DE2458016C3

DE2458016C3 - Nuclear reactor with several fuel tanks supported by vertical water pipes

Info

Publication number: DE2458016C3
Application number: DE19742458016
Authority: DE
Inventors: Antti Vaster a as Suvanto (Schweden)
Original assignee: AB Asea-Atom, V äster aas (Schweden)
Priority date: 1973-12-20
Filing date: 1974-12-07
Publication date: 1977-05-18

Description

Raum, der bei geeigneter Formgebung der Kassetten zwischen diesen entsteht, gemäß der Erfindung zur Aufnahme der Regelstabfinger dientSpace that arises between these with a suitable shape of the cassettes, according to the invention for Serves to accommodate the control rod finger

Anhand der in den Figuren dargestellten Ausführungsbeispiele soll die Erfindung näher erläutert werden. Es zeigenThe invention is to be explained in more detail on the basis of the exemplary embodiments shown in the figures will. Show it

F i g. 1 einen Reaktorkern gemäß der Erfindung mit einem Teil des Reaktordruckgefäßes im VertikalschnHt,F i g. 1 shows a reactor core according to the invention with part of the reactor pressure vessel in vertical section,

Fig. 2 eine.i Teil eines Horizontalschnittes längs der Linie 11-11 in Fig. 1,Fig. 2 a.i part of a horizontal section along the Line 11-11 in Fig. 1,

Fig. 3 einen Horizontalschnitt längs der Linie 111-111 in Fig. 1,3 shows a horizontal section along the line 111-111 in Fig. 1,

Fig.4 einen Vertikalschr.itt längs der Linie IV-IV in Fig. 3,4 shows a vertical step along the line IV-IV in Fig. 3,

F i g. 5 die Lage eines Fingerregelstabes im Verhältnis zu dem zugehörigen Wasserrohr bei einem Reaktor gemäß der Erfindung,F i g. 5 shows the position of a finger control rod in relation to the associated water pipe in a reactor according to the invention,

Fig.6 den Fingerregelstab gemäß Fig. 5 im Schnitt längs der Linie Vl Vl in Fig. 5.6 shows the finger control stick according to FIG. 5 in section along the line Vl Vl in FIG. 5.

Fig. 7, 8. 9 und 10 verschiedene Alternativen zu der Kassettenausbildung von F i g. 2.7, 8, 9 and 10 different alternatives to that Cassette design of FIG. 2.

In F i g. 1 bis 6 bezeichnet 1 das Druckgefäß und 2 den Moderatortank eines Kernreaktors. Der Reaktorkern, der mit 3 bezeichnet ist, ist von einem aus Blechmatenal hergestellten Kernrand 17 umgeben und enthält mehrere Brennstoffkassetten 4, die in direktem Kontakt miteinander angeordnet sind. Jede Brennstoffkassette hat eine Hülle 15 und enthält zwölf Brennstäbe 5.In Fig. 1 to 6, 1 denotes the pressure vessel and 2 the moderator tank of a nuclear reactor. The reactor core, which is denoted by 3, is one of Blechmatenal produced core rim 17 surrounds and contains several fuel assemblies 4, which are in direct contact are arranged with each other. Each fuel assembly has a casing 15 and contains twelve fuel rods 5.

