Gaseous diffusion - Revision history

Jmdonev: 1 revision imported

2019-09-04T20:39:11Z

1 revision imported

← Older revision	Revision as of 20:39, 4 September 2019
(No difference)

energy>Jmdonev at 19:43, 4 September 2019

2019-09-04T19:43:44Z

← Older revision		Revision as of 19:43, 4 September 2019
Line 1:		Line 1:
	[[~~Category:Done 2017-07-01]]~~		#REDIRECT [[Gaseous diffusion uranium enrichment]]
	[[Uranium]] that is found in the Earth's crust is made up of 99.289% <sup>238</sup>U and 0.711% <sup>235</sup>U, which are two [[isotope]]s of uranium. In order to use uranium in [[nuclear power plant]]s, uranium ore must be [[Uranium mining\|mined]], milled and then enriched to a higher percentage of <sup>235</sup>U. <onlyinclude>'''Gaseous diffusion''' was the first economic enrichment process of uranium to be successfully developed.<ref name="r1">John R. Lamarsh, Anthony J. Baratta. (June 28, 2016). ''Introduction to Nuclear Engineering''. Third Edition. Upper Saddle River, NJ, U.S.A:Prentice Hall, 2001.</ref></onlyinclude>		[[Category:Done 2019-09-05]]

	[[File:gaseous diffusion.jpg\|400px\|framed\|center\|Figure 1. Portsmouth Gaseous diffusion plant, Ohio.<ref>Energy.gov. (June 29, 2016). ''PORTSMOUTH SITE DESCRIPTION'' [Online]. Available: http://energy.gov/pppo/portsmouth-site-description</ref>]]

	~~==Methodology==~~

	[[File:diffuser.PNG\|400px\|thumb\|right\|Figure 2. Cross sectional diagram of the diffuser, showing the low and high pressure areas as well as the high pressure feed stream, enriched and depleted flows.<ref>Global Security (September 21, 2016). ''Gaseous Diffusion Uranium Enrichment'' [Online]. Available: http://www.globalsecurity.org/wmd/intro/u-gaseous.htm</ref>]]


	Gaseous diffusion~~, like all [[~~uranium enrichment]] processes, utilizes the difference in [[mass]] between the <sup>235</sup>U isotope and the <sup>238</sup>U isotope. Because <sup>238</sup>U possesses three more [[neutron]]s in its [[nucleus]] compared to <sup>235</sup>U, it has a higher mass. The gaseous diffusion process is therefore based on the fact that, in a mixture of two gases, on average the lighter [[molecule]]s travel faster than the heavier ones. <ref name="r1"/> Due to this observation, if the gases are contained within a container, the lighter molecules will come into contact with the walls of the container more frequently. If the walls of the container were to be made of a semipermeable membrane, such that individual gas molecules could pass through but not enough to create a mass-flow through, then more of the lighter molecules will pass through the container. <ref name="r1"/> The gas leaving the container is therefore slightly enriched in the lighter molecules and the gas that did not pass through the semipermeable membrane is depleted. Figure 2 shows a picture of a diffuser and its container, membrane and piping which is used in some gaseous diffusion plants.

	~~==Gaseous diffusion process==~~
	[[~~File~~:gdc.jpg\|400px\|framed\|right\|Figure 3. Diffusers set up in a cascade. Enriched uranium comes out of the upper pipes and is sent upward through the cascade while the depleted uranium comes out of the bottom pipes and is sent downward through the cascade.<ref>U.S. Department of Energy (September 21, 2016). ''The Manhattan Project'' [Online]. Available: https://www.osti.gov/opennet/manhattan-project-~~history/Events/1942~~-~~1944_ur/k-25_working.htm</ref>~~]]

	The gaseous diffusion process utilizes [[uranium hexafluoride]], UF<sub>6</sub>, because although it is a [[solid]] at room [[temperature]] it is easily vaporized. <ref name="r1"/> UF<sub>6</sub> is not only convenient for its volatility, but also due to the fact that fluorine only consists of the isotope <sup>19</sup>F, meaning the difference in molecular weights for UF<sub>6</sub> are purely reliant on <sup>235</sup>U and <sup>238</sup>U.<ref name="r1"/> Here arises another problem however, for the masses of the two uranium isotopes are so nearly equal there is very little separation of <sup>235</sup>UF<sub>6</sub> and <sup>238</sup>UF<sub>6</sub> with one pass through a diffuser.<ref name="r1"/> Therefore a [[cascade process]] is needed to obtain any measurable amount of enrichment. Figure 3 on the right depicts diffusers set up in a cascade. The feed stream at diffuser 1 is the UF<sub>6</sub> prior to enrichment (meaning it will contain 0.711% <sup>235</sup>U and 99.289% <sup>238</sup>U) and marks the start of the cascade. There will be hundreds to thousands of diffusers on the upward or enriching side as well as on the downward or depleted side. The slightly enriched UF<sub>6</sub> is sent up the cascade process to the next diffuser where it will be enriched again. The slightly depleted UF<sub>6</sub> will be sent downward through the cascade where it will also be enriched again. In this way, the enriched uranium keeps getting enriched and sent onward, and the depleated uranium also gets enriched and sent onward. The depleated uranium always gets sent downward where it will eventually be ejected from the downward stream as depleated uranium.


