bluuebunny/crossref_metadata_2025 huggingface dataset:
The BWR RPV Internals Management Program of the German NPP Gundremmingen, Units B and C: Results and Conclusions
Authors: Widera Martin
Published: August 2008

Due to the core shroud cracks reported from numerous BWRs including the German KWU type BWR Wuergassen, a RPV internals management program for the Gundremmingen NPP (KRB-II) has been initiated in 1994. Major steps and the main results of this program are presented. As an interim result, surface condition of the weld regions and controlled post weld heat treatment (PWHT) in order to reduce the residual stresses seem to play an important role for resistance to crack initiation and growth. To support these assumptions, results of related R&D projects of the German utilities (VGB) are presented.
High-Cycle Analytical Thermal Fatigue Tests on Pipe Structures
Authors: Stephan J. M. , Curtit F.
Published: August 2008

In 1998, a leak occurred in the main mixing zone of the residual heat removal systems (RHR) of the EDF CIVAUX nuclear plant unit 1. The crack is attributed to high-cycle thermal fatigue due to the fluid thermal turbulences. An research and development (R&D) program is now being conducted at EDF to understand the incident and to assess the risks of cracks in other mixing zones. This program includes thermal-hydraulic tests on mock-ups and their numerical interpretation, material testing in high-cycle fatigue, structure tests on mock-ups submitted to high-cycle thermal stresses and their interpretations, and developments in non destructive evaluations in the presence of crazing zones (thermal striping). After a brief presentation of the R&D program, the paper presents a new high-cycle thermal fatigue bench test, named INTHERPOL, for pipe structures. The thermal cycles consist of periodic controlled cold shocks by water sprays and hot shocks by infrared radiations on the inner surface of part of the structure. The structure under test, the water spray devices and infrared modules are inserted into a tank to allow constant control of the environment. The types of pipe structures tested include plain or welded structures and various industrial surface finishes. The first tests results and their numerical interpretations are presented.
Life Management of Reactor Coolant Piping — Probabilistic Calibration of Partial Safety Factors in Flaw Acceptance Criteria: Application to Cast Duplex Stainless Steel Components
Authors: Barthelet Bruno , Franco Christian , Bezdikian Georges , Le Delliou Patrick
Published: August 2008

The RSE-M Code provides rules and requirements for in-service inspection of the components of the French PWR power plant. The Code gives non mandatory guidance for analytical evaluation of flaws, comprising fracture mechanics analyses based on engineering methods, flaw acceptance criteria and codification of material characteristics. Based on a probabilistic calibration methodology, partial safety factors on the main random variables involved in flaw assessments (loading, crack size, yield strength and material toughness) are given in Appendix 5.5 of the Code for each category of operating conditions (A, C or D) and for the possible failure modes (ductile tearing or brittle fracture). These partial safety factors should be used with the material characteristics specified in Appendix 5.6 of the Code, to insure the consistency of the methodology. The criteria of the RSE-M Code have been implemented for the acceptance of generic flaws in cast duplex stainless steel elbows of the Reactor Coolant System. Statistical analyses of the mechanical properties of the base-metal have been carried out to get their characteristic values consistent with the Code criteria: • tensile properties comprising yield strength, ultimate tensile strength and non dimensional reference true stress - true strain curves taking into account thermal ageing, • value of the J-integral in the ductile regime at the onset of crack extension (J0.2 after 0.2 mm of crack extension), J-Δa curves in the ductile regime taking into account thermal ageing in the hot leg conditions, • fatigue crack growth rates. The results show that the aged cast duplex stainless steel elbows satisfy the Code criteria for each category of operating conditions.
Age-Related Degradation of Steam Generator Internals Based on Industry Responses to Generic Letter 97-06
Authors: Subudhi M. , Sullivan E. J.
Published: August 2008

This paper presents the results of an aging assessment of the nuclear power industry’s responses to NRC Generic Letter 97-06 on the degradation of steam generator internals experienced at Electricite de France (EdF) plants in France and at a United States pressurized water reactor (PWR). Westinghouse (W), Combustion Engineering (CE), and Babcock & Wilcox (B & W) steam generator models, currently in service at U.S. nuclear power plants, potentially could experience degradation similar to that found at EdF plants and the U.S. plant. The steam generators in many of the U.S. PWRs have been replaced with steam generators with improved designs and materials. These replacement steam generators have been manufactured in the U.S. and abroad. During this assessment, each of the three owners groups (W, CE, and B&W) identified for its steam generator models all the potential internal components that are vulnerable to degradation while in service. Each owners group developed inspection and monitoring guidance and recommendations for its particular steam generator models. The Nuclear Energy Institute incorporated in NEI 97-06, “Steam Generator Program Guidelines,” a requirement to monitor secondary side steam generator components if their failure could prevent the steam generator from fulfilling its intended safety-related function. Licensees indicated that they implemented or planned to implement, as appropriate for their steam generators, their owners group recommendations to address the long-term effects of the potential degradation mechanisms associated with the steam generator internals.
Managing Aging of Coatings for Nuclear Power Plant License Renewal
Authors: Miller Henry R.
Published: August 2008

