Editing Calutron (section)

== Operations ==
[[File:Beta calutron.jpg|thumb|alt=A long, rectangular-shaped structure|Beta racetrack. These second stage racetracks were smaller than the Alpha racetracks and contained fewer process bins. Note that the oval shape of the Alpha I racetrack has been abandoned for ease of servicing.]]
The Alpha racetracks were a 24-fold magnification of the XA calutron that could hold 96 calutron Alpha tanks. The calutrons were upright and arrayed facing each other in pairs of inner and outer machines. To minimize magnetic losses, and to economize on steel consumption, the assembly was curved into an oval shape that formed a closed magnetic loop {{convert|122|ft}} long, {{convert|77|ft}} wide and {{convert|15|ft}} high, in the shape of a racetrack; hence the name.<ref name="Lawrence and his Laboratory" /> The two Alpha I buildings, 9201-1 and 9201-2, each contained two racetracks, with only one in the Alpha I{{frac|1|2}}, 9201-3. The Beta racetracks were smaller, linear in shape, and optimized for recovery rather than production, with only 36 instead of 96 process bins. The four Alpha II racetracks were also linear in configuration. They incorporated many improvements, the most important being that they had four sources instead of just two.{{sfn|Manhattan District|1947e|pp=S5–S7}}{{sfn|Jones|1985|p=139}} They also had improved magnets and vacuum systems.{{sfn|Manhattan District|1947f|pp=S4–S7}}

Tennessee Eastman was hired to manage Y-12 on the usual cost plus fixed fee basis, with a fee of $22,500 per month plus $7,500 per racetrack for the first seven racetracks and $4,000 per additional racetrack. Workers were recruited in the Knoxville area. The typical recruit was a young woman, a recent graduate of a local high school. Training was initially conducted at the [[University of Tennessee]]. Training switched to Berkeley from April to September 1943, where it was conducted on the XA calutron and a 1:16 scale model of the Alpha racetrack, and then to Oak Ridge when the XAX calutron became available. Some 2,500 operators would be required once all the Alpha II calutrons were available. The Tennessee Eastman payroll at Y-12 ballooned from 10,000 in mid-1944 to 22,482 in August 1945. For security reasons, the trainees were not informed of the purpose of the equipment they were taught to operate.{{sfn|Jones|1985|pp=140–142}}{{sfn|Hewlett|Anderson|1962|p=143}}

[[File:Alpha II Calutron.jpg|thumb|left|alt=A long, rectangular-shaped structure|Alpha II racetrack. There were four of these.]]
The calutrons were initially operated by scientists from Berkeley to remove bugs and achieve a reasonable operating rate. Then the Tennessee Eastman operators took over. Nichols compared unit production data, and pointed out to Lawrence that the young "hillbilly" girl operators were outproducing his Ph.Ds. They agreed to a production race and Lawrence lost, a morale boost for the "[[Calutron Girls]]" (called Cubicle Operators at the time) and their supervisors. The women were trained like soldiers not to reason why, while "the scientists could not refrain from time-consuming investigation of the cause of even minor fluctuations of the dials".{{sfn|Nichols|1987|p=131}}

For a while, the calutrons suffered from a series of debilitating breakdowns and equipment failures, exacerbated by a shortage of spare parts. Hopes that the Alpha II racetracks would be more reliable soon faded, as they were plagued by insulator failures. These problems were gradually overcome. The first shipments of enriched uranium to the Manhattan Project's [[Los Alamos Laboratory]] were made in March 1944, consisting of Alpha product enriched to 13 to 15 percent uranium-235. While of no use in a bomb, it was urgently required for experiments with enriched uranium. The last shipment of Alpha product was made on 11 May 1944. On 7 June 1944, Y-12 made its first delivery of [[weapons-grade uranium|weapons-grade]] Beta product, enriched to as high as 89% uranium-235.{{sfn|Jones|1985|pp=140–142}}{{sfn|Manhattan District|1947f|pp=S4–S7, 4.5}}

[[File:Cumulative Shipments of U-235 from Y-12 to Los Alamos 1944-1946.png|thumb|right]]
A major problem was that of loss of feed material and product. Only 1 part in 5,825 of the feed material became finished product. About 90 percent was splattered over the feed bottles or vacuum tanks. The problem was particularly acute with the enriched feed of the Beta calutrons. Extraordinary efforts were made to recover product, including burning the carbon receiver liners to recover the uranium in them. Despite everything, some 17.4 percent of Alpha product and 5.4 percent of Beta product was lost. [[Frank Spedding]] from the Manhattan Project's [[Ames Laboratory]] and [[Philip Baxter]] from the British Mission were sent to advise on improvements to recovery methods.{{sfn|Jones|1985|pp=144–145}} The death of a worker from exposure to phosgene also prompted a search for a safer production process.{{sfn|Larson|2003|p=102}}

