Abstract

Many hospitals generate waste that contains hazardous substances. This is known as specific hospital waste, or SHW. Examples of SHW are syringes or the urine of people who receive chemotherapy. This type of waste may not be disposed of in the conventional way, through incineration. Zavin, the medical waste processor, must follow a separate procedure for this. Zavin does not accept barrels that are radioactive. That is why large hospitals and Zavin both check for radioactivity in barrels containing SHW.

In spite of these checks, barrels containing too much radioactive material end up with Zavin on exceptionally rare occasions. When Zavin intercepts such a barrel, it asks RIVM to determine how radioactive the barrel’s contents are. Previously, there was no generally accepted process for this. On the instruction of the Authority for Nuclear Safety and Radiation Protection (Autoriteit Nucleaire Veiligheid en Stralingsbescherming, ANVS), RIVM has now developed such a process.

This makes it possible to measure radioactivity inside these barrels without the need to open them up. The reason why this matters is that people must not be exposed to hazardous biological material in SHW. An essential step in the process involves turning the barrel while the measurement is being taken. At the same time, the barrel must remain around 1 metre away from the measuring equipment. This is to ensure a sufficiently minor margin of error. When necessary, the barrel may be moved closer to the sensor, for example if the radioactivity level of the barrel’s contents is low. This does, however, increase the level of uncertainty somewhat.

RIVM tested the process described above by placing a source with a known radioactivity level inside a barrel. When the barrel was not turned, the detector did not return the correct radioactivity level. The correct radioactivity level could only be measured by turning the barrel. This is proof that the process works as desired and is suitable.