Hydrogen measurement in cladding material by neutron transmission analysis

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Transactions of the American Nuclear Society

OSTI ID:678125

Hilton, B A ^[1]; Klann, R T ^[2]

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1. Argonne National Lab., Idaho Falls, ID (United States)
2. Argonne National Lab., IL (United States)

Hydrogen absorption in light water reactor fuel cladding is one phenomenon that limits the operating life under normal conditions. In failed fuel, the potential for secondary degradation by hydriding and the subsequent radionuclide release in the primary system is a current concern. The characterization of hydrogen or hydrides in fuel cladding supports efforts to safely extend operation of fuel elements at high burnup or after pinhole leaks develop. Destructive techniques for measuring hydrogen concentration of zirconium fuel elements are well developed. A number of nondestructive techniques such as neutron radiography, neutron scattering, and ultrasound have been reported. Neutron transmission analysis is feasible to use as a nondestructive technique for determining hydrogen content in zirconium fuel rod claddings. Two sample geometries with equivalent hydrogen linear density that ranged between 0 and 12 mg/cm{sup 2} were studied. Sample A was a mockup of the maximum transmission path length of a typical boiling water reactor (BWR) fuel rod cladding (12.3-mm diameter, 0.76-mm thickness) that can be tested without interference of the fuel pellet. Sample B was a mockup of the transmission path length through the diameter of a BWR fuel rod (i.e., twice the cladding wall thickness and the fuel pellet diameter). The dependence of the mass signals for samples A and B on equivalent hydrogen linear density is shown. The mass signals from samples A and B show the same dependence (i.e., slope) on equivalent hydrogen, which indicates that the thin slab assumptions are valid for this application. The y-intercepts of the mass signals are offset by a constant that corresponds to the differences in attenuation of the fuel and zirconium sections. The standard deviation of the mass signal measurements was {+-}0.003. This translates to an uncertainty of {+-}0.122 mg/cm{sup 2} in the hydrogen linear density, which is equivalent to {+-}230 ppm hydrogen for BWR fuel rod dimensions.

• OSTI ID: 678125
• Report Number(s): CONF-990605--
• Journal Information: Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 80; ISSN TANSAO; ISSN 0003-018X
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
40 CHEMISTRY
BWR TYPE REACTORS
FUEL CANS
FUEL RODS
HYDROGEN
NEUTRON TRANSPORT
POLYETHYLENES
RADIATION ABSORPTION ANALYSIS
URANIUM
ZIRCONIUM