KR102716583B1 - System and method for removing a target of investigation from a nuclear reactor, and a radioactive nuclide generation system - Google Patents

Abstract

The investigation target removal system comprises at least one storage vessel (34) for receiving an activated investigation target (16) from an instrumentation system (12) of a reactor; a discharge pipe (30) comprising a first discharge pipe section (38), a second discharge pipe section (40), and a connection between the first and second discharge pipe sections (38, 40); and a supply of pressurized gas (52) connected to the first discharge pipe section (38) for pressurizing the discharge pipe (30). The second discharge pipe section (40) is coupled to the instrumentation system (12), and the first discharge pipe section (38) has an outlet port (32) assigned to the storage vessel (34); a first locking element (36) for blocking movement of the activated investigation target (16) into the storage vessel (34), the first locking element (36) being positioned between the outlet port (32) and the connection; and at least one opening (46) positioned between the first locking element (36) and the connection, wherein the at least one opening (46) is connected to a supply of pressurized gas (52). Also shown is a method for removing an activated investigation target from a radioisotope generation system, a discharge pipe, and an instrumentation system of a reactor.

Description

System and method for removing a target of investigation from a nuclear reactor, and a radioactive nuclide generation system

The present invention relates to a system and method for removing an irradiation target from a commercial nuclear reactor and to a radionuclide generation system.

Radionuclides are used for medical purposes as well as for various technical and scientific purposes. Usually, radionuclides are produced in research reactors or cyclotrons. However, since the number of facilities for commercial production of radionuclides is already limited and is expected to decrease, it is desirable to provide alternative production areas.

The neutron flux density of the core of a commercial reactor is measured by introducing a solid spherical probe into an instrumentation tube passing through the reactor core. Therefore, it has been proposed that the instrumentation tube of a commercial reactor should be used for the production of radionuclides.

EP 2 093 773 A2 proposes that an existing instrumentation tube system, traditionally used to house a neutron detector, can be used to generate radionuclides during normal operation of a commercial nuclear reactor. In particular, a spherical irradiation target is linearly pushed into and removed from an instrumentation finger extending into the reactor core. Based on the axial neutron flux profile of the reactor core, the optimum position and exposure time of the target within the reactor core are determined. A driving gear system is used to move and maintain the irradiation target in the instrumentation tube system.

Due to the high activity of the activated irradiation target recovered from the instrumentation system and the limited space within the reactor containment, the activated target is difficult to handle. In particular, the activated target containing the radionuclide must be filled and stored in a container providing heavy radiation shielding. The chamber for the Traversing Incore Probe (TIP) system and/or the Aero-ball Measuring System (AMS) does not have any structure for packaging and transporting such a heavy container. It is also too costly to provide additional water locks in the reactor containment to handle the activated target and shielded container.

WO 2016/173664 A1 describes a radiation treatment system for inserting and retrieving an irradiation target into and from an instrumentation tube of a reactor core. The target treatment system comprises a target retrieval system, a target insertion system, and a delivery gas supply, which are mounted on a movable support. The target retrieval system comprises an exit port having a locking element for blocking movement of the irradiation target into an exit port. The exit port is formed as an inverted U and defines an apex and a first section and a second section of the exit tube. The locking element blocks movement of an activated irradiation target in the first exit tube section. The exit port comprises a gas inlet port coupled to a first gas supply tube, and a ball valve connecting the exit port to a storage vessel and an external exhaust system. The target treatment system comprises at least one movable magnet, which is capable of distinguishing between an irradiation target and a positioning target if the two types of targets differ in their magnetic properties.

WO 2017/012655 A1 describes a method for producing a radionuclide from an irradiation target of a commercial nuclear reactor using at least one instrumentation tube system of the reactor. An irradiation target and a dummy target are inserted into the instrumentation fingers and the irradiation target is activated by exposing them to a neutron flux within the reactor to form a desired radionuclide. The dummy target is used to maintain the irradiation target at a predetermined axial position in the reactor core corresponding to a pre-calculated neutron flux density sufficient to convert the irradiation target into a radionuclide. By exposing the dummy target and/or the activated irradiation target to a magnetic field, the dummy target is separated from the activated irradiation target such that one of the dummy target or the activated irradiation target is retained in the instrumentation tube system and the other of the activated irradiation target or the dummy target is released from the instrumentation tube system. To this end, the dummy target and the activated irradiation target have different magnetic properties.

