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 ...

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...

Thermodynamic accident analyses have been performed with computer simulation models to investigate core heatup sequences, sensitivity analyses, power variations, anticipated transients without scram, and core displacement considerations for probabilistic ...

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 ...

Structural analyses of the Watts Bar, Maine Yankee and Bellefonte containment structures were performed as part of the Severe Accident Sequence Analysis (SASA) program. The objective of these analyses was to obtain realistic estimates of the ultimate pres...

Boiling water reactor severe accident sequence studies are being carried out using Browns Ferry Unit 1 as the model plant. Four accident studies were completed, resulting in recommendations for improvements in system design, emergency procedures, and operator training. Computer code improvements were an important by-product.

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 pote...

As part of Sandia National Laboratories' Severe Accident Sequence Analysis (SASA) Program, structural analyses of the Watts Bar, Maine Yankee, and Bellefonte containment structures were performed with the objective of obtaining realistic estimates of thei...

The document contains the appendices for the accident sequence analyses of internally initiated events for the Surry Nuclear Station, Unit 1. This is one of the five plant analyses conducted as part of the NUREG-1150 effort by the Nuclear Regulatory Commi...

In support of the US Nuclear Regulatory Commission (NRC) Accident Management Research Program, a methodology has been developed for identifying the plant information needs necessary for personnel involved in the management of an accident to diagnose that an accident is in progress, select and implement strategies to prevent or mitigate ...

In this paper, a simple analytical code, QUASAR, is developed to analyze the phenomena related to severe subassembly accidents, such as a total instantaneous blockage event for a subassembly inlet. The code models failed and neighboring subassemblies, focusing mainly on the thermal consequences and the propagation potential of the accidents. The prediction ...

... Page 18. The accident data analyses developed by computer and submitted previously and separately to the monitoring agency showed accident ...

Probabilistic risk assessment (PRA) analyses have indicated the transient-initiated loss of vessel-water injection (TQUV sequence) to be a dominant accident scenario for BWR plants. The PRA studies assumed the low-capacity injection systems to be unimportant in severe accidents. The results of a Severe ...

The technology of thermal hydraulic aspects of the transition phase accident sequence in liquid metal fast breeder reactors has been reviewed. Previous analyses of the transition phase accident sequence have been reviewed and the current understanding of major thermal hydraulic phenomenology ...

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 the operator actions required by the EOIs of a reference BWR plant and compared 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 ...

Specific sequences that may lead to core damage were analyzed for the Bellefonte nuclear plant as part of the U.S. Nuclear Regulatory Commission's Severe Accident Sequence Analysis Program. The RELAP5, SCDAP, and SCDAP/RELAP5 computer codes were used in t...

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 ...

Operator Action Event Trees for transient and LOCA initiated accident sequences at the Zion 1 PWR have been developed and documented. These trees logically and systematically portray the role of the operator throughout the progression of the accident. The documentation includes a delineation of the required operator response and the ...

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 preaccident systems ...

This paper describes recent analyses performed by the BWR Severe Accident Technology (BWRSAT) Program at Oak Ridge National Laboratory to estimate the release of debris from the reactor vessel for the unmitigated short-term station blackout accident sequence. Calculations were performed with the BWR Severe ...

Trade and sensitivity analyses (i.e. effects of: system upgrades; ... Sequence - Accident scenario. A path through the ESD from initiator to a bad end state ...

The guidelines were prepared to assist the Consumer Product Safety Commission in the development of generic safety standards. This development is based on conceptual models of product hazard interactions and analyses of accident sequences, product cluster...

As part of Sandia National Laboratories' Severe Accident Sequence Analysis (SASA) Program, structural analyses of the Watts Bar, Maine Yankee and Bellefonte containment structures were performed with the objective of obtaining realistic estimates of their...

The Reactor Safety Study Methodology Applications Program (RSSMAP) conducted risk analyses of four light water reactors. The plants studied were each designed by a different US reactor vendor and are enclosed within three different containment types. Thes...

Safety is a crucial issue in densely sailed waterways. Traffic guidance systems (VTS) have proven to be valuable in this respect. The effectiveness of current systems and the benefits for improvements in navigation are addressed in this paper. Relevant incidents are analysed with a risk assessment tool (Accident Sequence Precursor ...

