[en] Two facilities for storing spent nuclear fuel underwater at the Hanford site in southeastern Washington State being removed from service, decommissioned, and prepared for eventual demolition. The fuel-storage facilities consist of two separate basins called K East (KE) and K West (KW) that are large subsurface concrete pools filled with water, with a containment structure over each. The basins presently contain sludge, debris, and equipment that have accumulated over the years. The spent fuel has been removed from the basins. The process for removing the remaining sludge, equipment, and structure has been initiated for the basins. Ongoing removal operations generate solid waste that is being treated as required, and then disposed. The waste, equipment and building structures must be characterized to properly manage, ship, treat (if necessary), and dispose as radioactive waste. As the work progresses, it is expected that radiological conditions in each basin may change as radioactive materials are being moved within and between the basins. It is imperative that these changing conditions be monitored so that radioactive characterization of waste is adjusted as necessary