Abstract Apparatus for detecting reactor fuel element failures within an assembly of fuel elements in which a sampling device with a test chamber is disposed over an assembly of sealed fuel elements after a nuclear power plant has been shut down and preparation for fuel removal has been completed. Air is conducted through the sampling device to displace the coolant, such as water, in the test chamber above the assembly of fuel elements and to inhibit the circulation of the coolant about the assemblies of fuel elements. As a consequence thereof, the fuel elements of an assembly of fuel elements become heated and fission products are emitted from the defective fuel elements to cause an increase of radio-activity in the water about the assembly of fuel elements. Coolant within or about the assembly of fuel elements is then removed by the sampling device and conducted to a sampling station. At the sampling station is a vial containing a chemical to concentrate the fission products such as an iodine getter, which is exposed to the coolant conducted to the sampling station. The vials containing sample coolant concentrate are moved from the sampling station to a gamma scanner. The gamma scanner senses the activity level of the selected isotope contained in the coolant sample, which is used for detecting the failure of fuel elements within an assembly of fuel elements.
Apparatus as claimed in claim 1, wherein the sample analysis station is located on the platform, and means are provided for carrying the sample from the rigid conduit up to the platform.
Claim 2
Dependent Claim
139 words
Apparatus for detecting fuel element failure in a plurality of assemblies of fuel elements disposed in reactor coolant and in which each fuel assembly comprises an upper end containing openings for coolant flow, comprising a test chamber for disposal over the upper end of said assemblies in liquid-tight relation therewith, means for displacing the coolant in said chamber above said assemblies whereby said fuel elements become heated for increasing the release of fission products from failed fuel elements into the coolant, means associated with each of said plurality of assemblies for removing substantially simultaneously coolant samples from within the associated fuel assembly and below its upper end, said coolant sample removal means comprising a plurality of rigid conduits, a common member supporting said rigid conduits, and means for vertically moving the common member with respect to the test chamber.
Claim 3
Dependent Claim
204 words
Apparatus for detecting the failure of a sealed reactor fuel element in an assembly of fuel elements disposed in reactor coolant and in which the fuel assembly comprises an upper end containing openings for coolant flow, comprising a test chamber for disposal over the upper end of said assembly in liquid-tight relation therewith, means for displacing the coolant in said chamber above said assembly whereby said fuel elements become heated for increasing the release of fission products from failed fuel elements into the coolant, means for removing a sample of the coolant at a location below the said assembly upper end, said coolant sample removal means comprising a rigid conduit extending through said chamber and having a length enabling extension of the free end of said conduit through a coolant flow opening in the assembly upper end, means for vertically moving said rigid conduit relative to the test chamber and the fuel assembly, said fuel assembly having a bale for lifting same, and means in the chamber for engaging the bale and for aligning said test chamber by means of the bale relative to the fuel assembly such that the rigid conduit is aligned with a coolant flow opening in the assembly upper end.
Claim 4
Dependent Claim
22 words
Apparatus as claimed in claim 4, wherein the test chamber comprises at least one internal grapple for connection to the fuel assembly.