- Email: [email protected]
Progress in the design of the ITER Neutral Beam cell Remote Handling System
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ARTICLE IN PRESS Fusion Engineering and Design xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
Progress in the design of the ITER Neutral Beam cell Remote Handling System R. Shuff a,∗ , M. Van Uffelen a , C. Damiani a , A. Tesini b , C.-H. Choi b , R. Meek c a b c
Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona, Spain ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance, France Oxford Technologies Limited, 7 Nuffield Way, Abingdon OX14 1RL, UK
a r t i c l e
i n f o
Article history: Received 16 September 2013 Received in revised form 16 January 2014 Accepted 16 January 2014 Available online xxx Keywords: F4E ITER Maintenance Neutral Beam Nuclear fusion Remote Handling
a b s t r a c t The ITER Neutral Beam cell will include a suite of Remote Handling equipment for maintenance tasks. This paper summarises the current status and recent developments in the design of the ITER Neutral Beam Remote Handling System. Its concept design was successfully completed in July 2012 by CCFE in the frame of a grant agreement with F4E, in collaboration with the ITER Organisation, including major systems like monorail crane, Beam Line Transporter, beam source equipment, upper port and neutron shield equipment and associated tooling. Research and development activities are now underway on the monorail crane radiation hardened on-board control system and first of a kind remote pipe and lip seal maintenance tooling for the beam line vessel, reported in this paper. © 2014 Elsevier B.V. All rights reserved.
1. Introduction The Neutral Beam Remote Handling System (NBRHS) will perform remote maintenance within the Neutral Beam (NB) cell, see Fig. 1, following the ITER nuclear phase when manned access will be limited due to neutron activation and contamination [1,2]. The NBRHS will be ready to perform scheduled and nonscheduled maintenance tasks on Heating Neutral Beam injectors (HNB), the Diagnostic Neutral Beam system (DNB) as well as neutron flux monitors and the vacuum-vessel in-service inspection system, all located in the NB cell. The NB cell, measuring 32 m by 48 m and spanning equatorial and upper level ports, will house two Heating Neutral Beam (HNB) injectors with the option to install a third, each delivering 16.5 MW and a Diagnostic Neutral Beam (DNB) system. HNB subsystems down-stream of the ion source and 1 MeV accelerator such as the Neutraliser, Residual Ion Dump (RID), Calorimeter and front end components, Fig. 2, will face highly challenging operating conditions composed of thermal loading of up to 10 MW/m2 and perturbations in beam focusing, potentially resulting in high power densities being dissipated in the components. Although routine replacement is not foreseen, it is expected that these components
∗ Corresponding author. Tel.: +34 934897573. E-mail address: [email protected] (R. Shuff).
could fail during the lifetime of ITER, resulting in loss of HNB performance, necessitating remote replacement. The NB Caesium ovens located in the Beam Source will require routine scheduled replacement and cleaning by remote means throughout the ITER operational lifetime. 2. NB maintenance tasks and equipment Experience from JET has proven that without a close collaborative design effort between reactor component designers and Remote Handling engineers, maintenance operations can range from proving impossible to perform, to highly costly and timeconsuming. Table 1 shows the current list of tasks around which the NBRHS concept design has been formed. The NBRHS design concept is mainly composed of movers, a manipulator and a range of tooling, listed in Table 2. 2.1. Monorail crane The NB cell monorail crane system (MCS) is the principal lifting and transportation device for equipment and components inside the NB cell, Fig. 3. A classical overhead bridge crane is not possible due to pillars, numerous feed-throughs in the cell ceiling, the limited height and available space in the cell. A fully remotely operated crane module travels on a monorail track with three branches serviced by switching mechanisms allowing positioning
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Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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R. Shuff et al. / Fusion Engineering and Design xxx (2014) xxx–xxx Table 2 Main NBRHS equipment. Equipment
Description
Monorail crane Beam Line Transporter Beam source equipment Beam line vessel top lid opening mechanism Rear flange opening mechanism Upper port RH equipment Neutron shield RH equipment
Movers
Bi-lateral, force reflecting servo-manipulator
Manipulator
Caesium oven tools Pipe maintenance tools Lip seal maintenance tools Bolting tools Cameras Vacuum cleaner Lifting adaptors
Tooling
Fig. 1. View of the Neutral Beam Cell and the ITER vacuum vessel.
