1. T2K Remote Handling T. Sekiguchi (KEK) on behalf of Tada (KEK) 2012/11/10

2. Target Horns Beam Helium vessel Upper Concrete Shields Decay Volume Beam window Monitor stack Equipments that need maintenance by remote handling in Target Station (TS) Buffle Upper Iron Shields

3. 3rd Horns Beam Helium vessel Decay Volume Equipments that need maintenance by remote handling in Target Station (TS)

4. 3rd Horns Beam Helium vessel Decay Volume Equipments that need maintenance by remote handling in Target Station (TS) Motivation : Inspection for horns after earthquake (If necessary, exchange for new horn)

5. Areas in TS Assemble and adjust the new horn at the horn dock area Take the old horn from the beam line area to the maintenance area Exchange from the old horn to the new horn at the maintenance are Install the new horn to the beam line area Put the old horn into the casket at the storage area Maintenance area Crane control room Horn dock area Storage area Beam line area (Service-pit)

6. Trip of the 3rd horn Maintenance area Crane control room Horn dock area Storage area Beam line area (Service-pit) 3rd horn was taken out from the helium vessel, put on the maintenance area, and set into the helium vessel again.

7. Remote Maintenance for Horns Concrete Shield 1m Iron Shield 2.3m Support Module for Horn HornHorns and shields are handled by the remote controlled handling machines when they are taken out of the beam line, because of the high radioactivation of them. Concrete shield Horns are shielded by iron and concrete shields and the workers can access only above the these shields.

8. Remote maintenance devices for horn maintenance 2) Horn handling machine to move the horn: beam line ⇔ maintenance area Horn support module Horn 3) Casket to store the used horn 4) Lift table to connect/disconnect the horn from the support module Horn 1) Numerical controlled crane to carry the remote maintenance devices

9. Concept of the remote handling for horns A numerical controlled overhead crane Position accuracy = a few cm Remote handling machines for horns Position accuracy = a few mm Crane Handling machine for horns This crane has a spare system. If the crane stops during moving, the main system is cut off, and the spare one runs and keeps on the work. Guide cell Horn support module

10. Horn handling machine lock unlock Horn Support module Handling machine takes hold of the top of the support module Guide roller Twist-lock pin To engage the roller with the guide cell, the positional precision of a few mm is achieved.

11. This crane is controlled from the control room and all electronics for control are set there because it works under very high radiation environment. Display for the camera Control stick (for the manual operation mode) Control panel

12. Remove the busbars and pipes (by manual) Busbars Water cooling pipes Helium vessel Set the guide cell on the helium vessel (by manual) Guide cell Concrete shield above the 3rd horn Horn support module (Handling point : twist lock hole) Take out the 3rd horn

13. Remove the concrete shield above the horn (by remote) Handling machine for shields Concrete shield above the 3rd horn After removal of the concrete shield Iron shields above the 3rd horn Horn support module

14. Remove the iron shields above the horn (by remote) Handling machine for shields Iron shield above the 3rd horn Detect the radiation level of the iron shield (by manual) Iron chamber with long arm 10 mSv/hour

15. Change the handling machine into the horn handling machine (by manual) After removal of the all shields above the 3rd horn Handling machine for horns

16. Approach the 3rd horn (by remote) Take hold of the 3rd horn (by remote) Handling machine for horns Horn support module Guide cell

17. Pull out the 3rd horn from the helium vessel along the guide cell (by remote) Rotate the 3rd horn at 90 degree (by remote) 12mSv/h 7mSv/h

18. Take the 3rd horn into the maintenance area (by remote) Put the 3rd horn on the support base in the maintenance area (by remote) Support base in the maintenance area Horn support module Guide cell in the maintenance area

19. 3rd horn in the maintenance area Helium vessel After removal of the 3rd horn Hole of the hell

20. Put the concrete shields above the 3rd horn in the maintenance area and the helium vessel to work there (by remote) Then we can work above the horn and the helium vessel!

21. 1m 7m 30mm Handling machine Guide cell Other equipment Horn Support module 3rd horn and its support module tilted within the clearance between the guide cell and the guide roller of the handling machine. Because the guide length of the handling machine is 1m, the clearance between the horn and the other equipment was expended. We watched trough cameras only upper level. (Not watched underground level) Guide clearance 5mm Water Support Bracket Broken When Returned to Vessel Tilted by 20~30mm

22. Hit points Support brachet for the water pipe Support parts for the DV collimater Two of the support brachets has come off South-side one on the bottom of the vessel North-side one stuck on the other support part

23. We picked up the north-side block (stuck one). (South-side one remains on the bottom of the vessel). We inspected the pipes visually. It looks there are no damages. The airtight test was done. Pressure : atmospheric pressure + 0.1MPa Pressure drop was not observed in 30min. Water circulation test was done. No water leaks have been observed.

