The method of control and inspection of fuel elements

 

The method of control and inspection of fuel elements intended for use in the field of nuclear energy. The method includes a preliminary performance test-scanner. Also, there is a settingscanner and calibration byscan certified standard samples of enterprise - fuel elements with known parameters. Improved the accuracy of the control and inspection of fuel elements. 2 Il.

The invention relates to nuclear power and may find application in the manufacturing of fuel elements (FE) and build them into fuel assemblies (FA) for a nuclear reactor.

It is known that for the normal operation of a nuclear reactor, avoid distortions in the neutron and temperature fields in each of the fuel elements must be strictly specified number of nuclear fuel (fissile isotope) and uniform distribution along the length of a fuel rod. This must be provided and, as a rule, provided by the technology.

The equipment of the fuel Rods do pills uranium dioxide with strictly specified obese mass of fuel in the fuel element.

In addition, in some cases, the fuel is additionally determined by direct weighing. However, not excluded the cases falling into fuel elements under his rig fuel pellets with another enrichment of uranium 235, because in the process of manufacturing the fuel elements may be present fuel pellets with different enrichment of uranium 235, which outwardly from each other are no different. Given the importance of this characteristic of a fuel rod, it was necessary to control the fuel elements and their grading prior to Assembly in FA.

The known method of control and inspection of the fuel element, comprising the operations of loading and unloading the fuel elements and wiring them through the channel gamma scanner with a neutron source in a biological protection with submission of data in electronic computing machine (see book 2, “the Development, production and operation of the fuel rod power reactors” Ed. by F. G. Reshetnikov M.: Energoatomizdat, 1995, pages 284-285, Fig. 21, 14).

Controlled fuel rod is moved along the axis of the irradiator with a strictly constant speed. The inspection is carried out by trailing-radiation. The percentage of 235U is calculated 235U=e(N+a)/b, where N is the count rate, a and b are calibration constants.

The error in the determination of the content is in the range of 3-7% less than 5%. The inspection results are processed by computer and presented in the form of a Protocol. Monitored the fuel Rods of length 4 m and a diameter of-13,5 mm Wiring TVEL control and monitoring is carried out on the rollers, causing abrasion of the surface of the zirconium sheath of a fuel rod, which can lead to corrosive corrosion, resulting from the abrasion of Zirconia between the touching surfaces even in the absence of a corrosive environment (see “the metallurgy of zirconium”. The English translation edited by G. A. Meyerson, and Y. C. Gagarin M.: Publishing house of foreign literature, 1959, page 298).

Corrosive corrosion can lead to depressurization of the fuel rod in the core of a nuclear reactor.

The closest in technical essence and the achieved effect is a method of control and inspection of fuel elements for a nuclear reactor, including their loading, single-piece flow on an inclined table for connearney zirconium tape wiring fuel element through the channelscanner with a neutron source in a biological protection with data flow control in the electronic computer, sorting and unloading of fuel elements in decl is widelyused elements”).

In the technical solution of the prototype as a source of neutrons using Cf-252 with a nominal value of 1.2 mg as a neutron moderator beryllium moderator, and as biological shielding using lead.

To measure the gaps between the pellets of uranium dioxide and lengths of tablets in the fuel element using a densitometer to determine the presence of tabs in the fuel element using the detector, for controlling the trailing-radiation using a detector, consisting of eight BGO-scintillators, eight photomultiplier tubes with voltage dividers and eight fast preamplifiers (“NNC”) and the delayed neutron detector.

The method provides control of a fuel rod and defines the weight of the fuel column; 235U enrichment; fuel pellets with custom enrichment; the length of the fuel column; length compensation amount; gaps in the fuel column and the presence of tabs.

However, the method cannot guarantee the accuracy of control of a fuel rod without relevant technical characteristicsscanner, its configuration and calibration.

An object of the invention is to improve the accuracy of control and razbakov lowdelay elements for a nuclear reactor, including their loading, single-piece flow on an inclined table for connearney zirconium tape wiring fuel element through the channelscanner with a neutron source in a biological protection with data flow control in the electronic computer, sorting and unloading of fuel elements on inclined tables.

According to the invention carry out a preliminary performance testscanner, its setting and calibration by gamma scanning certified standard samples of enterprise-fuel elements with known parameters: class I:

the average enrichment in 235U fuel load;

- the length of the fuel column;

- the length of the fuel element;

- length compensation amount;

the presence and length of clips,

class II:

the average enrichment in 235U profiled zones;

the presence of the end plugs;

- the length of the profiled zones;

- average 235U enrichment zone,

class III:

- the presence of abnormal tablets enrichment in 235U in the Central part of the fuel column;

- the presence of abnormal tablets enrichment in 235U at the lower section of the fuel column;

the presence of nesthetic,

class IV:

the size of gaps in the fuel column;

- the location of the gaps;

the location and length of clips,

afterscan certified standard samples of enterprise - fuel elements with known parameters and compare them with the data issued by the electronic computing machine after-scan, decidescan regular batches of fuel elements with matching data, but with different data perform the tuningscanner in accordance with known certified standard samples of fuel elements in classes I-IV.

