THE PILOT VITRIFICATION FACILITY PIVER AT MARCOULES HAS BEEN OPERATED BETWEEN 1969 AND 1980, FIRST IN A DISCONTINUED PROCEDURE FOR THE VITRIFICATION OF WASTE ARISING FROM THE REPROCESSING OF GRAPHITE-GAS REACTOR FUEL ELEMENTS AND THEN FOR THE DEVELOPMENT OF A CONTINUOUS PROCEDURE FOR THE TREATMENT OF WASTE FROM REPROCESSING OF FAST BREEDER REACTOR (FBR) FUEL. IT IS PLANNED TO REUSE THE EXISTING CELL FOR A CONTINUOUS VITRIFICATION PROCEDURE OF WASTE GENERATED BY THE REPROCESSING OF FBR FUEL (PIVER 2).
THE OBJECTIVE OF THE PRESENT WORK CONSISTS IN A MULTI-STAGE DECONTAMINATION AND CLEANING OF THE HIGHLY CONTAMINATED CELL AND ITS EQUIPMENT, FOLLOWED BY REMOTE DISMANTLING OF THE INTERNALS, WITH SUBSEQUENT WASTE CONDITIONING AND TREATMENT ON THE SITE.
THIS TASK IS TO BE EXECUTED IN AN R&D SPIRIT, THE TARGET BEING THE PREPARATION OF A CONCLUSIVE ASSESSMENT ON ALL IMPORTANT TECHNICAL AND ECONOMIC ASPECTS OF THE WHOLE OPERATION.
A SUPPLEMENTARY AGREEMENT CONCLUDED IN 1988 PROVIDES AN EXTENSION OF THE WORK PROGRAMME.
The PIVER prototype vitrification facility was targeted for dismantling. Most of the work involved the vitrification cell containing the process equipment, which had to be cleared out and thoroughly decontaminated. This implied disassembling, cutting up, conditioning and removing all the equipment installed in the cell. Remote manipulation, handling and cutting devices were used and some prior modifications were implemented in the cell environment. The dismantling procedures were conducted under a detailed programme defining the process for each operation.
After equipment items and active zones were identified, the waste materials were removed, and several liquid decontamination operations were implemented. Removed activity, levels of irradiation in the cell and doses integrated by personnel were monitored to control progress and to adapt procedures to the conditions encountered.
B.1.-PRELIMINARY WORK CONSISTING IN THE MEASUREMENT OF THE INITIAL RADIOACTIVITY LEVELS; FEASIBILITY STUDIES FOR THE APPLICATION OF APPROPRIATE TECHNIQUES, PREPARATION OF DOSSIERS FOR REQUESTS OF AUTHORISATIONS FOR THE DISMANTLING AND THE TRANSPORT OF WASTES.
B.2.-CLEANING AND PRE-DECONTAMINATION OF THE CELL AND MAPPING OF THE REMAINING RADIOACTIVITY DISTRIBUTION..
B.3.-INTRODUCTION OF SUPPLEMENTARY TELEMANIPULATORS AND OF VARIOUS DISMANTLING TOOLS INTO THE CELL.
B.4.-DISMOUNTING CONDITIONING AND REMOVAL OF THE HEAVY CONCRETE SHIELDED INDUCTION COILS OF THE VITRIFICATION AND RUTHENIUM FILTER FURNACES.
B.5.-DISMANTLING CONDITIONING AND REMOVAL OF PIPE WORK AND OTHER EQUIPMENT, FOLLOWED BY HIGH-PRESSURE WASHING OF THE CELL AND MAPPING OF THE RESIDUAL RADIOACTIVITY DISTRIBUTION. THE SUPPLEMENTARY WORK PROGRAMME CONCERNS THE DESIGN, TESTING AND APPLICATION OF A PLASMA-ARC TORCH WITH SIMPLIFIED AND ROBUST CONTROL FOR IN-CELL DISMANTLING OF LARGE COMPONENTS.
B.6.-EXECUTION OF A LIMITED AMOUNT OF DIRECT INTERVENTIONS IN THE CELL FOR FURTHER DISMANTLING AND DECONTAMINATION (IN CASE OF ACCEPTABLE DECREASE OF THE RADIATION LEVEL).
B.7.-CONCLUSIVE ASSESSMENT OF THE WHOLE OPERATION OF DECONTAMINATION AND DISMANTLING OF THE PIVER 1 PLANT, INCLUDING APPLIED TECHNOLOGIES, ECONOMIC ASPECTS (COSTS, MAN-POWER) AND A BALANCE OF THE GENERATED RADIOACTIVE WASTE.