EP0803125A1 - Verfahren und vorrichtung zum betrieb eines reaktors im instabilen zustand - Google Patents
Verfahren und vorrichtung zum betrieb eines reaktors im instabilen zustandInfo
- Publication number
- EP0803125A1 EP0803125A1 EP96900255A EP96900255A EP0803125A1 EP 0803125 A1 EP0803125 A1 EP 0803125A1 EP 96900255 A EP96900255 A EP 96900255A EP 96900255 A EP96900255 A EP 96900255A EP 0803125 A1 EP0803125 A1 EP 0803125A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- area
- reactor
- monitoring
- signal
- alarm
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21D—NUCLEAR POWER PLANT
- G21D3/00—Control of nuclear power plant
- G21D3/08—Regulation of any parameters in the plant
-
- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C7/00—Control of nuclear reaction
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
-
- Y—GENERAL 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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
Definitions
- the invention relates to a method for operating a sieve water reactor which is in an unstable state due to local oscillation of a physical quantity (in particular the power or the neutron flow associated therewith).
- the invention also relates to a device for carrying out this process and to a method and a device for monitoring this unstable reactor state.
- the nuclear fission which determines the performance of a nuclear reactor is controlled in that absorber elements are inserted into the reactor core in order to weaken the neutron flow. Thereby, measuring lances with sensors for the flow of thermal neutrons are distributed over the reactor core in order to detect the actual state.
- the throughput of cooling water which also serves as a moderator, must also be adapted to the respective state.
- This cooling water enters the reactor core as a liquid from below, flows through the fuel elements in which it partially evaporates, and exits the core as a vapor / liquid mixture, as a result of which the fuel / moderator ratio changes in the different parts of the Fuel elements changes.
- the flow conditions also change, in particular the location at which the 1-phase flow with which the liquid coolant enters the fuel elements changes into the 2-phase flow of the liquid / vapor mixture.
- unstable states have been observed in which this phase boundary starts to oscillate, which results in a pulsation of the moderator density and the power that leads to the cooling power and the movement of the phase boundary ⁇ reacts. Periodic Temperature fluctuations with considerable peak values occur.
- the maximum permissible output of the fuel elements is mainly limited by the temperature resistance of the materials used in the fuel elements. If an upper temperature limit is exceeded, these materials lose their mechanical, chemical and physical properties and can undergo irreversible changes which can force the fuel elements to be replaced. It must therefore be ensured that this thermal-hydraulic power limit (and thus a thermal-hydraulic limit value A ⁇ h of the neutron flux) is not exceeded in the reactor.
- the operating permits for the reactors therefore provide that, if a limit value is exceeded, the reactor is switched off quickly (so-called "SCRAM"), in which all control rods are quickly retracted and the corresponding cooling capacity is set after an emergency program.
- the reactor After such a SCRAM, the reactor has to be started again according to an operational start-up program, so that the reactor operation is considerably disturbed.
- the fuel assemblies must be replaced for safety reasons if the thermal-hydraulic limit value has been reached several times or over a long period.
- the aim is to detect and dampen such an unstable condition as early as possible before these power pulsations come close to the thermal-hydraulic limit value.
- Each of these four sensors in each measuring probe is used, two sensors being assigned to a first monitoring system and the two remaining sensors being assigned to a redundant second monitoring system.
- Each monitoring system contains two monitoring channels, each sensor signal of a measuring probe being assigned to another monitoring channel.
- the two monitoring channels of a system are based on different subdivisions of the reactor into individual areas (“monitoring cells”), each cell being limited by four measuring lances to form a corresponding area signal.
- a sensor signal in each monitoring channel belongs to two, three or four cells. This multiple use of the sensor signals is intended to make it possible to monitor and identify practically the condition of each individual fuel element due to its influence on the sensor signals of the individual cells. For this purpose, it is provided that an alarm is only set in a system if both monitoring channels respond. It is sufficient for the alarm if it is given by one of the two systems; however, this only provides simple redundancy.
- Another disadvantage is that a faulty measurement or a complete failure of a measuring probe affects practically all monitoring channels.
- the condition of the individual cells (areas) is monitored by first monitoring in a plausibility check whether the individual sensor signal exceeds a certain lower limit value and is working properly. In the event of a sensor defect, the signals belonging to this cell are no longer evaluated.
- a current area signal is formed by summation of all sensor signals of a area, but this is suppressed if (for example due to incorrect measurement) a plausibility monitor shows that the area signal does not reach a predetermined minimum value.
- the area signal is then filtered and related to a time average whose time constant is greater than a period of the oscillation, so that a relative current area signal is produced which indicates the percentage by which the current power of the area is above or below that Mean value.
- this current value exceeds a performance limit (eg 120%), it is checked whether this is a one-time transition state (so-called "transient"), which is e.g. B. represents only an aperiodic settling to a new operating state specified by the control system without stimulating an oscillation. In this case, there is therefore no critical oscillation in the frequency band 0.3 and 0.7 Hz, so that no intervention takes place unless a limit value h IXayi in the vicinity of the thermal-hydraulic limit value A t k has been reached.