WO 2017/012655 A1 describes a method for harvesting activated irradiation targets from an instrumentation system of a nuclear reactor. For this purpose, the instrumentation system is coupled to an outlet pipe having a apex, an outlet port, and a locking element between the apex and the outlet port. The activated irradiation targets are passed from the instrumentation system into the outlet pipe and their movement is blocked by the locking element. Due to the apex, the activated irradiation targets can be separated into two positive targets. By releasing the locking element, the irradiation targets between the locking element and the apex can be passed under the action of gravity into a storage vessel coupled to the outlet port, wherein another positive target is held in the outlet pipe by the apex.

However, the amount of active survey targets in the discharge pipe between the locking element and the apex is fixed due to the given geometry of the harvesting system including the discharge pipe and the apex. However, the size of the available and required storage vessel often turns out to be not large enough to integrate the given amount of active survey targets.

At the same time, the use of dummy targets that can be magnetically separated from the irradiated target is not desirable, since the number of targets in the reactor is limited and the irradiation time can be very long, in some cases up to two weeks. Therefore, it is desirable to use the necessary positions for the dummy targets relative to the irradiated target.

It is therefore an object of the present invention to provide a target removal system for radionuclide production in commercial reactors, which enables the use of a larger quantity of irradiated targets and provides improved possibilities for splitting the activated irradiated targets. It is also an object of the present invention to provide a radionuclide production system comprising such a target removal system. Furthermore, it is an object of the present invention to provide a method for removing the activated irradiated targets of such a system.

The above object is solved by a system for removing an investigation target according to claim 1, a system for generating radioactive nuclides according to claim 11, a discharge pipe according to claim 12, and a method for removing an activated investigation target according to claim 14.

According to a first aspect, the present invention provides a target removal system, comprising: at least one storage vessel for receiving an activated target from an instrumentation system of a nuclear reactor;

A discharge pipe comprising a first discharge pipe section, a second discharge pipe section, and a connection between the first and second discharge pipe sections, and

A supply of pressurized gas connected to the first discharge pipe section for pressurizing the discharge pipe,

The second discharge pipe section is coupled to the instrumentation system, the first discharge pipe section comprises an outlet port assigned to the storage vessel, a first locking element for blocking movement of an activated investigation target into the storage vessel, the first locking element being positioned between the outlet port and the connection, and at least one opening positioned between the first locking element and the connection, the supply of pressurized gas being connected to the at least one opening.

The investigation target removal system comprises several possibilities for separating the activated investigation target into smaller quantities. The first separation can be accomplished by the shape of the discharge tube. Due to the first locking element, a predefined quantity of the investigation target can be maintained between the first locking element and the connection of the first discharge tube section (herein referred to as "full quantity").

When the first locking element is released, all the investigation targets in the first discharge pipe section are removed from the discharge pipe and can be collected by the storage vessel, for example, due to gravity. This corresponds to methods known in the art for harvesting activated investigation targets from the instrumentation system of a reactor. However, in this case, a storage vessel sufficiently large to accommodate a "full amount" of activated investigation targets is required.

In contrast, by providing at least one opening positioned between the first locking element and the connection, it is possible to further divide the "full amount" of the investigation target into smaller predefined amounts. The size of this predefined amount is determined by the position of the at least one opening within the first discharge pipe section. In practice, the at least one opening is positioned in a lateral region of the first discharge pipe section, i.e. on the transverse side.

Providing an opening is an easy way to realize the supply of pressurized gas into the exhaust pipe. It is also an easy solution for integrating the investigation target removal system of the present invention into an existing system.

For example, at least one opening relates to a borehole drilled into the first discharge pipe section, so that an already existing discharge pipe can be used.

By applying a stream of pressurized gas through at least one opening, all the investigation targets above the height of the at least one borehole can be transferred back to the second discharge pipe section and even back to the measuring finger of the reactor. Alternatively or additionally, an additional holding position, precisely a stop position, can be defined for the at least one opening, which is located closer to the reactor. For example, this holding position, precisely a stop position, is defined by another opening of the discharge pipe, which can interact with another locking element.

In any case, only a predefined amount of the activated investigation target is retained in the first discharge pipe section by the pressurized gas, this amount corresponding to the distance between the first locking element and the position of the at least one opening.

The predefined amount of activated investigation targets can be adjusted depending on the size of the available storage container in which the activated investigation targets are typically stored.

The separation of the different amounts of objects in the first exhaust section is based solely on the position at which the gas is fed into the exhaust pipe. Therefore, there is no need to implement means for distinguishing between different types of objects, for example by magnetic properties. In this way, there is no need to use dummy targets in the irradiation target removal system of the invention in order to realize a smaller predefined amount of activated irradiation targets compared to the "full amount" defined by the geometry of the exhaust pipe. Thus, all possible positions within the measuring fingers of the atomic core of the reactor can be used for the production of irradiation targets. This increases the production efficiency of radionuclides compared to previous radionuclide production systems. At the same time, the division is simplified, since no magnetic system is required to select the activated irradiation targets.

