Variable yield

Variable yield

Variable yield — or dial-a-yield — is an option available on most modern nuclear weapons. It allows the operator to specify a weapon's yield, or explosive power, allowing a single design to be used in different situations. For example, the Mod-10 B61 bomb had selectable explosive yields of 0.3, 5, 10 or 80 kt, depending on how the ground crew set a dial inside the casing when it was loaded onto an aircraft.

Variable yield technology has existed since at least the early 1960s. Examples of variable yield weapons include the B61 nuclear bomb family, B83, W80, W85 and WE177A warheads.

Most modern nuclear weapons are Teller–Ulam design type thermonuclear weapons, with a fission primary stage and a fusion (or fission) secondary stage which is collapsed by the energy from the primary. These offer at least three methods to vary yield:

  • Varying primary yield by boosting with fusion, using small amounts of deuterium / tritium gas inside the primary fission bomb to increase its yield. Typically, the gas is injected a few seconds before detonation and the amount used can be preset.
  • Varying primary yield by varying the timing or use of external neutron initiators (ENIs).[1] These are small particle accelerators which cause a brief fusion reaction by accelerating deuterium into a tritium target (or potentially vice versa), producing a short energetic pulse of neutrons. Precise timing of the ENI pulse as the nuclear primary's pit is collapsing can significantly affect yield, and the rate of neutron injection can also be controlled.
  • Shutting down the thermonuclear secondary, either by firing the primary at low enough yield that it does not compress the secondary sufficiently to ignite, or by blocking energy transport inside the warhead briefly as the primary is firing using shutters or a similar mechanism. If the primary's energy starts to disperse through the radiation case before being focused on the secondary then the secondary will likely never detonate.

All current British nuclear warheads incorporate variable yield technology as standard.[2]

See also

References

  1. ^ 4.1.8.2 External Neutron Initiators (ENIs), Nuclear Weapons FAQ, accessed 2009-06-17
  2. ^ http://nuclearweaponarchive.org/Uk/UKArsenalRecent.html Summary of UK Arsenal report

External links


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Yield management — Yield management, also known as revenue management, is the process of understanding, anticipating and influencing consumer behavior in order to maximize revenue or profits from a fixed, perishable resource (such as airline seats or hotel room… …   Wikipedia

  • Variable universal life insurance — (often shortened to VUL) is a type of life insurance that builds a cash value. In a VUL, the cash value can be invested in a wide variety of separate accounts, similar to mutual funds, and the choice of which of the available separate accounts to …   Wikipedia

  • Variable-rate mortgage — A variable rate mortgage or floating rate mortgage is a mortgage loan where the interest rate varies to reflect market conditions. The interest rate will normally vary with changes to the base rate of the central bank and reflects changing costs… …   Wikipedia

  • Variable Interest Rate — An interest rate on a loan or security that fluctuates over time, because it is based on an underlying benchmark interest rate or index that changes periodically. The obvious advantage of a variable interest rate is that if the underlying… …   Investment dictionary

  • Variable — A variable (pronEng|ˈvɛərɪəbl) is an attribute of a physical or an abstract system which may change its value while it is under observation. Examples include the height of a child, the temperature across a state, or the input to a function. This… …   Wikipedia

  • Variable-width encoding — This article is about the storage of text in computers. For the transmission of data across noisy channels, see variable length code. A variable width encoding is a type of character encoding scheme in which codes of differing lengths are used to …   Wikipedia

  • Variable-message sign — Sign over Interstate 94 in Saint Paul, Minnesota, advising of a road blockage during a winter storm …   Wikipedia

  • Variable pricing — Most firms use a fixed price policy. That is, they examine the situation, determine an appropriate price, and leave the price fixed at that amount until the situation changes, at which point they go through the process again. The alternative has… …   Wikipedia

  • Variable Rate Mortgage — A type of home loan in which the interest rate is not fixed. The two most common types of mortgages in the United States are fixed rate and variable rate (also called adjustable rate). With a fixed rate mortgage, the interest rate does not change …   Investment dictionary

  • Variable range hopping — IntroductionVariable range hopping or Mott variable range hopping, is a model describing low temperature conduction in strongly disordered systems with localized states. [Mott, N.F., Phil. Mag. ,19,835,1969] It has a characteristic temperature… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”