Every day, thousands of patients worldwide undergo medical tests, diagnostics, and treatments that use radioactive materials.  These vital materials, such as molybdeum-99 (Mo-99), must be produced continuously to keep up with demand.   One consequence of some Mo‑99 production is the release of emissions that can complicate international efforts to detect secret nuclear explosions.  Nuclear explosion monitoring networks, such as the International Monitoring System (IMS) operated under the Comprehensive Nuclear-Test-Ban Treaty (CTBT), use sensors that can detect gases released by a nuclear explosion.  Mo-99 production emissions from a specific type of production process can interfere with these sensors, complicating the ability of the monitoring networks to detect a nuclear explosion such as the announced North Korean nuclear explosive tests. 

Improving U.S. and international nuclear explosion detection efforts is a key objective of the National Nuclear Security Administration’s (NNSA) mission to prevent nuclear weapons proliferation.  The NNSA and experts at its National Laboratories play a vital role in strengthening the monitoring and verification capability of the Preparatory Commission for the CTBT Organization (CTBTO PrepCom).  NNSA experts work closely with the CTBTO PrepCom to operate, maintain and improve the capabilities of the worldwide IMS, supported by the International Data Centre in Vienna, Austria.

The CTBTO PrepCom, the Belgian Research Institute (SCK•CEN), and the U.S. Department of Energy’s Pacific Northwest National Laboratory (PNNL) co-hosted a workshop in Brussels, Belgium from May 11‑14, 2015, to explore innovative ways of reducing the impact of emissions from fission-based medical isotope production on nuclear explosion monitoring networks.  This event, the fifth in the series of Workshops on the Signatures of Medical and Industrial Isotope Production (WOSMIP), brought together over 100 international representatives from the nuclear explosion monitoring and isotope production communities.  

To date, six current or future Mo-99 producers have signed a voluntary agreement to collaborate with the CTBTO PrepCom to address the issue.  The CTBTO PrepCom Executive Secretary encouraged other producers to sign the Radioxenon Emissions Pledge and seek ways to reduce their emissions.

NNSA also stressed the importance of reducing emissions while ensuring the reliable supply of Mo-99 produced without the use of highly enriched uranium.    

recent P5 statement for the 2015 Treaty on the Non-Proliferation of Nuclear Weapons Review Conference also highlighted this emissions issue.  The statement said “The P5 recognize that while medical isotope production is a critically important activity and while the objective of ensuring the security of supply of medical radioisotopes is of utmost importance, they share a common interest in minimizing the interference of xenon radioisotope releases with global radioactive monitoring activity.  The P5 believe that all states should engage with producers in their regions to assess the amount of emission and to reduce where it is possible their negative impact on the environment through minimization of emission from fission-based medical isotope production.”