enabling the crane to be lowered while still mounted on a small section of the monorail, prior to being transferred through the NB cell door into a transport cask. 2.2. Beam Line Transporter The NBRHS Beam Line Transporter (BLT) consists of a powered swung rail and a fixed rail attached to the building, an articulating boom, telescopic mast and manipulator to provide dexterous handling of tools, Fig. 4. Its function is to allow maintenance of beam line components and front end components during replacement operations such as:
Fig. 2. Side view of a HNB (right) and duct to the vessel (left).
of the crane along the beam axes of the DNB and two HNB systems [3]. Various lifting adaptors are used to accommodate unique component geometries and specific transportation path requirements. Motorised twist locks are used as a standard interface fixture between the monorail crane, lifting adaptor and component. The monorail crane can be removed from the NB cell for maintenance or storage using the permanently installed transfer hoist, Table 1 Main NBRHS tasks. Maintenance task
Description
Caesium oven replacement Caesium oven cleaning Beam source Neutraliser Residual Ion Dump
RH class 1 Scheduled replacement RH class 2 Replacement upon failure Estimated failure probability: >0.3 in 20-year period
Calorimeter Fast shutter mechanism NB top lid NB rear flange Active control coils Exit scraper Passive magnetic shield Neutron shield Absolute valve Fast shutter NB cryopump High voltage bushing Upper port diagnostics Neutron flux monitor VV in-service inspection
• Cutting and re-welding of water cooling pipes and other services. • Cutting and re-welding lip-seals during opening/closing of the beam line vessel top lid and beam source vessel rear flange. • Bolting operations during opening and closing of lid and flange and replacement of components. The articulating boom and telescopic mast form one portable module that can be deployed at each of the swung rails of the respective beam line, thereby minimising duplication of equipment. In the current concept only one manipulator is present in the NB cell, which will be confirmed after the operation efficiency and rescue assessment in the next design phases. This manipulator can similarly be interchanged between various locations inside the NB cell, including the Beam Line Transporter and the beam source
RH class 3 Replacement upon failure Estimated failure probability >0.03 in 20-year period
Fig. 3. Monorail crane system, transporting a calorimeter with a generic lifting adaptor (exploded view).
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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Fig. 4. Beam Line Transporter accessing internal components whilst the top lid is lifted in its vertical position.
equipment, locating with a universal manipulator connector, transported by the monorail crane. The complementary services are provided by the service modules containing the local liquid and gas supplies, etc., which are also deployed with the monorail crane. Access to the Beam Line components is enabled by the sequential removal of the upper active correction and control coils, the upper segmented passive magnetic shield plates, and finally the Beam line vessel top lid. This requires unbolting of a rigid structural flange 3.5 m in length by 9.5 m in breath, then cutting (and subsequent re-welding on replacement) of a lip weld of the same nominal dimensions performing vacuum and confinement functions. Weighing 16 tonnes the top lid is lifted clear of the vessel using the top lid opening mechanism, a dedicated lifting device mounted on an adjacent pillar. Standard twist locks are used to connect the opening mechanism with the lid. 2.3. Beam source equipment Maintenance of the Caesium oven and Beam Source is performed by the NBRHS beam source equipment, Fig. 5, consisting of a support frame, a carriage, mast, articulated boom, manipulator, extension rails and a source carriage. The Beam Source is accessed via the Beam Source Vessel (BSV) rear flange after lowering the rear PMS plate, where tools for unbolting of the flange and cutting/rewelding of the lip seal are deployed. The Caesium ovens of the beam source are accessible through a small hinged door within the rear
PMS plate, in order to limit radiation levels during this scheduled maintenance. During opening, the rear flange is supported and repositioned by the BSV rear flange equipment. Similar in principle to the top lid opening mechanism, the BSV rear flange equipment is permanently installed in the NB cell. It engages with the rear flange on dowels and is locked in place by motorised bolts. Once open, all service connections and mounting fixtures are removed, and the Beam source is moved outside the vessel using the source carriage moving on the extension rails, where it can be collected by the monorail crane. 2.4. Manipulator A force reflecting, bi-lateral servo manipulator is foreseen for the NB cell, providing dexterous manipulation of tooling and discrete components. Using a common mating connector providing structural support, locking and all necessary service connections, the manipulator can be transported between locations, including the Beam Line Transporters, the beam source and upper port equipment. The concept design is based on a two arm manipulator with 50 kg lifting capacity and an additional 100 kg lifting capacity chest mounted winch, like the one presently operated at JET. 2.5. Tools A suite of generic and special tooling is foreseen for the over 70 individual components requiring remote maintenance within the NB cell, to support the various alignment, cutting, cleaning, welding and inspection tasks adapted to the different dimensions of the service connections.
