FP7-Fission LUCOEX Large Underground Concept EXperiments Project Progress Meeting 14th May 2014 WP5 Quality Control of Buffer Installation in KBS-3V Keijo Haapala

QUALITY TARGETS IN LOT2 Q1: The integrity of the buffer blocks during the process. Q2: The quality of the position of the assembled buffer and the bentonite blocks the buffer consists of. Q3: The width of the gap between assembled block and the host rock. Q4: The compactness of the join between the pellets and the host rock. 14th May 20142Haapala Keijo

Q1: The integrity of the buffer blocks during the process. Inspection of block before lowering it to the disposal hole. Fractures? Colour? Something abnormal? The block is in the container during transportation 14th May 20143Haapala Keijo

4 Q1: The integrity of the buffer blocks during the process. Inspection task and the suggested approach: To reduce the complexity the sensor assembly should be mounted to the transportation vehicle 14th May 2014Haapala Keijo

5 Q1: The integrity of the buffer blocks during the process. Studied technologies:  Short distance laser scanner (LS)  White light technology (WLT)  Machine vision (MV)  Acceleration and pressure data logger as support sensor -> AN ELECTRIC JUNGLE! LSWLTMV Accuracy µm Shots, rounds x (per one round) 11 x 55 = 6052 x 11 = 225 x 28 = 140 Engineering effort Electronics+ sensor cost k€ Feasibility % th May 2014Haapala Keijo

Q1: The integrity of the buffer blocks during the process. According the results from estimations, video inspection is sufficien inspection. -> The block will be inspected by cameras when it has been lifted out from transportation container, before lowering to the deposition hole. 14th May 20146Haapala Keijo

7 Q2: The Positioning Quality of Buffer Blocks  Motivation is to guarantee that 1.the copper canister fits into the constructed bentonite buffer. 2.the gap between host rock and buffer blocks allows proper pellet filling  Nominal clearance between the buffer blocks and the canister is 10 mm and 25-75mm between the host rock and buffer blocks  To reach the target we have to observe/check: 1.That the XY-position of each block and the whole buffer is within ±1mm from the target 2.The angle to which blocks settle 3.That the surface to which the block will be lowered is free from particles 14th May 2014Haapala Keijo

8 Q2: The Positioning Quality of Buffer Blocks Task 1: Check that the XY-position of each block and the whole buffer is within ±1mm from the target.  The target XY-position is calculated based on hole’s QA data and given to the buffer installation machine (BIM) as point in tunnel coordinate system -> XY-position of an installed block is very hard verify with reasonable accuracy with any other instrument than the laser tracker which guides the block to correct position while lowering process.  Machine vision or laser scanners are able to observe how blocks are aligned in respect of each other but they can’t tell accurately how well the whole buffer structure is positioned in respect the target coordinates.  -> The best guarantee to achieve the required accuracy is to monitor the accuracy of the laser tracker (LT). 14th May 2014Haapala Keijo

9 Q2: The Positioning Quality of Buffer Blocks Task 1: Check that the XY-position of each block and the whole buffer is within ±1mm from the target.  LT’s accuracy can be monitored with measuring the coordinates of know reference points every now and then  Disadvantage of using the LT is that the measurement is indirect (LT tracks the container which holds the bentonite block) -> Monitoring block’s movements during the transportation and its actual position in the container just before lowering the block to the hole would increase the reliability.  The gap (QA3) width monitoring can be used as a support measurement. By comparing the measured and expected gap width at the installation depth the XY-position of a block can be derived with accuracy of 5-10mm 14th May 2014Haapala Keijo

10 Q2: The Positioning Quality of Buffer Blocks Task 2: Observe the angle to which blocks settle  Accuracy target for the measurement is 0.01 degrees  Studied approaches : Gripper/container mounted high grade inclinometer (INC), Laser tracker (LT) and a laser distance meter with rotating fixture (LDM) LTINCLDM Accuracy, degrees0.01 Direct measurementNo Yes Required time, sec10,520 Engineering effort Sensor + electronics HW Cost, k€ 0 (included already) 8-13 (if mounted on the gripper) 4-10 Feasibility % th May 2014Haapala Keijo

