Numerical data and functional relationships in science and technology/ Group 8: Advanced materials and technologies. Vol. 4, Radiological protection / authors: D. Becker ... Ed.: A. Kaul ...

8 Decontamination...................................................................................................................................................................................................8-1 8.1 Decontamination of materials.....................................................................................................................................................................8-1 8.1.1 General approaches to decontamination ..........................................................................................................................................8-2 8.1.1.1 Contamination.............................................................................................................................................................................................................8-2 8.1.1.2 Characteristics of oxide layer in BWRs and PWRs ..............................................................................................................8-2 8.1.1.3 Other types of contamination......................................................................................................................................................................8-3 8.1.1.4 Decontamination ......................................................................................................................................................................................................8-4 8.1.1.5 The use of decontamination in decommissioning ...................................................................................................................8-4 8.1.1.6 Identification of decontaminable components...........................................................................................................................8-5 8.1.1.7 Effectiveness of decontamination, decontamination factor...........................................................................................8-6 8.1.1.8 Decontamination techniques (processes) ........................................................................................................................................8-7 8.1.1.9 Decontamination and secondary waste generation.................................................................................................................8-8 8.1.2 Decontamination techniques for large volume closed systems .................................................................................8-8 8.1.2.1 Reactor decontamination in BWRs and PWRs..........................................................................................................................8-8 8.1.2.2 Fuel assemblies and decontamination............................................................................................................................................. 8-12 8.1.2.3 Decontamination of sodium cooled systems............................................................................................................................ 8-12 8.1.2.3 Gas cooled reactors (WAGR)................................................................................................................................................................. 8-13 8.1.3 Decontamination techniques for segmented parts............................................................................................................... 8-13 8.1.3.1 Chemical decontamination......................................................................................................................................................................... 8-13 8.1.3.2 Electrochemical decontamination....................................................................................................................................................... 8-15 8.1.3.3 Jetting decontamination techniques.................................................................................................................................................. 8-18 8.1.3.4 Ultrasonic decontamination ...................................................................................................................................................................... 8-19 8.1.3.5 Decontamination by foams........................................................................................................................................................................ 8-21 8.1.3.6 Decontamination by gels.............................................................................................................................................................................. 8-21 8.1.3.7 Decontamination by pastes........................................................................................................................................................................ 8-21 8.1.3.8 Mechanical decontamination techniques..................................................................................................................................... 8-21 8.1.3.9 Decontamination by strippable coatings...................................................................................................................................... 8-22 8.1.3.10 Melting........................................................................................................................................................................................................................... 8-22 8.1.4 Decontamination techniques for building surfaces............................................................................................................ 8-22 8.2 Decontamination of skin .............................................................................................................................................................................. 8-24 8.2.1 Introduction............................................................................................................................................................................................................... 8-24 8.2.2 Transport of radioactive substances via the skin.................................................................................................................. 8-24 8.2.2.1 Anatomy of the skin.......................................................................................................................................................................................... 8-24 8.2.2.2 Transport procedure.......................................................................................................................................................................................... 8-25 8.2.3 Skin dose at contamination........................................................................................................................................................................ 8-25 8.2.3.1 Calculation of the equivalent dose to the skin......................................................................................................................... 8-25 8.2.3.2 Equivalent dose rate conversion coefficients.......................................................................................................................... 8-26 8.2.4 Decontamination measures........................................................................................................................................................................ 8-30 8.2.4.1 Organisational and preliminary measures .................................................................................................................................. 8-30 8.2.4.2 First aid measures of skin decontamination.............................................................................................................................. 8-30 8.2.4.3 Specific decontamination procedures ............................................................................................................................................. 8-31 8.2.4.4 Decontamination of specific body regions and organs .................................................................................................. 8-32 8.2.5 Procedure at residual contamination and fixing a reference value..................................................................... 8-32 8.2.5.1 Frequency of decontamination steps................................................................................................................................................ 8-32 8.2.5.2 Derivation of the reference value for residual contamination................................................................................. 8-32 8.3 References................................................................................................................................................................................................................... 8-34 9 Decorporation of radionuclides...........................................................................................................................................................9-1 9.1 Introduction...................................................................................................................................................................................................................9-2 9.2 General considerations.......................................................................................................................................................................................9-2 9.2.1 Factors affecting the efficacy of treatment....................................................................................................................................9-2 9.2.2 Factors influencing treatment decisions...........................................................................................................................................9-3 9.2.3 Decision levels ...........................................................................................................................................................................................................9-3