Objective THE DECONTAMINATION FOR DECOMMISSIONING PURPOSES HAS NOT YET BEEN APPLIED EXTENSIVELY FOR THE TOTAL CLEANING OF LARGE COMPONENTS. IN THE FRAME OF HEAT-EXCHANGER DECONTAMINATION, ONLY SOFT CHEMICALS HAVE BEEN APPLIED ON LARGE SCALE, AND UNRESTRICTED RELEASE LEVELS HAVE NEVER BEEN OBTAINED. MANY PROBLEMS ARE CONNECTED WITH TUBE BUNDLES WHICH HAVE VERY LARGE SURFACES AND WHICH ARE CONTAMINATED BOTH INSIDE AND OUTSIDE. THE SCOPE OF THE PRESENT WORK IS TO DEMONSTRATE THE FEASIBILITY OF DISMANTLING AND DECONTAMINATION OF A LARGE COMPONENT CMING FROM A FIRST GENERATION BWR (GARIGLIANO). EXPERIENCE GAINED IN OTHER PLANTS WILL BE TAKEN INTO ACCOUNT, IN THE SENSE THAT THE DECONTAMINATION OF THE SHELL, AND PROBABLY OF THE TUBE-SHEET, MAY BE CARRIED OUT BY ELECTROCHEMICAL WAY. THIS STUDY WILL BE MAINLY FOCUSED ON THE DECONTAMINATION OF TUBE BUNDLES. MOREOVER, THE ESTIMATION OF THE AMOUNT AND THE COMPOSITION OF SECONDARY WASTES PRODUCED IS AN AIM OF THE WORK. FINALLY, THE IMPORTANCE OF DECONTAMINATION TECHNIQUES IN DECOMMISSIONING AND, IN PARTICULAR, FOR THE UNRESTRICTED RELEASE OF TURBINE HOUSE BUILDING PARTS, OF SYSTEMS AND COMPONENTS, WILL BE EVALUATED. THE STUDY WILL RESULT IN THE ASSESSMENT AND QUALIFICATION OF AN EFFECTIVE AND ECONOMIC TECHNIQUE FOR THE DECONTAMINATION OF LARGE AND COMPLEX COMPONENTS WITH A PRODUCTION OF SECONDARY WASTES IN LIMITED QUANTITIES. Decontamination is commonly used in decommissioning plants in order to reduce radiation exposure (particularly to reduce human exposure levels) and to reduce the environmental release of materials. In this latter area, decontaminating tube bundles is a special case because they have large contaminated surface areas and relatively low weights. An innovative decontamination technique using corrosive chemicals, together with ultrasound, in a tank, was developed and was assessed in scale models. The performance of the new technique under realistic conditions was carried out in 10 full scale demonstration tests. The demonstration programme showed that the new decontamination process was able to reduce the level of radiation in the tubes of the tube bundle to lower than 0.3 Bq/g.1. PRELIMINARY EVALUATION OF THE CHARACTERISTICS OF THE SELECTED FEEDHEATER, INCLUDING OPERATING DATA, WITH RESPECT TO WATER CHEMISTRY AND RADIOACTIVITY INVENTORY. 2. DETERMINATION OF THE RADIOACTIVITY INVENTORY OF THE FEEDHEATER INCLUDING MEASUREMENTS ON SCRAP SAMPLES. 3. LABORATORY INVESTIGATIONS ON THE ULTRASONIC AND CHEMICAL PROCEDURES ON REPRESENTATIVE SAMPLES, INCLUDING TESTS ON A APPROPRIATE TREATMENT OF THE SPENT DECONTAMINANT. 4. DEFINITION AND SELECTION OF THE MOST SUITABLE PROCEDURE FOR THE DETERMINATION OF THE RESIDUAL ACTIVITY INVENTORY. 5. DESIGN AND CONSTRUCTION OF AN APPROPRIATE DECONTAMINATION FACILITY. 6. DISMANTLING AND DECONTAMINATION OF THE FEEDHEATER, TREATMENT OF THE SPENT DECONTAMINANT, CONDITIONING OF THE SECONDARY WASTES AND DETERMINATION OF THE RESIDUAL ACTIVITY INVENTORY. 7.EVALUATION OF OBTAINED RESULTS AND FINAL ASSESSMENT FOR POTENTIAL APPLICATION TO COMPONENTS OF FULL-SIZE BWR PLANTS. Fields of science natural sciencesphysical sciencesacousticsultrasound Programme(s) FP1-DECOM 2C - Research programme (Euratom) concerning the decommissioning of nuclear installations, 1984-1988 Topic(s) Data not available Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator Ente Nazionale per l'Energia Elettrica SpA (ENEL) EU contribution No data Address Via Monfalcone 15 20132 Milano Italy See on map Total cost No data