- a performance limit e.g 120%)
- a corresponding limit value (eg 80%) is also undershot, as is the case for an oscillation is required. If it is determined in this way that - corresponding to an oscillation - an upper extreme value of the flow is followed by a lower extreme value, then it is checked whether this lower extreme value is followed by an upper extreme value and whether this subsequent upper extreme value exceeds an alarm value. steps that is a predetermined factor (eg 1.3) above the first detected extreme value. If this is the case, it is concluded after this one oscillation period that an increasing ("rising") oscillation threatens to exceed A tn , and the SCRAM is initiated before the value A-na is reached.
- a predetermined factor eg 1.3
- this prior art only provides to dampen the oscillation by rapidly retracting virtually all control rods (total SCRAM). Apart from the SCRAM, this strategy therefore does not provide any further measure for damping the oscillation and also does not reduce the probability of the SCRAM, which represents a considerable intervention in the operation of the reactor. Rather, if there is a strong oscillation, damping will only take place earlier (i.e. below instead of. This only reduces the thermal load on the fuel assemblies.
- the object of the present invention is, however, to better recognize such oscillations and to dampen the oscillation as much as possible in such a way that a SCRAM no longer has to be introduced at all, that is to say, without intervention or as little interference as possible in the reactor operation.
- the task also includes suitable, as interference-free monitoring of the critical condition as possible.
- the invention provides, by measuring the physical quantity (ie the neutron flux, insofar as it concerns the aforementioned thermo-hydraulic oscillations) to form local measured values in several areas of the reactor core, which are assigned to the respective areas.
- the current alarm level is formed by monitoring the measured values, namely the highest alarm level, the monitoring criterion of which is met by the measured values in a predetermined minimum number of ranges.
- the monitoring criterion can consist of several individual conditions, for example exceeding separate limit values for the amplitude and the rate of decay of the extreme values.
- the stabilization strategy is to insert several control rods into the core in order to reduce the reactor output (alarm stage I).
- At least two higher-level alarm levels are provided, whereby in alarm level II only a few control rods corresponding to a fraction of the total number are slowly moved into the core in such a way as corresponds to an operational reduction in performance (ie the reactor control performs an operational reduction of the output, even if, for example, a higher power consumption would require a higher reactor output and the operating personnel want to start up the reactor output).
- the second higher-level alarm level (alarm level III) - similar to a total quick shutdown of the reactor (total SCRAM) - control rods are retracted quickly, but this does not affect all but only part of the control rods (“partial SCRAM"). A total SCRAM is then no longer required, but an alarm stage IV which triggers the SCRAM can be provided as an option.
- a method for operating a reactor which is unstable due to the oscillation of a physical quantity occurring in the core also provides for a measured value to be formed by measuring the physical quantity, which detects the rate of oscillation (possibly also further measured values) ).
- a decision is made as to whether a stabilization strategy is initiated to dampen the instability or whether the reactor is initially continued to be operated after the measured values entered as a function of the operation.
- the reactor can continue to be operated at least two oscillation periods during the measurement of the decay rate, without intervening in the reactor controller, provided that no measured value does not reach a limit value provided for initiating a total SCRAM. So z. B.
- a threshold value for the extreme values of the oscillating physical variable, which is dependent on the burr is preferably specified, and the stabilization strategy is initiated when the extreme values exceed this threshold value.
- a threshold can be specified for the decay rate, the stabilization strategy being initiated when the decay rate exceeds this threshold value.
- a number of oscillation periods depending on the decay rate can be specified in order to initiate the stabilization strategy only when the oscillation of the physical quantity continues over the duration of these oscillation periods.
- stabilization strategy to be initiated is selected as a function of the decay rate.
- the invention can provide that several sensors for measuring the physical size are arranged in several areas of the reactor core, the output signals of the sensors being combined to form a number Mp of area channels and each Area channel are each assigned an area and sensors arranged therein for generating an area signal.
- the area signals are then combined into a number P of system channels, several area channels being assigned to a system channel in which they generate a system signal.
- the system signals are finally assigned to an end channel by generating an end signal.
- An alarm end signal is set in the end signal by means of monitoring stages and selection stages as soon as a monitoring criterion has been met over several oscillation periods at least in a predetermined number Np of the system channels, namely in a minimum number Nmp between area channels of this system.
- the output signal of each sensor influences at most one area signal and each area signal at most one system signal.
- the area signals of a system channel are in each case formed from the output signals from sensors which lie in areas which are distributed over the cross section of the reactor core in such a way that the area adjacent to such a th areas contain sensors whose output signals are assigned to area channels of other system channels.
- the invention can provide a device which has a system selection stage, a number P of range selection stages, a number Mp of range monitoring stages for each range selection stage and one for each range monitoring stage Contains sensor stage with a plurality of sensors arranged within a region of the core and assigned to this region monitoring stage.
- This device is designed in such a way that the sensors assigned to an area monitoring level each provide measurement signals for the physical quantity which are combined to form an area signal, and that each area signal in the area monitoring level assigned to the sensors is monitored according to a monitoring criterion, each Area monitoring stage provides an area signal containing an area monitoring signal.
