Home » Our services » Technologies » Maintenance » Steam Generator Maintenance: Secondary side servicing

Steam Generator Maintenance: Secondary side servicing

Sludge removal from steam generators using high pressure lancing

Steam Generator Maintenance: Secondary side servicing


Cleaning by high-pressure lancing of the interior of the lower secondary shell (primary/secondary exchanger) of French PWR steam generators:

  • Confined space exposed to high radiation
  • Very restricted access to the interior of the steam generator and tube bundle
  • Penetration of the high pressure lance inside the tube bundle
  • Recovery and filtration of the sludge removed from the steam generator

Service provided

Design and supply of 5 C.R.O.T.A.L. systems:

  • Range of lancing pressure: 120 to 300 bars
  • Automated guidance of the movements of the high-pressure lance inside the tube bundle, along a transversal rail passing through the steam generator.
  • High-pressure lance made of a special, shape-memory metal alloy with the flexibility to enrol itself around a reel, thus allowing movement across the entire generator with a single, seamless length.
  • Drainage of the debris dislodged from the tube bundles using auxiliary water jets
  • Double filtration of effluents
  • Televisual inspection of the state of cleanliness of the steam generator using remote-controlled inspection devices
  • On-site deployment
Equipement CROTAL


Country: France
Client: EDF UTO

Project Details:

  • Duration: 2010-2017
  • Scope: all EDF 900 and1 300 Mwe units
  • Intervention on primary circuit
  • Project team: 4 staff members
  • Site operation team: 70 staff members
  • Duration of one site operation: 3 weeks


36, boulevard de l’Océan - CS 20280
13258 Marseille Cedex 9 - France
Phone: +33 (0)4 91 29 18 10
Fax: +33 (0)4 91 29 18 58
ONET SA - RCS B 059 801 324 Marseille
Video of chemical cleaning of the steam generators