Expert system for identification of simultaneous and sequential reactor fuel failures with gas tagging

In a nuclear reactor having a plurality of fuel elements each including an inner fuel rod and an outer cladding disposed about and enclosing said fuel rod in a sealed manner, wherein each fuel element further includes a unique tag gas to assist in detection of a leak from a failed fuel element, a method for identifying a fuel element failure comprising the steps of:

• determining the composition in terms of one or more tag gases of a leaked gas from one or more of the fuel elements and assigning the composition of the leaked gas a tag node M in a first coordinate system;
• translating said tag node M to a second coordinate system wherein said tag node M is at the origin of said second coordinate system;
• generating a plurality of geometric node figures by identifying possible combinations of tag gases, wherein each corner of each of said geometric node figures represents a tag gas from a possible leaking fuel element and wherein the area or volume within all of said geometric figures represents all possible combinations of tag gases from leaking fuel elements;
• selecting only those tag gases within node figures encompassing the origin of said second coordinate system as from possibly leaking fuel elements;
• comparing the node encompassing the origin of said second coordinate system with a predetermined number of most recently leaking fuel element tag gases;
• selecting only those node figures containing said most recently leaking fuel element tag gases;
• defining the selected node figures in terms of a membership contour ranging from 0 to 1, wherein 0 represents 0 probability of a gas tag and 1 represents 100% probability of a gas tag;
• and
• comparing the membership contours of each of the selected node figures with said tag node M for identifying a failed fuel element while compensating for measurement and tag gas composition uncertainties.