FR2793065A1 - Nuclear power station ion exchange resin de-watering, drying and treatment comprises use of collecting vessel for dispersion or suspension of water and resin - Google Patents

Abstract

The process comprises transferring resins, after drying, from a drying vessel (4) into a storage container (24). The water and resins to be pumped are dispersed or suspended in the collecting vessel (1), with the dispersed material fed directly to the drying vessel (4), and the water recovered from the storage vessel sent to the collecting vessel. The process comprises transferring resins, after drying, from a drying vessel (4) into a storage container (24). The water and resins to be pumped are dispersed or suspended in the collecting vessel (1), with the dispersed material, comprising ca. 30% resin and 70% water, fed directly to the drying vessel (4), and the water recovered from the storage vessel sent to the collecting vessel. The water drawn from the drying vessel is passed to an intermediate reservoir (10) and sent from it to the collecting vessel, to a dispersion feed duct (3) and to a filter (8) counter-flow rinsing pipe (12). The water evaporated during the drying process is fed, after condensing, to the intermediate reservoir. An Independent claim is also included for the apparatus for the above process.

Description

Method and device for draining, drying and packaging

  The present invention relates to a process for the draining, drying and conditioning of ion exchange resins originating from a nuclear power station and undergoing, in the latter, an intermediate storage in a collecting tank. , the resins being, after drying, transferred from a

  drying tank in a storage container. The invent-

  tion also relates to a device for the

implementation of this process.

  Up to now, the ion exchange resin which is in the collecting tank of the nuclear power plant has undergone intermediate storage in drums. After accumulation of a determined number of barrels, these barrels are opened by remote control and, by gripping and lifting devices also remotely controlled, the contents of the barrels are introduced into a drying tank

  diverging upwards in the form of a funnel. The mani-

  Pulation of the barrels requires considerable means of remote control. After closing the filled drying tank, the tank is heated and stirred by an agitating device. During the drying process,

  the water in the contents of the tank evaporates

  pore, and is recovered as condensate at

the outside of the tank.

  The object of the present invention is to provide a method and a device for draining, drying and

  simpler and less expensive packaging.

  According to the process according to the invention, a dispersion or suspension of water and resin is maintained in the collecting tank, capable of being pumped, the dispersion is sent directly to the drying tank and it is returned to the collecting tank. 'water

  evacuated from the drying tank.

  Thus, the evaporated water, recovered in the form of condensate, remains in the system (circuit) of the plant. These provisions make it possible to omit the intermediate stage comprising the drums which must be filled, stored and then be emptied into the drying tank. In addition, due to the recycling of the water recovered during the drying process, there is no need to decontaminate

  this water, which stays in the system.

  Preferably, the water recovered from the drying tank is brought to an intermediate tank from which partial flows are diverted to the collecting tank, to a supply line for

  dispersion and to a counter flushing line

  current from a filter on the water outlet of

the drying tank.

  So that the water recovered in the form of vapor during the drying process also remains in the system, this water is also, after condensation,

  sent to the intermediate tank.

  Preferably, the dispersion is composed

  about 30% resin and about 70% water.

  The device for implementing the method

  is distinguished by the fact that the above-mentioned drying tank

  tible to be heated is a closed tank into which opens a supply or dispersion line, capable of being connected to the collecting tank. From the drying tank, a water evacuation pipe also leads to the collecting tank and a steam evacuation pipe leads to a condenser. On the lower side of the drying tank there is a sampling tube for the dried resin. Moreover,

  a screw conveyor is preferably mounted inside

of the drying tank.

  The water evacuation pipe which starts from the lowest point of the drying tank ensures rapid drainage of the drip water from the drying tank, since this water evacuation

being accelerated by a pump.

  Preferably, a counter-current rinsing line for a filter mounted in the water discharge line is connected to the latter,

  between the filter and an intermediate tank.

  The vapor discharge line preferably leads to a condenser from which the

  condensate is sent to the intermediate tank.

  Below the drying tank, a conveyor can be arranged for the storage container receiving the dried resin. After filling this storage container through the tubing

  resin sample from the drying tank, this

  can be brought by the transporter to a disposal

closure of the container.

  The part of the device comprising the draining and drying can preferably be arranged in a

  container. In this case, the drying tank, the tank

  see intermediate, the condenser, the connecting lines between these elements as well as the control and regulation devices are arranged inside the container, which, as a mobile device, can be transported to the place of use and can , at the interfaces, be connected to the collecting tank of the nuclear power plant. The dispersion supply line and the water return line to the collecting tank have in this case

  connection and the conveyor is connected amo-

  visible to the container, below the latter.

  Referring to the appended diagrammatic drawing, an embodiment of the method according to the invention and of the device for implementing this method will be described below. in the drawings: FIG. i represents the diagram of the drainage and drying system; - Figure 2 is a side view, partially in section, of the device installed in a container; and - Figure 3 is a top view, partially in

section, of the container of figure 2.

