Binding Materials for Biological Shielding
High Hydrated Boron Containing Binding Materials for Biological Shielding from Radioactive Radiation in Industrial and Research Objects
Tech Area / Field
- FIR-MAT/Materials and Materials Conversion/Fission Reactors
- FIR-NSS/Nuclear Safety and Safeguarding/Fission Reactors
3 Approved without Funding
Kutateladze Research Institute of Building Materials of Joint-Stock Company "Saksashenmetsniereba", Georgia, Tbilisi
- Università di Roma "La Sapienza" / Nuclear Engineering Department, Italy, Rome\nUniversity of Florida / College of Engineering/Department of Nuclear and Radiological Engineering, USA, FL, Caipesville\nAgenzia Nazionale per la Protezione dell'Ambiente, Italy, Rome
Project summaryWide use of atomic energy for peaceful purposes (small-sized atomic power plants and industrial plants, water-distillers, atomic power-stations, heat-supply atomic stations, etc.) puts forward resolution of the most complicated problem: biological shielding from mixed neutron and gamma radiation of nuclear industrial and research instalations.
The main purpose of reactor shield is to reduce doses of gamma-radiation and neutrons to ultimate permissible values. Various mixtures of substances mainly containing hydrogen and heavy metals have the best protective properties in regard to efficiency of moderation and absorption of mixed gamma and neutron radiation.
Hydrogen is the most efficient moderator of neutrons, since decrease of neutron energy resulting from one collision is inversely proportional to the mass of particles collided. After neutrons have been moderated to thermal energy values, they are absorbed with high probability by both hydrogen nuclei and nuclei of medium weight and heavy elements.
Hence, it is evident that material of the shield should contain in its composition substances containing hydrogen and heavy elements to reduce output of capturing gamma radiation. In essence, such materials are hydrated and heavy concretes. However, concretes have one essential shortcoming. In the process of use, while absorbing radioactive radiation and also being under the impact of other sources of heating, they heat up to high temperatures (300-400 °C) and in length of time they lose all fixed water. As a result, shielding properties of concrete towards not only neutrons but also capturing gamma radiation considerably deteriorate due to enlargement of migration area of neutrons which have lost water and have been disposed closer to the outer surface of the shield.
It is possible to remove the mentioned shortcoming of concrete by using special high-hydrated boron containing binders able to retain fixed water under high temperatures, instead of commonly used cements (Portland and aluminous ones). Improvement of shielding qualities towards gamma radiation is also possible to reach by using wares on the base of received binding materials by press method. Characteristical feature of press wares compared with wares of plastical form is higher compactness built up, shielding construction absence of radioactive dust during building up.
It is not difficult to produce a binder with high content of water, however its retention in the process of use of the shield is a complicated problem.
At present, production of a special high-hydrated boron containing binder, such that solidified stones made of it can sustain large amount of fixed water under high temperatures and temperature drops without considerable changes of shielding and physical-mechanical properties, is the most urgent problem to be solved, and the submitted project proposes its solution.
It should be noted here that existence of a collaborator proves the fact that there is no duplication in given field; encourages scientific and technical contacts with foreign specialists in our and allied fields; promotes dissemination of information concerning results of the work and developments on the Project on an international scale, as well as long-term collaboration with the scientists who work in this research direction.
By submitting the project concerning development of a special high-hydrated boron containing binder shielding from radioactive radiation, the Institute is based on existing tradition of carrying out research and corresponding personnel in this field that is reflected in more than 20 certificates of authorship of the Soviet Union and a number of publications part of which are listed below:
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