Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
  • G01K1/02—Means for indicating or recording specially adapted for thermometers
  • G01K1/026—Means for indicating or recording specially adapted for thermometers arrangements for monitoring a plurality of temperatures, e.g. by multiplexing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K9/00—Arc welding or cutting
  • B23K9/0026—Arc welding or cutting specially adapted for particular articles or work
  • B23K9/0035—Arc welding or cutting specially adapted for particular articles or work of thin articles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K9/00—Arc welding or cutting
  • B23K9/007—Spot arc welding
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
  • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
  • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
  • G01K7/04—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples the object to be measured not forming one of the thermoelectric materials
  • G01K7/06—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples the object to be measured not forming one of the thermoelectric materials the thermoelectric materials being arranged one within the other with the junction at one end exposed to the object, e.g. sheathed type
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C17/00—Monitoring; Testing ; Maintaining
  • G21C17/10—Structural combination of fuel element, control rod, reactor core, or moderator structure with sensitive instruments, e.g. for measuring radioactivity, strain
  • G21C17/112—Measuring temperature
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/30—Nuclear fission reactors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49002—Electrical device making
  • Y10T29/49117—Conductor or circuit manufacturing
  • Y10T29/49119—Brush

Definitions

• Temperature sensing device forming a thermometric rod, application to the electrical simulation of nuclear fuel rods
• the present invention relates to a new temperature sensing device, forming a multipoint type thermometer rod designed to detect temperatures at different points.
• the main application of the invention is the detection of the occurrence of the boiling crisis by means of an electrical simulation device of nuclear fuel rods intended to be assembled in assemblies by holding grids and intended for be used in so-called power reactors, especially those with pressurized water, (abbreviation in French REP or PWR in English).
• thermohydraulic qualification of the nuclear fuel rods in particular by detecting the occurrence of the boiling crisis of the liquid in which they are intended to be immersed under conditions representative of an operation. nuclear reactor.
• the occurrence and location of the boiling crisis must be detected in electrical simulation devices with response times enabling the activation of safety systems.
• the object of the invention is generally to detect, using a single device, temperatures at different points distributed along a plurality of axial and azimuth positions, in particular distributed at a high spatial density.
• the temperature detection device can be used to detect different temperatures or temperature gradients at different points of the same wall to be monitored, the temperatures at each point being detected. by thermal radiation.
• boiling crisis tests are required. More precisely, it is necessary to be able to detect the occurrence and location of the boiling crisis. Indeed, the boiling crisis can be defined generally as a significant excursion of wall temperature for a small variation of thermohydraulic control parameters. She is concretely translated by the abrupt degradation of the heat exchange between a heating wall and the heat transfer fluid which surrounds it, that is to say a sudden rise in wall temperature. Thus, in a PWR reactor, the occurrence of this phenomenon could lead to sheath failure of a nuclear fuel rod.
• nuclear fuel rod assemblies must be qualified with respect to the boiling crisis in order to assess the margins in nominal, incidental or transient pilotage operation, and to limit the risk of damage to fuel rods. rods that constitute the first fuel containment barrier.
• This qualification consists of experimentally defining the occurrence and localization of the boiling crisis by means of electrical simulation devices of nuclear fuel rod with a high thermal flux.
• the implementation of a simulation device consists, in quasi-permanent flow of the liquid in which it is immersed, to slowly evolve a single thermo-hydraulic parameter, while regulating the other parameters on predetermined fixed values, up to to reach the boiling crisis.
• the detection of the occurrence of the boiling crisis and its location require a high spatial density of measurement with very short response time constraints for safety and environmental constraints. very restricted access because of the very constitution of devices with small diameter tubes.
• the high spatial density of measurement is dictated by the high thermal flux with an axial profile generally non-uniform, imposed by the neutron.
• the grids have the same shape, dimensions and axial positions as those of an assembly in a reactor.
• thermocouples made of steel or another similar material are welded directly to the heating sheath at the points to be controlled, that is to say in areas where the crisis boiling is expected.
• the disadvantages of this technique are numerous and can be listed as follows:
