SEDL / STP / STP1228-EB / STP15120S

The Modified Notched Neutron Spectrum Technique for the Surveillance of Hydrogen in Reactor Materials

Miller, WH
Professor, Nuclear Engineering Program, University of Missouri, Columbia, MO

Pages: 9    Published: Jan 1994

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Abstract

The determination of hydrogen content in power reactor materials is a component of an overall surveillance program. Unfortunately, techniques that accurately and nondestructively measure hydrogen content at parts-per-million (ppm) levels have not previously been available. One possible hydrogen measuring technique is based upon the “notched neutron spectrum technique” that has been implemented by EG&G Idaho to characterize hydrogen content in reactor materials for the U.S. Navy. Modifications to this technique have already been demonstrated that increase its sensitivity and utility, allowing for a current accuracy of 0.4 micrograms of hydrogen per gram of steel or an equivalent weight of 6 micrograms in a typical steel sample. This paper describes further tests that have increased the dynamic range of these measurements and provided verification of the absolute calibration of the method.