ML12146A381
| ML12146A381 | |
| Person / Time | |
|---|---|
| Issue date: | 05/25/2012 |
| From: | NRC/OI, NRC/OIG |
| To: | |
| References | |
| Download: ML12146A381 (78) | |
Text
03/22/10 - slide 0 G-112 OI/OIG Reactor & Materials Overview Fuel Cycle Technology H R T D Human Resources Training & Development
03/22/10 - slide 1 G-112 OI/OIG Reactor & Materials Overview Fuel Cycle Technology Objectives:
Discuss an overview of the uranium fuel cycle Discuss uranium recovery and identify its associated hazards Discuss uranium conversion and identify its associated hazards
03/22/10 - slide 2 G-112 OI/OIG Reactor & Materials Overview Fuel Cycle Technology Discuss uranium enrichment and its associated hazards Discuss uranium fuel fabrication and its associated hazards Briefly discuss the mixed oxide (MOX) fuel fabrication program Briefly discuss the Blended Low-Enriched Uranium (BLEU) project
03/22/10 - slide 3 G-112 OI/OIG Reactor & Materials Overview Natural uranium consists of three isotopes:
Isotope % Abundance Half Life (years) 238U 99.284 4.5 billion 235U*
0.711 704 million 234U 0.005 245 thousand Properties of Natural Uranium
- Must be enriched up to about 3-5% for commercial fuel
03/22/10 - slide 4 G-112 OI/OIG Reactor & Materials Overview Fuel Cycle Flow Diagram
03/22/10 - slide 5 G-112 OI/OIG Reactor & Materials Overview Fuel Cycle Flow Diagram
03/22/10 - slide 6 G-112 OI/OIG Reactor & Materials Overview URANIUM RECOVERY OPERATIONS
03/22/10 - slide 7 G-112 OI/OIG Reactor & Materials Overview Regulated under 10 CFR Part 40 What is Regulated
- Uranium Milling - means any activity that results in the production of byproduct material as defined in this part
- In-Situ Leaching (ISL)
- Byproduct material (Uranium Tailings)
- Most uranium is imported (>80% of 32,000 tons of U3O8 used per year)
03/22/10 - slide 8 G-112 OI/OIG Reactor & Materials Overview Uranium Recovery Facilities
Uranium Recovery Sites Undergoing Decommissioning Note: Colorado, Texas, and Utah are agreement states Pathfinder Lucky Mc ANC Gas Hills Umetco Gas Hills Sweetwater (conventional mill standby)
Rio Algom (possible ISL restart)
Homestake Western Nuclear Split Rock Exxon Highland Union Pacific Bear Creek PRI SR-HUP (active ISL)
Cogema (possible ISL restart)
Pathfinder Shirley Basin Crow Butte (active ISL)
UNC Church Rock Sequoyah Fuels
03/22/10 - slide 10 G-112 OI/OIG Reactor & Materials Overview Uranium Ore Sand
03/22/10 - slide 11 G-112 OI/OIG Reactor & Materials Overview Steps in Uranium Recovery
03/22/10 - slide 12 G-112 OI/OIG Reactor & Materials Overview U Solvent Extraction Tanks at a Typical U Mill
03/22/10 - slide 13 G-112 OI/OIG Reactor & Materials Overview Typical U Open Pit Mine and Mill Facility
03/22/10 - slide 14 G-112 OI/OIG Reactor & Materials Overview In-Situ Leach Diagram
03/22/10 - slide 15 G-112 OI/OIG Reactor & Materials Overview ISL Well Field
03/22/10 - slide 16 G-112 OI/OIG Reactor & Materials Overview Injection Well Head
03/22/10 - slide 17 G-112 OI/OIG Reactor & Materials Overview ISL Production Facility
03/22/10 - slide 18 G-112 OI/OIG Reactor & Materials Overview Yellowcake packaged in 55-gallon Drums and prepared for shipment
03/22/10 - slide 19 G-112 OI/OIG Reactor & Materials Overview Ore dust and radon emissions from ore crushing, sorting, and storage Yellowcake dust from drying and packaging area Windblown particulates and radon emission from the U mill tailings disposal area Soluble uranium compounds attack the kidneys (10 CFR 20.1201 (e) - 10 mgs/week)
Radiological Hazards of U Recovery
03/22/10 - slide 20 G-112 OI/OIG Reactor & Materials Overview Uranium Recovery Hazards
03/22/10 - slide 21 G-112 OI/OIG Reactor & Materials Overview Uranium Conversion
03/22/10 - slide 22 G-112 OI/OIG Reactor & Materials Overview 10 CFR Part 40 - Domestic Licensing of Source Material Source material is uranium or thorium (in any combination), in any chemical or physical form, or ore containing > 0.05% of the above.