• thermocouples in the indirect heating simulation device of the above-mentioned patent application FR 11 54336, the Applicant has proposed to insert each of a plurality of thermocouples in a groove formed on the outer periphery of the non-heating sheath and in direct contact with it. with the liquid to be heated, with the advantage of being able to position the thermocouples with great precision.
• the number of measurement points is still limited, the cost of achieving high measurement points, and there is still the disadvantage of the possible non-recovery of measurement instrumentation and instrumented ducts.
• Temperature sensing devices are also known, commonly known as multi-point thermometric / pyrometric rods which comprise temperature-sensitive elements, such as thermometric resistors, thermoelectric couples or thermistors, housed in a protective sheath. These thermometric rods have the advantage of being implanted in situ, of not physically impacting the object wall or walls on which the temperatures are detected and of being able to be recovered after measuring temperatures.
• thermometric rods do not allow for a very high spatial density, are relatively expensive and can not be implemented in areas where the available space, ie access is very restricted.
• the general object of the invention is therefore to provide a new temperature detection device that at least partially meets this need.
• a particular object of the invention is to propose a temperature detection device that can be used in an electrical simulation device of a nuclear fuel rod.
• thermometric rod a device for detecting temperature, forming a thermometric rod, comprising:
• the sheath is of a metal constituting one of the two metals of a thermocouple
• the sensing elements consist of a plurality of wires of a metal different from that of the sheath and constituting the other of the two metals.
• the invention consists in conferring on a sheath of a thermometric rod which has the function according to the prior art only to protect the elements sensitive, another function namely the function of a metal common to a plurality of thermocouples, the other metal of each of the thermocouples being that of a wire welded directly to the sheath, the wires being distributed in a plurality of axial positions and azimuths.
• the metal of the sheath is used as one of the two metals of a thermocouple and, as is common for all thermoblocks, a wall temperature is detected by thermal radiation at a given point by a only wire in the other metal of a thermocouple.
• thermometric rod according to the invention is, moreover, independent of the object to be monitored, it can as well as the objects to be monitored such as the heating sheaths of the electrical simulation devices, so be reused many times.
• thermometric rod according to the invention offers numerous advantages compared to the detection techniques according to the state of the art:
• thermometric rod and objects to be monitored such as heating ducts
• the metal of the sheath is a type K material.
• the metal of the wires is a type K material.
• the sheath is either chromel or nickel-chromium alloy, such as Inconel® 600, and son are alumel.
• Such type K thermocouples have the advantage of giving temperatures in a wide range and being of low cost.
• the son are covered with an electrical insulator except their junction ends.
• the alumel son are covered with a deposit of alumina.
• the thickness of the sheath is less than or equal to 0.1 mm.
• the outer diameter of the wires is less than or equal to 0.1 mm.
• the thermal inertia of a measuring point at the junction of a wire and the sheath is relatively low, which leads to relatively short response times. It is thus possible to detect the occurrence of the boiling crisis very quickly.
• the thermometric rod according to the invention it is possible thanks to the thermometric rod according to the invention to detect temperature variations above the determined detection threshold, typically greater than 10 ° C, in a time less than 100 ms. The boiling crisis in an electrical simulation device of a nuclear fuel rod is thus detected as soon as these temperature variations are greater than the determined threshold, at least equal to 10 ° C.
• the thermometric rod comprises at least one connecting tube made of the same metal as the sheath and of larger outer diameter than that of the sheath, the connecting tube being brazed around the sheath on the outlet side of the sheaths. metal wires. It is thus possible to make easier assembly of the thermometric rod in a heating sheath.
• thermometric rod which has just been described, comprising the following steps:
• Each metal wire can also be easily unrolled from conventional coils of a hundred meters of wire.
• the welding of one of the wire ends with at least one half-tube is performed by electric discharge.
• the reconstitution welding is performed by points. These well-controlled welding techniques allow the realization of very precise measurement junctions.
• the invention also relates in another aspect to a method of installing the temperature detection device which has just been described in an electrical simulation device of a nuclear fuel rod comprising at least one tube of electrically conductive material, said heating tube, for heating a liquid, in order to detect the occurrence of a boiling liquid crisis, in which the sheath forming the metal is arranged inside and away from the heating tube of the electrical simulation device common thermocouples, is filled with a pressurized insulating gas space between the sheath and the heating tube and is sealed the space filled with insulating gas pressurized.
