OECD-NEA, CSNI Working Group on the Integrity and Ageing of Components and Structures (WGIAGE)


Workshop on Non-destructive Evaluation of Thick-walled Concrete Structures

Prague, Czech Republic
17-19 September 2013

Organized by ÚJV Řež, a. s., Czech Republic



Introduction

Concrete structures are essentially passive components under normal operating conditions, but play a key role in mitigating the impact of extreme or abnormal operating events and external hazards. Structural components are somewhat plant specific, may be difficult to inspect and may be a limiting factor for plant life since they are mostly irreplaceable. Structures are subject to time-dependent variation of material properties under the influence of environmental stressors and ageing factors that may impact their ability to perform their safety function. As NPPs age, assurance needs to be provided that the capacity of concrete structures to mitigate extreme events has not deteriorated unacceptably.

The objective of this workshop was to present and discuss the state-of-the-art techniques for the integrity assessment of concrete structures, and to recommend areas where further research is needed.

Aim and scope of the workshop

The objective of the workshop was to review existing methods for non-destructive evaluation of NPPs thick-walled concrete structures and to present state-of-the-art techniques for the integrity of concrete structures, aiming to detect voids and cracks in concrete and to detect passive (rebars) and active (tendons) reinforcing items.

The first workshop was held in 1997 in UK at Risley where the development priorities of NDE of concrete structures in NPPs were identified. The second workshop was held in 2008 in Prague on Ageing Management of Thick-Walled Concrete Structures, Including ISI, Maintenance and Repair and Safety Assessment in view on Long-term Operation. The discussion focused on non-destructive examination of NPP containment structures presenting challenges different from conventional civil engineering structures due to several aspects, such as:

  1. wall thickness that could exceed one meter; structures often have increased steel reinforcement density with more complex detailing;
  2. the number of penetrations or cast in place items; and accesibility may be limited due to presence of liners or other components;
  3. harsh environment or structures located below ground.

The principal domains were:


Last reviewed: 25 November 2013