Fig. 5. Beam source equipment maintaining the beam source (rear PMS plate underneath not shown here).
2.5.1. Pipe tooling Water cooling pipes for beam line components must be cut and re-welded during replacement operations. Designed for RH deployment with a manipulator, the Removable Bellows Assembly (RBA), Fig. 6, is a novel and flexible means to create a generous assembly clearance between beam line components being removed and the remaining plant components. Remote metrology of the cut pipe ends is made prior to installation of the RBA to determine any misalignment between pipe stubs. A bespoke replacement bellows section can then be prepared to ensure an optimal fit. Fine adjustment can also be made by manipulating the RBA pipe alignment
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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Fig. 8. Lip seal welding tool.
Flange bolting, lip cutting, welding and inspection tools are deployed on trolleys, guided by a rail running next to the flange and lip, Fig. 8.
Fig. 6. Removable bellows assembly.
tools to satisfy the fit-up tolerance necessary for orbital TIG welding. The pipe alignment tools also offer a common mounting slot for orbital cutting, welding and inspection tools, Fig. 7. 2.5.2. Flange tooling The NB system top lid, rear flange and front end components feature a lip seal that is cut and subsequently re-welded during RH interventions. The lip seal is a partial penetration weld suitable as a vacuum and confinement barrier, while structural loading is borne by a rigid bolted flange, isolating the lip from stresses.
2.5.3. Bolt tooling A set of standard RH bolting tools based on IO’s RH standards and bespoke tools have been outlined. • Torque multiplying bolt runners, originally developed at JET, driven by the manipulator gripper giving the operator tactile sensing feedback during bolting, for a M12–M36 bolt sizes. • Powered torque tools, for M12–M36 of bolt sizes. • Lay shaft and lay shaft tools, i.e. long reach tool for difficult to access bolts, such as those fixing the beam line vessel components to their supporting beds. RH standard captive bolts are used, holding the bolt in place on the component after thread disengagement. 3. Neutral Beam Remote Handling system R&D activities During the Neutral Beam Remote Handling concept design phase a number of research and development needs were identified. These include on board control and communications for the monorail crane and remote cutting, re-welding and inspection of pipes and lip seals. F4E is proceeding with these tasks to further establish the technical feasibility of the Remote Handling system prior to continuing design and production of the complete NBRHS with the industrial suppliers during the next to come procurement phase. 3.1. Monorail crane on-board control system development
Fig. 7. Deployment of pipe tooling.
