2009 International Nuclear Atlantic Conference - INAC 2009 Rio de Janeiro,RJ, Brazil, September27 to October 2, 2009 ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN ISBN: 978-85-99141-03-8 THE MARINE ENVIRONMENT MONITORING IN SACO PIRAQUARA DE FORA AFTER THE BEGINNING OF THE ANGRA 2 NUCLEAR POWER PLANT OPERATION Tavares, P.G., Souza, R.F. & Cardoso, S.N.M. Laboratório de Monitoração Ambiental Eletrobrás Termonuclear S.A. Rua Natal, s/n – Vila Residencial de Mambucaba 23.970-000 - Paraty, RJ [email protected] [email protected] [email protected] ABSTRACT The goal of this paper is to evaluate the environmental monitoring around the Almirante Álvaro Alberto Nuclear Power Station after the beginning the operation of Unit II, in July 2000. The Environmental Monitoring Laboratory collects several environmental samples and analyses them radiometrically to determine the presence of artificial radionuclides. In the Environmental Monitoring Laboratory, the samples are prepared and analysed following international procedures and the activities of the detectable radionuclides are obtained by gamma spectrometry. The Environmental Monitoring Laboratory analyses tritium in sea water as well. This paper will describe only the monitoring of the marine samples and the results of the measurements are compared with those obtained in pre-operational time of Angra 1 (1978 – 1982), Angra 2 (1996 – 2000) and those obtained in operational time of the units until 2008. The results show that, since 1982 until now, there’s no impact on marine environment caused by the operation of Angra 1 and Angra 2. 1. INTRODUCTION The Almirante Álvaro Alberto Nuclear Power Station (AAANPS) (Figure 1) is located in Itaorna Beach, at the Km 517 of Mário Covas Road (former Rio-Santos Road – BR-101), in Angra dos Reis, Rio de Janeiro and belongs to Eletrobrás Termonuclear S.A. – ELETRONUCLEAR. It’s formed by three units: Angra 1, a Westinghouse’s 650 MW PWR (Pressurized Water Reactor) plant, in operation since March 1982, Angra 2, a Siemmens-KWU’s 1,350 MW PWR plant, in operation since July 2000 and Angra 3, a similar unit of Angra 2, in construction. The Environmental Monitoring Laboratory (EML) (Figure 2) is an installation belonging to ELETRONUCLEAR and is located in Mambucaba Residencial Village, 13 Km far from AAANPS. It was created in 1978 with the purpose to monitore the environment around the Station to verify if there’s a potential impact caused by the operation of the two units. The EML is responsible for the execution of several environmental programs, between the cities of Angra dos Reis and Paraty. One of these programs is the Operational Radiological Environmental Monitoring Program [1], that establishes which the matrices are, the points Figure 1: View of AAANPS Figure 2: View of EML in Mambucaba INAC 2009, Rio de Janeiro, RJ, Brazil. and the frequencies of the collection and the analysis to be done in these matrices, of marine (sea water, beach sand, sediment, algae and fish), terrestrial (milk, grass, banana, soil, surface water, sediment and water river and underground water) and aerial (air and rain water) origin. This paper presents an evaluation of the monitoring on marine environment, in Saco Piraquara de Fora, where the discharge of the units is located, in the period from 2000 to 2008, after the beginning of Angra 2’s operation. The results of radiometric analysis of marine samples, collected in the operational time of the two units, are compared with those from Angra 1 pre-operational time (1978 – 1982) and they show that, during the evaluated time, there was no impact to the environment caused by the Angra 1 & 2 operation. Every year, reports are emitted to the CNEN, IBAMA and INEA having an evaluation of each monitoration done [2]. 2. METHODOLOGY Some samples of marine origin were chosen to be the indicators of the critical ways of radionuclides transference to people and by the experience acquired during the pre- operational program. The sample collection points were determined from geographical, hidrological, oceanographical data, population habits and uses of the ground and are divided in impact area, in which is expected some effects due to the discharge of the liquid effluents of the AAANPS, and control area, in which such effects is not expected [3, 4]. The sample collections, the preparation methods and the analysis of the samples are according to the specific procedures [5, 6]. 2.1 Sea Water Five liters of sea water samples are collected, once a month, in two points of Piraquara bay and in one point in Brandão Island, using an oceanographical bottle (Van Dorn’s Bottle) (Figure 3), at 1 m deep. In lab, the samples are filtered and 4 L aliquots are acidulated with concentrated nitric acid. The samples are, then, put into appropriated plastic flasks (4 L Marinelli), weighted and analysed by gamma spectrometry. A 50 mL fraction of samples not acidulated, is separated to perform compound samples to be analysed for the determination of tritium ( 3H) by liquid scintillation counting. INAC 2009, Rio de Janeiro, RJ, Brazil. Figure 3: Van Dorn’s Bottle 2.2 Beach Sand The beach sand samples are collected, semestrally, at two points in Piraquara beach, 1 m above the line water, in several aliquots, until 2 Kg of the material is obtained. In lab, the samples are put into appropriated plastic flasks (1 L Marinelli), weighted and analysed by gamma spectrometry. 