Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
  • G01T7/00—Details of radiation-measuring instruments
  • G01T7/02—Collecting means for receiving or storing samples to be investigated and possibly directly transporting the samples to the measuring arrangement; particularly for investigating radioactive fluids
  • G01T7/04—Collecting means for receiving or storing samples to be investigated and possibly directly transporting the samples to the measuring arrangement; particularly for investigating radioactive fluids by filtration
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
  • G01N33/0093—Radioactive materials

Definitions

• the present invention relates to a system for collecting and using such a system for collecting radioactive aerosols present in at least one chamber.
• An enclosure may be a work room or a ventilation network.
• the technical field of the invention is in a nonlimiting manner that of monitoring an atmospheric contamination, radioactive or not, of an enclosure.
• a construction site tag such as the ABPM 203M product intended for the detection of ⁇ , ⁇ aerosols developed by the company Mirion Technologies is known.
• This construction tag conventionally comprises a collection head comprising a collection filter. Fluid flow is generated by suction means, causing particle deposition on the collection filter. A particle detector is arranged facing the collection filter. An output of the particle detector is coupled to an analog amplifier for sending an amplified signal to a device for processing the detected data.
• This construction tag is considered the closest according to the state of the art because it has a collection head separate from the suction means. That is, the collection head and the suction means do not form a non-deformable structural unit.
• This structure has the advantage of allowing precise positioning of the collection head and therefore close to the place where the fluid is analyzed.
• contamination of a collection head involves contamination of the suction means, as well as the amplifier,
• the signal must be amplified because there is attenuation thereof in the cable arranged between the processing device and the amplifier.
• This type of measurement chain does not make it possible to obtain the best performances, because this amplification degrades the signal / noise ratio.
• the detector can not be more than 10 meters away from the electronics for acquisition and signal processing.
• the object of the present invention is to solve at least one of the problems posed by the state of the art.
• each collection head comprising:
• a collection filter separating the collection chamber and the collection tube, the detector being arranged opposite the collection filter, the system further comprising a distribution box comprising suction means,
• each collection head being connected via its collection pipe to said distribution box by a sampling line, so as to allow a flow of fluid between the collection chamber of the collection head and the distribution box,
• the suction means being arranged to generate the flow of fluid between each collection chamber and the distribution cabinet.
• the detector may be disposed in a so-called detection chamber situated between the collection chamber and a chamber, called a chamber.
• electronics comprising a measurement electronics, electronically connected to an output of said detector and arranged to measure a radiation detection signal emitted by the detector.
• the detection chamber may further comprise a removable flexible lead sheet arranged to protect, with respect to gamma radiation. , a part of said detector.
• this collection head may further comprise at least one seal surrounding its detection chamber arranged to block the fluid from the side. of the collection chamber with respect to the detection chamber.
• the measurement electronics may comprise a digital acquisition electronics electronically connected to the output of the detector.
• the electronic chamber may further comprise data processing means connected to the digital data acquisition electronics and communication means. wired electronically connected to the data processing means.
• the measurement electronics can be removably connected to its detector.
• the system further comprises at least one air filter disposed on this sampling line between the collecting head of the collection head connected to this line. sample and the distribution box, arranged to trap at least a portion of the radioactive aerosols contained in the fluid stream.
• the distribution box may comprise at least one solenoid valve per sampling line, means for measuring a sampling rate at each solenoid valve and processing means configured to adjust a passage section of a solenoid valve in measurement function measured by said measuring means to ensure a flow of fluid at a constant rate, for at least one sampling line, preferably each sampling line, and / or the same flow rate for all sampling lines.
• At least one collecting head of the system according to the invention can be inside the at least one an enclosure and the distribution cabinet is outside the at least one enclosure.
• radioactive aerosols may be present in at least two enclosures and in that said system comprises at least two collection heads arranged in different enclosures.
• FIG. 1 is a front view and a sectional view of an embodiment of a collection head in a system according to the invention
• FIG. 2 is a diagram illustrating various components of the electronic chamber of the collection head illustrated in FIG. 1;
• FIG. 3 is a diagram illustrating a system according to the invention, implementing several heads of embodiment
• FIG. 4 is a diagram illustrating a distribution box implemented in the system according to the invention.