For RH equipment operating on activated structures, radiation sensitive electronics such as motion controllers and other integrated electronics are strictly located away from the work area in shielded locations. Every effort is made to ensure only the bare minimum of vulnerable components are placed in the field such as actuators and diagnostics serviced by umbilical. In the case of the monorail crane, due to the length and circuitous routing of the rail a classical umbilical is not technically feasible. Alternative solutions have been considered such as CAN bus communications using dedicated additional bars in the monorail conductor rail, however this system suffers from susceptibility
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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to noise and low bandwidth, preventing transmission of camera data for example. Discrete plug-in points again using a dedicated communications rail on the monorail conductor bar could allow the crane to move up to a few metres in either direction whilst plugged in, however a dedicated plug-in mechanism and numerous plug in points at short intervals would be required. The preferred solution uses wireless transmission in parallel with CAN bus communications to communicate operator commands to a control system located on-board the monorail crane. Such a system would necessitate potentially sensitive electronics such as a wireless transceiver, real-time motion control processor along with actuator drivers, all working in a ␥ environment. A R&D activity is being carried out by F4E’s engineering support supplier Oxford Technologies Ltd. to identify commercial off the shelf (COTS) components for the monorail crane on-board control unit capable of tolerating the radiological conditions inside the NB cell during shut down. The crane design features an estimated 40 actuators including: locomotion motors, lifting drum motors, brakes and twist lock actuators, all to be serviced by the on-board control unit. In addition an estimated 81 sensors such as resolvers, multiple limit switches, a load cell and a camera will also interface with the controller. Other necessary on-board functionality includes: remotely resettable circuit breakers, fire detection, on-board radiation monitoring, temperature control and emergency stop. Components operating in the NB cell during shutdown only are required to have a minimum radiation life time of 20 kGy equating to 119 weeks full time operation at the maximum expected dose rate of 1 Gy/h. A total of 243 on-board electrical components were identified during the study, occupying a volume of 225 l, requiring a total of 600 wires. Given the available volumes for control elements, a realistic thickness of lead shielding yields a minimum radiation hardness target of only 1 kGy, though this remains to be verified against the resulting extra loading during seismic events. COTS components for all necessary processors such as: motion controllers, resolvers, I/O processing and load cell were successfully found rated at 1 kGy, most of them being developed previously for space applications. No suitable actuator drivers could be identified, requiring adaptation with radiation hard subcomponents and possibly radiation testing. Similarly power supplies, accelerometer, cooling and fire detection units could not be identified with adequate radiation tolerance. 3.2. Pipe and lip seal maintenance
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conditions. UHV class welding and cutting are highly skilled tasks and demand the precise control of parameters such as metallurgic composition, component geometry, joint fit-up and tool placement to give some examples. Remote Handling deployment of tools implies limited dexterity, limited vision and reduced manoeuvrability compared to a skilled human operator. Special considerations in the design of RH cutting/welding tooling must therefore be made together with rigorous mock-up testing in order to ensure the consistent creation of the optimum joint. The implications of a failure in either the tooling or the finished joint are serious; this together with the first of a kind deployment of such tooling has stimulated an R&D activity due to commence in the latter half of 2013. Prototype proof-of-principle lip and orbital pipe cutting and welding tools along with support tools such as alignment will be developed and tested in parametric conditions. Results will be used as input for the industrial supply of the NBRHS. 4. Conclusion The conceptual design of the NBRHS has been successfully defined. As part of this process, specific technology needs have been identified, such as radiation tolerant components for the monorail crane on-board control system and remote cutting and welding of pipes and lip seals. R&D activities are underway on both topics with the aim of reducing both technological and managerial risks in the final industrial supply. Disclaimer The views expressed in this publication are the sole responsibility of the authors and do not necessarily reflect those of the ITER Organization or Fusion for Energy. Neither Fusion for Energy nor any person acting on behalf of Fusion for Energy is responsible for the use which might be made of the information in this publication. References [1] C.-H. Choi, J. Palmer, C. Conesa, J.-P. Friconneau, J.-P. Martins, R. Subramanian, et al., Remote Handling concept for the neutral beam system, Fusion Engineering and Design 86 (2011) 2025–2028. [2] N. Sykes, C. Belcher, C.-H. Choi, O. Crofts, R. Crowe, C. Damiani, et al., Status of ITER neutral beam cell remote handling system, Fusion Engineering and Design 88 (9–10) (2013) 2043–2047. [3] O. Crofts, P. Allan, J. Raimbach, A. Tesini, C.-H. Choi, C. Damiani, et al., Applying remote handling attributes to the ITER neutral beam cell monorail crane, Fusion Engineering and Design 88 (9–10) (2013) 2057–2061.
