TheBeaconMagazinev2

THE BEACON MAGAZINE | FEATURE
15
Nuclear first
on Wylfa’s last day
Amec Foster Wheeler experts have found a way to achieve huge savings
as reactors approach planned closure
and fuel transport, as the interfaces with
them were crucial.”
Wylfa 1 nuclear
power plant
When the Wylfa 1 reactor was
shut down for the last time on
the afternoon of December
30, 2015, it brought an end to the 49-year
history of the UK’s Magnox stations.
But a nuclear first was achieved that day
as well as the reactor had almost used up
all of its available fuel.
Duncan Hall, Nuclear Science and
Structural Integrity Operations Manager
at Amec Foster Wheeler’s Clean Energy
business, said: “What Magnox did, with
our support, at Wylfa has not been done
anywhere else in the world as far as we’re
aware. Usually, reactors tend to be shut
down with lots of very productive fuel still
inside. That would probably include some
fuel that was placed inside the reactor
only a few months before. This is a waste
because fuel doesn’t get to its most
reactive state until it’s been in use for
about a year.”
Needless to say, Wylfa’s precise timing
did not happen by accident. Back in 2002,
Magnox commenced initial studies into
fuel cycle optimisation at the four
remaining stations, which also included
Sizewell, Dungeness and Oldbury.
Magnox staff from engineering,
reactor physics, operations, fuel route and
commercial departments were involved in
determining the strategic options, along
with experts in fuel performance, fuel
cycle design, reactor fault studies, safety
case, and independent nuclear safety
assessment. Because the capacity for fuel
reprocessing would be a major constraint,
representatives from Sellafield were also
involved. The programme, which had not
been attempted anywhere before, was divided
up into four parallel work-streams of
reactor physics, modellers, fault analysts
and safety case authors, plus site
implementation teams, all operating to
tight timescales.
Amec Foster Wheeler’s reactor and fuel
performance, reactor physics and fuel
cycle management teams worked closely
with Magnox throughout. Duncan
explained: “Most people think this is
something just for physicists and fuel
cycle people to deal with. In fact the key to
success was to involve fuel reprocessing
The lessons from Sizewell and Dungeness
were applied by Magnox to Oldbury and
Wylfa, where more fuel efficient fuel cycles
and associated safety cases were
implemented. And when the opportunity
arose to generate electricity for longer
at Oldbury and Wylfa, these greater
efficiencies really came into their own.
At Wylfa, thanks to the transfer of fuel
from the already shut down reactor 2, the
station continued generating for another
five years without needing to order any
new fuel.
“Magnox were able to dispense with the
equivalent of four years’ fuel purchases,”
said Duncan. “And because the used fuel
was more irradiated because it had been
in the reactor for longer, it did not cost as
much to reprocess.”
As an indication of just how massive the
savings could be, it’s worth noting that a
Magnox reactor has space for more than
48,000 fuel elements. Meanwhile, the
additional generation at Oldbury and
Wylfa reaped a windfall of more than £1bn
for the British taxpayer via the Nuclear
Decommissioning Authority, Magnox’s
owners.
News of the remarkable results achieved
at Wylfa have spread around the industry
in the UK and abroad, so Duncan and his
team are now talking to other operators
about how they can achieve the same
efficiencies.
To find out more:
duncan.hall@amecfw.com