Cooling of pulse heated canned rods

The European Spallation Source (ESS), being designed and built in Lund, Sweden, will be a 5 MW long-pulse neutron spallation research facility. At the heart of the facility is the solid rotating Tungsten target, which converts high-energy protons into neutrons for delivery to a suite of research instruments [4]. The preferred option for the primary cooling system for the ESS tungsten spallation target is helium, but water cooling is investigated as a backup solution. In the baseline configuration for the water cooling backup solution, Tungsten rods are fitted into sealed Zircaloy or Stainless Steel cans. The rods are placed vertically in cross-flow configuration within sectors of a rotating target wheel, which has a similar steel envelope as the wheel in the preferred helium cooled option. This presentation contains investigations of the internal heat transfer in and between the rods and cans, during the proton pulses. The details of the external heat transfer from the can, into and in the water are investigated elsewhere.