Dear colleagues,
We are seeking a successful candidate for a Ph-D thesis whose subject is
detailed below:
Thesis title: Impact of Boron on the {Cs-X-I-O-H} system through the
transport inside the reactor coolant system (RCS) of a pressurised nuclear
reactor
Abstract
The evaluation of the fission product releases outside in case of a severe
accident occurring to a pressurised nuclear water reactor (PWR) is one of the
missions of the IRSN (French Institute of Radioprotection and Nuclear Safety)
which makes expertise on the nuclear and radiological risks.
Iodine is one of the main fission product (FP) studied due to its radiological
consequences at short term cause by the volatile forms in the event of
inhalation. Speciation and amount of iodine release are still investigated in
order to reduce the remaining uncertainties.
Transport of iodine through the RCS is still misunderstood. Thus, IRSN/DPAM
has launched an international program coupling experiments and modelling
(CHIP - CHimie de lIode dans le circuit Primaire) whose objective is to identify
and characterise the kinetics of reactions occurring in the gaseous phase of
the RCS. To be able to develop a predictive model of reactivity of iodine in
the RCS, which will be integrated in the European computational tool of
reference of simulation of severe accidents, called ASTEC, reaction
mechanisms made up of a whole of elementary reactions must be established
and associated to thermo-kinetic constants. The research work proposed is a
part of this framework.
The results of PHEBUS-FP tests highlighted a strong impact of the nature of
the control rods (governing the reactivity inside the nuclear reactor fuel) on
iodine transport. The control rods made of boron carbide (B4C) are presumed
to promote the formation of volatile iodine via an indirect role by trapping
some specific fission products which are supposed to form refractory iodine
molecules. One of these fission products is Caesium, which forms aerosols of
CsI with iodine; if the caesium borates appear stable under the conditions of
interest that would limit the possibilities of iodine/caesium interactions and
thus could explain the strongest proportion of volatile iodine in PHEBUS-PF
test with control rods in B4C.
The objective of the PhD is to study the gas-phase reactivity between boron
and caesium using computational chemistry tools (ab initio/DFT). The stable
forms of the boron species will be determined and the reactions involving
boron and caesium will be characterized. These reactions will be therefore
implemented in a reaction mechanism. Some severe accident scenarios will be
simulated in order to calculate iodine speciation. The models will be compared
to some experimental results coming from an international programme called
CHIP.
Contacts:
Laurent Cantrel IRSN/DPAM/SEMIC, CE Cadarache, F-13115 Saint Paul lez
Durance, France, email: [log in to unmask], tel: (33)442199450
Florent Louis University of Lille 1, F-59655 Villeneuve d'Ascq, France,
email: [log in to unmask], tel: (33)320336332
The PhD fellowship is funded by the French Institute of Radioprotection and
Nuclear Safety (IRSN, http://www.irsn.fr/) and available for 3 years.
Start October 2010.
Salary of the grant research: 1550 /net per month.
Required Skills: Kinetics, Thermodynamics, Quantum Chemistry
Candidates must apply before May 7th by sending detailed curriculum, letter of
motivation and references to Florent Louis and Laurent Cantrel
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