US 5,745,538 AGranted

Self-powered fixed incore detector

AssigneeWestinghouse Electric Corp.

InventorMichael D. Heibel

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Abstract

A self-powered fixed incore detector for a nuclear reactor has a neutron sensitive emitter element having a low neutron absorption cross section, such as a vanadium element, which extends the length of the active fuel region and generates a full length signal representative of full length power. A number of gamma sensitive emitter elements, preferably platinum but alternatively zirconium, cerium, tantalum, or osmium elements, provide sequentially increasing overlap with the neutron sensitive emitter element to define axial regions of the active fuel region and generate apportioning signals. The portion of the full length signal generated by the neutron sensitive emitter element attributable to each of the axial regions of the core are determined from ratios of the apportioning signals generated by the gamma sensitive elements. While the ratioing of the apportioning signals reduces the effects of delayed gamma radiation from the products of fission, the transient response can be further improved by filtering out this component of the apportioning signals generated by the gamma sensitive emitter elements.

Claims10

Dependent claims

A self-powered fixed incore detector for measuring power distribution in a core of a given axial length of a nuclear reactor, said detector comprising:

a neutron sensitive emitter element constructed from a first material having a length extending from a first end of said neutron sensitive emitter element substantially along said given axial length of said core for providing a full length signal;
a number of gamma sensitive emitter elements of different lengths constructed from a second material which is different from the first material, each of said gamma sensitive emitter elements having a first end adjacent said first end of said neutron sensitive emitter element and extending along said neutron sensitive emitter element to provide sequentially increasing overlap with the neutron sensitive emitter element which defines axial regions of said core, and producing apportioning signals which substantially proportionally define the relative power in each of said axial regions of said core;
and
signal processing means which separately compares the signals from adjacent gamma sensitive emitters to define respectively the proportion of the total power represented by the non-overlapping, axial sections between such adjacent gamma emitters, and applies those proportions to the signal from the full neutron sensitive emitter element to provide outputs representative of the power in each of said axial regions of said core.

1 more element

Dependencies are inferred from the claim text.