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The United States Nuclear Regulatory Commission issued requests for licensees to re-evaluate the seismic hazards at their sites after the accident at the Fukushima Daiichi Nuclear Power Plant in Japan on March 11 in 2011 and to identify and address any site-specific vulnerabilities associated with seismic hazards. The primary guidance for performing those evaluations is provided in the Electric Power Research Institute EPRI-1025287 report, which also provides guidance for evaluating spent fuel pool (SFP) integrity. In addition, the EPRI-3002009564 report also provides evaluation approaches regarding the effects of seismic ground motions on SFPs that supplement the guidance provided in EPRI-1025287. SFP integrity has become increasingly important for active and decommissioned nuclear power plants. According to EPRI-1025287, the SFP integrity evaluation emphasizes failure modes of the SFP that could result in “rapid drain-down.” The definition of “rapid drain-down” is a failure that could lead to the uncovering of irradiated fuel stored in the SFP within 72[Formula: see text]h of an earthquake. Possible failures can be classified into two categories: failures relevant to the SFP structure and failures relevant to non-structural elements. This paper aims to study the approaches of implementing seismic evaluation of an SFP structure. EPRI-3002009564 provides separate seismic evaluation approaches for plants with a ground motion response spectrum (GMRS) peak [Formula: see text][Formula: see text]g and for plants with a GMRS peak [Formula: see text][Formula: see text]g. Structural dynamic analysis is also a common approach for implementing seismic evaluation if a detailed finite element model is available. In this paper, a sample SFP structure was evaluated using the two approaches, structural dynamic analysis and structural analysis criteria. The results indicate that shear failure controlled the failure mode of the SFP structure for both approaches. This shows that the two approaches drew the same conclusion regarding the failure mode. Furthermore, a smaller seismic margin was obtained using the structural analysis criteria, which means this evaluative approach is more conservative.

An earthquake with an epicenter offshore of Hualien City in eastern Taiwan occurred at midnight on February 6, 2018. The Richter magnitude (ML) of the earthquake was 6.26 and the seismic intensity ranged up to level VII, the strongest seismic intensity level regulated in Taiwan. Almost all the major damage resulting from this seismic event was occurred near both sides of the Milun Fault, where records from nearby strong motion stations displayed the characteristics of near-fault ground motions. The main seismic damage was the collapse of four buildings with soft bottom stories, one of which resulted in fourteen of the seventeen total fatalities. Comparing the acceleration response spectra with the design response spectra sheds light on the effects of near-fault ground motions on the collapsed buildings. Based on the eventual forms of collapsed buildings, building collapses that have generally led to major casualties in past seismic events around the world can be classified into sit-down, knee-down and lie-down types. In addition to the four collapsed buildings, seismic reconnaissance on other buildings, bridges, ports, and non-structural components have also been conducted. This study explores the issues and challenges arising from the reconnaissance results and thereby enhances learning from the seismic event.

For numerical analysis or shaking table tests of in-cabinet equipment, in-cabinet response spectrum (ICRS) is adopted as required seismic demand. Several kinds of simplified concepts are commonly u...

The long period velocity pulse is recognized as one of the characteristics of near-fault ground motions, and hence the response of vibration modes with lower frequencies will be amplified owing to the resonant effect. In general, the sloshing frequency of storage liquid is low and the period is similar to the pulse period of near-fault ground motions. Compared to the far-field ground motions, the induced sloshing height will be amplified by the near-fault ground motions. Therefore, it is worth paying attention to the resonant effect of near-fault ground motions on the sloshing mode of storage liquid in tanks. An experiment was implemented to study the resonant response of sloshing mode. The purpose of this experiment is to estimate the slosh height and the associated total volume of water splashing out of the tank under near-fault ground motions, and also to determine the relationship between the resonant response and the input velocity pulse. This paper aims to describe the test plan in detail, and it consists of (1) design of the scaled storage tank and water depth, (2) selection and processing of the input motions including the original near-fault ground motions, extracted velocity pulse or extracted bandpass signals for resonance analysis, and also impulse motion for free vibration, (3) setup of measure instrument, and (4) the experimental procedures as well. Preliminary analysis results are compared with the code-specified values that is determined by the industrial standards and guidelines for general seismic conditions. It is noted that the proposed prediction equation can be applied to the seismic design and evaluation of spent fuel pool in nuclear power plants.

