DE1764277A1 - Process for charging a gas-cooled high-temperature nuclear reactor - Google Patents

Description

BROWN BOI / ERI / KRUPP Reaktorbau GmbH Mannheim, the 3rd of February 1968

Pat / Shm / Ro. - R 170 -

"Method for charging a gas-cooled high-temperature nuclear reactor ¹¹

The present invention relates to a method of charging a gas-cooled high-temperature nuclear reactor with a bed of lumpy, e.g. spherical operating elements, the core of the reactor being divided into several axially parallel spaces and for each of the spaces own loading and unloading facilities are provided *

A gas-cooled nuclear reactor is already known (USA patent 3,034,689; "Atorakernenergie" magazine 5 3g. (i960) issue 3, pp. 93 to 96), whose core is divided into seven chambers by six hollow graphite cylinders and another space enclosed by them can be formed * In the hands of the graphite hollow cylinder there are channels for the control rods. The spherical fuel elements are filled into all seven chambers simultaneously from above and through a large pipe at the bottom Withdrawn again at the end of the reactor vessel; first the balls from the central chamber and then those from the outer chambers flow out * In another nuclear reactor of the same type (USA patent 3 22B 852) each of the seven chambers has its own charging system as well as a separate unloading device a continuous loading and unloading of the individual chambers instead of} i.e. all chambers are passed through by the fuel balls at the same time.

Furthermore, reference is made to the German patent application P 14 64 803.4, which also shows a nuclear reactor with a subdivided core. Which is in However, the space extending around the core axis remains free of fuel elements and serves as a mixed treoke for the heated cooling gas.

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As already mentioned, “ground at the well-known Kugalhaufen nuclear reactors all chambers are beacnicked with fuel elements at the same time. Ee is obvious that the fuel balls after passing through the reactor cores do not burn evenly, as there are long distances run through and the edge balls are also delayed by friction ■ ground. Any fuel balls appear on the exhaust pipe of the core The elderly, before their song usage, on their degree of burnout examined "must be grounded. In order to have a possible inside of the reactor cores To achieve a uniform density of power, it is necessary to use the Fuel balls with the greatest burn-up in the middle zone of the reactor » Enter kernels and the other chambers old friechen fuel - ·, to feed ments. For this reason, too, there is an elaborate burn-off measuring system required to measure the consumed by the aeniger consumed To be able to distinguish fuel balls. :

The present invention is based on the object of a gel-cooled High-temperature nuclear reactor of the type described above to achieve the most even burn-up of the operations alaaanta as well as one distributed as evenly as possible over the cross-section of the reactor core To achieve neutron flux and at the same time on a combustion measuring system to renounce. The solution to this problem is found in see that the establishment elements several times in succession from top to bottom the reactor cores are sent through the individual rooms. Provided that the flue pipes for the operational elements are centered are located beneath the individual rooms, the paths that e.g. Edge balls and the balls running through the vat dee Reuaea (in the following Called central spheres) in the reactor core, with «eitea no longer eo strongly differ, especially in the case of an undivided nucleus

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BATH ORIGINAL

This means that the operating elements have almost the same dwell time in the core and thus - in the case of Brannetoff elements - a uniform one Burn-off. After the operational elements have passed through an or Several rooms parallel to the axes are grounded - without a burn-off measurement takes place - a zveitea IaI by one or more "suppurative" axially parallel rooms sent. After this second pass you have the statistical differences in the degree of burnup of the fuel elements again reduced, and this process is repeated with each subsequent passage of the balls through the reactor core. Because every room has its own has its own loading and unloading facilities, the balls can do not mix with aolchen of another passage, and there is therefore no need to adjust the fuel elements to their degree of burnup to investigate.

