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EP-4741789-A1 - LEAK DETECTION DEVICE AND METHOD FOR A CONNECTION ASSEMBLY CONNECTING TWO HYDRAULIC MEMBERS DELIVERING MOLTEN SALTS

EP4741789A1EP 4741789 A1EP4741789 A1EP 4741789A1EP-4741789-A1

Abstract

Leak detection device for characterizing a fitting assembly (2) connecting two hydraulic elements together, with a test pipe (1) comprising a first dead-end portion (C1) and a second portion (C2) coupled to the first portion via the fitting assembly, the second portion of the pipe being pressurized under light gas, the test pipe containing a predetermined quantity of molten salts (SF), the device comprising a kinematic movement of the test pipe, movable between a first position (P1) in which the area of the fitting (Z2) is bathed by the molten salts contained in the test pipe and a second position (P2) in which the area of the fitting is not bathed by the molten salts, but subjected to the pressure of light gas, the device comprising a hermetically sealed enclosure (3) containing at least the fitting.

Inventors

  • RAME, Jérémy
  • Fricaudet, Matthieu
  • Jourdain, Erwan
  • Mirotta, Salvatore

Assignees

  • Naarea

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. Leak detection device (4) for characterizing a fitting assembly (2) connecting two hydraulic elements together, the device comprising a test pipeline (1) comprising a first dead-end portion (C1) and a second portion (C2) coupled to the first portion via the fitting assembly, the second portion of pipeline being connected to a light gas (GL) pressurization system by a light gas inlet (12), the test pipeline containing a predetermined quantity of molten salts (SF), the device comprising a kinematic of displacement of the test pipe, movable between a first position (P1) in which the area of the fitting (Z2) is bathed by the molten salts contained in the test pipe and a second position (P2) in which the area of the fitting is not bathed by the molten salts, but subjected to a pressure of light gas, with a continuous passage of gas from the light gas inlet (12) to the area of the fitting (Z2), the device comprising a hermetically sealed enclosure (3) enclosing at least the fitting (2).
  2. Detection device according to claim 1, wherein the two hydraulic elements are respectively two hydraulic lines (B1,B2).
  3. Detection device according to any one of claims 1 to 2, wherein the fitting is a flanged fitting (21,22).
  4. Detection device according to any one of claims 1 to 3, wherein the displacement kinematics is formed by a rotation, preferably with an angular stroke between 30° and 180° separating the first and second positions (P1,P2).
  5. Detection device according to any one of claims 1 to 4, wherein the hermetic enclosure (3) pivots with the test channel (1).
  6. Detection device according to any one of claims 1 to 5, wherein one or more pressure probes (44,45) are provided, the pressure in the test pipeline being controlled by control means (5).
  7. Detection device according to any one of claims 1 to 6, wherein one or more heating resistors (11,14) and one or more temperature probes (18,19) are provided, the temperature being controlled in the test pipe and/or the hermetically sealed enclosure via control means (5).
  8. A detection device according to any one of claims 1 to 7, wherein the leak detection device comprises a vacuum pump (63) for evacuating the hermetically sealed enclosure (3) in order to detect a possible presence of light gas by spectrometry.
  9. Detection device according to any one of claims 1 to 8, wherein the leak detection device further comprises a nitrogen reservoir (R2) and nitrogen is injected into the hermetically sealed enclosure outside of vacuum-pulling sequences.
  10. Detection device according to any one of claims 1 to 9, wherein the first portion comprises a reservoir-forming volume (42) to house the molten salts when the test pipe is in the second position (P2).
  11. Detection device according to any one of claims 1 to 10, wherein the temperature of the molten salts is between 450°C and 950°C.
  12. Leak detection method for characterizing a fitting assembly (2) connecting two hydraulic elements together, the device comprising a test pipeline (1) including a first dead-end portion (C1) and a second portion (C2) coupled to the first portion via the fitting assembly, the second pipeline portion being connected to a light gas (LG) pressurization system by a light gas inlet (12), the test pipeline containing a predetermined quantity of molten salts (SF), the device including a hermetically sealed enclosure (3) containing at least the fitting, the method comprising: a- to bring the test pipe, via a kinematic of the movement of the test pipe, into a first position (P1) in which the area of the fitting is bathed by the molten salts contained in the test pipe, c1- bring the test pipe into a second position (P2) in which the connection area is not bathed in molten salts, but subjected to light gas pressure, with a continuous passage from the light gas inlet to the connection area, c2- Pull the airtight vacuum chamber, c3- monitor for any appearance of light gas molecules in the airtight enclosure using a mass spectrometer.
  13. A detection method according to claim 12, wherein the temperature of the molten salts simulating normal service is between 450°C and 950°C, and the pressure in the test pipeline (1) is between 1 bar and 10 bar.
  14. A detection method according to any one of claims 12 to 13, wherein the hermetic enclosure (3) pivots with the test channel.
  15. A detection method according to any one of claims 12 to 14, wherein one or more temperature and/or pressure cycles are carried out.

