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Assembly of ITER blanket module to vacuum vessel experimental investigations
Fusion Engineering and Design 58 – 59 (2001) 567– 571 www.elsevier.com/locate/fusengdes
Assembly of ITER blanket module to vacuum vessel experimental investigations L.P. Jones a,*, Ph. Alfile´ b, C. Antonucci c, A. Cardella d, C Dupuy b, W. Daenner a, F. Elio d, D. Maisonnier a, A. Pizzuto c, T. Schmeskal e a
EFDA CSU, Garching 85748, Germany b CEA, Arceuil 94114, France c ENEA, Brasimone 40032, Italy d ITER JCT, Garching 85748, Germany e O8 AW Seibersdorf 2444, Austria
Abstract The ITER modules are connected to the vacuum vessel wall mechanically, electrically and hydraulically in a way suitable for remote handling with access from the frontside only. In order to validate the design and operation of the attachment systems for the 1998 ITER design, EFDA directed three Associations (ENEA, Brasimone, (O8 AW Seibersdorf and CEA, Arceuil) in tasks including process investigations and the design, procurement and testing of three ITER-representative mock-ups. ENEA, Brasimone procured and provides the site for the largest rig, the Blanket Module Carrier, which provides 6-axis movements of a 4 ton module mock-up to simulate the mounting of a typical ITER module to a vertical wall. O8 AW Seibersdorf designed an ITER remote-handling-compatible, water-hydraulically-operated bolting tool, which ENEA, Brasimone procured and used in a test programme. CEA, Arceuil developed and tested a special bore tool using a NdYAG laser for cutting and welding the hydraulic connectors. The overall programme demonstrated the concept viability and highlighted problem areas of the assembly procedure of the blanket module-to-wall attachment. Aspects of the work still require further attention to refine and finally validate the techniques especially with regard to the ITER-FEAT design. © 2001 Elsevier Science B.V. All rights reserved. Keywords: ITER; Blanket module; Vacuum vessel
1. Blanket module assembly tests The ITER module attachment scheme [1,2], reproduced in these mock-up experiments, relates to the design in which in-plane magnetic forces * Corresponding author. Tel.: +49-89-3299-4278; fax: + 49-89-3299-4198. E-mail address: [email protected] (L.P. Jones).
are reacted by a single offset locating cylinder. The interlocking side-mounted keys, that are located on alternate (male) modules and restrains the module-rotation torque, are reproduced on the vessel wall in the full-scale mock-up shown in Figs. 1 and 2. The linear motions at 60 mm/s for each to a stroke 50 mm stroke (500 mm normal to wall)
0920-3796/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 0 - 3 7 9 6 ( 0 1 ) 0 0 4 9 7 - 5
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L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 1. Sketch of blanket module carrier.
provide movements with backlash less than 0.05 mm while the rotation movements to 2.5° need resolved motions of the electrical-motor/screw rams. A laser tool uses an accurate rectilinear block to measure module to vessel orientation to 0.01 mm. An inboard female module, 1.6 m wide, 1.0 m high and 0.4 m thick, weight 3.7 tons has been simplified and made from carbon steel instead of 316LN but with docking features faithfully reproduced. Four dummy flexible cartridges, each with a captive M45 bolt and washer, were screwed into the rear side of the module, as with the real supports. Two branch pipes and earth straps are aligned and bolted to the vessel with a flange. Eight, 30 mm cylindrical holes through the module allow access to the flexible attachment M45 bolts, the earth strap M20 bolts and the branch pipes for welding. The mock-up vessel, made from carbon steel, has a fixed centre pin and detachable keys. Compensation cups for abutment of the four flexible cartridges allow the adjustment of their radial position, which are necessary to bring the cartridges in simultaneous contact to the vessel (detected by electrical contacts). A 3D-metrology survey examined the features with the shaded planes shown in Fig. 3a and b and the CAD simulation used this data to assess clearances and establish optimum relative orientations. Considerable confidence was built by this procedure when compared to experimental results. Successful operations were demonstrated with the ITER-specified clearances of the centrepin (¥ 200 mm) from 0.24 to 0.44 mm and the keyways from 0.1 to 0.25 mm. First-time assembly success was achieved by off-line clearance adjustment by survey. To ensure contact on all four ‘flexible-connector’ ends a measured force of 600 N was required.
2. NdYAG welding and cutting tool
Fig. 2. Photo of blanket module carrier.
