SRS Completes Neptunium Work, Continues
to Support NASA
Although SRS no longer makes plutonium-238,
it still continues to support the nation’s space program
through production of neptunium-237 oxide.
The last of this neptunium – which
also represents the last of the United States’ neptunium
inventory – has been safely and successfully converted
from a liquid into a more stable powder form and will be shipped
to Idaho in the coming weeks. There, it will be loaded as
a target into a reactor to produce plutonium-238, which will
be used in NASA’s deep space probes. This material will
satisfy NASA’s needs for the next 20-30 years.
Pu-238 has a unique combination of high heat
output and long life, allowing designers to keep weight at
a minimum and still have a power supply that is effective
for many years. Where solar power is not practical, NASA uses
Pu-238 as a heat source in Radioisotopic Thermoelectric Generators.
These convert heat to electrical power to operate various
deep space vehicles, such as the Galileo, Ulysses, Cassini,
and more recently the New Horizons mission to Pluto. Small
heat generators have also been used to keep the axle lubricant
of the Mars Rovers from freezing.
Neptunium solution was generated at SRS through decades of
reactor fuel cycles and H Canyon/HB Line operations. It was
stored in liquid form since the 1980s and then, beginning
in 2004, was converted into oxide, or powder, in HB Line.
Those conversions were completed in early November, and the
material was packaged and shipped from H Area to K Area.
Although H Canyon continues to operate, no
new neptunium materials will be generated at sufficient amounts
to be useful, said Fred Dohse, who directs nuclear materials
operations for SRNS.
“The neptunium inventory was produced
by processing our recycled Site spent nuclear fuel, which
had a high concentration of this material,” he said.
“The material we will be processing in the future doesn’t
have nearly the amount of neptunium in it that our Site fuel
had.”
SRNS President and CEO Chuck Munns said the
employees deserve the credit for the safe success of this
long-running campaign.
“This is hard work, and it’s
important to the Site and the nation to stabilize these materials,”
he said. “Employees in H Canyon, HB Line, the analytical
laboratories, and K Area deserve a lot of credit for executing
such a long-term project safely and successfully.”
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