RU2687081C1 - Method for automatic control of recovered alpha-contamination of fuel elements and device for its implementation - Google Patents

Abstract

FIELD: nuclear physics and equipment.

SUBSTANCE: group of inventions relates to nuclear power engineering. Method for automatic control of the removed radioactive contamination of surface of the fuel elements (RRCS) consists in the fact that the fuel element is supplied to the unit for removing the smear into the position of contact with the fabric tape directed to the fuel element across its axis. Dense reduction of surface of fuel element is performed with tape. Fuel element is pulled through the smear removal unit, the tape is moved with the obtained active contact spot on the smear into the detection unit. Performing registration α-activity of the contact spot on the smear. Setting friction force F_c. Smear removal rate K_c is calibrated_. Fuel element is drawn through the reduction zone, controlling the friction force of the fuel rod sliding along the reduced band F, after removal of squeezing, movement of band with smear on spacing l_sp under radiometer and count rate measurement n_cou from α-activity of the contact spot on the smear is calculated flow density α-particles q, averaged over strained surface of fuel element, by formula q=n_cou/(β* K), where K=K_c [1+λ*(F*F¹ _c-1)]. There is also a device for performing a method for automatic control of the radioactive contamination of the surface of a fuel element.

EFFECT: group of inventions enables to achieve required values of RRCS control accuracy and efficiency of fuel elements.

8 cl, 7 dwg

Description

The branch of application of the method is nuclear power. The method is designed to control the removed radioactive contamination of the surface (SRZP) of fuel elements (fuel rods) of the core type when they are released from production at manufacturers of fuel rods and fuel assemblies for the nuclear reactors. The predominant application of the method is the control of fuel rods with a diameter of 9.7 and 10.5 mm with SNUP-fuel for the reactor facility BREST - OD-300 (fuel based on mixed uranium and plutonium nitrides) and fuel rods with a diameter of 6.9 mm plus wire with MOX - fuel for BN-800 RP (fuel based on mixed oxides of uranium and plutonium).

The method is applicable to control rod fuel elements of other types of nuclear facilities both in Russia and abroad.

Contamination of the fuel cladding surface with radioactive dust occurs mainly when the fuel rod is equipped with a fuel column (nuclear material tablets in the open end of the shell). SRHR is a radiation hazard and is the main source of environmental pollution. Therefore, the automatic lines for the manufacture of fuel rods include posts controlling the radioactive contamination of the external surfaces of the fuel rods.

Known line of control and sorting thiel (RF patent №2242297 VS07S 5/04, publ. 20.03.2004), and automated fuel assembly line for nuclear power reactors of the type BN (RF patent №2094866, publ. 10.27997, IPC G21C 21/00). The known technical solutions provide for the use of instrumental means of controlling the total (removable and fixed) radioactive contamination of the surface. Instruments (detectors) are located above the surface of the fuel rods in the output control line of the fuel rods.

The disadvantages of the known technical solutions is that without additional procedures for cleaning the surface and re-checking fuel rods, it is impossible to identify removable (non-fixed) contamination, which significantly complicates the technological process of manufacturing fuel rods. In addition, in the production of fuel rods with high-background fuel there arises the problem of completely eliminating the influence of background radiation on the reliability of SRHR control.

Radiation safety services at nuclear fuel cycle enterprises during dosimetric monitoring of surfaces of any kind are guided by the document “Guidelines on methods for monitoring contamination of surfaces of working premises, equipment, vehicles and other objects with MUK 2.6.1.016-99 by nuclides”. In this case, an indirect measurement procedure is preferably used - the smear method. The smear method is a method of measuring the levels of SRHR by contact activity from a controlled surface to the wiping material. There are methods of dry and wet smears. In this technology, we apply the method of dry smears.

Let us highlight the main indicators of the dry smears method according to the document MUK 2.6.1.016-99, relating to our task:

1) The stroke removal coefficient K is determined by the formula (6.3.10): K = Q _m / Q _nov , where Q _m and Q _noв are the total activities of the smear and the rubbed surface, respectively. In turn, Q _nob = q * S, where q is the flux density of α-particles from the surface S. Wherefrom q = Q _m / (K * S) = n _m / (β * K * S), where n _m is the speed pulse counting of the α-particle detector, and β - detector sensitivity to the α-particle flow.

