1,721,002 research outputs found
Summary on collection and analysis of component failure data from fusion machine system operating experience
No full textThe present report gives a summary of data collection, analyses and reliability parameters related to failures occurred in fusion machines, with emphasis on the Joint European Torus (JET) operation experience. Data from the Tritium Laboratory of FZK Karlsruhe TLK were also collected and analysed.
Those activities were done, from 2001 to 2006, in the frame of the EFDA JET Fusion Technology tasks (JWO-FT-5.4, JW3-FT-5.13, JW5-FT-5.19) of the European Fusion Technology Programme.
The JET the data collection and the corresponding reliability analyses were related to the Vacuum System (VS), the Active Gas Handling System (AGHS), the Neutral Beam Injectors system (NBI), the Power Supply system (PS), and the JET Ion Cyclotron Resonant Heating system (ICRH).
Several thousands of components have been considered, in total, with their corresponding operation life. Few hundreds of failures/malfunctioning related to those components have been identified and classified. Data collection was based on a number of sources specific to the plant, including: operation records (e.g. electronic database, hand-written logbooks), incident investigation reports, maintenance and repair records/database, annual and technical reports, and plant personnel interviews.
Reliability parameters such as failure rate and failure probability on demands, with the corresponding standard error, lower and upper limits of the 90% confidence interval, have been calculated. As a result of the work, practical information arisen from the experience gained operating the different systems, were get out too.
More details about the overall activity are included in various ENEA reports and papers, listed in references of this report.
Statistical data are recorded on the “Fusion Component Failure Rate Database”, that is included in the frame of the International Energy Agency (IEA) Agreement on the Environmental, Safety and Economic Aspects of Fusion Power (IEA ESE), precisely, under Task 5 of the IEA ESE
The work was possible thank to the strong collaboration with the staffs of the different JET systems considered and the TLK and to the support of the EFDA-CSU
JET data collection on component malfunctions and failures of Ion Cyclotron Resonant Heating ICRH system
No full textThe overall objective of this task of JET Fusion Technology Task Force is to develop a fusion specific data collection (i.e. component failure database) with data coming out from operating experiences gained in the Joint European Torus (JET). The activity is related to JET Ion Cyclotron Resonance Heating (ICRH) system and it is the extension of the previous activities, which interested firstly Vacuum and Active Gas Handling systems, then the Coil and NBI Power Supply system.
Alarms/Failures and malfunctions occurred in the years of operations from March 1996 to November 2005, including information on failure modes and, where possible, causes of the failures, have been identified. Moreover, also data related to crowbar events have been collected.
About 3400 events classified as alarms or failures related to specific components or sub-systems were identified by analysing the 25 hand-written logbooks made available by the ICRH operating staff.
Information about the JET pulses in which the ICRH system was operated have been extracted from 20 hand written tick sheets covering the period from March 1996 to middle May 2003 and electronic tick sheets covering the period from May 2003 to November 2005. It results that the ICRH was operated during about 12000 plasma pulses.
Main statistical values, such as rates of alarms/failures and corresponding standard errors and confidence intervals, have been estimated. Failure rates of systems and components have been evaluated both with regard to the ICRH operation pulses and operating days (days in which at least one ICRH module was requested to operate). Failure probabilities on demand have been evaluated with regard to number of pulses operated.
The Report is issued with Four Appendixes (A, B, C and D). The Appendix A is dedicated to general data collection, classification and summary statistical analysis at ICRH system and ICRH module level; the Appendix B is dedicated to details on failure data (based on data collected from ICRH logbooks); the Appendix C is dedicated to detailed statistical and Reliability analysis from both at ICRH system level, down and at ICRH component/part level; the Appendix D gives the full list of data collected from the ICRH logbooks and tick sheets. The Appendixes A, B and C are distributed together with the Report, while the Appendix D will be distributed in a restricted form to people directly involved in JET operations. People interested in Appendix D can ask authors or EFDA CSU at JET
ASDEX Upgrade operating experience: statistical analysis on ECRH system failure
No full textThe study is set in the frame of an overall activity for collection and analysis of data coming from existing experience in different fusion machines. Particularly, in Europe, JET, Tore Supra and ASDEX Upgrade (AUG) facilities have been investigated.