The proposed method allows to solve the technical problem to improve the accuracy of the control and inspection of fuel elements.

For explanation of the method of the drawings presents:

in Fig.1 - standard sample of enterprises (SOP) class I;

standard sample of enterprises (SOP) class II;

standard sample of enterprises (SOP) class III;

standard sample of enterprises (SOP) class IV;

in Fig.2 - installation-scan.

How is the ache on the inclined table 2 on connearney zirconium tape 3 wiring the fuel element 1 through channel 4scanner 5 source 6 neutrons in the biological protection 7 data flow control in the electronic computer 8, unloading fuel elements 1 on the inclined table 9 and rejection by an inclined table 10.

Beforescan regular batches of fuel elements 1 method involves a preliminary performance testscanner 5, configuration and calibration byscan certified standard samples of enterprise - fuel elements 11 with known parameters

class I:

the average enrichment of 235U fuel load;

the length L of the fuel element 11;

the length L1the fuel pole tablets 12;

the length L2the compensation amount;

the presence and length L3clamps 13,

class II:

the average enrichment in 235U profiled zones a, b, C, D, E different enrichment in 235U;

the presence of the end plugs 14, 15;

- the length of the profiled zones a, b, C, D, E;

the secondary enrichment zone 235U,

class III:

- the presence of abnormal tablets 12“and” enrichment of 235U in the Central part of the fuel column;

- the presence of abnormal tablets 12“in” bagamati fuel post;

- the location of individual abnormal tablets 12,

class IV:

the size of gaps in the fuel column;

- the location of the gaps;

the location and length L4clips,

comparison datascanning with known data certified standard samples of enterprises of the fuel elements 11 classes I-IV and the coincidence data issued by the electronic computing machine 8 after-scanning, data certified standard samples of fuel elements 11 implementation-scan fuel elements 1 of the regular parties, but with different data configurationscanner 5 in accordance with known certified standard samples of fuel elements 11 for class I-IV.

The method is as follows.

Pre-made standard samples of enterprises (SOP) - fuel elements 11 of the four classes, each of which serves to check the technical characteristicsscanner 5.

For a class I made two sets of “SOP”, each of which consists of four paddle performance testscanner 5 in operation and control “SOP”, used when there is suspicion of malfunction workers “SOP”. In the process of making “SOP” certified all of its parameters and entered into the passport.

Class II are four “SOP”, of which three workers and one control.

Profiled zones a, b, C, D, E, i.e., zones with different enrichment in 235U are certified and all parameters are entered in the passport.

Class III are two sets of three “SOP” to control and work “SOP” with the exact location of abnormal tablets 12 a, 12 C, 12“in”.

All parameters are entered in the passport.

Class IV made four “SOP”, of which one control with the use of the spring retainer. All parameters are entered in the passport.

The average 235U enrichment of the fuel load, the length of the fuel column, the length of the fuel element length compensation volume, presence and length of clips, the average enrichment in 235U shaped zones, the presence of the end plugs, the length of the profiled zones, the average enrichment in 235U shaped zone, the magnitude of the gaps in the fuel column, the location of the gaps, the location and length of the clips in the “SOP” determined sootvetstvuyuschego class “Sopa”.

During configurationscanner 5 will-scan Sopov I-IV class, and then compare the data of passports, “Sopov I-IV class with the data issued by the electronic computing machine 8.

The coincidence data exercisescan regular parties TVEL 1, and if not continue setting upscanner 5 “SOP” I-IV class.

Claims

The method of control and inspection of fuel elements for a nuclear reactor, including their loading, single-piece flow on an inclined table on a conveyor zirconium tape wiring fuel element through the channelscanner with a neutron source in a biological protection with data flow control in the electronic computer, sorting and unloading of fuel elements on inclined tables, characterized in that carry out a preliminary performance testscanner, its setting and calibration byscan certified standard samples of enterprises of the fuel elements in advance, and is of Alba;

the length of the fuel element;

the length compensation amount;

the presence and length of clips,

class II:

the average enrichment in 235U profiled zones;

the presence of the end plugs;

the length of the profiled zones;

average 235U enrichment zone,

class III:

the presence of abnormal tablets enrichment in 235U in the Central part of the fuel column;

the presence of abnormal tablets enrichment in 235U at the lower section of the fuel column;

the presence of abnormal tablets enrichment in 235U in the upper part of the fuel column;

the location of individual abnormal tablets,

class IV:

the size of gaps in the fuel column;

the location of the gaps;

the location and length of clips,

afterscan certified standard samples of enterprise - fuel elements with known parameters and their comparison with the data issued by the electronic computing machine after-scan, decidescan regular batches of fuel elements with matching data, but with different data perform the tuningscanner in accordance with known parameter

 

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