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CN-114556490-B - Maintenance device for fuel assembly and related assembly and maintenance method

CN114556490BCN 114556490 BCN114556490 BCN 114556490BCN-114556490-B

Abstract

The invention relates to a maintenance device (40) for a fuel assembly of a nuclear reactor, the assembly comprising-a plurality of guide tubes capable of each receiving a neutron absorbing rod and comprising at least one connection system, and-a tip end piece (16) defining a plurality of tubes (22) which are through and capable of receiving one of the connection systems of the guide tubes. The maintenance device (40) comprises-a tool (42) capable of locking or unlocking one of the guiding ducts with respect to the tip end piece by rotating the connection system (26) in the associated duct (22), and-a movable cover (44) capable of being arranged facing the tip end piece (16) and comprising a plate (54) defining at least one opening (56) capable of guiding said tool (42) to interface with the duct (22) associated with the connection system (26).

Inventors

  • Luc Bressos

Assignees

  • 法玛通公司

Dates

Publication Date
20260505
Application Date
20201014
Priority Date
20191014

Claims (9)

  1. 1. A maintenance device (40) for a fuel assembly (10) of a nuclear reactor, the fuel assembly (10) comprising: -a plurality of guide tubes (18), each guide tube (18) being able to receive a neutron absorbing rod and comprising at least one connection system (26) arranged at the end of the guide tube (18), and -A top end piece (16) defining a plurality of through ducts (22), each duct (22) being able to receive a connection system (26) of one of said guide tubes (18); characterized in that the maintenance device (40) comprises: -a tool (42) comprising an elongated body (46) along a main axis (B-B ') and capable of locking or unlocking at least one of the guide tubes (18) with respect to the tip end piece (16) by rotating a connection system (26) of the guide tubes (18) in the associated duct (22) about the main axis (B-B'), and A movable cover portion (44) which can be arranged facing the tip end piece (16) and which comprises a plate (54) defining at least one opening (56) which can guide the tool (42) into abutment with a duct (22) associated with the connection system (26), Wherein the tool (42) comprises a post (50) protruding transversely from the elongated body (46) with respect to the main axis (B-B ') and capable of limiting the translational movement of the tool (42) along the main axis (B-B') in the opening (56); And wherein the plate (54) comprises, for each opening (56), a stop (58) projecting radially from the plate (54) and extending over a portion of the periphery of the opening (56), the stop (58) being able to cooperate with the stud (50) of the tool (42) to limit the rotational movement of the tool (42) about the main axis (B-B').
  2. 2. Maintenance device (40) according to claim 1, wherein the elongated body (46) of the tool (42) has a hollow cylindrical end (51) defining at least one recess (52), and wherein the tool (42) comprises a centering rod (48) protruding outside the cylindrical end (51) along the main axis (B-B'), the recess (52) and the centering rod (48) being able to cooperate with one of the connection systems (26) to allow rotation of the connection system (26).
  3. 3. The maintenance device (40) of claim 1, wherein the plate (54) defines a slot (60) for each opening (56), the slot extending radially from the opening (56) and being configured to receive a post (50) of the tool (42).
  4. 4. The maintenance device (40) according to claim 1, wherein each stop block (58) extends over an angular range between 90 ° and 180 °.
  5. 5. An assembly, comprising: -a fuel assembly (10) of a nuclear reactor, the fuel assembly (10) comprising: +a plurality of guide tubes (18), each guide tube (18) being capable of receiving a neutron absorbing rod and comprising at least one connection system (26) arranged at an end of the guide tube (18), and A +tip end piece (16) defining a plurality of through-going conduits (22), each conduit (22) being able to receive a connection system (26) of one of said guide tubes (18); -a maintenance device (40) for the fuel assembly (10), the maintenance device being a maintenance device according to claim 1, the maintenance device (40) being configured to be transformed from a passive configuration, in which a tool (42) and a cover portion (44) are provided separate from the fuel assembly (10), to an active configuration, in which the cover portion (44) is provided facing the tip end piece (16) and the tool (42) cooperates with one of the connection systems (26) by being guided by an associated opening (56), Wherein the tool (42) comprises a post (50) protruding transversely from the elongated body (46) with respect to the main axis (B-B ') and capable of limiting the translational movement of the tool (42) along the main axis (B-B') in the opening (56); And wherein the plate (54) comprises, for each opening (56), a stop (58) projecting radially from the plate (54) and extending over a portion of the periphery of the opening (56), the stop (58) being able to cooperate with the stud (50) of the tool (42) to limit the rotational movement of the tool (42) about the main axis (B-B').
  6. 6. The assembly of claim 5, wherein the cover portion (44) includes an opening (56) for each guide tube (18), each opening (56) facing a conduit (22) associated with the guide tube (18) in the active configuration.
  7. 7. Assembly according to claim 5, wherein the connection system (26) is a collar comprising at least one boss (30) protruding transversely with respect to the guide tube (18), and wherein the tip end piece (16) defines a recess (23), the collar being transformable from a locked configuration, in which the recess (23) receives the boss (30) and prevents translational movement between the guide tube (18) and the conduit (22) along a main axis (B-B '), to an unlocked configuration, in which the boss (30) is separated from the recess (23), the tool (42) being able to transform the collar from one configuration to another by rotating the collar about the main axis (B-B').
  8. 8. The assembly of claim 7, wherein the tool (42) is capable of shifting the collar from one configuration to another by rotating the collar between 70 ° and 110 ° about the main axis (B-B').
  9. 9. A maintenance method implemented for an assembly, the assembly being in accordance with claim 5, the maintenance method comprising the steps of: -arranging the cover portion (44) facing the tip end piece (16) of the fuel assembly (10); -introducing the tool (42) into one of the openings (56) of the cover portion (44) and engaging the tool (42) with the corresponding guide tube (18), and -Rotating the connection system (26) of the guide tube (18) in the associated duct (22) and locking/unlocking the guide tube (18) with respect to the tip end piece (16).

