PT02 is a completely re-designed new version of the capsule-based target transfer system, which provides for one-way transfer of solid target disks irradiated in the Nirta Solid Compact® target station into hot cells for further radiochemical processing.
The system uses a powerful blower for generating under-pressure, which transfers the sealed and locked capsule with the target disk. This way the system is inherently safe, i.e. radioactive particles released from the target cannot enter the atmosphere of the installation.
As compared to the previous PT01 model, the all new PT02 version is significantly smaller, and instead of an electrical motor, the robotic capsule handling station uses a pneumatic indexing mechanism for positioning of the capsules. Moreover, the capsule receiving station to be installed in the hot cell can be now configured for handling with the left or right ball-tong manipulator, depending on user preference. Finally, a capsule switching station can be integrated into the transfer system, creating complex networks of capsule transfer in case the site operates more than one target station.
The system has five main sub-systems: the robotic target handling station, the control cabinet with the PLC-based control and safety system, the blower station, capsule receiving stations installed in hot cells for receiving the capsules with the irradiated target disks, and optional capsule switching stations.
The purpose of the robotic target handling station is to open the transport capsule, position it in such a way that the target disk released from the target station falls into the open capsule, close the capsule, and release the capsule into one of the five transport tubes, guiding the capsule with the target into the appropriate hot cell.
It contains the PLC and the input/output interfaces controlling the operation of the transport system. The individual components of the system are connected to the control system with appropriate cables. There is a touch screen built into the front door of the control cabinet, through which the control system communicates with the operators.
The control system allows for fully automatic operation of the system, and alternatively for manual operation of individual subsystems. There are a number of interlocks and safety features built into the control system, ensuring that operations, which could lead to damage of the hardware or radiation hazard are not executed.
The control system of the pneumatic target transport system can be connected to the control system of the cyclotron, which will allow to the cyclotron operator to initiate the transfer from the control screen of the cyclotron. The control system can also communicate with the individual hot cells, exchanging safety interlock signals in order to minimize radiation hazards and accidents.
The control system can detect any abnormal situation, since it has a number of sensors following the status of the hardware. These abnormal situations will trigger alarms, which will be communicated to the operators through the screen of the touch panel.
The blower station consists of a powerful blower and a HEPA filter. The blower is providing the necessary under-pressure required for the transfer of capsules from the robotic target handling station to the receiving stations installed in hot cells.
The air, which is sucked through the transport tubing is passing through the HEPA filter before entering the blower, thus debris potentially entering the transport system cannot damage the blower. Moreover, the HEPA filter will retain radioactive particles preventing the contamination of the environment in case such particles enter the transfer tubing.
Capsule switching stations allow for connecting several input tubes to one output tube, and/or for connecting one input tube to several output tubes. This way, one can for instance connect two target stations to one hot cell for receiving the capsules.
The capsule receiving stations are installed in hot cells and their role is to lock the capsules upon arrival allowing the operators to remove the capsules from the transport system for further processing. These stations have special doors operated by pneumatic cylinders through a toggle clamp. The doors can be open and closed by pressing the appropriate push buttons on the remote controls at any time, provided that the airlock is closed and that there is no capsule transfer in progress. The toggle clamp locks the door securely in closed position even if there is an interruption in compressed air supply, thus the hermetic isolation of the hot cell’s containment is never compromised
The airlocks, which are integral parts of the receiving stations will ensure that the interior of the hot cell remains always isolated from the environment, since the two ball valves forming the airlock are open only while the capsule is flying through them.
An interlock built into the safety system prevents opening the door of the receiving station if the airlock is open. Similarly, an interlock is preventing the opening of the airlock as long as the door of the receiving station in the hot cell is open. This ensure that the atmosphere of the hot cell is never mixed with the air in the transfer tubes and that the under-pressure in the hot cells is never compromised by leaks through the transfer tubes.