This sounds like John C. Wright's Golden Oecumene series.
The main character of the book finds out that he built an interstellar ship with the use of a collider and then removed his memory to refuse from interstellar travel. He also had a suit built with the use of a collider. Both could resist any heat, even inside of the Sun.
From this review
That man is Phaethon, an engineer and visionary who, as The Golden Age
begins, discovers that he has recently entered into an agreement to
wipe most of the last two hundred and fifty years of his life from his
memory. His attempts to find out why he agreed to have his memory
erased and whether he should seek to regain his memories form the
narrative structure of the story.
From the book itself:
The expense of this suit was staggering. The material was rare; only
the supercollider that orbited the equator of Jupiter could generate
sufficient energy to create the artificial atoms, and even that
required a major percentage of the output of the small star that
Gannis had made by igniting Jupiter. This suit had been constructed
one atom at a time. The black material, now inside the suit, was
cyclic nano-machinery, which would form a self-contained and
selfsustaining symbiosis with the wearer: a miniature and complete
ecosystem. But what in the world was it for? Swimming among the
granules of the sun? Walking into the core chambers of plasma
reactors?
I think the name of this book is the name of the ship, but I can't remember it.
The second book in the series is The Phoenix Exultant which is the name of Phaeton's ship.
