Chapter 6
Development of the Method to Assay Barely
Measurable Elements in Spent Nuclear Fuel
and Application to BWR 9 Â 9 Fuel
Kenya Suyama, Gunzo Uchiyama, Hiroyuki Fukaya, Miki Umeda,
Toru Yamamoto, and Motomu Suzuki
Abstract In fission products in used nuclear fuel, there are several stable isotopes
that have a large neutron absorption effect. For evaluation of the neutronics
characteristics of a nuclear reactor, the amount of such isotopes should be evaluated
by using burn-up calculation codes. To confirm the correctness of such data
obtained by calculation codes, it is important to assure the precision of the evaluation of the neutron multiplication factor of used nuclear fuel. However, it is known
that there are several hardly measurable elements in such important fission products. Data for the amounts of the hardly measurable elements in used nuclear fuel
are scarce worldwide.
The Japan Atomic Energy Agency (JAEA) had been developing a method to
assess the amounts of these fission products that are hardly measurable and have a
large neutron capture cross section, under the auspices of the Japan Nuclear Energy
Safety Organization. In this work, a measurement method was developed combining a simple and effective chemical separation scheme of fission products from used
nuclear fuel and an inductively coupled plasma mass spectrometry with high
sensitivity and high precision. This method was applied to the measurement
program for the used BWR 9 Â 9 fuel assembly. This measurement method is
applicable to the required measurements for countermeasures to the accident at
the Fukushima Dai-ichi Nuclear Power Plant of Tokyo Electric Power Company
(TEPCO). JAEA has a measurement plan for not only BWR but also PWR fuel.
K. Suyama (*) • G. Uchiyama • H. Fukaya • M. Umeda
Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki-ken 319-1195,
Japan
e-mail: suyama.kenya@jaea.go.jp
T. Yamamoto
Secretariat of Nuclear Regulation Authority, Roppongi-First Bld. 14F, 1-9-9 Roppongi,
Minato-ku, Tokyo 106-8450, Japan
M. Suzuki
Central Research Institute of Electric Power Industry, 2-11-1 Iwadokita, Komae-shi,
Tokyo 201-8511, Japan
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_6
47
Development of the Method to Assay Barely
Measurable Elements in Spent Nuclear Fuel
and Application to BWR 9 Â 9 Fuel
Kenya Suyama, Gunzo Uchiyama, Hiroyuki Fukaya, Miki Umeda,
Toru Yamamoto, and Motomu Suzuki
Abstract In fission products in used nuclear fuel, there are several stable isotopes
that have a large neutron absorption effect. For evaluation of the neutronics
characteristics of a nuclear reactor, the amount of such isotopes should be evaluated
by using burn-up calculation codes. To confirm the correctness of such data
obtained by calculation codes, it is important to assure the precision of the evaluation of the neutron multiplication factor of used nuclear fuel. However, it is known
that there are several hardly measurable elements in such important fission products. Data for the amounts of the hardly measurable elements in used nuclear fuel
are scarce worldwide.
The Japan Atomic Energy Agency (JAEA) had been developing a method to
assess the amounts of these fission products that are hardly measurable and have a
large neutron capture cross section, under the auspices of the Japan Nuclear Energy
Safety Organization. In this work, a measurement method was developed combining a simple and effective chemical separation scheme of fission products from used
nuclear fuel and an inductively coupled plasma mass spectrometry with high
sensitivity and high precision. This method was applied to the measurement
program for the used BWR 9 Â 9 fuel assembly. This measurement method is
applicable to the required measurements for countermeasures to the accident at
the Fukushima Dai-ichi Nuclear Power Plant of Tokyo Electric Power Company
(TEPCO). JAEA has a measurement plan for not only BWR but also PWR fuel.
K. Suyama (*) • G. Uchiyama • H. Fukaya • M. Umeda
Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai-mura, Ibaraki-ken 319-1195,
Japan
e-mail: suyama.kenya@jaea.go.jp
T. Yamamoto
Secretariat of Nuclear Regulation Authority, Roppongi-First Bld. 14F, 1-9-9 Roppongi,
Minato-ku, Tokyo 106-8450, Japan
M. Suzuki
Central Research Institute of Electric Power Industry, 2-11-1 Iwadokita, Komae-shi,
Tokyo 201-8511, Japan
© The Author(s) 2015
K. Nakajima (ed.), Nuclear Back-end and Transmutation Technology for Waste
Disposal, DOI 10.1007/978-4-431-55111-9_6
47