CN1016472B - Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor - Google Patents

Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor

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Publication number
CN1016472B
CN1016472B CN85106250A CN85106250A CN1016472B CN 1016472 B CN1016472 B CN 1016472B CN 85106250 A CN85106250 A CN 85106250A CN 85106250 A CN85106250 A CN 85106250A CN 1016472 B CN1016472 B CN 1016472B
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China
Prior art keywords
fuel
reactor
hollow section
proposed
briquet stove
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Expired
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CN85106250A
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Chinese (zh)
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CN85106250A (en
Inventor
埃伯哈特·托伊谢特
克劳斯-阿恩·哈斯
赫尔穆特·格温
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Forschungszentrum Juelich GmbH
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Forschungszentrum Juelich GmbH
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Priority to CN85106250A priority Critical patent/CN1016472B/en
Priority claimed from EP85111805A external-priority patent/EP0215152B1/en
Priority to DK21386A priority patent/DK21386A/en
Publication of CN85106250A publication Critical patent/CN85106250A/en
Publication of CN1016472B publication Critical patent/CN1016472B/en
Expired legal-status Critical Current

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    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00Energy generation of nuclear origin
    • Y02E30/30Nuclear fission reactors

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Abstract

The present invention is used to fill fuel into a briquette furnace type nuclear reactor. Firstly, fuel having high content of fission materials is partly filled to obtain a critical condition, such as preset power, and then new fuel gradually reduced is replenished with used fuel gradually increased. According to the size and the scale of the reactor, discharging fuel from the top after ten and more working years can be possibly realized by using a bottom panel with square concave holes arrayed in a grid shape. The sphere distance in the horizontal direction can be limited by the panel to reduce the force distributed on a furnace wall. Additionally, the force can be reduced by a conical furnace wall body. Particularly, a graphite rod used for absorbing the center is arranged in a reactor core in a large reactor.

