Laurent Cantrel

• Dr.
• Head of Department at Institut de Radioprotection et de Sûreté Nucléaire (IRSN)

In the research field on severe accidents in nuclear power plant, a specific scenario correspond to accident with oxidative conditions for which damaged fuel can be highly oxidised with significant releases of ruthenium oxides. Ruthenium chemistry is complex, and the current knowledge has to be deepened to better assess ruthenium source term with p...

Pool scrubbing has shown potential efficiency to reduce the release of fission products, especially in aerosol forms, into the environment. Considering the large test conditions where pool scrubbing might be encountered, there is still a lack of systematic analysis of this phenomenon, especially its dependence on different hydrodynamic regimes. Exp...

Experimental results are reported on the airborne release, under fire conditions, of hazardous materials dissolved in a mixture of organic solvents [tributylphosphate (TBP) and hydrogenated tetrapropylene (HTP)] representative of the nuclear fuel recycling process. Cerium and ruthenium have been considered, respectively, as stable and volatile fiss...

During a Severe Accident (SA) occurring in a nuclear power plant, many Fission Products (FP) are released from the degraded fuel and are transported in the Reactor Coolant System (RCS). Depending on their volatility, FP can be either deposited on the surface of the Reactor Coolant System (RCS) or transported into the containment building from where...

106Ru is a radioactive isotope usually generated by the nuclear industry within power plant reactors. During a nuclear accident, 106Ru reacts with oxygen, leading to the production of highly volatile ruthenium tetroxide RuO4. The combination of volatility and radioactivity makes 106RuO4, one of the most radiotoxic species and justifies the developm...

The reprocessing of spent nuclear fuel produces high level liquid waste (HLLW). Due to the decay heat, the concentrated nitric solutions containing fission products (FP) are stored in cooled tanks. Actually, the loss-of-cooling accident on these HLLW storage tanks could lead to releases of radioactive materials to the environment, especially ruthen...

A multi-partner program managed and mainly conducted by IRSN (Cadarache & Saclay) with main participations of the LCP-A2MC, LPCT & CEA-Gif-sur-Yvette labs as well as the SOMEZ Co: Capture of radioactove iodine after a (hypothetical) Severe Nuclear Accident. Use of silver-exchanged zeolites to trap the various chemical forms of iodine, especially vo...

As part of study of the volatilization ruthenium behaviour in a boiling nitric solution, this paper presents the results of experiments dealing with the influence of different parameters (Ru and HNO3 concentrations, temperature, water addition) and the effect of in-situ inhibitors to mitigate potential releases. The amount of Ru volatilized from a...

The effect of Silver-Indium-Cadmiun (SIC) control rod on the transport of volatile fission products (I, Cs, Mo) in conditions of a Reactor Coolant System under NPP severe accident was investigated within three semi-integral tests in a thermal gradient tube. The experiments addressed separately the effect of each SIC element. Nature of transported a...

A series of Zr‐based UiO‐n MOF materials (n=66, 67, 68) have been studied for iodine capture. Gaseous iodine adsorption was collected kinetically from a home‐made set‐up allowing the continuous measurement of iodine content trapped within UiO‐n compounds, with organic functionalities (−H, −CH3, −Cl, −Br, −(OH)2, −NO2, −NH2, (−NH2)2, −CH2 NH2) by in...

Ab initio calculations have been carried out to investigate in detail the effect of potential inhibiting species (CO, H 2 O, CH 3 Cl and Cl 2) on the adsorption of iodine species (I 2 and CH 3 I) in silver-exchanged zeolites of different Si/Al ratios and structures (faujasite, mordenite, chabazite and clinoptilolite). We have found that the adsorpt...

Gaseous iodine has been captured by using a series of zirconium‐based UiO‐n metal–organic framework (MOF) sorbents. This study highlights the significant role of amino groups attached to the organic linker, which enhance the iodine uptake capacity, as well as its conversion into anionic iodide I3− species, trapped within UiO‐n cavities. More inform...

