Zirconium Fire Testing at Sandia
ML11031A000, page 58 of 226
Phase 2 will address radial heating and burn propagation and
will include effects of fuel rod ballooning. Five full-length
assemblies will be constructed in which the center assembly
will be of the same heated design as used in Phase 1. The four
peripheral assemblies will be unheated but highly prototypic,
incorporating prototypic fuel tubes and end plugs. These
boundary conditions experimentally represent a “cold neighbor”
situation, which complements the bounding scenario covered by
Phase 1. The peripheral fuel rods will be filled with high density
MgO ceramic, sized to precisely match the thermal mass of spent
fuel. Studies using this test assembly will conclude with a fire
test in which the center assembly is heated to ignition, which
eventually propagates radially to the peripheral assemblies. All
of the fuel rods in two of the four peripheral assemblies will be
pressurized with helium so that these fuel rods will balloon when
the zirconium-alloy cladding reaches a high enough temperature.
The two peripheral assemblies without pressurized rods will serve
as a control for evaluating the effect of ballooning.
Here is one reference that was released on January 3, 2012: (ML113140453) - RES Staff Presentation Handouts Materials NRC-RES/EPRI Coordination Meeting Friday, September 30, 2011, (23 page(s), 12/22/2011). The release on January 3, 2012, disclosed that the corrosion testing of full-length heated bundles of zirconium alloy assemblies is being done at Sandia, it has 12 foreign participants, the full length assemblies are 17 by 17 arrangements of PWR fuel geometry, and testing is being done in air only.
The following cross sections of the zirconium clad heater bundles at Sandia are copied (and enlarged) from ML113140453, page 4 of 23.
As in the previous BWR study, all stages of testing will use
MELCOR modeling results. Pretest MELCOR modeling results
will be used to guide the experimental test assembly design and
instrumentation. MELCOR modeling results will also be used
to choose experimental operating parameters, such as the applied
assembly power. At each step in the testing, improvements
will be made to the MELCOR model to continually increase
confidence in the modeling validity.