Advanced Graphite Trepanning Equipment (AGTE)
Inspection tool to assess the condition of the graphite cores in nuclear reactors.
Our client’s existing ‘New Graphite Trepanning Equipment’ (NGTE) was introduced in 2004 to support station plant lifetime extension planning. Its purpose was retrieving graphite samples from a reactor for analysis.
While NGTE was reaching the end of its design life it was being operated more frequently than the original design specification had foreseen. This carried the increased potential for this critical piece of equipment to fail whilst in service.
To mitigate this risk JFN set about to replace the existing NGTE with a modern graphite trepanning equipment solution. The new solution was compatible with the existing NGTE transportation containers and other site support services.
JFN designed, manufactured, tested and successfully commissioned a replacement known as the Advanced Graphite Trepanning Equipment (AGTE).
The system has now undergone extensive Site Acceptance Testing and has been successfully deployed in an Advanced Gas-cooled Reactor.
AGTE has been optimised to ensure it meets the requirements for a modern, integrated graphite trepanning solution that is capable of meeting the current elevated operating frequency. The AGTE consists of one Hoist, two Sample Transfer Flasks Trolleys, two Control Consoles and three Graphite Trepanning Tools (GTTs).
JFN worked closely with our site licenced clients to incorporate desired system requirements into the design, including fail safe and recovery functions, and an intuitive operator interface via the control consoles.
The whole system is housed in a high-integrity, stainless steel, ventilated containment enclosure. This prevents the spread of contaminated graphite particles to the reactor Pile Cap. This containment structure provides the same functional requirements as those for the high integrity, stainless steel, process cabinets / gloveboxes.
A hoist is used to house and deploy the GTT into the reactor. It also receives and transfers samples from the GTT to Sample Transfer Flasks. The hoist contains a number of electrical control cabinets linked to the main control console via deck leads and a pneumatics panel and vacuum unit, providing supply to functions within the GTT and hoist. Cameras within the hoist and local to critical mechanisms provide detailed views on the console monitors of the graphite sample transfer process.
The console is a large control panel contained within a wheeled framework. It is connected via deck leads to the hoist and contains the PLC used to control and monitor the system. User interfaces are via an human machine interface, including two monitor screens (for camera views) and video recorder, as well as a small selection of push buttons and a joystick for critical hoist and GTT operations.
The GTT is a long cylindrical tool consisting of five main sections, used to obtain samples of graphite from AGR reactors.
- Suspension unit contains the wire rope and umbilical connections
- Clamp unit contains six clamp modules to hold the GTT within the reactor channel
- Azimuth unit, used to rotate the bottom section of the GTT
- Trepanning unit containing the trepanning cutter and drives
- Nose unit containing an air-knife (for channel flow reversal), camera and microphone
The sample transfer flask trolley is a wheeled framework designed to house Sample Transfer Flasks for transport of graphite samples. The trolley is able to be manually raised and lowered to interface with the Sample Transfer Unit on the Hoist using power jacks mounted to its frame.
