1990 Iraqi Atomic Energy Commission Annual Report

ANNUAL REPORT

1990

IRAQI ATOMIC ENERGY COMMISSION

The days prior to Christmas many people become active in shopping gifts while those involved in editing this annual report get engaged in another kind of activity. They interact with their fellow researchers in reviewing and editing the draft report and then pushing it before deadline to the printer.

The draft was actually finalized in the first few days of January and then was sent to the printers. It was expected the printing would be completed by the end of March. In spite of dark clouds were showing in the horizon warning of coming evil at the time, none of the Iraqi researchers and technicians at the IAEC installations could in anyway imagine how the state whose president lunched the motto " Atoms for Peace" and initiated its programme back in the early 1950's, would undertake a campaign of bombing nuclear installations built in direct response to this motto.

The United States of America, the depositary State for the Treaty on the non-proliferation of nuclear weapons (NPT), has indeed undermined the very system that helped designed, promoted and developed - the safe-guard system for the IAEA - as it destroyed the nuclear installations at the Tuwaitha site.

The U.S.A destroyed the zero-power nuclear reactor, just visited by an IAEA's team of inspectors in November, 1990 under the pretence that Iraq resolved to use it for production of nuclear weapons.. and so forth. The Iraqi researchers believed that no site can they take refuge to, safer than that housing a zero-power reactor and a 5MW reactor - both subject to regular IAEA inspection and both for peacefull uses: radioisotopes for medicine and industry, and student training.

For this reason, these research people collected all their precious instruments and tools as well as their valuable belongings and kept them in these two sites. The 5MW reactor remained operating normally till 2:30 in the morning of January 17, 1991 (Baghdad time); i.e until the black spitefullness started falling from the sky.

There is no man of reason in this world would be able to believe that human beings could produce atom bombs from a zero-power reactor: yet the U.S.A. wished to commemorate Hiroshima and Nagasaki, this time, on the land of Mesopotamia. This reactor, indeed was air-raided several time. Mr. Leonard S. Spector stated in the New York Times (May, 1991) that the principal purpose of air-raiding of the (Iraq) nuclear sites was to destroy its nuclear fuel. This man, who considers himself a respected scientific personality expressed sorrow that the Hiroshima mushroom clouds did not rise over Baghdad due to the fact the nuclear fuel was not destroyed.

In fact there is no crisis called "the Gulf Crisis", but certainly there is "a moral crisis"! Indeed, those who established the cow-boy civilization, as they did previously with their native "American" Indians, longed very much for the annihilation of a nation that offered the civilization to the world.

It seems that history is repeating itself. Babylon discovered Pythagorean theorem indeed.

Hence Pythagoras was indeed the son of the Mesopotamia civilization; who was a pupil in Babylon.

Pythagoras was actually murdered just because he asked a Roman soldier not to step on his geometric circles which he had drawn in the sands.

In ancient time, the conquerors burned Babylon the civilization. And today Bush has done it again and has burned all lands of Mesopotamia, too.

The U.S.A. adopted and promoted falsefully and hypocritically the motto "Atom for Peace"!

Indeed the U.S.A. does not want other nations to enter the age of Planck's Quantum Physics. Certainly the U.S.A. wished that other nations not to be able to read more than Newton's physics, and for this the U.S.A. has bombed the technical Library of the Nuclear Research Centre at the Tuwaitha complex.

" any state that controls Tropical Africa or the Middle East or South India or the Indonessian Islands, also possesses the bodies of millions of low-paid striving workers who are consumed by the conquerors as the enormous of amounts of coal and oil are consumed, in a rate to produce more weapons to control more lands in order to control more labour for the production of more weapons, to control more lands.

This is what George Orwell wrote in reference to the less developed world. Orwell's prediction has become more creditable than it did in the Gulf War.

Bush is wrongly supposing that he can prevent Iraq from acquiring science. We have nothing to rebut him except with the following:

I. The front cover of this report contains a picture of the Iraqi clock presented as a gift to Charlmagne, the French Emperor, about one thousand years before S. W. Hawking's "A brief History of Time" was printed.

II. The backcover contains a picture of a Babylonain clay artifact representing one of Euclid's geometric theorms two thousand years before its discovery by Euclid

III. The extended summaries of research work conducted by Iraqi scientists under the shadow of " the war of starvation" waged by Bush against the Iraqi people - including young, old as well as children, of whom about 1416 died at the end of 1990.

1 - The year 1990 witnessed serious work concerning the site selection stage by IAEC staff and by various local governmental organizations. The work included the following activities:

The above-mentioned activities have been completed and the relevant final reports have been submitted to (NPPP) committee for evaluation.

2 - In addition to the a/m siting activities, the following studies are being carried out:

3 - As planned, all activities of site selection were subjected to continuous, and systematic surveillance by the Quality Assurance Department of the project to achieve the quality needed for the work.

EXTRACTION AND DETERMINATION OF BORON IN URANIUM OXIDES, CONCENTRATES, AND ORES BY FLUOROBORATE ELECTRODE

Most methods used for determination of micro amount of boron in the nuclear, agricultural, and environmental industries are either spectrophotometric or direct potentiometric measurements.

Initial experiments were performed to study the behaviour of orion 93-05 tetrafluoroborate electrode response through the conversion of boron to fluoroborate, as well as the experimental conditions for the quantitative conversion of boric acid to fluoroborate. Effects of borate and fluoride ion concentration on the behaviour of the electrode potential was studied by calibrating the electrode in boric acid, sodium fluoride and sodium fluoride with sodium fluoroborate solutions. Boric acid and fluoride ion ( used as fluoride salt have no effect on tertrafluoroborate formation, but by using fluoride ion as hy- drofluoric acid reacted with boric acid and converted to fluoroborate. 5% HF was sufficient for BF₄ formation for

The results indicate that only the method using hydrofluoric acid gave an excellent results.

A series of boron as boric acid ranged from 0.1 to 10 µg ml^-1 were extracted by 2-ethylhexane-l, 3-diol. The results of the extraction indicate that above 2 µg ml^-1 are quite accurate and the electrode gave a steady response time within 5 to 10 minutes, while high errors were obtained by extraction of boric acid less than 2 µg ml^-1 boron. This error is attributed to unstability and drift of the electrode in measuring boron at very low concentration (< 2 ppm), in order to eliminate such error, sulfuric acid was added after extraction process to behave as a total ionic adjustor.

Few experiments were checked for the possibility of formation of BF₄ by adding hydroflouric acid to the organic layer containing boric acid which was obtained from the extraction process. Also we checked the possibility of the extraction of fluoroborate instead of boric acid by diol. All these experiments gave negative results.

Interferences of UO₂²⁺, MO, W, and Mn and their effects on the extraction process were also studied. Under the above experimental conditions, boron was determined in a few samples of uranium by using a standard additional method.

