DE102011111246B4 - System and method for accelerated feeding of a reactivity influencing medium in a heavy water moderated reactor - Google Patents

Abstract

System for accelerated feeding of a reactivity influencing medium, in particular a neutron absorbing medium, in a heavy water moderated pressurized water reactor (5) with at least one Vorhaltetank (3) for providing the neutron absorbing medium and at least one feed line (7) for medium-conducting and fluidic connection of reactor (5 ) and / or moderator tank and Vorhaltetank (3), wherein between Vorhaltetank (3) and reactor (5) and / or moderator tank an explosion-triggered or explosion-driven valve (6, 10), a so-called. Squib valve, arranged in the feed line (7) is, with which a fast and efficient triggering of the feed of the neutron absorbing medium, in particular the rapid Boreinspeisung, in the reactor (5) and / or moderator tank is effected, wherein the Vorhaltetank (3) in the reactor operation is constantly below the full feed pressure or constantly with the full feed pressure beauf is struck so that this pressure in the case of request and after opening the Squib Valves (6, 10) immediately to feed the respective medium without delay is immediately available and usable, the Squib Valve (6, 10) in less than five milliseconds, preferably within three milliseconds, and releases its passage (18), and due to the immediately available high feed pressure, an optimally fast distribution of the feedstock or the cloud of the reactivity influencing and / or neutron absorbing medium in the moderator tank or reactor (5) and thus a fast and optimal mixing of the feed with the moderator in the reactor vessel effected and made possible and wherein the shear cap (16) of the Squib valve (6, 10) in normal operation of the reactor (5) stuck, in particular not detachable, with the respective pipe or feed line ( 7) is connected or formed integrally with the pipe and / or feed line (7) and / or a leak-tight separation between the neutron-absorbing medium, in particular the borated water, and the reactor (5) and / or moderator tank is effected and ensured and between the squib valve and reactor a rupture disc is provided and the line between the rupture disk and Squib Valve with the respective medium is filled.

Description

The invention relates to a system for accelerated feeding of a reactivity influencing medium, in particular a neutron absorbing medium in a heavy water moderated pressurized water reactor. Furthermore claimed is a corresponding method.

It is well known that in heavy water moderated reactors or also pressurized water reactors, at least in the field of application Germany, the reactivity in the reactor core is controlled by the retraction and extension of control elements or control rods with neutron absorbing materials, in particular graphite rods. For rapid shutdown when requested by the reactor protection system and / or in the event of a malfunction, the control rods or controls will fall into the reactor core due to their mass due to gravitational or gravitational force acting on them, or be let sink into the core by injection of, for example, compressed air.

In addition, or alternatively, in heavily water-moderated reactor types, it is possible to discharge the heavy water acting as moderator suddenly or in a very short time from the moderator tank, causing the chain reaction to be brought to a standstill in the short term due to the lack of moderation of the neutrons. Also heavy water moderated reactors, such as the "Pressurized Heavy Water Moderated Reactor (PHWR)" have become known, which as a diverse device for rapid shutdown a system for fast, preferably delay-free feed of boric acid or other neutron-absorbing media in the moderator tank or in the reactor core. After the respective absorbing medium, in particular boric acid, is introduced, it is distributed in the reactor core or reactor tank and absorbs neutrons due to the high absorption cross section of the boron contained. The absorbed neutrons can no longer contribute to maintaining the chain reaction, which ultimately stops the chain reaction within a very short time.

When feeding in boric acid or other media for rapid deactivation of the chain reaction, it is important that the feed-in takes place as quickly as possible and as quickly as possible upon request. Furthermore, the medium fed in must be distributed as quickly and evenly as possible in the moderator tank in order to effect and ensure rapid interruption of the chain reaction.

One known configuration of a boric acid rapid feed system consists of a multi-redundant array of borated water holding tanks, nitrogen storage tanks, or other high pressure gas, as well as feed lines and rupture disks. Here, the medium to be fed, such as borated water, kept pressureless in normal operation and only put under pressure on a request. This is done by opening a valve between accumulator and Vorhaltetank. The Vorhaltetank is connected by a feed line to the reactor pressure vessel. There is a rupture disk in the feed line. During normal operation, this disc separates the borated water leak-tight from moderator water in heavy water moderated reactor.