• the remote arrangement is carried out by means of spacers of electrical insulating material, such as ceramic spacers, fixed on the outside of the sheath. housing the son welded and mounted playfully with the inside of the heating tube, in areas devoid of son.
• the clearance between spacers and the inside of the tube corresponds to a mounting clearance increased by a thermal expansion recovery set.
• a treatment of the inside of the heating tube and / or of the outside of the sheath is carried out beforehand so that it (them) to confer a thermal emissivity at least equal to 0,8.
• the treatment may advantageously consist of either a controlled oxidation treatment of the tube, preferably by heating in an oxidizing atmosphere, or a coating of a high thermal emissivity material, such as a black paint.
• thermometric rod according to the invention which has just been described installed according to the method described above to detect the occurrence of a boiling crisis.
• FIG. 1 is a schematic longitudinal sectional view of an electric simulation device of a direct-fired type nuclear fuel rod in which is installed a thermometer rod according to the invention
• FIG. 2 is a schematic longitudinal sectional view of an electric simulation device of a nuclear fuel rod type indirect heating in which is installed a thermometer rod according to the invention
• FIG. 3 is a schematic view showing in detail the thermometric rod according to the invention as it is installed in a direct-heating electrical simulation device according to FIG.
• The, 1 designate respectively:
• Lt overall length of the electrical simulation device
• Ln length of the device immersed in the liquid
• the mounting of the direct-fired electrical simulation device provides for immersing an electrical connection in the liquid at heat (Liq) while mounting an indirect heating electric simulation device (Figure 2) can not immerse any electrical connection, which is advantageous because there is no need to achieve a sophisticated electrical insulation by relation to the external environment.
• an electrical simulation device in which a thermometric rod is installed according to the invention is arranged within an assembly (not shown) of a plurality of identical devices with holding grids inside a tank (not shown) containing the liquid to be heated, the two electrical connections protruding from the tank being isolated therefrom by suitable means and the tubular resistor is supplied with direct current .
• the liquid to be heated is water.
• the liquid to be heated may be different.
• the liquid to be heated is sodium.
• heating length Le typically from 1 to 4.3 meters
• outer diameter outer sheath typically 8.5 to 10.7 mm
• the internal operating conditions of the electrical simulation device are as follows:
• FIG. 1 an electrical simulation device, usually called direct heating.
• the device 1 consists of a resistor 2 in the form of a tube which also serves as a sheath.
• the tubular sheath 2 also has the function of an electrical resistor, that is to say the part supplied with current to heat the liquid in which the device is immersed.
• the inside 20 of the tubular resistor / sheath 2 is filled with pressurized nitrogen.
• Two electrical connections 30, 31 are each fitted into one end of the sheath / resistor 2.
• connection 30 is that of supplying the current: it is pierced at its center to house the thermometric rod 4 according to the invention longitudinal axis X extending longitudinally along the axis of the device inside the heating sheath 2 in the space occupied by the pressurized insulating gas 20, as detailed below.
• connection 30 itself and by an end plug 5 of electrical insulating material.
• the other 31 of the connections is that of current output: it is full and therefore also serves as a sealing plug.
• FIG. 2 shows an indirect heating electric simulation device 1 as described and claimed in the patent application FR 11 54336. It consists essentially of:
• thermometric rod 4 installed inside the resistor 2 in the space occupied by the pressurized insulating gas 20.
• the power supply can be made in single-phase alternating current.
• FIG. 2 provides, as an electrically insulating and thermally conductive intermediate element, a column of pellets 6 made of ceramic material pierced at their center, stacked one on top of the other, and fitted around the tubular resistor 2 over its entire length. length and on a part of the electrical connections 30, 31.
• the temperature transient of the outer sheath wall 2, 7 is 1750 K / s with a margin of 300 K.
• the power supply power of the heating element 2 must be cut off with a characteristic decay time of less than 170 ms, which, given the characteristics of the power control, leaves the order of 100 ms for the time. detection characteristic.
• thermocouples for example at the number of eight sheathed type K thermocouples. in inconel 600, each arranged in contact with the outer sheath 2 or 7 in different axial and azimuthal positions at specified locations with a tolerance of +/- 2 mm.
• a direct heating device 1 similar to that shown in FIG. 1, the thermocouples were welded directly to the heating sheath 2.
