DE1192334B - Loading and unloading system for a gas-cooled nuclear reactor - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY GERMAN 4lffl9Wl · PATENT OFFICE Int. CL:

G 21

EDITORIAL

German class: 21 g - 21/20

Number: 1192334

File number: S 71374 VIII c / 21 g

Filing date: November 23, 1960

Opening day: May 6, 1965

The invention relates to a loading and unloading system for a gas-cooled nuclear reactor.

It is desirable that the loading and unloading of the fuel assemblies in a gas-cooled Nuclear reactor is running while the reactor is operating under load. Constructions with which this can be achieved, consist of a charging container to be arranged outside the reactor pressure vessel, which contains a magazine for stacking fuel assemblies, and a loading tube, which can be connected to the pressure vessel of the reactor in order to remove fuel elements from Transfer the feed container into the reactor channels or from the reactor into the feed container.

In such systems, however, there is the disadvantage that the resistance to the gas flow through any particular reactor fuel duct changes with the number of fuel assemblies in the channel, and the resulting change the thrust acting on the fuel assemblies during loading and unloading can be very disabling and z. B. cause a lifting of the fuel assemblies, which is undesirable.

In the invention, a loading and unloading system is now proposed, which is characterized is that an additional tube is provided on the feed container, which is connected to the reactor pressure vessel can be connected and thus a return flow path for the gaseous reactor coolant can form, the arrangement being made so that the fuel assemblies during the loading and discharge process remain in a closed gas flow path, which is of the Feed tank, the feed pipe, the reactor pressure vessel and the additional pipe are formed will, and offer a substantially constant resistance to the gas flow.

Compared to the existing one, a loading and unloading system is created in which the thrust remains constant, which overcomes the disadvantage indicated above.

Two embodiments of a loading and unloading system according to the invention are given as examples described in connection with the schematic drawing. It shows

Fig. 1 is a schematic representation of a loading and unloading system,

F i g. 2 is a plan view of a detail of the installation according to FIG. 1,

3a, 3b and 3c are schematic representations Loading and unloading system for a gas-cooled nuclear reactor

Applicant:

Simon-Carves Limited, Stockport, Cheshire;
The General Electric Company Limited,
London (Great Britain)

Representative;

Dr.-Ing. H. Ruschke and Dipl.-Ing. H. Agular,

Patent Attorneys, Munich 27, Pienzenauer Str, 2

Named as inventor:

James Lewis Ayre,

Peter Raymond Gledhill, Erith, Kent

(Great Britain)

Claimed priority:

Great Britain dated November 25, 1959 (40 037)

to explain the working principle of the system according to FIG. 1,
F i g. 4 and 5 details of another embodiment of a loading and unloading installation according to the invention.

1 comprises a gas cooled nuclear reactor a moderator core 1 formed with a large number of vertical passages 2, wherein only one passage is shown. These passages are arranged to pass fuel assemblies such as e.g. the fuel assemblies 3 can accommodate. The Keml is enclosed in a pressure vessel 4 through which Pipes 5 and 6 are connected to the upper and lower ends of a heat exchanger 7, respectively. in the Heat exchanger 7 is a fan (not shown) for circulating cooling gas that goes up flows through the channels 2 to extract heat from the fuel assemblies.

In order to be able to change the fuel element while the reactor is in operation, a loading and unloading machine arranged above the pressure vessel 4 is provided; this essentially comprises a loading container 10 in which a magazine 11 is provided for the stacking or storage of fuel assemblies 3, a fuel assembly gripper 12 and a loading

509 568/313

tube 13, which is gas-tightly connected to the charging container 10 and to the upper end of each Channel 2 can also be connected in sequence in a gas-tight manner. In general runs the feed pipe 13 through a standpipe which surrounds the pipe 13, and at one End with the charging container 10 and at the other end with the pressure vessel 4 in each case gas-tight connected is. The rotatable magazine 11 has a cylindrical shape and the feed pipe 13 runs through this along its axis upwards. Around the axis of the magazine is a number Tubes 14 arranged in which the fuel assemblies can be stacked. An additional pipe 15 connects the feed container 10 and the pressure vessel 8. The upper end of this tube 15 is designed so that it can cooperate with each of the tubes 14 in turn when the magazine is rotated, and the lower end is connected to the vessel 4 via an opening 16 in a gas-tight manner.

Fig. 2 shows a plan view of the magazine 11, four stacking tubes 14 being arranged around the central charging tube 13.

