The inputs to the accident sequence evaluation include the system fault tree models and the event tree models. Each event tree sequence defines a unique accident sequence. The qualitative analysis of an accident sequence is ...

Information concerning the dominant accident sequences from twelve published probabilistic risk assessments (PRA) is cataloged in this report, which is published as a part of the Accident Sequence Evaluation Program (ASEP). The purpose of the report is to...

This report describes the results of safety-evaluation accidents selection by the probabilistic safety analysis method. The accident sequences following on nine initial events were analyzed by means of the event tree method. The occurrence probability (P)...

The report covers an accident delineation study undertaken to organize and evaluate the available information concerning LMFBR accident sequences and to identify key phenomenological and system-response uncertainties. The study can help provide a basis fo...

Information concerning the dominant accident sequences from twelve published probabilistic risk assessments (PRA) is cataloged in this report, which is published as a part of the Accident Sequence Evaluation Program (ASEP). The purpose of this report is to provide users of PRA information a ...

In support of the US Nuclear Regulatory Commission Accident Management Research Program, the availability of instruments to supply accident management information during a broad range of severe accidents is evaluated for a Boiling Water Reactor with a Mark I containment. Results from this ...

This paper highlights the interim results of ASEP. ASEP is one of many programs sponsored by the Nuclear Regulatory Commission (NRC) to study various aspects of severe core damage accidents. The results of ASEP will ultimately focus on identifying the most likely accident sequences and the high risk accident ...

...the Integrated Safety Analysis summary, remain available and reliable, in an accident sequence evaluated in the Integrated Safety Analysis, to perform their function...the Integrated Safety Analysis summary, remains available...nuclear criticality accident, and has been in...

This paper highlights the interim results of ASEP. ASEP is one of many programs sponsored by the Nuclear Regulatory Commission (NRC) to study various aspects of severe core damage accidents. The results of ASEP will ultimately focus on identifying the mos...

BS>In the design of the Polish high flux test reactor (30 MW) the evaluation of the possible sequences of accidents was performed and the maximum credible accident chosen. A failure of the pressure loop in the reactor core followed by the SPERT-type nuclear excursion and rupture of the remaining ...

In support of the US Nuclear Regulatory Commission (NRC) Accident Management Research Program, the availability of instruments to supply accident management information during a broad range of severe accidents is evaluated for a pressurized water reactor with a large dry containment. Results from this ...

HTGR safety evaluation included studies on fission product release; materials, chemistry, and instrumentation; structural evaluation; and analytical safety evaluation. LMFBR safety evaluation included studies on accident sequences, technical coordination of structural ...

An international analysis exercise has been organized to evaluate the ability of nuclear reactor severe accident computer codes to predict the TMI-2 accident sequence and core damage progression during the first 300 minutes of the accident. A required bou...

Preliminary accident analyses and radiological source term evaluations have been conducted for transuranic waste (TRUW) as part of the US Department of Energy (DOE) effort to manage storage, treatment, and disposal of radioactive wastes at its various sites. The approach to assessing radiological releases from facility accidents was ...

The volume presents the methodology and results of the integrated accident sequence analysis of the LaSalle Unit II nuclear power plant. Integrated results are obtained by merging all of the accident sequences' cut sets from the internal and external even...

Several safety evaluations for large High Temperature Gas Cooled Reactors (HTGR), using a Prestressed Concrete Reactor Vessel (PCRV) design, have concluded that Unrestricted Core Heatup Accidents (UCHA) present the most important severe accidents, resulting in the dominant source term. While the core thermohydraulic transients for such ...

The Events and Causal Factors (E and CF) chart (or diagram) depicts in logical sequence the necessary and sufficient events and causal factors for accident occurrence. It can be used not only to analyze the accident and evaluate the evidence during investigation, but also can help validate the accuracy of ...

A method is described for identification, preliminary evaluation, and screening of potential accident sequences leading to uncontrolled release of radioactive materials. Included is a procedure for estimating the risk sum of all identified sequences. In a...

The goal of this work is the investigation of the influence of different accident management strategies on the thermal-hydraulics in the containment during a Large Break Loss of Coolant Accident with a large containment leak from the beginning of the accident. The increasing relevance of terrorism suggests a closer look at this kind of ...

