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The unsupported spans of heat exchanger and steam generator (SG) tubing are susceptible to fouling which can significantly degrade their thermal performance in the long term. Clogging of SG flow paths causes level fluctuation or even tube vibration that may initiate outer diameter cracking. Formation of hard scale on tube sheet causes denting and / or pitting. Unmitigated fouling or formation of hard scale can make it necessary to exchange the valuable component long before it would normally be necessary and costly unbudgeted repair outages are the consequence.


For heat exchangers and SGs chemical cleaning is the only way to remove accumulated deposits from tube sheet to top of bundle. Our secondary-side chemical cleaning processes restore heat transfer efficiency and extend operating life of the component by chemical mobilization, minimization and removal of deposits from heat exchangers and SGs. To obtain optimum cleaning results in SGs, the chemical cleaning processes are adapted to the nuclear power plant (NPP) specific history (water chemistry, material concept, blowdown system design) and the resulting individual prevailing conditions (deposit amount and constitution, deposit distribution, existing or expected corrosion problems).

 

Tailored solutions for each SG or heat exchanger:

  • Maintenance and preventative cleaning: Deposit Minimization Treatment (DMT)
  • Intermediate cleaning: Deposit Accumulation Reduction Treatment at High Temperature (DART HT)
  • Full scale and curative cleaning: High Temperature Chemical Cleaning (HTCC)
  • Chemical cleaning method developed by Steam Generator Owner’s Group (EPRI SGOG)
  • Deposit Accumulation Reduction Treatment at Low Temperature (DART LT)


Your Benefits

  • Restores heat transfer efficiency
  • Protects components and extends their operating lifetime
  • Ensures high plant availability
  • Efficient and proven chemical cleaning technology with low corrosion and associated risks
  • No or very low impact on outage duration
  • Each chemical cleaning application reconditions the heat exchanger or SG
  • The chemical cleaning process is tailored to the individual needs and requirements of each individual plant
  • Our international experience and expertise covers hundreds of SGs designed by different original equipment manufacturers

 

References

DMT:

France (2 NPPs in 2017), France (2016), France (2014), France (2013), France (3 NPPs in 2012), France (2011)

 

DART:

DART LT: the Netherlands (2017), Rumania (2006)
DART HT: Spain (2010), Spain (2009)

 

HTCC:

Argentina (2009), France (2 NPPs in 2008), France (4 NPPs in 2007)

Interested in Chemical Cleaning of Steam Generators and Heat Exchangers?

Andreas Drexler, Steffen Weiss, Neil Caris, Christoph Stiepani
AREVA’s toolbox for long-term best performance and reliable operation of nuclear steam generators
Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia – 2015, September 2-4, 2015, Anupuram, India

CANDU Reactors VVER Reactors CANDO VVER Westinghouse