Physics and safety studies of a compact ADS design loaded with nitride fuel

We have performed transient analysis of a nitride fueled and heavy liquid metal cooled accelerator driven system, in which the pitch-to-diameter ratio of pin lattice was set at 1.26. Unprotected loss-of-flow, unprotected transient-over-power and protected loss-of-heat-sink transients were simulated in a geometrical model of the suggested ADS design, using safety parameters obtained with the MCNP/MCNPX code.The simulations indicated that the suggested ADS design could survive the full set of transients, thanks to the introduction of the austenitic 15/15Ti stainless steel as fuel cladding material.Thus, the viability of an ADS design with small pin pitch and concomitant high proton source efficiency could be confirmed.

► The suggested ADS design was modelled into the SAS4A/SASSYS code.
► Safety parameters of the suggested ADS were compared with those of the reference EFIT-400 design.
► The suggested design was confirmed to survive the postulated transients.
► Switching to the D9 stainless steel as cladding material was encouraged.