However, it is still possible to use dummy targets if desired. This may be necessary if it is known that there are positions of the instrumentation fingers in the reactor that do not exhibit sufficiently high neutron flux densities to obtain sufficient quantities of the desired radionuclide for the intended application.

Preferably, the dummy target is magnetic, which allows the use of a selector mechanism to easily distinguish and separate the dummy target from the activated investigation target.

Furthermore, the investigation target removal system of the present invention can be easily applied to existing installations by providing at least one opening in the first discharge pipe, in particular by drilling at least one bore hole, and connecting this at least one opening, in particular the bore hole, to a supply of pressurized gas.

The apex can be formed at the connection of the first and second discharge tube sections, the first and second discharge tube sections being directed downwardly from the apex. The first locking element is positioned between the outlet port and the apex. At least one opening is positioned between the first locking element and the apex. As mentioned above, the investigation target removal system includes a first separation completed by the shape of the discharge tube, i.e. the apex. Due to the first locking element, a predefined amount of the investigation target can be maintained between the first locking element and the connection of the first discharge tube sections (herein defined as a "full amount"). The apex and both tube sections directed downwardly from the apex ensure that gravity can be used for the first separation.

In one embodiment, at least one of the openings may comprise a set of openings provided circumferentially in the first exhaust pipe section at the same height. In this way, pressurized gas can be supplied evenly into the first exhaust pipe, especially when the individual openings are provided symmetrically around the circumference of the first exhaust pipe section. This leads to better control of the system when separating the investigation target. In particular, a set of bore holes is drilled circumferentially in the first exhaust pipe section at the same height.

In a preferred embodiment, the pressurized gas supply comprises a control valve, preferably a 2/2 control valve. This provides an easy and safe way to control the flow of gas from the gas supply.

To avoid gas from the gas supply leaking around the exhaust pipe, at least one opening may be housed in a pressure-tight encapsulation. This also increases the stability and control of the pressurized gas applied. In addition, the pressure-tight encapsulation may have radiation shielding properties.

In another embodiment, the second locking element may be positioned in a path leading from the instrumentation system. For example, the second locking element is positioned in a path connecting the second discharge pipe section and the instrumentation system.

In this way, already activated irradiation targets, which have been removed from the first exhaust pipe section, in particular from the entire exhaust pipe, by the pressurized gas, can be blocked in their path before they are re-filled into the instrumentation system. Thus, it is possible to prevent the irradiation targets from re-entering the reactor and being exposed to additional radiation exposure, without the need for precise adjustment and control of the gas flow into the first exhaust pipe section.

The system can be used to move the investigation target several times between the path and the first exhaust pipe section, in particular between the exhaust pipe sections, so that, for example, several times a predefined amount of activated investigation target can be collected from the total amount present in the radionuclide generation system and filled into individual storage containers.

The possibility for the operator to collect a specific amount of the activated survey target can be additionally increased by providing, in particular by drilling, at different heights in the first discharge pipe section, two or more sets of openings, for example bore holes, each set of openings, in particular bore holes, being connected to a pressurized gas supply.

Another set of openings may be connected to the same or different pressurized gas supplies, which may have coupled or decoupled valves to control the gas flow.

The distance between the first locking element and the first set of apertures can be different from the distance between the first set of apertures and the second set of apertures.

By selecting different height differences between the first locking element and the different sets of openings, it becomes possible to select between several different predefined quantities of the investigation target held in the first discharge pipe section, for example depending on the set of openings through which the pressurized gas is supplied.

The outlet port can be positioned above the assigned storage vessel so that a predefined amount of the activated investigation target can be transferred to fill the storage vessel, for example by the action of gravity. The distance between the outlet port and the corresponding opening in the storage vessel is adapted so that the investigation target does not miss the opening.

Preferably, the outlet port is configured to couple to an assigned storage container. Providing a removable connection between the outlet port and the storage container allows working in a closed system and minimizing the risk of operator exposure to radiation.

In a preferred embodiment, the outlet port comprises a stop valve for pressure-tight sealing of the outlet port. This outlet port prevents pressurized gas supplied through the at least one opening from leaking out of the outlet port, thereby increasing the pressure in the first discharge pipe section and thereby lifting the investigation target above the at least one opening past the connection of the discharge pipe, in particular past the apex.

