What's New?
.	NRC Chairman Resigns
.	NAS Report on Future Workforce Needs
.	Hodes Award Nominations Request
.	Radiation Risks and Protective Actions
.	June Journal
.	IAEA Conference - Rad Protection in Medicine
.	HPS Mentoring Program Update
.	New Low-Level Waste Site Operational
.	May Newsletter
.	America's Nuclear Future Report

Upcoming Events
.	Canadian Radiation Protection Association Annual Meeting 27-30 May 2012 Halifax, Nova Scotia
.	ACS Undergrad Summer Schools 10 June - 20 July 2012
.	NRC Meeting Webcasts May-June 2012
.	57th Annual HPS Meeting 22-26 July 2012 Sacramento, CA
.	37th Annual Conference of the Australasian Radiation Protection Society (ARPS) 14-17 Oct 2012 Sydney Convention & Exhibition Centre, Darling Harbour
.	International Conference on Radiation Shielding 2-7 Nov 2012 Nara, Japan

23 May 2012

Chain reaction

A reaction that is self-sustaining. In a fission chain reaction, the nucleus of a fissionable atom (see definition for fissionable material) absorbs a neutron and fissions (i.e., breaks apart), releasing additional neutrons. These, in turn, can be absorbed by other fissionable nuclei, releasing still more neutrons. A fission chain reaction is self-sustaining when the number of neutrons released in a given time equals or exceeds the number of neutrons lost by absorption in nonfissionable material or by escape from the system.