- Each area monitoring signal is connected to at least one area selection stage, which forms a system monitoring signal from a predetermined minimum number of area monitoring signals. Each system monitoring signal is then fed to the system selection stage; This provides a final monitoring signal using a specified minimum number of system monitoring levels.
- the invention includes a device for monitoring the reactor state, which is unstable due to the local oscillation, in which several sensors for measuring the physical quantity are arranged in several areas of the reactor core and the output signals of several sensors of one area are combined to form an assigned area signal.
- An evaluation stage is assigned to each area signal, which identifies the occurrence of extreme values of the physical quantity in the area signal (in particular over several oscillation periods) and, in the case of an oscillation of constant frequency and corresponding duration, determines the decay rate of the extreme values in this area .
- the computing levels are assigned at least one monitoring level which sets an alarm signal, the extreme values meeting at least in a predetermined number of areas a local monitoring criterion which is dependent on the determined decay rate.
- a device for monitoring the local oscillations can contain sensors for measuring the physical quantity, which are arranged in several areas of the reactor core and the output signals of several sensors of one area are combined to form an assigned area signal.
- An evaluation stage is then assigned to each range signal, which identifies the occurrence of an oscillation of constant frequency in the range signal.
- a final monitoring level is assigned to the evaluation levels, which selects an alarm level from a hierarchy of alarm levels, in accordance with predetermined monitoring criteria for the oscillations identified in at least a predetermined number of area signals.
- the final monitoring level defines a point in time (or at least the criteria for the point in time) at which an emergency command for initiating a stabilization strategy corresponding to the alarm level is issued.
- This point in time can be predetermined, for example, by a number of oscillation periods, which waits before a stabilization measure is initiated Be 12.
- a limit value for example a limit value for the amplitude
- instantaneous actual values for example actual values of the decay rate
- FIG. 1 shows the diagram of the fuel elements and measuring lances arranged in the core of a boiling water reactor and their assignment to monitoring areas and monitoring systems
- FIG. 2 shows a measuring lance with four sensors for monitoring an area and a sensor stage assigned to these sensors in an area channel assigned to the area
- FIG. 3 shows an evaluation unit and a monitoring unit in this area channel
- FIG. 4 shows the division of the area signals generated in different areas and area channels into systems
- 5 shows a critical oscillation in the measured value of the flow and its damping in a SCRAM
- FIG. 6 shows the amplitude values of the flow that increase unimpeded with a different decay rate until the thermally hydraulic limit value A tn
- 7 shows the relationship between the rate of increase DA and until reaching a permissible maximum value A max available oscillation periods
- Figure 8 the amplitudes occurring at different Aufklingraten in the case of through a
- Figure 9 shows the course of the extreme values (amplitudes) during operation of the reactor with a relatively weak-sounding oscillation according to a preferred embodiment of the invention
- Figure 10 shows the corresponding course with a rapidly rising oscillation
- Figure 11 shows a range monitoring level at a preferred - th embodiment.
- FIG. 1 schematically shows a cross section 1 through a reactor core in which square fuel elements 2 are closely spaced in a checkerboard fashion.
- four such fuel assemblies each form a square in which one of the measuring lances labeled (1), (2) .. (28) is arranged at only one corner.
- Such a measuring lance is therefore usually arranged at the common corner of four abutting squares, each consisting of four fuel elements.
- an "area" e.g. the adjacent, differently hatched areas 2 ', 2''
- each measuring lance (position 3 in FIG. 2) each comprises four sensors 4a, 4b, 4c and 4d arranged one above the other in a cladding tube 5, four sensor signals are transmitted to the total via the corresponding measuring lines 6 of the measuring lances (1) .. (28) Device for monitoring the core supplied.
- Each of these measuring lines 6 thus carries the sensor signals assigned to an area.
- These monitoring systems work redundantly and in each case deliver their own monitoring signal and possibly an alarm signal, these signals only being processed into a final monitoring signal or final alarm signal in a system selection.
- the corresponding core-monitoring monitor therefore only contains systems that are independent of one another (no sensor signal is processed in more than one system) and the areas monitored by them do not overlap. If one measuring probe fails, a whole area of 16 fuel elements is no longer monitored, but only one of the redundant systems is affected, while the other systems are not affected by this failure. Sensors of neighboring areas are always assigned to different systems. These principles are also retained in other configurations of the core (e.g. larger cores) and the measuring lances (e.g. 34 instead of 28 measuring lances).
- all areas each acquire an equal number (namely four) sensor signals, while in the general case the number of sensor signals can also be different for the individual areas. This can be provided above all if the "linear" assignment specified above, in which each sensor is assigned to at most one individual system, is not carried out.
- Each sensor signal is first subjected to a plausibility check in its area channel by means of a selection stage 8, sensor signals which are outside the proper working range of the sensors being initially eliminated, as also mentioned in the above
- EP-A-0 496 551 is provided.
- only a minimum number (here: two) is selected from the remaining output signals of properly working sensors, as a rule the signals of the lowest available sensors.
