Engineering Operations OH water leak: Water leak is located ~ 4.5” into the upper OH lead. Leak 2 o’clock Cooling hole in. dia.

Engineering Operations OH water leak: Leak first seen between conductor & Insulation

Engineering Operations OH water leak repair preparation: The upper TF hub disassembled to provide access. Repair Area

Engineering Operations OH water leak repair options: The mechanical and leak repairs will be addressed separately. A pin-hole leak can be repaired with a leak sealer. For a crack, the cooling hole will be reamed to a larger diameter to accommodate a cooling sleeve. An O-ring at the end of the sleeve will be compressed at the end of the reamed hole ” 0.394” OH Conductor

Engineering Operations OH stress crack repair (IF REQUIRED): A copper bridge secured to the conductor and lead block using either clamping or a TIG-braze. Stitch TIG- Braze 1/8 “ fillets around support block to lead block TIG- Braze 1/8 “ fillets around support block to conductor Copper support block fits snuggly around conductor and attaches to lead block OH Center

Engineering Operations OH Lead mechanical support: A G-10 block added to support vertical and twisting loads.

Engineering Operations Insulation repair: Epoxy/glass ground wrap around both conductors Turn insulation on lower conductor untouched Kapton insulation added to repaired conductor G-10 spacer between conductors

Engineering Operations Post repair monitoring: Sight tubes added to allow periodic (daily?) inspections w/boroscope. Leads can be brought out to electrically monitor the resistance of the conductor or the flex link A leak divertor with an electronic water monitor is possible.

Engineering Operations LLD Heating: A “house air” heater to heat the 4th LLD plate has been assembled in the VPL and tested to 12CFM at 300C.

Engineering Operations Updated FY10 Schedule: NSTX has completed 2 weeks of the planned 15 week run. We expect to resume operations on May 24th, but could be ready a week earlier based on the scope of the repair. Assuming a maintenance week each month, NSTX will need to run into September this year. Need to determine the scope of the upcoming outage. A timely start to the FY11 run is needed to support an aggressive NSTX upgrade schedule.