阅读说明：本技术 核电厂 (Nuclear power plant ) 是由 S.J.贝克特 于 2019-07-04 设计创作，主要内容包括：核电厂(10)包括：核反应堆(12),核反应堆包括反应堆燃料元件(14),围绕核反应堆(12)的反应堆壳(16)和围绕反应堆壳(16)的主屏蔽层(18)。反应堆燃料元件(14)布置在第一高度(H1)与高于第一高度(H1)的第二高度(H2)之间。主屏蔽层(18)包括基部部分(30)、中间部分(32)和顶部部分(34)。基部部分(30)具有在第一高度(H1)以下的上部高度(H3),并且基部部分(30)包括混凝土。顶部部分(34)具有在第二高度(H2)以上的下部高度(H4),并且顶部部分(34)包括混凝土。中间部分(32)垂直布置在主屏蔽层(18)的基部部分(30)与顶部部分(34)之间。中间部分(32)包括至少一个支撑结构(36,36A,36B,36C)和含有钨或硼的基体材料(32A,32B),并且至少一个支撑结构(36,36A,36B,36C)在主屏蔽层(18)的顶部部分(34)与底部部分(30)之间延伸。(A nuclear power plant (10) comprises: a nuclear reactor (12) includes a reactor fuel element (14), a reactor shell (16) surrounding the nuclear reactor (12), and a primary shield (18) surrounding the reactor shell (16). The reactor fuel element (14) is disposed between a first height (H1) and a second height (H2) that is higher than the first height (H1). The primary shield (18) includes a base portion (30), a middle portion (32), and a top portion (34). The base portion (30) has an upper height (H3) below the first height (H1), and the base portion (30) comprises concrete. The top portion (34) has a lower height (H4) above the second height (H2), and the top portion (34) comprises concrete. The intermediate portion (32) is vertically disposed between the base portion (30) and the top portion (34) of the primary shield (18). The intermediate portion (32) includes at least one support structure (36, 36A,36B, 36C) and a base material (32A, 32B) comprising tungsten or boron, and the at least one support structure (36, 36A,36B, 36C) extends between the top portion (34) and the bottom portion (30) of the primary shield layer (18).)

1. A nuclear power plant, comprising: a nuclear reactor including reactor fuel elements, a reactor shell surrounding the nuclear reactor, and a main shield surrounding the reactor shell, the reactor fuel elements being arranged between a first elevation and a second elevation higher than the first elevation, the main shield forming at least a ring around the reactor shell, the main shield including a base portion, an intermediate portion, and a top portion, each of the base portion, the intermediate portion, and the top portion extending continuously circumferentially around the reactor shell, the base portion of the main shield having an upper elevation at or below the first elevation and the base portion including concrete, the top portion of the main shield having a lower elevation at or above the second elevation and the top portion including concrete, the intermediate portion of the main shield being arranged vertically between the base portion and the top portion, the intermediate portion includes at least one support structure and a base material comprising tungsten, boron, silver, indium, hafnium, or cadmium, and the at least one support structure extends between a top portion and a bottom portion of the primary shield layer.

2. The nuclear power plant as recited in claim 1 wherein the at least one support structure includes an inner concrete member and an outer concrete member, a single layer of a matrix material containing tungsten or boron disposed between the inner concrete member and the outer concrete member.

3. A nuclear power plant as claimed in claim 1, wherein the at least one support structure comprises an inner steel member and an outer steel member, a single layer of matrix material containing tungsten or boron being disposed between the inner and outer steel members.

4. The nuclear power plant as recited in claim 1 wherein the at least one support member includes an inner steel reinforced concrete member and an outer steel reinforced concrete member, a single layer of a matrix material containing tungsten or boron disposed between the inner steel reinforced concrete member and the outer steel reinforced concrete member.

5. The nuclear power plant as recited in claim 1 wherein the at least one support member includes an inner concrete member, an intermediate concrete member, and an outer concrete member, a first layer of a matrix material containing tungsten or boron is disposed between the inner concrete member and the intermediate concrete member, and a second layer of a matrix material containing tungsten or boron is disposed between the intermediate concrete member and the outer concrete member.

