IFMIF, the European-Japanese efforts under the Broader Approach Agreement towards a Li(d,xn) neutron source:current status and future options

摘要: Abstract The necessity of a neutron source for fusion materials research was identified already in the 70s. Though neutrons induced degradation present similarities on mechanistic approach, thresholds energies crucial transmutations are typically above fission spectrum. generation He via 56 Fe (n,α) 53 Cr future reactors with around 12 appm/dpa will lead to swelling and structural embrittlement. Existing sources, namely or spallation sources different degradation, attempts extrapolation unsuccessful given absence experimental observations operational ranges reactor. Neutrons broad peak at 14 MeV can be generated Li(d,xn) reactions; technological efforts that started FMIT early 80s have finally matured success IFMIF/EVEDA under Broader Approach Agreement. status today five challenges, perceived past as most critical, addressed. These are: 1. feasibility IFMIF accelerators, 2. long term stability lithium flow nominal conditions, 3. potential instabilities screen by 2 × 5 MW impacting deuteron beam, 4. uniformity temperature specimens during irradiation, 5. validity data provided small specimens. Other ideas material testing been considered, but they possibly either not technologically feasible if fixed targets considered would require results facility reliably designed. In addition, we know beyond reasonable doubt cost IFMIF, consistently estimated throughout decades, is marginal compared less ambitious DEMO reactor performance being correlates lower need flux; thus its two accelerators needed since only one accelerator European DONES Japanese A-FNS propose, needs > 10 dpa/fpy fulfilled. World roadmaps stipulate relevant middle next decade, phase materializing this four decades old dream.