	~~==References==~~
	~~{{reflist}}~~

Jmdonev: 1 revision imported

2017-08-29T01:46:46Z

1 revision imported

← Older revision	Revision as of 01:46, 29 August 2017
(No difference)

Jmdonev at 21:42, 28 July 2017

2017-07-28T21:42:50Z

New page

[[Category:Done 2017-07-01]]
[[Uranium]] that is found in the Earth's crust is made up of 99.289% 238U and 0.711% 235U, which are two [[isotope]]s of uranium. In order to use uranium in [[nuclear power plant]]s, uranium ore must be [[Uranium mining|mined]], milled and then enriched to a higher percentage of 235U. <onlyinclude>'''Gaseous diffusion''' was the first economic enrichment process of uranium to be successfully developed.<ref name="r1">John R. Lamarsh, Anthony J. Baratta. (June 28, 2016). ''Introduction to Nuclear Engineering''. Third Edition. Upper Saddle River, NJ, U.S.A:Prentice Hall, 2001.</ref></onlyinclude>

[[File:gaseous diffusion.jpg|400px|framed|center|Figure 1. Portsmouth Gaseous diffusion plant, Ohio.<ref>Energy.gov. (June 29, 2016). ''PORTSMOUTH SITE DESCRIPTION'' [Online]. Available: http://energy.gov/pppo/portsmouth-site-description</ref>]]

==Methodology==

[[File:diffuser.PNG|400px|thumb|right|Figure 2. Cross sectional diagram of the diffuser, showing the low and high pressure areas as well as the high pressure feed stream, enriched and depleted flows.<ref>Global Security (September 21, 2016). ''Gaseous Diffusion Uranium Enrichment'' [Online]. Available: http://www.globalsecurity.org/wmd/intro/u-gaseous.htm</ref>]]

Gaseous diffusion, like all [[uranium enrichment]] processes, utilizes the difference in [[mass]] between the 235U isotope and the 238U isotope. Because 238U possesses three more [[neutron]]s in its [[nucleus]] compared to 235U, it has a higher mass. The gaseous diffusion process is therefore based on the fact that, in a mixture of two gases, on average the lighter [[molecule]]s travel faster than the heavier ones. <ref name="r1"/> Due to this observation, if the gases are contained within a container, the lighter molecules will come into contact with the walls of the container more frequently. If the walls of the container were to be made of a semipermeable membrane, such that individual gas molecules could pass through but not enough to create a mass-flow through, then more of the lighter molecules will pass through the container. <ref name="r1"/> The gas leaving the container is therefore slightly enriched in the lighter molecules and the gas that did not pass through the semipermeable membrane is depleted. Figure 2 shows a picture of a diffuser and its container, membrane and piping which is used in some gaseous diffusion plants.

==Gaseous diffusion process==
[[File:gdc.jpg|400px|framed|right|Figure 3. Diffusers set up in a cascade. Enriched uranium comes out of the upper pipes and is sent upward through the cascade while the depleted uranium comes out of the bottom pipes and is sent downward through the cascade.<ref>U.S. Department of Energy (September 21, 2016). ''The Manhattan Project'' [Online]. Available: https://www.osti.gov/opennet/manhattan-project-history/Events/1942-1944_ur/k-25_working.htm</ref>]]

The gaseous diffusion process utilizes [[uranium hexafluoride]], UF6, because although it is a [[solid]] at room [[temperature]] it is easily vaporized. <ref name="r1"/> UF6 is not only convenient for its volatility, but also due to the fact that fluorine only consists of the isotope 19F, meaning the difference in molecular weights for UF6 are purely reliant on 235U and 238U.<ref name="r1"/> Here arises another problem however, for the masses of the two uranium isotopes are so nearly equal there is very little separation of 235UF6 and 238UF6 with one pass through a diffuser.<ref name="r1"/> Therefore a [[cascade process]] is needed to obtain any measurable amount of enrichment. Figure 3 on the right depicts diffusers set up in a cascade. The feed stream at diffuser 1 is the UF6 prior to enrichment (meaning it will contain 0.711% 235U and 99.289% 238U) and marks the start of the cascade. There will be hundreds to thousands of diffusers on the upward or enriching side as well as on the downward or depleted side. The slightly enriched UF6 is sent up the cascade process to the next diffuser where it will be enriched again. The slightly depleted UF6 will be sent downward through the cascade where it will also be enriched again. In this way, the enriched uranium keeps getting enriched and sent onward, and the depleated uranium also gets enriched and sent onward. The depleated uranium always gets sent downward where it will eventually be ejected from the downward stream as depleated uranium.

==References==
{{reflist}}