"Nuclear weapons" covers a very wide range of power, you realize. Even today the world's arsenals include nuclear bombs ranging from a few kilotons to the 50 megaton Tsar Bomba, which although it never entered service, was tested at fifty megatons, and could have reached twice that if the Soviets had cared to risk the fallout that such an explosion would have caused, which as it turns out they didn't. (They replaced U-238 tampers in the bomb with lead, eliminating the tertiary fission stage and making it a nearly pure fusion bomb.) Saying "comparable to nuclear weapons" therefore doesn't mean a whole lot, especially considering we could likely do better than the Tsar Bomba if we felt the need to; it's just that so large a weapon has no practical use.