ORNL is managed by UT-Battelle, LLC for the US Department of Energy Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations Oak Ridge National Laboratory Joanna McFarlane Mike Poore August 13, 2019 A1
ORNL is managed by UT-Battelle, LLC for the US Department of Energy
Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Oak Ridge National Laboratory
Joanna McFarlaneMike Poore
August 13, 2019
A1
Slide 1
A1 PowerPoint doesn’t have a tracking feature, but you can follow these steps to compare the new file to the original and review my suggestions:1. Open the original file on your computer and click the Review tab.2. Click the Compare button. A window will open, and you will be prompted to choose a file to merge with the original presentation.3. Navigate to and select the edited file, and then click Merge.4. A new file will open showing revisions in comment balloons. The revisions can be reviewed, accepted, or rejected. However, when the file is saved, it will not maintain the revision information.Author, 8/6/2019
22 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Introduction
• Objectives
• Scope of work
• Report overview
33 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Non–Light Water Reactor Policy and Technical Guidance Support, Letter of Technical Direction #6
• Tasks– ORNL shall collect information (and identify documents) on hazards: nuclear
criticality, fire, radiation, and reactive or toxic chemicals– The investigation shall consider hazards that are part of the primary process
operations, that are part of supporting operations (e.g., actinide recovery, waste management) or that are the result of design features or process equipment used for conducting primary or supporting operations
– The investigation shall consider . . . normal operations as well as those that are part of nonroutine operations (e.g., startup, maintenance)
44 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Deliverables
• Kick-off meeting summary
• Letter report on major information sources
• Hazards report
• Knowledge management meeting with NRC staff
55 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
• ORNL/TM-2019/1195
• Available on www.osti.gov
66 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Background
• Types of fuel salts
• Historic fuel salt preparation facilities– Aircraft Reactor Experiment– Molten Salt Reactor Experiment (MSRE)– Stripping of uranium from MSRE fuel and flush salts
77 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Non-reactor site fuel salt processes and hazards
• Salt component synthesis
• Synthesis of MSR fuel salt
• Packaging and transportation of enriched UF6 and UF4
88 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Reactor site fuel processes and hazards
• Liquid salt operations
• Fuel loading
• Fuel sampling
• Off-gas system
• Insoluble fission product filtering
• Soluble fission product separation
• Waste form preparation
99 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Fuel salt processing hazard tables
• Process identified
• Salt type and process objective
• Refers to relevant report sections for the process
• Important hazards to consider for the process
• Qualitative assessment of maturity of process (TRL)
• Qualitative assessment of degree of hazard to operators(1–5)—no information on likelihood of exposure to hazard
• Engineering strategies to mitigate exposure to hazard
1010 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Excerpt:Table 3a. Off-site nuclear fuel preparation and handling (continued)
Table 3a. Off-site nuclear fuel preparation and handling (continued)
Physical or chemical process
Salt type andprocess objective
Relevant report sections
Key hazards
Qualitative assessment
Qualitative severity judgment
Mitigation strategiesTRL: 1 (low) to 9
(high)Rank: 1 (low) to 5
(high)
• Salt purification• Hydrofluorination
Removal of oxides/hydroxides from fluoride salts
3.1.1
• H2/HF• Be if present as the
BeF2 salt component• Heat (650°C)• Contamination if
actinides present
7 4
Standard contamination control
for unirradiated materials
• Salt purification• Chlorination
Removal of oxides/hydroxides from chloride salts
3.1.1
• CCl4, Cl2, COCl2, HCl• Heat• Contamination if
actinides present
7 5
Standard contamination control
for unirradiated materials
• Packaging and transportation
Actinides and nonfissile components
3.3
• Contamination if actinides present
• Air-sensitive• Be (if present as
BeF2)
9 3Double barrier
container
1111 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Fluoride salt production loop (Sections 2.2, 3.1.1)
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Excerpt:Table 3c. On-site fuel processing hazards during power operations
Table 3c. On-site fuel processing hazards during power operations
Physical or chemical process
Salt type and process objective
Relevant report sections
Key hazardsQualitative assessment
Qualitative severity judgment
Mitigation strategiesTRL: 1 (low) to 9 (high) Rank: 1 (low) to 5 (high)
Online sampling offuel salt during operation
Fluorides, chlorides to give salt composition
2.2.3, 4.3
• Very high radiation• Very high contamination
(leakage of volatile FP, actinides in salt & entrained aerosols)
• Heat• Air sensitive• Be (if present as BeF2)
4 5
• Remote handling• Inert gas flush• Double barrier
containment
Online sampling of fuel salt when loading salt during operation
Fluorides, chlorides to give salt composition
2.2.3, 4.3
• Flow restrictions/ pressure due to plate-out/freezing
• Very high radiation • Very high contamination
(leakage of volatile FP, actinides in salt & entrained aerosols)
• Criticality• Heat• Air sensitive • Be (if present as BeF2)
2 2
• Remote handling• Rapid measurements
(pressure, temperature, salt density)
• Purge gas pressure relief• Secondary containment
1313 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
MSRE sampler enricher (Sections 2.2.3 and 4.3)
1414 Review of Hazards Associated with Molten Salt Reactor Fuel Processing Operations
Summary—Wide range of hazards
• Hazards depend on fuel salt, processing operation, fissile material concentration, radiation level, and other toxic or hazardous materials
• Tables are used to summarize hazards in report
• Differences from solid-fueled reactors:– Refueling and adjustment of fuel salt chemistry online– Fuel processing closely coupled with reactor operations– Off-gas important for fission product confinement during normal operations
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Limitations of assessment
• MSR designs for the reactors and support systems are not fully mature, so only an overview of hazards can be provided based on the likely salt processing steps
• Limited experience with MSRs
• Can extrapolate from larger non-nuclear halide salt use
• Cannot assess inadvertent criticality during initial fuel transfer