[en] In 2006, EDF identified on several PWR units some broached hole blockages on the upper Steam Generator (SG) Tube Support Plates (TSP). The consequences on SGs circulation ratio and the risk of the SG cracking tubes led EDF to implement a program of counteractions. TSP blockage often occurs in association with secondary fouling due to the surface degradation of the materials on the secondary circuit. Thus, EDF has defined a two-level strategy to improve the SGs operating conditions: -) the implementation of curative remedies to remove oxides deposits in SGs e.g. chemical cleaning, -) the removal of the copper alloys materials of the secondary circuit to implement a high pH AVT (9.60) as a preventive remedy along with soft chemical cleaning to maintain satisfactory SGs performances and safety operating conditions. Within 2007-2009, EDF applied SG chemical cleaning on 12 PWR plants (six with the AREVA inhibitor free high temperature process HTCC and six others with the low temperature EPRI/SGOG process by Westinghouse). Both the HTCC and the EPRI/SGOG processes led to good results regarding the deposit removal and the TSP blockage reduction. Feedback about the corrosion of carbon steel surfaces is more favourable for the EPRI/SGOG process than for the HTCC process, which led locally to a loss of thickness of several hundred microns. Moreover, the excessive release of gaseous chemicals (ammonia) in the environment was also an important issue for the AREVA process. Therefore four new applications of the EPRI/SGOG cleaning process are foreseen in 2010-2011. Meanwhile, EDF is carrying out a program to remove of all copper alloy exchangers in the secondary circuit, in order to implement a high pH AVT, which offers proven benefits on SGs fouling and TSP blockage, as well as an efficient way to mitigate carbon steel flow accelerated corrosion damages Since the removal of brass condenser is not yet possible for some units for environmental or sanitary reasons, EDF hopes to implement an intermediate pH AVT. This is until a solution is found to improve the situation and prevent cleaned SGs to quickly being confronted with the same issues of oxides deposits. (authors)