Le 29 novembre 1999, le Premier ministre Ivan Kostov et Gunter Verheugen, commissaire chargé de l'élargissement, ont signé un protocole d'accord qui comportait les engagements suivants: fermeture des unités 1 et 2 de la centrale nucléaire de Kozloduy au plus tard fin 2002 et accord sur la date de fermeture des unités 3 et 4 à cette même date (mais avant 2008 et 2010, respectivement).
On 29 November 1999, then Prime Minister Ivan Kostov and Gunter Verheugen, Commissioner for enlargement, signed a Memorandum of Understanding which made the following undertakings: units 1 and 2 of the Kozloduy nuclear power plant were to be closed by the end of 2002 and closure dates for units 3 and 4 were to be agreed by the same deadline (but before 2008 and 2010 respectively).