Fissile and fertile nuclear material measurements using a new differential die-away self-interrogation technique
- Los Alamos National Laboratory
This paper presents a new technique for the measurement of fissile and fertile nuclear materials in spent fuel and plutonium laden materials such as mixed oxide (MOX) fuel. The technique, called differential die-away self-interrogation, is similar to traditional differential die-away analysis, but it does not require a pulsed neutron generator or pulsed beam accelerator, and it can measure the fertile mass in addition to the fissile mass. The new method uses the spontaneous fission neutrons from {sup 244}Cm in spent fuel and {sup 240}Pu effective neutrons in MOX as the 'pulsed' neutron source with an average of {approx} 2.7 neutrons per pulse. The time correlated neutrons from the spontaneous fission and the subsequent induced fissions are analyzed as a function of time to determine the spontaneous fission rate, the induced fast-neutron fissions, and the induced thermal-neutron fissions. The fissile mass is determined from the induced thermal-neutron fissions that are produced by reflected thermal neutrons that originated from the spontaneous fission reaction. The sensitivity of the fissile mass measurement is enhanced by the use of two measurements, with and without a cadmium liner between the sample and the hydrogenous moderator. The fertile mass is determined from the multiplicity analysis of the neutrons detected soon after the initial triggering neutron is detected. The method obtains good sensitivity by the optimal design of two different neutron die-away regions: a short die-away for the neutron detector region and a longer die-away for the sample interrogation region.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC52-06NA25396
- OSTI ID:
- 962283
- Report Number(s):
- LA-UR-08-07211; LA-UR-08-7211; NIMAER; TRN: US0903418
- Journal Information:
- Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 602, Issue 2; ISSN 0168-9002
- Country of Publication:
- United States
- Language:
- English
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