Description

Maintenance device for fuel assembly and related assembly and maintenance method Technical Field The present invention relates to a maintenance device for a nuclear reactor fuel assembly. The invention also relates to a fuel assembly comprising a nuclear reactor and to an assembly of such maintenance devices. The invention also relates to a maintenance method for such an assembly. Background Specifically, the nuclear reactor is a pressurized water reactor (REP or english "pressurized water reactor" PWR). However, the invention is also applicable to fast neutron reactors. A nuclear reactor includes a core including a plurality of nuclear fuel assemblies juxtaposed in a vessel of the reactor. Each fuel assembly typically includes a nuclear fuel rod and a guide tube. The reactor further comprises control rods, each equipped with a plurality of absorption rods, which are arranged to be inserted into or withdrawn from the guide tube to control the reactivity of the reactor. When a maintenance operation is planned on the fuel assembly, such as replacement of a defective fuel rod, the tip end piece of the assembly needs to be removed. In particular, there is a need to unlock the connection system connecting the tip end piece and the guide tube. It is known to achieve this by means of a tool actuated by an operator under visual control by means of a camera. Since the assembly is underwater, the operator is more than 5 meters from the assembly. This operation is complex and time consuming to perform and can only be accomplished by highly skilled and trained operators. Thus, unlocking of the connection system is random, non-repetitive, and operator dependent. The same problem exists with the operation of locking the tip end piece after maintenance has been performed. Disclosure of Invention It is therefore an object of the present invention to propose a maintenance device which allows easy and quick locking/unlocking of the tip end piece, while ensuring good precision and repeatability. To this end, the invention relates to a maintenance device for a fuel assembly of a nuclear reactor, comprising a plurality of guide tubes, each of which is able to receive a neutron absorbing rod and comprises at least one connection system provided at the end of said guide tubes, and a top end piece defining a plurality of through ducts, each of which is able to receive a connection system of one of the guide tubes, the maintenance device comprising a tool comprising a body in the form of an elongated shape along a main axis and able to lock or unlock at least one guide tube relative to the top end piece by rotating the connection system of said guide tubes in the relative duct about the main axis, and a removable cover able to be provided facing the top end piece and comprising a plate delimiting at least one opening able to guide the tool into abutment with a duct associated with said connection system. Since the tool is guided by the cover portion, alignment of the tool with the guide tube is greatly facilitated, allowing locking/unlocking to be faster and more easily repeated without the need for a highly skilled operator. According to a particular embodiment, the maintenance device comprises one or more of the following features: The elongate body of the tool has a hollow cylindrical end defining at least one recess, and wherein the tool comprises a centring rod protruding outside the cylindrical end along the main axis, the recess and centring rod being able to cooperate with one of the connection systems to allow rotation of said connection system; the tool comprises a post protruding transversely from the elongated body with respect to the main axis and capable of limiting the translational movement of the tool along the main axis in the opening; For each opening, the plate comprises a stop projecting radially from the plate and extending over a portion of the periphery of the opening, the stop being able to cooperate with a stud of a tool to limit the rotational movement of said tool about the main axis, and For each opening, the plate defines a slot extending radially from the opening and capable of receiving a tool post block. The invention also relates to an assembly comprising a fuel assembly of a nuclear reactor, the fuel assembly comprising a plurality of guide tubes, each guide tube being able to receive a neutron absorbing rod and comprising at least one connection system provided at an end of the guide tube, and a tip end piece defining a plurality of through ducts, each duct being able to receive a connection system of one of the guide tubes, a maintenance device for maintaining the fuel assembly as described above, the maintenance device being configured to be transformed from a passive configuration, in which the tool and the cover are arranged separate from the fuel assembly, to an active configuration, in which the cover is arranged facing the tip end piece and the tool cooperates with one of the connection sy