• FIG. 5 illustrates a second embodiment of a collection head in the system according to the invention, front view and sectional view.
• variants of the invention comprising only a selection of characteristics described subsequently isolated from the other characteristics described (even if this selection is isolated within a sentence comprising these other characteristics), if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.
• This selection comprises at least one feature preferably functional without structural details, or with only a part of the structural details if this part alone is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.
• the collection head of the system according to the invention constitutes in itself a patentable invention and could be the subject of a claim for the head itself in the set of claims.
• the collection head 100 comprises:
• the collection chamber is delimited by walls 112.
• the suction mouth 102 makes it possible to introduce a stream of air into the collection chamber 104.
• the air stream is then filtered by the collection filter 106 and leaves the collection head 100 via the collection tubing 108.
• the protective cap 110 is formed to protect the air vent 102 from larger particles.
• the protective cap 100 avoids sucking these larger particles and fouling the collection filter 106. This configuration promotes a better representation of the measurements on the collection filter 106.
• the detector 116 opens onto the collection chamber 104.
• the collection filter 106 separates the collection chamber 104 and the collection tube 108.
• the detector 116 is arranged opposite the collection filter 106.
• the detector 116 is disposed in a chamber 130, said detection.
• the detection chamber comprises an opening on which opens a detection surface of the detector 116.
• This detection chamber 130 is located between the collection chamber 104 and the electronic chamber 114, ie within the 100 collection head, the fluid could reach the electronic chamber 114 through the detection chamber 130.
• the detection chamber 130 further comprises a flexible lead sheet 124. This lead sheet is removable.
• the lead sheet 124 is arranged to protect, with respect to gamma radiation, a portion of the detector 116. It partially surrounds the detector 116.
• the collection head 100 further comprises a seal 126.
• the seal 126 surrounds the detection chamber.
• the seal 126 is arranged to lock the fluid on the side of the collection chamber 104 relative to the detection chamber 130. Thus, the fluid can not flow along the detector 116 to reach the electronic chamber 114.
• the air inlet portion of the collection chamber 104 located between the suction mouth 102 and the collection filter 106 makes it possible to reduce the aerosol velocity and to limit the impaction phenomena.
• the internal roughness of the collection chamber 104 is controlled to limit deposits and facilitate cleaning.
• the collection chamber 104 can separate from the detector 116, in order to promote the cleaning of the walls of the collection chamber 104.
• the detector 116 is based on scintillator technology.
• the advantage is in its value for money. Indeed, in comparison with silicon-type detectors, a scintillation detector makes it possible to obtain a larger useful surface area at a lower price than a silicon technology.
• a second advantage of using scintillation detectors is the ability to adapt the detector according to the need or the measurement environment. Thus, we can choose:
• a ZnS (Ag) scintillation detector which detects only the bone particles.
• a Phoswich type detector that is to say an assembly of a ZnS (Ag) detector, for the detection of the particles a, and a plastic detector for the detection of the ⁇ particles.
• the collection head 100 also comprises a closing / opening device 128 of the collection chamber 104 located at the suction mouth 102.
• a closing / opening device 128 of the collection chamber 104 located at the suction mouth 102.
• the device 128 allows, automatically, semi-automatic or manual, to block the inlet of the suction port 102.
• the electronic chamber 114 will now be described more precisely with reference to FIGS. 1 and 2.
• the electronic chamber 114 comprises a measurement electronics 118, electronically connected to an output of the detector 116.
• the measurement electronics 118 is arranged to measure a radiation detection signal emitted by the detector 116.
• the measurement electronics 118 is detachably connected to the detector 116. To do this, the measurement electronics 118 includes a 14-pin connector 120 for easy connection and disconnection of the electronics and detector.
• the measurement electronics 118 comprises a digital acquisition electronics 118a electronically connected to the output of the detector 116.
• the measurement electronics 118 further comprises data processing means 118b.
• the data processing means are connected to the digital data acquisition electronics.
