High density radiation shielding concrete is produced by blending heavy weight aggregate, cement, water, and special additives. Applications of radiation shielding concrete is discussed.
Aggregates for high density concrete for radiation shielding are iron shot and steel punching which are utilized to produce substantially high dense concrete. Other types of heavy weight aggregates that are used to produce medium to low density concrete are barite, magnetite, limonite, goethite, and ilmenite.
There are number of additives that added to high density radiation shielding concrete to enhance the shielding property of the concrete. Examples of additives are boron frits, borocalcite, and colemanite.
The high-density radiation shielding concrete have different but specific applications which will be discussed in the following sections.
Fig.1: High Density Radiation Shielding Concrete Blocks
Applications of High Density Radiation Shielding Concrete
Following are the applications of radiation shielding high density concrete which are discussed:
- In nuclear industry
- Other Application
Application of High Density Radiation Shielding Concrete in Nuclear Industry
The major utilization of high density radiation shielding concrete is in the nuclear industry. Different radiations are released in power production plants and facilities in which nuclear material is processed again, and in this situation the role of this type of concrete is came to play and it offers biological protection against all types of detrimental radiations.
Figure-2 and Figure-3 shows nuclear generator power plant and nuclear reprocessing facility respectively in which biological shielding is needed.
Fig.2: Nuclear Power Generation Plant
Fig.3: Tokai Reprocessing Facility in Tokai, Japan
Radiation may be released in several buildings other than nuclear facilities for instance for instance industrial research, universities, and it has numerous utilizations in medical sector for instance linear accelerator which is applied in oncology departments of hospitals.
It is worth mentioning that, the effectiveness of the biological protection provided by high density radiation shielding concrete is not only proportional to the concrete density per unit thickness but also it is affected by concrete chemistry in terms of elemental analysis.
Table-1 provides elemental compositions of two different concrete mixtures. It can be noted from the table that; elemental compositions of each mix design are substantially different. Hence it is extremely crucial to avoid changes by concrete provider in the type of cementitious material without the designer consultation.
Table-1: Element Compositions of Two Typical Concrete Mixtures
|Type of concrete||Standard density concrete containing 50% OPC+ 50% GGBS||Magnetite concrete containing 50% OPC + 50% pulverized fuel ash|
|Typical density||2420 Kg/m3||4000 Kg/m3|
|Mixture proportions by weight|
|Elemental compositions by percent of weight|
|Other minor constituents||2.2||2.5|
Added to that, various radiations for instance neutrons, gamma, and beta rays possess different intensity which might complicate the concrete protection provision.
It is possible that, the natural way of radiation creates substantial amount of neutron. In this situation, a highly-specialized strategy may be needed to provide effective protection.
Therefore, neutrons must be caught to avoid their influences within concrete because it might produce heat in concrete and lead to structural issues and consequently create problems for the biological shield.
To tackle problems related to the nuclear radiation issues, recommendations of nuclear physicist should be considered in this regard. It should be said that, in the construction of nuclear facilities, technologist engineers can considerably help both designers and nuclear physicist to solve practical problems related to biological shielding.
Other Applications of High Density Radiation Shielding Concrete
Except in the nuclear industry, high density radiation shielding concrete used by offshore oil industry as a layer to cover pipelines under the sea and usually magnetite concrete is applied as shown in Figure-4 and Figure-5.
The high-density concrete is employed as a counterweight for instance large amount of high density concrete is placed at the legs of North Sea gravity structure in the United Kingdom for structural stabilization.
Figure-6 shows the legs of North Sea platform in which considerable quantity of high dense concrete were employed.
It may be used as a stabilizer in foundation of bridges where large mass is needed but the area is limited and required mass cannot be achieved by using other types of concrete. Finally, it is applied noticeably in the structures under water.
Fig.4: Mattresses Constructed from Concrete Used to Protect Pipelines Underwater
Fig.5: High Density Concrete Covered Pipelines Underwater
Fig.6: High density Concrete Used in Legs of North Sear Platform for Structural Stabilization