Background technology
Pressurized-water reactor nuclear power plant mainly is made up of three parts such as pressurized water reactor, a circuit system and secondary coolant circuit system.Nuclear fission is to enter ground in the reactor core of being made up of nuclear fuel in pressure vessel.Presurized water reactor is that fuel, light-water are cooling medium and moderator with the low-enrichment uranium.The nuclear fission liberated heat take out-pile out of by the water under high pressure of a circuit system in the heap of flowing through and in steamer generator with the water of heat transferred secondary circuit.The steam that produces after water is heated promotes steam turbine, and steam turbine then drives generator for electricity generation.The fuel assembly that loads in the reactor core is made up of fuel rod one by one.In case when cut appears in the water under high pressure of a circuit system, will cause loss of-coolant accident (LOCA).If when at this moment the normal moisturizing ability in a loop can not remedy the cooling medium of leakage, the nuclear fuel in the reactor core can not in time cool off, and may cause fuel can to burn because of overheated, even the accident that causes dioxy gasification uranium pellet to melt.For this reason, also be provided with the security system of special reply dehydration and so on accident in nuclear power station, generally speaking, it comprises safety injection system and the containment spray system that injects boron water to reactor.
As shown in Figure 1, safety injection system generally comprises material-changing water tank 1, volume control tank 2, high-pressure safety injection pump 5, low pressure safety injection pump 3, dense boron injection tank 6, diesel engine, electrodynamic pump etc., material-changing water tank 1 passes through low pressure safety injection pump 3 and high-pressure safety injection pump 5 respectively to a loop 9 water fillings, volume control tank 2 is connected with high-pressure safety injection pump 5, be connected by high-pressure safety injection pump 5 supercharging pipeline isolation valves 4 between low pressure safety injection pump 3 and the high-pressure safety injection pump 5, high-pressure safety injection pump 5 has also connected the isolation valve 51 of high-pressure safety injection pump 5 recirculation lines, dense boron injection tank 6 is arranged on the pipeline between a high-pressure safety injection pump 5 and the loop 9, is respectively equipped with advancing of dense boron injection tank 6 at the two ends of this dense boron injection tank 6, outlet isolation valve 61,62.
As shown in Figure 2, containment spray system mainly comprises elements such as material-changing water tank 1, spray pump 7, alkali jar 8, material-changing water tank 1 is connected with spray pump 7, spray pump 7 is with the pressurization of the water in the material-changing water tank 1 back output, be used for the space environment in the whole containment is cooled off, and alkali jar 8 is the NaOH that is filled with high concentration, it is connected on the loop of material-changing water tank 1 and spray pump 7 formation by an alkali jar 8 outlet isolation valves 81, when the radioiodine leakage occurring, NaOH can enter the spray loop radioiodine in the containment atmosphere is absorbed by chemical reaction.In case normal cooling system has lost effect, safety injection system and containment spray system will be devoted oneself to work, to guarantee the safety of nuclear power station.
The unloading phase of the debugging of nuclear power station, need control switchboard in a large number to the power station and carry out power-fail experiment, be called for short the COC test.This is that of debug phase is large-scale, complexity and excessive risk test, and its purpose will have following: unit behavior after the dead electricity of checking design hypothesis; Checking switchboard dead electricity accident operating standard; Make the operations staff be familiar with such accident.Owing to when controlling the switchboard power-fail experiment, the very risky of error safety injection and spray action occur, in case carried out peace notes and spray action, will bring the follow-up work of large amount of complex, even also need to change some equipment, this is that test institute is unacceptable.Therefore, should effectively prevent, guarantee the security level of unit again, but can't normally carry out when unlikely appearance really needs peace to annotate and spray error safety injection and spray action.To this, prior art provides the method for a kind of anti-error safety injection and spray, promptly extracts RPR (reactor protection system) fastener before control switchboard power-fail experiment.After extracting fastener, pacify notes, spray and main feed water by-pass automatically and close unavailablely, only keep manually that peace is annotated, spray is available.After test is finished, turn back to fastener again, and related RPR protection is verified comprehensively once to fastener.
This method is feasible in the heat examination stage, because during the heat examination, most of topworks power supply can be pulled out, thereby effectively error safety injection and spray be prevented.But before starting hot critical first (hot shutdown), reactor has been equipped with nuclear fuel, and compares during the heat examination, bigger variation has taken place in situation, make in this way and need in the RPR rack, extract the anti-peace of " Y " output card and annotate, extract the anti-spray of " V " output card.This can bring following problem: at first, because peace is annotated and is sprayed and all is in down state automatically, in case when so really needing peace to annotate, to rely on manually fully and start, and require the long and operator of value on duty to judge in the short time and make a strategic decision at the utmost point is suitable difficulty, obviously can bring certain influence to what the peace of needs was annotated and sprayed; Secondly, after test is finished, need carry out topworks's test of the RPR of large amount of complex, action is annotated and sprayed to peace identify that again this approximately needs two day time, and want a large amount of equipment of start and stop, workload is very big.
