Patent Number: 
Section: claims

1. A system for monitoring a state of a reactor core included in a nuclear reactor, the system comprising:an internal monitoring device located inside the reactor core, the internal monitoring device including,one or more internal sensor arrays each configured to take measurements of conditions at each of a plurality of different vertical regions within the reactor core to generate internal measurement data, the internal monitoring device being configured to provide the internal measurement data to one or more data lines of the nuclear reactor, the one or more internal sensor arrays being configured to take measurements of a conductivity at each of the plurality of different vertical regions, the one or more internal sensor arrays including a conductivity sensor array, the conductivity sensor array including a plurality of conductivity sensors; anda first case, at least a portion of the one or more internal sensor arrays being located within the first case, the first case including a plurality of protrusions, the plurality of protrusions extending outwards above each of the plurality of conductivity sensors, and the plurality of protrusions configured to substantially mitigate coating of each of the plurality of conductivity sensors by molten materials;an external monitoring device located in the reactor structure outside the reactor core, the external monitoring device including one or more external sensor arrays each configured to take measurements of conditions of the reactor core at positions outside the reactor core corresponding to each of the plurality of different vertical regions within the reactor core to generate external measurement data, and a transmitter configured to wirelessly transmit the external measurement data outside the nuclear reactor; anda receiver station configured to receive the external measurement data and the internal measurement data, and to determine a state of the reactor core based on the received external and internal measurement data,wherein the one or more internal sensor arrays are further configured to take measurements of a temperature at each of the plurality of different vertical regions. 2. The system of claim 1, wherein the first case is made from a rigid material having a melting point higher than that of stainless steel. 3. The system of claim 2, wherein the first case is made of at least one of tungsten, molybdenum, niobium and silicon carbide. 4. The system of claim 2, wherein the one or more internal sensor arrays includes a temperature sensor array including a plurality of temperature sensors each corresponding to one of the plurality of different vertical positions within the reactor core. 5. The system of claim 2, whereineach of the plurality of conductivity sensors extends to an outer surface of the first case, and each of the plurality of conductivity sensors corresponds to one of the plurality of different vertical regions within the reactor core. 6. The system of claim 1, wherein the internal monitoring device is located inside a traversing in-core probe (TIP) tube of the reactor core. 7. The system of claim 1, wherein the internal monitoring device further includes a first data processor configured to generate the internal measurement data by digitizing the measurements taken by the one or more internal sensor arrays. 8. The system of claim 1, wherein the internal monitoring device includes a power line configured to receive power from a source external to the internal monitoring device. 9. The system of claim 1, wherein at least one of the one or more external sensor arrays is configured to take measurements of at least one of a gamma flux and a neutron flux of the reactor core. 10. The system of claim 9, wherein the external monitoring device further includes a second case made of at least one of stainless steel, tungsten, molybdenum, niobium and, silicon carbide, at least a portion of the one or more external sensor arrays being located within the second case so as to be enclosed by the second case. 11. The system of claim 9, wherein the one or more external sensor arrays includes a sensing unit array including a plurality of sensing units, each of the plurality of sensing units being configured to measure at least one of a gamma flux and a neutron flux, each of the plurality of sensing units corresponding to one of the plurality of different vertical regions within the reactor core. 12. The system of claim 9, wherein the external monitoring device further includes a power unit configured to power the external monitoring device independently of any external power source. 13. The system of claim 9, wherein the external monitoring device further includes a coupling unit configured to affix the external monitoring device to a surface inside the nuclear reactor, the coupling unit including at least one of a magnet, an adhesive, and a bolting mechanism. 14. The device of claim 9, wherein the external monitoring device further includes a controller configured to,control an operation mode of the external monitoring device to be one of an active mode and a stand-by mode based on the external measurement data,wherein the external monitoring device is configured to operate such that less power is used in the stand-by mode than in the active mode. 15. The device of claim 1 wherein the receiver station includes a data processing unit configured to determine conditions in the reactor core including at least one of cladding oxidation, water level, cladding melting, nuclear reactivity keff and temperature, based on at least one of the external measurement data and the internal measurement data. 16. A device for monitoring a reactor core or a nuclear reactor, the device comprising:a case made from a rigid material having a melting point higher than that of stainless steel, the case being configured to fit inside an internal tube of the reactor core;one or more sensor arrays inside the case, at least one of the one or more sensory arrays being configured to take measurements of at least one of a temperature and a conductivity of the reactor core at each of a plurality of different vertical regions within the reactor core to generate internal measurement data; andone or more internal data lines configured to transfer the internal measurement data to data lines of the nuclear reactor,the one or more sensor arrays includes a conductivity sensor array including a plurality of conductivity sensors, each of the plurality of conductivity sensors extending to an outer surface of the case, each of the plurality of conductivity sensors corresponding to one of the plurality of different vertical regions within the reactor core, andthe case includes a plurality of protrusions extending outwards above each of the plurality of conductivity sensors, the plurality of protrusions configured to substantially mitigate coating of each of the plurality of conductivity sensors by molten materials. 17. The system of claim 16, wherein the case is made of at least one of tungsten, molybdenum, niobium and silicon carbide. 18. The device of claim 16, wherein the case is configured to fit inside a traversing in-core probe (TIP) tube of the reactor core.