Honeywell (old Allied-Signal) at Metropolis IL - only operating US plant Sequoyah Fuels at Gore OK - decommissioned Regulation of U Conversion
03/22/10 - slide 23 G-112 OI/OIG Reactor & Materials Overview Honeywell U Conversion Plant
03/22/10 - slide 24 G-112 OI/OIG Reactor & Materials Overview Statue of Superman Metropolis, IL Courthouse
03/22/10 - slide 25 G-112 OI/OIG Reactor & Materials Overview Mills Concentrate ores from ~1% to ~60%
Yellowcake (U3O8-really a mix of UO2 and UO3)
Ammonium Diuranate (ADU - (NH4)2U2O7)
Conversion Output is UF6 Fluorine is used for two reasons:
Only one isotope Physical properties are commercially viable U Conversion
03/22/10 - slide 26 G-112 OI/OIG Reactor & Materials Overview UF6 product is 99.99% pure.
Packaged in 10 and 14 ton cylinders.
Allowed to cool for 5 days to solidify.
Overfill is the highest safety concern.
Product (source material) is shipped to the Gaseous Diffusion Plants for enrichment (special nuclear material).
U Conversion
03/22/10 - slide 27 G-112 OI/OIG Reactor & Materials Overview UF6 + 2H2O > UO2F2 + 4HF UF6 Properties When reacts with moisture in air, creates deadly hydrogen fluoride (HF)
Uranyl Fluoride Chemical Hazard
03/22/10 - slide 28 G-112 OI/OIG Reactor & Materials Overview HF Severely Damages Skin
03/22/10 - slide 29 G-112 OI/OIG Reactor & Materials Overview More HF Skin Damage
03/22/10 - slide 30 G-112 OI/OIG Reactor & Materials Overview Damage Largely Healed
03/22/10 - slide 31 G-112 OI/OIG Reactor & Materials Overview In January 1986, a Mark 48Y 14-ton cylinder was overfilled with liquid UF6.
The operators did not know by how much the weight limits were exceeded.
Product draw-off stopped due to solidification of the UF6 as it cooled.
A supervisor ordered the operator to place the cylinder in a steam chest for 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
About 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> into the heat-up, the cylinder failed catastrophically. One operator died.
Sequoyah Fuels Accident
03/22/10 - slide 32 G-112 OI/OIG Reactor & Materials Overview Sequoyah Fuels in 1986 Site of the accident
03/22/10 - slide 33 G-112 OI/OIG Reactor & Materials Overview UF6 Cylinder at Sequoyah Fuels
03/22/10 - slide 34 G-112 OI/OIG Reactor & Materials Overview Damaged Cylinder and Steam Chest
03/22/10 - slide 35 G-112 OI/OIG Reactor & Materials Overview Rags Stuffed in the Breach in the Cylinder
03/22/10 - slide 36 G-112 OI/OIG Reactor & Materials Overview Washing Out the Residual UF6
03/22/10 - slide 37 G-112 OI/OIG Reactor & Materials Overview Close-up View of the Breach in the Cylinder
03/22/10 - slide 38 G-112 OI/OIG Reactor & Materials Overview Accidental UF6 Release from Honeywell Occurred on December 22, 2003 Release of UF6 to offsite environment No injuries to workers Four members of public reported to the local hospital. One of these exhibited skin reddening and symptoms of low level exposure to HF
03/22/10 - slide 39 G-112 OI/OIG Reactor & Materials Overview Uranium Enrichment
03/22/10 - slide 40 G-112 OI/OIG Reactor & Materials Overview K-25, in decommissioning since 1985 Oak Ridge Gaseous Diffusion Plant
03/22/10 - slide 41 G-112 OI/OIG Reactor & Materials Overview Paducah GDP, enriching to 5.5% U-235 since 2002 Paducah Gaseous Diffusion Plant
03/22/10 - slide 42 G-112 OI/OIG Reactor & Materials Overview Portsmouth GDP, in standby Portsmouth Gaseous Diffusion Plant
03/22/10 - slide 43 G-112 OI/OIG Reactor & Materials Overview Regulations The GDPs are regulated under 10 CFR 76 Actually certified to operate rather than licensed like Part 70 facilities Recertifications are required under the Atomic Energy Act of 1954 and the Energy Policy Act of 1992
03/22/10 - slide 44 G-112 OI/OIG Reactor & Materials Overview Regulations Certification allowed the NRC to take into account the baseline safety established by the plants during their extended operating history, rather than providing an initial justification for operation NRC recertified the two GDPs; recertification is valid until December 31, 2013.