Embodiment
In order to make technical matters to be solved by this invention, technical scheme and beneficial effect clearer,, the present invention is further elaborated below in conjunction with drawings and Examples.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
After having carried out a large amount of COC test in the heat examination stage of nuclear power station unit, owing to fail to draw immediately test findings after the off-test, for not influencing debugging startup plan, unit debugging progress continues forward impelling, on one side Analysis for CO C test figure.Before starting hot critical first (hot shutdown), after all test figures were analyzed, debugging team thought and need reform to underproof portion C OC test in the heat examination.
Yet be equipped with nuclear fuel in the reactor this moment, is different from the hot examination stage fully, the conventional practice that most of topworks power supply is pulled out.Just can not implement again.But the risk of error safety injection and spray action exists really, and very big.If according to the method for prior art, in the RPR rack, extract the anti-peace of " Y " output card and annotate, extract the anti-spray of " V " output card.Like this, extract fastener after, pacify automatically notes and spray and main feed water by-pass close unavailable, but manually peace annotate and spray still available.After test is finished, turn back to fastener, also need carry out about 30 routine tests, this approximately needs two day time, and the large number quipments start and stop will be arranged, and workload is too big.
Thinking of the present invention is, under the situation of the security level of validity that does not influence test and unit, avoid as far as possible because the subsequent treatment of the complexity that error safety injection and spray action bring by the operation quarantine measures, thereby get method for the original RPR of extracting fastener.
Concrete, with reference to figure 1 and Fig. 2, peace is annotated and spray mainly comprises following action:
1, low pressure safety injection pump 3 starts.Because of a loop 9 pressure are 154 crust safety injection pump top hole pressures, be higher than low pressure safety injection pump 3 top hole pressures far away, 3 of low pressure safety injection pumps carry out the low discharge operation, and therefore, this action can't bring complicated subsequent treatment, is acceptable.
2, second high-pressure safety injection pump 5 starts.Because formerly moved one, as long as dense boron injection tank 6 does not inject a loop 9, this action just makes fills and axle seals a flow and increases, and can accept.
3, the dense boron water of dense boron injection tank 6 injects a loop 9.This action may make voltage stabilizer be full of, and a loop 9 pressure are out of control, simultaneously a loop 9 pipelines is produced thermal shock, and makes a loop 9 boron concentration rising 300ppm, can cause complicated subsequent treatment, is unacceptable therefore.
4, diesel engine starting.As long as in time stop transport, there is no harm, can accept.
5, auxiliary water supply electric pump starts.Auxiliary feedwater is original just in operation, so did not influence, can accept.
6, main feedwater is isolated.Originally steam generation gas is supplied water by auxiliary feedwater, and did not influence can be accepted.
7, the relevant ventilation starts.Do not bring any risk, can accept.
8, spray starts.Equipment and room in the reactor building will all clean, clean, and armamentarium will overhaul, equipment component will be changed, and this is an acceptable anything but.
9, alkali jar 8 is imported high-concentration sodium hydroxide in the spray loop, the aftertreatment complexity, but because of the isolation of spray pump 7 makes the possibility of its generation extremely low, can accept.
According to aforesaid invention thinking, we only need quarantine measures are taked in unacceptable action, promptly isolate peace at duration of test and annotate dense boron injection tank 6 and spray pump 7.Like this, even error safety injection takes place, can not produce complicated subsequent treatment work yet; If annotate, only need to remove immediately the isolation of pacifying relevant devices such as annotating dense boron injection tank 6 and spray pump 7, then by relevant accident programmed control unit and really need to pacify.In addition, though the risk that the action of alkali jar 8 input high-concentration sodium hydroxide in the spray loop brings is not high, because it is very simple to get rid of the needed measure of appearance of this action, without any spinoff, therefore, in concrete operations, can also consider alkali jar 8 outlet isolation valves 81 cut out.