If now the pressure in the Vorhaltetank increases, breaks the disc and allows the feed for rapid shutdown.

für x > 0, α > 0 und β > 0 nach Weibull beschreiben. Daraus folgt dass eine zusätzliche Verzögerung bis zum Brechen mit einkalkuliert werden muss. Eine nahezu verzögerungsfreie Auslösung und Freigabe des neutronenabsorbierenden Mediums innerhalb eines Zeitintervalls von weniger als 5 ms ist mit derartigen bekannten Anordnungen bei einem schwerwassermoderierten Reaktor nicht bewirkbar zumindest jedoch nicht gewährleistbar. Dies ist insbesondere auch deshalb von immenser Bedeutung, da ein schwerwassermoderierter Reaktor, im Unterschied zu einem Leichwasserreaktor, im Hinblick auf den Moderator über einen positiven Voidkoeffizienten der Reaktivität verfügt, so dass hier effizientere Sicherheitskonzepte zum Einsatz kommen müssen.A disadvantage of this construction lies in its comparatively slow reaction or its comparatively high reaction time, since bursting of the rupture disks is not desired in normal operation, and these only break at a relatively high differential pressure. However, this pressure must first build up by opening the valves between accumulators and Vorhaltetanks. Overall, this results in a chain of necessary processes and sequences for triggering the "fast" Boreinspeisung. In addition, due to the nature of the fracture mechanics of the specific properties of the rupture disc breaks this not at a defined pressure but with a certain probability in a pressure interval, so that the actual bursting process is fraught with a certain blurring. For a ceramic rupture disk, this bursting probability is generally due to a distribution function

for x> 0, α> 0 and β> 0 according to Weibull. It follows that an additional delay must be taken into account until breakage. An almost instantaneous release and release of the neutron absorbing medium within a time interval of less than 5 ms can not be effected with such known arrangements in a heavy water-moderated reactor, but at least can not be guaranteed. This is especially of immense importance, since a heavy water moderated reactor, unlike a Leichwasserreaktor, with respect to the moderator has a positive void coefficient of reactivity, so here more efficient safety concepts must be used.

From the US5085825 For example, a borated water feed system has become known in a nuclear reactor, which includes a borated water storage tank, an accumulator, and the necessary piping and valves. If necessary, the borated water is pressurized by then a valve between pressure accumulator and the storage tank is opened. Subsequently, a valve in a feed line between the storage tank and a reactor pressure vessel is opened, so that the borated water flows in the direction of the reactor pressure vessel. A disadvantage of this feed system is the comparatively sluggish reaction or large reaction time between initiation of the need and inflow of the borated water into the reactor.

From the US3141470 is known a valve which is driven by an exploding propellant instead of an electric or hydraulic drive. This type of drive increases the opening speed of the valve.

The invention is based on the object of providing a possibility for an improved and more efficient rapid introduction of a neutron-absorbing medium into a heavy-water-moderated reactor, in particular a pressurized-water reactor, which can be implemented with the least possible outlay.

This object is achieved by a system having the features of claim 1. Advantageous embodiments and further developments of the system are specified in further claims and the following description.

Accordingly, the invention relates to a system for accelerated feeding of a reactivity influencing medium, in particular a neutron absorbing medium, in a heavy water moderated pressurized water reactor with at least one Vorhaltetank for maintaining the neutron absorbing medium and at least one feed line for medium-conducting and fluidic connection of the reactor and / or moderator tank and Vorhaltetank , wherein between Vorhaltetank and reactor and / or moderator tank an explosion-triggered or explosion-driven valve, a so-called. Squib valve, is arranged in the feed line, with which a fast and efficient triggering of the feed of the neutron absorbing medium, in particular the rapid Boreinspeisung, in the reactor and / or moderator tank is effected, wherein the Vorhaltetank in reactor operation is constantly below the full feed pressure or constantly charged with the full feed pressure, s o that this pressure immediately in the case of request and after opening the Squib Valve for feeding the medium without delay is immediately available and usable, the Squib Valve in less than five milliseconds, preferably within three milliseconds, triggers and releases its passage, and due the immediately available high feed pressure an optimally fast distribution of the feed cloud or the cloud of the reactivity influencing and / or neutron absorbing medium in Moderatortank or reactor and thus a fast and optimal mixing of the feed with the moderator in the reactor vessel effected and made possible and wherein the shear cap of the Squib valve stuck in normal operation of the reactor, in particular not detachable, connected to the respective pipe or feed line or formed integrally with the pipe and / or feed line and / or a leak-tight separation between the neutronenabsorbi causing medium and in particular the borated water, and the reactor and / or moderator tank is effected and guaranteed and between the Squib valve and reactor rupture disc is provided and the line between the rupture disk and Squib Valve is filled with the respective medium.

