**3. Experiments**

Experiments were not placed in specific assembly locations in the core. This is unlike many light water test reactors which have specific ports or testing locations. Instead, experiments were often placed in the same hexagonal duct as a typical driver fuel assembly. This meant multiple experiments could be placed in the same assembly, experiments could be intermixed with fuel pins, or experiments could be placed in an assembly with dummy stainless-steel pins. The placement of an experiment in the core was largely determined by the conditions required for the experiments. If an experiment needed a large flux of high energy neutrons in a short period of time, it could be placed in the center of the core. On the other hand, if an experiment needed to experience a large neutron fluence over a long period of time, it could be placed in the periphery of the core. Overall, an experiment could likely be placed in any assembly position within the core, with the exception of the control/safety assemblies. To compensate for any loss of reactivity due to adding experimental assemblies, additional driver assemblies were placed in the periphery of the core.

EBR-II also examined multiple endurance type testing for both fuel and cladding [7]. In the 1970's, a series of experiments examined running fuels to cladding breach (RTCB) and running fuel beyond cladding breach (RBCB). These experiments

## *Experimental Breeder Reactor II DOI: http://dx.doi.org/10.5772/intechopen.105800*

were used to help increase the burnup capabilities for fuels and determine neutron fluence limits for these fuels. To accomplish this, an additional cover-gas cleanup system (GGCS) was installed to help remove radioisotopes that leaked from the fuel and into the argon cover gas.
