Not fission, the article is actually talking about "lattice confinement fusion" (aka "cold fusion".
From the article abstract:
" Here we postulate that the generation of heat is the result of three-body nuclear fusion of deuterons confined in hexagonal FeDx core-centre crystals; the reaction rate is enhanced by the combined attraction effects of high-pressure (~364 GPa) and high-temperature (~5700 K) and by the physical catalysis of neutral pions: 2D + 2D + 2D → 21H + 4He + 2 + 20.85 MeV.
Fission.. Fusion.... what’s a vowel here or there?......................