Analysis of temperature development and graphite corrosion in the HTR-modul in case of massive air ingress using the REACT/THERMIX computer code
Creators
Description
The activities are presented in three parts: (1) Detailed description of the reaction kinetics involved in the processes induced upon the graphite coming into contact with air. (2) Enhancement of the REACT/THERMIX code. (3) Effects and processes induced by massive air ingress into the HTR-Modul. The results show that during the postulated accidents, the maximum core temperature will remain lower than that expected for a pressure relief accident without air ingress. There will be a time lag of about 1.5 days before onset of decladding of coated particles due to burnup of the fuel-free coating, assuming an inhomogeneous fuel particle burnup. This time period seems to be long enough to allow for measures to be taken to stop the income of air. Up to this moment, a remaining strength of about 50% of the core bottom is calculated to be guaranteed, although the core bottom continuously loses in mass due to the graphite/oxygen reactions. The results show that the hypothetical air ingress accidents in the HTR-Modul will not develop into unpredictable events. (orig./HP)
Abstract (German)
Die Arbeit wurde in drei Teile zusammengefasst: 1) Aufarbeitung der reaktionskinetischen Ablaeufe bei der Umsetzung von Graphit mit Luft; 2) Ertuechtigung des Codes REACT/THERMIX; 3) Auswirkungen und Ablaeufe von massiven Lufteinbruechen in den HTR-Modul. Fazit: Bei den postulierten Stoerfaellen bleibt die maximale Kerntemperatur unter dem Wert beim Druckentlastungsstoerfall ohne Lufteinbruch. Bis die ersten beschichteten Brennstoffteilchen durch den Abbrand der brennstofffreien Schale freigelegt werden, vergehen unter der Annahme eines inhomogenen Brennelement-Abbrandes etwa 1,5 Tage. Diese Zeitspanne erscheint lang genug, um den Luftzustrom zum Reaktorkern zu unterbinden. Fuer den Kernboden, der durch die Graphit/Sauerstoff-Reaktionen bei massiven Lufteinbruechen kontinuierlich an Masse verliert, ist bis dahin eine Restfestigkeit von ca. 50% gewaehrleistet. Die Ergebnisse zeigen, dass die hypothetischen Lufteinbruchstoerfaelle in den Kern des HTR-Moduls nicht zu unueberschaubaren Auswirkungen fuehren. (orig./HP)Additional details
Additional titles
- Original title (German)
- Ermittlung der Temperaturentwicklung und Graphitkorrosion in den HTR-Modul bei massiven Lufteinbruechen mit dem Codesystem REACT/THERMIX
Publishing Information
- Imprint Title
- Accident and safety analyses for the HTR-modul. Partial project 1: Computer codes for system behaviour calculation. Final report. Pt. 1
- Imprint Pagination
- 321 p.
- Journal Page Range
- [93 p.].
- Report number
- INIS-mf--14188
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 25052700
- Subject category
- S21: SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; S21: SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS;
- Descriptors DEI
- AIR INFILTRATION; COATED FUEL PARTICLES; COMPUTER CALCULATIONS; CORROSION; GRAPHITE; HTGR TYPE REACTORS; MASS TRANSFER; MODULAR STRUCTURES; PEBBLE BED REACTORS; PRESSURE RELEASE; R CODES; REACTOR ACCIDENTS; REACTOR SAFETY EXPERIMENTS
- Descriptors DEC
- ACCIDENTS; CARBON; CHEMICAL REACTIONS; COMPUTER CODES; ELEMENTS; FUEL PARTICLES; GAS COOLED REACTORS; GRAPHITE MODERATED REACTORS; HOMOGENEOUS REACTORS; NONMETALS; REACTORS; SOLID HOMOGENEOUS REACTORS
Optional Information
- Contract/Grant/Project number
- Foerderkennzeichen BMFT 03IAT2266
- Notes
- Imprint:Stoerfall- und Sicherheitsanalysen zum HTR-Modul. Teilvorhaben 1: Berechnungen zum Systemverhalten. Schlussbericht. T. 1.
- Secondary number(s)
- SIEMENS-KWU-BT71--92/0023.