- the signals from sensors arranged one above the other differ only slightly and, in particular, they show the same temporal profiles due to the local power pulsation in this area, practically without phase shift. In principle, the sensors can therefore replace each other.
- taking the lowest sensors (4a and 4a in FIG. 2) into account offers a slight advantage, since in the critical area of high power and low coolant throughput, the flow in the lower areas of the fuel assemblies causes more pronounced oscillations than in the upper areas, i.e. the corresponding extreme values (amplitudes) of the oscillation can be detected more clearly.
- this selection stage 8 fed by the sensor signals, can be preceded by an analog filter 9 'for the sensor signals, the selection of the two sensor signals released for further processing by a "2 out of 4" selection 10 ("2 out of 4" ) can take place, which can simultaneously convert the analog input signals into digital output signals, so that instead of the upstream analog filter 9 ', a digital filter 9 can also be connected.
- this filter 9 also performs a sum of the two output signals of the selection stage 8 in order to obtain an instantaneous value for the flow into the corresponding region, averaged over the sample scatter of the individual sensors. This corresponds to the sum tion of the sensor signals in the individual "cells" of the mentioned EP-A-0 496 551, although in this prior art the corresponding "cell signal” is formed by sensor signals, which are also used for monitoring other areas and in other systems become.
- a current measurement value A (t) -A * is then formed in a standardization unit from the current signal A (t) at the output of the filter 9, which e.g. can be normalized to the average signal level A * of this range.
- this average level can be formed by an integrator 10 by integrating the signal A (t) detected over a relatively long integration period.
- This normalization provides an alternating positive and negative measured value, so that the oscillation amplitudes are symmetrical about a zero point and are easy to detect.
- digital signal processing also enables the amplitude of a half-period to be detected without great effort, even in the case of differently standardized or non-standardized signals S, in which case it can be advantageous that limit values can be specified as absolute values instead of relative values.
- the area channel of a system p contains an evaluation stage 12, in which the time T n is initially recorded in a first calculation stage, at which a signal value S which initially rises and is above the noise limit Ao has risen to an extreme value A n and drops again (positive peak).
- a signal value S which initially rises and is above the noise limit Ao has risen to an extreme value A n and drops again (positive peak).
- - or preferably additionally - Peak A n and its time T n also become negative Peak detected, ie an extreme value lying beyond the noise limit Ao, which is formed by an initially decreasing, then increasing (negative) value of the signal S.
- This extreme value detection 13 is followed by a further plausibility monitor 14, which is designed, for example, as described in EP-A-0 496 551 and checks whether the time interval DT n that can be detected in the extreme value monitor 13 is between currently recorded time T n and the previously recorded time T n can correspond to an oscillation which lies between 0.3 and 0.7 Hz within the critical frequency band.
- Another evaluation element 15 checks vor ⁇ part by way of addition, whether the detected time interval DT n with the last detected time interval DT n _ practically coincide. If this is not the case, then the peaks recorded are not the amplitudes of an oscillation which is practically not damped and could rise to dangerous extreme values; the further evaluation of the last peak A n determined is then suppressed.
- a monitoring element 18 now forms a signal according to predetermined monitoring criteria described in more detail below, which indicates, for example as a binary signal in the state "0", that there is no dangerous oscillation corresponding to the monitoring criteria while the state "1" of the corresponding monitoring signal triggers an alarm (position 19).
- This The alarm signal together with other information which, for example, identify the area in which the monitoring criterion has addressed, can be output to a display unit and / or stored in a memory for documenting the process.
- the linear alarm area signals represent an M p -fold binary signal corresponding to the number p of area channels, from which an N m p-fold binary signal is formed in an area selection stage 20, to indicate that a bit corresponding to an alarm has been set in at least a number N m p of areas of this system.
- a corresponding alarm bit should only be set in the area signal when the monitoring criterion is met in at least two areas of the system in order to rule out a false alarm due to processing errors.
- a system selection is now made in an output stage 24, which in each case sets an alarm end signal when the total number P of systems contains at least a minimum number Np of a set alarm signal.
- the processing elements of the area channel shown in FIGS. 2 and 3 can be implemented in any system by a central computer with its own power supply, a central processor unit, an input module for 32 analog input signals and a corresponding output module for 32 digital output signals - the one that is approximately 50% full at a working frequency of 32 MHz with the parallel processing of the 28 sensor signals contained in the 32-bit input of the computer.
- An advantageous sampling rate for the input signals is 50 Hz or more, but at least 20 Hz.
- the usual processing elements for the sensor signals offer sufficient space for the processor units of the systems.
- the output signals of these system processors can be connected to a commercially available microcomputer in which the received area signals are processed and stored.
- This processor also contains the programs which are necessary in order to make the system selection and to deliver the signals according to predetermined strategies which are required in the reactor control for carrying out the respective stabilization measures.
- Glass fibers can advantageously be used as connecting lines.
