The total DOE plutonium acquisitions for the period 1944 to September 30, 1994, were 111.4 metric tons. Of the 111.4 MT plutonium acquired, 104 MT were produced in Government reactors; 103.4 MT in production reactors, and 0.6 MT in nonproduction reactors. In addition, 1.7 MT were acquired from U.S. civilian industry, and 5.7 MT from foreign countries. This section describes each of the acquisition categories in detail.
It should be noted that the acquisitions detailed in this report do not include small quantities of plutonium received from foreign governments under Military Agreements for Cooperation per Section 91C of the Atomic Energy Act of 1954. These transactions remain classified for national security reasons and are not discussed in this report.
As a result of treaty obligations, legislation, and intergovernmental policy decisions, some nonweapon grade plutonium acquired from U.S. civilian and foreign sources has been designated "restricted use" plutonium. Restricted use plutonium cannot be used in nuclear weapons. Restricted use plutonium is located primarily at the Hanford Site, the Savannah River Site, the Idaho National Engineering Laboratory facilities, and the Argonne National Laboratory West.
Figure 5 shows a comparison of the quantities of plutonium received from the four acquisitions categories that are used in this report.
The United States Government has used 14 plutonium production reactors at the Hanford and Savannah River sites to produce plutonium for the U.S. nuclear weapons stockpile and DOE research and development programs. From 1944 to 1994, these reactors produced 103.4 [note 12] metric tons of plutonium; 67.4 MT at Hanford, and 36.1 at Savannah River.
Nine production reactors were built at the Hanford Site between 1944 and 1963. All were graphite moderated, light-water cooled reactors located in the north sector of the Site along the Columbia River. The first eight had single-pass (once-through) cooling systems, while the ninth, N-Reactor, had a recirculating primary coolant system and operated at higher pressures and coolant temperatures than the older reactors.
The chief product of the Hanford reactors was weapon grade plutonium, however, non-weapon grade plutonium and occasionally Tritium, Polonium-210, Uranium-233, Thulium-170, Iridium-192, and other special use isotopes were also produced. Specific dates of operations of the Hanford production reactors follow:
|Name||Start-Up Date||Shutdown Date|
|B-Reactor||September 1944||February 1968|
|D-Reactor||December 1944||June 1967|
|F-Reactor||February 1945||June 1965|
|H-Reactor||October 1949||April 1965|
|DR-Reactor||October 1950||December 1964|
|C-Reactor||November 1952||April 1969|
|KW-Reactor||January 1955||February 1970|
|KE-Reactor||April 1955||January 1971|
|N-Reactor||December 1963||January 1987|
The Hanford B, D, F and DR-Reactors were designed to operate at 250 megawatts (MW) thermal. H-Reactor was designed to operate at 400 MW, C-Reactor at 650 MW, and KW and KE-Reactors at 1800 MW each. N-Reactor was designed to operate at 4000 MW.
In the 1950's, major upgrades were made at the first eight Hanford reactors to increase production. By the early 1960's, the following power levels had been achieved and sustained: 2210 MW at B-Reactor, 2165 MW at D-Reactor, 2040 MW at F-Reactor, 2140 MW at H-Reactor, 2015 MW at DR-Reactor, 2500 MW at C-Reactor, and 4400 MW each at KE and KW-Reactors. However, an administrative power limit of 4000 MW was imposed by the Atomic Energy Commission at the KE and KW-Reactors.
N-Reactor's power level did not change substantially over the years, and in 1966 a generating plant was constructed to convert part of the reactor's heat output to the production of electricity.
The Hanford reactors produced 67.4 metric tons of plutonium including 54.5 MT of weapon grade plutonium through 1987 before the last Hanford production reactor was shutdown. The annual fiscal year Hanford production is presented in Figure 6 and Table 2.
In the mid-1980's, to increase the availability of weapon grade plutonium, Hanford initiated the Fuel Segregation Program. This program took advantage of the fact that some of the fuel assemblies discharged during the N-Reactor fuel grade campaigns contained weapon grade plutonium.
