The blocks above the pre-separator section of the ISAC beam lines were removed today in the Target Hall by Bevan Moss and Chad Fisher with Lynne LeMessurier present from RPG.

The two blocks in the layer below the top layer above the pre-separator were damaged on removal (see attached photos).  This was due to an attempt to lift them in the incorrect sequence caused by misinterpretation of the labeling / numbering system drawn on the top of the blocks.  The blocks are labelled for the replacement sequence, but not for the removal sequence.  An attempt was made to lift a block that had an overlap with an adjacent block that was not visible, causing damage to two blocks.  A note was added in black marker to the critical block to indicate that it should be removed last (shown in attached photo).  The block replacement sequence will be photographed and a procedure document will be written by Bevan, with a bound copy of the procedure provided in the Target Hall, in order to prevent such an incident from occurring again.  Broken pieces of the blocks were collected and placed in a 5-gallon pail.

The removal of all of the blocks caused the depression in the target station to fluctuate around the trip point (17 inches of water column), which caused the ventilation alarm to trip on and off constantly.  Operations contacted me to ask if this could be remedied.  Bevan closed the damper to ITW, which brought the depression to a low enough value so that the alarm could be defeated properly.  This was around 2pm.

Preliminary co-ordination of the ITE Harp 9 removal job was discussed by Scott Kellogg and Ron Kuramoto around lunch time.  Keith Ng (RH) and Scott searched for the blank-off that was used during the last Harp 9 repair (removed from B/L in March 2013) but they could not locate it.  I was later able to find the blank-off bagged in a grey rubbermaid bin at the bottom of the stairs in the target storage vault pit (under the SHC / NHC ventilation and filters).  The blank-off was found bagged and tagged as surveyed at 100 counts @ 0.5m on March 27, 2013.  I gathered Scott, Ron Kuramoto, and Danka Krsmanovic to co-ordinate the Harp 9 removal and blank-off installation, starting at around 2:30 pm.

For the Target Hall Harp work, Ron Kuramoto and Scott prepared the required tools and plastic coverings / bags.  I acted as crane operator.  Danka was the surveyor present.  Anders Mjos joined the group for photos and moral support.

Scott disconnected services from the Harp device, and prepared it for lift.  I called operations to confirm that the section of B/L had been vented.  Ron and Scott used the RH tools to disconnect the 2 vacuum flange bullet bolts.  Ron directed the crane with signals and I lowered the chain rigging to the Harp, it was connected and removed from the BL with the main hoist.  (I made the mistake of directing the rigging of the harp to the main 20T hoist, when in fact the 3T Aux hoist should have been used, as the main hoist can't reach to the vacuum / storage pit on the west side of the hall.)

Danka performed several swipes and measurements of the Harp after removal.  Alpha contamination was discovered on the bottom of the Harp flange.

Ron and Scott installed the blank-off flange, then I called operations to indicate that pumping should start.

Ron and Scott retrieved the vacuum test flask jig / support structure from the West storage pit and brought it down to the pre-separator pit.  I lowered the Harp into this flask jig, and Scott used the side-wall location bolts from the top of the harp assembly to fasten the flanges of the Harp and the jig.

I had trouble at first activating the Aux hoist but soon realized that it's necessary to press the Aux pendant "ON" button down for several seconds before the power actually turns on to this hoist.

We then removed the main hoist hook and attached the Aux hoist to the Harp / flask.  The assembly was transported to the West storage pit.

Some of the handrails had to be removed to facilitate initial movements of the Harp assembly.  These handrails should be replaced tomorrow morning.

Scott also submitted a Work Order for a back-up blank-off today, job number 40303.

The pre-separator blocks have NOT been replaced yet, we will do this tomorrow morning.

It was a busy day, thanks to all for their efforts and for staying a bit late to get the blank-off installed.

Best regards,

Grant