Preliminary Assessment of Radiolysis for the Cooling Water System in the Rotating Target of SORGENTINA-RF

Abstract

The SORGENTINA-RF project aims at developing a 14 MeV fusion neutron source featuring an emission rate in the order of 5–7 × 1013 s−1. The plant relies on a metallic water-cooled rotating target and a deuterium (50%) and tritium (50%) ion beam. Beyond the main focus of medical radioisotope production, the source may represent a multi-purpose neutron facility by implementing a series of neutron-based techniques. Among the different engineering and technological issues to be addressed, the production of incondensable gases and corrosion product into the rotating target deserves a dedicated investigation. In this study, a preliminary analysis is carried out, considering the general layout of the target and the present choice of the target material.

A Study of Accelerated Corrosion of Stainless Steels under Highly Oxidizing Conditions

“…After being exposed to radiation, water undergoes a breakdown sequence, and in a mass of liquid, some chemically aggressive species form. Figure 1 shows a schematic representation of the processes occurring at different moments and the species that form when water molecules are subjected to radiolysis [12,13].…”

“…After being exposed to radiation, water undergoes a breakdown sequence, and in a mass of liquid, some chemically aggressive species form. Figure 1 shows a schematic representation of the processes occurring at different moments and the species that form when water molecules are subjected to radiolysis [12,13]. Many of the species formed during this process have very high electrochemical potential and are strong oxidants, much stronger than substances such as ozone or chlorine.…”

“…In such a case, even steel reactivity in regard to water can be very different from what is observed in more standard conditions, because of operating conditions in terms of temperature, pressure, and external parameters, and because of intrinsic physical phenomena, in particular, the water radiolysis. Very briefly, water radiolysis is the dissociation of water molecules due to radiation, directly in the case of ionizing radiation or indirectly in the case of high-energy neutron beams [12,13]. As a consequence of radiolysis, highly reactive species, such as radicals, free electrons, ions, and atomic oxygen form, and the pH of the system can be far from neutrality [13].…”

“…Figure 1. Chemical-physical reactions occurring during water radiolysis (inspired by references[12,13]). …”

Mechanical Behaviour of the Rotating Target SORGENTINA-RF

“…The general description of the project and the main activities can be found in further detail in [3] while a set of specific studies is presented in [4][5][6][7][8][9][10].…”