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by Knudsen effusion mass spectrometryNakajima, Kunihisa; Takai, Toshihide; Furukawa, Tomohiro; Osaka, Masahiko
Journal of Nuclear Materials, 491, p.183 - 189, 2017/08
Times Cited Count：8 Percentile：60.93(Materials Science, Multidisciplinary)One of the main chemical forms of cesium in the gas phase during severe accidents of light water reactor is expected to be cesium metaborate, CsBO, by thermodynamic equilibrium calculation considering reaction with boron. But accuracy of the thermodynamic data of gaseous metaborate, CsBO(g), has been judged as poor quality. Thus, Knudsen effusion mass spectrometric measurement of CsBO was carried out to obtain reliable thermodynamic data. The evaluated values of standard enthalpy of formation of CsBO(g), 
H
(CsBO,g), by the 2nd and 3rd law treatments are -700.7
10.7 kJ/mol and -697.010.6 kJ/mol, respectively, and agree with each other within the errors, which suggests our data are reliable. Further, it was found that the existing data of the Gibbs energy function and the standard enthalpy of formation agreed well with the values evaluated in this study, which indicates the existing thermodynamic data are also reliable.
; Konishi, Satoshi; ; Kurasawa, T.; ; Katsuta, Hiroji; ; Naruse, Yuji
JAERI-M 82-194, 47 Pages, 1982/12
no abstracts in English
Takai, Toshihide; Nakajima, Kunihisa; Furukawa, Tomohiro; Osaka, Masahiko
no journal, ,
To develop reliable thermodynamic database of fission products is necessary for more accurate evaluation of fission product release and transport behavior using progression process analysis code under severe accident. This presentation introduces maintenance situation of high temperature mass spectrometer and reliability evaluation result.
Takai, Toshihide; Nakajima, Kunihisa; Furukawa, Tomohiro; Osaka, Masahiko
no journal, ,
Improvement of the serve accident analysis code is important to evaluate the distribution of the released fission products (FPs) in the reactor more precisely from the view point of both the removal preparation of the fuel debris in the Fukushima Daiichi Nuclear Power Station and improved source term evaluation. The development of the calculation model, which can evaluate the effect of atmosphere and the chemical reaction between the released FPs and control rod material (B
C) at elevated temperature, is important for this purpose. The measurement technique of the equilibrium vapor pressure using a high temperature mass spectrometer was under development to expand the thermodynamic database of the simulated FPs, because the chemical equilibrium analysis plays an important role to clarify the effect of chemical reactions. In this study, the apparatus was developed for the equilibrium vapor pressure measurements, and then the reliability of measurement results was evaluated.
by Knudsen effusion mass spectrometryNakajima, Kunihisa; Takai, Toshihide; Furukawa, Tomohiro; Osaka, Masahiko
no journal, ,
Gaseous cesium metaborate, CsBO(g), is predicted to be the main cesium vapor species, depending on temperature, in severe light water reactor accidents according to thermodynamic analysis, which treats chemical reactions between boron and cesium. But quality of the thermodynamic data of CsBO(g) used in this thermodynamic analysis is considered to be poor. Thus, Knudsen-effusion mass-spectrometric measurement of CsBO was performed to obtain reliable thermodynamic quantities of CsBO(g). The standard enthalpy values of formation of CsBO(g), 
(CsBO,g), were obtained by the 2nd law and the 3rd law treatments from measured vapor pressures and found to be -700.6 9.8kJ/mol and -698.0 10.6kJ/mol, respectively. These two values agree within the error limits and the evaluated thermodynamic data of CsBO(g) are considered to be reliable.