Plutonium production is based on fuel exposure by neutron bombardment, the amount of time that fuel is in a reactor, reactor heat/power operating conditions and the location of the fuel within the reactor. The neutron flux produced in a reactor varies across the reactor core. The exposure received by a fuel element at the end of a given tube will be different from the exposure received in the middle of the tube, where fuel irradiation is most concentrated.
Neutron flux variations also occurs between fuel elements having different positions within a reactor. Therefore, even if a reactor is operating in a fuel grade plutonium production mode, flux variations will cause the irradiated fuel to contain some weapons grade plutonium. By using special measuring instruments and understanding of the above reactor properties, weapon grade plutonium was identified and chemically separated from the irradiated fuel.
From 1983 through 1984 Hanford extracted approximately 425 kg of weapon grade plutonium by the Fuel Segregation Program. While sorting increased the weapon grade plutonium inventory by 425 kg of plutonium, it also decreased the fuel grade plutonium by an equivalent amount.
Five heavy water production reactors were built at the Savannah River Site (SRS) near Aiken, South Carolina between 1953 and 1955. The production reactors used heavy water as a moderator primary cooling medium. The primary coolant was completely contained in the reactor building. Heat was extracted through the use of heat exchangers cooled by water from the Savannah River.
While the main products of the Savannah River reactors were weapon grade plutonium and tritium, a variety of isotope products including Uranium-233, Americium-242, Curium-244, Polonium-210, Cobalt-60, Plutonium-238, Plutonium-242, and Californium-252 were also produced.
The order and dates of operations of the production reactors at the Savannah River Site are as follows:
|Name||Start-Up Date||Shutdown Date|
|R-Reactor||December 1953||June 1964|
|P-Reactor||February 1954||August 1988|
|K-Reactor||October 1954||Standby July 1992|
|L-Reactor||July 1954||June 1988|
|C-Reactor||March 1955||June 1985|
The five Savannah River reactors each were originally designed to operate at less than 500 megawatts (MW) thermal. During the period from 1955 through 1965, the thermal power levels of the reactors were increased to approximately 2500 MW by engineering enhancements such as installing larger pumps, more heat exchangers, larger pipes and optimizing the reactor physics, internal coolant flow designs and improved fuel element designs. Currently all reactors are shut down except for K-Reactor which is being maintained in cold standby, as a near term contingency for tritium production.
The Savannah River reactors produced primarily weapon grade plutonium with a Pu-240 content of about 6 percent. Starting in 1981, to increase the availability of plutonium for the weapons program, the Savannah River P, K, C-Reactors were operated to produce weapon grade plutonium with a 3 percent Pu-240 content. This method of operating accelerated reactor operations, decreased target irradiation time, and increased fuel throughput.
From 1982 through 1990 the DOE was able to convert approximately 2.8 MT of fuel grade plutonium to weapon grade by blending the 3 percent Pu-240 with fuel grade plutonium. While blending increased the weapon grade plutonium inventory by 2.8 MT of plutonium, it also decreased the fuel grade plutonium by an equivalent amount. Of the 2.8 MT of fuel grade plutonium blended to weapon grade, 2.4 MT was blended at Savannah River, and 0.4 MT at Hanford.
The reactors in this category were not operated to produce plutonium, but rather were U.S. military reactors, government experimental power-reactors, government power reactors, naval propulsion reactors, and government test and research reactors. They included several DOE-owned and public utility-operated prototype reactors.
From 1952 to 1994 the nonproduction reactors, while operating to meet their respective missions, produced a total of 0.6 metric tons of plutonium; 0.1 MT weapon grade plutonium and 0.5 MT fuel grade plutonium. Quantities of plutonium produced in Government nonproduction reactors are shown by fiscal year in Figure 8 and Table 4.
Examples of nonproduction reactors that produced plutonium include the Experimental Breeder Reactor No. 2 in Idaho, the Fast Flux Test Facility at Hanford, the Shippingport Reactor in Pennsylvania, the La Crosse Boiling Water Reactor in Wisconsin, the Boiling Nuclear Superheat Reactor in Puerto Rico and the NS Savannah, the only U.S. cargo-passenger ship to be driven by nuclear power.
