[en] The Hanford Engineering Development Laboratory (HEDL) is evaluating utilization of a ²⁵²Cf fuel-pin scanner as a non-destructive assay technique to determine shipper-receiver assays of fissile materials in liquid-metal fast-breeder reactor-type fuel pins. All fast flux test facility (FFTF) fuel pins produced for cores 1 and 2 are being assayed with the fuel scanner. Results have been compared with chemical measurements. In a set of 49 pins, using six scans per pin, no significant differences were observed between non-destructive assay and chemical assay on six randomly selected pellets from each fue pin after it had been destructed. Shipper-receiver differences for outer core fuel pins under HEDL calibration of the fuel-pin scanner agree with chemical shipper-receiver differences within experimental limitations. Quality control data over a two-year period involving 1286 observations for seven fuel-pin standards indicate a long-term random error of 0.84% relative standard deviation per single fuel-pin assay. A random variation of S=0.84% per single fuel-pin assay has little or no effect on the uncertainty in toal Pusub(f) in statistically large numbers of fuel pins. Long-term agreement with given quality control fuel pins ranges form -0.23% to +0.12%. The overal weighted averaged agreement is -0.10%, which indicates an apparent bias trend for the fuel-pin scanner under the present two-point calibration technique. In a large number of fuel pins composing a shipment, the uncertainty for total fissile plutonium, as determined by the fuel-pin scanner, is due to the uncertainty of assay of the fuel-pin standards. (author)