24. Countermeasure for the Tilt Problem: Counter Weight Counter weight We made the counter weights for the current and other spear horns. Other countermeasures: Attach remote-displayed tilt sensor Watch all the gaps by remote cameras.

25. In-situ Inspection of Other Horns From the visual inspection of 3 rd horn, no significant damage found. For other horns, in-situ inspection was done. –Relative alignment of horn and support module was checked.

26. Alignment Frame Four remote cameras A laser alignment tool Lights Lear actuators to move the cameras and laser alignment tool. Remote cameras Laser alignment tool Remote cameras

27. Lowering down to vesselSet to vessel Setting of Alignment Frame Moving to vessel Laser line is adjusted by looking at pictures of remote cameras

28. How to check relative alignment Lower two strings at upstream and downstream of support module based on the center of support module. Adjust the laser line to match two strings. Then compare the laser line and center line of horns Laser lines Strings Upstream string Downstream string

29. Horn Alignment Result Relative position was correct within alignment precision (~1mm). –No significant deformation due to earthquake was observed. Laser line (module center) Scribe line (horn center) Horn1 upper Horn1 center Horn2 upperHorn2 lower Horn3 upperHorn3 lower Laser line width ~0.7mm Laser line width ~0.8mm Laser line width ~1.4mm

30. Summary Remote maintenance of irradiated 3 rd horn was performed. –This system worked well basically, but there are some problems to be fixed. –Countermeasures will be made by next remote maintenance. Visual inspection of horns were made. –No significant damage found and alignment was still OK after big earthquake.

31. BACKUP

32. Radiation survey of the horns and the helium vessel before the handling for horns Total POT ~ 1.46×10 20 protons Beam stopped on March 11 Measured around the buffle, the 1st horn and the 2nd horn on June 22 (103 days cooling) Measured around 3rd horn on July 21 (132 days cooling) These results include both effects from the horns and the helium vessel.

33. Horizontal survey at TP+0.005 level (150mm height from the iron shield bottom) 14.7 mSv/h 13.7 mSv/h 30 mSv/h 23 mSv/h 6 mSv/h 5 mSv/h 7.8 mSv/h June 22 July 21

34. Vertical survey at inside surface of the upstream-plate of the helium vessel 430mm June 22

35. Vertical survey at rear side surface of the upstream-plate of the 1st module 1010mm June 22

36. 900mm Vertical survey at front side surface of the upstream-plate of the 2nd module July 21

37. 300mm Vertical survey at front side surface of the upstream-plate of the 3nd module July 21

38. Radiation survey of the horns and the helium vessel independently Total POT ~ 1.46×10 20 protons Beam stopped on March 11 Measured 3rd horn and helium vessel independently on August 22 (164 days cooling)

39. Vertical survey at front side surface of the 3rd horn August 22

40. Vertical survey at rear side surface of the 3rd horn August 22

41. MARS simulation→ multiply POT rate simplyMeasurement Power x time750kW x 100days POT1.35x10 21 1.46x10 20 Cooling time180 days 164 days 1st horn6800 mSv / h740 mSv / h 2nd horn 1500 mSv / h160 mSv / h 3rd horn 380 mSv / h 41 mSv / h7 mSv / h Comparison with MARS simulation (by Oyama-san) Measured value of the radioactivation is ~1/6 compared with MARS simulation. Good news for the remote maintenance scenario based on this simulation Casket 45 μSv/h 3 μSv/h 6800 mSv/h Example of the casket design for the 1st horn Disposed 1st horn

42. Vertical survey at upstream of the 3rd horn position August 22

43. Vertical survey at downstream of the 3rd horn position August 22

44. Trip of the 3rd horn Maintenance area Crane control room Horn dock area Storage area Beam line area (Service-pit) The highest radiation level was observed outside of the targetstation building when the horn moved to maintenance area Problem: Too High Radiation Level outside Building

45. 7 mSv/h 65 μSv/h 660 μSv/h Wall thickness 200 mm Wall of the building (Boundary of the radiational management area) Outside of the building (General area) Ground level 12 mSv/h We need to reduce the radiation level by 1 or 2 orders. 3m Cross section of the targetstation near the maintenance area Inside of the building (Management area)