Time-Spectral Analysis Methods for Spent Fuel Assay Using Lead Slowing-Down Spectroscopy of Spent Fuel

Journal Article · Sun Aug 08 04:00:00 EDT 2010 · IEEE Transactions on Nuclear Science, 57(4):2230-2238

DOI:https://doi.org/10.1109/TNS.2010.2051958· OSTI ID:1000613

Smith, Leon E; Anderson, Kevin K; Ressler, Jennifer J; Shaver, Mark W

Nondestructive techniques for measuring the mass of fissile isotopes in spent nuclear fuel is a considerable challenge in the safeguarding of nuclear fuel cycles. A nondestructive assay technology that could provide direct measurement of fissile mass, particularly for the plutonium (Pu) isotopes, and improve upon the uncertainty of today’s confirmatory methods is needed. Lead slowing-down spectroscopy (LSDS) has been studied for the spent fuel application previously, but the nonlinear effects of assembly self shielding (of the interrogating neutron population) have led to discouraging assay accuracy for realistic pressurized water reactor fuels. In this paper, we describe the development of time-spectral analysis algorithms for LSDS intended to overcome these self-shielding effects. The algorithm incorporates the tabulated energy-dependent cross sections from key fissile and absorbing isotopes, but leaves their mass as free variables. Multi-parameter regression analysis is then used to directly calculate not only the mass of fissile isotopes in the fuel assembly (e.g., Pu-239, U-235, and Pu-241), but also the mass of key absorbing isotopes such as Pu-240 and U-238. Modeling-based assay results using a first-order self-shielding relationship indicate that LSDS has the potential to directly measure fissile isotopes with less than 5% average relative error, over a wide fuel burnup range. Shortcomings in the first-order self-shielding model and methods to improve the formulation are described.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1000613
• Report Number(s): PNNL-SA-69411
• Journal Information: IEEE Transactions on Nuclear Science, 57(4):2230-2238, Journal Name: IEEE Transactions on Nuclear Science, 57(4):2230-2238 Journal Issue: 4 Vol. 57; ISSN 0018-9499; ISSN IETNAE
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
ACCURACY
ALGORITHMS
BURNUP
CROSS SECTIONS
FISSILE
INTERROGATION
NEUTRONS
NUCLEAR FUELS
Neutron spectroscopy
PLUTONIUM
PWR TYPE REACTORS
REGRESSION ANALYSIS
SELF-SHIELDING
SLOWING-DOWN
SPECTROMETER
SPECTROSCOPY
SPENT FUELS
nondestructive assay
nuclear fuel cycle safeguards
nuclear fuels