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 ...

with that letter, the Board believes that proper unmitigated or bounding accident analyses utilizing appropriately 19�22, 2002, visit to the site. Although the hazard and accident analyses for the CST DSA. Unmitigated Accident Analyses. The staff found that unmitigated ...

The report presents the results of the accident sequence analysis portion of Task Action Plan A-44, 'Station Blackout.' Along with a companion report by ORNL on onsite AC power systems, a technical basis for the resolution of Task A-44 is provided. Probab...

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...

... Accession Number : ADA146418. Title : Diving Accidents. Analyses of Underlying Variables. Descriptive Note : Interim rept.,. ...

... Accession Number : AD0730881. Title : Analyses of US Army Accident Data. Descriptive Note : Technical rept. Corporate ...

This paper presents the results and insights gained from MELCOR analyses of two severe accident scenarios, a Loss of Coolant Accident (LOCA) and a Station Blackout (TMLB) in Oconee, a Babcock Wilcox (B W) designed PWR with a large dry containment, and comparisons with Source Term Code Package (STCP) calculations of the same ...

A consistency review of accident analyses in US Department of Energy (DOE) safety, environmental, and emergency planning documents is presented. The range of and key differences in driving assumptions used in accident definition and frequency assessment, radiological source term generation, and atmospheric transport and fate modeling ...

This section of the Accident Model Document (AMD) presents the appendices which describe the various analyses that have been conducted for use in the Galileo Final Safety Analysis Report 2, Volume 2. Included in these appendices are the approaches, techniques, conditions and assumptions used in the development of the analytical models plus the detailed ...

This paper presents the results and insights gained from MELCOR analyses of two severe accident scenarios, a Loss of Coolant Accident (LOCA) and a Station Blackout (TMLB) in Oconee, a Babcock & Wilcox (B&W) designed PWR with a large dry containment, and comparisons with Source Term Code Package (STCP) calculations of the same ...

This section of the Accident Model Document (AMD) presents the appendices which describe the various analyses that have been conducted for use in the Galileo Final Safety Analysis Report II, Volume II. Included in these appendices are the approaches, techniques, conditions and assumptions used in the development of the analytical models plus the detailed ...

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 ...

The Committee on Interior and Insular Affairs conducted an informal review of the accident beginning on March 28, 1979 at the Three Mile Island Nuclear Power Plant. Officials of the Nuclear Regulatory Commission, plant operating personnel employed by General Public Utilities, and representatives of the reactor manufacturer, Babcock and Wilcox Company, related their activities ...

Technical Accomplishment Civil Helicopter Accident Analyses. SAFOR (SGH 6/2/98). Fatal Accidents: Cause/Estimated Cost (1990-1996) ...

IRRAS is a program developed for the purpose of performing those functions necessary to create and analyze a complete Probabilistic Risk Assessment(PRA). This program includes functions to allow the user to create event trees and fault trees, to define accident sequences and basic event failure data, to solve system and accident ...

Anticipated Transients Without Scram (ATWS) accident analyses make part of the Safety Analysis Report of the European Pressurized water Reactor (EPR), covering Risk Reduction Category A (Core Melt Prevention) events. This paper deals with three of the most penalizing RRC-A sequences of ATWS caused by mechanical blockage of the ...

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 current analytical ...

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, ...

Consistent methodology should be adopted in accident analyses sections of SARs. These accident sections should describe both consequence and risk from potential accidents that could occur in a facility being assessed. These analyses should consider three ...

This report presents the thermal-hydraulic design criteria (THDC) developed for the tungsten neutron source (TNS). The THDC are developed for the normal operations, operational transients, and design-basis accidents. The requirements of the safety analyses are incorporated into the design criteria, consistent with the integrated safety management and the ...

This 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 working with SASA analysts on the Browns Ferry Unit One anticipated transient without ...

SAS4A is a new code system which has been designed for analyzing the initial phase of Hypothetical Core Disruptive Accidents (HCDAs) up to gross melting or failure of the subassembly walls. During such postulated accident scenarios as the Loss-of-Flow (LOF) and Transient-Overpower (TOP) events, the relocation of the fuel plays a key role in determining the ...