This report contains the Appendices for the Analysis of Accident Sequences and Source Terms at Waste Treatment and Storage Facilities for Waste Generated by the U.S. Department of Energy Waste Management Operations. The main report documents the methodology, computational framework, and results of facility accident analyses performed ...

The U.S. Nuclear Regulatory Commission has been conducting studies to evaluate the risk associated with steam generator tube failure during low probability severe accidents in pressurized-water reactors (PWRs) employing U-tube-type steam generators in par...

The purpose of this report is to describe the use of Probabilistic Risk (Safety) Assessment (PRA or PSA) at a Department of Energy (DOE) facility. PRA is a methodology for (i) identifying combinations of events that, if they occur, lead to accidents (ii) estimating the frequency of occurrence of each combination of events and (iii) estimating the consequences of each ...

This document presents a shortened version of the procedure, models, and data for human reliability analysis (HRA) which are presented in the Handbook of Human Reliability Analysis With emphasis on Nuclear Power Plant Applications (NUREG/CR-1278, August 1983). This shortened version was prepared and tried out as part of the Accident Sequence ...

... AVIATION ACCIDENTS, AIR TRANSPORTATION, HIGHWAYS, COAST GUARD, BOAT AND SHIP ACCIDENTS, MOTOR VEHICLE ACCIDENTS. ...

Until recently, the LMFBR safety research has been focused primarily on severe but highly unlikely accident, such as hypothetical-core-disruptive accidents (HCDA's), and not enough attention has been given to accident prevention, which is less severe but more likely sequence. The objective of the EBR-II ...

A review of accident analyses in recent US Department of Energy (DOE) Environmental Impact Statements (EISs) was conducted to evaluate the consistency among approaches and to compare these approaches with existing DOE guidance. The review considered several components of an accident analysis: the overall scope, which in turn should ...

Continuing code development work included improvements to the BLAST steam generator dynamics simulation for the Fort St. Vrain reactor and implementation of a simplified version of the core model CORTAP. Work continued on severe accident sequence analyses...

Work on postulated severe accident sequence code development and application continued both for the Fort St. Vrain and 2240-MW(t) lead plant designs. Initial experiments on high-temperature gas-cooled reactor (HTGR) fission-product release and transport w...

The document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during t...

The document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during t...

The document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during t...

The document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during t...

Many of the high-consequence accident sequences in the Reactor Safety Study (WASH-1400) involved containment failure by overpressurization. One way to relieve pressure and avoid containment failure is by venting of the containment atmosphere. The study undertook to develop some quantitative insight into the potential effect on public risk of venting and ...

This report provides the results of work carried out in support of the US Nuclear Regulatory Commission Accident Management Research Program to develop a technical basis for evaluating the effectiveness and feasibility of current and proposed strategies for boiling water reactor (BWR) severe accident management. First, the findings of ...

This paper briefly describes the results of work carried out in support of the US Nuclear Regulatory Commission Accident Management Research Program to evaluate the effectiveness and feasibility of current and proposed strategies for BWR severe accident management. These results are described in detail in the just-released report ...

This paper briefly describes the results of work carried out in support of the US Nuclear Regulatory Commission Accident Management Research Program to evaluate the effectiveness and feasibility of current and proposed strategies for BWR severe accident management. These results are described in detail in the just-released report ...

This report provides the results of work carried out in support of the US Nuclear Regulatory Commission Accident Management Research Program to develop a technical basis for evaluating the effectiveness and feasibility of current and proposed strategies for boiling water reactor (BWR) severe accident management. First, the findings of ...

This report identifies and evaluates accident management strategies that are potentially of value in maintaining containment integrity and controlling the release of radioactivity following a severe accident at a pressurized water reactor with an ice-condenser containment. The strategies are identified using a logic tree structure ...

A limited review is performed of the Severe Accident Risk Assessment for the Limerick Generating Station. The review considers the impact on the core-melt frequency of seismic- and fire-initiating events. An evaluation is performed of methodologies used for determining the event frequencies and their impacts on the plant components and structures. ...

Severe accident management can be defined as the use of existing and/or alternative resources, systems and actors to prevent or mitigate a core-melt accident. For each accident sequence and each combination of severe accident management strategies, there ...

A strategy has been developed for systematically addressing and handling the hazards posed by a transportation accident involving hazardous materials. The Accident Management Orientation Guide presents this system as a logic sequence of events in a color-...

