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Development of Technical Guidelines
Water Chemistry, Corrosion Control for Secondary Side of WWER
Negligence of water chemistry control contributed to the WWER SG degradations so significantly that SG replacements were necessarily performed. Thus, two Russia´s regulatory guides about water chemistry control had been issued. And many countries in Europe had spent a lot of efforts to improve NPP water chemistry and corrosion control. Now it is time to exchange practical information among MSs and summarize good practices in an Agency´s document, which will help to further enhance the water chemistry and corrosion control in Europe and to inform the new WWER operators in other parts of the world.
This document will describe the requirements and best practices about the secondary circuit water chemistry, various water chemistry regimes, hide-out return analysis, cooling and make-up water chemistry, application of chemistry index, water chemistry surveillance (manual and automated), corrosion and erosion degradations and control, etc.
Chemistry control is one of the most important disciplines and activities in NPP operation. WWERs are in operation in a number of Eastern European and Asian countries. Due to the development history, they have different national capabilities and in a number of cases different circuit chemistry guidelines, criteria and philosophies on control and management of water chemistry. The position with WWER guidelines is that there are only a limited consensus view among the different countries on the correct chemistry controls to apply, and in some cases the views may be very different and at odds with each other.
In contrast with this position, there is a more "unified" approach in PWRs. There are three major sets of chemistry guidelines: the EPRI guidelines, the VGB standards and the EDF specifications. It is believed that harmonized approaches to water chemistry of WWER would be helpful and experience of PWR water chemistry could be learnt to improve WWER water chemistry performance. The publication is expected in the 4th quarter of 2008.
References:
- High temperature on-line monitoring of water chemistry and corrosion control in water cooled power reactors, IAEA-TECDOC-1303, IAEA, Vienna (2002)
- New approaches for stable isotope ratio measurements, IAEA-TECDOC-1247, IAEA, Vienna (2001)
- Water chemistry and corrosion control of cladding and primary circuit components, IAEA-TECDOC-1128, IAEA, Vienna (1999)
- Influence of water chemistry on fuel cladding behaviour, IAEA-TECDOC-927, IAEA, Vienna (1997)