Solid Radioactive Waste Strategy Report.pdf - UK EPR

EPR UK
N° NESH-G/2008/en/0123
REV. A PAGE 90 / 257
8.1.2.1 Radiological Characteristics After 60 Years Of Operation
8.1.2.2 Primary Circuit
Contamination
The expected radionuclide contamination in components arising during normal operation has
been derived by the designer. This has been based on up to date operational experience
from French and German reactors. The figures have been revised to reflect the advanced
technical, geometrical and design features of the UK EPR.
During plant operation, corrosion products can deposit on the inner surface of pipes and
components, and build up as loosely bound deposits and/or a solid contamination layer.
The forecasted EPR corrosion product specification is given in Table 20.
TABLE 20: RADIOACTIVE DEPOSIT OF CORROSION PRODUCTS ON INNER SURFACE
OF THE MAIN COOLANT LOOPS
Nuclide
Primary piping
Hot/Cold legs (Bq/m 2 )
Steam Generators
(Bq/m 2 )
Fe-59 7.0E7 to 2.0E8 5.0E7 to 1.2E8
Mn-54 2.5E8 to 4.0E8 6.5E7 to 1.3E8
Co-58 3.0E9 to 5.2E9 2.5E8 to 2.6E9
Co-60 5.0E8 to 9.8E8 2.5E8 to 5.0E8
Prior to dismantling, the primary circuit will be chemically decontaminated. The contamination
will be collected on ion exchange resins. The contamination data for the primary circuit has
been used for the characterisation of the waste (ion exchange resins) produced during the
full decontamination of the primary circuit.
The entire primary system to be decontaminated has an overall volume of about 395 m 3 and
a total surface area of 15800 m 2 . The steam generators make the greatest contribution to
the overall surface area (14000 m 2 ).
Note: These figures exclude component replacement.
Activation
Activation only occurs to primary circuit components exposed to the neutron flux from the
reactor core. These components are illustrated in Figure 25.