A · Appendix A: Radiological Assessment of Dredging Application for Hinkley Point C Power Station,...

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Cefas BEEMS Technical Report TR444, HPC intake and outfall location pre- dredge sediment sample analysis results (Marine Licence 12/45/ML)

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Cefas BEEMS Technical Report TR444, HPC intake and outfall location pre-dredge sediment sample analysis results (Marine Licence 12/45/ML)

Dean Foden and Katie Musgrave

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Version and Quality Control

Version Author Date

Draft 0.01 Dean Foden & Katie Musgrave 19/09/2017

Technical QA 0.02 Ralph Brayne 20/09/2017

Executive QA & Final Draft 0.03 Brian Robinson 21/09/2017

Submission to NNB GenCo as

Rev 1

1.00 21/09/2017

Update in response to NNB

GenCo comments

1.01 Dean Foden 08/11/2017



Rev 2

2.00 10/11/2017

Update in response to NNB

GenCo review

2.01 Dean Foden 01/12/2017



Rev 3

3.00 08/12/2017

Minor update in response to

NRW comments

3.01 Dean Foden 01/02/2018


Rev 4

4.00 01/02/2018

Minor update in response to

NNB GenCo comments

4.01 Dean Foden 08/02/2018


Rev 5

5.00

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Table of contents

Executive summary ....................................................................................................................................... 11

1 Introduction .............................................................................................................................................. 12

2 Description of the sediment sampling .................................................................................................. 12

3 Description of the sediment sample analysis ...................................................................................... 15

4 Results ...................................................................................................................................................... 18

5 Discussion ............................................................................................................................................... 22

5.1 Chemical contaminant assessment ..................................................................................................... 22

5.2 Radiological assessment ..................................................................................................................... 24

6 Conclusions ............................................................................................................................................. 26

7 References ............................................................................................................................................... 27

Appendix A: Radiological Assessment of Dredging Application for Hinkley Point C Power Station,

Somerset (2017) ............................................................................................................................................. 28

Appendix B: Radiological Analysis results from vibrocore samples acquired in 2009 by Fugro

Alluvial Offshore Ltd using a 6m vibrocorer and analysed by Cefas. ..................................................... 38

Appendix C: Radiological Analysis results from surface sediment samples acquired in 2013 and

analysed by Cefas. ........................................................................................................................................ 39

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List of Tables and Figures

Tables

Table 1 The coordinates of the proposed sediment sampling locations. .................................... 13

Table 2 Analytical method detection limits for metals, organotins and PAHs and limits of

quantification for PCBs. .............................................................................................. 16

Table 3 Results of radionuclide analyses. Values are specific activity in Bq.kg-1 dry weight. ..... 18

Table 4 Results of metals analyses. Values are in mg.kg-1. ........................................................ 18

Table 5 Results of organotins analyses. Values are in mg.kg-1. ................................................. 19

Table 6 Results of PAH analyses. Values are in µg.kg-1 except for THC which is in mg.kg-1. .... 20

Table 7 Results of PCBs analyses. Values are in µg.kg-1. .......................................................... 21

Table 8 Action Levels determined according to contaminant levels.. ......................................... 23

Table 9 Doses predicted by the IAEA generic radiological assessment (IAEA, 2003; 2004) ..... 24

Table 10 Selected parameters used in the generic assessment and (where available) local

parameters for Cardiff. ............................................................................................... 24

Figures

Figure 1 The locations of the proposed sediment sampling. ....................................................... 14

Figure 2 The sampling vessel – the Titan Endeavour. ................................................................ 15

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Executive summary

Surface sediment samples were acquired at the HPC intake and outfall locations (see Table 1 and Figure 1)

for chemical and radiological analysis to determine the suitability of the material for disposal at sea in

accordance with the approved sampling plan under (NRW) Marine Licence 12/45/ML. Samples were

acquired with a Day grab to a maximum sediment depth of 18cm. Chemical analyses were conducted for

polyaromatic hydrocarbons (PAHs), metals, organotins and polychlorinated biphenyls (PCBs). Radionuclide

analysis was conducted by Gamma counting samples on a high purity Germanium detector, including

detection of man-made radionuclides Cobalt-60, Caesium-137 and Americium-241.and naturally occurring

radionuclides potassium-40, radium-226, thorium-232 and uranium-238.

Contaminant levels measured during chemical analysis were compared with CEFAS Action Levels (MMO,

2015). Cefas Action Levels determine the suitability of dredged material for disposal at sea and two Action

Levels are employed. Each Action Level has an associated suite of contaminants that are routinely tested in

dredged sediment as part of a weight of evidence approach to inform marine disposal licence applications:

Contaminant concentrations that are below those defined for Action Level 1 are not considered to be of

environmental concern and hence are unlikely to influence the disposal options. However, when

contaminants are present above Action Level 2 the dredged sediment is not considered suitable for reuse or

disposal at sea. Between the Action Levels further assessment is required.

The results of the chemical analyses showed that no contaminants were determined to be at or above Action

Level 2 at any sampling station. Slight exceedances of Action Level 1 were detected for PCBs, zinc, nickel,

lead and chromium at all sites. Slight exceedances of Action Level 1 were detected for cadmium and

mercury at sampling station HPCD06 only. Where Action Level 1 was exceeded, the measured

concentrations were significantly below Action Level 2 (by an order of magnitude) with the exception of zinc,

for which the maximum measured concentration was 262.18 mg.kg-1 (at station HPCD11) and the Cefas

Action Level 2 for zinc is 800 mg.kg-1. The results are consistent with previously conducted analyses of

seabed sediment samples from the Severn Estuary where background concentrations typically exceed

Action Level 1 (e.g. chromium concentrations up to 67 mg.kg-1; lead concentrations up to 141 mg.kg-1; nickel

concentrations up to 59 mg.kg-1; zinc concentrations up to 307 mg.kg-1 and PCB concentrations up to 61

μg.kg-1 were measured in sediments collected near the HPC site in 2009 (BEEMS Technical Report

TR186)). There was, therefore, no indication that the sediments were unsuitable for disposal at sea.

A conservative radiological assessment procedure (in line with International Atomic Energy Agency (2004)

guidelines) indicated that:

a. doses received were mostly from naturally-occurring radioactivity;

b. doses were well below recommended limits; and

c. a subsequent more detailed case specific assessment was not necessary.

Under the London Convention, only materials with de minimis levels of radioactivity may be considered for

disposal to sea. Using the conservative generic radiological assessment procedure developed by the IAEA

(IAEA, 2003; 2004), to convert radionuclide concentrations in disposed material into radiation doses due to

disposal, the derived total doses to individual members of the crew and public were 5.8 µSv/year and 1.9

µSv/year respectively. The total collective dose was 0.035 manSv/year. The values for individual members of

the crew and public, and the collective dose, were well within the de minimis criteria of 10 µSv/year

(individual doses) and 1 manSv/year (collective dose), respectively.

