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ASSESSMENT OF RADIATION PROTECTIONPRACTICES AMONG INDUSTRIAL RADIOGRAPHY PERSONNEL–(A CASE STUDY OF SAIPEM CONTRACTING NIGERIA LIMITED)

Dept: MEDICAL RADIOGRAPHY AND RADIOLOGICAL SCIENCE File: Word(doc) Chapters: 1-5 Views: 2

Abstract

Reports of high radiation-related accidents have been associated with industrial radiography than in any other radiography sub-specialty, mainly due to breach of radiation protection practices. This study examines the availability and utilization of radiation monitoring devices, the means of environmental protection during field operations and the commonly used radiation sources in Saipem Contracting Nigeria limited (SCNL). A descriptive survey design was adopted and convenience sampling technique was used in selecting both the study company and study sample. The respondents responded to a 32 item structured instrument in form of interview guide containing questions on the availability, utilization, means of environmental protection from radiation as well as commonly used radiation sources. Critical ratio test was performed and used in testing the hypotheses. The findings show that radiation monitoring devices are availableand are utilized during field operations. Findings also show

INTRODUCTION

1.1     BACKGROUND OF STUDY

Industrial radiography uses x-rays and Gamma rays to produce a radiograph of specimen or material, showing any changes in thickness, defect (internal or external), and assembly details, to ensure optimum quality. This application is called Non-destructive testing.

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Three types of radiation sources are typically available for such purposes.

• Radioactive materials that are gamma ray emitters such as Iridium -192 (192Ir), Cesium-137 (137cs) and Cobalt-60 (60Co)
• Neutrons that are produced in reactors or by other means (particle accelerators, Radionuclide) and this application of neutrons is specifically referred to as neutron radiography.
• X-ray tubes that are characteristic of conventional x-ray machines.

Industrial radiography machines which are x-ray tube based can produce dose rates in air of about 2Gy per minutes at one metre. These machines are usually portable or mobile and convenient for use in a wide range of conditions such as at air craft hangers, pipeline construction and deployment, fabrication facilities, offshore platforms operations, bridges or construction sites.  At work sites, the working conditions coupled with frequent manipulation of such high-intensity radiation sources present much potential for radiation exposure to occur. Both the workers and other persons proximal to the work area can be exposed to high radiation fields which, potentially could lead to injuries or death.

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In another industrial application, there are systems specifically designed to focus intense beam of high energy electrons that melt and bond metal under vacuum conditions and these electron-metal interactions can produce x-rays as a by-product of the bonding process. Such systems are called Electron beam welders. Beam current and high voltages are typically in the range of 20-200milliAmpers and 120-450kilovoltage respectively. Consequently, the operations of electrons beam welders present a potential for exposure to x-rays and electrons, which are types of ionizing radiation.

In general, the interaction of ionizing radiation with matter is probabilistic, that is, there may or may not be an interaction. The interaction with individual cells of living organisms may be direct or indirect. At the cellular level, direct interaction with Deoxyribonucleic acid (DNA), or other constituents can cause damages. Various possibilities exist for the fate of cells exposed to ionising radiation.

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1. Damaged cells are completely repaired by the body’s inherent repair mechanisms.
2. Damaged cells die during their attempt to reproduce. Thus tissues and organs in which there is substantial cell loss may become functionally impaired
3. Damaged cells survive the radiation insult, but are misrepaired and are able to undergo subsequent divisions. These cells, with the progression of time may be transformed by external agents (e.g. chemicals, diet, radiation exposure, life style, etc.), and may develop into leukaemia or cancer after some years. Such latent effects being referred to as stochastic. Should germ cells in the ovaries or testes be modified by radiation, hereditary effects may occur in the progeny of the individual exposed to radiation. Exposure of embryo or foetus to ionising radiation could increase the risk of leukaemia in infants and, during certain periods in early pregnancy, may lead to mental retardation and congenital malformation if the amount of radiation is sufficiently high.

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Thus, exposure to ionising radiation has the potential to cause early or late adverse health effect. This is why the radiation risks associated with industrial radiography operations need to be managed. This study is designed to ascertain the radiation protection procedures adopted by Saipem Contracting Nigeria Limited (SCNL)

 

• STATEMENT OF PROBLEMS

• More radiation-related accidents tend to occur in the industrial Radiography application than that in any other radiography application

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  . This may be due to close proximity of the control point to the source or inadequate use of radiation monitoring devices.
• Whether adequate radiation protection practices are carried out in typical industrial radiography outfit in the country becomes very essential bearing in mind the health hazard implication to workers and humans in the environment.

 

1.3     PURPOSE OF STUDY

1.3.1  General Purpose

          To assess radiation protection practices among Non-destructive testing personnel in SAIPEM CONTRACTING NIG LTD (SCNL).

 

1.3.2  Specific Objectives:

• To determine the availability of radiation monitoring devices during field operations.
• To determine the utilization of radiation monitoring devices during field operation.
• To ascertain the means by which the people within the environment are protected against the radiation.
• To find out the commonly used types of radiation sources in industrial operations in SAIPEM CONTRACTING NIG LTD.
• To determine the operator- source barrier distance during field operations.

