Journal of Environmental Radioactivity 147 (2015) 8e13
Contents lists available at ScienceDirect
Journal of Environmental Radioactivity journal homepage: www.elsevier.com/locate/jenvrad
Pre-assessment of dose rates of 134Cs, 137Cs, and 60Co for marine biota from discharge of Haiyang Nuclear Power Plant, China Jingjing Li, Senlin Liu*, Yongxing Zhang, Ling Chen, Yuan Yan, Weiya Cheng, Hailin Lou, Yongbao Zhang China Institute of Atomic Energy, Beijing, 102413, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 February 2014 Received in revised form 30 April 2015 Accepted 3 May 2015 Available online
Haiyang Nuclear Power Plant to be built in China was selected as a case for the dose pre-assessment for marine biota in this study. The concentrations of Cs and Co in organisms (turbot, yellow croaker, swimming crab, abalone, sea cucumber, and sea lettuce), seawater, and bottom sediment sampled on-site were measured by neutron activation analysis, and the site-specific transfer parameters (concentration ratios and distribution coefficients) of Cs and Co were calculated. 134Cs, 137Cs, and 60Co activity concentrations in the organisms and the sediment at the site were calculated with the site-specific transfer parameters and the anticipated activity concentrations in the liquid effluent of the nuclear power plant. The ERICA tool was used to estimate the dose rates of 134Cs, 137Cs, and 60Co to the selected organisms based on the biological models developed. The total dose rates of 134Cs, 137Cs, and 60Co to the six organisms were all 3.70Eþ4 Bq a1 in the expected liquid effluent (Westinghouse Electric Co (WEC), 2008). Under normal circumstances, the elements corresponding to these radionuclides that can be analyzed by NAA are Cs, Co, Ba, Ce, Cr, Fe, Ni, Rb, Sr, Zn, and Zr (Qian et al., 1984). The Sea Water Quality Standard of China proposes standards for the activity concentrations of 5 radionuclides in sea water, among which 134Cs, 137Cs, and 60Co are in the expected discharge inventory. Only the concentrations of these 3 radionuclides in the liquid discharge are provided in the public version of the EIA report on Haiyang NPP (Shanghai Nuclear Engineering Research and Design Institute (SNERDI), 2013), so they were chosen for the assessment in this work. The concentrations of other radionuclides
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
in the expected discharge inventory were unknown; therefore, the current assessment for Haiyang NPP was incomplete. 2. Materials and methods 2.1. Study site Haiyang NPP in Shandong Province, China, is located on a headland surrounded on three sides by the Yellow Sea (Fig. 1). The radioactive liquid effluent will be discharged into the sea. A variety of economic species of fish, crab, shrimp, shellfish, and algae inhabit and breed in the sea around the site. A biological survey of the sea around the site is presented in the EIA report on Haiyang NPP (SNERDI, 2013), and the report lists the organisms in the area, so we selected a set of organisms for the pre-assessment. The main criteria for selection were that they were dominant in the inventory of the biological survey, were from different categories, were familiar to the public, and could be collected at the site during the sampling period. The selected organisms were turbot (Scophthalmus maximus), yellow croaker (Pseudosciaena polyactis), swimming crab (Portunus strituberculatus), abalone (Haliotis discus hannai), sea cucumber (Oplopanax elatus nakai), and sea lettuce (Ulva lactuca). 2.2. Sampling and preparation Sampling was conducted from January 17 to 18, 2013. The location of the sampling point is shown in Fig. 1. 2.2.1. Seawater samples Water samples were collected at a depth of 0.5 m from a randomly-selected site (Fig. 1) ~8 km from the outlet of Haiyang NPP. Two parallel samples were collected in a 5 L plastic bucket washed with seawater. The supernatant was filtered through a 0.45 mm Millipore filter. The amount of each filtered sample was 500 ml. Since there is a certain amount of bioactivity in most
9
natural seawater samples, 3 ml HNO3 was added to the samples to keep the pH at 1.5. The two samples were mixed and homogenized, placed in a labeled airtight container made of poly tetra fluoro ethylene (PTFE), which does not absorb most elements, and then transported to the laboratory for processing. Because the concentrations of elements to be analyzed in seawater were relatively low, the samples were concentrated first. The freeze-drying method was used to pre-process the seawater sample using an LGJ-B1 freeze dryer.
