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Conference Article: Decommissioning of the AVR reactor, concept for the total dismantling

Marnet, C.; Wimmers, M. (AVR GmbH, Duesseldorf (Germany)); Birkhold, U. (ISE GmbH (Germany))

Abstract

After more than 21 years of operation, the 15 MWe AVR experimental nuclear power plant with pebble bed high temperature gas-cooled reactor was shout down in 1988. Safestore decommissioning began in 1994. In order to completely dismantle the plant, a concept for continued dismantling was developed according to which the plant could be dismantled in a step-wise procedure. After each step, there is the possibility to transform the plant into a new state of safe enclosure. The continued dismantling comprises three further steps following Safestore decommissioning:

  1. Dismantling the reactor vessels with internals.
  2. Dismantling the containment and the auxiliary units.
  3. Gauging the buildings to radiation limit, release from the validity range of the AtG (Nuclear Act), and demolition of the buildings.
For these steps, various technical procedures and concepts were developed, resulting in a reference concept in which the containment will essentially remain intact (in-situ concept). Over the top of the outer reactor vessel a disassembling area for remotely controlled tools will be erected that tightens on that vessel and can move down on the vessel according to the dismantling progress.

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key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Technical committee meeting on technologies for gas cooled reactor decommissioning, fuel storage and waste disposal. Juelich (Germany) 8-10 Sep 1997
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--1043, pp:17-39