Page 342 - Beyond Decommissioning

318 Beyond Decommissioning

decommission the facilities; delicense the land; attract tenants. At Winfrith, these
three objectives are being pursued in parallel.
The United Kingdom Atomic Energy Authority’s (UKAEA’s) Winfrith site was
established in the late 1950s to design and construct prototype reactor as research
and development steps toward nuclear power generation. Approximately 485ha of
heathland were purchased. Work on the site began in 1958. Some 130ha of the pur-
chased land were enclosed within the perimeter fence. The outer land was used as a
buffer zone. The site had a central administration building with the individual reactors
situated around it. Over the years, a number of prototype reactors were constructed on
the Winfrith site. Six zero- and low-power reactors were in operation in due time,
together with the larger Dragon and Steam Generating Heavy Water (SGHWR) reac-
tor (the only Winfrith reactor providing energy to the National Grid). A number of
facilities supported the reactors including: a post-irradiation examination (PIE) facil-
ity, a fuel fabrication facility, a fissile material store, radiochemical laboratories,
workshop facilities, etc.
During the 1960s and 1970s, a good deal of world-class scientific and engineering
work was performed at Winfrith. During the 1980s, work on the site also included
some nonnuclear applications, for example, for the oil industry. At its peak, the site
employed 2000 staff.
In the early 1990s, the UK Government closed down its program of nuclear R&D,
and work started on environmental remediation (ER) of the Winfrith site beginning
with the dismantling of the nuclear facilities. The UKAEA’s role then changed to
one of environmental restoration of its sites. However, the program of environmental
restoration was planned to retain specified buildings and infrastructure for
alternative use.
The Winfrith site includes areas of heathland that are the habitat for some protected
species of flora and fauna. As such, a part of the site has been designated as a Site of
Special Scientific Interest, and has to be managed accordingly.
During the 1990s, decommissioning work was carried out on a number of facilities
at Winfrith. Brief descriptions of selected decommissioning projects are given below.
The last reactor operated by the UKAEA, the NESTOR Reactor, was shutdown in
1995. Its decommissioning began in November 1998 and was completed in January
2000. The post-operational clean out of the six reactor support laboratories was a part
of the NESTOR project. Decommissioning of the Dimple Reactor began in August
1999 and was completed (other than the external, underground dump tank facility)
in April 2000. The area is now grassed and awaiting delicensing.
The Alpha Materials Laboratory (AML) was a two-story building, first used in
1963 for the manufacture of mixed oxide fuel. The AML handled kilograms of plu-
tonium at any given time, and many tons of plutonium passed through the building
until its shutdown in the early 1990s. The dismantling commenced in 1996 and the
‘green field’ status was reached in spring 1999 (Neal, 2003). The Zero Energy Breeder
Reactor Assembly (ZEBRA) was demolished in 2006 and decommissioning
completed in 2010, with the clearance of its office block.
The Active Handling and Decontamination Building was constructed between
1962 and 1964 and was designed and built for the PIE of a wide range of reactor fuel