Remanufacturing
Remanufacturing and drop-in installation of a Catep-type angle drive for a PMC system - nuclear
Remanufacturing and drop-in of a CATEP-type right-angle gearbox for EDF – Fuel handling station loading machine at a nuclear power plant
Replace an angle drive with an identical one, in compliance with nuclear industry standards.
Guarantor of the nuclear safetyThe group EDF is legally responsible for the security of its facilities. Their teams had identified a suspicious noise on a angle drive operating on the fuel handling station by nuclear plantFuel handling is one of the most critical phases of a reactor outage. This is when the reactor core is opened to replace spent fuel assemblies with new ones. The need for deliver a new angle drive It was therefore vital. An additional problem immediately arose: the historical product is no longer manufactured.
They were looking for a solution to obtain strictly right-angle drives identically. In this complex quest, the EDF teams requested MERGER initially to obtain information on the equipment in power transmission other power plants and their application on the PMC systemsThe ability of our teams to provide a BPE plan, a complete quality file and manufacture a reducer that meets the conditions of use in the final environment (traceability, resistance to the environment, absence of backlash,etc…) finally convinced EDF's decision-makers to entrust us with the project.
The project, from remanufacturing for drop inThis concerned two angle drives delivered in two separate shipments. The first was delivered as quickly as possible to anticipate a production stoppage; the second is considered a emergency reducer for storage by theUTO (operational technical unit). Its purpose is to integrate the strategic stocksIf a gearbox breaks down at Cruas, Tricastin or Ambérieu en Bugey, the UTO must be able to deliver compliant equipment within a few hours. to avoid prolonging the shutdown of the power plant (which can cost millions of euros per day).
MdC, PMC, nuclear power plant: the use of the remanufactured angle return by merger
The fuel handling bridge (PMC) system
Le PMC is the set of equipment that allows the manipulation of fuel assemblies (AC) new or used. Its main function is to transfer the fuel between the reactor building (where the reactor vessel is located) and the spent fuel pool (where the fuel cools). The system must be of a reliability absolute because the fuel is extremely heavy, radioactive, and must remain submerged for cooling and radiological protection. The fuel arrives fresh at the Nuclear Auxiliary Building (BAN), is stored in a pool, and then transferred via a tunnel (the transfer tube) to the Reactor Building (RB).
The main equipment of PMC are: the loading machine (MdC) ACs in a tank located in the reactor building (BR), the AC transfer device between the reactor building pools and the combustible building (BK), the handling bridges on the BK side (auxiliary bridge and footbridge bridge).
La MdC (loading machine) is the application where the angle reference of this project. It's a telescopic overhead crane which moves above the reactor building (BR) pool. It consists of three main sub-assemblies where mechanical transmissions can be found:
- Le Bridge (Translation): It moves on rolling rails fixed to the walls of the pool (X-axis).
- Le Push Trolley (Direction) : Moves transversely across the bridge (Y axis).
- Le Telescopic mast and its grappling hook (Lifting): Go down into the tank to grasp the assembly (Z axis).
MERGER is very familiar with these systems lifting because the company has already supplied overhead crane manufacturers such as REEL, Joseph Paris et Eiffage for various nuclear power plants in France and abroad. In the turbine hall, in the reactor building or in ancillary areas, reducers et dimmers MERGER speed units are in operation on the current fleet.
The role of the MERGER angle drive (based on the CATEP model)
In this machine, the mechanics must be absolutely reliable. To be precise, the right-angle drive is not the machine performing the handling operation itself, but rather part of the system. systems complete considered as EIP includes an engine, some couplings, reducer, return corner, a drum for winding the cable and then the overhead crane on which this assembly is fixed.
The inspired angle bracket CATEP (a leading brand in the power transmission industry) remanufactured by MERGER plays a pivotal role:
-
Change of axis (the right-angle drive): At the top of the machine, space is limited. The motor is often mounted horizontally to save space. The right-angle drive CATEP allows this horizontal rotation to be transmitted towards a vertical axis.
-
Irreversivity and security: On some models, the type of gearing used in the equipment prevents the mast from suddenly falling back down due to gravity alone in the event of a power outage. It acts as a natural mechanical brake.
The CATEP boxes were chosen centrally for their robustness and their ability to maintain a very low mechanical play (backlash)In nuclear power, if the mechanism has too much "play", the position of the grapple at the bottom of the tank will not be precise, which is unacceptable.
Why are drop-in and remanufacturing the ideal solutions?
En nuclear plantThe equipment is rated for a specific lifespan. When the original model is no longer manufactured (obsolescence), a replacement is carried out. drop in with the imperative of maintaining an identical interface.
The new housing must therefore be fixed precisely onto the existing anchor points without drilling new holes. It must withstand the same loads and comply with the same standards. safety standards than the original. This avoids having to re-certify the entire bridge, which would cost millions of euros.
Le angle drive It is the "muscle" that transforms the engine's power into a precise and safe lifting movement. Without it, loading or unloading the reactor core would be impossible.
La remanufacturing Maintaining the same design therefore allows the plant's lifespan to be extended without altering the complex architecture of the handling station. What made the difference in this project was the ability to MERGER à provide detailed plans which can serve as reference for the plant's future similar needs.