This Report is dedicated to statistical analysis on failures occurred operating the AUG electron cyclotron resonance heating (ECRH) system. Information on failures have been collected by AUG team. The ENEA deliverable was dedicated to perform statistical evaluations on data collected.
Mean Failure Probabilities on Demand have been evaluated for the single gyrotrons, the two AUG ECRH groups (a couple of gyrotrons) and globally for the overall AUG ECRH system
DATA COLLECTION ON COMPONENT MALFUNCTIONS AND FAILURES OF JET ICRH SYSTEM
No full textThe objective of the activity was to collect and analyse data coming out from operating experiences gained in the Joint European Torus (JET) for the Ion Cyclotron Resonance Heating (ICRH) system in order to enrich the data collection on failures of components used in fusion facilities
Analysis of the ICE Experimental Tests Using the ECART Code
No full textIn the present paper the work performed to validate the ENEL/EDF ECART code on the base of a series of experimental tests performed in the Japanese ICE facility is presented. This activity has been carried out in the general framework of the validation phase of the ECART code, initially developed for integrated analysis of severe accidents in LWRs, for its application on incidental sequences related to fusion plants. The ICE facility consists of the cylindrical vacuum vessel, at horizontal axis (900. mm of external diameter and 600. mm length), the boiler, the blow-down tank and the corresponding piping and valves. The vessel has heat plates to maintain the required wall temperatures and initially contains dry air at a sub-atmospheric pressure of about 100. Pa. The employed ECART code full-couples the aerosol-vapour transport phenomena with thermal-hydraulics and chemical equilibrium. For the present work purposes, due to the ICE tests characteristics, only the thermal-hydraulic code section was activated and the dry aerosol or the chemical equilibrium modules were not employed. Two different conclusions have been highlighted by the work. The first one, being the main goal of the work, is related to the assessment of the ECART code in experimental conditions relevant for the future fusion reactors, against the traditional LWRs assessment previously performed for this code. The second one is related to the evaluation of the ICE experimental tests
IFMIF Preliminary Safety Analysis Report: Chapter 7 on Safety Analysis
No full textA Preliminary Safety Analysis Report (PSAR) has to be prepared for the International Fusion Materials Irradiation Facility (IFMIF) to address all the safety issues for the facility.
Clearly, many safety issues are related to the site where the facility will be built, but in this phase, because IFMIF site has not been yet decided, a generic site has to be considered in this report.
By Contract EFDA/04-1188 ENEA was committed to produce two Sections of the IFMIF PSAR:
• Chapter 2 - Safety design
To give a description of the IFMIF facility known to date from a safety point of view and to identify the safety functions and design requirements for each safety system.
• Chapter 7 - Safety analysis
This Report covers the material to be inserted as Chapter 7 of the IFMIF PSAR
COLLECTION AND ANALYSIS OF COMPONENT FAILURE DATA FROM JET SYSTEMS
No full textObjective of the on going activity is to develop a fusion specific component failure database with data coming from operating experiences gained in various fusion laboratories. The activity started since 2001 with the study of the Joint European Torus (JET) Vacuum (VS) and Active Gas Handling Systems (AGHS). Two years later the Neutral Beam Injectors (NBI) and Power Supply (PS) systems were considered and, in this last year the Ion Cyclotron Resonant Heating (ICRH) system is under evaluation.
Number of failures/malfunctions occurred in the years of operations, failure modes and, where possible, causes and consequences of the failures, were identified, as well as whole sets of components which the anomalies are related to. Components were classified and counted in order to find out amount of similar components, related total operating hours and related demands to operate (for components operating in intermittent way). Main reliability parameters (such as failure rate and corresponding standard errors and confidence intervals) associated to the components were estimated too.