In a further preferred embodiment, at least one cartridge is provided, which is assigned to an investigation target and contains a radionuclide precursor material. Preferably, the cartridge comprises a housing containing one or more investigation targets. In this way, the radionuclide precursor material may not need to form a spherical investigation target that is sufficiently stable to withstand the conditions of the radionuclide generation system. In particular, in pneumatically driven systems, the forces acting on the target can be large and not all preferred precursor materials are capable of forming a sufficiently stable spheroid that does not break or shatter when exposed to such forces. By using at least one cartridge, only the cartridge must withstand the mechanical forces encountered. Thus, radionuclides can be generated that would otherwise not be obtained.

In another aspect, the present invention provides a radionuclide generation system comprising a target removal system as described above.

According to a further aspect, the present invention provides an exhaust pipe for an investigation target removal system, in particular for an investigation target removal system as described above, the exhaust pipe comprising at least a first exhaust pipe section, the first exhaust pipe section comprising:

― Exit port assigned to the storage container of the investigation target removal system;

― A first locking element for blocking movement of an activated investigation target into a storage container, said first locking element being located between a connection port to the instrumentation system of the investigation target removal system and an outlet port; and

― at least one opening positioned between the first locking element and the connection port, said at least one opening being configured to provide an interface to a supply of pressurized gas.

In fact, the discharge pipe according to the present invention relates to the lower part of the investigation target removal system described above.

In another aspect, the present invention provides a method for removing an activated investigation target from an instrumentation system of a nuclear reactor, the method comprising:

a) coupling at least one measuring finger of the measuring tube system to a target removal system as described above;

b) a step of sending an activated investigation target from the measuring finger into the discharge tube and blocking movement of the activated investigation target out of the discharge tube by the first locking element;

c) separating a predefined amount of the activated investigation target from another amount of the activated investigation target within the discharge tube; and

d) a step of assigning an outlet port to a storage container and releasing the first locking element, thereby allowing a predetermined amount of the activated investigation target within the discharge pipe to pass into the storage container;

The separating step comprises supplying pressurized gas into the first exhaust section through at least one opening, thereby driving a different amount of the activated investigation target from the first exhaust section through the connection and into the second exhaust section, thereby maintaining a predetermined amount of the activated investigation target in the first exhaust section.

In addition to the pressurized gas used to divide or, more precisely, separate the activated investigation targets, a pneumatically actuated drive system may be provided, configured to insert the investigation targets, for example so-called air balls, into the measuring fingers and to remove the investigation targets, for example air balls, from the respective measuring fingers after their activation.

Additional aspects and advantages of the present invention will become more apparent from the following description of preferred embodiments and the accompanying drawings in which like elements are designated by like reference numerals. The preferred embodiments are given by way of example only and are not intended to limit the scope of the invention, which is evident from the appended claims.

In the drawing;
FIG. 1 is a schematic diagram illustrating a setup of a radioactive nuclide generation system according to the present invention;
FIG. 2 illustrates a schematic outline of the investigation target removal system of the present invention;
Figure 3 illustrates an enlarged view of a first discharge pipe section of the investigation target removal system;
Figure 4 illustrates the first discharge pipe section of Figure 3 during separation of the investigation target;
FIG. 5 illustrates the first exhaust pipe section of FIG. 3 after separation of the investigation target while releasing a predefined amount of activated investigation target;
Figure 6 is a schematic sequence of a method according to the present invention;
Figure 7 illustrates another schematic outline of a radionuclide generation system setup according to the present invention; and
Figure 8 illustrates an enlarged view of the first discharge pipe section of the investigation target removal system.

The present invention contemplates that a commercial reactor may be used to produce radionuclides. In particular, conventional air ball measurement systems or other instrumentation systems of a commercial reactor may be modified and/or supplemented to enable effective and efficient production of radionuclides.

Part of an exemplary instrumentation configuration of a commercial Aero-ball Measuring System (AMS) or Traversing Incore Probe (TIP) system is used to guide an irradiation target into the reactor core and to guide an activated irradiation target out of the reactor core. Activation of the target is optimized by positioning the irradiation target in a predetermined region of the reactor core that has sufficient neutron flux to completely convert the parent material of the irradiation target into the desired radionuclide(s).

Suitable positioning of the investigation targets can be achieved by dummy targets made of an inert material, preferably a magnetic material, and the dummy targets and the investigation targets are arranged sequentially in the instrumentation system so as to form a column of targets within the instrumentation finger. In practice, the investigation targets are located at pre-calculated optimal axial positions within the reactor core, and the other positions are occupied by inert dummy targets or are empty. However, it is desirable to use as many positions within the instrumentation finger for the investigation targets as possible instead of the dummy targets, in order to produce as many radionuclides as possible.

Figure 1 illustrates the basic setup of a radionuclide production system (6) within a commercial nuclear power plant (8). In contrast to research reactors, the purpose of a commercial reactor is to produce electrical power. Commercial reactors are typically rated for 100+ megawatts of electrical power.

