LT5049B - Operating method of uranium-graphite channel reactor and control element for uranium-graphite channel reactor - Google Patents

Abstract

The invention relates to nuclear power engineering and to reactor control and protection systems. A control element has sections with neutron-absorbing material installed on a hanger in a channel being cooled. The sections are free to move along this channel. The control element has a sleeve accommodating twelve individual channels equally spaced from its longitudinal axis. These channels accommodate the neutron absorbing sections. Each such section is joined with the hanger. An outer diameter of the neutron-absorbing material containing section is chosen in accordance with diameter of the sleeve. The control element is entered into an working zone within an activated zone through its entire high thus speed of negative reactivity within working run intervals fulfils certain conditions. Thereby is ensured possibility to enter the control element in activated zone throughout its entire depth and amount of water in the channel is reduced in the activated zone, to reduce load on the drive, to enhance sp

Description

The present invention relates to nuclear techniques, namely, to the operation of channel reactors of uranografite RBMK type (reactive high power reactor) in negative reactivity emergency entry modes and to control and protection systems (RAS) of nuclear RBMK reactors.

Known state of the art

The operation of a reactor is controlled by varying the neutron multiplication factor by changing the rate at which it is produced, absorbed or leaked. In the event that the neutron flux density rises above the target value. adjusters are quickly introduced into the core, ideally by throwing the controls.

The design of the control devices depends on the type of reactor, the design of the core and the technological parameters of the reactor. The reactor type describes the properties of the heat transfer medium and determines its effect on the control devices. However, it is not possible to analyze one or another heat carrier separately from its operating parameters: temperature, pressure and phase state. Depending on the reactor type, the ducts where the control units are placed may be dry or wet, cooled or non-cooled. The core design defines the shape and basic geometry of the control unit.

Known mode of operation of a channeled uranium-graphite nuclear reactor used in IVKurchatov's name Beloyarsk NPP, which includes manual adjustment of reactance reserve compensation and automatic maintenance of the level of power provided, as well as providing the possibility of emergency reactivity introduction of negative reactivity (IJEmeljanov et al., KoHCTpynpoBaH M., Energoizdat, 1982, 199, 200 pages). In emergency mode, the known method employs a control device consisting of five links interconnected by pivots. Each link is a set of boron-containing alloy bushings. The boron alloy bushings are mounted on heat resistant tubes. The chains also have deflection rollers for the rod to move inside a dry vertical channel with double concentric thin walls made of poorly absorbing neutron material. When the adjusting device is dry, the bars reach a nominal temperature of 600-650 ° C. By interrupting the cooling of the duct, the bar temperature increases by 200-250 ° C.

The closest to the state of the art and achievable result compared to the descriptive method is the operation of a channel uranium-graphite nuclear reactor comprising the emergency introduction of negative reactivity into the working area by transferring at least one adjustable suspension and a chain with a neutron absorbing material (NADoležal, IJ). Emeljanov, KaHanbHbitf fląepHbiii 3HepreTMMecKnii ρββκτορ,

M., AT0MM3flaT, 1980, pp. 121-125).

The physical activity of the adjusting device when it is moved to the working position in the active zone depends to a large extent on the outside diameter of the neutron absorber in the absorption rod. Therefore, in order to increase the efficiency of the VAS in a limited number of VAS channels, it is necessary to choose the design with the largest absorber diameter. This means that the width of the gas gap should be at least 2-5 mm to ensure that the control unit with sequentially mounted circuits containing neutron absorbing material moves freely. The heat emitted from the chains with the neutron-absorbing material, at such a gas gap, will heat the shells of the chains to a temperature that is only allowed for expensive heat-resistant materials.

The closest to the state of the art and achievable result compared to the descriptive bod is a channel uranium-graphite nuclear reactor control unit having a link with a neutron-absorbing material arranged in a cooling channel in a suspension that can move along the cooling channel (IJEmeljanov et al., KoHCTpynpoepoeBaHiie Rix , M., Energoizdat, 1982, 200, 201). The regulator moves through a cooled channel passing through the graphite layer. Water is circulated in the cooling duct, removing heat from the regulator. The adjusting device shall consist of five articulated links. The ejector is teescopically connected to the first link in the direction of movement of the adjusting device. The last link in the direction of movement of the adjusting device is connected to a suspension which is connected to a flexible link. Each link is basically a tube with hermetically sealed ends. The ejector chains are filled with graphite. A known device ejector is required to displace water in a cooled channel when the links with the neutron absorbing material are raised, since water, when neutrons are strongly absorbed, affects the neutron-physical characteristics of the core. The specificity of RBMK is that the height of the VAS channel below the core is less than the height of the core. As a result, the length of the ejector is less than the height of the core, and the ejector is telescopically coupled to the absorber, i.e. within the active zone, as the chains with the neutron absorbing material are raised, the columns of water in the VAS channel remain uninhibited. In order to reduce these water poles, the known device has increased the length of the ejector by reducing the length of the absorber, which consequently does not enter the core over its entire depth.