PREPARATION AND STUDY FOR LIQUID URANIUM ELECTRODES BASED ON DIAMIDE COMPLEXES IN PVC MATRIX MEMBRANE

Ion-selective electrodes (ISEs) based on neutral carrier ligands are well established for alkali, alkaline earth metal cation and for uranyl ion. Uranyl-selective electrodes are based on the basis of synthetic diamide.

The diamides N,N' -diheptyl-N,N'-dimelhyl-4.8-dioxan-decone (diamide I) and N,N'-diheptyl-N,N, 6,6- tetramethyl-4,8-dioxaundecan (diamide II) were synthesized in the laboratory and the products were checked with NMR and infrared spectroscopy.

Several spectrophotometric experiments were performed to study the spectral behaviour of the diamides. The spectra of the diamide I gave two absorption maxima at 245 nm and 415 nm while diamide II gave two absorption maxima at 308 nm and 243 nm.

Extraction of uranyl ion with diamides gave a complex absorbed at 274 nm. From the extraction of a series of uranyl ion with molar ratio ranged from 0.5 to 2.5. This gave an indication that the complex is 1:1. A copper as a divalent ion was used for extraction of diamides.

Calibration curves were constructed for the electrodes based on a membrane prepared from a diamides as sensors and dioctyl phenyl phosphonate as mediator in PVC. A calibrations were performed with 10^-1 M to 10^-6 M UO²CL². The behaviour of the electrodes were improved after soacking the membranes in 10^-1 M UO₂²⁺ ion for 24 h. The linear response for the concentration ranged from 10^-3 M to 10^-5 M and a slope of 28.9 mv/ decade.

The behaviour of the electrode in thorium solution (1 ppm to 1000 ppm) and at pH ranging from 3 to 5.5 was also studied, using internal filling solution [Th(SO₄)₂ThCl₄].

Finally, the study was carried out for the effects of thorium and uranium on electrode response in measuring of uranium and thorium.

STUDY THE EFFECT OF URANIUM ON Al, Mg, Ca, Cr, Cu, Co, Zn, Mn, Ni and Fe USING FLAME ATOMIC ABSORPTION SPECTROMETRY

A number of atomic absorption methods have been reported in literature for the analysis and control of uranium and its impurities.

In the present work, the optimum conditions for the determination of trace imputrities (Ca, Fe, Cr, Mg, Mn, Ni, Al, Co, Cu, and Zn) in uranium compounds of flame atomic absorption method have been investigated.

The effects of different concentrations of uranium on the absorbances of the above ions were studied. The results showed that the depression effect due to uranium on the absorbances of Ca, Fe, Cr, Mg, Mn and Zn increases with increasing uranium concentration and reaches maximum at uranium concentration of 10000, 5000, 3000, 3000, 1000, and 1000 ppm for Ca, Fe, Cr, Mg, Mn and Zn, respectively. On the other hand, uranium exhibited no effect on the absorbances of Cu, Ni, Al, and Co.

Ammonium chloride and lanthanum chloride were used as releasing agents and gave 100% elimination of uranium interferences upon Ca, Fe, Cr, Mg, Mn, and Zn.

The effects of different concentrations of nitric, hydrochloric, perchloric and sulphuric acids on the atomic absorption signals of the above ions in the presence of uranium were also investigated and no effects were observed.

The selectivity shown by crown compounds for many cations and anions has been used for the extraction of electrolytes containing these ions to non aqueous solvents. Other workers have further enhanced the field of application of these compounds with the preparation of a number of resin containing crown compounds of different ring sizes.

The sorption behaviour of Eu(lll) on poly(Dibenzo-18-crown-6) resin (PDB18C6) was examined from different picric acid concentrations at aqueous and methanol solutions. The highest distribution coefficient (D) obtained was at 0.028M picric acid and 60% methanol solution. The assignment of the complex formed between the resin and Eu-picrate was studied using slope analysis method and the results obtained suggest the following complex PC Eu Pi (NO₃)₂.

Kinetic mechanism has been investigated using batch method. The T_1/2 of Eu (III) sorption is about an hour which indicates that the sorption rate is rather slow and an increase in temperature results in higher Eu(lll) uptake. Also the results show that the chemical reaction is the rate controlling step . The activation energy was measured and found to be around 1.18 KJ/mole.

In picrate media the extraction of La, Ce, Nd, Eu, Gd, Tb, and Lu was studied using various crown compounds.

Almost linear relations are obtained between log D vs. logarithm of the dielectric constant of several organic solvents, the separation factors are higher with the polar solvents.

In general the extraction increases with the number of donor atoms. The increments are higher in the case of lighter lanthanides. Although the cavities of 15C5 has comparable size to the lanthanides, the bigger cavities of the 18C6 and 24C8 gave better extraction. This effect may reflect that the lanthanide ions are not included in the crown cavity.

By careful examination of the data it can be noticed that Gd (half filled f orbital) is a turning point for other elements. This may suggest the presence of the double-double effect or the tetrad effect.

Concerning the position of Y along the lanthanide series, it is clear that it behaves similar to Lu with all crown compounds studied. This is not a coincidence, since Y(III) has similar outer shells electronic configuration of 4f 4d¹ 5S² to that of Lu 5f 5d¹ 6s² and similar ion diameter.

Am(III) on the other hand locates outside the series. Am(III) has negligible extraction by various crown compounds.

STUDY ON THE SYSTEM TBP-KEROSENE-HNO₃ VISCOSITY, DENSITY, CONDUCTIVITY AND DIELECTRIC CONSTANT MEASUREMENT

The system TBP-kerosene-HNO₃ was investigated for the concentration of TBP in kerosene 20, 30, 40, 60, 80, and 100% in presence of varying concentration of HNO₃ in the organic solutions. Viscosity, density, dielectric constant and electrical conductivity values of these solutions were measured.

It has been reported that pure TBP is present as a dimer and in dilute organic solutions the monomer exists. Whether in the pure state or in solution, TBP is capable of extracting HNO₃ as undissociated molecules with the possible formation of different species, depending on the acid concentration.

In our work the system TBP-Kerosene-HNO₃ had been studied by following the variation of dielectric constant of the solutions with acid concentration. With the help of the TDR(Time Domain Refledometry) system, it has been possible to measure remarkably high dielectric constant values (>100) especially for pure TBP containing high HNO₃ concentrations . These values have been interpreted in terms of association between TBP molecules.

The variation of viscosity with HNO₃ concentration was followed , where a peak is observed at HNO₃ : TBP of 1:2 ratio and a minimum at 1:1 ratio, corresponding to the formation of the species TBP-H₂O-HNO₃ -TBP and TBP- HNO₃, respectively. At higher acid concentrations (ratio HNO₃:TBP >1) the viscosity value starts to rise again, a behaviour which is more spectacular in solutions containing lower concentrations of TBP. This behaviour may be interpreted in terms of the formation of long chain polymeric species which are formed due to the association between polar phosphoryl groups.