The radiological results were consistent with previous analyses of sediment samples acquired in 2009

(BEEMS Technical Report TR186) and 2013 (Leonard et al., 2013). Therefore, there is no radiological

reason that this material should not be disposed of to sea.

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1 Introduction

Cefas was commissioned by NNB Generation Company (HPC) Ltd (NNB GenCo) to collect and analyse

surface sediment samples from the proposed cooling water intake and outfall locations for Hinkley Point C

(HPC) nuclear power station. Construction of the intake and outfall structures requires the locations to be

dredged, and the dredged material to be taken to a designated disposal site. Permission to dispose of this

material in disposal area LU110 (Cardiff Grounds) is granted in Natural Resources Wales (NRW) Marine

Licence 12/45/ML (NRW, 2014). Condition 9.3 of this licence required the submission and approval of a

sediment sampling scheme prior to the disposal of material. BEEMS technical report TR415 (BEEMS, 2016),

outlining the sampling scheme, was produced to satisfy this requirement and was approved by NRW (NRW,

2017). Sediment samples were acquired as per the approved plan in May 2017 and the purpose of this

report is to present the results of the analyses of these samples to demonstrate the suitability for disposal at

sea of the sediments around the HPC intake and outfall locations.

2 Description of the sediment sampling

During 2017, sampling was carried out at the locations marked in Figure 1 and two samples were collected

from each of the intake and outfall areas. The coordinates of the sampling locations are shown in Table 1.

Samples were acquired on the 2nd May 2017.

Sampling consisted of deploying a 0.1 m2 Day grab from a small survey vessel (Figure 2). The maximum

sediment depth sampled by the grab used was 18 cm, and samples were taken from approximately the top

2cm of the sediment surface. The volume of sediment acquired for each sample taken was approximately 3

l. Sediment acquired for chemical analysis was placed in solvent-cleaned glass jars using a stainless-steel

scoop, with approximately 500 g of sediment being retained per sample. Once ashore, the samples were

frozen, placed in insulated boxes and sent by courier to Cefas’ laboratory in Lowestoft for analysis. Sediment

for radiological analysis was placed in clean pots and stored either refrigerated or at room temperature,

avoiding being frozen or exposed to strong direct sunlight.

During previous sediment sampling undertaken off Hinkley Point, surface sediment samples were acquired

in 2013, and surface and sub-surface samples were taken using vibrocoring in 2009 (see section 5.2).

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Table 1 The coordinates of the proposed sediment sampling locations.

Station Zone

Target locations Actual sampling locations Distance of sampling from target (m)

Coordinates (OSGB) WGS84 latitude and longitude Coordinates (OSGB)

WGS84 latitude and longitude

Easting Northing Latitude (°N)

Longitude (°W) Easting Northing

Latitude (°N)

Longitude (°W)

HPCD06 outfall

zone 319130 147604 51.22188 3.15942 319134 147610 51.22193 3.15935 7.2

HPCD07 outfall

zone 319105 147580 51.22167 3.15977 319113 147560 51.22148 3.15963 21.5

HPCD08 outfall

zone 319177 147495 51.22091 3.15872 319176 147487 51.22083 3.15872 8.1

HPCD09 outfall

zone 319205 147520 51.22114 3.15833 319197 147519 51.22112 3.15842 8.1

HPCD10 intake

zone 318475 149030 51.23461 3.16912 318470 149026 51.23457 3.16917 6.4

HPCD11 intake

zone 318440 149000 51.23434 3.16962 318424 148995 51.23428 3.16982 16.8

HPCD12 intake

zone 317985 148877 51.23317 3.17610 317952 148869 51.23308 3.17655 34.0

HPCD13 intake

zone 317994 148822 51.23267 3.17596 317965 148815 51.23260 3.17635 29.8

HPCD14 intake

zone 318145 148670 51.23133 3.17377 318117 148676 51.23137 3.17415 28.6

HPCD15 intake

zone 318180 148705 51.23165 3.17327 318171 148698 51.23158 3.17338 11.4

HPCD16 intake

zone 318620 148820 51.23274 3.16700 318608 148823 51.23277 3.16715 12.4

HPCD17 intake

zone 318610 148880 51.23328 3.16716 318603 148885 51.23332 3.16723 8.6 A - ACCEPTE

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Figure 1 The locations of the proposed sediment sampling. Actual sampling locations were all within a maximum of 34 m of the target locations and the mean

difference between target and actual sampling location was 16 m. The 4 HPC intakes are shown in Map 2, the 2 outlets are in Map 3.

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Figure 2 The sampling vessel – the Titan Endeavour.

3 Description of the sediment sample analysis

The acquired samples were analysed for radionuclides and chemical contaminants. Chemical analyses for

polyaromatic hydrocarbons (PAHs), metals, organotins and polychlorinated biphenyls (PCBs) were carried

out, as well as radionuclide analysis at the Cefas Lowestoft Laboratory. Analyses were carried out for those

contaminants for which Cefas Action levels are published.

Radionuclides

Radionuclide analysis was conducted by Ɣ counting samples on a high purity Ge detector which detects any

activity within the energy range 60 keV to 2 MeV. This report includes results for all radionuclides present

and no further activity was detected for any other radionuclide. Results of the analyses were assessed using

generic radiological assessment procedure developed by the International Atomic Energy Agency (IAEA,

2004) (see Appendix A: Radiological Assessment of Dredging Application for Hinkley Point C Power Station,

Somerset (2017)). Chemical and radiological analyses were the same as those used for the samples

acquired in 2013 (Leonard et al., 2013).

Metals (partial digestion)

Microwave digestion with nitric acid and analysis by inductively coupled plasma mass spectroscopy (ICP-

MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES).

Organotins

Organotins were extracted from the sediment sample, converted into their hydrides using sodium

borohydride, extracted, and analysed by gas chromatography – flame photometric detection (GC-FPD).

PAHs

Analysis for aromatic hydrocarbons was achieved using gas chromatography-mass spectrometry (GC-MS).

Additionally, a total hydrocarbon (THC) measurement focussing on 2 and 3-ringed hydrocarbons was

performed using UV fluorescence spectrophotometry calibrated with a Forties oil standard.

PCBs

The sediment was dried and sieved to a less than 2mm fraction. The dried sediment was extracted by

soxhlet, the extracts cleaned and analysed by gas chromatography with electron capture detection (GC-

ECD).

The limits of detection and quantification of the analyses to be conducted are shown in Table 2.

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Table 2 Analytical method detection limits for metals, organotins and PAHs and limits of quantification for

PCBs.

