On September 18th installation of nSiC#1 was attempted on TM2. As usual, new fasteners were tested previous to insertion into hot cell and employed during installation. the last fastener to be installed was for the circuit D block. The fastener/air ratchet stalled immediately indicating a problem. The fastener was removed and a an attempt was made trying a new spare fastener. That fastener also jammed right away but could not be removed or installed any further.
A breaker bar was employed to achieve more torque and the fastener was able to be loosened, although it would not come completely out, dangling and wobbling like it was free. A claw type bar was used to add slight pressure to the fastener while it was loosened allowing the fastener to undo the rest of the way.
Target was removed and discovered that that insulator supporting circuit c and d blocks was quite broken and that a few chunks had fallen off. It was also notice that boefore the breaker bar had been employed that a piece of ceramic was on the table suggesting that the ceramic had been at least partially broken at the time of removal of the previous target. Also, the threads of the insert for circuit d showed damage an swarf.
Swarf was vacuum claned out of the circuit d thread insert and a machine tap ran through the insert twice.
nSiC#1 was reinstalled with new waterline gaskets and new c and d circuit fasteners with a little bit of the first 2-3 threads lightly coated with vacuum grease.
High current fasteners torqued to 130 in lbs. |