Nuclear heating calculation for the high flux test module in IFMIF
Daisuke Kaku, Tao Ye, and Yukinobu Watanabe
Department of Advanced Energy Engineering Science, Kyushu University,Kasuga, Fukuoka 816-8580, Japan
The international Fusion Material Irradiation Facility, IFMIF, is being developed by Japan, Europe,
USA and Russia under the umbrella of the IEA. A highly-intense accelerator based deuteron-Lithium
neutron source has been planned in IFMIF. Conceptual nuclear design of this facility has been done inForschungszentrum Karlsruhe (FZK) mainly (1). The neutron energy is distributed up to around 50 MeV,
therefore the behavior of neutrons with energy higher than 14 MeV should be estimated with sufficientaccuracy. For this purpose, several high-energy particle Monte Carlo calculation codes (MCNPX,PHITS, etc.) are now available in combination with recently-released high-energy nuclear data libraries.
We choose the PHITS code(2) to develop a neutronics calculation system for the High
Flux-Test-Module (HFTM) in IFMIF. As the first step, neutron energy spectrum and nuclear heatingover the HFTM are calculated and compared to FZK results in order to examine the applicability of thePHITS code to IFMIF neutronics calculations. The sensitivity of three nuclear data libraries (LA150,JENDL/HE-2004, and NRG2003) to nuclear heating and the validity of KERMA approximation arediscussed. Furthermore, we investigate the influence of the d-Li reaction source term on nuclear heating
using TTY data of the Li(d,n) reaction measured recently in Tohoku University (3).
The configuration used in the present calculation is illustrated in Fig.1. At first, the d-Li source term
has been calculated using QMD model in PHITS, but the calculation result is not in good agreementwith experimental results. Therefore, we use the energy and angular distributions calculated by theMCDelicious code (1) as the source term. The neutron spectrum and nuclear heating in the HFTM arecalculated with LA150 library to compare the previous FZK result, and good agreement is obtained
within 10 %. This indicates that the PHITS code is applicable to IFMIF neutronics. Fig.2 shows thecalculations performed with three libraries (LA150, JENDL/HE-2004, NRG2003) to see the dependenceof the nuclear data libraries on neutron flux and nuclear heating. The difference in the neutron flux isnegligible among three calculations, while the difference in the nuclear heating is rather large (up to50%). It was found that this is due mainly to the difference in the KERMA factor included in thelibraries. Further investigation of the validity of the KERMA approximation and the sensitivity of thed-Li reaction source term will be discussed in our presentation.
References(1) S.P.Simakov, et al., IFMIF neutron source term simulation and neutronics analysis of the high flux
test module . Report FZKA 6743, Karlsruhe,2002(2) H.Iwasa, K.Niita, and T.Nakamura , J.Nucl. Scvi. And Technol.,vol39, pp1142-1151 (2002).
(3) M. Hagiwara et al., J. Fusion Sci. & Technol., 48, 1320 (2005).
nuclear data
LA150 JENDL/HE-2004 NRG2003
neutron heat (kW
3.4
6.6
4.5
photon heat (kW)
4.2
4.5
4.0
total heat (kW)
7.6
11.1
8.5

flux (n/cm2/s)

1014

1013

1012

LA150
Jendl-HENRG2003

10110102030

405060energy (MeV)

Fig.1

Configuration of the lithium target and HFTM

Fig.2

Neutron flux and nuclear heating