6.3 Future Plans
Initially, this measurement technique and procedure have been developed to obtain
experimental data for the demonstration of the neutronics calculation code. However, after the accident at the Fukushima Dai-ichi Nuclear Power Plant in 2011, it is
recognized that the measurement of the isotopic composition of the used nuclear
fuel is crucial to take countermeasures to the accident. We expect that measurement
of the amounts of many varieties of isotopes is required for the decommissioning of
the Fukushima Dai-ichi site.
To accumulate experience and recheck the measurement procedure, JAEA has
already started the measurement campaign after the Fukushima accident. The first
PIE sample was taken from the same fuel assembly used in the PIE campaign
described in the earlier sections. In 2012, one fuel sample was taken from the ZN3
fuel assembly irradiated in Fukushima Dai-ni nuclear power plant unit 1 and the
dissolution was conducted in 2013. It is expected that the measurement results will
be obtained in F.Y. 2014.
JAEA will also assay the isotopic composition of spent nuclear fuel irradiated in
PWR. It is planned to measure the isotopic compositions of nine samples taken
from NO4F69 fuel assembly irradiated in Ohi Nuclear Power Station unit 4 of the
Kansai Electric Power Co., Inc. (KEPCO). The nine PIE samples will be taken from
three fuel rods including UO 2 and UO 2 -Gd 2 O 3 whose average burn-up values are
estimated to be from 40 to 57 GWd/t approximately. This measurement campaign
was started in 2013, and the first results are hoped to be seen in 2014.
6.4 Conclusion
The Japan Atomic Energy Agency had been active in the field of postirradiation
examinations since the 1980s. Based on past experience and introducing the stateof-the-art technique, JAEA began a measurement program of fission products that
are important for reactivity assessment. By this program, the quantitative analytical
method based on isotopic dilution technology has been developed for fission
products in spent fuels. JAEA will carry out the measurement program of isotopic
composition of the used nuclear fuel for countermeasures to the accident at
Fukushima Dai-ichi Nuclear Power Station. This program consists of the measurement of several samples not only from BWR but also PWR. The obtained results
will be used for the evaluation of the burnup code system. Also, the experience of
treating spent fuel and measuring its isotopic composition will strengthen the
technical ability of JAEA for providing countermeasures for the Fukushima
accident.
Acknowledgments The authors thank the following staff in charge of the measurement program
in JAEA: K. Tonoike, M. Amaya, M. Umeda, T. Sonoda, K. Watanabe, N. Shinohara, M. Ito,
6 Development of the Method to Assay Barely Measurable Elements in Spent. . .
55
Initially, this measurement technique and procedure have been developed to obtain
experimental data for the demonstration of the neutronics calculation code. However, after the accident at the Fukushima Dai-ichi Nuclear Power Plant in 2011, it is
recognized that the measurement of the isotopic composition of the used nuclear
fuel is crucial to take countermeasures to the accident. We expect that measurement
of the amounts of many varieties of isotopes is required for the decommissioning of
the Fukushima Dai-ichi site.
To accumulate experience and recheck the measurement procedure, JAEA has
already started the measurement campaign after the Fukushima accident. The first
PIE sample was taken from the same fuel assembly used in the PIE campaign
described in the earlier sections. In 2012, one fuel sample was taken from the ZN3
fuel assembly irradiated in Fukushima Dai-ni nuclear power plant unit 1 and the
dissolution was conducted in 2013. It is expected that the measurement results will
be obtained in F.Y. 2014.
JAEA will also assay the isotopic composition of spent nuclear fuel irradiated in
PWR. It is planned to measure the isotopic compositions of nine samples taken
from NO4F69 fuel assembly irradiated in Ohi Nuclear Power Station unit 4 of the
Kansai Electric Power Co., Inc. (KEPCO). The nine PIE samples will be taken from
three fuel rods including UO 2 and UO 2 -Gd 2 O 3 whose average burn-up values are
estimated to be from 40 to 57 GWd/t approximately. This measurement campaign
was started in 2013, and the first results are hoped to be seen in 2014.
6.4 Conclusion
The Japan Atomic Energy Agency had been active in the field of postirradiation
examinations since the 1980s. Based on past experience and introducing the stateof-the-art technique, JAEA began a measurement program of fission products that
are important for reactivity assessment. By this program, the quantitative analytical
method based on isotopic dilution technology has been developed for fission
products in spent fuels. JAEA will carry out the measurement program of isotopic
composition of the used nuclear fuel for countermeasures to the accident at
Fukushima Dai-ichi Nuclear Power Station. This program consists of the measurement of several samples not only from BWR but also PWR. The obtained results
will be used for the evaluation of the burnup code system. Also, the experience of
treating spent fuel and measuring its isotopic composition will strengthen the
technical ability of JAEA for providing countermeasures for the Fukushima
accident.
Acknowledgments The authors thank the following staff in charge of the measurement program
in JAEA: K. Tonoike, M. Amaya, M. Umeda, T. Sonoda, K. Watanabe, N. Shinohara, M. Ito,
6 Development of the Method to Assay Barely Measurable Elements in Spent. . .
55