  FIG. I illustrates a collecting tank 1 of a nuclear power station not shown in detail,

  tank in which there is a dispersion or suspension

  about 30% ion exchange resin, hereinafter called resin, in about 70% water. The resin introduced for a prolonged period into the collecting tank 1 arrives via a coupler connection 2 in a supply line 3 and from there directly into a drying tank 4. During the drying process, a screw conveyor 6 arranged in the drying tank 4 and driven by a motor 5 rotates around its axis,

  following a continuous rotational movement or a movement

  pendulum. The drying tank 4 has a slight slope from the right side to the left side, and here has a water outlet so that the excess water can be removed by a water discharge pipe 7 from this exit, on the lower left side. After passing through a filter 8 arranged in the pipe 7, the water coming from the drying tank 4 is sent using a pump 9 to an intermediate tank 10. From the intermediate tank, the water can be sent to the collecting tank i via a pipe 11 and a fitting 11 ′, using a pump 13. A bypass pipe 12 and the pump 13 can also be used, in the event of an order

  suitable for valves 38, 38a, mounted in the conduits

  tes 7 and 12, for backwashing the filter 8. A line 40 backwashing rinsing system cleaning. In parallel with the drainage in the drying tank 4, and the extraction of the drainage water via the pipe 7, evaporation takes place during drying, thanks to a heating system 15 on the wall of the tank 4. The steam thus produced is withdrawn from the drying tank 4 by a steam evacuation pipe 16 and reaches, after passing through a steam filter 17, a condenser 18. A coil 19 passing through the condenser 18 is traversed by refrigerant from the supply line 39 of the nuclear power station, for the precipitation of steam, the condensate thus formed being sent to the intermediate tank 10 via a condensate collector 21, a line 22 and the pump 9. A ventilation line 20 is

  associated with the intermediate tank 10.

  On the lower right side of the drying tank 4 is provided a sampling tube 23 for the dried resin. At this tubing, maybe

  connected a storage container 24 used to receive

  see the resin. The storage container 24 is moved

  can be cabled by a conveyor 25 along arrow 26 in the working area of a device 27 for closing the container 24. The system pressure is measured at the locations referenced P, and the temperature and the filling level are checked respectively at the locations referenced T and L. Figures 2 and 3 represent a mobile variant of the device, comprising a container 28 which receives the drying tank 4, the intermediate tank, the condenser 18, the control and

  setting 29 as well as all lines not shown

  In detail, pumps and auxiliary devices

  res necessary for operation. In Figure 2, there is only shown the connecting devices 30 for the water discharge pipe and

  31 for the resin supply line, required

  res at interfaces for connection with the collecting tank 1 of the nuclear power plant. As shown in Figure 3, the conveyor 25 is fixed

  removably on the bottom side of the container.

  This conveyor is mounted only after installation of the container 28. The conveyor 25 is for this purpose fixed on a frame 32 serving as a screen. The empty storage container 24 is brought below the delivery tubing.

  sample 23 for the dried resin, and a connection

  ment is established with a filling tube 33.

  After filling and removing this connection, the storage container 24 is brought using the conveyor 25 to a closing device 27 for closing the storage container 24. An entry area 35 accessible by a staircase 34 is separated by a screen wall 36 of the operating part of the container 28. The command and control of the device

  take place from entry area 35. The content

  neur 28 rests on feet 37 adjustable in height.

Claims (9)

  1.- Process for draining, drying and   conditioning ion exchange resins from   from a nuclear power plant and here subjected to intermediate storage in a collecting tank (1), the resins being, after drying, transferred from a drying tank (4), transferred to a   storage (24), characterized in that a disper-   Sion or suspension of water and resin, capable of being pumped, is maintained in the collecting tank (1), the dispersion is sent directly to the drying tank (4) and the water recovered from the tank.   storage is sent to the collecting tank (1).   2.- Method according to claim 1, characterized in that the water withdrawn from the drying tank (4) is sent to an intermediate tank (10) and that the water is sent from the latter to the collecting tank ( 1), to a dispersion supply line (3) and to a line (12) for backwashing a filter (8) located on the   water outlet from the drying tank.   3.- Method according to claim 1 or 2, characterized in that the water evaporated during the drying process is sent, after condensation,   in the intermediate tank (10).   4.- Method according to claim 1, characterized in that the dispersion consists   about 30% resin and about 70% water.   5.- Device for the implementation of the   method according to any of the claims   above, characterized in that the drying tank (4) capable of being heated is a tank   closed into which lead a supply line   tation in dispersion (3), capable of being connected to the collecting tank (1), that a water evacuation pipe (7) leading to the collecting tank (1), a vapor evacuation pipe ( 16) and a sampling tube (23) for the dried resin leave from the drying tank (4) and that a screw conveyor (6) is   arranged inside the drying tank (4).   6.- Device according to claim 5, characterized in that a filter (8) is disposed on the water discharge pipe (7) and that a pipe (12) for rinsing against the current of said filter is provided between the intermediate tank (10) and said filter.   7.- Device according to claim 5 or 6, characterized in that the vapor discharge pipe (16) leads to a condenser (18), which is connected to the intermediate tank (10) for sending   in the latter of the condensate formed.   8.- Device according to claim 5, characterized in that a conveyor (25) for the storage container (24) is arranged below the drying tank (4) and that the storage container (24) can be connected to the sampling tube (23) for the dried resin and be brought by said   conveyor (25) to a closure device (27).   9.- Device according to any one of   Claims 5 to 8, characterized in that the   drying tank (4), the intermediate tank (10),   the condenser (18), the corresponding connection pipes   dantes as well as the control and adjustment devices are arranged inside a container (28) which has connection pipes (30, 31) for the supply or dispersion line (3), starting from the tank collector (1) and for the water evacuation pipe (7, 11) leading to the collecting tank   (1) and that the conveyor (25) is loosely connected   visible to the container (28), below the latter.