In addition, the introduction of the known control device into the active zone during emergency mode is about 12-17 s.

Disclosure of Invention

It is an object of the present invention to provide a method of operating a channel uranium-graphite nuclear reactor and providing improved parameters for a channel uranium-graphite nuclear reactor regulator and for the first time realizing a cluster design in an RBMK type reactor.

The present invention has resulted in technical results which ensure the introduction of the control device to the full depth of the active zone, the reduction of water content in the VAS channel within the active zone, the reduction of the drive load and the speed of introducing the control device into the active zone.

these technical results are achieved by the fact that during operation of the channel uranium-graphite nuclear reactor, which involves the emergency introduction of a negative reactance with at least one control unit having a suspension and a neutron absorbing link, the control unit is arranged in parallel with the neutron linkage. absorbent material, each of which is coupled to a suspension, and transmitting at least one adjusting device to the stroke over the whole of its height in the active zone such that the mean velocity, W, of the emergency actuation of the negative reactance is such that:

W = K [p / (N) 3 where (1) p is the value of the negative reactivity introduced by the Control Devices when transferring to the stroke in the active zone, βθβ

N is the number of control devices transmitted to the stroke in the active zone;

K is the experimentally calculated factor selected from 0.133 to 0.223.1 / s.

The regulating device of a channel uranium-graphite nuclear reactor, which is provided with a neutron-absorbing link, which can be moved along the cooled channel by means of a suspension, has a bushing with 12 separate channels spaced at equal distances from the longitudinal axis of the bushing. absorbent material, in addition, each link is coupled to the suspension with a neutron absorbent material, and the outer diameter of the neutron absorbing link chain, dGR, is selected from 0.102d mm to 0.106d mm, where d is the outer diameter of the bushing.

A distinctive feature of the present invention is that the adjusting device is a parallel arrangement of neutron-absorbing material, each of which is coupled to a suspension, e.g. introduces at the same time not a monostrip in which the chains are arranged sequentially, but rather in a circle and parallel to each other with a efficiency not less than the monostrip. In addition, the control unit is put into emergency mode over the entire active zone, which significantly increases the absorption of neutrons over the entire active zone volume. Since the total path traveled by the control device is equal to the height of the active zone, it is necessary to formulate the control law of the control device such that the average emergency speed W of the negative reactance input during the stroke would satisfy the condition:

W = K * [p / (N)], where p is the value of the negative reactivity introduced by the control devices into the work zone during the passage, βθίΐ

N is the number of control devices transmitted to the stroke in the active zone;

K 'experimentally calculated factor selected from 0.133 to 0.233.1 / s.

This condition is determined by an experimental computational path. The formation of the necessary laws of motion of the control device and the corresponding signaling to the actuator shall be carried out in any known manner and shall not require any special knowledge.

Experimentally, when the K-value is less than 0.133 1 / s, the average reactance input W of the negative reactance within the operating range does not meet the required level of safety during reactor shutdown. If the value of K is greater than 0.223 1 / s, the average negative velocity W of the negative reactance input within the workflow boundary significantly diverges the energy release field through the height of the active zone.

a distinctive feature of the device is the introduction of a sleeve having 12 separate channels spaced equally from the longitudinal axis of the sleeve. The channels are equipped with links with neutron absorbing material, and each link with neutron absorbing material is connected to the suspension. The outer diameter of the chain with neutron absorbing material d _{GR is} chosen from 0.102d mm to 0.106d mm, where d is the outer diameter of the bushing. If the external diameter of the neutron absorbing chain is d _GR less than 0.102d, the efficiency of the adjusting device is insufficient to introduce the required negative reactivity within the operating range. When the outer diameter of the neutron absorbing chain d _{GR is} larger than 0.106d, it is difficult to fit 12 strands of neutron absorbing material with a gap between them in separate bushing channels.

It is expedient to make at least one link with the neutron absorbing material in a two-piece articulated joint and the link with the neutron absorbing material to be attached to the suspension eyelets.

