Euratom Treaty
EU Treaty on nuclear co-operation between the original six members who established the EEC Treaty in 1957.
The EURATOM Treaty should have been attached to the EU Constitution as a protocol. According to the Lisbon Treaty it remained as a Treaty on its own.
Links
See Treaty establishing the European Atomic Energy Community (Non-official consolidated version), http://eur-lex.europa.eu/en/treaties/dat/12006A/12006A.html