Probabilistic Risk (Safety) Assessment (PRA or PSA) is an analytic methodology for identifying the combination of events that, if they occur, lead to accidents. Accidents are defined as those events causing loss or injury to people, property, or the environment. PRA also provides a method for estimating the frequency of occurrence of each combination of ...

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 ...

An integrated risk-based approach has been developed to address the human health risks of radiological and chemical releases from potential facility accidents in support of the U.S. Department of Energy (DOE) Environmental Restoration and Waste Management (EM) Programmatic Environmental Impact Statement (PEIS). Accordingly, the facility accident analysis ...

As a part of the overall effort undertaken by Brookhaven National Laboratory (BNL) to review the GESSAR-II probabilistic risk assessment, an independent containment performance evaluation was performed using the containment event tree approach. This evaluation focused principally on those accident sequences which ...

This volume presents the results of the initiating event and accident sequence delineation analyses of the LaSalle Unit II nuclear power plant performed as part of the Level III PRA being performed by Sandia National Laboratories for the Nuclear Regulatory Commission. The initiating event identification included a thorough review of extant data and a ...

Thermal-mechanical analysis of a fuel pin is an essential part of the evaluation of fuel behavior during hypothetical accident transients. The FSTATE code has been developed to provide this required computational ability in situations lacking azimuthal symmetry about the fuel-pin axis by performing 2-dimensional thermal, mechanical, and fission gas release ...

The Accident Sequence Precursor Program reviews licensee event reports of operational events that have occurred at LWRs to identify and categorize precursors to potential severe core-damage accidents. Accident sequences considered in the study are those associated with inadequate core cooling. ...

This study was conducted at the request of the USDOE/AL Dynamic Balancer Project Team to develop a set of representative accident sequences initiated by rapid seizure of the spindle shaft of the Schenck dynamic balancing machine used in the mass properties testing activities in Bay 12-60 at the Pantex Plant. This Balancer is used for balancing reentry ...

As part of the Severe Accident Sequence Analysis (SASA) program of the Nuclear Regulatory Commission (NRC), threats to containment and ways in which operators can help preserve containment integrity during severe accidents are examined. Severe accidents a...

The report describes a human factors research project performed to: (1) support the Severe Accident Sequence Analysis (SASA) program and (2) develop a descriptive model of operator response in accident management. The first goal was accomplished by workin...

An integrated risk-based approach has been developed to address the human health risks of radiological and chemical releases from potential facility accidents in support of the U.S. Department of Energy (DOE) Environmental Restoration and Waste Management (EM) Programmatic Environmental Impact Statement (PEIS). Accordingly, the facility accident analysis ...

Accident management strategies that have the potential to maintain containment integrity and control or mitigate the release of radioactivity following a severe accident at a boiling water reactor with a Mark 2 type of containment are identified and evaluated. The strategies are referred to as containment and release strategies. Using ...

The leakage behavior of containments beyond design conditions and knowledge of failure modes is required for evaluation of mitigation strategies for severe accidents, risk studies, emergency preparedness planning, and siting. These studies are directed towards assessing the risk and consequences of severe accidents. An ...

A review of the Oconee-3 Probabilistic Risk Assessment (OPRA) was conducted with the broad objective of evaluating qualitatively and quantitatively (as much as possible) the OPRA assessment of the important sequences that are ''externally'' generated and lead to core damage. The review included a technical assessment of ...

Changes in the US NRC Accident Sequence Precursor program methods since the initial program evaluations of 1969-81 operational events are described, along with insights from the review of 1984-85 events. For 1984-85, the number of significant precursors was consistent with the number observed in 1980-81, dominant ...

A General Electric Boiling Water Reactor (BWR3) with a Mark I containment has been evaluated as part of Task Action Plan A-45, ''Decay Heat Removal Requirements.'' Probabilistic risk assessment models were constructed to determine the dominant internal, randomly initiated accident sequences and ...

This report documents the methodology, computational framework, and results of facility accident analyses performed for the U.S. Department of Energy (DOE) Waste Management Programmatic Environmental Impact Statement (WM PEIS). The accident sequences potentially important to human health risk are specified, their frequencies are ...

The Probabilistic Safety Assessment (PSA) includes the actions of the operator like elements in the set of the considered protection performances during accident sequences. Nevertheless, its impact throughout a sequence is not analyzed in a dynamic way. In this sense, it is convenient to make more detailed studies about its importance ...

