Proceedings of the 11th international conference on NDE in relation to structural integrity for nuclear and pressurized components

This Conference, the eleventh in a series on NDE in relation to structural integrity for nuclear and pressurized components, was held in Jeju Island, Korea, from 19th to 21st of May 2015. The scientific programme was co-produced by the European Commission’s Joint Research Centre, Institute for Energy and Transport (EC-JRC/IET). Previous conferences were held in Amsterdam in October 1998, New Orleans in May 2000, Seville in November 2001, London in December 2004, San Diego in May 2006, Budapest in October 2007, Yokohama in May 2009, Berlin in September 2010, Seattle in May 2012, and Cannes in October 2013. All were highly successful in the quality and scope of the technical programs and the number of attendees from all countries with an interest in the structural integrity of nuclear and pressurized components. The overall objectives of the Conference were to provide an up-to-date assessment of the development and application of NDE and to allow technical interchange between experts on an international basis. The Conference covered all aspects of this extremely important subject, with special regard to the links between structural integrity requirements and NDE performance. The development of improved NDE systems and methods was highlighted. Determination of NDE performance by development of qualification systems or performance demonstration, and experience of their use in practice was prominently featured.JRC.F.5-Nuclear Reactor Safety Assessmen

Proceedings of the 11th international conference on NDE in relation to structural integrity for nuclear and pressurized components

This Conference, the eleventh in a series on NDE in relation to structural integrity for nuclear and pressurized components, was held in Jeju Island, Korea, from 19th to 21st of May 2015. The scientific programme was co-produced by the European Commission’s Joint Research Centre, Institute for Energy and Transport (EC-JRC/IET). Previous conferences were held in Amsterdam in October 1998, New Orleans in May 2000, Seville in November 2001, London in December 2004, San Diego in May 2006, Budapest in October 2007, Yokohama in May 2009, Berlin in September 2010, Seattle in May 2012, and Cannes in October 2013. All were highly successful in the quality and scope of the technical programs and the number of attendees from all countries with an interest in the structural integrity of nuclear and pressurized components. The overall objectives of the Conference were to provide an up-to-date assessment of the development and application of NDE and to allow technical interchange between experts on an international basis. The Conference covered all aspects of this extremely important subject, with special regard to the links between structural integrity requirements and NDE performance. The development of improved NDE systems and methods was highlighted. Determination of NDE performance by development of qualification systems or performance demonstration, and experience of their use in practice was prominently featured.JRC.F.5-Nuclear Reactor Safety Assessmen

Novel Approaches for Nondestructive Testing and Evaluation

Nondestructive testing and evaluation (NDT&E) is one of the most important techniques for determining the quality and safety of materials, components, devices, and structures. NDT&E technologies include ultrasonic testing (UT), magnetic particle testing (MT), magnetic flux leakage testing (MFLT), eddy current testing (ECT), radiation testing (RT), penetrant testing (PT), and visual testing (VT), and these are widely used throughout the modern industry. However, some NDT processes, such as those for cleaning specimens and removing paint, cause environmental pollution and must only be considered in limited environments (time, space, and sensor selection). Thus, NDT&E is classified as a typical 3D (dirty, dangerous, and difficult) job. In addition, NDT operators judge the presence of damage based on experience and subjective judgment, so in some cases, a flaw may not be detected during the test. Therefore, to obtain clearer test results, a means for the operator to determine flaws more easily should be provided. In addition, the test results should be organized systemically in order to identify the cause of the abnormality in the test specimen and to identify the progress of the damage quantitatively

