Significant Breakthrough in Radiation Proof Cement
“The 7th China National Cement Enterprise Chief Engineer Forum and 2014 Annual Meeting of the Special Cement Branch” was held in Wuhan on November 14th. The meeting widely invited industrial experts, senior scholars, business elites. The theme of the meeting is “Special Cement, Energy Efficiency Improvement, Collaborative Disposal” and the aim was to carry out technical exchanges and symposium, to expand the application fields of special cement, speed up the upgrading independent innovation ability and level, promote energy saving and emission reduction, common technical progress, sustainable and healthy development of the cement industry.
Prof. Tian Jian, Dean of Hubei University Tianshu IRDI, invited by the meeting organizers to attend this meeting, and he made a speech of “New Radiation Proof Cement”. Prof. Tian Jian’s special report focused on project profile, technology backgrounds, research results and prospects. The speech attracted high attentions and praises of the participating experts and scholars.
In nowadays society, fossil fuels such as coal, oil and natural gas are over exploited, and they are on the verge of drying up. The world energy crisis and environmental pollution are becoming more and more serious. Wind power, solar photovoltaic, hydropower and other clean energy with high hopes have various kinds of limitations, and their prospect is not optimistic. While nuclear power has a durable, economic, safe and clean and other advantages, with the most development value and potential. The sustainable development of nuclear power can not only ensure the smooth development of the national economy, but also has important strategic significance to national security. So that the development of nuclear power is an inevitable choice for the future. In the face of severe situations of serious resource constraints, environmental pollution and ecosystem degradation, vigorously develop the use of new clean energy, especially for the development and utilization of nuclear power, is a strategic step to adjust the national energy structure, change the mode of economic development, promote green development, recycle development, low carbon development, promote social harmony and healthy development, and the construction of beautiful China.
The security problem in the use of nuclear energy has attracted worldwide attentions, especially after the Fukushima Nuclear Accident, nuclear safety once again caused great concerns in the global scope. Nuclear radiation has a great threat to human health and ecological environment. Nuclear leakage will cause long-term damage to the environment. Therefore, the safety of nuclear technology has been a key constraint on its further development. For a long time, all countries in the world have done a great deal of research and development work on shielding against nuclear radiation. A series of protective shielding materials have been developed.
Radiation proof materials can effectively reduce the intensity of radiation, prevent radiation pollution, effectively protect human health and ecological environment, and are widely used in military, medical, daily life and energy fields. Among them, radiation proof cement and radiation proof concrete are the most widely used radiation proof materials.
Radiation resistant cement is a kind of special cement which has good shielding effects of X ray, γ ray, fast neutron and thermal neutron. Radiation protection cement can not only effectively protect atomic reactors and accelerators in nuclear power station, but also be widely used in the solidification treatment of nuclear waste, which has good shielding and protection effects on nuclear radiation. However, the recent application and research works on radiation proof cement at home and abroad are mainly barium cement, strontium cement and boron cement. Barium cement has certain shielding effects on X ray and γ ray, but it has high calcination temperature and poor thermal stability, which is only suitable for low temperature environment. Boron cement has better absorption and shielding performance for neutron ray, but it has the disadvantages of high energy consumption and poor thermal stability, and it is easy to cause expansion of cement and cracking of concrete. Although there are many kinds of radiation proof cement, with many problems such as single radiation proof effect, high energy consumption and poor thermal stability etc.
“The New Multiple Shielding Radiation Proof Concrete” developed by Hubei University Tianshu IRDI is support by National Natural Science Foundation of China - New Radiation Proof Structure Coordination and Performance Research on Multiple Shielding (No. 21241007), National Natural Science Foundation of Hubei Province - Key Technology for Preparation of Radiation Proof High Cementitious Cement (No. 2001CDA009). Aiming at the existing problems in applications of radiation proof concrete, Hubei University Tianshu IRDI has developed a new multiple shielding radiation proof cement has good shielding effects on X ray, γ ray and neutron ray with stable performance, strong durability, wide application environment after years of researches, developments and tests. And we have won many related invention patents.
The research contents include several aspects:
1) The determination of solid solubility of radiation proof ions in cement clinker, according to the coordination chemistry and computational chemistry theory, combined with XPS, EPR, XRD, EBSD and other testing methods, to analysis of solid solution pattern and solid solution limit of radiation proof ions in mineral phase crystal structure in cement clinker of, and determine the reasonable content range of radiation proof element.
2) Preparation of new radiation proof cement clinker, optimize the mix proportion design, according to the intrinsic links among phase transformation, the changes of grain size and properties under different temperature conditions, determine the best thermal regulation and prepare the new radiation proof cement clinker.
3) Research on microstructure of the new radiation proof cement, analyze the microstructure model of cement to investigate location of radiation ions in crystal structure, study microstructure and performances of cement specimen before and after irradiation, reveal the change regularity of microstructure and its radiation proof effect.
4) Preparation of radiation proof cement by clinker and special mixing materials, use high efficient and energy saving cement grinding process, select special mixing materials with a lattice space capacity such as rectorite, zeolite, attapulgite and radiation proof clinker for grinding, to produce multiple shielding radiation proof cement.
At present, the new multiple shielding radiation proof cement has won many national patents and reached the expected goal:
l）Effectively control the particles distribution of radiation proof cement:
Particle (< 32 μm) content: 79.33%.
Particle (32 μm ~ 64 μm) content: 17.69%.
Particle (> 85 μm) content: 0%.
2）Greatly improve the water reducing rate.
3）Physical properties of radiation proof cement meet the relevant radiation protection requirements of Chinese GB175 standards.
4）It can be used in construction, which can shield γ ray, X ray, and various neutron flow with shielding efficiency more than 99%, without increasing the thickness of the building.
Through performance tests on various rays, we have authority inspection reports issued by the Institute of Nuclear Physics and Chemistry, and China National Key Laboratory of Nuclear Data, which proves that the new multiple shielding radiation proof cement has excellent performances on a variety of rays.
The new multiple shielding radiation proof cement researched and developed by Hubei University Tianshu IRDI has comprehensive shielding effects, stable performances, strong durability and wide application environment. It can be widely used in nuclear power projects, effectively guarantee the safe use of nuclear power, safety and sustainable development of nuclear power companies, effectively alleviate the energy crisis and environment pollution in China, contribute to the adjustment of energy structure and change the economic development mode, promote social harmony and healthy development, which has important social and environmental benefits.