The Implementation of the Gradual Movement of Sliding Blocks to a New Method for Evaluating the Seismic Stability of Slopes Reinforced by Geotextile

2018 ◽  
Vol 12 (04) ◽  
pp. 1841010
Author(s):  
Tadashi Kawai ◽  
Makoto Ishimaru
Keyword(s):  
Seismic Performance ◽  
Nuclear Power ◽  
Power Plants ◽  
Slope Failure ◽  
Failure Process ◽  
Tohoku Earthquake ◽  
Seismic Stability ◽  
Centrifuge Tests ◽  
Stability Of Slopes ◽  
Design Basis

Evaluating the seismic stability of a rock slope typically involves searching for the minimum value of calculated safety factors (SF) for each supposed sliding block. Because only the transient equilibrium is evaluated, the likelihood of any slope failure can be deemed negligible if all the calculated SFs are greater than unity. However, even if some of the calculated SF are less than unity, it cannot be assumed that the slope will collapse. Recently, in the wake of extremely large earthquakes in Japan, the design earthquake standards for nuclear power plants (NPP) have been extended. After the experience of the 2011 off the Pacific coast of Tohoku Earthquake, the designer is expected to consider beyond design basis earthquakes to determine whether more can reasonably be done to reduce the potential for damage, especially where major consequences may ensue [IAEA (2011). IAEA international fact finding expert mission of the Fukushima dai-ichi NPP accident following the Great East Japan Earthquake and Tsunami, Mission report, IAEA]. With this in mind, the method employed to evaluate the seismic performance of the slope surrounding an NPP needs to be capable of doing more than determining the likelihood of failure: it must also consider the process toward failure in the event of an earthquake beyond the design basis. In this paper, a new evaluation flow which considers the failure process is proposed to evaluate the seismic performance of slopes surrounding an NPP. This is followed by confirming the validity of the concepts in the proposed flow chart by re-evaluating centrifuge tests in past literature and the numerical simulations designed for those tests.

scholarly journals Seismic Vulnerability Assessment of Site-Vicinity Infrastructure for Supporting the Accident Management of a Nuclear Power Plant

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
T. J. Katona ◽  
A. Vilimi
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Disaster Management ◽  
Nuclear Power ◽  
Power Plants ◽  
Public Utility ◽  
Qualitative Assessment ◽  
Design Basis ◽  
Accident Management ◽  
Plant Site

Nuclear power plants shall be designed to resist the effects of large earthquakes. The design basis earthquake affects large area around the plant site and can cause serious consequences that will affect the logistical support of the emergency actions at the plant, influence the psychological condition of the plant personnel, and determine the workload of the country’s disaster management personnel. In this paper the main qualitative findings of a study are presented that have been performed for the case of a hypothetical 10−4/a probability design basis earthquake for the Paks Nuclear Power Plant, Hungary. The study covers the qualitative assessment of the postearthquake conditions at the settlements around the plant site including quantitative evaluation of the condition of dwellings. The main goal of the recent phase of the study was to identify public utility vulnerabilities that define the outside support conditions of the nuclear power plant accident management. The results of the study can be used for the planning of logistical support of the plant accident management staff. The study also contributes to better understanding of the working conditions of the disaster management services in the region around the nuclear power plant.

scholarly journals An Enhanced Preventive Maintenance Optimization Model Based on a Three-Stage Failure Process

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Ruifeng Yang ◽  
Jianshe Kang ◽  
Zhenya Quan
Keyword(s):  
Optimization Model ◽  
Preventive Maintenance ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Failure Process ◽  
Maintenance Optimization ◽  
Maintenance Policy ◽  
Model Based ◽  
Inspection Interval

Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models.

scholarly journals Effective Diaphragm Area Test Program for Air Operated Valve Actuators

2017 ◽  
Author(s):  
Zachary Leutwyler ◽  
Manmohan Kalsi ◽  
Lisa Thidavanh ◽  
Laurie Luckhardt ◽  
Thomas Cunningham
Keyword(s):  
Measurement Uncertainty ◽  
Nuclear Power ◽  
Power Plants ◽  
Reliable Data ◽  
Product Line ◽  
Test Program ◽  
Test Matrix ◽  
Design Basis ◽  
Manufacturing Tolerances ◽  
Measurement Uncertainties

GE contracted Kalsi Engineering, Inc. (KEI) to perform actuator testing to determine the effective diaphragm area for the Model 37/38 actuator line and to develop a bounding effective diaphragm area tolerance to account for measurement uncertainties and manufacturing tolerances. The GE sponsored test matrix includes Model 37/38 Sizes 9, 11, 13, 15, 18, and 24 actuators. The test matrix was primary defined to provide EDA data for actuators used in US nuclear power plants. The test matrix was primarily designed to facilitate the evaluation of the effects of stroke position, pressure, diaphragm materials, and measurement uncertainty. The test matrix also included with and without spring test configurations, two spring options for the same actuator size and model, and two diaphragm materials: Nitrile Elastomer and Silicone. The test program provides reliable data for AOV design basis evaluations as required by the NRC RIS 2000-03. This paper presents the results for the Masoneilan Model 38 Size 11 diaphragm actuator, which show that EDA is strongly position dependent and weakly pressure-dependent. As part of the project, a method for determining the required EDA tolerance to account for manufacturing variations was developed, which allows EDA determined by testing to be used across the product line. Paper published with permission.

Motor-Operated Valve Importance Categorization Study Using Level 1 Internal PSA

2002 ◽  
Author(s):  
Yong Suk Lee ◽  
Chang Hyun Chung ◽  
Key Yong Sung
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Testing Program ◽  
Design Basis ◽  
Periodic Testing ◽  
Internal Event ◽  
Level 1

Recently GL 89-10 static and dynamic Motor-Operated Valve (MOV) tests are being performed in Korean nuclear power plants to ensure MOV operability in design basis condition. And GL 96-05 MOV periodic verification testing will be followed after GL 89-10 testing. MOV risk importance categorization will be incorporated in Korean MOV periodic testing program for effective MOV test. In this study, MOVs were preliminarily categorized based on risk importance measures FV and RAW using level 1 internal event PSA. Configuration effect and importance uncertainty effect to risk importance of MOVs were also investigated.

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