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Ionising radiationmay be of natural
origin or caused by human activities,
referred to as nuclear activities.
The exposure of the population
to naturally occurring ionising
radiation is the result of the presence
of radionuclides of terrestrial
origin in the environment, radon
emanations from the ground and
exposure to cosmic radiation.
Nuclear activities are activities
entailing a risk of exposure to
ionising radiation, emanating either
from an artificial source or from
natural radionuclides. These nuclear
activities include those conducted
in Basic Nuclear Installations (BNIs)
and the transport of radioactive
substances, as well as in all medical,
veterinary, industrial and research
facilities where ionising radiation
is used.
Ionising radiation is defined as
radiation that is capable of producing
ions – directly or indirectly – when
it passes throughmatter. It includes
X-rays, alpha, beta and gamma
rays, and neutron radiation, all of
which have different energies and
penetration powers.
The effects of ionising radiation on
living beings can be “deterministic”
(health effects such as erythema,
radiodermatitis, radionecrosis
and cataracts, which are certain to
appear when the dose of radiation
received exceeds a certain threshold)
or “probabilistic” (probability
of occurrence of cancers in an
individual, but no certainty).
The protective measures against
ionising radiation aim to avoid
deterministic effects, but also to
reduce the probability of occurrence
of radiation-induced cancers, which
constitute the main risk.
Understanding the risks linked
to ionising radiation is based on
healthmonitoring (cancer registers),
epidemiological investigation and
risk assessment via extrapolation to
low doses of the risks observed at
high doses. There are still however
numerous uncertainties and
unknowns, in particular with regard
to radio-sensitivity, the effects of low
doses, the radiological signature of
cancers and certain non-cancerous
diseases.
Exposure to ionising
radiation in france
The entire French population is
potentially exposed to ionising
radiation, but to differing degrees,
depending on whether the ionising
radiation is of natural origin or the
result of human activities.
On average, the exposure of an
individual in France was estimated
by the French Institute for Radiation
Protection andNuclear Safety (IRSN)
at 4.5millisieverts (mSv) per year in
2010, varying by a factor of up to 5
depending on the location.
The sources of this exposure are as
follows:
•
for about 1 mSv/year, naturally
occurring radioactivity excluding
radon, including 0.6 mSv/year
for radiation of telluric origin,
0.3mSv/year for cosmic radiation
and 0.6 mSv/year for internal
exposure from food;
•
for about 1.4mSv/year, radon, with
considerable variation related to
the geological characteristics of the
land (a newmap of the country was
produced in 2011 according to the
radon exhalation potential) and to
the buildings themselves; in zones
defined as high-priority, periodic
measurements must be taken in
places open to the public and in
the workplace. A national action
plan for the period 2011-2015 has
been implemented; its results and
a new plan for the period 2016-
2019 will be published in 2016;
•
for about 1.6 mSv/year (estimate
for 2015), diagnostic radiological
examinations, with a clear upwards
trend (+ 23% from2007 to 2012);
particular attention must thus
be paid to controlling the doses
delivered to the patients;
•
for about 0.02mSv/year, the other
artificial sources of exposure: past
airborne nuclear tests, accidents
affecting facilities, releases from
nuclear installations.
Nuclear activity workers undergo
specific monitoring (more than
350,000 individuals in 2014); in
2014, the annual dose remained
below 1 mSv (annual effective
dose limit for the public) for 96%
of the workforce monitored, while
20mSv (regulation limit for nuclear
workers) was exceeded for eight
individuals, as was the case in 2013;
the collective dose has fallen by about
50% since 1996while the population
monitored has grown by about 50%.
For workers in activity sectors
entailing technological enhancement
of naturally occurring radioactive
materials, the doses received in 85%
of cases are less than 1 mSv/year.
In a number of known industrial
sectors however, it is quite probable
that this value will be occasionally
exceeded.
Finally, aircrews are subject to
particularly close monitoring owing
Nuclear activities:
ionising radiation and health
and environmental risks
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ASN Report on the state of nuclear safety and radiation protection in France in 2015
SIGNIFICANT EVENTS IN 2015