Atomic Energy Science and Technology ›› 2022, Vol. 56 ›› Issue (5): 961-968.

### Macroscopic Validation of Nuclear Data in Leadbased Reactor Based on VENUS-Ⅱ Facility

JIANG Wei;ZHANG Lu;YU Rui;GU Long

1. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China;Lanzhou University, Lanzhou 730000, China;University of Science and Technology of China, Hefei 230026, China
• Online:2022-05-20 Published:2022-05-20

### 基于启明星Ⅱ号的铅基堆核数据宏观检验

1. 中国科学院 近代物理研究所，甘肃 兰州730000；中国科学院大学，北京100049；兰州大学，甘肃 兰州730000；中国科学技术大学，安徽 合肥230026

Abstract: Lead-based fast reactor (LFR) is one of the advanced reactor concepts elected in the generation Ⅳ forum of international nuclear energy. Lead-based materials, including lead and leadbismuth, are used as coolant in the reactor core. The LFR core has the strong abilities of nuclear fuel proliferation and spent fuel transmutation, which is due to the fact that the neutron spectrum is very hard. The reactor core with the high inherent safety runs at atmospheric pressure, which can reduce the probability of coolant accident loss accident. Leadbased fast reactor is of vital importance to promote the sustainable development of nuclear energy in China. At present, the large uncertainties in the nuclear cross section data still exist in the neutronics simulations in the leadbased reactor. VENUSⅡ leadbased zeropower reactor, in which the neutron flux spectrum is close to that in the lead-based reactor, can be used to carry out the macroscopic validations of nuclear data of the materials in the lead-based reactor. In this paper, the reactor reactivity of VENUS-Ⅱ lead-based zero-power reactor in the supercritical state was measured by the period method, and the effective multiproliferation factor keff was obtained as 1001 14±0000 07. Meanwhile, the leadbased reactor model was accurately built by the MCNP code, and keff of the supcritical reactor in the experiment was calculated by MCNP with four worldwide cross section libraries (ENDF/BⅦ.0, ENDF/BⅦ.1, CENDL-3.1 and JENDL-4.0). The results show that the keff values calculated by the four cross section libraries are in good agreement with the experimentally measured one, and the maximum relative deviation is less than 1%. And the calculated result with ENDF/BⅦ.1 shows a better agreement with the experiment one and the relative and absolute deviations are respectively 025% and 251 pcm. For the interlibrary comparison, a single ENDF/B-Ⅶ.1 element was substituted with other libraries and the small changes in the keff value were calculated by MCNP code. It is found that the lead element causes the largest change in the keff, and the lead nuclear data in CENDL-3.1 and JENDL-4.0 respectively causes the keff change value of 219 pcm and 166 pcm. By comparing the fission rates in the fuel rods, it is concluded that keff values positively correlated with fission rates in the fuel rods. The fission rate results of ENDF/BⅦ.1 and other libraries show the largest difference in the fifth ring fuel rods of the reactor. The neutron spectrum curves calculated by the four libraries are almost consistent, and the shape of the neutron spectra is mainly determined by the nuclear fuel material and the matrix material. In this work, the nuclear data of some materials in the leadbased reactor have been primarily validated, which can provide the important reference for the subsequent neutronics experiments on VENUSⅡ leadbased reactor.