A 450 mm, prototype tool (shown in Fig. 4 and Fig. 5) with right angle focusing head was designed and procured to cut and weld module hydraulic connections of 316L SS, internal diame-
L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 3. (a) Surveyed features of vessel. (b) Surveyed features of module.
Fig. 4. Sketch of laser tool.
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ter 55 mm, 3 mm thick, through a front access hole of 30 mm diameter. A pulsed 1.2 kW (peak power 30 kW) YAG laser is directed successively via a 20 m long, 1 mm diameter fibre, two silica lenses, and a water cooled, gold plated, copper folding mirror. The cutting/welding operations are carried out from inside the tube with a coaxial nozzle, that protects against some fume and spatter damages. For cutting, an off-axial nozzle was used to improve the removal of the molten metal. For welding a coaxial nozzle of 5 mm output diameter is used to protect the molten pool from oxidation. Conventionally, gas-assisted steel cutting with a YAG is performed with a single stroke by focusing the beam on the surface of the workpiece while removing the molten metal out of the kerf with a jet of gas close to the cut. Best results for single cuts were an average power of 800 W, 80 J/pulse at 80 mm/min with a roughness of 5 mm and a parallel kerf profile. The drawback of single pass cutting is the dispersion of the dross outside the nozzle, which affects the clean conditions of the vessel. Therefore, a two pass cut was considered to confine the majority of the dross achieved during the first layer pass inside the nozzle. The first stroke reached (the deepest incomplete cut possible) 2.5–2.8 mm and the second stroke severed the metal, as shown in the ring of Fig. 6. The mean power was 100 W and the process speed 80 mm/min. Unlike the monopass cutting, this method does not allow rewelding with a new nozzle and the edge has to be re-machined. Welding to clean metal at 700 W, with Helium gas assist, at a speed of 190 mm/min produced a weld with light undercut due to the use of a pulsed laser and a full penetration with neither porosity nor cracks as shown in the centre of Fig. 6. In order to avoid defects on the weld bead while stopping abruptly the laser beam, the laser power was faded down to 300 W on 10 mm after a complete turn. Both cutting methods and welding were unaffected by the tube flattening or an offcentre orbital head, resulting in a de-focussing of up to 1 mm. The results of this development have shown success in carrying out the basic process. However, the roughness and V shaped cut of about 2°
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L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 5. Photo of laser tool.
precludes reweld without machining so it is not suitable for ITER-RH applications. A new task is therefore in progress to design a new co-axial connector and tool design with a larger diameter (75 mm) outer pipe, recently devised for ITERFEAT, utilising instead the new availability of continuous wave 4 kW laser. A retractable nozzle will be used for close in blowing of cutting dross and also to protect the mirror from damage. Efforts will also be made to reduce the dark fumes produced during laser welding that condense onto the tube and, unless protected, the optics.
The lance torque capability via a water hydraulic motor/gearbox is limited by the 30 mm access hole size to 300 Nm, which is provided for only in the event of any possible unbolting (sticking) problems in service. The tool was mounted on an experimental rig to measure applied torque, temperature and load/stress applied to the bolt collar (as the bolt experiences too high temperatures for normal strain gauges). The required 750 N/mm2 preload was readily achieved by heating the bolt to 350 °C taking about 6 min with the collar temperature remaining under 650 °C. The unbolting process was similarly trouble-free, with
3. Bolting tool The normal-to-wall mechanical forces are resisted by four ‘flexible’ cartridges, which are attached to the module and bolted to the structure during the connection sequence. The high preload of the M45 bolts required can only be achieved by thermal expansion before tightening because the 30 mm access hole through the module is not large enough for a stronger tool. A separately driven, 12 mm diameter, 1320 W heater is inserted down the centre of the bolt. The tool shown in Fig. 7 and Fig. 8 includes a pneumatically actuated axial movement of 350 mm so that it may carry out operations from a fixed position.
Fig. 6. Cut pipe and weld cross-section.
L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
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Fig. 7. Principle of bolting tool.
Fig. 8. Photo of bolting tool rig.
the collar temperature rising to only 850 °C (after the heater was turned off) and no visible difference between heating rates for bolting and unbolting. There is a new task in progress to validate the system for the new reversed bolt design adopted by ITER-FEAT.
References [1] F. Elio et al., Progress in the ITER blanket design, l7th SOFT conference, San Diego, 1997. [2] F. Elio et al., Engineering design of the ITER blanket and relevant research and development results, 20th SOFT conference, Marseilles, 1998.
