neutron bomb

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A nuclear bomb that produces great numbers of neutrons but little blast and thus destroys life but spares property.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun An atomic bomb that produces a greater amount of neutrons, and a lesser amount of blast; the intention being to destroy life but not infrastructure.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun atom bomb that produces lethal neutrons with less blast