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


IAEA peer review mission on Mechanical Components Ageing Management Programme for Paks Nuclear Power Plant, 9–14 November 2008, Paks, Hungary


The objective of the service is to review the current status of the reviewed area in the plant based on related IAEA Safety Standards and guidance documents, and internationally accepted practices. The mission addressed the review of the plant that is to be submitted to Hungarian Atomic Energy Agency (HAEA).

Paks NPP has already submitted their Program of Long Term Operation to HAEA, and they will fully implement their programmes in the timeframe required for their final application for license renewal for Paks NPP Unit 1 in 2011.

IAEA peer review mission on Mechanical Components Ageing Management Programme for Paks Nuclear Power Plant, 9–14 November 2008

Upon the invitation of the HAEA, a peer review mission of the selected parts of mechanical components ageing management programme (AMP) for Paks Nuclear Power Plant (NPP) was provided from 9 to 14 November 2008 at Paks NPP in Hungary. The mission was conducted under the IAEA Technical Cooperation Project HUN 4/016 "Renewal of the Licence for the Paks Nuclear Power Plant". Two international experts were invited to perform an in-depth review.

The evaluation reports on Mechanical Components AMP in Paks NPP are divided into two groups:

  • Degradation mechanism driven AMPs.
  • Component-specific AMPs – the scope can be divided into two subgroups:
    • AMPs dealing with the separately managed major components, and
    • AMPs representing commodity groups of components.

Currently, there are many AMPs already developed at the plant. The whole set of AMPs, which represents around 250 particular AMPs, will be completed in 2009.

The ageing management programme in Paks NPP is based on technical reports developed by TSOs which were driven by the need to follow the ten elements of USNRC NUREG-1801 "Generic Ageing Lessons Learned" (GALL) report.

The structure of all component-specific AMPs follows the philosophy of the GALL report. Each component-specific AMP consists of 10 chapters:

  1. Determination of degradation processes, structural locations sensitive to ageing
  2. Measures mitigating and preventing the ageing processes
  3. Parameters to be inspected
  4. Detection of ageing effects
  5. Monitoring, trend monitoring, condition evaluation
  6. Criteria for compliance
  7. Corrective actions
  8. Feedback, increase of effectiveness of the ageing management program
  9. Administrative inspection - Quality assurance, coordination, documentation
  10. Operational experience feedback

The Team has selected the topics, following the scoping and screening procedures, from more than a hundred of particular AMPs and other relevant documentation:

  • Specific ageing management programme documents of mechanical components
  • Degradation mechanism oriented programmes
  • Time limited ageing analyses on pressurized thermal shock (PTS) events and fatigue
  • Thermal fatigue and environmentally assisted fatigue
  • Steam generator ageing
  • Guidelines by the regulator
  • Reactor pressure vessel (RPV) embrittlement

The following areas have been identified as a good performance:

  • The PTS calculations which have been done for the Paks RPV seem to be at a level of the state-of-the-art in this field.
  • The ageing management database looks like a comprehensive document which can be very helpful for maintaining knowledge about ageing management.

The AMP documents for the major components provided comprehensive discussion of strategies for ageing management. It has been found that:

  • Current operational and maintenance arrangements are adequate for timely detection of any significant ageing degradation.
  • For activities intended to detect the effects of ageing, operating experience involving identification of ageing degradation prior to loss of intended function indicates effectiveness of the activities.
  • For preventive activities, a history of plant operation without identifying the specific ageing effect indicates effectiveness of the preventive actions.

References:

  • Guidelines for peer review of long term operation and ageing management of nuclear power plants (to be published), IAEA, Vienna (2009)
  • Safety guide on ageing management (to be published), DS 382, IAEA, Vienna (2009)
  • Safe Long Term Operation of Nuclear Power Plants, IAEA-SRS-57 , IAEA, Vienna (2008)
  • Safety Aspects of Long Term Operation of Water Moderated Reactors Recommendations on the Scope and Content of Programmes for Safe Long Term Operation, IAEA-EBP-SALTO, Vienna (2007)
  • Plant Life Management for Long Term Operation of Light Water Reactors, IAEA-TRS-448, IAEA, Vienna (2006)
  • Periodic Safety Review of Nuclear Power Plants, Safety Standards Series Safety Guide No. NS-G-2.10, IAEA, Vienna (2003)