Based on recent earthquakes experiences in Taiwan, losses do not necessarily result from damages of building structures but non-structural components. For instance, the leakage of the fire protection sprinkler systems in hospitals during small earthquakes could results in shortage of medical function and fire protection, and malfunction and repairs of medical equipment. The break of sprinkler systems caused by strong earthquakes could even harm the life safety. Taking a medium-scale hospital as an example, this research aims to conduct a simplified seismic evaluation method to improve seismic performance of the fire protection sprinkler system in critical buildings. The content of this research is summarized below: 1. Numerical analysis of the sample sprinkler piping system: a detailed numerical model of the fire protection sprinkler system in the sample hospital was established with SAP2000 v.20 software. Proper parameters to simulate the threaded joint of piping and the gap between adjacent partition walls or ceiling systems were proposed and verified by the results of component tests and shaking table tests. Ambient vibration tests in the sample hospital were conducted with velocimeters to clarify the structural characteristics of the building structure and the sprinkler piping system. 2. Fragility analysis of sprinkler piping systems: seismic fragility curves the fire protection sprinkler system in the sample hospital were conducted according to a mount of detailed analysis results and verified by the real damage state under Jiaxian earthquake. The effects of engineering demand parameters and categories of ground motion on fragility results are discussed for three types of failure modes. 3. Simplified seismic evaluation method for sprinkler piping systems: according to the results of shaking table tests and detailed analysis, a reliable simplified evaluation method was established to predict seismic behavior of typical sprinkler piping systems in hospitals by the information obtained from in-situ survey. The conservative level and accuracy of simplified evaluation results were verified by comparing the results of fragility analysis of numerical model and simplified evaluation.

A prototype diesel generator equipped with a vibration isolation system consisting of restrained isolators (denoted as I/system) is quasi-statically and dynamically tested. Sequentially, the seismic simulation tests are conducted to further investigate the effectiveness of additional snubbers incorporated into the vibration isolation system (denoted as I/R system). Comparing the test results to the static design demands specified in ASCE 7-10, the recommended component amplification factor could represent the horizontal acceleration amplification phenomenon of the generator equipped with I/R system; however, the seismic force demands for static design of I/R system might not be appropriate and conservative enough.

From the experience gained from recent earthquakes, it has been recognized that the earthquake resisting capacity of so-called responsibility hospitals for acute services in Taiwan should be upgraded. These hospitals, which have been tasked with the provision of emergency services after major earthquakes, should remain functional with regard to their structures, medical facilities, electricity and water supply, and information services. In order to facilitate the issuing of governmental policies and practical engineering services regarding the seismic upgrading of hospitals, the objective of this paper is to determine the seismic rehabilitation objectives of essential medical equipment and non-structural components in responsibility hospitals, and further, to propose seismic evaluation and strengthening guidelines. Owing to the onerous work required to improve the seismic performance of various nonstructural components, a simplified programme is established using Microsoft Excel software to execute a preliminary seismic evaluation and retrofit design for individual pieces of medical equipment. Users are asked to fill in blanks with hospital information and the parameters of selected equipment and then the programme identifies the performance objective of each piece of equipment. It also determines whether the equipment should be retrofitted or not. In addition, preliminary designs of post-installation anchor bolts for seismic retrofitting against specified seismic demands can be checked automatically by the programme.

Based on the issue of life safety and immediate needs of emergency medical services provided by hospitals after strong earthquakes, this paper aims to introduce a research programme on assessment and improvement strategies for a typical configuration of sprinkler piping systems in hospitals. The study involved component tests and subsystem tests. Cyclic loading tests were conducted to investigate the inelastic behaviour of components including concrete anchorages, screwed fittings of small-bore pipes and couplings. Parts of a horizontal piping system of a seismic damaged sprinkler piping system were tested using shaking table tests. Furthermore, horizontal piping subsystems with seismic resistant devices such as braces, flexible pipes and couplings were also tested. The test results showed that the main cause of damage was the poor capacity of a screwed fitting of the small-bore tee branch. The optimum improvement strategy to achieve a higher nonstructural performance level for the horizontal piping subsystem is to strengthen the main pipe with braces and decrease moment demands on the tee branch by the use of flexible pipes. The hysteresis loops and failure modes of components were further discussed and will be used to conduct numerical analysis of sprinkler piping systems in future studies.

