Evaluation of flow redistribution due to flow blockage in rod bundles using COBRA code simulation. Final report. [PWR]

Technical Report · Thu Jan 01 04:00:00 EST 1981

DOI:https://doi.org/10.2172/6941932· OSTI ID:6941932

Prelewicz, D. A.; Caruso, M. A.

During a Loss-of-Coolant Accident, fuel rod cladding may reach temperatures approaching 2200/sup 0/F. At these temperatures, swelling and rupture of the cladding may occur. The resulting flow blockage will affect steam flow and heat transfer in the bundle during the period of reflooding. The COBRA-IV-I subchannel computer code was used to simulate flow redistribution due to sleeve blockages in the FLECHT-SEASET 21-rod bundle and plate blockages in the JAERI Slab Core Test Facility. Sensitivity studies were conducted to determine the effects of spacer grid and blockage interaction, sleeve shape effects, sleeve length effects, blockage magnitude and distribution, thermally induced mixing and bundle average velocity on flow redistribution. Pressure drop due to sleeve blockages was also calculated for several blockage configurations.

• Research Organization: NUS Corp., Rockville, MD (USA)
• OSTI ID: 6941932
• Report Number(s): EPRI-NP-1662
• Country of Publication: United States
• Language: English

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