In this case, the system according to the invention is based on the use or the use of explosion-triggered and / or explosion-driven valves, the so-called "Squib Valves", for triggering the rapid feed of the respective neutron-absorbing medium, in particular the feed of boron or borated water or boric acid. By using such a Squib Valves, the circuit technology required in a heavily water-moderated reactor can be substantially improved compared to known arrangements and effect and achieve rapid feed-in of the reactivity-influencing medium in the millisecond range with a defined switching time. In addition, a leak-tight separation between the neutron-absorbing medium, in particular the borated water, and the reactor pressure vessel is effected and ensured. To set the desired feed pressure between pressure accumulator and Vorhaltetank at least one pressure control valve is providable. Advantageously, the use of the Squib Valves to keep the Vorhaltetank constantly under full feed pressure or to pressurize him with the appropriate feed pressure, so that this pressure in the case of request and after opening the Squib Valves immediately to feed the respective medium without delay is immediately available and available stands. Thus, the system allows and effects a rapid injection of a neutron absorbing medium in a heavy water reactor with the at least one provided Squib Valve at a permanent pressure of the feed medium in Vorhaltetank tank side and the Squib Valve a leak-tight separation between moderator in Reactor tank and feed medium in the holding tank. Due to the at least one system provided and deployed explosion-triggered or explosion-driven valve (Squib Valve) is a fast immediate, especially within a few, preferably within 3 milliseconds, and immediate triggering of the feed of each neutron absorbing medium on request and a rapid feed of the feed after Triggered by the present at the valve and in the Vorhaltetank directly available high feed pressure effected. In addition, due to the immediately available high feed pressure, an optimally fast distribution of the feed cloud or the cloud of neutron absorbing medium in the moderator tank or reactor and thus a fast and optimal mixing of the feed with the moderator in the reactor vessel can be effected and made possible.

In an advantageous embodiment, an explosive charge is triggered or ignited within the respective Squib Valves when needed and / or request a rapid feed of the neutron absorbing medium, for example a Boreinspeisung, in reactor operation or while the reactor, the targeted a projectile body, in particular a bolt directed against a so-called shear cap shoots and / or accelerates, which shear cap is then sheared off by the projectile body, in particular the bolt and the actual valve of the Squib Valve or its passage ultimately opens and releases the neutron-absorbing medium to the inlet into the reactor or releases.

Furthermore, a corresponding method is claimed for the accelerated feeding of a medium influencing the reactivity, in particular a neutron-absorbing medium, into a heavy water-moderated pressurized water reactor, wherein a reactivity-influencing and / or neutron-absorbing medium is held in at least one holding tank, which by means of a in the respective feed line to medium-conducting connection of the reactor, in particular the reactor pressure vessel, and Vorhaltetank, wherein between Vorhaltetank and reactor, arranged explosion-triggered or explosion-driven valve, a so-called. Squib valve, leak-tight from the moderator in the moderator tank or reactor separated and vorhaltetankseitig charged with a feed pressure, wherein on request opened by triggering the explosion charge the explosion-driven and / or tripped valve and by the applied feed pressure a sch nelle and efficient triggering of the feed of the reactivity influencing and / or neutron absorbing medium, in particular the fast Boreinspeisung, is effected in the reactor, wherein the Vorhaltetank kept constantly under full feed pressure and / or charged with the appropriate feed pressure, so that this pressure Vorhaltetankseitig is applied to the Squib Valve and rests against this and immediately retrieved in the case of request and after opening the Squib Valves for feeding the respective medium without delay and / or provided for feeding the medium in the moderator tank and used in which the squib valve is opened in less than five milliseconds, preferably within three milliseconds, and its passage is released, and by means of the immediately available high feed pressure, the respective feed cloud is optimally rapidly distributed and / or the cloud of the reactivity affecting medium and / or the neutron absorbing medium in the moderator tank or reactor is optimally distributed quickly and thus the feed medium with the moderator in the reactor vessel efficiently and homogeneously, that is mixed evenly in a very short time with relatively little effort, the shear cap d It Squib valve in the normal operation of the reactor fixed, in particular not detachable, connected to the respective pipe or feed line or integrally with the pipe or is arranged at this, whereby a leak-tight separation between the reactivity influencing medium and / or neutron-absorbing medium, in particular the borated water, and the reactor pressure vessel and / or the moderator therein is made or effected and guaranteed and between the Squib valve and reactor rupture disc is arranged and the line between rupture disk and Squib Valve is filled with the respective medium.

