Presented by: Jonathan Silvester Oliver Kiernan

Maxey Flat Site Located in Fleming County, Kentucky Low level Nuclear Disposal Facility o Isolate waste from people and the environment until radionuclides have decayed to non hazardous levels 1 of 6 waste disposal sites created in the US Approximately 663 people live within 2.5 miles Located on one of the largest flat top ridges in the area

History of Maxey Flat Site Nuclear Engineering Company bought site Application to bury nuclear waste granted 1974 – Plutonium detected outside site boundary 1977 – Site Closed 1986 – Site placed on National Priorities List 1995 – Clean up of site begins

Waste Disposal Served 832 corporations A 279 acre waste burial site Consisted of 52 trenches “Hot Wells’ for special nuclear material 4,750,000 cubic feet of waste stored

Reasons for Failure Poor planning and design o Site soil wrong composition o Highly permeable soil used for Protective Cap Poor site organisation and management o Spills cleaned with standard earth moving equipment o Poorly placed waste o Waste not in suitable containers Poor government legislation o Guidelines of high and low level radioactive waste

Reasons for failure – Bathtub Effect Build up of water in trenches caused by greater seepage into trench Capped with 3-10 feet of soil Not concrete or steel Collapsed due to rain water Water became radioactive Nuclear waste overflowed out of the trenches

Impacts Radiation detected extremely small o 1 in 40 million chance of getting cancer No major health or environmental implications However, great concerns with; o Rainwater runoff o Groundwater flow o Air Born Pollutants Immediate closure of site Multi million pound clean up operation

Contaminants Contaminated all areas of the site “Indicator contaminants” were of concern o Radionuclides;  Tritium  Cobalt-60  Strontium-90  Plutonium-238/239 Tritium was of the greatest concern o Most abundant o Most mobile o Easily able to form tritiated water o Non Radionuclides;  Arsenic  Benzene  Lead  Cyanide

Clean up Process Main objectives; o Minimize infiltration/ mitigation of rainwater and ground o Stabilize site for long term cap o Reduce risks to human health and environment 7 alternative remedial solutions o Dynamic Compaction o Vertical infiltration prevention methods o Horizontal infiltration prevention methods All subjected against 9 criteria's Chosen solution – Natural Stabilization o Allow materials to stabilise o Permanent cap o Reviews every 5 years

Natural stabilization Consists of 4 stages; 1) Initial Closure period – Completed May 2003 Remove, solidify & store leachate Demolish buildings & grade site Initial cap placed Install Monitoring equipment 2) Interim maintenance – Current stage (35 – 100years) Monitor natural stabilisation Provide buffer zone 3) Final closure period Installation of Final cap 4) Custodial maintenance Begins once final cap completed