Description

Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor
The invention relates to method and the briquet stove-type nuclear reactor that is applicable to this method with the different spheric fuel element filling briquet stove-type nuclear reactor of fissioner content.
The characteristics of briquet stove-type nuclear reactor are: can draw off spheric fuel element continuously from reactor, that is to say, withdraw from the spherical fuel element from reactor pressure vessel.New fuel element is then inserted by the charging pipe in the reactor shell wall reflection horizon.Charging and discharging are all carried out under the reactor full power state of operation continuously, perhaps exactly, and quasi-continuous carrying out.The time interval between twice charging is so short so that reactive fluctuation can not occur substantially, this fluctuation must by append into the neutron absorbing material regulated compensation.The length of interval time is between arriving several days several seconds.In such reactor, can realize favourable power density distribution and higher efficient.Certainly, drawing off fuel element under full power state of operation is need be comparatively expensive technical equipment.The gabarit height of reactor pressure vessel must reach 1~2 meter, so that can contain funnelform spheric fuel element escape hole, spheroid partitioning device and pressure gate.These equipment are inaccessible when place under repair.In addition, the equipment that shifts out the high radioactivity element that is unloaded also is expensive very big, handles and shelters because must carry out remote control.The operation of delivery device and maintenance and fuel element transport the fixing skilled work personnel that need continuously.
As everyone knows, the nuclear reactor that also has another kind of batch (-type) (discrete) charging.At regular intervals, for example have several days in 1 year or a few week with shutdown, cooling and decompression, so that the refuelling element.In the cycle of operation between twice charging process, must use neutron-absorbing material, compensate the changes of reactivity that is subjected to the fuel element fuel consumption impact to regulate.Usually adopt additional control rod, as boric acid in the coolant or flammable neutron absorbing material.Use these absorbing materials can increase the weight of expending of neutron, thereby reduce the conversion ratio and the rate of increase.In the use of this neutron absorbing material, from reactor, extract out mistakenly and produce certain security risk owing to control rod sometimes.
Basic task of the present invention is: a kind of like this reactor feed method is provided, adopt it not only eliminated economically shortcoming and the risk of known " intermittent duty ", and can avoid the discharging operation of the complexity under the running status.
Above-mentioned purpose can reach by following operation according to the present invention: draw off spheric fuel element batch (-type); To reactor fuel investment element the time, beginning is earlier with the high relatively fuel element filling part hollow section of fissioner content, so that reach critical conditions and predetermined electric power.Along with the burnup of fuel element increases, be the minimizing of fissioner content in the compensation reactor core, be continuously or quasi-continuously add fuel element, until being full of hollow section.Require to have the reactor of a suitable briquet stove-type, its design feature is for this reason: beginning is partly charging, adds charging again with backsight burnup situation.
In this charging method, first fuel loading is arranged like this: beginning as if the reactor core hollow section is the part charging, proper proportion is 1/4~2/3, particularly fill up 1/3 o'clock of hollow section, then under the predetermined power condition of reactor, can reach critical conditions (effective multiplication factor Kc=1) with fuel element.During the subsequent reaction stack operation, will load new fuel element continuous or quasi-continuously, and need to keep critical phase conditions moderately.When the reactor core hollow section of reactor is filled at last fully, then make reactor out of service, implement cooling and decompression, then all fuel elements are all drawn off simultaneously.The discharging of this mode is carried out once after 2~5 years about operation, and under low power density reactor situation (this reactor can be designed to cogeneration plant), then can carry out a discharging after carrying out 15~30 years.
For this mode that once all draws off charging, it is favourable using the spherical device for discharging of reactor core bottom, but is not to want.Without it, the reactor core hollow section also can by means of a kind of mechanical elevating conveying device or according to the suction cleaner principle from top emptied.This device for discharging can be used for the turned letter of the various reactors that move in such a way step by step.
Their production cost is correspondingly determined by expending of various reactors, equally also depends on running cost and personal services, and back two kinds of expenses are owing to using these devices to need payment.
