Influence of chemical speciation in reactor cooling system on pH of suppression pool during BWR severe accident. Issue 4 (3rd April 2018)

• Record Type: Journal Article
• Authors: Shiotsu, Hiroyuki; Ishikawa, Jun; Sugiyama, Tomoyuki; Maruyama, Yu
• Is Part Of: Journal of nuclear science and technology. Volume 55:Issue 4(2018)
• Page Start: 363
• Page End: 373
• Publication Date: 2018-04-03
• Subjects: Severe accident -- fission products -- chemical speciation -- reactor cooling system -- suppression pool -- pH; Nuclear engineering -- Periodicals; Nuclear physics -- Periodicals; Nuclear energy -- Periodicals; 621.4805
• DOI: 10.1080/00223131.2017.1403381
• Languages: English
• ISSNs: 0022-3131

Abstract

ABSTRACT: The influences of chemical speciation for Cs–I–Te–Mo–Sn–B–C–O–H system, simulating a state in the reactor cooling system (RCS) of BWR, on pH of the suppression chamber (S/C) water pool were analytically investigated with PHREEQC code. Major conditions were chosen on the basis of the outputs from a BWR severe accident analysis by THALES2 code and chemical thermodynamic analysis with VICTORIA2.0 code. The chemical thermodynamic analysis showed that the chemical speciation of important volatile FPs, Cs and I was strongly influenced by Mo and B4 C control material. As a consequence, pH of the S/C water pool was predicted to range from approximately 6 to 10, depending on the fraction of volatile FPs transported from the RCS to the S/C water pool and the H2 /H2 O ratio associated with the oxygen potential. It was implied that the formation of volatile I species such as I2 in the S/C water pool was larger by three orders at the lowest pH than that at the highest pH.