JP2000147178A - Radiation shielding structure of turbine equipment in boiling water reactor facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficient effect of radiation shield by fixing a ceiling plate of thick steel plate with a sufficient strength capable of disassembling and removing, on the upper surface of surrounding wall structure of thick steel plate stood and fixed to the operation floor so as to surround a low pressure turbine body. SOLUTION: The ceiling plate 6 is constituted to cover the upper part stood from the operation floor surface of the low pressure turbine and fixed to the surrounding wall structure 14 with a fixing jig 8. For the material, a steel plate and the like the same as that used in conventional turbine missile barrier is used. The placing location of the surrounding wall structure 14 should be a location that ensures work space in a turbine side and not interrupting other components and is fixed not to move with such a fixing jig as anchor bolts in a state independent of a turbine body. By providing the ceiling plate 6 with shielding thickness of ca. 50 to 100 mm, rational shielding becomes possible by the combination with shield structure of the building ceiling and body such as side wall. Furthermore, making the ceiling plate 6 a structure split in a plurality, optimization of a temporary placing space becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine equipment of a boiling water reactor facility, which reduces a dose equivalent rate from a low-pressure turbine main body above an operation floor and an adjacent device to the area around the turbine, and a site boundary. The present invention relates to a radiation shielding structure that reduces the effects of direct rays, skyshine rays, etc.

[0002]

2. Description of the Related Art Conventionally, around a high-pressure turbine body rising from the floor of an operating floor, two of inlet pipes 15 are located above the high-pressure turbine, and other inlet / outlet pipes 16 and peripheral equipment are all located directly below the operating floor. As shown in FIG. 6, the shield structure is connected to a high-pressure turbine under the floor, and the material is a steel plate to form a box-shaped shield body having a sufficient thickness on both side walls and ceiling. The box-shaped shield has a structure that can be divided into two parts at the center, and can be disassembled and removed with a crane when inspecting the high-pressure turbine.

Similarly, as shown in FIGS. 4 and 5, around the low-pressure turbine main body rising from the floor of the operation floor, the low-pressure turbine main body has an arc-shaped cross section along the casing except for a steam vent. The turbine missile barrier 4 composed of a cylindrical body is only directly attached to the main body, and the radiation shielding structure has an inlet pipe 17 on both sides of the main body.
The shield 3 of the low-pressure turbine peripheral device made of concrete or steel plate is provided so as to cover the low-pressure turbine peripheral device including the composite intermediate check valve 18. The radiation shield 3 may use concrete for a part of the side wall, but in general, it is a steel plate having a sufficient thickness, and the ceiling is often the same. As shown in FIG. 7, the inspection opening / closing section is generally provided with an entrance / exit 12 in the side wall section and the work is generally performed.

As described above, radiation from the equipment around the high-pressure turbine main body and around the low-pressure turbine main body is reduced to reduce radiation exposure to radiation workers. In addition, in order to reduce exposure to the general public around the power plant site, a structure having a concrete frame on the side wall and ceiling of the overhead crane operation stand as necessary is used as a measure against so-called direct lines and skyshine lines.

[0005]

In recent years, the distance between the nuclear facility and the site of the power plant has been shortened with the expansion of the plant in the existing site. Since the dose equivalent rate rises in inverse proportion to the distance to the boundary, the contribution to that is dominant, and the efficiency around the low-pressure turbine and other equipment is efficiently enhanced and strengthened, thereby increasing the dose equivalent rate around the power plant, especially the Skyshine line. It is necessary to reduce the influence from the noise.

Heretofore, shielding measures have been taken around a low-pressure turbine peripheral device including an inlet pipe and a composite intermediate check valve on both sides of a low-pressure turbine body by using a steel plate or the like which has a large shielding effect and is highly versatile. Further, the turbine missile barrier has a structure attached to the outside of the turbine main body. When trying to use the missile barrier of the turbine body as an integral part of the shielding structure as a part of shielding measures, removal of the turbine body at the time of periodic inspection, etc.
Since high accuracy is required during disassembly work, which greatly affects workability, it is difficult to set the structure thickness arbitrarily.For existing turbines, only the strength against turbine missiles is considered, and the upper limit is 16 mm in thickness. Is the actual condition, and the effect of reducing the influence from the skyshine line cannot be expected.