Determinant Limit of detection (dry weight basis)

Metals (partial digestion)

Arsenic (As) 0.01 mg/kg

Cadmium (Cd) 0.01 mg/kg

Chromium (Cr) 0.01 mg/kg

Copper (Cu) 0.01 mg/kg

Lead (Pb) 0.01 mg/kg

Mercury (Hg) 0.006 mg/kg

Nickel (Ni) 0.01 mg/kg

Zinc (Zn) 0.20 mg/kg

Organotins

Tribultyl tin (TBT) 2 µg/kg

Dibutyl tin (DBT) 2 µg/kg

Polyaromatic Hydrocarbons (PAHs):

Acenaphthene 0.1 µg/kg

Acenaphthylene 0.1 µg/kg

Anthracene 0.1 µg/kg

Benzo[a]anthracene 0.1 µg/kg

Benzo[a]pyrene 0.1 µg/kg

Benzo[b]fluoranthene 0.1 µg/kg

Benzo[e]pyrene 0.1 µg/kg

Benzo[ghi]perylene 0.1 µg/kg

Benzo[k]fluoranthene 0.1 µg/kg

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C1-Naphthalenes 0.1 µg/kg

C1-Phenanthrenes 0.1 µg/kg



Chrysene 0.1 µg/kg

Fluoranthene 0.1 µg/kg

Fluorene 0.1 µg/kg

Indeno[123-cd]P 0.1 µg/kg

Naphthalene 0.1 µg/kg

Perylene 0.1 µg/kg

Phenanthrene 0.1 µg/kg

Pyrene 0.1 µg/kg

Dibenz(a,h)anthracene 0.1 µg/kg

Total Hydrocarbon Content (THC) 0.1 mg/kg

25 Polychlorinated Biphenyls (PCBs) congeners (as per IUPAC nomenclature):

CB 18, CB 28a, CB 31, CB 44, CB 47, CB 49,

CB 52, CB 66, CB101a, CB 105, CB 110,

CB 118a, CB 128, CB 138a, CB141, CB149,

CB 151, CB 153a, CB 156, CB 158, CB 170,

CB 180a, CB 183, CB 187, CB 194

Limit of quantification

Per congener = 0.2 µg/kg

Sum of ICES7 = 1.4 µg/kg

Sum of 25 congeners = 5.0 µg/kg

Key = a ICES7 congener1

1 The seven ICES (International Council for the Exploration of the Sea) PCBs (CB28, 52, 101, 118,

153, 138, and 180) are routinely monitored and used as indicators of wider PCB contamination due to

their relatively high concentrations in technical mixtures and their wide chlorination range (3-7

chlorine atoms per molecule).

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4 Results

The results of chemical analyses are presented below. The details of the radiological analyses are shown in Appendix A: Radiological Assessment of Dredging Application for Hinkley Point C Power Station, Somerset (2017).

Table 3 Results of radionuclide analyses. Values are specific activity in Bq.kg-1 dry weight.

Analysis Sampling station

HPCD06 HPCD07 HPCD08 HPCD09 HPCD10 HPCD11 HPCD12 HPCD13 HPCD14 HPCD15 HPCD16 HPCD17

60Co < 0.4 < 0.4 < 0.4 < 0.4 < 0.5 < 0.3 < 0.4 < 0.4 < 0.5 < 0.4 < 0.4 < 0.4

137Cs 19.5 19.5 17.9 17.5 14.9 14.7 15.1 15.1 14.8 14.8 12.8 13.7

226Ra (via 214Pb) 23 22.3 21.8 23.2 19.8 21.4 21.7 21.7 21.7 23.1 23.8 22

232Th (via 228Ac) 37.4 37.9 33 32.4 28.9 29.7 28.9 29.1 26.6 28.2 29.5 29.5

238U (via 234Th) 62.2 57.5 66.3 54.3 41.8 48.7 45.8 51.7 48.6 49 46.7 46.8

241Am < 1.46 < 1.57 < 1.42 < 1.57 < 1.68 < 1.12 < 1.38 < 0.59 < 0.62 < 1.41 < 1.52 < 1.36

Note: There are two types of results presented in the table above: (i) positively detected values and (ii) values that were below the Limit of Detection (LoD) or Minimum

Reporting Level (MRL) which are preceded by a ‘less than’ symbol (“<”).

Table 4 Results of metals analyses. Values are in mg.kg-1.



Arsenic (As) 19.98 16.73 15.30 15.54 16.77 19.06 14.13 18.28 16.17 15.92 15.16 14.26

Cadmium (Cd) 0.46 0.36 0.32 0.32 0.32 0.35 0.27 0.35 0.30 0.32 0.30 0.29

Chromium (Cr) 60.51 57.34 53.03 52.65 54.27 68.49 47.88 59.10 51.94 54.06 49.26 45.75

Copper (Cu) 31.63 27.99 25.27 25.71 24.96 32.16 22.67 27.48 24.82 24.89 23.66 22.08

Lead (Pb) 83.73 74.62 68.38 66.90 65.48 76.80 56.69 73.22 65.58 64.40 61.94 59.92

Mercury (Hg) 0.34 0.27 0.21 0.23 0.22 0.26 0.21 0.24 0.21 0.26 0.21 0.18

Nickel (Ni) 38.41 37.31 35.03 35.12 34.25 44.55 31.25 37.97 35.02 35.35 33.63 31.10

Zinc (Zn) 245.42 227.33 210.02 208.04 203.15 262.18 181.65 232.42 204.87 202.60 193.2 179.85 A - ACCEPTE

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Table 5 Results of organotins analyses. Values are in mg.kg-1.



DBT <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002

TBT <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 <0.002

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Table 6 Results of PAH analyses. Values are in µg.kg-1 except for THC which is in mg.kg-1.



THC (Total Hydrocarbon Content)

868 311 394 462 485 483 364 413 469 420 380 413

Acenaphthylene 42.6 16.0 22.1 25.8 24.3 27.1 22.8 22.6 38.8 24.0 25.4 24.0

Acenapthene 92.9 33.7 43.3 51.7 46.2 52.6 42.9 47.3 57.2 49.9 45.6 45.3

Anthracene 223 79.8 103 124 111 130 111 116 234 116 131 104

Benz [a] anthracene 568 202 274 341 290 334 271 270 483 311 306 293

Benzo [a] pyrene 646 245 315 382 340 387 300 327 440 341 347 353

Benzo [b] fluoranthene 879 327 451 506 476 518 402 431 561 465 495 454

Benzo [g,h,i] perylene 601 239 288 344 329 371 278 318 348 305 306 318

Benzo [e] pyrene 666 256 326 391 360 412 321 352 423 359 341 351

Benzo [k] fluoranthene 338 134 183 211 204 218 163 193 259 188 194 192

Methyl naphthalenes 690 256 334 383 405 412 363 376 400 427 470 410

Methyl phenanthrene 972 358 472 531 564 575 527 515 741 580 501 475

Dimethyl naphthalenes 1170 429 570 660 677 715 655 654 695 724 605 545

Trimethyl naphthalenes 1500 558 744 851 972 882 894 926 964 940 834 740

Chrysene 502 209 284 349 306 372 286 321 497 320 289 252

Dibenz [a,h] anthracene 145 54.4 67.0 82.4 74.9 83.4 61.8 71.9 87.2 72.9 72.4 75.0

Fluoranthene 1170 415 553 651 591 675 539 525 1020 621 621 596

Fluorene 220 77 98 112 112 122 97.0 107 142 106 118 113

Indeno [1,2,3-cd] pyrene 770 295 369 441 415 464 344 390 451 391 408 420

Naphthalene 337 125 160 183 191 203 176 183 179 193 175 178

Perylene 280 103 133 153 142 157 121 131 155 134 142 145

Phenanthrene 697 260.0 348 388 392 434 365.0 379 721.0 401 350 343

Pyrene 836 306 406 481 439 504 407 402 733 458 449 445

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Table 7 Results of PCBs analyses. Values are in µg.kg-1.