2) The coefficient of smear removal (Section 6.3.1), equal to K = 0.2 ± 0.02 = 0.2 * (1 ± 0.1), rel. units, obtained with the force of pressing the contact patch of the smear to the test surface (Section 6.3.6), equal to Р = 4 ± 1 kgf = 4 * (1 ± 0.25) kgf, When pulling the fuel rod through its compression zone, the fabric overcomes the friction force fabrics for steel, equal to F = μ _tr * P = μ _tr * 4 * (1 ± 0.25), kgf. Based on this result, the dependence of the removal coefficient of a dry smear on the measured friction force can be represented in a linear approximation by an equation that takes into account the differences in the measurement conditions of the current fuel element from the calibration conditions of the monitoring post K = K _to [1 + 0.4 * (F * F ^-1 _to -1)], where K and K _c are the coefficients of smear removal, determined on the current fuel element and on the caliber (test sample), respectively, rel. unit; F is the frictional force of pulling the fuel through compressed fabric, measured while monitoring the current fuel, kgf; F _к is the friction force of the broach through the crimped fabric, given by the adjustment of the crimping device during the calibration of the stroke removal coefficient, kgf.

3) The magnitude of the smear removal coefficient is proportional to the ratio of the contact area of the smear to the area of the wiped surface, therefore using the data in Table 2 of p. 6.3.1 of the MUK in the method of automatic control of SRHR without taking this factor into account may lead to incorrect results. Note that according to clause 6.3.6 for handicrafts, the ratio of the contact area of a smear to the area of the wiped surface is 0.1.

The dry-smear method described in MUK 2.6.1.016-99 is not aimed at the tasks of technological control of SRZP of long-dimensional cylindrical products, such as fuel elements.

In JSC "Machine-Building Plant", Electrostal, in 1983. for the line for manufacturing fuel rods of VVER-440, a device for cleaning the surface of the casing from fuel dust in the end zone at the orifice through which fuel pellets are loaded into the fuel cladding was developed and put into operation. The device contains a cassette, in the case of which two coils with a wiping tape are mounted (one of them with a rotation drive - for winding a tape with strokes, the other without a drive - for winding a clean tape), guide rollers for the tape, a roller crimping mechanism for the fuel cladding stepwise transversely directed to the fuel element, and the node of rotation of the fuel element. The device works as follows: fuel-filled fuel elements are fed by an open hole into the area of the crimp mechanism, where a tight ribbon coverage of the face dusty zone of the shell with a length of about 50 mm is performed. Next, the fuel rod scrolls to a predetermined number of full revolutions, then the compression mechanism opens, the fuel element is removed, and the tape with a stroke shifts by a fixed pitch, winding onto the receiving coil. The method of cleaning the end zone of the fuel cladding from fuel dust, implemented in this device, solves only the technological problem, but, as will be seen from the following, it can be modified to be used as a means of controlling SRHR.

The closest to the technical nature of the claimed method is a method of automatic control of the removed α-contamination of fuel rods and device for its implementation (RF patent No. 2615036, CL G01T1 / 16, publ. 03.04.2017). Known technical solution adopted as a prototype.

According to the formula, the method is characterized in that the fuel element is fed step by step to the position of contacting its surface with a material made in the form of a wiping tape, which is transversely guided to the fuel rod, while the fuel element surface is mechanically compressed with a tape with a normalized force not exceeding the tensile strength of the wiping tape and a fuel rod, but sufficient for sorption of α-particles on it, then the fuel rod is pulled through the tape until a dry smear is obtained (spots), the crimping mechanical force is removed and the tape is moved with the obtained th spot on the step at the detector which detects the presence of contamination, and the possibility of review of the detector should exceed the size of the contact patch on the smear, and then determine the level of contamination of the fuel element in the prescribed manner with a known measurement equipment. The size of the obtained spot with α-radiation is 40 × 30 mm. The step length for moving the ribbon with a stroke from the position of contacting the fuel element with the ribbon to the center of the sensitive area of the detector is 90-100 mm.

A device that implements the method is characterized by the fact that it contains a cassette in which the feeding and receiving coils of the wiping tape are mounted, each with a tape count sensor and a rotation motor with a stepper motor, guide rollers, a tape tension sensor, and a crimping mechanism with two tapes moving segments with an internal diameter of a fuel rod connected by a rod to a spring unit mechanically connected through an effort sensor to an electric cylinder having a stepping motor, a detector displaced one step from the position crimping mechanism of a fuel rod and electrically connected with radiometric equipment, a logic controller electrically connected to a force sensor, measuring equipment and an industrial computer.