Quantitative predictions of the release of volatile radiocontaminants of ruthenium (Ru) in the environment from either nuclear power plants (NPP) or fuel recycling accidents present significant uncertainties while estimated by severe accidents nuclear analysis codes. Observations of Ru from either experimental or modeling works suggest that the mai...

Gaseous iodomethane (CH3I) is naturally emitted into the atmosphere by biological activity in oceans and during severe accidents (SAs) in nuclear power plants. In this latter case, a part of radioactive iodine such as 131I may be released. Improving the knowledge of CH3I transport and reactivity in the atmosphere is important since they are strongl...

Quantitative predictions of the release of volatile radiocontaminants of ruthenium (Ru) in the environment from either nuclear power plants (NPP) or fuel recycling accidents present significant uncertainties while estimated by severe accidents nuclear analysis codes. Observations of Ru from either experimental or modeling works suggest that the mai...

A severe nuclear accident can lead to the release of radiotoxic iodine compounds in either aerosol form (e.g. metal iodides or iodine oxides) or gaseous form (e.g. organic iodide as CH3I or inorganic as I2) species. ¹³¹I is particularly dangerous because of its possible absorption by the human body especially by the thyroid. Gaseous iodine is mainl...

In the present work, we aim to investigate the ability of the zirconium-based MOF-type compound UiO-66-NH2, to immobilize molecular gaseous iodine under conditions analogous to those encountered in an operating Filtered Containment Venting System (FCVS) line. Typically, the UiO-66-NH2 particles were exposed to ¹³¹I (beta and gamma emitters) and sub...

Gaseous iodomethane are naturally emitted in the atmosphere over oceans through the algae and phytoplankton activities. The fate of naturally emitted iodomethane is of great interest because of the oxidizing properties of iodine in the atmosphere and its impact on the catalytic destruction of the ozone layer. Additionally, iodomethane is one of the...

In this work, Ag/X and Ag/Y faujasite zeolites were evaluated as candidate sorbents for the retention of methyl iodide under conditions close to those expected in a severe nuclear accident. Different categories of tests were conducted from laboratory to semi-pilot scales. First, the effects of temperature and water vapour on the CH3I retention/deco...

Iodine compounds that may be released in case of severe nuclear accident will have important radiotoxicity if they are disseminated in air. One of the most important iodine species is CsI that is deposited on the surfaces of the reactor coolant system. However, depending on the conditions, CsI can volatilize or react with oxidants to produce I 2(g)...

The microhydration of iodous acid has been theoretically studied using the ωB97X-D/aug‐cc‐pVTZ level of theory. Two hydration processes have been examined considering the addition of either successive water molecules or water clusters with a number of water molecules from 1 to 4. The singlet potential energy surface exploration revealed: four monoh...

This document provides a comprehensive overview study on the physico-chemical speciation of radioiodine observed in the atmosphere after various emissions related to nuclear activities: nuclear weapon tests, accident and incident releases, and routine discharges. The study covers different types of nuclear facilities including medical isotope produ...

Modeling of plutonium(IV) behavior during an accidental fire in a reprocessing plant was considered using various non-radioactive metallic surrogates. Among those elements, cerium(IV) was supposed to be a suitable candidate due to possible formation of a complex with TPB, but its extractability and stability have not been studied previously under r...

The structures and thermodynamic properties of microhydrates of caesium metaborate (CsBO2) of nuclear safety interest are reported in this work. CsBO2 + n H2O (n = 1−4) molecular complexes were identified on the potential energy surface. The structures were optimized using the ωB97XD DFT method and the aug-cc-pVTZ basis set. Single-point energies w...

This work presents laboratory tests on gaseous RuO4 filtration carried out at IRSN in Cadarache. The objective is to determine if gaseous ruthenium tetroxide can be trapped by metallic filter and sand bed filter, both elements being used in filtered containment venting systems implemented on French pressurized water reactors. The results show no ru...

