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Pool scrubbing models for iodine components

Abstract

Pool scrubbing is an important mechanism to retain radioactive fission products from being carried into the containment atmosphere or into the secondary piping system. A number of models and computer codes has been developed to predict the retention of aerosols and fission product vapours that are released from the core and injected into water pools of BWR and PWR type reactors during severe accidents. Important codes in this field are BUSCA, SPARC and SUPRA. The present paper summarizes the models for scrubbing of gaseous Iodine components in these codes, discusses the experimental validation, and gives an assessment of the state of knowledge reached and the open questions which persist. The retention of gaseous Iodine components is modelled by the various codes in a very heterogeneous manner. Differences show up in the chemical species considered, the treatment of mass transfer boundary layers on the gaseous and liquid sides, the gas-liquid interface geometry, calculation of equilibrium concentrations and numerical procedures. Especially important is the determination of the pool water pH value. This value is affected by basic aerosols deposited in the water, e.g. Cesium and Rubidium compounds. A consistent model requires a mass balance of these compounds in the pool, thus effectively  More>>
Authors:
Fischer, K [1] 
  1. Battelle Ingenieurtechnik GmbH, Eschborn (Germany)
Publication Date:
Dec 01, 1996
Product Type:
Technical Report
Report Number:
PSI-97-02; CONF-9606320-; NEA/CSNI/R(96)-6.
Reference Number:
SCA: 210100; 210200; PA: AIX-28:037522; EDB-97:078471; SN: 97001796000
Resource Relation:
Conference: 4. CSNI workshop on the chemistry of iodine in reactor safety, Wuerenlingen (Switzerland), 10-12 Jun 1996; Other Information: PBD: Dec 1996; Related Information: Is Part Of Proceedings of the 4. CSNI workshop on the chemistry of iodine in reactor safety; Guentay, S. [ed.] [Paul Scherrer Inst. (PSI), Villigen (Switzerland)]; PB: 716 p.
Subject:
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS; FISSION PRODUCTS; SCRUBBING; COMPUTERIZED SIMULATION; B CODES; CESIUM COMPOUNDS; IODINE; METHYL IODIDE; PH VALUE; RUBIDIUM COMPOUNDS; S CODES; THEORETICAL DATA; VALIDATION; WATER
OSTI ID:
481719
Research Organizations:
Paul Scherrer Inst. (PSI), Villigen (Switzerland)
Country of Origin:
Switzerland
Language:
English
Other Identifying Numbers:
Other: ON: DE97624048; TRN: CH9700226037522
Availability:
INIS; OSTI as DE97624048
Submitting Site:
CHN
Size:
pp. 655-664
Announcement Date:
Jun 23, 1997

Citation Formats

Fischer, K. Pool scrubbing models for iodine components. Switzerland: N. p., 1996. Web.
Fischer, K. Pool scrubbing models for iodine components. Switzerland.
Fischer, K. 1996. "Pool scrubbing models for iodine components." Switzerland.
@misc{etde_481719,
title = {Pool scrubbing models for iodine components}
author = {Fischer, K}
abstractNote = {Pool scrubbing is an important mechanism to retain radioactive fission products from being carried into the containment atmosphere or into the secondary piping system. A number of models and computer codes has been developed to predict the retention of aerosols and fission product vapours that are released from the core and injected into water pools of BWR and PWR type reactors during severe accidents. Important codes in this field are BUSCA, SPARC and SUPRA. The present paper summarizes the models for scrubbing of gaseous Iodine components in these codes, discusses the experimental validation, and gives an assessment of the state of knowledge reached and the open questions which persist. The retention of gaseous Iodine components is modelled by the various codes in a very heterogeneous manner. Differences show up in the chemical species considered, the treatment of mass transfer boundary layers on the gaseous and liquid sides, the gas-liquid interface geometry, calculation of equilibrium concentrations and numerical procedures. Especially important is the determination of the pool water pH value. This value is affected by basic aerosols deposited in the water, e.g. Cesium and Rubidium compounds. A consistent model requires a mass balance of these compounds in the pool, thus effectively coupling the pool scrubbing phenomena of aerosols and gaseous Iodine species. Since the water pool conditions are also affected by drainage flow of condensate water from different regions in the containment, and desorption of dissolved gases on the pool surface is determined by the gas concentrations above the pool, some basic limitations of specialized pool scrubbing codes are given. The paper draws conclusions about the necessity of coupling between containment thermal-hydraulics and pool scrubbing models, and proposes ways of further simulation model development in order to improve source term predictions. (author) 2 tabs., refs.}
place = {Switzerland}
year = {1996}
month = {Dec}
}