The disadvantages of the prototype are:

For the operation “step-by-step supply of a fuel element to the position of contacting its surface with a material”: the definition of a “step-by-step supply” of a fuel element to the position of its crimping with a tape, data on the step size, an explanation of the reason for using the step-by-step mode is missing, as well as instructions on how to feed the fuel element to the position his girth tape. Specifying the feeding method is very important, since if you feed the fuel element with the top plug forward, when it is pulled through the SRZP girth position, it will be removed in the direction from the polluted portion of the fuel rod to the clean side. In this case, according to the desorption mechanism, the sorbent will be transferred (contaminated) from the zone of the upper plug to the entire surface of the fuel cladding. For this reason, the measurement result will be distorted in a smaller direction, and the contaminated fuel will be recognized as clean and will fall into suitable products, which is unacceptable.

For the operation "compression of the fuel element cloth tape":

- for the circumference of a fuel element with a ribbon, a device containing a plurality of assemblies is proposed, is relatively complex both in manufacturing and in controlling its operation during operation. But the main thing is that without reconstructing the grip device, it is impossible to use the proposed control method as a universal measure for fuel rods of all sizes, for example, fuel rods for BN-800 RP (∅ 6.9 plus wire) and fuel rods for BREST RU (∅ 9.7 and 10 ,five);

- The normalized compression force of a fuel element with a tape is set from the condition that the tensile strength of the ribbon and fuel rod is not exceeded, but sufficient for sorption of particles with a cloth, and the quantitative determination is not known in the sources. Therefore, this statement in the formula is not binding.

»:According to the operation "moving the tape with a stroke to the step

":

- The length of the tape movement is given in the form of specific figures “from 90 to 100 mm”, and thus the tolerance field for the step length is set to 10 mm. With this tolerance, the positioning error of the active smear spot relative to the center of the detector window will be ± 5 mm. It will lead to a decrease in the accuracy of control due to the non-uniformity of sensitivity over the detector surface relative to the center, which according to the manufacturers of the detector is ± 35%.

- With the specified tolerance, a simple accounting of tape consumption by the number of strokes taken (by the number of tape pulling steps taken) will be inaccurate due to the accumulated error. For example, with the length of the original fresh ribbon in a roll of 50 m, the error in determining the residue by the number of steps may be ± 2.5 m, which is undesirable. Therefore, in the prototype proposed a complicated scheme for taking into account the number of the tape on the coils of the winding and winding of the tape.

- the binding of the step size taken to be equal to (95 ± 5) mm to the overall dimensions of the equipment used and to the diameter of the fuel rod is unknown, which raises questions when assembling components into a single device design, especially when it is necessary to apply the gamma-neutron barrier protection of the scintillator radiation coming from a fuel element.

On the operation “determination of the level of contamination of a fuel element in the prescribed manner using known measuring equipment”: there are no sources where you can find a description of the operations “in the prescribed manner” and apply them in the method of monitoring the SRZP of a fuel element. If this record refers to the MUK 2.6.1.016-99, then in it the “established procedure” refers only to the manual work carried out by the personnel of the radiation safety service and is not related to process control. The method of automatic control of SRZP fuel rods should have an order determined primarily by metrology. A device that implements the method must undergo a calibration operation of the smear rate K and the sensitivity of the detector to the alpha particle flux β. Factors determining the duration of the count rate measurement should be identified. The conditions for accepting fuel rods according to an alternative feature, the main control objective, should be defined.

In terms of the size of the contact patch with alpha radiation: the size of the contact patch, equal to 40 * 30 mm, is a special case of many. These dimensions are determined by the specified angle of coverage of the fuel element, the diameter of the controlled fuel element and the width of the ribbon. For example, for BN fuel rods, the perimeter of coverage at best will be 20 mm, rather than 30 mm. The width of the tape is selected in the prototype, based on the conditions of a typical supply of keeper tapes for the electrical industry. However, if the tape width is chosen according to the condition of equality of the stripping coefficient with the value given in clause 6.3.1.3 of the MUK 2.6.1.016-99, then its width will be about 200 mm.