During the last passage through the reactor core, the operating elements can be routed through the most important internal spaces or - if there are any - through a space extending along the axis of the core, thus reducing the neutron density in the center of the core and there a more uniform power density is achieved across the core cross-section. The burn-up of the fuel elements has now reached such a degree that they can easily be removed from the reactor. It is not necessary to discharge the burn-up gas, since the fuel elements do not show any great differences in their burn-up state after several passes. If the RSumbs traversed by the fuel elements have exactly the same dimensions, it can be assumed, according to the GaUB ¹ BOhBn ache probability distribution, that the relative spread of the burnout of the fuel elements after the time of passage by the factor SfT, after the third passage by the factor VT ua «· is reduced if it is taken into account that

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a burn-up measuring system works under operating conditions with a maximum accuracy of 5 % and that this value is even significantly worse due to the presence of fission product poisons, it is easy to see that after a certain number of runs the spread of the burn-up of the fuel elements has become so small, that a burn-off measuring system can be dispensed with.

This effect is achieved in that according to the present application Operating elements are not entered simultaneously - as is the case with the prior art - in all rooms of the reactor core, but that first a room or a group of rooms is charged and the operating elements pass through the other rooms one after the other.

The fact that the operating elements cannot mix with one another is therefore accurate known how many passes they have already done, which gives a statement about their burn-up status. If a centrally located room is in the reactor core is available, de) fuel elements to achieve a more even power density sent through this space before it burns out

In this case, too, the use of a burn-up measuring system can be dispensed with will; in the known nuclear reactors, however, it must be present to distinguish the fuel elements depending on their degree of burn-up and then to the to be able to give individual chambers.

Since each of the operating elements passes through the reactor core the same number of times, one all operating elements then have the same mechanical stresses during the loading process exposed; i.e. they suffer the same number of falls. The possibility that some of the drive elements have been exposed to too many shocks and break, that's excluded.

Another advantage is that the loading and unloading facilities can be formed more easily, since no

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BATH ORIGINAL

Power element is entered into a first space, from this to one second, third, etc. and finally after passing through the central room - if one is available - finally out withdrawn from the reactor · The guide for the operating elements can therefore can be greatly simplified, and a number of machines can be saved u / earth. The loading and unloading facilities can be for everyone Rooms be the same, thereby significantly reducing their costs, because, as is well known, the development costs for a certain construction take place a large proportion of the total manufacturing costs

It should also be noted that it is very beneficial to use the operational elements not to enter into the reactor core through the corner reflector, but the To lay the charging tubes in the partition walls between the individual lizard-parallel roughness and to let the balls emerge there · The fall path The balls are then only a few cm compared to a few inches in the previously common methods.

According to an advantageous development of the method according to the present invention Invention are not only fuel, but also breeding material elements entered into the nuclear reactor, with the fuel and brood palamenta until it is completely burned down, several of the Axis-parallel run through whispers one after the other · Then they become one Untarachaidungsanlaga supplied, e.g. according to the weight of the fuel balls eue the range of breeding material balls sorted out and their deduction initiated from the Basohickungakraislauf. Before passing through others aohaanparallala whispers are the Brutatoffalanantan fresh Brannctoffala- ■ er.fce admitted * after these are almost completely burned out

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BATH ORIGINAL

dia all operational elements - alao fuel and breeding material balls through then aich led into the Achaa daa Raaktorkarne extending space and then excreted from the feed acraial run.

The aich in dar Achaa daa cores extending space of surrounded by a concentric graphite and aich outwards This space adjoining ring zone is made up of a number of radially extending Graphite walls divided into other rooms. Both in the concentric Graphite wall ala can also be used in the radial varlaufandan walls Channels for control staff are provided aain.

Bai particularly large nuclear reactors can aa advantageously aain, the central one To divide the room into several rooms «This gives the possibility to to accommodate further shelves in the vicinity of the core center.

In the drawing there are two examples of execution of a nuclear reactor Implementation of the process of the invention shown echematiach, namely show

1 shows a section through a Raaktorkarn, only with fuel elements is charged, and

2 shows a section through a Raaktorkarn showing fuel and fuel Breeding material elements is baachickt.

