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The results of the studies carried out in France since
2005 and published by ASN in January 2010, as well
as the studies received since then, show that 85% of the
doses received by workers in the industries concerned
remained below 1 mSv/year. The industrial sectors in
whichworker exposure is liable to exceed 1mSv/year are
the following: titanium ore processing, heating systems
and recycling of refractory ceramics, maintenance of
parts comprising thorium alloys in the aeronautical
sector, chemical processing of zircon ore, mechanical
transformation and utilisation of zircon and processing
of rare earths.
3.1.3 Flight crew exposure to cosmic radiation
Airline flight crews and certain frequent flyers are exposed
to significant doses owing to the altitude and the intensity
of cosmic radiation at high altitude. These doses can
exceed 1 mSv/year.
The “SIEVERT” observation system set up by DGAC
(General Directorate for Civil Aviation), IRSN, the Paris
Observatory and the Paul-Émile Victor French Institute
for Polar Research
(www.sievert-system.com)
, is used to
estimate flight crew exposure to cosmic radiation on the
flights they make during the course of the year.
The doses received by 18,110 flight crewmembers were
recorded in SISERI in 2014. The individual doses are
less than 1 mSv in 15.3% of cases and between 1 mSv
and 4 mSv in 84.7% of cases.
3.2 Doses received by the population
3.2.1 Doses received by the population as a result
of nuclear activities
The automated monitoring networks managed
nationwide by IRSN
(Téléray, Hydrotéléray
and
Téléhydro
networks) offer real-time monitoring of environmental
radioactivity and can highlight any abnormal variation.
In the case of an accident or incident leading to the
release of radioactive substances, these measurement
networks would play an essential role by providing
data to back the decisions to be taken by the authorities
and by notifying the population. In a normal situation,
they contribute to the evaluation of the impact of BNIs
(see chapter 4).
However, there is no overall monitoring system able
to provide an exhaustive picture of the doses received
by the population as a result of nuclear activities.
Consequently, compliance with the population exposure
limit (effective dose set at 1 mSv per year) cannot
be controlled directly. However, for BNIs, there is
detailed accounting of radioactive effluent discharges
and radiological monitoring of the environment is
implemented around the installations. On the basis
of the data collected, the dosimetric impact of these
discharges on the populations in the immediate vicinity
of the installations is then calculated using models for
simulating transfers to the environment. The dosimetric
impacts vary, according to the type of installation and
the lifestyles of the reference groups chosen, from a few
microsieverts to several tens of microsieverts per year.
There are no known estimates for nuclear activities
other than Basic Nuclear Installations, owing to the
methodological difficulties involved in identifying the
impact of the facilities and in particular the impact
of discharges containing small quantities of artificial
radionuclides resulting from the use of unsealed
radioactive sources in research or biology laboratories,
or in nuclear medicine units. To give an example, the
impact of hospital discharges could lead to doses of
a several tens of microsieverts per year for the most
exposed persons, particularly for certain jobs in sewage
networks and wastewater treatment plants (IRSN studies
2005 and 2015).
Situations inherited from the past, such as atmospheric
nuclear tests and the Chernobyl accident, can make a
marginal contribution to population exposure. Thus
the average individual effective dose currently being
received in metropolitan France as a result of fall-out
from the Chernobyl accident is estimated at between
0.010 mSv and 0.030 mSv/year (IRSN 2001). That due
to the fall-out from atmospheric testing was estimated
in 1980 at about 0.020 mSv. Given a decay factor of
about 2 in 10 years, current doses are estimated at well
below 0.010 mSv per year (IRSN, 2006). With regard
to the fall-out in France from the Fukushima Daiichi
accident (Japan), the results published for France by
IRSN in 2011 show the presence of radioactive iodine at
very low levels, resulting in very much lower doses for
the populations than those estimated for the Chernobyl
accident, and having negligible impact.
3.2.2 Exposure of the population to NORM
(Naturally Occurring Radioactive Materials)
Exposure due to natural radioactivity in drinking
water.
The results of the Regional Health Agencies’
monitoring of the radiological quality of the tap water
distributed to consumers between 2008 and 2009
(DGS/ASN/IRSN report published in 2011) showed
that 99.83% of the population receives tap water
whose quality complies at all times with the total
indicative dose of 0.1mSv/year set by the regulations.
This overall assessment can also be applied to the
radiological quality of packaged mineral waters and
spring waters produced in France (DGS/ASN/IRSN
report published in 2013).
Exposure due to radon.
Since 1999, it is compulsory
to take periodic radon measurements in places open to
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CHAPTER 01:
NUCLEAR ACTIVITIES: IONISING RADIATION AND HEALTH AND ENVIRONMENTAL RISKS
ASN report on the state of nuclear safety and radiation protection in France in 2015