03/22/10 - slide 45 G-112 OI/OIG Reactor & Materials Overview Basic Theory Gaseous Diffusion uses molecular diffusion to separate the isotopes of uranium Three basic requirements are needed Combine Uranium with Fluorine to form Uranium hexafluoride (UF6)
Pass UF6 through a porous membrane Utilize the different molecular velocities of the two isotopes to achieve separation
03/22/10 - slide 46 G-112 OI/OIG Reactor & Materials Overview More Basic Theory Enrichment of 235U through one porous membrane (or barrier) is very minute Thousands of passes are required to increase the enrichment of natural uranium (0.711%) to a usable assay of 4 or 5% for use in reactors
03/22/10 - slide 47 G-112 OI/OIG Reactor & Materials Overview Gas flow through a Stage
03/22/10 - slide 48 G-112 OI/OIG Reactor & Materials Overview Typical Enrichment Stage
Uranium Properties 238U is most abundant 234U increases with enrichment Watch activity ratios 0.0001 0.001 0.01 0.1 1
10 100 Nat Low Depl Uranium Isotope Percent U-238 U-235 U-234 LEU DU
03/22/10 - slide 50 G-112 OI/OIG Reactor & Materials Overview Feed Cylinders Arriving at Plant
03/22/10 - slide 51 G-112 OI/OIG Reactor & Materials Overview Lifting a cylinder filled with solid UF6
03/22/10 - slide 52 G-112 OI/OIG Reactor & Materials Overview A Whole Lot of DU!
03/22/10 - slide 53 G-112 OI/OIG Reactor & Materials Overview Potential Hazards Primary overall hazard is a major UF6 release Liquid cylinder drop is most credible When UF6 reacts with water, it forms hydrofluoric acid Both corrosive and toxic Accidental criticality at enrichments > 1%, with large radiation release
03/22/10 - slide 54 G-112 OI/OIG Reactor & Materials Overview Decrease in Radiation Dose with Distance from Criticality Accident ~ 3 x 1017 fissions 400 rad at 15 ft LD 50/60 (50% mortality)
Mortality near 100%
9000 rad x (3.16/10)2
= 900 rad (Inverse Square law)
03/22/10 - slide 55 G-112 OI/OIG Reactor & Materials Overview Tickling the Dragons Tail
03/22/10 - slide 56 G-112 OI/OIG Reactor & Materials Overview Acute Radiation Damage to Hands
03/22/10 - slide 57 G-112 OI/OIG Reactor & Materials Overview View of Right Hand -
24 Days Post-Exposure
03/22/10 - slide 58 G-112 OI/OIG Reactor & Materials Overview View of the Torso 24 Days Post-Exposure
03/22/10 - slide 59 G-112 OI/OIG Reactor & Materials Overview Other Significant Hazards The primary fire hazard is the Lube Oil system Primary radiological hazard is exposure of operating personnel to a major UF6 release And then there are chemical hazards With over 600 separate chemicals used at the GDPs
03/22/10 - slide 60 G-112 OI/OIG Reactor & Materials Overview U Enrichment by the Gas Centrifuge Process
03/22/10 - slide 61 G-112 OI/OIG Reactor & Materials Overview Views of a Urenco Gas Centrifuge Cascade
03/22/10 - slide 62 G-112 OI/OIG Reactor & Materials Overview Current Gas Centrifuge (GC) Activities LES Facility Proposed URENCO/LES facility in Lea County, New Mexico - National Enrichment Facility (license issued to LES on 6/23/2006 ) - up to 5%
U-235 enrichment The proposed National Enrichment Facility will be the first commercial facility in the United States to use gas centrifuge technology for enriching uranium
03/22/10 - slide 63 G-112 OI/OIG Reactor & Materials Overview Current Gas Centrifuge (GC) Activities USEC Facility NRC issued a 5-yr license to USEC in February, 2004 to construct and operate a U enrichment test and demonstration facility at Portsmouth GDP, Piketon, Ohio Facility is called the American Centrifuge Lead Cascade Facility and will have up to 240 full-scale centrifuges In August 2004, USEC submitted a license application to NRC to build and operate the American Centrifuge Plant, a full-scale U enrichment plant, at Portsmouth GDP. The application is currently under review. NRC issued its SER in 9/2006.
