REMOTE CONTROLLED CRUD REMOVAL BY USE OF IN-PIPE MANIPULATORS


11th International Conference on CANDU® Maintenance and Nuclear Components - 2017 Oct. 01-04

Presented at:
11th International Conference on CANDU® Maintenance and Nuclear Components
2017 Oct. 01-04
Location:
Toronto, ON Canada
Session Title:
Strategies to Mitigate Component Degradation

Authors:
H. Damies (AREVA GmbH)
F. Hudelmaier (AREVA GmbH)
E. Seeberger (AREVA GmbH)
  

Abstract

The Emergency Coolant Injection system is a critical special safety system that is poised to activate in the event that a Loss of Coolant Accident (LOCA) occurs within one of the units. Since there is not a continuous flow throughout the system, during the years of operation radioactive crud can built up in low points and valve internals in the system causing high dose rate areas. Due to the high field intensity (radiation dose rate at the crud up to 70 REM/hour) a cleaning can’t be done manually. Therefore remote controlled tooling must be used.
The AREVA solution is tailor made with specific equipment arrangement. The crud removal inside the ECI piping is performed completely remote controlled by application of proven AREVA in-pipe manipulator technology. An adjustable vacuum generator ensures a continuous high efficient crud removal via swiveling suction nozzle. The crud is transferred from the suction line straight into the water seal of the special water filter element. A swirl generator and a special strainer arrangement are ensuring a separation of the solid curd inside the water seal. Due to the gravitation effect the solid curd moves to the center of the cone bottom where the drain line is located. After remote controlled opening of the drain line the crud together with the water is discharged automatically to a shielded waste collection barrel. A special solid filter in the shielded barrel allows a separation of the water from the solid parts of the crud. The separated water can be re-used in the special water filter element.

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