Coatings are applied to structures and components in nuclear power plants, both inside and outside containment. The coatings applied to safety-related structures, systems, and components inside containment are classified a Service Level I Coating, and coating systems outside of primary containment, but which in the event of a failure could adversely affect the orderly and safe shutdown of the plant are classified a Service Level III coating. Weaknesses have been found in existing programs in regards to application of protective coatings for Service Level 1. This weakness is evident as blistering, cracking or peeling. For the extended period of operation, the licensee must demonstrate that in-place coating is qualified except for coatings shown on an Unqualified Coatings List; that the amount of unqualified coatings will not clog sump screens, strainers, or other safety-related equipment; and that coating assessment is being made at each refueling outage. This paper will discuss the elements of a good coating program for the period of extended operation to ensure that existing coating systems are qualified; and that unqualified and degraded coatings will not clog strainers, screens or other safety-related equipment.
Taking Advantage of Signal Processing for Lifetime Management
Authors: Gautier S. , Chaˆtellier L.
Published: August 2008

So as to detect and characterize potential defects in pipes, inspections are carried out. Should a defect be detected, one can be asked to prove the component still stands the mechanical constraints. Then, it is essential to characterize the defect, especially when the demonstration relies on mechanical calculus: the better the characterization, the better the mechanical assessment. Still, the characterization of the defect from the sole data is sometimes very difficult and the justification process can thus be dramatically jeopardized. In such cases, signal processing can be very helpful for the interpretation of the data and for the defect’s characterization. This paper is dedicated to the inspection of pipes with narrow beam X-ray imaging. For this application, the characterization of the defect is indeed very difficult. We show that the signal processing makes it possible to achieve a 3-D reconstruction of the component providing a characterization of the defects. Thus, the signal processing can turn out to be an essential step between measurement and mechanical calculus.
An Economic Assessment Methodology for Replacement of the Components of Nuclear Power Plant
Authors: Moonn Ho-Rim , Jang Changheui , Park Jun-Hyun , Jeong Ill-Seok , Kim Tae-Ryong
Published: August 2008

Generally, the economic assessments of the major component replacements of nuclear power plants (NPPs) have been carried out in deterministic ways. However, the deterministic assessments had difficulty in treating the input variables with uncertainties, and could result in erroneous decision. A method based on the probability theory would be a proper alternative to take into account the uncertainties in real world much precisely. In this paper, an economic assessment for replacement of an NPP component has been performed through the decision analysis adopting the probability theory. The major factors of the decision analysis are the selected alternative among various options, the results brought about from the selection, and the relative priority of the certain alternative compared to the others. A significant advantage of the decision analysis lies in processing the uncertainties and risks. The model of decision analysis could be built with influence diagrams and decision trees. In this paper, the optimal time of replacing “A” type of steam generator (SG) was determined using the decision analysis methodology. This methodology can be applied to the economic evaluations for replacements of major components of NPPs under the free competition of Korean power market of in the future.
Life Time Management: A Practical Approach of Nuclear Power Plants
Authors: Bartonicek Jaroslav , Metzner Klaus-Juergen , Schoeckle Friedrich
Published: August 2008

A comprehensive life time management has to take care of all safety and availability relevant components in nuclear power plants, with different intensity, of course. For instance, mechanical systems and components can be basically classified/ranked into three different groups: (1): The quality status of the components in this group has to be guaranteed on a pre-defined (high) level. (2): The quality status of the components in this group has to be maintained on its actual level. (3): Other components with no specific quality demands. Regarding the first group, integrity has to be guaranteed. Therefore it is necessary to monitor the possible root causes of degradation mechanisms during plant operation; thus the degradation effects can be assessed and — more important — controlled to maintain the safety standard on the demanded high level without any compromise. The monitoring of consequences of degradation mechanisms is being performed as an additional redundant measure. The requirements to maintain the quality status of the second group of components can be fulfilled by monitoring of the consequences of operational degradation mechanisms to be performed by preventive maintenance activities, in terms of tests, inspections and repairs, using either time dependant procedures or component condition orientated methods. For the third group of components, no preventive action is necessary. However, failures and malfunctions have to be assessed statistically to avoid a reduction of the required basic component quality. In the first two groups all safety relevant components and systems are included. Generally, aging management programs cover these two groups of components; life time management covers all of above groups. This paper concentrates on mechanical systems and components; it summarizes the practical approach to life time management as it is realized in German nuclear power plants. The application is discussed using dedicated examples.
Industry Survey of Risk-Based Life Management Practices
Authors: Speck Julian B. , Iravani Abdolreza T. M.
Published: August 2008

