Management of Commercially Generated Radioactive Waste - U.S. ...

4.59
Because of the lower radionuclide content and the integrity of the waste packages, no
significant releases of radionuclides are anticipated from any of these conceptual TRU waste
storage facilities. However, effluents would be monitored to verify that this is indeed
true and to provide early detection of problems that might arise.
4.4.3.1 Vault Storage of RH-TRU (Example Method for Drummed RH-TRU)
In the vault storage concept for remotely handled wastes, the waste is considered to
be packaged either in special canisters (0.76 m dia x 3 m) or in 55-gal drums. Vault stor-
age is the example concept of this Statement for these 55-gal-drum-packaged wastes and an
alternative concept for these canistered wastes.
The 55-gal drums that require remote handling are simply stacked in cells constructed
of reinforced concrete. The drums are unloaded from the shipping container and are placed
in the storage cells by a crane using a vacuum-operated lifting device. The design calls
for each cell to contain 500 drums; these are five layers of drums, 100 drums in each layer,
and plywood sheets separate the layers. The basic storage module contains 40 such cells
holding a total of 20,000 drums. Facility designs were evaluated for storage both at an
individual fuel reprocessing plant and at an independent site serving a number of reproces-
sing plants.
The vault storage concept for the canistered waste uses individual sleeves for canister
storage in concrete vaults, which provide radiation shielding. The canisters are handled
with a remotely operated crane. They are lowered from shipping casks through a special
transfer device into the storage space and a shielding plug is placed above the canister.
Each storage space is a galvanized steel pipe (0.9 m in dia) with a plate welded to the bot-
tom and is suspended from the roof slab of the vault. Natural air circulation through the
vault provides canister cooling. The vault storage concept for canisters is based on a
modular design. Each cell has a capacity of 312 canisters. Facility designs were evalu-
ated for siting both at an individual fuel reprocessing plant and at an independent site
serving a number of reprocessing plants.
4.4.3.2 Dry-Well Storage of RH-TRU (Example Method for Canistered RH-TRU)
The dry-well storage concept, which is the example concept of this Statement for the
storage of canisters containing the fuel residue and some of the failed equipment, involves
construction of storage spaces in an above-grade soil structure (berm). The canisters are
placed in individual storage spaces positioned vertically in the berm, and the spaces are
capped with steel and concrete plugs. The plug, canister, and shipping cask are handled
remotely using a crane. Each storage space consists of a galvanized steel pipe sleeve
(0.9 m in dia) with a plate welded to its bottom and suspended from a slab; gravel is back-
filled around the outside of the pipe. Heat is removed by conduction through the soil to
the atmosphere. The basic module designed for the dry-well storage of canisters has two
berms, each containing 1,248 storage spaces.