On Oct 7^th, during the Mini Shutdown, the T2 cooling package was uncovered to investigate the Cu-ALCW water leak dripping into the 1A Tunnel.

The Target shield block was lifted and found that top of the monolith was dry.  Uncovering the east side of the cooling package directly above the vertical services on the south wall revealed a pin hole leak at a 1/2” 45^o copper elbow on the return line circuit of the T2 cooling package.

The cooling package was turned off followed by valving off the Cu-ALCW service lines leading up to the cooling package to let the Tunnel floor dry over night.

On Oct 8^th, the Tunnel floor was dry and Cu-ALCW service lines feeding the cooling package were drained from the Tunnel by placing a 5 gallon pail under the drain lines filling it about 1/3 full until it stopped.

Mel Good was brought in to replace the faulty elbow.  The Cu-ALCW was then turned back on with no obvious leaks.  At 16:00 approximately 1.5 hours after the repair, I went into the 1A tunnel to inspect for water leaks at the isolation valves and saw water dripping down the vertical piping on the south wall again.   

Another leak was found on the 90^o elbow just ahead of the replaced 45^o elbow. There appeared to 2-3 fine mists spraying out towards the adjacent copper elbow (look at the end of the cable tie on the following photos).

The Cu-ALCW lines leading up to cooling package were again valved off to let the Tunnel floor dry up over night.

On Oct 9^th, the Cu-ALCW lines leading up to the cooling package were again drained followed by replacing the faulty 90^o elbow. The elbow was fitted with new pieces to improve the configuration. We noticed that old copper pieces were worn thin. These damaged parts measured 20,000 c/m on the 44-2 and 40 c/m on the RM-14 monitors and were taken to the RH H/cell lab for inspection.

The T2 cooling package turned on ok about 1.5 hours after repairing the 2^nd water leak.

Mel Good received 0.03mSv over the two day repair. 

I received 0.10 mSv over three days, picking up 0.05mSv on Oct 7^th in the Tunnel where the fields were 200-300uSv/Hr by the isolation valves.  The next the day levels dropped to 40uSv/Hr.  There was no contamination found on the Tunnel floor, however 80,000 c/m on the RM14  and 50,000 c/m on the 44-2 monitors were found on the swipes taken at the bottom edge of the concrete shield blocks.

NOTE: the Cu-ALCW service lines leading up to the T2 cooling package feeds the following 4 devices; Collimator A, Collimator B, the T2 monolith cooling and the Target water heat exchanger.