Abstract
In case of a severe accident in a nuclear reactor, radioactive iodine may be released into the environment, impacting significantly on the source term. Determination of the amount released, and of the physical state of iodine (gaseous or solid aerosol form), is thus a major issue, regarding the improvement of the accident management and mitigation measures An experimental study has been launched at VTT to investigate the behaviour of iodine containing deposits on primary circuit surfaces during a severe nuclear accident. Caesium iodide was used as a precursor material in order to study the effects of carrier gas composition (varying H2/H2O molar ratio) on the release of gaseous iodine from the precursor. A special interest was on the behaviour under presence of air, and the effect of CsI mixed with boron and/or caesium hydroxide was also examined At first, the influence of boron on the caesium iodide behaviour at 650°C under three atmospheres: Ar/H2O, Ar/H2O/H2 and Ar/Air was investigated. The experiments showed that the transport of gaseous iodine is enhanced by the presence of boron, because of the formation of a glassy caesium borate compound in the crucible, suggesting that a reaction between condensed caesium iodide and boron is possible on the surface of primary circuit in these conditions. The amount of steam present in the carrier gas, more than air, seems to have an influence on the caesium borate formation Secondly, experiments were performed with a precursor mixture of CsI, CsOH and B2O3. The aim was to have an initial Cs/I molar ratio higher than one, which is more representative to the conditions in case of the severe nuclear accident. Preliminary results have shown that the amount of gaseous iodine is higher than the iodine containing particles. Presence of boron still tends to favour the formation of gaseous iodine.
| Original language | English |
|---|---|
| Title of host publication | International Congress on Advances in Nuclear Power Plants, ICAPP 2016 |
| Publisher | American Nuclear Society ANS |
| Pages | 752-758 |
| Number of pages | 7 |
| Volume | 1 |
| ISBN (Electronic) | 9781510825949 |
| Publication status | Published - 1 Jan 2016 |
| MoE publication type | A4 Article in a conference publication |
| Event | International Congress on Advances in Nuclear Power Plants, ICAPP 2016 - Hyatt Regency San Francisco, San Francisco, United States Duration: 17 Apr 2016 → 20 Apr 2016 |
Conference
| Conference | International Congress on Advances in Nuclear Power Plants, ICAPP 2016 |
|---|---|
| Abbreviated title | ICAPP 2016 |
| Country | United States |
| City | San Francisco |
| Period | 17/04/16 → 20/04/16 |
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Experimental study of the boron and air effects on iodine transport in the primary circuit during a severe nuclear accident. / Gouëllo, Mélany; Hokkinen, Jouni; Kärkelä, Teemu; Auvinen, Ari.
International Congress on Advances in Nuclear Power Plants, ICAPP 2016. Vol. 1 American Nuclear Society ANS, 2016. p. 752-758.Research output: Chapter in Book/Report/Conference proceeding › Conference article in proceedings › Scientific › peer-review
TY - GEN
T1 - Experimental study of the boron and air effects on iodine transport in the primary circuit during a severe nuclear accident
AU - Gouëllo, Mélany
AU - Hokkinen, Jouni
AU - Kärkelä, Teemu
AU - Auvinen, Ari
PY - 2016/1/1
Y1 - 2016/1/1
N2 - In case of a severe accident in a nuclear reactor, radioactive iodine may be released into the environment, impacting significantly on the source term. Determination of the amount released, and of the physical state of iodine (gaseous or solid aerosol form), is thus a major issue, regarding the improvement of the accident management and mitigation measures An experimental study has been launched at VTT to investigate the behaviour of iodine containing deposits on primary circuit surfaces during a severe nuclear accident. Caesium iodide was used as a precursor material in order to study the effects of carrier gas composition (varying H2/H2O molar ratio) on the release of gaseous iodine from the precursor. A special interest was on the behaviour under presence of air, and the effect of CsI mixed with boron and/or caesium hydroxide was also examined At first, the influence of boron on the caesium iodide behaviour at 650°C under three atmospheres: Ar/H2O, Ar/H2O/H2 and Ar/Air was investigated. The experiments showed that the transport of gaseous iodine is enhanced by the presence of boron, because of the formation of a glassy caesium borate compound in the crucible, suggesting that a reaction between condensed caesium iodide and boron is possible on the surface of primary circuit in these conditions. The amount of steam present in the carrier gas, more than air, seems to have an influence on the caesium borate formation Secondly, experiments were performed with a precursor mixture of CsI, CsOH and B2O3. The aim was to have an initial Cs/I molar ratio higher than one, which is more representative to the conditions in case of the severe nuclear accident. Preliminary results have shown that the amount of gaseous iodine is higher than the iodine containing particles. Presence of boron still tends to favour the formation of gaseous iodine.
AB - In case of a severe accident in a nuclear reactor, radioactive iodine may be released into the environment, impacting significantly on the source term. Determination of the amount released, and of the physical state of iodine (gaseous or solid aerosol form), is thus a major issue, regarding the improvement of the accident management and mitigation measures An experimental study has been launched at VTT to investigate the behaviour of iodine containing deposits on primary circuit surfaces during a severe nuclear accident. Caesium iodide was used as a precursor material in order to study the effects of carrier gas composition (varying H2/H2O molar ratio) on the release of gaseous iodine from the precursor. A special interest was on the behaviour under presence of air, and the effect of CsI mixed with boron and/or caesium hydroxide was also examined At first, the influence of boron on the caesium iodide behaviour at 650°C under three atmospheres: Ar/H2O, Ar/H2O/H2 and Ar/Air was investigated. The experiments showed that the transport of gaseous iodine is enhanced by the presence of boron, because of the formation of a glassy caesium borate compound in the crucible, suggesting that a reaction between condensed caesium iodide and boron is possible on the surface of primary circuit in these conditions. The amount of steam present in the carrier gas, more than air, seems to have an influence on the caesium borate formation Secondly, experiments were performed with a precursor mixture of CsI, CsOH and B2O3. The aim was to have an initial Cs/I molar ratio higher than one, which is more representative to the conditions in case of the severe nuclear accident. Preliminary results have shown that the amount of gaseous iodine is higher than the iodine containing particles. Presence of boron still tends to favour the formation of gaseous iodine.
UR - http://www.scopus.com/inward/record.url?scp=84986191395&partnerID=8YFLogxK
M3 - Conference article in proceedings
VL - 1
SP - 752
EP - 758
BT - International Congress on Advances in Nuclear Power Plants, ICAPP 2016
PB - American Nuclear Society ANS
ER -