Abstract
A sensitivity analysis of the zone of influence (ZOI) was performed for high energy arcing fault (HEAF) scenarios in nuclear power plants (NPPs), following the analytical procedure in NUREG-2262. HEAF is characterized by arc-plasma formation within high voltage equipment, accompanied by metallic vapors, high temperature, and high pressure, and it can impose severe thermal damage on adjacent critical equipment. To quantify these effects, the fire dynamics simulator (FDS) was employed, and a systematic sensitivity analysis was conducted for grid resolution and major physical and geometric parameters. As the grid size increases, temperature and velocity gradients are under-resolved and the incident thermal exposure tends to be overpredicted. Over the mesh range of 0.04–0.10 m, the representative 300 MJ case showed a ZOI variation of about 0.19 m, corresponding to approximately 24%. Between arc energy and maximum heat release rate (HRR max ) that define the arc profile, changes in arc energy had a greater impact on the resulting ZOI. Most electrode and cabinet inputs, when varied by ±50%, produced ZOI changes within approximately ±10%; by contrast, when evaluated against the 15 MJ/m 2 ZOI threshold, sensitivity to arc energy ranged from −40% to +55%, maintaining an intact enclosure reduced the ZOI by up to approximately 40%. Accordingly, accurate specification of arc energy together with sufficient grid resolution was identified as essential for ensuring the reliability of HEAF modeling.