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Technology Factsheet

AT1 Pilot Facility ATENA Remote Dismantling Machine

Category: Robotics > Dismantling and Retrieval > Bespoke System
Reference # : Model No :

The AT-1 (Atelier de Traitement) pilot facility, situated near Cherbourg on the AREVA NC La Hague site, was built to reprocess fuels from fast breeder reactors. The plant operated for 10 years, from 1969 to 1979. Final closure in 1979 was followed by a 12 month campaign of plant wash out and an 18 month period of systematic decontamination of the circuits.

The ATENA machine comprised an 11-metre remote controlled telescopic multi-jointed arm, which could retract into a very thick steel hood. The hood worked both as containment and as biological protection for the operators. The tip of the telescopic arm could be equipped with a cutting tool or with an MA 23 M or RD 500 type remote manipulator. On completion of the project, the ATENA machine was disposed of as waste.

Site:France
Industry:Nuclear
Size:Very Large (>100kg/200lb, >120cm/48in)
TRL:Operational (9)
TRL2:Operational (9)
Tether: *
Waterproof: *
Payload: *
Reach: *
Manipulator: *

Benefits

Limitations

Comments

As a result, the following techniques were tested and met with a fair degree of success:
- Remote dismantling of totally blind cells using the ATENA machine. This process enabled cutting of all the piping and equipment within 13 metres of the cell’s entry point.
- Development of the stainless steel modular panels used to make the air-locks and cells, and which can be recovered after cleansing,
- Remote cutting of a concrete wall using the ATENA machine and a diamond- wheel saw,
- Cleansing of the contaminated concrete walls using a semi-automatic process which reduced the doses absorbed by the personnel working in the cell.
- Cutting of sheet metal equipment using explosive cords. This process reduced the operator intervention time in the cell, and thus significantly reduced the doses absorbed by the personnel. However, it did increase the volume of the waste (airborne particulate spatter) and spread contamination.

The implementation of some of these techniques caused, and continues to cause, some financial and technical problems. Overall, however, the work was satisfactory.

The dismantling of the AT1 fuel reprocessing facility was a very educational, informative operation. The scenario selected and the technique used – combining a holder and a remote manipulator equipped with tools, working together in remotely– controlled operations – proved to be effective for the dismantling of large-sized blind cells to IAEA (International Atomic Energy Agency) stage 3, in very good radiological safety conditions.

Important aspects concerning the evolution in the ventilation and the aging of the electrical network, which had not been considered at the outset, appeared at the end of the dismantling work.

Lastly, the good control of purchasing and supplier selection on the La Hague site, for which there are very few approved suppliers, contributed to the satisfactory completion of the work.

The fact that the dismantling/cleansing was programmed over a period of approximately 20 years (after 10 years of operation) meant some of the elements which were required for the project had to be replaced and also necessitated major maintenance for some of the equipment which was an integral part of the installation, at dates which were relatively close to the end of the operations. This meant that these major maintenance or difficult replacement actions could have been avoided if the dismantling program had been shorter.

Operational Experience:

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