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 and redistribution ...

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 concerned with determining ...

Thermodynamic accident analyses have been performed with computer simulation models to investigate core heatup sequences, sensitivity analyses, power variations, anticipated transients without scram, and core displacement considerations for probabilistic safety analyses (PSA) of small ...

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 severe accident management. Research by SASA analysts on the Browns Ferry Unit One ...

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 ...

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-...

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...

Feb 10, 2003 ... So as it effects everything from launch pads to analyses that are ... in a specific activity with the Columbia Accident Investigation Board. ...

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 ...

The temperature response of three generic surface models in each of three locations in an ice condenser containment building were calculated assuming a hydrogen deflagration event and using the HECTR code. The intent of using the three generic surfaces was to conservatively represent surfaces of various types of safety equipment. Analyses were performed for four ...

This report covers work to develop a methodology for analyzing precursors to both earthquake-initiated and fire-initiated accidents at commercial nuclear power plants. Currently, the U.S. Nuclear Regulatory Commission sponsors a large ongoing project, the Accident Sequence Precursor project, to analyze the safety significance of other ...

... However, a review of the accident analyses indicates that none of the accidents are significantly affected by the increase in the axial power peak ...

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 PuO2 (with Pu-238 ...

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 PuO2 (with Pu-238 ...

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 ...

This paper describes calculations performed to characterize the inherent safety of a 250-MW(t), 100-MW(e), pebble bed modular high temperature gas-cooled reactor (HTGR) design with vertical in-line arrangement (i.e., upflow core with steam generators directly above the core). A variety of postulated accident sequences involving combinations of loss of ...

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 ...

The analyses presented in this paper describe advanced methods of performing accident analyses by using finite element analysis. The models created to obtain solutions for these accident conditions are three-dimensional solid models which are solved in tr...

Accident Analyses and Technical Safety Requirements . The staff reviewed the development and documentation document. hazard and Accident Analyses-The Pantex DSAs have identified a comprehensive set of operational and accident analyses are described in detail, including ...

One of the most important safety design issues for a hydrogen production system coupling with a high-temperature gas-cooled reactor (HTGR) is to ensure reactor safety against fire and explosion accidents because a large amount of combustible fluid is dealt with in the system. The Japan Atomic Energy Research Institute has a demonstration test plan of a hydrogen production ...

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 reactivity feedbacks ...

Note: The review of applicable Hazard Analyses and Failure Mode and Effects Analyses can be used to identify accident contributors and accident scenarios. ...

... Accession Number : ADD103708. Title : FAILURE ANALYSES OF AIRCRAFT ACCIDENTS-PART II. Corporate Author : ...

... Accession Number : ADD100452. Title : FAILURE ANALYSES OF AIRCRAFT ACCIDENTS--PART III,. Corporate Author : ...

INEL conducted two ECCS analyses for Westinghouse Hanford. Both analyses will assist in the evaluation of proposed changes to the N Reactor Emergency Response Guide-B (ERG-B) Emergency Core System (ECCS) guideline. The analyses were a sensitivity study for reduced-ECCS flow rates and a mechanistically determined confinement steam ...

Consistent methodology should be adopted in accident analyses sections of SARs. These accident sections should describe both consequence and risk from potential accidents that could occur in a facility being assessed. These analyses should consider three general classes of ...

A study has been performed as part of the Severe Accident Risk Reduction Program (SARRP) to investigate the response of a particular pressurized water reactor with an ice-condenser containment (Sequoyah Unit 1) to postulated severe accidents. A detailed containment event tree for the Sequoyah plant has been devised to describe the various possible ...

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

Analyses of a PWR station blackout transient performed by EG and G Idaho in support of the US Nuclear Regulatory Commission's Severe Accident Sequence Analysis (SASA) Program are presented. The RELAP5 and SCDAP computer codes were used to calculate the ef...

Probabilistic risk assessment (PRA) analyses have indicated the transient-initiated loss of vessel-water injection (TQUV sequence) to be a dominant accident scenario for BWR plants. The PRA studies assumed the low-capacity injection systems to be unimport...