Die Brennstoffkassetten 4 sind in Kassettengruppen 14 angeordnet, von denen jede neun Brennstoffkassetten umfaßt, welche auf einer gemeinsamen Kassettenaufstellplatte 6 ruhen, die oben ein Loch 7 für jede Brennstoffkassette hat, durch welche den verschiedenen Kassetten Wasser zugeführt wird. Jeder Kassettenaufstellplatte 6 wird die für sämtliche neun Brennstoffkassetten erforderliche Wassermenge über eine untere Öffnung zugeführt, die an das obere Ende eines Wasserrohrs 8 angeschlossen ist. Die Wasserrohre 8 haben nicht nur die Aufgabe, als Einlaßleitung für praktisch die gesamte, dem Reaktorkern zugeführte Wassermenge zu dienen, sondern haben ferner die Aufgabe, die ihnen jeweils zugeordnete Kassettenauf stellplatte 6 zu tragen und als Stütze and Führung für den Regelstabschaft und das Regelstabjoch zu dienen. Vier Kassettengruppen, d.h. sechsunddre'ßig Brenn-45 Stoffkassetten, bilden einen Kernmodul 16 leder Kernmodul 16 hat einen zugeordneten Regelstab. Der Regelsiab 10 ist ein Fingerregelstab, der sechzehn vertikale Regelstabfinger 11 hat, die an einem in einer Honzontalebene liegenden Joch 12 befestigt sind, das von einem zentralen Regelstabschaft 9 getragen wird. Das joch 12 ist eine Gitterkonstruktion und besteht im Prinzip aus vier miteinander und mit dem zentralen Regelslabschaft 9 steif verbundenen Ringen, von Jenen jeder ein Wasserrohr 8 umschließt und deren horizontale Lage im Verhältnis zum Wasserrohr dadurch fixiert wird, daß jeder Ring mit zwei Führungsrädern 13 versehen ist.The fuel assemblies 4 are arranged in assembly groups 14, each of which has nine fuel assemblies includes, which rest on a common cassette mounting plate 6, the top a hole 7 for each Has fuel assembly through which water is supplied to the various assemblies. Each cassette mounting plate 6, the amount of water required for all nine fuel assemblies via a lower one Orifice which is connected to the upper end of a water pipe 8 is supplied. The water pipes 8 not only have the task of serving as an inlet line for practically the whole of the reactor core supplied To serve the amount of water, but also have the task of holding the cassettes assigned to them supporting plate 6 and as a support and guide for to serve the control staff and the control staff yoke. Four groups of cassettes, i.e. thirty-six burn 45s Fabric cassettes, form a core module 16, leather core module 16 has an associated control rod. the Regelsiab 10 is a finger control stick that has sixteen vertical control stick fingers 11 attached to one in one Horizontal yoke 12 are attached, the is supported by a central control staff 9. The yoke 12 is a lattice structure and consists of Principle of four rings rigidly connected with each other and with the central rule lab 9, from those each enclosing a water pipe 8 and its horizontal position in relation to the water pipe is fixed in that each ring is provided with two guide wheels 13.

Bei der Ausführungsform der Erfindüngj die in den Figuren 1 bis 6 gezeigt ist, hat der Querschnitt der Brennstoffkassetten die Form eines Quadrats mit stark abgeschrägten Ecken. Die abgeschrägten Flächen 18 der Kassettenhüllen 15 bilden Kanäle 19 mit quadratischem Querschnitt, von denen einige als Leitrohre für die Regelstabfinger 11 des Regelstabes 10 dienen.In the embodiment of the invention in the As shown in FIGS. 1 to 6, the cross section of the fuel assemblies is in the shape of a square with strong beveled corners. The beveled surfaces 18 of the cassette shells 15 form channels 19 with a square Cross section, some of which serve as guide tubes for the control rod fingers 11 of the control rod 10.

Im allgemeinen ist eine BrennstoffTossettenhülle bei einem Reaktor gemäß der Erfindung im wesentlichen wie ein Hohlprisma ausgebildet mit mehreren ersten Seitenflächen, mit denen die Hülle in direktem Kontakt mit parallelen entsprechenden Seitenflächen mehrerer benachbarter Hüllen steht. Außerdem hat die Hülle zweite Seitenflächen, die zusammen mit entsprechenden zweiten Seitenflächen benachbarter Hüllen prismenförmige, vertikale Kanäle für Regelstabsfinger bilden. Bei dem in F i g. 1 und 2 gezeigten Reaktorkern werden nur Regelstäbe verwendet, bei denen sämtliche Finger für solche Kanäle bestimmt sind.Generally, a fuel tossette cover is included a reactor according to the invention formed essentially like a hollow prism with a plurality of first Side faces with which the shell is in direct contact with parallel corresponding side faces of several adjacent shells. In addition, the shell has second side surfaces, which together with corresponding second side surfaces of adjacent shells, prism-shaped, vertical channels for control rod fingers form. In the case of the FIG. 1 and 2 shown reactor core are only used control rods in which all Fingers are intended for such channels.

