ML20137H544
| ML20137H544 | |
| Person / Time | |
|---|---|
| Site: | 07001113 |
| Issue date: | 03/28/1997 |
| From: | Reda R GENERAL ELECTRIC CO. |
| To: | Weber M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 9704020276 | |
| Download: ML20137H544 (34) | |
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()'ll0 GENuclear Energy 6enerw va:nc cran Q(,
ra sa ma ww?qw;cwr swsne March 28,1997 Mr. M. F. Weber, Licensing Branch, NMSS U.S. Nuclear Regulatory Commission Mail Stop T 8-D-14 1
Washington, DC 20555-0001 Subject License Renewal-ISA for DCP Summary
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Reference:
(1)
NRC License SNM-1097, Docket 70-1113 (2)
License Renewal Application,4/5/96 i
(3)
Submittal, RJ Reda to ED Flack,5/6/96
)
(4)
Submittal, RJ Reda to RC Pierson,5/14/96 (5)
Letter, RC Pierson to RJ Reda,7/l8/96 1
(6)
Submittal, RJ Reda to RC Pierson,8/30/96 i
(]
(7)
Submittal, RJ Reda to ED Flack,9/26/96 (8)
Letter, MA Lamastra to RJ Reda,10/2/96 (9)
Submittal, RJ Reda to MA Lamastra, 11/22/96 (10)
Application, RJ Reda to MF Weber, 12/16/96 (11)
Letter, MA Lamastra to RJ Reda, 12/17/96 (12)
Letter, RJ Reda to MF Weber,2/5/97 (13)
Letter, MA Lamastra to RJ Reda,2/10/97 (14)
Letter, RJ Reda to MF Weber,2/19/97
Dear Mr. Weber:
As part of our facility modifications for the Dry Conversion Process (DCP), and as part of our site license renewal for NRC license SNM-1097, GE committed to complete an Integrated Safety Analysis (ISA) for the DCP and submit a summary of that work to the NRC. In accord with that commitment, GE submitted the ISA Summary for the DCP on 2/19/97. In '.his transmittal, the Summary has been expanded to include the integration of the DCP with the curr mt facility alA the waste treatment t.ssociated with DCP. This now summarizes the key ISA basis for safety for the operation of DCP at the Wilmington facility. This submittal replaces the ISA document submitted to you on 2/19/97 in its entirety.
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i Six copies of this submittal are being provided for your use.
L Please contact Charlie Vaughan on (910) 675-5656 or me on (910) 675-5889, if you have any questions or would like to discuss this matter further.
Sincerely, G8 NUCLEAR ENERGY t
Ralph J.
eda, Manager Fuels & Facility Licensing Attachment cc:
' RJR-97-040 0;
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Mr. M. F. Weber March 28,1997 Page1of1 O
ATTACIIMENT TO LETTER FROM RJ REDA TO MF WEBER DATED MARCII 28,1997 ISA
SUMMARY
GE WILMINGTON DRY CONVERSION PROCESS DATED MARCII 28,1997 O
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Dry Conversion Process i
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l GE Nuclear Energy j
Wilmington, NC
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i SupplementalInformation to License Renewal:
SNM-1097, Docket 70-1113 i
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ISA Summary C)
GE Wilmington Dry Conversion Process Table of Contents i
Title Page Table of Contents i-v Introduction 1
ISA Teams 1
Procedures, Techniques and Tools 1
Process Organization 2
Methodology 2
Huilding Design Basis 5
General P JP Areas 5
_oss of moderation control in the DCP Facility due to water ingress 5
Fire / Explosion within the DCP Facility 6
Radiological exposure of personnel to airborne uranium 6
Asphyxiation of worker from excessive concentrate of nitrogen 7
Failure of the distributed process control system 7
Cylinder Storage and llandling 7
Loss of containment external to DCP leading to release of UF6 to the 7
environment Vaporization 8
UF6 release due to a loss of UF6 cylinder integrity within the autoclave 8
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Table of Contents
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Title g
Vaporization (cont'd) 8 UF6 release to the room due to failure of UF6 piping 8
1 Cold trap rupture leading to release of UF6 9
Criticality due to backflow of steam moderator into the cylinder 9
l Conversion 9
I Loss of hydrogen containment leading to fire or explosion including loss 9
of HF containment and uranium containment Loss of moderation control leading to criticality in the kiln and 10 I
associated reactor and outlet hopper l
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Criticality in HF areas caused by release of particulate uranium to 10 unfavorable geometry liquid system O
Criticaiity in the HF area caused by a reiea e orunreacied UF aseeeu 10 6
uranium to unsafe geometry Loss of moderation control due to backflow ofliquid from the HF area 11 1
Exposure of an operator to HF, steam, or radiological hazards from 11 l
backflow of reactor contents during recycle operations l
Personnel injury caused by moving machinery and rotating parts 11 l
Powder Outlet 12 l
Excess moderator in the cooling hopper 12 Homogenization 12 Excess moderation by introduction of hydrogenous material such as pore 12 l
former, die lubricant, water or oil i
Radiological exposure of personnel to airborne uranium caused by loss 13 ofcontainment
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Personnel injury caused by rotating parts on the sifter and homogenizer 13 ii of v I
Table of Contents Title Page Blending, Slugging, Granulation and Tumbling 13 Excess moderation by introduction of too much hydrogenous material, 13 for example pore former or die lubricant, as a result of errors in weight, additive or mixing Excess moderation as a result of wet powder 14 Excess moderation as a result of oil 14 Radiological exposure of personnel to airbome uranium caused by loss 14 ofcontainment Personnel injury caused by moving machinery and rotating parts 15 Powder Pack 15 i
Radiological exposure of personnel to airborne uranium caused by loss 15 ofcontainment Personnel injury caused by moving machinery and rotating parts 15 Container St srage And Handling 15 Exceed moderation restricted area limits by overfilling storage 16 containers, introduction of too much hydrogenous material, or violating spacing requirements for containers Large powder container falls on a person 16 HF Area 16 Criticality in HF area caused by excess uranium in the off-gas collected 16 in unfavorable geometry liquid system Release of fluorides through the stack to the environment 17 Employee exposure to excessive HF 18 Environmental spill ofliquid HF 18 Fire or explosion in the HF building or off-gas line 18 O
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s Table of Contents Title lage a
GeneralIntegration Areas 19 Exceed moderation limits inside a large unfavorable geometry feed 19 container as a result of the introduction of too much hydrogenous material, non-uniform distribution of moderator, or violation of spacing requirements for storage arrays Loss of geometry, mass, or moderation control for favorable geometry 19 containers stored on conveyors Loss of moderation control in the integration areas as a result of a 19 powder spilling outside approved storage container (s)
Personnel injury as a result of a large powder container falling 20 Fire / Explosion within the Integration Area 20 i
Radiological exposure of personnel to airborne uranium 20 Q
Asphyxiation of a worker from excessive concentration of nitrogen 21 UO Press Feed 21 2
Loss of moderation control leading to criticality inside a bicone feed 21 container when re-tumbling is required Personnel injury caused by a dropped powder storage container 21 Gadolinia Shop 22 Exceed moderation limits inside a large powder feed containu m n 22 result of too much hydrogenous material, non-uniform distrihm... of moderator, or violation of spacing requirements for storage arrays Loss of moderation control due to an error in additive addition at the 22 DM-10 vibromill or roll-tumbler Personnel injury and exposure to airborne contamination caused by a 22 container dropped from a crane from an elevation of up to 23 feet Personnel injury caused by moving machinery and rotating parts 22 O
arr " crc'e 23 Asphyxiation of a worker from excessive concentration of nitrogen 23 iv of v
Table of Contents Title P_mge a
Dry Recycle (cont'd) 23 Excess moderator from moist powder 23 Excess uniform or non-uniform moderation by introduction of 23 l
hydrogenous material such as pore former, die lubricant, water or oil Radiological exposure of personnel to airborne uranium 24 HVAC 24 Loss of moderation control in MCA and MRA 24 Moisture condenses on powder as a result of a failure of the chilled 24 water supply in the HVAC system Excessive build-up of uranium in HVAC system 24 m
Waste Treatment 25 V
Employee exposure to liquid or vapor HF, and/or environmental release 25 ofHF Unloading a etch acid truck into the HF tank would put nitrates into the 25 fluoride effluent, which would exceed the NPDES discharge limits.
