Primary Physics
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AWE’s Primary Physics Group is the authority for the physics designs of the primary component of warheads in the UK nuclear stockpile.
In primary devices, a high energy yield is produced through fissions of heavy elements. The output is used to effect the operation of the secondary component. The fissile materials used in primary warheads are plutonium and enriched uranium.
The core aim of the Primary Physics Group is to understand the functioning and performance of all aspects of primary warheads, in order to underwrite the performance of the warheads in the stockpile, and to have the capability to design any potential new warheads if required.
We must take into consideration safety, reliability, weight, compactness and efficiency. To achieve this understanding, we evaluate and interpret an array of experimental evidence and also perform and analyse numerical simulations of these experiments.
The most important and relevant experimental data comes directly from past explosions of an actual warhead in an underground test – data from such tests performed numerous years ago is still crucial in our research. Of course, AWE no longer performs actual testing, nor has fielded any underground tests in the last decade, in accordance to the international Comprehensive Nuclear Test Ban Treaty. Explaining the results of these experiments is the ultimate test of our understanding of primary physics, and reproducing the measured output is the ultimate aim of our code simulations.
Other relevant experimental data is obtained from hydrodynamic experiments fired by AWE’s Hydrodynamics department. These experiments usually make use of high explosives so that data can be obtained from the high pressure and temperature regions that are of most interest to us.
Many of these experiments have a similar geometry to that of an actual weapon, while others use simplified geometries or are designed to look at one particular aspect of a hydrodynamic implosion. It is not possible to fire such experiments at full scale using plutonium, but high Z materials are used to simulate it. A variety of simulants are used because no one simulant exhibits all the features of the behaviour of plutonium.
Primary Safety
Safety is AWE’s highest priority. A nuclear weapon is fundamentally designed to release an enormous amount of energy. The stringent safeguards in the arming system ensure that this full energy release will only occur in the desired circumstances of a deliberate authorised operation.
Throughout its lifetime, a nuclear weapon is handled with extreme care. During transport and storage, it is protected by extremely robust containers which provide protection against even very severe accidents.
In primary devices, a high energy yield is produced through fissions of heavy elements. The output is used to effect the operation of the secondary component. The fissile materials used in primary warheads are plutonium and enriched uranium.
The core aim of the Primary Physics Group is to understand the functioning and performance of all aspects of primary warheads, in order to underwrite the performance of the warheads in the stockpile, and to have the capability to design any potential new warheads if required.
We must take into consideration safety, reliability, weight, compactness and efficiency. To achieve this understanding, we evaluate and interpret an array of experimental evidence and also perform and analyse numerical simulations of these experiments.
The most important and relevant experimental data comes directly from past explosions of an actual warhead in an underground test – data from such tests performed numerous years ago is still crucial in our research. Of course, AWE no longer performs actual testing, nor has fielded any underground tests in the last decade, in accordance to the international Comprehensive Nuclear Test Ban Treaty. Explaining the results of these experiments is the ultimate test of our understanding of primary physics, and reproducing the measured output is the ultimate aim of our code simulations.
Other relevant experimental data is obtained from hydrodynamic experiments fired by AWE’s Hydrodynamics department. These experiments usually make use of high explosives so that data can be obtained from the high pressure and temperature regions that are of most interest to us.
Many of these experiments have a similar geometry to that of an actual weapon, while others use simplified geometries or are designed to look at one particular aspect of a hydrodynamic implosion. It is not possible to fire such experiments at full scale using plutonium, but high Z materials are used to simulate it. A variety of simulants are used because no one simulant exhibits all the features of the behaviour of plutonium.
Primary Safety
Safety is AWE’s highest priority. A nuclear weapon is fundamentally designed to release an enormous amount of energy. The stringent safeguards in the arming system ensure that this full energy release will only occur in the desired circumstances of a deliberate authorised operation.
Throughout its lifetime, a nuclear weapon is handled with extreme care. During transport and storage, it is protected by extremely robust containers which provide protection against even very severe accidents.