6. A nuclear power plant as claimed in claim 1, wherein the at least one support member comprises an inner steel member, an intermediate steel member and an outer steel member, a first layer of tungsten or boron containing matrix material being disposed between the inner steel member and the intermediate steel member and a second layer of tungsten or boron containing matrix material being disposed between the intermediate steel member and the outer steel member.

7. The nuclear power plant as recited in claim 1 wherein the at least one support member includes an inner steel reinforced concrete member, an intermediate steel reinforced concrete member, and an outer steel reinforced concrete member, a first layer of a matrix material containing tungsten or boron is disposed between the inner steel reinforced concrete member and the intermediate steel reinforced concrete member, and a second layer of a matrix material containing tungsten or boron is disposed between the intermediate steel reinforced concrete member and the outer steel reinforced concrete member.

8. The nuclear power plant of any one of claims 1 to 7, wherein the matrix material comprises a polymeric material.

9. The nuclear power plant as recited in claim 8 wherein the polymeric material includes polypropylene or polyethylene.

10. The nuclear power plant of any one of claims 1 to 7, wherein tungsten or boron is distributed throughout the matrix material as a powder or as particles.

11. The nuclear power plant of any one of claims 1 to 7, wherein the primary shield includes an inner steel liner and an outer steel liner, the base portion, the intermediate portion and the top portion being sandwiched between the inner steel liner and the outer steel liner.

12. The nuclear power plant of any one of claims 1 to 7, wherein the intermediate portion has a radially inner surface and a radially outer surface, the intermediate portion having the same vertical height at the radially outer surface as the radially inner surface.

13. The nuclear power plant of any one of claims 1 to 7, wherein the intermediate portion has a radially inner surface and a radially outer surface, the intermediate portion having a greater vertical height at the radially outer surface than the radially inner surface.

14. The nuclear power plant of any one of claims 1 to 7, wherein the intermediate portion has a radially inner surface and a radially outer surface, the intermediate portion having a greater vertical height at the radially inner surface than the radially outer surface.

15. The nuclear power plant of any one of claims 1 to 7 wherein a further wall surrounds the primary shield, a containment surrounds the further wall, and a building wall surrounds the containment.

16. The nuclear power plant of any one of claims 1 to 7 wherein the nuclear reactor is a pressurized water reactor or a boiling water reactor.

17. The nuclear power plant of any one of claims 1 to 7 wherein the nuclear reactors are small modular reactors.

18. The nuclear power plant as recited in claim 17 wherein the small modular nuclear reactor produces up to 500 MWe.

19. The nuclear power plant as recited in claim 18 wherein the small modular nuclear reactor produces 220 to 440 MWe.

Technical Field

The present disclosure relates to nuclear power plants.

Background

The nuclear power plant comprises: a nuclear reactor including reactor fuel elements, a reactor shell surrounding the reactor fuel elements, a primary shield surrounding the reactor shell, a remote wall surrounding the primary shield, a containment vessel surrounding the remote wall, and a building wall surrounding the containment vessel. The reactor shell typically comprises steel having a thickness of 4 to 8 inches, 10 to 20 cm. The primary shield typically comprises a 4 foot, 1.22 m lead (leaded) concrete wall with inner and outer steel linings each having a thickness of 1.5 inches, 3.8 mm. Remote walls typically comprise reinforced concrete having a thickness of 5 feet, 1.52 m. The containment vessel typically comprises steel having a thickness of 1.5 inches, 3.8 mm, and the building wall typically comprises reinforced concrete having a thickness of 3 feet, 0.91 m.

The primary shield, sometimes referred to as a biological shield, is arranged to prevent neutron flux from exiting the reactor to the ambient environment when the reactor is operating, and to block gamma rays from the irradiation pressure/reactor shell when the reactor is shut down. It is designed to prevent radiation dose to the human body when the reactor is shut down for inspection and also to prevent irradiation of nearby structural materials and other components of the nuclear power plant when the reactor is operating.