Dielectric constant, conductivity and density values of these solutions increase with acid concentration and in each case a break point is observed at 1:1 HNO₃ : TBP ratio due to the formation of the non-associated complex TBP-HNO₃. This is compatible with the viscosity results where the formation of this complex is indicated by minimum viscosity values.

A CHROMATOGRAPHIC STUDY OF THE GASEOUS PRODUCTS, OBTAINED FROM THE GAMMA RADIOLYSIS OF 30% TBP- KEROSENE- HNO₃ SYSTEM

Tri-n-butyl phosphate (TBP) undergoes degradation, when exposed to heat, acid or ionizing radiation. Among these degradation products are di-n-butyl phosphate, mono-n-butyl phosphate, phosphoric acid, butyl alcohol and many gaseous products like H₂, CH₄, C₂H₄, C₂H₆. For gaseous products, hydrogen was found to be the major one.

In this work gas chromatographic technique was used for the measurement of H₂ and CH₄ yields in gamma irradiated 30%TBP-kerosene-3M HNO₃ and kerosene-SM HNO₃ solutions. Possible mechanism for the formation of H₂ and CH₄ were discussed. The radiation chemical yields of H₂ and CH₄ (G-values) in irradiated solutions were calculated.

The dose-rate has little effect on both G(H₂) and G(CH₄). On the other hand G(H₂) was found to be dose dependant and to lesser extent G(CH₄). In aerated system of gamma irradiated solutions, G-values of H₂ and CH₄ were higher than their corresponding values in deaerated solutions. The effect of the presence of HNO₃ during irradiation on G(H₂) and G(CH₄) was investigated. This was done by measuring G (H₂) and G (CH₄) in irradiated 30% TBP- kerosene and kerosene solutions presaturated with 3M HNO₃. The values of G(H₂) were lower compared with the values of the double phase system, while the values of G(CH₄) were less affected. Finally some qualitative mass spectrometric measurements showed the presence of H₂, CH₄, N₂ and no gases.

DETERMINATION OF Zn, Fe, Ni, Mn, Cr, Cu, Ti, Zr AND Mg, AS ALLOYING ELEMENTS IN ALUMINIUM ALLOYS

A method was developed for the analysis of Zn, Fe, Ni, Mn, Cr, Cu, Ti, Zr and Mg in aluminium alloys.

The ICP technique was applied for such analysis since it has positive characteristics to metal alloys analysis over other techniques. These are simultaneous multielement determination capability, low matrix interference and use of synthetic standards. The method can be used on a routine basis by the aid of a computer programme which is supplied by the manufacturer. The experimental design of this method according to the layout of this computer programme enables the user to eliminate the spectral interferences, the ionization interferences and the nonrandom drift in various experimental parameters, such as, power drift, nebulizer pressure variation and plasma argon flow rate variation. The method also includes the elimination of the error caused by the variation of the viscosity of the analyzed solution. The error caused by this effect was overcome by adding bismuth to the analyzed solution to act as an internal standard.

As a result of this experimental setup a precision and accuracy of less than 1% error can be achieved for the measured elements.

DIFFERENTIAL PULSE POLAROGRAPHIC DETERMINATION OF TITANIUM, VANADIUM AND MOLYBDENUM IN STEEL

Polarography is usefull technique for the determination of many minor elements commonly present in steel and alloys. It is rapid, accurate and relatively free from most of the interferences.

The present paper describes a differential pulse polarographic, DPP, method for the determination of titanium, vanadium and molybdenum which present as minor elements in various types of steels.

A polarographic catalytic method for determination of titanium (IV) in part per billion level has been carried out in a base solution consisting of oxalic acid, sulphuric acid and potassium chlorate. The high sensitivity of the signal offered a good opportunity to apply this methods for analysis of steels. Electrolysis of the samples solution is applied to remove iron and some other constituents that may cause interferences with the DPP procedure. The method allows good accuracy and can be used for routine analysis.

DPP method for the determination of vanadium (V) at trace levels has been established, which is based on electrochemical reduction of vanadate ions in potassium oxalate at pH=5.4 . A linear calibration curve is obtained for vanadium (V) concentration range between 4.5 x10^-5 to 1.5x10^-3M. The method has been applied successfully to the determination of vanadium in steel after removal of bulk iron.

In the chemical processing of low grade uranium ores either acid or carbonate reagents may be used as hixiviants for dissolving the uranium.

For uranium bearing limestones and other high line CaO ores acid consumption would be prohibitive and carbonate circuit must be used. Sodium carbonate is a relatively cheap reagent.

Other reasons for using the carbonate system, the corrosion problems in such a system are negligible compared with those encountered in acid circuits.

The uranium species soluble in carbonate leach solutions is the uranyl tricarbonate ion. The formation of this ion by the solubilization of hexavalent uranium mineral such as carbonate or a quadrivalent uranium mineral such as uranite may be represented by the following reaction

Leaching experiments were carried out in a five litre glass reactor equipped with variable speed mixer and an air bubbler and heating media (water bath).

The particle size, leaching temperature, ore roasting, sodium carbonate and bicarbonate concentrations, oxidizing agent, air quantity, liquid-solid ratio and leaching time parameters were determined.

In conclusion the optimum conditions reached for the studied parameters which give the optimum leachability of uranium from ore, were as follows:

During the past years, the use of ion exchange resins, in particular the anion exchange resins has stimulated much interest for the recovery of uranium from leach solution containing small quantities of uranium (0.1 -5g/l).

The ion-exchange process is based on the ability of anion exchange resins to extract uranium selectively from sulphuric acid or carbonate leach solution . After the uranium is concentrated in the resin, it is displaced by a suitable salt solution to obtain a more highly concentrated, relatively pure uranium liquor.

The ion exchange process involves the ability of hexavalent uranium as the uranyl ion UO₂²⁺ to form anionic complexes with sulphate ion SO₄²⁺ and carbonate ions CO₃^2-.

Two types of resin has been tested, the first Amberlite IRA 400 by Rohm and Hass and the second Dowex-1 by Dow chemicals.

Experiments have revealed that the flow rate range is 0.5-1.0 L/hr cm2, and the retention time is 4-12 min.

The effect of flow rate and retention time on the elution curve has been studied ; the flow rate range is 0.05- 0.1 LYhr.cm2, and the retention time is 10-20 min.

The resin capacity for both types, IRA 400 and Dowex-1 was found to be 15-20 gm/l resin using real leaching solution.

Many elution solutions were tested such as 1M NaCl + 0.1 M HCl and 0.9 M NaNO₃ + 0.1 M HNO₃ .

DETERMINATION OF As, Se AND Hg BY HYDRIDE GENERATION AND COLD VAPOR ATOMIC ABSORPTION SPECTROMETRY

Mercury, arsenic and selenium have been given much attention by many researchers due to their importance in environmental pollution and their applications in many industrial fields.