This study developed a set of dominant accident sequences that could be applied generically to domestic commercial PWRs as a standardized basis for a probabilistic seismic risk assessment. This was accomplished by ranking the Zion 1 accident sequences. The pertinent PWR safety systems were compared on a ...

This paper presents a new approach for developing and assessing severe accident management strategies under uncertainty in nuclear power plants. The strategy of flooding the reactor cavity during the TMLB{prime} sequence as a means to prevent vessel breach is used as an example. The modeling of complex decision problems, such as those encountered in severe ...

The Light-Weight Radioisotope Heater Unit (LWRHU) Final Safety Analysis Report (FSAR), Volume 2, Accident Model Document (AMD) describes potential accident scenarios during the Galileo mission and evaluates the response of the LWRHUs to the associated accident environments. Any resulting source terms, consisting of ...

The Light-Weight Radioisotope Heater Unit (LWRHU) Final Safety Analysis Report (FSAR), Volume 2, Accident Model Document (AMD) describes potential accident scenarios during the Galileo mission and evaluates the response of the LWRHUs to the associated accident environments. Any resulting source terms, consisting of ...

An assessment of many potential HFIR severe accident phenomena was conducted during the HFIR design effort, and many severe accident mitigating features were designed into the plant. These evaluation typically incorporated a bounding'' or highly conservative analysis approach and employed tools and techniques ...

This document contains the accident sequence analysis of internally initiated events for Grand Gulf, Unit 1 as it operates in the Low Power and Shutdown Plant Operational State 5 during a refueling outage. The report documents the methodology used during the analysis, describes the results from the application of the methodology, and compares the results ...

Gap conductance is a significant factor affecting the stored energy in a fuel rod at the beginning of a hypothetical accident sequence, as well as the thermal and mechanical response of the fuel rod during the accident. Additional well-characterized experimental results are needed to evaluate and improve the ...

A historic meeting was held Aug. 25-29, 1986, in Vienna, Austria. A delegation of U.S.S.R. experts presented detailed information on the design characteristics of the RBMK-1000 type of reactor and their evaluation of all aspects of the Chernobyl accident, including causes, events, measured releases, mitigation efforts, response measures taken, atmospheric ...

In the analysis of degraded core accidents, the two major sources of pressure loading on light water reactor containments are: steam generation from core debris-water thermal interactions; and molten core-concrete interactions. Experiments are in progress at BNL in support of analytical model development related to aspects of the above containment loading mechanisms. The work ...

The Accident Sequence Precursor (ASP) Program at ORNL analyzed about 14.000 Licensee Event Reports (LERs) filed by US nuclear power plants 1987--1993. There were 193 events identified as precursors to potential severe core accident sequences. These are reported in G/CR-4674. Volumes 7 through 20. Under the NRC ...

This paper describes and evaluates operational experiences with the Accident Response Mobile Manipulation System (ARMMS) during simulated accident site salvage operations which might involve nuclear weapons. The ARMMS is based upon a teleoperated mobility...

The impact on society of the Chernobyl accidents is assessed. The situation prior to Chernobyl with respect to regulations of radiation protection against the consequences of a major accident is considered. The development of the recommendations and regul...

This work presents a quantitative assessment of the impact that the emergency operating instructions (EOIs) of operating nuclear power plants may have on the frequency of severe accident sequences. Frequencies of such sequences were calculated based on th...

The current state of knowledge with respect to the analysis of postulated accident sequences in fast breeder reactors, as well as some implications to fast reactor design, are reviewed. The accidents considered include loss of coolant flow and transient overpower, both with a postulated failure to scram. The associated ...

... HUMAN), *AVIATION ACCIDENTS, *TOXICOLOGY, *ALCOHOLS, *ALCOHOLISM, *DRUG ABUSE, *DRUG ADDICTION, TEST AND EVALUATION ...

the gate chamber. The access shaft provides vertical access to the gates. Accident assessment. The evaluation of the nature, severity, and impact of an accident. Dam operating...

This report describes analyses of the response of a Pressurized-Water Reactor at the Zion Plant to hypothetical core-meltdown sequences. The analyses consider the progression of core meltdown, containment response, and consequences to the public for many specific accident sequences within the categories of Loss of Coolant ...