The application of risk-based life management practices has generated considerable interest in industry. Plant safety and availability can be demonstrably improved through the application of risk-based methods alongside good plant management practices. The needs for and the experience of risk-based plant life management however, vary greatly across industry sectors. The principles of risk-based methods are documented and many risk-based techniques are widely available, but the practical interpretation of the principles and the use of the most appropriate techniques are subjects of great debate. This paper will identify technical and organisational requirements to implement risk-based methods. As part of this paper, a questionnaire survey has been carried out among companies to gain better understanding of the reality of plant life management and the needs of plant operators. This survey indicates that the benefits of risk-based methods for inspection (RBI) and maintenance (RBM) optimisation are recognised by different industrial sectors. There appears to be a lack of established and documented uniform RBI/RBM policy or guidance for application throughout the industry sectors. There is also an indication of insufficient resources and training to implement risk-based methods. Development of risk-based techniques by a competent team and an integrated user-friendly software based on a sound methodology remain as key issues. A case study is described of the application of RBI to an oil refinery process unit.
A Logic Model Approach to Conceptual Design of a Scientific/Industrial Complex
Authors: Bott Terry F. , Eisenhawer Stephen W.
Published: August 2008

We demonstrate how the use of logic models and approximate reasoning can lead to more effective conceptual design of a large-scale scientific/industrial complex. A deductive model is used to describe the relationships between the mission of a complex, the tasks that are the concrete expressions of the mission, and the capabilities and resources that allow the mission to be carried out. This deductive logic model provides the formal basis for integrating these relationships into a conceptual design and provides a framework to express design options that are an essential part of the description of the complex. A decision model for choosing among the design options is constructed using approximate reasoning. This AR model uses forward-chaining inference models to emulate the types of reasoning used by experts. This approach allows the analyst to use both numerical data when available and the qualitative knowledge that forms much of the information base used in conceptual designs of new and innovative complexes.
Using QRA to Make Maintenance Trade-Off Decisions
Authors: Farquharson John A. , Choquette Francois
Published: August 2008

This paper discusses the concept of using quantitative risk assessment (QRA) techniques to make specific decisions regarding competing risks associated with specific maintenance policies. This paper is based on a project performed for a major international airline to assess the risk trade-off between a potential catastrophic event occurring during a maintenance procedure versus the possibility of inadvertently leaving a safety device in place following plane takeoff. The paper demonstrates the use of simplified event trees, human reliability analysis, and risk-based decision making.
Incorporating Total Quality Management Into Safety Program: General Approach
Authors: Blyukher Boris
Published: August 2008

An increasing number of articles in professional journals in safety field address the natural fit between safety and quality. As a group, safety professionals strive to improve organizational performance through application of loss control and safety management techniques. The total quality management (TQM) philosophy also emphasizes improvement of overall organizational performance via application of quality management concepts and techniques. This paper presents a conceptual model and framework for developing a comprehensive safety program with incorporating elements of TQM which contribute to potential hazards and accidents reduction. These methods are demonstrated on the example of safety program for Superconducting Super Collider Laboratory (SSC). The goal of this program is to analyze various components interfaces and interrelationships to ensure that they meet specified safety criteria. The proposed program is based on a proven managerial approach to provide timely documentation for design and operations associated with systems, facilities, and equipment. As a result of this program, provisions and actions for quality assurance, reliability, safety, and hazard prevention and control have been put in place to reduce all identifiable potential hazards to a low risk level.
Integrated Risk Evaluation for Probabilistic Safety Assessment Levels 1, 2, and 3 for Nuclear Power Plant Applications
Authors: Cho F. L.
Published: August 2008

This paper introduces a newly developed paradigm for performing an integrated risk evaluation using Probabilistic Safety Assessment (PSA) Levels 1, 2 and 3 results for nuclear power plant applications. This paradigm focuses on the issues of radionuclide release transport phenomena and source term determination from a severe nuclear reactor accident.
Risk-Based Maintenance: A New Vision for Asset Integrity Management
Authors: Montgomery Randal L. , Serratella Chris
Published: August 2008

This paper describes a holistic, risk-based approach to asset integrity management (AIM). The approach outlined in this paper is referred to as risk-based maintenance. This approach is based on proven risk assessment and reliability analysis methodologies, as well as the need to have appropriate management systems. Combining these tools and management systems provides a holistic approach to managing asset integrity, rather than a seemingly random application of analysis approaches and improvement initiatives. The information in this paper will benefit plant personnel interested in implementing an integrated AIM program or advancing their current AIM program to the next level.
Statistical Considerations for Determining Extent of Piping Inspections for RBI or API-570 Driven Inspections
Authors: Hobbs D. , Ku A. P.-D.
Published: August 2008

