maintain the safety of the nuclear plant. These concerns prompted Ontario Power Generator and Bruce Power to review the reliability of their standby generators and this review prompted them to locate a suitable supplier for the task of replacing the control system. OPG's previous attempts to have the controls replaced by I and C dedicated companies weighed heavy on their minds. Worsening the dilemma was the fact that it used dedicated controls and what might be considered 'Propriety Software'. Black Outs - Not only is it possible, the probability of it happening is getting stronger The Northeast Blackout of 2003 was a massive widespread power outage that occurred throughout parts of the North-eastern and Midwestern United States and Ontario

Solving the maintenance dilemma of ageing controls in nuclear standby generators. The decision to retro-fit the control system with 'off the shelf technology'

Energy Technology Data Exchange (ETDEWEB)

Jackson, Neil [Turbine Controls Ltd Canada, 5288 General Rd, L4W 1Z8 Mississauga (Canada); Rees, Christpher [Turbine Controls Ltd UK, 52 Kenilworth Drive, LE2 5LG Leicester (United Kingdom); Yeremain, Joseph [Thermodyne, 421 Nugget Avenue Unit 3, Toronto Ontario M1S 4L8 (Canada)

2010-07-01

Blackouts - Are we 2 Steps away from Nuclear meltdown owing to Aging Controls? The intent of this white paper is to high-light the need to:- 1. Replace the aging control systems associated with critical safety equipment of Standby Generators in the nuclear environment. 2. Explain how 'off the shelf' standard control equipment may be suitably selected, integrated and tested for a nuclear environment. 3. High-light the lessons learned in respect of: - a. Qualification of COTS (commercial off the shelf) equipment for use in a nuclear application. b. Software quality assurance program. c. Reducing plant outage time. 4. Guide you on the selection criteria of credible partners that can implement such mission critical control systems. Causes for Concern - The control systems of some of the Standby Generators are 30+ years old and aging equipment is no longer available from the OEM's. Maintenance crews are evolving with young engineers who have no experience, or chance to be trained, on the old installed control base. The writer has no doubt that the extent of the black outs of North America, Aug 2003, and the standby generators ever reducing availability, has compromised their ability to provide essential service and communications to maintain the safety of the nuclear plant. These concerns prompted Ontario Power Generator and Bruce Power to review the reliability of their standby generators and this review prompted them to locate a suitable supplier for the task of replacing the control system. OPG's previous attempts to have the controls replaced by I and C dedicated companies weighed heavy on their minds. Worsening the dilemma was the fact that it used dedicated controls and what might be considered 'Propriety Software'. Black Outs - Not only is it possible, the probability of it happening is getting stronger The Northeast Blackout of 2003 was a massive widespread power outage that occurred throughout parts of the North-eastern and

Characteristics of debris in the lower head of a BWR in different severe accident scenarios

International Nuclear Information System (INIS)

Phung, Viet-Anh; Galushin, Sergey; Raub, Sebastian; Goronovski, Andrei; Villanueva, Walter; Kööp, Kaspar; Grishchenko, Dmitry; Kudinov, Pavel

2016-01-01

Highlights: • Station blackout scenario with delayed recovery of safety systems in a Nordic BWR is considered. • Genetic algorithm and random sampling methods are used to explore accident scenario domain. • Main groups of scenarios are identified. • Ranges and distributions of characteristics of debris bed in the lower head are determined. - Abstract: Nordic boiling water reactors (BWRs) adopt ex-vessel debris cooling to terminate severe accident progression. Core melt released from the vessel into a deep pool of water is expected to fragment and form a coolable debris bed. Characteristics of corium melt ejection from the vessel determine conditions for molten fuel–coolant interactions (FCI) and debris bed formation. Non-coolable debris bed or steam explosion can threaten containment integrity. Vessel failure and melt ejection mode are determined by the in-vessel accident progression. Characteristics (such as mass, composition, thermal properties, timing of relocation, and decay heat) of the debris bed formed in the process of core relocation into the vessel lower plenum define conditions for the debris reheating, remelting, melt-vessel structure interactions, vessel failure and melt release. Thus core degradation and relocation are important sources of uncertainty for the success of the ex-vessel accident mitigation strategy. The goal of this work is improve understanding how accident scenario parameters, such as timing of failure and recovery of different safety systems can affect characteristics of the debris in the lower plenum. Station blackout scenario with delayed power recovery in a Nordic BWR is considered using MELCOR code. The recovery timing and capacity of safety systems were varied using genetic algorithm (GA) and random sampling methods to identify two main groups of scenarios: with relatively small ( 100 tons) amount of relocated debris. The domains are separated by the transition regions, in which relatively small variations of the input

The extra-atmospheric masses of small meteoric fireballs from the Prairie and the Canadian camera networks.

Science.gov (United States)

Popelenskaya, N.

2007-08-01

Existing methods of definition of extra-atmospheric masses of small meteoric bodies according to supervision of their movement in an atmosphere contain the certain arbitrariness. Vigorous attempts to overcome a divergence of results of calculations on the basis of various approaches often lead to physically incorrect conclusions. The output consists in patient accumulation of estimations and calculations for gradual elimination uncertainties. The equations of meteoric physics include two dimensionless parameters - factor ablation ? and factor of braking ?. In work are cited the data processing supervision of small meteors Prairie and Canadian networks, by a finding of values of parameters ? and ? with use of a method of the least squares. Also values of heights blackout a meteor which turn out from conditions of full destruction or final braking with use of the received values of ? and ? are considered. In prevailing number of supervision for considered meteors braking is insignificant. Results of calculations of height of blackout meteors confirm suitability of the approximations used in work for the description of movement of small meteors. In work results of calculation of extra-atmospheric masses with use of factor of braking for meteoric bodies of the spherical form with density of an ice and a stone are presented. On the basis of the received results discrepancy of photometric masses to values of masses of the input, received on observable braking proves to be true. In most cases received magnitude of masses essentially less photometric masses. Processing of supervision of small meteors Prairie and Canadian camera networks has shown, that the so-called photometric mass mismatches values of mass of the input, defined on observable braking. Acceptance of photometric value as the mass defining braking of a body, leads to obviously underestimated values of density of substance meteoric body. The further researches on specification of interpretation of supervision

Application of FFTBM with signal mirroring to improve accuracy assessment of MELCOR code

International Nuclear Information System (INIS)

Saghafi, Mahdi; Ghofrani, Mohammad Bagher; D’Auria, Francesco

2016-01-01

Highlights: • FFTBM-SM is an improved Fast Fourier Transform Base Method by signal mirroring. • FFTBM-SM has been applied to accuracy assessment of MELCOR code predictions. • The case studied was Station Black-Out accident in PSB-VVER integral test facility. • FFTBM-SM eliminates fluctuations of accuracy indices when signals sharply change. • Accuracy assessment is performed in a more realistic and consistent way by FFTBM-SM. - Abstract: This paper deals with the application of Fast Fourier Transform Base Method (FFTBM) with signal mirroring (FFTBM-SM) to assess accuracy of MELCOR code. This provides deeper insights into how the accuracy of MELCOR code in predictions of thermal-hydraulic parameters varies during transients. The case studied was modeling of Station Black-Out (SBO) accident in PSB-VVER integral test facility by MELCOR code. The accuracy of this thermal-hydraulic modeling was previously quantified using original FFTBM in a few number of time-intervals, based on phenomenological windows of SBO accident. Accuracy indices calculated by original FFTBM in a series of time-intervals unreasonably fluctuate when the investigated signals sharply increase or decrease. In the current study, accuracy of MELCOR code is quantified using FFTBM-SM in a series of increasing time-intervals, and the results are compared to those with original FFTBM. Also, differences between the accuracy indices of original FFTBM and FFTBM-SM are investigated and correction factors calculated to eliminate unphysical effects in original FFTBM. The main findings are: (1) replacing limited number of phenomena-based time-intervals by a series of increasing time-intervals provides deeper insights about accuracy variation of the MELCOR calculations, and (2) application of FFTBM-SM for accuracy evaluation of the MELCOR predictions, provides more reliable results than original FFTBM by eliminating the fluctuations of accuracy indices when experimental signals sharply increase or

Solar energy estimated from geostationary satellites and its application on the energy management system

Science.gov (United States)

Nakajima, T. Y.; Takamatsu, T.; Funayama, T.; Yamamoto, Y.; Takenaka, H.; Nakajima, T.; Irie, H.; Higuchi, A.

2017-12-01

Recently, estimating and forecasting the solar radiation in terms of the electric power generation by photovoltaic (PV) systems is needed for the energy management system (EMS). The estimation technique depends on the latest atmospheric sciences. For instance, when one like to estimate solar radiation reached to ground surface, one will focus on the existence of clouds and their properties, because clouds exert an important influence to the radiative transfer. Visible-to-infared imaging radiometer aboard the geostationary satellites, Himawari, GOES, and Meteosat are useful for such objective, since they observe clouds for full disk of the Earth with high temporal frequency and moderately spatial resolution. Estimation of solar radiation at the ground surface from satellite imagery consists of two steps. The first step is retrieval of cloud optical and microphysical properties by use of the multispectral imaging data. Indeed, we retrieve cloud optical thickness, cloud particle sizes, and cloud top height from visible, near-infrared, and thermal infrared wavelength of the satellite imageries, respectively. The second step is the radiative transfer calculation. We will obtain solar radiation reached to the ground surface, using cloud properties retrieved from the first step, and radiative transfer calculations. We have built a system for near-real time estimation of solar radiation for global scale, named the AMATERASS system, under the support of JST (Japan Science and Technology Agency), CREST/EMS (Energy Management System). The AMATERASS dataset has been used for several researches. For example, Waseda University group applied the AMATERASS data in the electric power system, considering accidental blackout in the electric system for local scale. They made it clear that when AMATERASS data exists the chance of electric voltage deviancy is mitigated when the blackout is over. We have supported a solar car race in Australia, named World Solar Challenge (WSC) 2013

Characteristics of debris in the lower head of a BWR in different severe accident scenarios

Energy Technology Data Exchange (ETDEWEB)

Phung, Viet-Anh, E-mail: vaphung@kth.se; Galushin, Sergey, E-mail: galushin@kth.se; Raub, Sebastian, E-mail: raub@kth.se; Goronovski, Andrei, E-mail: andreig@kth.se; Villanueva, Walter, E-mail: walterv@kth.se; Kööp, Kaspar, E-mail: kaspar@safety.sci.kth.se; Grishchenko, Dmitry, E-mail: dmitry@safety.sci.kth.se; Kudinov, Pavel, E-mail: pavel@safety.sci.kth.se

2016-08-15

Highlights: • Station blackout scenario with delayed recovery of safety systems in a Nordic BWR is considered. • Genetic algorithm and random sampling methods are used to explore accident scenario domain. • Main groups of scenarios are identified. • Ranges and distributions of characteristics of debris bed in the lower head are determined. - Abstract: Nordic boiling water reactors (BWRs) adopt ex-vessel debris cooling to terminate severe accident progression. Core melt released from the vessel into a deep pool of water is expected to fragment and form a coolable debris bed. Characteristics of corium melt ejection from the vessel determine conditions for molten fuel–coolant interactions (FCI) and debris bed formation. Non-coolable debris bed or steam explosion can threaten containment integrity. Vessel failure and melt ejection mode are determined by the in-vessel accident progression. Characteristics (such as mass, composition, thermal properties, timing of relocation, and decay heat) of the debris bed formed in the process of core relocation into the vessel lower plenum define conditions for the debris reheating, remelting, melt-vessel structure interactions, vessel failure and melt release. Thus core degradation and relocation are important sources of uncertainty for the success of the ex-vessel accident mitigation strategy. The goal of this work is improve understanding how accident scenario parameters, such as timing of failure and recovery of different safety systems can affect characteristics of the debris in the lower plenum. Station blackout scenario with delayed power recovery in a Nordic BWR is considered using MELCOR code. The recovery timing and capacity of safety systems were varied using genetic algorithm (GA) and random sampling methods to identify two main groups of scenarios: with relatively small (<20 tons) and large (>100 tons) amount of relocated debris. The domains are separated by the transition regions, in which relatively small

