The K East and K West Basins have been the storage locations for the majority of Hanford's spent nuclear fuel since the 1970's. Recently, other spent fuel in wet storage in various other Site locations was consolidated there. In order to move the fuel out of the K Basins and through the Spent Nuclear Fuel (SNF) Project "Path Forward" to safe, dry storage, much new equipment has been designed, built and placed in the K Basins.

Upgrades and equipment installations began first in K West Basin, and fuel removal began there on December 7, 2000. The K West Basin houses several operations, collectively known as Step 1, in the path to ending the environmental threat posed by Hanford's spent fuel. K East Basin fuel will be moved into the K West Basin and processed through the parts of Step 1 using K West Basin equipment. Special transfer containers and loadout equipment in the K East Basin will accomplish this movement.

Fuel Retrieval System In K West Basin

The Fuel Retrieval System (FRS) in the K-West Basin, a system of multiple underwater components, opens the aging, existing fuel canisters; removes, sort and clean the fuel; and loads the fuel assemblies into specially designed steel baskets. A Cask Load-Out System (CLS), loads the fuel-containing baskets into Multi-Canister Overpacks (MCOs). The MCOs are pre-staged underwater in shipping casks that will move them out of the K West Basin. The 32-ton, K West Basin crane then hoists each shipping cask out of the water and onto a special transport truck that takes it to the nearby Cold Vacuum Drying Facility.

The K West Basin FRS is a complicated, first of a kind system consisting of six main sub-systems. It is comprised of thousands of specially fabricated and assembled individual pieces of steel machinery and electronics. Good radiation control practices require that all FRS operations be conducted underwater.

De-Capper, Primary Cleaning Machine And Queue Table

The decapping station, or de-capper, begins the fuel handling process by opening the K West Basin canisters inside a box designed to capture radioactive gasses and sludge. (Spent fuel assemblies in the K-East Basin are not stored in sealed canisters, so this fuel foes not require de-capping.)

A larger steel box adjacent to the de-capper box contains a primary cleaning station, where the fuel canisters are rotated in the Primary Cleaning Machine (PCM). The PCM is a drum-type washer wherein the fuel is flushed with a water stream to remove corrosion products. Such products contain hazardous materials and water-bearing compounds that generate gases which would be undesirable during long-term dry storage.

Next, the fuel canisters are unloaded onto one of three underwater process tables where the fuel assemblies undergo inspection, sorting and removal of any foreign objects or debris still clinging to them. Fuel then is loaded into steel baskets, with intact fuel segregated in separate baskets from fuel pieces that have broken into scrap. The baskets are set on queue tables (an underwater staging deck) to await loading into the MCOs.

Konan Arms

The FRS system handles much of the fuel using a robotic system with manipulator arms known as "Konan." The unique Konan system was designed and built specifically for the SNF Project. The Konan arms can rotate in six different planes of operation, and are capable of picking up fuel scrap pieces as small as dimes when used by skilled operators. The arms simulate human arms in that they are capable of multiple movements, including up, down, circular, pitch and yaw movements at shoulders, elbows, wrists, and finger-like jaws. Each arm itself weighs about 350 pounds, and is connected to a mast and bridge that weighs approximately an additional 1,250 pounds. The arm has a reach of about six feet, and works above the central fuel sorting table in the K West Basin. On two smaller process tables, fuel is handled by manually operated tongs and grapples. In general, intact and/or undamaged fuel is processed on the smaller tables using the manual equipment, while fuel that is damaged or more difficult to handle is processed by the Konan manipulators.

Once inspected, each fuel piece is turned upright and measured in a go/no-go gauge to determine whether it will fit in new steel baskets fabricated to hold it during drying and storage. The elements that pass the gage are then loaded into the new baskets using a "stinger" tool, an expandable device dangling from a flexible cable. An operator maneuvers the stinger into the end of the upright fuel, expands the tool, lifts the fuel slightly, and places it in a new basket.

Integrated Water Treatment System

Throughout the underwater fuel sorting, cleaning and loading operations in the K West Basin, an Integrated Water Treatment System (IWTS) filters the basin water and collect particulates and soluble contaminants (sludge) generated by the fuel cleaning process. Collection of these materials maintains water clarity and optimal working conditions.

Like the FRS, the IWTS is complex and unique; designed and built especially for the SNF Project. The K West Basin IWTS has a four-stage water filtration system and uses three submerged pumps to collect basin water from three separate FRS process locations. It then passes the water through a knock-out pot, ten settling tanks, three filter vessels containing sand and garnet that filter particulates, and three ion exchange modules that chemically remove soluble contaminants. A new combined water filtration system and sludge collection system is being designed for the K East Basin.

Cask Loadout Station

The Cask Loadout Station (CLS) in the K West Basin consists of a shuttle to move the loaded baskets containing fuel from the queue table area, through a transfer channel, to a location adjacent to a transportation cask that is staged in the south load-out pit of the basin. Additionally, the CLS contains a gantry to raise the baskets, place them into the MCO and cask, and place a shielding plug into the top of the MCO. A 32-ton overhead crane then hoists the fully loaded casks out of the basin water and onto trucks for transport to the Cold Vacuum Drying Facility.