This paper outlines a method for calculating the number of inspection locations for process piping inspections. The method determines the number of piping inspection locations required for an inspection to detect a particular damage state within the confidence limits of the premised inspection’s reliability. It is intended to be used for piping inspections per API-570, “Piping Inspection Code” and in the application of risk-based inspection concepts presented in AP1-581, “Risk Based Inspection, Base Resource Document”. This method combines recognized inspection and piping engineering practices and random-field statistical tools to calculate the number of inspection locations in piping systems with probabilistic confidence level. This method has provisions for future applications when inspection data is known, or there is greater uncertainty in the distribution of the degradation or the reliability of the inspection data is different than those premised in this paper.
Applications of Risk-Based Decision-Making Tools for Process Equipment Maintenance
Authors: Montgomery Randal L. , Satterfield William C.
Published: August 2008

This paper explains a risk-based approach for analyzing process equipment that will help maintenance organizations improve system reliability and optimize maintenance resources. In addition, the approach provides a methodology for organizations to move from a prescriptive or compliance-based maintenance strategy to a risk-based maintenance strategy. The approach outlined is based on proven risk assessment and maintenance analysis tools, such as reliability-centered maintenance. The information in this paper will benefit maintenance professionals interested in optimizing maintenance resources.
Optimal Control of Performance Risk for Large Potentially Dangerous Systems (LPDS)
Authors: Timashev Sviatoslav A.
Published: August 2008

The paper considers the safety problem for large potentially dangerous systems (LPDS). Disruption of their normal operations may lead to casualties, ecological and property damage. Solution to the above problem is sought in the framework of risk control of LPDS during their normal operation, based on the principle of preventive actions. Risk is described as the product of conditional probability of failure and the overall consequences of such failure. Methods of brining down risk analysis problems to reliability problems are presented. They are based on the following: assessments of “cost of life” (as economic equivalent of casualty); simultaneous optimization of the LPDS and its safety subsystem (expansion of the object of optimization). Such an approach allows unification and merging of structural reliability theory and probabilistic risk analysis. A quantitative method of damage size (the first component of risk) assessment is described, based on computer modeling of a full group of scenarios of a structural failure developing into a full blown LPDS catastrophe. As a result of modeling, the destruction zones and the character, size and probabilities of all kinds of damage (casualties, ecological damage, loss of property) are assessed. It is proposed, as the main method of securing LPDS integrity and safety, to equip each LPDS with suitable monitoring/inspection/maintenance systems, designed as an instrument for controlling the second component of risk (conditional probability of failure), on the basis of a three-level (warning-alarm-failure) control policy. In the outlined format maintenance/repair is considered as optimal control of random degradation and renewal functions, interaction of which forms a certain regeneration process. Analysis of this process allows defining the optimal triggering levels of deterioration parameters or risk that minimize total expenditures of LPDS performance while ensuring its safety. The problem formulated above naturally embodies all existing maintenance methods (based on admissible performance time, rate of failure and on actual and prognosed system condition). Further, the problem of optimal cessation of performance is solved. It allows convoluting a multi-parameter problem into a one-parameter problem and defining the ultimate permissible level of conditional probability of failure. The described methods of risk analysis and control were used in residual lifetime monitoring systems for oil pumping aggregates and for main oil pipe line segments repair prioritization.
Failure Behavior of Piping Systems With Wall Thinning Under Seismic Loading
Authors: Nakamura Izumi , Otani Akihito , Shiratori Masaki
Published: August 2008

In order to investigate the influence of degradation on dynamic behavior and failure modes of piping systems, shaking table tests of 3-D piping models with degradation were conducted. The degradation condition induced in the piping models was about 50% full circumferential wall thinning at an elbow or elbows. By varying the induced parts in the piping model, 4 kinds of models were made for the shaking table tests. These models were excited under the same input acceleration until the models failed and caused leak of pressurized internal water. Through these tests, the change of the vibration characteristic and the process to failure of degraded piping models were obtained. The deformation of the piping models tended to concentrate on the degraded elbows, and therefore the damage concentrated to a weakest elbow in the piping models. The failure mode of the piping models was a low-cycle fatigue failure at the weakest elbow.
Failure Analysis of Thinned Wall Elbows Under Excessive Seismic Loading
Authors: Shiratori Masaki , Ochi Yoji , Nakamura Izumi , Otani Akihito
Published: August 2008

A series of finite element analyses has been carried out in order to investigate the failure behaviors of degraded bent pipes with local thinning against seismic loading. The sensitivity of such parameters as the residual thickness, locations and width of the local thinning to the failure modes such as ovaling and local buckling and to the low cycle fatigue damage has been studied. It has been found that this approach is useful to make a reasonable experimental plan, which has to be carried out under the condition of limited cost and limited period.
Developments of Seismic Design Code for High Pressure Gas Facilities in Japan
Authors: Shibata Heki , Suzuki Kohei , Ikeda Masatoshi
Published: August 2008

