In Material Test Reactors (MTRs) all types of complex irradiation experiments are being performed. Due to the fact that most of the European MTRs have a unique design, an irradiation experiment that will be performed in two reactors will in most cases have a different lay-out between the two reactors. This different lay-out of the experiment will cause that experimental uncertainties in the various reactors will be different. The way in which the experimental uncertainties are assessed in the various reactors may also differ. This makes that there are no shared standards for these measurements. Some End-Users making use of two MTRs will not have any guaranty that results can be consolidated. Providing benchmarking and recommendations as a best practice guide for measurement methods will increase the quality of MTRs offer to the benefit of End-Users.

In MTR+I3 the approach of the experimental uncertainties among the various reactors will be compared for one type of experiment (nuclear fuel ramp testing) and for an experimental parameter (nuclear heating). The ultimate stake is the production of standards, but the main activity within MTR+I3 is to come to a better understanding and comparison of the approaches used in the various reactors.