Unloading a HF truck into the etch acid tank could exceed the temperature rating of tank V-700, resulting in damage / failure.
If acid is added to lime without the agitator running, the acid and lime 25 slurry would layer, not reacting completely. If the agitator is then tumed on, the layers would disperse and react. Such a sudden reaction would release the normal amount of energy, but over a shorter time. This could I
result in localized overheating and vapor generation, possibly leading to tank failure.
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mU ISA Summary GE Wilmington Dry Conversion Process Introduction An integrated safety analysis (ISA) was performed to support the new dry conversion process at the GE Wilmington site. The analysis was conducted in accordance with Chapter 4, Integrated Safety Analysis, of SNM Licce 1097, submitted April 5,1996, as amended. The purpose of the analysis was to determine potential accident scenarios and risk, to ensure that controls are in place to prevent and/or mitigate accidents, and to rank the controls in relation to the risks which they mitigate so that the proper level of assurance measures can be applied to each. The broad scope of the analysis included criticality safety, radiological safety, environmental protection and industrial safety, including chemical safety and fire protection. This report summarizes the important results of the safety study for the dry conversion facility and affected sections of the fuel h,-
fabrication facility. Detailed records are retained on-site.
ISA Teams The ISA was performed by teams of people of different expertise who systematically analyzed the hazards in a focused meeting environment. Each team included expertise in criticality safety, radiological safety, industrial safety and environmental protection. Also included were process and controls engineers. Because the process had never been operated at the Wilmington site, experts in the operation of existing plants utilizing this technology participated along with GE personnel.
Procedures, Techniques, and Tools l
l The ISA team used the Hazop method and limited use of the What if method to complete the analysis. The hazop analysis was facilitated by and documented in a software package known as HazopPC, developed by Primatech, Inc.
This software was customized for GE to specifically capture nuclear hazards. Consultants from Primatech provided training to team participants early in the project, and facilitated the preliminary sessions.
Guidance for performing the analysis came from Primatech and from gc 4
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' Guidelines for Hazard Evaluation Procedures'. As the project neared completion, an
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internal procedure, P/P 10-20, Integrated Safety Analysis, was developed to define how future ISAs would be performed and how the results ofISAs would be used to manage risk in the operating factory.
Process Greanization The DCP ISA was broken into the following segments and analyzed using the method shown:
Cylinder Movement - Hazop i
Vaporization - liazop Conversion - Hazop Powder Outlet - Hazop Homogenization - Hazop Blending, Precompaction, and Granulation and Tumbling - Hazop HF Treatment - Hazop Containers / Storage - Hazop Powder Pack - What If Powder Transfer Corridor - Hazop UO Press Feed - Hazop 2
(3 Gadolinia Shop - Hazop U
Dry Recycle Area - Hazop Waste Treatment - Hazop HVAC - Hazop Methodology Hazards were identified using historical input from a variety of sources including safety information from other dry conversion facilities and public domain documents from other sites in the fuel cycle. The relationships between the hazards and DCP process deviations were developed through guided brainstorming and event visualization techniques.
Where the hazop methodology was used, each process segment was divided into logical nodes. For each node, the team first considered the intended operating conditions. Next they considered the possible deviations from the design intention using a list of i
parameters and guidewords. Typical parameters included:
Flow Temperature
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' Guidelinesfor Ha:ard Evaluation Procedures, Second Edition with li'orked Examples, Center for Chemical Process Safety of the American Institute of Chemical Engineers, New York,1992.
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Pressure O
comeositioa Level Weight Guidewords were used to identify possible deviations from normal. Example guidewords included:
No/None More Less As Well as Part of Reverse Other than Once possible deviations were identified, possible causes of the deviations were hypothesized. The consequence of the deviation was estimated through experience or technical evaluation. The severity of each consequence was rated on a three-point scale, shown in Exhibit 1. The likelihood of the accident occurring with no controls in place was estimated from experience on a three-point scale, shown in Exhibit 2. Safeguards or controls that prevent or mitigate the consequence were identified. Outside of the team environment, the controls were ranked in importance by the unmitigated risk, where:
(Risk)onmitigatea = (Severity) x (Likelihood)onmitigasca The level of unmitigated risk was used to determine the level of assurances that would be applied to the controls. Risk ranking is summarized in Exhibit 3.
Finally, the likelihood of the consequence occurring with the controls in place was estimated. Final risk was used by the team to judge the adequacy of the controls, where (Risk)rmai = (Severity) x (Likelihood) mitigated if the final risk was judged by the team to be too high, recommendations for improvement were captured and reviewed with management. Recommendations that were adopted were tracked to completion.
Consequences associated with UF. and HF were estimated using past experiences of GE Wilmington, FBFC, and other uranium processing facilities and experiences in the chemical industry. Criticality consequences were estimated using standard analytical methods. Radiological consequences were estimated by extrapolating our experience with the existing processes. Environmental, industrial, and chemical consequences, including fire and explosion, were estimated with the aid of material safety data sheets, chemical interaction information, and various modeling techniques, including emission calculations and dispersion models for fence-line concentration.
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4 Exhibit 1 Severity of Consecuences AU Severity Radiological /
Environmental /
Ranking Criticality industrial / Chemical exposure to an individual member of fatality 3
the public off-site (5 rem, 30 mg intake
. medical treatment for a member of the ofU) public off-site severe exposure to an employee (400 permanent disability e
rem internal plus extemal dose or 230 off-site contamination above regulatory mg intake of U) standards exceed regulatory hmits for employee serious injury e
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exposure (5 rem,10 mg U internal) exceed permit limits or regulatory limits e
lost time injury e
reportable release exceed administrove hmits on daily air OSHA recordable injury e
1 samples, lung Nunts, bioassays,
. Crst aid contaminatior., TLDs e
exceed internallimits 10% of annral exposure limit spillinside containment Unusual incident (UIR)
Exhibit 2 Likelihood Level Frequency Likelihood 3
more frequent than once Likely to occur in the immediate future every two years 2
every two to fifty years Likely to occur during the life of the facility 1
less frequent than once every Not likely to occur during the life of the facility 50 years.