On the structural design of the device that implements the method of control:

The main unit of the device that implements the control method is a removable cassette - a multifunctional unit that performs operations with the tape: movement, tension, measurement of the movement step and the number of steps. However, the long-term practice of the atomic industry enterprises has shown that in the conditions of remote work with radioactive substances, the aggregation of equipment reduces its reliability, therefore the rule “for each function has its own workplace”. The use of a cassette complicates the design of the requirements for automating the calibration of the sensitivity of the detector according to a reference measure. However, the main disadvantage of using a cassette is that a cassette that has been in the first zone (in a radiation protection shelter) cannot be transferred without prior decontamination to cleaner rooms for reloading rolls, this is additional human labor in unhealthy conditions.

Thus, the lack of mechanization of the detector’s auto-calibration and the need to create a special workplace for handling cassettes (storage, decontamination, reloading of used and fresh rolls of tape) significantly complicate the operation of the device.

The technical task of the claimed group of inventions is the creation of a device for automatic control of the removed radioactive contamination of the surface (SRZP) of fuel rods installed in the output control line of fuel rods.

The technical result, which directed the group of inventions, is a method and device for automatic control of SRZP fuel elements, providing:

- versatility of application according to the standard sizes of fuel rods;

- the required values of accuracy and performance of control of SRZP fuel;

- simplicity and reliability of the design of the device and control equipment;

- radiation safety and convenience of the staff.

To confirm the above, we present the description of the claimed method and the specific design of the device.

The claimed group of inventions is illustrated by the following drawings. FIG. 1 shows a general view of the device, FIG. 2 is a general view of the smear removal unit; FIG. 3 is a diagram of the phases of a twist of a fuel element with a sponge of a smear removal unit; FIG. 4 is a general view of the detection unit with a case of the reference measure; FIG. 5 - the case of the reference measure of α-activity, in FIG. 6 is a general view of the tape pedometer; FIG. 7 - an experimental sample of the device for checking decisions made.

A method of automatic control of the removed α-contamination of the fuel element surface is proposed, according to which the fuel rod is fed by any vehicle to the smear removal unit at the position of its surface contacting with fabric tape directed to the fuel element transversely to its axis, then the compacting surface of the fuel element is produced in the smear removing unit the tape, then the fuel rod is pulled through the smear removal unit, its compression is removed, then the tape with the smear obtained is moved along the guide rollers to the detected node at the specified step where the α-activity of the smear is recorded with a radiometer, then the level of removable α-contamination of the surface of the fuel element is determined by calculation and a signal is generated about the quality of the fuel element, moreover, rolls of tapes on the supply and reception coils of the fabric tape are replaced as necessary.

под детектор радиометра, выполняют измерение скорости счета n_сч от α-активности мазка, рассчитывают плотность потока α-частиц q с поверхности твэла S по формуле q=n_сч/(β * S * K), где K=K_к [1+λ*(F*F^-1 _к -1)], затем формируют признак качества твэла по условию: «Годен»: q≤q_nop * (1-0,5 δ_n), «Брак»: q>q_nор * (1-0,5 δ), где q_nop - пороговый уровень плотности потока α-частиц, равная 5 част/(см²мин), а δ - полная относительная погрешность измерения, равная 50% при Р=0,95 для пороговой плотности потока 5 част/(см²мин).It differs in that before the routine control procedure of the removed α-contamination of the surface of the fuel element, the radiometer sensitivity β is calibrated using a reference measure of α-activity embedded in the detector unit, a given friction force F _{k is set} , and the smear reduction factor to the force variation for friction λ, for the counting rate n, set the measurement time, based on a given statistical accuracy of measuring the counting rate and the ratio of the contact patch area on the smear to the cleaned surface of the fuel element , calibrate the coefficient of removal of the smear K _to the test samples with a known value of the removed α-contamination of the surface of the fuel rod (calibers); under normal control, the fuel elements are pulled forward with the lower tip through the compression zone, while controlling the sliding friction force on the crimped ribbon F, move the belt with a stroke to the step

under radiometer detector count rate measurement is performed by n _MF α-stroke activity is calculated flux density q α-particles from the surface of the fuel rod by the formula S = n q _MF / (β * S * K) , where K = K _k [1+ λ * (F * F ^-1 _to -1)], then form a quality sign of the fuel element according to the condition: "Good": q≤q _nop * (1-0.5 δ _n ), "Marriage": q> q _nor * (1-0.5 δ), where q _nop is the threshold level of the α-particle flux density, equal to 5 parts / (cm ² min), and δ is the total relative measurement error, equal to 50% at Р = 0.95 for the threshold flux density of 5 parts / (cm ² min).

