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Decommissioning in Italy
(The Decommissioning and Dismantling of
Nuclear Facilities in OECD/NEA Member Countries - Italian National
fact sheet by ANPA)
1 -
Present Status of the Italian nuclear installations
2 -
Legal and Regulatory Framework
3 -
The initial strategy
4 -
Government strategy change and the role of SOGIN
5 -
Current programs and main issues
6 -
The management of radioactive wastes and spent
fuel
7 -
The National repository
8 -
Funding
5. Current programs and main
issues
5.1 Some aspects and
key points
Sogin has revised all decommissioning
programs according to the Government's guidelines, with the target to
reach the complete radiological release of all NPP’s sites within
2020.
ENEA has also developed a program in compliance with the Government
indications, ending in 2015. However, SOGIN, after taking over the
licenses in 2003, is evaluating any program change that could take
advantage of all synergies possible in a totally integrated
decommissioning system.
The new plan defines the schedule of main activities on each site,
with a view to the optimisation of costs and resources of the entire
Italian system. As for the techniques of decontamination and
dismantling that will be used, detailed technical aspects in some
cases have still to be defined. Considering in particular the level of
contamination and other technical and economic factors, different
procedures for chemical and/or mechanical decontamination for main
components are under evaluation.
Difficulties related to the decommissioning programs are mainly
connected to the facts that all NPP's are of different technologies,
all of them are stand alone, they are quite far each from the other
and the local social context is quite different. The same difficulties
apply to Fuel Cycle installations.
All decommissioning activities are performed complying with conditions
and technical specifications laid down in the decommissioning license.
The systems, components and equipment relevant to safety and radiation
protection are subject to a general regime of technical specifications
and surveillance tests, either specified in the decommissioning
license or, possibly, in the operation licence for the sections still
in force. Moreover special technical requirements applicable to new
equipment or new specific operations are laid down on a case by case
basis after a preliminary safety and radiation protection analysis.
The concept also applies to the use of new technologies, for which
adequate experimental tests are often required. Special emphasis is
given to radiological characterisation of the installation and of
materials.
APAT supervises decommissioning operations and carries out inspections
to verify compliance with technical specifications concerning safety
and radiation protection.
Main uncertainties connected with the implementation of the program
are linked with the specification for the repository, and with the
date of its actual availability.
5.2 Clearance Levels
The definition of clearance levels is
particularly relevant, since the decommissioning of a nuclear plant
produces a relevant amount of solid materials, most of which presents
very low levels of radioactivity, such to allow their reuse or
disposal as conventional wastes.
It has also a strong impact on:
- the characterisation of the plants,
- the decontamination processes,
- the methods of materials control,
- the amount of material to ship
to the future national repository.
A general criterion is in force in
Italy for unrestricted release. Radioactive materials can be
unconditionally released from regulatory control if the radionuclides
concerned comply with both a concentration and a radioactive half life
threshold:
- C ≤ 1 Bq/g, and
- half-life < 75 days.
If both conditions above are not
complied with, a specific authorisation is required for releases,
reuse and recycle of the materials concerned. The authorisation is
given on the basis of an analysis which has to demonstrate compliance
with the basic 'below regulatory concern' criterion below, both
conditions of which must be met:
- Effective dose ≤ 10 µSv/year, and
- either Effective collective dose ≤ 1
man·Sv/year or the analysis demonstrates that exemption is the
optimum option.
An example of application of the above
criteria for solids is the recent authorisation for decommissioning of
the Caorso NPP. The thresholds for the various nuclides are shown in
the following table.
|
Nuclide |
Metal material |
Building rubble |
Other materials |
| |
Bq/g |
Bq/cm2 |
Bq/g |
Bq/cm2 |
Bq/g |
|
H3 |
1 |
10.000 |
1 |
10.000 |
0.1 |
|
C14 |
1 |
1.000 |
1 |
1.000 |
0.1 |
|
Mn54 |
1 |
10 |
0.1 |
1 |
0.1 |
|
Fe55 |
1 |
1000 |
1 |
10.000 |
0.1 |
|
Co60 |
1 |
1 |
0.1 |
1 |
0.1 |
|
Ni59 |
1 |
1.000 |
1 |
10.000 |
0.1 |
|
Ni63 |
1 |
1.000 |
1 |
10.000 |
0.1 |
|
Sr90 |
1 |
1 |
1 |
100 |
0.1 |
|
Sb125 |
1 |
10 |
1 |
1 |
0.1 |
|
Cs134 |
0.1 |
1 |
0.1 |
1 |
0.1 |
|
Cs137 |
1 |
10 |
1 |
1 |
0.1 |
|
Eu152 |
1 |
1 |
0.1 |
1 |
0.1 |
|
Eu154 |
1 |
1 |
0.1 |
1 |
0.1 |
|
α emitter |
0.1 |
0.1 |
0.1 |
0.1 |
0.01 |
|
Pu241 |
1 |
1 |
1 |
10 |
0.1 |
For metal scrap, ah hoc technical specifications have been provided
for, with a view to controlling the final destination of the metal
material meant for foundry; for instance, the foundry will be required
to mix the metal scrap from the plant with uncontaminated scrap in a
1/10 ratio.
No specific criteria are provided for in the Italian legislation for
the release of regulated facilities and/or sites, although the general
criteria stated above obviously apply. As an aid to determining
release levels the recommendations of the European Commission's
Publication 113 can be used.
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