Chapter 4
Development of Nondestructive Assay
of Fuel Debris of Fukushima Daiichi NPP (2):
Numerical Validation for the Application
of a Self-Indication Method
Tadafumi Sano, Jun-ichi Hori, Yoshiyuki Takahashi, Hironobu Unesaki,
and Ken Nakajima
Abstract To perform decommissioning of the Fukushima Daiichi NPP safely, it is
very important to measure the components of the fuel debris. Therefore, a new
nondestructive assay to identify and quantify the target nuclide in fuel debris using
a pulsed-neutron source is under development in Kyoto University Research Reactor Institute.
We use the self-indication method for the nondestructive assay. This method is a
neutron transmission method. The neutron transmission method is focused on
resonance reactions (i.e., capture, fission) at the target nuclide. In the self-indication
method, the transmitted neutrons from the sample are injected into an indicator. The
indicator consists of a high-purity target nuclide. The transmitted neutrons are
obtained by the time-of-flight (TOF) technique via resonance reactions in the
indicator. The self-indication method has a high signal-to-noise (S/N) ratio compared to the conventional method.
In this study, numerical validation for the self-indication method to identify and
quantify nuclides in a BWR-MOX pellet is described. The burn-up of the MOX
pellet is 0 GWd/t, 10 GWd/t, 20 GWd/t, 30 GWd/t, 40 GWd/t, and 50 GWd/t. The
12-m measurement line in KUR-LINAC is simulated as a calculational geometry.
Numerical calculations are carried out by continuous-energy Monte-Carlo code
MVP2 with JENDL-4.0 as the nuclear data library. The burn-up calculations of the
BWR-MOX pellet are performed by the deterministic neutronics code SARC 2006
with JENDL-4.0.
Numerical validation for application of the self-indication method is carried out.
From the results, it is noted that the self-indication method has a good S/N ratio
compared to the neutron transmission method for quantifying the amount of target
nuclides in the fuel debris.
T. Sano (*) • J. Hori • Y. Takahashi • H. Unesaki • K. Nakajima
Kyoto University Research Reactor Institute, 1010, Asashiro-nishi-2, Kumatori-cho,
Sennan-gun, Osaka, Japan
e-mail: t-sano@rri.kyoto-u.ac.jp
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_4
31
Development of Nondestructive Assay
of Fuel Debris of Fukushima Daiichi NPP (2):
Numerical Validation for the Application
of a Self-Indication Method
Tadafumi Sano, Jun-ichi Hori, Yoshiyuki Takahashi, Hironobu Unesaki,
and Ken Nakajima
Abstract To perform decommissioning of the Fukushima Daiichi NPP safely, it is
very important to measure the components of the fuel debris. Therefore, a new
nondestructive assay to identify and quantify the target nuclide in fuel debris using
a pulsed-neutron source is under development in Kyoto University Research Reactor Institute.
We use the self-indication method for the nondestructive assay. This method is a
neutron transmission method. The neutron transmission method is focused on
resonance reactions (i.e., capture, fission) at the target nuclide. In the self-indication
method, the transmitted neutrons from the sample are injected into an indicator. The
indicator consists of a high-purity target nuclide. The transmitted neutrons are
obtained by the time-of-flight (TOF) technique via resonance reactions in the
indicator. The self-indication method has a high signal-to-noise (S/N) ratio compared to the conventional method.
In this study, numerical validation for the self-indication method to identify and
quantify nuclides in a BWR-MOX pellet is described. The burn-up of the MOX
pellet is 0 GWd/t, 10 GWd/t, 20 GWd/t, 30 GWd/t, 40 GWd/t, and 50 GWd/t. The
12-m measurement line in KUR-LINAC is simulated as a calculational geometry.
Numerical calculations are carried out by continuous-energy Monte-Carlo code
MVP2 with JENDL-4.0 as the nuclear data library. The burn-up calculations of the
BWR-MOX pellet are performed by the deterministic neutronics code SARC 2006
with JENDL-4.0.
Numerical validation for application of the self-indication method is carried out.
From the results, it is noted that the self-indication method has a good S/N ratio
compared to the neutron transmission method for quantifying the amount of target
nuclides in the fuel debris.
T. Sano (*) • J. Hori • Y. Takahashi • H. Unesaki • K. Nakajima
Kyoto University Research Reactor Institute, 1010, Asashiro-nishi-2, Kumatori-cho,
Sennan-gun, Osaka, Japan
e-mail: t-sano@rri.kyoto-u.ac.jp
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_4
31