Re: Yucca Mtn. This should raise some hackles

[Pat Keeney <patk@TOAD.NET>]

This popper up today as an interesting headline...note how the headline and
the facts are disconnected:)

Pat

http://www.lvrj.com/lvrj_home/2002/Aug-01-Thu-2002/news/19319084.html

Thursday, August 01, 2002
Copyright © Las Vegas Review-Journal

Study: Yucca volcano would be destructive


THE ASSOCIATED PRESS



WASHINGTON -- A volcanic eruption at Yucca Mountain could do more damage
than previously thought, possibly forcing radioactive waste from its burial
site to the surface, according to a new study.

If long-dormant volcanoes near the prospective high-level nuclear waste dump
sprang back to life, molten rock moving at up to 600 mph could fill the
repository deep beneath the Nevada desert within hours, said an article in
the July issue of Geophysical Research Letters, a publication of the
American Geophysical Union.

Intense heat and pressure could cause some canisters of spent nuclear fuel
that are to be buried at Yucca Mountain to rupture and allow radioactive
material to flow toward the surface, the article said.

"It can potentially affect a large number of waste canisters," wrote a team
of English, Dutch and American scientists that developed computer models to
assess the risk of a volcanic eruption.

Seven dead volcanoes are within 27 miles but the last eruption was 80,000
years ago. Project scientists calculate that the chance of one occurring
within the waste repository over the next 10,000 years is 1 in 70 million.

Previous government studies have said volcanic eruptions would do little
damage to the site 100 miles northwest of Las Vegas. But project scientists
who commented on a draft of the new study said it presents a potentially
useful model for evaluating what could happen if an eruption were to occur.

President Bush last week designated Yucca Mountain as the nation's lone
long-term waste repository.

----- Original Message -----
From: "Bernard Cleyet" <anngeorg@PACBELL.NET>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, August 02, 2002 4:09 AM
Subject: Re: Yucca Mtn. This should raise some hackles


> "Also, the shorter half-life means higher energy radiation, which further
> increases the danger."
>
>
> This is certainly true for Alpha decay, but I don't think so for gammas,
i.e.
> the energy of the excited state of a daughter is not easily related to the
> half life of the parent, yes?
>
> For Betas, I estimate the six order change in 1/2 life results in ~ 40 X
> increase in end point energy (assuming similar matrix elements).  In both
> cases "so what":  A sheet of paper will stop the most energetic Alphas,
and a
> few inches of concrete the Betas.
>
> bc who has measured (lab exercise) the specific activity of a nuclear
species
> (K-40) to determine its half life
>
> P.s.  Radioactive fallout intensity is ~ T^-1.2 from ~ten min. to 200 days
or
> a reduction in activity of 4* E-6; after that it is more rapid.  This is a
> result of the varying half lives of > 200 isotopes of 36 elements.  (The
> gasses krypton and xenon are not included.)    A further reduction to
1*E-9 is
> reached in 25 years.  This is a drop in the bucket considering the two
ounces
> of fission products per kiloton yield is, in gamma activity, equivalent to
> 30,00 TONS of radium in equilibrium with its daughters!!!!  (Remember one
> milligram of radium has an activity of one milliCi.)  As the shorter
isotopes
> decay the rate will approach exponential decay.  quick calc.:  initial 2
oz.
> (2.7E10 Ci) in 25 years is 270 Ci or 4.8 Ci / initial gram of fission
> products.  The power station's waste will additionally include depleted
U -- ~
> 10E9 yr. half life?   (source:  Glasstone, 'The Effects of Nuclear
Weapons"
> 1962)
>
>
> Tim Folkerts wrote:
>
> > > BTW, why are we so much more worried about shipping spent rods than
> > > fresh ones, which are being shipped all the time with no apparent
> > > controversy. There may be a good explanation for this. I just don't
> > > know one.
> >
> > I was wondering about this too, but then had an idea.  Presumably the
mass
> > & volume are similar before and after use.  However, the uranium fuel
has a
> > 1/2 life of ~10^9 years, while the waste is ~10^3 yr.  This means an
equal
> > amount of material is 10^6 more radioactive.  Also, the shorter
half-life
> > means higher energy radiation, which further increases the danger.
> >
> > Tim Folkerts
> > Department of Physics
> > Fort Hays State University
> > Hays, KS  67601
> > 785-628-4501