US National Academy of Sciences. Analysis of cancer risk in populations near NPP 3 rd Committee Meeting Atlanta, Georgia.

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1 Dose reconstruction in the epidemiologic study of the possible effect of ionizing radiation deriving from the operation of Spanish nuclear power plants and fuel cycle facilities US National Academy of Sciences Analysis of cancer risk in populations near NPP 3 rd Committee Meeting Atlanta, Georgia. May 23 rd 2011 Lucila M. Ramos Deputy Director for Environmental Radiation Protection. CSN

2 Dose reconstruction in the epidemiologic study of the possible effect of ionizing radiation deriving from the operation of Spanish Nuclear power plants and fuel cycle facilities Contents 01. Epidemiologic study: origin and scope 02. Exposure indicator: Effective dose 03. Assessment of doses due to operation of facilities 04. Assessment of doses due to natural radiation 0.5 Dose assessment results 0.6 Publications

3 01.1 Epidemiologic Study: Origin 2005: Request from Parliament, echoing a social demand regarding the impact of nuclear facilities on the health of the population Carlos III Health Institute: Analysis of the possible effect of NPPs & FCFs on the health of the population living in their vicinity Nuclear Safety Council: Assessment of the history of exposure of the population to artificial and natural radiation Setting up an Advisory Committee to guarantee independence and transparency 2006: Agreement between Carlos III Health Institute and CSN 2006: Constitution of the Advisory Committee, Members: Health authorities, associations of municipalities neighboring NPP, operators, environmental organizations, trade unions, experts in radiobiology, radiation protection and epidemiology, as long as CSN and ISCIII Function: Independent oversight regarding criteria and methodology applied, analysis of results and diffusion of the Study

4 01.2 Epidemiologic Study: Scope Facilities: Spanish Nuclear Power Plants and Fuel Cycle facilities In operation, final Shut down, decommissioning Areas of study: All municipalities located Within a 30 km radius of each facility (Influence areas) Between 50 y 100 km around facilities (Control areas) Within two areas of 30 km radius, with low and high natural radiation levels respectively Time period: From 1975 until 2003

5 01.3 Spanish nuclear power plants and fuel cycle facilities Facility type Power / Start-up Shut-down/ Location Capacity Decommission Nuclear power plants (MWe) José Cabrera PWR (W) Guadalajara Santa Mª de Garoña BWR (GE) Burgos Vandellós 1 GCR (F) Tarragona Almaraz, Group I PWR (W) Cáceres Almaraz, Group II PWR (W) Cáceres Ascó, Group I PWR (W) Tarragona Cofrentes BWR (GE) Valencia Ascó, Group II PWR (W) Tarragona Vandellós II PWR (W) Tarragona Trillo PWR (KWU) Guadalajara Fuel cycle facilities Andújar uranium mill t/a U 3 O Jaén Lobo-G uranium mil 32 t/a U 3 O Badajoz Elefante uranium mill 130 t/a U 3 O Salamanca Juzbado fuel assenbly factory 400 t/a 1985 Salamanca El Cabril LILW repository 180,000 m Córdoba Quercus uranium mill 950 t/a U 3 O Salamanca

6 01.4 Spanish nuclear power plants José Cabrera NPP Garoña NPP Vandellós I NPP Almaraz NPP Ascó NPP Cofrentes NPP Vandellós II NPP Trillo NPP

7 01.5 Spanish fuel Cycle Facilities EL CABRIL LILW repository JUZBADO fuel assembly factory QUERCUS uranium mill ELEFANTE uranium mill LOBO-G uranium mill

8 01.6 Facilities and areas of Study Garoña NPP Juzbado Fuel Plant Elefante - Quercus Uranium mills Trillo NPP José Cabrera NPP Ascó NPP Vandellós I-II NPP Almaraz INPP Lobo G Uranium mill Cofrentes NPP El Cabril repository Andújar Uranium Mill National Natural Radiation Map (MARNA): Areas 30, 50 and 100 km in radii around the Spanish NPP and FSF sites. Selected areas with low and high natural radiation outside the influence of facilities

9 01.7 Nuclear Safety Council: Reconstruction of the history of exposure of the population in the vicinity of both nuclear power plants and fuel cycle facilities due to radioactive releases during normal operation and to natural radiation Carlos III Health Institute: Epidemiologic study of the possible health effect of ionizing radiation arising from the operation of nuclear power plants and fuel cycle facilities on cancer mortality in Spain

10 02 Exposure Indicator: Effective Dose Provides clear benefits in the case of broad scope and wide spectrum studies such as the Spanish study, aiming at identifying possible apparent associations that, where existing, should be later analyzed following estimation of absorbed doses Consideration was given to the limitation of using effective dose in epidemiological studies, since it provides average exposure not suitable for quantitative risk assessment ICRP 2007 Recommendations indicates that the use of effective dose is inappropriate for epidemiologic studies ICRP considered, after a CSN consultation, that studies based on effective dose could be useful for identifying apparent correlations that should be the subject of more detailed studies if found. It was decided, with the participation of the Advisory Committee, to use the effective dose as exposure indicator in the context and with the limitations of the present study