In this case, the inventive method on the use or the use of explosion-triggered and / or explosion-driven valves, the so-called Squib Valves, for triggering the rapid feed of the respective neutron-absorbing medium, in particular the feed of boron or borated water or boric acid, from. In this case, the shearing cap of the Squib valve in the normal operation of the reactor is fixed, in particular not detachable, connected to the respective pipe or feed line or integrally with the pipe or arranged at this. As a result, a leak-tight separation between the neutron-absorbing medium, in particular the borated water, and the reactor pressure vessel and / or the moderator therein is produced or effected and ensured. In addition, the Vorhaltetank is constantly kept under full feed pressure or acted upon by the corresponding feed pressure, so that this pressure Vorhaltetankseitig is also applied to the Squib Valve and rests on this and in case of need and after opening the Squib Valves immediately to feed the respective medium without delay immediately available and / or is available for feeding the medium in the moderator tank and is usable. Furthermore, by means of the immediately available high feed pressure, the feed cloud optimally distributed quickly or optimally distributed the cloud of neutron absorbing medium in moderator tank or reactor and thus the feed medium with the moderator in the reactor vessel efficiently and homogeneously, ie in a very short time with relatively little effort evenly , mixed.

Advantageously, the method can be used for execution and use on the system described above.

In an advantageous embodiment, an explosive charge is triggered or ignited when needed and / or request a rapid feed of the reactivity influencing, in particular neutron absorbing medium, for example, a Boreinspeisung, in reactor operation or while the reactor is operating within the respective Squib Valves, the projectile body, in particular a bolt targeted and directed shoots against a so-called shear cap and / or accelerated, which shear cap is then sheared off by the projectile body, in particular the bolt and the Squib valve or its passage ultimately opens and the reactivity influencing, in particular neutron absorbing medium to the inlet releases into the reactor or releases.

In addition, the invention also encompasses and claims the use of a previously described system and / or a squib valve within the boriding system of a heavy water moderated reactor, in particular a pressurized water reactor, for the accelerated feeding or rapid feeding of boron, borated water or boric acid.

The further explanation of the invention as well as advantageous embodiments and developments is based on some figures and embodiments.

In 1 A known configuration of a rupture disc boring system for a heavy water moderated reactor is shown.

In the 2 there is shown an exemplarily formed system for rapid introduction of borated water into a heavy water moderated reactor with an explosion triggered valve.

In the 3 an exemplary trained system according to the invention for the rapid feeding of borated water into a heavy water moderated reactor with an explosion-triggered valve and an additional bursting disc shown.

In 4 an exemplary designed explosion-triggered valve is shown.

In 1 is a schematic representation of a previous, known configuration shown. This configuration or arrangement includes a reactor 5 , a holding tank 3 , an accumulator 1 and at least one valve 2 and a rupture disk 4 and at least one feed line 7 which all components 1 . 2 . 3 . 4 . 5 Fluidic and medium-conducting interconnects. The accumulator 1 is through one or more valves 2 from the reserve tank 3 separated. When opening the valve or valves 2 A high pressure builds up in front of the rupture disk 4 which eventually causes them to burst, leaving the respective medium in the reactor 5 is fed.