The basis of the radionuclide generation system (6) described in the exemplary embodiment is derived from a conventional Aero-ball Measuring System (AMS) used to measure the neutron density of the core of a nuclear reactor, i.e., the reactor core (10).

A plurality of aero balls are arranged in a linear sequence, thereby forming an aero ball row. The aero balls are substantially spherical or round probes, but may have other shapes, such as oval or cylindrical, as long as they can be moved through the conduit of the instrumentation system.

The aero ball measuring system includes a pneumatically actuated drive system configured to insert an aero ball into a measuring finger and remove an aero ball from each measuring finger after activation.

Typically, the measuring finger extends into and passes through the core (10) over its entire axial length.

Referring to FIG. 1, a commercial reactor includes an instrumentation system (12) including at least one instrumentation finger (14) passing through a reactor core (10) of the reactor. The instrumentation system (12) is configured to allow insertion and removal of an investigation target (16), and optionally a magnetic or non-magnetic dummy target (18) (see FIG. 2), into the instrumentation finger (14).

The aero ball measurement system for a commercial reactor is adapted to process a target (16) having a round, cylindrical, oval, or spherical shape and a diameter corresponding to the gap of the measurement fingers (14) of the aero ball measurement system. Preferably, the diameter of the target (16, 18) is in the range of 1 mm to 3 mm, preferably about 1.7 mm.

The instrumentation system (12) has a conduit that passes through an access barrier (11) of the reactor and is coupled to one or more instrumentation fingers (14). Preferably, the instrumentation fingers (14) pass through the pressure vessel cover of the reactor, and the instrumentation fingers (14) extend substantially the entire axial length of the reactor core (10) from top to bottom. The ends of each of the instrumentation fingers (14) at the bottom of the reactor core (10) are closed and/or provided with stops, so that the probe targets (16) inserted into the instrumentation fingers (14) form a column, each target (16) being at a predetermined axial position.

In a preferred embodiment, the commercial reactor is a pressurized water reactor. More preferably, the instrumentation system (12) is derived from a conventional air ball measurement system of a pressurized water reactor (PWR), such as an EPR ^TM or Siemens ^TM PWR reactor.

However, those skilled in the art will recognize that the present invention is not limited to use in the aero ball measurement system of a PWR reactor. Rather, it is also possible to use the instrumentation tube of a transverse in-core probe (TIP) of a Boiling Water Reactor (BWR), the view port of a CANDU reactor, and the temperature measurement and/or neutron flux channels of a heavy water reactor.

As illustrated in FIG. 1, the instrumentation system (12) is connected to a target drive system (20) configured to insert the investigation targets (15) and optionally the dummy targets (18) into the instrumentation fingers (14) in a predetermined linear order and to press the investigation targets (16) and the dummy targets (18) outward from the instrumentation fingers (14), thereby maintaining the linear order of the targets (16, 18). Preferably, the dummy targets are magnetic.

Preferably, the target drive system (20) is pneumatically operated to allow rapid processing of the investigation target (16) and optionally the dummy target (18) using a pressurized gas such as nitrogen or air.

The target drive system (20) receives an activated investigation target (16) and optionally a dummy target (18) from the instrumentation system (12) and cooperates with an investigation target removal system (22) configured to deliver a predetermined amount (16') of the activated investigation target (16) into a shielded storage vessel (34) (see FIG. 2). The investigation target removal system (22) will be described in more detail below with reference to FIG. 2.

Referring further to FIG. 1, an Instrumentation and Control Unit (ICU) (24) is connected to the target drive system (20) and the target removal system (22) as well as the online core monitoring system (26) to control activation of the target (16). Preferably, the ICU (24) is also connected to a fault monitoring system (28) of the aero ball measurement system to report any errors. The fault monitoring system (28) may also be designed not to be connected to the existing aero ball measurement system, but may be connected directly to the main control room.

According to an embodiment, the core monitoring system (26) and the measurement and control unit (24) are configured such that the activation process for converting the irradiation target (16) into the desired radionuclide is optimized by taking into account the actual state of the reactor, in particular the current neutron flux, fuel burn-up, reactor power and/or loading. Thus, the optimal axial irradiation position and irradiation time can be calculated for optimal results. However, it does not matter whether the actual calculation is performed in the ICU (24) or by the core monitoring system (26) of the aeroball measurement system.

The irradiation target (16) is made of non-fissile material and comprises a suitable precursor material for the generation of a radionuclide used for medical and/or other purposes. More preferably, the irradiation target (16) is comprised of a precursor material which, when activated by exposure to a neutron flux present in a reactor core (10) of an operating commercial nuclear reactor, is transformed into the desired radionuclide. Useful precursor materials include Mo-98, Yb-176, and Lu-176, which are transformed into Mo-99 and Lu-177, respectively. However, it is to be understood that the present invention is not limited to the use of any particular precursor material.