The primary shield layer consists primarily of concrete, but concrete does not provide a high level of neutron shielding, and therefore the primary shield layer requires a relatively large amount of concrete, and therefore the concrete must be relatively thick. An advantage of concrete is that concrete is relatively cheap. The primary shield is not optimized to maximize the extent of neutron shielding, but rather to minimize the amount of material used for neutron shielding.

Accordingly, the present disclosure seeks to provide a nuclear reactor with a primary shield that reduces or overcomes the above-mentioned problems.

Disclosure of Invention

According to a first aspect, there is provided a nuclear power plant comprising: a nuclear reactor comprising a reactor fuel element, a reactor shell surrounding the nuclear reactor and a primary shield surrounding the reactor shell, the reactor fuel element being arranged between a first height and a second height higher than the first height, the primary shield forming at least a ring around the reactor shell, the primary shield comprising a base portion, an intermediate portion and a top portion, each extending continuously circumferentially around the reactor shell, the base portion of the primary shield having an upper height at or below the first height and the base portion comprising concrete, the top portion of the primary shield having a lower height at or above the second height and the top portion comprising concrete, the intermediate portion of the primary shield being arranged vertically between the base portion and the top portion, the intermediate portion comprising at least one support structure and comprising tungsten, A base material of boron, silver, indium, hafnium, or cadmium, and at least one support structure extending between a top portion and a bottom portion of the primary shield layer.

The at least one support structure may comprise an inner concrete member and an outer concrete member, the single layer of matrix material comprising tungsten or boron being arranged between the inner concrete member and the outer concrete member.

The at least one support structure may include an inner steel member and an outer steel member with a single layer of a tungsten or boron containing matrix material disposed therebetween.

The at least one support member may comprise an inner steel reinforced concrete member and an outer steel reinforced concrete member, the single layer of matrix material comprising tungsten or boron being arranged between the inner steel reinforced concrete member and the outer steel reinforced concrete member.

The at least one support member may comprise an inner concrete member, an intermediate concrete member and an outer concrete member, the first layer of matrix material comprising tungsten or boron being arranged between the inner concrete member and the intermediate concrete member and the second layer of matrix material comprising tungsten or boron being arranged between the intermediate concrete member and the outer concrete member.

The at least one support member may include an inner steel member, an intermediate steel member, and an outer steel member, with a first layer of a tungsten or boron containing matrix material disposed between the inner steel member and the intermediate steel member, and a second layer of a tungsten or boron containing matrix material disposed between the intermediate steel member and the outer steel member.

The at least one support member may include an inner steel reinforced concrete member, an intermediate steel reinforced concrete member, and an outer steel reinforced concrete member, the first layer of matrix material containing tungsten or boron being disposed between the inner steel reinforced concrete member and the intermediate steel reinforced concrete member, and the second layer of matrix material containing tungsten or boron being disposed between the intermediate steel reinforced concrete member and the outer steel reinforced concrete member.

The matrix material may comprise a polymeric material. The polymeric material may comprise polypropylene or polyethylene. Tungsten or boron may be distributed throughout a matrix material, e.g., a polymer material, as a powder or as particles. The matrix material may contain both tungsten and boron. The matrix material may contain tungsten carbide, boron nitride or boron carbonitride. The matrix material may contain tungsten and/or boron as other suitable compounds.

The primary shield may include an inner steel liner and an outer steel liner, the base portion, the middle portion, and the top portion being sandwiched between the inner steel liner and the outer steel liner.

The intermediate portion may have a radially inner surface and a radially outer surface, the intermediate portion having the same vertical height at the radially outer surface as the radially inner surface.

The intermediate portion may have a radially inner surface and a radially outer surface, the intermediate portion having a greater vertical height at the radially outer surface than the radially inner surface.

The intermediate portion may have a radially inner surface and a radially outer surface, the intermediate portion having a greater vertical height at the radially inner surface than at the radially outer surface.

The remote wall may surround the primary shield, the containment vessel surrounds the remote wall, and the building wall surrounds the containment vessel.

The nuclear reactor may be a pressurized water reactor or a boiling water reactor.

The nuclear reactor may be a small modular reactor.

Small modular nuclear reactors can produce up to 500 MWe.

Small modular nuclear reactors can produce 220 to 440 MWe.

Those skilled in the art will appreciate that features described in relation to any one of the above aspects may be applied to any other aspect, mutatis mutandis, unless mutually exclusive therein. Moreover, any feature described herein may be applied to any aspect and/or in combination with any other feature described herein, unless mutually exclusive therein.

Drawings

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional side view of a nuclear power plant according to the present disclosure.

FIG. 2 is an enlarged cross-sectional side view of a portion of the nuclear power plant shown in FIG. 1.

FIG. 3 is an alternative enlarged cross-sectional side view of a portion of the nuclear power plant shown in FIG. 1.

FIG. 4 is another alternative enlarged cross-sectional side view of a portion of the nuclear power plant shown in FIG. 1.

FIG. 5 is a further alternate enlarged cross-sectional side view of a portion of the nuclear power plant shown in FIG. 1.

Detailed Description

FIG. 1 illustrates a nuclear power plant 10 including a nuclear reactor 12, a reactor shell 16 surrounding the nuclear reactor 12, and a primary shield 18 surrounding the reactor shell 16. The nuclear reactor 12 includes a reactor fuel element 14. Remote wall 20 surrounds primary shield 18, containment 22 surrounds remote wall 20, and building wall 24 surrounds containment 22. The primary shield 18 forms a ring at least around the reactor shell 16. The reactor shell 16 comprises a main portion 17 and a cover 19. The nuclear power plant 10 also includes a primary circuit 25, a heat exchanger 26, a secondary circuit 27, a turbine 28 and a generator 29. The primary fluid in the primary loop 25 is heated by the nuclear reactor 12. The primary fluid flows from the nuclear reactor 12 through a conduit 25A to a heat exchanger 26 where it heats the secondary fluid in a secondary loop 27. The primary fluid in the primary loop 25 flows from the heat exchanger 26 through a conduit 25B back to the nuclear reactor 12. The heated secondary fluid in the secondary loop 27 flows through a conduit 27A to the turbine 28 and drives the turbine 28, which in turn drives a generator 29 to produce electricity. For example, the secondary fluid is water, the heated secondary fluid is steam, and the turbine 28 is a steam turbine 28. Alternatively, the turbine 28 may provide drive for other purposes. The nuclear reactor 12 may be a Boiling Water Reactor (BWR) or a Pressurized Water Reactor (PWR). If the nuclear power plant 10 includes a pressurized water reactor, then a pressurizer may be present. The nuclear reactor 12 may be a Small Modular Reactor (SMR), for example, for producing up to 500 MWe, for example, 220 to 440 MWe.

Fig. 2 shows a first arrangement of the main shield layer 18 in more detail. The reactor fuel elements 14 are disposed between a first height H1 and a second height H2 that is higher than the first height H1. The first and second heights H1 and H2 are measured relative to the base level or base height B. The primary shield 18 includes a base portion 30, a middle portion 32, and a top portion 34. The base portion 30, the intermediate portion 32, and the top portion 34 each extend circumferentially continuously around the reactor shell 16. The base portion 30 of the main shield 18 has an upper height H3 disposed below the first height H1. The base portion 30 comprises concrete. The top portion 34 of the main shield 18 has a lower height H4 disposed above the second height H2. Heights H3 and H4 are also measured relative to base level or base height B. The top portion 34 comprises concrete. The middle portion 32 of the primary shield 18 is vertically disposed between the base portion 30 and the top portion 34. The intermediate portion 32 includes a base material comprising tungsten or boron and at least one support structure 36. At least one support structure 36 extends between the top portion 34 and the bottom portion 30 of the primary shield 18. At least one support structure 36 supports the middle portion 32 and the top portion 34 of the primary shield 18. The main shield layer 18 has a thickness T.