Application of FFTBM with signal mirroring to improve accuracy assessment of MELCOR code

Energy Technology Data Exchange (ETDEWEB)

Saghafi, Mahdi [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); Ghofrani, Mohammad Bagher, E-mail: ghofrani@sharif.edu [Department of Energy Engineering, Sharif University of Technology, Azadi Avenue, Tehran (Iran, Islamic Republic of); D’Auria, Francesco [San Piero a Grado Nuclear Research Group (GRNSPG), University of Pisa, Via Livornese 1291, San Piero a Grado, Pisa (Italy)

2016-11-15

Highlights: • FFTBM-SM is an improved Fast Fourier Transform Base Method by signal mirroring. • FFTBM-SM has been applied to accuracy assessment of MELCOR code predictions. • The case studied was Station Black-Out accident in PSB-VVER integral test facility. • FFTBM-SM eliminates fluctuations of accuracy indices when signals sharply change. • Accuracy assessment is performed in a more realistic and consistent way by FFTBM-SM. - Abstract: This paper deals with the application of Fast Fourier Transform Base Method (FFTBM) with signal mirroring (FFTBM-SM) to assess accuracy of MELCOR code. This provides deeper insights into how the accuracy of MELCOR code in predictions of thermal-hydraulic parameters varies during transients. The case studied was modeling of Station Black-Out (SBO) accident in PSB-VVER integral test facility by MELCOR code. The accuracy of this thermal-hydraulic modeling was previously quantified using original FFTBM in a few number of time-intervals, based on phenomenological windows of SBO accident. Accuracy indices calculated by original FFTBM in a series of time-intervals unreasonably fluctuate when the investigated signals sharply increase or decrease. In the current study, accuracy of MELCOR code is quantified using FFTBM-SM in a series of increasing time-intervals, and the results are compared to those with original FFTBM. Also, differences between the accuracy indices of original FFTBM and FFTBM-SM are investigated and correction factors calculated to eliminate unphysical effects in original FFTBM. The main findings are: (1) replacing limited number of phenomena-based time-intervals by a series of increasing time-intervals provides deeper insights about accuracy variation of the MELCOR calculations, and (2) application of FFTBM-SM for accuracy evaluation of the MELCOR predictions, provides more reliable results than original FFTBM by eliminating the fluctuations of accuracy indices when experimental signals sharply increase or

Feasibility study of cocos, condensation of containment atmosphere on structures

International Nuclear Information System (INIS)

Rij, H.M. van; Vonka, V.

1989-12-01

The aim of this report is to assess the state of the art of the knowledge of the thermo-hydraulic conditions within a LWR containment in order to determine both the radioactive and the non-radioactive aerosol deposition rates during a severe reactor accident. The radioactive aerosol in the containment atmosphere is, together with the noble gases, responsible for the radioactive source term into the biosphere when a containment failure occurs. The dominant aerosol removal mechanisms depend strongly upon the thermal-hydraulic state of the containment atmosphere. It is demonstrated that the thermohydraulic state, determined by heat sources and the sensible heat transport, is predominantly super-heated when fission products are released into the containment. Hence the thermohydraulic conditions are not favorable for an intensive bulk condensation onto aerosol particles during an essential period of time. A station black-out scenario, in which the primary system of the considered 500 MWe PWR with a dry cavity is depressurized prior to vessel failure, is used as an example to demonstrate this effect. The results, obtained with the CONTAIN code, show the relevance of the sensible heat transport in the period of time (c.a. 30 minutes) between the end of the injection of the steam and fission products into the containment, and the molten core concrete interaction. All considered variation of the station black-out scenario, in which the decay heat dissipated in the containment atmosphere has been 10% of the total decay heat, indicate that the atmosphere becomes super-heated within the 30 minutes. Reducing the fraction of the decay heat in the containment from the 10% to 5% increases the time period with saturated conditions. The amount of the decay heat released into the containment atmosphere forms the major factor determining the thermohydraulic state. It influences the duration of the bulk condensation period, which in turn has an influence on the aerosol deposition

Vulnerability of steam generator super-emergency feeding. Super-emergency feedwater system for the Mochovce NPP steam-generators

International Nuclear Information System (INIS)

Hlasova, M.; Jary, A.

1997-01-01

The following major requirements and criteria fulfillment concerned the super-emergency feedwater system (SEFW) system were proposed: to provide sufficient water amount for accident conditions, inclusive seismicity, even during required SEFW system operation for the time period of 72 hours; to analyse ensuring of residual heat removal in case of a station black-out; to state criteria for water supply by the SEFW system into the steam generators (SGs); to simplify the existing connection scheme inclusive decreasing the number of valves, which are in series; to analyse and provide the system protection against a common cause failure, which the SEFW system did not provide in some parts (possibilities of three systems failure due to flooding; vulnerability of all tanks by the operation building fall in case of a seismic event; vulnerability of all tanks due to extreme climatic conditions; vulnerability of all tanks during new seismic loading and consequent mutual endangering; the possibility of three systems failure due to common routing in the vicinity of high; energy media on the +14,7 m floor in the intermediate machinery building and due to inconsistent electrical valves secured power supply systems); to analyse temperature increase impact on the number of uses and lifetime of SGs; to perform a change of SEFW system pipelines routing layout outside the dangerous area of the +14,7 m floor in the intermediate machinery building with high energy media; checking the thanks autonomy. There were performed analyses of selected transient operation modes. The analyses had the following objectives: necessary flowrate of the SEFW in case of the primary side stabilised temperature of 140 C till 72 hours of the process duration; sufficient capacity of one subsystem for the supply of sufficient water amount; sufficient water reserve in the tanks at given conditions; and other. Accident situations were evaluated using an analysis and three characteristic operation modes were

Design and transient analyses of emergency passive residual heat removal system of CPR1000

International Nuclear Information System (INIS)

Zhang, Y.P.; Qiu, S.Z.; Su, G.H.; Tian, W.X.

2012-01-01

Highlights: ► Designing an EPRHRs for CPR1000. ► Developing a RELAP model of the EPRHRs. ► The EPRHRs could take away the decay heat effectively. - Abstract: The steam generator secondary emergency passive residual heat removal system (EPRHRs) is a new design for traditional generation II + reactor CPR1000. The EPRHRs is designed to improve the safety and reliability of CPR1000 by completely or partially replacing traditional emergency water cooling system in the event of the station blackout or loss of heat sink accident. The EPRHRs consists of steam generator (SG), heat exchanger (HX), emergency makeup tank (EMT), cooling water tank (CWT), and corresponding pipes and valves. In order to improve the safety and reliability of CPR1000, the model of the primary loop and the EPRHRs was developed to investigate residual heat removal capability of the EPRHRs and the transient characteristics of the primary loop affected by the EPRHRs using RELAP5/MOD3.4. The transient characteristics of the primary loop and the EPRHRs were calculated in the event of station blackout accident. Sensitivity studies of the EPRHRs were also conducted to investigate the response of the primary loop and the EPRHRs on the main parameters of the EPRHRs. The EPRHRs could supply water to the SG shell side from the EMT successfully. The calculation results showed that the EPRHRs could take away the decay heat from the primary loop effectively, and that the single-phase and two-phase natural circulations were established in the primary loop and EPRHRs loop, respectively. The results also indicated that the effect of isolation valve open time on the transient characteristics of the primary loop was little. However, the effect of isolation valve open time on the EPRHRs condensate flow was relatively greater. The isolation valves should not be opened too rapidly during the isolation valve opening process, and the isolation valve opening time should be greater than 10 s, which could avoid the

Online scenario labeling using a hidden Markov model for assessment of nuclear plant state

International Nuclear Information System (INIS)

Zamalieva, Daniya; Yilmaz, Alper; Aldemir, Tunc

2013-01-01

By taking into account both aleatory and epistemic uncertainties within the same probabilistic framework, dynamic event trees (DETs) provide more comprehensive and systematic coverage of possible scenarios following an initiating event compared to conventional event trees. When DET generation algorithms are applied to complex realistic systems, extremely large amounts of data can be produced due to both the large number of scenarios generated following a single initiating event and the large number of data channels that represent these scenarios. In addition, the computational time required for the simulation of each scenario can be very large (e.g. about 24 h of serial run simulation time for a 4 h station blackout scenario). Since scenarios leading to system failure are more of interest, a method is proposed for online labeling of scenarios as failure or non-failure. The algorithm first trains a Hidden Markov Model, which represents the behavior of non-failure scenarios, using a training set from previous simulations. Then, the maximum likelihoods of sample failure and non-failure scenarios fitting this model are computed. These values are used to determine the timestamp at which the labeling of a certain scenario should be performed. Finally, during the succeeding timestamps, the likelihood of each scenario fitting the learned model is computed, and a dynamic thresholding based on the previously calculated likelihood values is applied. The scenarios whose likelihood is higher than the threshold are labeled as non-failure. The proposed algorithm can further delay the non-failure scenarios or discontinue them in order to redirect the computational resources toward the failure scenarios, and reduce computational time and complexity. Experiments using RELAP5/3D model of a fast reactor utilizing an Reactor Vessel Auxiliary Cooling System (RVACS) passive decay heat removal system and dynamic analysis of a station blackout (SBO) event show that the proposed method is

Analysis of safety impacts from external flooding using the risk-informed safety margin characterization (RISMC) Toolkit

International Nuclear Information System (INIS)

Smith, Curtis L.; Mandelli, Diego; Prescott, Steve

2015-01-01

The existing fleet of U.S. nuclear power plants is in the process of extending its lifetime and increasing the power generated from these plants via power uprates. In order to evaluate the impact of these factors on the safety of the plant, the Risk-Informed Safety Margin Characterization (RISMC) project aims to provide insight to decision makers through a series of simulations of the plant dynamics for different initial conditions (e.g., probabilistic analysis and uncertainty quantification). This paper demonstrates how Idaho National Laboratory (INL) researchers use the RISMC Toolkit to investigate complex nuclear plant phenomena using RAVEN and RELAP-7. The analysis focused on a highly relevant topic currently facing some nuclear power plants – specifically flooding issues. This research and development looked at challenges to a hypothetical pressurized water reactor, including: (1) a potential loss of off-site power followed by the possible loss of all diesel generators (i.e., a station black-out event), (2) earthquake induced station-blackout, and (3) a potential earthquake induced tsunami flood. The analysis is performed by using a set of codes: a thermal-hydraulic code (RELAP-7), a flooding simulation tool (NEUTRINO) and a stochastic analysis tool (RAVEN) – these are currently under development at INL. Using RAVEN, we were able to perform multiple RELAP-7 simulation runs by changing specific parts of the model in order to reflect specific aspects of different scenarios, including both the failure and recovery of critical components. The simulation employed traditional statistical tools (such as Monte-Carlo sampling) and more advanced machine-learning based algorithms to perform uncertainty quantification in order to understand changes in system performance and limitations as a consequence of power uprate. Qualitative and quantitative results obtained gave a detailed picture of the issues associated with potential accident scenarios. These types of

Exchange of pressurizer safeguarding system at Biblis nuclear power station

International Nuclear Information System (INIS)

Weber, D.; Hofbeck, W.

