All filters were replaced for the T2 cooling system: demineralizing resin circuit and target water system.

The T1 cooling system was refilled with water via the expansion tank until the tank level read approximately 38 cm.

The system pump was restarted. All sensors displayed acceptable nominal values. Demin flow was tuned to 1.0 gpm.

 No leaks or abnormalities observed - system running normally.

NOTE: the needle valve for demin flow control adjustment was behaving strangely - it needed to be tapped when loosening to increase flow in order for results to be observed. Suggest replacement next shutdown (2023) - a calendar reminder was set to do this.

The T2 cooling system was refilled with water via the expansion tank until the tank level read approximately 38 cm.

The system pump was restarted. All sensors displayed acceptable nominal values. Demin flow was tuned to 1.0 gpm.

No leaks or abnormalities observed - system running normally.

An attempt was made to actuation the T2 profile monitor, however it showed up in EPICS as being not present. Furthermore, the "Remote" indicator light on the physical controller was not lit up despite the switch being in remote mode. The limit switch indicator light was working.

Upon troubleshooting with Erwin Klassen, it was determined that a jumper was missing on the profile monitor control connector (on the target end, rear of bulkhead). The jumper shorts pins A and G on the mil-spec connector on the controller end, which is for 120 VAC supply, to indicate that the device is connected. T1-MK1 was checked - this jumper was present on T1-MK1, across pins E and F of the mil-spec connector, but was not present on T2-MK1. Otherwise the connectors were identical. It is suspected that it was accidentally omitted during maintenance in the past. Regardless, a new jumper was soldered in-place on T2-MK1 across pins E and F to replicate T1-MK1. The system functioned normally after this.

Attached photo shows the completed solder job - the current state of the connector on the rear side of the target bulkhead panel.

Mechanical Services Group changed the pre-filter in the ventilation system on Aug. 29, 2022 as per work permit C2022-08-29-2.

It is recommended that Mechanical Services change the HEPA filter as soon as possible. These filters are on order with approximately 7 month lead time. 

Edit: as of 2023-05-03, the HEPA filter has been changed.

The following maintenance tasks were performed during mini-shutdown of 2022 with the goal of resolving the Fault 14966 (target water flow rate low).

• Replace the o-ring, paddle wheel, and shaft on the following flow rate sensors:
  • Q1 (FGTGT)
  • Q2
  • Q4
• Replace the demineralizing flow metering valve with a new needle valve (the old one was flaky and appeared to occasionally restrict flow)
• Re-tune the demin. flow to 1.15 gpm
• Top up the expansion tank due to water loss during the maintenance job (from 27.1 cm level to 34.8 cm)

To test the theory that the demin. flow metering valve was faulty and had an effect on the target water flow rate during operations, the valve was closed to determine if it stopped flow to the target. The result is that it did not, and only flow in the demin. circuit was affected. Therefore, it is likely that the root cause of Fault 14966 was not due to the demin. metering valve, but rather an issue with the pump, heat exchanger, pressure in the lines, or another form of obstruction. It should be noted that when the pump is turned off, all flow rate and pressure sensors drop to zero (except the pressure sensor located in the BL1A Service Tunnel) - so if the fault occurs again and symptoms show this case, it is likely that there is an issue with the pump intermittently turning off or similar.

As an aside: it is recommended in the future when changing circuit boards on the flow rate sensors to use metal screws instead of the plastic screws supplied with the parts.

Dose rates observed in the work area: 300-500 uSv/h at the target cooling package area, 1300 uSv/h at the target monolith area.

A fault was reported June 21, 2022 (Fault 15033) regarding T1 inlet pressure warnings... the pressure reading slowly dropped over time as seen in the attached strip tool screenshot (B1A:T1CS:PGIN). The pressure reading issue is attributed to a fault pressure transducer. The transducer was replaced on Oct. 11, 2022 my M. Dalla Valle. It is currently functioning as expected and the system is operational.

Upon uncovering the T1 and T2 areas to prepare for regular cooling package maintenance, it was discovered that multiple ball valves were leaking. Primarily the Swagelok SS-45S12 parts, but some SS-45S8 parts have failed as well. There were small puddles of water underneath many of the valves. It appears that the leak is due to a compromised seal. It is suspected that these parts failed from radiation exposure. They have PTFE packing material which is highly susceptible to decomposition under irradiation, and as far as we can tell they have not really been repaired/replaced (aside from a written note on one saying the seal was changed in 1997).

It is recommended to add the regular repair/replacement of these valves to the annual shutdown MRO checklist.

Once replaced, this e-log will be updated to document which ones were replaced.

T1 Cooling Package MRO began Jan. 16, 2023.

