User name jpchen
Log entry time 23:15:42 on July17,2005
Entry number 148389
keyword=Helium target vented due to fan stop. Refilled. All is fine now
I was called in at ~20:20. TO (Wilson) informed me that the target loop 1
(Helium) fan stopped by itself, and the target pressure then dropped to 1 atm.
Wilson turned fan back on and turned High popwer heater off.
I came in, turned down coolant. Asked for controlled access.
Appearantly due to the fan off, part of the target warmed enough to have
pressure exceeded the vent pressure (normal operation is ~200 psi, vent at 230
psi), After reset the vent volve, we added helium 4 gas back slowly until we
get back to 200 psi and 6.4K
All is fine now.
Mike Seely stopped-by in the middle helped with switching a gas bottle. There
are still two full bottles helium in the hall
(enough for one fill).
For future reference, next time, it's better to turn down
coolant to reduce heater load, since turn off heater would make
the loop sub-atomsphere.