Induced nuclear reactions: processes – systems – and elements – Handling of fission reactor component structure within... – Storage container systems for new and/or irradiated core...
Reexamination Certificate
1999-08-10
2001-06-26
Jordan, Charles T. (Department: 3641)
Induced nuclear reactions: processes, systems, and elements
Handling of fission reactor component structure within...
Storage container systems for new and/or irradiated core...
C376S247000, C376S250000, C376S254000, C250S370050, C250S370060, C250S370130
Reexamination Certificate
active
06252923
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to monitoring of spent nuclear fuel, and more particularly relates to in-situ, self-powered monitoring of spent nuclear fuel stored in containers.
BACKGROUND INFORMATION
In the packaging of spent nuclear fuel from nuclear reactors for dry storage or shipment, the primary concern is with the reliable containment of the radioactive nuclear fuel in order to prevent unwanted exposure to radiation. To ensure this protection, the container or canister, and its associated surrounding cask, must meet several criteria. The container must provide containment integrity to prevent the release of radioactive material during normal or hypothetical accident conditions, as well as structural integrity in supporting the weight load of the contained fuel. Thermal protection is required to provide adequate dissipation of the decay heat produced by the spent nuclear fuel, to avoid compromising the integrity of the fuel or the materials of the container or cask. Adequate radiation shielding must also be provided to limit the radiation field external to the package to acceptable values. The container must also protect against the possibility of nuclear criticality, since the contained fuel could represent a critical mass if the system's engineered features were removed or sufficiently degraded, or if the fuel geometry were radically altered through structural degradation.
The containers are sealed upon loading, often by double welding, so that re-entry to perform measurements is often not an acceptable option. Instrumentation penetrations are generally regarded as unacceptable because of increased risk of confinement system failure. Because of the uniformity in the manufacture of such systems, monitoring may be performed on a statistically acceptable subset of containers for a given fuel type, to ensure safety of the entire population of containers.
Currently, only coarse methods of monitoring are available, for fuel in dry storage. In some metal cask systems, the performance of metallic O-rings is monitored, to ensure seal integrity. In concrete cask systems in which air flow occurs, periodic monitoring of air outlet temperature is conducted.
The present invention has been developed in view of the foregoing, and to overcome other deficiencies of the prior art.
SUMMARY OF THE INVENTION
The present invention provides a method and apparatus which allow remote monitoring of stored spent nuclear fuel, without breeching the containment boundary of the containers in which the spent nuclear fuel is stored. Detectors can be configured as an integral part of a spent fuel container, or as a measurement probe which can be placed adjacent the spent fuel container while it is contained within a storage cask. Monitoring of the neutron and &ggr;-ray fields could be used to indicate the integrity of the fuel or neutron absorber, and the presence of water in the container. Temperature measurements may also be made to determine the temperature profile in the container. Structural degradation or failure of key components within the container may also be detected.
An object of the present invention is to provide a system for measuring neutron and &ggr;-ray flux emitted from spent nuclear fuel including a container, spent nuclear fuel in the container, and at least one detector positioned to receive the neutron and &ggr;-ray flux from the spent nuclear fuel. Multiple such “neutron and &ggr;-ray” detectors are preferably positioned in an array either inside or outside the container. The neutron and &ggr;-ray detectors preferably include a semiconductor active region comprising silicon carbide or metal. A cask made of concrete or metal may be placed around the container and detectors to provide shielding, support, and impact protection.
Another object of the present invention is to provide a method of measuring neutron and &ggr;-ray flux from spent nuclear fuel, the method comprising the steps of placing spent nuclear fuel in a container, sealing the container, and measuring neutron and &ggr;-ray flux from the spent nuclear fuel with at least one neutron and &ggr;-ray detector. The detector may be sealed inside the container or positioned on the exterior of the container.
Another object of the present invention is to provide a method and apparatus for measuring the temperature of spent nuclear fuel in a container.
Another object of the present invention is to provide a method and apparatus for sensing the structural integrity of key components of containers for spent nuclear fuel.
These and other objects of the present invention will be more apparent from the following description.
REFERENCES:
patent: 3227876 (1966-01-01), Ross
patent: 3805078 (1974-04-01), Kozlov
patent: 3832668 (1974-08-01), Berman
patent: 4267454 (1981-05-01), Playfoot et al.
patent: 4284893 (1981-08-01), Allan et al.
patent: 4419578 (1983-12-01), Kress
patent: 4483816 (1984-11-01), Caldwell et al.
patent: 4687622 (1987-08-01), Longden
patent: 5185122 (1993-02-01), Poppendiek et al.
patent: 5378921 (1995-01-01), Ueda
patent: 5898747 (1999-04-01), Singh
patent: 5969359 (1999-10-01), Ruddy et al.
patent: 000524095A (1993-01-01), None
Byers William A.
Congedo Thomas V.
Dulloo Abdul R.
Fero Arnold H.
Iacovino John M.
Jordan Charles T.
Mun Kyongtaek K.
Westinghouse Electric Company LLC
LandOfFree
In-situ self-powered monitoring of stored spent nuclear fuel does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with In-situ self-powered monitoring of stored spent nuclear fuel, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and In-situ self-powered monitoring of stored spent nuclear fuel will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2439916