CN109801718B - Intrinsic safety pressurized water reactor with movable and separable reactor core - Google Patents

Abstract

The invention discloses an intrinsic safety pressurized water reactor with a movable and separable reactor core, which relates to the field of nuclear engineering. The intrinsic safety pressurized water reactor can avoid critical accidents of the reactor core under extreme accidents such as power failure of the whole plant, stick clamping, dilution system failure and the like, and has intrinsic safety to a certain degree.

Description

An inherently safe pressurized water reactor with movable core

technical field

The invention relates to the field of nuclear engineering, in particular to an inherently safe pressurized water reactor with a movable and separated core.

Background technique

Pressurized water reactor (pressurized water reactor), full name "pressurized water moderated cooling reactor". A reactor using pressurized, non-boiling light water (i.e. ordinary water) as moderator and coolant. It is composed of fuel assembly, moderator (also used as coolant), control rod assembly, combustible poison assembly, neutron source assembly, core basket and pressure shell. It is the reactor type with the largest number of applications and the largest capacity in nuclear power plants.

The existing pressurized water reactor core plus the water reflection layer is a whole in the shape of a cylinder. The reactor may have a criticality accident, resulting in the failure of the pressurized water reactor to shut down normally, so that the waste heat export and the containment of radionuclides cannot be achieved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to aim at the above-mentioned deficiencies of the prior art, to provide an inherently safe pressurized water reactor whose core can be moved and separated, which overcomes the problems of the existing pressurized water reactor in the event of a power outage accident in the entire nuclear power plant and superimposed stuck rods, Extreme situations such as dilution system failures have the potential for criticality to occur.

The purpose of the present invention can be realized by following technical scheme:

An inherently safe pressurized water reactor with a movable core, the inherently safe pressurized water reactor is composed of several movable parts of equal volume to form a cylindrical pressurized water reactor as a whole, through the core separation support system, under extreme accident conditions The parts are separated so that the core is in a subcritical state, and after the extreme accident is eliminated, the parts are closed so that the core can be re-critical.

Further, the sections have the same number of grids, the same number of fuel rods, the same number of control rods and combustible poisons to facilitate fuel management and reduce power peak factor.

Further, the core separation support system can ensure that under normal operating conditions, various parts of the core are in contact and not squeezed; under extreme accident conditions, various parts of the core are separated and reach a subcritical state; After the extreme accident was eliminated, the various parts of the core were reconnected and the critical state was reached again.

Further, the inherently safe pressurized water reactor is composed of four movable parts of equal volume to form a cylindrical pressurized water reactor as a whole.

Compared with the prior art, the present invention has the following advantages and beneficial effects:

The inherently safe pressurized water reactor with movable and separated cores provided by the present invention avoids the criticality of the core that may occur in the traditional pressurized water reactor under extreme accidents such as power outages in the whole plant, stacking sticks, and failure of the dilution system. The inherently safe PWR divides the core into several parts that can be split and moved, so that each part of the core can be separated under extreme accidents such as power failure of the whole plant and the failure of superimposed sticks and dilution systems. After separation, due to neutron leakage The increase of the PWR makes the PWR no longer critical, and can avoid the criticality accident of the core under extreme accidents such as power failure of the whole plant, stacking sticks, failure of the dilution system, etc. Therefore, the PWR proposed by the present invention will have a certain degree of safety. Inherent security.

Description of drawings

FIG. 1 is a schematic diagram of a conventional pressurized water reactor.

FIG. 2 is a schematic diagram of an inherently safe pressurized water reactor in which the core can be moved and separated according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of the separation of various parts of the inherently safe pressurized water reactor provided by an embodiment of the present invention under the control of the core separation support system.

FIG. 4 is a schematic diagram of each part of the inherently safe pressurized water reactor being closed under the control of the core separation support system according to an embodiment of the present invention.

Detailed ways

The present invention will be described in further detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example:

This embodiment provides an inherently safe pressurized water reactor in which the core can be moved and separated. The inherently safe pressurized water reactor is composed of several movable parts of equal volume to form a cylindrical pressurized water reactor as a whole. The parts are separated under extreme accident conditions to make the core in a subcritical state, and after the extreme accident is eliminated, the parts are closed so that the core can be re-critical.