In this charging method, drawing off than the discharging in common charging method operation of fuel element greatly simplified, because nuclear reactor is stopped operation, is cooled off and reduces pressure.But simultaneously, the briquet stove-type reactor is compared the advantage that also maintains oneself with other reactors, that is: need not use the neutron absorbing material to limit the reactor of the surplus that is produced by the fuel combustion circulation.
From what economic point of view will make every effort to reach be: this novel charging method, can provide with the reactor operation situation that adopts common charging method under identical thermal power.Because the reactor core hollow section begins just part charging, thereby the mid power density under the original state (comparing when being full of fully with the reactor core hollow section) will increase.For fear of the permission power (5.7 kilowatts/ball) that surpasses each fuel element, in being full of the heap internal volume of spheric fuel element, should make power density present uniform space distribution as far as possible at this.This can realize by following charging method: the beginning when filling with substance, will use two kinds of fuel elements that fissioner content is different at least.In " first charging ", below 2/3rds filling fissioner content than low about 12% the fuel element of mean value; And top three/ first load high about 24% the fuel element of fissioner content.
Also to further strive reaching from economic point of view: when reactor core is implemented discharging, the fuel mean value of fuel element should with the burnup identical (70~100 megawatt-day/kilogram (heavy metal)) that reaches in the common discharge way.Show that in a design estimation when the fissioner content in the fuel element of adding during than high about 1.9 times of the fissioner content mean value of initial part charging, above-mentioned target can reach.
The calculating simulation of slowly loading reactor with the identical fuel element of fissioner content is shown, necessary fresh fuel element loading speed will be more and more littler when cycle of operation convergence finishes every day, and the specific power of fuel sphere is loaded when beginning and convergence end all than higher.For addressing this problem, the different spheric fuel element of also available fissioner content is added charging.A precalculated computer simulation can be tried to achieve best fuel element load and fissioner content.
In above-mentioned reactor core is wanted charging method long-time out of service (this with the briquet stove-type reactor in fuel sphere circulation is different continuously), the density of fuel sphere can increase gradually, i.e. the increase of fuel sphere number in the unit volume.Therefore, in small-sized heap, there are control rod and last moment emergency shut down rod to place reflection horizon on every side.And no longer can be subjected in the bigger reactor of graphite reflector adjusting one or several graphite built in items cylindrical or the rib shape to be housed preferably, wherein can add neutron-absorbing material.This cylindrical structural is greatly simple than the structure of common briquet stove-type reactor, because do not have ball seat to the taking regular exercise of passing away, does not therefore have the effect or the influence of corresponding power.
According to the present invention, when fuel sphere long period in reactor core stops, should suitably insert fuel sphere lentamente, and take measures to make fuel sphere to insert the hollow section of reactor core as far as possible in an orderly manner.In this case, form the even distribution of loading, high power density and the fuel sphere upward pressure load of fuel sphere densification.
Bottom by means of the square grid of reactor core hollow section depression is inserted charging in an orderly manner, thus, when the fuel investment ball (from lowest part), may form best arrangement.For solving the burnup problem that the ball that causes owing to thermal distortion expands and crossed lifetime, the spacing between the pit of concave bottom is good with minimum, and is bigger by 1~8% than fuel sphere diameter, preferably big 5%.
Square grid one pit is arranged in the imagination best sexangle fuel sphere and arranged and have following advantage: when ground floor ball and other fuel sphere superpositions are got up, having optimal layer (every layer center four of lower floor above the fuel sphere), is to demarcate layer.Therefore, to core loading the time, naturally and understandably just obtain the arrangement order state as well as possible of the space density maximum of fuel sphere, formation is less than the sandwich construction of 45 ° sexangle tight pack, and can try to achieve coefficient of admission in theory is 0.74.
The marked difference of fuel sphere diameter and hollow section diameter allows the cylinder type hollow district to have certain disordered state near the wall place., in that event, hollow section transversal section and inwall still can adaptation to the ground become the orderly ordered state of fuel sphere.Like this, the big I of wall is according to determining the integer multiple of fuel sphere size, and reinforces with vertical rib, therefore also can form the orderly fuel sphere layer adjacent with wall.Unnecessarily facilitate the non-steady state arrangement of the dislocation layer fuel sphere on the bottom (as be upright in) of fuel sphere in the edge region, the radius-of-curvature of the groove that forms between rib should be greater than the fuel sphere radius, as shown in Figure 4.As an example, what Fig. 4 showed is level (part) transversal section of an octagon reactor core, by two kinds of dissimilar heap wall A and B, reactor core is limited in an orderly manner.A type heap wall suitably assembles with the vertical rib of being delineated out, and the available level and smooth or vertical ribbing as delineating of Type B heap wall is assembled.