- the curve 30 of FIG. 6 corresponds to the extreme case represented by curve 30 in FIG. 5, further curves 34, 33, 32 and 31 being indicated in this FIG. 6, the rate of which DA increases by a factor of 1/2, 1 / 3, 1/4 and 1/5 are lower. It can be seen from FIG. 6 that at these decay rates, a SCRAM which would be triggered if the limit value A max was exceeded is not required, but rather the time or number N 'of the oscillation periods DT required for the effectiveness of the SCRAM allows the reactor to continue operating a certain number N of periods which result from the intersection of curves 32, 33 .. with curve F (A4).
- FIG. 5 shows the relationship between the decay rates DA and the period N given by the curve F (A4), which are still available after the limit value A ⁇ ⁇ x has been exceeded before a SCRAM is initiated, as a corresponding limit curve F ( DA) reproduced.
- a curve can be determined - taking into account a sufficient safety reserve - from model calculations for the behavior of the reactor in transient states and from the comparison of such model calculations with actually observed reactor states and can be stored, for example, as a characteristic curve in a memory.
- the limit value A] _i m is exceeded, it is then sufficient to use the respective detected rate of decay in order to obtain the corresponding value N (for the curves 31, 32, 33, 34, the values N1, N2, N3, N4) refer to.
- a counter can then be set to the corresponding value N, which is counted down with each confirmation signal "confirmation" (FIG. 3).
- the reactor operation then does not need to be interrupted by a total SCRAM as long as the counter reading has not been counted down to zero. Even then, the total SCRAM does not need to be introduced until the amplitude limit value A4 has been reached.
- the oscillation is automatically dampened and subsides again within this time, which can be ensured in particular if an alarm signal is set when the limit value A j - ⁇ x is exceeded, which only prevents at this alarm level that changes in the operating state are made in the control which could lead to an increase in output and thus to a further transient excitation of the oscillation.
- a stabilization strategy followed, which corresponds to a low-level alarm level and does not require an interruption of the reactor operation, in particular no SCRAM, as long as it is not exceeded by the 7 curve and / or exceeding the limit value A4 there is a high-level alarm level with a total SCRAM.
- the duration for this reactor operation can be limited to a number N3 of reactor periods, whereby to improve the damping, provision can also be made for a part of the control rods to be slowly moved into the reactor, which corresponds to a reduction in the reactor output. as is intended for operational purposes when the reactor is required to have a lower capacity.
- the limit values DA3 and DA4 for the decay rate determine an alarm stage III, in which the reactor can continue to run a number N4 of periads, it also being possible to quickly retract some of the absorber rods here (as "partial SCRAM "). Only when the limit value DA4 is exceeded does a total SCRAM then appear in a high-level alarm stage.
- FIGS. 8 to 10 Another variant of the invention is explained with reference to FIGS. 8 to 10.
- Figure 8 are for the amplitudes of the relative range signal S shows decay rates which correspond to curves 32 and 33 in FIG. These amplitudes are determined at the point in time at which they exceed the limit A lim. It is assumed that the alarm level II was detected by the monitoring level and a stabilization strategy was initiated, in which the reactor power is to be stabilized by slowly retracting the control rods. In the case of curve 33, the amplitudes occurring under these conditions are indicated by solid lines.
- the stabilization strategy corresponding to alarm level II would - if it were also maintained at amplitude values that lie above a limit value indicated by A3 and is represented by peaks shown in broken lines - would mean that a total SCRAM would have to be initiated with the limit value A4 . Such a total SCRAM should, however, be avoided. Therefore, when the limit A3 is reached, the stabilization strategy (slow retraction of absorber elements) discussed in connection with alarm stage II in FIG. 7 is switched to a higher alarm stage with a higher-ranking stabilization strategy, namely the "partial SCRAM" mentioned. As a result, the oscillation is now dampened to a greater extent, so that the amplitudes do not continue to increase, ie the limit value A4 is not reached and the total SCRAM is not initiated.
- Curve 32 shows that in this case too, the limit A3 can be set higher at a lower decay rate than at a higher decay rate.
- the decay rate is not monitored for exceeding limit values; rather, the currently detected decay rate is used to specify a limit value for the amplitude values themselves.
- the dependence of the limit value on the decay rate can in turn be determined on the basis of a calibration curve, similar to FIG. 7, or it can also be broken down into a corresponding division of the area available for the decay rate Alarm levels, the corresponding limit value A3 can be changed in stages.
- This variant has the advantage that changes in the decay rate, which occur during reactor operation even after the limit value A-Hm has been exceeded, are particularly taken into account. This is shown in curve 40 of FIG. 8, in which it is initially assumed that the oscillation increases so weakly when the limit value Aii m is exceeded that intervention in the reactor control system is not necessary. However, it is assumed that the operating personnel at time t D increased the output via the operational reactor control system, which considerably increases the transiently excited oscillation.
- the curve 42 shown in FIG. 10 is based on a relatively high ringing rate DA, which is why the limit values AI, A2 and A3 in this case - depending on the dedicated ringing rate DA - are set lower than in FIG. 9. Therefore, the alarm level II (Limit value A2) is reached relatively early and the "partial SCRAM" provided by exceeding limit value A3 in alarm level III is also carried out earlier. This leads to the desired damping of the oscillation and prevents the limit value A jrt ax from being exceeded. This prevents a total shutdown even in this unfavorable case.