This study aims to establish ordinary seismic demands imposed on safety-related electrical instruments mounted in electrical cabinets (referred to as in-cabinet equipment) in nuclear power plants and to understand the basic characteristics of the dynamic responses for electrical cabinets. An existing cabinet used in the Maanshan nuclear power plant was adopted as a specimen for a shaking table test. The vibration responses and spectral amplification factors of the tested cabinet under different shaking intensity levels, as well as the variation of total mass and anchorage locations of additional weights attached to the cabinet, are studied and summarized in this study. The results of this preliminary study can contribute to developing a complete test plan for motor control centers in the Lungmen nuclear power plant in future studies.

This study, with the shake table experiments in the National Earthquake Engineering Research Center, investigated the seismic behavior of automation stocker system. The automation stocker system provided a fast and effective method for stocking products in the high-tech facilities. Firstly, the original machine tests for testing common stocker system were to investigate the seismic capacity and failing modes. Secondly, the team completed 2 kinds of reinforcement tests to investigate the seismic behavior: 1) the installation of bracing to improve overall stiffness; 2) the installation of the viscous dampers to improve the overall damping ratio. In comparing the results and performance of the three experiments, we learned from the results of the top-layer acceleration: the installation of bracing had the largest acceleration value, the original machine the second acceleration value and the damper the lowest acceleration value; the best effect was the installation of the damper. The result of the comparison of the top floor displacement meter showed that the highest data was the original machine; the second data was with the damper, the lowest data was the installation of the bracing. Based on the preliminary assessment on the best seismic retrofit ways of the storage system, we further examined the feasibility and applicability of automatic storage seismic retrofit in the high-tech factory.

Although the overproduction of immunoglobulins by short-lived plasma cells accompanying an immune response links with their apoptosis, how long-lived plasma cells adapt to ensure their longevity in this context is obscure. Here, we show that apoptosis signal–regulating kinase 1 (ASK1) contributes to apoptosis of plasma cells because ASK1 activity was induced during differentiation of short-lived plasma cells, and, when produced by ASK1-deficient mice, these cells survived better than those of control mice. Moreover, antigen-specific long-lived plasma cells generated by immunization accumulated in ASK1-deficient mice, suggesting ASK1 also plays a negative role in survival of long-lived plasma cells. In malignant plasma cells, ASK1 transcription was directly suppressed by B lymphocyte–induced maturation protein-1 (Blimp-1). The expression of ASK1 and Blimp-1 showed an inverse correlation between normal human mature B cells and bone marrow plasma cells from patients with multiple myeloma (MM). Suppression of ASK1 is crucial for cell survival because its enforced expression in MM cells caused apoptosis in vitro and lowered MM load in a xenograft animal model; furthermore, alteration of ASK1 activity affected MM cell survival. Our findings indicate a novel mechanism underlying the regulation of survival in normal and malignant plasma cells by ASK1.

The performance of gap springs in a guideway sliding isolator (GSI) system developed to protect precision machinery against seismic motion has been studied. A spring is initially distanced from the system by a gap, causing the isolation system to exhibit nonlinear performance once the gap is closed, reducing the chance of resonance. A full-scale shaking table test of a 22-ton specimen and a numerical model simulation in SAP2000 have been performed. The study shows that springs possessing the appropriate gaps are more effective in controlling relative displacements than is a pure friction system. The optimal gap for a system subjected to far-field earthquakes was found to be 5mm. In addition, supplemental viscous damping of less than 15% of the critical damping had no significant effect on the GSI system far-field seismic response, but it did reduce the relative displacements of the system for near-fault seismic excitations.

According to the seismic risk assessment results presented in the Final Safety Analysis Report (FSAR) for a nuclear power plant in Taiwan, the failure of Residual Heat Removal (RHR) piping system occurs in both of the two accident sequences with the highest contributions for core damage. The seismic performance of RHR piping system depends on the capacity of its components, such as supports, flanged joints and reducers. For the need of seismic response-history analysis of RHR piping systems, we developed detailed numerical models of flanged joint and reducer using finite element analysis software (ABAQUS and SAP2000). The proposed finite element models were verified by the experimental results. The pure bending tests with four-point cyclic loading were conducted for sample flanged joint and reducer to investigate their mechanical behaviors. The displacement and rotation responses identified from the tests are in good agreement with the results of numerical analysis. A preliminary simplified model of flanged joints was also proposed in this study to improve the efficiency of numerical analysis for RHR piping system.Copyright © 2014 by ASME