ITER will be the first nuclear installation where welding and cutting of pipes and lip seals are performed routinely under RH
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
ARTICLE IN PRESS Fusion Engineering and Design xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
Progress in the design of the ITER Neutral Beam cell Remote Handling System R. Shuff a,∗ , M. Van Uffelen a , C. Damiani a , A. Tesini b , C.-H. Choi b , R. Meek c a b c
Fusion for Energy, Torres Diagonal Litoral B3, Josep Pla 2, 08019 Barcelona, Spain ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul-lez-Durance, France Oxford Technologies Limited, 7 Nuffield Way, Abingdon OX14 1RL, UK
a r t i c l e
i n f o
Article history: Received 16 September 2013 Received in revised form 16 January 2014 Accepted 16 January 2014 Available online xxx Keywords: F4E ITER Maintenance Neutral Beam Nuclear fusion Remote Handling
a b s t r a c t The ITER Neutral Beam cell will include a suite of Remote Handling equipment for maintenance tasks. This paper summarises the current status and recent developments in the design of the ITER Neutral Beam Remote Handling System. Its concept design was successfully completed in July 2012 by CCFE in the frame of a grant agreement with F4E, in collaboration with the ITER Organisation, including major systems like monorail crane, Beam Line Transporter, beam source equipment, upper port and neutron shield equipment and associated tooling. Research and development activities are now underway on the monorail crane radiation hardened on-board control system and first of a kind remote pipe and lip seal maintenance tooling for the beam line vessel, reported in this paper. © 2014 Elsevier B.V. All rights reserved.
1. Introduction The Neutral Beam Remote Handling System (NBRHS) will perform remote maintenance within the Neutral Beam (NB) cell, see Fig. 1, following the ITER nuclear phase when manned access will be limited due to neutron activation and contamination [1,2]. The NBRHS will be ready to perform scheduled and nonscheduled maintenance tasks on Heating Neutral Beam injectors (HNB), the Diagnostic Neutral Beam system (DNB) as well as neutron flux monitors and the vacuum-vessel in-service inspection system, all located in the NB cell. The NB cell, measuring 32 m by 48 m and spanning equatorial and upper level ports, will house two Heating Neutral Beam (HNB) injectors with the option to install a third, each delivering 16.5 MW and a Diagnostic Neutral Beam (DNB) system. HNB subsystems down-stream of the ion source and 1 MeV accelerator such as the Neutraliser, Residual Ion Dump (RID), Calorimeter and front end components, Fig. 2, will face highly challenging operating conditions composed of thermal loading of up to 10 MW/m2 and perturbations in beam focusing, potentially resulting in high power densities being dissipated in the components. Although routine replacement is not foreseen, it is expected that these components
∗ Corresponding author. Tel.: +34 934897573. E-mail address: [email protected] (R. Shuff).
could fail during the lifetime of ITER, resulting in loss of HNB performance, necessitating remote replacement. The NB Caesium ovens located in the Beam Source will require routine scheduled replacement and cleaning by remote means throughout the ITER operational lifetime. 2. NB maintenance tasks and equipment Experience from JET has proven that without a close collaborative design effort between reactor component designers and Remote Handling engineers, maintenance operations can range from proving impossible to perform, to highly costly and timeconsuming. Table 1 shows the current list of tasks around which the NBRHS concept design has been formed. The NBRHS design concept is mainly composed of movers, a manipulator and a range of tooling, listed in Table 2. 2.1. Monorail crane The NB cell monorail crane system (MCS) is the principal lifting and transportation device for equipment and components inside the NB cell, Fig. 3. A classical overhead bridge crane is not possible due to pillars, numerous feed-throughs in the cell ceiling, the limited height and available space in the cell. A fully remotely operated crane module travels on a monorail track with three branches serviced by switching mechanisms allowing positioning
0920-3796/$ – see front matter © 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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R. Shuff et al. / Fusion Engineering and Design xxx (2014) xxx–xxx Table 2 Main NBRHS equipment. Equipment
Description
Monorail crane Beam Line Transporter Beam source equipment Beam line vessel top lid opening mechanism Rear flange opening mechanism Upper port RH equipment Neutron shield RH equipment
Movers
Bi-lateral, force reflecting servo-manipulator
Manipulator
Caesium oven tools Pipe maintenance tools Lip seal maintenance tools Bolting tools Cameras Vacuum cleaner Lifting adaptors
Tooling
Fig. 1. View of the Neutral Beam Cell and the ITER vacuum vessel.
