JPH10153684A - Fuel handling device - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide MOX in a reactor building.
It is an object of the present invention to provide a fuel handling apparatus which has a relatively simple structure at the time of fuel transfer operation and which can reduce the exposure of workers without deteriorating workability. A fuel handling device (1) suspends a MOX fuel, a radiation shield (20) for shielding radiation emitted from the MOX fuel, and a fuel suspension (10) suspended by a wire (40) and a radiation shield. The unit 20 includes a base 30 suspended by a wire 50.
The radiation shielding unit 20 includes five types of shielding elements concentrically arranged in a multilayer. Each shielding element is connected to an adjacent shielding element, and is configured such that the vertical length of the radiation shielding unit 20 can be expanded and contracted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel assembly handling apparatus in a reactor building of a nuclear power plant, and more particularly to a mixed fuel assembly containing a mixed fuel of plutonium oxide and uranium oxide (hereinafter referred to as MOX fuel). ) Within a reactor building.

[0002]

2. Description of the Related Art Generally, in a boiling water reactor which is an example of a light water reactor, a uranium oxide fuel assembly (hereinafter referred to as uranium fuel) is housed in a dedicated transport container and carried into a power plant. Thereafter, the fuel cell is taken out of the transport container and subjected to a fuel inspection, temporarily stored in a storage facility such as a spent fuel pool with the channel box attached, and then loaded into the nuclear reactor.

[0003] In the case of uranium fuel, since the dose rate of radiation emitted from the fuel assembly is low, the conventional fuel handling operation described above could be handled without providing a shielding facility for protecting radiation in particular. .

[0004] Further, as prior art relating to a container for transporting spent fuel, Japanese Patent Application Laid-Open Nos. 56-26294 and 61-38 are disclosed.
No. 600 describes a transport container in which water is sealed inside for shielding neutrons emitted from spent fuel and removing decay heat generated from spent fuel. Further, Japanese Patent Application Laid-Open No. 61-38600 describes a pollution control device which covers the outside of a transport container and is provided with a seal mechanism for water in order to prevent the outer surface of the transport container from being contaminated.

[0005]

[0005] Compared with the conventional uranium fuel handling operation, the following problems are more likely to occur with MOX fuel. Since the MOX fuel has a relatively high dose rate of radiation emitted from the fuel assembly as compared with the uranium fuel, it is necessary to consider the reduction of worker exposure. For this reason, the workability is inevitably degraded, such as the limitation of work hours.

Further, Japanese Patent Application Laid-Open Nos. Sho 56-26294 and
In the transport container described in JP-A-38600, it is necessary to seal water inside, so that handling becomes complicated, and it is not suitable for handling fuel before use. Further, JP-A-61-38600
In the pollution prevention device described in the publication, the device itself does not have a function of shielding against radiation and needs to have a sealing mechanism for water, so that the structure becomes complicated.

It is an object of the present invention to provide an M
It is an object of the present invention to provide a fuel handling device which can reduce the exposure of an operator without deteriorating the workability with a relatively simple structure at the time of the OX fuel transfer operation.

[0008]

Means for Solving the Problems A first invention for achieving the above object is a first suspension for suspending a MOX fuel assembly, and a plurality of suspensions for shielding radiation emitted from the MOX fuel assembly. A radiation shielding portion in which a plurality of shielding members are concentrically configured, and a second suspension portion suspending the first suspension portion and the radiation shielding portion, wherein the second suspension portion vertically extends the first suspension portion. The plurality of shielding members are connected to each other such that the radiation shielding portion is extended in a vertical direction by being lifted upward, and the length of the radiation shielding portion in the extended state covers almost the entire length of the MOX fuel assembly. It is configured to be longer than the length.

According to a second aspect of the present invention, there is provided a fuel suspension for suspending a MOX fuel assembly, and a shield for shielding radiation emitted from the MOX fuel assembly and having a length of MOX. A radiation shielding portion having a length that is equal to or greater than a length covering substantially the entire length of the fuel assembly.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a fuel handling apparatus according to the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of a fuel handling apparatus according to the present invention, FIG. 2 is an explanatory view of a process of removing MOX fuel from a fuel transport container by the apparatus of FIG. 1, and FIG. 3 shows an example of a fuel handling operation in a reactor building. It is a flowchart.

The fuel handling operation shown in FIG. 3 shows the fuel handling from loading the fuel transport container into the reactor building to loading MOX fuel into the reactor. The operation using the fuel handling apparatus according to the present invention in the fuel handling operation of FIG. 3 includes steps 3A to 6A, steps 8A to 10A, and step 12A.
A to 14A.