Under this invention thinking, a kind of anti-error safety injection method of power-fail experiment of control switchboard of nuclear power stations is provided, before the nuclear power station unit is controlled the switchboard power-fail experiment, dense boron injection tank 6 in the safety injection system and the spray pump in the spray system 7 implemented the interim isolation that can remove at any time, releasing is implemented in this isolations in the test back that finishes.Adopt such method, can carry out normal power-fail experiment, complicated subsequent treatment work can not occur after test finishes, significantly reduced the loss of workload and equipment control switchboard of nuclear power stations.Even error safety injection and spray have occurred,, and can not cause serious consequence because dense boron injection tank 6 and spray pump 7 isolated.In addition, in case the situation of notes occurs really needing to pacify, peace is annotated and the spray action still can start automatically, value length and operator carry out shirtsleeve operation and promptly can remove quarantine measures immediately, implementing normal peace annotates and spray, guarantee the requirement of nuclear safety, therefore, this method can also further improve reliability.
Described isolation may further comprise the steps, and closes the import and export isolation valve 61,62 of dense boron injection tank 6 and cuts off the power supply of spray pump 7.Step is as follows more specifically:
1) the import isolation valve 61 of dense boron injection tank 6 cuts out, cuts off the power supply, locks;
2) the outlet isolation valve 62 of dense boron injection tank 6 cuts out, cuts off the power supply, locks;
3) cut off the power supply of spray pump 7 and locking.
After dense boron injection tank 6 is isolated, can cause the flow in the high-pressure safety injection pump 5 low excessively, thereby the danger of this high-pressure safety injection pump 5 of infringement appears, therefore, from safety perspective, in aforementioned partition method, also can comprise the isolation valve 51 of step 4) unlatching safety injection system mesohigh safety injection pump 5 recirculation lines and the high-pressure safety injection pump 5 supercharging pipeline isolation valves 4 that step 5) is closed.
Concrete, the isolation valve 51 of aforementioned recirculation line and high-pressure safety injection pump 5 supercharging pipeline isolation valves 4 are electronic isolation valve, work such as also can cut off the power supply after the unlatching, lock.As a kind of preferred version, step 4) can be in step 1) and step 2) implement before, security will be higher like this.Though after closing spray pump 7, alkali jar 8 in the spray system has lost the power to spray loop output high-concentration sodium hydroxide, but in order further to improve security, isolate and also comprise step 6), promptly close alkali jar 8 outlet valves in the spray system, so just avoided high-concentration sodium hydroxide to enter the loaded down with trivial details subsequent treatment of bringing behind the spray loop fully.In the present embodiment, alkali jar 8 outlet valves are pneumatic isolation valve, can also lock after closing.
Concrete, the releasing in this method may further comprise the steps:
1) electronic isolation valve 61 releases of the import of dense boron injection tank 6 send electricity to keep closing;
2) electronic isolation valve 62 releases of the outlet of dense boron injection tank 6 send electricity to keep closing;
3) electronic isolation valve 51 releases of high-pressure safety injection pump 5 recirculation lines send electricity to be held open;
4) electronic isolation valve 4 releases of high-pressure safety injection pump 5 supercharging pipelines send electricity to keep closing;
5) power supply of spray pump 7 send;
6) the outlet isolation valve 81 of alkali jar 8 is opened in release.
As a kind of preferred version, step 3) is in step 1) and step 2) implement afterwards.In addition,, also there are wrong peace notes in the system, spray signal, do not process direct enforcement and remove, obviously can cause peace to annotate and spray and move, also will produce a large amount of unacceptable subsequent treatment if before implementing releasing work.Therefore, before implementing described releasing, also can comprise the step of checking and remove error safety injection, spray signal, so just can make that the security of this method is higher.
In addition, when implementing this method, notice that the dense boron injection tank 6 and the spray pump 7 of being isolated mustn't have other work temporarily, must guarantee that they can remove isolation at any time and put into operation.Isolate between implementation period at anti-error safety injection and spray, just in case peace is annotated automatic the startup, the reactor operator carries out peace immediately and annotates startup reactor operator operation sheet automatically, the long long operation sheet of the peace automatic startup value of notes of carrying out immediately of value.
In order to prove the validity of this method, perform sufficient supporting preliminary work after, we implement the COC test with debug machine component two days, implement twice isolation altogether.Though COC test is very risky, the unit temperature, pressure is all controlled finely in the process of the test, during peace also takes place annotates.Implement at every turn and remove anti-error safety injection to be no more than half an hour, save about two days of duration with the spray isolation cumulative time.Easy through the work of evidence this method, do not influence the validity of test.Can reduce a large amount of follow-up works, not reduce the security level of unit again.
The above only is preferred embodiment of the present invention, not in order to restriction the present invention, all any modifications of being done within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.