Discussion of nuking the well shut begins at the 2:00 minute mark.
The additional development that Matt Simmons uses to bolster his argument was the discovery by the US Navy of a second pipe inside the Blowout Preventer that shouldn’t be there. He speculates that it’s a piece of the well casing that was thrust upwards from the tremendous force of the initial explosion, from which he concludes that there’s not enough metal casing left for the relief well to attach to.
You gotta love the incredulous tone of voice and expression on the interviewer’s face at the end when Simmons tells her to forget about the relief well working, calling the whole idea “a sham.”