HALCW resin tank has been replaced. The old tank is stored in middle-west silo now. The field on old resin tank bottom is about 3.5 msv/ hr(on contact). By shielding it into silo and putting two lead blankets on the top cover of the silo,The general field 1 feet above this silo is 25usv/hr. And, The field around the silo area are less affected. This old tank will stay there as long as possible. For the new resin tank during preparation, It was found that on return line side, the 1.25" pipe thread plug with return line tube was very difficult to be installed onto the female thread adapter which is welded onto to tank body. It was jammed in half way of threading onto tank at manufacturer. This plug was removed out first and inspected. The first and second male threads were galled. Maico repaired the thread on a lathe. The female thread on the tank was tapped. A tight spot was found during the tap. After that, the return line plug could be installed onto the tank properly. The new tank was installed into the vessel and connected back to HALCW system. Water are refilled into new tank. During refill air were trapped into the system. This caused pump restarting problem. By Several times of starting up the pump, stopping the pump and venting, Most air were breathed out of system. Finally,The system was restarted by supply water to ITW( without module) only. ITE and resin can circuits were brought back to system after that without problem.
Before removing the old tank, We drained water out of old tank to decay tank. Since the resin tank is largely filled with resin, and water are soaked into resin, we only can drain out less than 10 liters water out of tank. Also, The drain caused some part of return line on pumps have to been drained. This is the main reason air was trapped in system during the new resin tank water refilling. For the future replacement, we should not drain water in old tank. It does not worth to do it.
Attach TH HALCW resin tank replacement procedure here.
2022-02-17 reload replacement procedure and draining schematic. |