Implementation of stage-3 decommissioning of the Triton Facility

Full text: An extensive decommissioning program has been launched by the French Atomic Energy Commission (CEA), including decommissioning of nuclear facilities related to the front-end and the back-end of the nuclear fuel cycle, and experimental reactors. This program includes the stage-3 decommissioning of the Triton facility, comprising two piles, Triton and Nereide, and a hot cell, located at the Fontenay-aux-Roses research centre. This facility was built in the late 1950s, primarily for R and D activities related to neutron physics studies, and radiological shielding experiments. As of 1982, stage-2 decommissioning started, was achieved in 1986 and since that date, no work has been done in the facility. This paper describes the extensive studies carried out to acquire a better knowledge of the facility radiological status, in order to set up dismantling scenarios and to reduce generated radioactive waste quantities. An overview of the selected dismantling scenario is provided, followed by the conclusions of the safety assessment studies, taking into account a number of significant non-radiological hazards. The paper also describes the preliminary dismantling operations performed in 2002 on concrete structures and decontamination of the hot cell walls. Significant experience feedback drawn up from these works is provided. Finally, is presented the ongoing work to be performed in the next eighteen months, until the final dismantling and decommissioning of Triton facility