T2 target water leak was identified earlier this morning.

Isaac Earle, Ron Kuramoto and Keith Ng co-ordinated Meson Hall blocks removal and target flask transport.

Target assembly was removed from B/L approximately 5pm.

Vacuum "suck tube" (capacity ~ 10L) for removing water in B/L was prepared by Isaac Earle.

Approximately 5 L of water was seen in the bottom of the T2 target ladder vacuum tube enclosure, referenced by the ladder assembly locating spigot (see attached photo).

Most of the water was removed by Grant Minor, Ron Kuramoto, and Keith Ng using the suck tube, job finishing around 8pm November 22nd.

About 1/8" water remains in the bottom of the vacuum tube enclosure, which will have to be left to evaporation overnight and vacuum pumps (see attached photo).

Full suck tube was tagged and left on the north-east side of the Meson Hall blocks near TNF.

Spare target replacement, pump down and block replacement to happen tomorrow, Isaac Earle and Grant Minor to co-ordinate w/ support from Plant Group and Vacuum Group.

The suck tube vessel was drained, rinsed, and transported to the active sink area in the Meson Hall Hot Cell Lab.  There are no longer high fields from the suck tube and it is ready for future use.  The filter, tubing, and flange used for filtering the active water were removed and bagged and are currently stored in the south-east corner of the warm cell.  This bag measured up to 12mSv/hr on contact.  There are small black particles visible inside the bag.  The filtered water was sampled and will be released if approved by RPG.  The bucket with the active water is stored in the active sink boot-box area.

Photos attached.

 A water leak developed this morning from a city water supply line at a hose connection near the T2 expansion tank.  Water was observed to be dripping off the mezzanine onto the plastic sheet covering the T2 cooling package.  The leak has been stopped and the leaky fitting is being repaired by Carston Frasden.

The T2 cooling package was inspected: small amount of water on the top of the plastic sheet, no water visible below the plastic, and all package components were dry.
The T2 expansion tank level was checked: no change.

 After approval from RPG, the water drained from the suck tube, which was stored in a bucket in the RH lab active sink area, was released to the active drain.  Even after rinsing, the bucket still had a slight field from the base, so it has been labelled and will be kept in the active sink area.

Water detecting strips were installed around the T1 and T2 areas today with Doug Preddy and contractors from SMT Research.  Four sensors were installed at various locations on each cooling package.  Four sensors were installed on the top surface of the T2 monolith.  In addition, four sensors were routed for future installation at the T1 monolith (it is currently covered by blocks and requires cleaning and painting before sensor installation).

See the attached PDF for sensor ID numbers and placement specifics.

Photos are attached of the sensors installed around the T2 monolith and cooling package.

On Sep. 3^rd during the 6 hr maintenance day, Doug Preddy & I went into the 1A tunnel under “controlled access” to investigate a water leak that triggered the Water Detection Sensors.  It was also noticed that the Cu-ALCW tank level was losing water.

Water was found to be leaking down the south wall chase where the T2 water package goes up the wall. Drip rate was ~1 drip every 15 seconds.

In the late afternoon of Sep. 9^th;

Day one of the 1.5 day maintenance, the tunnel was surveyed by Fiona H. see RPG for field map & floor swipe results. 

Doug, John McKinnon & I set up a plastic sheet with a funnel connected to a 8ft. lg. poly-flow tubing to direct leaking water from the T2 into the south gutter.  This set up was left over night for the floor to dry up and resume the water leak investigation. See photos.

On Sep. 10^th;

@ 08:30 about 70% of the 1A tunnel floor had dried up and the diverted water into the south side gutter had travelled to the T1 area.

The T2 cooling package was then turned off followed by valving off the Cu-ALCW feeding the T2 cooling package. A few more strips of red tuck tape were added to secure the temporary plastic diversion sheet.

@ 11:30 the x-strip graph (T/W  MS 230) of the Cu-ALCW tank level showed that the leak had stopped and leveled off.

@ 13:15 the 1A tunnel floor had dried up with no water seen dripping from the vertical chase.  Doug also mentioned that the “water sensors” that were activated reflected this. The Cu-ALCW was then valved back on to the T2 cooling package and within 3 minutes water began dripping from the south wall vertical service chase which now appeared to about  1 drip/sec.

Fiona took a water sample (20 ml vial) from the drips and also found ~ 1000 c/m (44-2 monitor) on the tacky mat just on the inside of 1A tunnel door.  The 1A Tunnel and South TNF were then locked-up by Derek H., Violeta T. & Doug.   The T2 cooling package was turned back on ok.  Will try to repair this water leak during the Oct. mini shutdown.

On Oct 7^th, during the Mini Shutdown, the T2 cooling package was uncovered to investigate the Cu-ALCW water leak dripping into the 1A Tunnel.

The Target shield block was lifted and found that top of the monolith was dry.  Uncovering the east side of the cooling package directly above the vertical services on the south wall revealed a pin hole leak at a 1/2” 45^o copper elbow on the return line circuit of the T2 cooling package.