enabling the crane to be lowered while still mounted on a small section of the monorail, prior to being transferred through the NB cell door into a transport cask. 2.2. Beam Line Transporter The NBRHS Beam Line Transporter (BLT) consists of a powered swung rail and a fixed rail attached to the building, an articulating boom, telescopic mast and manipulator to provide dexterous handling of tools, Fig. 4. Its function is to allow maintenance of beam line components and front end components during replacement operations such as:
Fig. 2. Side view of a HNB (right) and duct to the vessel (left).
of the crane along the beam axes of the DNB and two HNB systems [3]. Various lifting adaptors are used to accommodate unique component geometries and specific transportation path requirements. Motorised twist locks are used as a standard interface fixture between the monorail crane, lifting adaptor and component. The monorail crane can be removed from the NB cell for maintenance or storage using the permanently installed transfer hoist, Table 1 Main NBRHS tasks. Maintenance task
Description
Caesium oven replacement Caesium oven cleaning Beam source Neutraliser Residual Ion Dump
RH class 1 Scheduled replacement RH class 2 Replacement upon failure Estimated failure probability: >0.3 in 20-year period
Calorimeter Fast shutter mechanism NB top lid NB rear flange Active control coils Exit scraper Passive magnetic shield Neutron shield Absolute valve Fast shutter NB cryopump High voltage bushing Upper port diagnostics Neutron flux monitor VV in-service inspection
• Cutting and re-welding of water cooling pipes and other services. • Cutting and re-welding lip-seals during opening/closing of the beam line vessel top lid and beam source vessel rear flange. • Bolting operations during opening and closing of lid and flange and replacement of components. The articulating boom and telescopic mast form one portable module that can be deployed at each of the swung rails of the respective beam line, thereby minimising duplication of equipment. In the current concept only one manipulator is present in the NB cell, which will be confirmed after the operation efficiency and rescue assessment in the next design phases. This manipulator can similarly be interchanged between various locations inside the NB cell, including the Beam Line Transporter and the beam source
RH class 3 Replacement upon failure Estimated failure probability >0.03 in 20-year period
Fig. 3. Monorail crane system, transporting a calorimeter with a generic lifting adaptor (exploded view).
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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Fig. 4. Beam Line Transporter accessing internal components whilst the top lid is lifted in its vertical position.
equipment, locating with a universal manipulator connector, transported by the monorail crane. The complementary services are provided by the service modules containing the local liquid and gas supplies, etc., which are also deployed with the monorail crane. Access to the Beam Line components is enabled by the sequential removal of the upper active correction and control coils, the upper segmented passive magnetic shield plates, and finally the Beam line vessel top lid. This requires unbolting of a rigid structural flange 3.5 m in length by 9.5 m in breath, then cutting (and subsequent re-welding on replacement) of a lip weld of the same nominal dimensions performing vacuum and confinement functions. Weighing 16 tonnes the top lid is lifted clear of the vessel using the top lid opening mechanism, a dedicated lifting device mounted on an adjacent pillar. Standard twist locks are used to connect the opening mechanism with the lid. 2.3. Beam source equipment Maintenance of the Caesium oven and Beam Source is performed by the NBRHS beam source equipment, Fig. 5, consisting of a support frame, a carriage, mast, articulated boom, manipulator, extension rails and a source carriage. The Beam Source is accessed via the Beam Source Vessel (BSV) rear flange after lowering the rear PMS plate, where tools for unbolting of the flange and cutting/rewelding of the lip seal are deployed. The Caesium ovens of the beam source are accessible through a small hinged door within the rear
PMS plate, in order to limit radiation levels during this scheduled maintenance. During opening, the rear flange is supported and repositioned by the BSV rear flange equipment. Similar in principle to the top lid opening mechanism, the BSV rear flange equipment is permanently installed in the NB cell. It engages with the rear flange on dowels and is locked in place by motorised bolts. Once open, all service connections and mounting fixtures are removed, and the Beam source is moved outside the vessel using the source carriage moving on the extension rails, where it can be collected by the monorail crane. 2.4. Manipulator A force reflecting, bi-lateral servo manipulator is foreseen for the NB cell, providing dexterous manipulation of tooling and discrete components. Using a common mating connector providing structural support, locking and all necessary service connections, the manipulator can be transported between locations, including the Beam Line Transporters, the beam source and upper port equipment. The concept design is based on a two arm manipulator with 50 kg lifting capacity and an additional 100 kg lifting capacity chest mounted winch, like the one presently operated at JET. 2.5. Tools A suite of generic and special tooling is foreseen for the over 70 individual components requiring remote maintenance within the NB cell, to support the various alignment, cutting, cleaning, welding and inspection tasks adapted to the different dimensions of the service connections.