- the respective alarm levels can be reset, for example, when the amplitude exceeds the limit value falls below again.
- FIG. 11 shows an embodiment for the monitoring in the command channels of the system 1, the area selection stage for the alarm signals which are set in the area signal by this monitoring, and the monitoring device in the corresponding system channel.
- the area monitoring in the first area of channel 1 is shown in the fields labeled "Region 1", the area signal assigned to this first area corresponding to the limit value AI being fed to a limit value detector which sets a logical alarm signal "1" when the range signal S exceeds the limit value AI.
- This limit value is taken from a memory 52 for a characteristic curve. According to the stored characteristic curve, this limit value AI corresponds to the value DA of the current decay rate determined in area channel 1 (position 16, FIG. 3).
- the logic output signal of the limit value detector 51 can be used to control a display and / or memory unit 53, which now forms an alarm area signal AA1 assigned to the first alarm level for the monitoring signal AA1, which is assigned to the first alarm level and the first area channel.
- the relative range signal S is measured in an evaluation unit 54 (not shown in more detail) with regard to the limit value A2 and a monitoring stage containing the limit value detector 55, the characteristic curve memory 56 and the display and / or memory unit 57 with regard to the limit value A3 and of alarm level III. It is not shown that the signal S can be monitored by means of a further limit value detector for exceeding a predetermined limit value A4.
- the monitoring signals formed by the limit value detectors 51, 51 'in the individual range channels can be summed in a summing element 60.
- This signal thus indicates the number of range channels in which the corresponding limit value detector 51 has set an alarm signal of stage I. If this number is greater than or equal to a predetermined number Nmp, a corresponding interrogation unit 61 sets a corresponding alarm system signal. In this case, the interrogation unit 61 carries out this interrogation twice, the minimum number Nmp being set to 1 for a first alarm system signal AAl ".
- this signal can be used to form an alarm end signal from all the alarm signals that are generated in the redundantly operating systems, which can intervene in the control of the reactor and block an operational increase in the reactor output there .
- the system selection forms only a "1 out of 4" selection, that is to say the corresponding signals AA1 1 'of the four systems are combined by an "OR" element.
- a minimum number Np for the system signals in which the Alarm level I is set can be done in a simple manner by adding the logical signals AA1 ′′ of the systems and generating the intervention in the reactor control only if the sum is greater than or equal to 2.
- the summing elements 62, 64 can be used to process the monitoring signals of the individual areas of the system assigned to alarm levels II and III into corresponding signals, which are generated in interrogation units 65, 66 to generate the alarm system signals AA3 'and AA3' assigned to these levels. ' deliver.
- the alarm signals AA2 ′′ of the four system signals are processed further (not shown) in the same way that was described on the basis of signals AAl ′ 1 and form an alarm end signal assigned to this alarm stage II, which is thus assigned to the Reactor operation intervenes that not only blocks a start-up of the reactor power, but even the reactor power after the pro programs that are intended for normal reactor operation are shut down.
- the alarm signals AA3 '' assigned to alarm level III are further processed and form an alarm end signal assigned to this alarm level III which, according to the stabilization strategy assigned to this alarm level, partial SCRAM ".
- the alarm signals formed by means of the fixed limit value A4 are further processed in the same way in order to trigger a total SCRAM corresponding to the highest alarm level if necessary.
- the invention thus ensures on the one hand that the unstable state of the reactor is monitored with sufficient redundancy in order to be able to make a reliable statement about the unstable state in the event of failure of individual sensors, measuring lances or computing elements, and on the other hand that damping is also achieved the instability is only affected to a small extent in the reactor operation.
- a total SCRAM is practically excluded according to all experience and estimates, so that the fourth alarm level, the strategy of which provides for a total SCRAM, can be regarded as completely superfluous.
