The nuclear weapons ban treaty and the non-proliferation regime.

The Treaty on the Prohibition of Nuclear Weapons (TPNW), adopted by the United Nations General Assembly in July 2017, has been met with mixed reactions. While supporters have described the Treaty as a watershed in the struggle for disarmament, others have expressed fervent opposition. One of the most serious charges levelled at the TPNW is that it will undermine the long-standing nuclear Non-Proliferation Treaty (NPT), by many regarded as a cornerstone of the international security architecture. Critics have contended that the new agreement risks eroding the system of safeguards designed to prevent the spread of nuclear weapons, derailing disarmament efforts within the NPT framework, and aggravating political division between nuclear and non-nuclear powers. Investigating the legal and political cogency of these arguments, we argue that not only may the TPNW be reconciled with existing legal instruments, the new Treaty supports and reinforces key norms and institutions on which the nuclear non-proliferation and disarmament regime is based. Furthermore, any technical challenges that might arise in the future may be addressed at meetings of states party; the drafters envisioned a dynamic process of institutional adaptations and expansion. The main challenge facing advocates of the Treaty is political: convincing the nuclear-armed states to disarm.

The 2014 Integrated Field Exercise of the Comprehensive Nuclear-Test-Ban Treaty revisited: The case for data fusion.

The International Monitoring System of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) uses a global network of radionuclide monitoring stations to detect evidence of a nuclear explosion. The two radionuclide technologies employed-particulate and noble gas (radioxenon) detection-have applications for data fusion to improve detection of a nuclear explosion. Using the hypothetical 0.5 kT nuclear explosive test scenario of the CTBTO 2014 Integrated Field Exercise, the intrinsic relationship between particulate and noble gas signatures has been examined. This study shows that, depending upon the time of the radioxenon release, the particulate progeny can produce the more detectable signature. Thus, as both particulate and noble gas signatures are inherently coupled, the authors recommend that the sample categorization schemes should be linked.

Circulation of cosmogenic 22Na using the global monitoring network of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO).

Using a recently published global data set of 22Na and 7Be from the global monitoring network of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), atmospheric circulation and stratosphere-troposphere interactions are examined. Cosmogenic 22Na has a half-life well-suited to environmental processes with durations from several months to a decade. Combined with corresponding 7Be observations, these two cosmogenic isotopes form a useful environmental tracer and new radiochronometer to study physical interactions of air masses in the stratosphere and troposphere.

Time resolution requirements for civilian radioxenon emission data for the CTBT verification regime.

The capability of the noble gas component of the International Monitoring System as a verification tool for the Comprehensive Nuclear-Test-Ban Treaty is deteriorated by a background of radioxenon emitted by civilian sources. One of the possible approaches to deal with this issue, is to simulate the daily radioxenon concentrations from these civilian sources at noble gas stations by using atmospheric transport models. In order to accurately quantify the contribution from these civilian sources, knowledge on the releases is required. However, such data are often not available and furthermore it is not clear what temporal resolution such data should have. In this paper, we assess which temporal resolution is required to best model the 133Xe contribution from civilian sources at noble gas stations in an operational context. We consider different sampling times of the noble gas stations and discriminate between nearby and distant sources. We find that for atmospheric transport and dispersion problems on a scale of 1000 km or more, emission data with subdaily temporal resolution is generally not necessary. However, when the source-receptor distance decreases, time-resolved emission data become more important. The required temporal resolution of emission data thus depends on the transport scale of the problem. In the context of the Comprehensive Nuclear-Test-Ban Treaty, where forty noble gas stations will monitor the whole globe, daily emission data are generally sufficient, but for certain meteorological conditions, better temporally resolved emission data are required.