2.2.2. Bottom sediment samples Bottom sediment was collected with a grab sampler at the same location as the seawater sampling at a depth of 12 m. Two parallel samples were collected. The supernatant was removed, and 0.1 kg of each sample were mixed and homogenized, transferred to a labeled jar, and transported to the laboratory for processing. The sediment sample was naturally dried to a constant weight and ground into powder through a 100-mesh sieve. The powder was baked for 2 h at 95 ± 5 C. 2.2.3. Biological samples A sufficient number (no less than 100 g) of each species was collected near the seawater-sampling site. The trapped animals were all well-developed and mature individuals, and the sea lettuce collected from the bottom was living and fresh. To develop the dosimetric model for calculating the dose rate to each species, the geometric dimensions and the wet mass of the organisms were measured and recorded (Table 1). The fresh biological samples were separately enclosed in labeled plastic bags and placed on ice for shipment to the laboratory, where they were processed by refrigeration drying: samples were placed in a cold closet to allow natural evaporation, leaving a residue. The sea lettuce was allowed to dry naturally.
Fig. 1. Location of Haiyang NPP and the sampling point. The map is from http://map.baidu.com/.
10
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
Table 1 Sampling records of organisms. Sample
Dimensions Height (m)
Turbot Yellow croaker 1 Yellow croaker 2 Swimming crab 1 Swimming crab 2 Abalone 1 Abalone 2 Sea cucumber 1 Sea cucumber 2 Sea lettucea
3.0E2 5.0E2 4.5E2 4.0E2 3.0E2 2.3E2 2.3E2 2.5E2 3.0E2 1.8E1
Table 3 Comparison of measured and standard concentrations (106 kg kg1) of Cs and Co in standard reference materials.
Wet mass (kg) Width (m) 2.6E1 1.5E2 2.0E2 1.6E1 1.4E1 4.8E2 5.0E2 4.0E2 6.0E2 5.0E2
Element
Length (m) 3.3E1 1.9E1 2.0E1 8.0E2 7.0E2 7.5E2 7.7E2 1.4E1 1.3 E1 5.0E2
6.7E1 7.0E2 7.0E2 2.1E1 1.4E1 4.8E2 5.5E2 1.1E1 1.4E1 2.3E1
Cs Co
GBW07105
GBW07403
Measured value
Standard value
Measured value
Standard value
e 49.2 ± 0.3
e 46.5 ± 5.2
2.9 ± 0.03 5.2 ± 0.05
3.2 ± 0.5 5.5 ± 1.0
3. Calculations 3.1. CRs and Kds
a A tuft made up of three single plants was collected. The dimensions and mass are the average values for a single plant.
Each species (including multiple individuals of each species) was homogenized in a blender to produce a whole-body composite sample, and ground into powder through a 100-mesh sieve. The power was baked under the same conditions as the sediment sample. During storage and processing, all samples were protected from contamination: rubber gloves were worn by staff, liquid samples were stored in PTFE containers, and solid samples were placed in plastic containers.
In aquatic systems, the concentration ratio CR (Bq kg1 WM per Bq L1) for radionuclide i in a specific organism is defined by the following equation (Hosseini et al., 2008):
CRi ¼
(1)
where Cbiota,i is the activity concentration of radionuclide i in the whole body of the organism (Bq kg1 WM), and Cwater,i is the activity concentration of radionuclide i in the water (Bq L1). The sediment distribution coefficient Kd (L kg1) for radionuclide i is defined by the equation below (International Atomic Energy Agency (IAEA), 2001):
Kd;i ¼ 2.3. Neutron activation analysis To verify the validity of the NAA system and control the analysis quality, two national standard reference materials were used: GBW07105, the standard material for component analysis of rock, and GBW07403, the standard material for component analysis of soil. Aliquots of 150e200 mg from each sample were weighted on a precision electronic balance, and then individually packed in aluminum foil. The packed samples and standard reference materials were placed in a dedicated aluminum pot, and then put into the active zone of the miniature neutron source reactor at the China Institute of Atomic Energy. The neutron flux rate was 5.00E11 cm2 s1, and the irradiation time was 30 h. After irradiation, the samples were analyzed directly for gamma-emitting radionuclides with a JC 4018 high-purity germanium gamma detector. Cs and Co concentrations in the samples and uncertainties are shown in Table 2. The concentrations are reported as kg L1 (water) and kg kg1 wet mass (WM) (sediment and organisms). The measured Cs and Co concentrations in standard materials showed good agreement (Table 3).
