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Last Updated: Oct 8, 2008 - 12:14:55 PM |
WASHINGTON — Relying on highly enriched uranium to produce medical
isotopes leaves the United States vulnerable to acts of nuclear
terrorism and a drastic shortage of one crucial material in coming
years, experts warned yesterday (see GSN, June 19, 2006).
As there is no reasonable alternative to using technetium 99m for a
widespread cardiac diagnostic test, the answer to these risks lies in
employing facilities that produce the nuclear isomer without also
creating a proliferation threat, they argued.
Four non-U.S. companies use highly enriched uranium to produce 95
percent of the global supply of technetium 99m, said Andrew Einstein, a
clinical medicine professor at Columbia University in New York.
The United States each year sends 20 kilograms of weapon-grade uranium
to a reactor at Chalk River, Ontario, where it is used to create much
of the U.S. supply of technetium. The problem is that the waste
produced through this work retains 95 percent of the original highly
enriched uranium, creating the danger that it could be put to bad uses
in the wrong hands.
There are increasing signs that terrorist organizations hope to use an
improvised nuclear weapon, said Cristina Hansell, director of the Newly
Independent States Nonproliferation Program at the James Martin Center
for Nonproliferation Studies. Their intent is to craft a devastating
weapon rather than a less-lethal radiological “dirty bomb,” she said.
“For that sort of device, highly enriched uranium is the material of
choice. Plutonium is a fissile material but it [takes] a lot more
complex technology to create a device that would make that explode
efficiently,” Hansell said during a Capitol Hill discussion organized
by the American Association for the Advancement of Science. “Using
that simple gun-type device you need highly enriched uranium.”
Terrorists are unlikely to enrich uranium themselves, so they would
have to find an available source, Hansell said. Civilian sites around
the world contain roughly 50 metric tons of weapon-grade uranium and
generally have lower levels of security than military sites, she said.
The amount of material needed for a weapon would drop as the enrichment
level increased. Major producers of technetium use material that is
enriched to 93 percent, “easily weapons-useable material,” according to
Hansell.
There has been significant progress around the world in converting
research and other reactors to using low-enriched uranium, which would
not provide fuel for nuclear explosions, Hansell said (see GSN, Oct.
3). However, “the portion of HEU that’s going to medical isotopes is
increasing as these other uses are decreased and more and more medical
isotopes are needed,” she added.
That need is growing even as the supply of technetium faces significant
drop-offs in the next few years, Einstein said. The 51-year-old
National Research Universal reactor at Chalk River is not expected to
last beyond 2014; Canada terminated the project for a replacement
facility and no new plant is anticipated, he said.
Atomic Energy of Canada Ltd., which operates the Chalk River site, did
not respond by deadline to a request today for comment.
Meanwhile, the Dutch reactor that is the United States’ second-highest
supplier of the parent compound of technetium shut down in August and
will resume operations no earlier than this month. The subsequent
shortage of technetium in the last two months in Europe and the United
States “is really a harbinger for the future,” Einstein said.
There are no good options for conducting the stress tests used to
diagnosis heart problems without the isomer, he said. The four
potential alternatives have a variety of drawbacks, including an
increased potential for causing cancer in patients, failing to detect
some cases of cardiac disease and death due to the invasive nature of
one procedure. Possible Answers
There are potential legislative responses to this twinned terrorism and
medical threat, said Alan Kuperman, a public affairs professor at the
University of Texas at Austin. He said, though, that Washington’s
record to date is mixed.
The “original sin” of U.S. HEU proliferation was the Atoms for Peace
program that in the 1950s began providing weapon-grade uranium to other
nations for reactor fuel and medical isotope production, according to
Kuperman. In some years through the 1970s, the United States sent 3
tons of uranium to other nations, enough for “dozens, dozens, dozens”
of weapons, he said (see related GSN story, today).
“We exported this stuff, bomb-grade uranium, like doughnuts or
something. It’s just remarkable,” he said.
Washington began to reverse the trend in the 1970s through a program to
produce low-enriched uranium fuel that would meet the same civilian
needs without the threat of being used in weapons. Some existing
reactors were converted for LEU use while new plants were built with
that specification.
Among those to resist the effort were producers of medical isotopes,
Kuperman said.
The 1992 U.S. Energy Policy Act set three conditions for export of
bomb-grade uranium to any reactor — the facility at the time could not
be capable of using low-enriched uranium, it had agreed to make the
switch as soon as possible, and the U.S. government was assisting the
conversion effort.
That legislation contributed to a major decline in U.S. weapon-grade
uranium exports, but it was undone by a 2005 bill that eliminated the
13-year-old restrictions, Kuperman said (see GSN, July 29, 2005).
Lawmakers in Washington “rolled over” for the Canadian reactor that was
reluctant to modify its fuel, he said.
“They resisted conversion basically because it was inconvenient. A
little bit of cost, but mainly, 'It ain't broke, don't fix it,’”
Kuperman said.
So Canada ended its LEU conversion plan for the Chalk River site and
U.S. exports of highly enriched uranium now appear to be again on the
rise, “potentially to continue in perpetuity,” he said.
While the later bill made it easier to export highly enriched uranium,
the amount actually shipped by the United States has not increased
significantly, said Nuclear Regulatory Commission spokesman Dave
McIntyre: “It’s just a function of demand.” Specific figures were not
immediately available.
There are a number of options to address the situation, according to
Kuperman, including restoration of the 1992 HEU export regime.
The government could also support development of a U.S. technetium
production capacity that would involve low-enriched uranium, Kuperman
said. Representatives from the University of Missouri and the
power-generation firm Babcock & Wilcox indicated at the discussion
that their firms could together supply 100 percent of the necessary
U.S. supply of technetium 99m.
However, both would need some form of help from the government. For
the university, it would be up to $40 million in startup costs. The
private firm would prefer to handle the capital but would look for
assistance on dealing with waste and the regulatory process.
Additionally, Congress could establish “preferences” for medical
isotopes that are produced through use of low-enriched uranium rather
than its weapon-grade counterpart, Kuperman said. That could come
through temporary subsidization of LEU processes or through
prohibitions on use of HEU-made isotopes if there is an LEU-based
alternative.
“In the long run I think we won’t have any production of isotopes with
HEU, and so we could phase out the subsidy,” Kuperman said. “But In
the short run, we should give an advantage to the technology that is
not vulnerable to nuclear terrorism.”
Source:Ocnus.net 2008
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