O incredible Likehhood is indistinguishable from zero.
k Exhibit 3 Risk Matrix C
3 Mid-level o S Risk n e 8
- 2 Low Risk Mid-level Rhk-q r u i e i 1
Low Risk Low Risk Mid-level Risk n
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2 3
e Likelihood O
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Buildine Desien Basis The DCP facility has been designed to meet the relevant building and fire protection standards. The design criteria were taken as bounding assumptions by the ISA teams with respect to external events, of which heavy rain, lightning strikes, and high wind are considered credible. The DCP facility is designed with a structural integrity providing a safety factor of two. It is built to withstand a sustained wind speed of 120 mph. Although the seismic activity is not considered credible, the DCP facility has been designed to meet the lateral acceleration requirements for Wilmington, North Carolina, as contained on the contour maps in <fSCE 7-93. The electrical classification is Class I, Division. 2, Group B in close proximity of the conversion kilns, where there is some risk of II escape.
2 Elsewhere within DCP, the electrical hazard classification is non-hazardous. The GE Wilmington site is located above the 100 year flood plain and thus is not considered susceptible to storm surge or flash floods.
What follows is a summary of the more significant potential accidents identified and discussion of the controls that are in place to protect against them.
General DCP Areas PURPOSE: To provide a facility where moderation is restricted, fire or explosion is
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unlikely, and radiological exposure or contamination is minimized.
ACCIDENT: Loss of moderation control m the DCP Facility due to water ingress.
PROTECTION: The DCP process areas are designated as Moderation Restriction Areas
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(MRA). The building is designed to be water tight. The roof of the DCP building is designed to prevent water leaks and to provide an early warning of potential degradation.
Its special multi-layered construction incorporates a reinforced concrete slab roof deck, an EPDM membrane, a drainage system of extruded polystyrene insulation, a concrete slab over geotextile fabric, and a fully adhered butyl sheet. Degradation of the external barrier i
is detected by a visual observation of water in the drainage system. Also, there are no i
penetrations on the roof of the building, and the roof slopes from east to west to convey rain water away to a gutter and downspout system on the west side of the building.
Air handling equipment is designed to minimize the possibility of water entering the Moderation Restricted Areas in DCP.
Moisture detectors and alarms are fitted downstream of the last coil on the air intake to DCP. While small amounts of water on the floor do not present a safety problem, the ground floor of the DCP building is raised in relation to the existing FMOX ground floor to prevent in-leakage of water from rising water.
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ACCIDENT: Fire / Explosion within the DCP Facility O
PROTECTION: The DCP building is designed to comply with relevant fire codes.
Interior doors and walls provide fire resistance.
A comprehensive fire alarm and detection system includes smoke and heat detectors as well as H and HF detectors. Fire 2
alarm horns annunciate in the LCP building and in the HF building. Alarm signals are relayed to both the DCP control room and to the Site Emergency Control Center.
The HVAC system is protected by fire-retardant HEPA filters and fire dampers in the ductwork. Consistent with the Moderation Restriction Area, only carbon dioxide fire extinguishers are installed within the DCP building. A water sprinkler system protects the HF building. Operating and maintenance personnel receive fire fighting emergency training and are periodically tested by unannounced emergency evacuation exercises.
H2 is handled and processed within closed systems. Ignitable concentrations of H are
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2 prevented by positive mechanical ventilation. Hydrogen sensors are located within each kiln room, and continuously monitor atmosphere for unacceptable concentrations of hydrogen.
The DCP kiln generates a low specific surface area product, which is resistant to spontaneous oxidation in storage. Further protection against oxidation includes powder cooling, nitrogen blankets, and interrupted mixing cycles.
!O ACCIDENT: Radiological exposure of personnel to airborne uranium.
PROTECTION: A general feature of the design of the DCP facility is the containment and ventilation philosophy to provide defense in depth against the escape of airbome uranium into areas in which personnel would not normally be required to wear personal protective equipment. Specifically, airborne uranium is contained by nit ogen seals at the connections between the processing equipment and storage / transfer contons. Uranium processing activities are housed within ventilated rooms, designed so that the lowest i
pressure is within the rooms themselves and air flows from outside to inside the rooms.
Each room has HEPA filtration to trap particulates within the room, and the air intake and j
extraction ducts are arranged to draw air downward and away from personlel work areas and provide adequate air changes to avoid static air pockets. Ultimately, the extracted air j
is filtered through another llEPA filter bank before discharge to the environment.
Redundant fan capacity and fan failure alarms are provided on the DCP HVAC system.
Operating procedures require floor operators to inspect the plant areas on a routine basis.
Existing GENE practices require operators to clean up visible contamination as soon as it is discovered. Tight fitting connections equipped with infiatable seals are installed at all container filling and dump stations. Where flexibility is required in the powder feed pipework, rubber boots and internal metal sleeves are used to limit powder spillage in the C
event of a rubber boot failure. Operating and maintenance personnel are required to wear Page 6 of 25 I
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the designated personal protective equipment when breaking primary containment on Q
uranium processing equipment.
A large powder spill within a containment room are evident when the operator views the operations through a window or enters the room to remove the container.
1 ACCIDENT: Asphyxiation of a worker from excessive concentration of nitrogen.
PROTECTION: Nitrogen piping systems were designed to exceed the anticipated operating pressures, and are pressure tested during installation. In the event of a leak in a process room, positive ventilation provided by the HVAC system is designed to supply j
adequate air changes. The HVAC system is equipped with redundant fans to assure reliability.
Plant procedures for entering confined spaces protect workers during maintenance of the large vessels such as the homogenization blender.
1 ACCIDENT: Failure of the distributed process control system 4
PROTECTION: All valves are designed to fail in a sale position in the event of a total control system outage. Active safety controls are implemented separately from functions that may be needed for normal operating functions and access, resulting in a more robust q
software operating system. Changes to the software are subject to strict version control O
per procedure. Important controls are functionally tested before start up and periodically thereafter.
Cylinder Storage and Handling PURPOSE: Safe movement of UF feed material into and out of the facility.
6 ACCIDENT: Loss of ontainment external to DCP leading to release of UF6 to the environment.
PROTECTION: UF6 cylinder integrity complies with the 30B type specification defimed in USEC 651 Rev. 7. Jan 1995. The process design ensures that cylinders are handled only when the UF6 inside them is in the solid phase. Cylinder lifting equipment has been designed and tested to handle the load. Operator training in UF6 cylinder handling includes the use of forklift trucks, cranes and hoists. Cylinders are moved with the cylinder valve cover in place and lifted to the minimum lift height consistent with the terrain. Overpressurization of a cylinder due to fire is prevented by strict control of the inventory of hydrocarbon fuels and combustible materials in the UF6 cylinder storage area as described in NUREG 1491. Existing administrative controls for the receipt and release of UF6 cylinders ensure that overweight cylinders or enrichments greater than 5% nU are 2
O not Processed in oCe.
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o of UF6 cylinders ensure that overweight cylinders or enrichments greater than 5% nU are 2
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not processed in DCP.
Vaporization PURPOSE: Supply UF6 gas to the reactor where it is converted to UO powder.
