摘要:
A mitigation assembly for a nuclear reactor including a box with an upper portion forming the head of the assembly housing an upper neutron shielding device, including a head including removable lock and a slug installed free to move in translation relative over a given travel distance, the lock being configured such that locking/unlocking between the head and the box can be made by displacement of the slug with an extraction grab with its pawls attached in the slug. The lower part of the upper neutron shielding device includes a cone-shaped sealing block with the tip of the cone oriented downwards, cooperating with a cone-shaped internal surface of the box, a sealing device being formed between the two, the assembly created forming a removable sealing plug.
摘要:
The main purpose of the invention is a mitigation assembly (40) for a nuclear reactor comprising a box (41) with an upper portion (41) forming the head of the assembly housing an upper neutron shielding (UNS) device, comprising a head (105) comprising removable locking means (100) and a slug (101) installed free to move in translation relative over a given travel distance, the locking means (100) being configured such that locking/unlocking between the head (105) and the box (41) can be made by displacement of the slug (101) by means of an extraction grab with its pawls attached in the slug (101), characterised in that the lower part of the upper neutron shielding device comprises a cone-shaped sealing block (107) with the tip of the cone oriented downwards, cooperating with a cone-shaped internal surface (108) of the box (41), a sealing device (109) being formed between the two, the assembly created forming a removable sealing plug (110).
摘要:
A system, method and apparatus for remotely installing a flange cover assembly on a fuel transfer tube fixed flange in a containment pit in a nuclear power plant is presented. In one example, the flange cover assembly includes J-bolt spring assemblies in which the feet of the J-bolt are rotated between a clamping and non-clamping orientation to engage with the rear face of the fixed flange. A tool frame is lowered into the containment pit to engage with the flange cover assembly to compress the J-bolt springs and extend the J-bolt foot toward and away from the flange cover. Dual acting cylinders move a spring compression frame on the frame tool to compress and relax the J-bolt spring assemblies.
摘要:
The method and the device are applicable to the penetrations (2) of a pressurised water nuclear reactor vessel head (1) during operation.The device includes a double circuit for picking off two gas samples (100, 16, 17; 12, 13, 14, 15) and a measurement assembly (18) which regularly compares the content, especially of water vapour, in the two samples picked off. The first sample is taken from the volume of a chamber (7) where the possible leak (10) emerges, and the second in proximity to the head (1) outside the region immediately affected by the leak. The assembly (18) makes it possible to generate (19) an alarm in the event of a leak and to distinguish it from operational alarms.Techniques and means are also provided for determining the flow rate of sweeping in the volume of the chamber (7) and for checking the pick-off and detection systems.
摘要:
A plug assembly for plugging the flow hole of a core support barrel employs an offset arm for securing the plug to the core support barrel above the flow hole and the adjacent thermal shield. The disclosed embodiments do not require the cutting of an access opening through the thermal shield.
摘要:
The plug (8) comprises a body in two parts (9, 10) in the form of flanges assembled together so as to be locked against rotation about their common axis and movable in axial translational motion relative to one another. A gasket (11) made of flexible material is inserted between the peripheral parts of the two flanges, and the flanges are axially clamped. The space (12) between the flanges (9, 10) can be evacuated before such clamping.
摘要:
A process for improving nozzles extending substantially vertically through openings in the head of a nuclear reactor and which are circumferentially welded to the head through a weld lying on an inner surface of the head and on the adjacent outer surface of the nozzle which comprises forming a coaxial, circumferential groove upwardly into at least a portion of the nozzle extending into the reactor and then filling the coaxial, circumferential groove with a weld material. The nuclear reactor head is also claimed.
摘要:
Apparatus for sealing the primary-side coolant flow nozzles of a nuclear steam generator. The steam generator has relatively small diameter manway openings for providing access to the interior of the steam generator including the inside surface of each nozzle, the manway openings having a diameter substantially less than the inside diameter of each nozzle. The apparatus includes a bracket having an outside surface for matingly sealingly engaging the inside surface of the nozzle. The bracket also has a plurality of openings longitudinally therethrough and a plurality of slots transversely therein in communication with each opening. A plurality of unitary plugs sized to pass through the manway opening are matingly sealingly disposed in each opening of the bracket for sealingly plugging each opening. Each plug includes a plurality of arms operable to engage the slots of the bracket for connecting each plug to the bracket, so that the nozzle is sealed as the plugs seal the openings and are connected to the bracket.
摘要:
Apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator. The invention includes an annular bracket sealingly attached to the rim of the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam that includes a first side section hingedly pivotably connected to a second side section for allowing the nozzle dam to be foldable. Removably connected to each side section is a center section, the center section and the side sections defining the generally circular nozzle dam for covering the opening defined by the annular bracket. The periphery portions of the center section and of the side sections have bores therethrough. A plurality of threaded bolts extend through the bores in the nozzle dam and into the threaded holes in the bracket for removably bolting the nozzle dam to the bracket. Interposed between the nozzle dam and the bracket is an elastomeric extrusion-resistant seal member having a plurality of apertures through the periphery thereof for receiving each bolt. As the nozzle dam is bolted to the bracket, a compressive force will act perpendicularly on the seal member. This compressive force will tend to cause the apertures of the seal member to extrude laterally outwardly away from each bolt, thus enlarging the aperture surrounding each bolt. Thus, the seal member is configured to effectively seal an imperfect seal surface and to resist extrusion such as by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is tightly bolted to the bracket. The extrusion-resistant feature of the seal member provides a nozzle dam that is fluid-tight because the aperture is not enlarged.
摘要:
A multisectioned nozzle dam (30) for use in a steam generator (24) with an integral bolt ring (32) has a body structure of general circular shape. Redundant seals including at least three separate inflatable peripheral seals (48, 50 and 52) with an alarm (A) for indicating a pressure increase between the second and third seals (50 and 52) is provided. Redundant supports including a plurality of independent bars (60, 62, 64 and 66) bolted to the integral bolt ring (36) secure the dam (30) within the nozzle (26) to the appropriate axial position.