Sunday, April 18, 2010

For Emphasis: Single rod tests do not cut it!

Oxidation tests where single rod or tubing specimens are inductively heated do not yield conservative data for the temperature at which runaway is initiated.

The opening statement in PMR-50-93 is founded on sound science, “Petitioner requests that the United States Nuclear Regulatory Commission ("NRC") revise 10 C.F.R. § 50.46(b)(1) to require that the calculated maximum fuel element cladding temperature not exceed a limit based on data from multi-rod (assembly) severe fuel damage experiments.”

Petitioner is submitting this petition, dated November 17, 2009, because
Petitioner is aware that data from multi-rod (assembly) severe fuel damage experiments (e.g., the LOFT LP-FP-2 experiment) indicates that the current 10 C.F.R. § 50.46(b)(1) PCT limit of 2200 degrees Fahrenheit is non-conservative. Data from such experiments also indicates that the Baker-Just and Cathcart-Pawel equations are both non-conservative for calculating the temperature at which an autocatalytic (runaway) oxidation reaction of Zircaloy would occur in the event of a LOCA. This, in turn, indicates that the Baker-Just and Cathcart-Pawel equations are both non-conservative for calculating the metal-water reaction ratesthat would occur in the event of a LOCA.

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