The neutron absorbing material may be diphrosium titanate, and the sleeve may be made of aluminum alloy and filled with air at atmospheric pressure. The foregoing advantages and features of the invention will be further explained with reference to the accompanying drawings.

Brief description of the drawings

Fig. 1 is a perspective view of a channeled uranium-graphite nuclear reactor regulator;

Figure 2 is a sectional view taken along line A-A of Figure 1.

Description of the best embodiment of the invention

The regulator of the channel reactor of uranium-graphite nuclear reactor shall be fitted with a suspension 1 in the cooling channel 2 by a chain 3 with neutron absorbing material. Each link 3 is connected to the suspension 1 by the tabs 4, with a neutron absorbing material. The chains 3 are designed to move with the aid of a flexible link 5 coupled to the suspension 1 along the cooling channel. The flexible link 5 is connected to a gear not shown in the drawing. a bushing 6 is provided in the device having separate passages 7 spaced equally from the longitudinal axis of the bushing. The individual channels 7 are arranged in chains 3 with neutron absorbing material. The outer diameter of the neutron absorbing chain dGR is selected from 0.102d mm to 0.106d mm, where d is the outer diameter of the bushing. Ideally, the chains 3 with the neutron absorbing material consist of two parts hinged together. This would reduce friction when moving inside the individual channels 7. Chains 3 have a casing containing a neutron-absorbing material, which is dysprosium titanate. the sleeve 6 may be molded from an aluminum alloy to form individual ducts 7. the sleeve 6 may be filled with air or other gas at atmospheric pressure. the upper part of the bushing 6 is closed by a stopper 8. The chains 3 with the neutron absorbing material are cooled by water fed into the space between the bushing 6 by a cooling channel 2 through a pipe 9.

the device operates as follows: the bushing 6, closed by the plug 8, is inserted into the cooling duct 2 instead of the existing regulating device. The chains 3 with the neutron absorbing material, connected by the tabs 4 with the suspension 1, move simultaneously by means of a web link 5. The movement commands of the control device are formed by the center of the calculation, taking into account the neutron flux density of the energy dissipation fluxes, etc. Emergency negative reactance input shall be effected by transferring at least one control device into the stroke over the entire height of the stroke so that the mean negative stroke W stroke velocity W within the stroke is a condition (1).

Industrial applicability

The present invention can be successfully applied in the channel reactor uranium-graphite nuclear reactor in negative reactivity emergency introduction modes, the device can be manufactured by known devices, using standard technology, without creating any new devices in principle. The invention makes it possible to significantly reduce the time of introduction of control devices into the reactor core, which increases the operational safety of the reactor.

Claims (7)

1. A method of operating an analytical uranium-graphite nuclear reactor comprising the emergency introduction of a negative reactance through the transfer to a working zone of at least one suspension having a control device and a neutron-absorbing linkage, characterized in that the control device uses a parallel-linking neutron-absorbing linkage the material, each of which is coupled to a suspension, in addition moves at least one adjusting device through the stroke over its entire height in the active zone such that the negative reactance emergency injection speed W within the stroke range is such that: W = K [p / (N)] where (1) p is the value of the negative reactivity introduced by the control devices during transfer to the stroke in the active zone, β _β η N is the number of control devices transmitted to the stroke in the active zone; K is the experimentally calculated factor selected from 0.133 to 0.223.1 / s. 2. A regulator device for a uranium-graphite channel reactor having a neutron-absorbing link, which may be moved along the cooled channel, by means of a pendulum, characterized in that it has a sleeve with 12 separate channels spaced at equal distances from the longitudinal axis of the sleeve, having neutron-absorbing links, each link being coupled to a suspension with a neutron-absorbing material, and having an outer diameter of the neutron-absorbing material d _G R selected from 0.102d mm to 0.106d mm, where d is the outer diameter of the bushing. 3. The adjusting device of claim 2, wherein the at least one linkage to the neutron absorbing material is formed by two parts linked by a pivot. 4. Adjustment device according to claim 2 or 3, characterized in that the links with the neutron absorbing material are connected to the suspension eyelets. 5. A regulator as claimed in any one of claims 2 to 4, wherein the neutron absorbing material is diphrosium titanate. 6. Adjustment device according to any of claims 2 to 5, characterized in that the bushing is made of aluminum alloy. 7. An adjusting device according to any one of claims 2 to 6, wherein the bushing is filled with air at atmospheric pressure.