Method for identifying spent fuel assembly

FIELD: identifying o spent fuel assemblies with no or lost identifying characteristics for their next storage and recovery.

SUBSTANCE: identifying element is made in the form of circular clip made of metal snap ring or of two metal semi-rings of which one bears identification code in the form of intervals between longitudinal through slits. Clip is put on fuel assembly directly under bracing bushing and clip-constituting semi-rings are locked in position relative to the latter without protruding beyond its outline. For the purpose use is made of mechanical device of robot-manipulator type. Identification code is read out by means of mechanical feeler gage and sensor that responds to feeler gage displacement as it engages slits. Identifying elements are installed under each bracing bushing.

EFFECT: ability of identifying fragments of spent fuel assembly broken into separate parts before recovery.

10 cl, 4 dwg

 

Prerequisites

The invention relates to the identification of fuel assemblies (FA), preferably waste (SFA), extracted from a nuclear reactor or basin storage and intended for subsequent storage and processing.

Prior art

Identification of fuel rods, from which we collect the fuel Assembly or the fuel Assembly is carried out in different ways and at different stages.

In particular, there is a method of identifying nuclear fuel rod by fastening to the shell of the core of the label or label with an individual identification number in the form of optically scanned bar-code attached at the beginning of the production process and removed at the end of this process (U.S. patent No. 4587407, IPC G 06 K 07/10, 1986). Doffing and donning label - the procedure is not cheap and do not involve the identification of the fuel rod at the stage of its use.

Another approach is the identification not only at the production stage, but also at the stage of use of the fuel rods, the application is not withdrawn and is not destroyed in service identifier.

In particular, there is a method for identification of fuel rods using sufficiently explosive to blow the solid particles such as beads on the surface of the protective casing of the fuel element, thanks is formed, the mark in the form of four-digit numbers (Japan patent No. 63278765, the IPC 24 1/04, G 21 C 3/02, 1988). Such identification is carried out at the production stage, but the identification mark is stored in the operation.

Another way of identifying the fuel rods involves the application of a bar code on the surface of the protective casing or on the ends of the fuel rod electrolytic polishing with subsequent optical reading (Japan patent No. 3237389, IPC G 21 C 3/02, 1991). The main condition - providing a sharp contrast marking strips relative to the metal to which they are applied.

However, this method is not applicable in the case of operation of the fuel assemblies in the Russian reactors, where the surface FA polluted different kinds of deposits.

There is a method of engraving an identification code with a laser beam on the sheath of the fuel element or end plates in a gas atmosphere consisting of a mixture gas of argon and oxygen (U.S. patent No. 4822987, IPC G 06 K 01/12, 19/06). The problem here is that the laser engraving may lead to violation of the metallurgical structure of the protective shell (shell) of the fuel cladding, which may in operation be violating its integrity. So for shells, marked the thus, the required strict control of risk zones formed this label.

Any such identification features enables remote reading or using a special optical reader installed along the route of the pipeline in the production process of the fuel rods or assemblies, or using video cameras designed to work under water, if control is performed during the storage.

A known method for the identification of nuclear fuel elements, which consists in applying through the perforation on the flat surface of one of the components, bonded to an identifiable object, identification of several characters, each of which has its own depth. The set of such characters is the identification code of the object (European patent 1067475, IPC G 06 K 19/06, G 06 K 7/10, publ. 10.01.2001). The reading is carried out using the scanning head containing a device for measuring the depth of these characters.

It is obvious that such marks should not be applied directly to the surface of the protective casing of the fuel rod, as it leads to an even greater extent than laser engraving, to the disturbance of the structure of the material of the protective cover.

A known method for the identification of the spent fuel Assembly, sanlucas is the action scene in the preliminary formation of parts, mechanically fixed on this build, own identification code in the form of a mechanical cut, the distance between which is an identification sign to be read in the control process. This item is a pen-holder, mechanically bonded to the top plate, tightening fuel rods together (U.S. patent No. 5167910, IPC G 21 C 03/32, publ. 01.12.92). This method and the selected prototype of the proposed method.

Despite this diversity of methods of identification, there is a real situation, when the fuel assemblies after their operation in the nuclear reactor, have so damaged or contaminated identification marks or not have them at all, and that the implementation of a reliable unambiguous identification of these objects is problematic. There was a problem additional identification SFA after removing them from the reactor or from the pool store, through which you could trace the trajectory of further movement of the Assembly or its parts. When this identification label on the SFA should be not so much on the details, remote from the fuel cells, but also directly in contact with them. This is because it is necessary to exercise control over the entire operational process performed by the SFA, including its cutting. The application and entification signs known methods for irradiated fuel, as a rule, ethnologica, unsafe, uneconomic and inefficient.

The essence of the invention.

