Alpha-Contamination Tester of Fuel Elements

Abstract

Tester for monitoring alpha contamination of fuel elements containing tandem loading module and unloading module of fuel elements, each having a fixed frame with cradles, position indicators of fuel elements, measurement module located between the loading module and unloading module, which includes the detection units of alpha radiation from the surface of fuel elements, pneumatic cylinders with position indicators of the rods for samples forwarding with the source of alpha radiation. The loading module is supplied with a movable automated carriage with cradles for forwarding fuel elements to the measurement module and then to the unloading module, besides the loading and unloading modules are provided with movable racks for placing the fuel elements on the cradles of the modules and carriage, and the samples with natural uranium isotopes are used as the source of alpha radiation for setup of the measurement module.

Claims

1. A fuel elements alpha-contamination tester, containing the fuel elements tandem loading module and unloading module, each of which includes a fixed frame with cradles, position sensors of fuel elements, measurement module located between the loading module and unloading module, which includes the detection units of alpha radiation from the surface of fuel elements, pneumatic cylinders with position sensors of rods for forwarding samples with source of alpha radiation, characterized in that the loading module is provided with movable automated carriage with cradles for forwarding fuel elements to the measurement module and thereafter to the unloading module, besides the loading and unloading module are equipped with movable racks for placing the fuel elements on the cradles of the modules and carriage, and the samples with natural uranium isotopes are used as the source of alpha radiation for adjustment of the measurement module.

2. The tester according to claim 1, the products flow distribution carried out by a corrector.

3. The tester according to claim 1, the carriage displacement by using a stepping motor with drive.

4. The tester according to claim 1, wherein the digital processing of the recorded alpha radiation from the surface of products is performed by using a summator, and the quick counting module as part of the industrial controller with output of the monitoring results to the operator panel.

5. The tester according to claim 1, wherein the detection units as part of the measurement module are covered against light by the protective shutters.

6. The tester according to claim 1, the processing of signals from the position indicators and transfer of control signals to all the actuating mechanisms by using a controller as the tester control system.

Description

EMBODIMENT OF THE INVENTION

[0012] The tester operates as follows.

[0013] The numbered products 34 with the previous process operation are input to the fixed frame with cradles 3 of the loading module 1, levelled with respect to the edge of the tester using an auto operator corrector 7 and are entered in the control system data base using the reader 2, subsequent displacements of the product on the fixed frame of the loading module is made using a movable rack 5 of the motor with drive 4 based on chain-drive until all the cradles on the fixed frame 3 shall not be filled, thereafter the accumulator of movable carriage with cradles 6 is filled using the movable rack 5, which includes the electromagnetic transducers 12, 14 for precise positioning relative to the loading module 1 with rack 22 lower position sensor, evacuation module 30 and measurement module 28, stepping motor 29 with drive displaces the carriage with products on the measurement module 28 up to the central position relative to the group of alpha radiation detection units 26, protected by customized screens 27 not allowing light contact with the fluorescent materials of the detection units, preliminary setup and calibration of the alpha-contamination tester of the product surface is made using pneumatic feed of the sample executed based on metal plates 25 with spraying of uranium radionuclides (.sup.234U, .sup.235U, .sup.238U), alpha radiation is recorded on irradiation of uranium dioxide radioactive dust on the surface of claddings following the recording of alpha radiation emanating from the surface of fuel elements, the tester shows the average alpha-activity of the mixture of uranium isotopes found on the product surface on the operator panel, Bq; average surface alpha-activity of the mixture of uranium isotopes on the product surface, Bq/cm.sup.2; mass of uranium-235 radionuclide on the product surface and referred to the area of its surface, enter the measurement results in the database with the characteristics of surface contamination of products having passed the test and correlated with their number, further displacement of the carriage with the products is made to the unloading module 30 at the expense of the carriage position detectors 17, 18 and product availability detectors on the unloading module 19, 20, unloading of the products on the fixed frame 31 of the module is made using the movable rack 32, rack 21 and drive 33 lower position sensor.

[0014] The operating principle of the tester on surface contamination measurement of the products consists in recording and recalculating the total flux of α-particles of the measured sample using the summator 24 and quick calculation module 35 as part of the controller 8 in the values of average alpha-activity of the mixture of uranium isotopes located on the product surface, Bq; average alpha-activity of the mixture of uranium isotopes located on the product surface, Bq/cm.sup.2; mass of uranium-235 radionuclide located on the product surface and relative to the area of its surface.

[0015] The tester allows determine the surface contamination of fuel elements with high efficiency and performance with highlighting of the metrological standardized characteristics of contamination with product yield to defective and usable by the testing levels, form database, providing reliability and safety during transportation of fuel elements as part of the automated production line of fuel elements, as well as transfer the obtained data to the operator panel without use of industrial computer as part of the device using automatic feed of reference blocks made of natural uranium isotopes.

BRIEF DESCRIPTION OF DRAWINGS

[0016] The schematic diagram of the tester is shown in FIG. 1.

[0017] The control system cabinet is shown in FIG. 2.

[0018] The complete functional chart of the proposed tester is shown in FIG. 3.