11 Assessment of doses due to operation of facilities. Methodology INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Effective dose assessment: Direct dosimetric control of the population not feasible Results of environmental monitoring programs not used Generally below detection limits Application of physical-mathematical models Describe the behavior of the radionuclides present in the discharges of facilities in the different elements of the ecosystems Internationally recognized methodology International Atomic Energy Agency Safety Report Series Nº 19. IAEA, 2001 European Union Radiation Protection 129 (EU,2002) US NRC Regulatory Guide Site specific data (realistic approach)

12 03.2 Assessment of doses due to operation of facilities. Methodology Total effective dose: Sum of dose due to every radionuclide in every pathway = p i D a U a, pci, pfcda, i, p D a : Annual effective dose to the individual of age group a (Adult) [μsv/year] U a,p : Usage rates of exposure pathway p [m 3 /y, kg/y, s/y] for age group a C i,p : Concentration of radionuclide i in exposure pathway p [Bq/m 3, Bq/kg, Bq/m 2 ] DCF a,i : Effective Dose Conversion Factor for each age group a, radionuclide i and exposure pathway p [µsv/bq, µsv m 2 /(Bq s)]

13 INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Assessment of doses due to operation of facilities. Methodology Source term: Point-like source assumed, except uranium mills where extensive sources have been considered for tailing piles (US-NRC RG 3.51) Gamma external exposure to noble gases US NRC RG US-EPA, 2002 Federal Guidance Report-13 (DCFs) Atmospheric transport models: Standard Gaussian diffusion plume, total reflection at ground level, radioactive decay and ground deposition Aquatic dispersion model Assumes complete and instantaneous mixing downstream of the discharge point, except: Sea shore sites where a 370m strip along coast is considered Discharges to water reservoirs where source/sink model is applied

14 03.4 Assessment of doses due to operation of facilities Exposure pathways

15 03.5 Assessment of doses due to operation of facilities Exposure pathways Gaseous Effluents External exposure to radioactive cloud ground surface deposits Internal exposure Ingestion of vegetables Leafy vegetables Non-leafy vegetables, potatoes Cereals Ingestion of animal products Milk (cow and goat) Meat (beef, pork, ) Inhalation Liquid Effluents External exposure to shoreline/river bank deposits Internal exposure Ingestion of drinking water Ingestion of aquatic food Fish (sea/river) Shellfish Ingestion of food irrigated with contaminated water Vegetables Animal products Milk Meat

16 Assessment of doses due to operation of facilities. Data INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Municipalities in the area of 30 km around each facility Annual discharges of liquid and gaseous effluents from each facility Effluent control programs part of operation permits TS/ODCM-USA NRC model: GL-89-01/NUREG.1301/02 Implemented by owners Regulatory control: Evaluation of data: Monthly/annual reports, Inspection/audit (analysis of samples) Independent environmental monitoring programs. ELGA data base (1985): Comparative studies, analysis of trends All data cross checked with owners for the epidemiologic study

17 03.7 TYPE OF RELEASE Batch Waste Release Continuous Releases Waste Gas Storage Containment Purge or Vent Building Ventilation All previous Gaseous Emissions Radioactive effluents sampling and analysis program SAMPLING FRECQUENCY Prior to Each Batch Prior to One Batch/Month Prior to Each Batch Prior to Each Batch Weekly Grab Sample Monthly Grab Sample Weekly Grab Sample Weekly Grab Sample Prior to Each Tank Grab Sample Prior to Each Purge Grab Sample Monthly Grab Sample Continuous Continuous MINIMUM ANALYSIS FRECQUENCY Radioactive Liquid Effluents Prior to Each Batch TYPE OF ACTIVITY ANALYSIS Principal Gamma Emitters LOWER LIMIT OF DETECTION (Bq/m 3 ) / KEY RADIONUCLIDE Co-60 1E+04 Cs-137 1E+04 Fe-55; Ni-63 (2) Monthly Dissolved and Entrained Gases (Gamma Emitters) 3,7E+05 Composite (1) Gross Alpha 1E+03 Monthly H-3 1E+05 Quarterly Composite (1) Sr-89, Sr-90 Sr-90 1E+03 Weekly Composite (1) Principal Gamma Emitters Co-60 1E+04 Cs-137 1E+04 Fe-55; Ni-63 (2) Monthly Dissolved and Entrained Gases (Gamma Emitters) 3,7E+05 Monthly H-3 1E+05 Composite (1) Gross Alpha 1E+03 Quarterly Composite (1) Sr-89, Sr-90 Sr-90 1E+03 Radioactive Gaseous Effluents Prior to Each Tank Principal Gamma Emitters (Noble Gases) Kr-85 1E+04 Prior to Each Purge Principal Gamma Emitters (Noble Gases) Kr-85 1E+04 Monthly H-3 1E+03 Monthly Principal Gamma Emitters (Noble Gases) Kr-85 1E+04 Monthly H-3 1E+03 C-14 1E+01 Weekly Charcoal Sample Iodines I-131 2E-02 Weekly Particulate Sample Monthly Composite Particulate Sample Quarterly Composite Particulate Sample Principal Gamma Emitters Co-60 1E-02 Cs-137 3E-02 Gross Alpha 1E-02 Sr-89, Sr-90 Sr-90 2E-02

