CN109801718B

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

Info

Publication number: CN109801718B
Application number: CN201811490807.2A
Authority: CN
Inventors: 蔡杰进; 李志峰; 唐智洪
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2018-12-06
Filing date: 2018-12-06
Publication date: 2020-12-22
Anticipated expiration: 2038-12-06
Also published as: CN109801718A

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

Intrinsic safety pressurized water reactor with movable and separable reactor core

Technical Field

The invention relates to the field of nuclear engineering, in particular to an intrinsic safety pressurized water reactor with a movable and separable reactor core.

Background

Pressurized water reactors (pressurized water reactors), collectively referred to as "pressurized water moderated cooled reactors". A reactor with pressurized, non-boiling light water (i.e., plain water) as the moderator and coolant. The reactor core comprises a fuel assembly, a moderator (also used as a coolant), a control rod assembly, a burnable poison assembly, a neutron source assembly, a reactor core basket, a pressure shell and the like. The reactor type is the reactor type with the largest application quantity and capacity in the nuclear power station.

The existing pressurized water reactor core is added with a water reflecting layer, the reactor core is a whole body which is similar to a cylinder, if a nuclear power plant whole power outage accident occurs, under the extreme conditions that a rod is blocked, a dilution system fails and the like, the existing pressurized water reactor can possibly have critical accidents, so that the pressurized water reactor cannot be normally shut down, and therefore waste heat derivation and radionuclide accommodation cannot be achieved.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides an intrinsic safety pressurized water reactor with a movable and separable reactor core, and overcomes the defect that critical accidents can possibly occur in extreme situations of nuclear power plant power failure accidents, stacked rod jamming, dilution system failure and the like of the conventional pressurized water reactor.

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

the intrinsic safety pressurized water reactor with the movable and separable reactor core is characterized in that a cylindrical pressurized water reactor whole body is composed of a plurality of parts which are movable in the same volume, the parts are separated under the extreme accident 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.

Further, 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 factor.

Furthermore, 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 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.

Further, the intrinsic safety pressurized water reactor is formed by four parts which are movable in equal volume to form a cylindrical pressurized water reactor whole body.

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

the intrinsic safety pressurized water reactor with the movably separated reactor core provided by the invention avoids the critical reactor core accidents possibly occurring under the extreme accidents of the traditional pressurized water reactor such as the power failure of the whole plant, the superposition of the blocking rod, the failure of the dilution system and the like, and the intrinsic safety pressurized water reactor divides the reactor core into a plurality of parts which can be split and moved, so that all parts of the reactor core can be separated under the extreme accidents such as the power failure of the whole plant, the superposition of the blocking rod, the failure of the dilution system and the like, and the pressurized water reactor is not critical due to the increase of neutron leakage after separation, and the critical reactor core accidents occurring under the extreme accidents such as the power failure of the whole plant, the superposition of the blocking rod, the failure of the dilution system and the like can be avoided, so that the pressurized water reactor.

Drawings

Fig. 1 is a schematic view of a conventional pressurized water reactor.

FIG. 2 is a schematic diagram of an intrinsically safe pressurized water reactor with a movable and separable core according to an embodiment of the invention.

FIG. 3 is a schematic diagram of the separation of parts of an intrinsically safe pressurized water reactor under the control of a core separation support system according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the closure of parts of an intrinsically safe pressurized water reactor under the control of a core separation support system according to an embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the present invention is not limited thereto.

Example (b):

the embodiment provides an intrinsic safety pressurized water reactor with a movable and separable reactor core, wherein the intrinsic safety pressurized water reactor comprises a cylindrical pressurized water reactor whole body consisting of a plurality of parts which are movable in the same volume, the parts are separated under the extreme accident 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.

When the nuclear power plant outage accident happens to the intrinsic safety pressurized water reactor, the reactor core separation support system can enable the cylindrical reactor core to be split into a plurality of parts, the parts are separated from contact subsequently, neutron leakage is increased, the reactor core is not critical any more, the occurrence of the critical accident is avoided fundamentally, and therefore compared with the existing pressurized water reactor, the pressurized water reactor with the innovation concept is provided by the embodiment, the reactor core can be automatically stopped under extreme conditions of full reactor outage, stacked clamping rods, dilution system failure and the like, and therefore the intrinsic safety is better.

Since the effective multiplication factor of a pressurized water reactor can be represented by formula (1):

k＝pfηx (1)

k in the formula (1) represents an effective multiplication coefficient of the pressurized water reactor core, and if k is 1, the core is in a critical state; if k is greater than 1, the reactor core is in a supercritical state; if k <1, the core is in a subcritical state. Under the normal operation condition, the reactor core of the pressurized water reactor is in a critical state, namely the corresponding effective multiplication coefficient k is 1; the expression in formula (1) represents a fast neutron multiplication coefficient; p in formula (1) represents the escape resonance absorption probability; f in formula (1) represents a thermal neutron utilization coefficient; η in the formula (1) represents the number of effective fission neutrons; x in the formula (1) represents a leak-free probability. If the initial state is critical, the initial k is 1, and if the core parts are separated at the moment, the leakage probability of the core is increased, namely the non-leakage probability of the core is reduced, namely x in the formula (1) is reduced, then k on the left side of the formula is also reduced, so that k is less than 1, and the core is in the subcritical state.

The existing pressurized water reactor core is added with a water reflecting layer, and is approximately cylindrical, as shown in figure 1. In order to increase the intrinsic safety, the pressurized water reactor proposed in this embodiment is composed of several parts into a cylindrical shape, as shown in fig. 2. All parts of the reactor core are controlled by the reactor core separation support system, and under the normal operation condition, all parts of the reactor core are in a contact state, as shown in figure 4, at the moment, the reactor core is just in a critical state. However, when an extreme accident such as a station blackout, an overlap of rods, a dilution system failure, etc. occurs, the parts can be rapidly separated under the tension of the core separation support system, as shown in fig. 3. The intermittent length of each part separation of the reactor core can be known by observing the telescopic length of the reactor core separation support system. The larger the interval between each part is, the more neutrons are leaked, the smaller the probability that neutrons are not leaked is, the smaller the corresponding effective multiplication coefficient is, and therefore, the deeper the subcritical degree is, and the critical accident under the extreme accident is further avoided.

After the extreme accident is eliminated, all parts of the reactor core can be slowly closed under the extrusion of the reactor core separation supporting system, and when all the parts are contacted, the reactor core separation supporting system does not extrude all the parts of the reactor core any more and only plays a role of fixing and supporting. At this time, the neutron leakage is reduced, the effective core multiplication coefficient is gradually increased, and the core is gradually critical.

The above description is only for the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept within the scope of the present invention, which is disclosed by the present invention, and the equivalent or change thereof belongs to the protection scope of the present invention.

Claims

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.