U-235 enrichment level would be up to 10% at the USEC facility
03/22/10 - slide 64 G-112 OI/OIG Reactor & Materials Overview Atomic Vapor Laser Isotope Separation AVLIS Well see Elvis, before we see AVLIS U metal feed - no UF6 !
03/22/10 - slide 65 G-112 OI/OIG Reactor & Materials Overview FUEL FABRICATION
03/22/10 - slide 66 G-112 OI/OIG Reactor & Materials Overview Objective of Fuel Fabrication Convert enriched UF6 into UO2 fuel pellets, suitable for use as fuel in a reactor NRC licenses fuel fabrication plants under 10 CFR Part 70
03/22/10 - slide 67 G-112 OI/OIG Reactor & Materials Overview Fuel Fabrication Facilities Licensed By NRC Licensee Facility Location Typical Operations Conversion Process Final Product(s)
AREVA-L Lynchburg, VA LEU pellet loading, assemblies None LWR Assemblies AREVA-R
Lynchburg, VA HEU/RTR fuels, Downblend Several HEU/RTR assemblies, LEU materials Global Nuclear Fuels-Americas Wilmington, NC LEU conversion, pellets, assemblies Dry LWR assemblies Nuclear Fuel Services, Inc.
Erwin, TN HEU/RTR fuels, Downblend Several HEU/RTR assemblies, LEU materials Westinghouse (BNFL; Toshiba)
- Columbia, SC LEU conversion, pellets, assemblies Wet (dry standby)
LWR assemblies NOTE: LEU is typically less than 5 wt % 235U.
HEU enrichment typically involves > 90 wt % 235U
03/22/10 - slide 68 G-112 OI/OIG Reactor & Materials Overview Westinghouse Facility
03/22/10 - slide 69 G-112 OI/OIG Reactor & Materials Overview UF6 received from enrichment facility in cylinders packed within NRC/DOT packaging Cylinders removed from package, weighed, and transferred to UF6 storage pad UF6 Cylinders Arriving at Facility UF6 Receipt, Handling and Storage
03/22/10 - slide 70 G-112 OI/OIG Reactor & Materials Overview They are "dished" slightly on each end. End taper allows pellets to expand and contract through drastic temperature changes inside reactor without damaging fuel or cladding materials Pellet Production Final machined pellets are typically about 0.5 inch in length & about 0.33 inch in diameter.
03/22/10 - slide 71 G-112 OI/OIG Reactor & Materials Overview New Fuel Assembly Fuel Rods Fuel Rods and Assemblies
03/22/10 - slide 72 G-112 OI/OIG Reactor & Materials Overview Assembly is shock-mounted so that damage does not occur during transport to customer which is usually performed by truck Shipping Container
03/22/10 - slide 73 G-112 OI/OIG Reactor & Materials Overview Fuel Fabrication Hazards UF6 release Criticality Chemicals used in process
03/22/10 - slide 74 G-112 OI/OIG Reactor & Materials Overview Mixed Oxide (MOX)
Fuel Fabrication Objective is to remove 33-35 MT of surplus Pu from US and Russian weapons programs 5-8% Pu in pellets + ordinary LEUO2 pellets Pu and MOX powder more radiotoxic than ordinary UO2 pellets
03/22/10 - slide 75 G-112 OI/OIG Reactor & Materials Overview Fabricate MOX fuel at Savannah River site, SC Facility would be operated by Shaw Areva (formerly known as Duke, Cogema, and Stone & Webster, or DCS) and owned by DOEs NNSA MOX fuel to be used in Duke Powers Catawba and McGuire NPPs NRC issued a construction authorization on March 30, 2005 NRC received an OL application from DCS in 9/2006 and a revised application in 11/2006 Mixed Oxide (MOX)
Fuel Fabrication
03/22/10 - slide 76 G-112 OI/OIG Reactor & Materials Overview Blended Low-Enriched Uranium (BLEU) Project NRC has approved 3 license amendments to authorize Nuclear Fuel Services (NFS), Erwin, TN to proceed with the BLEU project Project would convert about 33 metric tons of surplus highly enriched uranium from DOE into useable commercial reactor fuel for TVA
03/22/10 - slide 77 G-112 OI/OIG Reactor & Materials Overview NRC inspections of BLEU facilities already being performed Materials would be processed in uranyl nitrate, oxide conversion, and effluent processing buildings Quantities of low-enriched uranium would be stored onsite for future processing into fuel for TVA nuclear plants (i.e. Browns Ferry Nuclear Plant)
Blended Low-Enriched Uranium (BLEU) Project
03/22/10 - slide 78 G-112 OI/OIG Reactor & Materials Overview Questions?