Hello all,

We decided to soak the vessel last night rather than ramping down.

At 8:30 AM after a 24 bakeout, we began the ramp down.

50F/hour at first and then 90/hour once we saw that it was coming down fairly evenly.

The port 4’s and the VVSA end flanges lagged behind by about 30F.

We removed the insulation on the end flanges to allow heat to escape.

Their heaters are still active to keep things balanced as needed.

The upper belly region staying pretty much with the vessel average.

As of now we are at about 325F on the vessel and 200F on the ports @ 9x10-7 Torr

The ports are turned off now to let them come down as far as possible and minimize risk (see below).

We are continuing the cool down in 50F increments to keep the vessel even within 30F.

 

This morning another heater overshoot occurred on a port 10.  

The port tube reached about 555F.  The flange was estimated to be around 220F.

I asked Major Tool to bring in another controller box to back up the existing ones and improve the zone allocation on the ports but a unit is not readily available.  Therefore I spoke with Jim Flanagan to convey my concern and the risk involved.  We now have 4 heat related NCR’s.  He said that the options available were limited (control boxes are not available for several days) and he would place additional resources to oversee the ramp up tonight and personally check on the vessel status as well.  I also asked them to call me when the ramp up is ready to begin tonight.

 

Depending on the success of tonight I may return tomorrow afternoon.

 

Thanks,

Mike Viola, PPPL, (609) 243 3655