[0007] That is, the area around the turbine is designated as a radiation control area, but the operation of the radiation worker during operation of the reactor is a patrol for confirming abnormalities during operation of the reactor. When compared with other equipment such as pipes and high-pressure turbines, it was sufficiently lower than the reference value without shielding in the normal working area. Therefore, since patrol can be performed sufficiently away from the low-pressure turbine, there is not much demand for shielding of the low-pressure turbine body. In addition, since the conventional general public has a sufficient distance to the surrounding public, there is no need to consider the influence of the skyshine line or the like, and there is no problem even if the low-pressure turbine has no shield.

[0008] However, when the construction on a narrower site is considered in the future, the low-pressure turbine has a problem that the skyshine line particularly contributes greatly and the shielding is required.

The first object of the present invention is to enhance workability around a low-pressure turbine while securing workability,
The second purpose is to construct a new plant on a narrow site,
When expanding the existing site, the low-pressure turbine based on the shortage of the distance will increase the shielding required when the effect of the skyshine line becomes large, and the general public who has been using the building wall of the building in the vicinity will be strengthened. Shielding measures are taken by sufficiently shielding around the low-pressure turbine body to reduce the required building wall thickness of the upper floor of the operating floor,
A third object is to provide a radiation shielding structure in a turbine facility of a boiling water reactor facility, which does not impair workability during inspection of a low pressure turbine and can be stored in a narrow place by dividing a ceiling plate of a shielding body. To provide.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and in order to achieve the above object, a radiation shielding structure in a turbine facility of a boiling water reactor facility according to the present invention is provided. It has the features described in each claim of the claims.

[0011] In particular, the radiation shielding structure in the turbine equipment of the boiling water reactor facility according to the first aspect of the present invention as an independent claim is characterized in that each main body of one high-pressure turbine and a plurality of low-pressure turbines is operated on the operating floor. At the same time, on both sides of each low-pressure turbine body, low-pressure turbine peripheral equipment including the inlet piping and the composite intermediate check valve are also set up from the operating floor, and installed on both sides of each low-pressure turbine body. The high-pressure turbine body and low-pressure turbine peripheral equipment mentioned above are made of thick steel plate and rectangular in the turbine equipment of the boiling water reactor facility, which is designed to shield radiation by high-pressure turbine shields and low-pressure turbine peripheral equipment shields, respectively. A frame-shaped peripheral wall structure is erected and fixed on the floor of the operating floor so as to surround the entire low-pressure turbine body, To the top surface and is characterized by comprising also decomposed removed secure the ceiling plate having a sufficient strength as well turbine missile barrier consists steel plate.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG. 1 and 2 showing the overall outline, 1 is a high-pressure turbine shield, 2 is a low-pressure turbine main body, 3 is an inlet pipe 17 on both sides of the low-pressure turbine main body.
And a shield for low-pressure turbine peripheral equipment including a composite intermediate check valve 18; 5 is a building frame (usually having a frame up to an overhead crane operating platform); 9 is a crane; 10 is a crane operating platform; 3 shows a rail for movement. FIG. 3 shows a shielding structure 3 for peripheral equipment of a low-pressure turbine and a peripheral wall structure which is formed of a thick steel plate and formed in a rectangular frame shape, and is erected and fixed on the floor of the operating floor so as to surround the entire base of the low-pressure turbine body. FIG. 12 is an enlarged view of an intersection with a body 14, in which 12 is an entrance / exit of the composite intermediate blocking valve box in the shielding body 3 of the peripheral equipment of the low-pressure turbine when working, and 13 is a peripheral wall structure with respect to the operating floor. 14 illustrates the 14 fixtures.

Reference numeral 6 denotes a ceiling plate configured to cover an upper part of the low-pressure turbine 2 raised from the operating floor, and is fixed on the peripheral wall structure 14 by a fixture 8, and is made of a conventional turbine missile. The same steel plate used for the barrier is used. As shown in FIG. 3, the installation position of the peripheral wall structure 14 is such that the work space on the turbine side is secured as shown in FIG. Install so that it does not interfere with other devices. As for the installation method, it is necessary to select an appropriate method based on the arrangement of the equipment, but as shown in the example of FIG. Secure so that it does not move.

By providing the ceiling plate 6 with a shielding thickness of about 50 to 100 mm (depending on the conditions of the plant), it is possible to perform rational shielding in combination with the shielding structure of the building ceiling and side walls. .

