K.M. Koo
Universal Monitoring & Inspection, Inc.,
Korea
Keywords: NPPs, nuclear power plants, CB, container building, SAECs, severe accident environmental conditions, SBO, station blackout, loosely coupled coils, wireless power transmissions, DMTC, diagnostic module of telemetry circuit
Summary:
Major nuclear accidents since the 1970s include the TMI (Three Mile Island) nuclear accident in the United States (March 28, 1979, Pennsylvania), the Chernobyl nuclear accident in Ukraine (April 26, 1986), and the Daiichi Fukushima nuclear accident in Japan (March 11, 2011). In particular, in the case of Japanese, the accident occurred as a result of the tsunami along with a magnitude 9.0 earthquake at Fukushima NPP Units 1-4. In these accidents the power supply to all electrical instrumentation and control systems is stopped due to the station blackout (SBO) accident. At this stage, power almost cannot be supplied to the power grid inside container buildings (CB) in the NPPs. A common problem in the nuclear accidents is that the power supply to all electrical instrumentation and control systems is stopped due to the SBO accident. When deviating from the requirements of 10 CFR 50.2, an outage means a complete loss of AC power to the essential and non-essential device buses of a nuclear power plant, concurrently with the loss of the external power system on a cooling water turbine trip. At this stage, power almost cannot be supplied to the power grid inside CB in the NPPs. Therefore, we prepared new alternative methods as loosely coupled coils for wireless power transfer through CB with high strength reinforced concrete walls under SBO conditions, until now using simulation code. At the same time, the supplied power inside the CB can induce an abnormal signal that is out of the error range when the extreme environment (temperature, humidity, pressure, radiant heat, etc.) exceeds the durability standard in the equivalent circuit of the measuring equipment. At this time, it is possible to diagnose the component members of the equivalent circuit by simulating the remote diagnostic circuit module exceeding the range of the reference signal level as circumstance functions like high temperature conditions. At this point, as a new alternative power supply method to deal with severe SBO accidents in nuclear power systems, we propose a technology capable of diagnosing the parts of the instrumentation equivalent circuit according to the internal extreme environment using the wireless power method loosely coupled through the reinforced concrete wall under the station blackout(SBO) condition of the nuclear power plants(NPPs). These technology will be applied widely to nuclear-powered submarines, power transmission of under ground build, and technology of safety and innovation compared to existing solutions in a social base industry.