Axial power profiles in SRP reactors during LOCA

Technical Report · Fri Jun 26 04:00:00 EDT 1987

OSTI ID:6953543

Pevey, R E

Detailed analysis of the consequences of a large-break LOCA requires knowledge of the deposited power distribution in each assembly of the core. The deposited power distribution in an assembly can be considered to consist of radial, axial, and time-dependent components. The radial power distribution can be determined from the GLASS lattice calculations; the total deposition rate following scram can be determined using standard reactor kinetics models. This study was undertaken to determine the third component - the axial power shapes following a LOCA-induced scram. Since falling safety rods distort the axial power shape, a one-dimensional transient diffusion theory code was written and applied to the standard beginning-of-life Mark 22 and Mark 16-31A clusters. The results show that the pre- and post-scram axial power profiles are flattened cosines with a maximum/average ratio of about 1.4, but that during the scram, the falling rods cause the power profiles to distort. At the maximum distortion, occurring when the rods have fallen half way into the core, the maximum/average power ratio has increased to almost 1.6 and the peak of the profile occurs 3/4ths of the way down the active length (i.e., at about 750 veeder units insertion.) 1 ref., 6 figs., 2 tabs.

• Research Organization: Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.
• DOE Contract Number: AC09-76SR00001
• OSTI ID: 6953543
• Report Number(s): DPST-87-511; ON: DE89003447
• Country of Publication: United States
• Language: English

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ACCIDENTS
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FLUID MECHANICS
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