CEA

In order to study the operation of electromagnetic pumps with high sodium flowrates, the prospective technology for the cooling of 4th generation reactors, the R&D teams from CEA Cadarache set up a large test loop that must move no less than 400 kg of sodium at a pressure of 5 bar and a temperature of 150°C. It is an electromagnetic pump with outstanding dimensions that must move the liquid metal by using the Laplace force via coils located around stainless steel pipes. The test loop (Pemdyn - dynamic electromagnetic pump) weighs 10 tons and is installed on a metallic framework more than three meters above the ground. 

Several phenomena in play 

Cadarache exper t s commissioned Cetim to check that its vibratory behaviour will not cause any problems. “We carried out an audit of the design by working on a digital model of the installation provided by CEA. In parallel, we instrumented the test loop before it was filled up with sodium so as to determine very precisely its proper modes of vibration and check the results of the calculations”, explained Arnaud Caracciolo from Cetim, who led the project. In order to take into account the physical phenomena in play, a “multiphysics” simulation proved essential. This required the collaboration of specialists in calculation, vibrations, pressurised equipment, materials as well as heat physicists. “With the work of everyone, it was thus possible to check that the entire physics had been duly taken into account in the model”, explained Arnaud Caracciolo, who added: “the CEA model had been correctly built and it gave account of the vibratory behaviour of the system. However, we had to suggest some modifications and give an opinion on the risks related to vibrations”. Today, the test campaign has begun and, so far, no excessive vibration has disturbed the Pemdyn.