2 ACCIDENT: UF release due to a loss of UF cylinder integrity within the autoclave.
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PROTECTION: The autoclave has been manufactured to meet the ASME pressure vessel code, and is pressure-tested annually. The rated pressure exceeds the normal operating pressure of the UF cylinders. The integrity of the door seal is tested each time 6
a cylinder is loaded into the autoclave. A door latch proximity switch is interlocked with the cylinder heating cycle. Loss of seal pressure disables the autoclave heating sequence.
The internal pressure within each cylinder is verified to be below atmospheric pressure before heating as a safeguard against overpressurization during the heating cycle.
The UF6 cylinder pressure is controlled at the desired set point by monitoring the UF61.ne pressure dowustream of the cylinder, and uses feedback control to regulate the carmnt supplied to the autoclave heaters. Active controls prevent overpressurization of the cylinder by de-energizing the autoclave heaters on high temperature at the cylinder n
surface, or high temperature inside the autoclave.
V UF leak detection is installed as part of each autoclave system, and draws a sample from 6
the autoclave annular space. The annular space is swept with heated dry nitrogen to prevent reaction with air in the event of a UF leak. This nitrogen may be fed at high pressure to suppress potential leakage of UF. As a result, a leaking cylinder can continue 6
feeding safely to the reactor until the cylinder is empty and the hazard is reduced.
To protect workers from exposure during cylinder installation, personnel are required to wear appropriate personal protective equipment when connecting and disconnecting the UF line pigtail to the cylinder.
6 ACCIDENT:
UF release to the room due to failure of UF piping.
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PROTECTION: The piping integrity is assured by 100% radiographed welds on all UF6 lines. UF -resistant gaskets are used at flanges, and bellows-sealed valves minimize stem 6
leaks. The UF line is further protected against failure due to hydraulic rupture by 6
automatic temperature control of the trace heating with high and low temperature alarms and high temperature interlocks that disable the affected section of trace heating.
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' UF6 leak detectors are installed in each autoclave room. In the event of a UF leak in an 6
O autoclave room, the ve itilation to that room is shutdown to contain the UF6 inside.
ACCIDENT: Cold trap rupture leading to a release of UF6 PROTECTION: The cold trap has been manufactured and tested in compliance with ASME and CODAP pressure vessel codes. The cold trap heaters are disabled on high temperature, high presst. e, or high weight. Valve line-ups are interlocked to prevent the inadvertent transfer of 146 to unintended destinations, for example, cylinder-to-cylinder or cylinder-to-cold trap during conversion.
ACCIDENT: Criticality due to backflow of steam moderator into the cylinder.
PROTECTION: During operation of the plant, a positive flow of gas is maintained from the UF6 line to the reactor. Active controls automatically isolate the cylinder from the reactor in the event that positive pressure differential between the cylinder and reactor is lost. The UF6 cylinder skin temperature must be above a predetermined minimum value before the UF6 feed valve can be opened.
o Conversion V
PURPOSE: To convert UF into ceramic-grade UO powder suitable for pelletizmg.
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This process includes the recycle of discrepant UO powder to reduce fluoride content.
2 ACCIDENT: Loss of hydrogen containment leading to fire or explosion. (Also loss of HF containment leading to worker injmy or loss of uranium containment leading to personnel exposure.)
PROTECTION: The primary protection against loss of containment is the kiln itself.
The kiln seals are oflabyrinth construction with the interspace pressurized with nitrogen.
The kiln is protected from overpressure by an automatic pressure control system.
Pluggage of the sintered metal filters at the gas discharge of the kiln could result in a pressure higher than desired. The filters are kept clean by a computer-controlled sequence that blows back the metal filters with nitrogen. During operation the pressure drop across the sintered metal filters is continuously monitored. Deviations from normal l
result in audible / visual alarms in the control room. Furthermore a high kiln pressure l
interlock stops the UF feed, followed by an orderly shutdown of the hydrolysis and 6
pyrohydrolysis steam and H2 eeds.
f The kiln and associated vessels are housed inside a ventilated containment area. H2 h
detectors in the rooms automatically stop the H2 and UF feeds to the affected conversion 6
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o kiln l liF detectors send audible / visual alarms to the control room, and the operators are O
trained to manually shutdown the gas feeds to the affected kiln.
ACCIDENT; Loss cf moderation control leading to criticality in the kiln and associated l
reactor and outlet hopper.
PROTECTION: To ensure that the steam fed to the reactor and kiln is dry, saturated steam is superheated using electric heaters equipped with automatic temperature controls regulated by the computer control system. All steam lines are electrically trace heated and insulated. A low temperature condition activates audible / visual alarms in the control room. The heat tracing is equipped with redundant heating circuits.
Low steam temperature fed at the superheater or downstream of the superheater is sensed and interlocked to the steam feed control to the reactor.
Both hydrolysis steam and pyrohydrolysis steam supplies are protected by these controls.
A low temperature inside the reactor or on the reactor wall is sensed and interlocked to the steam and UF feed control. A low temperature interlock on the exterior of the kiln 6
barrel also stops the steam and UF6 feeds. Similar alarms and interlocks are activated by thermocouples located inside and on the exterior of the outlet hopper.
O ACCIDENT:
Criticality in IIF area caused by release of particulate uranium to d
unfavorable geometry liquid system.
PROTECTION: The primary protection against entry of particulate uranium into the ofigas system are the sintered metal filters housed in the top of the reactor. Further protection is provided by a back-up sintered metal filter unit installed in the offgas line downstream of the reactor. The integrity of both sets of filters is assured by continuous monitoring of the pressure drop across the filters. The kiln filters are periodically backpurged with nitrogen during operation to minimize powder build up.
Passive and active controls in the IIF area that prevent criticality are described in the liF section.
ACCIDENT: Criticality in the IIF area caused by a release of unreacted UF aqueous 6
uranium to unsafe geometry.
PROTECTION: An excess of hydrolysis steam (normally a factor of two) is fed to the reactor to provide complete conversion of UF6 to the intermediate UO F. Furthermore, 22 sufficient pyrohydrolysis steam is provided to convert all the UF6 to UO2F and to UO in 2
2 the event ofloss of the hydrolysis steam flow. A high UF6 low interlock closes the UF f
6 feed valve and starts sweeping nitrogen to the injector nozzle. Similarly, low steam flow Page 10 of 25
u Other potential causes of a loss of steam flow to the reactor, for exarnple, an open manual
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vent valve in steam line, an open pressure relief valve on steam superheater, are mitigated by the low flow interlock described above, operating and maintenance procedures including a ;tartup checkP<t, routine inspections, and vendor-recommended periodic maintenance.
Passive and active controls in the HF area that prevent criticality are described in the HF section.
ACCIDENT: Loss of moderation control due to backflow ofliquid from the HF area.
PROTECTION: The off-gas flow created by the condenser eductor and exhaust fans prevents backflow. Condensation of HF offgas at the condenser creates an additional favorable draft. A passive barometric leg, by virtue of the height difference between the reactor offgas line and the vapor-liquid separator downstream of the HF condenser, prevents siphoning ofliquid to the reactor. Specific engineered controls are summarized in the HF section.
