Activation analysis of the water cooling system of the LIPAc beam dump

• Quantification of radioisotope production in the water cooling system of LIPAc.
• Design requirements to fulfill dose rate targets.
• As main conclusion: water filters may be placed outside the accelerator vault, requiring only moderate radiation shielding.

LIPAc stands for Linear IFMIF Prototype Accelerator. LIPAc generates a 9 MeV deuteron beam, which is stopped at a beam dump, depositing over 1 MW of thermal power. A water cooling system has been devised for extracting this energy while keeping operational temperatures within range. The existing high neutron fluxes in the beam dump during operation produce activation of both coolant and beam stopper, which also suffers from corrosion into the coolant. The presence of radioisotopes in the cooling water leads to a radiological hazard.Water purification systems are located outside the accelerator vault and accumulate activated products during filtration, requiring a specific radiological shield to comply with target dose rates. Also devices containing large volume of activated cooling water, like N-16 decay pipes, require specific radioprotection analysis and design. This work identifies the most relevant radiation sources due to the activated cooling fluid, which may result in radiation doses to workers, and propose radioprotection measures into the design to mitigate their effect.