Pt. 110, App. J 10 CFR Ch. I (1–1–01 Edition)
by separation of the uranium, plutonium, (iii) A maximum width of 3 inches (7.62 cm) and fission products by solvent extraction for either a slab or annular vessel. using a mixture of tributyl phosphate in an (5) Plutonium nitrate to plutonium oxide organic diluent. conversion systems. Complete systems espe- Purex facilities have process functions cially designed or prepared for the conver- similar to each other, including: irradiated sion of plutonium nitrate to plutonium fuel element chopping, fuel dissolution, sol- oxide, in particular adapted so as to avoid vent extraction, and process liquor storage. criticality and radiation effects and to mini- There may also be equipment for thermal mize toxicity hazards. denitration of uranium nitrate, conversion of (6) Plutonium metal production systems. plutonium nitrate to oxide metal, and treat- Complete systems especially designed or pre- ment of fission product waste liquor to a pared for the production of plutonium metal, form suitable for long term storage or dis- in particular adapted so as to avoid criti- posal. However, the specific type and con- cality and radiation effects and to minimize figuration of the equipment performing toxicity hazards. these functions may differ between Purex fa- (7) Process control instrumentation spe- cilities for several reasons, including the cially designed or prepared for monitoring or type and quantity of irradiated nuclear fuel controlling the processing of material in a to be reprocessed and the intended disposi- reprocessing plant. tion of the recovered materials, and the safe- [55 FR 30451, July 26, 1990, as amended at 58 ty and maintenance philosophy incorporated FR 13005, Mar. 9, 1993. Redesignated at 61 FR into the design of the facility. A plant of the 35603, July 8, 1996] reprocessing of irradiated fuel elements, in- cludes the equipment and components which APPENDIX J TO PART 110—ILLUSTRATIVE normally come in direct contact with and di- rectly control the irradiated fuel and the LIST OF URANIUM CONVERSION major nuclear material and fission product PLANT EQUIPMENT AND PLUTONIUM processing streams. CONVERSION PLANT EQUIPMENT (1) Fuel element chopping machines, i.e., UNDER NRC EXPORT LICENSING AU- remotely operated equipment specially de- THORITY signed or prepared to cut, chop, or shear ir- radiated nuclear reactor fuel assemblies, NOTE—Uranium conversion plants and sys- bundles, or rods. tems may perform one or more trans- (2) Critically safe tanks, i.e., small diame- formations from one uranium chemical spe- ter, annular or slab tanks specially designed cies to another, including: conversion of ura- or prepared for the dissolution of irradiated nium ore concentrates to UO3, conversion of nuclear reactor fuel. UO3 to UO2, conversion of uranium oxides to (3) Solvent extraction equipment. UF4 or UF6, conversion of UF4 to UF6, con- Especially designed or prepared solvent ex- version of UF6 to UF4, conversion of UF4 to tractors such as packed or pulse columns, uranium metal, and conversion of uranium mixer settlers or centrifugal contactors for fluorides to UO2. Many key equipment items use in a plant for the reprocessing of irradi- for uranium conversion plants are common ated fuel. Because solvent extractors must to several segments of the chemical process be resistant to the corrosive effect of nitric industry, including furnaces, rotary kilns, acid, they are normally fabricated to ex- fluidized bed reactors, flame tower reactors, tremely high standards (including special liquid centrifuges, distillation columns and welding and inspection and quality assur- liquid-liquid extraction columns. However, ance and quality control techniques) out of few of the items are available ‘‘off-the- low carbon stainless steels, titanium, zir- shelf’’; most would be prepared according to conium or other high quality materials. customer requirements and specifications. (4) Chemical holding or storage vessels. Some require special design and construc- Especially designed or prepared holding or tion considerations to address the corrosive storage vessels for use in a plant for the re- properties of the chemicals handled (HF, F2, processing of irradiated fuel. Because hold- CLF3, and uranium fluorides). In all of the ing or storage vessels must be resistant to uranium conversion processes, equipment the corrosive effect of nitric acid, they are which individually is not especially designed normally fabricated of materials such as low or prepared for uranium conversion can be carbon stainless steels, titanium or zir- assembled into systems which are especially conium, or other high quality materials. designed or prepared for uranium conversion. Holding or storage vessels may be designed (a) Uranium Conversion Plant Equipment. for remote operation and maintenance and (1) Especially designed or prepared systems may have the following features for control for the conversion of uranium ore con- of nuclear criticality: centrates to UO3. (i) Walls or internal structures with a Conversion of uranium ore concentrates to boron equivalent of at least 2 percent, or UO3 can be performed by first dissolving the (ii) A maximum diameter of 7 inches (17.78 ore in nitric acid and extracting purified ura- cm) for cylindrical vessels, or nyl nitrate using a solvent such as tributyl
