2017 Water Reactor Fuel Performance Meeting September 10 (Sun) ~ 14 (Thu), 2017 Ramada Plaza Jeju Jeju Island, Korea

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1 RENEWAL OF URANUM SCRAP RECOVERY FACILITES AND CAPABILITIES AT AREVA NP - RICHLAND Clifford Yeager, PE AREVA Inc., Richland Site, 2101 Horn Rapids Rd, Richland WA cliff.yeager@areva.com ABSTRACT: Processes for recovery of uranium from scrap materials of various forms have been developed over the last 40+ years at the Richland nuclear fuel manufacturing plant. In the fuel fabrication process, enriched uranium is chemically processed into nuclear fuel pellets, which are loaded into rods, and thence into nuclear fuel assemblies. Scrap uranium materials are collected throughout these manufacturing processes. A high degree of recovery and recycle is necessary for economic and environmental reasons. The scrap recovery processes have been improved and now perform at very high levels of uranium purification and recovery efficiency. Treatment of liquid effluents has also been optimized for environmental performance. However, aging equipment and facilities have compromised system operability. It has also become difficult to meet modern industrial health and safety standards in these facilities. In 2015, a $15M project to renew both equipment and facilities was launched and will be completed in A new building will house state of the art processes to handle lower grade materials (typically <80% U) which require solvent extraction purification. The project will also upgrade the existing ADU (ammonium diuranate) line. The new dirty scrap facility will be able to process more than 25 metric ton uranium per year (MTU/yr. This provides capacity to process uranium-bearing scrap material for beneficial recovery of the uranium for external customers. Alternatively, AREVA NP offers expert engineering consultation and/or technology transfer services to assist customers in processing their scrap materials at their own sites. Highly effective uranium scrap recovery is a necessity in today s nuclear fuel processing for both economic and environmental reasons. KEYWORDS: Uranium, recovery, scrap, chemical processing I. INTRODUCTION TO THE RICHLAND FUEL FABRICATION PLANT The history of AREVA NP s nuclear fuel plant in Richland, Washington began in 1969 with Standard Oil of New Jersey, and what became known as the Exxon Nuclear Facility. It s location in the northwest part of the United States was due to proximity to the Hanford nuclear reservation, and specifically the Pacific Northwest National Laboratories. Over the years it grew and developed until today it has 1200 MTU/yr UF 6 to UO 2 conversion capacity and 800 MTU/yr of pelletizing and fuel assembly capacity. It is now part of AREVA NP s Fuel Business Unit, which includes sister plants in Romans, France and Lingen, Germany. Nuclear fuel fabricated at the facility, with a variety of PWR and BWR designs, has been sold all over the world; the product is made utilizing world class nuclear fuel processing equipment and facilities. Major investments in the Conversion, Pelletizing, Rod Fabrication and Bundle Assembly shops have resulted in a state-of-the-art fuel fabrication capability in Richland. 1

2 Figure 1: Richland Fuel Fabrication Facility primary activities Throughout the fuel fabrication process, scrap uranium is generated via routine production overage, from off-spec product, and from spills and other mishaps. This uranium, typically with a 3 to 5% enrichment, has high value; uranium recovery processes have been implemented for recovering and recycling this material. Due to their efficiency, uranium losses at Richland are <0.1% of plant throughput. 2

3 2. URANIUM SCRAP RECOVERY AT THE RICHLAND PLANT Figure 2: Scrap materials come in range of forms and compositions Uranium scrap material characteristics vary widely, from high grade scrap such as UO 2 pellets which are essentially pure UO 2 to incinerator ash, which is burned trash and has a uranium content of a few wt% U. Obviously, a single process with one set of equipment cannot be used. Over the years, processes and equipment used to implement them have been developed and refined, optimized for the specific type of scrap materials to be treated. Due to the variety of feed materials, quite a range of processes and equipment are being used. The Richland uranium recovery facilities have been also used for processing of scrap from external customers. With proper care, this can be good business for Richland and provide a real benefit to these customers. On the negative side, processing scrap materials can be surprising! A case with safety implications occurred when a scrap powder was processed which contained some unanalyzed organic material. When fed into the nitric acid dissolver, the material foamed up and onto the floor. It was necessary to burn-out the organic in a furnace; after that the material was processed successfully. The key lesson is that is important to characterize the material to the extent possible before processing uranium assay is essential but not sufficient! To be useful for efficient uranium recovery, the scrap recovery processes were developed and optimized to achieve: High standards of chemical, industrial, radiological and criticality safety. The constraints of the latter are rather unique to processing of enriched uranium scrap. Highly effective at removal of impurities, and proper conditioning of the uranium product, as the latter is recycled into extremely high quality nuclear fuel pellets. Good economy: the recycle costs must be kept as low as possible to make the recovery effort viable. Environmentally sound, as the processes generate gaseous, liquid, and solid effluents which must meet stringent discharge limits, economically. 3

