03.12.2012 15:48

Posiva to launch extensive testing in ONKALO

In the next few years, Posiva will carry out a series of tests in the underground research facility ONKALO to ensure adequate competence for all the phases of final disposal of nuclear materials. The activities include tests that have never been carried out in Finland in full scale.

What kind of tests will Posiva be performing in ONKALO over the next few years, research manager Kimmo Kemppainen?

"The tests include drilling the disposal holes, installing the disposal canister, installing the bentonite buffer around the canister, filling the disposal holes, and filling and plugging the deposition tunnel. At the same time, we will be developing and testing new procedures and techniques as well as the machinery required in the disposal activities."

Kimmo Kemppainen

Will all the tests be carried out in actual conditions?

"Preliminary tests will be performed on machinery above ground, but practically all testing will take place in tunnel conditions approximately 400 metres below the ground surface. Major testing of new methods can be challenging when carried out in narrow tunnels using special equipment, but we are used to working in the conditions prevailing in ONKALO.

How exceptional will these tests be?

"These tests have never been carried out in Finland before in full scale. In the next few years, Posiva's largest project to test the technical execution of final disposal is called the DOPAS-POPLU. Within the project, we will design and construct a deposition tunnel plug.

What kind of testing cooperation does Posiva engage in?

"Some of the tests will be carried out as EU projects, and others are led by Posiva. For example, the full-scale testing programme, the Lucoex, will include testing in Sweden, France and Switzerland. Planning and design work related to the testing operations will also be done by several specialised engineering offices.

Methods, machines and structures will be planned and designed together with partners in Finland and in other countries. Similar testing has been carried out in other countries, and we mean to learn from their experiences."

What is the objective of the extensive testing?

"We will get certainty of being able to carry out all the phases of disposal correctly. The tests will show how the theoretical planning and engineering and the reference solutions from other countries work in real conditions.

We will first prepare the submission of an operating licence application for the repository and then get ready to launch the final disposal of spent nuclear fuel."

How will the testing programme proceed?

"Some of the tests will begin next year, others later. Next year, the testing will be the most extensive it's ever been in the history of Posiva.

The tests I mentioned earlier only concern individual phases of the work. We aim at being able to carry out a full-scale filling test in ONKALO after the partial tests have been completed. In the full-scale test, one underground tunnel will be filled exactly as if used for final disposal – but without the spent nuclear fuel. We will also be able to carry out measurement and research work during the test.

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