RELAP5/MOD3. 1 simulation of inadvertent initiation of SBWR passive safety features

Conference · Fri Jan 01 04:00:00 EST 1993 · Transactions of the American Nuclear Society; (United States)

OSTI ID:7129200

Faust, C R; Hassan, Y A ^[1]

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1. Texas A M Univ., College Station, TX (United States)

The simplified boiling water reactor (SBWR) is a proposed 660-MW(electric) light water reactor plant designed by General Electric Company (GE). The SBWR is the newest of GE's advanced boiling water reactor (BWR) designs, incorporating natural circulation in the reactor coolant system and a host of passive safety features that allow for near-hands-off reactor safety during worst-case accident conditions. These safety features, the automatic depressurization system, the gravity-driven cooling system, the isolation condenser system (ICS), and the standby liquid control system (SLCS), can all be initiated by firing a small direct current charge that opens squib isolation valves. This computational investigation explores the modeled plant response to the inadvertent initiation of the ICS squib isolation valves. The function of the ICS is to provide a passive heat exchanger for the removal of reactor coolant sensible heat and core decay heat during accident conditions. The ICS is composed of three isolation condenser units located in large pools above the containment upper drywell. The system is attached to the reactor via an inlet line connected to the vessel steam dome and a condensate return line into the reactor downcomer. Operation of the system is actuated by firing the charge in the squib valve located downstream of the heat exchanger. This allows flow of steam from the upper steam dome to the ICS cooling pools where it is condensed and returned to the downcomer as condensate. The pools are sized to allow for 3 days of cooling without refilling. The ICS is passive in that the flow patch driving head is the density difference of the working fluid and no alternating-current power is required to open valves or run pumps, but it is nonpassive in that it does require direct-current power to fire the explosive charge in the squib valves.

• OSTI ID: 7129200
• Report Number(s): CONF-931160--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 69
• Country of Publication: United States
• Language: English

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