The recent revision of the VGB Water Chemistry Guidelines was issued in 2005 and published in the second half of 2006.These guidelines are based on the primary and secondary side operating chemistry experience with all Siemens designed pressurized water reactors gained since the beginning of the 1980s.These guidelines coverFor the primary side chemistry- Modified lithium boron chemistry- Zinc chemistry for dose rate reduction,- Enriched boric acid(EBA)chemistry for high duty core designFor the secondary side chemistryHigh all-volatile treatment(AVT)chemistry(high pH operation)Oxygen injection in the secondary sideEspecially for the secondary side chemistry,compared with the water chemistry guidelines of other organizations worldwide,these Guidelines are less stringent,providing more operational flexibility to the plant operation,and can be applied for all new designs of steam generators with egg-crates or broached hole tube supports and with I 690TT or I 800 tubing materials.This paper gives an overview of the 2006 revision of the VGB Water Chemistry Guidelines for PWR plants and describes the fundamental goals of water chemistry operation strategies.In addition,the reasons for the selected control parameters and action levels,to achieve an adequate plant performance,are presented based on the operating experience.
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