Fusion Engineering and Design 86 (2011) 2632–2634 Contents lists available at ScienceDirect Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes Compact tokamaks as convenient neutron sources for fusion reactors materials testing F. Bombarda a , B. Coppi b , Z.S. Hartwig b , M. Sassi a , M. Zucchetti b,c,∗ a ENEA, CR Frascati, Rome, Italy b Massachusetts Institute of Technology, MIT, Cambridge, MA, USA c Politecnico di Torino, Torino, Italy article info Article history: Available online 16 September 2011 Keywords: Neutron sources Materials testing Ignitor Radiation damage abstract Radiation damage evaluations have been performed with the ACAB code for fusion-relevant materials in an Ignitor-like compact fusion device that could be used as a neutron source for materials testing. Values ranging from 1.6 × 10 -26 to 2.4 × 10 -25 dpa per source neutron have been obtained, which translates into 16–250 dpa/y at full operating power and demonstrates the potential of this neutron-rich device for fusion materials testing. It will be shown that only a few full-power months of operation with a feasible operating duty cycle are sufficient to obtain relevant radiation damage values in terms of dpa. An estimate of the radiation damage on selected machine components will be presented, and solutions to solve the problem of radiation damage to the insulator of the toroidal field insulator will be discussed. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Fusion will require the development of radiation resistant materials, able to survive damage from neutrons with an energy spectrum peaked near 14 MeV and with annual doses in the range of 20 dpa (displacement per atoms), and total fluences of approxi- mately 200 dpa. The testing of candidate materials, therefore, requires a reliable high-flux source of high energy neutrons. DT fusion creates more neutrons per energy released than traditional neutron sources, such as fission or spallation, and may, in the near term, surpass either as the most intense neutron source. A tokamak neutron source could be designed and built in a relatively short time, by extrap- olating present designs of fusion tokamaks. Furthermore, compact high-field tokamaks may be the optimal configuration for a fusion neutron source due to their compact dimensions, high magnetic field, high neutron production, and flexibility of operation. This study presents the development of a tokamak neutron source for a material testing facility using an Ignitor-based concept. Ignitor is a proposed compact high magnetic field tokamak, aimed at reaching ignition in DT plasmas and at studying them for peri- ods of a few seconds. In order to act as a suitable neutron source for materials testing, Ignitor operating parameters have been revised, ∗ Corresponding author at: Politecnico di Torino, DENER, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. Tel.: +39 011 5644464. E-mail addresses: zucchett@mit.edu, massimo.zucchetti@polito.it (M. Zucchetti). as discussed below, to achieve a longer plasma discharge length, which produces neutron fluences that are shown to be appropriate for studying fusion-relevant radiation damage to materials. 2. Materials and methods We have assumed the neutron energy spectrum in the Ignitor first wall as reported in [1]. The total neutron flux on the first wall, computed per source neutron produced in the plasma, is 3.348 × 10 -5 n/cm 2 s [1]. At maximum performance, with DT 50/50 discharges, the neutron production in Ignitor is 3.33 × 10 19 n/s (see Fig. 1). To computer material damage, a recent, multi-group dpa cross section data base has been obtained by the NEA Data Bank [2]. It is an ENDF/B-VII Damage Library, processed with NJOY99.220 in 211 energy groups, with a VITAMIN-J+ structure. The values of the dpa have been obtained using the ACAB activation code [3]. An initial evaluation has been made for a target of pure iron located in the Ignitor first wall. The dpa rate, expressed in terms of displacements per atom per neutron produced in the plasma, is: D1 (Fe) = 3.22 × 10 -26 dpa/n (1) In a full power year of operation, this translates into a yearly dpa rate of: D2 (Fe) = 33.84 dpa/y (2) These data are consistent with evaluations found in literature for Iron in other fusion devices, like IFMIF, ITER, DEMO, etc. [4]. 0920-3796/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.fusengdes.2011.04.059