Since 1980, a series of accident studies concerning the Boiling Water Reactor (BWR) - MARK I containment plant design have been conducted by the Severe Accident Sequence Analysis (SASA) program at the Oak Ridge National Laboratory (ORNL). The SASA program is sponsored by Containment Systems Research Branch, Division of ...

This report identifies and evaluates accident management strategies that are potentially of value in maintaining containment integrity and controlling the release of radioactivity following a severe accident as a pressurized water reactor with large-dry containment. The strategies are identified using a logic tree structure leading ...

Mar 30, 2011 ... Sequence of Major Events of the Challenger Accident. Image library of the STS- 51L Challenger mission at Johnson Space Center. ...

Results of a preliminary safety evaluation of the Advanced Burner Test Reactor (ABTR) pre-conceptual design are reported. The ABTR safety design approach is described. Traditional defense-in-depth design features are supplemented with passive safety performance characteristics that include natural circulation emergency decay heat removal and reactor power reduction by inherent ...

Studies and operating experience suggest that the risk of severe accidents during low power operation and/or shutdown (LP/S) conditions could be a significant fraction of the risk at full power operation. Two studies have begun at the Nuclear Regulatory Commission (NRC) to evaluate the severe accident progression from a risk ...

The Three Mile Island nuclear plant (TMI-2) was modeled using the Transient Reactor Analysis Code (TRAC-P1A) and a preliminary calculation, which simulated the initial part of the accident that occurred on March 28, 1979, was performed. The purpose of this calculation was to provide a better understanding of the system thermal-hydraulic and core thermal-mechanical response ...

An analysis of five anticipated transients without scram (ATWS) was conducted at the Idaho National Engineering Laboratory (INEL). The five detailed deterministic simulations of postulated ATWS sequences were initiated from a main steamline isolation valve (MSIV) closure. The subject of the analysis was the Browns Ferry Nuclear Plant Unit 1, a boiling water reactor (BWR) of ...

This paper presents a QRA-based approach for assessing and evaluating the safety of installations handling explosive substances. Comprehensive generic lists of immediate causes and initiating events of detonation and deflagration of explosive substances as well as safety measures preventing these explosions are developed. Initiating events and corresponding measures are ...

. Ergonomics specialist conducted ergonomics evaluations. Several recommendations were made to the employee # of Total Accidents # of OSHA Recordable Accidents # of Lost Time Accidents Accident Rate (Includes all accidents) OSHA Recordable Accident Rate ...

This book presents the papers given at a conference on the human factors engineering of nuclear power plants. Topics considered at the conference included human modeling, artificial intelligence, expert systems, robotics and teleoperations, organizational issues, innovative applications, testing and evaluation, training systems technology, a modeling framework for crew ...

A simplified model of heat transfer and chemical reaction has been adapted to evaluate the expected behavior of droplets containing unreacted Zircaloy and stainless steel moving through the containment atmosphere during postulated accidents involving direct containment heating. The model includes internal and external diffusive resistances to reaction. The ...

This paper describes the methodology used in a human reliability analysis (HRA) conducted during a quantitative hazard assessment of a nuclear weapon disassembly process performed at the Pantex plant. The probability of human errors during the disassembly process is an extremely important aspect of estimating accident-sequence frequency for nuclear weapons processing. The ...

This report describes the results of tests conducted on three different designs of full-size electrical penetration assemblies (EPAs) that are used in the containment buildings of nuclear power plants. The objective of the tests was to evaluate the behavior of the EPAs under simulated severe accident conditions using steam at elevated temperature and ...

An important goal of the US DOE reactor development program is to conceptualize advanced safety design features for a demonstration Sodium Fast Reactor (SFR). The treatment of severe accidents is one of the key safety issues in the design approach for advanced SFR systems. It is necessary to develop an in-depth understanding of the risk of severe accidents ...

A new approach is presented for evaluating the uncertainties inherent in severe accident management strategies. At first, this analysis considers accident management as a decision problem (i.e., applying a strategy compared with do nothing) and uses an influence diagram. To evaluate imprecise node probabilities in ...

As part of a Nuclear Regulatory Commission (NRC) research program to evaluate the impact of using mixed-oxide (MOX) fuel in commercial nuclear power plants, a study was undertaken to evaluate the impact of the usage of MOX fuel on the consequences of postulated severe accidents. A series of 23 severe accident ...

