Dimensioning the EVITA semi-open loop at BR2 for qualification of full size JHR fuel elements

The Jules Horowitz Reactor (JHR) is the next generation research reactor from CEA and which commissioning is foreseen in 2014. Prior to acquiring the exploitation license, the fuel elements have to be qualified for their intended functioning power. The only facility capable to perform this task is the Belgian research reactor BR2, due to its similar thermal-hydraulic parameters. At the moment, one has already tested the fuel plates separately. The preparation of the JHR safety report still needs the test of full size elements. HR fuel element is broader and more powerful than a standard BR2 fuel element, and one cannot perform an irradiation by simply interchanging them. However, BR2 has 200 mm channels at its disposal, which can be adapted to give the correct hydraulic diameter. One also needs an additional pump to deliver the necessary cooling flow rate for the higher power. aper describes the dimensioning of the EVITA semi-open loop, which has been built at BR2 to irradiate full size JHR fuel elements and qualify them for the foreseen exploitation parameters. One explains here the followed methodology to quantify the required additional head for the booster pump and to determine the pressure profile along the circuit and the safety margin on the fuel. This methodology relies only on a priori calculations without any measurement on full size installation subpart as usual before the assembly in controlled zone. The article also explains how the original JHR thermal hydraulic safety calculation scheme was adapted to the BR2 environment. One also compares the measurement results on the fully built installation with our previsions. Our models compare well with the experimental results, excepted for the pressure loss on the fuel plates.