The Generation IV Pebble Bed Modular Reactor (PBMR) is being considered as a promising concept to produce electricity or process heat with high efficiencies and unique safety features. The PBMR is a high-temperature, helium-cooled, graphite moderated reactor. The fuel elements consist of 6 cm diameter spherical graphite “pebbles” containing each thousands of uranium dioxide microspheres. As the...

This report documents the work completed on the X-PREX facility under NEUP Project 11-3172. This project seeks to demonstrate the viability of pebble fuel handling and reactivity control for fluoride salt-cooled high-temperature reactors (FHRs). The research results also improve the understanding of pebble motion in helium-cooled reactors, as well as the general, fundamental understanding of lo...

This paper describes an approach for developing threat models for attacks on control systems. These models are useful for analyzing the actions taken by an attacker who gains access to control system assets and for evaluating the effects of the attacker’s actions on the physical process being controlled. The paper proposes models for integrity attacks and denial-of-service (DoS) attacks, and ev...

At the ENEA TRIGA research reactor (Casaccia Research Center, Rome), a new neutron collimator has been designed and installed at the neutron tangential channel. This collimator, that is part of a neutron/X-ray facility for NDT analysis, was experimentally characterized and optimized in terms of thermal neutron flux, its spatial/energetic distribution, photon air KERMA and effective beam diamete...