Cbiota;i Cwater;i
Csed;i Cwater;i
(2)
where Csed,i is the activity concentration (Bq kg1) of radionuclide i in bottom sediments (other terms as previously defined). CRs and Kds are generally given in the form of an element, and the data source is from the stable or radioactive isotope. In this work, CRs and Kds for Cs and Co were calculated with the concentrations of stable isotopes (Table 2), while the activity concentrations in Equations (1) and (2) were replaced by weight concentrations. The results are listed in Table 4. 3.2. Input data for organisms The ERICA tool (Brown et al., 2008) is a program implementing the tiered approach to assess biota at radiological risk, and provides users the option to create their own organisms in tiers 2 and 3. Tier 2 in ERICA 1.2 was used to calculate the dose rates to the organisms selected in this work. The organism is simplified to a sphere or ellipsoid in the tool (Zinger et al., 2007), and the data to create new organisms are shown in Table 5. Because the actual shapes of the organisms were irregular, the geometric dimensions were adjusted to match the mass.
Table 2 Cs and Co concentrations in samples and uncertainties. Sample
Seawater Sediment Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Cs
Co
Concentration (kg L1 or kg kg1 WM)
Uncertainty (%)
Concentration (kg L1 or kg kg1 WM)
Uncertainty (%)
4.5E10 5.1E6 4.2E8 1.3E8 3.5E8 6.5E9 1.6E7 1.6E7
9.2 1.1 3.6 4.9 1.7 4.4 3.8 1.5
1.3E9 9.9E6 4.5E7 2.2E7 2.7E7 4.5E7 2.0E8 4.0E7
3.6 0.8 0.9 0.8 0.6 0.5 1.6 0.9
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
11
Table 4 Calculated CRs for selected organisms and Kds of Cs and Co. Parameter CR (Bq kg1 WM per Bq L1)
Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Kd (L kg1 WM)
Cs
Co
9.4Eþ1 2.8Eþ1 7.9Eþ1 1.5Eþ1 1.1Eþ1 3.6Eþ2 1.1Eþ4
3.6Eþ2 1.7Eþ2 2.1Eþ2 3.6Eþ2 1.6Eþ1 3.1Eþ2 7.8Eþ3
Table 5 Data used in the ERICA tool to create new organisms. Name
Wildlife group
Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Fish Fish Crustacean Molluscs Aquatic invertebrate Aquatic plant
Occupancy factors Water
Sediment-surface
0.1 0.5 0 0 0 0
0.9 0.5 1 1 1 1
3.3. Activity concentrations In the Haiyang NPP project, the radioactive liquid effluent and cooling water will be discharged from a gross outlet, and the annual average activity concentrations of 134Cs, 137Cs, and 60Co in the effluent for a single unit of the NPP in normal working conditions (SNERDI, 2013) are shown in Table 6. In this assessment, the anticipated 134Cs, 137Cs, and 60Co concentrations in the effluent were regarded as the concentrations in the seawater. The activity concentrations of the radionuclides in the organisms and the sediment were calculated by multiplying the activity concentrations in the water by site-specific CRs and Kds (Brown et al., 2008). The 134Cs, 137Cs, and 60Co concentrations in the media and the organisms in the assessment are shown in Table 6.