...demonstrated through either analysis, appropriate test programs...acceptable, as demonstrated by analysis, appropriate test programs...analytical tools used for safety analyses over a sufficient range of...conditions, and specified accident sequences, including...

In a cooperative effort among European and US analysts, an assessment of the comparative safety performance of metal and oxide fuels during accidents in a large (3500 MWt), pool-type, liquid-metal-cooled reactor (LMR) was performed. The study focused on three accident initiators with failure to scram: the unprotected loss-of-flow (ULOF), the unprotected ...

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...

the causes of an accident. A near collision analysed by the U.K. Department of Transport's Air Accident to analyse the operator�system interaction that can lead to accidents. 1.2 Outline Of The Paper This sectionThe Application Of Petri Nets To Represent And Reason About Human Factors ...

This paper reports on a cooperative effort among European and U.S. analysts, which is an assessment of the comparative safety performance of metal and oxide fuels during accidents in a 3500-MW (thermal), pool-type, liquid-metal-cooled reactor (LMR) is performed. The study focuses on three accident initiators with failure to scram: the unprotected ...

which are causal to the accidents. Technical risk analyses such as I outlined are complementary the interpretaion of the concepts \\accident", \\(accident) severity", \\hazard" and \\(hazard) latency". First, you have to say what you consider to be an accident. There are many de#12;nitions 1 ...

In this study, risk-significant pressurized-water reactor severe accident sequences are examined using MELCOR 1.8.5 to explore the range of fission product releases to the reactor containment building. Advances in the understanding of fission product release and transport behavior and severe accident progression are used to render best ...

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. ...

restrictive limits. Hazard and Accident Analyses. The staff identified several issues related to the hazard and accident analyses: � It is unclear how the hazards associated with MAR activities in the locked rooms Effective Dose Equivalent will not be exceeded for bounding postulated accident ...

A consistency review of accident analyses in US Department of Energy (DOE) safety, environmental, and emergency planning documents is presented. The range of and key differences in driving assumptions used in accident definition and frequency assessment, ...

A methodology of transient and accident analyses able to carried out calculations for all transients and accidents required to support operation and operation licensing of Angra-1 reactor reload, is presented. (Atomindex citation 18:076910)

of input data) would not serve to relax potential overconservatism in existing accident analyses. ! A fundamental aspect of the proposed approach to accident analyses is the identification of statistical an accident dose calculation methodology ("95 percentile methodology") being advanced for ...

Existing U.S. Army Accident Record data were analyzed, seeking relationships that would lead to recommendations for future routine analyses of such data which might help reduce the number and severity of accidents. Numerous computer analysis printouts wer...

Analysing i* System Models for Dependability Properties: The Uberlingen Accident Neil Maiden1 to analyse the Uberlingen air accident of 2002. Models were developed to describe the air traffic control and analysed to derive system properties that could be linked with some reported causes of the ...

As part of Sandia National Laboratories' Severe Accident Sequence Analysis (SASA) Program, structural analyses of the Watts Bar, Maine Yankee, and Bellefonte containment structures were performed with the obtective of obtaining realistic estimates of their ultimate static pressure capacities. The Watts Bar investigation ...

The THALES-2 code is an integrated severe accident analysis code developed at the Japan Atomic Energy Research Institute in order to simulate the accident progression and transport of radioactive material for probabilistic safety assessment (PSA) of a nuclear power plant. As part of a level 3 PSA being performed at JAERI for a 1,100 MWe BWR-5 with a ...

This document contains the internal event initiated accident sequence analyses for Peach Bottom, Unit 2; one of the reference plants being examined as part of the NUREG-1150 effort by the Nuclear Regulatory Commission. NUREG-1150 will document the risk of a selected group of nuclear power plants. As part of that work, this report ...

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 ...

Analyses of gamma and beta dose in selected regions in PWR and BWR containment buildings have been performed for a range of fission product releases from selected severe accidents. The objective of this study was to determine the radiation dose that safety-related equipment could experience during the selected severe accident ...

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

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 ...

A study has been performed as part of the Severe Accident Risk Reduction Program (SARRP) to investigate the response of a particular pressurized water reactor with a subatmospheric containment (Surry Unit 1) to postulated severe accidents. A detailed containment event tree for the Surry plant has been devised to describe the various possible ...