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An assessment of transient over-power accident in the PGSFR

Jun 26, 2017, 4:50 PM
Room 3 (Yekaterinburg)

Room 3


ORAL Track 3. Fast Reactor Safety 3.2 Core Disruptive Accident




KAERI (Korea Atomic Energy Research Institute) has been developing a preliminary specific design of the PGSFR (Prototype Gen-IV Sodium-cooled Fast Reactor), which is a pool-type sodium cooled fast reactor with a thermal power of 392.2 MW. The PGSFR has an inherent safety characteristic owing to the design to have a negative power reactivity coefficient during all operation modes and it has a passive safety characteristic due to the design of a passive decay heat removal circuit. For an evaluation of the safety features of the PGSFR, a sensitivity analysis has been performed for TOP(Transient Over-Power) which is one of most important DBEs in the PGSFR using MARS-LMR code. MARS-LMR contains the sodium property table including dynamic properties, heat transfer correlations for the liquid metal, and the models describing the flow resistance by wire-wrap spacer in the core, which shows a good agreement with the experimental data conducted in the EBR-II plant and the appropriateness of the models related to liquid metal reactor. For a sensitivity analysis, some design variables are applied to be conservative. An effect of uncertainties is evaluated on a Doppler reactivity and a sodium density. Conservative assumptions are applied to the analysis of the plant responses during the postulated DBAs, which are 102 % of power condition with ANS-79 decay power model, 5.0 seconds delay in opening of AHX and FHX dampers, and loss of off-site power (LOOP) is taken into account. Additionally, one PDHRS and one ADHRS are available in accordance with a single failure criterion and maintenance. As a result, the preliminary specific design PGSFR meets safety acceptance criteria with a sufficient margin during the TOP event and keep accidents from deteriorating into more severe accidents.

Country/Int. Organization

Republic of Korea/Korea Atomic Energy Research Institute

Primary author


Presentation materials