Absorber progress MICE-ISIS review of the liquid hydrogen system will be held in early January; guidance from Nominated Engineers on the imported absorber vessel and windows is required as an input to that review AN/SW – find out and document the design, working and test pressures for the vessel and window assembly Note that in the event of a catastrophic vacuum failure and violent liquid boil-off, the integrity of the pressure relief line(s) is the limiting factor, not the strength of the vessel or windows, which are not designed for that resultant pressure SW – provide a simple schematic of the pressure relief tract, with linear distances and hydraulic diameters as part of review material MC – ask David Jenkins for advice on speed of pressure build up resulting from violent liquid boil-off AN/SW – revisit any calculations or tests already done by MICE on the above and try to converge AN/SW/MC – arrange tour of MICE hardware when convenient for Mo prior to review AN – make one last attempt to get the declaration of conformity from KEK SW/AN – clear up any ambiguity over the possibly redundant annular volume around the vessel wall

Replacing hydride bed with bottle Assumptions Baseline plan is for 2 absorber fills Outcome from R&D was that each bed charge would last 2-3 fills before needing topped up Advantages No risk of diminished bed capacity Following jobs no longer necessary Move pressure gauge Replace cracked rubber tubing Reinstate glycol line with drain Purchase expansion tank Replace hydrogen regulator Reinstate auxiliary chiller Purchase more glycol coolant No icing/condensation collection inside gas panel Quicker empty procedure Disadvantages Each fill operation needs 2 hydrogen bottles Each empty procedure will result in lots of hydrogen gas being vented Spare H2 bottles must be stored in case of emergency vent New control sequences need to be written

Hydrogen fill procedure

System under vacuum after purge, H2 bottle connected

Hydrogen fills charging line up to control valve

Hydrogen liquefied through control valve loop

Bottle empty, switch valve to second bottle

Hydrogen fills charging line up to control valve

Absorber filling

Absorber now full

Vac out charging line

Pressurise with helium

Prepare for empty

Hydrogen empty

System ready after fill

Open N2-purged vent line

Use heater to boil off hydrogen

Absorber empty, open bypass valve

Pump out remaining hydrogen

System clear

Charging line design

Charging line design

Review