The optional dummy target (18) is made of an inert material, which is substantially inactive under the conditions of the reactor core (10) of the operating reactor. Preferably, the dummy target (18) can be made of an inexpensive inert material and can be reused after a short decay time, thereby further reducing the amount of radioactive waste. More preferably, the dummy target is magnetic.

For use in a conventional aeroball measuring system, the probe target (16) and the dummy target (18) are formed in a round shape, preferably a spherical or cylindrical shape, so that the targets (16, 18) can slide smoothly and be easily guided into the measuring tube system (12) of the aeroball measuring system by a pressurized gas such as air or nitrogen and/or under the action of gravity.

The investigation target removal system (22) of the present invention is schematically illustrated in more detail in FIG. 2.

An exhaust pipe (30) is connected to the metering finger (14) via an air ball conduit of the metering pipe system (12). The exhaust pipe (30) is configured to receive an investigation target (16) driven outwardly of the metering finger (14) after activation is complete. A linear sequence of the investigation targets (16) and/or dummy targets (18) is maintained in the exhaust pipe (30). Preferably, the exhaust pipe (30) is located outside of the reactor core (10), but within an accessible area inside the reactor containment vessel.

The discharge tube (30) has an outlet port (32) assigned to at least one storage container (34, 34') for receiving an activated investigation target (16) from a measuring finger (14). The outlet port (32) may be positioned above the assigned storage container (34) to be filled, or may be coupled to and/or removably connected to the assigned storage container (34). At least one of the storage containers (34, 34') preferably has a shield to minimize operator exposure to radiation from the activated investigation target (16).

A first locking element (36) is provided in the discharge pipe (30) to block movement of the activated investigation target (16) into the storage container (34, 34'). The first locking element (36) may be a magnetically or mechanically actuated limiting element, preferably a pin spanning the discharge pipe (30).

Referring to FIG. 2, the exhaust pipe (30) includes a first exhaust pipe section (38), a second exhaust pipe section (40), and a peak (42) formed at a connection between the first and second exhaust pipe sections (38, 40). The peak (42) is the highest point of the exhaust pipe (30). The first and second exhaust pipe sections (38, 40) are directed downward from the peak (42).

An outlet port (32) is positioned at the free end of the first discharge pipe section (38) opposite the apex (42), and a second discharge pipe section (40) is coupled to the instrumentation system (12). The outlet port (32) includes a stop valve (44) for pressure-tight sealing of the discharge pipe (30).

In the illustrated embodiment, a set of openings (46) are provided circumferentially in the first discharge pipe section (38) between the first locking element (36) and the apex (42), i.e. the connection. In particular, the openings (46) are realized by bore holes drilled into the first discharge pipe section (38). The set of openings (46) is surrounded by a pressure-tight capsule (48) which is connected to a supply of pressurized gas (52) by a 2/2 control valve (50).

Preferably, air or nitrogen is used as the pressurized gas. The pressurized gas can be supplied from the target drive system (20).

Although a set of openings (46) is provided in the illustrated embodiment, as will become apparent below, a single opening (46) is also sufficient to connect to the supply (52).

In the embodiment illustrated in FIG. 2, the apex (42) at the connection between the first discharge pipe section (38), the second discharge pipe section (40), and the tube sections (38, 40) on both sides is formed in the shape of an inverted U.

Other profiles of the discharge pipe (30) are also possible.

Preferably, the apex (42) is formed between the first and second discharge tube sections (38, 40) and is configured with a radius sufficiently small to effectively separate the target rows of the first and second tube sections (38, 40) from each other in the first separation.

The operation of the investigation target removal system (22) of the present invention will now be described in more detail.

For a period of time sufficient to convert the investigation target (16) into the desired radionuclide(s), the investigation target (16) is activated in the measurement finger(s) (14) and driven into the measurement tube system (12) from the measurement finger(s) (14) using a pressurized gas, such as air or nitrogen, supplied from the target drive system (20).

The discharge pipe (30) is connected to the conduit of the instrumentation system (12) for receiving the investigation target (16) (step (S1) of FIG. 6). A gate system (not shown), such as a three-way valve, may be used to guide the investigation target (16) into the discharge pipe (30) of the investigation target removal system (22). The investigation target (16) of the instrumentation finger(s) (14) is retained in the discharge pipe (30).

At this time, as shown in FIG. 3, access to the outlet port (32) of the discharge pipe (30) is blocked by the first locking element (36), providing a stop to the activated investigation target (16) and preventing the target (16) from leaving the discharge pipe (30) (step (S2) of FIG. 6).