Wet mass (kg)
6.9E1 8.0E2 2.1E1 5.0E2 1.2E1 2.6E1
Dimensions Height (m)
Width (m)
Length (m)
2.0E2 8.0E2 4.0E2 2.4E2 3.0E2 2.0E1
2.2E1 2.0E2 1.4E1 5.0E2 6.0E2 5.0E2
3.0E1 1.4E1 7.0E2 8.0E2 1.3E1 5.0E2
Department of Energy (USDOE) (2002), in ERICA the screening dose rate for non-human biota is 10 mGy h1 (Brown et al., 2008), and International Commission on Radiological Protection (ICRP) provides the derived consideration reference levels for the Reference Animals and Plants (ICRP, 2008). In China, there is no legal provision to limit the dose rates to non-human biota, and 400 mGy h1 is mostly used as the dose rate screening level for aquatic biota in the EIA for NPPs (Suzhou Nuclear Power Research Institute Co Ltd (SNPRI), 2013; SNPRI, 2014). In this pre-assessment using site-specific CRs and Kds, the total dose rates of 134Cs, 137Cs, and 60Co to turbot, yellow croaker, swimming crab, abalone, sea cucumber, and sea lettuce were all
Contents lists available at ScienceDirect
Journal of Environmental Radioactivity journal homepage: www.elsevier.com/locate/jenvrad
Pre-assessment of dose rates of 134Cs, 137Cs, and 60Co for marine biota from discharge of Haiyang Nuclear Power Plant, China Jingjing Li, Senlin Liu*, Yongxing Zhang, Ling Chen, Yuan Yan, Weiya Cheng, Hailin Lou, Yongbao Zhang China Institute of Atomic Energy, Beijing, 102413, China
a r t i c l e i n f o
a b s t r a c t
Article history: Received 27 February 2014 Received in revised form 30 April 2015 Accepted 3 May 2015 Available online
Haiyang Nuclear Power Plant to be built in China was selected as a case for the dose pre-assessment for marine biota in this study. The concentrations of Cs and Co in organisms (turbot, yellow croaker, swimming crab, abalone, sea cucumber, and sea lettuce), seawater, and bottom sediment sampled on-site were measured by neutron activation analysis, and the site-specific transfer parameters (concentration ratios and distribution coefficients) of Cs and Co were calculated. 134Cs, 137Cs, and 60Co activity concentrations in the organisms and the sediment at the site were calculated with the site-specific transfer parameters and the anticipated activity concentrations in the liquid effluent of the nuclear power plant. The ERICA tool was used to estimate the dose rates of 134Cs, 137Cs, and 60Co to the selected organisms based on the biological models developed. The total dose rates of 134Cs, 137Cs, and 60Co to the six organisms were all 3.70Eþ4 Bq a1 in the expected liquid effluent (Westinghouse Electric Co (WEC), 2008). Under normal circumstances, the elements corresponding to these radionuclides that can be analyzed by NAA are Cs, Co, Ba, Ce, Cr, Fe, Ni, Rb, Sr, Zn, and Zr (Qian et al., 1984). The Sea Water Quality Standard of China proposes standards for the activity concentrations of 5 radionuclides in sea water, among which 134Cs, 137Cs, and 60Co are in the expected discharge inventory. Only the concentrations of these 3 radionuclides in the liquid discharge are provided in the public version of the EIA report on Haiyang NPP (Shanghai Nuclear Engineering Research and Design Institute (SNERDI), 2013), so they were chosen for the assessment in this work. The concentrations of other radionuclides
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
in the expected discharge inventory were unknown; therefore, the current assessment for Haiyang NPP was incomplete. 2. Materials and methods 2.1. Study site Haiyang NPP in Shandong Province, China, is located on a headland surrounded on three sides by the Yellow Sea (Fig. 1). The radioactive liquid effluent will be discharged into the sea. A variety of economic species of fish, crab, shrimp, shellfish, and algae inhabit and breed in the sea around the site. A biological survey of the sea around the site is presented in the EIA report on Haiyang NPP (SNERDI, 2013), and the report lists the organisms in the area, so we selected a set of organisms for the pre-assessment. The main criteria for selection were that they were dominant in the inventory of the biological survey, were from different categories, were familiar to the public, and could be collected at the site during the sampling period. The selected organisms were turbot (Scophthalmus maximus), yellow croaker (Pseudosciaena polyactis), swimming crab (Portunus strituberculatus), abalone (Haliotis discus hannai), sea cucumber (Oplopanax elatus nakai), and sea lettuce (Ulva lactuca). 2.2. Sampling and preparation Sampling was conducted from January 17 to 18, 2013. The location of the sampling point is shown in Fig. 1. 2.2.1. Seawater samples Water samples were collected at a depth of 0.5 m from a randomly-selected site (Fig. 1) ~8 km from the outlet of Haiyang NPP. Two parallel samples were collected in a 5 L plastic bucket washed with seawater. The supernatant was filtered through a 0.45 mm Millipore filter. The amount of each filtered sample was 500 ml. Since there is a certain amount of bioactivity in most
9
natural seawater samples, 3 ml HNO3 was added to the samples to keep the pH at 1.5. The two samples were mixed and homogenized, placed in a labeled airtight container made of poly tetra fluoro ethylene (PTFE), which does not absorb most elements, and then transported to the laboratory for processing. Because the concentrations of elements to be analyzed in seawater were relatively low, the samples were concentrated first. The freeze-drying method was used to pre-process the seawater sample using an LGJ-B1 freeze dryer.