Fig. 5. Beam source equipment maintaining the beam source (rear PMS plate underneath not shown here).
2.5.1. Pipe tooling Water cooling pipes for beam line components must be cut and re-welded during replacement operations. Designed for RH deployment with a manipulator, the Removable Bellows Assembly (RBA), Fig. 6, is a novel and flexible means to create a generous assembly clearance between beam line components being removed and the remaining plant components. Remote metrology of the cut pipe ends is made prior to installation of the RBA to determine any misalignment between pipe stubs. A bespoke replacement bellows section can then be prepared to ensure an optimal fit. Fine adjustment can also be made by manipulating the RBA pipe alignment
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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Fig. 8. Lip seal welding tool.
Flange bolting, lip cutting, welding and inspection tools are deployed on trolleys, guided by a rail running next to the flange and lip, Fig. 8.
Fig. 6. Removable bellows assembly.
tools to satisfy the fit-up tolerance necessary for orbital TIG welding. The pipe alignment tools also offer a common mounting slot for orbital cutting, welding and inspection tools, Fig. 7. 2.5.2. Flange tooling The NB system top lid, rear flange and front end components feature a lip seal that is cut and subsequently re-welded during RH interventions. The lip seal is a partial penetration weld suitable as a vacuum and confinement barrier, while structural loading is borne by a rigid bolted flange, isolating the lip from stresses.
2.5.3. Bolt tooling A set of standard RH bolting tools based on IO’s RH standards and bespoke tools have been outlined. • Torque multiplying bolt runners, originally developed at JET, driven by the manipulator gripper giving the operator tactile sensing feedback during bolting, for a M12–M36 bolt sizes. • Powered torque tools, for M12–M36 of bolt sizes. • Lay shaft and lay shaft tools, i.e. long reach tool for difficult to access bolts, such as those fixing the beam line vessel components to their supporting beds. RH standard captive bolts are used, holding the bolt in place on the component after thread disengagement. 3. Neutral Beam Remote Handling system R&D activities During the Neutral Beam Remote Handling concept design phase a number of research and development needs were identified. These include on board control and communications for the monorail crane and remote cutting, re-welding and inspection of pipes and lip seals. F4E is proceeding with these tasks to further establish the technical feasibility of the Remote Handling system prior to continuing design and production of the complete NBRHS with the industrial suppliers during the next to come procurement phase. 3.1. Monorail crane on-board control system development
Fig. 7. Deployment of pipe tooling.
