Ein neuer Ansatz zur Bewertung der Wirksamkeit von Barrieren im Endlager. Hauptband und Kurzfassung. Technischer Anhang 1: Risikobezogene Bewertung begrenzter Freisetzungen. Technischer Anhang 2: Dokumentierte Erfahrung hinsichtlich dichter Dammbauwerke im Salinar. Technischer Anhang 3: Grundlagen der Bewertung von Hydroxylapatit als chemische Barriere gegenueber Schwermetallen Abschlussbericht

Multi-barrier systems are accepted as the basic approach for long term environmental safe isolation of radioactive waste in geological repositories. Assessing the performance of natural and engineered barriers is one of the major difficulties in producing evidence of environmental safety for any radioactive waste disposal facility, due to the enormous complexity of scenarios and uncertainties to be considered. This report outlines a new methodological approach originally developed basically for a repository in salt, but that can be transferred with minor modifications to any other host rock formation. The approach is based on the integration of following elements: (1) Implementation of a simple method and efficient criteria to assess and prove the tightness of geological and engineered barriers; (2) Using the method of Partial Safety Factors in order to assess barrier performance at certain reasonable level of confidence; (3) Integration of a diverse geochemical barrier in the near field of waste emplacement limiting systematically the radiological consequences from any radionuclide release in safety investigations and (4) Risk based approach for the assessment of radionuclide releases. Indicative calculations performed with extremely conservative assumptions allow to exclude any radiological health consequences from a HLW repository in salt to a reference person with a safety level of 99,9999% per year. (orig.)Published in 5 separate volumesSIGLEAvailable from TIB Hannover: F01B581+a: F01B582+a: F01B583+a: F01B584+a: F01B585+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman