POSIVA Report 2017-2



Safety Case Plan for the Operating Licence Application


Posiva Oy



Page count:



ISBN 978-951-652-266-4


The present report describes the plan to produce Posiva Oy’s safety case in support of the operating licence application for a facility for the geological disposal of radioactive waste at the Olkiluoto site. In the present context, a safety case is a synthesis of evidence, analyses and arguments that quantify and substantiate the level of expert confidence in the long-term safety of the facility. The plan is based on the lessons learned from the previous safety case (TURVA-2012) supporting the construction licence application, feedback from the Radiation and Nuclear Safety Authority (STUK), present regulations and regulatory guides and international guidance on post-closure safety assessment.

The disposal facility includes a spent nuclear fuel (SNF) repository and a repository for the disposal of low and intermediate level waste (LILW) from the operation and decommissioning of the encapsulation plant. The SNF repository design used in the present safety case is KBS-3V, in which the SNF canisters are emplaced in vertical deposition holes surrounded by bentonite buffer. The LILW repository, located at intermediate depth, is based on a system of engineered barriers (concrete and crushed rock) plus the natural barrier (host rock). 

The safety case consists of a portfolio of eight main reports, complemented by a number of supporting reports. The main reports in the portfolio are: Design Basis, Initial State, Low and Intermediate Level Waste Repository Assessment (LILW-RA), Performance Assessment and Formulation of Scenarios (PAFOS), Analysis of Releases, Models and Data, Complementary Considerations and Synthesis. The inclusion of the LILW-RA report in the safety case portfolio reflects the aim of integrating both the LILW repository and the SNF repository within the safety case, in accordance with the feedback from STUK. The surface environment is part of the disposal system and its assessment is also integrated in the overall safety case, and accordingly included in the scope of the PAFOS, Analysis of Releases and Models and Data reports. The Analysis of Releases report will contain the analysis of radionuclide release scenarios derived from PAFOS and LILW-RA and an assessment of their radiological consequences. The Synthesis report brings together all lines of argument in support of Posiva’s understanding of the evolution of the disposal system and long-term safety, evaluation of compliance with the regulatory requirements, and presents an overall statement of confidence in the long-term safety of geologic disposal of spent nuclear fuel at the Olkiluoto site.

The focus of the present plan is on the overall safety case methodology, the safety case portfolio structure, its most important features and main supporting activities, such as the formulation of scenarios and uncertainty assessment. The report also presents quality management in the safety case work.


Safety case, geologic disposal, spent nuclear fuel, low and intermediate level waste, safety as-sessment, scenarios


Safety Case Plan for the Operating Licence Application (pdf) (3 MB)


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