In this example, the at least one support structure 36 includes a radially inner support structure 36A, a radially intermediate support structure 36B, and a radially outer support structure 36C. A first layer 32A of a matrix material containing tungsten or boron is disposed between the radially inner support structure 36A and the radially intermediate support structure 36B, and a second layer 32B of a matrix material containing tungsten or boron is disposed between the radially intermediate support structure 36B and the radially outer support structure 36C. The radially inner support structure 36A, the radially intermediate support structure 36B and the radially outer support structure 36C comprise concrete and/or steel. The radially inner support structure 36A, the radially intermediate support structure 36B, and the radially outer support structure 36C may each comprise concrete, steel reinforced concrete, or concrete with steel lining. The matrix material may comprise a polymeric material. The polymeric material may comprise polypropylene or polyethylene. The polymeric material may also include any polymer that is injection moldable and has both their thermal properties and their neutron absorbing properties. Tungsten or boron may be distributed throughout a matrix material, e.g., a polymer material, as a powder or as particles. The matrix material may contain both tungsten and boron. The matrix material may contain tungsten and/or boron, such as tungsten carbide, boron nitride, boron carbonitride or such as other suitable compounds, as long as they do not adversely affect the material properties of the intermediate portion 32 of the primary shield layer 18 in such a way as to make it impossible to manufacture the first layer 32A and/or the second layer 32B.

It should be noted that intermediate portion 32 has a radially inner surface and a radially outer surface, intermediate portion 32 having a vertical height L1 at the radially inner surface of intermediate portion 32 and a vertical height L2 at the radially outer surface, and that the vertical height L2 at the radially outer surface is greater than the vertical height L1 at the radially inner surface. It should be particularly noted that the second layer 32B of the base material containing tungsten or boron has a larger vertical height than the first layer 32A of the base material containing tungsten or boron. Thus, the intermediate portion 32 is contoured. It should also be noted that vertical height L1= height H4-height H3.

In a first example, the radially inner support structure 36A comprises an inner concrete member, the radially intermediate support structure 36B comprises an intermediate concrete member, the radially outer support structure 36C comprises an outer concrete member, the first layer 32A of a polymer matrix containing tungsten or boron is sandwiched between the inner concrete member and the intermediate concrete member, and the second layer 32B of a polymer matrix containing tungsten or boron is sandwiched between the intermediate concrete member and the outer concrete member. Further, an inner steel liner may be disposed on the inner surface of the primary shield layer 18, and an outer steel liner may be disposed on the outer surface of the primary shield layer 18.

In a second example, the radially inner support structure 36A comprises an inner steel reinforced concrete member, the radially intermediate support structure 36B comprises an intermediate steel reinforced concrete member, the radially outer support structure 36C comprises an outer steel reinforced concrete member, the first layer 32A of tungsten or boron containing polymer matrix is sandwiched between the inner steel reinforced concrete member and the intermediate steel reinforced concrete member, and the second layer 32B of tungsten or boron containing polymer matrix is sandwiched between the intermediate steel reinforced concrete member and the outer steel reinforced concrete member. Further, an inner steel liner may be disposed on the inner surface of the primary shield layer 18, and an outer steel liner may be disposed on the outer surface of the primary shield layer 18.

Thus, the primary shield 18 includes a matrix material containing tungsten or boron to shield around the region of the reactor shell 16 where the neutron flux is highest. The structural requirements for the primary shield 18 in this region are provided by concrete and/or steel support structures 36A,36B and 36C, while the first and second layers 32A and 32B of matrix material containing tungsten or boron are used to make up the majority of the thickness of the primary shield 18 in this region and to prevent neutron flux from exiting the nuclear reactor 12 to the ambient environment when the nuclear reactor 12 is operating and to block gamma rays from the irradiation pressure/reactor shell 16 when the nuclear reactor 12 is shut down. The first and second layers 32A and 32B of the matrix material comprising tungsten or boron also prevent radiation dose to the human body when the nuclear reactor 12 is shut down for inspection, and also prevent irradiation of nearby structural materials and other components of the nuclear power plant 10 when the nuclear reactor 12 is operating.

