the Iranians are looking for trade and security guarantees, as well as access to peaceful nuclear technology.
If the Iranians are serious, they'll abandon all nuclear efforts, including the "peaceful".
This is a Clinton-like scenario. Iran will play the nice guy for about twelve to eighteen months...and then, when a real independent nuclear inspection team shows up...there are signs they simply hid their entire program. The EU wants to send a team to question this...but Iran won't allow them. The UN then makes a big huffy statement...and then Iran says...well, you can come but we really don't want to discuss the matter. By this point, Iran will have over 100 nuclear bombs, and the EU will sit there and debate about how to settle this without military action. Iran will suggest a settlement of $100 million per bomb as adequate, and the EU will actually think about it...of course, this means a Iran Nuke tax on each European...but wouldn't that be so much better than a war? So they will pay them off, and get a promise that Iran won't make anymore. Eighteen months pass...and suddenly some Iranian nuclear scientist shows up in the UK, claiming of 300 more nuclear weapons. Oh my...Iran lied again? Oh my. The name of this whole thing should be "a cast of fools".