The tests on fission product (FP) behavior in piping under severe accidents
are being conducted in the wide range piping integrity demonstration (WIND
) project at JAERI to investigate the piping integrity which may be threate
ned by decay heat from deposited FPs. In order to obtain the background inf
ormation for future WIND experiment and to confirm analytical capabilities
of the FP aerosol analysis codes, ART and VICTORIA, the FP behavior in safe
ty relief valve (SRV) line of BWR during TQUX sequence was analyzed. The an
alyses showed that the mechanisms that control the FP deposition and transp
ort agreed well between the two codes. However, the differences in models s
uch as diffusiophoresis or turbulence, the treatment of chemical forms and
aerosol mass distribution could affect the deposition in piping and, conseq
uently, on the source terms. The WIND experimental analyses were also condu
cted with a three-dimensional fluiddynamic WINDFLOW, ART and an interface m
odule to appropriately couple the fluiddynamics and FP behavior analyses. T
he analyses showed that the major deposition mechanism for cesium iodide (C
sI) is thermophoresis which depends on the thermal gradient in gas. Accordi
ngly, the coupling analyses were found to be essential to accurately predic
t the CsI deposition in piping, to which little attention has been paid in
the previous studies. (C) 2000 Elsevier Science S.A. All rights reserved.