High Throughput Study of Irradiation Hardening
and Embrittlement of Materials Based on High-energy Ion Accelerators
Chonghong Zhang1*, Zhaonan Ding1,
Xianlong Zhang1, Yitao Yang1, Yin Song1,
Xiangbing Liu2, Fei Xue2
1 Institute of Modern
Physics, Chinese Academy of Sciences, Lanzhou 730000, China
2 Suzhou Nuclear Power
Research Institute, Suzhou 215004, China
ABSTRACT: The earliest nuclear
power stations in China are already in the middle and late period. The in-pile
conditions of high temperature, high pressure and neutron irradiation are key
factors influencing the operation safety and the life extension evaluation.
Among them the irradiation hardening and embrittlement of the reactor pressure
vessel (RPV) steel is an important factor. Heavy ion irradiation has long been
used to simulate the neutron irradiation, due to the similar cascade damage by
fast neutrons, the high defect production rate, and the low radioactivity. Anymore,
the high-energy heavy ions as used in the present study (Fe ions with 350 MeV)
can produce a damage layer with a thickness several times larger than the
average grain size of steels, making possible the measurement of bulk property
changes by using the small specimen test techniques. We present a high
throughput study of the irradiation hardening and embrittlement of RPV steels
by the concept of material genome engineering.
First, we setup a method and facilities, including an
irradiation terminal at HIRFL (Heavy Ion Research Facility in Lanzhou) and a
small-specimen test platform. The irradiation terminal facilitates the
irradiation of more than three dose regions at a batch, and enables the control
of specimen temperature from -150 to 600 oC, and enables homogenous
production of defects along depth. The small-specimen test platform facilitates
small punch test at controlled temperature ranging from -190 to 450 oC.
A date analysis method based on finite element method (FEM) was found.
Second, experiments were carried out to investigate
the irradiation hardening and embrittlement of RPV steels. Isochronal annealing
behavior of irradiation hardening of RPV steel specimens irradiated to
0.15/0.20 dpa at -100 oC was investigated. Values of migration energy
of self-interstitial clusters were deducted. Irradiations of RPV steel to
successively increasing damage levels (0.05, 0.1, 0.15, 0.3, 0.6, 1.0, 1.5 dpa)
at 290 oC were performed. Dose dependence of the hardening and
ductility loss of the RPV steel was investigated. Meanwhile, both theoretical
and experimental studies on the effects of the dose rate on irradiation
hardening were carried out, in an effort to get a correlation between the heavy
ion irradiation and the neutron irradiation.
Keywords: RPV steel; radiation damage; heavy ions
Chonghong Zhang has completed his PhD in Institute of Modern Physics (IMP), Chinese Academy of Sciences in 1999, and has been engaged in the research of radiation damage and effects of materials candidate for nuclear reactors. He is now the director of the Department of Energy Materials in IMP-CAS.