Fatigue of dented pipes

A dented pipe fails either through being punctured or by fatigue damage accumulation due to internal pressure fluctuation. Increasing the wall thickness may prevent these failures but is impractical. As a pipe is punctured, transmission services must be cut off and repair processes have to be made immediately. However, when a dent depth is not large enough to puncture the pipe, the pipe can safely continue in service for a long time until a fatigue crack initiation occurs. Therefore, the fatigue life assessment has attracted much attention in the pipe industries for economic and safety reasons. The severe tensile residual stress concentration and the large plastic strain deformation in the dented region are the main causes of the pipe failure due to fatigue damage. Accurate calculation and prediction of the residual stress and variations resulting from internal pressure fluctuation can lead to safety assessments and prediction of the remaining life of the dented pipe. Due to the complex nature of the contact process, the deformed pipe geometry and the elastic-plasticity, analytical approaches are incapable of obtaining stress solutions. Therefore, FE modelling is employed in the present work. Experimental tests are employed to investigate the indenter force-dent depth behaviour which can be compared with the FE solutions to confirm and validate the FE models. The rigid perfect elastic-plastic limit load method and an energy-based method are also used to analytically calculate the limit load and the indenter force/deflection relationship of indented rings to predict damage. Two dimensional FE modelling is performed to calculate the contact and residual stress and strain distributions on the outer, inner surfaces and through the wall thickness. These FE solutions show that high stress concentrations occur in the indented region, which give the potential for fatigue damage. As the 2D FE modelling requires only limited resources, the indenter size and indentation position can be changed to analyse their effects on stress and strain distributions in the indented region. This forms the foundation of later 3D FE modelling. Stress sensitivity and the validation of shell models are investigated and confirmed through the 2D and 3D FE modelling and by comparing experimental test data with the FE solutions. Based on this work, the decision is made to use shell element modelling to perform the residual stress and stress range calculations in a 3D pipe. Semi-empirical formulations are developed to predict stress and stress range values if the residual dent depth, the pipe and indenter geometries, material property, internal pressure and pressure range are known. These FE solutions and semi-empirical formulae can be used to calculate the stress range and mean stress

Fatigue of dented pipes

A dented pipe fails either through being punctured or by fatigue damage accumulation due to internal pressure fluctuation. Increasing the wall thickness may prevent these failures but is impractical. As a pipe is punctured, transmission services must be cut off and repair processes have to be made immediately. However, when a dent depth is not large enough to puncture the pipe, the pipe can safely continue in service for a long time until a fatigue crack initiation occurs. Therefore, the fatigue life assessment has attracted much attention in the pipe industries for economic and safety reasons. The severe tensile residual stress concentration and the large plastic strain deformation in the dented region are the main causes of the pipe failure due to fatigue damage. Accurate calculation and prediction of the residual stress and variations resulting from internal pressure fluctuation can lead to safety assessments and prediction of the remaining life of the dented pipe. Due to the complex nature of the contact process, the deformed pipe geometry and the elastic-plasticity, analytical approaches are incapable of obtaining stress solutions. Therefore, FE modelling is employed in the present work. Experimental tests are employed to investigate the indenter force-dent depth behaviour which can be compared with the FE solutions to confirm and validate the FE models. The rigid perfect elastic-plastic limit load method and an energy-based method are also used to analytically calculate the limit load and the indenter force/deflection relationship of indented rings to predict damage. Two dimensional FE modelling is performed to calculate the contact and residual stress and strain distributions on the outer, inner surfaces and through the wall thickness. These FE solutions show that high stress concentrations occur in the indented region, which give the potential for fatigue damage. As the 2D FE modelling requires only limited resources, the indenter size and indentation position can be changed to analyse their effects on stress and strain distributions in the indented region. This forms the foundation of later 3D FE modelling. Stress sensitivity and the validation of shell models are investigated and confirmed through the 2D and 3D FE modelling and by comparing experimental test data with the FE solutions. Based on this work, the decision is made to use shell element modelling to perform the residual stress and stress range calculations in a 3D pipe. Semi-empirical formulations are developed to predict stress and stress range values if the residual dent depth, the pipe and indenter geometries, material property, internal pressure and pressure range are known. These FE solutions and semi-empirical formulae can be used to calculate the stress range and mean stress