Effect of operating pressure on the performance of a hybrid system of small modular boiling water reactor with external superheaters

•Conceptual design of hybrid Small Modular Boiling Water Reactor (SMBWR) with external superheaters is proposed.•Superheater can allow load-following and improve the thermal efficiency of SMBWR.•Operating SMBWR at higher pressure (up to 10.0 MPa) has no significant neutronic effects.•A load following capability (down to 65%) is demonstrated for the hybrid system.•Variable demand can be met by the hybrid system with the reactor operating at full capacity.