Radioactive Materials Management NUCP2311

Low Level and High Waste Treatment Options Low level – diluted – dispersed – If short T 1/2 can let decay High level – Usually concentrated – Needs to be contained – Isolate from environment 2

Treatment Technology Categories Transfer – Processes that remove radioactive species from a waste stream and transfer them to another medium (e.g., filtration and ion exchange). Concentration – Processes that reduce the waste volume (e.g., evaporation, crystallization, and drying). Transformation – Processes that concentrate radwaste by changing its physical form (e.g., incineration, calcination, compaction). 3

Special Case: Solidification Candidates: Ion exchange resins, filter sludge, chemical concentrates (boric acid, sodium sulfate), decontaminated solutions, contaminated oil, and fuel fabrication sludges. Possible Technologies: Cement, bitumen (asphalt-type material), urea formaldehyde (not permitted in the US), and DOW media (commercial polymer) 4

5 J.H. Saling and A.W. Fentiman, “Radioactive Waste Management,” Second Edition, (Taylor & Francis, NY  London) 2002.

Volume Reduction 6

Disposal charges are calculated in dollars per cubic foot. Take care not to move into a greater (and more expensive) class. Three general methods: – Compaction – Incineration – Evaporation 7

Super compaction Used to reduce volume of material Can range from several 1000 lb/sqi to 1.5 million lb/sqi Can reduce a 200 lb 55-gal drum to about 6 inch tall No liquids, compressed gasses, etc

Incinerators Idea is to reduce volume of waste by turning into ash, then dispose of the ash Only good for material that will reduce Need very good filters and scrubbers Good for bio hazard wastes as well

Evaporation Reduce down the volume of liquid waste Turn Liquid waste into solid waste Need to worry about concentration of waste as to not move up to a the higher waste category, gets very expensive Need to worry about criticality problems

11 J.H. Saling and A.W. Fentiman, “Radioactive Waste Management,” Second Edition, (Taylor & Francis, NY  London) 2002.

12 J.H. Saling and A.W. Fentiman, “Radioactive Waste Management,” Second Edition, (Taylor & Francis, NY  London) 2002.

13 J.H. Saling and A.W. Fentiman, “Radioactive Waste Management,” Second Edition, (Taylor & Francis, NY  London) 2002.

14 J.H. Saling and A.W. Fentiman, “Radioactive Waste Management,” Second Edition, (Taylor & Francis, NY  London) 2002.

Short and Long Term Disposal/Storage Options

Shallow land burial in earthen trenches Engineering units with layered cap systems in unsaturated soils Modified version of what we are doing now Can design unit to leach material back into soil at which it would have if the soil had not been disturbed Possible Management Alternatives for Radioactive Waste

Alternatives Drilling vertical shafts into granite, rock salt, tuff, or basalt - Mining cavities into specific formations - Deeper earth disposal (i.e. submantle)  Similar in nature, idea is to place material far enough away from the biosphere where it will not bother anyone. Volcano disposal?

Alternatives  Salt Formation Disposal -Replace removed oil or gas with liquid or slurried solid radioactive materials in Salt domes or salt beds. - No water, Isolated stable formation

 Aboveground disposal or longer-term isolation in engineered structures  Molten metal solidification  Radioisotope transmutation  Recycling or reuse of material  Other methods – Space disposal, ocean and sea bed disposal, ice sheet disposal, isolation by disposal on a remote island Possible Management Alternatives for Radioactive Waste Possible Management Alternatives for Radioactive Waste

Investigation Into the Assured Isolation Concept The concept is generally described as an aboveground waste management system for isolating LLRW that inhibits the release of radioactive constituents into the environment.

Solidification Metal or glass solid – Decreases amount of leaching from waste – Stable over long time – Vitrification Recycle – Use material for some thing else, such as using activated metals for shielding material for other power plants or accelerators

Transmutation Using neutrons, or some other nuclear reaction, to change the radionuclide in question into some thing else that can be better managed Change a long live radionuclide to a shorter Change the nuclide into one that can be used for something

Alternatives Deep sea bed disposal- place waste in special containers and let gravity embed the containers well into the silt at the bottom of the deep ocean Space Disposal- place material in a pod and send it into space or into the sun Ice sheet Disposal- let the heat generated by the waste melt its way to the bottom of the Antarctic ice sheets, ice will refreeze over hole

Questions