During shutdowns, protection against backflow is afforded by administrative controls which require physical isolation of the reactor from the HF aystem.
ACCIDENT:
Exposure of an operator to HF, steam, or radiological hazards from backflow of reactor contents during recycle operations.
PROTECTION: In the event of a low pressure alarm at the inflatable seal at the recycle feed station, the recycle feed valve closes, preventing airborne contamination at the recycle port. The recycle station is located inside an enclosed kiln room. Operators are required to wear the designated personal protective equipment when making or breaking powder feed connections. A double valve arrangement equipped with a nitrogen purge in between prevents backflow of steam and hydrogen into the recycle container. A low pressure alarm on the recycle feed station alerts the operator to a condition which could result in off-gas flowing to the unicone.
ACCIDENT: Personnel injury caused by moving machinery and rotating parts.
PROTECTION: The kiln drive units, reactor and recycle screw motors are protected adequately by machine guards. The start up checklist includes a step to check that these guards have been refitted following maintenance. A site-wide procedure defines lock-out/ tag-out practices.
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n Powder Outlet p
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PURPOSE: To cool the UO powder and ensure that it meets moisture criteria applicable 2
to the Moderation Restricted Area, and to transfer the powder into transfer containers.
ACCIDENT: Excess moderator in the cooling hopper.
PROTECTION: Controls in conversion that ensure dry powder in the kiln also limit the availability of moisture to condense on the powder. To keep steam from flowing into the cooling hoppers, a valve lock system is installed at the outlet of the kiln. This lock consists of two valves with a dry nitrogen purge between them. The cooling hoppers are further protected by continuous redundant dew point analyzers which measure the free i
moisture in the carrier nitrogen gas. A high moisture interlock stops the UF6 feed to the kiln and initiates a controlled shutdown of the steam flow.
The control system automatically isolates the powder in the cooling hopper until the powder can be transferred under conditions favorable to criticality control requirements.
To prevent overfilling of the unicone on discharge from the cooling hopper, the computer system monitors the weight dispensed into the unicone via the process weigh scales, and f
tenninates the sequence when the set weight is reached. In addition, there is a high weight interlock on the scale at the container filling station that will closes the cooling hopper discharge valve.
V Homogenization PURPOSE: To produce a UO2 powder that is physically and chemically uniform for subsequent pressing into pellets and sintering.
Homogenization breaks down soft agglomerates, removes hard particulate material, and mixes the sifted powder to produce a unifomi batch.
ACCIDENT: Excess moderation by introduction of hydrogenous material such as pore former, die lubricant, water or oil.
PROTECTION: Upstream controls in the conversion area limit the moisture content in the powder. Upstream controls in the recycle area similarly limit the moisture content of the recycled U 0s. A high mass interlock closes the powder feed valve and limits the 3
amount of surface-adsorbed water available for redistribution from the surface of the powder to one spot within the homogenizer.
A computer-assisted administrative control prevents the introduction of feed material containing pore former or die lubricant.
The gearbox for the screw and arm assembly inside the homogenizer contains a special bq non-hydrogenous low moderation oil. The procurement and use of this oil is controlled Page 12 of 25
n The' gearbox for the screw and arm assembly inside the homogenizer contains a special (j
non-hydrogenous low moderation oil. The procurement and use of this oil is controlled via the maintenance planning and control system.
ACCIDENT: Radiological exposure of personnel to airborne uranium caused by loss of containment.
PROTECTION: To prevent airborne contamination, the sifter shaft seals are purged with nitrogen. The sifter and homogenizer are housed within a ventilated containment area, For additional protection, a dedicated containment hood surrounds the sifler and magnetic separator. A high powder level alarm is fitted on the oversize line from the sifter to alert the operator that the oversize bottle requires changing. Administrative controls including i
procedures and operator training ensure that the oversize outlet valve is closed before the bottle is removed.
To prevent overfilling of the unicone on discharge from the homogenizer, the computer system monitors the weight dispensed into the unicone via the process weigh scales, and terminates the sequence when the set weight is reached. In addition, there is a high weight interlock on the scale at the container filling station that will closes the homogenizer discharge valve.
O V
ACCIDENT: Personnel injury caused by rotating parts on the sifter and homogenizer.
PROTECTION: There is an interlock that stops the rotation of the homogenizer screw and arm when the inspection hatches are opened on the top or bottom of the homogenizer.
Also, the sifter rotation stops whenever the top inspection cover is opened or the end cover is removed. A site-wide procedure defines lock-out/ tag-out practices.
l Blendine, Sluccine, Granulation, and Tumbline PURPOSE: The blending operation creates a povider which is of a specific, uniform enrichment. Additives improve compatibility. Slugging followed by granulation, forms a flowable, pressable, granular solid suitable for h.gh quality pressing and sintering.
Tumbling improves flowability of the powder.
ACCIDENT: Excess moderation by introduction of too much hydrogenous material, for example pore former or die lubricant, as a result of errors in weight, additive, or mixing.
PROTECTION: Additives are prepared in separate equipment to prevent mix-ups during processing. Additives are weighed on an accountability scale and labeled. The additive bottle size limits the mass of moderator that can be added at one time. Unique couplings g
()
on the additive bottles and the additive ports assist in the control of the addition.
Page 13 of 25
n v
O The blend pl n defines and documents the quantity and type of additive required for each blend. The computerized traceability system tracks the concentrations of additives and moisture in the powder fed to the blender. Computer systems ensure that each additive addition complies with the blend plan. Additive bottles are barcode labeled, and the computer systems prevent the feed valve from opening if the bottle does not match the i
expected barcode. The computer system provides a final comparison of blend weight to that expected from the blend plan. Local programmable logic controllers lockout the feed j
4 valve on high weight.
4 Rotation of the blender is assured by a sensor to improve the uniformity and reliability of the additive mixing step.
In the tumb!ing operation, additive preparation is protected by similar controls. Only one bottle is available in a tumbling room, and that bottle is administratively controlled so that it is assigned to the correct tumbler. The additive bottle size is limited, ensuring the necessary safety margin for criticality safety control.
ACCIDENT: Excess moderation as a result of wet powder.
j PROTECTION: Upstream controls in conversion limit moisture content in the powder.
bq Similarly, upstream controls in the recycle area limit moisture in the U 0s. A high mass 3
interlock closes the powder feed valve and limits the amount of surface-adsorbed water available for redistribution from the surface of the powder to one spot within the homogenizer.
ACCIDENT: Excess moderation as a result of oil.
PROTECTION: Limited volumes of oils and greases are used on the slug press. The gearbox for the screw and arm assembly inside the blender contains a special non-hydrogenous low moderation oil. The procurement and use of this oil is controlled in the maintenance planning and control system. Grease is external to the granulator and tumbler and is not considered a significant hazard because ofits physical separation from the powder and the small quantity used.
ACCIDENT: Radiological exposure of personnel to airborne uranium caused by loss of
)
containment.
PROTECTION: The blend / slug / granulate and tumbling processes are designed to protect workers from radiological exposure with the same protection described in the General DCP Area section of this report. Additional controls prevent overfilling of the unicone at O
the blender filling station or the bicone at the granulator filling station: the computer Page1 af25
a
.s the blender filling station or the bicone at the granulator filling station: the computer O
system monitors the weight dispensed into the container via the process weighscales, and
~
terminates the sequence when the set weight is reached. In addition, there is a high weight interlock that closes the appropriate powder filling valve.
