Radioactive Waste Overview

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Radioactive Waste Overview

• High Level Radioactive Waste
• The U.S. NRC describes high-level radioactive
  wastes as the highly radioactive materials
  produced as a byproduct of the reactions that
  occur inside nuclear reactors. High-level wastes
  take one of two forms
• Spent (used) reactor fuel when it is accepted for
  disposal
• Waste materials remaining after spent fuel is
  reprocessed
• Spent nuclear fuel is used fuel from a reactor
  that is no longer efficient in creating
  electricity, because its fission process has
  slowed. However, it is still thermally hot,
  highly radioactive, and potentially harmful.
  Until a permanent disposal repository for spent
  nuclear fuel is built, licensees must safely
  store this fuel at their reactors.

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Low Level Radioactive Waste

• Classes of Waste
• Class A
• Class B
• Class C
• Three existing low level radioactive waste
  disposal facilities
• Barnwell, SC
• Hanford, WA
• Clive, UT

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Low Level Radioactive Waste

• Waste is disposed in Low Level Disposal
  Facilities.

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Low Level Radioactive Waste

• Low Level Radioactive Waste is encapsulated
  either by solidification or placement in High
  Integrity Containers.

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High Level Radioactive Waste
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Fuel Rods Filled With Pellets Are Grouped Into
Fuel Assemblies
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Fuel Assemblies Cool Temporarily in Used Fuel
Pools
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Dry Fuel Storage at Plant Sites
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Temporary Dry Fuel Storageat Power Plant Site
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Dry Fuel Storage Projects

• ENERCON Services has provided engineering
  services for 18 Dry Fuel Storage Projects
  throughout the US.

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Dry Fuel Storage Projects

• Dry Fuel Storage Projects include design and
  engineering for
• Storage Pad
• Facility Security
• Electrical
• Federal Licensing
• Local and State Permitting
• Cask Heavy Load Lifting

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Transportation Containers Are Strong and Safe
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Transportation Casks Have Been Tested
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Container Loaded on a Truck
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And Crashed at 80 MPH into a Concrete Wall
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Container Broadsided by Locomotive Traveling at
80 MPH
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Containers Survived Incineration Tests
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Containers Passed Every Test
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NRC Concludes Shipping Even Safer Than Previously
Thought
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At the Repository, Fuel Will Be Transferred to a
Special Disposal Container
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Yucca Mountain Being Considered As Disposal Site
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Yucca Mountain Being Considered As Disposal Site
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Seven Miles of Tunnels Built in Yucca Mountain
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Yucca Mountain Has Been Thoroughly Investigated
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President Recommends Yucca Mountain
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New Nuclear Power and Climate Change Issues and
Opportunities
Lunch Keynote Presentation William Sweet Senior
News Editor IEEE Spectrum
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New Nuclear Power and Climate Change Issues and
Opportunities
Student Presentation Ashish K Sahu and Sarina J.
Ergas University of Massachusetts - Amherst
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Perchlorate Reduction in a Packed Bed Bioreactor
Using Elemental Sulfur

• Ashish K Sahu and Sarina J. Ergas

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Background

• Perchlorate (ClO4-)
• Stable
• Non reactive
• Trace levels of Perchlorate
• Disruption of hormone uptake
• in thyroid glands

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Geographic Contamination

• No National Standards
• MCL set by the Commonwealth of Massachusetts
• (2 mg/L)
• California advisory levels (6 mg/L)
• Other states (NY, NV, AZ, CO, TX) 18 mg/L

Ref ewg.org
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Sources of Perchlorate

• Natural
• Atmospheric Sources
• Chilean nitrate fertilizer
• Anthropogenic
• Missiles, Rockets
• Fireworks
• Leather Tannery Industries
• Fertilizers

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Treatment Processes

• Physical Processes
• Chemical Processes
• Biological Processes
• Combination of the above

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Perchlorate Treatment Processes
Physical
Destructive Process
Hybrid Technologies
Chemical
Biological
GAC
Bioreactors
Others
RO/NF
CC-ISEP
Phytoremediation
Reducing metals
IX
Electrodialysis
Others (MBR)
CSTR
PFR
Bio-remediation
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Outline