Based on the immediate needs of emergency medical services provided by hospitals after strong earthquakes, this paper is to introduce a research program on assessment and improvement strategies for typical configuration of sprinkler piping systems in hospitals. The study involved component tests and subsystem tests. Cyclic loading tests were conducted to investigate inelastic behavior of components including concrete anchorage, screwed fittings of small bore piping and mechanical couplings. Parts of horizontal piping systems of the aforementioned seismic damaged sprinkler piping system were tested using shaking table tests. Furthermore, the horizontal piping subsystems with seismic resistant devices such as braces, flexible pipes and mechanical couplings were tested. The test results show that the main cause of the damaged case is the poor shear capacity of the screwed fitting of the small-bore tee branch. The optimum improvement strategy to achieve higher nonstructural performance level for the horizontal piping subsystem is to strengthen the main pipe with braces and to decrease shear demands on the tee branch by flexible pipes. The hysteresis loops and failure modes of components were further discussed and will be used to conduct numerical analysis of sprinkler piping systems in future studies.

Based on the experiences learned from recent earthquakes, it is recognized that the earthquake resisting capacity of the responsibility hospitals with acute services should be upgraded. These hospitals assigned to provide emergency services after major earthquakes should remain functional for their engineering structures, medical facilities, electricity and water supply, and information services. However, in Taiwan, the medical equipment and supporting facilities have not been carefully inspected and seismically upgraded yet. Therefore, in order to facilitate the governmental political issue and practical engineering services regarding the seismic upgrading of hospitals, the objective of this paper is to determine the seismic rehabilitation objectives of essential medical equipment and nonstructural components in responsibility hospitals, and further, to propose the seismic evaluation and strengthening guidelines. In addition, due to the lack of research on nonstructural components, several experimental studies on seismic behavior of critical equipment and components, such as the fire protection sprinkler systems, post-installed anchorage attachment, and flexible mechanical coupling joints for piping systems were implemented to support the proposed evaluation and strengthening guidelines.

In order to ensure the operation of nuclear power plants (NPPs) during and after earthquakes, an overall reevaluation of the seismic performance in NPPs is proceeding in Taiwan. The issue of in-cabinet relays within cabinets is focused due to their importance for safety function and unstable seismic capability. To explore the rationality of general adopted seismic evaluation methods for in-cabinet relays, in-cabinet response spectrum (ICRS), the seismic demand on in-cabinet equipment, was studied through shaking table tests of the typical motor-control-center (MCC) type cabinets in NPPs. A simplified numerical method is proposed based on the observation of shaking table test results. The global modes were simulated by a lumped-mass model, and local modes were simulated by a detailed finite element model of the plate at which in-cabinet equipment is anchored. The ICRS and in-cabinet amplification factors (AF) estimated by the proposed method were discussed by the comparison with the shaking table test results, the frequency domain analysis (FDA) based on EPRI NP-7146-SL Report, and the complete finite element model of the cabinet. From above observation, the proposed model can predict global and local cabinet behaviors better in contrast to the FDA results, but cannot fit the local cabinet behavior very well. Future research effort will be to improve the proposed method to overcome the underestimate of the local behavior and other unexpected higher frequency response.

Plasma cell differentiation is orchestrated by the transcriptional repressor B lymphocyte-induced maturation protein-1 (Blimp-1), which silences the gene expression program of mature B cells. The molecular mechanism underlying Blimp-1 suppression of mature B-cell gene expression is not fully understood. Here we report that a proline-rich domain in Blimp-1 directly interacts with LSD1, a histone lysine demethylase. Both LSD1 knockdown and expression of Blimp-1 lacking the proline-rich domain derepressed the activities of Blimp-1-dependent luciferase reporters. Disruption of the Blimp-1 interaction with LSD1 or reduced LSD1 expression attenuated antibody production, demonstrating the biological significance of this interaction. Finally, using chromatin immunoprecipitation, we showed that Blimp-1 binding to its target sites is accompanied by LSD1 binding to those same sites and that LSD1 binding correlates with histone modifications of accessible chromatin. These findings provide further insights into the molecular mechanism of the silencing of mature B-cell genes by Blimp-1 in plasma cell differentiation.