Analysis of loss-of-coolant accidents in the advanced neutron source reactor.

摘要

The RELAP5 computer code and a model of the Advanced Neutron Source (ANS) were used to simulate system response to hypothetical loss-of-coolant accidents (LOCAs). The computer code was modified to represent the thermal-hydraulic phenomena expected within the ANS reactor core. The ANS model is biased on the final preconceptual ANS design; the ANS is currently in the conceptual design development stage. This effort represents a first detailed study of ANS transient system response during accidents. The RELAP5 computer code, its modifications, and the ANS system model are described. Analyses of simulations for large, medium, and small break LOCAs in various main coolant pipe locations and for a pressurizing line break are presented. The results indicate that fuel damage is experienced in the ANS preconceptual design for the medium and large break LOCAs. The effectiveness of employing a gas-charged accumulator on the primary coolant system to prevent core damage is investigated with sensitivity calculations. These investigations indicate that fuel damage is prevented for the medium breaks (but not for the large breaks) if a 10-m(sup 3) nitrogen-charged accumulator is used on the hot leg. Analysis uncertainties are addressed and recommendations for reducing them are advanced. 14 refs., 117 figs., 13 tabs.