4. Work Management

The purpose of work management in controlled areas is to avoid unnecessary exposure and contamination of radiation workers.

As many jobs at NPPs are repetitive or similar in their contents, it is important to make use of a learning effect by taking certain steps in the PDCA cycle: Plan, Do, Check, and Act

1. Study of Work Methods

Radiation exposure occurs because of:

1. The presence of radiation sources (i.e. an environmental condition);

2. The need to perform tasks (e.g. maintenance tasks); and

3. The need for persons to access an area.

If one of these factors can be eliminated or

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And, measures against contamination, such as prevention of the spread of contamination by partitioning working places and/or installing ventilation facilities, decontamination methods, anti-contamination equipment for workers and contamination monitoring methods are studied and incorporated in the plan.

2. Approval of Radiation Work

The work plan is developed by the section in charge of the work in consultation with the radiation control section and with advice from the operation and safety sections, as appropriate. For the start of the work, approval of radiation safety as well as a work permit concerning facility safety and general safety must be obtained.

Work schedule

Work procedures

(preparation, implementation, and clean-up)

Safety measures

Rationalization of number of persons Qualitative factors

Level of skill

Experiences at works

.Human relations

Amount of projected lines

Education and training

Figure 6.6.1 Elements of exposure during work

individual tasks in controlled areas, the working environment must be well known, means of radiation reduction must be studied, the work schedule must be prepared, detailed work steps and the manpower plan must be adjusted, and the planned individual and group doses must be estimated. Then, the work plan must be developed reflecting past data to the above results.

Various tasks (more than a hundred) are performed during a plant periodic inspection. Exposure reduction measures are taken on a priority basis, as shown in Table 6.6.1, focusing on the tasks expected to result in higher doses and then on the work step with the highest dose in each task. Moreover, a careful study for ALARA is performed using a check sheet (Table 6.6.2).

Procedures for ensuring radiation safety are incorporated into the integrated safety rules known as the work permit system to safeguard the integrity of facilities (property) and to protect human life. This includes combining them with the procedures for preventing industrial accidents, such as electric shock, burns, oxygen deficiency, and falls to ensure comprehensive safety.

'*^{2 :} As most of the total dose of a power plant was due to the work done during periodical inspections, exposure reduction efforts were once focused only on measures for periodical inspection work. But nowadays, as the total doses have markedly decreased compared with those of the 1980s, it is important to take long-term measures focused on reduction of radiation sources, in addition to the measures for exposure reduction centering on workers during work activities.

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