Repères - N°48 / March 2021 - The IRSN magazine - 13

SAFETY
Research

Innovative materials
Research was launched after the Fukushima Daiichi accident in order to better protect
the population. Case in point with two programs, MIRE, focused on limiting radioactive
releases, and PreADES, which studies the recovery of fuel debris to prepare for
dismantling in Japan.

Iodine filtering in containment
venting lines

To improve filtration system efficiency in
case of containment venting, research is
focusing on innovative materials. " Zeolites
[minerals mainly composed of aluminum
and silica] enriched with silver very significantly improve the trapping of volatile
iodine, with good resistance to heat and
radiation, " said Laurent Cantrel, Project
Lead. He goes on to say, " We are working
on the aging of these materials and their
performance in severe accident conditions.
Our recommendations could be used as
input by EDF, whose role is to decide which

en years after the accident, knowledge
and safety are improving through
numerous research projects undertaken in France and internationally. By
bringing to light how vulnerable facilities
are to extreme natural hazards, the 2011
accident led to a review of priorities and
stimulated preliminary safety research.
It is essential that radioactive releases in
the form of aerosols or gases be limited
during a core meltdown in the event of an
accident. Characterizing the chemical
species released is also important because
their impact on humans and the environment differs according to their physico-chemical form. These objectives are at
the heart of the MIRE1 collaborative project, led by IRSN.

The PERSEE facility is devoted to studying iodine traps in nuclear facilities.

solution to deploy to mitigate iodine releases. "
Scientists began by deepening their knowledge of the nature of iodine releases with
IRSN's CHROMIA 2 platform. Then, they
compared the trapping capacities of
the existing filtration systems on another
facility, PERSEE 3. Two zeolites were
selected for the final studies. When modified, these porous materials can increase
their chemical affinities with gaseous
iodine to selectively trap it. The addition
of silver proved most effective.

Debris analysis

The purpose of the OECD PreADES 4
project is " to prepare for dismantling
Fukushima Daiichi. The Japanese asked us to
inventory the debris formed by the accident
and their properties, explained Marc
Barrachin, specialist in severe accidents.
IRSN provided its knowledge on core meltdown accidents, " acquired
through the Phébus PF 5
program, based on five
small-scale core meltdown
tests carried out under the
program, " he continued.
Lessons were learned on
Understanding
the degradation of the
and modeling
core and fission product
the accident
behavior. Debris analysis
campaigns were conirsn.fr/R48-EN

WEBMAGAZINE

READ

ducted. PreADES focuses on the boiling
water reactors involved in the accident in
Japan which " are made of the same materials, but in different proportions. We think
we will find more metal in Fukushima
Daiichi debris, " Barrachin concludes.
Examining the debris will provide useful
information to design the robots intended
to recover it and the protection needed to
evacuate it.
Analysis of the composition of the corium
collected, resulting from the core meltdown, will provide information on what
happened in March 2011.
With this information and the ASTEC
software developed for the simulation of
a reactor core meltdown, it will be possible
to gain a better understanding of what
happened in the accident (see Webmag). n
1. Mitigation of releases to the environment
in the event of a nuclear accident,
with the participation of EDF.
2. Experimental platform for fission product
chemistry and radiochemistry.
3. Experimental research platform on purification
of radioactive effluents.
4. Preparatory Study on Analysis of Fuel Debris,
project under the auspices of the OECD,
started in 2017.
5. International project (1998-2010)
irsn.fr/phebusEN
Find out more:

MIRE project irsn.fr/Mire-EN
PreADES program irsn.fr/news-20180522

Page 13 - Repères No. 48 - March 2021

https://www.irsn.fr/phebusEN http://www.irsn.fr/phebus https://www.irsn.fr/R48-EN https://www.irsn.fr/Mire-EN http://irsn.fr/Projet-Mire https://www.irsn.fr/news-20180522 https://www.irsn.fr/news-20180522

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

Table of Contents for the Digital Edition of Repères - N°48 / March 2021 - The IRSN magazine