An additional difference of the proposed method from the prototype:

мм, задаваемый в шагомере двумя полными оборотами счетного ролика, имеющего калиброванный диаметр d_poл, равный

, скорость перемещения ленты стабилизируют по результату измерения времени вращения счетного ролика на полный первый оборот путем регулирования угловой скорости шагового электропривода катушки намотки ленты с мазками по сигналу рассогласования ΔT=Т_з-Т_и, где Т_з и Т_и - заданный и измеренный периоды вращения ролика, соответственно, а расход ленты и ее остаток контролируют по выражению

, где L_ocm и L_иcx - остаточная и исходная длины ленты в рулоне, соответственно, n-зарегистрированное число снятых мазков,- tape with a stroke is moved to the step

mm, set in the pedometer by two full turns of the counting roller having a calibrated diameter d of the _circle equal to

, the speed of movement of the tape is stabilized by measuring the time of rotation of the counting roller for the full first turn by adjusting the angular speed of the stepper electric drive of the coil winding the tape with strokes by the error signal ΔT = T _c -T _i , where T _s and T _i are the specified and measured rotation periods roller, respectively, and the flow rate of the tape and its balance is controlled by the expression

where L _ocm and L and _cx are the residual and initial lengths of tape in a roll, respectively, n is the registered number of smears taken,

- if necessary, increase the performance of the control is combined in time of the operation of radiometry and smear removal, while providing the detector shielding from gamma neuron radiation coming from the controlled fuel element, and measuring the background count rate.

The method is carried out using the device (Fig. 1), containing a swab 2 removal unit, a smear 3 detecting node, a tape pedometer 4, a tape winding coil 5 and a tape winding coil with a stepper motor 6 mounted on a plate mounted on frame 1, mounted on frame 1 7 screen personnel protection against gamma-neutron radiation from a fuel element. The device works complete with radiometric equipment and a system of program-logic control.

, где шаг

- длина пути вращения на два оборота счетного ролика диаметром d_pол, a d_mв - диаметр твэла. (Пример, дано d_рол=20 мм, d_mв=6,9 мм и 10,5 мм, тогда длина шага

будет 2*π*20=125,6 мм, a L будет равно: для твэл БН с d_mв=6,9 мм - 114,8 мм, для твэл БРЕСТ с d_mв=10,5 мм - 109,1 мм).The node for removing the stroke 2 (Fig. 2) is an articulated-tongue tool consisting of an assembly of the joint 8 and two jaws 9 fixed on the force sensor 10. Compression / decompression of the jaws 9 is carried out by sequential activation of the pneumatic cylinders 11, which provides the required compression force of the fuel rod of any diameter (Fig. 3) and excludes a shear wave traveling along the tape to the smear detection unit and resulting in positioning errors due to the displacement of the tape. On the case of the hinge 8 is installed sensor the presence of a fuel rod 12, the signal which produces the operation of the compression of the fuel rod tape and relieve compression. The base of the force sensor 10 has fastening holes of longitudinal shape in the direction of movement of the tape. These slots are designed for precise installation adjustment of the distance L from the axis of the fuel element located in the swab 2 removal unit to the center of the receiving window of the detector 14. The size L is equal to

where step

- the length of the path of rotation for two turns of the counting roller with a diameter of _dpol , ad _mv is the diameter of a fuel rod. (An example is given for d _rol = 20 mm, d _mв = 6.9 mm and 10.5 mm, then the pitch length

will be 2 * π * 20 = 125.6 mm, a L will be equal: for _{TVN bn} with d _mv = 6.9 mm - 114.8 mm, for TVEL BREST with d _mv = 10.5 mm - 109.1 mm ).

Detection unit 3 (Fig. 4) contains α-particles detector 14 mounted on a shelf of bracket 13, case 15, in which a reference measure of α-activity (source 3П9) 17, a pneumatic actuator 18 for supplying a standard measure of α-activity is placed on a rectangular retractable plate 16 17 to the measurement position, the pneumatic actuator 19 for pressing a smear or a reference measure of α-activity 17 to the inner surface of the shelf of the bracket 13 having an opening for the passage of α-particles on the sensitive surface of the detector 14.

