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| NKS Programme Area: | NKS-R | | Research Area: | Severe accidents and Reactor Physics | | Report Number: | NKS-46 | | Report Title: | A Study on Hydrogen Deflagration for Selected Severe Accident Sequences in Ringhals 3 | | Activity Acronym: | SOS-2.3 | | Authors: | Veine Gustavsson, Erik Möller | | Abstract: | In this report, we have investigated the most important severe accident
sequences in Ringhals 3, a Westinghouse 3-loop PWR, concerning hydrogen
generation and containment pressure at hydrogen deflagration. In order to
analyze the accident sequences and to calculate the hydrogen production, the
computer code MAAP (Modular Accident Analysis Program) was used. Six
accident sequences were studied, where four were LOCA cases and two
transients. MAAP gives the evolution of the accident and particularly the
pressure in the containment and the production of hydrogen as a function of
time. The pressure peaks at deflagration were calculated by the method AICCAdiabatic
Isochoric Complete Combustion. The results from these calculations
are conservative for two reasons. Adiabatic combustion means that the heat
losses to structures in the containment are neglected. The combustion is also
assumed to occur once and all available hydrogen is burned.
The maximum pressure in five analysed cases was compared with the failure
pressure of the containment. In the LOCA case, 373 kg hydrogen was burned
and the resulting peak pressure in the containment was 0,53 MPa. In the
transient, where 720 kg hydrogen was burned, the peak pressure was 0,69
MPa. This is the same as the failure pressure of the containment. Finally, in the
conservative case, 980 kg hydrogen was burned and the resulting peak
pressure 0,96 MPa. However, it should be noted that these conclusions are
conservative from two points of view. Firstly a more realistic (than AICC)
calculation of the peak pressure would give a lower value than 0,69 MPa.
Secondly, there is conservatism in the evaluation of the failure pressure. | | Publication date: | 01 Jan 2002 | | ISBN: | ISBN: 87-7893-099-5 | | Number of downloads: | 4766 | | Download: |  NKS-46.pdf |
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