Ansaldo Nuclear has supplied a bespoke robot to extract and recover 2000 drums of radioactive waste from difficult-to-access locations at the Caorso nuclear power plant, now being decommissioned in Italy.
Caorso is a single-unit 860MWe boiling water reactor plant, which began commercial operation in 1981 and was permanently shut down in 1990.
The 2014 decommissioning licence includes a key project to treat and condition 860 tonne of radioactive ion exchange resins and sludges held in two temporary storage buildings at plant. This waste represents more than 90% of the contamination inventory at Caorso, Ansaldo said.
The aim is to transform this waste into final packages, with a volume reduction factor of 10 releasing the two storage buildings for refurbishment.
Ansaldo Nuclear was contracted in 2015 by Italy's Società Gestione Impianti Nucleari SpA (Sogin) to retrieve, transport, treat and condition the spent resins and sludges as part of a joint venture with JAVYS.
The teams will transport 5600 200kg drums of Caorso's radioactive waste to the storage facility at Jaslovské Bohunice in Slovakia, where it will be stabilised via incineration and finally conditioned. The first of 33 expected shipments took place in January.
So that the project could begin in January 2020, Ansaldo Nuclear conceptualised, designed, manufactured, installed and operated a bespoke Machine Retrieval System (MRS) robot to retrieve 2000 drums of radwaste stored in various niches within Caorso’s temporary storage facilities.
"The extent of the logistical challenge presented by this phase of the Caorso decommissioning project cannot be underestimated,” said Francesca Maggini, project engineer and bid technical manager at Ansaldo Nuclear. “The unique nature of nuclear decommissioning means it is important to face each decommissioning project as an entirely new challenge. You cannot simply repeat the successes of the past - you must pioneer and develop bespoke solutions in order to see the best results," she added.
The MRS robot used to retrieve, verify, seal and pack the radioactive drums, took six months to build and install. It is controlled remotely, with a second operating system in place in case of system failure, and is capable of self-recovery in the event of earthquakes or other external safety issues.
“One of the key challenges was that we were unable to access the area to take detailed measurements, so the robot had to be constructed to be as compact as possible to allow enough clearance," said Francesco Orzelli, designer and structural analyst at Ansaldo Nuclear, who was instrumental in developing the robot's design.
Orzelli said a fully-functioning, 3D model, complete with all mechanical components was produced first, which allowed Ansaldo to develop a "small machine with significant capabilities.”
He added, "Ansaldo Nuclear not only had to manufacture and install an automated retrieval robot, but develop the solution as well." This process took two years.
Photo: Ansaldo Nuclear’s custom-made robot for the decommissioning project at Caorso Nuclear Power Plant. I’ve also attached a range of photographs of the robot.