Biological Shield

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biological shield

[¦bī·ə¦läj·ə·kəl ′shēld]
A structure designed to prevent the migration of living organisms from one part of a system to another; used on sterilized space probes.
A radiation-absorbing shield used to protect personnel from the effects of nuclear particles or radiation in the vicinity of a nuclear reactor.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Biological Shield


in nuclear power engineering, a complex of structures and materials surrounding a nuclear reactor and its units, the purpose of which is to reduce radioactive emissions to a biologically safe level. A biological shield is designed to absorb neutron and gamma radiation. Water, concrete, graphite, and other materials are used to lessen neutron radiation, and lead and steel to lessen gamma radiation. Since secondary (capture) gamma rays arise during neutron absorption, the materials used in a biological shield are arranged in a definite order: materials with light elements are closest to the radiation source, followed by those with heavy elements. If there are no limitations on the mass and size of a biological shield, only one kind of material is used—that is, the most convenient and cheapest (usually concrete or water).


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
These included strengthening Beira's fast-eroding dunes, decaying sea defences and the restoration of the disappearing belt of mangroves which acted as biological shields protecting the city's population of 500,000 inhabitants.
Like Trawsfynydd Power Station in Gwynedd, Berkeley Magnox Power Station is shut, with the site defuelled and dismantled down to its biological shields and reactor cores within.

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