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Topic: Gaseous diffusion

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	Gaseous diffusion - Wikipedia, the free encyclopedia
		Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride through semi-permeable membranes.
		Gaseous diffusion was one of several uranium isotope separation technologies developed as part of the Manhattan Project.
		Large gaseous diffusion plants were constructed by the United States of America, the Soviet Union (including a plant now in Kazakstan), the United Kingdom, France and China.
	en.wikipedia.org /wiki/Gaseous_diffusion (263 words)

	MSN Encarta - Diffusion
		The rate of diffusion is also proportional to a specific property of the substance, which in the case of heat or electricity is called conductivity; in the case of matter, this property is called diffusivity or diffusion coefficient (see Conductor, Electrical; Heat; Resistance).
		In the case of gases, this average speed is greater for smaller molecules, in proportion to the square root of the molecular weight, and is greatly increased by rise in temperature.
		Metallic thorium, for example, diffuses rapidly through metallic tungsten at temperatures around 2000° C (3632° F); the operation of certain vacuum tubes is based on this diffusion.
	encarta.msn.com /encnet/refpages/RefArticle.aspx?refid=761574305 (791 words)

	Gaseous Diffusion Uranium Enrichment
		One of the earliest successful enrichment technique was gaseous diffusion, in which the gas uranium hexafluoride (UF 6) is passed through a porous barrier material; the lighter molecules containing 235 U penetrate the barrier slightly more rapidly, and with enough stages significant separation can be accomplished.
		Diffusion equipment tends to be rather large and consumes significant amounts of energy.
		Gaseous diffusion is unlikely to be the preferred technology of a proliferator due to difficulties associated with making and maintaining a suitable barrier, large energy consumption, the requirement for procuring large quantities of specialized stage equipment, large in-process inventory requirements, and long equilibrium times.
	www.globalsecurity.org /wmd/intro/u-gaseous.htm (583 words)

	MSN Encarta - Fluorine
		However, gaseous fluorine can be prepared by electrolytic techniques, and liquid fluorine may be prepared by passing the gas through a metal or rubber tube surrounded by liquid air.
		The chlorofluorocarbons, odorless and nonpoisonous liquids or gases such as Freon, are used as a dispersing agent in aerosol sprays and as a refrigerant.
		Uranium hexafluoride, the only volatile compound of uranium, is used in the gaseous diffusion process to provide fuel for atomic power plants.
	encarta.msn.com /encyclopedia_761567459/Fluorine.html (606 words)

	The Smyth Report: Chapter X - The Separation Of The Uranium Isotopes By Gaseous Diffusion
		Even if the diffusate gas (the gas which has passed through the barrier) is drawn away by a pump, the relative amount of the heavy isotope passing through the barrier will increase since the light isotope on the near side of the barrier has been depleted by the earlier part of the diffusion.
		For a single diffusion operation, the increase in the rela-tive concentration of the light isotope in the diffused gas com-pared to the feed gas can be expressed in terms of the separation factor r or the enrichment factor, r-1, both defined in para-graph 9.8 of the last chapter.
		For the men working on gaseous diffusion it was a long pull from 1940 to 1945, not lightened by such exciting half-way marks as the first chain-reacting pile at Chicago.
	nuclearweaponarchive.org /Smyth/Smyth10.html (4394 words)

	La France nucleaire/Nuclear France: ENRICHMENT (ENGLISH)
		Gaseous diffusion's heavy use of electricity is dooming the technology [NucF 22.xii.03].
		The intensity of the centrifugal forces being proportional to the mass of the bodies, the atoms of uranium 238 are chased to the edge.
		In addition, the modules are easier to cleanse of uranium 234 and 236 than are the units of a gaseous diffusion plant.
	www.francenuc.org /en_chn/enrichment_e.htm (1558 words)

	K-25 Gaseous Diffusion Process Building \| Manhattan Project Signature Facilities \| History of the Atomic Age \| ...
		Based on the well-known principle that molecules of a lighter isotope would pass through a porous barrier more readily than molecules of a heavier one, gaseous diffusion produced through myriads of repetitions a gas increasingly rich in uranium-235 as the heavier uranium-238 was separated out in a system of cascades.
		Gaseous diffusion was one of three isotope separation processes that provided uranium-235 for the Hiroshima weapon (Little Boy) - the other two being electromagnetic separation and liquid thermal diffusion.
		Gaseous diffusion was the only uranium enrichment process used during the Cold War.
	www.atomicarchive.com /History/sites/K_25.shtml (326 words)