ACCIDENT: Personnel injury caused by moving machinery and rotating parts.
PROTECTION: There are interlocks that stop the rotation of the screw and arm when the inspection hatches at the top or bottom of the blender are opened. Containment around the rotating turret of the slug press limits access to the moving parts. The inspection hatch on top of the granulator is fitted with a hard-wired interlock which stops the motor when the hatch is opened. A hard-wired door lock on the tumbler room prevents operation of the tumbler mless the door is locked.
Powder Pack PURPOSE:
To dispense UO powder or granules from DCP storage containers to 2
approved containers for shipment to customers.
I ACCIDENT: Radiological exposure of personnel to airborne uranium caused by loss of containment.
O.G PROTECTION:
The container integrity is assured administratively 'vy observing the operating procedures and recommended maintenance. Operators are required to wear appropriate personnel protective equipment when connecting or disconnecting powder feed connections. An inflatable seal assembly is fitted at the container feed station.
Powder packing operations are carried out within a ventilated hood, so that the operator can handle and seal the packed product through arm slits. The slits have adequate face velocity to reduce the risk of escape of airborne contamination.
bCCIDENT: Personnel injury caused by moving machinery and rotating parts.
PROTECTION: The powder packing facility is housed in a separate room adjacent to the main storage area on the first floor of the DCP building. The powder packing equipment includes machine guards which protect operators from moving parts.
Container Storage And Handling PURPOSE: To store large containers of powder containing various enrichments and
,q additives until the powder is needed at pellet press operations.
V Page 15 of 25
a s
ACCIDENT: Exceed moderation restricted area limits by overfilling storage containers,
()
introduction of too much hydrogenous material, or violating spacing requirements for containers.
PROTECTION: Powder is stored in high-integrity closed containers which are routinely inspected and maintained. Container gross, tare and net weights are tracked on the computerized uranium material accountability system. A significant deviation from the official tare weight triggers a discrepancy alarm and halts any subsequent material transactions involving the affected container.
Upstream process controls provide assurance that the uranium product meets the criteria for hydrogen content within the storage area.
A fixed support grid assists opertting persennel to maintain the required minimum spacing between containers. Additional storage is authorized provided it takes place in approved locations.
ACCIDENT: Large powder container falls on a person.
I PROTECTION: The use of cranes and hoists for lifting and transporting containers is covered in a site-wide safety procedure that spells out safe practices and periodic p,
inspection requirements. Operators are trained in the safe use of this equipment.
U l
HF Area 1
1 PURPOSE: To produce nominal 50% aqueous hydrofluoric acid from the hydrogen fluoride off-gas generated during conversion of UF to UO and load the HF product into 6
2 tank trucks for shipment to customers. The facility also scrubs the condenser off-gas to remove residual HF fumes before release to the environment. Dilute HF scrubbing liquid is typically loaded into a truck for delivery to the site waste treatment facility to remove the HF before the water is released to the environment.
ACCIDENT: Criticality in HF area caused by excess uranium in the off-gas collected in unfavorable geometry liquid system.
PROTECTION:
Dual inline sintered metal filters upstream in the conversion process reduce the risk of uranium carryover to the HF area. In the unlikely event that both filters l
fail, each conversion line liquid HF stream is equipped with an individual uranium l
detector. If uranium is detected, the liquid is diverted to a favorable geometry tank known as the polluted tank. If the uranium concentration exceeds a higher trip level, the 6 feed is stopped, followed by an orderly shutdown of the steam feeds to the affected UF kiln. The three HF streams combine in a common stream which passes through another O
uranium detector. if uranium is detected here. the UFe and steam feeds to aii three kiin i
Page 16 of 25 l
i
j'c w.
.3 i
are stopped, and the HF produced during shutdown is diverted to a favorable geometry
- [h.
tank.
1-I The HF condensers are of favorable geometry, and the cooling capacity of the condensers is great enough to trap the UF6 in the event of a catastrophic release from the conversion kiln. The chilled water supply is protected by a low flow interlock at the condenser which stops the UF flow to the kiln. The chilled water supply is also protected by a high l
6 temperature alarm and administrative controls on the set-up of the system.
i-Key manual valves that are opened to prepare the system for maintenance are included in pre-startup checklists, operating procedures, and training to prevent inadvertent by-pass l.
. of safety controls during operation.
i' i
A high liquid level in the vapor liquid separator stops UF6 feed to the affected kiln, and protects against unanalyzed HF condensate backflowing to the unfavorable geometry washing column. If the high level is coincident with uranium concentration detected by-the uranium detector, both UF6 feed and steam flow to the kiln are stopped. Another protection against uranium in the washing column is a high liquid level interlock on the polluted tank that stops UF flow to all kilns.
6 There is a high level sump alarm that annunciates locally in the HF building and remotely in the DCP control room. Administrative controls require that any leakage of HF 1
collected in the dike will be sampled and analyzed for uranium content prior to pumping back to the HF storage tanks or out to the mobile tanker only if the uranium concentration is low. Administrative controls require that any leakage of unanalyzed HF from a piping failure prior to the uranium detectors collected in the dike be sampled and analyzed for uranium. This material is pumped back to the HF storage tanks or out to the mobilc tanker only if the uranium concentration meets established release limits.
ACCIDENT: Release of fluorides through the stack to the environment.
PROTECTION: The kiln off-gas is scrubbed to remove fluorides from the off-gas before it is released to the environment. This process equipment is located inside a building, protected from freezing and severe weather. The temperature and pressure at the top and bottom of the wash column are continuously monitored and alarms locally in the HF building and also in the DCP control room. A low flow of water in the wash column stops the UF6 feed to the kiln (s). In the event of a failure in the water supply, an emergency feed water tank is maintained in a ready state to continue scrubbing until the remaining fluorides in the system are purged from the kiln lines. A high liquid level in the base of the wash column stops UF6 feed to the kilns. The HF stack emissions are administratively monitored to provide a feedback loop so that corrections can be made if the scrubbing process is insufficient to meet requirements.
O Page 17 of 25
.t 1
j O
^cciouxT: emeioree exposure to excessive "F.
i PROTECTION: The HF equipment is designed to maintain integrity. The HF offgas line is PTFE-lined and rated for 250 deg C. Equipment reliability is enhanced by periodic maintenance. The integrity of the air-driven HF pump is protected by a interlock that shuts off the air supply in the event of high discharge pressure. Preventative maintenance of the pump diaphragms is performed in accordance with vendor recommendations.
The building is equipped with safety showers in case of personnel exposure to liquid HF.
Use of personal protective equipment is required when making or breaking containment.
Operators are trained in safe use of personal protective equipment. Operators are required to wear appropriate personal protective equipment during sampling. This requirement is including in operating procedures and training.
HF fumes in excess of the alarm limit activates an alarm in the control room which is audible in the HF building. Additional warning lights are activated at the entrances to HF building. Periodic inspection of the remote HF building is required by the operators. An emergency HF scrubber is available for scrubbing the room air.