Assembly of ITER blanket module to vacuum vessel experimental investigations L.P. Jones a,*, Ph. Alfile´ b, C. Antonucci c, A. Cardella d, C Dupuy b, W. Daenner a, F. Elio d, D. Maisonnier a, A. Pizzuto c, T. Schmeskal e a
EFDA CSU, Garching 85748, Germany b CEA, Arceuil 94114, France c ENEA, Brasimone 40032, Italy d ITER JCT, Garching 85748, Germany e O8 AW Seibersdorf 2444, Austria
Abstract The ITER modules are connected to the vacuum vessel wall mechanically, electrically and hydraulically in a way suitable for remote handling with access from the frontside only. In order to validate the design and operation of the attachment systems for the 1998 ITER design, EFDA directed three Associations (ENEA, Brasimone, (O8 AW Seibersdorf and CEA, Arceuil) in tasks including process investigations and the design, procurement and testing of three ITER-representative mock-ups. ENEA, Brasimone procured and provides the site for the largest rig, the Blanket Module Carrier, which provides 6-axis movements of a 4 ton module mock-up to simulate the mounting of a typical ITER module to a vertical wall. O8 AW Seibersdorf designed an ITER remote-handling-compatible, water-hydraulically-operated bolting tool, which ENEA, Brasimone procured and used in a test programme. CEA, Arceuil developed and tested a special bore tool using a NdYAG laser for cutting and welding the hydraulic connectors. The overall programme demonstrated the concept viability and highlighted problem areas of the assembly procedure of the blanket module-to-wall attachment. Aspects of the work still require further attention to refine and finally validate the techniques especially with regard to the ITER-FEAT design. © 2001 Elsevier Science B.V. All rights reserved. Keywords: ITER; Blanket module; Vacuum vessel
1. Blanket module assembly tests The ITER module attachment scheme [1,2], reproduced in these mock-up experiments, relates to the design in which in-plane magnetic forces * Corresponding author. Tel.: +49-89-3299-4278; fax: + 49-89-3299-4198. E-mail address: [email protected] (L.P. Jones).
are reacted by a single offset locating cylinder. The interlocking side-mounted keys, that are located on alternate (male) modules and restrains the module-rotation torque, are reproduced on the vessel wall in the full-scale mock-up shown in Figs. 1 and 2. The linear motions at 60 mm/s for each to a stroke 50 mm stroke (500 mm normal to wall)
0920-3796/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 0 - 3 7 9 6 ( 0 1 ) 0 0 4 9 7 - 5
568
L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 1. Sketch of blanket module carrier.
provide movements with backlash less than 0.05 mm while the rotation movements to 2.5° need resolved motions of the electrical-motor/screw rams. A laser tool uses an accurate rectilinear block to measure module to vessel orientation to 0.01 mm. An inboard female module, 1.6 m wide, 1.0 m high and 0.4 m thick, weight 3.7 tons has been simplified and made from carbon steel instead of 316LN but with docking features faithfully reproduced. Four dummy flexible cartridges, each with a captive M45 bolt and washer, were screwed into the rear side of the module, as with the real supports. Two branch pipes and earth straps are aligned and bolted to the vessel with a flange. Eight, 30 mm cylindrical holes through the module allow access to the flexible attachment M45 bolts, the earth strap M20 bolts and the branch pipes for welding. The mock-up vessel, made from carbon steel, has a fixed centre pin and detachable keys. Compensation cups for abutment of the four flexible cartridges allow the adjustment of their radial position, which are necessary to bring the cartridges in simultaneous contact to the vessel (detected by electrical contacts). A 3D-metrology survey examined the features with the shaded planes shown in Fig. 3a and b and the CAD simulation used this data to assess clearances and establish optimum relative orientations. Considerable confidence was built by this procedure when compared to experimental results. Successful operations were demonstrated with the ITER-specified clearances of the centrepin (¥ 200 mm) from 0.24 to 0.44 mm and the keyways from 0.1 to 0.25 mm. First-time assembly success was achieved by off-line clearance adjustment by survey. To ensure contact on all four ‘flexible-connector’ ends a measured force of 600 N was required.
2. NdYAG welding and cutting tool
Fig. 2. Photo of blanket module carrier.
A 450 mm, prototype tool (shown in Fig. 4 and Fig. 5) with right angle focusing head was designed and procured to cut and weld module hydraulic connections of 316L SS, internal diame-
L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 3. (a) Surveyed features of vessel. (b) Surveyed features of module.