Typically, there are so many investigation targets (16) in the discharge pipe (30) that they accumulate to a level above the set of openings (46). In such a case, a predefined amount (16') of activated investigation targets (16) can be separated from another amount (16") of activated investigation targets (16) in the discharge pipe (30) (step (S3) of FIG. 6).

For this purpose, pressurized gas is fed into the first exhaust pipe section (38) via at least one opening (46), in particular a set of openings (46). This drives another amount (16") of activated investigation target (16) above the at least one opening (46) from the first exhaust pipe section (38) through the junction of the first and second exhaust pipe sections (38, 40), i.e. the apex (42) in the illustrated embodiment, into the second exhaust pipe section (40) (as indicated by the arrows in FIG. 4 ).

Another amount (16") of the activated investigation target (16) is driven into the second exhaust pipe section (40) which can be filled by the third amount (16''') of the activated investigation target (16). Thereafter, the third amount (16''') of the activated investigation target (16) is driven out of the second exhaust pipe section (40) by the pressurized gas. Alternatively or additionally, the other amount (16") of the activated investigation target (16) is also driven out of the second exhaust pipe section (40).

For example, an intermediate storage is provided to ensure that another quantity (16") of activated investigation targets (16) and/or a third quantity (16''') of activated investigation targets (16) are not driven back into the reactor core (10).

Finally, the first locking element (36) and the stop valve (44) are released, and the predefined amount (16') of the activated investigation target (16) still located within the first discharge pipe section (38) can be sent under the action of gravity into the storage vessel (34) assigned to the outlet port (32) (as illustrated in step (S4) of FIGS. 5 and 6).

After collecting a predetermined amount (16') of activated investigation target (16), the stop valve (44) in the outlet port (32) is closed to provide a pressure-tight seal of the outlet port (32) and the discharge pipe (30), and the sealed storage vessel (34) is then removed manually or by an automated handling device.

The above process steps can then be repeated to segment and harvest additional quantities of activated investigation targets (16) until all activated investigation targets (16) have been removed from the instrumentation system (12). The system is then ready to start a new radionuclide production system.

An additional embodiment of a radioactive nuclide generation system is shown in FIG. 7.

For identical parts, the same symbols are used as in the embodiments shown above. The same features and advantages of the equivalent parts apply here as well.

In this embodiment, the first discharge pipe section (38) presents a first set of openings (46) surrounded by a first pressure-tight capsule (48) and a second set of openings (46') surrounded by a first pressure-tight capsule (48'). Each capsule (48, 48') is connected to a supply of pressurized gas (52, 52') by a 2/2 control valve (50, 50').

In the illustrated embodiment, the control valves (50, 50') and the supply of pressurized gas (52, 52') are independent of each other. However, they may also be a single control valve (50) connected to a single supply (52).

The first and second sets of openings (46, 46') are positioned at different heights in the first discharge pipe section (38). Additionally, the height difference between the first and second sets of openings (46, 46') is different from the height difference between the first set of openings (46) and the first locking element (36). In this way, depending on the height at which the pressurized gas is applied in step (S3) (see FIG. 6), different amounts of activated investigation targets (16) can be maintained in the first discharge pipe section (38) and then delivered to the storage vessel (34).

Therefore, when a predetermined amount of the activated investigation target (16) is collected several times, it is possible to first collect an amount corresponding to the height difference between the first locking element (36) and the first set of openings (46), and then collect a second amount corresponding to the height difference between the first locking element (36) and the second set of openings (46').

Additionally, in this embodiment, a second locking element (54) is positioned in a path (56) leading from the metering pipe system (12). In practice, the path (56) connects the second discharge pipe section (40) and the metering pipe system (12).

The second locking element (54) prevents the investigation target (16) that is pushed out of the discharge pipe (30) from flowing back into the measuring finger (14) of the reactor, particularly into the reactor core (10).

It is also possible that the path (56) represents an additional connection to an additional tube through which the investigation target (16) can be delivered during the separating step (S3) of FIG. 6.

In another embodiment, as shown in FIG. 8, a cartridge (58) assigned to the investigation target (16) is used. Otherwise, the radionuclide generation system (6) represents other components as described for the other embodiments and similar reference numerals are used to refer to similar parts.

By using a cartridge (58), the precursor material and the produced radionuclide need not form a stable spheroid capable of withstanding the forces generated by the radionuclide generation system (6). Only the cartridge (58) containing one or more investigation targets (16) need be sufficiently stable to be transmitted from the metering finger (14) into the discharge tube (30).

