I.-In order to detect in good time any situation likely to impair the effectiveness of the preventive measures implemented, the employer shall:
1° Periodically, or if necessary continuously, carry out the necessary checks in the light of the results of those provided for in I of Article R. 4451-44 in the defined areas referred to in Article R. 4451-24;
2° In means of transport used for the transport of radioactive substances within or outside the establishment or, failing that, the company, periodic checks are carried out when the vehicle is empty, in order to ensure that there is no contamination of the means of transport and that the level of external exposure is similar to that of the ambient background noise.
II-These periodic checks are carried out by the radiation protection advisor.