A complete listing of AEC, ERDA, DOE and DoD reactors including location, type, power, and operating time frames can be found in the report, Nuclear Reactors Built, Being Built, or Planned, DOE/OSTI-8200 (Revision 58) August 1995.
The U.S. Civilian Industry category is primarily comprised of plutonium purchased by the Department from civilian power reactor operators under the Plutonium Credit Activity and other U.S. civilian acquisitions.
A total of 1.7 metric tons of fuel grade plutonium was acquired under this category; 0.9 from the Plutonium Credit Activity, and 0.8 from other civilian acquisitions. Through 1983, this plutonium could be used in nuclear weapons activities. After 1983, legislation restricted the use of plutonium acquired from U.S. civilian industry to non-weapon activities.
In the 1950's, commercial utilities began returning spent fuel to the AEC under a program called the Plutonium Credit Activity. This program, established by the U.S. Congress in the Atomic Energy Act of 1954, provided "credit" for plutonium produced in commercial nuclear reactors operating on uranium fuel purchased or leased from the AEC. Although the uranium in the civilian power reactor industry in the 1950's and early 1960's was owned by the AEC and leased to the utility companies, the plutonium produced during operation of these reactors was owned by the utility companies.
The U.S. Government paid the utilities $10.4 million for approximately 0.9 MT of plutonium. Most of the plutonium purchased under the Plutonium Credit Activity was reprocessed at Nuclear Fuels Services (NFS) West Valley. NFS West Valley, located near Buffalo, New York, was the only private facility in the U.S. to reprocess spent nuclear fuel. In addition to commercial spent fuel, NFS West Valley also reprocessed government owned spent fuel and liquid residues.
Additional information on NFS West Valley is available in the DOE report, Plutonium Recovery from Spent Fuel Reprocessing by Nuclear Fuel Services at West Valley, New York from 1966 to 1972, February 1996.
In addition to the plutonium purchased under the Plutonium Credit Activity, the DOE received an additional 0.8 metric tons of fuel grade plutonium from other U.S. civilian sources.
Of the 0.8 metric tons plutonium received, 0.7 MT was in spent fuel. Most of this material was received for storage and monitoring, and eventual disposal. Almost all of this spent fuel is currently stored at three facilities, the Idaho National Engineering Laboratory, the Savannah River Site, and at the West Valley Demonstration Project. As shown in Table 6, the spent fuel came from U.S. commercial light-water reactors, one-of-a-kind commercial reactors, and special fuels associated with universities, and private industry.
In addition to spent nuclear fuel, the DOE also received 0.1 MT plutonium from commercial industry, universities, and hospitals, primarily in the form of scrap, sources, and mixed oxides. Generally, these were the return of U.S. Government plutonium that had been previously transferred to industry under various agreements.
This category consists of plutonium received by barter under the 1958 U.S. and U.K. Mutual Defense Agreement, as well as plutonium received from foreign countries under Agreements for Cooperation for the peaceful uses of atomic energy. Total plutonium received from foreign countries was 5.7 [note 20] metric tons of primarily fuel grade plutonium; 5.4 MT under the Mutual Defense Agreement with the United Kingdom, and 0.4 MT from Agreements for Cooperation.
Under the Mutual Defense Agreement with the United Kingdom from 1959 to 1980, the United States acquired a total of 5.4 MT of plutonium (5360 kilograms) in exchange for 6.7 kilograms of tritium and 7.5 MT of highly enriched uranium.
Programs for international cooperation in the peaceful uses of atomic energy are carried out largely through Agreements for Cooperation with the IAEA, the European Atomic Energy Community (Euratom), and through bilateral agreements with other countries, as authorized by the Atomic Energy Act of 1954, as amended. Under these programs, the Department exchanged information on peaceful uses of nuclear materials with other nations and provided chemical reprocessing services to foreign countries.
A total of 0.4 metric tons of plutonium were obtained under these agreements, including 254 kg of plutonium from Canada, 79 kg of plutonium from Taiwan, and 50 kg from others.