Safety analysis of the DONES primary heat removal system

• Published in: Fusion engineering and design 2020-12, Vol.161, p.112002, Article 112002
• Main Authors: Arena, Pietro, Di Maio, Pietro Alessandro, Nitti, Francesco Saverio
• Format: Article
• Language: English
• Subjects: Deuterium; DONES; Failure analysis; Failure modes; Irradiation; Lithium; Lithium loop; MELCOR; Neutron flux; Neutrons; Nuclear engineering; Nuclear fusion; Nuclear safety; PHRS; Relap5-3D; Safety analysis; Working fluids
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2020.112002

•The thermal-hydraulic behaviour of the DONES primary heat removal system has been studied using the RELAP5-3D code.•A parametric study was performed to assess the influence of the pump trip and beam shut-down delay on loop performances.•Results highlighted that the loop can work safely if the beam shut-down system works properly.•Results obtained are in line with those carried out adopting a different system code (MELCOR). The development of a neutron source able to reproduce the irradiation conditions typical of a nuclear fusion reactor, in order to test candidate structural materials, is the main goal of the Work Package Early Neutron Source (WPENS) of the EUROfusion action. This source, named Demo Oriented NEutron Source (DONES), is a facility where neutrons are produced by means of D-Li interactions. More in detail, a beam of 125 mA deuterium ions at the energy of 40 MeV strikes a lithium jet flowing in a purposely shaped channel in order to obtain an intense and stable neutron flux for the irradiation of material samples. In the framework of these activities, safety analyses are a key aspect in the DONES design and development. Among the postulated initiating events identified during the preliminary Failure Mode Analysis, the Loss of Flow Accident (LOFA) in the Primary Heat Removal System of the lithium loop, due to a trip of the electro-magnetic pump, is one of the most severe. In fact, the loss of lithium flow, combined with the failed stop of the accelerator, could lead to the destruction of the lithium flow channel in correspondence of the component named Back-Plate. For this reason, it has been chosen to investigate the LOFA adopting the deterministic system code RELAP5-3D. Results, obtained from this analysis, are critically discussed and compared with those obtained by a similar calculation carried out with MELCOR 1.8.6 code, in order to assess the RELAP5-3D capability of describing systems adopting lithium as working fluid.