Anstelle von Brennstoffkassetten mit der in F1 g. 2 gezeigten Querschnittsform kann man gemäß der Erfindung auch Brennstoffkassetten verwenden, deren Hüllen zylindrisch sind oder abwechselnd gebogene und ebene Flächenabschnitte aufweisen, wie es in F1 g. 7 gezeigt ist, in der 20 die Hülle und 21 die Brennstäbe einer Brennstoffkassette gemäß der Erfindung bezeich nen. Die Regelstabsfinger sind mit 27 bezeichnet. Man kann auch Hüllen verwenden, bei denen gewisse Hüllenabschn'tte im Vergleich zu den in Fig. 7 gezeigten eine Biegung in entgegengesetzter Richtung aufweisen.Instead of fuel cassettes with the in F1 g. 2 The cross-sectional shape shown can also be used according to the invention, their fuel assemblies Sheaths are cylindrical or have alternating curved and flat surface sections, as in F1g. 7th is shown, in which 20 denotes the envelope and 21 denotes the fuel rods of a fuel assembly according to the invention nen. The control rod fingers are denoted by 27. You can also use covers that have certain Hull section compared to that in Fig. 7 shown have a bend in the opposite direction.

F i g. 8 zeigt einen Teil eines Reaktorkei ns gemäß der Erfindung, bei dem die Hülle 22 jeder Brennstoffkassette wie e:n vertikales Hohlprisma ausgebildet ist, dessen Querschnitt ein regelmäßiges Fünfeck ist. Die Regelstabfinger sind mit 23 bezeichnet.F i g. 8 shows part of a reactor core according to FIG Invention in which the envelope 22 of each fuel assembly how e: n vertical hollow prism is formed, the cross-section of which is a regular pentagon. The control rod fingers are denoted by 23.

Bei dem in F i g. 9 gezeigten Reaktorkern ist die Hülle 24 der Brennstoffkassetten wie ein Hohlprisma ausgeführt, dessen Querschnitt die Form eines regelmäßigen Dreiecks mit abgeschrägten Ecken hat. Durch die Abschrägung entstehen sechseckige, vertikale Kanäle 25. die für die Regelstabfinger 26> vorgesehen sind. Bei der in Fig. 10 gezeigten Ausfübrungsform der Erfin dung ist dasselbe Prinzip wie in Fig.9 angewendet, jedoch mit dem Unterschied, daß man hier von regelmäßigen Sechsecken stati von regelmäßigen Dreiecken ausgegangen ist.In the case of the FIG. The reactor core shown in FIG. 9 is the shell 24 of the fuel assemblies designed as a hollow prism, the cross-section of which has the shape of a regular Has triangle with beveled corners. The bevel creates hexagonal, vertical channels 25. those for the control rod fingers 26> are provided. In the embodiment of the invention shown in FIG The same principle is applied as in Fig. 9, with the difference, however, that regular hexagons are stati of regular Triangles.

Wie eingangs erwähnt, vermeidet man bei dem Reaktor nach der Erfindung gewisse Nachteile, die bei den bekannten spaltlosen Reaktorkernen häufig auftreten. Außerdem erhält man den Vorteil, daß man mit einer ungewöhnlich niedrigen Anzahl von Brennstäben in jeder Kassette arbeiten k.'nn. selbst wenn die Brennstäbe mit normaler Dicke ausgeführt sind. Gemäß Fig. 2 und F-" 1 g 4 ist die Anzahl der Drennstäbe prc Kassette /wolf Bei der Entwicklung eines Reaktor; gemäß der Erfindung ist min m einer Konstruktior gekommen, die besonders vorteilhaft ist. wenn die Anzahl von Brennstaben pro Brennstoffkassette kleine] als dreißig und größer als fünf ist.As mentioned at the beginning, one avoids certain disadvantages in the reactor according to the invention the well-known gapless reactor cores occur frequently. You also get the advantage of being with an unusually low number of fuel rods in each cassette will not work. even if the Fuel rods are made with normal thickness. According to Fig. 2 and F- "1 g 4, the number of spinning rods is prc Cassette / wolf When developing a reactor; according to the invention, min m is a constructor come, which is particularly beneficial. if the Number of fuel rods per fuel assembly small] than thirty and greater than five.

Hierzu 5 Blatt ZeichnungenIn addition 5 sheets of drawings

Claims

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Patent claims:

* 1. Nuclear reactor with several fuel assemblies supported by vertical water pipes vertically arranged, at least partially designed as hollow prisms, one of which predominant number has several first side surfaces with which they are in direct contact with parallel similar side faces of several adjacent shells are available, as well as with a number below the Control organs located at the core, each of which has a finger control stick with several control stick fingers, which are attached with their lower ends to a yoke carried by a control rod, characterized in that, in a manner known per se, the prismatic part of the cassette cover (15) has a number of second side surfaces (18) in addition to said first side surfaces, wherein a plurality of covers are arranged to one another in such a way that the outer sides of the cover sections, which correspond to the second side surfaces (18), a prismatic or cylindrical, vertical one Form channel (19, 25) and that this channel (19, 25) is provided for one of the control rod fingers (11, 26).