- the components provided for monitoring the limit value A- f ⁇ x and the transmission elements for an alarm signal assigned to this highest alarm level are therefore only described as an option, which can also be dispensed with.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP98123358A EP0928007B1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19500395 | 1995-01-09 | ||
DE19500395A DE19500395A1 (de) | 1995-01-09 | 1995-01-09 | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand |
PCT/DE1996/000014 WO1996021929A1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und vorrichtung zum betrieb eines reaktors im instabilen zustand |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98123358A Division EP0928007B1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0803125A1 true EP0803125A1 (de) | 1997-10-29 |
Family
ID=7751150
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP96900255A Ceased EP0803125A1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und vorrichtung zum betrieb eines reaktors im instabilen zustand |
EP98123358A Expired - Lifetime EP0928007B1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP98123358A Expired - Lifetime EP0928007B1 (de) | 1995-01-09 | 1996-01-08 | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand |
Country Status (6)
Country | Link |
---|---|
US (3) | US5875221A (de) |
EP (2) | EP0803125A1 (de) |
JP (3) | JP4063867B2 (de) |
DE (2) | DE19500395A1 (de) |
ES (1) | ES2206814T3 (de) |
WO (1) | WO1996021929A1 (de) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5528639A (en) † | 1994-08-01 | 1996-06-18 | General Electric Company | Enhanced transient overpower protection system |
WO1999056285A1 (de) * | 1998-04-28 | 1999-11-04 | Siemens Aktiengesellschaft | Verfahren und vorrichtung zur überwachung des leistungsanstiegs beim anfahren eines kernreaktors (diversitäre exkursionsüberwachung) |
CN1158672C (zh) * | 1998-08-25 | 2004-07-21 | 东芝株式会社 | 核反应堆固定式堆内核测量仪表系统 |
DE10159432A1 (de) * | 2001-12-04 | 2003-06-26 | Framatome Anp Gmbh | Steuerungssystem für eine Kernkraftwerksanlage sowie Verfahren zum Betreiben einer Kernkraftwerksanlage |
US8135106B2 (en) * | 2004-04-23 | 2012-03-13 | Areva Np Inc. | Protection of reactor cores from unstable density wave oscillations |
DE102005058192A1 (de) * | 2005-12-06 | 2007-06-28 | Airbus Deutschland Gmbh | Vorrichtung zur Fehlererkennung von verstellbaren Klappen |
JP2007240464A (ja) * | 2006-03-10 | 2007-09-20 | Toshiba Corp | 沸騰水型原子炉炉心状態監視装置 |
CN101840740B (zh) * | 2009-06-19 | 2012-10-03 | 中广核工程有限公司 | 一种两通道故障自动检测系统及检测方法 |
US9177676B2 (en) | 2010-05-14 | 2015-11-03 | Kabushiki Kaisha Toshiba | Nuclear reactor power monitor |
EP2581914B1 (de) * | 2011-10-10 | 2014-12-31 | Ion Beam Applications S.A. | Verfahren und Anlage für die Herstellung eines Radioisotops |
CN105161143A (zh) * | 2014-05-29 | 2015-12-16 | 江苏核电有限公司 | 一种反应堆物理启动期间增效节能的综合方法 |
US11227697B2 (en) * | 2018-10-29 | 2022-01-18 | Framatome Inc. | Self-powered in-core detector arrangement for measuring flux in a nuclear reactor core |
CN110428919B (zh) * | 2019-07-08 | 2023-01-17 | 中国核电工程有限公司 | 基于征兆的压水堆核电厂反应性控制策略的设计方法 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DD132457A1 (de) * | 1977-08-01 | 1978-09-27 | Klaus Meyer | Verfahren zur ueberwachung von schwingungen von spaltzonenelementen in kernreaktoren |
JPS59196499A (ja) * | 1983-04-22 | 1984-11-07 | 日本原子力事業株式会社 | 沸騰水型原子炉の炉心安定性監視方法 |
JPS60159691A (ja) * | 1984-01-31 | 1985-08-21 | 株式会社東芝 | 原子炉運転制御装置 |
JPS6275295A (ja) * | 1985-09-28 | 1987-04-07 | 株式会社東芝 | 原子炉の局所振動監視装置 |
US5174946A (en) * | 1991-01-22 | 1992-12-29 | General Electric Company | Oscillation power monitoring system and method for nuclear reactors |
US5141710A (en) * | 1991-06-24 | 1992-08-25 | General Electric Company | Reactivity modulation of a boiling water reactor to stabilize thermal-hydraulic instabilities |
US5225149A (en) * | 1991-09-30 | 1993-07-06 | Combustion Engineering, Inc. | Detection of core thermal hydraulic oscillations |
JP2838002B2 (ja) * | 1992-09-11 | 1998-12-16 | 日本原子力研究所 | 原子炉出力の不安定性監視方法 |
JPH06201884A (ja) * | 1992-09-22 | 1994-07-22 | Toshiba Corp | 原子炉出力監視装置 |
-
1995
- 1995-01-09 DE DE19500395A patent/DE19500395A1/de not_active Withdrawn
-
1996
- 1996-01-08 EP EP96900255A patent/EP0803125A1/de not_active Ceased
- 1996-01-08 WO PCT/DE1996/000014 patent/WO1996021929A1/de not_active Application Discontinuation
- 1996-01-08 EP EP98123358A patent/EP0928007B1/de not_active Expired - Lifetime
- 1996-01-08 DE DE59610767T patent/DE59610767D1/de not_active Expired - Lifetime
- 1996-01-08 ES ES98123358T patent/ES2206814T3/es not_active Expired - Lifetime
- 1996-01-08 JP JP52136496A patent/JP4063867B2/ja not_active Expired - Lifetime