In the present work, the experimental conditions for the atomic absorption determination of mercury by cold vapor techniques and arsenic and selenium by hydride have been thoroughly studied.

The linear working ranges for Hg, As and Se are (10-40 ppb),(1-4 ppb) and (1-5 ppb), respectively.

The effects of some inorganic acids, namely HCl, HNO₃ and H₂SO₄ on the sensitivities of Hg, As and Se have been investigated. 1% HNO₃, 2% HNO₃ and 1% H₂SO₄, gave the highest absorbances for Hg, As and Se, respectively.

The interference effects of Ag, Bi, Cu, Cr, Co, Cd, Fe, Ga, Mn, Mo, Ni, Pb, Sb, Se, Te, Tl, V, Zn, and As on the sensitivity of Hg, As and Se were also studied. Cd, Fe, Sb, Ca and V were found to enhance absorbance signal of mercury while As, Mo, Tl, Co, Pb, Se, Te, Cu, Ni, Bi and Ag depressed it. On the other hand, in the presence of Zn, Cr, and Mn it is found that no effect has been observed.

Ag, Fe, and Mn interfere in the determination of arsenic due to the signal enhancement, V, Cu, Co, Hg, Mo, Ni, Se, Te and Zn showed a depression effect, while Cr, Bi, Pb and Tl did not interfere. Sb, Te, and V were found to enhance selenium signal.

ANALYSIS OF STEEL STANDARDS BY INDUCTIVELY COUPLED PLASMA - OPTICAL EMISSION SPECTROMETRY

Several samples of certified steel standards have been analysed for alloying elements and trace impurities using the technique of inductively coupled argon plasma - optical emission spectrometry.

The elements determined included, As, Cr, Cu, Mo, S, Sn, Ti, V, W and Ni. The analysed steel standards included, carbon steel, low alloy steel, ferritic stainless steel and austenitic stainless steel. The results obtained are discussed and compared with the certified values.

STUDY THE EFFECT OF URANIUM ON Cd, Bi, Si, AND Sn USING FLAME ATOMIC ABSORPTION SPECTROMETRY

A number of atomic absorption methods have been reported in literature for the analysis and control of uranium and its impurities.

In the present work, the optimum conditions for the determination of trace impurities ( Cd, Bi, Si and Sn) in uranium compounds by flame atomic absorption method have been investigated.

The effects of different concentrations of uranium on the absorption of the above ions were studied. The results showed that the depression effect due to uranium on the absorbance of Bi increases with increasing uranium concentration and reaches maximum at uranium concentration of 10000 ppm. On the other hand uranium enhanced the absorbances of Sn, Si, and Cd and this enhancement increases with increasing uranium concentration and reaches maximum at uranium concentration 20000, 20000, 500 ppm for Sn, Si and Cd respectively.

Ammonium chloride, lanthanum chloride and ammonium thiocynate were used as releasing agents. Among these, ammonium chloride gave 100% elimination of uranium interferences upon Cd, Bi, Si, and Sn.

The effects of different concentrations of nitric, hydrochloric perchloric and sulphuric acids on the atomic absorption signals of the above ions in the presence of uranium were also investigated and no effects were observed.

DETERMINATION OF CARBONATE IN COMMERCIAL URANIUM SALTS USING CARBON DIOXIDE GAS SENSING ELECTRODE

A potentiometric method was used for carbon dioxide determination in samples of various commercial uranium salts using Orion model 92-02 carbon dioxide electrode, which consists of a glass pH sensing electrode coupled with a gas permeable dimethyl silicon rubber polymembrane.

This work was carried out for study the effect of experimental parameters on electrode response and interferences effect on determination of carbon dioxide. Several experiments were done for calibration the electrode in an open and closed system. Excellent results were obtained using a closed system, therefore, a sealed cell with 30 ml capacity was used in this study. Specific electrode parameters were determined using Orion filling solution and various concentrations of sodium bicarbonate ( 10-¹ - 10^-3M) and potassium chloride (0.1- 0.3 M) and a suitable internal filling solution (0.2M NaHCO₃ + 0.3M KCl) was fixed for this study. Also the pH of buffer solution is important to convert all the carbonate species, in solution to CO₂ gas. Therefore, five different pH values (2.1-7.8) were used in this study and the suitable pH was about 4.

The last studied parameter was the effect of temperature and we noticed the optimum temperature was 30 °C, which gives temperature coefficients around 1.4 mV/°C.

After fixing the experimental parameters calibration curves were constructed for carbon dioxide electrode using different types of carbonates salts (Na₂CO₃, Li₂CO₃, CaCO₃, K₂Co3, (NH4)2 CO3, SrCO3, MnSO₄, NiCO₃. All calibrations gave a linear relationship in the concentration range 10^-2 - 10^-4M carbonate and response time less than 1min at 10^-2M carbonate to about 3 min at 10^-4M and slopes range from 51-56mv/decade.

Selectivity in the presence of interfering species (NO_x,SO₂, and H₂S) was studied at different pH (1.6-4.5) and the selectivity coefficient were determined.

Poly (4-vinylpyridine) resin has been prepared by Chemical Synthetic Ltd. and studied for the extraction and separation of metal ions in various solutions.

In the present work a polymer containing 4-VP group has been synthesized to reflect different porosity and pore size distribution . Two of these resins were examined for the extraction of Hg (II) from various solutions. Both resins are of macroporous texture, with pore size 500 °A and 3000 °A, respectively. Their capacity for Hg and the sorption rates are measured . Both resins exhibits more or less the same characteristics for the extraction of Hg(III).

Absorption and elution of Hg were examined by column operation using resin 2. Leakage of Hg was observed when the ratio of effluent volume to bed volume approaches 35.

The elution of Hg absorbed on the column was carried out with 2 molar H₂SO₄ , and 95% of Hg was recovered.

THE INHIBITION OF CARBON STEEL CORROSION BY PHENYLTHIOUREA HCl SOLUSIONS OF DIFFERENT STRENGTHS AT DIFFERENT TEMPERATURES

The corrosion and inhibition of low carbon steel in aerated and deaerated HCl acid by phenylthiourea (PHTY), has been investigated in the temperature range (30-60°C), acid concentration range (1-4 N) and inhibitor concentration range (0.1-1g/l) using a Modified Box-Wilson design for planning the experiments both for two and three variables.

In this investigation, BETACRUNCH computer programme was used lo calculate the corrosion currents and Tafel parameters from low polarization data (i.e. the corroded specimen was polarized at small ± Δ E from the corrosion potential).

The corrosion rate in deaerated HCl acid as a function of temperature was found to follow Arrhenius equation, and that corrosion rate increases exponentially with acid concentration and also according to conventional kinetic equation.