The main shield layer 18 reduces the thickness of the main shield layer 18 by up to 50% by virtue of the superior shielding performance of tungsten in the matrix material compared to concrete. For example, the primary shield 18 has a thickness T of 2 to 3 feet. This provides a significant reduction in the space occupied by the primary shield 18, allowing components surrounding the nuclear reactor 12, e.g., the heat exchanger 26, pressurizer, to be placed closer to the nuclear reactor 12. This reduces the length of pipeline work, reduces the likelihood of pipeline breakage, and reduces the amount of radioactive waste to be disposed of at the end of the operational life of the nuclear reactor 12 and the nuclear power plant 10. The primary shield 18 uses the advantages of the superior structural properties of the concrete and/or steel support structures 32A,32B and 32C to protect the first and second layers 32A and 32B of the matrix material containing tungsten or boron in the event of an accident. It also reduces the amount of tungsten or boron required, thereby significantly reducing cost while retaining the shielding benefits of the tungsten or boron containing matrix material. The contoured mid-portion 32 of the primary shield 18 matches the maximum neutron flux emitted from the nuclear reactor 12 and is designed such that, for example, a minimum amount of tungsten or boron-based matrix material is used in the first and second layers 32A and 32B.

Fig. 3 shows a second arrangement of the main shield layer 18A in more detail. The second arrangement of the main shield layer 18A is substantially the same as the main shield layer 18 shown in fig. 2, and like parts are denoted by like symbols. The primary shield 18A differs in that the at least one support structure 36 includes only a radially inner support structure 36A and a radially outer support structure 36C. A single layer 32C of a matrix material comprising tungsten or boron is disposed between the radially inner support structure 36A and the radially outer support structure 36C. The radially inner support structure 36A and the radially outer support structure 36C comprise concrete and/or steel. Radially inner support structure 36A and radially outer support structure 36C may each comprise concrete, steel reinforced concrete, or concrete with a steel lining. The matrix material may comprise a polymeric material. The polymeric material may comprise polypropylene or polyethylene. The polymeric material may also include any polymer that is injection moldable and has both their thermal properties and their neutron absorbing properties. Tungsten or boron may be distributed throughout a matrix material, e.g., a polymer material, as a powder or as particles. The matrix material may contain both tungsten and boron. The matrix material may contain tungsten and/or boron, such as tungsten carbide, boron nitride, boron carbonitride or such as other suitable compounds, as long as they do not in this way negatively affect the material properties of the intermediate portion 32 of the main shield layer 18, so as to make it impossible to manufacture a single layer 32C.

Also, it should be noted that intermediate portion 32 has a radially inner surface and a radially outer surface, intermediate portion 32 having a vertical height L1 at the radially inner surface of intermediate portion 32 and a vertical height L2 at the radially outer surface, and that the vertical height L2 at the radially outer surface is greater than the vertical height L1 at the radially inner surface. It should be particularly noted that the single layer 32C of matrix material containing tungsten or boron has a greater vertical height nearer the radially outer surface than nearer the radially inner surface. Thus, the intermediate portion 32 is along a contour. It should also be noted that vertical height L1= height H4-height H3.

Fig. 4 shows a third arrangement of the main shield layer 18B in more detail. The third arrangement of the main shield layer 18B is substantially the same as the main shield layer 18 shown in fig. 2, and like parts are denoted by like symbols. The main shield 18B differs in that the intermediate portion 32 has a radially inner surface and a radially outer surface, the intermediate portion 32 has a vertical height L1 at the radially inner surface of the intermediate portion 32 and a vertical height L2 at the radially outer surface, and the vertical height L2 at the radially outer surface is the same as the vertical height L1 at the radially inner surface. It should also be noted that vertical height L1= vertical height L2= height H4-height H3. It should be particularly noted that the first layer 32A of the base material containing tungsten or boron has the same vertical height as the second layer 32B of the base material containing tungsten or boron. Alternatively, in arrangements without a radially intermediate support structure, a single layer of matrix material containing tungsten or boron may be disposed between the radially inner and outer support structures.

