JPS606800Y2 - Adhering sodium removal equipment - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a device for removing sodium adhering to equipment and the like.

Fuel assemblies used in sodium-cooled fast breeder reactors,
Sodium adheres to various components and equipment, and at the same time, nuclear fission products also adhere to them.

Therefore, it is necessary to remove adhering sodium during maintenance, storage, etc. of these devices, and conventionally, reactive cleaning such as steam cleaning or alcohol cleaning, or non-reactive cleaning such as oil cleaning or molten metal cleaning is used.

However, these conventional methods all remove sodium by bringing various fluids into contact with the equipment surface, so they have the disadvantage that it is difficult to sufficiently remove sodium adhering to the details, and waste liquid must be treated. There is also the problem.

One way to solve these drawbacks was to circulate high-temperature inert gas to evaporate the sodium adhering to the object to be removed, and then use a paper trap to condense and remove the sodium.

However, in the case of this device, in addition to the container containing the object to be removed, additional equipment such as a pump for forced circulation of inert gas, a gas heater, and a paper trap are required, so the configuration is complicated. There was also the problem of increasing the size of the facility.

This invention was made based on the above-mentioned circumstances, and its purpose is to provide a device for removing adhering sodium that can effectively remove adhering sodium with a simple configuration.

This invention will be explained below based on an illustrated embodiment.

In the figure, reference numeral 1 denotes an outer container as an airtight container, and the outer container 1 consists of a bottomed container-shaped main body 1a with an open top, and a hollow lid 1b that closes the upper opening of the main body 1a. The lid portion 1b is airtightly fixed to the main body portion 1a by a fixture 2.

A sodium receiver member 3 is provided between the main body portion 1a and the lid portion 1b, and forms a gutter-shaped sodium receiver continuous in the circumferential direction on the lower inner periphery of the lid portion 1b.

This sodium receiver member 3 is a lid part 1 as described later.
This is to store the sodium that condenses and flows down on the inner surface of the lid part 1b, and is fastened together to the lid part 1b using the fixture 2 mentioned above.

Furthermore, radiation fins 4 are provided on the outer surface of the lid portion 1b.

Further, the main body portion 1a is provided with a supply/exhaust port 5, and an inert gas supply source and an exhaust pump (not shown) are connected to the supply/exhaust port 5 via an on-off valve 6.

Further, a heating wire heater 7 is provided at the lower part of the main body portion 1a.

The outer container 1 has a built-in heating cylinder 8 for accommodating the object A to be removed of sodium.

This heating cylinder 8 has a double cylindrical shape with a vacuum insulation space 9 inside, has an exhaust port 8a at the top, an intake port 8b at the bottom, and is a cylindrical support equipped with a ventilation port 10a. It is vertically supported by member 10.

A heating wire heater 11 is attached to the vacuum insulation space 9 of the heating cylinder 8 to heat the inner surface.

The adhering sodium removal device configured as described above accommodates the objects A to be removed from sodium, such as fuel assemblies used in fast breeder reactors, pumps, valves, pipes, etc., in the heating cylinder 8, and opens the on-off valve 6. Then, the outer container 1 is filled with an inert gas such as argon.

Then, the heater 11 of the heating cylinder is energized to heat the object A to be removed of sodium to a temperature at which the IJum evaporates, and the heater 7 of the outer container is also made to generate heat, thereby warming the outer container 1 from the lower side.

The gas heated by these heaters 7.11 causes natural convection as shown by the arrows, and the heating cylinder 8 is heated to a high temperature.
The inside rises due to the so-called chimney effect.

Since the sodium removal target A is heated in the heating cylinder 8 in this way, the adhering sodium A The steam collides with the inner surface of the lid part 1b.

Since this lid part 1b is cooled by the radiation fins 4, the sodium vapor condenses and flows down along the inner surface of the lid part 1b, and the sodium receiver accumulates in the member 3.

The member 3 is attached to the lid part 1b by the fixture 2.
Once the lid portion 1b is removed, the sodium receiver member 3 can be easily removed and the condensed sodium can be easily recovered.

Further, since the above-mentioned receiver can prevent the sodium from flowing down by the member 3, it is possible to prevent the condensed sodium from accumulating at the bottom of the outer container 1 and re-evaporating.

Further, according to this embodiment, since the heat insulating space 9 is provided in the heating cylinder 8, the heat generated by the heater 11 can be prevented from escaping to the outer surface of the heating cylinder, and the object A to be removed of sodium can be effectively heated. It is something.

It is also possible to exhaust the gas inside the outer container 1 through the supply/exhaust port 5, and by lowering the pressure inside the outer container 1 in this way, the evaporation of the adhering sodium can be promoted.
Sodium removal can be performed more efficiently.

It goes without saying that the specific configuration of the heating cylinder or the outer container, such as the shape and size, can be modified in various ways according to the shape and size of the object to be accommodated for sodium removal.

Furthermore, the object to be removed from sodium is not limited to fast breeder reactor equipment, but can be similarly applied to any equipment that handles sodium.

As explained above, in this device, a heating cylinder with an exhaust port at the top and an intake port at the bottom is housed in an outer container filled with inert gas, and the object to be removed of sodium is heated inside the heating cylinder. This heating method evaporates the adhering sodium on the surface and condenses and collects it, so compared to cleaning using fluids such as steam cleaning or alcohol cleaning, sodium is removed from the details of the equipment. can be reliably removed, and sodium can be safely removed without producing reaction products.

In addition, the evaporation of sodium is promoted by the upward flow inside the heating cylinder caused by convection, and this upward flow can automatically lead the sodium vapor to the upper cooling means, so the fluid is forced using a pump etc. It has a simpler configuration and can remove sodium more efficiently than those that circulate.
Furthermore, since there are no moving parts, it is highly durable and easy to operate, which has great practical effects.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of a sodium removal device showing an embodiment of this invention. 1... Outer container, 4... Radiation fin,
8...Heating cylinder, 8a...Exhaust port, 8b
... Intake port, 9 ... Heat insulation space, 11
... Heat-generating wire heater, object to be removed from lithium. A...Nato

Claims (1)

[Scope of utility model registration request] an airtight container consisting of a main body in the shape of a bottomed container with an opening at the top and an inert gas sealed inside, and a hollow lid having radiation fins on the outer surface and closing the upper opening of the main body;
A cylindrical support member installed at the bottom of the airtight container and having a ventilation hole on the side surface; a double cylindrical heating cylinder placed on the support member and having an annular vacuum insulation space formed therein; A sodium removal object housed in the heating cylinder and having sodium attached to its surface, a heater provided in the lower part of the sealed container and the vacuum insulation space of the heating cylinder to heat an inert gas, and a main body in the sealed container. 1. A device for removing adhering sodium, comprising: a sodium receiver member provided between the lid part and the lid part and forming a gutter-shaped sodium receptor continuous in the circumferential direction on the inner periphery of the lower part of the lid part.