1991-01-01

Valves and piping of the pressurizer safeguarding system are exchanged and reset in such a way that they are suitable not only for discharging steam, but also for discharging a water-steam mixture and hot pressurized water; for the emergency measure of primary depressurization by hand (bleed) in the event of failure of the entire feedwater supply and station black-out, and in the event of operational transients with supposed failure of the reactor scram (ATWS). To achieve this, in addition to the requirements of the pressurizer discharging station, changes have to be made to the valve drive to dominate the water loads. During the 1990 inspection this exchange of the pressurizer discharging station was performed at the Biblis A unit as the first German plant. (orig.) [de

Mr Minister, do not cherish illusions, passing from 75 to 50 pc of nuclear energy will result in the stoppage of very few reactors and will cost a lot

International Nuclear Information System (INIS)

Nifenecker, Herve

2017-01-01

After a brief recall of the situation of the French energy mix in 2015, the author discusses the consequences of a reduction of the nuclear share from 75 pc to 50 pc. He outlines that using fossil energies to counterbalance this evolution would result in an important increase of carbon emissions which is in contradiction with France commitments according to the COP21 agreement. He shows that the use of renewable energies (wind and solar) to replace this share of nuclear energy raises problems due to the intermittent character of these energies, and could result in black-outs when facing winter peaks (data related to wind and nuclear daily productions in December 2016 are used as illustration). The author also gives an assessment of costs associated with such a reduction of nuclear share

Frequency Control Strategy for Black Starts via PMSG-Based Wind Power Generation

Directory of Open Access Journals (Sweden)

Yi Tang

2017-03-01

Full Text Available The use of wind power generation (WPG as a source for black starts will significantly enhance the resiliency of power systems and shorten their recovery time from blackouts. Given that frequency stability is the most serious issue during the initial recovery period, virtual inertia control can enable wind turbines to provide frequency support to an external system. In this study, a general procedure of WPG participating in black starts is presented, and the key issues are discussed. The adaptability of existing virtual inertia control strategies is analyzed, and improvement work is performed. A new coordinated frequency control strategy is proposed based on the presented improvement work. A local power network with a permanent-magnet synchronous generator (PMSG-based wind farm is modeled and used to verify the effectiveness of the strategy.

SOSPO-SP: Secure Operation of Sustainable Power Systems Simulation Platform for Real-Time System State Evaluation and Control

DEFF Research Database (Denmark)

Morais, Hugo; Vancraeyveld, Pieter; Pedersen, Allan Henning Birger

2014-01-01

Measurement Units (PMUs) provides more information and enables wide-area monitoring with accurate timing. One of the challenges in the near future is converting the high quantity and quality of information provided by PMUs into useful knowledge about operational state of a global system. The use of real-time...... simulation in closed-loop is essential to develop and validate new real-time applications of wide-area PMU data. This paper presents a simulation platform developed within the research project Secure Operation of Sustainable Power Systems (SOSPO). The SOSPO simulation platform (SOSPO-SP) functions...... in a closed-loop, integrating new real-time assessment methods to provide useful information to operators in power system control centers and to develop new control methodologies that handle emergency situations and avoid power system blackouts....

Accident sequences simulated at the Juragua nuclear power plant

International Nuclear Information System (INIS)

Carbajo, J.J.

1998-01-01

Different hypothetical accident sequences have been simulated at Unit 1 of the Juragua nuclear power plant in Cuba, a plant with two VVER-440 V213 units under construction. The computer code MELCOR was employed for these simulations. The sequences simulated are: (1) a design-basis accident (DBA) large loss of coolant accident (LOCA) with the emergency core coolant system (ECCS) on, (2) a station blackout (SBO), (3) a small LOCA (SLOCA) concurrent with SBO, (4) a large LOCA (LLOCA) concurrent with SBO, and (5) a LLOCA concurrent with SBO and with the containment breached at time zero. Timings of important events and source term releases have been calculated for the different sequences analyzed. Under certain weather conditions, the fission products released from the severe accident sequences may travel to southern Florida

Our energies have a future. A future without CO{sub 2}. Areva in 2005; Nos energies ont de l'avenir. Un avenir sans CO{sub 2}. Areva en 2005

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This document is the sustainable development and 2005 annual report altogether of Areva group. It presents first the challenges of energy for economical development, the climate change threat and the sustainability of nuclear power in particular with respect to radioactive wastes management and power blackouts. Then follows a presentation of Areva's 10 commitments for sustainable development (governance and continuous improvement, financial performance, innovation, customer satisfaction, commitment to employees, risk management and prevention, environmental protection, dialogue and consensus building, community involvement). The annual report presents: the 2005 highlights, Areva around the world, key data, corporate governance, organisation of the group, share information and shareholder relations, business review (front end division, reactors and services division, back end division, transmission and distribution division), financial report and glossary. (J.S.)

Multiagent System-Based Wide-Area Protection and Control Scheme against Cascading Events

DEFF Research Database (Denmark)

Liu, Zhou; Chen, Zhe; Sun, Haishun

2015-01-01

In this paper, a multi agent system (MAS) based wide area protection and control scheme is proposed to deal with the long term voltage instability induced cascading trips. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal emergency control...... strategy is defined to adjust the emergency states timely and prevent the unexpected relay trips. In order to supervise the control process and further minimize the load loss, an agent based process control is adopted to monitor the states of distributed controllers and adjust the emergency control...... strategy. A hybrid simulation platform based on LabVIEW and real time digital simulator (RTDS) is set up to simulate a blackout case in the power system of Eastern Denmark and to demonstrate the effectiveness of the proposed MAS based protection strategy....

Selectivity of power system protections at power swings in power system

Directory of Open Access Journals (Sweden)

Jan Machowski

2012-12-01

Full Text Available The paper discusses out-of-step protection systems such as: generator pole slip protections, out of step tripping protections, distance protections of step-up transformer, distance protections of transmission lines and transformers, power swing blocking, and special out-of-step protection. It is shown that all these protections make up a protection system, to which a setting concept uniform for the entire power system has to be applied. If a power system is inappropriately equipped with these protections, or their settings are inappropriate, they may operate unselectively, thus contributing to the development of power system blackouts. In the paper the concepts for a real power system are given for the two stages: target stage fully compliant with selectivity criteria, and transitional stage between the current and target stages.

Millimeter wave and terahertz wave transmission characteristics in plasma

International Nuclear Information System (INIS)

Ma Ping; Qin Long; Chen Weijun; Zhao Qing; Shi Anhua; Huang Jie

2013-01-01

An experiment was conducted on the shock tube to explore the transmission characteristics of millimeter wave and terahertz wave in high density plasmas, in order to meet the communication requirement of hypersonic vehicles during blackout. The transmission attenuation curves of millimeter wave and terahertz wave in different electron density and collision frequency were obtained. The experiment was also simulated by auxiliary differential equation finite-difference time-domain (ADE-FDTD) methods. The experimental and numerical results show that the transmission attenuation of terahertz wave in the plasma is smaller than that of millimeter wave under the same conditions. The transmission attenuation of terahertz wave in the plasma is enhanced with the increase of electron density. The terahertz wave is a promising alternative to the electromagnetic wave propagation in high density plasmas. (authors)

Study on risk factors of PWR accidents beyond design basis

International Nuclear Information System (INIS)

Ahn, Seung Hoon; Nah, W. J.; Bang, Y. S.; Oh, D. Y.; Oh, S. H.

2005-01-01

Development of the regulatory guidelines for Beyond Design Basis Accidents (BDBA) with high risk requires a detailed investigation of major factors contributing to the event risk. In this study, each event was classified by the level of risk, based on the probabilistic safety assessment results, so that BDBA with high risk could be selected, with consideration of foreign and domestic regulations, and operating experiences. The regulatory requirements and technical backgrounds for the selected accidents were investigated, and effective regulatory approaches for risk reduction of the accidents. The following conclusions were drawn from this study: - Selected high risk BDBA is station blackout, anticipated without scram, total loss of feedwater. - Major contributors to the risk of selected events were investigated, and appropriate assessment of them was recommended for development of the regulatory guidelines

Saving electricity in a hurry - update 2011

Energy Technology Data Exchange (ETDEWEB)

Pasquier, Sara Bryan

2011-06-15

As demonstrated by the March 2011 earthquake and tsunami-triggered blackouts in Japan, electricity shortfalls can happen anytime and anywhere. Countries can minimise the negative economic, social and environmental impacts of such electricity shortfalls by developing emergency energy-saving strategies before a crisis occurs. This new IEA report highlights preliminary findings and conclusions from electricity shortfalls in Japan, the United States, New Zealand, South Africa and Chile. It draws on recent analysis to: reinforce well-established guidelines on diagnosing electricity shortfalls, identifying energy-saving opportunities and selecting a package of energy-saving measures; and highlight proven practice for implementing emergency energy-saving programmes. This paper will be valuable to government, academic, private-sector and civil-society stakeholders who inform, develop and implement electricity policy in general, and emergency energy-saving programmes in particular.

Economic demand response model in liberalised electricity markets with respect to flexibility of consumers

DEFF Research Database (Denmark)

Sharifi, Reza; Anvari-Moghaddam, Amjad; Fathi, S. Hamid

2017-01-01

Before restructuring in the electricity industry, the primary decision-makers of the electricity market were deemed to be power generation and transmission companies, market regulation boards, and power industry regulators. In this traditional structure, consumers were interested in receiving...... electricity at flat rates while paying no attention to the problems of this industry. This attitude was the source of many problems, sometimes leading to collapse of power systems and widespread blackouts. Restructuring of the electricity industry however provided a multitude of solutions to these problems....... The most important solution can be demand response (DR) programs. This paper proposes an economic DR model for residential consumers in liberalized electricity markets to change their consumption pattern from times of high energy prices to other times to maximize their utility functions. This economic...

Analysis of induced steam generator tube rupture using MAAP 4.0

International Nuclear Information System (INIS)

Kenton, M.; Epstein, M.; Henry, R.E.; Paik, C.; Fuller, E.

1996-01-01

The nuclear industry has initiated a program of Steam Generator Degradation Specific Management (SGDSM) to cope with the various types of corrosion that have been observed in pressurized water reactor (PWR) steam generators. In parallel, the U.S. Nuclear Regulatory Commission is promulgating revised rules on steam generator tube integrity. To support these efforts, the Electric Power Research Institute has sponsored calculations with the MAAP 4 code. The principal objective of these calculations is to estimate the peak temperatures experienced by the steam generator tubes during high-pressure severe accidents. These results are used to evaluate the potential for degraded tubes to leak or rupture. Attention was focused on station blackout (SBO) accidents with loss of turbine-driven auxiliary feedwater because these generally result in the greatest threat to the tubes

A MARS and MIDAS Linked Accident Simulation for Large LOCA in APR1400

International Nuclear Information System (INIS)

Choi, Young; Kim, K. R.; Kim, D. H.; Chung, B. D.

2006-01-01

A linked calculation utilizing the design-basis code MARS and the severe accident code MIDAS has been accomplished for a station blackout simulation in APR1400. The MARS code was developed by using the RELAP3/MOD3 and COBRA-TF codes, while the MIDAS code is currently under a development process using the MELCOR code. The objectives of this paper are to explain how to identify the MAR-MIDAS linked calculation outlines and the technical problems, including the MARS data transfer method, the MIDAS input generation works and so on. For the performance verification of the MARS-MIDAS linked calculation, the MARS, MIDAS and their linkage system are run independently for the same initiating event, so that their data can be compared with each other after the selection of proper variables

Reactor-core isolation cooling system with dedicated generator

International Nuclear Information System (INIS)

Nazareno, E.V.; Dillmann, C.W.

1992-01-01

This patent describes a nuclear reactor complex. It comprises a dual-phase nuclear reactor; a main turbine for converting phase-conversion energy stored by vapor into mechanical energy for driving a generator; a main generator for converting the mechanical energy into electricity; a fluid reservoir external to the reactor; a reactor core isolation cooling system with several components at least some of which require electrical power. It also comprises an auxiliary pump for pumping fluid from the reservoir into the reactor pressure vessel; an auxiliary turbine for driving the pump; control means for regulating the rotation rate of the auxiliary turbine; cooling means for cooling the control means; and an auxiliary generator coupled to the auxiliary turbine for providing at least a portion of the electrical power required by the components during a blackout condition

Power Struggle: Changing Momentum in the Restructured American Electric Utility System

International Nuclear Information System (INIS)

Hirsh, Richard F.

