Five architects and two others passed on when a rocket motor detonated at a test extend on the White Sea on 8 August.
Protection specialists think it was a piece of an atomic controlled voyage rocket.
“We will surely be culminating this weapon paying little respect to anything,” Mr Putin told widows of the people in question.
What was Russia trying?
Surgeons dread atomic impact pollution
The ownership of “such one of a kind innovations”, he included, was “in itself… a generally huge and solid assurance for tranquility on the planet”.
The Russian head was talking on Thursday at a function at the Kremlin to display after death grants to the dead men’s families.
He didn’t determine what weapon had been included, saying just that the “specialized thoughts and arrangements” engaged with the undertaking were “without an equal on the planet”.