Switzerland Takes Concrete Actions to Phase Out All Cesium-137 Blood Irradiators by 2025

Radioactive sources such as those used in medical, research and industrial applications offer important benefits to society. However, if stolen and used to build a “dirty bomb,” a radioactive source can have devastating effects to public health, the environment, the economy—and to cities, which can suffer long-term contamination.

The good news is that some high-activity sealed sources (HASS), particularly cesium-137 commonly used in medical and experimental irradiation, can be readily replaced by alternative technologies.

Unfortunately, very few governments have regulations or policies in place to phase out HASS—but the Government of Switzerland is one of the few, taking concrete regulatory actions to phase out cesium-137 blood irradiators by 2025. Today, Switzerland is well on its way to meeting that goal. Since the government announced more strict security requirements for HASS in 2018, approximately 60 percent of all irradiators have been removed and, in most cases, replaced with effective and equivalent alternative technologies.

In 2020, the Federal Office of Public Health (FOPH), Switzerland’s licensing and supervisory authority for the use of ionizing radiation, introduced a five-year action plan to prevent radioactive sources from being used for malicious purposes (www.bag.admin.ch/radiss-en). The plan included measures to strengthen the security of and better track radioactive sources throughout their life cycle, as well as to reduce the number of HASS by replacing them with equivalent and effective alternative technologies.

Although the government did not provide any financial support to incentivize a phase out, it did engage in successful dialogues with HASS users about either increasing security around sources in use or switching to alternative sources. Rising costs of future source removals also incentivized users to switch to alternative technologies. In the majority of cases, “the associated benefits of equivalent alternative technologies clearly outweigh the associated risks with the continued use radioactive sources,” said Dr. Thomas Flury, leader of this initiative from the FOPH. The 2018 Radiological Protection Ordinance uses a justification principle which stipulates that licenses for high-activity radioactive sources will only be granted if there is not a more favorable alternative involving lower or no radiation exposure to people and the environment. Every request for extensions of current HASS licenses and every new license request will now include additional reviews of the justification for using a HASS and the viability of alternative technologies for that particular application. As a result, the emergence of new and viable alternative technology will slowly but steadily lead to a reduction of the number of HASS.

Switzerland’s decision to phase out Cesium-137 blood irradiators and other HASS was informed by actions taken by the Office of Radiological Security and other governments, including France and Norway, and by advocacy organizations such as the Nuclear Threat Initiative (NTI), that shared national experiences on the transition process and showed a path forward for the reduction of HASS.

For the first time, the 2020 NTI Nuclear Security Index (NTI Index) included a separate Radioactive Source Security Assessment (“Assessment”) that evaluates the national policies, commitments, and actions to secure radioactive sources and prevent a dirty bomb in 175 countries and Taiwan. A key indicator in this assessment included country actions, commitments, and capacity with respect to the use of alternative technology. The Government of Switzerland was one of a few countries that received credit for committing to replacing HASS with alternative technologies by subscribing to International Atomic Energy Agency Information Circular 910, a vehicle arising from the Nuclear Security Summits for countries to make commitments around radiological security, and publicly declare a regularly requirement, policy, or commitment to implementing alternative technology.

More countries should follow the lead of Switzerland and others that have committed to phase out HASS. Doing so will allow them to reap the security and economic benefits of alternative technology and contribute to building a safer world where the possibility of a terrorist using a dirty bomb is vastly diminished.