2004-01-01

Since the 1970's, producing and distributing electricity were considered as a natural monopoly. They were subjected to state regulation meant to defend the consumers' interest but which in reality enhanced the power of utility managers. The changes that happened since questioned the managers' control over the system. Following the technological stasis that occurred in the production of electricity, the oil crisis, and the awakening of the environmental movement, the Government adopted the Public Utility Regulatory Policies Act in 1978, favoring the coming of cogeneration technologies benefiting the small producers. Market economy tended to replace natural monopoly. Deregulation became a valuable option and was stimulated by the 1992 Energy Policy Act. However, the electrical crisis in California and the recent blackout over part of the continent slowed down the pace of the change

Possibilities of optimizing non-nuclear simulation of pressurized water reactor transients

International Nuclear Information System (INIS)

Silva Filho, E.

1985-01-01

The GKSS-Forschungszentrum Geesthacht GmbH has instituted the concept of a scaled test facility (volume scale factor of 1/100) of a typical PWR of the 1 300 MWe class for the purpose of studying small breaks Loss-of-Coolant Accidents (LOCA) and transients. Having in mind the goal of an optimization of this concept has been choosen a station blackout with and without reactor shutdown and a small break LOCA in a primary loop piping to investigate the thermohydraulic behaviour of the test facility in comparison to the reactor plant. The computer code RELAP 5/MOD 1 has been utilized to compare the test facility behaviour with the reactor plant one. Recommendations are given for minimization of distortions between test facility and reactor plant. (orig./HP) [de

What organizations did (and didn't) do: Three factors that shaped conservation responses to California's 2001 'crisis'

Energy Technology Data Exchange (ETDEWEB)

Janda, Kathryn; Payne, Christopher; Kunkle, Rick; Lutzenhiser, Loren

2002-08-18

Beginning in the summer of 2000, California experienced energy supply problems, sharp increases in electricity and natural gas prices, and isolated blackouts. In response, California's state government implemented an unprecedented energy conservation effort to mitigate projected electricity supply shortages during the summer of 2001. Ultimately, significant electricity demand and consumption reductions were achieved. This paper considers the response of commercial and institutional organizations to the California energy situation and offers a description of three factors that shaped these responses: (1) concern about energy problems; (2) operational conditions; and (3) institutional capacity for action. A matrix of possible combinations of concern, conditions, and capacity offers a heuristic for use in exploring how to best tailor and target policy interventions to the circumstances of particular subgroups of organizations.

Screening and analysis of beyond design basis accident of 49-2 SPR

International Nuclear Information System (INIS)

Zhang Yadong; Guo Yue; Wu Yuanyuan; Zou Yao

2015-01-01

The beyond design basis accident was analyzed to ensure safe operation of 49-2 Swimming Pool Reactor (SPR) after design life. Because it's difficult to use PSA method, the unconditional assumed severe accidents were adopted to obtain a conservative result. The main conclusions were obtained by analyzing anticipated transients without scram in station blackout (SBO ATWS), horizontal channel rupture, core uncovering after shutdown and emergency response capacity. The results show that the core is safe in SBO ATWS, and the fuel elements will not melt as long as the core are not exposed in 2.5 h in loss of coolant accident caused by horizontal channel rupture and other factors. The passive siphon breaker function and various ways of emergency core makeup can ensure that the core is not exposed. (authors)

Is energy-rich Alberta about to face an energy crisis?

International Nuclear Information System (INIS)

Horne, D.

2009-01-01

Alberta's growing economy may be hindered by rapidly increasing natural gas and electricity prices. The provincial government has recently removed programs designed to protect consumers from rising prices. The programs consisted of rebates on natural gas as well as a monthly regulated electricity rate. Several companies have recently moved away from the province as a result of higher electricity prices. Currently, the province's electricity market only provides an accurate number for electricity prices for the last hour, and consumers are not aware of the actual prices until after the power has been used. A lack of new transmission may also cause future blackouts to the electric power system. It was concluded that changes to the current billing system are also required in order to protect Alberta's consumers. 1 fig.

Distributed Power System Virtual Inertia Implemented by Grid-Connected Power Converters

DEFF Research Database (Denmark)

Fang, Jingyang; Li, Hongchang; Tang, Yi

2018-01-01

Renewable energy sources (RESs), e.g. wind and solar photovoltaics, have been increasingly used to meet worldwide growing energy demands and reduce greenhouse gas emissions. However, RESs are normally coupled to the power grid through fast-response power converters without any inertia, leading...... to decreased power system inertia. As a result, the grid frequency may easily go beyond the acceptable range under severe frequency events, resulting in undesirable load-shedding, cascading failures, or even large-scale blackouts. To address the ever-decreasing inertia issue, this paper proposes the concept...... of distributed power system virtual inertia, which can be implemented by grid-connected power converters. Without modifications of system hardware, power system inertia can be emulated by the energy stored in the dc-link capacitors of grid-connected power converters. By regulating the dc-link voltages...

Reliability of emergency ac power systems at nuclear power plants

International Nuclear Information System (INIS)

Battle, R.E.; Campbell, D.J.

1983-07-01

Reliability of emergency onsite ac power systems at nuclear power plants has been questioned within the Nuclear Regulatory Commission (NRC) because of the number of diesel generator failures reported by nuclear plant licensees and the reactor core damage that could result from diesel failure during an emergency. This report contains the results of a reliability analysis of the onsite ac power system, and it uses the results of a separate analysis of offsite power systems to calculate the expected frequency of station blackout. Included is a design and operating experience review. Eighteen plants representative of typical onsite ac power systems and ten generic designs were selected to be modeled by fault trees. Operating experience data were collected from the NRC files and from nuclear plant licensee responses to a questionnaire sent out for this project

Insight conference reports : BC power summit

International Nuclear Information System (INIS)

2004-01-01

The papers presented at this conference described recent events and activities in the power industry in British Columbia. Issues concerning distribution, supply and demand were examined as well as the implications of the August blackout to the electric power industry as a whole. Supply initiatives and challenges were examined, including alternative energy initiatives and possibilities for the future. Financing structures and strategies of renewable energy projects were evaluated. The role of regulators was examined as well as details of deregulation in the Pacific North West. Infrastructure development in Alberta was reviewed. Resource planning guidelines were examined. Financing, project financing, demand side management and energy conservation in British Columbia were also discussed. The conference featured 21 presentations, of which 4 have been catalogued separately for inclusion in this database. tabs, figs

MELCOR based severe accident simulation for WWER-440 type nuclear power plants

International Nuclear Information System (INIS)

Vegh, E.; Buerger, L.; Gacs, A.; Gyenes, F.G.; Hozer, Z.; Makovi, P.

1997-01-01

SUBA is a MELCOR based severe accident simulator, installed this summer at the Hungarian Nuclear Safety Directorate. In this simulator the thermohydraulics, chemical reactions and material transport in the primary and secondary systems are calculated by the MELCOR code, but the containment, except the cavity, is modelled by the HERMET code, developed in our Institute. The instrumentation and control, the safety systems and the plant logic, are calculated by our models. This paper describes the main features of the used models and presents three different test transients. The presented transients are as follows: a small break LOCA, a cold leg large break LOCA, and the station blackout, without Diesel generators. In each treated transients the most important parameters are presented as time functions and the most significant events are analysed. (author)

Exodus from nuclear dependent society. The 4th revolution from local initiative

International Nuclear Information System (INIS)

Iida, Tetsunari

2011-01-01

The earthquake and resulting tsunamis occurred in March 11, 2011, caused reactor accidents of the Fukushima Daiichi nuclear power plants (NPPs). Although there appeared a serious gap between power supply and demand due to outages of NPPs and others, appropriate measures taken toward the demand side could save the region from the need for rolling blackouts. In order to realize an exodus from nuclear dependent society, a shift to energy policies for focus on regional distributive renewable energy generation was strongly recommended to revive regional economies devastated by tsunamis and also be a stable energy supply in the long term. A leading player of future electric power might be definitely renewable energy and energy conservation/power saving, that was sometimes called the 'fourth revolution from load initiative'. (T. Tanaka)

SIADH and partial hypopituitarism in a patient with intravascular large B-cell lymphoma: a rare cause of a common presentation

Science.gov (United States)

Akhtar, Simeen; Cheesman, Edmund; Jude, Edward B

2013-01-01

Hyponatraemia is a very common electrolyte abnormality with varied presenting features depending on the underlying cause. The authors report the case of a 75-year-old, previously fit, gentleman who presented with weight loss, lethargy and blackouts. He required four admissions to the hospital over an 8-month period. Investigations revealed persistent hyponatraemia consistent with a diagnosis of syndrome of inappropriate antidiuretic hormone secretion, macrocytic anaemia and partial hypopituitarism. Unfortunately, all other investigations that were performed failed to identify the underlying cause and a diagnosis of intravascular large B-cell lymphoma was only confirmed following postmortem studies. The authors recommend that endocrinologists should be involved at the outset in the management of patients with persistent hyponatraemia and that intravascular large B-cell lymphoma should be considered in the differential diagnosis of hyponatraemia. PMID:23362070

Comparison of various models of emergency power-generator sets; Verschiedene Notstromanlagen im Vergleich. Vor- und Nachteile von redundanten Netzanschluessen, von mobilen und von fest installierten Notstrom-Dieselaggregaten

Energy Technology Data Exchange (ETDEWEB)

Kueng, L. [ewz, Netzdienstleistungen, Zuerich (Switzerland); Felder, R. [Steuerungstechnik, Neudorf (Switzerland)

2006-07-01

This article takes a look at various types of emergency generator sets and reviews their advantages and disadvantages. In the light of various blackout incidents, the call for emergency power supplies has increased as a result of media coverage of such mains disruptions. The article aims to provide aid in asking the right questions and in finding the optimum solution to meet emergency power requirements. Comparisons are limited to solutions involving redundant mains connections and diesel units with power ratings between 250 and 1000 kVA. Mobile and permanently-installed units are looked at. Systems are compared with respect to various criteria, including reaction-time, space-requirements, life expectancy, availability, loading, maintenance, etc. The main advantages and disadvantages are listed. Three examples of real-life solutions are described.

An important year for Swiss Electricity Politics - President's speech at the shareholder's meeting of the Swiss Association of Electricity Enterprises; Strompolitisch relevantes Jahr

Energy Technology Data Exchange (ETDEWEB)

Steiner, R

2004-07-01

This article presents the speech made by Rudolf Steiner, president of the Swiss Association of Electricity Enterprises, in Bad Ragaz in September 2004. Steiner comments on 2004 as being an important year with respect to energy politics in Switzerland. A public vote turned down the idea of opting out of nuclear energy, the Federal Court decided that the Restricted Trade Practices act was also applicable to the Swiss electricity supply industry and the EU parliament passed guidelines on the opening of the European power market. The effects of large-scale blackouts in America and Europe on the public's perception of secure supplies are commented on. The importance of the Association as a provider of services for its members and as a partner for the government is stressed.

Parametric and experimentally informed BWR Severe Accident Analysis Utilizing FeCrAl - M3FT-17OR020205041

Energy Technology Data Exchange (ETDEWEB)

Ott, Larry J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howell, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-08-01

Iron-chromium-aluminum (FeCrAl) alloys are being considered as advanced fuel cladding concepts with enhanced accident tolerance. At high temperatures, FeCrAl alloys have slower oxidation kinetics and higher strength compared with zirconium-based alloys. FeCrAl could be used for fuel cladding and spacer or mixing vane grids in light water reactors and/or as channel box material in boiling water reactors (BWRs). There is a need to assess the potential gains afforded by the FeCrAl accident-tolerant-fuel (ATF) concept over the existing zirconium-based materials employed today. To accurately assess the response of FeCrAl alloys under severe accident conditions, a number of FeCrAl properties and characteristics are required. These include thermophysical properties as well as burst characteristics, oxidation kinetics, possible eutectic interactions, and failure temperatures. These properties can vary among different FeCrAl alloys. Oak Ridge National Laboratory has pursued refined values for the oxidation kinetics of the B136Y FeCrAl alloy (Fe-13Cr-6Al wt %). This investigation included oxidation tests with varying heating rates and end-point temperatures in a steam environment. The rate constant for the low-temperature oxidation kinetics was found to be higher than that for the commercial APMT FeCrAl alloy (Fe-21Cr-5Al-3Mo wt %). Compared with APMT, a 5 times higher rate constant best predicted the entire dataset (root mean square deviation). Based on tests following heating rates comparable with those the cladding would experience during a station blackout, the transition to higher oxidation kinetics occurs at approximately 1,500°C. A parametric study varying the low-temperature FeCrAl oxidation kinetics was conducted for a BWR plant using FeCrAl fuel cladding and channel boxes using the MELCOR code. A range of station blackout severe accident scenarios were simulated for a BWR/4 reactor with Mark I containment. Increasing the FeCrAl low-temperature oxidation rate

Steady state load shedding to mitigate blackout in power systems using an improved harmony search algorithm

Directory of Open Access Journals (Sweden)

R. Mageshvaran

2015-09-01

The proposed algorithm is tested on IEEE 14, 30 and 118 bus test systems. The viability of the proposed method in terms of solution quality and convergence properties is compared with the other conventional methods reported earlier.

