sPHENIX discussion of the superconducting solenoid

["Yip, Kin" <kinyip AT bnl.gov>]

Hi,

 

Roberto reported (email below) about a false ODH alarm which closed the LN2 supply valve and cause other damages.  The “vacuum skid”

didn’t concern us as we are not doing 2K Helium cool-down but only ~4K.  I attach the temperature profile from a sensor at the

superconducting bus and you could see when this “accident” happened --- the warm of a few K.

 

In any case, the Cryo group has shut down the (He) plant whereas the LN2 continues to cool to LN2 temperature.   They’re warming up the

Plant and hopefully, they’ll clear the “plug” (blockage) next week and cool-down the plant again.   The original plan of going to cool from

~90/100 K to 4K on Jan. 2, 2017 will not happen.  Since it’ll take a couple days to cool-down the plant itself, it’s not very likely we’ll see

4K next week.

 

I wonder whether we can do the “hipot” at ~90/100 K or so as there isn’t much contraction between 100K and 4 K anyway.

 

I also talked with Jonathan Reich and actually told what phone to “catch” Roberto.  There were actually two alarms.  He’s already replaced

the sensor in the “compressor room” which has nothing to do with the LN2 valve closing.   He’ll try to see whether he can replace the other

ODH alarm in 912 (which has been giving a lot of false alarms) next week while we’re still having cryo operation in 912.

 

Kin

 

From: Than, Yatming (Roberto)
Sent: Friday, December 29, 2017 12:27 PM
To: Yip, Kin
Cc: Orfin, Paul; Tuozzolo, Joseph E; Tallerico, Thomas N; Masi Jr, Leonard; Warkentien, Andreas F; Sardzinski, Mark A; Lederle, Dewey L; Talty, Patrick; Van Kuik, Brian; Soria, Victor
Subject: ODH ALARM 912

 

Kin,

 

We had an ODH alarm event in 912 around  overnight.

Shutdown the LN2 supply valve [automatic] into the bldg. to cryo plant and sPHENIX LN2 cooler.

 

The fans kicked on in the compressor room and temperature dropped sufficient and the water lines in the compressor room and water/oil heatexchangers on the vacuum skid cracked. The water tower eventually tripped on low water since the water was not returning to the tower.

Sullair helium compressor for the cryoplant tripped.

System is restarted but the cryoplant is not performing.

I have inlet pressure but the cold end of the plant and expander have to high inlet pressure.

Appears  I have plug in the plant.

So shut down plant.

 

We have next week to get the plant back up.

 

Roberto

 

 

 

 

Attachment: 2017-12-29.jpg
Description: 2017-12-29.jpg