	NRC: Uranium Enrichment
		Gaseous diffusion is the only process being used in the United States to commercially enrich uranium.
		Process: In the gaseous diffusion enrichment plant, the solid uranium hexafluoride (UF6) from the conversion process is heated in its container until it becomes a liquid.
		Hazards: The primary hazard in gaseous diffusion plants include the chemical and radiological hazard of a UF6 release and the potential for mishandling the enriched uranium, which could create a criticality accident (inadvertent nuclear chain reaction).
	www.nrc.gov /materials/fuel-cycle-fac/ur-enrichment.html (741 words)

	Gaseous diffusion -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-11-07)
		Gaseous diffusion is a technology used to produce (additional info and facts about enriched uranium) enriched uranium by forcing gaseous (additional info and facts about uranium hexafluoride) uranium hexafluoride through semi-permeable membranes.
		Gaseous diffusion was one of several uranium (additional info and facts about isotope separation) isotope separation technologies developed as part of the (A former United States executive agency that was responsible for developing atomic bombs during World War II) Manhattan Project.
		It has largely been replaced by the newer (additional info and facts about gas centrifuge) gas centrifuge technology, which requires far less energy to produce the same separation.
	www.absoluteastronomy.com /encyclopedia/g/ga/gaseous_diffusion.htm (268 words)

	Gaseous Diffusion Enrichment Assemblies and Components
		In the gaseous diffusion method of uranium isotope separation, the main technological assembly is a special porous gaseous diffusion barrier, heat exchanger for cooling the gas (which is heated by the process of compression), seal valves and control valves, and pipelines.
		Inasmuch as gaseous diffusion technology uses uranium hexafiuoride (UF6), all equipment, pipeline and instrumentation surfaces (that come in contact with the gas) must be made of materials that remain stable in contact with UF6.
		Because a gaseous diffusion enrichment plant consists of a large number of gaseous diffusion assemblies arranged in cascades, there are many kilometers of cascade header pipework, incorporating thousands of welds with substantial amounts of repetition of layout.
	www.ornl.gov /sci/risk/t_section7.html (4611 words)

	Uranium Enrichment
		The UF output from gaseous diffusion is in two streams - one is increased, or enriched, in its percentage of U-235, and the other is reduced, or depleted, in its percentage of U-235.
		In gaseous diffusion, uranium hexafluoride is divided into two separate streams, and U-235 selectively diffuses from one stream to the other.
		These locations are the gaseous diffusion plants near Paducah, Kentucky, and Portsmouth, Ohio, and at the East Tennessee Technology Park (formerly the K-25 Site) at the Oak Ridge Reservation in Oak Ridge, Tennessee.
	web.ead.anl.gov /uranium/guide/depletedu/enrich/index.cfm (460 words)

	Nuclear Chemistry (Site not responding. Last check: 2007-11-07)
		The gaseous diffusion process is based on molecular effusion, a process that occurs whenever a gas is separated from a vacuum by a porous barrier that contains microscopic holes.
		As difficulties with the gaseous diffusion were overcome, the EMIS process was phased out.
		Three of the processes (thermal diffusion, gaseous diffusion, and electromagnetic separation) were used to produce the U-235 for the first atomic bomb.
	chemcases.com /nuclear/nc-07.htm (946 words)

	Portsmouth Gaseous Diffusion Plant (Site not responding. Last check: 2007-11-07)
		The Portsmouth Gaseous Diffusion Plant is located in south central Ohio, approximately 32 kilometers (20 miles) north of Portsmouth, Ohio, and 112 kilometers (70 miles) south of Columbus, Ohio.
		All of the gaseous diffusion process buildings will be demolished down to their concrete slabs.
		The 1996 life-cycle estimate of $4.0 billion for the Portsmouth Gaseous Diffusion Plant represents a 54 percent decrease from the 1995 estimate of $8.7 billion.
	web.em.doe.gov /bemr96/port.html (6586 words)

