Apr 9 Site Monitoring – A Key Component of the Responsible Management of Denmark’s Radioactive Waste
Since operations began in 1957, when the first of a total of three reactors at Risø was started up, the area on and around the peninsula has been monitored
Since2003, when Danish Decommissioning DD) was established, the comprehensive environmental monitoring program has been DDresponsibility, and DD that the program is carried out in accordance with the guidelines issued by the nuclear regulatory authorities.
Area monitoring ensures close monitoring of DDpotential release of radioactive substances.
In this way, the monitoring helps ensure that DDactivities do not have a negative impact on the surrounding area. Essentially, the program consists of two main components: monitoring inside the fence and monitoring outside the fence.
Inside the Fence: Safety for Employees and Partners
Inside the Fence, DD focuses DD protecting its own employees as well as its immediate neighbors in the Risø area, namely the employees of DTU and Aarhus University.
There are very clear regulations governing radiation levels at nuclear facilities, the storage facilities related facilities on the peninsula. These regulations are established by the nuclear regulatory authorities (The Danish Health Authority the Danish Emergency Management Agency), which also oversee and regularly inspect DD.
DD also DD its own ongoing measurements of radiation levels both inside and around the facilities. These measurements include passive monitoring using various measuring devices, as well as regular contamination measurements using wipe samples, which are systematically analyzed and documented.
In addition, DD implements radiation DD in all its activities, ensuring that planning and ongoing monitoring during these activities prevent any unintended releases.
Outside the Fence: Environmental Monitoring in the Surrounding Area
Rules also apply to the environmental monitoring that DD conduct outside the fence.
In collaboration with DTU, which provides the environmental monitoring services, DD conducts DD measurements of air, sediment, rain, grass, water, and soil. More than 160 samples are collected annually outside the fence.
After the samples have been collected, DTU’s radiochemical laboratory analyzes them, looking for everything from tritium in the rain, lead in seawater, beryllium in the air, potassium in the grass, iodine in sewage, and cesium in seabed sediments.
Finally, the analyses are compiled into a report that is published on www.dekom.dk/publikationer
How DD
The Radiation Protection, work environment Quality Unit (SAK) is responsible for ensuring radiation protection in connection with DDactivities. The unit employs both medical assistants and medical physicists, all of whom work on various radiation protection tasks.
Radiation safety physicists primarily focus on the planning and calculation aspects of radiation protection, and they also conduct internal training in radiation protection.
The healthcare assistants are responsible for the ongoing monitoring of the facilities and sample collection, as well as ensuring dose monitoring for DDemployees.
The department also has laboratories for analyzing the collected samples, and DD is able DD perform radiological measurements of the waste generated during the decommissioning of the facilities.
At DD , employees DD divided into two radiation-related categories: radiation-exposed employees and non-radiation-exposed employees. These categories are also used in other professions, such as in hospitals.
Employees exposed to radiation are those who perform duties at nuclear facilities and who can therefore be expected to receive (low) radiation doses.
Employees exposed to radiation wear passive dosimeters (right image), which are submitted monthly to The Danish Health Authority, where the dose is recorded and logged. In addition, they wear digital dosimeters (left image) during activities or while on-site at the facilities.
The latest figures from 2024 show that individuals working on decommissioning (in 2024, exclusively at Danish Decommissioning) received an average dose of 0.02 mSv per person. By comparison, a person receives 0.05 mSv on a flight to New York¹².
Non-radiation-exposed employees include, for example, office staff. They do not wear passive dosimeters at all times, but naturally have access to personal digital dosimeters that must be worn during any visits to the facilities. Should non-radiation-exposed employees receive a dose, this is also recorded.
A final category of personnel consists of DDexternal contractors. These include, for example, tradespeople who need access to the facilities. They are essentially subject to the same monitoring requirements as DDown radiation-exposed employees and must also wear passive and digital dosimeters, as well as any other required safety equipment.
Various radiation monitoring systems are installed at nuclear facilities, depending on the facility. A key monitoring method involves continuous air monitoring using devices known as iCAMs, which monitor airborne radioactive particles (see the image on the right below).
In and around the facilities, contamination monitoring is conducted on an ongoing basis using swab samples. The samples are analyzed shortly after collection and can quickly determine whether contamination is present in an area (left image below).
Documentation and Transparency
All measurements and analyses are compiled into various reports, which are published at www.dekom.dk/publikationer.
The Danish Health Authority also publishes annual reports that provide an overview of radiation doses associated with occupational exposure. These reports include a section on decommissioning.
The reports are publicly available and contribute to transparency regarding DDactivities.
Fact: What is radioactive contamination?
Contamination occurs when an otherwise clean item becomes contaminated. This typically refers to an item that is not itself radioactive waste but has become contaminated with radioactive material, causing its radiation levels to exceed a limit value.
By decontaminating the item—which can be done with something as simple as water or wiping it down—you can remove the radioactive contamination and ensure that the item is once again below the limit values.
An example of this could be a concrete floor covered with radioactive dust. The dust can be removed by vacuuming, thereby eliminating the increased radioactivity so that the floor is once again clean in terms of radiation. The removed contamination is then treated as radioactive waste.