The following maintenance tasks have been completed for T1 (this list will be updated as work progresses):

• Drained water
• Hansen fittings o-rings inspected: OK
• Replaced demineralizing flow metering valve (part number SS-8BK*)... this part was replaced because the equivalent part on T2 exhibited potential signs of wear during 2022 and was replaced in 2022 mini-shutdown (October). There are two things to note about this part: 1) when loosening it, it makes an audible *click* at some point during loosening rather than a smooth continuous feeling like the new replacement part, and 2) it appears to have originally been installed backwards in terms of the flow rate direction arrow. It is now installed correctly.
• Demineralizing resin can - exchanged with fresh resin (2023-01-18... dose rate of old resin which is currently located in the warm cell is approximately 40 uSv/h on contact)
• Replaced filters:
  
  • Target water CUNO filter (it was relatively clean)
  • M15 CUNO filter (it was relatively clean)
  • Demineralizing 90 micron filter (it was very dirty with tiny pieces of debris)
• Replaced leaky valves (see e-log 318 and 320)
• Refilled expansion tank water (see e-log 321)
• Tuned demin flow rate to 1.1 gpm, turned on pump [2023-03-06], confirmed system functionality (all sensors OK, no water leaks observed). See screenshot attached of T1 state at approximately 4:00pm on 2023-03-06 after the system had been running for a significant time.

As of now, the cooling system is ready for beam. Prior to beam-on, actuation tests of key items such as the target ladder and beam blocker need to be performed. It is expected that this will be done within the next 1-2 weeks.

T2 Cooling Package MRO began Jan. 16, 2023.

The following maintenance tasks have been completed for T2 (this list will be updated as work progresses):

• Drained water [2023-01-16]
• Replaced ball valve located between heat exchanger and target flow sensor FGTGT (part number SS-45S12)... this part, as well as numerous other ones, were noted to have been leaking. See e-log 308
• Replaced both CUNO filters (target water and demin. resin circuit filter) [2023-02-01]
• Replaced 90 micron demin. filter (the filter was very dirty - it was last changed in Feb. 2012 as indicated by written note) [2023-02-01]
• Inspected Hansen fittings (o-rings look OK) [2023-02-01]
• Replaced o-ring, shaft, and paddle wheel for flow sensor FGSEC (Q3). The old paddle wheel had significant wear in the shaft hole which resulted in sensor readback issues observed during 2022 operation. It is likely that this was caused by debris or a manufacturing defect which got worse over time. Photos show a comparison between old and new. [2023-02-01]
• Replaced leaky valves (see e-log 318 and 320)
• Refilled expansion tank water (see e-log 322)
• Changed M20 beam block o-ring seals, and performed vacuum check (see e-logs 319, 324, and 323)
• Tuned demin flow rate to 1.1 gpm, turned on pump [2023-03-06], confirmed system functionality (all sensors OK, no water leaks observed). Note: target water conductivity sensor (CONDTGT) took a few hours to ramp up to appropriate value. See screenshot attached of T2 state at approximately 9:15am on 2023-03-07 after the system ran overnight.

As of now, the cooling system is ready for beam. Prior to beam-on, actuation tests of key items such as the target ladder and beam blocker need to be performed. It is expected that this will be done within the next 1-2 weeks.

The CUNO filters were changed 2023-01-17 for:

• BL1A Holding Tank drain output, adjacent to the pump
• RH Active Sump, adjacent to the V2 valve

Both of these filters are in-line with the drainage lines from the BL1A holding tank to the active sump. It was suspected that they have not been changed in many years, if ever. Prior to changing the filters, the maximum flow rate measured from the Proteus paddle wheel sensor during draining was around 0.85 gpm (the draining procedure document indicates it should be between 0.9 to 2.5 gpm). After replacing both filters, which each showed significant clogging of sediment, the flow rate significantly increased and the maximum of 2.5 gpm was achievable. Note that when the drain pump was initially turned on, it took some time to reach the desired flow rate due to air in the water lines - the flow rate was quite low until the lines were once again filled with water.

It is suggested that these filters should be replaced every ~3-5 years, depending on usage, or otherwise as-needed (it is possible to see through the clear walls and determine how dirty they are). This MRO item will be added to the checklist of routine T1/T2 related tasks performed to prevent flow rate issues in the future during draining.

Filters were bagged and discarded as active waste.

Attached photos show old filter in bucket, and newly replaced filter, for the RH Active Sump.

Maico/Eric/Albert:

The expansion tank in T1 was filled to ~36cm in the morning.

We contacted the control room to test flowrates in the T1 cooling loop after new installation of resin in the demineralizing line.

Epics interlocks tripped immediately as pump was turned on (flow too low or pressure to high) due to new resin.

Turning on the pump repeatedly extends the delay before system trips, until eventually the pump can run continuously. 

Flowrate through demin line initially too high (~2.5 gpm), adjusted flow control valve to bring it to ~1.4 gpm (setpoint at the time ~0.4-1.5 gpm).

When the pump was turned on initially, saw physical pressure gauge (dial type) bottom out/make greater than 1 full rotation (>50 Psi). 

No connection between the physical dial to EPICS so no cause for immediate concern.

All valves are more leaky than when the pumps are off - leaks definitely not due to depressurization. 

Attached: photo of the likely 'faulty' dial pressure gauge. 