CB#28 8.17 6.67 5.52 5.66 5.35 5.65 5.79 4.88 5.22 4.93 5.11 3.40

CB#52 3.11 2.59 2.28 2.42 2.24 2.63 2.93 1.95 2.35 1.92 2.45 1.41

CB#101 2.90 2.51 2.06 2.22 2.17 2.29 2.49 1.95 2.19 1.80 2.10 1.26

CB#118 3.39 2.78 2.27 2.51 2.48 2.37 2.20 2.28 2.51 2.26 2.01 1.56

CB#153 4.68 4.25 3.26 3.71 3.55 3.64 3.43 3.31 3.61 3.10 3.01 2.11

CB#138 5.08 4.59 3.72 4.04 3.68 3.69 3.78 3.53 3.99 3.35 3.11 2.41

CB#180 3.93 3.58 2.58 2.94 2.85 2.78 2.63 2.50 3.21 2.64 2.09 1.73

CB#31 5.43 4.37 3.91 3.91 3.64 4.36 4.43 3.23 3.85 3.23 3.65 2.33

CB#105 1.37 1.19 0.956 1.06 0.988 1.03 0.964 0.941 1.06 0.867 0.785 0.642

CB#128 0.936 0.833 0.693 0.766 0.696 0.711 0.658 0.660 0.729 0.593 0.558 0.441

CB#149 4.26 3.52 2.90 3.20 3.05 2.97 2.89 2.81 3.04 2.59 2.74 1.96

CB#170 1.62 1.48 1.13 1.28 1.18 1.18 1.06 1.12 1.31 1.10 0.868 0.722

CB#183 0.841 0.785 0.59 0.683 0.64 0.654 0.598 0.581 0.729 0.559 0.517 0.386

CB#187 2.34 2.09 1.63 1.88 1.79 1.69 1.59 1.57 1.87 1.55 1.34 1.06

CB#18 3.87 3.00 3.25 3.08 2.87 3.88 4.58 2.23 2.97 1.90 3.07 1.62

CB#44 2.83 2.20 2.08 2.03 1.94 2.37 2.39 1.68 2.13 1.58 2.07 1.21

CB#47 1.15 0.959 0.821 0.841 0.848 0.913 0.85 0.725 0.838 0.731 0.792 0.522

CB#49 2.43 1.96 1.74 1.75 1.62 1.96 1.86 1.43 1.69 1.41 1.65 1.02

CB#66 4.71 3.65 3.12 3.38 3.10 3.34 3.00 2.82 3.31 2.84 2.73 1.99

CB#110 5.05 4.30 3.43 3.84 3.56 3.64 3.48 3.30 3.83 3.21 3.00 2.24

CB#158 0.484 0.413 0.329 0.365 0.342 0.354 0.329 0.308 0.391 0.314 0.292 0.218

CB#141 0.833 0.757 0.620 0.702 0.692 0.646 0.673 0.612 0.730 0.588 0.56 0.400

CB#151 1.13 1.00 0.827 0.861 0.883 0.819 0.823 0.734 0.922 0.768 0.753 0.491

CB#156 0.453 0.409 0.327 0.379 0.356 0.341 0.323 0.332 0.368 0.311 0.278 0.227

CB#194 1.05 0.869 0.661 0.781 0.754 0.662 0.607 0.690 0.848 0.647 0.527 0.434

SUM ICES7 31.3 27.0 21.7 23.5 22.3 23.1 23.3 20.4 23.1 20.0 19.9 13.9

SUM CB'S 72.0 60.8 50.7 54.3 51.3 54.6 54.4 46.2 53.7 44.8 46.1 31.8

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5 Discussion

5.1 Chemical contaminant assessment

Contaminant levels measured during chemical analysis are compared with Cefas Action Levels (MMO,

2015) in Table 8. Cefas Action Levels determine the suitability of dredged material for disposal at sea.

In general, where contaminant levels are;

• Below Action Level 1 – are of no concern and are unlikely to influence the licensing decision

• Between Action Level 1 and 2 – require further consideration before a decision can be made

• Above Action Level 2 – are generally considered unsuitable for sea disposal.

No contaminants were determined to be at or above Action Level 2 at any sampling station. Slight

exceedances of Action Level 1 were detected for PCBs, zinc, nickel, lead and chromium at all sites.

Slight exceedances of Action Level 1 were detected for cadmium and mercury at sampling station

HPCD06 only. Where Action Level 1 was exceeded, the measured concentrations were significantly

below Action Level 2 (by an order of magnitude) with the exception of zinc, for which the maximum

measured concentration was 262.18 mg.kg-1 (at station HPCD11) compared with the Cefas Action Level

2 for zinc of 800 mg.kg-1. The results are consistent with previously conducted analyses of seabed

sediment samples from the Severn Estuary near Hinkley Point, where background concentrations

typically exceed Action Level 1 (e.g. chromium concentrations up to 67 mg.kg-1; lead concentrations up

to 141 mg.kg-1; nickel concentrations up to 59 mg.kg-1; zinc concentrations up to 307 mg.kg-1 and PCB

concentrations up to 61 μg.kg-1 were measured in sediments collected near the HPC site in 2009

(BEEMS Technical Report TR186)).

The results of analyses conducted on the 2017 samples were also consistent with previous seabed

sediment samples from further afield in the Severn Estuary collected in 2004 and 2005 and reported in

Langston et al. (2010). The 2017 sample results were generally similar to or lower than those collected in

2004/5 for various metals (copper, nickel, cadmium and lead) and much lower than the reported

concentrations of copper, nickel and lead found in 2004/5 at some locations in the Severn Estuary

including Cardiff and Berrow.

PAH concentrations from the 2017 analyses were also compared with the 2004/2005 data. Data from

2004/5 were available for naphthalene, anthracene, fluoranthene and phenanthrene and the 2017

values were generally similar, but with much lower maximum values. The maximum concentration of

anthracene measured at the HPC intake and outfall locations in 2017, for example, was 234 µg.kg-1; In

the 2004/5 data anthracene concentrations at Cardiff in excess of 450 µg.kg-1 were detected.

Variations in the concentrations of metals, PCBs and PAHs between different samples (i.e. spatial and

temporal variation) occur for several potential reasons. Sample depth may affect the concentrations

measured; in the 2009 vibrocore samples, the deeper samples generally show low contaminant

concentrations with higher levels near the surface of the core. This is likely to result from the deposition

of the deeper sediments prior to the widespread release of anthropogenic contaminants into the marine

environment. The various surveys considered in this report (which involved sampling in 2004/5, 2009

and 2017) gathered samples from different locations which will have been exposed to different source

of contamination, and proximity to specific contaminant sources is likely to affect the local

concentrations. As well as different proximity to different contaminant sources, the sampling locations

will have different physical characteristics (for example water depth, tidal currents and wave climate)

which will play a role in the re-distribution of contaminant-bearing sediments. Temporal variations may

also relate to the introduction of control measures limiting the input of contaminants resulting in higher

concentrations in older samples and decreasing concentrations in later samples as the contaminant

degrades or disperses.

