Accelerometers data processing for boiling onset detection on the LIPAc Beam Stopper

Abstract

The LIPAc (Linear IFMIF Prototype Accelerator) is a prototype that ends in a dump made of copper with conical shape and cooled by water moving at high speed on the outer surface. In case the beam reaches the dump with abnormal misalignment or offset, the local temperatures at the water-copper surface will give rise to boiling onset which can be used as a warning flag before an excessive thermal stress distribution could endanger the mechanical integrity of the Beam Dump. Previous experiments having the same goal were carried out with hydrophones to detect the onset of boiling [doi:10.1016/j.fusengdes.2015.01.011]. The current article deals with the treatment of the signal coming from an accelerometer. The article will go into detail of data treatment to refine the detection of the boiling onset, even if noise coming from external or undesired sources is mixed with the boiling signal, which prevents in this case the use of the RMS as a monitoring parameter. Recommendations are given for the implementation in the cooling system of the LIPAc Beam Dump to be installed in Rokkasho.