The risks of external exposure of personnel are linked to the treatment in the plant of products having a significant в, у and/or neutron activity. Radiation exposure of operations personnel or the public must be below the regulatory constraint and as low as reasonably achievable (ALARA). This is achieved by:

• provision of radiation shielding

• monitoring of radiation fields both within and around the plant

• monitoring of normal occupational exposure of staff

• limiting radiation exposure of staff by use of additional protective equipment and careful health physics monitoring for specific situations (maintenance or exceptional working conditions)

The accessible parts of the plant are categorized into different classes so that the working conditions may be adapted to the radiological conditions.

488 Nuclear fuel cycle science and engineering