Year
2007
Abstract
The Advanced Spent Fuel Conditioning Process (ACP), a kind of pyroprocess, has been developed at the Korea Atomic Energy Research Institute (KAERI). Since there is no IAEA safeguards criteria for this process, KAERI has developed a neutron coincidence counter to make it possible to perform a material control and accounting (MC&A) for its ACP materials for the purpose of a transparency in the peaceful uses of nuclear materials at KAERI. The test results of the ACP Safeguards Neutron Counter (ASNC) show a satisfactory performance for the Doubles measurement with a low measurement error in its cylindrical sample cavity. The neutron detection efficiency is about 21% with an error of ±1.32% along the length of the cavity. Using two Cf-252 neutron sources, we obtained various parameters for the Singles and Doubles for the ASNC. The Singles, Doubles, and Triples rates for a Cf-252 point source were obtained by using the MCNPX code simulation and the results for the ft8 cap tally option with the values of e, fd, and ft measured with a strong source most closely match the measurement results within a 1% error. A preliminary calibration curve for the ASNC was generated by using the relationship in the point model equation between Cm-244 and Cf-252 nuclides and the calibration coefficient for the non-multiplying sample is 2.78 × 105 [Doubles counts/s/g Cm-244]. The preliminary calibration curves for the ACP samples were also obtained by using the MCNPX simulation. A neutron multiplication influence on an increase of the doubles rate for the metal ingot and UO2 powder is clearly observed.