In view of the possible licensing needs of Small Modular Reactors (SMRs), due to the envisaged shortterm
deployment, the international scientific community has focused his interest in characterizing the SA
integral codes capabilities in simulating SMR behavior during postulated Design Basis Accident (DBA),
Beyond Design Basis Accident (BDBA) and Severe Accident (SA) scenarios. One type of SMR is the
integral Pressurised Water Reactor (iPWR), which is ready to be licensed as a new build because they start
from the well-proven and established large-LWR technology including moderate evolutionary design
modifications to increase the inherent safety of the plant. However, despite the inherent increase of the
safety of the plant with the adoption e.g. of passive safety systems and integral configuration, a sound
demonstration of iPWR ability to address SA should be carried out along a safety review process.
Therefore, in order to speed-up iPWR European licensing process, the Horizon Euratom project “Safety
Analysis of SMR with Passive Mitigation strategies – Severe Accident” (SASPAM – SA), coordinated by
ENEA (Italy), investigates the applicability and transfers of the operating large LWR knowledge and
know-how to iPWRs in view of SA and Emergency Planning Zone (EPZ) European licensing analyses
needs. In this framework, a code-to-code benchmark exercise between MELCOR and ASTEC integral
codes has been conducted by ENEA, considering a generic 300 MWe iPWR. Due to the integral
configuration a SBLOCA event has been considered; in particular a guillotine break of one Direct Vessel
Injection (DVI) line has been selected as Postulated Initiating Event (PIE) of the DBA sequence. The main
goal of the work is to evaluate the capability of the codes in simulating the dominant thermal-hydraulic
phenomena in a generic iPWR design and assess the possible encountered discrepancies.

This work has been published in the conference proceedings: Proceedings of the 11th European Review Meeting on Severe Accidents Research (ERMSAR2024).
DOI: https://doi.org/10.5445/IR/1000174165