In this paper results obtained for the NBI and PS will be presented in detail, as well as an overview of the main data estimated for all the systems.
As sample of the information that will be reported, we can mention that about one hundred failures were identified since the beginning of operations up to March 2004 for the NBI mechanical components installed in the two NBI boxes. For a NBI Unit of 8 PINIs per Unit, failure rates of 1.7E-4/h of full operating day (16 h/day) and 7.1E-2/h of pulses were estimated, while the failure probability on demand results 7.6E-5/pulse.
About 1000 failures and malfunctions were identified in the period January 1997 - May 2003 for the Coil PS systems, while for the NBI PS systems the identified troubles were about 900. Generic malfunctions, such as “Alert Alarm” or “Erratic Alarm” and “Failure to preset” the systems to operate, have been differentiated from troubles related to “Failure to operate” or “Spurious operation” of the systems. When possible, failures of low level components (e.g.: circuit breakers, solid state devices, capacitors, Instrumentation and Control devices, etc.) have been identified by the specific failure modes.
It has to be highlighted that component failure rates here evaluated are:
• one of the most consistent set of data in the field of fusion facilities, both for amount of components treated and for total number of operating hours;
• very useful in support of safety assessment and for availability/reliability analyses of fusion machines/plants
JET Operating Experience: Global analysis of tritium plant failure
No full textThe scope of the work was to build up an overall data collection about the existing experience on the performances and management of the JET tritium system. Particularly:
• Update the analysis performed in 2002 on data related to JET Active Gas Handling System (AGHS) failures, considering last information on failures occurred in the AGHS between September 2002 and September 2006. The information investigated on failures/malfunctions concern the identification of failed components, failure modes and, where possible, causes and consequences of the failures. To perform statistical analysis, the whole sets of components, which the failures/malfunctions are related to, have to be also identified. Components have been classified and counted in order to find out amount of components, related operating hours and, related demands to operate (for components operating in intermittent way). Main reliability parameters, (such as the failure rate and the corresponding standard errors and confidence intervals), associated to the components have been estimated.
• Analyze in more detail the most significant failures considering the unavailability of components, the maintenance, the possible impact on doses to the workers, the possible environmental releases related to the maintenance activities.
About 460 failures/malfunctions on a set of more than 6200 components, operating for about 215,000,000 hours, have been pointed out since 1995 up to September 2006 for the AGHS.
Failure rates here evaluated are in very good agreement with the corresponding ones existing in literature for similar applications (e.g.: nuclear power plants). The data here reported could be very useful to evaluate reliability parameters in support of safety assessment and for availability/reliability analyses of fusion machines/plants.
The investigation on significant maintenance operations highlights the very low consequences for workers in terms of worker doses and the negligible effects on environmental releases
Collection and analysis of component failure data from JET systems: neutral beam injectors and power supply
No full textObjective of the on going activity is to develop a fusion specific component failure database with data coming from operating experiences gained in various fusion laboratories. The activity started since 2001 with the study of the Joint European Torus (JET) Vacuum (VS) and Active Gas Handling Systems (AGHS). Two years later the Neutral Beam Injectors (NBI) and Power Supply (PS) systems were considered and, in this last year the Ion Cyclotron Resonant Heating (ICRH) system is under evaluation.
Number of failures/malfunctions occurred in the years of operations, failure modes and, where possible, causes and consequences of the failures, were identified, as well as whole sets of components which the anomalies are related to. Components were classified and counted in order to find out amount of similar components, related total operating hours and related demands to operate (for components operating in intermittent way). Main reliability parameters (such as failure rate and corresponding standard errors and confidence intervals) associated to the components were estimated too.
In this paper results obtained for the NBI and PS are presented in detail, as well as an overview of the activit
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