Pugwash seminar 8 October: North Korean nuclear weapons – and a new approach to estimating stockpiles

Thursday 8 October, 2pm – 3.30pm Swedish Pugwash will host an online seminar on “North Korean nuclear weapons – and a new approach to estimating stockpiles” with Robert Kelley and Vitaly Fedchenko, both from SIPRI.

Link to the seminar zoom: https://zoom.us/j/91050696649

Read more below.

The international regimes and safeguards against proliferation and threats of nuclear weapons are under strain. In this context North Korea has a crucial and unpredictable role. Swedish Pugwash invites to a seminar focusing on North Korea, with particular focus on new research: a method of estimating the North Korean thermonuclear stockpile. Vitaly Fedchenko and Robert Kelley, both from SIPRI, will present their research.

There have been many open-source publications estimating the size of the North Korean nuclear weapons arsenal, especially triggered by each of the six nuclear tests conducted between 2006 and 2017. Up to this point these publications relied on an assumption that all Highly Enriched Uraium (HEU) and plutonium stocks in North Korea are allocated to fission-only or boosted single-stage weapons. Such studies normally begin with estimates of stocks of fissile material – in this case, plutonium and HEU – in the North Korean military stockpile, assume how much plutonium or HEU would have to be used in each weapon, and arrive at a number of weapons in an arsenal by dividing the first value by the second one.

In the 14 years that have passed since the first nuclear test in October 2006, estimates of North Korean nuclear arsenal became more complicated. On 3 September 2017, Pyongyang conducted a nuclear test that was accepted by many observers as its first and only test of a thermonuclear explosive device. The methodology outlined above uses the estimates of fissile material mass required for fission weapons but does not account for the material requirements of thermonuclear weapons.

Robert Kelley and Vitaly Fedchenko used the publicly known characteristics of US weapons to develop a new method to calculate fissile material requirements of North Korean thermonuclear weapons. They show that North Korean thermonuclear secondaries are likely to require about three times more highly enriched uranium than a simple fission weapon, and this finding clarifies the possible size and composition of the country’s arsenal.

Robert Kelley is Distinguished Research Fellow at SIPRI. He is a veteran in the nuclear weapon and disarmament field with over 35 years in the US Department of Energy nuclear weapons complex, most recently at Los Alamos.

Vitaly Fedchenko is a Senior Researcher with the SIPRI European Security Programme, responsible for nuclear security issues and the political, technological and educational dimensions of nuclear arms control and non-proliferation.

Regarding zoom
Meeting participants should press that link above and follow instructions on their computers. It is advised that the meeting participants would install Zoom on their computers in advance, create an account there under their names, and login into that account. It will be possible to join the meeting without that, but it is strongly recommended to do it with a login. Meeting participants are encouraged to join the meeting 10 to 15 minutes in advance because there are always small glitches, delays, etc.

Thomas Jonter,
Chairman of Swedish Pugwash and Professor of International Relations, Stockholm University