Nuclear waste

[M Nivas <motnivas@YAHOO.COM>]

Greetings all,



The article below appeared this morning from

Scientific American.



I beleive this is of interest,  Enjoy - Tom 



NUCLEAR WASTE 

Scientists Voice Concerns about Yucca Mountain

Repository 



Normally, engineers can assess and improve upon the

reliability of a new technology through operation. If

a model car breaks down, the problem can be fixed

before it hits the market. But not all developers have

that luxury. In the case of geologic storage of

high-level nuclear waste, currently planned for

Nevada’s Yucca Mountain, the potential consequences of

a leak leave little room for experimental error. Such

a plan, say researchers writing in the current issue

of the journal Science, demands a much sharper

analysis of geologic and atomic-scale processes than

has been conducted thus far. For this reason, they

argue, President George W. Bush's recent decision to

recommend Yucca Mountain as a disposal site for

high-level nuclear waste is premature, and the plans

should not advance until the relevant scientific

issues have been thoroughly explored. 



The push to establish a repository at Yucca Mountain

is based on political considerations and national

security concerns, not hard science, Rodney Ewing of

the University of Michigan and Allison Macfarlane of

the Massachusetts Institute of Technology, assert.

They point to recent shifts in the design strategy to

support their view. For one, the role of engineered

barriers for the waste has increased. Originally,

Yucca Mountain was selected because of its natural

characteristics: a repository could be placed 300

meters above the water table and, presumably, kept

dry. But subsequent research results indicated that

water may actually circulate upwards through the

mountain, and near the proposed waste storage area.

Accordingly, the plan now depends on engineered

barriers, including durable drip shields that would

prevent water from carrying away radioactive material.

"By lessening the importance of geologic barriers, the

properties of the site become less important," the

authors write. "Indeed, the original concept of

geologic disposal has been turned on its ear." 



But this is hardly the only problem with the Yucca

Mountain proposal, Ewing and Macfarlane observe. Other

long-term factors, such as the influence of climate

change, the durability of the metallic waste packages,

and the impact of volcanic activity require detailed

probing as well. Yucca Mountain may yet prove to be a

good location, the researchers concede, but the

proposal warrants more thoughtful and complete

consideration before any such decision can be made.

Quoting Thomas Jefferson, they conclude, "Delay is

preferable to error." —Greg Mone 





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