The ability of Ag-exchanged mordenite (Ag-MOR) to capture iodine species such as I2 and CH3I as released for instance during a nuclear accident can be severely limited by the presence of volatile organic compounds (VOCs) that can disrupt their adsorption in the zeolite. Here, using density functional theory (DFT), we investigate in detail the adsor...

The coupled cluster single-double and perturbative triple (CCSD(T)) approach within highly correlated wave functions has been performed to better understand the thermochemical properties of gaseous cesium borates. Several corrections were added for core-valence correlation and relativistic effects. Structural parameters have been optimized with the...

AgI aerosols may be produced in severe nuclear accident and are typically used to favour the formation of droplet inducing rain. To elucidate their behaviour, we study at the DFT (PBE+D) level β-AgI surface stability and reactivity. The most stable surfaces are the (110), (100) and (120) ones. These three surfaces are non-polar. On the opposite, th...

This work reports for the first time the structures and the thermodynamics of the microhydrates of iodine nitrogen oxides (INOx). Monohydrates and dihydrates were investigated for five different INOx species (INO, INO2, cis‐IONO, trans‐IONO, and IONO2). The structures of the water complexes were characterized at the ωB97XD/aug‐cc‐pVTZ level of theo...

The PASSAM (Passive and Active Systems on Severe Accident source term Mitigation) project was launched in the frame of the 7th framework programme of the European Commission. Coordinated by IRSN, this four year project (2013–2016) involved nine partners from six countries: IRSN, EDF and university of Lorraine (France); CIEMAT and CSIC (Spain); PSI...

Radioactive gaseous ruthenium tetroxide (RuO4) can be released into the environment in the case of a severe nuclear accident. Using periodic dispersion corrected density functional theory calculations, we have investigated for the first time the adsorption behavior of RuO4 into prototypical porous materials: Metal-Organic Framework (MOF) and zeolit...

In this study, we have investigated the iodine retention behavior of silver zeolite sorbents under a variety of conditions. First, a preliminary study was achieved in liquid phase in order to determine: (i) the main kinetic and thermodynamic characteristics pertaining to the adsorption behavior; (ii) the influence of some zeolitic parameters (natur...

During a severe accident in a Nuclear Power Plant, fission products are released from the degraded fuel and might reach the environment by some nuclear containment building leakages.

The potential use of three Metal-Organic Frameworks (MIL-53(Al), MIL-120(Al) and HKUST-1(Cu)) to adsorb iodine species (I2 and ICH3), which can be released during a severe nuclear accident, is investigated using periodic dispersion density functional theory for the first time. Competitive adsorption of iodine in the presence of water molecules is a...

This paper deals with near past, ongoing, and planned R&D works on fission products (FPs) behavior in reactor cooling system (RCS), containment building and in filtered containment venting systems (FCVS) for severe accident (SA) conditions. All the researches are collaborative works; the overall objective is to develop confident models to be implem...

Radioactive iodine species belong to the most dangerous components of nuclear effluents and waste produced by nuclear facilities. In this work we use computer simulations at the periodic DFT level to investigate dissociative adsorption of iodomethane on silver exchanged mordenite, which is among the most effective sorbents of iodine species availab...

In this theoretical work, the stability of α-Cr2O3 surfaces in various oxidizing and reducing environments has been investigated. The electronic structure calculations, the magnetic properties of the bulk and surfaces have been explored within the DFT+U framework. Investigating a large number of possible terminations we show that the oxidation prom...

In this paper, the mechanism of the HOIO2 + OH → products reaction is investigated using quantum chemistry tools. Two pathways are considered: HOIO2 + OH → OIO2 + H2O and HOIO2 + OH → OIO + H2O2. The potential energy surfaces are calculated at the CCSD(T)/CBS(D,T)//B3LYP/aug-cc-pVTZ level of theory. The OH radical was found to attack iodic acid fro...

