Nuclear Testing

Introduction

Like any weapon, the development and validation of a nuclear weapon needs different
nuclear and non-nuclear tests. These tests include tests of individual component, system
tests and potentially a full nuclear test of the functioning weapon. Tests of individual
components are similar to the needs for conventional weaponry.

In addition to these routine tests, fission weapon development needs, or at least gets much
benefit from, certain types of test which are only required specifically for nuclear weapons.
Implosion designs need hydrodynamic tests - these experiments make examinations of
materials under extreme shock compression.

Hydrodynamic Testing

Hydrodynamic tests are used in order to perfect shock compression techniques and designs.
A secondary aim can include the generation of data with regard to the properties of
materials under shock compression conditions. It is very difficult to make measurements of
such experiments because it is necessary to take them through expanding explosion gases. It
is possible to conduct hydrodynamic tests on complete implosion weapon designs for
uranium weapons simply after substituting natural or depleted uranium for actual
weapons-grade uranium.

Hydrodynamic experiments can be employed to collect equation of state (EOS) data
which go up to quite high shock pressures. Typically, advanced weapon programs employ
sophisticated experiments such as gas guns to generate very high pressure shock data. Full-sized
hydrodynamic tests of inert weapon designs need special test facilities. These facilities
include heavy reinforcement and have provision for instrumentation.

Sub-Critical Testing

It is also possible to use hydrodynamic tests to collect data with regard to the properties of
nuclear materials with actual nuclear materials. The radioactivity and toxicity of plutonium
make hydrodynamic tests many times more hazardous to perform and care is essential to
avoid criticality and nuclear yield. Very little or no high-pressure shock equation of state data
have been published with regard to plutonium. It is possible to employ uranium to be a
plutonium substitute to some extent, but the unique properties of plutonium limit this utility
to some degree.

Nuclear Testing

Since 1945 there have been approximately 2050 nuclear explosions. Over 500
of these occurred above ground. America conducted the first nuclear test, which had the codename
“Trinity”. This was a test of the “Gadget” device which was later dropped on Nagasaki. America conducted the biggest number of tests; approximately 1054 in comparison with
approximately 715 nuclear tests which were carried out by the Soviet Union. France
conducted 210 nuclear tests, UK and China conducted approximately 45. India conducted a
“peaceful nuclear explosion” for the first time in 1974, and tested again in 1998. Pakistan
conducted their first test in 1998 also. India and Pakistan have tested approximately 6
devices. The Democratic People’s Republic of Korea has tested a nuclear device in 2006, 2009, 2013 and two devices in 2016.

Although every nuclear test is to a certain degree political in character, the main motivation
for a nuclear test is to progress scientific understanding of how a nuclear weapon works.
This allows advancements in nuclear weapon design; creation of larger yields and smaller-
and-smaller warheads.