scholarly journals B Plant low level waste system integrity assessment plan

1994 ◽  
Author(s):  
E.J. Walter
Keyword(s):  
Integrity Assessment ◽  
Low Level ◽  
System Integrity

In-Service Dent Management From an Operator’s Perspective

2004 ◽  
Author(s):  
Keith Adams ◽  
Joe Zhou
Keyword(s):  
Cyclic Stress ◽  
Management Program ◽  
Low Resolution ◽  
Element Analysis ◽  
Stress Concentrators ◽  
Integrity Assessment ◽  
The Past ◽  
System Integrity ◽  
Integrity Management

Pipeline dents are common occurrences that have a potential integrity threat to the system. Dents are typically found through in-line inspections, and historically, low-resolution in-line inspection geometry tools were used to find the locations of dents. These tools gave little information about shape, orientation or other dent features. Newer ‘high-resolution’ tools give a much clearer picture of the dent shape, location, orientation and location of welds. This information has been previously unavailable and has enabled dent integrity assessment with much greater accuracy and confidence. However this still leaves the question of how to best address the information from older, low-resolution inspection tools. In the past, CSA Z662 required that all dents with a deflection greater than 6% or that contained stress concentrators, including welds, had to be repaired. In the newly published 2003 edition of CSA Z662, dents can be assessed by an engineering assessment to determine their acceptability. Historical evidence has shown that dents less than 6% can also be subject to failure under certain conditions, and is indicated in the notes of CSA Z662-03 10.8.2.4.2. Dents that contain stress concentrators, including corrosion, welds and cracks must be given special consideration, however often little information is available for the dent from solely a geometry tool. TransCanada PipeLines Limited has been involved in the development of a dent assessment methodology for several years. Based on the 2003 revisions to CSA Z662, TransCanada has started to implement a dent integrity management program. This paper discusses the approach taken by TransCanada: to create a database of dent features, classification of dents, finite element analysis (FEA) to determine cyclic stress spectra, fatigue analysis, validation through dig programs, and the management of these features from a system integrity standpoint.

A dynamic sampling scheme for GPS integrity assessment

2006 ◽  
Vol 110 (1105) ◽  
pp. 129-143 ◽  
Author(s):  
S. Feng ◽  
W. Ochieng ◽  
D. Walsh ◽  
R. Ioannides
Keyword(s):  
Performance Assessment ◽  
Single Point ◽  
Air Traffic ◽  
Navigation Systems ◽  
Integrity Assessment ◽  
Temporal Sampling ◽  
System Integrity ◽  
Reliable Assessment ◽  
Receiver Autonomous Integrity Monitoring ◽  
Dynamic Sampling

Abstract The Global Positioning System (GPS) is already being used for certain aviation applications and some safety critical air traffic services will be based on GPS. These air traffic services must achieve allowable levels of safety before they can be accepted. For this to occur, GPS based navigation systems must achieve a defined level of performance specified in terms of accuracy, integrity, continuity and availability. This must be determined by various analysis techniques including failure mode and effects analysis (FMEA) and integrity assessment. Because of the high percentile requirements placed on integrity (as the parameter most directly related safety), it is unfeasible to measure system performance by demonstration (field trial). Realistic simulation informed by some field experience is usually employed. However, the current simulation-based approaches for receiver autonomous integrity monitoring (RAIM) performance assessment have a number of weaknesses including the use of coarse (large) spatial and temporal sampling intervals, loose definitions of error and geometric correlations, a lack of sampling of all geometries and the inability to account for critical points due to uncorrelated factors. This paper proposes a dynamic sampling method that takes account of these weaknesses, identifying dynamically only the required points for integrity performance assessment. Comprehensive simulations carried out to test the proposed approach for a single point, an area, and a non-precise approach (NPA) flight path to Gatwick airport in the United Kingdom show that the method can be effective in capturing all the points enabling a robust and reliable assessment of system integrity.

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