Also it was found that the second-order regression analysis of the objective function (corrosion rate) using multivariable least squares programme, led to the following equations for two variables experiments (temperature and acid concentration):

These equations adequately describe the corrosion behaviour of carbon steel in the HCl acid throughout the region studied.

PHTU was a very powerful inhibitor and its influence on the corrosion of carbon steel in aerated and deaerated HCl acid solutions was found to be mixed, affecting both of the partial anodic and cathodic reactions.

Corrosion potentials obtained from polarization curves were shifted to more negative values compared with the acid only in the presence of PHTU, i.e., polarization of the cathodic reaction being more prevailing.

Corrosion rates increased with increasing temperature and acid concentration both in absence and presence of PHTU. Finally it was found that PHTU slightly more efficient in aerated than in deaerated HCl acid solutions.

Schemes to prepare a polymer containing oxine(8-hydroxy-quinoline) as a chelating group have been proposed by a number of authors. A method was proposed for the preparation of a condensating polymer of high water regain and ion exchange capacity ; these have reflected a rapid exchange rate.

In the present work Microporous polystyrene resin containing the oxine group, whose structures are distinct from the types mentioned above is proposed and their properties are described . Emphasis is laid on the effect of resin texture on the ion exchange and sorption rate of the resin for Cu, Fe, Zn, and Hg.

Two polymers of the styrene-DVB were prepared using different porogen, one of them (resin No.1) has pores of mean size (510 °A), the other (resin No.2) 3100°A. Both polymers were examined for the extraction and sorption kinetic of some metal ions from various solutions. There was no significant difference in the value of ion exchange capacity of either resin. A Higher sorption rate is, however, observed with resin 2. It is attributed to the greater pore size and consequent reduction in hinderence in resin 2.

SEPARATION AND PRELIMINARY ASSESSMENT OF ORGANIC MATERIALS IN CARBONATE ORES

Organic constituents in ores play an adverse role in any metal isolation process. Their removal is therefore essential . The removal entails, at least, some knowledge of the identity of the organic materials involved. The separation methods tested in this work involved:

a. roasting of ore between 250-900°C. We found that heating at about 300°C leads to loss of the major part of the organic material.

b. addition of various amounts of MgO, KMnO₄, leads to an extraction of around 20-30% of the organic material.

c. about 50% of the organic material can be removed by passage of a stream of ozone in the ore solution.

d. more efficient separation has been achieved using columns of activated charcoal or ion exchange resin XAD-4. The former being more efficient than either the resin or the ozone.

2- Separation and quantitative assessment of organic constituents. The methods employed in constituent identification and separation efficiency assessment include spectrophotometry, gas chromatography and mass spectrometry. In spectrophotometry, organic materials with an absorption peak at 230 nm, and height varying with organic constituent content has been observed. This peak has been used in both qualitative and quantitative studies.

Gas chromatography has yielded three peaks with retention time of 0.41,5.05 and 5.88 minutes respectively. All of these peaks have been utilized in organic constituents assessments.

Mass spectrometry studies have shown the presence of a number of peaks between mass units 51 and 91; peak heights also varying with constituents amounts.

a. solvent extraction with Dodecane, CCl₄, CHCl₃, CH₂ Cl₂ with Dodecane proving the more efficient.

b. separation on the resin XAD-4 at pH1 .5 (with H₂SO₄) and 1M NaOH as eluant. Retention on the resin was 90-100%, while the elution was 100%. The procedure involves extensive pretreatment of the resin XAD-4.

c. the use of the polymer Amberlite (IRA093) for the isolation of the organic materials does not require any special pretreatment. The adsorption efficiency of this resin is 100%. This method can be accepted as a reliable analytical procedure.

Organic constituents identification can be sugested using GC-MS for a future work.

A SELECTED ANALYTICAL METHOD FOR THE DETERMINATION OF ZIRONIUM AND FLUORIDE IN PICKLING SOLUTION

In order to obtain an outer surface clear from any dirts or scratches, a pickling solution (3.5%HF, 39% HNO₃, distilled water) is recommended for the treatment of fuel rods made of zircalloy which helps to remove the external surface as H₂ZrOF₄ chemical form, there is a white crystalline precipitate, slowly soluble in acid and insoluble in basic or neutral solution. The outer surface after treatment is mainly ZrO₂.

The efficiency of pickling solution depends mainly on the remaining hydrofluoric acid and Zr concentration. Gravimetric precipitation and spectrophotometry methods are used to determine zirconium concentration in pickling solution.

It was found that if HF is depleted the etch rate will slow down, so the depleted and weak etch bath can be brought back to the proper strength by further addition of HF. Date are obtained by weighing method, contrast weight loss as a function of time at different stages showing that when the etching time is longer the weight loss will be more appreciable and HF activity will drop down. Weight are measured accuratly, the difference indicates the extent of weight loss as H₂ZrOF₄.

The effect of alloying elements concentration with Zr is too small to be considered (less than 2%) zirconium is precipitated as Zirconium mandeac acid, a stable chelating compound Zr(C₈H₇O₃)₄ with small amount of Zr(10 mg or less) the precipitate may be washed with its saturated solution, acetone, dried at 100-130°C and weighted.

The accurate result, ignition to the oxide is recommend. Anions which complex Zr such as fluoride, nitrate, sulphate cause incomplete precipitation . Alizarin red-s is a suitable reagent for zirconium in pickling solution ranged 1-1000 g and measured at 540 nm Decolorized complex form caused by fluoride and nitrate as (ZrF₆)^2- is observed. X-ray fluorescences is a selected spectrochemical analysis technique to determine zirconium in pickling where it is considered as a non-destructive method.

Liquids are regarded as the ideal sample beacause they are homogenous. Comparison standards and calibration curves are most readily prepared. Most liquids possess lower x-ray radiation than solids and powers, therefore cells should be deep enough to approximate an infinity thick layer. Several samples and standards of pickling solution have been measured with respect to different etching time.

The accuracy of data obtained by this technique makes it adequate for quantitative analysis.

This work has involved the synthesis and characterization of a number of uranium (IV) tetrachloride and tetrathiocyanate complexes with acid hydrazides. The work has also involved the synthesis and study of some dioxouranium (VI) chloride, thiocyanate and nitrate complexes with the same ligands. The acid hydrazides used as ligands to prepare (43) new complexes are:

acetyle hydrazine (AH), 2-fluoryl hydrazine(FH) and benzoyl hydrazine(BH), 2- piocolinoyl hydrazine (PH), nicotineyl hydrazine (NH), isonicotinoyl hydrazine(INH), 2- thiophene carboxylic acid hydrazide (TH), anthranlic acid hydrazine(ANH), salicyloyl hydrazine (SH):

The prepared complexes have been characterized by elemental analysis, molar conductance, infrared spectra and visible spectrea . The decomposition temperature of these complexes has been measured. Measurements of molar conductivity in non-aqueous medium such as nitrobenzene and tetrahydrofuran indicate that the complexes are neutral whereas in ethanol and dimethyl formamide they correspond to 1:2 and 1:3 electrolytes. The visible spectra (400-900 mm) of uranium (IV) tetrachloride complexes in dimethyl formamide, ethanol and those of uranium (IV) tetrathiocyanate in tetrahydroufuan and methyl cyanide are similar to the spectra of high coordination number (6) uranium (IV) complexes.