Rectangular at hollow section, and be generally 2 nIndividual angle (n=2,3,4 ...) the transversal section on, the required rib structure that adds also produces simply by similar method.Generally, the fuel filling of the orderly arrangement of describing according to selected hollow section planimetric map and Tu Nei just can draw one and conform with the wall structure that purpose requires, basically as two outer rim overlayers of intersection fuel sphere layers mutually.
Sidewall discharging (as the orderly loading of realizing fuel sphere by the side working cycle) also can realize that this as shown in Figure 5 by increasing the reactor core transversal section from bottom to top.In this case, can design the outside surface of a rescinded angle taper, its inclination angle with respect to vertical or vertical plane (α) is 15 ° and 45 °, preferably (sees Fig. 5 a) for 25 °.
More favourablely be, in the core region of bottom, 1/3rd places below for example, the inclination angle (seeing Fig. 5 b) greater than upper zone can be selected in the inclination angle.Then better when about 25 ° of the inclination angle of the about 45 ° of upper areas in the inclination angle in following zone.
Preferably, the vertical profile of reactor core hollow section is overarched, causing the vertical effect component to pressure vessel wall all is equally big or small on the core height position.This can realize that by the moulding to the hollow section transversal section this moulding is approx by R=(R 0-a(Z-Z 0) 2Formula provides (seeing Fig. 5 C).In the formula, R represents the distance of reactor core hollow section central axis, R 0The distance of representing the ball filling surface, Z is a height and position, Z 0Be the height and position on the ball filling surface, a is calculated by the heap load value that wall allowed.
Below several accompanying drawings are illustrated, they are:
Fig. 1 represents the schematic construction by the briquet stove-type reactor vessel of the present invention's design;
Fig. 2 represents temperature and the power density of briquet stove-type reactor at different time;
Fig. 3 represents the bottom surface of band pit in the reactor core;
Fig. 4 is illustrated in the laminated stacking of the part of fuel ball in the octagon reactor core;
Fig. 5 represents the shape of various reactor core hollow sections, and their transversal section width increases from bottom to top.
According to Fig. 1, graphite reflector 2 is arranged in reactor pressure vessel 1, in it hollow space 3, it holds fuel sphere and fills out 4.These fuel spheres are packed into via charging pipe and discharge duct 5 or are drawn off.Adjusting control rod 6 is drafted and being placed in the reflection horizon.The fuel sphere filler is cooled off by helium, in the space 3 of hollow, helium get off again from getting on down and from about flow, leave the fuel sphere filler at last, from 8 discharges of following hot gas collection chamber.
The hollow parts volume of reactor core is 46 cubic metres, and the thermal power of generation reaches 200 megawatts.The helium of cooling usefulness flows downward, and is heated to 700 ℃ from 250 ℃.The diameter of fuel element is 6 centimetres, the uranium dioxide (UO that wherein contains 2) act as a fuel, exist with " coating particle " form.At the beginning when filling with substance, fill up 1/3rd of reactor core hollow section with fuel element.1/9ths fillings contain the fuel sphere of 5% enriched uranium wherein, above 1/9th fillings contain the fuel sphere of 7% enriched uranium, reach critical conditions through this.Little by little add the fuel element that contains 10.7% enriched uranium at run duration.350 fuel spheres are loaded in beginning every day, close on the cycle of operation when finishing, and load 210 fuel spheres every day.Dosing as required of they decided, so that reactor keeps critical conditions.After operation 611 all day, reactor is filled up fully, must carry out discharging.Burnup on average reaches 74 megawatt day/kilograms (heavy metal), is up to 105 megawatt day/kilograms (heavy metal).
Distribute power is more symmetrically axially beginning.Filling in servicely entirely, the power maximal value is shifted to top, and there is the fresh fuel element (see figure 2) of adding the there.At run duration, the maximum temperature of fuel is main transformerization between 735 ℃ to 910 ℃.Whenever therefore,, temperature all significantly is lower than 1250 ℃ of the maximum temperatures that allowed.Under situation is broken down in simulation, suppose that helium spills from reactor, calculating shows that temperature is up to 2005 ℃.The configuration of supposing reactor changes, 85 centimetres of the radiuses of graphite cylinder, and correspondingly the hollow section radius will increase by 22 centimetres, and under failure condition, the maximum temperature of fuel element is reduced to 1430 ℃ thus.The reduction of maximum temperature can avoid fission product to diffuse out from coating particle.