Using periodic dispersion corrected Density Functional Theory, the adsorption of I2 and ICH3, which may be released during a severe nuclear accident, has been investigated for three divalent (Cu2+, Pb2+ and Hg2+) cation-exchanged mordenite with a Si/Al ratio of 23. However, gas such as H2O, CO, ClCH3, and Cl2 present in the containment atmosphere c...

During the PHEBUS-FP integral severe accidents simulation tests, gaseous iodine was detected in earlier stages of the simulated accident, coming from the experimental circuit modelling a reactor coolant system. One possible explanation is the existence of some kinetic limitations which promote the persistence of gaseous iodine at low temperature. T...

Using periodic dispersion-corrected DFT calculations, the effect of potential inhibiting species (H2O, NO, CO, CH3Cl and Cl2) on the adsorption of iodine species (I2, CH3I) has been investigated over different monovalent (H, Li, Na, K, Rb, Cs, Cu and Ag) cation-exchanged faujasite. We have found out that van der Waals interactions play an important...

Tributyl-phosphate (TBP), a ligand used in the PUREX liquid-liquid separation process of spent nuclear fuel, can form an explosive mixture in contact with nitric acid that might lead to a violent explosive thermal runaway. In the context of safety of a nuclear reprocessing plant facility, it is crucial to predict the stability of TBP at elevated te...

Quantum chemical calculations have been used to study several reactions leading to the formation of mono-(H$_2$MBP), di-(HDBP) and tributyl-phosphate (TBP) in gas and liquid phases. The energies were calculated using local coupled cluster with single and double excitation operators and perturbative treatment of triple excitations [LCCSD(T)], extrap...

This paper reports computations of thermochemical properties (∆fH°298K, S°298K, Cp = f(T)) of HIO2 isomers (HOOI and HOIO) together with the kinetic parameters of the gas phase HOIO + OH reaction. The calculations are performed using CCSD(T) method on structures previously optimized at the B3LYP/aug-cc-pVTZ level of theory. Spin-orbit coupling is c...

An experimental screening of silver-exchanged zeolites towards the trapping of methyl iodide was carried out with the general aim of limiting as much as possible the iodine release in case of severe nuclear accident. For the first time, a systematic study was implemented in order to better understand the effects of some important parameters such as...

In the case of an hypothetical nuclear accident, fission products are release into the environment. Simulation tools are commonly used to predict the radiological consequences on populations. After the Fukushima accident, significant differences have been observed between measured and modeled concentrations for iodine 131. This can be attributed to...

This paper presents the mechanism and the kinetics of the I2O5 (g)+ H2O (g) = 2 HOIO2 (g) reaction. The potential energy surface was explored with the B3LYP and MP2 methods with the aug-cc-pVTZ basis set. The rate constants were computed as a function of temperature (250−750 K) using transition state theory. At the CCSD(T)/CBS level, the rate const...

The structures, energetics, and thermodynamic properties of HIO3 isomers (HOOOI, HOOIO, HOIO2, and HIO3) have been computed using CCSD(T)/CBS theoretical method. The spin orbit corrections (SOC) have also been evaluated for the each iodine-containing molecule. The SOC value decreases as the iodine valence increases within the molecule. The results...

Silver modified zeolites with a mordenite structure can capture volatile iodine compounds (I2 and ICH3) which can be released during a severe nuclear accident. However under these particular conditions, molecules such as CO and H2O present in the containment atmosphere are expected to inhibit the adsorption of iodine compounds. In the present work,...

The mechanism of CH3I adsorption and thermal decomposition by a Ag/Y sorbent with 23 wt% of silver and Si/Al ratio of 2.5 was investigated using two different spectroscopic techniques. On the one hand, DR-UV-Vis spectroscopy was used in order to monitor the evolution of silver species and their transformation to silver iodide AgI clusters during in...

This paper deals with near past, ongoing and planned R&D works on fission products (FPs) behaviour in Reactor Cooling System (RCS), containment building and in Filtered Containment Venting Systems (FCVS) for severe accident (SA) conditions. For the last topic, in link with the Fukushima post-accident management and possible improvement of mitigatio...

