Hinkley radioactive mud: brief to Senedd Petitions Committee 17 April 2018

Petition P-05-785 Suspend Marine License 12/45/ML

Comments on NRW response of 27 March, from Friends of the Earth, Barry&Vale. 

We formulated a briefing earlier, on the basis of our FoI request to NRW for all documents relating to this license application held by them.  We are therefore confident that we have viewed most of the background material.  We enclose that briefing for use of the Committee and add the following re the latest NRW letter to you.

Contrary to NRW we see the Sampling of sediment as not primarily for public reassurance, as stated, but to meet licensing requirements.  Sampling at depth, as the Committee requested, is likewise needed to meet licensing requirements: Licence Condition 9.5 requires satisfying NRW that the material is suitable for deposit at the site.

1. The applicant’s refusal of deep samples is unacceptable.  

It depends on NRW’s statement “there is no scientific basis for any additional sampling” which is false.  The Committee were wrongly told earlier there is no scientific evidence of higher radioactivity in deeper sediments in the Hinkley Point area. (as on the NRW website).  The evidence is clear in the 2009 data for U238 and Radium, as in the reduced Table below: the numbers show 3 out of the 5 samples were significantly higher at depth (up to 3x for Radium - Ra). 

2. No specialist/expert assessment by Welsh authorities

   "we consulted Public Health Wales and NRW’s own internal expert in relation to the dose analysis results" 
 No report is provided (no transparency); this sentence refers only to the radiological dose, not to the chemical constituents.

3. The de minimis criteria are for disposal at sea. 

The IAEA-TECDOC-1375 defines this to include well-mixed near-coastal waters

“The disposal is assumed to take place a few kilometres off the coast so the actual shape of the coastline does not influence the dispersion significantly.”

The Severn Estuary site is not “sea” , but estuarial water with distinct circulation and ecology, which does not satisfy the IAEA criterion. 

4. Disposal in the Estuary requires information on dispersal of the radioactivity and use of a habits survey to calculate collective dose.  Cefas use a habits survey from the Cumbrian shore for sea-food consumption and beach-combers/recreation. The Severn Estuary is very different and sea-land transfer potentially much stronger.

5. the NRW letter does not cover the chemical contaminants, though they are required to assess their impacts.  Their Website says: Chemical contaminants were assessed against Cefas Action Levels[2]   UK guidelines to assess dredged material and its suitability for disposal to sea.   Several metal and organic contaminants were measured as above Action Level-1, yet no assessment has been made by NRW.

6. CEFAS say Dredged material with contaminant levels between Action Levels 1 and 2 requires further consideration and testing before a decision can be made.

The documents show no further assessment – which of course must be against the characteristics of the dump site and conducted under criteria relevant to it.  For this European “Special Area of Conservation”, criteria from biodiversity/Habitat legislation obviously come in, but none have been considered.  The end-fate of the contaminants must also enter, requiring consideration of the cited studies on deposition on the estuarial mud flats and transfer to marine life and to the land.

7. The Licence conditions 9.5, 9.11 require that the sediments are suitable for deposit and that dispersal via re-suspension should be avoided.  It’s not shown how this could be done in practice.  Discharge is planned by dropping from the barge, but the only way to ensure “deposit” of the bulk of the material is to discharge via pipe to the sea bottom at tidal extremes and minimising re-suspension requires cover with heavy material before inter-tidal currents become strong.

9.5. The Licence Holder must ensure that no material is deposited after 4th March 2016 without written confirmation from NRW, acting on behalf of the Licensing Authority, that they are satisfied the material is suitable for deposit at site LU110.

9.11. The Licence Holder must ensure that best practice is used to minimise re-suspension of sediment during these works.

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Data for U238 and Radium in 2009 samples taken at depth

3 out of the 5 samples were significantly higher at depth (up to 3x for Radium - Ra).  The NRW failure to require deep samples means only the 2009 data are representative of the bulk of the material to be dredged.  As there are so few data, the maximum plus a safety factor has to be adopted.  This raises CEFAS’s 5.8 μSv/yr calculated level, potentially to above the 10 μSv/yr limit.

Table B.15  Uranium-238 and Radium-226 concentrations for Vibro core samples  (also in [1] Appx B)

FUGRO survey of five locations in vicinity of intake, outfall and jetty, on 9/11 and 15/11 2009

Sample          U: surface/deep    Ra: surface/deep    depth           Date

1230/1231      48.73 / 46.13     25.25 / 27.65     4.35-4.42m      9/11

1232/1233      43.98 / 71.23     24.46 / 71.25     3.0-3.08m        9/11

1234/1235      39.46 / 41.25     22.43 / 30.30     4.7-4.8m          15/11

1236.1237      30.83 / 50.9       15.56 / 29.10     1.94-2.16m      15/11

1238/1239      50.65 / 68.56     25.29 / 73.57     3.0-4.12m        15/11

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