In 2 an embodiment of a system for rapid feed is shown. The end 1 known valve 2 omitted here, leaving the reserve tank 3 constantly under the same pressure as the accumulator 1 , In the feed-in line 7 to the reactor 5 is now in place of the rupture disk 4 a squib valve 6 , Similar to the rupture disk 4 in the previous example the 1 now separates the Squib Valve 6 the reactor medium and the feed medium in normal operation leak-tight from each other. The Squib Valve 6 however, withstands the full feed differential pressure. Upon request, the explosion charge is ignited and the squib valve 6 opens its passage and the feed medium is fed almost instantaneously.

3 shows a further embodiment variant in which in addition to the previous execution of 2 between Squib Valve 6 and reactor 5 again a rupture disk 4a located. The line between Squib Valve 6 and rupture disc 4a is exemplarily filled with borated water (feed medium). Due to the incompressibility of the water is available after opening the Squib Valves 6 almost instantaneous the full differential pressure at the rupture disk 4a so that it breaks immediately and the feed takes place. An advantage of this design is that the Squib Valve 6 also relatively far from the reactor 5 can be installed remotely. This may make maintenance easier.

In 4 is an example performed between Vorhaltetank 3 and heavy water moderated reactor 5 in the feed-in line 7 Can be arranged explosion-triggered or explosion-driven valve 10 , a so-called squib valve, with which a fast and efficient triggering of the feed of the neutron-absorbing medium, in particular the rapid Boreinspeisung, in the respective reactor 5 is feasible. In the Squib Valve 10 is an explosion charge 12 provided, which, when triggered or ignited, a projectile body 14 , in particular a bolt, targeted or directed against a so-called shear cap 16 shoots and / or accelerates, which shear cap 16 then through the projectile body 14 , in particular the bolt, is sheared off and the actual valve of the Squib valve or its passage 18 ultimately opens and the neutron absorbing medium to the inlet to the reactor 5 releases or releases. The opening of the Squib Valve 10 takes place within a few milliseconds, preferably within 3 milliseconds. The shear cap 16 the Squib Valve 10 in normal operation of the reactor 5 fixed, in particular not detachable, with the respective pipe or feed line 7 connected or integrally formed with the pipe and / or feed line. As a result, a leak-tight separation between the neutron-absorbing medium, in particular the borated water, and the reactor pressure vessel is effected and ensured.

The present invention also encompasses any combinations of preferred embodiments as well as individual design features or developments, provided that they are not mutually exclusive.

Claims (5)

