Definition of clearance levels for the release of radioactively contaminated buildings and building rubble

European Commission Directorate-General For The Environment

Description

Final Report
Nuclear energy and safety

Sujets

• Heavy equipment (construction)
• Radioactive decay
• Recycling
• Human decontamination
• Radioactive waste

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-THE-ENVIRONMENT
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 2 Mo

Extrait

European Commission
Radiation protection 114
Definition of clearance levels
for the release
of radioactively contaminated
buildings and building rubble
Final report European Commission
Radiation protection 114
Definition of clearance levels for the release
of radioactively contaminated buildings and building rubble
Final report
Contract No Cl/ETU/970040
carried out on behalf of the
European Commission, Environment Directorate-General
Dr A. Deckert
Dr S. Thierfeldt
Dr E. Kugeler
Dipl.-Ing. I. Neuhaus
Brenk Systemplanung, Aachen
5 May 1999 A great deal of additional information on the European Union is available on the Internet.
It can be accessed through the Europa server (http://europa.eu.int).
Cataloguing data can be found at the end of this publication.
Luxembourg: Office for Official Publications of the European Communities, 2000
ISBN 92-828-9170-4
© European Communities, 2000
Reproduction is authorised provided the source is acknowledged.
Printed in Belgium Foreword
The European Commission has published guidance of the Group of Experts established
under Article 31 of the Euratom Treaty on the clearance of buildings and building rub­
ble arising from the dismantling of nuclear installations (Radiation Protection N° 113).
The technical basis for these recommended criteria was provided by a consultant (Brenk
Systemplanung, contract Cl/ETU/970040) as input to the discussions of a working
party of the Group of Experts.
The present publication of the consultants report is important in view of ensuring full
transparency of the approach and traceability of the values. It will in addition facilitate
similar work carried out in Member States or outside the European Union and contrib­
ute to the harmonisation of clearance levels proposed internationally.
S. Kaiser Contents:
1. INTRODUCTION 1
2. BUILDINGS AND BUILDING MATERIAL FROM NUCLEAR INSTALLATIONS 3
2.1 Potential Quantity of Buildings and Building Material 4
2.1.1 Installations in Germany
2.1.2s in France 6
2.1.3s in Europe in general 10
2.2 Recycling and Disposal Options for Building Rubble and Buildings 13
3. ASPECTS INFLUENCING THE DOSE CALCULATIONS5
3.1 General Aspects
3.2 Radionuclides6
3.3 Dose Coefficients7
3.4 Relationship between Surface and Bulk Activity 19
3.5 Averaging Areas and Masses 20
4. RADIOLOGICAL ANALYSIS1
4.1 General Approach to Calculation of Clearance Levels for Buildings 2
4.2 Clearance of Buildings for Continued Use as a Non-Nuclear Facility3
4.2.1 External γ-dose
4.2.2 Inhalation dose5
4.2.3 Dose from secondary ingestion6
4.2.4 Skin dose ." 27
4.2.5 Exposure to Radon8
4.3 Clearance of Building Rubble and Buildings for Demolition 29
4.3.1 Source term and radiological considerations
4.3.2 External γ-dose 3
4.3.3 Inhalation dose3
4.3.4 Ingestion dose
4.3.5 Skin dose
4.4 Considerations to the Collective Dose
4.4.1 Collective dose from the reuse of buildings 40
4.4.2e dose from cleared building rubble
5. DOSE CALCULATIONS AND CLEARANCE LEVELS1
5.1 Results of the Dose Calculations
5.2 Derivation of Clearance Levels 5
5.2.1 Surface specific clearance levels
5.2.2 Massce levels2
5.2.3 Applicability of the clearance levels to other types of installations 5
5.2.4 Clearance levels in relation to exemption values3 6. LITERATURE 57
APPENDIX:
1. DERIVATION OF THE FORMULA FOR THE RADIONUCLIDE
CONCENTRATION IN DRINKING WATER 1
2. DOSE COEFFICIENTS USED IN THE CALCULATIONS 5
3. DATA FOR THE NUCLEAR INSTALLATIONS 12
List of tables:
Table 2-1: Shut down nuclear power plants in France 7
Table 2-2: Expected masses for level 2 and 3 dismantling of nuclear power plants separated
according to their specific activity A (in Mio Mg) 8
Table 2-3: Assumptions for the estimation of waste masses in Europe (for detailed
information see appendix A) 11
Table 3-1 List of radionuclides with short-lived progeny assumed to be in equilibrium 17
Table 4-1: Building reuse, parameters for the external exposure scenario 24
Table 4-2:g reuse,s for the inhalation scenario6
Table 4-3: Building reuse, parameters for the ingestiono7
Table 4-4:g reuse,s for the skin dose scenario8
Table 4-5: Buildings for demolition and building rubble: parameters for the external exposure
scenario 32
Table 4-6: Buildings for demolition and building rubble: parameters for the external exposure
