Third International PLiM Conference, 14-18 May 2012, Salt Lake City

Nuclear Power Engineering with Sights and Sounds Nuclear Power Engineering with Sights and Sounds

Plant Life Management (PLiM)
for Safe Long Term Operation (LTO)

Technical Cooperation Projects Activities


National Workshop on Steam Generator Maintenance and Replacement for Plant Life Management Programme of Embalse Nuclear Power Plant, 31 October - 2 November 2007, Embalse, Argentina


Embalse Nuclear Power Plant (ENPP), CANDU 6 type with 648 MW(e) output, began operation in 1983. In the last 10 years it has shown an excellent performance with an average capacity factor of 88.3%. As the end of the design life of Embalse NPP is foreseen for 2011, ENPP’s life extension was decided based on excellent performance. The effective plant life management programmes are being prepared for life assessment and condition assessment for beyond design life operation. Especially replacement of steam generator (SG) and large scale fuel channel replacement (LSFCR) are planed in 2011 for ENPP’s life extension. The workshop held from 31 October–2 November 2007 was focused on SG effective maintenance before replacement of SG and strategy of replacement of SG.

The maintenance and replacement of steam generators, presentation and discussion are divided into two parts as follows:

1. Approaches to mitigate steam generator before replacement of SG, and Replacement of SGs.

  • Maintain reducing secondary side environment to reduce corrosion of carbon steel
  • Inhibits formation of magnetite layer which could increase potential for flow assisted corrosion
  • Water lancing to remove deposits at tube support and hard sludge at the tube sheets
  • Engineering assessment and finite element analysis and engineering assessment to determine impact of support degradation on tubes
  • Flow induces vibration (fretting), tube pinching, fatigue

2. Replacement of steam generators (SGs).
In the strategy report for replacement of SGs, the following main issues should be included:

  • Component supply scope
  • Ground transportation on site
  • Need for specific temporary facilities on site
  • Need for temporary containment opening/closure
  • Hoisting of the component ionside the containment building
  • Civil works inside the containment building

References:

  • Heavy Component Replacement in Nuclear Power Plants: Procedure and Experience, NE Series No. NP-T-3.4, IAEA, Vienna (2008)
  • Plant Life Management for Long Term Operation of Light Water Reactors, IAEA-TRS-448, IAEA, Vienna (2006)
  • Assessment and Management of Ageing of Major Nuclear Power Plant Components Important to Safety: Steam Generators, IAEA-TECDOC-981, IAEA, Vienna (1997)