Steps 3A to 6A are operations until the fuel holder containing the MOX fuel is taken out of the fuel transport container and placed on the fuel stand, and immediately before or immediately after the fuel holder is placed on the fuel stand, Is removed from the fuel holder. Steps 8A to 10A are operations for moving the MOX fuel taken out from the fuel holder from the fuel stand to the fuel inspection table and installing the same. The fuel handling device is operated immediately before or immediately after the MOX fuel is installed on the fuel inspection table. Removed from MOX fuel. Steps 12A to 14A are operations for moving the MOX fuel which has been inspected from the fuel inspection table to the channel attaching / detaching machine and installing the same.
Immediately before or immediately after the X fuel is installed in the channel detacher, the fuel handling device is removed from the MOX fuel.

Hereinafter, the configuration of the fuel handling apparatus according to the present embodiment will be described in relation to the fuel handling operation in steps 3A to 4A. The fuel handling apparatus 1 according to the present embodiment includes a fuel suspension 10 for suspending MOX fuel, a radiation shielding unit 20 for shielding radiation emitted from the MOX fuel, a fuel suspension 10 suspended by a wire 40 and radiation shielding. The unit 20 includes a base 30 suspended by a wire 50.

The radiation shielding section 20 includes five types of shielding elements 2
0a to 20e are concentrically formed in multiple layers. Each shielding element is connected to an adjacent shielding element, and as shown in FIG. 2, is configured such that the length of the radiation shielding unit 20 in the vertical direction (vertical direction) can be expanded and contracted. As a connection method between adjacent shielding elements, for example, a method of providing a plurality of fitting mechanisms of a vertically long groove and a convex portion at equal intervals in a circumferential direction can be adopted. By using such a mechanism, the structure of the fuel handling device can be made relatively simple.

Each shielding element has a substantially cylindrical or rectangular cylindrical shape, and the shielding element 20a has a fuel transport container 1 at its lower end.
05 has a protruding portion 21 which can be inserted into the fuel outlet 105a, and the shielding element 20e has an engaging portion 23 which engages with the fuel suspension 10 at the upper end thereof. The shielding element 20a further has a fuel holding mechanism 22 for preventing horizontal displacement of the fuel inside.

The shielding element is for shielding radiation such as neutrons and gamma rays emitted from the MOX fuel,
Select one that can sufficiently reduce the dose rate outside the shielding element. As the material of the shielding element, specifically, a polymer compound such as polyethylene, a metal material such as lead or stainless steel, or a combination thereof can be used.

The base 30 has a wire driving unit 31 for adjusting the length of the wire 50 in the vertical direction. When the radiation shielding unit 20 is elongated, the length of the wire 50 is increased, and the radiation shielding unit 20 is shortened. At the time of contraction, the length of the wire 50 is controlled to be reduced.

Next, a process of taking out the fuel holder 101 containing the MOX fuel from the fuel transport container 105 will be described with reference to FIG. As shown in FIG. 2A, the shielding element 20a is set in a state where the vertical length of the radiation shielding unit 20 is reduced.
Of the fuel outlet 105 of the fuel transport container 105
a, and the fuel holder 101 is lifted by the fuel hanging portion 10. For the fuel suspension 10, a gripping mechanism or the like for grasping the handle of the fuel holder 101 can be used.

In the state shown in FIG. 2A, the length of the wire 50 is extended by the wire driving unit 31 while the base 30 is lifted by the overhead crane 104 in the reactor building via the wire 104a. After the fuel suspension 10 is lifted and engaged with the shielding element 20e, as shown in FIG. 2B, the fuel suspension 10 moves upward in order from the inner shielding element 20e as the fuel suspension 10 moves upward.

The fuel holding mechanism 22 keeps holding the fuel holder 101 horizontally even while the fuel holder 101 is being lifted by the fuel hanging part 10. The fuel holding mechanism 22 has an elastic member 22a at its tip, and suppresses horizontal displacement of the fuel holder 101 by the elastic force of the elastic member 22a. FIG. 2C shows a state where the fuel holder 101 is taken out of the fuel transport container 105 in this manner. When removing the fuel handling device from the fuel holder 101, the procedure may be reversed.