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phosphate. Next, the uranyl nitrate is con- tonium metal. Plutonium conversion plants verted to UO3 either by concentration and are usually associated with reprocessing fa- denitration or by neutralization with gas- cilities, but may also be associated with plu- eous ammonia to produce ammonium tonium fuel fabrication facilities. Many of diuranate with subsequent filtering, drying, the key equipment items for plutonium con- and calcining. version plants are common to several seg- (2) Especially designed or prepared systems ments of the chemical process industry. For for the conversion of UO3 to UF6. example, the types of equipment employed in Conversion of UO3 to UF6 can be performed these processes may include the following directly by fluorination. The process re- items: furnaces, rotary kilns, fluidized bed quires a source of fluorine gas or chlorine reactors, flame tower reactors, liquid cen- trifluoride. trifuges, distillation columns and liquid-liq- (3) Especially Designed or Prepared Sys- uid extraction columns. Hot cells, glove tems for the conversion of UO3 to UO2. boxes and remote manipulators may also be Conversion of UO3 to UO2 can be performed required. However, few of the items are through reduction of UO3 with cracked am- available off-the-shelf; most would be pre- monia gas or hydrogen. pared according to the requirements and (4) Especially Designed or Prepared Sys- specifications of the customer. Particular tems for the conversion of UO2 to UF4. care is essential in designing for the special Conversion of UO2 to UF4 can be performed radiological, toxicity and criticality hazards by reacting UO2 with hydrogen fluoride gas associated with plutonium. In some cir- (HF) at 300–500°C. cumstances, special design and construction (5) Especially Designed or Prepared Sys- considerations are required to address the tems for the conversion of UF4 to UF6. corrosive properties of some of the chemicals Conversion of UF4 to UF6 is performed by handled (e.g., HF). Finally, it should be exothermic reaction with fluorine in a tower noted that, for all plutonium conversion reactor. UF6 is condensed from the hot efflu- processes, items of equipment which individ- ent gases by passing the effluent stream ually are not especially designed or prepared through a cold trap cooled to -10°C. The proc- for plutonium conversion can be assembled ess requires a source of fluorine gas. into systems that are especially designed or (6) Especially Designed or Prepared Sys- prepared for use in plutonium conversion. tems for the conversion of UF4 to U metal. (b) Plutonium Conversion Plant Equip- Conversion of UF4 to U metal is performed ment by reduction with magnesium (large batches) (1) Especially designed or prepared systems or calcium (small batches). The reaction is for the conversion of plutonium nitrate to carried out at temperatures above the melt- oxide. ing point of uranium (1130°C). The main functions involved in this proc- (7) Especially designed or prepared systems ess are: process feed storage and adjustment, for the conversion of UF6 to UO2. precipitation and solid/liquor separation, Conversion of UF6 to UO2 can be performed calcination, product handling, ventilation, by one of three processes. In the first, UF6 is waste management, and process control. The reduced and hydrolyzed to UO2 using hydro- process systems are particularly adapted so gen and steam. In the second, UF6 is as to avoid criticality and radiation effects hydrolyzed by solution in water, ammonia is and to minimize toxicity hazards. In most added to precipitate ammonium diuranate, reprocessing facilities, this process involves and the diuranate is reduced to UO2 with hy- the conversion of plutonium nitrate to pluto- drogen at 820°C. In the third process, gaseous nium dioxide. Other processes can involve UF6, CO2, and NH3 are combined in water, the precipitation of plutonium oxalate or precipitating ammonium uranyl carbonate. plutonium peroxide. The ammonium uranyl carbonate is com- (2) Especially designed or prepared systems bined with steam and hydrogen at 500–600°C for plutonium metal production. to yield UO2. UF6 to UO2 conversion is often This process usually involves the performed as the first stage of a fuel fabrica- fluorination of plutonium dioxide, normally tion plant. with highly corrosive hydrogen fluoride, to (8) Especially Designed or Prepared Sys- produce plutonium fluoride, which is subse- tems for the conversion of UF6 to UF4. Con- quently reduced using high purity calcium version of UF6 to UF4 is performed by reduc- metal to produce metallic plutonium and a tion with hydrogen. calcium fluoride slag. The main functions in- (9) Especially designed or prepared systems volved in this process are the following: for the conversion of UO2 to UCl4 as feed for fluorination (e.g., involving equipment fab- electromagnetic enrichment. ricated or lined with a precious metal), NOTE: Plutonium conversion plants and metal reduction (e.g., employing ceramic systems may perform one or more trans- crucibles), slag recovery, product handling, formations from one plutonium chemical ventilation, waste management and process species to another, including: conversion of control. The process systems are particu- plutonium nitrate to PuO2, conversion of larly adapted so as to avoid criticality and PuO2 to PuF4 and conversion of PuF4 to plu- radiation effects and to minimize toxicity 561