18 Assessment of doses due to operation of facilities. Data INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Site specific parameters Hydrological: flow rate, transit time from the discharge channel to drinking water supply intake and other parameters Meteorological: unitary dilution and deposition factors Land and water usages in the area (agriculture, livestock, water intake for public supply) Population habits (recreational, sport) Food consumption rates Specific study Diet and nutritional habits of the Spanish population. (CSN, 2002) Generic data Breathing rates: ICRP Publication 71. (1996) Exposure time to shoreline deposits: Radiation Protection 72 (EU, 1995) Drinking water ingestion rates ICRP Publication 23. (1975)

19 04 Assessment of doses due to natural radiation Exposure indicator: Effective Dose Scope: Municipalities around facilities, control areas and 2 additional zones Exposure pathways External radiation: Cosmic radiation, terrestrial gamma radiation Internal contamination Inhalation (radon and toron) Internal exposure due to food and water consumption Internationally recognized models UNSCEAR 2000 Sources and effects of ionizing radiations Data From different CSN projects (Radon) and and other studies published by several research groups or national/international average data (UNSCEAR)

20 Dose assessment. Uncertainties INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Effective doses estimated using best estimate values for the input parameters giving results generally below 10 µsv/y: Uncertainties study not justified (RP-129, EU 2000) Concerning methodology, results are considered not to underestimate doses in more than one order of magnitude. (IAEA, 2001) Due to the general conservatism in models and generic parameters, it is most likely that doses are over estimated The most important source of uncertainty comes from input data and assumptions Big effort in gathering site specific data, but generic data used when no specific information available (site-by-site approach) For natural radiation, besides uncertainties associated to the inherent spatial variations (around 30%), there are big uncertainties in dose conversion factors (100 % for radon inhalation)

21 Dose reconstruction. Some considerations INSTALACIONES Y FUENTES RADIACTIVAS. Normativa Study without precedents, performed between Compilation/revision of historic data of discharges 10 NP Reactors and 6 FC Facilities, from 1959 to 2003 Estimation of annual and cumulative doses due to discharges In 505 municipalities for every year considered Duplicate assessment: Calculations by CSN and owners independently, (same methodology and data but different codes) Supervised by Advisory Committee experts Compilation of available national data of radon concentrations in dwellings. Specific measurements campaigns Annual dose estimations due to natural radiation in more that 1100 municipalities 505 municipalities around facilities 477 municipalities in the areas between 50 and 100 km 140 municipalities in the zones with high and low natural radiation levels Supervised by Advisory Committee experts

22 05.3 Assessment of doses. Results Total effective doses due to operation of facilities and natural radiation: Estimated yearly for the population of every municipality within 30 km of the each facility since operation beginning until 2003 A single annual dose value for each municipality around the facilities, control areas and 2 additional zones, since natural radiation is assumed not to change with time Represent the average annual total effective dose received by a representative individual of each municipality It is not the real dose received by individuals, but the best estimate value of that dose

23 E E E E E E E E E-07 Cofrentes Nuclear Power Plant. Estimated doses in all municipalities in 2003 (msv/y) Yatova Zarra GASES LÍQUIDOS R. NATURAL Balsa de Ves Carcelen Casas de Ves Villa de Ves Villatoya Ayora Bicorp Cofrentes Cortes de Pallas Dos Aguas Jalance Jarafuel Macastre Millares Quesa Teresa de Cofrentes Alatoz

24 05.5 Cofrentes NPP. Dose evolution in the most exposed municipality (msv/y) 1,0E+01 1,0E+00 1,0E msv Natural Radiation 1 msv Legal Dose Limit 0.1 msv Discharge Limits 1,0E-02 1,0E-03 1,0E-04 Cofrentes (GAS) 1,0E-05 1,0E-06 1,0E-07 Cofrentes (LIQ) Año

25 05.6 Cofrentes NPP Effective dose for all municipalities

26 05.7 Artificial (cumulative) and natural (annual) doses ranges in the municipalities around the facilities

27 INSTALACIONES Dose reconstruction. Y FUENTES Conclussion RADIACTIVAS. Normativa Radiological impact of installations Estimated cumulative effective doses due to the operation of facilities are very low Maximum value 350 µsv (Annual dose limit 1000 µsv) Estimated annual effective doses due to the operation of facilities are in the range of and 73.4 µsv. Values present a big variability between municipalities of a given site and between different sites Radiological impact due to natural radiation Estimated annual effective doses due to natural radiation are in the range of 250 µsv/and 20.1 µsv/año. Dose values present less variability Estimated doses due to the normal operation of facilities represent a very small fraction of doses due to natural radiation

28 06 Publication of results Realistic retrospective dose assessment to members of the public around Spanish nuclear facilities

29 Thank you