An Integral Effects Test in a zion-like geometry to investigate the effects of pre-existing hydrogen on direct containment heating in the Surtsey Test Facility

Technical Report · Fri Jan 01 00:00:00 EST 1993

OSTI ID:6867203

Allen, M D; Blanchat, T K; Pilch, M ^[1]; Nichols, R T ^[2]

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1. Sandia National Labs., Albuquerque, NM (United States)
2. Ktech Corp., Albuquerque, NM (United States)

The sixth experiment of the Integral Effects Test (IET-6) series was conducted to investigate the effects of high pressure melt ejection on direct containment heating. Scale models of the Zion reactor pressure vessel (RPV), cavity, instrument tunnel, and subcompartment structures were constructed in the Surtsey Test Facility at Sandia National Laboratories. The RPV was modeled with a melt generator that consisted of a steel pressure barrier, a cast MgO crucible, and a thin steel inner liner. The melt generator/crucible had a hemispherical bottom head containing a graphite limitor plate with a 4-cm exit hole to simulate the ablated hole in the RPV bottom head that would be formed by ejection of an instrument guide tube in a severe nuclear power plant accident. The cavity contained 3.48 kg of water, which corresponds to condensate levels in the Zion plant, and the containment basement floor was dry. A 43-kg initial charge of iron oxide/aluminum/chromium thermite was used to simulate corium debris on the bottom head of the RPV. Molten thermite was ejected by steam at an initial pressure of 6.3 MPa into the reactor cavity. The Surtsey vessel atmosphere contained pre-existing hydrogen to represent partial oxidation of the zirconium in the Zion core. The initial composition of the vessel atmosphere was 87.1 mol.% N[sub 2], 9.79 mol.% O[sub 2], and 2.59 mol.% H[sub 2], and the initial absolute pressure was 198 kPa. A partial hydrogen burn occurred in the Surtsey vessel. The peak vessel pressure increase was 279 kPa in IET-6, compared to 246 kPa in the IET-3 test. The total debris mass ejected into the Surtsey vessel in IET-6 was 42.5 kg. The gas grab sample analysis indicated that there were 180 g[center dot] moles of pre-existing hydrogen, and that 308[center dot]moles of hydrogen were produced by steam/metal reactions. About 335 g[center dot]moles of hydrogen burned, and 153 g[center dot]moles remained unreacted.

• Research Organization: Sandia National Labs., Albuquerque, NM (United States)
• Sponsoring Organization: USNRC; Nuclear Regulatory Commission, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6867203
• Report Number(s): SAND-92-1802; ON: DE93006987
• Country of Publication: United States
• Language: English

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