An analysis of initiating and transition phases for an unprotected loss-of-flow accident in an axially heterogeneous fast breeder reactor core

Journal Article · Sun Mar 01 04:00:00 EST 1987 · Nucl. Technol.; (United States)

OSTI ID:6611475

Azekura, K; Umegaki, K; Inoue, K; Rhow, S K; Mc Elroy, J E; Switick, D M

An unprotected loss-of-flow (LOF) event has been analyzed for a 1000-MW (electric) axially heterogenous core (AHC) at the end of an equilibrium cycle, using a realistic model to evaluate the AHC safety potential. The SAS3D code was used for the initiating phase analysis, while a phenomenological approach was employed for the transition phase. The SAS3D results showed that the system rapidly approached subcriticality after experiencing a benign power burst, because of axially flattened fuel worth distribution and reduced sodium-void worth particularly around the core center. During the transition phase, fuel-steel discharge into the interassembly gaps, coupled with engagement of the upper axial blanket material in the core region, was found to result in permanent subcriticality and nonenergetic termination of the LOF event.

• Research Organization: Energy Research Lab., Hitachi, Ltd., 1168 Moriyama-cho, Hitachi-shi, Ibaraki-ken 316
• OSTI ID: 6611475
• Journal Information: Nucl. Technol.; (United States), Journal Name: Nucl. Technol.; (United States) Vol. 76:3; ISSN NUTYB
• Country of Publication: United States
• Language: English

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