Subcritical tests - Nuclear testing or not?

Recent US subcritical tests, and equivalent Russian tests, have ignited new discussions on the future of international non-proliferation and disarmame nt regimes. This article presents the rationale for the tests, together wit h brief technical descriptions, and discusses the tests' compatibility with the Comprehensive Test Ban Treaty (CTBT). Concerns regarding the impact of the tests on the ratification of the CTBT are presented and discussed. When, or whether, the treaty will enter into force is still an open questio n, depending on the will and the signature of 44 states with significant nu clear activity. These states include countries like India, Pakistan, Israel and DPRK (Democratic People's Republic of Korea) and all the declared nucl ear weapons states. Among the latter, only Great Britain and France have ra tified the CTBT. The United States and Russia, the only two states that have performed subcr itical tests, still are in a position to set precedence for such tests, bot h prior to and after a Comprehensive Test Ban Treaty. Such a treaty may pro ve to become the essential mechanism for the non-proliferation of nuclear w eapons and nuclear weapons capabilities. If continued, subcritical tests wi ll probably face an increased demand for transparency from the internationa l society, due to the uncertain nature of the tests.