Operative and technological management of super-large united power grids: lessons of major world’s blackouts

Directory of Open Access Journals (Sweden)

Brinkis K.

2014-02-01

Full Text Available Neskatoties uz sasniegumiem elektroenerģētikas jomā un energosistēmu nepārtrauktu modernizāciju, pasaulē regulāri notiek sabrukumu avārijas. Rakstā apskatīti lielu un superlielu energosistēmu apvienību savstarpējas sinhronas darbības nodrošinājuma prasības un kritēriji, kas pamatojas uz operatīvās un tehnoloģiskās vadības ciešu koordināciju starp energosistēmām. Savstarpējas sinhronas darbības nodrošinājuma prasībām un kritērijiem ir izšķiroša nozīme, lai panāktu elektroapgādes drošumu un stabilitāti katrā energosistēmā, kas darbojas apvienotas energosistēmas sastāvā. Šo prasību un kritēriju ievērošana sekmē totālo avāriju izcelšanās iespēju samazināšanu un to novēršanu. Indijas 2012.gada totālo avāriju un citu analogo avāriju Eiropā un Amerikā analīze un izvērtējums laika posmā no 2003.gada, deva iespēju apkopot un izstrādāt lielu un superlielu energosistēmu operatīvās un tehnoloģiskās vadības principus un metodoloģiju, lai novērstu vai ierobežotu totālo avāriju izcelsmes iemeslus.

Development of Abnormal Operating Strategies for Station Blackout in Shutdown Operating Mode in Pressurized Water Reactor

Energy Technology Data Exchange (ETDEWEB)

Yoon, Duk-Joo; Lee, Seung-Chan; Sung, Je-Joong; Ha, Sang-Jun [KHNP CRI, Daejeon (Korea, Republic of); Hwang, Su-Hyun [FNC Tech. Co., Yongin (Korea, Republic of)

2016-10-15

Loss of all AC power is classified as one of multiple failure accident by regulatory guide of Korean accident management program. Therefore we need develop strategies for the abnormal operating procedure both of power operating and shutdown mode. This paper developed abnormal operating guideline for loss of all AC power by analysis of accident scenario in pressurized water reactor. This paper analyzed the loss of ultimate heat sink (LOUHS) in shutdown operating mode and developed the operating strategy of the abnormal procedure. Also we performed the analysis of limiting scenarios that operator actions are not taken in shutdown LOUHS. Therefore, we verified the plant behavior and decided operator action to taken in time in order to protect the fuel of core with safety. From the analysis results of LOUHS, the fuel of core maintained without core uncovery for 73 minutes respectively for opened RCS states after the SBO occurred. Therefore, operator action for the emergency are required to take in 73 minutes for opened RCS state. Strategy is to cooldown by using spent fuel pool cooling system. This method required to change the plant design in some plant. In RCS boundary closed state, first abnormal operating strategy in shutdown LOUHS is first abnormal operating strategy in shutdown LOUHS is to remove the residual heat of core by steam dump flow and auxiliary feedwater of SG.

Modeling of a Flooding Induced Station Blackout for a Pressurized Water Reactor Using the RISMC Toolkit

Energy Technology Data Exchange (ETDEWEB)

Mandelli, Diego; Prescott, Steven R; Smith, Curtis L; Alfonsi, Andrea; Rabiti, Cristian; Cogliati, Joshua J; Kinoshita, Robert A

2011-07-01

In the Risk Informed Safety Margin Characterization (RISMC) approach we want to understand not just the frequency of an event like core damage, but how close we are (or are not) to key safety-related events and how might we increase our safety margins. The RISMC Pathway uses the probabilistic margin approach to quantify impacts to reliability and safety by coupling both probabilistic (via stochastic simulation) and mechanistic (via physics models) approaches. This coupling takes place through the interchange of physical parameters and operational or accident scenarios. In this paper we apply the RISMC approach to evaluate the impact of a power uprate on a pressurized water reactor (PWR) for a tsunami-induced flooding test case. This analysis is performed using the RISMC toolkit: RELAP-7 and RAVEN codes. RELAP-7 is the new generation of system analysis codes that is responsible for simulating the thermal-hydraulic dynamics of PWR and boiling water reactor systems. RAVEN has two capabilities: to act as a controller of the RELAP-7 simulation (e.g., system activation) and to perform statistical analyses (e.g., run multiple RELAP-7 simulations where sequencing/timing of events have been changed according to a set of stochastic distributions). By using the RISMC toolkit, we can evaluate how power uprate affects the system recovery measures needed to avoid core damage after the PWR lost all available AC power by a tsunami induced flooding. The simulation of the actual flooding is performed by using a smooth particle hydrodynamics code: NEUTRINO.

Quantifying Improbability: An Analysis of the Lloyd’s of London Business Blackout Cyber Attack Scenario

Science.gov (United States)

Scenarios that describe cyber attacks on the electric grid consistently predict significant disruptions to the economy and citizens quality of life...phenomena that deserve further investigation, such as the importance of some individual power plants in influencing the adversarys probability of

Willingness to pay for public services and quality of supply in the electricity area

International Nuclear Information System (INIS)

Leukert, K.; Telser, H.; Vaterlaus, S.; Mahler, P.

2008-01-01

This report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a study made on the willingness to pay for public services and quality of supply in the electricity area. First, the starting point of the study and definitions of quality of supply and security of supply are noted. The methods used in the study are presented and macro-economic aspects are reviewed. The costs of black-outs are examined and the carrying out of surveys in the electricity market is discussed. The results of surveys made in households and commercial enterprises concerning the willingness to pay for security of supply and the costs incurred when supplies fail are presented and discussed. The report is completed with a comprehensive list of references and an appendix containing the results of the various tests and surveys made.

Application of heat pipes in nuclear reactors for passive heat removal

Energy Technology Data Exchange (ETDEWEB)

Haque, Z.; Yetisir, M., E-mail: haquez@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

2013-07-01

This paper introduces a number of potential heat pipe applications in passive (i.e., not requiring external power) nuclear reactor heat removal. Heat pipes are particularly suitable for small reactors as the demand for heat removal is significantly less than commercial nuclear power plants, and passive and reliable heat removal is required. The use of heat pipes has been proposed in many small reactor designs for passive heat removal from the reactor core. This paper presents the application of heat pipes in AECL's Nuclear Battery design, a small reactor concept developed by AECL. Other potential applications of heat pipes include transferring excess heat from containment to the atmosphere by integrating low-temperature heat pipes into the containment building (to ensure long-term cooling following a station blackout), and passively cooling spent fuel bays. (author)

City of Hoboken Energy Surety Analysis: Preliminary Design Summary

Energy Technology Data Exchange (ETDEWEB)

Stamp, Jason Edwin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Baca, Michael J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Munoz-Ramos, Karina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Schenkman, Benjamin L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Military and Energy Systems Analysis Dept.; Eddy, John P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Systems Readiness and Sustainment Technology Dept.; Smith, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Systems Readiness and Sustainment Technology Dept.; Guttromson, Ross [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electric Power Systems Research Dept.; Henry, Jordan M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Critical Infrastructure Systems Dept.; Jensen, Richard Pearson [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.

2014-09-01

In 2012, Hurricane Sandy devastated much of the U.S. northeast coastal areas. Among those hardest hit was the small community of Hoboken, New Jersey, located on the banks of the Hudson River across from Manhattan. This report describes a city-wide electrical infrastructure design that uses microgrids and other infrastructure to ensure the city retains functionality should such an event occur in the future. The designs ensure that up to 55 critical buildings will retain power during blackout or flooded conditions and include analysis for microgrid architectures, performance parameters, system control, renewable energy integration, and financial opportunities (while grid connected). The results presented here are not binding and are subject to change based on input from the Hoboken stakeholders, the integrator selected to manage and implement the microgrid, or other subject matter experts during the detailed (final) phase of the design effort.

Review of Network Topologies and Protection Principles in Marine and Offshore Applications

DEFF Research Database (Denmark)

Ciontea, Catalin-Iosif; Bak, Claus Leth; Blaabjerg, Frede

2015-01-01

An electric fault that is not cleared is harmful in land applications, but in marine and offshore sector it can have catastrophic consequences. If the protection system fails to operate properly, the following situation may occur: blackouts, fire, loss of propulsion, delays in transportation......, collision with the cliff, reef or other ships and electrical shocks to humans. In order to cope with the unwanted effects of a fault, several protection strategies are applied, but complexity of the marine and offshore applications is continuously increasing, so protection needs to overcome more and more...... challenges. As result, development of new protection techniques that can offer improved functionalities compared to the actual solutions for marine and offshore applications is needed. This paper reviews the network topologies in such applications and presents the requirements of a system able to protect...

European type NPP electric power and vent systems. For safety improvement and proposal of international center

International Nuclear Information System (INIS)

Sugiyama, Kenichiro

2011-01-01

For prevention of reactor accidents of nuclear power plants, multiplicity and redundancy of emergency power would be most important. At station blackout accident, European type manually operated vent operation could minimize release amount of radioactive materials and keep safety of neighboring residents. After Fukushima Daiichi accident, nuclear power plants could not restart operation even after completion of periodical inspection. This article introduced European type emergency power and vent systems in Swiss, Sweden and Germany with state of nuclear power phaseout for reference at considering to upgrade safety and accident mitigation measures for better understanding of the public. In addition, it would be important to recover trust of nuclear technology to continue to disseminate latest information on new knowledge of accident site and decontamination technologies to domestic and overseas people. As its implementation, establishment of Fukushima international center was proposed. (T. Tanaka)

The particular use of PIV methods for the modelling of heat and hydrophysical processes in the nuclear power plants

Science.gov (United States)

Sergeev, D. A.; Kandaurov, A. A.; Troitskaya, Yu I.

2017-11-01

In this paper we describe PIV-system specially designed for the study of the hydrophysical processes in large-scale benchmark setup of promising fast reactor. The system allows the PIV-measurements for the conditions of complicated configuration of the reactor benchmark, reflections and distortions section of the laser sheet, blackout, in the closed volume. The use of filtering techniques and method of masks images enabled us to reduce the number of incorrect measurement of flow velocity vectors by an order. The method of conversion of image coordinates and velocity field in the reference model of the reactor using a virtual 3D simulation targets, without loss of accuracy in comparison with a method of using physical objects in filming area was released. The results of measurements of velocity fields in various modes, both stationary (workers), as well as in non-stationary (emergency).

Safety features of a power unit with the BREST-OD-300 reactor

International Nuclear Information System (INIS)

Smirnov, V.S.

2013-01-01

• Two classes of the most severe accidents have been considered: with positive reactivity introduction and with loss of forced heat removal from the core. • It has been demonstrated that no full reactivity margin introduction during reactor power operations leads to the temperature limits of the fuel element safe operation being exceeded when the EP system or only the Passive EP-T system operates. • It has been shown that no loss of forced heat removal during blackout results in the temperature limits of safe operation being exceeded when at least only passive protections (Passive EP-T and PFBS) operate. • It has been shown that no even most severe accidents involving full reactivity margin introduction (UTOP) and full loss of power for all reactor facility systems (ULOF) lead to fuel melting and coolant boiling

An application of the fault tree analysis for the power system reliability estimation

International Nuclear Information System (INIS)

Volkanovski, A.; Cepin, M.; Mavko, B.