-
1997
- 1997-07-09 US US08/890,258 patent/US5875221A/en not_active Expired - Lifetime
-
1998
- 1998-11-04 US US09/185,848 patent/US5978429A/en not_active Expired - Lifetime
- 1998-11-04 US US09/186,000 patent/US6122339A/en not_active Expired - Lifetime
-
2005
- 2005-05-23 JP JP2005149151A patent/JP4252048B2/ja not_active Expired - Fee Related
- 2005-05-23 JP JP2005149150A patent/JP4361035B2/ja not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO9621929A1 * |
Also Published As
Publication number | Publication date |
---|---|
US5875221A (en) | 1999-02-23 |
EP0928007A1 (de) | 1999-07-07 |
JP4361035B2 (ja) | 2009-11-11 |
US5978429A (en) | 1999-11-02 |
WO1996021929A1 (de) | 1996-07-18 |
JP4063867B2 (ja) | 2008-03-19 |
DE19500395A1 (de) | 1996-07-18 |
DE59610767D1 (de) | 2003-11-13 |
JP2005241657A (ja) | 2005-09-08 |
EP0928007B1 (de) | 2003-10-08 |
JPH10512051A (ja) | 1998-11-17 |
JP4252048B2 (ja) | 2009-04-08 |
ES2206814T3 (es) | 2004-05-16 |
JP2005283597A (ja) | 2005-10-13 |
US6122339A (en) | 2000-09-19 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0928007B1 (de) | Verfahren und Vorrichtung zum Betrieb eines Reaktors im instabilen Zustand | |
DE69720950T2 (de) | Verfahren zur Steuerung einer Kraftwerksanlage | |
DE2714069A1 (de) | Verfahren und einrichtung zum feststellen und analysieren von fehlerquellen | |
DE3507344C2 (de) | ||
DE2941544C2 (de) | Regeleinrichtung für den Flüssigkeitsstand in einem Kernreaktorbehälter | |
DE2531396C3 (de) | Anordnung zur Regelung der Ausgangsleistung eines Siedewasserkernreaktors | |
DE2827442A1 (de) | Verfahren zur steuerung von reaktivitaetswirkungen aufgrund leistungsaenderung in druckwasser-kernreaktoren | |
DE102018116446A1 (de) | Windenergiesystem und Verfahren zum Erkennen niederfrequenter Schwingungen in einem elektrischen Versorgungsnetz | |
DE1474032A1 (de) | Geraet zur Programmunterbrechung und zur Ausloesung eines Unterprogramms in einem digitalen Prozessrechner | |
DE4412024A1 (de) | Solarkollektor mit Störungsüberwachung | |
DE2337354C3 (de) | Vorrichtung zur Regelung eines Druckwasserreaktors mit verstellbaren Steuerstäben | |
EP1075696B1 (de) | Verfahren und vorrichtung zur überwachung des leistungsanstiegs beim anfahren eines kernreaktors (diversitäre exkursionsüberwachung) | |
EP2915998A1 (de) | Verfahren zum Betrieb einer Windenergieanlage | |
CH638919A5 (de) | Verfahren zur ueberwachung der lokalen leistungsdichte in kernreaktoren. | |
EP1595264B1 (de) | Verfahren zur messung einer relativen grösse des abbrandes von brennelementen eines kugelhaufen-hochtemperaturreaktors (htr) sowie dazu geeignete vorrichtung | |
EP1208569B1 (de) | Verfahren zur entnahme abgebrannter brennelemente aus einem kugelhaufen-hochtemperaturreaktor | |
DE2434528C3 (de) | Kernkraftwerksanlage | |
DE3149536A1 (de) | Hochtemperaturreaktor mit einem kern aus kugelfoermigen brennelementen | |
DE2624321C2 (de) | Verfahren und Vorrichtung zum Kontrollieren der Funktionsfähigkeit eines in einer Sicherheitsanordnung enthaltenen Meßkanals | |
DE202020002815U1 (de) | Nukleare Hauptpumpe mit einer Überdrehzahl-Schutzvorrichtung | |
CH634943A5 (en) | Gas-cooled graphite-moderated nuclear reactor having two mutually independent shutdown systems | |
DE10159432A1 (de) | Steuerungssystem für eine Kernkraftwerksanlage sowie Verfahren zum Betreiben einer Kernkraftwerksanlage | |
DE19945172B4 (de) | Vorrichtung und Verfahren zum Überwachen der Reaktorleistung eines Reaktors zur Zeit von dessen Inbetriebnahme | |
DE2461389A1 (de) | Verfahren fuer den betrieb von kernreaktoren | |
AT525894A4 (de) | Kontrollverfahren für eine Kontrolle eines Ist-Anodeneingangsdrucks in einem Anodenzuführabschnitt für einen Anodenabschnitt eines Brennstoffzellensystems |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19970703 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): CH DE ES LI SE |
|
17Q | First examination report despatched |
Effective date: 19981119 |
|
APAB | Appeal dossier modified |
Free format text: ORIGINAL CODE: EPIDOS NOAPE |
|
APAD | Appeal reference recorded |
Free format text: ORIGINAL CODE: EPIDOS REFNE |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: FRAMATOME ANP GMBH |
|
APBX | Invitation to file observations in appeal sent |
Free format text: ORIGINAL CODE: EPIDOSNOBA2E |
|
APBT | Appeal procedure closed |
Free format text: ORIGINAL CODE: EPIDOSNNOA9E |
|
APBT | Appeal procedure closed |
Free format text: ORIGINAL CODE: EPIDOSNNOA9E |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN REFUSED |
|
18R | Application refused |
Effective date: 20040819 |
|
APAF | Appeal reference modified |
Free format text: ORIGINAL CODE: EPIDOSCREFNE |