1.4     SIGNIFICANCE OF STUDY

• This work will provide standards of radiation protection for People without unduly limiting the benefits of practices giving rise to exposure.
• This work will prevent the occurrence of deterministic effects in individuals by keeping doses below the relevant threshold and to ensure that all reasonable steps are taken to reduce occurrence of stochastic effects in the population at present and in the future.

 

Hypothesis one

H

o:    

The rate of utilization of radiation monitoring devices is independent of the gender of the radiation workers in SCNL.

 

Hypothesis two

H

o:        

The rate of utilization of radiation monitoring devices during field operations is independent of the level of education of workers in SCNL.

Hypothesis three

H

o

 The rate of utilization of radiation monitoring devices during field operations is independent of the basic profession of the radiation workers in SCNL.

 

Hypothesis four

H

o

      The rate of utilization of radiation monitoring devices during field operations is independent of the duration of radiation workers’ duration of practice.

 

1.5     SCOPE OF STUDY

This study related to all types of industrial radiography equipment and facilities in SAIPEM CONTRACTING NIG LTD in Port-harcourt, River state. It covered radiation protection and safety procedures in Saipem Contracting Nig. Ltd, and lasted for a period of three months.

 

OPERATIONAL DEFINITION OF TERMS

ALPHA RADIATION:A particulate form of nuclear radiation that consists of a helium nucleus without its electrons. An alpha particle has a charge of +2 and can travel only short distances.

APPARATUS FOR GAMMA RADIOGRAPHY:Means an apparatus, including its exposure container and accessories, designed to enable gamma radiation emitted by a sealed source to be used for industrial radiography.

BETA RADIATION:A particulate form of nuclear radiation that consists of anelectron. A beta particle has a charge of -1 and can travel millimeters to centimeters in tissue.

CALIBRATED:Means an instrument, component or system that has undergone the measurement of, or adjustment to, to ensure its accuracy or response is acceptable and the processes are performed by an agency recognized and approved by the appropriate authority;

COLLIMATOR: Means a device to limit a useful beam to the required cross-sectional area of interest.

CONTAMINATION:The presence of unconfined radioactive material on orwithin any object where it is not desired.

CONTROLLED AREA: Means any area in which specific protection measures and safety provisions are or could be required for controlling normal exposures or preventing the spread of contamination during normal working condition, and preventing or limiting the extent of potential.

DETERMINISTIC EFFECT:An effect in which the severity of the symptoms are related to the dose of radiation. Example: Acute Radiation Syndrome.

DOSE:A calculated measurement of the amount of energy imparted by ionizing radiation. Dose is relative to the size of the source, the radionuclide or radiation machine involved, and the length of time and circumstances of the exposure.

DOSIMETRY:Devices that measure accumulated, individual dose. These devices are usually worn by workers who handle radioactive materials or work in areas where radiation is present.

EXPOSURE:The irradiation of any object.

exposure container” means a shield in the form of a container designed to allowcontrolled use of gamma radiation and employing one or more sealed sources;

FULLY ENCLOSED SITES: An enclosed site such as a shielded room, the boundary of which is formed wholly by suitably designed physical barriers and access is controlled by physical barriers.

GAMMA RADIATION:A form of electromagnetic radiation that is nuclear inorigin. It can travel many centimeters in tissue.

GRAY (GY):The Systems International (SI) unit of absorbed dose, equivalent to100 rads or 1 joule per kilogram.

HALF-VALUE-LAYER (HVL):Means thickness of a certain material required toreduce radiation of a known energy range and intensity, to half of its originalintensity. This can also be expressed as the quotient of 0.693 by the linearattenuation coefficient of the material;

INDUSTRIAL RADIOGRAPHY: a non-destructive technique of examining structure of materials utilizing x-rays, neutron or gamma rays.

LEAKAGE RADIATION: means all radiation emitted from the exposure container or x-ray tube housing other than the useful beam;

RAD:An acronym standing for Radiation Absorbed Dose. An exposure of one rad results in the absorption of 100 ergs of energy per gram of tissue exposed.

RADIOGRAPHIC EQUIPMENT: Includes x-ray equipment for industrial radiography,apparatus for gamma radiography and pipeline crawler equipment.

SOURCE:Means any material or irradiating apparatus which emits x or gamma radiation suitable for industrial radiography.

SHUTTER:A device fixed to the x-ray tube housing or exposure container capable of intercepting the useful beam.

SOURCE CHANGER: A device designed and used for replacement of sealed source in an exposure container.

STOCHASTIC EFFECT:An effect in which the probability of occurrence is related to the dose of radiation. Examples: genetic defects, cancer.

THERMOLUMINESCENT DOSIMETER (TLD): An extremely accurate device to measure and provide a permanent record of exposure to radiation.

USEFUL BEAM:Means that part of the radiation which passes through the window, aperture, cone or other collimating device of the x-ray tube or exposure container.

X-RADIATION:A form of electromagnetic radiation arising from the electron shells of an atom.