Claims (17)

1, method with the different spheric fuel element filling briquet stove-type reactor of fissioner content, it is characterized in that: the time to reactor fuel investment element, beginning is earlier with the high relatively fuel element filling part hollow section of fissioner content, so that reach critical conditions and predetermined electric power, burnup increase along with fuel element, minimizing for fissioner in the compensation reactor core, will be continuously or quasi-continuously add fuel element, until filling up hollow section fully, make reactor out of service during discharging, implement cooling and decompression, then all fuel elements are once drawn off.
2, the method that proposes according to claim 1 is characterized in that: be part fuel investment element to reactor core during beginning, the volume ratio that accounts for is 1/4 to 2/3.
3, the method that proposes according to claim 2 is characterized in that: be part fuel investment element to reactor core during beginning, the volume ratio that accounts for is 1/3.
4, according to the method for each proposition in the claim 1 to 3, it is characterized in that: in the initial part charging, below 2/3rds and top 1/3rd fuel elements that loaded in fissioner content, liken the average fissioner content low about 12% and the Gao Yue 24% that produce the critical conditions basis into initial part charging respectively to.
5, according to the method for each proposition in the claim 1 to 3, it is characterized in that: fissioner content is than high about 1.9 times of the fissioner average content of the fuel element of initial part when filling with substance in the fuel element of adding.
6, according to the method for each proposition in the claim 1 to 3, it is characterized in that: core unloading begins from above to carry out.
7, according to the method for each proposition in the claim 1 to 3, it is characterized in that: carry out orderly filling to reactor core with fuel element.
8, adopt aforesaid right to require the briquet stove-type reactor of the loading method that proposed, have the hollow section that holds fuel element, comprise initial charging, fuel element handling device, have heat exchanger, the heat-extraction system of coolant circuit and fan blower is characterized in that:
One is contained in the hollow section that load is in the initial charging of critical conditions down, and this initial charging only occupies the part of hollow section,
Support reactor core to make the fuel element bottom surface of the band pit of filling in order for one.
9, according to the briquet stove-type reactor that claim 8 proposed, it is characterized in that: the extraction device of fuel sphere is in the hollow section upper end.
10, according to the coal dust ball stove reactor that claim 9 proposed, tool is characterised in that: the pit on the reactor core bottom surface is foursquare grid-like arrangement, and the pit spacing is that the point of crossing spacing reaches minimum, and is bigger by 1~8% than fuel sphere diameter, and preferably big 5%.
11, according to the coal dust ball stove reactor that claim 10 proposed, it is characterized in that: have 2 nThe hollow section transversal section at individual angle wherein n is a integer more than or equal to 2, and its marginal dimension is corresponding to the integral multiple of fuel sphere diameter.
12, according to the briquet stove-type reactor that each proposed in the claim 9~11, it is characterized in that:, perhaps on the hollow section inwall, process pit for coating the ribbing of desirable fuel sphere configuration structure.
13, the briquet stove-type reactor that is proposed according to claim 8 or 9 is characterized in that: the transversal section of hollow section increases from bottom to top gradually.
14, according to the briquet stove-type reactor that claim 13 proposed, it is characterized in that: the shell surface of a frustum shaped is arranged, and the angle of itself and vertical plane is 15 ° and 45 °.
15, according to the briquet stove-type reactor that claim 14 proposed, it is characterized in that: the shell surface of a frustum shaped is arranged, and the angle of itself and vertical plane is about 25 °.
16, according to the briquet stove-type reactor that claim 14 proposed, it is characterized in that:
The bottom 1/3rd of shell surface is about 45 ° with the inclination angle of vertical plane, and its top 2/3rds is about 25 ° with the inclination angle of vertical plane.
17, according to the briquet stove-type reactor that claim 8 proposed, it is characterized in that: graphite post or rib are arranged in the reactor core hollow section, can control and stop the neutron-absorbing material that reactor carries out to hold.
CN85106250A 1985-08-19 1985-08-19 Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor Expired CN1016472B (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
CN85106250A CN1016472B (en) 1985-08-19 1985-08-19 Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor
DK21386A DK21386A (en) 1985-08-19 1986-01-16 PROCEDURE FOR FILLING A BALL FILLING REACTOR AND SUCH A BALL FILLING REACTOR

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN85106250A CN1016472B (en) 1985-08-19 1985-08-19 Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor
EP85111805A EP0215152B1 (en) 1985-09-18 1985-09-18 Method for loading a pebble bed nuclear reactor, and pebble bed reactor therefor

Publications (2)

Publication Number Publication Date
CN85106250A CN85106250A (en) 1987-02-18
CN1016472B true CN1016472B (en) 1992-04-29

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CN85106250A Expired CN1016472B (en) 1985-08-19 1985-08-19 Loading process for briquet stove type nuclear reactor and the corresponding briquet stove type nuclear reactor

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1296939C (en) * 2005-08-26 2007-01-24 田嘉夫 Regular bed modular high temperature gas cooled reactor and its fuel sphere disposal method
CN114171222B (en) * 2021-11-25 2024-06-04 中国工程物理研究院核物理与化学研究所 Reactor refueling system and online loading, unloading and refueling method

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DK21386D0 (en) 1986-01-16
CN85106250A (en) 1987-02-18
DK21386A (en) 1987-02-20

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