Dismantling and decontamination of the tube bundle of a feedwater preheater of the Garigliano BWR
The report deals with dismantling and decontamination of the tube bundle of a feedwater preheater of the Garigliano BWR nuclear plant. Decontamination is a common practice in decommissioning works and it can be used both for reducing radiation exposures and for the unrestricted release of materials. Decontamination of tube bundles is of particular importance because of their large contaminated surfaces and relatively low weight. At present no decontamination technique is available which can decontaminate components up to the level where unrestricted release of materials of tube bundles could be allowed. An innovative decontamination technique using aggressive chemicals, together with ultrasound in a tank, was developed by several laboratories and assessed by in-scale testing. A decontamination procedure involving two phases was used: ultrasound applied in water at 60 C, and ultrasound applied in a solution of HF/HNO(3) acids at 60-70 C. The performance of the new technique under real conditions was demonstrated by performing ten full-scale tests, on an assembly of 100 straight tubes, 1 metre long.
Bibliographic Reference: EUR 13255 EN (1991) 69 pp., FS, ECU 7.50
ISBN: ISBN 92-826-0509-4
Record Number: 199110301 / Last updated on: 1994-12-02
Original language: en
Available languages: en