When loading and unloading the reactor under load, cooling gas continues to flow through the core 1 and through the heat exchanger 7. The cooling gas flowing in the channel 2 to which the feed pipe 13 is connected, but does not go directly to the pipe 5, but flows through the Tube 13 into the feed tank 10. This gas flows through tubes 14 and 15 into the upper one Part of the pressure vessel 4 back and then flows through the pipe 5 to the heat exchanger 7 in this way, the fuel assemblies in the channel 2, in the feed pipe 13 and in the stacking pipe are defeated 14 a constant thrust. The tube 15 can be omitted, in which case the backflow of the gas through the tube 14 into the space between the magazine 11 and the inner walls of the loading container 10 and back into the upper part of the pressure vessel 4 through the space between the feed pipe 13 and a surrounding standpipe.

The principle of the invention is illustrated in FIG. 3. Fig. 3a shows a fuel channel 2 of the reactor core, in which eight fuel assemblies 3, the are stacked in a tube 14 in the magazine, are to be used. All elements are located in the branch of the coolant circuit with downward flow. Fig. 3b shows the arrangement when three elements 3 have been inserted into the channel and five have remained in the magazine. F i g. 3c shows the arrangement when all elements have been inserted into the channel, which are now a total are in the branch of the coolant circuit with an upward flow. F i g. 3 is a schematic representation in which the pressure vessel 4, the heat exchanger 7 and the charging container 10 are not shown; the one marked at 17 Coolant branch with a downward flow accordingly comprises the pipe 15, the pressure vessel 4, the heat exchanger 7 and the tubes 5 and 6.

In the arrangement according to FIGS. 4 and 5, the feed pipe 13 is outside the magazine 11, and the cooling gas flows to the pressure vessel 4 via a standpipe 18 which is the lower part of the feed pipe 13 surrounds, back.

In addition, a magazine cooling circuit is used, which contains a fan 20, which at Actuation pulls part of the cooling gas through the tubes into a loading or preheating position. The gas in this flow circuit flows through a pipe 21 which is connected to the manifold 22 through a manifold upper ends of the respective tubes 14 and connected to a gas-air heat exchanger 23 is surrounded, with any heat of decay of

ίο discharged fuel in the magazine diverted and flows back into the hopper 10. It will be noted that during the loading and discharging the temperature of the cooling gas flowing through the magazine increases according to the number Changes fuel elements that remain in the coupled channel of the reactor core. During loading the temperature rises, and during discharging it falls.

In addition, there is a channel loop circuit 24 through which the cooling gas exits when surfacing the tube 14 flows from which fuel assemblies 3 are removed at the specific time. This Circuit 24 includes a pipe 25, a fan 26 and an evaporative cooler 27. By controlling the Fan 20 can provide the additional resistance to gas flow provided by fuel assembly gripper 12 and other components of the loading and unloading machine are compensated, and the channel loop circuit 24 can be used to regulate the temperature of the cooling gas.

A preheating circuit is used for preheating or cooling the fuel assemblies 3 in the tube 14 28 present, which contains a fan 29, a heater 30 and a cooler 31, wherein a tube 32 of the circle 28 is arranged for connection to the special tube 14 when the magazine is rotated.

Claims (5)

Patent claims: 1. Loading and unloading system for a gas-cooled nuclear reactor, consisting of one outside of the reactor pressure vessel to be arranged charging container, which is a magazine Contains stacking of fuel assemblies, and from a feed tube that connects to the pressure vessel of the reactor can be connected to fuel assemblies from the feed tank into the Transferring reactor channels or from the reactor to the charging container, characterized in that that an additional tube is provided on the feed container, which can be connected to the reactor pressure vessel and can thus form a return flow path for the gaseous reactor coolant, the arrangement is made so that the fuel assemblies during the loading and unloading process remain in a closed gas flow path leading from the feed tank, the feed pipe, the reactor pressure vessel and the additional pipe is formed, and offer a substantially constant resistance to the gas flow. 2. loading and unloading system according to claim 1, characterized in that the additional The pipe concentrically surrounds the part of the feed pipe lying between the feed container and the reactor vessel, where- through an annular space for the return flow path arises. 3. Loading and unloading system according to claim 1 or 2, characterized by additional Devices for heating or cooling the ones in the loading container Fuel elements by means of a flowing gas. 4. loading and unloading system according to claim 1, 2 or 3, characterized in that the return path contains a cooler. 5. loading and unloading system according to claim 4, characterized in that the cooler is an evaporative cooler. Considered publications:
German Auslegeschrift No. 1045 003,
985; "The British Nuclear Energy Conference", Vol. 2, ίο No. 2, April 1957, pp. 146 to 152. 1 sheet of drawings 509 568/313 4.65 © Bundesdruckerei Berlin