Integral experiments of technetium-99 using fast-neutron source reactor ‘YAYOI’

ABSTRACT

The present study performed integral experiments of ⁹⁹Tc by an activation method using a fast-neutron source reactor ‘YAYOI’ of the University of Tokyo to validate evaluated nuclear data libraries: JENDL-4.0, ENDF/B-VII and VIII. Technetium-99 samples were irradiated with reactor neutrons using a pneumatic system, and repeated 74 times to accumulate statistics. Reaction rates of ⁹⁹Tc were obtained by measuring decay gamma rays emitted from ¹⁰⁰Tc. The fast-neutron flux spectrum at the YAYOI was checked with flux monitors and MCNP calculations. The experimental reaction rate of ⁹⁹Tc was compared with the reaction rates given using both the fast-neutron flux spectrum and evaluated nuclear data libraries. The present integral experiments supported the evaluated nuclear data library JENDL-4.0.

KEYWORDS:

• Technetium-99
• technetium-100
• integral experiment
• activation method
• fast-neutron flux spectrum
• fast-neutron source reactor
• yayoi

Acknowledgments

The authors would like to greatly appreciate Professor Emeritus Yoshiaki OKA, Drs. Yuki ISHIWATARI (present affiliation: GE Hitachi), Isao SAITOH, Atsushi YASUMI, Tsutomu NAKAGAWA and Yukio MABUCHI of the University of Tokyo for their cooperation.

One of the authors (S.N.) would also like to express my gratitude to Dr. Osamu IWAMOTO of JAEA for the time and effort dedicated to his constructive and valuable comments.

This work has been carried out in part under a collaborative research project at Nuclear Professional School, School of Engineering, The University of Tokyo.

Disclosure statement

No potential conflict of interest was reported by the author(s).