	Editorial: Facing Facts - Area Must Prepare For Plant Closing
		Nothing is certain about the future of USEC's gaseous diffusion plants in Paducah and Portsmouth, but the financially struggling company must cut costs and improve its ability to compete in the world market for reactor fuel.
		The operator of the plants, regardless of whether it's USEC or the Department of Energy, is going to have to develop new technology to replace gaseous diffusion.
		If Paducah eventually loses the gaseous diffusion plant, it will be a hard but not necessarily devastating blow to the area's economy.
	www.state.nv.us /nucwaste/news2000/nn10678.htm (860 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations
		The five buildings at the K-25 Site formerly involved in the gaseous diffusion process contain 5000 gaseous diffusion stages as well as support facilities that are internally contaminated with uranium deposits.
		This report documents recent laboratory experiments that were conducted to determine the feasibility of gas-phase decontamination of the internal surfaces of the gaseous diffusion equipment that is contaminated with uranium deposits.
		A gaseous fluorinating agent is used to fluorinate the solid uranium deposits to gaseous uranium hexafluoride (UF{sub 6}), which can be recovered by chemical trapping or freezing.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=10139310 (383 words)

	The Scientific History of the Atomic Bomb
		The rest of the gaseous diffusion plant was shut down in 1987.
		This is a schematic flow diagram for isotope separation by gaseous diffusion showing three stages.
		Associated with each diffuser were two powerful blowers, one to carry the enriched portion of the gas forward to the next stage, the other to take the impoverished portion back down the line to begin a new series of reprocessings.
	www.hibbing.tec.mn.us /programs/dept/chem/abomb/page_id_35050.html (535 words)

	Lanzhou - Chinese Nuclear Forces
		Construction of this gaseous diffusion plant probably began in 1957, and the facility was estimated to be producing weapons grade U-235 at a rate of from 150 to 330 Kgs per year in the 1960s.
		The Gaseous Diffusion Plant [GDP] was in an advanced stage of construction when it was first identified by US intelligence in September 1959.
		Electric power lines, one of which was not completed by mid-1963, connect the gaseous diffusion plant with the 200-250 MW thermal electric station in the city of Lanzhou.
	www.fas.org /nuke/guide/china/facility/lanzhou.htm (760 words)

	ATSDR - PHA - Paducah Gaseous Diffusion (USDOE), Paducah, McCracken County, Kentucky
		The U.S. Department of Energy (DOE)'s Paducah Gaseous Diffusion Plant (PGDP) was added to the U.S. Environmental Protection Agency's Superfund National Priorities List (NPL) on May 31, 1994, because elevated concentrations of trichloroethylene (TCE) and technetium 99 (Tc-99) were found in off-site groundwater (residential wells).
		The primary plant process, gaseous diffusion, is a physical process to enrich uranium hexafluoride (UF)--that is, to increase the percentage of uranium 235 (U-235) above natural concentrations in the UF In the process, solid UF containing about 0.7% U-235 is heated to form a compressed gas.
		The rest of the land was transferred to TVA for the Shawnee Steam Plant and to the Commonwealth of Kentucky for wildlife conservation and recreational purposes [2].
	www.atsdr.cdc.gov /HAC/PHA/paducah/pad_p1.html (11675 words)

	EPA: Federal Register: Paducah Gaseous Diffusion Plant; Portsmouth Gaseous Diffusion Plant; United States Enrichment ...
		Paducah Gaseous Diffusion Plant; Portsmouth Gaseous Diffusion Plant; United States Enrichment Corporation; Notice of Approval of Request for Exemption
		Both facilities are authorized to use Special Nuclear Material (SNM) in the enrichment of natural uranium to prepare low-enriched uranium to be used by others in the fabrication of nuclear fuel pellets and fuel assemblies, although enrichment operations have ceased at PORTS.
		Martin is the Project Manager for the Paducah Gaseous Diffusion Plant.
	www.epa.gov /fedrgstr/EPA-IMPACT/2002/November/Day-12/i28669.htm (1451 words)

	Paducah Gaseous Diffusion Plant (PGDP) - United States Nuclear Forces
		Statement by U.S. Secretary of Energy Bill Richardson on the Paducah Gaseous Diffusion Plant August 8, 1999 -- We are very concerned about recent allegations that past activities at the Paducah Gaseous Diffusion Plant have endangered the health of employees.
		The Paducah Gaseous Diffusion Plant is located in western Kentucky, 10 miles west of the City of Paducah.
		Most UF6 feed material came from the depleted tails produced during normal diffusion operations at PGDP and from Oak Ridge and Portsmouth.
	www.globalsecurity.org /wmd/facility/paducah.htm (1774 words)