The pedometer tape 4 (Fig. 6) contains a counting roller 20, a presser roller 21 and an inductive sensor 22. The counting roller 20 has a hole on one flange through which the sensor 22 is triggered through each full turn (error of operation - no more than ± 0, 5 mm). The roller presser 21, presses the tape to the roller counting 20 in order to avoid slipping of the tape when sampling its free loop after removing the crimping of the fuel rod.

The inventive device works as follows: To begin, it is necessary to carry out certification of the measurement method, which is produced according to GOST R 8.563-2009 "Methods (methods) of measurement". When conducting certification using a standard measure of α-activity and calibers with a known value of the removed α-contamination of the surface S of a fuel element, determine the sensitivity of the detector to α-particles ε, the smear removal coefficient K _к , establish and control the friction force F _к , in the compression section of the fuel rod and rate sensitivity coefficient of friction to the smear removal force variations _to λ = δ / δ _F, where δ _k is the coefficient of variation of K the variation of friction force on the fuel rod wiping cloth tape δ _F, set speed measuring count time n _MF "obrabatyv calibration results and determine the measurement error of the particle flux density of the removed α-contamination of the fuel rod surface. Next, draw up a conclusion on the compliance of the method of monitoring SRSP fuel rods with the metrological requirements with the application of the results of theoretical and experimental research and certification certificate, and also approve the document governing the measurement methodology.

- TVEL serves the lower tip forward to the position of contact with a fabric tape directed to the fuel rod transverse to its axis;

- The sensor signal 12 provisions about the presence of a fuel element in the node removing the stroke 2 produce a dense compression of the surface of the tape using sponges 9 with a force that provides the sliding friction force of the fuel rod, installed during calibration by adjusting the pressure of compressed air supply pneumatic cylinders 11;

- Pull the fuel rod through the node removing the stroke 2 "through" with the measurement of friction force F by the force sensor 10, and get after cleaning the surface of the fuel rod S smear on the tape;

- Remove the compression tape ribbon of a fuel element on the signal of the position sensor 12 about the absence of a fuel rod in the node removing the stroke 2;

- Broach the tape on the step set by the pedometer 4, put a smear under the detector 14;

- Press pneumatic actuator 19 swab to the sensitive surface of the detector 14;

- Generate radiometer registered accounts n _MF speed calculated flux α-particles from the surface of the fuel rod by the formula q = q n _sch / (β * S * K) , where K = K _k [1 + λ * (F * F ^-1 _to -1)], and determine the quality of the fuel element by the condition: "Good": q≤q _nop * (1-0.5 δ _n ), "Marriage": q> q _nop * (1-0.5 δ), where q _nop is the threshold level of α-particle flux density equal to 5 parts / (cm ² min) and δ is the total relative measurement error equal to 50% at P = 0.95 for a threshold flux density of 5 parts / (cm ² min) ;

, где L_ocm и L_иcx - остаточная и исходная длины ленты в рулоне, соответственно, n - число снятых мазков;- Records the expenditure of the tape by the expression

where L _ocm and L and _cx are the residual and initial lengths of tape in a roll, respectively, n is the number of smears taken;

- At the command “end of the tape”, the control system lays a roll of fresh tape into the supply coil 5 and fastens the ends of the fresh and used tapes (for example, with clips), then pulls the tape together to put the ends of the clip into the area of the receiving coil 6, cut off the clean tape from the clip, and a roll of used tape with a clip is placed in a plastic bag and sent to the storage of solid radioactive waste (solid radioactive waste), after which the end of the fresh tape is fixed on the shaft of the receiving coil.

Distinctive features of the proposed method of automatic control of SRZP fuel rods, with the exception of indicators related to radiometry, were tested experimentally on the current layout shown in FIG. 7

Automation of the process of determining contamination is provided by a control system that is equipped with an autonomous system for collecting and archiving digital information, which allows storing data with reference to a fuel element number on the results of radiation monitoring. The specified amount of information allows an analysis of the technological process of manufacturing fuel rods.

