Nuclear Theddlethorpe 03
Geology is what counts.
Useful summaries of the Theddlethorpe area’s geology are to
be found in RWM’s own reports, commissioned from the British Geological Survey, ‘Eastern England Regional Geology’ (EERG)
and ‘Eastern England Subregion 2’ (EES2).
It’s worth noting that we do know quite a lot about the geology of the region. This from page 3 of EERG:
“There are more than 690 boreholes drilled to more than 1,000m depth in search of coal, oil and gas, water and mineral salts (evaporites). This information is also supplemented by extensive geophysical investigations including studies of the Earth’s gravity and magnetic fields and seismic surveys. The distribution of rocks in this region is therefore reasonably well known at the national scale. There are a number of shallower boreholes that provide information on groundwater above 200m, but very little information within and deeper than the depth range of interest for a GDF, 200 to 1,000m below NGS datum.”
The sequence of rocks is summarised in Figure 2, page 8 of
EERG. The sedimentary rocks comprise various layers of pervious rocks such as
sandstones and impervious clays and mudstones. Nuclear waste would need to be
stored within a sufficiently thick layer of impervious rock and even if too
thin to hold a depository, thinner impervious layers higher in the sequence
might help seal lower layers from groundwater movement.
There are various possibilities but the mudstones of the Triassic, such
as the Mercia Mudstone Group, are probably the most obvious target for a GDF.
It is one thing finding a rock layer that is sufficiently impervious to movement of water (and hence radionucleotides) and might therefore provide a safe location for a GDF, but the issue in our area is what else is present. If there is a likelihood that material useful to a future civilisation is present, such as oil, gas or coal, the location will be unsuitable, as a future search for these resources could inadvertently breach the integrity of a nuclear waste depository.
There are hydrocarbons in rocks at a number of horizons
right down to the underlying Carboniferous rocks where we find the Coal
Measures. Gas has been found in commercially exploitable quantities at
Saltfleetby, 7km from the old Theddlethorpe Gas Terminal, and oil at Keddington. Coal
underlies the whole area and although too deep to be mined by conventional
means, underground coal gasification has been seriously considered. There is
currently no commercial interest in exploiting this resource and the climate
crisis demands an end to burning fossil carbon but we cannot know what the
people in future centuries may do and what technologies they may have. It is
not enough to say that while there is gas at Saltfleetby, the gas field does not
extend to Theddlethorpe. A future civilisation may have technologies that make
our enhanced recovery methods appear primitive. They may exploit resources that
we would consider worthless.
The existence of fossil carbon in the rocks below Theddlethorpe
must mean that this is rejected as a location for a GDF.
But don’t just take my word for it. These two passages are
from EES2:
Page 1. "There are known gas resources at Saltfleetby north of
Mablethorpe. In this area the drilling is likely to have affected the way in
which water moves through the rock. Also possible exploration in the future in
this area means that it is more likely that future generations may disturb a
facility. Parts of this subregion have Petroleum Exploration & Development
Licences to allow companies to explore for oil and gas. This exploration is
currently at an early stage and it is not known whether oil or gas in these
licence areas will be exploited. RWM will continue to monitor how this
exploration programme progresses. Parts of this area, immediately off the coast
and in the Humber estuary, are Coal Authority Licence Areas allowing companies
to explore for coal. It is not known whether coal in these licence areas will
be exploited. RWM will also continue to monitor how this exploration programme
progresses."
Page 4. "Resources There is a small gas field at Saltfleetby,
just north of Mablethorpe (Figure 4a). It is less likely that this area would
be suitable to host a GDF because borehole drilling associated with oil and gas
exploration affects the way in which water moves through the rocks. It also
presents a higher likelihood of inadvertent human intrusion in the future.
These known resources would be taken into account in the siting of a GDF.
Petroleum Exploration and Development Licences3 are currently held for much of
the onshore part of this subregion and a small part of the inshore are (Figure
4a). There are also Coal Authority Licence Areas, in 2 inshore parts of this
subregion off Hornsea and Mablethorpe (Figure 4b) and the Humber estuary
between Kingston upon Hull and Grimsby. It is not known whether coal, oil or
gas in these licence areas will be exploited, but they would need to be
considered in the siting of a GDF."
It is clear that RWM have a policy of rejecting a site where there is a likelihood
of fossil carbon resources. It is also clear that RWM know that there are
fossil carbon resources beneath Theddlethorpe. Which begs the question why are
they even bothering here?
Part One of this topic.