Fig. 5 shows a fourth arrangement of the main shield layer 18C in more detail. The fourth arrangement of the main shield layer 18C is substantially the same as the main shield layer 18 shown in fig. 2, and like parts are denoted by like symbols. The main shield 18C differs in that the intermediate portion 32 has a radially inner surface and a radially outer surface, the intermediate portion 32 has a vertical height L1 at the radially inner surface of the intermediate portion 32 and a vertical height L2 at the radially outer surface, and the vertical height L1 at the radially inner surface is greater than the vertical height L2 at the radially outer surface. It should also be noted that vertical height L2= height H4-height H3.

It should be particularly noted that the first layer 32A of the base material containing tungsten or boron has a greater vertical height than the second layer 32B of the base material containing tungsten or boron. Thus, the intermediate portion 32 is along a contour. Alternatively, in arrangements without a radially intermediate support structure, a single layer of matrix material containing tungsten or boron may be disposed between the radially inner and outer support structures.

A first layer of a base material comprising tungsten or boron may be disposed between the inner steel member and the intermediate steel member, and a second layer of a base material comprising tungsten or boron may be disposed between the intermediate steel member and the outer steel member. A first layer of a matrix material containing tungsten or boron may be disposed between the inner concrete member and the intermediate concrete member, and a second layer of a matrix material containing tungsten or boron may be disposed between the intermediate concrete member and the outer concrete member. A first layer of a matrix material containing tungsten or boron may be arranged between the inner steel reinforced concrete member and the intermediate steel reinforced concrete member, and a second layer of a matrix material containing tungsten or boron may be arranged between the intermediate steel reinforced concrete member and the outer steel reinforced concrete member.

A single layer of a matrix material comprising tungsten or boron may be disposed between the inner steel member and the outer steel member. A single layer of a matrix material containing tungsten or boron may be disposed between the inner concrete member and the outer concrete member. A single layer of a matrix material containing tungsten or boron may be disposed between the inner steel reinforced concrete member and the outer steel reinforced concrete member.

The primary shield may include an inner steel liner and an outer steel liner, the base portion, the middle portion, and the top portion being sandwiched between the inner steel liner and the outer steel liner.

Although the present disclosure has referred to the use of steel for the support structure, it may be equally possible to use any other suitable metal, for example, nickel, aluminum, lead, titanium, and the like.

The steel or metal support structure may include a frame, e.g., an intermediate support structure, as appropriate.

Although the present disclosure has referred to a base material comprising tungsten and/or boron sandwiched between inner and outer support structures, it may be possible to fix a layer of base material comprising tungsten and/or boron onto an inner surface of the main shield layer in the intermediate region, or to fix a layer of base material comprising tungsten and/or boron onto an outer surface of the main shield layer in the intermediate region, or to fix a layer of base material comprising tungsten and/or boron onto an inner surface of the main shield layer in the intermediate region and to fix a layer of base material comprising tungsten and/or boron onto an outer surface of the main shield layer in the intermediate region.

The matrix material comprising tungsten or boron is completely encased within the support structure of the intermediate portion of the primary shield layer and is not visible, e.g., directly accessible, and is thus protected by the support structure of the intermediate portion of the primary shield layer.

It may be possible to use one or more other suitable neutron absorbing materials, e.g. silver, indium, hafnium, cadmium, in the matrix material, but taking into account the cost of these materials and whether they affect the manufacturability of the polymer material.

It may be possible to use other matrix materials such as metals. Suitable metal matrix materials are, for example, steel, stainless steel, mild steel, titanium or aluminum.

Although the present disclosure has referred to the heat exchanger 26, the turbine 28 and the generator 29 being arranged outside the building wall 24, it may be possible to arrange one or more of them inside the building wall 24, and they may be arranged inside the remote wall 20 and surrounded by the remote wall 20.

It will be understood that the present invention is not limited to the embodiments described above, and that various modifications and improvements may be made without departing from the concepts described herein. Any feature may be used alone or in combination with any other feature except where mutually exclusive, and the disclosure extends to and includes all combinations and subcombinations of one or more of the features described herein.