Fig. 4. Sketch of laser tool.
569
ter 55 mm, 3 mm thick, through a front access hole of 30 mm diameter. A pulsed 1.2 kW (peak power 30 kW) YAG laser is directed successively via a 20 m long, 1 mm diameter fibre, two silica lenses, and a water cooled, gold plated, copper folding mirror. The cutting/welding operations are carried out from inside the tube with a coaxial nozzle, that protects against some fume and spatter damages. For cutting, an off-axial nozzle was used to improve the removal of the molten metal. For welding a coaxial nozzle of 5 mm output diameter is used to protect the molten pool from oxidation. Conventionally, gas-assisted steel cutting with a YAG is performed with a single stroke by focusing the beam on the surface of the workpiece while removing the molten metal out of the kerf with a jet of gas close to the cut. Best results for single cuts were an average power of 800 W, 80 J/pulse at 80 mm/min with a roughness of 5 mm and a parallel kerf profile. The drawback of single pass cutting is the dispersion of the dross outside the nozzle, which affects the clean conditions of the vessel. Therefore, a two pass cut was considered to confine the majority of the dross achieved during the first layer pass inside the nozzle. The first stroke reached (the deepest incomplete cut possible) 2.5–2.8 mm and the second stroke severed the metal, as shown in the ring of Fig. 6. The mean power was 100 W and the process speed 80 mm/min. Unlike the monopass cutting, this method does not allow rewelding with a new nozzle and the edge has to be re-machined. Welding to clean metal at 700 W, with Helium gas assist, at a speed of 190 mm/min produced a weld with light undercut due to the use of a pulsed laser and a full penetration with neither porosity nor cracks as shown in the centre of Fig. 6. In order to avoid defects on the weld bead while stopping abruptly the laser beam, the laser power was faded down to 300 W on 10 mm after a complete turn. Both cutting methods and welding were unaffected by the tube flattening or an offcentre orbital head, resulting in a de-focussing of up to 1 mm. The results of this development have shown success in carrying out the basic process. However, the roughness and V shaped cut of about 2°
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L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
Fig. 5. Photo of laser tool.
precludes reweld without machining so it is not suitable for ITER-RH applications. A new task is therefore in progress to design a new co-axial connector and tool design with a larger diameter (75 mm) outer pipe, recently devised for ITERFEAT, utilising instead the new availability of continuous wave 4 kW laser. A retractable nozzle will be used for close in blowing of cutting dross and also to protect the mirror from damage. Efforts will also be made to reduce the dark fumes produced during laser welding that condense onto the tube and, unless protected, the optics.
The lance torque capability via a water hydraulic motor/gearbox is limited by the 30 mm access hole size to 300 Nm, which is provided for only in the event of any possible unbolting (sticking) problems in service. The tool was mounted on an experimental rig to measure applied torque, temperature and load/stress applied to the bolt collar (as the bolt experiences too high temperatures for normal strain gauges). The required 750 N/mm2 preload was readily achieved by heating the bolt to 350 °C taking about 6 min with the collar temperature remaining under 650 °C. The unbolting process was similarly trouble-free, with
3. Bolting tool The normal-to-wall mechanical forces are resisted by four ‘flexible’ cartridges, which are attached to the module and bolted to the structure during the connection sequence. The high preload of the M45 bolts required can only be achieved by thermal expansion before tightening because the 30 mm access hole through the module is not large enough for a stronger tool. A separately driven, 12 mm diameter, 1320 W heater is inserted down the centre of the bolt. The tool shown in Fig. 7 and Fig. 8 includes a pneumatically actuated axial movement of 350 mm so that it may carry out operations from a fixed position.
Fig. 6. Cut pipe and weld cross-section.
L.P. Jones et al. / Fusion Engineering and Design 58–59 (2001) 567–571
571
Fig. 7. Principle of bolting tool.
Fig. 8. Photo of bolting tool rig.
the collar temperature rising to only 850 °C (after the heater was turned off) and no visible difference between heating rates for bolting and unbolting. There is a new task in progress to validate the system for the new reversed bolt design adopted by ITER-FEAT.
References [1] F. Elio et al., Progress in the ITER blanket design, l7th SOFT conference, San Diego, 1997. [2] F. Elio et al., Engineering design of the ITER blanket and relevant research and development results, 20th SOFT conference, Marseilles, 1998.