Ⅱ-3. Nuclear Data

RIKEN Accel. Prog. Rep. 47 (2014)

Systematic study of nuclear data for nuclear transmutation

Long-lived ﬁssion products (LLFPs) are problematic radioactive wastes in spent nuclear fuels. Because
LLFPs have long half-lives, special techniques for safe
management and disposal are required. A promising
way to solve this problem is “nuclear transmutation
technology”. The basic concept of this technology isto change LLFPs into “short-lived nuclei” or “stablenuclei” by using various kinds of particle beams fromaccelerators and neutron ﬂux in nuclear reactors. Recently, the use of an accelerator-driven system (ADS)
has been studied globally for this purpose. In Japan,J-PARC1) plans to establish ADS techniques.
From the viewpoint of nuclear data, various kinds ofcross section data for LLFPs are needed to design thenuclear transmutation system reliably. Cross section
data of proton, neutron, and photon induced reactions
on LLFPs are required to establish more eﬀective procedures and to estimate costs. However, as listed inTable 1, most of the experimental data are still unavailable owing to the diﬃculty in preparing enrichedtargets and in handling of activities.

Simultaneously, management of the experimental
nuclear reaction database to survey information, as
shown in Table 1, and theoretical evaluations of thecross sections is also essential. Due to the lack of experimental cross sections, we performed theoretical estimation using the calculation code TALYS6) . Figure 1
shows the total reaction cross sections induced by protons on LLFPs. We were able to determine the crosssections of the order of barn. The impact of this resultmust be assessed and the cost of the transmutation ofLLFPs must be estimated.

Table 1. Half-lives of LLFPs and the current status of
the experimental data of photon, neutron, and proton induced reactions in EXFOR5) . Numbers with andwithout parentheses indicate those of the experimental
works and data points of cross sections or maxwellian
averaged cross section. “-” means no experimental datain EXFOR.

σ[mb]A. Makinaga,∗1 M. Aikawa,∗1 K. Katō,∗1 A. Kohama,∗2 H. Otsu,∗2 and H. Sakurai∗2Nuclei
79

Se
Sr93
Zr99
Tc107
Pd126
Sn
129
I
135
Cs
137
Cs
151
Sm
90

Half-life(year)
65,00029
150,000
210,000
6,500,000
100,000
16,000,000
2,300,000
30
89

2000
1800
1600
1400
1200

∗279
Se
90
Sr
93
Zr
99
Tc
107
Pd
126
Sn
129
I
135
Cs
137
Cs
151

800
600
400

Status of experimental data
photon neutron proton
5(5)
3(8)
16(428)
2(82)
2(2)
1(27)
5(5)
4(4)
3(3)
4(47)
-200
0

Sm

0

20

40

60
80
Ep[MeV]

100

120

Fig. 1. Calculation of total reaction cross sections induced
by protons on LLFPs by using the code TALYS.

One possible way to access the cross sections is theinverse reaction method. For example, neutron capture cross sections can be estimated with photo nuclear
reactions2–4) . In addition, unstable LLFP beams at
the RIBF facility are strong candidates to produce related nuclear data. In order to promote nuclear transmutation technology, the sharing of knowledge and information among researchers in related ﬁelds, e.g., nuclear engineering and nuclear physics, is imperative.
∗1

1000

References
1) J-PARC (http://j-parc.jp/Transmutation/ja/ads-j.html)
2) H. Utsunomiya et al.: Phys. Rev. Lett. 100, 162502(2008).
3) A. Kimura et al.: Jour. Nucl. Sci. Technol. 49, 708(2012).
4) A. P. Tonchev et al.: Phys. Rev. C 82, 054620 (2010).
5) IAEA-EXFOR (https://www-nds.iaea.org/exfor/exfor.htm)
6) A. J. Koning et al.: AIP Conf. Proc. 769, 1154 (2005).

Faculty of Science, Hokkaido University
RIKEN Nishina Center- 72 -