As part of the Severe Accident Risk Reduction Program, researchers at Sandia National Laboratories have constructed a group of containment event trees to be used in the analysis of key accident sequences for light water reactors (LWR) during postulated se...

A parameter study was carried out for the FRM and the KKE7 core; in this study the effect of the important parameters on the chronological accident sequence and the max. power that was reached was investigated for the startup accident as the limiting case...

The liberation of radioactive materials into various containment locations during a severe accident creates a radiation field that may have a significant impact on the accident progression. High radiation may not only impair the functioning of important e...

...sequence of events leading to the accident or incident, to the extent...the consequences of a launch accident, launch incident, reentry accident, reentry incident, or other...adopt preventive measures for avoiding recurrence of the event....

The Draft Waste Management Programmatic Environmental Impact Statement (WM PEIS) was released by the U.S. Department of Energy (DOE) for public comment on September 22, 1995. Prepared in accordance with the National Environmental Policy Act (NEPA), the Final WM PEIS is currently scheduled for release in late summer 1996. The Draft WM PEIS was published after about 3 years of effort to select and ...

A contrasted sample of accident and accident-free drivers was evaluated in detail in order to determine factors related to accident involvement. Collected information represented biographical and driving-related data, personality traits and attitudes, par...

The basis for securing nuclear safety is to prevent occurrence of accidents and to mitigate propagation of abnormal events or accidents to severe accidents. In practice, a nuclear power plant is designed and constructed so that abnormal events can be dete...

The report evaluates the adequacy of accident analyses in environmental impact statements for nuclear powerplants. It reviews the regulations and policies governing nuclear accident analyses in EISs, surveys the accident analyses in 149 EISs in 10 years, ...

In support of the U.S. Nuclear Regulatory Commission Accident Management Research Program, the availability of instruments to supply accident management information during a broad range of severe accidents is evaluated for a Boiling Water Reactor with a M...

The evaluation of the dose that a person received in a criticality accident can be difficult. Most accidents have occurred when the person was not wearing nuclear accident dosimetry and since the NRC no longer requires these dosimeters, future dose evalua...

Interventions or technologies developed to improve aviation safety often focus on specific causes or accident categories. Evaluation of the potential effectiveness of those interventions is dependent upon mapping the historical aviation accidents into tho...

... § 71.73 Hypothetical accident conditions. (a) Test procedures...Evaluation for hypothetical accident conditions is to be based... Tests for hypothetical accident conditions must be conducted...been assumed for criticality analysis, immersion under a head...

The idea of primary containment venting to prevent or mitigate the consequences from a severe accident is not new. Research has been conducted on filter effectiveness for over thirty years. United States production reactors have had containment filter systems and applications to commercial facilities have been studied over the same period. In Europe, the countries with the ...

A Five-step methodology has been developed to evaluate information needs for nuclear power plants under accident conditions and the availability of plant instrumentation during severe accidents. Step 1 examines the credible accidents and their relationships to plant safety functions. Step 2 determines the ...

A Five-step methodology has been developed to evaluate information needs for nuclear power plants under accident conditions and the availability of plant instrumentation during severe accidents. Step 1 examines the credible accidents and their relationships to plant safety functions. Step 2 determines the ...

The current state of knowledge of fast breeder reactors is reviewed. The primary focus on the analysis of postulated accident sequences and the implications to fast-reactor design. The accidents considered include loss-of-collant flow and transient overpower, both with a postulated failure to scram. The associated ...

The paper discusses work conducted to: (1) support the severe accident sequence analysis of a nuclear power plant transient based on an assessment of operator actions, and (2) develop a descriptive model of operator severe accident management. Operator actions during the transient are assessed using qualitative and quantitative ...

In support of the Accident Sequence Precursor Program (ASP), the U.S. Nuclear Regulatory Commission (NRC), in conjunction with the Idaho National Laboratory (INL), in 1994 developed the Accident Sequence Precursor Standardized Plant Analysis Risk Model (A...

The course focuses on the probabilistic quantification of accident sequences and the link between accident sequences and consequences. Previous sessions in this series have focused on the quantification of system reliability (Session A) and the developmen...

For Zion, the following accident sequences were examined: station blackout with failure of auxiliary feedwater (TMLB'), loss of collant accidents (LOCA's) of various sizes inside containment, and the V-sequence interacing system LOCA which involves direct...

