When nuclear reactors are refueled, a 12-hour spike in radioactive emissions exposes local people to levels of radioactivity up to 500 times greater than during normal operation, writes Ian Fairlie. The spikes may explain infant leukemia increases near nuclear plants – but operators provide no warnings and take no measures to reduce exposures.
On 23rd August, The Ecologist published very clear evidence of increased cancers among children living near nuclear power stations around the world, including the UK.
The story sparked much interest on social media sites, and perhaps more importantly, the article’s scientific basis (published in the academic peer-reviewed scientific journal the Journal of Environmental Radioactivity) was downloaded over 500 times by scientists.
Given this level of interest and the fact that the UK government is still pressing ahead with its bizarre plans for more nuclear stations, we return to this matter – and examine in more detail an important aspect which has hitherto received little attention: massive spikes in radioactive emissions from nuclear reactors.
Refueling releases a huge radioactive emissions plume
Operating nuclear power plants (NPPs) contain large volumes of radioactive gases at high pressures and temperatures. When their reactors are depressurised and opened to refuel every 12-18 months, these gases escape creating a spiked emission and a large radioactive plume downwind of the station lasting for 12 hours or so.
In 2011, the UK National Dose Assessment Working Group published guidance on ‘Short Term Releases to the Atmosphere‘. This stated that “…doses from the assessment of a single realistic short-term release are a factor of about 20 greater than doses from the continuous release assessment.”
An older German study (Hinrichsen, 2001) indicated that these doses could be 100 times greater. (Hinrichsen K (2001) Critical appraisal of the meteorological basis used in General Administrative Regulations (re dispersion coefficients for airborne releases of NPPs) See Annex D page 9: Radiation Biological Opinion (in German).
A dramatic increase in individual doses
Some scientists think that the time pattern is unimportant and only the population dose is relevant, but this turns out not to be the case. The reason is partly related to the duration of the release, as short releases produce very narrow plumes (plume widths vary non-linearly as a fractional power of the duration).
The result is that individual doses increase dramatically per Bq emitted. Another reason is that spikes result in high concentrations of organically bound tritium and carbon-14 in environmental materials and humans which have longer retentions and thus higher doses.
The precise amount will depend on many factors, including source term, proximity to the reactor, wind speed, wind direction, and the diets and habits of local people.
‘Especially at risk are unborn children’
IPPNW Germany warned of the probable health impacts of such large emission spikes. Dr Reinhold Thiel, a member of the German IPPNW Board said:
“Especially at risk are unborn children. When reactors are open and releasing gases, pregnant women can incorporate much higher concentrations of radionuclides than at other times, mainly via respiration. Radioactive isotopes inhaled by the mother can reach the unborn child via blood with the result that the embryo/ fetus is contaminated by radioactive isotopes.
“This contamination could affect blood-forming cells in the bone marrow resulting later in leukemia. This provides a plausible explanation for the findings of the KiKK study published in 2008 that under-fives living near NPPs are considerably more at risk of cancer, particularly leukemia, than children living further away.”
In the light of the German data, it is recommended half-hourly emissions data from all UK reactors should be disclosed and that the issue of childhood cancer increases near NPPs be re-examined by the Government.
Nuclear operators should inform local people when they intend to open up their reactors, and they should only do so at night-time (when most people are indoors) and when the winds are blowing out to sea.
- A hypothesis to explain childhood cancers near nuclear power plants via Journal of Environmental Radioactivity