Dia Fig. 1 shows in section dan kraiaförnigan Kerji ainee Raaktora, which is divided into several whispers. A central room 1 will be from a cylindrical graphite wall 2 unaohloaaan, between the and a dan Raaktorkarn ungabandan reflector 3 a ring remains free. The circular ring has through radial intermediate wounds 4, which fall off aua graphite and of glaioher thickness aind, in eeohe further space · p

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divided to 10. It is not necessary that these spaces be the same Dimensions have

All seven rooms have their own loading and unloading facilities equipped. Both in the graphite wall 2 and in the partition walls channels 11 are provided, which are intended to accommodate control rods. According to the method according to the invention, the charging of this reactor made in the following way:

Unused fuel balls are placed in the two opposite rooms 5 and 6 entered »deducted after going through these rooms and forwarded to rooms 7 and 8. After they also have the two opposite Have passed rooms 9 and 10, they will - without a burn-up measurement was made on them - a fourth ITlal through the reactor core sent through the central room 1. After being withdrawn from this room, they are removed from the feed circuit retired *

As already described earlier, the Brannetoff balls have changed after each pass by the reactor core, the relative statistical spread of their degree of burnup reduced by a certain value, so that now still accepted differences in the state of combustion of the individual balls can be.

A burn-up warning is therefore not necessary even now. As the fuel balls are already heavily consumed on their passage through the central room 1, the neutron and thus also the power density significantly reduced in this area.

Fig. 2 shows a section through a nuclear rector, which is a plane central space 1 as well as a ring space which, however, is not in

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six but divided into seven waiter · rooms 12, 13, ... 18 iat. All other features, ie the arrangement of the tubes and the construction of each room with their own loading and unloading devices, are the same as in the nuclear reactor shown in FIG. 1 and therefore in FIG. 2 omitted.
The loading process is as follows

Fresh fuel and breeding material elements «are placed in room 12, withdrawn from dieeem and fed to room 13. After going through this Room and the subsequent passage through room 14 ”, both spherical locations are sent through room 15. In the unloading device this A differentiation system has been put in place for the space that has been withdrawn Balls sorted according to their weight and thus the fuel balls separates from the breeding material balls. The fuel balls that are after the four core passages are completely consumed, «ground completely out of the Beechicküngekreiellauf canceled. The Brutatoffkugeln, however, since aie have a significantly longer lifespan, they go through even more four passes.

After separating the used fuel elements, “ground the brood furnace elements frieche fuel elements, and with theeon zueamman go through rooms 16, 17 and 18 one after the other Business elements checked through the central room 1, so "ohl the first Fuel ele also withdrew the raw material elements from the nuclear reactor ■ ground.

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Claims (4)

- * " J 178427? BROWN BOVERl / KRUPP Reaktorbau GmbH mannheim, dan 3. ffiai 195Θ Pat / Shm / Ro, - R 170 - Claim at Process for charging a gas-cooled high-temperature nuclear reactor with a bed of lumpy, e.g. spherical operating elements, with the core of the reactor in several axes parallel Rooms are subdivided and separate loading and unloading facilities are provided for each of the rooms, characterized in that the operating elements several times in succession from top to bottom by the to "earth" the individual rooms of the reactor core. 2) Method according to claim 1, characterized in that that soaiohl fuel and breeding material at the same time be guided in several passes through some of the axially parallel spaces (12, 13, 14, 15) that then after passing through A differentiation system removes the used fuel elements from the charging cycle and new fuel elements earth in a “space (16) parallel to the axis” through which they pass together with the elements of the breeding material, and that the fuel and Brutstoffelementa after Passing further axially parallel spaces (17, 18) in your last one Passage through the reactor core which is in the axis of the Core extending space (1) out «earth. 109825/0556 3) Nuclear reactor for carrying out the process according to the claims 1 or 2, characterized in that the space (1) extending in the axis of the cores is from a concentric graphite wall (2) and the axially parallel roughness (5, ... 10) by one number of the outer ring zone radially cutting graphite walls (4) are formed. 4) nuclear reactor according to claim 3, characterized in that that in the case of very large nuclear reactors it is enclosed concentrically by the graphite wall · space (1) is divided into several spaces. 109825/0556