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Cnc Milling Machine Conversion

August 30th, 2010

Cnc Milling Machine Conversion

Fernald Feed Materials Production Center РChina CNC Machining Parts РSheet Metal cabinet Manufactu   by jekky

History In 1948 the Atomic Energy Commission predecessor to the U S Department of Energy established large scale integrated facility for the production of fabricated uranium fuel cores by chemical and metallurgical techniques The plant was known as the Feed Materials Production Center since the uranium fuel cores it produced were the eed for the AEC plutonium production reactors These nuclear reactors were located at Oak Ridge in Tennessee the Savannah River Site in South Carolina and at Hanford in the state of Washington The uranium metal produced was in the form of derbies ingots billets and fuel cores The FMPC also served as the country central repository for another radioactive metal Thorium The plant was located in the rural town of Fernald which is about 20 miles northwest of Cincinnati Ohio and occupies 1 050 acres This location was chosen because it was between the uranium ore delivery ports of New York and New Orleans and it was accessible to the other main AEC sites In addition the site was close to Cincinnati large labor force the landscape was level making the site construction easy it was isolated which provided safety and security and it was located 30 to 50 feet above a large water aquifer which supplied the water needed for uranium metal processing From 1951 to 1989 Fernald converted uranium ore into metal and then fabricated this metal into target elements for nuclear reactors Annual production rates ranged from a high in 1960 of 10 000 metric tons to a low in 1975 of 1 230 metric tons 2 Refining uranium metal was a process requiring a series of chemical and metallurgical conversions that occurred in nine specialized plants at the site Releases from the Fernald site to the surrounding area resulting in exposure to community residents included ionizing radiation soluble and insoluble forms of uranium and various other hazardous chemicals The Centers for Disease Control and Prevention CDC has conducted a historical exposure characterization and developed dose estimation models through the Fernald Dose Reconstruction Project with an endpoint of developing an algorithm to estimate doses to individual persons who lived within the exposure assessment domain the area within a ten kilometer radius from the center of the plant site In addition to radioactive materials many other non radiological toxic substances were present in the production area as materials by products or products Workers were exposed to chlorinated and non chlorinated solvents metals and metal salts and nuisance dusts 3 10 Community residents may have been exposed to these substances through ground water pathways soil contamination and air dispersion of emissions from the site Two separate medical surveillance programs for former workers and community residents have been funded by settlements of class action litigation against National Lead of Ohio a contractor for the DOE These Fernald Settlement Funds are administered by the US Federal Court which maintains oversight of the Fernald Medical Monitoring Programs The Fernald Residents Medical Monitoring Program FMMP is a voluntary ongoing medical surveillance program for community residents living within five miles of the perimeter of the Fernald site and the Fernald Workers Medical Monitoring Program FWMMP is a program for former workers who were employed when National Lead of Ohio was the contractor Activities of the medical monitoring programs include both periodic medical examinations and diagnostic testing and yearly questionnaire data collection As of January 1 2007 there were 9764 persons enrolled in the FMMP and 2716 former workers enrolled in the FWMMP The FMMP has an extensive computer database available for research studies Samples of whole blood serum plasma and urine were obtained from all FMMP participants at the time of the initial examination and over 100 000 one ml aliquots of these biospecimens have been stored at minus 80o C since then For more information about the Fernald Medical Monitoring Program see their website Production facilities The neutrality of this article is disputed Please see the discussion on the talk page Please do not remove this message until the dispute is resolved April 2008 Plant 1 The production process at the Fernald Feed Materials Production Center begins at Plant 1 also known as the Sampling Plant The principal function of the Sampling Plant was to obtain representative samples of the large quantities of incoming ore concentrates 11 This plant was divided into two main processing lines one for Q 11 and one for INX Q 11 was the term used to refer to radium bearing ores primarily mined in the Belgian Congo while INX was a non radium concentrate The problem with handling radium bearing ores12 was that one of radium daughter particles is Radon a colorless odorless and tasteless radioactive gas that is known to cause lung cancer Q 11 was received in 55 gallon drums The drums were deheaded prior to processing and were conveyed through a thawing tunnel which also provided surge capacity of deheaded drums The drums were lifted to the top of the building by a skip hoist where they were emptied into a surge hopper that feeds the magnetic separator and jaw crusher From the jaw crusher the one half inch material passes through a rotary drum dryer to a system of conveyors which conveys the material to a surge hopper that feeds the ring roll mill The particle size output from the mill was controlled to about 100 mesh by an air classifier mounted directly on the mill The undersized material was blown to a cyclone separator that was mounted directly above the first Gallagher sampler The three Gallagher samplers in series each took a 10 cut of the stream fed to it producing a sample approximately 0 1 of the original lot size The main stream was conveyed to a drumming station where it was packaged in 55 gallon or 30 gallon drums for use in the Refinery The official weight was taken at this point 13 The INX line was similar to the Q 11 line except that the thawing tunnel has been omitted and a hammer mill and bucket elevator replaces the jaw crusher rotary dryer ring roll mill air classifier and cyclone separator In addition to sampling incoming ores this Plant reconditions 30 and 55 gallon drums which are used to transport and store radioactive materials onsite It also contains a safe geometry digestion system used to process enriched uranium materials assaying up to 5 235U This digester was so named because the piping was of such a diameter and distance between pipes making a criticality incident nigh impossible 14 Plant 2 3 Plant 2 3 was known as the Ore Refinery Denitration Plant It was called Plant 2 3 because two separate functions occur in the same building Here uranium values were recovered from feed materials i e ores concentrates and residues and were converted to concentrated uranium trioxide also called orange