The Seismic Design Code for High Pressure Gas Facilities was established in advance of other industrial fields in 1982. Only exception was that for nuclear power plants. In 1995, Hyogoken Nanbu earthquake brought approximately 6,000 deaths and more than 100,000 M$ loss or property in Kobe area, Japan. This unexpected serious event enforced us that industrial facilities should pay to special considerations of their damages including ground failure due to the liquefaction. Their strong ground motions brought serious damages to urban structures in the area. Thus, the Seismic Design Code of the High Pressure Gas Facilities were improved to include 2 step design assessments, that is, Level 1 earthquake (operating basisearthquake, the probable strong earthquake in the service life of the facilities), and Level 2 earthquake (safety shutdownearthquake, the possible strongest earthquake with extremely low probability of occurrence). For Level 2 earthquake, the ground failure by possible liquefaction shall be taken into account. In regard to Level 1 earthquake, the system must be remained safety without critical damage after the earthquake, in addition to no leakage of “gas”. In regard to Level 2 earthquake, the required seismic performance is that peventing systems must be remained without gas leakage, and stable. It means a certain non-elastic deformation without gas leakage may be allowed. The High Pressure Gas Safety Institute of Japan has set up the Seismic Safety Promotion Committee to modify their code in advance of other industries, and continue to investigate more reasonable seismic design practice for more than 5 years. Andthe final version of the guideline has been established for the design practices both in Level 1 and Level 2 earthquakes. This paper explains the activities of the committee, their new design concepts and scope of applications.
A New Seismic Design Criteria of Piping Systems in High Pressure Gas Facilities
Authors: Inaba Makoto , Ikeda Masatoshi , Shimizu Nobuyuki , Watanabe Tetsuya
Published: August 2008

After the Great Hyogoken-nanbu Earthquake, “Seismic Design Code for High Pressure Gas Facilities of Japan” was amended. This amended code requires two step seismic assessments, that is, evaluation of Level 1 Required Seismic Performance for Level 1 Earthquake and that of Level 2 Required Seismic Performance for Level 2 Earthquake. Seismic design of piping systems is newly involved in the scope of the code. For Level 2 Earthquake, possible ground displacement due to liquefaction is taken into account. When ground displacement occurs, foundations of structures settle, laterally move or incline as a conseqence, and a piping system supported by independent foundation structures suffers from relative displacements between supporting points, which may exceed several tens of centimeters. The evaluation method of Level 1 Required Seismic Performance is specified in the amended code and that of Level 2 Required Seismic Performance is proposed in the guideline. The former evaluation is based on elastic design and the latter on elasto-plastic design. The propriety of design criteria of piping systems against ground displacement was confirmed by large deformation tests. This paper introduces seismic design criteria of piping systems in the amended code and the evaluation method of Level 2 Required Seismic Performance proposed in the guideline, and also reports the results on the large deformation tests.
Study on 3-D Measurement Method for Structural Dynamic Displacement in Shake Table Tests Using Image Processing
Authors: Fujita Satoshi , Furuya Osamu , Niitsu Yasushi , Mikoshiba Tadashi , Yamazaki Hiroaki
Published: August 2008

This study has been examined about a 3-dimensional measurement method suitable for a fracturing test of real scale model using shake table test, and has proposed the measurement system using image processing. Although this measurement system is based on a simple theory of measurement, it is a very convenient system which only requires to install the markers on the object structure and it can be considered as the most suitable measurement system to evaluate the complex 3-dimensional behavior of real scale structure. Fundamental hardware and software in measurement system has been constructed until now. Moreover, the fundamental dynamic measurement accuracy and effectiveness of the proposed measurement system has been confirmed from the shake table tests using the 5-storey building model in elastic region. This paper describes the dynamic measurement accuracy, the effectiveness of the proposed system and the evaluation for practical use from the results of shake table tests using the collapse building model and the wooden house model.
Development of Advanced Mechanical System for 3-D Full-Scale Earthquake Testing Facility
Authors: Watanabe Shintaro , Maekawa Kazuhiko , Tanaka Yasuyuki , Koike Akesi , Yamasaki Yukiharu
Published: August 2008

The largest 3-dimensional vibration test facility is being constructed in Japan’s Hyogo Prefecture. The objective of this facility is to assist the investigation on the process of the collapsing phenomena of a full-scale structure in an earthquake. This facility has a large size shaking table (15 m × 20 m), with a payload of 12 MN. Actuators are connected to the shaking table via 3-D links. In order to reduce the distortion of accelaration wave form, low friction tribo-elements are employed in the actuators; a hydrostatic bearing for rod supports, a pressure balanced seal for pistons, a floating ring seal for 3-dimensional joints. Since these elements are large and heavily loaded, the deformation of them are relatively large compared to the oil film gap in the elements and make design difficult. The paper exhibits the tribological performance of the actuators and joints.
Development of Numerical Dynamic Simulators for 3-D Full Scale Earthquake Testing Facility (Phase-2)
Authors: Kajii Shinichiro , Yasuda Chiaki , Yamashita Tosio , Okuda Yukihito , Hirai Jun , Ogawa Nobuyuki , Shibata Heki
Published: August 2008