• a device 1 with indirect heating similar to that described in the patent application FR 11 54336 and represented in FIG. 2, it has been planned to insert the thermocouples in grooves formed outside the sheath 7.
• thermocouples corresponded to areas in which the boiling crisis was likely to occur.
• the number of temperature detection points was thus limited, typically to about ten per device 1, essentially for reasons of relatively high costs in investment and labor. installation.
• thermometric rod 4 As shown in FIG. 1
• the rod 4 according to the invention comprises a protective sheath 40 made of a metal constituting one of the two metals of a thermocouple.
• a plurality of wires 4.1, 4.2, 4.3 made of a metal different from that of the sheath and constituting the other of the two metals of a thermocouple is housed inside the sheath 40.
• each of the wires 4.1, 4.2, 4.3 is welded inside the sheath forming a measuring junction of a given thermocouple, the soldered ends of the wires being distributed in a plurality of axial and azimuth positions relative to the X axis inside the sheath, each of the son coming out of the sheath by at least one of its ends.
• the metal of the protective sheath 40 and that of the wires 4.1, 4.2, 4.3 form type K thermocouples.
• the metal wires 4.1, 4.2, 4.3 are preferably covered with an electrical insulating coating in order to isolate them from each other and with respect to the sheath 40 (outside the junctions).
• the sheath is preferably in two parts 40, 41 with the larger one of larger diameter brazed around the lower one.
• the upper portion 41 thus constitutes a connection and allows easier mounting on the connection 30.
• thermometric rod 4 it is advantageous to proceed as follows: longitudinal cutting along two opposite generatrices of a tube 40 made of a metal constituting one of the two metals of a thermocouple, so as to form two half-tubes,
• thermometric rod To proceed with the assembly of the thermometric rod inside either the external heating sheath 2 (device 1 with direct heating of FIG. 1) or the internal resistor 2 (device 1 with indirect heating of FIG. inside and at a distance from this heating tube 2, the sheath 40 forming the common metal of the thermocouples, the space between the sheath and the heating tube is filled with a pressurized insulating gas 20 and a sealing of the space is achieved filled with insulating gas 20 pressurized by means of one or more electrically insulating elements 5.
• an electrically insulating element 5 such as a ceramic wedge
• a mechanical metal / metric connection can be made al between the connecting tube 41 and the tube 2 below the electrical insulating shim 5.
• the sheath 40 is provided with spacers or shims 8 of electrical insulating material, such as ceramics, in areas outside the measurement junctions. These shims 8 fixed on the outside of the sheath 40 are sized to be mounted with clearance with the inside of the heating tube 2. The clearance between shims 8 and the inside of the tube corresponds to a mounting set increased by one set thermal expansion recovery.
• the emissivity of the inner face of the heating tube 2 can be increased so as to be greater than a value of 0.8.
• the emissivity of the outer face of the sheath can be increased to a value greater than 0.8.
• thermometric rod according to the invention can be achieved in the upper part 41 of the thermometric rod according to the invention.
• outer sheath 2 or 7
• Thickness ⁇ 1mm with a value of 0.5mm at peak power flux equal to 3.5MW / m 2 ,
• Heating length Le 1 to 4.3 m
• Thickness about 2 mm
• thermometric rod 4 according to the invention
• Thickness 0.1 mm.
• shims 8 alumina or zirconia
• thermometric rod 4 according to the invention
• protective sheath 40 chromel or Inconel® 600,
• wires 4.1, 4.2, 4.3 alumina coated with alumina
• thermometric rod 4 With the dimensions and materials indicated for constituting the thermometric rod 4 according to the invention, the thermal inertia thereof is relatively low, which leads to relatively short response times. Typically, for a rise in temperature of the sheath 2 of 1000 ° C./s, a fixed detection threshold greater than 10 ° C. is crossed by the thermometric rod 4 in less than 100 ms for a sheath temperature 2 of less than 750 ° C. vs.
• the device according to the invention which has just been described in FIGS. 2 and 3 may just as easily constitute more generally to the temperature detection of a wall for which a high measurement density is required in the axial and azimuthal directions.

Landscapes

• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• General Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Monitoring And Testing Of Nuclear Reactors (AREA)
• Measuring Temperature Or Quantity Of Heat (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=47356204

Family Applications (1)

Country Status (6)

Cited By (2)

Families Citing this family (10)

Citations (1)

Family Cites Families (9)

• 2012
  • 2012-10-17 FR FR1259890A patent/FR2996914B1/fr active Active
• 2013
  • 2013-10-16 EP EP13818383.5A patent/EP2909592B1/fr not_active Not-in-force
  • 2013-10-16 US US14/436,508 patent/US9835497B2/en not_active Expired - Fee Related
  • 2013-10-16 WO PCT/IB2013/059395 patent/WO2014060966A2/fr not_active Ceased
  • 2013-10-16 JP JP2015537399A patent/JP2015536447A/ja active Pending
  • 2013-10-16 KR KR1020157010394A patent/KR20150065746A/ko not_active Withdrawn

Patent Citations (1)

Also Published As

Similar Documents

Legal Events