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Table 8 Action Levels determined according to contaminant levels. Values are in mg.kg-1. Green denotes contaminant level below Action Level 1. Yellow

denotes between Action Levels 1 and 2. Red denotes contaminant levels above Action Level 2.

Group Analysis

Action Level Sampling Station Concentrations measured

in 2009 samples1

1 2 HPC D06

HPC D07

HPC D08

HPC D09

HPC D10

HPC D11

HPC D12

HPC D13

HPC D14

HPC D15

HPC D16

HPC D17

Maximum Mean

Metals

Arsenic 20 100 30.00 14.75

Cadmium 0.4 5 0.46 1.50 0.25

Chromium 40 400 60.51 57.34 53.03 52.65 54.27 68.49 47.88 59.10 51.94 54.06 49.26 45.75 67.00 37.00

Copper 40 400 51.00 21.25

Lead 50 500 83.73 74.62 68.38 66.9 65.48 76.8 56.69 73.22 65.58 64.4 61.94 59.92 141.00 41.96

Mercury 0.3 3 0.34 0.67 0.23

Nickel 20 200 38.41 37.31 35.03 35.12 34.25 44.55 31.25 37.97 35.02 35.35 33.63 31.10 59.00 32.02

Zinc 130 800 245.42 227.33 210.02 208.04 203.15 262.18 181.65 232.42 204.87 202.60 193.20 179.85 307.00 125.84

Organotins 0.1 1

0.05 Not

applicable2

PCBs

Sum ICES7

0.01 None 0.0313 0.0270 0.0217 0.0235 0.0223 0.0231 0.0233 0.0204 0.0231 0.02 0.0199 0.0139 0.2148 0.0137

Sum CBs 0.02 0.2 0.0720 0.0608 0.0507 0.0543 0.0513 0.0546 0.0544 0.0462 0.0537 0.0448 0.0461 0.0318 0.6015 0.0388

1 2009 sediment samples were acquired and analysed and reported in BEEMS Technical Report TR186 (BEEMS, 2009). The concentrations measured for each substance

are provided in Table 7 for comparison with the latest results.

2 The majority of 2009 organotin analyses produced no detectable result and so no mean value was calculated.

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5.2 Radiological assessment

A conservative generic radiological assessment indicated that the doses of radioactivity from the sediment samples were below limits recommended by the IAEA (2003; 2004), and a subsequent more detailed case-specific assessment was not necessary (see Appendix A: Radiological Assessment of Dredging Application for Hinkley Point C Power Station, Somerset (2017)). The radiological results were consistent with previous analyses of sediment samples acquired in 2009 (BEEMS Technical Report TR186) and 2013 (Leonard et al., 2013). The activity levels recorded are so low that the sediment would not be defined as “radioactive material” or “radioactive waste” under the Environmental Permitting (England and Wales) (Amendment) Regulations (2011) or as described in the guidance on the scope of and exemptions from the radioactive substances legislation in the UK provided by Defra (Defra, 2011). The doses indicated by the assessment are shown in Table 9.

Table 9 Doses predicted by the IAEA generic radiological assessment (IAEA, 2003; 2004)

Type of dose Dose De minimis criteria (IAEA, 2003)

Individual members of a dredger crew 5.8 µSv/year 10 µSv/year

Individual members of the public 1.9 µSv/year 10 µSv/year

Collective dose to UK population 0.035 man Sv/year 1 man Sv/year

Under the London Convention of 1972, only materials below de minimis levels for radioactivity may be considered for disposal at sea. The IAEA describes a generic procedure for calculating individual and collective doses that could arise from the disposal of candidate material at sea (IAEA, 2003; 2004) which has then been adopted for use in the UK using the procedure described by McCubbin and Vivian (2006) to fulfil UK government’s responsibilities under the London Convention by producing estimates of individual and collective doses to dredge operators and the public.

The assessment undertaken for this 2017 survey for Marine Licence 12/45ML indicates that the doses of radioactivity that could potentially result from the disposal of the sediments analysed were well below the IAEA de minimis levels (see Table 9). Under the IAEA assessment procedure, therefore, no further assessment is required and there is no reason (from a radiological perspective) that the sediments should not be disposed of to sea.

The specific assessment undertaken for disposal of the sampled sediments to Cardiff Grounds was based on the generic parameters set out in McCubbin and Vivian (2006). Selected parameters are shown in Table 10.

Table 10 Selected parameters used in the generic assessment and (where available) local parameters for

Cardiff.

Parameter Value used in assessment

Local parameters for Cardiff (where available)

Source of local parameter data

Mass of candidate material dumped

100,000 tonnes 200,000 tonnes Marine Licence 12/45/ML

Individual ingestion rate of fish

50 kg / year 24 kg / year Environment Agency et al. 2017

Individual ingestion rate of crustacea

7.5 kg / year 3.8 kg / year Environment Agency et al. 2017

Individual ingestion rate of molluscs

7.5 kg / year Not significant Environment Agency et al. 2017

Ingestion rate of sediment 8 x 10-3 kg /year 2.5 x 10-3 kg /year Environment Agency et al. 2017

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The generic parameters used in the assessment consider a smaller mass of disposed material than

proposed but assume a much higher rates of seafood and sediment ingestion (Table 10). The

parameters used in the generic assessment are, therefore, suitable to determine the likely dose level

specifically for the proposed disposal activity at Cardiff grounds. As the generic assessment indicated

doses well below de minimis levels (see Table 9) no further assessment was necessary.

The collective dose to the public was 0.035 man Sv/year (Table 9), well below the IAEA de minimis level

for collective doses to populations of 1 man Sv/year. This calculation used the generic assessment

parameters from McCubbin and Vivian (2006) and refer to a stretch of coastline 10,000 m long with an

annual collective shore occupancy of 50 person hours/year/m (or a total collective exposure of 500,000

person hours/year). Given the extremely low collective dose to the public calculated (0.035 man Sv/year

compared with a de minimis level of 1 man Sv/year), no further site-specific assessment was deemed

necessary to check that de minimis levels would not be exceeded at Cardiff.

Full details of the methodology used to assess the sediment samples as safe for disposal at sea can be

found in McCubbin and Vivian (2006). The assessment showed that the potential individual dose of

radioactivity to the public from the disposal of the sediments collected and analysed in 2017 was 1.9

µSv/year, well below the de minimis limit recommended by the IAEA (10 µSv/year) and that no further

assessment of the radiological safety of disposing of the sediments to sea was required.