Claims (14)

As an irradiation target removal system,
At least one storage vessel (34) for receiving an activated investigation target (16) from the instrumentation system (12) of the reactor;
A discharge pipe (30) including a first discharge pipe section (38), a second discharge pipe section (40), and a connection portion of the first and second discharge pipe sections (38, 40); and
A supply section (52) of pressurized gas connected to the first discharge pipe section (38) to pressurize the discharge pipe (30).
Including,
The above second discharge pipe section (40) is coupled to the above metering pipe system (12),
The above first discharge pipe section (38):
― An outlet port (32) assigned to the above storage container (34);
― A first locking element (36) for blocking movement of the activated investigation target (16) into the storage container (34) - The first locking element (36) is positioned between the outlet port (32) and the connection portion -; and
― At least one opening (46) positioned between the first locking element (36) and the connecting portion, to which a supply portion (52) of the pressurized gas is connected,
The above outlet port (32) includes a stop valve (44) for sealing the above outlet port (32) in a pressure-tight manner,
The at least one opening (46) comprises a set of openings (46) provided in the first discharge pipe section (38) in a circumferential direction at the same height.
Investigation target removal system. In the first paragraph,
An apex (42) is formed at the connection between the first and second discharge pipe sections (38, 40),
The first and second discharge pipe sections (38, 40) are directed downward from the top (42),
The above first locking element (36) is located between the outlet port (32) and the apex (42),
At least one of the above openings (46) is located between the first locking element (36) and the apex (42).
Investigation target removal system. In the first paragraph,
The above pressurized gas supply unit (52) includes a control valve (50).
Investigation target removal system. In the third paragraph,
The above control valve (50) is a 2/2 control valve.
Investigation target removal system. In the first paragraph,
At least one of the above openings (46) is contained in a pressure-tight encapsulation (48).
Investigation target removal system. In the first paragraph,
The second locking element (54) is located in the path (56) originating from the instrumentation system (12).
Investigation target removal system. In the first paragraph,
Two or more sets of openings (46, 46') are provided at different heights of the first discharge pipe section (38), each set of openings (46, 46') being connected to the pressurized gas supply (60).
Investigation target removal system. In Article 7,
The distance between the first locking element (36) and the first set of openings (46) is different from the distance between the first set and the second set of openings (46, 46').
Investigation target removal system. In the first paragraph,
At least one cartridge (58) is provided, which is assigned to the above investigation target (16), and the cartridge (58) contains a radioactive nuclide precursor material.
Investigation target removal system. A radioactive nuclide generation system comprising a target removal system (22) according to any one of claims 1 to 9. As a discharge pipe for the investigation target removal system (22),
The above discharge pipe (30) includes at least a first discharge pipe section (38),
The above first discharge pipe section (38):
― An outlet port (32) assigned to a storage container (34) of the above-mentioned investigation target removal system (22);
― A first locking element (36) for blocking movement of an activated investigation target (16) to the storage container (34) - the first locking element (36) is positioned between the connection port to the instrumentation system (12) of the investigation target removal system (22) and the outlet port (32); and
― at least one opening (46) positioned between the first locking element (36) and the connection port, wherein the at least one opening (46) is configured to provide an interface to a supply of pressurized gas (52),
The above outlet port (32) includes a stop valve (44) for sealing the outlet port (32) in a pressure-tight manner,
The at least one opening (46) comprises a set of openings (46) provided in the first discharge pipe section (38) in a circumferential direction at the same height.
discharge pipe. In the 11th paragraph, the discharge pipe is for a target removal system (22) according to any one of the 1st to 9th paragraphs.
discharge pipe. As a method for removing an activated investigation target (16) from a reactor instrumentation system (12),
a) a step of coupling at least one measuring finger (14) of the measuring tube system (12) to a target removal system (22) according to any one of claims 1 to 9;
b) a step of sending the activated investigation target (16) from the measuring finger (14) into the discharge pipe (30) and blocking movement of the activated investigation target (16) out of the discharge pipe (30) by the first locking element (36);
c) a step of separating a predefined amount (16') of the activated investigation target (16) from another amount (16") of the activated investigation target (16) within the discharge pipe (30); and
d) a step of assigning the outlet port (32) to a storage container (34) and releasing the first locking element (36) to send the predetermined amount (16') of the activated investigation target (16) of the discharge pipe (30) into the storage container (34).
Including,
The above separation step is,
A step of supplying pressurized gas into said first discharge pipe section (38) through said at least one opening (46), thereby driving another amount (16") of activated investigation target (16) above said at least one opening (46) from said first discharge pipe section (38) through said connection and into a second discharge pipe section (40), thereby maintaining a predetermined amount (16') of activated investigation target (16) in said first discharge pipe section (38).
method. delete