TY - JOUR
T1 - Chemical reactions of fission product deposits and iodine transport in primary circuit conditions
AU - Kalilainen, Jarmo
AU - Kärkelä, Teemu
AU - Zilliacus, Riitta
AU - Tapper, Unto
AU - Auvinen, Ari
AU - Jokiniemi, Jorma
PY - 2014
Y1 - 2014
N2 - The objective of this work was to examine the chemical
reactions taking place on primary circuit surfaces and
their effect on fission product transport in a severe
nuclear reactor accident. Especially transport of gaseous
and aerosol phase iodine was studied. Caesium iodide
(CsI) was used as precursor material for iodine species.
Also, effects of molybdenum and boron on transport of
iodine were investigated. The experimental work showed
that when CsI alone was used as a precursor, as much as
20% of the released iodine was in gaseous form and the
rest as aerosol particles. Aerosol particles were most
likely CsI. When the amount of hydrogen in the carrier
gas was increased, the fraction of gaseous iodine
decreased. When Boron was added to the precursor, a
glassy caesium borate surface was formed on the crucible.
Boron trapped most of the caesium and also a fraction of
iodine, causing almost all released iodine to be in
gaseous form. When Mo was introduced in the precursor,
most of the iodine was again released in gaseous form.
Oxidised Mo reacted with caesium releasing iodine from
CsI. The effect of Mo on iodine transport depended much
on H 2 concentration and was observed to be substantially
greater on stainless steel surface. When stainless steel
crucible was used, Mo was found in small amounts from
aerosol particles, indicating that it was probably
released as caesium molybdate or as molybdenum oxide
AB - The objective of this work was to examine the chemical
reactions taking place on primary circuit surfaces and
their effect on fission product transport in a severe
nuclear reactor accident. Especially transport of gaseous
and aerosol phase iodine was studied. Caesium iodide
(CsI) was used as precursor material for iodine species.
Also, effects of molybdenum and boron on transport of
iodine were investigated. The experimental work showed
that when CsI alone was used as a precursor, as much as
20% of the released iodine was in gaseous form and the
rest as aerosol particles. Aerosol particles were most
likely CsI. When the amount of hydrogen in the carrier
gas was increased, the fraction of gaseous iodine
decreased. When Boron was added to the precursor, a
glassy caesium borate surface was formed on the crucible.
Boron trapped most of the caesium and also a fraction of
iodine, causing almost all released iodine to be in
gaseous form. When Mo was introduced in the precursor,
most of the iodine was again released in gaseous form.
Oxidised Mo reacted with caesium releasing iodine from
CsI. The effect of Mo on iodine transport depended much
on H 2 concentration and was observed to be substantially
greater on stainless steel surface. When stainless steel
crucible was used, Mo was found in small amounts from
aerosol particles, indicating that it was probably
released as caesium molybdate or as molybdenum oxide
U2 - 10.1016/j.nucengdes.2013.11.078
DO - 10.1016/j.nucengdes.2013.11.078
M3 - Article
VL - 267
SP - 140
EP - 147
JO - Nuclear Engineering and Design
JF - Nuclear Engineering and Design
SN - 0029-5493
ER -