Infrared spectra indicate that the thiocyanate group are N-bounded in all uranium (IV) and dioxouranium (VI) thiocyanate complexes and the nitrate groups are monodentate in all dioxouranium (VI) nitrate complexes except for the complex UO₂ (NO₃)₂. 2SH. C₂H₅OH, they act as bidentate.

The infrared spectral studies suggest that all acidhydrazides used in this work act as monodentate ligands coordinating through the carbonyl group oxygen except for the ligands BH,PH in the complexes UO₂(NCS)₂ . 2L, L=BH, pH and UO₂CL₂ . 2PH they act as bidentate ligands coordinating via the carbonyle group oxygen and the terminal amonia group nitrogen.

POLAROGRAPHIC STUDIES OF ELECTROCHEMICAL BEHAVIOUR OF TECHNETIUM IN AQUEOUS SOLUTION

The selected electrochemical behaviour of technetium was studied in aqueous solutions from the most stable species, pertechnetate (TcO₄-), while other species (in a simple forms of technetium) in lower oxidation state are unstable in solid state or in solution.

Pertechnetate exhibits a well-defined polarographic signal in neutral media (KCl, KNO₃ and NH₄CL at pH 6) and also in alkaline media (NH₃/NH₄Cl at pH = 9.2 and in NaOH at pH=13). The half -wave/peak potential was observed at potential close to -0.8V. In such media, pertechnetate reduced to technetium (IV) and the "n" values calculated from Ilkovic equation. No precise change in half-wave/peak potential was observed during the course of changing pertechnetate concentration nor during the change of solution acidity down to pH=4.2.

The polarographic behaviour of pertechnetate varied in a complex fashion with changing the pH of the solution down to ≤ 4.1.

The signal at -0.8V (called A) diminishing gradually, when the pH reach 4.1 and disappear completely at pH ≤ 3.2. The reduction processes of the new appearance singals (called B,C and D), positions, and the sensitivity were examined carefully in base solutions of KCl and NH₄Cl (pH between 4.1 to 2) and the ovall observations were discussed.

STUDY OF MIXING OF ION EXCHANGE RESINS WITH BITUMEN USED FOR THE SOLIDIFICATION PROCESS

The conversion of radioactive spent ion exchange resins into immobile forms to permit their safe disposal out of the human environment has become an increasingly important problem, on account of the accelerating pase of their generation, in keeping with the rising output of nuclear power plants. For the treatment of spent resins, it is at present considered adequate to solidify them in cement or polyethlene, or to incinerate them. It is known, however, that cement products are liable to cracks and break. Moreover, cement offers little advantage in respect to reduction in waste volume.

As for the burning, the current incineration equipment only produces carbonization without true combustion and for incorporating in polymers, the cost of the method is significantly high compared with the above methods. In view of the circumstances, trial experimentals were conducted in incorporating used up ion exchange resins into bitumen to obtain a good solidified waste product.

Laboratory experiments were undertaken on the incorporation into two kinds of bitumen (M40/50, 30/40) of spent ion exchange resins (anion, cation) before and after crashing, in dry and wet forms. The products thus prepared were examined for the properties considered important for radioactive waste management. The items chosen for testing were penetration, ductility, softening point, flush point and water content.

1. penetration, ductility and flush point of all samples were decreased by increasing the percentage of ion exchange resins in both kinds of bitumen, while the softening point was increased.

2. The kind of the ion of the resins affects the physical properties of the final products. So it was observed that the softening point of all samples was more increased by cation resins than the anion.

3. The effect of crushed resins on the increasing of the softening point of the samples was more than the incrushed resins.

4. There was no effect of wet or dry forms of the resins on the water content of the final products.

6. The presence of sodium nitrate in the mixtures loaded to decrease the percentage of the ion exchange resins.

In the present work, the optimum conditions for the analysis of antimony, bismuth and tin by hydride generation atomic absorption spectrometry have been investigated in order to optimise the conditions for their determinations

The effects of several mineral acids namely, HCl, HNO₃ and H₂SO₄ on the sensitivities of Sb, Sn and Bi were studied.

The results showed that nitric acid at 1% concentration gave the highest absorbance value for Sn, while hydrochloric acid at 0.5% concentration gave the high- est absorbance value for Bi.

The interference effects of Ag, Bi, Cu, Cr, Co, Cd, Fe, Ca, Hg, Mn, Mo, Ni,Pb, Sb, Se, Te, Ti and V on the absorbances of Sb, Sn and Bi were also studied and most of them were found to interfere with Sb, Sn, and Bi. In an attempt to solve this problem, many chelating agents such as ethylenediamine tetra acetic acid (disodium salt), ammonium pyrolidine dithiocarbamate and hydroxyl amine hydrochloride have been tried. Among these chelating agents, hydroxyl amine hydro- chloride gave 100% elimination of the interferences due to Sb, Mh, Ti, As and Ag.

The optimum condition for the analysis of samarium by both flame and flameless atomic absorption have been investigated. The Charring-atomization curves for Sm from both pyro-coated graphite tubes and tantalum coated- tubes were selected from these curves.

The effects of several inorganic acids on the sen-sitivity of Sm in nitrous oxide acetylene flame have been studied. The results showed that the depression effects due to HNO₃, HCLO₄, HCL, H₂SO₄ and H₃PO₄ on the absorbance of samarium increases with increasing acid concentration and reach maximum at 4% acid and then levelling off at higher concentrations.

In graphite furnace the effects of acids are cosistent for Sm. The interferences associated with the Sm both in flame and graphite furance were also studied. In flame method, Na, U, Gd, Na, Cs, and Sr were found to enhance the signal of Sm while Zr showed no effect.

In graphite furnace the effects of these ions were inconsistant. However, the use of tantalum carbide coated tube eliminated the effects of Zr, Nd, Gd, and U on Sm absorbance.

CHROMATOGRAPHIC STUDIES ON DIBUTYL PHOSPHATE IN ORDER TO RELATE CONCENTRATION TO BOTH PEAK WIDTH AND RETENTION TIME

In GLC the sample is separated by passing it in the gas phase through a tube packed with an inert powder on which the stationary phase is coated. The carrier gas is passed through the column and the separation is accomplished by a partition process.

