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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Bismuth phosphate process | 2/2 | https://en.wikipedia.org/wiki/Bismuth_phosphate_process | reference | science, encyclopedia | 2026-05-05T13:04:37.315754+00:00 | kb-cron |
The bismuth phosphate process involved taking the irradiated uranium fuel slugs and removing their aluminium cladding. Because there were highly radioactive fission products inside, this had to be done remotely behind a thick concrete barrier. This was done in the "Canyons" (B and T buildings) at Hanford. The slugs were dumped into a dissolver, covered with sodium nitrate solution and brought to a boil, followed by slow addition of sodium hydroxide. After removing the waste and washing the slugs, three portions of nitric acid were used to dissolve the slugs. The second step was to separate the plutonium from the uranium and the fission products. Bismuth nitrate and phosphoric acid were added, producing bismuth phosphate, which was precipitated carrying the plutonium with it. This was very similar to the lanthanum fluoride process, in which lanthanum fluoride was used as the carrier. The precipitate was removed from the solution with a centrifuge and the liquid discharged as waste. Getting rid of the fission products reduced the gamma radiation by 90 percent. The precipitate was a plutonium-containing cake which was placed in another tank and dissolved in nitric acid. Sodium bismuthate or potassium permanganate was added to oxidize the plutonium. Plutonium would be carried by the bismuth phosphate in the tetravalent state but not in the hexavalent state. The bismuth phosphate would then be precipitated as a by product, leaving the plutonium behind in solution. This step was then repeated in the third step. The plutonium was reduced again by adding ferrous ammonium sulfate. Bismuth nitrate and phosphoric acid were added and bismuth phosphate precipitated. It was dissolved in nitric acid and the bismuth phosphate was precipitated. This step resulted in reducing the gamma radiation by four more orders of magnitude, so the plutonium-bearing solution now had 100,000-th of the original gamma radiation. The plutonium solution was transferred from the 221 buildings to the 224 buildings, through underground pipes. In the fourth step, phosphoric acid was added and the bismuth phosphate precipitated and removed; potassium permanganate was added to oxidize the plutonium. In the "crossover" step, the lanthanum fluoride process was used. Lanthanum salts and hydrogen fluoride were added again and lanthanum fluoride was precipitated, while hexavalent plutonium was left in solution. This removed lanthanides like cerium, strontium [sic] and lanthanum, that bismuth phosphate could not. The plutonium was again reduced with oxalic acid and the lanthanum fluoride process was repeated. This time potassium hydroxide was added to metathesize the solution. Liquid was removed with a centrifuge and the solid dissolved in nitric acid to form plutonium nitrate. At this point, a 330-US-gallon (1,200 L) batch sent would have been concentrated to 8 US gallons (30 L). The final step was carried out at the 231-Z building, where hydrogen peroxide, sulfates and ammonium nitrate were added to the solution and the hexavalent plutonium was precipitated as plutonium peroxide. This was dissolved in nitric acid and put into shipping cans, which were boiled in hot air to produce a plutonium nitrate paste. Each can weighed about 1 kg and was shipped to the Los Alamos Laboratory. Shipments were made in a truck carrying twenty cans and the first arrived at Los Alamos on 2 February 1945. The plutonium was used in the Fat Man bomb design tested in the Trinity nuclear test on 16 July 1945, and in the bombing of Nagasaki on 9 August 1945.
== Decommissioning == In 1947, experiments began at Hanford on a new REDOX process using methyl isobutyl ketone (codenamed hexone) as the extractant, which was more efficient. Construction of a new REDOX plant commenced in 1949 and operations began in January 1952, the B plant closing that year. Improvements to the T plant resulted in a 30 percent increase in productivity and improvements were made to the B plant. There were plans to reactivate the B plant but the new PUREX plant that opened in January 1956 was so efficient that the T plant was closed in March 1956 and plans to reactivate the B plant were abandoned. By 1960, the PUREX plant's output had surpassed the combined output of the B and T plants and the REDOX plant.
== Notes ==
== References == Gerber, Michele (June 1996). Plutonium Production Story at the Hanford Site: Processes and Facilities History (PDF). Washington, D.C.: United States Department of Energy. doi:10.2172/664389. OCLC 68435718. OSTI 664389. HC-MR-0521. Retrieved 17 April 2017. Hanford Engineer Works Technical Manual (Report). Richland, Washington: Hanford Engineer Works. 1 May 1944. doi:10.2172/6892962. OSTI 6892962. Hewlett, Richard G.; Anderson, Oscar E. (1962). The New World, 1939–1946 (PDF). University Park, Pennsylvania: Pennsylvania State University Press. ISBN 0-520-07186-7. OCLC 637004643. Retrieved 26 March 2013. {{cite book}}: ISBN / Date incompatibility (help) Jones, Vincent (1985). Manhattan: The Army and the Atomic Bomb (PDF). Washington, D.C.: United States Army Center of Military History. OCLC 10913875. Archived from the original (PDF) on 4 February 2017. Retrieved 25 August 2013. Seaborg, Glenn T. (September 1981). The Plutonium Story. Lawrence Berkeley Laboratory, University of California. OCLC 4436007756. LBL-13492, DE82 004551. Retrieved 17 April 2017.