For explosion you want a chain reaction that consumes your entire piece of U-235.
https://robertfentongary.com/?p=12935
A rocket nozzle with 4 types of ultra-thin graphene tape fed into a vise-tamper would be a nuclear rocket.
Amor Fati (Love Your Fate)
Wind or Water Can Knock Down Your House — This One Goes Back Up Quick and Easy
This Book Describes My Patent and How to Use It.
Inventions by Robert Fenton Gary 