2.3 Fish The species of fishes, collected and analysed in EML, are watercourse and sedentary fish. The watercourse fishes are from Diapterus Rhombeus family (ex. Carapeba) (Figure 4) and the sedentary fishes are from Serranidae family (ex. Garoupa / Badejo) (Figure 5). The watercourse fishes are collected, twice a year, by trawl-net in Saco de Piraquara de Fora bay while the sedentary fishes are collected, each three months, with a bamboo submarine trap called “covo”. In lab, the fishes are weighted (about 4 Kg), cleaned to remove scales and fish-bones and put in a tray to be calcinated. The calcination of the samples is made for 12 hours in 400 oC. The ashes are passed through several sieves to separate the material that was not calcinated, transferred to appropriated plastic flasks and analysed by gamma spectrometry. INAC 2009, Rio de Janeiro, RJ, Brazil. Figure 4: Watercourse Fish (Carapeba) Figure 5: Sedentary Fish (Garoupa) 2.4 Sediment The marine sediment samples are collected, quarterly, using a stainless steel equipment called “Busca-Fundo” (Figure 6), in three points in Saco de Piraquara de Fora bay, called Point 26, Point 29 and Point 47. In lab, the samples are weighted, put into appropriated plastic flasks (1 L Marinelli) and analysed by gamma spectrometry. INAC 2009, Rio de Janeiro, RJ, Brazil. Figure 6: “Busca-Fundo” 2.5 Algae The algae, collected and analysed in EML, are from Sargassum family (Figure 7), belonging to Phaeophyta (brown algae) division, which are found in the infra-littoral (a submersed region by the sea). The algae are collected, quarterly, in manual way by a plunge, and the biologist takes care to bring only the foliole and the thallus. The algae are collected at the same points as sediments. In lab, the thallus and the folioles are washed with sea water, collected in the same place of the algae, cleaned with a brush to eliminate residues of sand and weighted (about 2 Kg). The samples are calcinated for 12 hours at 400 oC and the ashes are passed through sieves to remove material which was not calcinated, put into appropriated plastic flasks and analysed by gamma spectrometry. Since 2001, due to natural conditions, there’s no samples of Sargassum at the three points in Saco de Piraquara de Fora bay. So this kind of monitoring was interrupted. INAC 2009, Rio de Janeiro, RJ, Brazil. Figure 7: Sargassum 3. RESULTS The average results of the analysis of marine samples (sea water, beach sand, fish and marine sediment), from 1978 to 1982 (pre-operational time of Angra 1), from 1996 to 2000 (pre- operational time of Angra 2) and from 2001 to 2008, are shown below in tables 1 to 4. As it was mentioned before, there’s no results for algae samples. The table 5 shows the MDA values of the counting equipments of EML. Table 1: Sea Water YEARS 40 K (Bq/L) 3H (Bq/L) Pre-operational Angra 1 (1978 – 1982) 11,35 < MDA Pre-operational 12,25 < MDA Angra 2 (1996 – 2000) 2001 13,39 < MDA 2002 11,46 < MDA 2003 10,96 < MDA 2004 11,37 < MDA 2005 12,76 < MDA 2006 11,63 < MDA 2007 10,82 < MDA 2008 11,24 < MDA Note : MDA – Minimum Detectable Activity INAC 2009, Rio de Janeiro, RJ, Brazil. Table 2: Beach Sand Table 3: Fish WATERCOURSE SEDENTARY YEARS 40 K (Bq/Kg) YEARS FISH FISH 40 K (Bq/Kg) 40 K (Bq/Kg) Pre-operational Pre-operational 777,92 ------ 61,89 Angra 1 (1978 – 1982) Angra 1 (1978 – 1982) Pre-operational Pre-operational 635,23 118,80 80,17 Angra 2 (1996 – 2000) Angra 2 (1996 – 2000) 2001 529,32 2001 56,97 53,32 2002 826,31 2002 45,63 75,00 2003 505,71 2003 96,34 63,90 2004 595,69 2004 68,58 57,85 2005 589,35 2005 68,02 85,85 2006 449,82 2006 75,09 88,49 2007 595,85 2007 71,82 65,74 2008 595,85 Table 4: Marine2008 Sediment 52,73 68,97 Table 4: Marine Sediment YEARS 40 K (Bq/Kg) 54 Mn (Bq/Kg) 60 Co (Bq/Kg) 137 Cs (Bq/Kg) Pre-operational Angra 1 (1978 – 1982) 445,48 < MDA < MDA 1,15 Pre-operational 529,76 0,83 3,52 1,21 Angra 2 (1996 – 2000) 2001 487,22 < MDA 1,35 < MDA 2002 444,79 0,24 1,55 < MDA 2003 386,11 0,26 0,49 0,23 2004 467,97 0,29 0,46 < MDA 2005 433,21 0,35 1,14 0,16 2006 471,10 < MDA 1,20 < MDA 2007 365,23 0,15 1,14 < MDA 2008 329,50 0,21 0,46 < MDA Note : MDA – Minimum Detectable Activity Table 5: MDA Values for EML VIA SEA BEACH FISH SEDIMENT ALGAE WATER SAND RADIO- (Bq/Kg) (Bq/Kg) (Bq/Kg) (Bq/L) (Bq/Kg) NUCLÍDES 3H 10,00 - - - - 7Be - 0,47 - - 0,50 40 K 1,50 1,15 2,90 2,50 1,20 54 Mn 0,30 0,07 1,10 0,37 0,20 58 Co 0,32 0,07 1,10 0,48 0,41 60 Co 0,30 0,09 1,20 0,45 0,41 131 I 0,90 - - - 0,22 134 Cs 0,25 0,06 0,90 0,36 0,12 137 Cs 0,25 0,05 1,00 0,43 0,16 The pictures below, present the activities of 40 K in the samples of sea water (Figure 8), beach sand (Figure 9), fish (Figure 10) and marine sediment (Figure 11a) and 54 Mn, 60 Co and 137 Cs in the samples of sediment (Figure 11b) from pre-operational time of Angra 1 until 2008.