April 26, 2023
Staff Accomplishment

Milbrath Plays a Key Role in Supporting International Nuclear Explosion Monitoring and Verification

Supporting a world without nuclear explosive testing

Photo of Brian Milbrath

Photo by Andrea Starr | Pacific Northwest National Laboratory

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) was created with one goal: banning nuclear explosions everywhere.

Brian Milbrath, a physicist at Pacific Northwest National Laboratory (PNNL), has supported Preparatory Commission for the CTBT Organization (CTBTO PrepCom) efforts for nearly 15 years. This past year, he was selected as a new Task Leader for the PrepCom’s Working Group B.

“Working Group B is the mechanism through which states provide technical oversight for monitoring and verification capability development. As a Task Leader, I facilitate this process. This involves understanding all aspects of CTBT, where the organization is regarding those items, and the various views on some of these by different states—since consensus of all states is needed for progress to be made. Achieving consensus that keeps the capability development moving forward is an important part of my job.”

What is CTBTO PrepCom?

In 1996, the CTBTO PrepCom was launched to prepare for the treaty's entry into force.

CTBTO PrepCom’s first line of defense is its International Monitoring System (IMS) that spans the globe and includes more than 300 facilities working to detect nuclear explosive tests. IMS data is sent to the International Data Centre in Vienna, Austria, to be analyzed by staff of the Provisional Technical Secretariat and distributed to National Data Centers around the world. Once the treaty enters into force, an international team of inspectors could be sent to gather information on whether a nuclear explosion has occurred in order to ultimately identify who was responsible for a treaty violation.


Milbrath has participated in many of the PrepCom-sponsored expert meetings, field exercises, and workshops as the international community evaluates how to best construct the CTBT’s verification regime. He and colleagues have performed much basic research into the signatures of an underground nuclear explosion and how they might be detected by the IMS or on-site inspectors. PNNL scientists have pioneered research in nuclear explosion monitoring for decades, and these activities are a key nonproliferation effort within the National Security Directorate. New research from PNNL even makes detecting nuclear explosions easier.

For Milbrath, he will lend his expertise to supporting a world without nuclear explosive testing.

“We are using our expertise in nuclear explosion signatures and detection to affect international policy, through the CTBT monitoring and verification regime, to end nuclear explosive testing, and hopefully the proliferation of nuclear arms,” said Milbrath. “My Task Leader role gives me a means to help the states of the world work toward that.”