All tanks are vented to the wash column. Tank trucks are vented to the wash column.
The tanker loading lines are washed with DI water into the tank truck before the lines are p
disconnected. A vacuum break valve facilitates complete draining of the tanker feed line before breaking containment and minimizes the potential for spills.
ACCIDENT: Environmental spill ofliquid HF.
PROTECTION: The HF storage tanks are installed within a dike designed to contain liquid HF spills. The volume of the diked area is sufficient to contain a spill of the entire contents of the largest tank. The dike comprises two concrete slabs with the top slab coated with an acid resistant medium. A grid is installed between the two concrete slabs which gravity drains to a sample point. Periodic sampling allows for early detection of a breach in the top slab. The tanker loading bay also drains into the main dike and is similarly contained with a concrete slab coated with an acid -resistant coating.
MCIDENT: Fire or explosion in the HF building or off-gas line.
PROTECTION:
The eductor that controls the kiln pressure is operated with nitrogen instead of air. The off-gas from the wash column is diluted to below the lower explosive limit of hydrogen by use of an air blower.
O Page 18 of 25
a
- t
.t General Intecration Areas U
PURPOSE: To provide a region in the current fuel fabrication facility where moderation is restricted, fire or explosion is unlikely, and radiological exposure or contamination is minimized.
ACCIDENT:
Exceed moderation limits inside a large unfavorable geometry feed conta ner (e.g., unicone or bicone) as a result of the introduction of too much hydrogenous material, non-unifomi distribution of moderator, or violation of spacing requirements for storage arrays.
PROTECTIOR The moisture in the powder is controlled at its source in the DCP and scrap recycle oxidation processes. Upstream process controls provide assurance that the uranium product loaded into the container meets strict limits on moisture content.
Administrative controls including operator training and operating procedures provide safety against inadvertent water addition.
The unicone and bicone storage containers are high-integrity closed vessels designed to provide a water-tight seal. The containers are routinely inspected and maintained.
Container gross, tare and net weights are tracked on the computerized uranium material accountability system throughout the process. A significant deviation from the expected weight, which might indicate inadvertent addition of moderator, triggers a discrepancy
)
alarm and halts any subsequent material transactions involving the affected container.
( 'J 1
L Fixed support grids assist operating personnel in maintaining the required minimum spacing between containers.
Other favorable geometry storage containers are also authorized within integration facilities on approved conveyors or floor storage locations.
ACCIDENT:
Loss of geometry, mass, or moderation control for favorable geometry containers stored on conveyors.
PROTECTION:
Loss of geometry, or mass, or moderation is considered in the established can-conveyor storage. Feed can conveyor layout and design is analyzed for specific spacing between conveyors. The mass of a 3-gallon or 5-gallon container is controlled by accountability scales coupled with computer assisted administrMive controls. Moderation in either container is limited by upstream process controls verified through statistical sampling.
ACCIDENT: Loss of moderation control in the integration areas as a result of a powder spilling outside approved storage container (s).
PROTECTION: The integration areas of FMO, where large containers are used, are v
designated as Moderation Restriction Areas (MRAs). In an MRA, moderation is the i
Page 19 of 25
a
- /
. i primary control parameter. By design, an MRA is constructed to limit the amount and O
types of extern 1 moderator sources Administrative controls are also established for j
routine cleanup / maintenance operations. Air handling equipment and ductwork are also designed to minimize the possibility of water entering the MRAs. In some MRAs, movement of containers is supervised by operators trained to avo:1 situations which might subject a container to an unplanned external moderation source.
1 Where large containers are stored unsupervised, the rooms are designed with physical barriers to protect the containers from water. Examples of these physical barriers include a secondary ceiling, walls and curbs, insulation of selected HVAC ducts, controlled drainage, and pipe-in-a-pipe construction of water lines.
Where favorable geometry containers are used in an MCA, the moderation is one of two (or more) independent parameter controls. Thus, loss of moderation as a result of powder spillage outside a favorable geometry container does not, by itself, constitute an unsafe J
condition.
ACCIDENT: Personnel injury as a result of a large powder container falling.
PROTECTION: The use of cranes and hoists for lifting and transporting containers is covered in a site-wide safety procedure that specifies safe practices and periodic p
inspection requirements. Operators are twined in the safe use of this equipment.
O ACC.OENT: Fire / Explosion within the Integration Area PROfiCTION: The building is designed to comply with relevant fire codes. In;enor doors and walls provide fire resistance. HEPA filters in the HVAC system are flame-4 retardant. Smoke detectors monitor the ductwork. The FMO Building is protected by a fire alarm system. Consistent with the Moderation Restriction Area, only carbon dioxide fire extinguishers are installed within the integration areas. Operating and maintenance personnel receive fire fighting emergency training and participate in unannounced emergency exercises.
ACCIDENT: Radiological exposure of personnel to airborne uranium.
PROTECTION:
The facility is designed to provide containment within process equipment, ventilated enclosures, and sealed containers. Inflatable seals are used at the connections between the processing equipment and storage / transfer containers. Uranium processing activities take place in ventilated rooms, designed to maintain negative pressure relative to adjacent areas of less potential for airborne contamination. Room ventilation is designed to draw air downward and away from personnel work areas and Page 20 of 25
- 4 a
t provide adequate air changes to avoid static air pockets. Ultimately, the extracted air is
]
filtered through two HEPA filter banks before discharge to the environment.
Operating procedures require floor operators to inspect the plant areas on a routine basis.
Existing practices require operators to clean up visible contamination as soon as it is discovered. Tight fitting connections equipped with inflatable seals are installed at all container filling and dump stations. Where flexibility is required in the powder feed pipework, rubber boots and internal metal sleeves are used to limit powder spillage in the
{
event of a rubber boot failure. Operating and maintenance personnel are required to wear i
the designated personal protective equipment when breaking primary containment on uranium processing equipment.
A large powder spill within a containment room is evident when the operator views the operations through a window or enters the room to do work.
ACCIDENT: Ophyxiation of a worker from excessive concentration of nitrogen.
PROTECTION:
Nitrogen piping systems are designed to exceed the anticipated operating pressures, and they are pressure tested during installation. The nitrogen supply to containment seals is equipped with a fixed nitrogen accumulator volume and shutoff valves. A low seal pressure gauge provides indication of a possible leak. Room ventilation provides additional protection.
p.)
v UO2 Press Feed
(
PURPOSE: Deliver DCP-type powder to the UO pellet press in bicone containers.
2 ACCIDENT: Loss of moderation control leading to criticality inside a bicone feed container when re-tumbling is rc~.id.
PROTECTION: In addition to the safeguards mentioned in the Ger zal Integration section above, the UO shop is protected from loss of moderation control due to double 2
addition of die lubricant by a computer accountability system which provides computer-assisted administrative controls.
ACCIDENT: Personnel injury caused by a dropped powder storage container.
PROTECTION: Physical restraints keep the operators remote from the container. The forklift is designed to handle the load. The mounting assembly contains guides to aid in the positioning and placement of the bicone. Wheel cocks engage when the unit is in p
place.
Automatic controls require the container to be properly positioned before d
operation can begin.
