%20autour%20et%20dans%20un%20dispositif%20en%20r%C3%A9flecteur%20-%20carr%C3%A9.png "Evaluation du flux thermique (n.cm-2.s-1) autour et dans un dispositif en réflecteur - carré © IRESNE/CEA")
The Jules Horowitz Reactor (JHR), currently being built at the CEA Cadarache centre, is an experimental facility that will be used to test the behaviour of materials and nuclear fuels under irradiation using various experimental devices. To prepare the experiments to be performed with these devices, a series of multi-physics studies are being carried out by JHR Section teams in the fields of neutronics and thermohydraulics.
Neutronic calculations are used to determine certain specific characteristics such as nuclear heating or neutron fluxes. These characteristics provide information on the reactor performance and its impact on the devices, thereby highlighting any changes to be made to optimise its design. Figure 1 illustrates the optimisation of the neutron shielding for a device positioned in the JHR reflector to attenuate the thermal flux and thus achieve the required ratio between the fast flux and the thermal flux.
The thermohydraulic calculations take into account the nuclear heating calculated on the basis of the neutronic calculations, the coolant properties, and the device’s design. The results are then used to check that the materials are being cooled correctly; for example, Figure 2 shows the temperature range in a structure of the device. They are also used to check the device’s operating point and the possible adjustments needed so the experiment corresponds to the initial specifications.