New Intrinsically Smart Severe Accident Instrumentation Saves Costs and Enhances Severe Accident Management

摘要

The Severe Accidents (SA) at Fukushima in 2011, identified the need for enhanced I&C to follow the progress of SA. Since SA environments are significantly Beyond DBA conditions, some new advanced Inherently Smart sensors had to be developed and tested. Nuclear plant designers and operators have helped focus the l&C enhancement based upon lessons learned from the Fukushima accidents. The result has been the addition of I&C for direct measurement of SA conditions hydrogen concentration, oxygen concentration, temperature, and pressure that provide unambiguous information for management of Severe Accident scenarios. The benefits are immediate from three important aspects. First, they deliver on the nuclear promise for enhanced safety at reduced costs. These Inherently Smart sensors have no maintenance and replace equipment that has high maintenance costs. Secondly, these sensors provide multiple benefits, such as condition monitoring information all the time and direct measurement of SA conditions if they are needed. Thirdly, and most importantly, simplify operator actions and training for SA. SA scenarios and SA Management can now rely on direct measurements to know such things as, the extent of fuel damage, integrity of the reactor pressure vessel, when corium is on the floor of containment, and conditions upon which to activate the hardened vent.