Water reservoir in T1 started draining at ~7.30 am, will leave till tomorrow or overnight to fully drain. 

(Preparation to replace all leaky valves). 

Drained water samples collected for RPG. 

A 0.75" SwageLok ball valve that was taken out from the T1 cooling package was inspected (SS-45S12).

All valves in the T1/T2 cooling packages likely leaked due to damage to plastic/rubber sealing components. 

SEE PICTURES ATTACHED.

We can see that some bits of white plastic, possibly a bushing, has disintegrated and is leaking out from the valve shaft.

Additionally, there is a considerable amount of dirt/grit in and around the ball.

The surface of the valve opening exibits visible signs of wear (new valve opening is perfectly smooth).

Finally, a red-colored material is found on some small stainless steel parts which is either buildup from contaminants in the line or worn silicon/rubber lining.

Hypothesis: 90 um filter which had not been replaced caused the water in the line to build up particulates and wear plastic/rubber parts in the valve, causing them to leak. 

From the previous test (ELOG 315), we know that the leak is not due to depressurization.

The M20 beam blocker was moved from the T2 monolith to the meson hall hot cell with the remote handling flask (completed ~4pm).

This operation was performed in preparation for M20 maintenance (main shaft o-ring replacement + air cylinder re-lubrication).

RPG surveyors measured 20,000 CPM from swiping the surface of the beam blocker shaft, and measured 25 mSv/hr on contact with the beam blocker.

Fields on the hot cell roof were at 100 uSv/hr at 0.5 meters from the top of the M20 BB. This should reduce drastically with the introduction of lead blanket shielding (see attached pictures). 

3x 3/4" swagelok ball valves (2x at T2 and 1x at T1) were replaced after the water cooling line was shut off at the BL1A tunnels late yesterday. 

We were able to relieve pressure from the T2 water cooler + M8 colA/B (they are the same line) at the BL1A tunnel through a drain port but no such port exists for the T1 heat exchanger line in BL1A.

The T2 heat exchanger line was virtually dry at the replaced valves after pressure was relieved.

The T1 heat exchanger line was still pressurized but while looking for a suitable port to drain at the cooling package, one of the copper fittings at the 1/4" heat exchanger line broke off at the connection to a green valve. 

~1L of water dripped from this line and this was sufficient to relieve pressure from the T1 heat exchanger line - allowing for the 3/4" ball valve to be replaced. 

Until the green valve gets replaced, the T1 heat exchanger line must remain shut off in the BL1A tunnels as the broken copper line is not plugged currently.

Update (last picture): the green valve was replaced with an equivalent 1/4" swagelok ball valve. We also incorporated two 90 deg. bends in the copper tubing to help relieve any stresses that may develop.

I have refilled the water package on T1 with DI water. The Expansion Tank is at 37cm. This may change when pump is turned on.

I have filled the water package on T2 with DI water. The expansion tank is at 38.1cm. This may change when the pump is turned on.

 We moved M20 back to the T2 monolith and re did the connections for air + limit switches + T2 profile monitor air.

Note: T2 profile monitor electronics sparked when we moved M20 out initially. (Update: Shengli Liu from probes group performed a test on the T2 profile monitor electronics on Mar24 and found that they are working properly)

M20 started leaking when we tried to bring it to vaccum - from the monolith o ring seal and not the main shaft seal - will look to correct on monday.

Verified through measurement that the replacement o ring was the correct size (#268 0.139" diameter compared to the 0.131-0.137" that was remved - likely shrunk over use).

Update (Mar 06, 2023): M20 was lifted ~5 in above the monolith flange and we identified that the leak was caused due to damage to the o ring (image attached).

The o ring likely damaged when M20 was brought into contact wit the monolith flange, lifted up again, and brought down for a final time before vaccum check.

The above procedure was done because the flask tends to stall close to the lowermost position and prevents unlatching unless lifted systems are lowered fully.

This will be noted in updated procedures.

 T1/T2 valves were not leaky still (only a few droplets) - pending T2 cooling system pump on for final leak verification.

 We tested the actuation of the M9/M20 beam blockers on the T2 monolith (3-4pm).

Vacuum levels remained steady throughout so the M20 o-ring replacement that was performed this shutdown was successful (see strip of 1ACG4 - vacuum gauge for T2 systems interlock).

Note: M20 was actuated by contacting the control room, while M9 (labeled T2 blocker) was actuated through the physical ASU on the ground level of the meson hall (see picture).

For future shutdown work: the air supply valve must be kept open (tab lifted up), otherwise the solenoids won't see pressurized air. 

We ran into issues because the tab on the valve broke early into the shutdown and we didn't realize that it had to stay in the open position. 

Note: The flow on the T2 demin line went up to 1.5 gpm yesterday when we were on the blocks. The needle valve was likely nudged on accident.

Update:

1) the T2 demin flow was corrected and the air supply tab was replaced - see picture M20

2) T2 BB actuated successfully with replacement tab - vacuum remained stable

3) slow leaking valve connections were tightened again

4) water level in expansion tank corrected to just below 40 cm