Many methods have been applied for the determination of DBP but there were no serious trials to find the most suitable conditions for the analysis of DBP. From the data of a previous work the most suitable conditions for the analysis of DBP were found to be the use of a polar stationary phase of relatively high loading. The widths of DBP peaks were measured over the range (0.005-1M). The equations(where n-no. of theoretical plates, C=concentration and A1,Ao= constants)

(where C=concentration, A₁, A₃ = constants. A₂ = retention time.) were tested for the data under consideration, the second equation was found to deviate over low concentrations and applies fairly well over higher concentrations.

The quality control and internal consistency of results obtained from analysis of water samples are evaluated by monitoring four ratios:

The decision to reanalyze a sample for one or more chemical constituents is based on these four ratios.

The object of the analysis of water sample in our laboratories was to determine the amounts present of

four major cations, Ca²⁺, Mg²⁺, Ca²⁺ and K⁺ and the anions, Cl^-, NO3^-, PO₄^3-, SO₄^2-, CO₃^2-, HCO^-₃ as

well as pH, conductivity, acidity, alkalinity, TDS, TSS, total hardness and turbidity in the samples.

This involves the use of titrimetric, turbidimetric,colourimetric and atomic absorption.

The samples were collected from Dyala and Tigris rivers at a distance of two kilometers from the water supply station of IAEC. In addition to the samples collected from the water supply station and waste water of IAEC. These samples were analyzed twice a month.

Only the waste water samples gave a high values especially the conductivity, TDS, sulfate and cations comparing with the tap water and other samples.

A POTENTIOMETRIC STUDY FOR URANIUM REACTION WITH CARBONATE AND AMMONIA USING GAS SENSING ELECTRODES

The analytical applications of gas-sensing electrodes have been recently discussed. This work was carried out to obtain the optimum experimental conditions for the determination of carbon dioxide and ammonia in uranium salts, ammonium diuranate (ADU) and ammonium uranyl-carbonate(AUC). Gas sensing probes was used for such determination and the effects of the interfering anions and cations were obtained. The rate of decomposition and formation of these salts were also determined.

By using a buffer of 10M NaOH for ammonia determination in ADU and AUC, a slow static response time was obtained and a decrease in the electrode potential was observed.

A yellow precipitate accumulated on the membrane from the inside of the electrode which blocks the holes of the membrane. Different concentration of buffer ranged from 0.05-2M NaOH were used and a good results were obtained for 0.5M for ADU and 0.05 M for AUC.

An excellent results were obtained for carbon dioxide with citrate buffer and hydrochloric acid at pH=2.

Several proposed procedures were tested for sample treatment and the results of ammonia percentage were calculated. Direct addition of a buffer to the sample is virtually in a good agreement with the theoretical values.

The work was carried out to study the effect of some anions (Cl^-, SO_4^2- and NO₃^-) and cations (Mg²⁺,

Ca²⁺ and Ni²⁺ ) on the response of the electrode. The concentration of interfering ions ranged from 10^-3 M to 5x10^-2M.

Large interference is due to Cl^-, NO^-₃ and SO^2-₄. which came from the uranyl salts.

Finally a standard addition method was used for determination of %NH₃ and %CO₂ and the results were comparable with those obtained from the calibration curve.

RISK ANALYSIS DUE TO THE RELEASE OF RADIONUCLIDE FROM THE NUCLEAR REACTORS AT TUWAITHA SITE

Maximum air concentration at ground level, dose equivalents population doses and risk associated with them were estimated for an area with a radius of 15 km centred around Tuwaitha site. The source term was defined in a previous study and the population distribution was done according to 1977 census information. Atmospheric dispertion calculations were based on 1987 data obtained from Baghdad Meteorological Station. The computer code MMAT was used to classify the atmosphere and to provide other input parameters for disper- sion calculation which were used as meteorological input for computer code AIRDOS - EPA.

The highest air concentration was 6.66 x 10^-7 Bq / cm³ in the eastern direction (E) which had resulted in a dose equivalent of 7.0 x 10^-7 Sv / Y and a population dose of 9.86 x 10^-2 man. Sv which were mainly due to exposure to Argon - 41. According to these results, no cancer death case could be expected, even if we extrapolate to one million persons in 30 years, there would be a 0.3 chance of having a cancer death case due to this exposure. Thus, the operation of the IRT - 5000 and Tammuz -2 nuclear reactors had negligible effects on the population and the environment.

The assessment of radiation doses to the puplic from sources of natural radiation is of vital importance because natural radiation is the largest contributor to public collective doses.

Ambient gamma activity measurements were carried out around Tuwaitha site and in some regions in Iraq. An ionization chamber (RSS111 environmental monitoring system) and two portable scintillation counters (SPP - 2 - NF scintillometer and BGS - ISL scintillation counter, Scintex Limited, Canada) were used. The instruments were calibrated with certified sources (Amersham, England), Monthly exposure rate measurements carried out around Tuwaitha site had not indicated an increase in any of the 48 measurement locations.

Exposure rate measurements throughout Iraq had indicated that the highest exposure rate was 9.3 µR / hr in Dhook governorate, the lowest was 6.4 µR / hr in kerbella governorate. Similar results were reported for other regions of the world which were considered of a normal background.

The meteorological data, which were provided by the 54 m tower system (meteostation T1) and the automatic station (T2) have been used to perform the meteorological programme at Tuwaitha site. The purpose of this programme was to support the environmental monitoring programme around Tuwaitha site.

These data included wind speed and direction, air temperature, relative humidity, precipitation, atmospheric pressure, solar duration, and radiation intensity (direct and reflected).

Data analysis showed that the north - westerly winds are prevailed, with noticeable south - easterly sharing at winter season. The stable stratification and unstable conditions are prevailed at night and day times, respectively, around T1, while the neutral weather prevailed over the year around T2. This discrepancy may be mainly due to the obstacles around T1. Therefore the location of the ground level emission sources should be considered in meteorological data selection for diffusion calculations.

ASSESSMENT OF THE TRANSFER FACTORS FROM SOIL TO PLANT FOR SOME RADIONUCLIDES

Transfer factors to predeict the environmental transport of radionuclides through terrestrial foodchains (soil to plant) were derived from field and laboratory measurements. Ambient gamma activity measurements with an RSS-111 environmental monitoring system were carried out in the northern part of Iraq in order to define areas with high background radioactivity. Two main stations were selected, one in Dhook governorate and the other in Nineveh. The exposure rates for those two regions were 10.1 and 9.5 µR /hr, respectively which is higher than the normal background value (about 7.0 µR/hr).

Transfer factor = (Bq of radionuclide in fresh plant sample (1 kg)) / (Bq of the same radionuclide in dry soil (1 kg))

The highest transfer factor was 0.101 representing soil to chick-pea transfer factor. The lowest was 0.0265 from soil to wheat. Similar values are reported in the literature.

Data for transfer factor are normally used in the prediction of radiation doses due to the operation of nuclear facilities. Since it is recommended to use site specific data whenever it is possible for such prediction, then these data will be used in the food-chain models instead of the default values which are non-specific.

