UPDATE ON SPENT NUCLEAR FUEL RETRIEVAL AT THE DOE HANFORD SITE

摘要

In early December 2000, the Spent Nuclear Fuel Project on the Hanford NuclearrnReservation successfully shipped the first of 2100 metric tons of spent nuclear fuel to a new dryrnstorage facility. The objective of the project is to remove the threat of contamination to thernColumbia River, of which the Hanford Reach is the last free flowing stretch. The project usesrnremote systems in the Hanford Site’s K Basins to reduce exposure to operators performing therndecapping, washing, sorting, and repackaging of the fuel. This paper discusses the equipmentrninvolved in the fuel retrieval process.rnThe design requirements were based on minimal development and deployment whilernminimizing radiological exposure to personnel during the fuel retrieval campaign. Minimalrndevelopment limited the risks for schedule and cost, and minimal deployment minimizedrndisruption of the facility's ongoing operations. The result is a mixture of manual past practices,rnremote control, and computer control.rnThe fuel retrieval process removes lids from the fuel canister, washes the fuel assemblies,rnsorts the assemblies into loadable fuel and scrap, and puts the loadable fuel into the fuel basket.rnThe baskets are loaded with 48 to 54 fuel assemblies and placed into the multicanister overpack 5rnor six deep, depending on the fuel type. The multicanister overpack is sent to the cold vacuumrndrying facility to remove moisture then sent to the canister storage building for long term dryrnstorage. The fuel retrieval process is intended to remove visible sludge and corrosion productsrnfrom the spent nuclear fuel assemblies. Inadequately cleaned fuel assemblies can lengthen therndrying process and corrosion products pose a pressure buildup problem within the multicanisterrnoverpack.rnAfter installation, the selected systems were put through four phases of testing. The firstrnphase tested individual systems. Phase 2 testing involved proficiency tests using canisters withrnsimulated fuel elements. Once the process was being satisfactorily performed, DOE gave