USA almost build nuclear tank.Here:
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiOhvbyvvH7AhVQtIsKHV52DxcQFnoECBAQAQ&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FChrysler_TV-8&usg=AOvVaw2jOG7BqWq_BeAv5GbaVFPh
Pity,that it never get mass produced.One...