The cooling package was turned off followed by valving off the Cu-ALCW service lines leading up to the cooling package to let the Tunnel floor dry over night.

On Oct 8^th, the Tunnel floor was dry and Cu-ALCW service lines feeding the cooling package were drained from the Tunnel by placing a 5 gallon pail under the drain lines filling it about 1/3 full until it stopped.

Mel Good was brought in to replace the faulty elbow.  The Cu-ALCW was then turned back on with no obvious leaks.  At 16:00 approximately 1.5 hours after the repair, I went into the 1A tunnel to inspect for water leaks at the isolation valves and saw water dripping down the vertical piping on the south wall again.   

Another leak was found on the 90^o elbow just ahead of the replaced 45^o elbow. There appeared to 2-3 fine mists spraying out towards the adjacent copper elbow (look at the end of the cable tie on the following photos).

The Cu-ALCW lines leading up to cooling package were again valved off to let the Tunnel floor dry up over night.

On Oct 9^th, the Cu-ALCW lines leading up to the cooling package were again drained followed by replacing the faulty 90^o elbow. The elbow was fitted with new pieces to improve the configuration. We noticed that old copper pieces were worn thin. These damaged parts measured 20,000 c/m on the 44-2 and 40 c/m on the RM-14 monitors and were taken to the RH H/cell lab for inspection.

The T2 cooling package turned on ok about 1.5 hours after repairing the 2^nd water leak.

Mel Good received 0.03mSv over the two day repair. 

I received 0.10 mSv over three days, picking up 0.05mSv on Oct 7^th in the Tunnel where the fields were 200-300uSv/Hr by the isolation valves.  The next the day levels dropped to 40uSv/Hr.  There was no contamination found on the Tunnel floor, however 80,000 c/m on the RM14  and 50,000 c/m on the 44-2 monitors were found on the swipes taken at the bottom edge of the concrete shield blocks.

NOTE: the Cu-ALCW service lines leading up to the T2 cooling package feeds the following 4 devices; Collimator A, Collimator B, the T2 monolith cooling and the Target water heat exchanger.

This morning at 5:30am the T2 cooling package expansion tank switched to WARNING LEVEL NOT OK.  There was no change in BL1A vacuum at this time.  The change in level was confirmed by inspecting the water level visually.  Operators suggested it may have happened because the cyclotron was shut off and the temperature of all water systems dropped, however T1 did not experience a noticeable change in level, so I do not think this is the cause.  It is possible there is a leak on the cooling system somewhere, but the evidence does not suggest a leak into the vacuum volume.

At 11:55am the BL1A vacuum spiked tripping off both cooling packages.  Valve 1AV8 is closed.  There is no pumping on the T1 volume, so the pressure is slowly increasing.  T2 is at approximately 50mTorr.  Operators believe it may have been caused by work at M15 or M13.  

This appears to be unrelated to the water loss at T2, but proper diagnosis is not possible because Vacuum Group staff are away for the holidays.  The cooling packages will be left off until proper diagnosis can be performed in the new year.

Pumping was restored to 1A today by Vacuum Group and the beam line returned to normal vacuum levels.  Both cooling packages were started with no change in vacuum (no water leaks inside the vacuum volume).  The T2 package was left on for approximately 1 minute, and then the expansion tank level was checked.  Approximately 1cm of water was lost.  The T2 package was turned off, and will remain off until the package can be inspected later this week after block removal.  The T1 package will be left running until T1 MRO work begins.

The T2 cooling package was visually inspected today after blocks were removed.  With the cooling package off the following leaks were observed:

- Collimator A return line ball valve: ~ 2 drops / second
- Collimator B return line ball valve: ~ 1 drop / 3 seconds

The cooling package was then started and the following leaks were observed:

- T2 heat exchanger secondary side, north end ball valve (CuALCW):  ~ 1 drop / sec
- Target water return line ball valve above reservoir: very slow leak, wet but no drips visible

These leaks explain the water found in the tunnel, and the slow drop in T2 expansion tank level.  However it is a little mysterious why four valves all failed around the same time on two different water systems..

The copper active supply to the T2 area will be valved off to stop the leaks, and the valves will be serviced or replaced during this shutdown.

Since the previous E-Log the following tasks have been completed:

- Panel spacer rods installed at 4 locations in each tank (two top, two bottom at approximately 1/3 and 2/3 the way across)
- Spacer rods expanded only slightly to begin compressing the rubber window spacers while still leaving at least a 8mm gap between window and frame
- Window and frame around seal area masked off with masking tape
- Sealant was applied from the outside using a plastic cone tip with a copper tube attachment to allow sealant injection to the bottom of the sealant cavity.  The process involved having one person inside the tank to make sure the sealant cavity was completely filled with no voids. A total of 42 of the 20oz. sausages were required.  Two spare unopened sausages remain.

The sealant will now be left for 2 weeks to cure before water is added to the tank.