salt In addition to uranium the Refinery was capable of extracting and purifying a number of different materials 14 The Ore Refinery consists of three major process areas designated digestion15 Plant 2 extraction16 and denitration17 Plant 3 Support areas include nitric acid recovery raffinate treatment18 and refinery sump 19 The digestion extraction and raffinate areas included hot and cold sides To provide radiation protection from the radium bearing Q 11 ore the hot material concrete shielding was provided around appropriate process equipment and the hot side of each area was enclosed by concrete walls 20 The principal function of Plant 2 3 was uranium purification and conversion of uranium bearing materials into uranium trioxide UO3 or orange oxide There are three principal forms of uranium residues each having a separate processing route for putting the uranium into solution Uranium oxides are dissolved in 6000 gallon vats of pure nitric acid in the Oxide Digester also known as the west metal dissolver miscellaneous residues which required filtration were dissolved in the Slag Leach Digester21 and metals were dissolved in the Metal Dissolver If the ore was poured too rapidly into the nitric acid vats a condition known as a oilover results The acid literally generates so much gas that it becomes a foam and oils over the sides of the vat just like dropping Alka Seltzer into a glass of water Many workers were told to not step in any puddles on the floor as they were probably nitric acid left from one of these oilover incidents The site employed their own Cobblers just to repair work boots that had been exposed to too much acid Another hazard was the Nitrous Oxide fumes coming off the nitric acid vats There were so many fumes that on high humidity days during the Summer there appeared to be an orange cloud encasing this building and anyone just walking past would experience a sensation as if he had wandered into a swarm of bees the fumes bonding with the water droplets from the humidity made a dilute nitric acid The resulting UNH Uranium Nitrate Hexahydrate material pumped out of the vats was then processed through extraction to purify the solution The UNH solution was passed through a multi stage liquid liquid counter current tower with TBP tri butyl phosphate and kerosene to extract the uranyl nitrate The impurities exit the tower as the raffinate stream for further processing The extract solution was passed through another counter current extraction tower to re extract the uranyl nitrate from the organic into deionized water The organic was then processed through a wash to be recycled back through the extraction process The resulting UNH solution was in a pure form for further concentrating and thermal denitration to UO3 named Orange Oxide by the plant workers because of its physical resemblance to a powdered orange drink mix The UNH solution was concentrated through a process known as Boildown In this process heat was applied to the solution from steam coils inside the boildown tanks As the boiling point of the solution was obtained the water was removed through evaporation thus concentrating the solution The solution was concentrated from 90 grams uranium per liter to 1300 grams uranium per liter in two stages The concentrated solution now in 250 gallon batches was further heated in a process known as Pot Denitration to thermally denitrate the UNH to UO3 The UO3 material was then pneumatically removed from the denitration pots and packaged out in hoppers with a capacity of 3 6 metric tons or 55 gallon drums This pneumatic transfer of the product was known as Gulping 22 23 Plant 4 The Green Salt Plant the common name for Plant 4 produced green salt UF4 from UO3 Green salt was the key intermediate compound in the overall process of producing uranium metal 24 This plant contains 12 banks of furnaces for the conversion of uranium trioxide orange oxide to uranium tetrafluoride green salt Each bank consists of four furnaces in series The first furnace was constructed of stainless steel for the hydrogen reduction of orange oxide to uranium dioxide aka brown oxide or cocoa by the reaction UO3 H2 UO2 H2O The UO2 was then fed directly to the first of the next three furnaces in series These furnaces were constructed of Inconel for the hydrofluorination of brown oxide to green salt 2 The reaction was UO2 4HF UF4 2H2O Orange oxide was received from the Refinery in five ton mobile hoppers which were mounted on seal hoppers to feed the reduction furnace at a rate of approximately 375 pounds per hour for producing metal grade UF4 The powder was agitated and carried through the reduction furnace by a ribbon flight screw Dissociated ammonia was metered to the reduction reactors and passed counter currently to the bed of uranium oxide within the reactor Note these were chemical reactors not nuclear reactors The off gases from the reduction reactors were passed to a hydrogen burner where the excess hydrogen was burned and then passed through a dust collector to remove any entrained brown oxide UO2 that might have been present The brown oxide in the reduction furnace passed through a seal hopper and a feed screw to the first of the three hydrofluorination furnaces The bed of brown oxide was moved through the hydrofluorination furnace by ribbon flight screws and contacted counter currently by hydrofluoric acid vapors The UF4 was removed from the third furnace and conveyed to a packaging station where the product was packaged in 10 gallon pails for use in the Metal Plant or in 5 ton containers for shipment to the cascades The off gases containing water vapor formed in the reaction and excess hydrofluoric acid was removed from the first furnace and were sent to hydrofluoric acid recovery The gases first passed to a partial condenser that removed all of the water in the form of 70 aqueous hydrofluoric acid The remainder of the gases was then passed to a total condenser which condenses the remainder of the acid as anhydrous hydrofluoric acid The gases at this point contain only the nitrogen from seals and purge gases and small amounts of hydrofluoric acid that did not condense in the total condenser These were passed through potassium hydroxide scrubbers to remove the last traces of acid and then discharged to the atmosphere 2 25 26 Plant 5 Plant 5 the Metals Production Plant main process equipment consisted of eleven jolters five filling machines forty four reduction furnaces two breakout stations in the Reduction Area and twenty eight vacuum casting furnaces in the Recast Area 20 27 The conversion of UF4 to massive metal was accomplished by the thermite reduction of green salt with magnesium in a refractory lined steel reaction vessel or bomb Four hundred and fifty pounds of green salt were blended with approximately 72 pounds of magnesium The resulting mixture was uniformly packed into the reduction bomb which has previously been lined with refractory slag in a jolting apparatus Following these steps the bomb was capped with refractory sealed and placed in one of 49 electric m

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