The deposited radionuclides on the earth surface can result in a dose commitments to the population and subsequent possible harmfull effects to man. To assess these possible hazards, an environmental surveillance programme was conducted covering most parts of the country that has population density. The programme included ambient gamma activity measurements using portable ultra sensitive gamma ray detector (Types: RSS-111, SRAT, SCINTREX) and various environmental samples measurements. Environmental samples such as soil, vegetables, fruits, grass and fish were collected from selected parts of the country and brought into laboratory for radioactivity measurement and analysis. Nuclides concentrations were determined by direct gamma spectroscopy using a (1.7 KeV) energy resolution Ge (Li) detector with peak detection efficiency at 0.662 MeV of (20%). The system's detection limit for Cs-137 and Cs-134 was 0.5 Bq/kg. Beta emitting radionuclides determination was accomplished after radiochemical separation procedures. The highest activity concentration levels were found in soil samples for Cs-137 . The in situ gamma ray field measurements and different sample's measurements proved no significant rise from background due to nuclear fallout.

ASSESSMENT OF POPULATION DOSES DUE TO THE ASSUMED RELEASE OF RADIONUCLIDES TO THE ATMOSPHERE FROM A NUCLEAR POWER PLANT UNDER NORMAL OPERATION AND ACCIDENTS

Radioecological studies concerning the assessment of population doses due to the release of radionuclides from the VVER nuclear power plant to the atmosphere were carried out according to the criteria proposed in the agreement with the USSR and the approval of the IAEA experts.

The source term for the normal operation and accidental conditions were given by the Soviet experts.

Atmospheric disperssion calculation was based on a Pasquill-Gifford method, food chain models were based on the U.S. Nuclear Regulatory Commission Guides, and dosimetric models were based on the ICRP recommendations.

Ambient gamma activity measurements around the four potential sites, Al-Mahzam, AI-Abasia, Abu-Dalaf and Baiji has indicated that the average exposure rate 1 m above the ground was 7.0 - 7.8 µR/hr which has indicated that all sites are located in area with a normai background radiation.

Gamma spectrometric analysis of environmental samples such as soil, ground water and cantaloupe have indicated the presence of Cs-137 in soil samples, the highest concentration was 18.0 Bq/kg and the lowest was less than 1 Bq/kg.

ASSESSMENT OF RADIATION DOSES DUE TO THE RELEASE OF RADIONUCLIDES TO THE AQUATIC SYSTEM DURING NORMAL OPERATION AND ACCIDENTS

Radioactive materials in aqueous effluents may be released from nuclear power stations either routinely or accidently, into a variety of receiving surface water bodies including non-tidal rivers.

Radiation exposure of humans in the environment of such plant has to be anticipated. In order to determine the total dose to the whole body and of certain organs; the contribution of all relevant radionuclides via the exposure pathways have to be summed for the number of the critical groups of the population.

The assessment pf population doses due to the release of liquid radiocative effluent from the VVER nuclear power plant to Tigris river was carried out according to the criteria that was agreed on with the Soviet and the approval of the IAEA experts. The source term was ex- trapolated from the phase 1 siting study. Dilution factor determination was based on the degree of sectional mixing which classify the river into three approximate regions. The implemented radiological exposure models were based on US NRC methodolgy.

Land and water used were based on information obtained from different governmental agencies and veri- fied by field surveys. Demographic data were obtained from census of 1987.

Activity concentration of radionunclides in groundwater was measured with a gamma spectrometric system. No activity could be detected.

The diffusion of the elements, released from the power plant into the atomsphere and the safety analysis report are related to the aerological parameters in the planetary boundary layer (PBL). This layer can be defined as the layer of the lower atmosphere whose characteristics are directly influenced by the ground surface. For the purpose of providing these parameters at the region proposed for the Nuclear Power Plant (NPP), the following works have been performed :

1. Elaboration of aerological working programme and procedures related to the second stage of the site study.

2. As there is no aerological station at the sites proposed for the (NPP), historical data, related to the (PBL) up to 1000 m have been collected from the Iraqi Meteorological Organization (IMO). These data, which are provided by radiosounds launched at Saddam airport in Baghdad twice a day, include : altitude, atmospheric pressure, relative humidity, mixing ratio, air temperature, wind speed and direction. The data collected from the lower twenty altitudes, calendar years 1985 and 1986 were inputted to the ICL computer in (IMO) to construct a data base. The linear interpolation technique was used to obtain those informations at 20 specific altitudes from 50 m to 1000m.

3. A mathematical model was elaborated to determine the required aerological data which are : surface and upper thermal inversion points, surface and upper isothermal and stagnant layers, vertical wind profile and frequency wind roses at seven altitudes. These parameters are determined for both observations 0.0 and 12hour GMT.

Dust phenomena of different regions in Iraq have been studied. A preliminary survey of data obtained from the Iraqi Meteorological Organization accumulated for the past 47 years indicated that dust storms dominated certain regions of the country but, the frequency of occurrence was highly variable among regions of Iraq. The highest dust storm occurrence was developed over the southwestern parts of the country especially areas such as Nasiriyah, Samawa, Western Basra and, South West Baghdad. Large quantitites of dust generated by wind erosion over land and carried by strong wind from desert areas would dominate the atmosphere as dust storms and reach the climax during the months of April, May, June and July. These facts hold true for all kinds of dust storms such as haze , rising and suspended particles. On the other hand, it was interesting to find that the mean annual number of days with dust storms in Baigi-Sammarra region was averaged 7 days as compared to 27 days in southwestern Nasiriyah area ( 4 folds).

STUDY OF SELECTED ELEMENTS IN WATER, SUSPENDED SOLIDS, SEDIMENTS, FISH AND AQUATIC PLANTS OF RIVER TIGRIS

Eight elements (Cd, Cu, Co, Fe, Zn, Mn, Pb and Ni) were analyzed in filtered water, suspended solids, surficial sediments, fish and aquatic plants of river Tigris and Samarra impoundment during high (April) and low (July) river discharge months. The recorded concentrations in water were either significantly lower or within the Iraqi river water standards and the average clean river water of the world . The observed variation in the concentrations of elements in suspended solids may be due to local differences in current velocity. The concentrations of elements in surficial sediments, except for Co during July, Mn during April and Fe during both months, were lower than that present in the suspended solids. The concentrations of these elements in bones, skin, gills, muscles, liver and kidney in two economically important fish species ( Barbus grypus Heckel and Silurus triostegus Girry) were almost similar. However , variations were argued to be a species specific and indicate their possibilities as a bioaccumulators. Analyses of Typha domingensis Pers., Phargmites australis ( Cav.) Trin. ex stend, Ceratophyllum demersum L. and Potamogeton Lucens L. reflects and polluted nature of some areas within the impoundment and emphasized the importance of emerged and submerged plants as pollution indicators.