The largest 3-dimensional vibration test facility is planning to build in Hyogo pref. The objectives of this facility are to investigate the process of the collapsing phenomena of a full-scale structure under the earthquake. At the design stage, it’s impossible to make sure the performance without the numerical simulation. Therefore, the mathematical simulation model was accurately constructed, and the simulation was performed. This paper describes as follows. (1) The modeling method of the 3-dimensional vibration test system. (2) The verification of the modeling method based on the measured data by using the prototype test facilities. (3) The verification results based on the condition of a collapsing phenomena of the full-scale building.
Feasibility Study of Tank Failure Test With “E-Defense”
Authors: Oka Shojiro , Kajiwara Kouichi , Itoh Tomohiro
Published: August 2008

After the 1995 Kobe earthquake in Japan, National Research Institute for Earth Science and Disaster Prevention started to construct a large-scale 3-D shaking table, called “E-Defense”. The facility is to be completed in 2005, and failure experiments of many kinds of structures are to be performed. As for a feasibility study of those experiments, a plan of a full-scale tank failure test was investigated. A steel cylindrical tank of 990m3 capacity was selected as a typical liquid storage tank. The height is about 15m and the diameter is about 10m. The total mass, with full of water, is about 1 MN (1,000 tonf). The tank is constructed on a steel frame structure for specimen handling and test facility protection, and set on the shaking table. To prevent facility failure due to a mass of water leakage, waterproof walls are necessary at the lower part of the frame. Ground motion recorded at the Kobe earthquake is applied to the shaking table, and elephant foot bulge buckling is expected to occur at the bottom portion of the tank. Through this preliminary planning, technical feasibility of tank failure tests was confirmed, and problems to be solved for actual planning were clarified.
Experimental Method Using the Inertial Loading Equipment by the Large Scale Shaking Table
Authors: Yamada Satoshi , Matsumoto Yuka , Yamaguchi Michio , Ogawa Nobuyuki , Wada Akira , Akiyama Hiroshi
Published: August 2008

In this paper, a new experimental method of full scale real time shaking table test of structural element is introduced. The main feature of this experimental method is characterized by the use of the inertial loading equipment. The inertial loading equipment consists of a loading frame, a counter weight and isolators. The loading frame supported by the isolators was set on the shaking table. Specimens used in this experimental method were partial frames taken out from full scale building structures. The test set-up was composed of a specimen, the inertial loading equipment and loading beam which transmits the horizontal force to the specimen from the inertial loading equipment. This test set-up, regarded as a single degree of freedom system, makes it easy to understand the dynamic behavior of the test set-up including a specimen. Furthermore, the natural period of the experimental system corresponds to the fundamental natural period of existing building structures. So, full scale and real time dynamic loading test of partial frame can be realized. This method was developed for the existing large scale shaking table and the effectiveness has been already verified through many experiments. Further development of the experimental method adjusted to the 3-D largest shaking table under construction at present is also described.
Alternative Control Design Approach to Shaking Facilities for Re-Creating Seismic Motion
Authors: Sato Eiji , Kakegawa Tomoyoshi , Suzuki Taku , Kajiwara Koichi , Tagawa Yasutaka , Takai Shigemitsu
Published: August 2008

The 3-D Full-Scale Earthquake Testing Facility (E-Defense) is now under construction in Miki City near Kobe. When completed, the facility will have a 750-ton shaking table measuring 20m by 15m, with a maximum load mass of 1200 tons. It will be able to create vibration in three dimensions with six degrees of freedom. However, the test model considered for this facility has a mass of 1200 tons compared to the shaking table mass of 750 tons, i.e., 1.6 times as heavy as the shaking table and much larger than ordinary test models. In addition, the vibration characteristics change considerably during the experiment due to the damage done to the test weight. Therefore, a better control design is urgently needed in order to overcome these problems. This research suggests a control method that will reproduce the earthquake wave accurately on the shaking table and will consider the robustness. Moreover, we will verify its efficiency by performing a control experiment using an existing two–dimensional, three-degree-of-freedom small shaking table, to which this control method is applied.
New Development of Control Method of Shaking Table With Bi-Linear Structures
Authors: Shimizu Nobuyuki , Shinohara Yuichirou , Sato Eiji
Published: August 2008