The paper will discuss work being conducted during this human factors review including: (1) support of the Severe Accident Sequence Analysis (SASA) Program based on an assessment of operator actions, and (2) development of a descriptive model of operator ...

CONTAIN is an integrated containment thermohydraulic and aerosol transport code. The choice of the Surry plant provides an opportunity to compare the CONTAIN calculations to those recently performed by Battelle Columbus Laboratories. The accident sequence...

A study is reported on the feasibility of the use of microwave dielectric heating to simulate the nuclear heat source in LMFBR 'transition phase' accident sequence volume-boiling simulation experiments. The adequacy of microwave heating is judged based up...

...Integrated safety analysis. (1) Each licensee...an integrated safety analysis, that is of appropriate... (iv) Potential accident sequences caused by...occurrence of each potential accident sequence identified...Integrated safety analysis team...

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 ...

In response to the damage which occurred during the Three Mile Island nuclear accident, the Nuclear Regulatory Commission (NRC) has implemented a Probabilistic Risk Assessment (PRA) program to evaluate the safety of nuclear power facilities during events with a low probability of occurrence. The PRA can be defined as a mathematical technique to identify ...

Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent ...

Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent ...

This paper describes the development process of the severe accident management guidelines (SAMG) for Units 3, 4, 5 and 6 of Ulchin Nuclear Power Plant. The units are Korean Standard Nuclear Power (KSNP) plant, 1000 MWe class pressurized water reactor (PWR) with two loops of primary coolant system. The severe accident management guidelines for the units ...

This reports documents work performed the NRC/RES Accident Management Guidance Program to evaluate possible strategies for mitigating the consequences of PWR severe accidents. The selection and evaluation of strategies was limited to the in-vessel phase of the severe accident, i.e., after the ...

A case study modeling the thrust reverser system (TRS) in the context of the fatal accident of a Boeing 767 is presented to illustrate the application of Probabilistic Safety Assessment methods. A simplified risk model consisting of an event tree with supporting fault trees was developed to represent the progression of the accident, taking into account the ...

The anatomy of the disaster at the BP refinery. Management and technical problems are highlighted. Factors that are common to many sites are emphasized. Animated sequences show the factors and there effects on the accident sequence.

A new methodology is developed for modeling a system's evolution to support decisionmaking on alternative actions which affect the system's evolution. The methodology is based upon the goal tree success tree method for hierarchal decomposition of the system's objective. The goal tree success tree structure is used to identify the system's objective and supporting functions and the events and ...

During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were ...

Traditionally, probabilistic risk assessments (PRAS) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Recent studies and operational experience have, however, implied that accidents during low power and shutdown could be significant contributors to risk. In response to ...

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 ...

... Accession Number : ADD814085. Title : Modeling, Measurement and Evaluation of Sequencing Flexibility in Manufacturing Systems. ...

The Accident Sequence Precursor (ASP) Program at ORNL analyzed about 14.000 Licensee Event Reports (LERs) filed by US nuclear power plants 1987--1993. There were 193 events identified as precursors to potential severe core accident sequences. These are re...

Risk analysis is being increasingly applied in the chemical process industries to assess health and safety problems and to improve loss-prevention capabilities. Many of the tools used in risk analysis to identify and evaluate accident sequences can also provide information for solving engineering and design problems. Systems-analysis ...

The methodology developed in support of the US Nuclear Regulatory Commission's (NRC's) evaluation of severe accident risks in NUREG-1150 is noted. This paper discusses the results. The principal technical analyses for NUREG-1150 were performed at Sandia National Labs. under the Severe Accident Risk Reduction Program ...

Results of a study for the identification of reactor core-melt accident mitigation measures at the Zion and Indian Point plants are summarized. Mitigation strategies have been identified that show promise of providing large reductions in consequences for specific accident sequences. However, without an overall risk analysis, it is not ...

The Savannah River Laboratory (SRL) human factors group has been developing methods for analyzing nuclear reactor operator actions during hypothetical design-basis accident scenarios. The SRL reactors operate at a lower temperature and pressure than power reactors resulting in accident sequences that differ from those of power ...

Appendix A contains information and details about the accident progression analysis. Appendix A.1 contains a detailed description and listing of the Accident Progression Event Tree (APET) and the binner that groups the outcomes of evaluating the APET. App...