As shown in FIG. 2C, the radiation shielding unit 2
In a state where 0 is extended, the length of the radiation shielding section 20 is set so as to cover the entire length of the fuel holder 101. As described above, the radiation shielding portion 20 can completely cover the fuel holder 101 except for the lower end portion. This allows
The radiation shielding unit 20 can sufficiently shield the radiation emitted from the fuel holder 101 even while the fuel holder 101 is moving.

According to the present embodiment, since the radiation shielding section 20 is configured to be expandable and contractible by the multilayer shielding elements 20a to 20e, the total length of the fuel handling apparatus can be minimized when the fuel handling apparatus is mounted on the fuel holder 101. Since the length can be shortened as much as possible, the mounting operation can be easily performed.

In this fuel handling apparatus, steps 8A to 10A
When handling the MOX fuel in steps 12A to 14A, the MOX fuel is directly suspended by the fuel suspension 10. Therefore, the fuel holding mechanism 22 is connected to the fuel holder and the MOX.
It is configured so that both fuels can be held in the horizontal direction.

According to the present embodiment, M
Even when the MOX fuel is moved inside the reactor building, such as when the OX fuel is moved, it is possible to work in an environment where the radiation emitted from the MOX fuel is sufficiently shielded, so that it is possible to reduce the exposure of the worker. Accordingly, the MOX fuel can be handled in the same manner as the uranium fuel, so that the workability does not deteriorate. Further, since a normal fitting mechanism or the like can be easily applied as a connection mechanism between the shielding elements, a relatively simple structure can be achieved.

In the present embodiment, the radiation shielding section 20 is described as having an expandable and contractible structure.
May have a fixed length. Again,
As shown in FIG. 2 (c), the radiation shielding unit 20 is
A similar effect can be obtained by providing a fuel holding mechanism 22 that engages at the upper end with 0 and holds the fuel holder or MOX fuel in the horizontal direction and has a length that covers substantially the entire length of the fuel holder or MOX fuel. be able to. In the case of the fixed type, the structure is simpler because the expansion and contraction mechanism as in the above embodiment is unnecessary. However, it becomes somewhat difficult to handle because the total length is longer.

[0026]

According to the present invention, even when the MOX fuel is moved inside the reactor building, the exposure of the worker can be reduced without deteriorating the workability with the fuel handling device having a relatively simple structure. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a fuel handling device according to the present invention.

FIG. 2 is an explanatory view of a process of taking out MOX fuel from a fuel transport container by the apparatus of FIG. 1;

FIG. 3 is a flowchart showing an example of a fuel handling operation in a reactor building.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel handling apparatus, 10 ... Fuel suspension part, 20 ... Radiation shielding part, 20a-20e ... Shielding element, 21 ... Projection part, 22
... Fuel holding mechanism, 22a ... elastic member, 23 ... engaging part, 3
0: Base, 31: Wire drive unit, 40, 50: Wire, 101: Fuel holder, 105: Fuel transport container.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Takaku 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant, Ltd. (72) Shinichi Okuda 3-1-2 Sachimachi, Hitachi-shi, Ibaraki No. 1 Inside Hitachi Engineering Co., Ltd. (72) Inventor Hiroyuki Fukuzawa 3-2-2 Samachi, Hitachi City, Ibaraki Prefecture Inside Hitachi Engineering Services Co., Ltd. (72) Koji Iida Inventor Koji Samachi, Hitachi City, Ibaraki Prefecture Hitachi Engineering Services Co., Ltd. (2-2) Inventor Yoshinari Kawada 3-1-1, Kochicho, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant

Claims (3)

[Claims] 1. A first method for suspending a MOX fuel assembly.
A hanging portion, a radiation shielding portion in which a plurality of shielding materials for shielding radiation emitted from the MOX fuel assembly are concentrically arranged in a multilayer, and a second hanging portion for suspending the first hanging portion and the radiation shielding portion. The plurality of shielding members are connected to each other such that the first hanging portion is vertically lifted by the second hanging portion so that the length of the radiation shielding portion in the vertical direction is extended. The fuel handling device according to claim 1, wherein a length of the radiation shielding portion is equal to or longer than a length covering substantially the entire length of the MOX fuel assembly. 2. A fuel suspension for suspending a MOX fuel assembly, and a length that shields radiation emitted from the MOX fuel assembly and has a length equal to or greater than a length covering substantially the entire length of the MOX fuel assembly. A fuel handling device comprising: a radiation shielding part. 3. The fuel handling apparatus according to claim 1, wherein the radiation shielding unit includes a unit for suppressing the horizontal movement of the MOX fuel assembly.