|Oct15-11, 10:57 AM||#1|
Nuclear Waste Reprocessing
I'm doing a paper on reprocessing and vitrification of high-level nuclear waste, but I'm coming up short on peer-reviewed sources (my school's database of journals doesn't seem to include nuclear engineering). Does anyone know any good places to find sources on this material, or any specific papers I might find interesting? I'm not trying to make other people do my assignment for me; I'm just at a loss on what to do. I find the topic interesting, and I'd like to explore it as much as a seven page paper will allow.
|Oct15-11, 01:20 PM||#2|
Try the IAEA and
SPENT FUEL REPROCESSING OPTIONS. IAEA, VIENNA, 2008. IAEA-TECDOC-1587.
Use of Reprocessed Uranium
Status and Trends in Spent Fuel Reprocessing
More at - http://iaea.org/OurWork/ST/NE/NEFW/n...lications.html
use 'save target as' to download pdfs.
IAEA-TECDOC-1563. Spent Fuel and High Level Waste: Chemical Durability and Performance under Simulated Repository Conditions.
Various articles here
Processing of Used Nuclear Fuel
http://www.world-nuclear.org/info/default.aspx?id=466 = http://www.world-nuclear.org/info/inf69.html
International Nuclear Waste Disposal Concepts
Synroc - http://www.world-nuclear.org/info/inf58.html
The Pyro- and Hydrometallurgical Processing of Uranium-Containing Waste
High-level waste borosilicate glass
http://www.osti.gov/bridge/servlets/...e/10173218.pdf (12 MB)
|Oct20-11, 11:06 AM||#3|
French vitrification and activated materials disposal in Universal Canisters:
Can someone explain this to me? This document says that gamma radiation level at freshly filled canister with vitrified fission products/actinides is, quote:
"γ Dose rate at 0 m (contact) 14000 Gy/h"
"Decay heat 1750 W"
1.4 million rads/hour!?? This looks awfully high. I mean, one accident with such canister falling out of shielded storage or loading machine, and some unlucky worker might get lethal dose in seconds.
These canisters are 1.33 m high and 0.43 m wide, elsewhere I found information that their wall thickness is 0.5 cm (=0.005m).
Why the wall is so thin? That's not even close to, say, 2.5 cm of steel required to cut gamma level in half.
To my naive eye the idea of making walls thicker in order to make gamma levels somewhat less insane seems straightforward.
|Oct20-11, 12:23 PM||#4|
Nuclear Waste Reprocessing
As far as I know, the waste canisters are handled remotely in a vault in an engineered storage facility, or they can be stored underwater or in a vertical shaft. If they are transported to another facility, they are shipped in a special steel shipping container. The processing of the waste, the loading and unloading of the canisters, and handling and final disposal are done remotely. The walls of the facilities are rather thick in order to absorb the radiation.
|Oct20-11, 01:08 PM||#5|
This container has very thick walls and weighs x10 more than canisters it contains.
So, adding some protection to the canisters not only would make them less "hot", but will (1) either enhance transport safety: if container is breached, the exposed canisters will "shine" less, or (2) allow to use lighter container. For example, if canister walls are made 2.5 cm thick, the transport container can be made nearly twice as light.
I would like to learn more about rationale behind canisters' dimensions and wall thickness. I already wrote about wall thickness; regarding canister width - it seems that wider canister would be better because the vitrified waste in its center is substantially shielded by the waste at the walls, making its contribution to the total gamma level greatly attenuated. Basically, bigger (wider) canister holds more waste but isn't "hotter" than smaller one.
Again, I am not implying that the design is stupid. I might be ignorant about many other design constrains and considerations affecting the design, such as thermal energy dissipation, resistance to damage when dropped, etc.
|Oct20-11, 02:32 PM||#6|
The waste is in solid form. The canister is more for handling, and not so much for shielding. If the shielding is built into the canister, then one has to build heavier/stronger handling equipment, e.g., crane, support structures, etc for handling or storing the canisters.
The overpack (cask) is built to provide the appropriate shielding, which is set according to expected exposure levels if someone spent a certain amont if time in the vicinity of the cask.
The canister and overpack (cask) or storage vault provides sufficient shielding.
Those designing the canister/overpack system have decided an optimal distribution of shielding mass between the canister and other shielding. There are thermo-mechanical and material considerations as well for the canister and the overpack cask.
|Nov5-11, 07:45 PM||#7|
Thanks guys! My presentation went well, and my paper should be fine (due monday).
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