Comparison with previously analysed sediment samples

Before the 2017 sediment sampling described in this report, sediment samples were collected on two

previous occasions: in 2013 (see Appendix C: Radiological Analysis results from surface sediment

samples acquired in 2013 and analysed by Cefas.) when surface sediment samples were taken and in

2009 when sub-surface (and surface) sediment samples were collected using vibrocoring, and

radiological samples were acquired from depths below the seabed of up to 4.8m (see Appendix B:

Radiological Analysis results from vibrocore samples acquired in 2009 by Fugro Alluvial Offshore Ltd

using a 6m vibrocorer and analysed by Cefas.). Sediment cores were cut into sections and sub-samples

for radiological analysis were taken from the top and bottom sections to determine the radioactivity

content from both man-made and naturally-occurring radioactivity.

In the surface samples, the levels of radioactivity were low and many of the man-made elements (i.e.

americium-241 and cobalt-60) were undetectable (i.e. any activity was below the analytical detection

limit). Levels of caesium-137 (man-made) were positively detected, and were generally similar over time

and between individual sampling locations. The caesium-137 levels are also consistent with previous

data reported for Hinkley Point by an analytical laboratory operated by Environmental Scientifics Group

(ESG, now re-named SOCOTEC) and reported in the annual report series ‘Radioactivity in Food and the

Environment’ (Cefas, 2017). The levels of the positively detected man-made elements (i.e. caesium-137

and americium-241) in these samples were typical of muddy sediments from the combined effects of

discharges from the Hinkley Point Power station, other nuclear establishments discharging into the

Bristol Channel and weapons testing (and possibly a small Sellafield derived component). As expected,

levels of naturally- occurring radioactivity (i.e. potassium-40, radium-226, thorium-232 and uranium-238)

were positively detected and were also generally similar in time and across sampling locations.

Levels of all man-made elements were below the analytical detection limit (i.e. not detectable) in sub-

surface sediments collected in 2009. Potassium-40 (naturally-occurring) results were lower at depth (sub-

surface), indicating that the particle size of sediments was finer at the surface (i.e. higher radioactivity

levels are more likely at the surface because of the sediment composition). Data from both 2013 and

2017 were used to determine the risk from radioactivity. On both occasions, a conservative assessment

procedure indicated that doses received were contributed to mostly from naturally-occurring radioactivity,

that doses were well below recommended limits, and that a subsequent more detailed case-specific

assessment was, therefore, not necessary (in line with IAEA (2003) guidelines).

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6 Conclusions

Surface sediment sampling has been carried out at the HPC intake and outfall locations in accordance with

the monitoring plan approved by NRW (BEEMS technical report TR415) to address condition 9.4 of (NRW)

Marine Licence 12/45/ML.

Chemical analysis of the sediment samples indicates no reason that the material should not be disposed of

to sea.

Conservative generic radiological assessment (IAEA, 2003; 2004) indicated that doses received were below

recommended limits, and a subsequent, more detailed case-specific assessment is not necessary. There is

therefore no radiological reason why this material should not be disposed of to sea

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7 References

BEEMS Technical Report 186; Predicted Effects of NNB on Water Quality at Hinkley Point September 2011.

Cefas, Lowestoft Suffolk.

BEEMS Technical Report TR415; Hinkley Point C – Intake and outfall pre-disposal sediment sampling

scheme November 2016. Cefas, Lowestoft Suffolk.

Cefas (2017). RIFE - 22 Radioactivity in Food and the Environment 2016. Compiled by the Centre for

Environment, Fisheries and Aquaculture Science (Cefas) on behalf of the Environment Agency, Food

Standards Agency, Food Standards Scotland, Natural Resource Wales, Northern Ireland Environment

Agency and the Scottish Environment Protection Agency. Cefas, Lowestoft Suffolk.

Defra (2011) Guidance on the scope of and exemptions from the radioactive substances legislation in the

UK. Guidance Document. September 2011, Version 1.0.

Environment Agency, FSA, FSS, NIEA, NRW and SEPA 2017. Radioactivity in Food and the Environment,

2016. RIFE 22. Environment Agency, FSA, FSS, NIEA, NRW and SEPA, Bristol, London, Aberdeen,

Belfast, Cardiff and Sterling.

Environmental Permitting (England and Wales) (Amendment) Regulations 2011. Statutory Instruments 2011

No. 2043 11th August 2011.

IAEA (2003). Determining the suitability of materials for disposal at sea under the London Convention 1972:

A radiological assessment procedure. TECDOC-1375, IAEA, Vienna.

IAEA (2004). Sediment distribution coefficients and concentration factors for biota in the marine environment.

Tech. Rep. Ser. No. 422, IAEA, Vienna.

Langston W.J., Pope N.D., Jonas P.J.C., Nikitic C., Field M.D.R., Dowell B., Shillabeer N., Swarbrick R.H.

and Brown A.R. (2010). Contaminants in fine sediments and their consequences for biota of the Severn

Estuary. Marine Pollution Bulletin Volume 61, Issues 1–3, 2010, Pages 68-82.

Leonard K.S., Smedley P.A. and Cogan S.M. (2013). Radiological Assessment of Dredging Application for

Hinkley Point C Power Station, Somerset (2013). Cefas Environment Report RL 05/13.

McCubbin D. and Vivian C. M. G. (2006). Dose assessments in relation to disposal at sea under the London

Convention 1972: judging de minimis radioactivity, Cefas Environment report RL05/06.

MMO (2015). High Level Review of Current UK Action Level Guidance. A report produced for the Marine

Management Organisation, pp 73. MMO Project No: 1053. ISBN: 978-1-909452-35-0.

Natural Resources Wales (2014). Marine and Coastal Access Act 2009: Part 4 – Marine Licencing, Marine

Licence: 12/45/ML.

Natural Resources Wales (NRW) (2017). Personal communication. E-mail from NRW Marine Licensing

([email protected]) to Stephen Roast (NNB GenCo), 13th January 2017.

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https://beems.cefas.co.uk/beems/hinkley-point-reports/tr415hinkley-point-c-intake-and-outfall-pre-disposal-sediment-sampling-scheme-november-2016-prel-d/




http://www.sciencedirect.com/science/journal/0025326X/61/1

mailto:[email protected]



Appendix A: Radiological Assessment of Dredging

Application for Hinkley Point C Power Station, Somerset

(2017) A -

ACCEPTED



Radiological Assessment of

Dredging Application for

Hinkley Point C Power Station,

Somerset (2017)

Cefas Environment Report RL 05/17

(Cefas contract C7292H)

Kins Leonard, Paul Smedley and Steph Cogan

June 2017

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RADIOLOGICAL ASSESSMENT OF DREDGING APPLICATION FOR HINKLEY POINT C POWER STATION, SOMERSET (2017)

SUMMARY

In 2012, NNBGenCo (a subsidiary of EDF Energy) lodged a Marine and Coastal Access Act (MCAA) licensing application to carry out a variety of dredging scenarios, within which dredging and disposal could occur at Hinkley Point C. Sediment samples were acquired in 2017 to fulfil condition 9.4 of Marine Licence 12/45ML. The volume of material to be dredged and disposed of at sea is approximately 200,000 tonnes.

