plutonium-239

plutonium-239
Name	Plutonium-239
Atomic number	94
Mass number	239
Category	Actinide
Phase	Solid
Density	19.84 g/cm³
Melting point	912.5 °C
Discovered	1940
Discoverers	Glenn T. Seaborg; Edwin M. McMillan; Arthur C. Wahl; Joseph W. Kennedy

plutonium-239 Plutonium-239 is a radioactive isotope of plutonium notable for its role in nuclear weapons and civil reactors. It has been central to twentieth- and twenty-first-century science, technology, and geopolitics involving figures such as J. Robert Oppenheimer, programs like the Manhattan Project, facilities including Hanford Site, and events exemplified by the Trinity test. Research, production, and control of plutonium-239 have engaged institutions such as Los Alamos National Laboratory, Oak Ridge National Laboratory, and international forums like the International Atomic Energy Agency.

Introduction

Plutonium-239 was first synthesized and identified during experiments by Glenn T. Seaborg and colleagues at University of California, Berkeley as part of early atomic research linked to wartime projects including the Manhattan Project and subsequent national laboratories such as Los Alamos National Laboratory. It became a focus of strategic decision-making in administrations of presidents like Harry S. Truman and Dwight D. Eisenhower and informed treaties such as the Treaty on the Non-Proliferation of Nuclear Weapons. Major industrial sites like the Hanford Site and the Sellafield complex shaped production, while scientific advances at institutions including Lawrence Berkeley National Laboratory and Argonne National Laboratory refined isotopic chemistry.

Production and isotopic properties

Plutonium-239 is produced primarily by neutron capture in fertile uranium-238 within reactors built by entities like General Electric and Westinghouse Electric Company; commercial power reactors modeled after designs by Admiral Hyman G. Rickover and research reactors at Brookhaven National Laboratory and Oak Ridge National Laboratory have been used for production. Fuel cycle stages involving facilities such as Sellafield and the Mayak complex include irradiation, cooling, and chemical separation processes developed by scientists at Chalk River Laboratories and influenced by wartime work at Los Alamos National Laboratory. Isotopic vectors include coexisting isotopes such as plutonium-240 and plutonium-241, monitored by programs like Comprehensive Nuclear-Test-Ban Treaty Organization verification efforts and national safeguards from agencies like the International Atomic Energy Agency.

Nuclear properties and reactions

Plutonium-239 undergoes alpha decay and sustains fission upon absorption of thermal neutrons, properties exploited by designers at Los Alamos National Laboratory and tested at sites such as Trinity (nuclear test site) and Nevada Test Site. Its fission cross-section and critical mass informed weapon designs developed by teams including scientists at Los Alamos National Laboratory and policy deliberations in cabinets of leaders like Winston Churchill and Joseph Stalin during the early Cold War. Reactor physics analyses at institutions like MIT and Imperial College London detail chain reactions, neutron moderation strategies used in reactors at Sellafield and Hanford Site, and breeding ratios central to programs advocated by figures such as Edward Teller.

Applications (military and civilian)

Militarily, plutonium-239 became the fissile core in implosion-type devices delivered by programs coordinated among ministries and services including the United States Department of Defense and counterparts in the Soviet Union. Weaponization influenced strategic doctrines debated at conferences such as Yalta Conference and NATO councils, and produced artifacts tested at ranges like Trinity (nuclear test site). Civilian applications have included mixed oxide (MOX) fuel developed by specialty firms and championed by energy ministries in countries such as France and Japan, with industrial partners including Areva and research input from Argonne National Laboratory. Breeder reactor concepts promoted by proponents like Benedict Crowell and explored in projects such as the Fast Flux Test Facility aimed to convert uranium-238 to plutonium-239 for fuel sustainability.

Health, safety, and environmental impact

Health risks associated with plutonium-239 informed occupational standards established by agencies such as the Occupational Safety and Health Administration and radiological protection guidelines from bodies like the International Commission on Radiological Protection. Its radiotoxicity, biopersistence, and alpha-emission hazards were central to responses at incidents involving sites like Windscale fire (Sellafield) and the Kyshtym disaster at Mayak, as investigated by scientists affiliated with World Health Organization studies and national public health agencies including the Centers for Disease Control and Prevention. Environmental contamination concerns led to remediation programs at facilities such as the Hanford Site and cleanup initiatives coordinated with organizations like the Environmental Protection Agency.

Detection, proliferation, and regulation

Detection and accounting for plutonium-239 involve technologies developed at laboratories like Lawrence Livermore National Laboratory and observational networks operated by the Comprehensive Nuclear-Test-Ban Treaty Organization, with analytical methods advanced at universities including University of California, Berkeley and Oxford University. Proliferation control has been central to diplomacy involving actors such as United States Department of State, negotiation rounds under the Treaty on the Non-Proliferation of Nuclear Weapons, and export controls coordinated by regimes like the Nuclear Suppliers Group. Surveillance, safeguards, and security practices implemented by the International Atomic Energy Agency and national entities such as Ministry of Defence (United Kingdom) address theft, diversion, and illicit trafficking issues chronicled in reports by intergovernmental organizations including the United Nations Security Council.

Category:Actinides