11 Q2: The Positioning Quality of Buffer Blocks Task 2: Observe the angle to which blocks settle  High end inclinometer doesn’t provide any advantages compared to laser tracker even if mounted to the container instead of gripper. Container mounting multiplies the cost by the amount of containers.  Laser tracker measures block’s angle indirectly via container but that shouldn’t be a problem while there is no credible mechanism moving the block in z direction in a container.  Laser distance meter mounted in rotating fixture at BIM’s frame would provide direct measurement with the same accuracy as the laser tracker. The rotating fixture will probably be needed in other QA actions ( touch point clean – detection, gap width measurement and pellet formation capture.  Recommended approach is to use the laser tracker and optionally the laser distance meter to add reliability and to provide direct measurement. 14th May 2014Haapala Keijo

12 Q2: The Positioning Quality of Buffer Blocks Task 3: Check that the surface to which the block will be lowered is free from particles  Checking has to be done preferably from the level of BIM’s frame.  Target resolution is the size of one bentonite pellet (5x10mm, d x l) which is the most probable candidate for a foreign particle.  Laser scanner (LS) and machine vision (MV)  With laser scanning it takes 5-8 minutes to get the results which is too much. -> Machine vision is the only feasible technic  Machine vision’s accuracy is high enough and can be boosted with structured laser illumination.  Sensor HW cost for the MV is 10-23k€ depending on camera’s resolution. Same unit can be used in gap width and pellet filling measurements 14th May 2014Haapala Keijo

Q2: The Positioning Quality of Buffer Blocks -> To avoid continue more deeply in the Electric Jungle: Laser tracker and inclinometer are suitable for precise installation. According the estimations, camera inspection is sufficien to check that installation area is free from particles. 14th May Haapala Keijo

14 Q3: The width of the gap between assembled block and the host rock.  The gap filling is planned in prior the actual buffer installation based on the 3D model of the hole.  By measuring the gap between the host rock and just assembled block we can verify that the process goes as planned  Because of drilling, the surface of the host rock is not smooth while it might have horizontal roughness of 10mm.  The accuracy target for the gap width measurement is 5mm. 14th May 2014Haapala Keijo

15 Q3: The width of the gap between assembled block and the host rock.  Measuring can be done either from the gripper right after the block is released or from the level of BIM’s frame after the gripper has been lifted from the hole.  Cons of the gripper approach are: o Only three observation points which combined to rough surface may result in false results o Block’s outer edge is not visible because the diameter of the container has to be bigger than diameter of the block.  Laser scanner and machine vision were initially seen as possible solutions for BIM level measurements. 14th May 2014Haapala Keijo

16 Q3: The width of the gap between assembled block and the host rock.  Laser scanner has still the same disadvantage that the observation process takes 5-8 minutes.  Photograph by cameras are is straight away a human readable and analysable.  If cameras are used also for other Q tasks (clean touch point surfaces, pellet filling formation capture) additional HW cost for this QA task is 0€  -> Cameras are recommended solution 14th May 2014Haapala Keijo

17 Q4: The compactness of the join between the pellets and the host rock.  The formation created in pellet filling needs to be measured to ensure that the minimum density of the bentonite buffer is reached  The main concern is that pellets may form bridges which cause empty spaces in the filling which decreases the density. In addition of decrease in buffer density it might even happen that the pellets won’t fit in the gap. In this case pellets may end up to the touch point surface.  Target resolution is size of one pellet (5 x 10mm ) 14th May 2014Haapala Keijo

18 Q4: The compactness of the join between the pellets and the host rock.  Gripper and BIM frame were studied as sensor mounting levels  Gripper mount has again the same disadvantage that part of the gap is invisible. In addition only around 30% of the area is covered by this approach if 3 sensors units are used. More coverage can be reached at the cost of increased sensors and costs. -> BIM frame level approach is recommended 14th May 2014Haapala Keijo

19 Q4: The compactness of the join between the pellets and the host rock.  Machine vision and laser scanning were studied  Both requires a rotating fixture which circulates above the gap which is filled the pellets to success in this task  Laser scanner would be a natural solution for this kind of 3D modelling task if it wasn’t so time consuming technologue.  If camera view is used also for other Q tasks (clean touch point surfaces, gap width measurement) additional HW cost for this Q task is 0€  -> Camera view is the recommended solution also for this task 14th May 2014Haapala Keijo

14th May Haapala Keijo