DE1489829A1 - Device for introducing reactivity into fast pulse reactors - Google Patents

Description

Device for introducing reactivity into fast pulse reactors

Known or proposed mechanical devices for introducing reactivity into fast pulse reactors consist essentially of two discs that carry highly neutron-sensitive material and either through the Reactor core or are moved along the outside of the reactor.

In one arrangement, the reactor core is split in half and has fissile material attached to the disks is moved through the gap. The main disadvantage of this system is that it is low on performance can work because it is difficult to dissipate the heat generated in the fissile material of the disc. This disadvantage occurs in a system in which the reactor core is constructed normally and the reactivity of discs is introduced on which reflector material is attached and which is located on the outside of the reflector along a window along the reflector, not one.

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The main problem with this approach is to ensure that the required amount of reactivity is really introduced will.

Both systems are inherently safe, i.e. if one or both panes break, the reactor becomes subcritical because it is designed to be subcritical under normal conditions.

The main object of the present invention is to provide a device for introducing activity with two disks which is insensitive to hit ζ ο generation and has a sufficient capacity for introducing reactivity and which at the same time allows the fast reactor to be subcritical normal conditions.

Another object of the invention is to provide a fast reactor which can generate neutron pulses of sharp, narrow shape and produced with a high output. The fast reactor described below is also from of the type with a split core and is equipped with a 2-shaft arrangement for introducing reactivity. According to According to the invention, the device for introducing reactivity is characterized in that at least one of the two Scheiden engages in the nuclear gap and equipped on its circumference with an annular zone of absorbent material which is interrupted by gaps in the absorber, while the

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other disc, if it works in the reflector area, carries reflector material locally near its edge and, when it is working in the reactor gap, locally near its edge carries fissile material.

As a result, the entire reactivity introduced is divided between the absorber gaps and the fuel blocks. she Lüoken bring the system from a definitely subcritical state to a somewhat delayed critical state, and the Fuel blöoke bring the system by a somewhat delayed critical to a somewhat overprompt critical state. Bas means that only a small amount of possibly diluted splittable material is required in each fuel block will. Thus the difficulties of removing heat from the fuel are minimized, more so than any Fuel block is only used once for η pulses. One Appropriate helium circulation in the window jacket facilitates heat dissipation.

As will be described in more detail later, the reactor becomes subcritical when one or both disks of the Break device for introducing reactivity. The following cases should be considered:

1. Only the ächeioe that carries the fuel breaks while the disc that carries the gaps between the regions

runs.

If that happens, even on a pulse peak, the absorber disc will dampen the power pulse, which Overprompt-critical state is no longer reached,

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and the system is held critical with a little delay. There is enough time to break the deadlock to operate. Therefore, no particularly dangerous situation will be reached.

2. Only the disc carrying the absorber breaks and the fuel disc continues to run.

In this case the system will reach the overprompt critical state every time the fuel is through the core is running. By correct selection of the ratios in the reactivity values of the fuel blocks and the Gaps can be provided for a sufficiently long time to actuate the quick release, and again will no particularly dangerous situation occurs. The gaps must be as large as the active zone of the Core and reflector.

3. Break both waves:

In this case, the system either behaves subcritically if the reactivity value of the absorber gaps brings it to a critical delayed state during normal operation, or as an overdelayed critical system if that is the state in which the absorber gap brings it to normal operation. In the first case there is no particular danger, in the second point the Heaktöi-aeit doroh correct interpretation ,

take a long time to think about a quick stop in ' *

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As a result of the target system proposed here, the dangers are reduced to a minimum, especially in with reference to the recently proposed method, which only uses discs that have absorber gaps. At the same time, there is less heat in the circulating fuel masses is generated, and the required amount of reactivity is brought into an area of flat flux distribution.

The invention is explained below with reference to the drawings, which schematically illustrate two embodiments of the invention show, described in more detail.

Figure 1 shows a pulsed, fast reactor system with central Pulaierungsplatten, which in the Intervene in a gap,

FIGS. 1a and 1b show side views of the pulping disks, and

FIG. 2 shows a pulsed, rapid reactor system with a central slit and a reflector slit and with two pulsation discs, one of which disk in the gap and the other ih engages the reflector gap.

The Reaktorayatem shown in Figure 1 contains a reactor core, which is divided into two parts 2 and 3 by a gap 1, and reflector blocks 4 and 51 which surround the core.

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Two pulsation disks 6 and 7, which engage the gap 1 of the reactor core from opposite sides, are fixed on the respective shafts 8 and 9. As can be better seen in Figureia, the disk 7 has an annular area 10 and T1 made of neutron-absorbing material, which is interrupted by two absorber-free zones, so-called absorber gaps 12, 13.

From Figure 1b it can be seen that the other disc 6 on its circumference at a uniform distance along the edge of the disc carries four blocks of fissile material 14-17.

The disks are via the gear unit 18, which controls the rotational speed of the two sheaths connected and synchronized, driven by a motor, not shown. The reactor becomes critical at overprompt when there is a gap in the absorber disk 7 and a block of fissile Material on the other notes 6 pass through the gap in the core at the same time. From this it can be seen that if there are η fuel blocks, each block only is used once in η power pulses.

In Figure 2 it can be seen that only one disc 7 ¹ engages in the gap 1 between the two halves of the core 2 'and'>'. Its function and construction is the same as that of the absorber disk 7 from FIGS. 1 and 1a. The other disk 6 'carries blocks made of neutron at the points where the disk 6 from FIG.

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reflective material because it works in the reflector zone of the reactor. It engages in a gap 19 in the reflector. The disks are coupled and driven via a transmission 18 ¹ which contains a motor. The discs are driven by the concentric shafts 8 'and 9'. The panes are coupled to one another in such a way that a reflector block in the circumferential gap and an absorber gap in the central gap coincide. The system is designed so that it "when both are off, comes in the intended überpromptkritisohen state" ⁿ robes? Fully engage from a sufficiently critical condition when both ⁿ Reaktivitätsproben.

The total reactivity introduced is divided between "samples", the relative amounts are for safety reasons fixed, i.e. that of the reflective blocks applied reactivity is kept as low as possible, so, as already described above, no dangerous situation in the event that the absorber disk breaks. From this it can be seen that also in this device To introduce reactivity, the hazards of broken glass are reduced to a minimum. The advantage over the one previously described is that no moveable Fuel is needed and that only * one slice through passes through the core. Here, too, can, the decisive one Part of the reactivity impulse around the promptly critical one State made very sharp around it, since tin β · ητ

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narrow reflector block can be used that moves past a narrow window. Any shifts the reflector disc, which can introduce instabilities, are of no great importance because the reactivity value of the reflector block is small.

Patent claims:

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Claims (2)

Patent claims: 1. Device for introducing reactivity for high-speed impulse reactors of the type with a split core, with two disks carrying highly neutron-sensitive material, indicated by the fact that at least one of the two bcheioen engages in the inner gap, where this disk with an annular one Umiangszone (y, 10; is made of neutron-absorbing material, which are covered by absorber gaps (, 12, 13j or areas of reduced absorption power, while the other pane, when it emerges in the reflector area, locally carries reflector material in the edge, and if it is in the iieactor gap arises, locally fissile material (.14, ^ 0t 16, 17j near inrem -ttand carries. BATH ORIGINAL -2- 903816 / OAOO H89829 10 2. Device according to claim 1, characterized in that the fissile material along the circumference of the disc in the form of mass units (14,15,16,17,) at the same distance and in a number which is greater than the number of absorber gaps ( is distributed 12,13) or the Retlektorklötze. JB / Ru - 1b 797 / 9ö 909816/0400