Claims (8)

1. A method of automatic control of the removed alpha contamination of fuel rods, according to which the fuel rod is fed by means of a vehicle to the smear removal unit at the position of its surface contacting with fabric tape directed to the fuel element transversely to its axis, then, in the smear removal unit, the fuel surface is tightly compressed , then the fuel rod is pulled through the smear removal unit, its compression is removed, then the tape is moved with the received active contact patch on the smear along the guide rollers for a given step to the detecting unit where the α-activity of the contact patch on the smear is recorded with a radiometer, then determine the level of removed α-contamination of the fuel rod surface and form a signal about the quality of the fuel rod, in addition, they control the amount of tape consumed and, as necessary, replace the tape rolls at the feed and reception coils, characterized in that prior to the procedure of regular monitoring of the removed α-contamination of the fuel element surface, calibrate the sensitivity of the radiometer β by the reference measure of α-activity embedded in the node the detector, set the specified friction force F _to in the compression unit of the fuel element and the sensitivity index of the smear removal coefficient to the variation of the friction force λ, set the measurement time of the counting rate n _average based on the specified statistical accuracy of measuring the counting rate and area of the active contact spot on the smear, calibrate the removal coefficient K _to smear on test samples with a known quantity withdrawn α-pollution fuel rod surface (caliber), while normal control of fuel rods is pulled through compression zone, while controlling B fuel rod in the sliding friction of crimped ribbon F, after removal of the crimping stroke movement of the tape with a step

under the radiometer and measurements of the counting rate n _midrange from the α-activity of the contact patch on the smear, calculate the flux density of α-particles q, averaged over the wiped surface of the fuel rod, using the formula q = n _{mid frequency} / (β * K), where K = K _k [ 1 + λ * (F * F ¹ _to -1)]. 2. The method according to p. 1, characterized in that the quality attribute of a fuel element is determined by the condition: "Fit": q <q _nop * (1-0.5 <δ _n ), "Marriage": q> q _nop * (1-0 , 5 δ), where q _nop is the threshold level of the α-particle flux density, and δ is the total relative measurement error. 3. The method according to p. 1, characterized in that the movement of the tape on the step

ask for two full turns counting roller having a diameter

and the speed of movement of the tape is stabilized by measuring the rotation time of the counting roller for the full first turn by adjusting the angular speed of the stepper electric drive of the coil winding the tape roll with lubricants by the error signal ΔT = T _c - T _and , where T _s and T _i are the specified and measured periods of rotation on the first revolution, also the initial angular velocity of rotation of the stepper electric drive in each subsequent step

set by the result of the error signal compensation ΔT, obtained in the previous step. 4. The method according to p. 1, characterized in that the amount of tape consumed is controlled by the expression

where L _OST and L _Ref are the residual and initial lengths of the tape in a roll, respectively, n _{m is the} registered number of smears taken. 5. The method according to p. 1, characterized in that the coefficient of removal of the smear K _to apply in the form of the equality K _to = G * S _m , where G is the gamma adsorption of Gibbs. . 6. A process according to claim 1, characterized in that the active area of the smear spots S _m is of the S _m ^{=: π * k * d *} b, where k-fraction of the perimeter fuel rod crimped ribbon, d -dimetr fuel element, b- width tape, determined on the basis of a given statistical accuracy of measuring the count rate. 7. The method according to p. 1, characterized in that the replacement of the rolls of the wiping tape on the supply and the receiving coils is carried out by removing the remaining used wiping tape from the supply coil, laying the roll of fresh wiping tape into the supply coil, securing the end of the fresh tape to the end of the used tape, moving the clip of the ends of the cleaning tape to the take-up coil, cutting off the clean cleaning tape from the clip in the receiving coil, removing the roll of used cleaning tape together with the clip in the solid radio storage dry waste, fixing the end of a fresh wipe on the take-up reel shaft. 8. A device for carrying out the method, including a crimping mechanism for a fuel element with a fabric tape, feeding and receiving coils of a fabric tape, a mechanism for rotating the receiving coil, guide rollers, belt tensioners, a tape amount sensor, a detection unit, a radiometer and a software-logic control system, that the smear assembly is made in the form of an assembly consisting of a hinged-tongue tool, a beam-type strain gauge and two pneumatic cylinders for compressing and unclamping the jaws, feeding the coil of tissue tape and A multi-coil with a rotation mechanism is mounted on a bracket mounted on a shield of gamma-neutron radiation from a fuel rod, the detection unit is designed as an assembly containing an α-particle detector mounted on a shelf of a bearing bracket, a case with a reference measure of activity, a pneumatic actuator of a reference measure activity on the measurement position and pneumatic drive of the smear or reference measure to the inner surface of the shelf of the bearing bracket having an opening for the passage of α-particles on the sensitive surface d detector and the number of tape sensor is made in the form of a pedometer consisting of a counting roller with an outside calibrated diameter

roller pressure and inductive sensor control of the full revolutions of the roller counting.

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