Challenges and solutions provided by the remanufacturing of the angle drive
THEinstallation du fuel handling station (PMC), dating from the 80s, showed critical signs of obsolescence and mechanical deterioration. Everything was done quickly because theurgency du replacement was dictated by abnormal noises coming from the original angle drivesigns of a deterioration design progress. The client has therefore set a mandatory delivery date of 8 months from the date of the project validation IPSN either in August, a unique intervention window during which the installation was shut down.
Our teams (service) commercial et manufacturer) succeeded in carrying out a large-scale joint effort efficiency because of the lack of original technical documentation (plans and calculation notes) required a complete reverse engineering approach, itself punctuated by customer validation points.
MERGER has succeeded in designing a drop-in replacement solution with a placeholder mounting without any modification to the existing interface.
The new angle drive strictly respects the reduction ratio of 1/1 and supports a rotation speed of 2,000 rpm, conforming to the customer's specific requirement. To overcome the constraints related to weld inspections in a nuclear environment, the housing has been entirely carved from a solid block made from a single block of steel (monobloc), all painted with type paint PIC100approved for environments nuclearThe goal of the solution " drop in Merger's point is that the crown (lantern) and the flasks The new angle brackets should be exact copies of the old parts. CATEPThus, the fitter at the power plant site does not need to adapt the machine: he "installs and screws".
The remanufacturing of the angle drive and its stages
The documentary approach carried out by the design office and the sales department
MERGER has been able to integrate itself into an approach of nuclear safety cultureThe service included the provision of a complete quality file including the plan BPE (Good for Execution), the calculation notes and the a certificate in matters of moving parts (pinions, transmission shafts, gears, bearings) – CCPU according to standard NF EN 10204. This is an essential step because if, in 10 years, a defect is discovered in a batch of steel from a supplier, EDF can instantly find which power plants have reducers or right-angle drives made with the same batch thanks to the casting number (the "Heat Number").
Compliance with the list of manufacturing and control operations (LOFC) has, for its part, made it possible to guarantee the traceability total required by the sector. The LOFC links to the mobile material certificate; it contains the PV numbers (Minutes) of the materials used and allows verification that the manufacturing process respected the technical specifications client.
The workshop's expertise: the stages of remanufacturing
Once the design and machining phases were completed, three major phases required meticulous and rigorous work from the MERGER teams:
- Le heat treatment : Carburizing or nitriding to harden the surface of the teeth while keeping a soft core (to withstand shocks without breaking).
- La correction : Millimeter-precise finishing of the teeth to obtain a perfect surface finish.
- Le establishing and settings This is the phase where the mobiles are assembled in the casing and where the blueing is carried out.
Blue Belt and the results of a successful reverse engineering
La worn to blue took place during the final phase of the establishing, just before the closing definitive of sump and the oil filling. A manual operation performed by our most qualified mechanic/fitter, it consists of brushing the teeth du pinion with a dye (the Prussian blue), rotate thegear under load and observe the trace left by the contact on the driven wheel.
In this angle driveThe contact between the teeth must be perfectly centered to avoid mechanical problems (tooth breakage – fracture due to fatigue, vibration, or binding) with dramatic consequences. trace in blue allows us to visually confirm that the mechanical game is perfect.
THEgoal The priority was to maintain the entirety of the current system through a comprehensive service delivery of reverse engineering equipment for a discontinued (no longer manufactured) product, thus avoiding a replacement complete machine. Thanks to the precision of our solution “ drop in"The client was able to do it himself."on-site installation without requiring additional mechanical adjustments ("plug and play" hardware) and benefited from vital information to perform the same operations on the other angle drives of the PMC.
We are proud of this industrial success in reverse engineering because successfully completing all the steps (LOFC, material certificates, blueprinting) up to final delivery is a excellence exam for our teams.
TO GO FURTHER: Nuclear requirements
Working for the sector nuclear requires a Nuclear Safety Culture : a set of behaviors and attitudes that gives absolute priority to the protection of people and the environment. At mergersThis culture translates into a constant "questioning attitude", aimed at detecting and preventing any failure, error or attempt at counterfeiting/falsification (materials, certificates, signatures) from the design phase.
To understand our interventions in its strategic parks, here are the key terminological pillars of our business:
- Nuclear Safety Culture : Nuclear safety culture is defined by the International Atomic Energy Agency (IAEA) as the "set of characteristics and attitudes which, in organizations and individuals, cause issues relating to protection and security to receive, as an absolute priority, the attention they deserve because of their importance" The safety culture does not stop at the gates of the power plant. It is applied with the same rigor in our workshops during the manufacturing of each gear, because a failure in the factory can have repercussions years later during operation.
-
ASNR (Nuclear Safety and Radiation Protection Authority) : It is the sector's "controller." An independent body, theASNR It ensures, on behalf of the State, the control of nuclear safety and radiation protection to protect workers, patients, the public and the environment. It defines the guidelines for good practices to which our manufacturing processes conform.
-
IPSN (Important Nuclear Safety Case) : The case is closed. IPSN depending on the area where the equipment is located within the plant and the associated risk level. This classification triggers enhanced monitoring and control requirements throughout the project.
-
EIP (Element Important for Protection) It's the equipment itself, like our angle drive and a EIP is a component whose failure could compromise safety, health or the environment. Its compliance is a legal obligation.
-
AIP (Important Protection Activity) : These are all the crucial steps in our work (machining, heat treatment, blueing test). The realization of a AIP is entrusted exclusively to trained and sensitized personnel, because every technical action is a link in the overall safety chain.
