It is possible that this is a vaguely remembered description of The Reefs of Space, by Frederick Pohl and Jack Williamson. It was serialized in three parts in 1963 and published as a book in 1964. Two sequels followed, The Starchild and Rogue Star, marketed as The Starchild Trilogy, although the books really only share a common setting; there is no continuity of characters or plot between the three volumes.
In The Reefs of Space, the main character, Steve Ryeland, has been arrested at the beginning of the book and tortured for information by the secret police of the totalitarian empire known as The Plan of Man. After the torture, he is set to work on a top-secret project, to prepare mankind for the dangers of the recently discovered reefs of space, where strange creatures with strange powers exist. The existence and nature of the reefs and their inhabitants is a mystery, except that they are very dangerous; and it seems like everyone expects Ryeland to know more about the topic than he actually does.
In the course of being transported to the research site and during his time there, Ryeland meets and falls in love with the daughter of the Planner, the human leader of The Plan of Man (although the real leader is the merciless Planning Computer). Even though Ryeland is a "risk," with an explosive collar locked around his neck, so that he can be killed instantly if the computer ever things he has become a real danger, he and the planner's daughter fall in love. She convinces him that the project he is working on will be of real value to humankind.
Eventually, Ryeland actually travels to the reefs, and in a cave there he confronts a deadly pyropod, one of the most dangerous monsters that the reefs have to offer. That is not really the climax, although the end of the book is unfortunately rather rushed, and much of the exciting promise of the reefs is never realized.
The plot summary from Goodreads:
Far beyond the orbit of Pluto, half-mythical bodies circle the Solar System--the Reefs of Space, unknown, shrouded in mystery, the goal of human conquest, the obsession of the Plan of Man, tyrannical ruler of Earth. The Reefs of Space brings humanity to the brink of the stars. Steve Ryeland, enslaved by Earth's tyrannical Plan of Man computer, is given the world's most important job—to develop a "jetless drive," an extraordinary new space propulsion mechanism.
Yet the most important thing on Steve's mind was not his work, but the iron collar locked securely around his neck. Filled with a lethal charge of explosives, it could be detonated any time the Plan of Man considered him too much of a risk.
That's why he had to obey every order, and succeed at his experiments. Only then, perhaps, could he use the jetless drive himself… and escape to the safety of the half-mythical Reefs of Space, strange formations rumored to exist somewhere beyond the orbit of Pluto. But if he failed, the next step would be the Living Body Bank—a scientific horror chamber from which no one ever returned.