The task of the present invention is to create such a method of identification, which would cause identification code on spent fuel assemblies in the extraction process of the Assembly of the reactor or of the cooling pool. Application code should be providing the necessary nuclear safety, with minimal cost, without damage to the fuel elements without compromising the integrity of the parts forming the Assembly. Place one or at least two) of application code should be such that code (or codes on different fragments) continued (continued) portions of the Assembly when it is cutting. If this identification code must retain its readability when the manipulation Assembly, to be resistant to various kinds of contamination and not to increase the dimensions of the fuel Assembly.

This task is solved in that in the method for the identification of the spent fuel Assembly, consisting in a preliminary run on the details, mechanically fixed to the Assembly, mechanical cut, geometric parameters which are used for forming the identification code read in the control process, with the help of AB is somatizirovanne, for example, the optical devices according to the invention the specified item is performed in the form of a clamp, which cover the Assembly of fuel elements with the formation of the annular identification item code cut which is made in the form of through slots along its side surface, with the installation of the items is carried out using an automated device in the extraction process of Assembly of a nuclear reactor or from the pool store.

Technical result of this authentication method is that the identification codes can be assigned to each fragment Assembly, cut for disposal, which is very important when subsequent separate storage until processing. The identification element of the proposed type can be installed in the extraction process of the Assembly after operation of the reactor or from the pool store. This is especially true in cases when, for some reason, identification signs come in complete disrepair or simply absent, and the control further passage of Assembly is required. The installation of such an identification element is an automatic device that represents the robot arm.

Such identification elements - clamps assumes ustanavli the diamonds in the zones between the tightening sleeve, employees for combining the individual fuel elements in the Assembly, so that when cutting SFAS each fragment has retained its identity element. The preferred area is located in the immediate vicinity of the tightening sleeve (below it or above it), in which the clamp set flush relative to the tightening sleeve, so as not to increase the transverse size of the Assembly and reduce the mechanical loading of the clip when possible transverse deformation of the SFAS in the long-term storage.

As the clamp can be used a split metal ring.

In another embodiment, the clamp may be formed of two metal half-rings that secure the cover Assembly of fuel elements and fix them relative to each other, while at least one of the half-rings perform with spring area. The presence of a springy section allows you to “walk” diameter clamp depending on variations of the lateral dimension of the SFA. In the clip, made in the form of a split ring, this effect is due to changes in the natural gap when additional mechanical loading.

The clamps when installing them in areas that are directly under compression sleeves, can be fixed relative to the specified tightening the collet. While the security is guaranteed by maintaining the original position of the identification elements when cutting SFA.

Code cutouts can be made inclined relative to the generatrix of the cylindrical surface of the clamp. Due to the tilt is more reliable detection of cut in optical registration code, because when performing a cut without tilt, there can be overlap one or more through-cut lateral surface of any of the fuel elements, with the result that he will be treated as missing.

Code cutouts can be made the same width, but at different distances relative to each other. In this case, the identification feature will serve transformed into a code distance between the cutouts.

In another embodiment, the code cutouts may have a different width, then identification feature addition will serve transformed into a code width of cut.

In addition, the appropriate one of the notches to perform longer than the rest and use it as a reference point, i.e. mark the original position in the process of optical registration identifier.

The reading of the identification sign may be produced by moving the probe type mechanical ball relative to the side surface of the identification element and the sensor fixing transverse displacement of the ball due to the interaction of eg the side surface and the slits. However, it is preferable to use automatic optical reader, registering the image code on the perimeter of the clip.

List of drawings

Figure 1 presents a fragment of SFAS identification element is a clamp in the form of a split metal ring. Figure 2 shows the details of the identification element - clip representing two metal half rings in the initial state. Figure 3 shows a fragment of SFAS installed metal semicircles forming the identification element is a belt directly under the tightening sleeve. Figure 4 (a, b) gives options code cut on scans of identification elements.

Figure 1 shows a fragment of an Assembly consisting of individual fuel elements 1, which are combined with the tightening sleeve 2 relative to the Central rod 3, which is intended to capture the Assembly when it is moved. The identification element is a clamp made in the form of a split metal ring 5 through the code cutouts 6, covers the fuel elements 1 in the area, providing its locked position and the reading of the identification sign. Figure 2 shows the details in the form of half-rings 7 and 8, on opposite sites are toothed latches 9 and 10, 11 and 12. meyda l-shaped hooks 13 for fixing the half-rings relative to the tightening sleeve. On one of the metal half-rings perform force stretchable section 14 formed, for example, cutouts 15, shifted relative to each other.

