Well, if you had no ambitions of developing nuclear weapons why not be upfront with this information and hand it over to the IAEA at once and not wait almost a decade before you more or less are forced to admitting having such a document?  

The NPT doesn't only prohibit purchasing equipment for nuclear weapons, but also refrain from what can be seen as seeking the assistance of others in developing such weapons:

Article II

Each non-nuclear-weapon State Party to the Treaty undertakes not to receive the transfer from any transferor whatsoever of nuclear weapons or other nuclear explosive devices or of control over such weapons or explosive devices directly, or indirectly; not to manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices; and not to seek or receive any assistance in the manufacture of nuclear weapons or other nuclear explosive devices.