In England, the MMO administers a range of statutory controls that apply to marine works on behalf of the Secretary of State for Environment, Food and Rural Affairs (Defra), this includes issuing licences under the Marine and Coastal Access Act (MCAA), 2009 (United Kingdom - Parliament, 2009) for the disposal of dredged material at sea. Licences for disposals made in Scottish waters and around the coast of Northern Ireland are the responsibility of the Scottish Government (Marine Scotland) and the Department of Environment (NIEA) respectively. As of 1st April 2010, licences for Welsh waters are the responsibility of the Welsh Government, administered by Natural Resources Wales from 1st April 2014.

Using the conservative generic radiological assessment procedure developed by the IAEA, to convert radionuclide concentrations in dumped material into radiation doses due to dumping, the derived total doses to individual members of the crew and public were 5.8 µSv/year and 1.9 µSv/year, respectively. The total collective dose was

0.035 manSv/year. The values for individual members of the crew and public, and the collective dose, were within the de minimis criteria of 10 µSv/year (individual doses) and 1 manSv/year (collective dose), respectively.

Since the conservative generic radiological assessment procedure indicated that doses received were below recommended limits, a subsequent more detailed case- specific assessment was not necessary. Therefore, from radiological considerations, there is no objection to this material being dredged and disposed of at sea.

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ASSESSMENT DETAILS

In 2012, NNB GenCo (a subsidiary of EDF Energy) lodged a MCAA licensing application to carry out a variety of dredging scenarios for the intakes and outfalls jetty application, within which dredging and disposal could occur at Hinkley Point C. The application was updated in 2017. The volume of material to be dredged and disposed of at sea is approximately 200,000 tonnes.

As part of the radiological assessment of the proposed operation, 12 sediment grab samples were taken (at the sediment surface) on from the vessel “Titan Endeavour” on the 2nd May 2017, sample positions given in Table A1 and shown in Figure A1.

Table A1. Sample positions from Hinkley Point C

Sample

Identifier

Lat/Long

Easting Latitude

Northing Longitude

HPCD06 51 13.316N 03 09.561W

HPCD07 51 13.298N 03 09.578W

HPCD08 51 13.250N 03 09.523W

HPCD09 51 13.267N 03 09.505W

HPCD10 51 14.074N 03 10.150W

HPCD11 51 14.053N 03 10.189W

HPCD12 51 13.985N 03 10.579W

HPCD13 51 13.956N 03 10.581W

HPCD14 51 13.882N 03 10.433W

HPCD15 51 13.895N 03 10.403W

HPCD16 51 13.966N 03 10.029W

HPCD17 51 13.999N 03 10.034W

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Figure A1. Location Site Map

Following freeze-drying and homogenisation, radionuclide assay at the Cefas

Lowestoft Laboratory was achieved by counting samples on a high purity Ge detector. The results are summarised in Table A2.

The specific activity of the artificial radionuclides (e.g. 137Cs and 241Am) in these samples was typical of muddy sediments from the combined effects of discharges from the Hinkley Point Power station, other nuclear establishments discharging into the Bristol Channel and weapons testing (and possibly a small Sellafield derived component), being enhanced above background levels outside the Irish Sea.

Results are also similar to those reported in a previous sampling campaign at Hinkley Point C (Leonard et al., 2013) which supported the disposal application in question (12/45ML). The Sellafield component is a legacy of large discharges from the Sellafield Limited reprocessing plant (formally British Nuclear Fuels) at Sellafield in the 1970s.

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Table A2. Radioactivity in sediment dredged from Hinkley Point C, 2017

Sample Identifier

Specific activity (Bq/kg, dry weight)

60Co 137Cs 226Ra

(via 214Pb)

232Th

(via 228Ac)

238U

(via 234Th)

241Am

HPCD06 < 0.4 19.5 23.0 37.4 62.2 < 1.46

HPCD07 < 0.4 19.5 22.3 37.9 57.5 < 1.57

HPCD08 < 0.4 17.9 21.8 33.0 66.3 < 1.42

HPCD09 < 0.4 17.5 23.2 32.4 54.3 < 1.57

HPCD10 < 0.5 14.9 19.8 28.9 41.8 < 1.68

HPCD11 < 0.3 14.7 21.4 29.7 48.7 < 1.12

HPCD12 < 0.4 15.1 21.7 28.9 45.8 < 1.38

HPCD13 < 0.4 15.1 21.7 29.1 51.7 < 0.59

HPCD14 < 0.5 14.8 21.7 26.6 48.6 < 0.62

HPCD15 < 0.4 14.8 23.1 28.2 49.0 < 1.41

HPCD16 < 0.4 12.8 23.8 29.5 46.7 < 1.52

HPCD17 < 0.4 13.7 22.0 29.5 46.8 < 1.36

*Average 0.4 16 22 31 52 1

*Average determinations use < results as positively measured values to produce a conservative estimate

In addition to the nuclides detected by gamma spectrometry, sediments are also known to contain activities of Pu radionuclides. The 241Am data were used to derive estimates for 239,240Pu and 241Pu, assuming their activity was proportional to the ratio in the time-integrated Sellafield discharges. This approach is reasonable given that both radionuclides are highly particle-reactive, hence the fate following discharge is similar. The activity for 210Pb was derived using data for 226Ra and assuming secular equilibrium.

Under the London Convention, only materials with de minimis levels of radioactivity may be considered for disposal at sea. The IAEA describe a generic procedure for calculating individual and collective doses that could arise from the disposal of candidate material at sea (IAEA, 2003; 2004). In the UK, the IAEA methodology was adopted using the published procedure described by McCubbin and Vivian (2006). The IAEA radiological assessment procedure (IAEA, 2003) was further developed to fulfil the responsibilities of the UK government towards the London Convention of 1972

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to produce estimates of individual and collective dose to dredge operators and the public (McCubbin and Vivian, 2006).

Using the conservative generic radiological assessment procedure developed by the IAEA (IAEA, 2003; 2004), to convert radionuclide concentrations in dumped material into radiation doses due to disposal at sea, the derived total doses to individual members of the crew and public were 5.8 µSv/year and 1.9 µSv/year respectively. The total collective dose was 0.035 manSv/year. The values for individual members of the crew and public, and the collective dose, were within the de minimis criteria of 10 µSv/year (individual doses) and 1 manSv/year (collective dose), respectively.

The dose estimates for individual crew/public (by nuclide), derived using the generic IAEA model, are shown in Figure A2.

Figure A2. Assessment of dose to individual members of crew and the public arising from Hinkley Point Power Station (Doses were derived using average activities listed in Table A2).

Since the conservative generic radiological assessment procedure indicated that doses received were well below recommended limits, a subsequent more detailed case-specific assessment was not necessary. All the derived total dose values were less than the de minimis criteria of 10 µSv/year and 1 manSv/year for individual and collective dose, respectively. Therefore, from radiological considerations, there is no objection to this material being dredged and disposed of to sea.