Page 21 of 25
O E
c' V
Gadolinia Shop PURPOSE: Produce a uniform powder containing uranium oxide, gadolinium oxide, pore former, and die lubricant. This powder must be of uniform concentration and enrichment, and suitable for producing ceramic pellets.
ACCIDENT: Exceed moderation limits inside a large powder feed container as a result of too much hydrogenous material, non-uniform distribution of moderator, or violation of spacing requirements for storage arrays.
PROTECTION: See the safeguards mentioned in the General Integration section above.
ACCIDENT: Loss of moderation control due to an error in additive addition at the DM-10 vibromill or roll-tumbler.
PROTECTION: The weight of additive at the DM-10 is calculated by a computer system. The weight of the measured additive is checked by the system and strictly controlled at the point of entry. Administrative controls associated with the computer O
accountability system prevent double-batching. Additional safety margin is provided by O
the torroidal annular design of the mill and the internal stainless steel media.
Similarly, the weight of the die lubricant additive at the roll-tumbler is calculated by a computer system. The weight of the measured additive is checked by the system and strictly controlled at the point of entry. Administrative controls associated with the computer accountability system prevent double-batching. The favorable geometry design of the roll-tumbling station provides additional margin of safety.
ACCIDENT: Personnel injury and exposure to airbome contamination caused by a container dropped from a crane from an elevation of up to 23 feet.
PROTECTION: The unicone is equipped with multiple latches in the lifting mechanism.
Limit switches require that the load is properly lifted. The crane is designed to handle the load. The system is load-checked periodically. The use of cranes and hoists for lifting and transporting containers is covered in a site-wide safety procedure that spells out safe practices and periodic inspection requirements. Operators are trained in the safe use of this equipment.
ACCIDENT: Personnel injury caused by moving machinery and rotating parts.
Page 22 of 25
9$
e r PROTECTION: The start up checklist includes a step to check that machine guards have
..O been refitted roiiowias maiatea ace- ^ site-wide Procedure defiaes iock-out'tas-out practices.
Dry Recycle
. PURPOSE: To reclaim sintered UO, grinder swarf, or out-of-spec UO and convert it to 2
2 U 0, suitable for blending with DCP powder.
3 ACCIDENT: Asphyxiation of a worker from excessive concentration of nitrogen.
PROTECTION: In addition to the safeguards mentioned in the General Integration section above, plant procedures for entering confined spaces protect workers during maintenance of the large vessels such as the blender.
ACCIDENT: Excess moderator from moist powder.
PROTECTION: Dry recycle oxidation furnace feed materials are limited to sintered UO2 grinder swarf, or other dry uranium oxide powder forms containing less than 5 wt.% H O 2
equivalent by computer assisted material accountability system. Temperature controls across the oxidation furnace tube ensure complete oxidation and limit the moisture in the product U 0, oxide powder. At the furnace outlet, continuous redundant dew point i
3 analyzers measure the free moisture in the carrier nitrogen gas. A high moisture interlock stops material from being discharged into a non-favorable-geometry container. Safe-geometry containers are available to transport high-moisture materials in the event of a moisture excursion.
ACCIDENT:
Excess uniform or non-uniform moderation by introduction of hydrogenous material such as pore former, die lubricant, water or oil.
PROTECTION: Computer-assisted administrative controls on material type limits the dry recycle oxidation furnace feed materials to sintered UO (e.g., Pellets or hardscrap),
2 grinder swarf, or to, or other dry uranium oxide powder forms containing less than 5 wt.% H O equivalent by computer assisted material accountability system.
2 Temperature profile controls and online moisture analysis of the product U30s limit the moisture content of the U 0s in ' downstream' dry recycle proc' esses including blending 3
or vibromilling at the dry recycle DM-10 vibromill.
j The gearbox for the screw and arm assembly inside the blender contains a special non-
- hydrogenous low moderation oil. The procurement and use of this oil is controlled via i
O the maintenance P annies and contrei system. ^dministrative centreis en the mass of i
Page 23 of 25 i
os 1
max'imum blend batch is controlled by a computer system. A high mass mass interlock
("i limit closes the powder feed valve, thereby limiting the amount of uniform moderator available for redistribution.
The weight of additive at the DM-10 is calculated by a computer system. The weight of the measured additive is checked by the system and strictly controlled at the point of entry. Administrative controls associated with the computer accountability system prevent double-batching. Additional safety margin is provided by the torroidal annular design of the mill and the internal stainless steel media.
ACCIDENT: Radiological exposure of personnel to airborne uranium.
PROTECTION: In addition to the safeguards described in the General Integration section above, equipment that is likely to create airborne contamination is contained in an enclosed hood. Spot ventilation is used at the unicone fill station.
IIVAC l
ACCIDENT: Loss of moderation control in MCA and MRA.
O PROTECTION: Physical barriers such as rain caps on exhaust pipes reduce the potential V
for water to enter the system. The HVAC system is designed with drains that are routinely monitored to ensure that they function properly. The system is designed to run as a pressurized exhaust stack, preventing backflow to process equipment and vessel offgas.
ACCIDENT: Moisture condenses on powder t.s a result of a failure of the chilled water supply in the HVAC system.
PROTECTION: The HVAC monitoring and control system alarms in the URU control room and in the HVAC maintenance shop when the humidity limit is exceeded.
ACCIDENT: Excessive build-up of uranium in HVAC system.
PROTECTION: The HVAC monitoring and control system monitors pressure drop across HEPA filters and alarms in URU and HVAC. Passive primary filters are used on all hoods, and operators monitor pressure drop routinely. HEPA filters are changed out as necessary by trained maintenance personnel. Sections of the HVAC ductwork is monitored periodically for excessive buildup.
O Page 24 of 25
b h#
gC Waste Treatment PURPOSE:
Provide a facility where 1-50 wt% HF can be unloaded, stored, and neutralized with lime.
ACCIDENT: Employee exposure to liquid or vapor HF, and/or environmental release of HF.
PROTECTION: Pumps are operated remotely and can be shutdown from multiple locations. Personnel protective equipment is provided and required when breaking containment. Safety showers and eye wash stations are provided. To protect against an environmental release, the storage tanks are diked to contain a spill. The concrete floor is equipped with leak collection channels and sight-tubes at the low points. Pumps are enclosed inside spray containment boxes. The tanks are vented to a scrubber, which was designed to handle fumes generated from high heats of dilution. The tank overflow lines have a liquid seal to prevent fumes from escaping.
ACCIDENT: Unloading a etch acid truck into the HF tank would put nitrates into the
(]
fluoride effluent, which would exceed the NPDES discharge limits. Unloading a HF truck into the etch acid tank could exceed the temperature rating of tank V-700, resulting in damage / failure.
PROTECTION: The etch and HF hoses are not interchangeable, they have different size l
hose connections.
ACCIDENT: If acid is added to lime without the agitator running, the acid and lime i
l slurry would layer, not reacting completely. If the agitator is then tumed on, the layers would disperse and react. Such a sudden reaction would release the normal amount of energy, but over a shorter time. This could result in localized overheating and vapor j
generation, possibly leading to tank failure.
PROTECTION: Interlock on agitator amps, must indicate that agitator is operating.
/'N U
Page 25 of 25