The Hanshin-Awaji earthquake disaster occurred in Kobe area of Japan in 1995. Considering the lessons learned from the disaster of this earthquake, Japanese government has decided to construct a three-dimensional Full Scale Earthquake Testing Facility. It is now being constructed under the supervision of the National Research Institute for Earth Science and Disaster Prevention (NIED). The purpose of this shaking table is to conduct fracturing tests rather than elastic vibration tests for full scale structures. In the tests, the classical operation and control procedure for shaking table such as the trial excitation cannot be effectively applied to this shaking table, because dynamic property of the test structure varies with the progress of fracturing. Therefore, the development of a new operation and control method for the shaking table is the urgent research subject. In this study, firstly, we studied dynamic interaction behaviors of the shaking table with a bi-linear test model. Secondly, to reduce the interaction from the motion of the shaking table, the Minimal Control Synthesis (MCS) algorithm was newly introduced into the conventional control (CC) system. This paper deals with the efficacy of the MCS algorithm through the simulations and experiments using the two dimensional small scale shaking table with a bi-linear model structure.
A Multi-Point Radio Displacement Measurement Method for Testing Quake-Proof Structure
Authors: Okamura Atsushi , Mikoshiba Tadashi , Yosizaki Wataru , Nagai Hideki , Mogi Atsushi , Sekiguchi Takashi , Kikuchi Hiroshi
Published: August 2008

In this paper, we propose a remote 3-D displacement measurement method using the radio wave for indoor shaking table facilities. It also shows the effectiveness of the proposed method by some radio experiments using a shaking table. The proposed measurement system consists of simple transmitters attached to each reference point and several receiving antennas at different places connected with a digital signal processing unit. The locations of the transmitters are simultaneously estimated by observing the phase differences between signals at receiving antennas. This prototype radio experimental system consists of 3 transmitters of frequency 2.45GHz, 4 receiving antennas and a microcomputer. We made the demonstration for the reconstructions of the 0.1Hz and 2Hz sinusoidal excitations at 3 reference points of the testing structure on the shaking table. The accuracy of estimated displacement was several centi-meters to several mili-meters.
Seismic Proving Test of Eroded Piping: Program and Preliminary Analysis of Eroded Piping Tests
Authors: Namita Y. , Suzuki K. , Abe H. , Ichihashi I. , Shiratori M. , Iwata K. , Kojima N. , Ishiwata M.
Published: August 2008

In 2000FY, a 3 year program of eroded piping tests was initiated with the following objectives: 1) to ascertain the seismic safety margins for eroded piping designed under the current seismic design code, 2) to clarify the elasto-plastic response and ultimate strength of eroded nuclear piping. It was intended to carry out a series of tests on eroded piping components and eroded piping systems. This paper is a report on the program of eroded piping tests.
Seismic Proving Test of Ultimate Piping Strength: Test Results on Piping Component and Simplified Piping System
Authors: Suzuki Kenichi , Namita Y. , Abe H. , Ichihashi I. , Suzuki Kohei , Ishiwata M. , Fujiwaka T. , Tai K.
Published: August 2008

In 1998FY, the 6 year program of piping tests was initiated with the following objectives: i) to clarify the elasto-plastic response and ultimate strength of nuclear piping, ii) to ascertain the seismic safety margin of the current seismic design code for piping, and iii) to assess new allowable stress rules. In order to resolve extensive technical issues before proceeding on to the seismic proving test of a large-scale piping system, a series of preliminary tests of materials, piping components and simplified piping systems is intended. In this paper, the current status of the piping component tests and the simplified piping system tests is reported with focus on fatigue damage evaluation under large seismic loading.
Seismic Proving Test of Heavy Component With Energy Absorbing Support: Proving Test Results
Authors: Iwatsubo T. , Konno M. , Abe H. , Kuroda K. , Tai K. , Sumiya H.
Published: August 2008

The Seismic Proving Test of Heavy Component with Energy Absorbing Support has been conducted to prove the reliability of advanced seismic technology, supporting heavy component such as PWR Steam Generator with large capacity energy absorbing supports. This paper introduces the result of the proving test, using 1/2.5 scale model of PWR Steam Generator supported by Lead Extrusion Damper (LED), conducted on 2000–2001. This project has been conducted by the Nuclear Power Engineering Corporation (NUPEC) since 1995, using a large-scale, high-performance shaking table at Tadotsu Engineering Laboratory under the sponsorship of the Ministry of Economy Trade and Industry. Up to 2.9 S2 (extreme design earthquake), LED showed stable energy absorbing performance and Steam Generator- primary piping system indicate no meaningful damage.
A New Design Method for Piping Components Against Leakage and Damage Subjected to High Level Earthquake Load
Authors: Ando Fumio , Sawa Toshiyuki , Ikeda Masatoshi
Published: August 2008