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hazards. Other processes include the C.1. Much of the key equipment for heavy fluorination of plutonium oxalate or pluto- water production plants using either the nium peroxide followed by reduction to water-hydrogen sulphide exchange process metal. (GS process) or the ammonia-hydrogen ex- change process are common to several seg- [61 FR 35606, July 8, 1996, as amended at 65 ments of the chemical and petroleum indus- FR 70291, Nov. 22, 2000] tries; particularly in small plants using the GS process. However, few items are available APPENDIX K TO PART 110—ILLUSTRATIVE ‘‘off-the-shelf.’’ Both processes require the LIST OF EQUIPMENT AND COMPO- handling of large quantities of flammable, NENTS UNDER NRC EXPORT LICENS- corrosive and toxic fluids at elevated pres- ING AUTHORITY FOR USE IN A PLANT sures. Thus, in establishing the design and FOR THE PRODUCTION OF HEAVY operating standards for plants and equip- WATER, DEUTERIUM AND DEUTERIUM ment using these processes, careful attention COMPOUNDS to materials selection and specifications is required to ensure long service life with high NOTE: Heavy water can be produced by a safety and reliability factors. The choice is variety of processes. However, two processes primarily a function of economics and need. have proven to be commercially viable: the Most equipment, therefore, is prepared to water-hydrogen sulphide exchange process customer requirements. (GS process) and the ammonia-hydrogen ex- In both processes, equipment which indi- change process. vidually is not especially designed or pre- A. The water-hydrogen sulphide exchange pared for heavy water production can be as- process (GS process) is based upon the ex- sembled into especially designed or prepared change of hydrogen and deuterium between systems for producing heavy water. Exam- water and hydrogen sulphide within a series ples of such systems are the catalyst produc- of towers which are operated with the top tion system used in the ammonia-hydrogen section cold and the bottom section hot. exchange process and the water distillation Water flows down the towers while the hy- systems used for the final concentration of drogen sulphide gas circulates from the bot- heavy water to reactor-grade in either proc- tom to the top of the towers. A series of per- ess. forated trays are used to promote mixing be- C.2. Equipment especially designed or pre- tween the gas and the water. Deuterium mi- pared for the production of heavy water uti- grates to the water at low temperatures and lizing either the water-hydrogen sulphide ex- to the hydrogen sulphide at high tempera- change process or the ammonia-hydrogen ex- tures. Gas or water, enriched in deuterium, change process: is removed from the first stage towers at the junction of the hot and cold sections and the (i) Water-hydrogen Sulphide Exchange process is repeated in subsequent stage tow- Towers ers. The product of the last stage, water en- Exchange towers fabricated from carbon riched up to 30 percent in deuterium, is sent steel (such as ASTM A516) with diameters of to a distillation unit to produce reactor 6 m (20 ft) to 9 m (30 ft), capable of operating grade heavy water; i.e., 99.75 percent deute- at pressures greater than or equal to 2 MPa rium oxide. (300 psi) and with a corrosion allowance of B. The ammonia-hydrogen exchange proc- ess can extract deuterium from synthesis gas 6mm or greater. through contact with liquid ammonia in the (ii) Blowers and Compressors presence of a catalyst. The systhesis gas is fed into exchange towers and then to an am- Single stage, low head (i.e., 0.2 MPa or 30 monia converter. Inside the towers the gas psi) centrifugal blowers or compressors for flows from the bottom to the top while the hydrogen-sulphide gas circulation (i.e., gas liquid ammonia flows from the top to the containing more than 70 percent H2 S). The bottom. The deuterium is stripped from the blowers or compressors have a throughput hydrogen in the systhesis gas and con- capacity greater than or equal to 56 m3/sec- centrated in the ammonia. The ammonia ond (120,000 SCFM) while operating at pres- then flows into an ammonia cracker at the sures greater than or equal to 1.8 MPa (260 bottom of the tower while the gas flows into psi) suction and have seals designed for wet an ammonia converter at the top. Further H2 S service. enrichment takes place in subsequent stages (iii) Ammonia-Hydrogen Exchange Towers and reactor-grade heavy water is produced through final distillation. The synthesis gas Ammonia-hydrogen exchange towers great- feed can be provided by an ammonia plant er than or equal to 35 m (114.3 ft) in height that can be constructed in association with a with diameters of 1.5 m (4.9 ft) to 2.5 m (8.2 heavy water ammonia-hydrogen exchange ft) capable of operating at pressures greater plant. The ammonia-hydrogen exchange than 15 MPa (2225 psi). The towers have at process can also use ordinary water as a feed least one flanged, axial opening of the same source of deuterium. diameter as the cylindrical part through
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