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Virgo Runs (O4c)
berni - 6:52 Sunday 29 June 2025 (67159) Print this report
Operator Report - Night shift

ITF found in Trobleshooting mode; the IMC issue was just resolved and lock acquisition was just started.

The ITF reached Science mode at 21:47 UTC but it unlocked at 22:18 UTC. At the next relock I realized that the fmoderr was skipped (fmoderr_skip = True in the ITF_LOCK.ini file); I reactivated it.

Then the ITF collected multiple unlocks at CARM_NULL_1F because of DIFFp loop oscillation; at 23:10 UTC I set Troubleshooting mode and I contacted the ISC on-call (Julia). She was able to fix the problem, the ITF survived to CARM_NULL_1F and Science mode was set at 0:09 UTC.

The ITF unlocked at 2:14 UTC, Science mode set at 2:56 UTC.

 

Vacuum

At 3:00 UTC the guardian reported that the vacuum tank at WE was leaking nitrogen; on the DMS the problem was hidden by by a flag that was already red. I contacted the Vacuum on-call; at around 4:00 UTC he came on site and he performed and he verfied thestatus of the plant; the problem will be fixed tomoroow.

 

Guard tours (time in UTC)

23:00-23:40; 2:30-3:10

 

Oncall events

ISC
(29-06-2025 01:00 - 29-06-2025 02:00) From remote
Status: Ended
Description: DIFFp loop oscillation in CARM_NULL_1F
Actions undertaken: Tuning the proper gain

Vacuum
(29-06-2025 06:00 - 29-06-2025 06:30) On site
Status: On-going
Description: check the level of nytrogen at WE

Images attached to this report
Comments to this report:
Vacuum, Pasqualetti - 12:09 Sunday 29 June 2025 (67161) Print this report

This night, around 2 AM local time, the relief valve of the WE external LN2 tank opened due to the tank pressure increasing to about about 3 bar. The tank LN2 content was then released. The event is confirmed by the safety valve that was found still open in discharge mode and by the analog gauge on the tank, showing about 3 bar.

The event was not traced by the remotized gauge, apparently below 2 bar, reason to be checked.

The overpressure event is linked to a problem with the tank poor insulation, which causes the inner pressure increasing. This morning we partially fixed the issue by installing a vacuum pump to improve the insulation vacuum: the insulation vacuum level is now back to 1 mbar. The pump must stay always ON and kept monitored. We keep the system running with the remaining LN2 and have asked the supply company for an emergency refill as soon as possible, normally tomorrow morning. We will coordinate with the control room for this operation.

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