4 Figure 3: General Scrap Processing diagram Generally, the wet scrap processes follow the same sequence. Different equipment is employed to handle specific materials and will be discussed later. Please refer to Figure 3. Typically, the first step is to solubilize the uranium using nitric acid. This operation can range from dissolution of high grade scrap to basically leaching of uranium from low grade. The goal is to optimize the ratio of uranium dissolved to that of undesirable elements, with as high as possible uranium recovery. The next step is solid-liquid separation to separate the uranyl nitrate (UN) solution from insoluble residues. Depending on the material processed, the equipment employed can range from simple sock filters to complicated rotary vacuum drum filters. The goal is to remove insoluble residue while minimizing uranium losses to the solid waste. The next step is treating the impure UN to remove the soluble impurities, such as rare earths and other dissolved metals. In Richland we use solvent extraction (basically a simplified PUREX process), achieving decontamination factors of up to 100,000. The resulting purified UN solution is recycled into UO 2 pellets via our ammonium diuranate (ADU) process. The waste stream from the solvent extraction (SX) process is treated to precipitate metals (including hazardous metals like lead), which are then filtered, packaged, and disposed of as solid waste. Achieving all of the above requirements using these processes to recover uranium from what is essentially trash is not easy! Type of Scrap U Content Recycle Method Insolubles Soluble Recycle Clean UO 2 88% U Oxidation then blend n/a n/a Dry Gadolinium Scrap >80% U Continuous in nitric acid Simple Filter Solvent Extraction ADU Dirty Powder 40-88% U Batch or continuous dissolution Drum filter Solvent Extraction ADU Incinerator Ash 5-20% U Batch dissolution Drum filter (large) Solvent Extraction ADU Table 1: Typical materials and processes used in Richland 4

5 Table 1 shows a few of the scrap materials that are routinely generated and processed in day to day operations at Richland. Where possible, clean scrap material is oxidized to U3O8 and added back directly into the pelletizing feed blends. Scrap containing gadolinium may be recycled dry in the Gd shop, but if recovery of the uranium is desired it must be processed through SX to achieve the Gd limit of <1 ppm in the recovered U. Since it is rather clean, simple filtration is used to remove the small quantity of insoluble solids. What we call dirty powder is heavily contaminated uranium oxide powder, which requires the more sophisticated RVDF for effective insoluble solids removal. At the bottom of the spectrum is incinerator ash, leaching of which generally results in dilute UN (10 s of grams/liter) with high insoluble solids loads, for which another, larger RVDF is used. The solids listed in the table are representative of the materials for which processes were developed and refined in Richland over the last forty five years, Although optimized for our own scrap materials, both equipment and chemical flowsheets can be adjusted by our experienced engineering staff to handle variations in material composition. A key part of the uranium recovery capability is disposal of gaseous, liquid and solid effluents. We are fortunate to have stringent, but non-zero limits in each of these areas. Richland has an excellent relationship with all of our regulators, based on a history of good environmental performance and transparency. In fact, the limits are high enough to allow us to process our own scrap plus have some capacity for external customers. 3. DESCRIPTION OF RENEWED CAPABILITIES FOR URANIUM RECOVERY As you can imagine, many years of processing in a nitric acid environment is very hard on equipment and facilities. Although process performance is excellent, equipment reliability compromises operations on a daily basis. Further, augmented modern health and safety standards have become difficult to meet in equipment designed 20+ years ago. Hence the need for the investment in the new facility, which we call SURF (Scrap Uranium Recovery Facility). This $15M project was launched at the end of 2015, and will be completed at the end of Refer to the building diagram in Figure 4. Figure 4: Isometric cutaway view of SURF building 5

6 The SURF provides a significant improvement in operational efficiency. This purpose-built facility will maintain the same process design and throughputs, but will offer more capacity through improved equipment reliability. It will also provide state-of-the-art ventilation and containment for improved radiological and chemical safety. It is not large, with a foot print of just 20m x 30m and 15m high, but it is a major improvement over the organically grown existing facility, which was a gradually converted engineering laboratory. More improvement will be gained with application of modern I&C technology. 4. SERVICES OFFERED TO EXTERNAL CUSTOMERS And so, the Richland Scrap Shop is open for business for customers with enriched uranium scrap materials which they either cannot or choose not to process themselves. As mentioned before, good characterization of the scrap material is important. Richland can assist the customer in analyzing material samples if necessary, as well as lab/pilot testing if needed for very unfamiliar materials. Typical contracts are for some tons per year, with price dependent on quantity and quality of the material. Again, good characterization of the material is important to the success of all. Typically, the uranium oxide product is not returned to the customer, but rather the customer s uranium account is credited with equivalent feed and SWU credits. There Is also no need to return any of the waste effluents to the customer, as our regulators allow us to dispose of the waste as our own, assuming certain constraints are met (primarily Beneficial Recovery, see below). In some cases, the customer s regulations may require return of solids residues, which can typically be accommodated. The Beneficial Recovery rule basically dictates that the cost of uranium recovery cannot exceed the value of the uranium recovered. This rule devolves from the fact that Richland is not allowed to process waste materials we are licensed only for uranium recovery. Customer cost savings due to avoidance of disposal costs are not included in this calculation. Thus typically very low grade or difficult scrap materials fail the beneficial recovery test, particularly in this time of depressed uranium prices. Economical aspects shall then be discussed between customer and AREVA NP. For such cases, Richland can offer a number of means to help the customer solve his scrap problems. The most comprehensive solution is a Technology Transfer project: experienced Richland engineers will work with the customer to define his needs, and then will offer design, fabrication, installation and startup as needed of scrap recovery capabilities on the customer site. Another related option is to provide consulting services as engineering and/or feasibility studies, providing expert advice on scrap processing options, process selection, licensing, safety analysis, equipment and facility design, etc. 5. CONCLUSION In conclusion, AREVA NP has recognized the value of the uranium recovery capability and expertise at Richland by investing in renewed processing capability. The SURF facility provides practical state of the art equipment and facilities for recovery of uranium from scrap materials produced both internally and by our customers. Health and safety aspects of these renewed capabilities will meet or exceed all modern standards. Effluents are treated to efficiently meet all environmental requirements. We offer customers a significant benefit in reduction of scrap material stockpiles, converting that liability into value for the customer. We can also use our expertise to help solve customer problems via technology transfers and/or consulting services. 6