Natural Series Artificials

Individual crew

Individual public

Do

se (

µS

v/a

)

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NOT PROTECTIVELY MARKED 35 of 39

REFERENCES

IAEA (2003). Determining the suitability of materials for disposal at sea under the London Convention 1972: A radiological assessment procedure. TECDOC-1375, IAEA, Vienna.

IAEA (2004). Sediment distribution coefficients and concentration factors for biota in the marine environment. Tech. Rep. Ser. No. 422, IAEA, Vienna.

Leonard, K.S., Smedley, P.A. and Cogan, S.M. (2013). Radiological Assessment of Dredging Application for Hinkley Point C Power Station, Somerset (2013). Cefas Environment Report RL 05/13.

McCubbin D. and Vivian C. M. G. (2006). Dose assessments in relation to disposal at sea under the London Convention 1972: judging de minimis radioactivity, Cefas Environment report RL05/06.

United Kingdom - Parliament, 2009. Marine and Coastal Access Act, 2009. HMSO, London.

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About us

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Appendix B: Radiological Analysis results from vibrocore samples acquired in

2009 by Fugro Alluvial Offshore Ltd using a 6m vibrocorer and analysed by

Cefas.

Customer: Fugro Alluvial Offshore Ltd Contract / Sub-contract No: C3630 Type of analysis: Gamma Spectrometry

Description of sample(s): Sediment core samples Date of receipt of sample(s): Nov-09

Description of methods of analysis used: Radionuclide concentration by drying Date of analysis: Dec-09

Report authorised by: Dr Kins Leonard & Steph Cogan Date: 18/12/09

The results follow and relate only to the samples as indicated

Sampled date

Sample Lsn

Depth m1 VC No2

Am-241 %error Co-60 %error Cs-137 %error K-40 %error Ra-226 %error Th-232 %error U-238 %error

09/11/2009 1230 0.0 - 1.0 VCJ9 <0.67 *- <0.40 *- 23.52 4.53% 673.0 3.92% 25.25 5.88% 29.71 5.64% 48.73 7.49%

09/11/2009 1231 4.35 - 4.42 VCJ9 <1.24 *- <0.30 *- <0.30 *- 580.0 3.88% 27.65 6.43% 33.29 5.19% 46.13 8.84%

09/11/2009 1232 0.0 - 1.0 VC17 <1.38 *- <0.30 *- 36.73 4.37% 654.0 3.87% 24.46 6.22% 33.78 5.37% 43.98 8.11%

09/11/2009 1233 3.00 - 3.08 VC17 <0.62 *- <0.30 *- <0.30 *- 584.0 3.91% 71.25 5.40% 29.32 5.53% 71.23 6.19%

15/11/2009 1234 0.0 - 1.0 VC9 0.65 38.19% <0.40 *- 26.27 4.48% 664.0 3.90% 22.43 6.17% 29.47 5.57% 39.46 7.80%

15/11/2009 1235 4.70 - 4.80 VC9 <0.54 *- <0.30 *- <0.30 *- 614.0 3.89% 30.30 5.64% 40.73 5.03% 41.25 6.67%

15/11/2009 1236 0.0 - 1.0 VC36 <0.42 *- <0.50 *- 0.98 24.57% 370.0 4.16% 15.56 7.35% 22.36 7.19% 30.83 8.48%

15/11/2009 1237 1.94 - 2.16 VC36 <0.51 *- <0.30 *- <0.30 *- 480.0 3.93% 29.10 5.64% 27.32 5.43% 50.90 7.04%

17/11/2009 1238 0.0 - 1.0 VCJ20R <1.37 *- <0.30 *- 43.14 4.35% 674.0 3.87% 25.29 6.09% 33.10 5.36% 50.25 9.94%

17/11/2009 1239 3.00 - 4.12 VCJ20R <0.63 *- <0.40 *- <0.30 *- 480.0 3.95% 73.57 5.39% 25.85 5.62% 68.56 6.34%

Comments: All results are expressed as Bq/kg dry

< indicates that the result is below the limit of detection of the counting equipment.

% error indicates 1 sigma Total uncertainty

* inapplicable when result is below detection limit.

This report shall not be reproduced except in full without written approval of Cefas Radioanalytical Service

Excel Test Report Form: Version 1 Issue date: 2 January 2007 Authorised by: Bryn Jones Page 1 of 1 1 Samples VC 17 and VC36 were taken at the planned 2 HPC intake locations, VC9 was from the planned HPC outfall location. (VCJ samples were taken from further inshore at the planned jetty location).

2 The depths refer to the depth in metres of the section of sediment core which was sub-sampled for radiological analysis. These depths were incorrectly

labelled in TR186 as cm, and the error is corrected here.

A - ACCEPTE

D



Appendix C: Radiological Analysis results from

surface sediment samples acquired in 2013 and

analysed by Cefas.

Sample

Identifier

Specific activity (Bq/kg, dry weight)

60Co

137Cs

226Ra

(via 214Pb)

232Th

(via 228Ac)

238U

(via 234Th)

241Am

In/Out (MCU 12/45)

Sample 1 <0.43 21.7 23.1 28.4 45.4 <1.51

In/Out (MCU 12/45)

Sample 2 <0.40 27.4 22.3 26.5 43.3 <1.62

In/Out (MCU 12/45)

Sample 3 <0.44 17.4 20.6 24.5 40.6 0.63

In/Out (MCU 12/58)

Sample 4 <0.25 7.2 11.2 13.8 19 <0.96

In/Out (MCU 12/45)

Sample 5 <0.44 32.2 26 34.2 41.5 <1.64

In/Out (MCU 12/45)

Sample 6 <0.42 23.3 23.8 30.6 43.3 <1.49

In/Out (MCU 12/45)

Sample 7 <0.45 20.5 24 28 32.5 <1.57

In/Out (MCU 12/45)

Sample 8 <0.41 18.9 23.4 26.2 45.7 <1.50

In/Out (MCU 12/45)

Sample 9 <0.45 20.8 24.1 26.2 44.4 <1.62

In/Out (MCU 12/45)

Sample 10 <0.46 22.1 22.2 25.7 38.7 <1.71

In/Out (MCU 12/45)

Sample 11 <0.44 23 23.9 26.4 42.2 <1.56

In/Out (MCU 12/45)

Sample 12 <0.41 18.5 21.8 26.8 42.4 <1.45

In/Out (MCU 12/58)

Sample 1 <0.43 20.1 24.4 27.2 39.9 <0.71

In/Out (MCU 12/58)

Sample 2 <0.43 21.2 22.6 25.7 42.8 <1.59

In/Out (MCU 12/58)

Sample 3 <0.49 19.4 23.5 25.9 41 0.97

In/Out (MCU 12/48)

Sample 4 <0.45 21.2 24.2 28.4 39 3.16

In/Out (MCU 12/58)

Sample 5 <0.45 21.7 24.5 27.4 44.4 <0.66

*Average 0.43 21 23 27 40 1.59

*Average determinations use < results as positively measured values to produce a conservative estimate.

A - ACCEPTE

D

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