For RH equipment operating on activated structures, radiation sensitive electronics such as motion controllers and other integrated electronics are strictly located away from the work area in shielded locations. Every effort is made to ensure only the bare minimum of vulnerable components are placed in the field such as actuators and diagnostics serviced by umbilical. In the case of the monorail crane, due to the length and circuitous routing of the rail a classical umbilical is not technically feasible. Alternative solutions have been considered such as CAN bus communications using dedicated additional bars in the monorail conductor rail, however this system suffers from susceptibility
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043
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to noise and low bandwidth, preventing transmission of camera data for example. Discrete plug-in points again using a dedicated communications rail on the monorail conductor bar could allow the crane to move up to a few metres in either direction whilst plugged in, however a dedicated plug-in mechanism and numerous plug in points at short intervals would be required. The preferred solution uses wireless transmission in parallel with CAN bus communications to communicate operator commands to a control system located on-board the monorail crane. Such a system would necessitate potentially sensitive electronics such as a wireless transceiver, real-time motion control processor along with actuator drivers, all working in a ␥ environment. A R&D activity is being carried out by F4E’s engineering support supplier Oxford Technologies Ltd. to identify commercial off the shelf (COTS) components for the monorail crane on-board control unit capable of tolerating the radiological conditions inside the NB cell during shut down. The crane design features an estimated 40 actuators including: locomotion motors, lifting drum motors, brakes and twist lock actuators, all to be serviced by the on-board control unit. In addition an estimated 81 sensors such as resolvers, multiple limit switches, a load cell and a camera will also interface with the controller. Other necessary on-board functionality includes: remotely resettable circuit breakers, fire detection, on-board radiation monitoring, temperature control and emergency stop. Components operating in the NB cell during shutdown only are required to have a minimum radiation life time of 20 kGy equating to 119 weeks full time operation at the maximum expected dose rate of 1 Gy/h. A total of 243 on-board electrical components were identified during the study, occupying a volume of 225 l, requiring a total of 600 wires. Given the available volumes for control elements, a realistic thickness of lead shielding yields a minimum radiation hardness target of only 1 kGy, though this remains to be verified against the resulting extra loading during seismic events. COTS components for all necessary processors such as: motion controllers, resolvers, I/O processing and load cell were successfully found rated at 1 kGy, most of them being developed previously for space applications. No suitable actuator drivers could be identified, requiring adaptation with radiation hard subcomponents and possibly radiation testing. Similarly power supplies, accelerometer, cooling and fire detection units could not be identified with adequate radiation tolerance. 3.2. Pipe and lip seal maintenance
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conditions. UHV class welding and cutting are highly skilled tasks and demand the precise control of parameters such as metallurgic composition, component geometry, joint fit-up and tool placement to give some examples. Remote Handling deployment of tools implies limited dexterity, limited vision and reduced manoeuvrability compared to a skilled human operator. Special considerations in the design of RH cutting/welding tooling must therefore be made together with rigorous mock-up testing in order to ensure the consistent creation of the optimum joint. The implications of a failure in either the tooling or the finished joint are serious; this together with the first of a kind deployment of such tooling has stimulated an R&D activity due to commence in the latter half of 2013. Prototype proof-of-principle lip and orbital pipe cutting and welding tools along with support tools such as alignment will be developed and tested in parametric conditions. Results will be used as input for the industrial supply of the NBRHS. 4. Conclusion The conceptual design of the NBRHS has been successfully defined. As part of this process, specific technology needs have been identified, such as radiation tolerant components for the monorail crane on-board control system and remote cutting and welding of pipes and lip seals. R&D activities are underway on both topics with the aim of reducing both technological and managerial risks in the final industrial supply. Disclaimer The views expressed in this publication are the sole responsibility of the authors and do not necessarily reflect those of the ITER Organization or Fusion for Energy. Neither Fusion for Energy nor any person acting on behalf of Fusion for Energy is responsible for the use which might be made of the information in this publication. References [1] C.-H. Choi, J. Palmer, C. Conesa, J.-P. Friconneau, J.-P. Martins, R. Subramanian, et al., Remote Handling concept for the neutral beam system, Fusion Engineering and Design 86 (2011) 2025–2028. [2] N. Sykes, C. Belcher, C.-H. Choi, O. Crofts, R. Crowe, C. Damiani, et al., Status of ITER neutral beam cell remote handling system, Fusion Engineering and Design 88 (9–10) (2013) 2043–2047. [3] O. Crofts, P. Allan, J. Raimbach, A. Tesini, C.-H. Choi, C. Damiani, et al., Applying remote handling attributes to the ITER neutral beam cell monorail crane, Fusion Engineering and Design 88 (9–10) (2013) 2057–2061.
ITER will be the first nuclear installation where welding and cutting of pipes and lip seals are performed routinely under RH
Please cite this article in press as: R. Shuff, et al., Progress in the design of the ITER Neutral Beam cell Remote Handling System, Fusion Eng. Des. (2014), http://dx.doi.org/10.1016/j.fusengdes.2014.01.043