In February 1945, slightly enriched 1.4 percent uranium-235 feed material began arriving from the [[S-50 (Manhattan Project)|S-50 liquid thermal diffusion plant]]. Shipments of product from S-50 were discontinued in April. S-50 product was fed into K-25 instead.{{sfn|Manhattan District|1947f|p=4.11}} In March 1945, Y-12 began receiving feed enriched to 5 percent from K-25.{{sfn|Jones|1985|p=148}} The output of these plants was in the form of uranium hexafluoride ({{chem|U|F|6}}). It was converted to uranium trioxide, which then went into the usual process for conversion to uranium tetrachloride.{{sfn|Manhattan District|1947f|p=4.6}} On 5 August 1945, K-25 started producing feed enriched to 23 percent, enough to be fed straight into the Beta racetracks. The remaining Alpha product was then fed into K-25. By September 1945, the calutrons had produced 88 kilograms of product with an average enrichment of 84.5 percent, and the Beta racetracks turned out another 953 kilograms enriched to 95 percent by the end of the year.{{sfn|Jones|1985|p=148}} Enriched uranium from the calutrons provided the fissile component of the [[Little Boy]] atomic bomb used in the [[atomic bombing of Hiroshima]] in August 1945.<ref name="Lawrence and his Laboratory" />{{sfn|Jones|1985|p=536}}
{| class="wikitable" style="float:left; margin-top:0; margin-left:0em; margin-right:2em; line-height:10pt; width:30%;"
|+ style="margin-bottom: 5px;" | Manhattan Project – Electromagnetic project costs through 31 December 1946 {{sfn|Manhattan District|1947a|p=3.5}}
!scope="col"|Site
!scope="col"| Cost (1946 USD)
!scope="col"| Cost ({{Inflation-year|US}} USD)
!scope="col"| % of total
|-
| Construction
!scope="row" style="text-align:right;"| ${{Formatprice|303787176}}
!scope="row"  style="text-align:right;"| ${{Formatprice|{{Inflation|US|303787176|1946|r=2}}}}
!scope="row" style="text-align:right;"| {{percentage|303787176|572762083|1}}
|-
| Operations
!scope="row" style="text-align:right;"| ${{Formatprice|240200000}}
!scope="row" style="text-align:right;"| ${{Formatprice|{{Inflation|US|240200000|1946|r=2}}}}
!scope="row" style="text-align:right;"| {{percentage|240200000|572762083|1}}
|-
| Research
!scope="row" style="text-align:right;"| ${{Formatprice|19642325}}
!scope="row" style="text-align:right;"| ${{Formatprice|{{Inflation|US|19642325|1946|r=2}}}}
!scope="row" style="text-align:right;"| {{percentage|19642325|572762083|1}}
|-
| Design
!scope="row" style="text-align:right;"| ${{Formatprice|6628926}}
!scope="row" style="text-align:right;"| ${{Formatprice|{{Inflation|US|6628926|1946|r=2}}}}
!scope="row" style="text-align:right;"| {{percentage|6628926|572762083|1}}
|-
| Silver Program
!scope="row" style="text-align:right;"| ${{Formatprice|2482626}}
!scope="row" style="text-align:right;"| ${{Formatprice|{{Inflation|US|2482626|1946|r=2}}}}
!scope="row" style="text-align:right;"| {{percentage|2482626|572762083|1}}
|-
| '''Total'''
!scope="row" style="text-align:right;"| '''${{Formatprice|572762083}}'''
!scope="row" style="text-align:right;"| '''${{Formatprice|{{Inflation|US|572762083|1946|r=2}}}}'''
|}

With the war over, the Alpha tracks began to suspend operations on 4 September 1945, and ceased operation completely on 22 September. The last two Beta tracks went into full operation in November and December 1945, processing feed from K-25 and the new K-27 gaseous diffusion plant.{{sfn|Hewlett|Anderson|1962|pp=624–625}} By May 1946, studies suggested that the gaseous diffusion plants could fully enrich the uranium by themselves without accidentally creating a critical mass.{{sfn|Hewlett|Anderson|1962|p=630}} After a trial demonstrated that this was the case, Groves ordered all but one Beta track shut down in December 1946.{{sfn|Hewlett|Anderson|1962|p=646}}

The total cost of the electromagnetic project up to the end of the Manhattan Project on 31 December 1946 was ${{Formatprice|672762083}} (equivalent to ${{Formatprice|{{Inflation|US|672762083|1946|r=-1}}}} in {{Inflation-year|US}}).{{sfn|Manhattan District|1947a|p=3.5}}