# 15th Varenna Conference on Nuclear Reaction Mechanisms

Jun 11 – 15, 2018
Villa Monastero
Europe/Zurich timezone

## Nuclear reaction study for high-level radioactive waste: Cross section measurements for proton- and deuteron-induced spallation reactions of long-lived fission products

Jun 14, 2018, 11:30 AM
20m
Villa Monastero

Varenna (Italy)

He Wang

### Description

The disposal of high-level radioactive waste from nuclear power plants is one of the major issues in worldwide. As a promising solution, research and development has been devoted to the partitioning and transmutation technology where long-lived nuclides are converted to stable or short-lived ones. In particular, the transmutation on the long-lived fission products (LLFPs) has received much attention because the LLFP nuclei have large radiotoxicities and they can be produced continuously in the accelerator driven systems and next-generation nuclear reactors. However, experimental reaction data for LLFP nuclei are very limited.

Aiming at bringing a new invention to the nuclear transmutation on LLFP, we have performed a series of systematic studies on the proton- and deuteron-induced spallation for the long-lived fission products ($^{90}$Sr,$^{93}$Zr,$^{107}$Pd,$^{126}$Sn,$^{137}$Cs) at reaction energies ranging from 50 to 200 MeV/nucleon at RIKEN Radioactive Isotope Beam Factory. The inverse kinematics technique was adopted. Namely, LLFP beams were used and proton/deuteron targets were conducted to induce the reactions. Our study on $^{137}$Cs and $^{90}$Sr [1] is the first attempt in the history of nuclear physics to solve the problem of the LLFP transmutation and has triggered the reaction studies for other long-lived fission products.

The present work focuses on $^{137}$Cs, $^{90}$Sr and $^{107}$Pd. Cross sections on proton/deuteron were successfully obtained for these three nuclei and both target and energy dependence of reactions were investigated. In addition, the newly obtained data were compared with the nuclear interaction model including both intra-nuclear cascade and evaporation processes in the frame work of the Particle and Heavy Ion Transport code System (PHITS). In the presentation, the results for LLFP nuclei $^{137}$Cs, $^{90}$Sr [1] and $^{107}$Pd [2] as well as the potential of spallation reaction on the LLFP transmutation will be discussed.

This work was supported and funded by the ImPACT program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan).

[1] H. Wang, H. Otsu, H. Sakurai et al., Phys. Lett. B 754, 104(2016).
[2] H. Wang, H. Otsu, H. Sakurai et al., Phys. Theor. Exp. Phys. 2017, 021D01 (2017).

### Primary authors

He Wang Dr Hideaki Otsu (RIKEN NIshina Center) Hiroyoshi Sakurai (RIKEN) Dr Satoshi Takeuchi (Tokyo Institute of Technology) Yukinobu Watanabe (Kyushu University) Dr Shoichiro Kawase (Kyushu University) Dr Toshiyuki Sumikama (RIKEN Nishina Center) Dr Nobuyuki Chiga (RIKEN Nishina Center)