As a result, the radiation dose to radiation workers and the general public around the power plant can be significantly reduced. Further, by adjusting the thickness of the ceiling plate 6, it is possible to reduce the structural thickness of the building such as the building ceiling and side walls, which may be restricted by the terrain. In addition, it is possible to arrange the plant closer to the site boundary, and it is also possible to perform a layout plan that effectively uses the site (addition to an existing site or new installation in a narrower area than before). At the same time, the same material is used for the conventional turbine missile barrier (16 mm thick).
Since it has a thickness of about 6 times, it is possible to function as a turbine missile barrier to protect the ceiling panel 6 from physical damage caused by the turbine missile to the outside.

Furthermore, since the ceiling plate 6 is divided into a plurality of structures, the temporary storage space can be optimized, so that the appropriately divided ceiling portion can be stored in the extra space in the conventional building shape. It becomes possible. The ceiling plate 6 of the present embodiment
Is divided into rectangular plates which are easy to be lifted by a crane 9 and have a size suitable for storage. It has a hook and a fixture such as 8 to prevent it from being displaced by the impact of the turbine missile.

[0017]

According to the first aspect of the present invention, since a sufficient radiation shielding effect in the low-pressure turbine body is achieved, it is not necessary to remove all the shielding members at the time of inspection, so that the workability is good. Further, it is also effective as a protection plate against turbine missiles.

According to the second aspect of the present invention, it is easier than the concrete shielding of the building, the structure of the upper floor of the operation floor is reduced, and as a result, the frame structure of the whole building can be reduced.

According to the third aspect of the present invention, the space for temporarily placing the shield in the building design can be small.
Space saving of the building can be achieved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an arrangement in a case of installing a turbine shielding structure around a low-pressure turbine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a crossing point between a shield 3 around a low-pressure turbine inlet pipe and a turbine shield structure 6 in FIG. 1;

FIG. 4 is a plan view of a conventional shield installation around a turbine.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a sectional view of a high-pressure turbine shield.

FIG. 7 is a sectional view of a low-pressure turbine peripheral equipment shield.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... High-pressure turbine shield 2 ... Low-pressure turbine main body 3 ... Low-pressure turbine peripheral equipment shield 4 ... Turbine missile barrier 5 ... Building frame 6 ... Ceiling plate 7 ... Crane hanging hook 8 ... Fixture 9 ... Crane 10 ... Crane Operation stand 11 ... Cranes for moving the operation stand 12 ... Entry / exit 13 ... Fixer 14 ... Surrounding wall structure 15 ... Inlet piping 16 ... Entrance piping 17 ... Inlet piping 18 ... Composite intermediate block valve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshihisa Tsukiyama 3-2-1 Sachimachi, Hitachi City, Ibaraki Prefecture Within Hitachi Engineering Co., Ltd. (72) Inventor Hideo Nakano 3-2-2 Sachimachi, Hitachi City, Ibaraki Prefecture No. 1 Hitachi Engineering Co., Ltd. (72) Inventor Kenichi Wakasugi 3-2-1 Sachimachi, Hitachi City, Ibaraki Prefecture Inside Hitachi Engineering Co., Ltd.

Claims (3)

[Claims] 1. A main body of one high-pressure turbine and a plurality of low-pressure turbines are arranged in series by standing up from an operation floor, and an inlet pipe and a composite intermediate member are provided on both sides of each low-pressure turbine main body. The low-pressure turbine peripheral equipment including the check valve is also set up from the floor of the operating floor, and the raised high-pressure turbine body and low-pressure turbine peripheral equipment are radiated by the high-pressure turbine shield and the low-pressure turbine peripheral equipment shield, respectively. In a turbine facility of a boiling water reactor facility configured to shield an operation floor, a surrounding wall structure formed of a thick steel plate and formed in a rectangular frame shape surrounds the entire base of the low-pressure turbine main body. It can be disassembled and removed from the ceiling wall, which is also made of thick steel plate and has sufficient strength as a turbine missile barrier. Radiation shielding structure in a turbine equipment of the boiling water reactor facilities which characterized by being fixed to. 2. The steel plate of the peripheral wall structure and the ceiling plate,
The thickness is 50 to 1 depending on the conditions of the reactor facility.
The radiation shielding structure in the turbine equipment of the boiling water reactor facility according to claim 1, wherein the radiation shielding structure is 00 mm. 3. The radiation shielding structure in a turbine equipment of a boiling water reactor facility according to claim 1, wherein the ceiling plate is divided into a plurality of sheets.