Release of radioactive materials from a degrading core (RADECO): RADECO summary report

Riitta Zilliacus, Tommi Kekki, Ilona Lindholm, Atso Suopajärvi

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

Abstract

The formation of organic iodine on painted surface in water and in N2 was studied with and without radiation. The water pH in the experiment was 9.3 or 7. In neutral solution small amount of volatile organic iodide was detected. In high pH all volatile iodine was very small amount of inorganic iodine. Experiments performed in gas phase show some formation of volatile compounds, but most of these were rapidly adsorbed on other surfaces and only a negligible amount of organic iodine was detected. The severe accidents during shutdown conditions were examined with MELCOR code. Olkiluoto 1 was selected for the reference plant. Two accident scenarios starting during shutdown conditions with pressure vessel upper head opened were studied: a station blackout with initially intact pressure vessel (RPV) and a LOCA starting with a break in the bottom head of the RPV. The results of the calculation suggest that even a small hole in the RPV Bottom Head may allow some air ingress to the core region. If the Lower Head is intact no air ingress to the RPV would take place. Station blackout scenario resulted in high zirconium oxidation fraction, about 60%. The oxidation fraction in the Bottom Head LOCA case was 14%. In the calculated cases Ru release from the core equaled to 8-23% of the initial core inventory. The highest Ru release was obtained in the station blackout scenario.
Original languageEnglish
Title of host publicationSAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010
Subtitle of host publicationInterim Report
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Pages261-275
ISBN (Electronic)978-951-38-7267-0
ISBN (Print)978-951-38-7266-3
Publication statusPublished - 2009
MoE publication typeNot Eligible

Publication series

SeriesVTT Tiedotteita - Research Notes
Number2466
ISSN1235-0605

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iodine
accident
vessel
oxidation
air
iodide
experiment
water
material
gas
station

Cite this

Zilliacus, R., Kekki, T., Lindholm, I., & Suopajärvi, A. (2009). Release of radioactive materials from a degrading core (RADECO): RADECO summary report. In SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010 : Interim Report (pp. 261-275). Espoo: VTT Technical Research Centre of Finland. VTT Tiedotteita - Research Notes, No. 2466
Zilliacus, Riitta ; Kekki, Tommi ; Lindholm, Ilona ; Suopajärvi, Atso. / Release of radioactive materials from a degrading core (RADECO) : RADECO summary report. SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010 : Interim Report. Espoo : VTT Technical Research Centre of Finland, 2009. pp. 261-275 (VTT Tiedotteita - Research Notes; No. 2466).
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abstract = "The formation of organic iodine on painted surface in water and in N2 was studied with and without radiation. The water pH in the experiment was 9.3 or 7. In neutral solution small amount of volatile organic iodide was detected. In high pH all volatile iodine was very small amount of inorganic iodine. Experiments performed in gas phase show some formation of volatile compounds, but most of these were rapidly adsorbed on other surfaces and only a negligible amount of organic iodine was detected. The severe accidents during shutdown conditions were examined with MELCOR code. Olkiluoto 1 was selected for the reference plant. Two accident scenarios starting during shutdown conditions with pressure vessel upper head opened were studied: a station blackout with initially intact pressure vessel (RPV) and a LOCA starting with a break in the bottom head of the RPV. The results of the calculation suggest that even a small hole in the RPV Bottom Head may allow some air ingress to the core region. If the Lower Head is intact no air ingress to the RPV would take place. Station blackout scenario resulted in high zirconium oxidation fraction, about 60{\%}. The oxidation fraction in the Bottom Head LOCA case was 14{\%}. In the calculated cases Ru release from the core equaled to 8-23{\%} of the initial core inventory. The highest Ru release was obtained in the station blackout scenario.",
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Zilliacus, R, Kekki, T, Lindholm, I & Suopajärvi, A 2009, Release of radioactive materials from a degrading core (RADECO): RADECO summary report. in SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010 : Interim Report. VTT Technical Research Centre of Finland, Espoo, VTT Tiedotteita - Research Notes, no. 2466, pp. 261-275.

Release of radioactive materials from a degrading core (RADECO) : RADECO summary report. / Zilliacus, Riitta; Kekki, Tommi; Lindholm, Ilona; Suopajärvi, Atso.

SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010 : Interim Report. Espoo : VTT Technical Research Centre of Finland, 2009. p. 261-275 (VTT Tiedotteita - Research Notes; No. 2466).

Research output: Chapter in Book/Report/Conference proceedingChapter or book articleProfessional

TY - CHAP

T1 - Release of radioactive materials from a degrading core (RADECO)

T2 - RADECO summary report

AU - Zilliacus, Riitta

AU - Kekki, Tommi

AU - Lindholm, Ilona

AU - Suopajärvi, Atso

PY - 2009

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N2 - The formation of organic iodine on painted surface in water and in N2 was studied with and without radiation. The water pH in the experiment was 9.3 or 7. In neutral solution small amount of volatile organic iodide was detected. In high pH all volatile iodine was very small amount of inorganic iodine. Experiments performed in gas phase show some formation of volatile compounds, but most of these were rapidly adsorbed on other surfaces and only a negligible amount of organic iodine was detected. The severe accidents during shutdown conditions were examined with MELCOR code. Olkiluoto 1 was selected for the reference plant. Two accident scenarios starting during shutdown conditions with pressure vessel upper head opened were studied: a station blackout with initially intact pressure vessel (RPV) and a LOCA starting with a break in the bottom head of the RPV. The results of the calculation suggest that even a small hole in the RPV Bottom Head may allow some air ingress to the core region. If the Lower Head is intact no air ingress to the RPV would take place. Station blackout scenario resulted in high zirconium oxidation fraction, about 60%. The oxidation fraction in the Bottom Head LOCA case was 14%. In the calculated cases Ru release from the core equaled to 8-23% of the initial core inventory. The highest Ru release was obtained in the station blackout scenario.

AB - The formation of organic iodine on painted surface in water and in N2 was studied with and without radiation. The water pH in the experiment was 9.3 or 7. In neutral solution small amount of volatile organic iodide was detected. In high pH all volatile iodine was very small amount of inorganic iodine. Experiments performed in gas phase show some formation of volatile compounds, but most of these were rapidly adsorbed on other surfaces and only a negligible amount of organic iodine was detected. The severe accidents during shutdown conditions were examined with MELCOR code. Olkiluoto 1 was selected for the reference plant. Two accident scenarios starting during shutdown conditions with pressure vessel upper head opened were studied: a station blackout with initially intact pressure vessel (RPV) and a LOCA starting with a break in the bottom head of the RPV. The results of the calculation suggest that even a small hole in the RPV Bottom Head may allow some air ingress to the core region. If the Lower Head is intact no air ingress to the RPV would take place. Station blackout scenario resulted in high zirconium oxidation fraction, about 60%. The oxidation fraction in the Bottom Head LOCA case was 14%. In the calculated cases Ru release from the core equaled to 8-23% of the initial core inventory. The highest Ru release was obtained in the station blackout scenario.

M3 - Chapter or book article

SN - 978-951-38-7266-3

T3 - VTT Tiedotteita - Research Notes

SP - 261

EP - 275

BT - SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Zilliacus R, Kekki T, Lindholm I, Suopajärvi A. Release of radioactive materials from a degrading core (RADECO): RADECO summary report. In SAFIR2010: The Finnish Research Programme on Nuclear Power Plant Safety 2007-2010 : Interim Report. Espoo: VTT Technical Research Centre of Finland. 2009. p. 261-275. (VTT Tiedotteita - Research Notes; No. 2466).