• the electronic chamber 114 also comprises wired communication means 118c electronically connected to the data processing means. These wired means are of the Ethernet type.
• a system 500 according to the invention will now be described with reference to FIG. 3. The system according to the invention is used to collect radioactive aerosols present in an enclosure E.
• the system 500 comprises several collection heads 100a, 100b, 100c such as the collection head described with reference to FIGS. 1 and 2.
• the system 500 further comprises a distribution box 400 comprising suction means 404.
• the distribution box 400 is outside the enclosure E.
• Each collection head 100a, 100b, 100c is connected via its collection tube to the distribution box 400 by a sampling line, from in order to allow a flow of fluid between the collection chamber of this collection head 100a, 100b, 100c and the distribution box 400.
• the suction means 404 are arranged to generate the flow of fluid between each collection chamber and the distribution box 400.
• the system 500 further comprises at least one air filter (not shown) disposed on a sampling line between the collecting head of the collection head connected to this sampling line and the distribution box, arranged to trap at least one part of the radioactive aerosols contained in the fluid stream.
• the air filter avoids polluting the entire air line in case of contamination.
• the air filter is accessible and easily replaceable, of the type THE H 14 (for "Very High Efficiency", we speak in English of filter H EPA, for "High Efficiency Particulate Air [filter]”), that is to say that the minimum efficiency as a percentage of these filters is at least 99.995% in integral value, ie 99.975% in local value.
• the flow of fluid enters the collection chamber through the suction mouth, leaves this chamber through the collection filter, passes through the collection tube, the air filter, the sampling line and the box of distribution.
• the system 500 further comprises a supervision box 600, whose functions will be described in the following description.
• the distribution box 400 comprises:
• measuring means 408a, 408b, 408c of a flow rate are digital flowmeters
• processing means 410 which are a microcontroller
• the suction means 404 is a vacuum pump.
• the suction means could be a fan.
• the advantage of using such a pump is a long life of it. Note that there is a single pump for the entire system, which has the advantage of being less expensive that the maintenance of a pump by sampling head as in the prior art.
• the measuring means 408a, 408b, 408c of a sampling flow are located at each solenoid valve 406a, 406b and 406c.
• the processing means 410 are configured to adjust a passage section of a solenoid valve 406a, 406b, 406c as a function of measurements measured by the measuring means to ensure a real time constant flow of fluid for at least one sampling line 1a, 1b, 1c, preferably each sampling line, and / or the same flow rate for all the sampling lines.
• the supervisory cabinet 600 includes an industrial Panel-PC computer.
• the computer is waterproof to any aggression of liquids and dust.
• the screen is touch, the manipulation of the software is performed with the finger or with a stylus.
• the entire system 500 is computer controlled. The different features are:
• a second embodiment of a collection head 200 in the system according to the invention will now be described with reference to FIG.
• one or more collection heads 100a, 100b, 100c in the system 500 may be of the first or second embodiment of the invention.
• the collection head 200 comprises the same elements as the collection head 100. In particular, it is represented in FIG. Air 232.
• the air filter 232 is disposed on a sampling line downstream of the collection pipe of the collection head 200 connected to this sampling line.
• the air filter 232 is further disposed upstream of the distribution box 400, arranged to trap at least a portion of the radioactive aerosols contained in the fluid stream.
• the collection head 200 further comprises a device 234 for unrolling a film 216 on the collection filter of the collection head 200.
• the device 234 comprises rollers for unrolling the film 236.
• radioactive aerosols may be present in at least two enclosures and the system according to the invention comprise at least two collection heads arranged in the at least two different enclosures.
• a collection head and / or a system according to the invention for monitoring the contamination of nuclear site ventilation networks.
• the collection head is then connected to a sampling rod positioned inside a ventilation duct.

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• 2013
  • 2013-05-28 FR FR1354838A patent/FR3006446B1/fr active Active
• 2014
  • 2014-05-27 WO PCT/EP2014/060951 patent/WO2014191411A1/fr active Application Filing
  • 2014-05-27 EP EP14731919.8A patent/EP3004934A1/de not_active Withdrawn

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