scholarly journals Review of the regulatory periodic inspection system from the viewpoint of defense-in-depth in nuclear safety

2018 ◽  
Vol 50 (7) ◽  
pp. 997-1005
Author(s):  
Jihan Lim ◽  
Hyungjin Kim ◽  
Younwon Park
Keyword(s):  
Nuclear Safety ◽  
Inspection System ◽  
Periodic Inspection ◽  
Defense In Depth

THE STUDY OF DEGRADATION CONDITION OF HIGH-RISE BUILDING EXTERIOR WALL

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Chu-Tsen Liao ◽  
Kuang-Jou Chen ◽  
Jen-Chun Hsiao ◽  
Po-Jui Wu ◽  
You-Zhen Fu
Keyword(s):  
Reference Material ◽  
Wall Tile ◽  
City Government ◽  
Inspection System ◽  
Exterior Wall ◽  
External Wall ◽  
Contract Research ◽  
High Rise ◽  
Periodic Inspection ◽  
Seismic Forces

In recent years in Taiwan, some pedestrians were injured by falling external wall tiles. Exterior wall tile fell down for the temperature or other effects of seismic forces, becoming a potential public safety crisis. Office of Building Administration of Taoyuan City Government started inspecting high-rise buildings, which were over eleven stories and constructed before 1995 in Taoyuan city from 2015 to 2016. This study is a contract research. We inspected 298 high-rise buildings’ external wall tiles in Taoyuan City for city government. In this study, we classified the risk of buildings from Level A to E. D and E, which were regarded as the dangerous buildings and in need of repair immediately. D and E accounted for 41.6% percent of total buildings. We also concluded the data in the viewpoints of building age, story, exterior material, direction, and district. The authors hope the conclusion of this study could be submitted as reference material of inspection system, as well as give a significant suggestion to the periodic inspection approach in the future.

scholarly journals A review on the defense-in-depth concept and the flex strategies in different countries after Fukushima accident

2021 ◽  
pp. 13-13
Author(s):  
Hong Xu ◽  
Baorui Zhang
Keyword(s):  
Recent Decade ◽  
Nuclear Safety ◽  
Nuclear Accident ◽  
Fukushima Nuclear Accident ◽  
Research Progress ◽  
Fukushima Accident ◽  
The Past ◽  
Defense In Depth ◽  
Future Work ◽  
Support Guidelines

In order to enhance the defense in depth for nuclear safety after the Fukushima nuclear accident, U.S. Nuclear Energy Institute put forward the concept of Diverse and Flexible Coping Strategies and the corresponding FLEX support guidelines for the special scenarios of Extended Loss of Alternating current Power and Loss of Ultimate Heat Sink caused by Beyond-Design-Basis External Event. Subsequently, the idea of the FLEX strategy was widely accepted and spread widely. The introduction of the concept of FLEX strategy into the defense in depth was the biggest improvement for nuclear safety in the recent decade. This paper has reviewed the concept of traditional defense in depth and its weakness that led to the Fukushima nuclear accident, which led to the development motivation for the FLEX strategy. The research progress of the FLEX strategy in different countries in the past ten years has been reviewed. Based on the literature, and the above-mentioned review, some recommended future work has been given.

COG Risk-Informed In-Service Inspection (RI-ISI) Project

2012 ◽  
Author(s):  
Patrick J. O’Regan ◽  
Mehdi Rezaie-Manesh ◽  
Scott T. Chesworth
Keyword(s):  
Operating Experience ◽  
Nuclear Safety ◽  
Degradation Mechanisms ◽  
Acceptance Criteria ◽  
Risk Levels ◽  
Periodic Inspection ◽  
Starting Point ◽  
Best Fit ◽  
Service Inspection

In 2009, the Canadian Nuclear Safety Commission (CNSC) prepared “Guidelines for Risk-Informed In-service Inspection for Piping,” which provided guidance and acceptance criteria for licensees to develop an RI-ISI program as an alternate to the current CSA N285.4 and augmented programs for piping inspection. A project was initiated by the CANDU Owners Group (COG) to develop a best-fit RI-ISI methodology for the CANDU design and evaluate plant risk levels between current and RI-ISI inspection programs. The traditional EPRI RI-ISI methodology was selected as a starting point, and four plant systems were evaluated. Both failure potential and consequence of failure were used to establish the risk significance for all in-scope piping components. Once the risk associated with each component was established, elements were selected for inspection based upon the sampling percentages of the EPRI RI-ISI methodology, and as a final check a comparison was made between plant risk under the current CSA N285.4 (and augmented) inspection program and under RI-ISI. The project was successfully concluded in 2011, and results confirmed that the EPRI RI-ISI methodology can be adapted to the CANDU design and the degradation mechanisms evaluated under RI-ISI are consistent with CANDU operating experience. The original CSA N285.4 basis for the CANDU Periodic Inspection Program (PIP) was validated, and potential improvements to the station inspection programs were identified.

Development of Inspection System for Crack in R.C. Tunnel Lining by Using Knowledge-Based System (KBS)

2012 ◽  
Vol 622-623 ◽  
pp. 1415-1420
Author(s):  
Yousif A. Mansoor ◽  
Zhi Qiang Zhang
Keyword(s):  
Expert System ◽  
Knowledge Base ◽  
Visual Inspection ◽  
Tunnel Lining ◽  
Inspection System ◽  
Knowledge Based Systems ◽  
System Environment ◽  
Periodic Inspection ◽  
Knowledge Based ◽  
Satisfactory Answer

Over the last several years, many concrete tunnels have been constructed for roads, highways, and railways. For safety in concrete tunnel, periodic inspection has been conducted using many testing technologies and techniques. However, these technologies cannot replace visual inspection because of their slow and complicated procedures. For this reason, the Knowledge-Based Systems (KBS) are used to diagnose R.C tunnel lining crack damage (DICRCTL). In this paper, we attempt to propose an alternative to the human expert, to give technical decisions in diagnosing crack damages in second segment of R.C. tunnel lining. To overcome this requirement, an expert system is developed to achieve the research aim. This proposed system was constructed on a knowledge base that incorporates with the gathered information in the form of rules which is suitable to implement in an expert system environment to diagnostic advisory nature. The proposed application results show an easy, fast and satisfactory answer to engineering needs.

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