2. Nuclear reactor according to claim 1, characterized in that a predominant number of Control rod organs of the reactor are occupied in their entire capacity with control rod fingers (11, 26), intended for insertion into the vertical channels (19,25) between the fuel assemblies (4, 24) are

3. Nuclear reactor according to claim 1, characterized in that the cross section of said Hollow prism has the shape of a regular polygon with cut corners, the perimeter consists of several relatively long, straight sections that have a central section on each side of the correspond to regular polygons, as well as relatively short sections in between (18), which together with corresponding sections of neighboring hollow prisms form the circumference of a Form cross-section through said channel.

4. Nuclear reactor according to claim 3, characterized in that the regular polygon is a Square is.

5. Nuclear reactor according to claim 3, characterized in that the regular polygon is a Hexagon is.

6. Nuclear reactor according to claim 3, characterized characterized in that the regular polygon is a triangle.

7. Nuclear reactor according to claim 1, characterized in that each of the at least partially such as Hohlpnsmen formed shells (20) a cross section in the form of a regular pentagon having at least some of said first side surfaces with said second side surfaces are congruent.

8. Nuclear reactor according to claim 1, characterized in that that said yoke is arranged at least one in a horizontal plane and with the Control rod shaft (9) contains rigid mechanically connected ring which is vertically movable and encloses at least one water pipe (8) and mounted on the ring by means of a number on the Tubular surface of rollable guide wheels (13) in an unchanged position in relation to the cross-section of the Water pipe is held.

The present invention relates to a nuclear reactor according to the type mentioned in the preamble of claim 1. Such a nuclear reactor is known from DT-OS 23 23 584 and US Pat. No. 3,166,481.

The known nuclear reactors are designed with fissile cores, the fuel assemblies of which have an essentially square cross-section. Such a core structure can lead to the following difficulties: Due to the neutron radiation, the zirconium alloy used for the cassette shells is exposed to increased aging, ie the material is plastically deformed even with a relatively low mechanical stress, the degree of deformation increasing over time. Studies on cassette shells having a substantially square cross section, which have long been used in a fission reactor core have shown that each shell side had suffered a distortion in the way that the originally flat wall sections had become convex. Since cassettes of different ages are used in reactors, there is therefore a risk in a gapless reactor that a casing wall is pressed into the casing wall of an adjacent casing and that the cassettes are bent out at the edge.

In the publication "Directory of Nuclear Reactors" Vol. VII. 1968, pp. 76 and 7>, there is no gap Nuclear reactor with the essential square cassette cross-sections known, in which each cassette shell on one of its walls with an indentation extending over half of the wall is provided. The cassettes are like that among each other arranged that four such indentations touch each other, so that in the center of four cassettes forms cross-shaped channel. The difficulties of warping the sides of the cassette described at the beginning are practically not eliminated by this construction, since the majority of the cassette sides are full Cassette width and many such sides of adjacent cassettes are close to one another.

The present invention is based on the object of providing a nuclear reactor of the type mentioned at the outset Kind to develop in such a way that the extent of the aging-related deformations of the side surfaces the cassette shells is significantly reduced.

To solve this problem, a nuclear reactor according to the preamble of claim 1 is proposed, which according to the invention has the features mentioned in the characterizing part of claim 1.

Advantageous further developments and refinements of the invention are mentioned in the subclaims.

Bpi the deformations described above dei An Ar membrane effect plays a role in the shell walls of known reactors. In the same way as the maximum deflection of a membrane at constant pressure increases with the membrane area a maximum deflection of the cassette shells is also obtained. The invention is based on the Thoughts, the breadth of the interfaces between to reduce the size of adjacent cassette shells and in this way the deflection of the shell walls zi to decrease. This is achieved by the shaping of the cassette shells according to the invention. Both According to the invention, the width of each side of the cassette is smaller than the narrowest lateral projection of the cassette. Tuesday The resulting reduction in the envelope volume is compensated for by the fact that the envelope is no longer ft the control rod finger is used because de