Non-invasive in-situ imaging of interior of nuclear reactors

A system for performing non-invasive imaging or monitoring of a reactor core inside a nuclear reactor, wherein the reactor core contains nuclear fuel, the system comprising:

• muon detector arrays placed outside an enclosure of a nuclear reactor to detect hit events, and generate hit signals associated with detected hit events, wherein the muon detector arrays include a first pair of detector array that comprises:
• a first muon detector array at a first surface of the enclosure, wherein the first muon detector array includes muon detectors arranged vertically along a first vertical plane substantially parallel to the first surface of the enclosure;
• and
• a second muon detector array at a second surface of the enclosure opposite to the first surface, wherein the second muon detector array includes muon detectors arranged vertically along a second vertical plane substantially parallel to the second surface of the enclosure, wherein the first vertical plane and the second vertical plane are substantially parallel to each other and are at opposite sides of the nuclear reactor;
• and
• a second pair of detector array that comprises:
• a third muon detector array at a third vertical surface of an enclosure of the nuclear reactor, the third muon detector configured to generate hit signals representing cosmic-ray muons passing through the third muon detector array, entering into the volume defined by the enclosure, and passing through a fourth muon detector array, wherein the third muon detector array includes muon detectors arranged vertically along a third vertical plane that intersects the first vertical plane, the third vertical plane being substantially parallel to the third vertical surface of the enclosure;
• and
• the fourth muon detector array at a fourth vertical surface of an enclosure of the nuclear reactor, the fourth muon detector array configured to generate hit signals representing cosmic-ray muons passing through the fourth muon detector array, entering into the volume defined by the enclosure, and passing through the third muon detector array, wherein the fourth muon detector array includes muon detectors arranged vertically along a fourth vertical plane substantially parallel to the fourth vertical surface of the enclosure, and wherein the third vertical plane and the fourth vertical plane are substantially parallel to each other and at opposing sides of the reactor;
• a signal processor communicatively coupled to the first, the second, the third, and the fourth muon detector arrays, the signal processor configured to:
• collect the generated hit signals from the first and second muon detector arrays representing at least cosmic-ray muons passing through the first and second muon detector arrays and entering or exiting near-horizontally a volume of the nuclear reactor defined by the enclosure and the hit signals from the third and fourth muon detector arrays representing cosmic-ray muons passing through the third and fourth muon detector arrays and entering or exiting near-horizontally the volume of the nuclear reactor;
• and
• an image processor communicatively coupled to the signal processor and configured to generate an image of the reactor core based on the collected hit signals, wherein the image of the reactor core includes an image of the nuclear fuel for determining a status of the reactor core.

A system for non-invasive inspecting a damaged reactor core inside a nuclear reactor, comprising:

• charged particle detector arrays placed outside an enclosure of the damaged nuclear reactor to generate charged particle signals representing charged particles passing through the charged particle detector arrays, entering or exiting near-horizontally a volume defined by the enclosure, and interacting with nuclear fuel inside the damaged reactor core, wherein the charged particle detector arrays include a first pair of detector arrays that comprises:
• a first charged particle detector array at a first position outside the enclosure, wherein the first charged particle detector array is arranged in a first vertical plane substantially parallel to a first vertical surface of the enclosure;
• and
• a second charged particle detector array at a second position outside the enclosure opposite to the first position, wherein the second charged particle detector array is arranged in a second vertical plane substantially parallel to a second vertical surface of the enclosure, wherein the first vertical plane and the second vertical plane are substantially parallel to each other and are at opposite sides of the nuclear reactor;
• and
• a second pair of detector array that comprises:
• a third charged particle detector array at a third position outside the enclosure, wherein the third charged particle detector is arranged in a third vertical plane that intersects the first vertical plane, the third vertical plane being substantially parallel to a third vertical surface of the enclosure;
• and
• a fourth charged particle detector array at a fourth position outside the enclosure opposite to the third position, wherein the fourth charged particle detector array is arranged in a fourth vertical plane substantially parallel to a fourth vertical surface of the enclosure, wherein the third vertical plane and the fourth vertical plane are substantially parallel to each other and are at opposite sides of the nuclear reactors;
• a signal processor communicatively coupled to the first, the second, the third and the fourth charged particle detector arrays to collect the generated charged particle signals from the first and second charged particle detector arrays and from the third and fourth charged particle detector arrays;
• and
• a processor communicatively coupled to the signal processor and configured to perform operations including:
• generate an image of the damaged reactor core based on the collected charged particle signals, wherein the generated image of the damaged reactor core includes an image of the nuclear fuel inside the damaged reactor;
• and
• analyze the image of the nuclear fuel to determine a status of the damaged reactor core including at least one of:
• whether the nuclear fuel is damaged;
• whether the nuclear fuel has been displaced;
• or
• whether the nuclear fuel has at least partially melted.