The warm cell water window tanks were filled on September 17 after 2 weeks of curing time.  A water leak was found coming from the seals of a plastic pipe joining the two tanks near the top.  This was repaired using rubber gaskets and quick cure caulking.  The tank was refilled on September 18 and no longer leaked from that location.  The sand filter was backflushed with the water exhausted to the grass area outside the hot cell lab until the water ran clear.  The pump was then started with the water circulating normally through the filter.  Small water leaks were observed coming from 3 of the 4 plastic ball valves on the filter loop piping.  These leaks stopped after approximately 3 days of continuous running, and are still leak tight now.

During this repair job it was observed that the support wheels for the warm cell manipulators are crumbling and should be replaced before the next time the manipulators are used.

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.

5 and 3 Swagelok ball valves were replaced from the T1 and T2 cooling packages respectively.

These are compression fit valves, 1/2" or 3/4" size.

1 valve in T2 was replaced previously, bringing the total # of replaced valves in T2 to 4.

Remaining valves that need to be replaced:

• T1:
  • 1x heat exchanger valve was not replaced because the heat exchanger line was not drained prior to the operation.
• T2:
  • 2x valves for the heat exchanger line were not replaced because the heat exchanger line was not drained prior to the operation.
  • 1x M8 beam blocker cooling line was not replaced for the same reasion.

Remaining valves that may need to be replaced (verify after next leak check):

• T1:
  • ~4 miscelaneous small valves (likely 3/8") were not replaced - want to check if they actually leak beforehand.
  • 2x panel mounted valves need to be inspected for leaks.
• T2:
  
  • ~3 miscelaneous small valves (likely 3/8") were not replaced - want to check if they actually leak beforehand.
  • 3x panel mounted valves need to be inspected for leaks.
  • 1x valve from the resin flask outlet has threaded connections with plumbing tape - this valve may not be leaky.

Next week, will drain all water lines associated with the cooling package before replacing remaining valves - then perform leak check. 

 (attached hand written notes)

 Update: remaining valves replaced (see: https://elog.triumf.ca/TIS/RH-Meson+Hall/320)

A trial run of remote removal of the UCN target was performed using the shielded target cask (TTA0335) developed in 2020.  The work took place between Feb 9 - 17 under work permit C2021-02-09-1.

The procedure in work instruction Document-187117 R1 was followed. Draining and purging of the water system as well as venting of helium from the target crypt was performed by Tony Hessels.  The remainder of the procedure was carried out by Keith Ng, Maico Dalla Valle, and Isaac Earle.  A maximum field of 1.7mSv/hr was measured at 0.5m from the bare target;  This is higher than the approximate 500uSv/hr field that was expected, however dose incurred during the work was minimal (Isaac: 0.05mSv, Maico: 0.03mSv, Keith: 0.03mSv).

The cask aligned well to the target arm and no modifications to the cask or UCN hardware were required to carry out the procedure.  A few updates will be required to the work instruction document based on discoveries made during the procedure; notably: 

• Cask to be installed on the west side of where the water tubing connections for the crypt flange are located;  As a result the cask lid will be installed after the cask base (with target forearm inside) is removed from the rails
• Shims are not required under blocks TTA0550 and TTA0555 in order to clear the top of the cask (the concrete and steel supports for these blocks are higher than in the UCN area shielding model)
• In addition to the six 3/8"-16 bolts for the water manifold, two shoulders screws (one on each side of the manifold) must also be removed to allow the two halves to separate

The work instruction document will be updated to include the changes above, as well as other minor updates and extra figures. 

After testing, the target forearm was reinstalled and all connections re-made.  Leak checking of the water connections and crypt flange as well as testing of the target thermocouple signals is to be arranged by the UCN Group.  The cask has been stored on top of concrete shielding on the B2 level north-east of the UCN experimental area.

Various photos taken during the procedure are attached.

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  Moved Kaon Target from storage pit to remote handling hot cell using flask as training exercise.  Safety surveyor scanned storage pit area (wide flanges: clean,  pit floor: 50cpm).  Returned flask to hot cell lab floor and covered storage pit.

Replaced T1-MK1 target ladder with the new ladder design which has an integrated upper slide plate (2 less sealing locations) and no c-seal grooves.  C-seals replaced with aliuminum delta seals.Transfered all target cassettes to new ladder in the same positions.  Performed helium leak check at interface with bellows flanges and all cassette locations.  No leaks detected.

Target still requires installation of new protect monitor.  Beam-spot and elevations procedure must still be performed.

 T1-MK1 target transferred from hot cell to storage pit position #3 to free up the hot cell in preparation for shut-down activities.

Current device locations in storage pit:

Pos 1: TNF Resin Can
Pos 2:    empty
Pos 3:  T1-MK1 Target
Pos 4:  T2-MK1 Target
Pos 5:     empty 
Pos 6:     empty 
Pos 7:     empty 
Pos 8:     empty 
Pos 9:     empty 
Pos 10:   empty 
Pos 11:   empty 
Pos 12:  Liquid Deuterium Target
Pos 13:  Kaon Target
 

Uncovered T2 monolith and transferred M20BB to hot cell using flask.

Field at 0.5m from beam blocker while being lifted with flask: 21,700μSv/hr (using pole monitor) 

Field above hole after removing M20BB: 9000μSv/hr