DE1271269B - Multi-zone nuclear reactor with natural uranium as nuclear fuel - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

G21c

German: 21g -21/20

Number:
File number:
Aflnieldetag:
Display day:

1271269
P 12 71 269.5-33
April 16, 1960
June 27, 1968

The invention relates to a multi-zone atomic nuclear reactor with natural uranium as nuclear fuel in all zones, which is moderated _{with graphite and D 2 O, the zone moderated with D a} O being annular, containing several tubes distributed in the annular zone with fuel elements housed therein and is delimited both radially inward and radially outward by a graphite zone.

A multi-zone atomic nuclear _{reactor is already known, which is moderated with graphite and D 2} O, in which the heavy water zone consists of a number of tubes arranged in a ring and forms a central zone, which is inwardly and outwardly separated by a circular or a likewise ring-shaped zone with graphite as a moderator (U.S. Patent 2,865,826). Furthermore, a reactor which operates with enriched fuel is known. The zone division made here relates exclusively to the fuel concentration, but not to the moderator. Beryllium is used as a moderator in this reactor (US Pat. No. 2,852,456). Furthermore, it has already been proposed (cf. German Auslegeschrift 1215 822) to arrange zones moderated alternately with heavy water and graphite in a multi-zone reactor with natural uranium as nuclear fuel.

The invention is based on the consideration that the heavy water moderator zone is expediently embedded in the graphite zone. The first _{solution here is to design the D 2} O container in the form of a cylindrical hollow jacket. Given the large diameters required, however, considerable wall thicknesses are required in order to absorb the compressive forces that occur. Since high-purity aluminum _{, the material to be considered for the D 2} O container in this context, has a considerable neutron absorption cross-section, such a reactor would be difficult or not at all critical when operated with natural uranium.

The invention is based on the object of finding, in a multi-zone reactor, an advantageous structural solution for the zone division of the various areas with D ₂ O on the one hand and graphite as moderator on the other. It should be possible to manufacture and operate the entire reactor with justifiable technical effort. This is achieved according to the invention in the multi-zone reactor mentioned at the outset in that the D ₂ O moderator is arranged exclusively in the pipes forming this zone, each of which has several smaller pipes each with a multi-zone nuclear reactor with natural uranium
as nuclear fuel

Applicant:

Gutehoffnungshütte Sterkrade Aktiengesellschaft, 4200 Oberhausen, Lipperfeld 1

Named as inventor:

Julius Stelzer, 4200 Oberhausen-Sterkrade;

Dr. Erich Bagge, 2300 Kiel

Fuel element contains that further the zones moderated with graphite are formed radially inside and, with the exception of the entire outer reflector _{zone, also radially outside the zone moderated with D 2} O in such a way that, in a known manner, numerous seamlessly abutting graphite rods with polygonal cross-section a longitudinal bore and a smaller tube housed therein, also serving to hold a fuel assembly each, are arranged.

Through the use and suitable arrangement of these tubes, each one within the meaning of the invention Form part of the container for the heavy water and also due to their much smaller diameter can have a comparatively smaller wall thickness, there is an aluminum saving of 60% and more, so that the reactor can be made critical and put into operation by this alone can. In addition, the smaller amount of aluminum also has an advantage in terms of costs.

Further details of the invention are from the following description of the drawing for example and shown schematically in cross section embodiment of such a two-stage nuclear reactor to see.

Inside the cylindrical, upright pressure vessel 1 made of steel, there are several tubes 2 made of pure aluminum arranged in the form of a ring with small mutual distances. These tubes form the middle zone and are on both sides due to a larger number of polygonal graphite rods in cross-section 3, which form a circular inner zone and an annular outer zone.

The graphite rods arranged inside and up to a certain partial diameter d of the container 1 also outside the tubes 2 have a

809 567/427

Longitudinal bore and each contain an aluminum tube 4. Several tubes of the same type are uniform arranged distributed in each of the aforementioned larger tubes 2.

The tubes 4 are used to hold the fuel assemblies, not shown, which are known per se Way are arranged hanging and can be installed and removed from above. Also will a coolant for the centrally arranged fuel assemblies is passed through these tubes.

In the completely outer annular space between the container wall 1 and the partial diameter d , polygonal graphite rods 5 are also arranged, but without a longitudinal bore. These graphite rods form a reflector known per se.

Of the other details of the reactor, only the thermal one surrounding the entire container 1 should be mentioned here Shield 6 in the form of a lead layer traversed by cooling water pipes and the outside the same biological shield, arranged on all sides but not shown, from an even stronger one Concrete layer are mentioned.

Claims (1)

Claim: Multi-zone atomic nuclear reactor with natural uranium as nuclear fuel in all zones, which _{is moderated with graphite and D 2} O, the _{zone moderated with D 2} O being designed in a ring shape, containing several pipes distributed in the ring zone with fuel elements housed therein and both radially inside and outside is bounded radially outside by a graphite _{zone, characterized in that the D 2} 0 moderator is arranged exclusively in the tubes (2) forming this zone, each of which contains several smaller tubes (4) each with a fuel element housed therein the zones moderated with graphite are formed radially inside and, with the exception of the entire outer reflector _{zone (5), also radially outside of the zone moderated with D 2} O in such a way that numerous graphite rods (3) which are polygonal in cross-section and are seamlessly adjacent to one another without gaps with a longitudinal bore and one housed therein, also for receiving a fuel assembly di Ending smaller tube (4) are arranged. Considered publications:
German Auslegeschrift No. 1 079 751;
British Patent Nos. 841 992, 847 122;
U.S. Patent Nos. 2,865,826, 2,852,456. 1 sheet of drawings 809 567/427 6.68 © Bundesdruckerei Berlin