FOCUS ON EUROPE | FINLAND


Finland’s path to final disposal


NEI looks back at Posiva’s four-decade journey leading to an operating licence application and construction of the world’s first deep geological repository


POSIVA IS AN EXPERT ORGANISATION responsible for the final disposal of spent nuclear fuel of its owners in Finland. Posiva oversees R&D work regarding the final disposal of spent nuclear fuel, as well as the construction and operation of the encapsulation plant and disposal repository. Site investigations for hosting a deep geological


repository, known as the ‘final disposal facility’, were started in the 1980s by Teollisuuden Voima. In 1994 the Finnish Parliament passed a law preventing the export and import of spent nuclear fuel. Hence, the other nuclear power plant operator in Finland, Fortum, joined the final disposal project and a company dedicated for nuclear waste management, Posiva Oy, was established. The first objectives of the company were to prepare an


application for a political decision-in-principle (DiP) for geological final disposal of spent nuclear fuel and to find a suitable site for the final disposal facility. In Finland, licensing of a nuclear facility is done according


Below: Posiva’s steps


for fi nal disposal of spent nuclear fuel Source: Posiva Oy


1980


to the Nuclear Energy Act through a stepwise process beginning with a decision-in-principle, continuing with a construction licence and culminating in an operating licence after completion. The site to host the final disposal facility was selected in 1999, and the selection was approved by the municipality of Eurajoki. An application was made in 2000 for a DiP to construct the final disposal facility and an encapsulation plant at Olkiluoto, introducing a so called KBS-3 method


(see below) with crystalline host rock as the disposal concept. The DiP was made by the Finnish Government and ratified by the Parliament in 2001. The DiP included a requirement that the preliminary site


investigations made above ground should be confirmed by site investigations at the actual disposal depth. Therefore ONKALO®


, an underground research and rock


characterisation facility, was constructed in 2004–2012. ONKALO®


has been constructed under the supervision of


the Nuclear Safety Authority (STUK), because from the early planning phase it has been designed to become a part of the final disposal facility for spent fuel. The site confirmation studies were continued until the disposal level — 420-430m below sea level — was reached in 2010. By constructing ONKALO®


, rock construction methods,


including a drill-and-blast excavation method and grouting of groundwater flows, were developed especially for the final disposal facility to avoid damage of the bedrock and unnecessary disturbance of the groundwater conditions. Also, a specific rock suitability classification method (RSC), was developed and tested iteratively during the construction work to assess rock suitability and to provide input information for design of the final disposal facility. A unique technology called Posiva Flow Log for locating


fractures and measuring groundwater flows in those was developed and has now been used for over 20 years not only in Olkiluoto, but by several other countries and industries.


1990


SITE INVESTIGATIONS, SELECTION OF THE SITE AND THE CONCEPT


2000


Construction of ONKALO®


2010


Excavations of final disposal facility


DETAILED DESIGN OF THE CONCEPT AND FACILITIES


2020


Construction of encapsulation plant


FINAL DISPOSAL FACILITY AND


ENCAPSULATION PLANT EKA-project


Government decision on total schedule


Government decision-in-principle


Construction licence


Application for operating licence


Operating licence


30 | March 2022 | www.neimagazine.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45