To get an insight into the possible reactivity between iodine oxides and CO, a first step was to study the thermochemical properties and kinetic parameters of the reaction between IO and CO using theoretical chemistry tools. All stationary points involved were optimized using the Becke's three-parameter hybrid exchange functional coupled with the L...

In case of a severe accident occurring in a nuclear reactor, surfaces of the reactor coolant system (RCS), made of stainless steel (304L) rich in Cr (>10%) and Ni (8-12%), are oxidised. Fission products (FPs) are released from melt fuel and flow through the RCS. A part of them is deposited onto surfaces either by vapour condensation or by aerosol d...

Literature thermodynamic data of ruthenium oxyhydroxides reveal large uncertainties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. Reaction energies leading to the formation of all possible oxyhydroxide species RuOx(OH)y(H2O)z h...

Thermodynamics and kinetics of cesium species reactions have been studied by using high-level quantum chemical tools. A systematic theoretical study has been done to find suitable methodology for calculation of reliable thermodynamic properties allowing us to determine bimolecular rate constants with appropriate kinetic theories of gas-phase reacti...

The review of thermodynamic data of ruthenium oxides reveals large uncertain- ties in some of the standard enthalpies of formation, motivating the use of high-level relativistic correlated quantum chemical methods to reduce the level of discrepancies. The reaction energies leading to the formation of ruthenium oxides RuO, RuO2, RuO3, and RuO4 have...

Severe accident (SA) phenomenology related to iodine release to the environment has been closely investigated at IRSN over the last decades, by conducting semi-integral or analytical experimental programs like PHEBUS FP, ISTP (CHIP, EPICUR) and OECD/STEM and contributing to others such as OECD/BIP and THAI. These programs have led to the improvemen...

Severe accident (SA) phenomenology related to iodine release to the environment has been closely investigated at IRSN over the last decades, by conducting semi-integral or analytical experimental programs like PHEBUS FP, ISTP (CHIP, EPICUR) and OECD/STEM and contributing to others such as OECD/BIP and THAI. These programs have led to the improvemen...

Within the past decade, international experimental programs were performed in the area of iodine behaviour in the Reactor Coolant system (RCS) and containment during a severe accident (SA) in a Nuclear Power Plant (NPP). The objectives were to better understand involved physico-chemical processes and develop relevant models in SA codes like ASTEC w...

The STEM (Source Term Evaluation and Mitigation) OECD project operated by IRSN, has been launched mid-2011 in order to improve, in the event of a severe accident (SA) on a nuclear power plant, the evaluation of Source Term (ST) and to reduce uncertainties on specific phenomena dealing with the chemistry of two major fission products: iodine and rut...

We present a relativistic quantum chemical study to determine the best surro- gate for plutonium(IV) to be used in experimental investigations of the behavior of plutonium-nitrate-TBP in fire conditions that might occur in the nuclear fuel refining process known as PUREX. In this study geometries and stabilities of Pu(NO3)6(2-) and Pu(NO3)4(TBP)2 c...

By quantum chemistry calculations, we have evaluated the standard enthalpies of formation of some gaseous species of the Be-O-H chemical system: BeH, BeH2, BeOH, Be(OH)(2) for which the values in the referenced thermodynamic databases (NIST-JANAF [1] or COACH [21) were, due to the lack of experimental data, estimated or reported with a large uncert...

Ruthenium species, volatilized from damaged fuel during a severe accident in a nuclear power plant, are radiotoxic and can be transported to the containment atmosphere in gaseous form. To limit the possible source term to the environment, it is of interest to understand the behaviour of Ru after it has been released from fuel and the phenomena taki...

One main goal of the severe accident integral code ASTEC V2, jointly developed since almost more than 15 years by IRSN and GRS, is to simulate the overall behaviour of fission products (FP) in a damaged nuclear facility. ASTEC applications are source term determinations, level 2 Probabilistic Safety Assessment (PSA2) studies including the determina...