2.2.2. Bottom sediment samples Bottom sediment was collected with a grab sampler at the same location as the seawater sampling at a depth of 12 m. Two parallel samples were collected. The supernatant was removed, and 0.1 kg of each sample were mixed and homogenized, transferred to a labeled jar, and transported to the laboratory for processing. The sediment sample was naturally dried to a constant weight and ground into powder through a 100-mesh sieve. The powder was baked for 2 h at 95 ± 5 C. 2.2.3. Biological samples A sufficient number (no less than 100 g) of each species was collected near the seawater-sampling site. The trapped animals were all well-developed and mature individuals, and the sea lettuce collected from the bottom was living and fresh. To develop the dosimetric model for calculating the dose rate to each species, the geometric dimensions and the wet mass of the organisms were measured and recorded (Table 1). The fresh biological samples were separately enclosed in labeled plastic bags and placed on ice for shipment to the laboratory, where they were processed by refrigeration drying: samples were placed in a cold closet to allow natural evaporation, leaving a residue. The sea lettuce was allowed to dry naturally.
Fig. 1. Location of Haiyang NPP and the sampling point. The map is from http://map.baidu.com/.
10
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
Table 1 Sampling records of organisms. Sample
Dimensions Height (m)
Turbot Yellow croaker 1 Yellow croaker 2 Swimming crab 1 Swimming crab 2 Abalone 1 Abalone 2 Sea cucumber 1 Sea cucumber 2 Sea lettucea
3.0E2 5.0E2 4.5E2 4.0E2 3.0E2 2.3E2 2.3E2 2.5E2 3.0E2 1.8E1
Table 3 Comparison of measured and standard concentrations (106 kg kg1) of Cs and Co in standard reference materials.
Wet mass (kg) Width (m) 2.6E1 1.5E2 2.0E2 1.6E1 1.4E1 4.8E2 5.0E2 4.0E2 6.0E2 5.0E2
Element
Length (m) 3.3E1 1.9E1 2.0E1 8.0E2 7.0E2 7.5E2 7.7E2 1.4E1 1.3 E1 5.0E2
6.7E1 7.0E2 7.0E2 2.1E1 1.4E1 4.8E2 5.5E2 1.1E1 1.4E1 2.3E1
Cs Co
GBW07105
GBW07403
Measured value
Standard value
Measured value
Standard value
e 49.2 ± 0.3
e 46.5 ± 5.2
2.9 ± 0.03 5.2 ± 0.05
3.2 ± 0.5 5.5 ± 1.0
3. Calculations 3.1. CRs and Kds
a A tuft made up of three single plants was collected. The dimensions and mass are the average values for a single plant.
Each species (including multiple individuals of each species) was homogenized in a blender to produce a whole-body composite sample, and ground into powder through a 100-mesh sieve. The power was baked under the same conditions as the sediment sample. During storage and processing, all samples were protected from contamination: rubber gloves were worn by staff, liquid samples were stored in PTFE containers, and solid samples were placed in plastic containers.
In aquatic systems, the concentration ratio CR (Bq kg1 WM per Bq L1) for radionuclide i in a specific organism is defined by the following equation (Hosseini et al., 2008):
CRi ¼
(1)
where Cbiota,i is the activity concentration of radionuclide i in the whole body of the organism (Bq kg1 WM), and Cwater,i is the activity concentration of radionuclide i in the water (Bq L1). The sediment distribution coefficient Kd (L kg1) for radionuclide i is defined by the equation below (International Atomic Energy Agency (IAEA), 2001):
Kd;i ¼ 2.3. Neutron activation analysis To verify the validity of the NAA system and control the analysis quality, two national standard reference materials were used: GBW07105, the standard material for component analysis of rock, and GBW07403, the standard material for component analysis of soil. Aliquots of 150e200 mg from each sample were weighted on a precision electronic balance, and then individually packed in aluminum foil. The packed samples and standard reference materials were placed in a dedicated aluminum pot, and then put into the active zone of the miniature neutron source reactor at the China Institute of Atomic Energy. The neutron flux rate was 5.00E11 cm2 s1, and the irradiation time was 30 h. After irradiation, the samples were analyzed directly for gamma-emitting radionuclides with a JC 4018 high-purity germanium gamma detector. Cs and Co concentrations in the samples and uncertainties are shown in Table 2. The concentrations are reported as kg L1 (water) and kg kg1 wet mass (WM) (sediment and organisms). The measured Cs and Co concentrations in standard materials showed good agreement (Table 3).