A design method of piping components for Level 2 earthquake (the possible strongest earthquake with extremely low probability of occurrence) such as bolted flanged joints, expansion joints, and equipment nozzles is described. This design method is provided taking into account their failure modes and degree of safety. The failure modes for each piping component is classified according to the past damage experience due to earthquake, and each criterion is provided against the failure mode. The typical failure modes are gas leakage, fatigue failure, cumulative plastic deformation during and after earthquake for bolted flanged joints, expansion joints and equipment nozzles in piping components, respectively. Specifically, the simplified method of bolted flanged joints is proposed as the convenient design method for chemical plants and petroleum refineries, etc. (here in after calls as plant) The method is derived using gasket factor, gasket dimensions and clamping forces due to bolts for external piping load. This practical method is investigated and verified due to the experimental results on the welding neck type flanges subjected to static bending moment, in which the bolted flanged joints of NPS 4″ and 8″ in size, 3 types of gaskets are used. In addition, the dynamic inertia force effect is also studied by the shaking table tests using cantilever model of bolted flanged joints at fixed side with changing the bolt clamping forces and gasket types.
An Advanced Computational Method for Nonlinear Behavior of Piping Systems Subject to Earthquake Load
Authors: Mukaimachi Norihiko , Ando Fumio , Ikeda Masatoshi
Published: August 2008

With regard to piping systems of industrial facilities, sometimes they are subject to large deformation with high local plasticity. This results mainly from the detrimental ground movement due to possible liquefaction near seaside when a strong earthquake occurs. Especially the high local plasticity concentrates on elbows (bends) in piping systems. In this paper, the elbow behaviors of in-plane (closing: deflection to decrease elbow radius of curvature and opening: deflection to increase its radius of curvature) and out-of-plane bending are analyzed in a large plastic range using Nonlinear Finite Element Method (FEM) with the shell elements of material and geometrical nonlinear characteristics. The flexibility factor of elbows depends on flexibility characteristics, angular distortion and yield stress of material. Thus, in order to estimate the behaviors of piping systems with large plasticity at elbow by a simplified method, the modified flexibility factor method is introduced from results of FEM. Calculation results obtained using the simplified method are compared with experimental results, and this method gives an index to assess behaviors of piping systems subject to extremely large movement of supports. It is also possible to estimate local plasticity at elbows in piping systems by this conventional analysis.
Dynamic Buckling Behavior of an Elastic Beam Subjected to Horizontal and Vertical Excitations Simultaneously
Authors: Fujita Katsuhisa , Nosaka Taisuke
Published: August 2008

The purpose of our study is on the dynamic instability, that is dynamic buckling, of structures such as elevated expressways, towers and high-storied building subjected to a horizontal and a vertical excitations simultaneously. The coupled motion of equation with a horizontal and a vertical excitations simultaneously for these structures is derived in this paper, and this modeling is shown to become a Mathieu type’s parametric excitatoin. The numerical simulation analysis is carried out for an elastic beam model with an attached mass on its tip instead of a shell model as a first step of our study. Comparing with the classical seismic analysis method, this proposed dynamic stability analysis method shows the larger deformation in horizontal direction due to the parametric excitation of a vertical seismic wave.
Vertical Response of Multi-Story Structures at the Instance of Maximum Horizontal Response
Authors: Taniguchi Tomoyo
Published: August 2008

A vertical response of a multiple degree of freedom system vibrating in axial modes at the instance of its maximum horizontal response vibrating in shear modes is analyzed by superposition of normal modes. The coincident vertical response acceleration at the instance of the maximum horizontal response acceleration between two independent single degree of freedom systems indicated probabilistic properties. It is of interest to extend concepts of the response coincidence in the response analysis of multi-story structures. Nevertheless, the distribution of the coincident vertical response along the building height may be the most important in connection with the seismic design. Its probable distribution and an approximate upper bound are investigated to determine an analysis constant. The analysis constant enables the computation of the coincident vertical response of multi-story structures at the instance of the maximum horizontal response by the modal analysis. The results of the proposed method and the direct numerical integration of governing equations of motion are compared, and conclusions are drawn about the use of the modal analysis to the coincident vertical response of multi-story structures.
Analytical Exploration of the Time History Analysis of Shock Response
Authors: Chang Shuenn-Yih
Published: August 2008

It was experienced that a very small time step may be needed in the solution of the shock response from an impulse. In fact, this time step might be much smaller than the time step to have accurate representation of the impulse and negligible period distortion. It is theoretically verified that this difficulty is arising from the discontinuity in external force at the end of an impulse. In addition, a technique to estimate the relative amplitude error caused by this discontinuity is also developed. In fact, the accuracy of the shock response from a linear impulse is thoroughly explored both in amplitude and in period. Analytical results show that the accuracy is almost entirely dominated by the relative amplitude error tbr the impulse with significant discontinuity in external force at the end of the loading duration. Meanwhile, for the impulse without any discontinuity numerical accuracy is controlled by the relative period error in the solution of the shock response. Finally, guidelines to have accurate shock response from an impulse are proposed.