A specific example scenarios

Previously on the surface of the part from which is formed a clip of one form or another, perform end-to-end cut-outs 6, the distances between which are non-repeating ID code of this fragment of the SFA. One of the cuts, which will serve as the initial point of registration (rapper), perform longer in comparison with others. Next, form a clamp, consisting of one or two parts whose shape provides a snug, but not deforming the coverage of an Assembly of fuel elements 1. Using the robotic arm in a particular phase extraction Assembly of fuel elements from the pool store or from the reactor put the clamp on Assembly. Putting a clamp in the form of a metal split ring is top-down vertical position of the Assembly due to the small force of deformation in the form stretch ring 5 in the process of moving it to the installation location in its proper place. Fixing clamp at the expense of the forces of elasticity, reducing the gap to the initial value. The size of the initial gap and coeff is they of elasticity of the ring is chosen such that in order to take into account fluctuations of the transverse size of the Assembly. The installation of the clip of the two half-rings 7 and 8 is also performed using the robotic arm, which sums up these details from opposite sides to the area immediately under the tightening sleeve 3. Geometrical dimensions of semirings selected such as to avoid damage of fuel elements. Angular and longitudinal movement of the half-rings in the area of installation ensure the fixing of l-shaped hooks 12 between the projections on the sleeve 2 and the actuation timing latches. In the same way establish the second identification element is a clamp next to the other tightening sleeve. Multiple ID elements on one spent fuel Assembly allows you to identify the accessory parts to a specific Assembly after it is split.

After installation of the identification element using one or another method of identification reads code defined by the distance between the slits 6. The most preferable optical method of reading, registering the image code on the perimeter of the clip (see figa, b) with subsequent conversion of certain parameters in a digital binary code. The memorized signal is further used for control purposes.

Prom the industrial applicability

The creation of this technical solution is one of the urgent tasks in the nuclear industry as it provides control over hazardous materials to be stored for a long time. Analysis of the technical means used at the enterprises of the nuclear energy complex, showed that the technical implementation of the method is quite feasible. Complication of automated means for performing the manipulation of the fuel assemblies is not required. Installation of robot manipulators in the necessary areas of the moving assemblies for installation of identification elements and devices for reading the identification codes is quite a task.

1. The method of identifying the spent fuel Assembly, consisting in a preliminary run on the details, mechanically fixed to the Assembly, mechanical cut, geometric parameters which are used for forming the identification code is read into the control process using automated, for example by optical means, characterized in that the specified item is performed in the form of a clamp, which cover the Assembly of fuel elements with the formation of the annular identification item code cut which is made in the form of narrow through slots of the IDC is ü its lateral surface, the installation details are carried out using an automated device in the extraction process of Assembly of a nuclear reactor or from the pool store.

2. The method of identifying the spent fuel Assembly according to claim 1, wherein the set of at least two annular identification element on different parts of the spent fuel Assembly in the zones between the tightening sleeve serving to combine the individual fuel elements in the Assembly.

3. The method of identifying the spent fuel Assembly according to claim 1 or 2, characterized in that the annular element is installed in close proximity relative to one of the tightening sleeve and flush with it.

4. The method of identifying the spent fuel Assembly according to any one of claims 1 to 3, characterized in that the annular identification element using a split metal ring.

5. The method of identifying the spent fuel Assembly according to any one of claims 1 to 3, characterized in that the annular identification element using two metal half-ring, which covers the Assembly of fuel elements, and fix them relative to each other, while at least one of the half-rings perform with springy plot.

6. the manual identification of the spent fuel Assembly according to claim 4 or 5, characterized in that the annular identification element is fixed relative to nearby tightening sleeve.

7. The method of identifying the fuel Assembly according to any one of claims 1 to 6, characterized in that the cross-cutting code cutouts perform inclined relative to the generatrix of the cylindrical surface of the annular identification element.

8. The method of identifying the fuel Assembly according to any one of claims 1 to 7, characterized in that the cross-cutting code cutouts perform the same width, but at different distances relative to each other.

9. The method of identifying the fuel Assembly according to any one of claims 1 to 7, characterized in that the cross-cutting code cutouts perform different width.

10. The method of identifying the fuel Assembly according to any one of claims 1 to 9, characterized in that one of the end-to-end code cutouts perform are longer than others and use it as a reference in the registration process identifier.



 

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FIELD: identifying o spent fuel assemblies with no or lost identifying characteristics for their next storage and recovery.

SUBSTANCE: identifying element is made in the form of circular clip made of metal snap ring or of two metal semi-rings of which one bears identification code in the form of intervals between longitudinal through slits. Clip is put on fuel assembly directly under bracing bushing and clip-constituting semi-rings are locked in position relative to the latter without protruding beyond its outline. For the purpose use is made of mechanical device of robot-manipulator type. Identification code is read out by means of mechanical feeler gage and sensor that responds to feeler gage displacement as it engages slits. Identifying elements are installed under each bracing bushing.

EFFECT: ability of identifying fragments of spent fuel assembly broken into separate parts before recovery.

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