In the event of a power outage accident in the entire nuclear power plant of the inherently safe pressurized water reactor, the core separation support system will split the cylindrical core into several parts, and these parts will then come out of contact, which will increase the neutron leakage. Therefore, the core is no longer critical, so as to fundamentally avoid the occurrence of criticality accidents. Therefore, compared with the existing pressurized water reactors, this embodiment proposes a pressurized water reactor with an innovative concept, which can It can automatically shut down under extreme conditions such as power and stacking sticks, dilution system failure, etc., so it has better inherent safety.

Since the effective multiplication coefficient of the pressurized water reactor can be expressed by equation (1):

k=εpfηx (1)

k in formula (1) represents the effective breeding coefficient of the PWR core. If k=1, the core is in a critical state; if k>1, the core is in a supercritical state; if k<1, the reactor is in a critical state The core is in a subcritical state. Under normal operating conditions, the PWR core is in a critical state, that is, the corresponding effective multiplication coefficient k=1; ε in equation (1) represents the fast neutron multiplication factor; p in equation (1) represents escape resonance absorption probability; f in formula (1) represents thermal neutron utilization coefficient; η in formula (1) represents the number of effective fission neutrons; x in formula (1) represents non-leakage probability. If the initial state is critical, then the initial k=1, if the core parts are separated at this time, the leakage probability of the core increases, that is, the non-leakage probability of the core decreases, that is, formula (1) If the x in the equation decreases, the k on the left side of the equation will also decrease, so that k<1, and the core will be in a subcritical state.

The existing pressurized water reactor core is added with a water reflection layer, which is approximately cylindrical, as shown in Figure 1. In order to increase its inherent safety, the PWR proposed in this embodiment is composed of several parts in the shape of a cylinder, as shown in FIG. 2 . Each part is controlled by the core separation support system. Under normal operating conditions, each part of the core is in a contact state, as shown in Figure 4, and the core is in a critical state at this time. However, in the event of an extreme accident such as the power failure of the whole plant and the failure of the stacking rods and the dilution system, each part can be quickly separated under the tension of the core separation support system, as shown in Figure 3. By observing the length of the expansion and contraction of the core separation support system, the intermittent length of the separation of each part of the core can be known. The greater the interval between parts, the more neutrons leak, and the smaller the probability of neutrons not leaking, then the corresponding effective multiplication coefficient is also smaller, so the subcriticality is deeper, and the occurrence of critical accidents under extreme accidents is avoided. .

After the extreme accident is eliminated, each part of the core can be slowly moved closer to each other under the pressure of the core separation support system. When the parts are in contact, the core separation support system will no longer squeeze each part of the core. , only play the role of fixed support. At this time, the neutron leakage decreases, and the effective breeding coefficient of the core gradually increases, which in turn makes the core slowly critical.

The above is only a preferred embodiment of the patent of the present invention, but the protection scope of the patent of the present invention is not limited to this. The technical solution and the invention patent concept of the invention are equivalently replaced or changed, all belong to the protection scope of the invention patent.

Claims (4)

1. An intrinsically safe pressurized water reactor with a movable and separable reactor core, which is characterized in that: the intrinsic safety pressurized water reactor is characterized in that a cylindrical pressurized water reactor whole body is formed by a plurality of parts which are movable in the same volume, the parts are separated under the extreme accident working condition through a reactor core separation supporting system, so that the reactor core is in a subcritical state, and after the extreme accident fault is eliminated, the parts are folded, so that the reactor core can be subcritical again.

2. The intrinsically safe pressurized water reactor of claim 1, wherein the reactor core is movable and separable, and the intrinsically safe pressurized water reactor comprises: the sections have the same number of grids, the same number of fuel rods, the same number of control rods, and burnable poison to facilitate fuel management and reduce power crest factors.

3. The intrinsically safe pressurized water reactor of claim 1, wherein the reactor core is movable and separable, and the intrinsically safe pressurized water reactor comprises: the reactor core separation support system can ensure that all parts of the reactor core are contacted and do not extrude under the normal operation working condition; under the extreme accident condition, all parts of the reactor core are separated to reach a subcritical state; after the extreme accident fault is eliminated, all parts of the reactor core are contacted again to reach the critical state again.

4. The intrinsically safe pressurized water reactor of claim 1, wherein the reactor core is movable and separable, and the intrinsically safe pressurized water reactor comprises: the intrinsic safety pressurized water reactor is a cylindrical pressurized water reactor whole body formed by four parts which are movable in equal volume.

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