	Paducah Publications (Site not responding. Last check: 2007-11-07)
		Report on the Biological Monitoring Program at Paducah Gaseous Diffusion Plant, December 1990 to November 1992.
		Bioavailability study for the Paducah Gaseous Diffusion Plant.
		Thermal discharges from Paducah Gaseous Diffusion Plant outfalls: impacts on stream temperatures and fauna of Little Bayou and Big Bayou creeks.
	www.esd.ornl.gov /BMAP/ky_pubs.htm (234 words)

	ATSDR - PHA - Paducah Gaseous Diffusion (USDOE), Paducah, McCracken County, Kentucky
		ATSDR - PHA - Paducah Gaseous Diffusion (USDOE), Paducah, McCracken County, Kentucky
		According to the information evaluated by ATSDR, under normal operating conditions, the Paducah Gaseous Diffusion Plant currently poses no apparent public health hazard for the surrounding community from exposure to groundwater, surface water, soil and sediment, biota, or air.
		The Public Health Action Plan for the Paducah Gaseous Diffusion Plant describes the public health actions taken and planned to be taken by ATSDR, DOE, and/or other agencies at and near the site, based on the recommendations of this public health assessment.
	www.atsdr.cdc.gov /HAC/PHA/paducah/pad_p3.html (5852 words)

	Portsmouth Gaseous Diffusion Plant
		DOE's Portsmouth Gaseous Diffusion Plant is located in southern Ohio near Piketon.
		The principal process at the facility is the separation of uranium isotopes via gaseous diffusion.
		The Portsmouth facility has been operating since 1954, enriching uranium for use in commercial reactors and for use by the U.S. Navy in power reactors.
	offo2.epa.state.oh.us /DOE/PORTSMOUTH/portsmouth.htm (302 words)

	PACE Worker Health Protection Program \| DOE Gaseous Plants and INEEL: Welcome Page (Site not responding. Last check: 2007-11-07)
		At Department Of Energy Gaseous Diffusion Plants and The Idaho National Laboratory (INL)
		If you worked at the US Department of Energy's Gaseous Diffusion Plants or INL, you are invited to participate in a nationwide program.
		If you take part in the program, all results are confidential and will be given to you.
	www.pace-workerhealth.org (136 words)

	Find in a Library: Independent investigation of the Paducah Gaseous Diffusion Plant
		Independent investigation of the Paducah Gaseous Diffusion Plant
		To find a library, type in a postal code, state, province, or country.
		WorldCat is provided by OCLC Online Computer Library Center, Inc. on behalf of its member libraries.
	worldcatlibraries.org /wcpa/ow/616d0b7abe8884f8a19afeb4da09e526.html (73 words)

	USEC Facilities
		Portsmouth Gaseous Diffusion Plant (PORTS): Who We Are
		The Portsmouth Gaseous Diffusion Plant, located in Piketon, Ohio, began operations in 1954 as part of a U.S. government expansion program for the production of highly enriched uranium to fuel military reactors and nuclear weapons production.
		Later, the Piketon plant, along with its sister enrichment plant in Paducah, Kentucky, took on a different mission: the production of low-enriched uranium to fuel commercial nuclear power plants around the world.
	www.usec.com /v2001_02/HTML/Facilities_PortsOverview.asp (248 words)

	Poll - I think the gaseous diffusion plant investigation should be: - AboutPaducah.com
		Poll - I think the gaseous diffusion plant investigation should be: - AboutPaducah.com
		I think the gaseous diffusion plant investigation should be:
		Learn how to add emoticons to your posting
	www.aboutpaducah.com /poll/first/results.html (39 words)

	RAIS: RA Documents - PGDP (Site not responding. Last check: 2007-11-07)
		Baseline Risk Assessment for Exposure to Polycyclic Aromatic Hydrocarbons at Underground Storage Tanks C-750 A&b, Paducah Gaseous Diffusion Plant, Paducah, Kentucky [KY/EM-170]
		At PGDP, guidance and standardized information is found in Methods for Conducting Human Health Risk Assessments and Risk Evaluations at the Paducah Gaseous Diffusion Plant (DOE/OR/07-1506&D1).
		This manual is currently under revision and an ecological strategy document is currently in development.
	risk.lsd.ornl.gov /maps/old/ra_pgdp.htm (305 words)

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