Repères - N°48 / March 2021 - The IRSN magazine - 17

EMERGENCY
MEANS AND PROVISIONS
What means are deployed to map a contaminated area?
To protect the population in the event of a nuclear accident with releases, the priority is to quickly and reliably identify
the affected areas requiring protection measures, in order to advise the authorities. IRSN's strategy is based on
the successive deployment of measurement resources in the field, in constant contact with its Emergency Center (CTC)
in Hauts-de-Seine department. Some means have been developed as a result of the Fukushima Daiichi accident.
Aircraft: rough out
the impacted area

5

* 4 gamma detectors
* 40 km x 40 km area,
6-hour overflight of a wide
area around the plant
* Speed 300 kmph,
height 300 m

2

* Sampling (water, grass,
soil, agricultural production,
etc.)
* Analysis in laboratory
vehicles

Helicopter:
identify the relocation
perimeter

!

* 4 gamma detectors
* 10 km x 10 km area
* Speed 150 kmph,
height 50-300 m

3

Staff in the field and
laboratory vehicle:
characterize, from the
ground, the contaminated
zones that are invisible
from the air

* Measurement of ground
contamination levels by
in situ gamma spectrometry

Vehicles:
confirm the relocation
perimeter

4

* In situ gamma spectrometry

Aircraft and helicopter:
identify contaminated
zones from the air

* 4 gamma detectors

* Measures at the edge
of the relocation perimeter
to clear villages

* Overflight of a wide area
following the direction
of releases

* Manual or quad measurements
in inaccessible zones

* Guided by the CTC
according to modeling
D3 D4 D5

D1 D2

The IRSN Emergency Center (CTC) in constant liaison
IRSN's CTC is based in Fontenay-aux-Roses (Hauts-de-Seine
department).
* It provides technical information on the accident
(type of release, approximate quantity, weather conditions, etc.).
* It uses the measurements taken in the field and establishes
a diagnosis of the effective doses in the impacted zone
in the form of a map to refine modeling.
* It provides the authorities with the information required
to protect the population.

Two types of zones impacted by protection measures
By comparing the measurements and the results obtained
from modeling, IRSN defines the zoning.
Relocation perimeter (PE)

The population is informed on a daily basis
The authorities, informed by IRSN, decide on protection measures: sheltering in place, relocation of the population,
dietary restrictions (self-consumption, gathering, hunting, fishing, etc.) and control of products before sale.
End of releases
D0

D1

Relocation perimeter map
D2

D1-D2: establishing
the relocation perimeter
in support of the
prefect's decision.

D3

D4

Dietary restriction zone

Map of the control
and restriction zones
D5
Establishing zones
where control and food
restrictions are in place,
in support of the prefect's
decision.

© Art Presse/ABG Communication/IRSN Media Library/Repères magazine

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Page 17 - Repères No. 48 - March 2021
Repères - N°48 / March 2021 - The IRSN magazine

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