Solid Radioactive Waste Strategy Report.pdf - UK EPR

EPR UK
N° NESH-G/2008/en/0123
REV. A PAGE 222 / 257
13.3.2 Building layout
Interim storage facility: outside or inside a building
When the flasks are stored outside, the storage facility consists of a concrete storage pad for
the flasks which store the spent fuel. The facility would be located within a protected area of
the plant site.
The storage building consists on a storage hall which has the main characteristics: thick
concrete structure, wall thickness approximately 0.8-1.2 m, roof thickness 0.6-1 m, and one
or two naives in the building.
Doel Storage Facility, Belgium
Surry Storage Facility, US
The storage facility is designed to operate for 100 years.
Some of the reasons to prefer a building over a dry storage system are:
· An overbuilding will help to reduce the dose rates by almost eliminating skyshine dose
and also reduce direct dose. However the flask has been designed to meet any dose rate
criteria without a building;
· Nevertheless, the storage of flasks would require that the site fence were some distance
from the flasks in order to satisfy off-site dose limits;
· Having a building will protect better from weather conditions. The flask equipped with the
protective cover will also provide weather protection.
It can be noted that having a building over the dry storage system has some disadvantages
such as the impact on the natural convection heat transfer due to the effect of enclosure from
the building.
Storage building
The schematic drawing of the storage building for metallic flasks is presented below. Interim
storage of an average of 3400 spent fuel assemblies yields to about 170 to 220 flasks,
depending on the flask capacity. The approximate dimensions of the storage building are 100
m x 40 m.