2007-01-01

The power system is a complex system with its main function to produce, transfer and provide consumers with electrical energy. Combinations of failures of components in the system can result in a failure of power delivery to certain load points and in some cases in a full blackout of power system. The power system reliability directly affects safe and reliable operation of nuclear power plants because the loss of offsite power is a significant contributor to the core damage frequency in probabilistic safety assessments of nuclear power plants. The method, which is based on the integration of the fault tree analysis with the analysis of the power flows in the power system, was developed and implemented for power system reliability assessment. The main contributors to the power system reliability are identified, both quantitatively and qualitatively. (author)

Comparison of a Traditional Probabilistic Risk Assessment Approach with Advanced Safety Analysis

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis L; Mandelli, Diego; Zhegang Ma

2014-11-01

As part of the Light Water Sustainability Program (LWRS) [1], the purpose of the Risk Informed Safety Margin Characterization (RISMC) [2] Pathway research and development (R&D) is to support plant decisions for risk-informed margin management with the aim to improve economics, reliability, and sustain safety of current NPPs. In this paper, we describe the RISMC analysis process illustrating how mechanistic and probabilistic approaches are combined in order to estimate a safety margin. We use the scenario of a “station blackout” (SBO) wherein offsite power and onsite power is lost, thereby causing a challenge to plant safety systems. We describe the RISMC approach, illustrate the station blackout modeling, and contrast this with traditional risk analysis modeling for this type of accident scenario. We also describe our approach we are using to represent advanced flooding analysis.

Willingness to pay for public services and quality of supply in the electricity area; Zahlungsbereitschaft fuer Service public und Versorgungsqualitaet im Strombereich

Energy Technology Data Exchange (ETDEWEB)

Leukert, K.; Telser, H.; Vaterlaus, S.; Mahler, P.

2008-07-01

This report for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a study made on the willingness to pay for public services and quality of supply in the electricity area. First, the starting point of the study and definitions of quality of supply and security of supply are noted. The methods used in the study are presented and macro-economic aspects are reviewed. The costs of black-outs are examined and the carrying out of surveys in the electricity market is discussed. The results of surveys made in households and commercial enterprises concerning the willingness to pay for security of supply and the costs incurred when supplies fail are presented and discussed. The report is completed with a comprehensive list of references and an appendix containing the results of the various tests and surveys made.

A review of postural orthostatic tachycardia syndrome.

LENUS (Irish Health Repository)

Carew, Sheila

2012-01-31

A 21-year-old female reports an 18-month history of light-headedness on standing. This is often associated with palpitations and a feeling of intense anxiety. She has had two black-outs in the past 12 months. She is not taking any regular medications. Her supine blood pressure was 126\\/84 mmHg with a heart rate of 76 bpm, and her upright blood pressure was 122\\/80 mmHg with a heart rate of 114 bpm. A full system examination was otherwise normal. She had a 12-lead electrocardiogram performed which was unremarkable. She was referred for head-up tilt testing. She was symptomatic during the test and lost consciousness at 16 min. Figure 1 summarizes her blood pressure and heart rate response to tilting. A diagnosis of postural orthostatic tachycardia syndrome with overlapping vasovagal syncope was made.

Recent SCDAP/RELAP5 improvements for BWR severe accident simulations

International Nuclear Information System (INIS)

Griffin, F.P.

1995-01-01

A new model for the SCDAP/RELAP5 severe accident analysis code that represents the control blade and channel box structures in a boiling water reactor (BWR) has been under development since 1991. This model accounts for oxidation, melting, and relocation of these structures, including the effects of material interactions between B 4 C, stainless steel, and Zircaloy. This paper describes improvements that have been made to the BWR control blade/channel box model during 1994 and 1995. These improvements include new capabilities that represent the relocation of molten material in a more realistic manner and modifications that improve the usability of the code by reducing the frequency of code failures. This paper also describes a SCDAP/RELAP5 assessment calculation for the Browns Ferry Nuclear Plant design based upon a short-term station blackout accident sequence

Analysis of core damage frequency from internal events: Surry, Unit 1

International Nuclear Information System (INIS)

Harper, F.T.

1986-11-01

This document contains the accident sequence analyses for Surry, Unit 1; one of the reference plants being examined as part of the NUREG-1150 effort by the Nuclear Regulatory Commission (NRC). NUREG-1150 will document the risk of a selected group of nuclear power plants. As part of that work, this report contains the overall core damage frequency estimate for Surry, Unit 1, and the accompanying plant damage state frequencies. Sensitivity and uncertainty analyses provide additional insights regarding the dominant contributors to the Surry core damage frequency estimate. The numerical results are driven to some degree by modeling assumptions and data selection for issues such as reactor coolant pump seal LOCAs, common cause failure probabilities, and plant response to station blackout and loss of electrical bust initiators. The sensitivity studies explore the impact of alternate theories and data on these issues

Conjugate heat transfer analysis of multiple enclosures in prototype fast breeder reactor

Energy Technology Data Exchange (ETDEWEB)

Velusamy, K.; Balaubramanian, V.; Vaidyanathan, G.; Chetal, S.C. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

1995-09-01

Prototype Fast Breeder Reactor (PFBR) is a 500 MWe sodium cooled reactor under design. The main vessel of the reactor serves as the primary boundary. It is surrounded by a safety vessel which in turn is surrounded by biological shield. The gaps between them are filled with nitrogen. Knowledge of temperature distribution prevailing under various operating conditions is essential for the assessment of structural integrity. Due to the presence of cover gas over sodium free level within the main vessel, there are sharp gradients in temperatures. Also cover gas height reduces during station blackout conditions due to sodium level rise in main vessel caused by temperature rise. This paper describes the model used to analyse the natural convection in nitrogen, conduction in structures and radiation interaction among them. Results obtained from parametric studies for PFBR are also presented.

Security assessment for intentional island operation in modern power system

DEFF Research Database (Denmark)

Chen, Yu; Xu, Zhao; Østergaard, Jacob

2011-01-01

be increased. However, when to island or how to ensure the islanded systems can survive the islanding transition is uncertain. This article proposes an Islanding Security Region (ISR) concept to provide security assessment of island operation. By comparing the system operating state with the ISR, the system......There has been a high penetration level of Distributed Generations (DGs) in distribution systems in Denmark. Even more DGs are expected to be installed in the coming years. With that, to utilize them in maintaining the security of power supply is of great concern for Danish utilities. During...... the emergency in the power system, some distribution networks may be intentionally separated from the main grid to avoid complete system collapse. If DGs in those networks could continuously run instead of immediately being shut down, the blackout could be avoided and the reliability of supply could...

Visceral predictors of cardiovascular deconditioning in late middle-aged men

Science.gov (United States)

Goldwater, D. J.; De Roshia, C.; Natelson, B. H.; Levin, B. E.

1985-01-01

A number of visceral and behavioral factors connected with cardiovascular deconditioning were investigated, in order to identify a method for predicting the degree of orthostatic intolerance to spaceflight in several late-middle-aged men (55-65 years). Preliminary measurements were made of: mean arterial blood pressure plasma cortisol levels; and norepinephrine levels. Measurements of core temperature; plasma epinephrine level and subjective arousal from sleep were also obtained. Pairwise correlations were found for each of the variables and the time-to-blackout due centrifugal acceleration of up to +3 Gz. It is shown that the men with relatively low resting blood pressure were at greater risk of developing the clinical signs of cardiovascular deconditioning than were the men with higher basal blood pressure. Some applications of the experimental results to the development of selection criteria for Shuttle crews are discussed.

Comparison of the course of events at the nuclear power plants on grid disturbance 1983-12-27

International Nuclear Information System (INIS)

1984-01-01

At the time of the disturbance which caused the 1983-12-27 blackout in southern Sweden, the area was a net importer of electricity. A fault cut out 2 out of 6 lines feeding the area, and most of the grid tripped. At the time 8 nuclear power units were producing into the grid which tripped. 7 of the 8 units scrammed. One unit could keep a 45% level of production, and restore full power within one hour. The other 7 units were back in production only after 12 hours ore more. The report gives case histories for all units, and goes on to discuss construction parameters relevant to the faults. The capacity for steam dumping when a power grid is tripped is discussed. The dumping capacities and experiences for the utilities of other countries are related. (Aa)

Design and development of self-powered sensors on wireless sensor network for standalone plant critical data management during SBO and beyond design basis events

International Nuclear Information System (INIS)

Aparna, J.; Dulera, I.V.; Rama Rao, A.; Vijayan, P.K.

2015-01-01

Advanced reactors are designed with an aim of maximum safety, optimized fuel utilization and effective system design. Safety aspects in reactor designs are being viewed for all possible vulnerabilities, and as a result, robust self-regulating passive safety features have been favored in Gen IV and advanced reactor designs. In addition to passive systems, the accidents scenarios at Fukushima indicate the dire need of reliable and stand-alone self-powered sensors, for monitoring plant critical parameters for effective damage control actions. There is a strong need for plant critical data management and situation awareness during the unavailability of all conventional power sources in a nuclear power plant, during extended station blackout (SBO) conditions. These self-powered sensors would assist the operators in managing events like SBO and help in containing any Beyond Design Basis Events (BDBE) conditions, well away from the public domain

Scheduling home appliances for energy efficient buildings

DEFF Research Database (Denmark)

Rossello Busquet, Ana; Kardaras, Georgios; Iversen, Villy Bæk

2010-01-01

The number of appliances found in users’ homes is increasing together with electricity consumption of users’ residences. In addition, there is a tendency to consume during the same period leading to demand peaks. During these periods, electricity providers are forced to develop costly methods...... to generate enough power to meet consumers’ requirements. In addition, high demand peaks can lead to electricity shortages or even blackouts in certain areas. In order to avoid demand peaks, users’ appliances should consume electricity in a more distributed way. A new methodology to schedule the usage of home...... appliances is proposed and analyzed. The main concept behind this approach is the aggregation of home appliances into priority classes and the definition of a maximum power consumption threshold, which is not allowed to be exceeded during peak hours. The scenario simulated describes a modern household, where...

A Comparison of the Alcohol Use Disorder Identification Test (AUDIT) in General Population Surveys in nine European Countries

DEFF Research Database (Denmark)

Bloomfield, Kim; Knibbe, Ronald; Derickx, Mieke

2006-01-01

Aims: This study explored the suitability of the Alcohol Use Disorder Identification Test (AUDIT) for cross-national comparable estimates of problem drinking in general populations. On the item level the focus is on responsiveness to cross-national and gender differences. For the set of items...... the focus is on intercorrelations between items, indicating to what extent the AUDIT constitutes a scale. Methods: General population surveys from nine European countries were included. Cross-tabulations were used to analyse cross-national and gender differences in scores on the items. Reliability analysis...... was used to analyse intercorrelations between the items. Results: The items ‘blackouts' (men and women) and ‘guilt and remorse' (women) are the most frequently reported consequences. Gender differences tended to be smaller for ‘guilt and remorse' and ‘concern of others', and largest for ‘morning drinking...

Intelligent Techniques for Power Systems Vulnerability Assessment

Directory of Open Access Journals (Sweden)

Mohamed A. El-Sharkawi

2002-06-01

Full Text Available With power grids considered national security matters, the reliable operation of the system is of top priority to utilities.  This concern is amplified by the utility’s deregulation, which increases the system’s openness while simultaneously decreasing the applied degree of control.  Vulnerability Assessment (VA deals with the power system’s ability to continue to provide service in case of an unforeseen catastrophic contingency.  Such contingencies may include unauthorized tripping, breaks in communication links, sabotage or intrusion by external agents, human errors, natural calamities and faults.  These contingencies could lead to a disruption of service to part or all of the system.  The service disruption is known as outage or blackout.  The paper outlines an approach by which feature extraction and boundary tracking can be implemented to achieve on line vulnerability assessment.

