Chapter 9 – Radiological Characterisation

Publisher Summary This chapter discusses the characterization of redundant nuclear facilities at the beginning of a decommissioning project and at intermediate stages up to the point where a building is being prepared for demolition. Characterization is an essential step at the beginning of the decommissioning process and may need to be repeated at different stages during the decommissioning. The results will be used to plan the methods used to dismantle the facility and manage the radioactive waste. It is also needed to determine the hazards to which workers and the general public will be exposed. It is important to have access to historical records. The characterization needs to be carefully defined and executed, particularly with regard to choice of methods, instruments, and sampling procedures. The methods used and the results obtained must be well documented. The first step in carrying out a radiological characterization is to review the existing historical information. The first step in carrying out a radiological characterization is to review the existing historical information. This will involve a search of health physics records and other records that will give an indication of the facility's operational history, such as the building maintenance records. "As-built" drawings and information on the structural condition of the facility are valuable. It is particularly important to find any references to incidents during the life of the facility that may have led to the spread of contamination. The most recent occupants of the facility prior to shut-down may be unaware of things that happened 20–30 years ago. It is a good idea to identify and debrief some of the personnel (often retired) who were associated with the early history of the facility.