The severe accident integral code ASTEC, jointly developed since almost 20 years by IRSN and GRS, simulates the behaviour of a whole nuclear power plant under severe accident conditions, including severe accident management by engineering systems and procedures. Since 2004, the ASTEC code is progressively becoming the reference European severe acci...

Structure and thermodynamic properties (standard enthalpies of formation and Gibbs free energies) of hydrated caesium species of nuclear safety interest, Cs, CsOH, CsI and its dimer Cs2I2, with one up to three water molecules, are calculated to assess their possible existence in severe accident occurring to a pressurized water reactor. The calculat...

Monohydrated complexes of iodine species (I, I2, HI, and HOI) have been studied by correlated ab initio calculations. The standard enthalpies of formation, Gibbs free energy and the temperature dependence of the heat capacities at constant pressure were calculated. The values obtained have been implemented in ASTEC nuclear accident simulation softw...

We present a systematic study of the thermochemistry for a set of iodine species relevant to atmospheric chemistry. The reactions include H, O and I atoms and H2, OH, HI, I2, iodine monoxide, hypoiodous acid (HOI) and H2O species. The calculations presented were performed using completely renormalized coupled cluster theory including single, double...

Analysis of the results of the Phébus experimental program identified phenomena related to fission product behaviour that are insufficiently described by available empirical models. The combining experimental and theoretical strategy implemented by IRSN to develop models that are able to predict any pressurised water reactor (PWR) severe accident t...

In the case of a hypothetical severe accident in a nuclear power plant, iodine is one of the fission products of major importance. It may be present in various gas-eous forms that could be released to the environment, impacting population health. In such a case, the amount released (the so-called "source term") has to be esti-mated in order to help...

Several accidental scenarios have been simulated using the ASTEC integral IRSN-GRS code for a French 1300 MWe PWR, including several break sizes or locations, highlighting the effect of safety systems and of iodine chemistry in the reactor coolant system (RCS) and in the containment on iodine source term evaluations. Iodine chemistry in the RCS and...

Ab initio electronic structure calculations at the coupled cluster level with a correction for the triples extrapolated to the complete basis set limit have been made for the estimation of the thermochemical properties of Cs2, CsH, CsO, Cs2O, CsX, and Cs2X2 (X = OH, Cl, Br, and I). The standard enthalpies of formation and standard molar entropies a...

The rate constants of the reactions of HOI molecules with H, OH, O ((3)P), and I ((2)P(3/2)) atoms have been estimated over the temperature range 300-2500 K using four different levels of theory. Geometry optimizations and vibrational frequency calculations are performed using MP2 methods combined with two basis sets (cc-pVTZ and 6-311G(d,p)). Sing...

Summary The 5th FWP EURSAFE project highlighted iodine chemistry in the containment as one of the issues requiring further research in order to reduce source term uncertainties. Consequently, a series of studies was launched in the 6th FWP SARNET project aimed at improving the predictability of iodine behaviour during severe accidents via a better...

The rate constants of the reactions of iodine atoms with H(2), H(2)O, HI, and OH have been estimated using 39, 21, 13, and 39 different levels of theory, respectively, and have been compared to the available literature values over the temperature range of 250-2500 K. The aim of this methodological work is to demonstrate that standard theoretical me...

The ASTEC code, jointly developed since several years by IRSN and GRS, is progressively becoming the reference European severe accident integral code through in particular the intensification of research activities carried out since 2004 in the frame of the SARNET European Network of Excellence. The first version of the new series ASTEC V2 has been...

In the case of a hypothetical severe accident in a nuclear power plant, iodine is one of the fission products of major importance. It may be present in various gaseous forms that could be released to the environment, impacting population health. In such a case, the amount released (the so-called “source term”) has to be estimated in order to help t...

The overall aim of the SARNET (Severe Accident Research NETwork), in the EU 6th Framework programme was to integrate in a sustainable manner the research capabilities of fifty-one European organisations from eighteen member states of the European Union (EU) plus the Joint Research Centres, with one Canadian company, to resolve important remaining u...