System for accelerated feeding of a reactivity influencing medium, in particular a neutron absorbing medium, in a heavy water moderated pressurized water reactor ( 5 ) with at least one holding tank ( 3 ) for the provision of the neutron-absorbing medium and at least one feed line ( 7 ) for the medium-conducting and fluidic connection of reactor ( 5 ) and / or moderator tank and holding tank ( 3 ), whereby between Vorhaltetank ( 3 ) and reactor ( 5 ) and / or moderator tank an explosion-triggered or explosion-driven valve ( 6 . 10 ), a so-called squib valve, in the feed line ( 7 ), with which a rapid and efficient triggering of the feed of the neutron-absorbing medium, in particular the rapid boron feed, into the reactor ( 5 ) and / or moderator tank, whereby the holding tank ( 3 ) is constantly under the full feed pressure in reactor operation or is constantly supplied with the full feed pressure, so that this pressure in the case of request and after opening the Squib Valves ( 6 . 10 ) can be immediately accessed and used immediately for feeding the respective medium without delay, whereby the Squib Valve ( 6 . 10 ) in less than five milliseconds, preferably within three milliseconds, and its passage ( 18 ) and, due to the immediately available high feed pressure, an optimally fast distribution of the feed cloud or of the cloud of the reactivity-influencing and / or neutron-absorbing medium in the moderator tank or reactor ( 5 ) and thus a fast and optimal mixing of the feed with the moderator in the reactor vessel is effected and made possible and wherein the shear cap ( 16 ) of Squib Valve ( 6 . 10 ) in normal operation of the reactor ( 5 ), in particular not detachable, with the respective pipe or feed line ( 7 ) or in one piece with the pipe and / or feed line ( 7 ) and / or a leak-tight separation between the neutron-absorbing medium, in particular the borated water, and the reactor ( 5 ) and / or moderator tank is effected and ensured and between the Squib valve and reactor a rupture disc is provided and the line between the rupture disk and Squib Valve is filled with the respective medium. System according to claim 1, characterized in that at least one explosion-triggered and / or explosion-driven valve ( 6 . 10 ) is provided and used to initiate the rapid feed of the respective neutron absorbing medium, in particular the feed of boron or borated water or boric acid, in which when needed and / or request a rapid feed of the neutron absorbing medium in the reactor operation within the respective Squib Valves ( 6 . 10 ) provided explosive charge ( 12 ) is triggered and / or ignited, the one projectile body ( 14 ), directed against a so-called shear cap ( 16 ) shoots and / or accelerates which shear cap ( 16 ) then through the projectile body ( 14 ) and the passage ( 18 ) and the neutron absorbing medium to the inlet into the reactor ( 5 ) and / or the moderator tank is released or released. Process for accelerated feeding of a reactivity influencing medium, in particular a neutron absorbing medium, into a heavy water moderated pressurized water reactor ( 5 ), wherein in at least one holding tank ( 3 ) a reactivity influencing and / or neutron absorbing medium is maintained, which by a in the respective feed line to the medium-conducting compound ( 7 ) of reactor ( 5 ), in particular the reactor pressure vessel, and Vorhaltetank ( 3 ), whereby between Vorhaltetank ( 3 ) and Reactor ( 5 ), arranged explosion-triggered or explosion-driven valve ( 6 . 10 ), a so-called squib valve, by the moderator in the moderator tank or reactor ( 5 ) is separated leak-tight and vorhaltetankseitig is acted upon by a feed pressure, wherein upon request by triggering the explosion charge ( 12 ) the explosion-driven and / or tripped valve ( 6 . 10 ) and by the applied feed pressure a rapid and efficient triggering of the feed of the reactivity influencing and / or neutron absorbing medium, in particular the fast Boreinspeisung, in the reactor ( 5 ), the holding tank ( 3 ) is kept constantly under full feed pressure and / or charged with the appropriate feed pressure, so that this pressure tank on the front side also on the Squib Valve ( 6 . 10 ) is applied and is applied to this and in case of request and after opening the Squib Valves immediately for feeding the respective medium without delay and immediately retrieved and / or provided for feeding the medium in the moderator tank and is used, the Squib Valve ( 6 . 10 ) in less than five milliseconds, preferably within three milliseconds, and its passage ( 18 ) is released, and by means of the immediately available high feed pressure, the respective feed cloud is optimally quickly distributed and / or the cloud of the reactivity influencing medium and / or the neutron-absorbing medium in the moderator tank or reactor ( 5 ) is distributed optimally quickly and thus the feed medium with the moderator in the reactor vessel efficiently and homogeneously, that is mixed evenly in a very short time with relatively little effort, the shear cap ( 16 ) of Squib Valve ( 6 . 10 ) in normal operation of the reactor ( 5 ), in particular not detachable, with the respective pipe or feed line ( 7 ) or integrally with the tube or is arranged thereon, whereby a leak-tight separation between the reactivity influencing medium and / or neutron absorbing medium, in particular the borated water, and the reactor pressure vessel and / or the moderator therein is produced or effected and ensured and a rupture disc is placed between Squib Valve and reactor and the line between the rupture disk and Squib Valve is filled with the respective medium. A method according to claim 3, characterized in that when needed and / or on request of a rapid feed of the neutron absorbing medium, for example a Boreinspeisung, in reactor operation or while the reactor is running ( 5 ), within the respective Squib Valve ( 6 . 10 ) an explosion charge ( 12 ) is triggered or ignited, whereby a projectile body ( 14 ), in particular a bolt, targeted or directed against a so-called shear cap ( 16 ) is shot and / or accelerated, which shear cap then through the projectile body ( 14 ), especially the bolt, and the Squib Valve ( 6 . 10 ) or its passage finally opened and the neutron-absorbing medium to the inlet into the reactor ( 5 ) is released or released. Use of at least one explosion-triggered and / or explosion-triggered and / or explosion-driven valve ( 6 . 10 ), a so-called squib valve, together with a rupture disc for triggering the rapid feed of the respective neutron-absorbing medium, in particular the feed of boron or borated water or boric acid, into a heavy water-moderated pressurized water reactor ( 5 ) in less than 5 ms, with the rupture disc between the squib valve and the reactor is arranged and the line between the rupture disk and Squib Valve is filled with the respective medium.

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