Basic Research Needs for Superconductivity. Report of the Basic Energy Sciences Workshop on Superconductivity, May 8-11, 2006

Energy Technology Data Exchange (ETDEWEB)

Sarrao, J.; Kwok, W-K; Bozovic, I.; Mazin, I.; Seamus, J. C.; Civale, L.; Christen, D.; Horwitz, J.; Kellogg, G.; Finnemore, D.; Crabtree, G.; Welp, U.; Ashton, C.; Herndon, B.; Shapard, L.; Nault, R. M.

2006-05-11

As an energy carrier, electricity has no rival with regard to its environmental cleanliness, flexibility in interfacing with multiple production sources and end uses, and efficiency of delivery. In fact, the electric power grid was named ?the greatest engineering achievement of the 20th century? by the National Academy of Engineering. This grid, a technological marvel ingeniously knitted together from local networks growing out from cities and rural centers, may be the biggest and most complex artificial system ever built. However, the growing demand for electricity will soon challenge the grid beyond its capability, compromising its reliability through voltage fluctuations that crash digital electronics, brownouts that disable industrial processes and harm electrical equipment, and power failures like the North American blackout in 2003 and subsequent blackouts in London, Scandinavia, and Italy in the same year. The North American blackout affected 50 million people and caused approximately $6 billion in economic damage over the four days of its duration. Superconductivity offers powerful new opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency. Superconductors are capable of carrying current without loss, making the parts of the grid they replace dramatically more efficient. Superconducting wires carry up to five times the current carried by copper wires that have the same cross section, thereby providing ample capacity for future expansion while requiring no increase in the number of overhead access lines or underground conduits. Their use is especially attractive in urban areas, where replacing copper with superconductors in power-saturated underground conduits avoids expensive new underground construction. Superconducting transformers cut the volume, weight, and losses of conventional transformers by a factor of two and do not require the contaminating and flammable transformer oils that violate urban safety

Human Factors for Situation Assessment in Grid Operations

Energy Technology Data Exchange (ETDEWEB)

Guttromson, Ross T.; Schur, Anne; Greitzer, Frank L.; Paget, Mia L.

2007-08-08

Executive Summary Despite advances in technology, power system operators must assimilate overwhelming amounts of data to keep the grid operating. Analyses of recent blackouts have clearly demonstrated the need to enhance the operator’s situation awareness (SA). The long-term objective of this research is to integrate valuable technologies into the grid operator environment that support decision making under normal and abnormal operating conditions and remove non-technical barriers to enable the optimum use of these technologies by individuals working alone and as a team. More specifically, the research aims to identify methods and principles to increase SA of grid operators in the context of system conditions that are representative or common across many operating entities and develop operationally relevant experimental methods for studying technologies and operational practices which contribute to SA. With increasing complexity and interconnectivity of the grid, the scope and complexity of situation awareness have grown. New paradigms are needed to guide research and tool development aimed to enhance and improve operations. In reviewing related research, operating practices, systems, and tools, the present study established a taxonomy that provides a perspective on research and development surrounding power grid situation awareness and clarifies the field of human factors/SA for grid operations. Information sources that we used to identify critical factors underlying SA included interviews with experienced operational personnel, available historical summaries and transcripts of abnormal conditions and outages (e.g., the August 14, 2003 blackout), scientific literature, and operational policies/procedures and other documentation. Our analysis of August 2003 blackout transcripts and interviews adopted a different perspective than previous analyses of this material, and we complemented this analysis with additional interviews. Based on our analysis and a broad

Basic Research Needs for Superconductivity. Report of the Basic Energy Sciences Workshop on Superconductivity, May 8-11, 2006

International Nuclear Information System (INIS)

Sarrao, J.; Kwok, W-K; Bozovic, I.; Mazin, I.; Seamus, J. C.; Civale, L.; Christen, D.; Horwitz, J.; Kellogg, G.; Finnemore, D.; Crabtree, G.; Welp, U.; Ashton, C.; Herndon, B.; Shapard, L.; Nault, R. M.

2006-01-01

As an energy carrier, electricity has no rival with regard to its environmental cleanliness, flexibility in interfacing with multiple production sources and end uses, and efficiency of delivery. In fact, the electric power grid was named ?the greatest engineering achievement of the 20th century? by the National Academy of Engineering. This grid, a technological marvel ingeniously knitted together from local networks growing out from cities and rural centers, may be the biggest and most complex artificial system ever built. However, the growing demand for electricity will soon challenge the grid beyond its capability, compromising its reliability through voltage fluctuations that crash digital electronics, brownouts that disable industrial processes and harm electrical equipment, and power failures like the North American blackout in 2003 and subsequent blackouts in London, Scandinavia, and Italy in the same year. The North American blackout affected 50 million people and caused approximately $6 billion in economic damage over the four days of its duration. Superconductivity offers powerful new opportunities for restoring the reliability of the power grid and increasing its capacity and efficiency. Superconductors are capable of carrying current without loss, making the parts of the grid they replace dramatically more efficient. Superconducting wires carry up to five times the current carried by copper wires that have the same cross section, thereby providing ample capacity for future expansion while requiring no increase in the number of overhead access lines or underground conduits. Their use is especially attractive in urban areas, where replacing copper with superconductors in power-saturated underground conduits avoids expensive new underground construction. Superconducting transformers cut the volume, weight, and losses of conventional transformers by a factor of two and do not require the contaminating and flammable transformer oils that violate urban safety

Foul WX Underground: The Dynamics of Resistance and the Analog Logic of Communication during a Digital Blackout

Science.gov (United States)

2009-05-21

based interrogations, often using a distributed network of machines to reduce the sequential nature of finite but still time- consuming actions, the...competition‘s players are yelling commands that are indistinguishable from their own teammates‘ commands. Resonance Commercial advertising jingles ...tactic.‖ in Attitudes, behaviour and social context: the role of norms and group membership, ed. D. J. Terry and M. A. Hagg (Mahwah, NJ: Lawrence

Calculations of a station blackout transient in a RBMK type nuclear power plant with the CATHARE code

International Nuclear Information System (INIS)

Niklaus, F.; Korteniemi, V.

1996-01-01

At the Department of Energy Technology at Lappeenranta University of Technology a CATHARE model of one unit of the St. Petersburg (RBMK) nuclear power plant has been generated. The investigations have been done in order to understand better the thermal-hydraulic behaviour of RBMK type reactors and in order to see how far the French thermal-hydraulic safety code CATHARE can predict the physical phenomena during various RBMK transients. (12 refs.)

Sudden f/sub min/ enhancements and sudden cosmic noise absorptions associated with solar X-ray flares

Energy Technology Data Exchange (ETDEWEB)

Sato, T [Hyogo Coll. of Medicine, Hyogo (Japan). Dept. of Physics

1975-01-01

Sudden fsub(min) enhancements (SFsub(m)E's) and sudden cosmic noise absorptions (SCNA's) associated with increments of X-ray fluxes during solar flares are studied on the basis of X-ray flux data measured by SOLRAD 9 and 10 satellites. Some statistical analyses on SFsub(m)E's observed at five observatories in Japan, corresponding to increased X-ray fluxes in the 1-8 A band are made for 50 solar flare events during the period January 1972 to December 1973, and value of fsub(min) is expressed as functions of cos x(x; solar zenith angle) and 1-8 A band X-ray flux. Similar study is also made for SCNA's observed by 30 MHz riometer at Hiraiso for 15 great solar flare events during the same period, together with 27.6 MHz riometer data reported by Schwentek (1973) and 18 MHz data published by Deshpande and Mitra (1972b). It is found that fsub(min) value (MHz) and SCNA value (L, dB) of a radio wave with frequency f(MHz) are related to X-ray flux (F/sub 0/, erg cm/sup -2/ sec/sup -1/) in the 1-8 A band and to cos x, by following approximate expressions, fsub(min)(MHz)=10F/sub 0/sup(1/4) cossup(1/2) x, and L(dB)=4.37x10/sup 3/f/sup -2/F/sub 0/sup(1/2) cos x, respectively. Blackout seems to occur for F/sub 0/ values causing fsub(min)'s greater than about 5 MHz. It is shown that these expressions can be derived from a brief theoretical calculation of radio wave absorption in the lower ionosphere. Also it is suggested that threshold X-ray fluxes in the 1-8 A band which may produce a minimum SFsub(m)E (2 MHz), blackout and minimum SCNA (0.27-0.36 dB for 30 MHz noise) are 1.6x10/sup -3/, 6.2x10/sup -2/ and (3-8) x 10/sup -3/ erg cm/sup -2/ sec/sup -1/, respectively, for cos x=1.

Four Essays on Applied Energy Economics and Policy

Science.gov (United States)

Buenestado, Raul Bajo

This thesis is divided in two parts. The first part (chapters 1 and 2) studies capacity payments in the electricity sector. The second part (chapter 3 and 4) is on gasoline retail markets. The first chapter explores welfare implications of capacity markets in the electricity sector. We propose a theoretical model with cost heterogeneous firms, for which price and quantity equilibria are obtained both with and without a capacity market. The consequences for consumers are assessed using three different measures: consumer surplus, probability of blackout and price volatility. We conclude that a capacity market is able to reduce extreme events. Under some circumstances, we show that a capacity market is also efficiency enhancing. In the second chapter, we use data from the Texas ERCOT to study the impact of capacity payments in a stylized wholesale electricity market. We find that the introduction of capacity payments has two countervailing effects. On the one hand, it increases consumers' bills. On the other hand, it reduces price volatility and blackout probability. We find that the net impact on consumer surplus is negative both in a perfectly competitive market and in the presence of market power. In the third chapter, we use monthly data from the Spanish gasoline retail market to explore asymmetries in consumers' responses to changes in gasoline prices and taxes. We investigate whether an increase in taxes has a more negative impact on the demand than an increase in the "pre-tax" price of gasoline. We estimate consumers' behavioral responses using a rich set of robust models. We find evidence of asymmetric responses for the demand of unleaded fuels and agricultural diesel fuel. In the final chapter we study a game of spatial competition in prices. We focus on the linear city duopoly model to see what we can learn about the distribution of consumers, which is approximated using variation in equilibrium prices and costs. We apply our methodology to a dataset on

CRISP. Dependable ICT Support of Power Grid Operations

Energy Technology Data Exchange (ETDEWEB)

Gustavsson, R.; Mellstrand, P.; Tornqvist, B. [Blekinge Institute of Technology BTH, Karlskrona (Sweden); Akkermans, H. [EnerSearch, Malmoe (Sweden)

2005-03-15

This deliverable D2.4 Dependable ICT support 0f Power Grid Operations is a link between deliverable D1.6 Information security models and their economics and planned activities in WP III, that is, Implementation, Experiments and Tests. Background CRISP material includes deliverables of D2.2 Design document and multi-agent simulation tool for distributed demand-supply matching and D2.3 Design document and simulation tool for diagnostics of high-DG power networks. Furthermore there are links between this document and the deliverable D1.7 Report on distributed network architectures and D1.8 Reports on case study simulations and results. In short, this document specifies and extends the general background on security models and dependability models of deliverable D1.6 with CRISP specific material of D2.2 and D2.4 towards the experiments and tests of WP III. The focus of this deliverable is on dependable ICT support of power grid operation. By recasting the three CRISP experiments into three Scenarios in Chapter 2 we claim that we have a good description of benefits and challenges related to future virtual utilities. Among the challenges are securing trustworthy operation from a technical operation side (avoid disturbances such as blackouts) as wee as from a user-centric business point of view (value added power related services). Our investigation on proper means to safeguard operations of future virtual utilities begins with an assessment of lessons learned from recent (2003) big blackouts worldwide in Chapter 3. We propose an accident diagnosis and repair model (STAMP in Section 3.2) suitable for the complex socio-technical system we envisage for future cell-based virtual utilities. From this analysis and the background material from deliverable D1.6 Information security models and their economics, we then reassess the dependability concerns related to the CRISP related scenarios of Chapter 2. The deliverable provides some novel ideas and models that we claim are

CRISP. Dependable ICT Support of Power Grid Operations

International Nuclear Information System (INIS)

Gustavsson, R.; Mellstrand, P.; Tornqvist, B.; Akkermans, H.