• Biological Perchlorate Reduction
• Use of Elemental Sulfur
• Experimental Protocol
• Results
• Conclusions

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Biological Perchlorate ReductionPrinciple
Microorganisms convert perchlorate to chloride

• Heterotrophic microorganisms
• Use organic carbon as their carbon source
• Electron donors are methanol, lactate, ethanol,
  wastewater

• Autotrophic
• microorganisms
• Use inorganic carbon as their carbon source eg
  NaHCO3
• Electron donors are S, Fe0, H2

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Use of Elemental Sulfur

• 2.87 S 3.32 H2O ClO4- 1.85 CO2 0.46 HCO3-
  0.46 NH4 ?
• 5.69 H 2.87 SO42- Cl- 0.462 C5H7O2N
• Electron Donor Elemental Sulfur
• Electron Acceptor Perchlorate
• Carbon Source Bi-carbonate
• Low biomass production
• Low nutrient requirements
• Anoxic conditions
• Alkalinity destroyed

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Advantages of Elemental Sulfur

• Waste byproduct of oil refineries
• Excellent packing media
• Relatively inexpensive and easily available
• Applications in packed bed reactors and permeable
  reactive barriers

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Objectives

• Enrich a culture of Sulfur Utilizing Perchlorate
  Reducing Bacteria (SUPeRB)
• Investigate the use of packed bed bioreactors to
  treat perchlorate contaminated waters by SUPeRB
• Test the bioreactor for varying operating
  conditions

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Batch Culture Enrichments

• Denitrification zone of Berkshire wastewater
  treatment plant, Lanesboro, MA
• 5mg/L ClO4-, So and oyster shell, nutrients in
  groundwater
• Analytical Techniques
• pH
• ClO4- concentration using IC (EPA method 314.0)

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Batch Culture Enrichment (SUPeRB)
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Packed Bed Reactor

• Reactor inoculated with SUPeRB
• Media Elemental Sulfur pellets (4 mm), oyster
  shell (31 v/v)
• Volume 1 liter
• Ports 5 ports

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Packed Bed Reactor Operation
Experimental Phase Perchlorate concentration mg/L EBCT hrs Recirculation Ratio QR/Q So particle size
Phase I 5-8 13-100 Intermittent at (40-1,500) 4 mm
Phase II
Reactor 1 0.08-0.12 25-30 50-1,000 4 mm
Reactor 2 0.08-0.12 NO3--N (10 mg/L) 8-30 None 4 mm
Reactor 3 0.08-0.12 8-30 None 0.85 mm
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Bioreactor Performance-Phase II(Effect of Empty
Bed Contact Time (hrs))
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Bioreactor Performance-Phase II(Effect of Empty
Bed Contact Time)
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Bioreactor Performance-Phase II(Effect of sulfur
size particles)
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Bioreactor Performance-Phase II(Effect of
Nitrate on Perchlorate Removal)
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Summary

• SUPeRB reduced ClO4- from 5 mg/L to lt0.5 mg/L in
  15 days using S0 and OS
• High levels of perchlorate (5-8 mg/L) were
  successfully reduced to lt 0.5 mg/L in the
  bioreactor at an EBCT of 13 hours
• Low levels of perchlorate (80-120 mg/L) were
  reduced to lt 4 mg/L at an EBCT of 8 hours

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Summary

• Presence of nitrate did not inhibit perchlorate
  reduction
• Perchlorate reduction was somewhat independent of
  media particle size

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Applications and Future Work

• Pilot scale of system for perchlorate remediation
• Ex-situ remediation
• In-situ remediation by Permeable Reactive
  Barriers (PRBs)

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Acknowledgements

• Water Resources Research Center (WRRC), TEI at
  UMass-Amherst
• Massachusetts Technology Transfer Center (MTTC)
  for commercial potential
• Advisor Dr. Sarina Ergas
• Teresa Conneely, Department of Microbiology for
  FISH and microbiology analysis
• Tach Chu and Charlie Moe (High School) for
  culture and bioreactor maintenance