Description

The present invention relates to a leak detection device for a fitting connecting two hydraulic elements, such as hydraulic lines. Particular interest is given to cases where lines and/or pipes carry physico-chemically aggressive liquids in operation, such as molten salts at high temperatures. The present invention also relates to a leak detection method for a fitting connecting two hydraulic lines, and more generally two hydraulic components containing a liquid containing molten salts. The hydraulic components may be lines, tanks, pumps, buffer vessels, filters, etc. The hydraulic lines of interest here are configured to convey a fluid, particularly a liquid, from one location to another within a facility that can be more or less complex. An example of a facility of interest here includes one or more fluid circuits ensuring fluid transport within a nuclear power plant. In a particular example, we are interested in pipes or conduits that transport a fluid of the molten salt type, at high temperatures which are typically in a range between 500°C and 950°C. When two pipes are connected to each other, a fitting with a sealing gasket is provided to prevent any leakage at that point. To properly compress the seal, a flanged assembly is usually used. A first flange presses against the back of a collar on a first pipe, and a second flange presses against the back of a collar on a second pipe. The flanges are tightened together, one towards the other, by a number of fastening means, such as bolts. This type of configuration is illustrated in the figure 1 . It is not excluded to use other types of mounting with for example a clamping sleeve or a system of collars. In the context of a nuclear energy installation, it is very important to ensure that the flanged connection system and the sealing gasket can provide the desired sealing performance throughout the life of the installation, without the possibility of dismantling the assembly thus formed. The present inventors are developing new solutions for so-called fourth-generation nuclear reactors based on molten salts, and they have designed a device and a method to be able to test a connection configuration joining two hydraulic elements, in particular two coupled pipes intended to convey a flow of molten salt liquid. To this end, a leak detection device is proposed to characterize a fitting assembly connecting two hydraulic elements together, the device comprising a test pipeline including a first dead-end section of pipeline and a second section of pipeline coupled to the first section via the fitting assembly, the second section of piping being connected to a system for putting into pressure under light gas through a light gas inlet the test pipe containing a predetermined quantity of molten salts, the device comprising a kinematic of displacement of the test pipe, movable between a first position in which the area of the fitting is bathed by the molten salts contained in the test pipe and a second position in which the area of the fitting is not bathed by the molten salts, but subjected to a pressure of light gas, with a continuous passage of gas from the light gas inlet to the area of the fitting, the device comprising a hermetically sealed enclosure containing at least the fitting. If there is a leak at the fitting, while the test pipe is in the second position, light gas will spread into the hermetically sealed enclosure, which has been previously evacuated, and the light gas can be detected, even in minute quantities, by means of a spectrometer such as is known in itself. Thanks to these provisions, it is possible to detect insufficient sealing performance at the connection, while keeping the assembly intact, i.e. without dismantling it. The detection device allows for tests, including cycling tests, that represent and simulate the lifespan of the fitting assembly. If a leak is detected, the proposed solution is modified, a new design is proposed, and a new test sequence is carried out with the new design, and so on until the solution is fully satisfactory. Advantageously, the light gas can be helium, which is a readily available gas. In other words, the leak detection device allows for the characterization of the fitting's sealing performance. A helium leak is detected using a mass spectrometer, enabling the detection of even the smallest amount of helium that has escaped through the fitting. The proposed test allows for a very precise characterization of the high-performance sealing requirements for the fitting assembly of interest here. The molten salts referred to here can be of any kind. It should be noted that the displacement method described in the invention can even be used for any type of liquid and any type of fitting assembly. It should be noted that in the first position, the connection area is entirely immersed in molten salts at the test pressure. The entire periphery of the seal and the fitting assembly is subjected to the physicochemical str