2005-03-01

This deliverable D2.4 Dependable ICT support 0f Power Grid Operations is a link between deliverable D1.6 Information security models and their economics and planned activities in WP III, that is, Implementation, Experiments and Tests. Background CRISP material includes deliverables of D2.2 Design document and multi-agent simulation tool for distributed demand-supply matching and D2.3 Design document and simulation tool for diagnostics of high-DG power networks. Furthermore there are links between this document and the deliverable D1.7 Report on distributed network architectures and D1.8 Reports on case study simulations and results. In short, this document specifies and extends the general background on security models and dependability models of deliverable D1.6 with CRISP specific material of D2.2 and D2.4 towards the experiments and tests of WP III. The focus of this deliverable is on dependable ICT support of power grid operation. By recasting the three CRISP experiments into three Scenarios in Chapter 2 we claim that we have a good description of benefits and challenges related to future virtual utilities. Among the challenges are securing trustworthy operation from a technical operation side (avoid disturbances such as blackouts) as wee as from a user-centric business point of view (value added power related services). Our investigation on proper means to safeguard operations of future virtual utilities begins with an assessment of lessons learned from recent (2003) big blackouts worldwide in Chapter 3. We propose an accident diagnosis and repair model (STAMP in Section 3.2) suitable for the complex socio-technical system we envisage for future cell-based virtual utilities. From this analysis and the background material from deliverable D1.6 Information security models and their economics, we then reassess the dependability concerns related to the CRISP related scenarios of Chapter 2. The deliverable provides some novel ideas and models that we claim are

Demonstration of a Novel Synchrophasor-based Situational Awareness System: Wide Area Power System Visualization, On-line Event Replay and Early Warning of Grid Problems

Energy Technology Data Exchange (ETDEWEB)

Rosso, A.

2012-12-31

Since the large North Eastern power system blackout on August 14, 2003, U.S. electric utilities have spent lot of effort on preventing power system cascading outages. Two of the main causes of the August 14, 2003 blackout were inadequate situational awareness and inadequate operator training In addition to the enhancements of the infrastructure of the interconnected power systems, more research and development of advanced power system applications are required for improving the wide-area security monitoring, operation and planning in order to prevent large- scale cascading outages of interconnected power systems. It is critically important for improving the wide-area situation awareness of the operators or operational engineers and regional reliability coordinators of large interconnected systems. With the installation of large number of phasor measurement units (PMU) and the related communication infrastructure, it will be possible to improve the operators’ situation awareness and to quickly identify the sequence of events during a large system disturbance for the post-event analysis using the real-time or historical synchrophasor data. The purpose of this project was to develop and demonstrate a novel synchrophasor-based comprehensive situational awareness system for control centers of power transmission systems. The developed system named WASA (Wide Area Situation Awareness) is intended to improve situational awareness at control centers of the power system operators and regional reliability coordinators. It consists of following main software modules: • Wide-area visualizations of real-time frequency, voltage, and phase angle measurements and their contour displays for security monitoring. • Online detection and location of a major event (location, time, size, and type, such as generator or line outage). • Near-real-time event replay (in seconds) after a major event occurs. • Early warning of potential wide-area stability problems. The system has been

Understanding the response of commercial and institutional organizations to the California energy crisis. A report to the California Energy Commission - Sylvia Bender, Project Manager

Energy Technology Data Exchange (ETDEWEB)

Lutzenhiser, Loren; Janda, Kathryn; Kunkle, Rick; Payne, Christopher

2002-07-24

Beginning in the summer of 2000, California experienced serious energy supply problems, sharp increases in wholesale (and retail) electricity and natural gas prices, and isolated blackouts. In response to the rapidly worsening electricity situation in California in late 2000, the state set, as an initial goal, the reduction of the state's peak demand for the summer of 2001 by 5,000 megawatts. To meet this goal, the governor and legislature took a variety of steps to enhance supply, encourage rapid voluntary reductions in demand, and provide incentives for actions that would result in load reductions. Three bills-Assembly Bill 970, Senate Bill X1 5 and Assembly Bill X1 29-allocated roughly $950 million for consumption and demand reduction programs. The governor also enacted a variety of additional measures, including the ''Flex Your Power'' (media awareness and direct business involvement) campaign, requirements for retail sector outdoor lighting reductions, and toughening of energy efficiency building codes. There were, in fact, significant reductions in electricity demand in California during the summer of 2001 and the large number of expected supply disruptions was avoided. To understand the nature of these demand reductions and the motivations for consumer response, Washington State University (WSU) undertook a study for the California Energy Commission (CEC) focusing on conservation behavior in the residential, commercial, and agricultural sectors. The research presented in this report represents an exploration of the response of commercial and institutional organizations to the California energy situation and the unique set of influences that existed during this time. These influences included informational messages and media attention, program interventions, price changes, and external triggering events (e.g., blackouts). To better understand the effects of these influences on organizational response to the energy situation, we

Astronomy Week in Madeira, Portugal

Science.gov (United States)

Augusto, P.; Sobrinho, J. L.

2012-05-01

The outreach programme Semanas da Astronomia (Astronomy Weeks) is held in late spring or summer on the island of Madeira, Portugal. This programme has been attracting enough interest to be mentioned in the regional press/TV/radio every year and is now, without doubt, the astronomical highlight of the year on Madeira. We believe that this programme is a good case study for showing how to attract the general public to astronomy in a small (population 250 000, area 900 km2) and fairly isolated place such as Madeira. Our Astronomy Weeks have been different each year and have so far included exhibitions, courses, talks, a forum, documentaries, observing sessions (some with blackouts), music and an astro party. These efforts may contribute towards putting Madeira on the map with respect to observational astronomy, and have also contributed to the planned installation of two observatories in the island.

Containment response and radiological release for a TMLB' accident sequence in a large dry containment

International Nuclear Information System (INIS)

Gasser, R.D.; Bieniarz, P.P.; Tills, J.L.

1987-01-01

An analysis has been performed for the Bellefonte Pressurized Water Reactor (PWR) Unit 1 to determine the containment loading and the radiological releases into the environment from a station blackout accident. A number of issues have been addressed in this analysis, which include the effects of direct heating on containment loading and the effects of fission product heating and natural convection on releases from the primary system. The results indicate that direct heating, which involves more than about 50% of the core, may fail the Bellefonte containment, but natural convection in the Reactor Coolant System (RCS) may lead to overheating and failure of the primary system piping before core slump, thus, eliminating or mitigating direct heating. Releases from the primary system are significantly increased before vessel breach, due to natural circulation, and after vessel breach, due to reevolution of retained fission products by fission product heating of RCS structures. (orig.)

Profound hypoglycemia-ınduced by vaccinium corymbosum juice and laurocerasus fruit.

Science.gov (United States)

Aktan, Ahmet Hamdi; Ozcelik, Abdullah; Cure, Erkan; Cure, Medine Cumhur; Yuce, Suleyman

2014-01-01

An emergency intervention was performed in a 75-year-old male patient with hypoglycemic attack and blackout. Although he was diagnosed with prediabetes before 2 years, he did not take any anti-diabetic drug or follow dietary advice. He drank Vaccinium corymbosum L (VC) juice daily with a belief that it increases sexual potency. Before the development of hypoglycemia, the patient had consumed about 500 ml VC juice in addition to eating 200-300 gram of Laurocerasus officinalis (LO) fruit. The measured plasma glucose (PG) level during loss of consciousness was 30 mg/dl. The profound hypoglycemia may be an unexpected side effect of an interaction between the chemical compositions of the two plants, occurred as a result of LO fruit intake that may have a strong PG-lowering effect or related to excessive intake of VC juice. Both plants may be considered in the alternative treatment of diabetes.

Insights from the interim reliability evaluation program pertinent to reactor safety issues

International Nuclear Information System (INIS)

Carlson, D.D.

1983-01-01

The Interim Reliability Evaluation Program (IREP) consisted of concurrent probabilistic analyses of four operating nuclear power plants. This paper presents and integrated view of the results of the analyses drawing insights pertinent to reactor safety. The importance to risk of accident sequences initiated by transients and small loss-of-coolant accidents was confirmed. Support systems were found to contribute significantly to the sets of dominant accident sequences, either due to single failures which could disable one or more mitigating systems or due to their initiating plant transients. Human errors in response to accidents also were important risk contributors. Consideration of operator recovery actions influences accident sequence frequency estimates, the list of accident sequences dominating core melt, and the set of dominant risk contributors. Accidents involving station blackout, reactor coolant pump seal leaks and ruptures, and loss-of-coolant accidents requiring manual initiation of coolant injection were found to be risk significant

Present status of research reactor and future prospects

International Nuclear Information System (INIS)

Nakajima, Ken

2013-01-01

Research reactors have been playing an important role in the research and development of the various fields, such as physics, chemistry, biology, engineering, agriculture, medicine, etc. as well as human resource development. However, the most of them are older than 40 years, and the ageing management is an important issue. In Japan, only two research reactors are operational after the Great East Japan Earthquake in 2011. JAEA's reactors suffered from the quake and they are under inspections. Kyoto University Research Reactor, one of the operational reactors, has been widely used for research and human resource development, and the additional safety measures against the station blackout were installed. Besides the affect of the quake, the disposal or treatment of spent fuel becomes an inevitable problem for research reactors. The way of spent fuel disposal or treatment should be determined with the nation-wide and/or international coalition. (author)

France liberalizes its power supply market

International Nuclear Information System (INIS)

Anon.

2004-01-01

The French market of power supply to companies is now free. This means that Electricite de France (EdF), the first world electric utility now has competitors in its domestic market. This is an important challenge for EdF because 3 millions of clients (70% of the French power consumption) are now concerned by the opening of the power market. According to A. Merlin, head of the energy transportation network (RTE), the opening of the market does not increase the risk of black-out, it just makes the operation of power networks more complex. The implementation of a single power transportation company (RTE) simplifies the mastery of networks safety but the development of investments is necessary to ensure the maintenance of 400 kV power lines. A comparison of the situation of power market liberalization is made for 6 countries (Germany, UK, Spain, US, Netherlands and Italy). Short paper. (J.S.)

Detailed evaluation of RCS boundary rupture during high-pressure severe accident sequences

International Nuclear Information System (INIS)

Park, Rae-Joon; Hong, Seong-Wan

2011-01-01

A depressurization possibility of the reactor coolant system (RCS) before a reactor vessel rupture during a high-pressure severe accident sequence has been evaluated for the consideration of direct containment heating (DCH) and containment bypass. A total loss of feed water (TLOFW) and a station blackout (SBO) of the advanced power reactor 1400 (APR 1400) has been evaluated from an initiating event to a creep rupture of the RCS boundary by using the SCDAP/RELAP5 computer code. In addition, intentional depressurization of the RCS using power-operated safety relief valves (POSRVs) has been evaluated. The SCDAPRELAP5 results have shown that the pressurizer surge line broke before the reactor vessel rupture failure, but a containment bypass did not occur because steam generator U tubes did not break. The intentional depressurization of the RCS using POSRV was effective for the DCH prevention at a reactor vessel rupture. (author)

A Dynamic Programming based method for optimizing power system restoration with high wind power penetration

DEFF Research Database (Denmark)

Hu, Rui; Hu, Weihao; Li, Pengfei

2016-01-01

and relatively low cost. Thus, many countries are increasing the wind power penetration in their power system step by step, such as Denmark, Spain and Germany. The incremental wind power penetration brings a lot of new issues in operation and programming. The power system sometimes will operate close to its...... stable limits. Once the blackout happens, a well-designed restoration strategy is significant. This paper focuses on how to ameliorate the power system restoration procedures to adapt the high wind power penetration and how to take full advantages of the wind power plants during the restoration....... In this paper, the possibility to exploit the stochastic wind power during restoration was discussed, and a Dynamic Programming (DP) method was proposed to make wind power contribute in the restoration rationally as far as possible. In this paper, the method is tested and verified by a modified IEEE 30 Buses...