Cbiota;i Cwater;i
Csed;i Cwater;i
(2)
where Csed,i is the activity concentration (Bq kg1) of radionuclide i in bottom sediments (other terms as previously defined). CRs and Kds are generally given in the form of an element, and the data source is from the stable or radioactive isotope. In this work, CRs and Kds for Cs and Co were calculated with the concentrations of stable isotopes (Table 2), while the activity concentrations in Equations (1) and (2) were replaced by weight concentrations. The results are listed in Table 4. 3.2. Input data for organisms The ERICA tool (Brown et al., 2008) is a program implementing the tiered approach to assess biota at radiological risk, and provides users the option to create their own organisms in tiers 2 and 3. Tier 2 in ERICA 1.2 was used to calculate the dose rates to the organisms selected in this work. The organism is simplified to a sphere or ellipsoid in the tool (Zinger et al., 2007), and the data to create new organisms are shown in Table 5. Because the actual shapes of the organisms were irregular, the geometric dimensions were adjusted to match the mass.
Table 2 Cs and Co concentrations in samples and uncertainties. Sample
Seawater Sediment Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Cs
Co
Concentration (kg L1 or kg kg1 WM)
Uncertainty (%)
Concentration (kg L1 or kg kg1 WM)
Uncertainty (%)
4.5E10 5.1E6 4.2E8 1.3E8 3.5E8 6.5E9 1.6E7 1.6E7
9.2 1.1 3.6 4.9 1.7 4.4 3.8 1.5
1.3E9 9.9E6 4.5E7 2.2E7 2.7E7 4.5E7 2.0E8 4.0E7
3.6 0.8 0.9 0.8 0.6 0.5 1.6 0.9
J. Li et al. / Journal of Environmental Radioactivity 147 (2015) 8e13
11
Table 4 Calculated CRs for selected organisms and Kds of Cs and Co. Parameter CR (Bq kg1 WM per Bq L1)
Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Kd (L kg1 WM)
Cs
Co
9.4Eþ1 2.8Eþ1 7.9Eþ1 1.5Eþ1 1.1Eþ1 3.6Eþ2 1.1Eþ4
3.6Eþ2 1.7Eþ2 2.1Eþ2 3.6Eþ2 1.6Eþ1 3.1Eþ2 7.8Eþ3
Table 5 Data used in the ERICA tool to create new organisms. Name
Wildlife group
Turbot Yellow croaker Swimming crab Abalone Sea cucumber Sea lettuce
Fish Fish Crustacean Molluscs Aquatic invertebrate Aquatic plant
Occupancy factors Water
Sediment-surface
0.1 0.5 0 0 0 0
0.9 0.5 1 1 1 1
3.3. Activity concentrations In the Haiyang NPP project, the radioactive liquid effluent and cooling water will be discharged from a gross outlet, and the annual average activity concentrations of 134Cs, 137Cs, and 60Co in the effluent for a single unit of the NPP in normal working conditions (SNERDI, 2013) are shown in Table 6. In this assessment, the anticipated 134Cs, 137Cs, and 60Co concentrations in the effluent were regarded as the concentrations in the seawater. The activity concentrations of the radionuclides in the organisms and the sediment were calculated by multiplying the activity concentrations in the water by site-specific CRs and Kds (Brown et al., 2008). The 134Cs, 137Cs, and 60Co concentrations in the media and the organisms in the assessment are shown in Table 6.
Wet mass (kg)
6.9E1 8.0E2 2.1E1 5.0E2 1.2E1 2.6E1
Dimensions Height (m)
Width (m)
Length (m)
2.0E2 8.0E2 4.0E2 2.4E2 3.0E2 2.0E1
2.2E1 2.0E2 1.4E1 5.0E2 6.0E2 5.0E2
3.0E1 1.4E1 7.0E2 8.0E2 1.3E1 5.0E2
Department of Energy (USDOE) (2002), in ERICA the screening dose rate for non-human biota is 10 mGy h1 (Brown et al., 2008), and International Commission on Radiological Protection (ICRP) provides the derived consideration reference levels for the Reference Animals and Plants (ICRP, 2008). In China, there is no legal provision to limit the dose rates to non-human biota, and 400 mGy h1 is mostly used as the dose rate screening level for aquatic biota in the EIA for NPPs (Suzhou Nuclear Power Research Institute Co Ltd (SNPRI), 2013; SNPRI, 2014). In this pre-assessment using site-specific CRs and Kds, the total dose rates of 134Cs, 137Cs, and 60Co to turbot, yellow croaker, swimming crab, abalone, sea cucumber, and sea lettuce were all