scenario4
Table 4-7: Buildings for demolition and building rubble: parameters for the ingestion
scenarios
Table 4-8: Buildings for demolition and building rubble: parameters for the skin dose scenario 39
Table 5-1: Results of the dose calculations for the reuse scenarios for buildings 4
Table 5-2:s of the surface specific dose calculations for building demolition with
recycling of the building rubble 45
Table 5-3: Results of the mass specific dose calculations for recycling building rubble8
Table 5-4: Derived clearance levels for buildings and building rubble 54
APPENDIX:
Table A2-1: Equilibrium constants (KJ) from [SHE 90] for sandy soil 6
The dose coefficients (DC) including nuclides in secular equilibrium at the time of Table A2-2:
clearance (t=0), the time (tmax) within the first 100 years at which the dose
coefficients reach a maximum due to the radioactive progeny and the dose
coefficient at this time DC(t=tmax) 7
Table A2-3 Dose coefficients used in the calculations, which include the radionuclides in
secular equilibrium and the progeny within the first 100 years after clearance 9
Table A3-1 Operating nuclear power plants 12
Table A3-2 Shut down nuclear power plants6
Table A3-3 Research reactors8
Table A3^1 Fuel cycle facilities9 1 - Clearance levels for buildings and rubble
Final Report
1. INTRODUCTION
Radiation protection requirements pertaining to the operation of nuclear installations in the Member
States of the European Union (EU) are established at a national level, whereby national legislation
is bound by the Euratom Treaty to comply with the general EU standards: "The Basic Safety Stan­
dards for the Health Protection of the General Public and Workers against the Dangers of Ionizing
Radiation" (BSS). A revised Basic Safety Standards Directive was adopted in May 1996 and must
be implemented in national legislation by May of the year 2000 [CEU 96].
One of the requirements in the new Standards is that the disposal, recycling and reuse of material
containing radioactive substances is subject to prior authorisation by national competent authorities.
It is stated, however, that the authorities may specify clearance levels below which such materials
are no longer subject to the requirements of the Standards. Clearance levels shall be established on
the basis of the general criteria for exemption laid down in Annex 1 of the Directive, and take into
account technical guidance provided by the Community (e.g. [EUR 98]). According to Article 5 it is
the responsibility of the competent national authorities to define the numerical values for clearance.
Thus upon decommissioning and dismantling of nuclear installations, regulatory control may be
relinquished for part of the premises or materials arising from dismantling. For example, there are
currently more than a hundred nuclear reactors operating in the EU and around 40, many of which
are research reactors, which have been shut down and are being decommissioned. This represents a
large potential for "waste" material under regulatory control, the largest portion being building ma­
terial, which is to a large degree not or only very slightly radioactive. Recycling or conventional
disposal of the rubble resulting from the demolition of the buildings or the non-nuclear use of the
buildings would avoid unjustified allocation of resources for the radioactive disposal of this low
activity waste and save valuable natural resources.
The European Commission has already published technical guidance for the clearance of items,
equipment and metal scrap in "Recommended radiological protection criteria for the recycling of
metals from dismantling of nuclear installations" (RP 89) [EUR 98]. The present report serves as
the basis for developing a similar recommendation for technical guidance for the clearance of
buildings and building material belonging to practices subject to reporting and prior authorisation as
set out in Article 2 para. 1 of the BSS. The emphasis is placed on the material from dismantling
large facilities, of which nuclear power plants will give rise to the largest quantity in the EU, but the
general nuclide specific criteria developed here are also valid for nuclear fuel cycle installations and
facilities such as isotope laboratories. The term "building" is used here in a broader sense to mean
not only buildings but also rooms, sections of buildings and building structures.
The criteria being developed in the present study only apply to practices and the material within
these practices which fall under the scope of Article 2 para. 1 of the BSS. In particular, the radio­
logical analysis in this study applies to all buildings which are part of an authorized practice. The
criteria do not apply to nat