Analysis of the AMMON Experimental Program in the EOLE Facility Supporting the Qualification of the JHR Neutron and Photon Tools

The first criticality of the international Jules Horowitz Material Testing Reactor (JHR) now under construction at CEA Cadarache, is planned by the end of the decade. In order to perform all the design and safety studies, the specific neutron and photon calculation tools, HORUS3D/N&P, dedicated to JHR simulation, were developed. This development follows the Verification & Validation-Uncertainty Quantification process; within this framework, the validation step aims at quantifying all the biases and associated uncertainties of the HORUS3D/N&P calculations. These biases originate from both the nuclear data and the calculation scheme, for JHR calculations at beginning of life or during depletion (in particular for the JHR core at equilibrium). This paper focuses on the quantification of the biases due to nuclear data and the associated uncertainties. A new experimental program, named AMMON, was conducted between 2010 and 2013 to provide experimental data for this quantification. A large part of the measurements has been analyzed using the Monte Carlo TRIPOLI-4 code and the JEFF3.1.1 and EPDL97 data libraries relative to neutron/photon transport and photon emission. The calculation biases, that rely on the discrepancies between Calculation and Experiment during the AMMON analysis, were transposed from AMMON to JHR. The synthesis of the present analysis is very satisfactory. The calculation biases remain limited. In addition, thanks to a very good control of the experimental uncertainties during measurements, it is shown that the a priori uncertainties due to nuclear data for parameters at JHR's beginning of life were reduced up to a factor of 2.