RADIOLOGICAL IMPACT OF USING DECORATIVE GRANITE AS AN ATTENUATOR OF IONIZING RADIATION.

Granite is a widely available rock, which can be used as a shielding material, for bulk in the form of the aggregate in concrete. It has the weakness that it is more radioactive than many other rocks, which can be used in concrete. This paper looks at its properties as a shielding material and the activity level. Thus, the concentrations of 226Ra, 232Th and 40K, in granite were measured using a high pure germanium detector (HPGe). They were ranged from (15 ± 4 to 49 ± 5) Bq kg-1 for 226Ra, (22 ± 4 to 78 ± 4 Bq kg-1) for 232Th and (791 ± 13 to 1231 ± 15 Bq kg-1) for 40K. Radiological indices of radium equivalent concentration (Raeq), external (Hex), internal (Hin) and annual effective dose were less than worldwide recommended limits. The results emphasized, the granite samples had no radiation hazard. Nevertheless, the mass attenuation coefficients of granite samples were measured for the gamma rays of energy range 122-1408 keV. The mass attenuation coefficients of the studied granite samples were ranged from 0.05 to 0.15 cm2 g-1. In addition, the average the half-value layer of granite was varied from 1.8 cm for 122 keV to 5.2 cm for 1408 keV. The results are that the attenuation characteristics are typical and match the values given by NIST for 'concrete' and that the activity levels of the samples examined are acceptable. Thus the granite may be used as an attenuator for ionizing radiation.

ASSESSMENT OF RADIOLOGICAL HAZARDS OF USING PETROLEUM RAW MATERIALS AND THEIR WASTE.

Activity concentrations of 238U, 232Th and 40K in raw and waste petroleum materials (Egypt and Kuwait) were measured using gamma ray spectrometer. The average values of 226Ra, 232Th and 40K were 21.1 ± 3.2, 7.6 ± 1.3 and 88.4 ± 8.2 Bq kg-1 for Egyptian samples while for Kuwaiti samples, they were 25.2 ± 3.4, 6.1 ± 2.2 and 67.8 ± 6.4 Bq kg-1, respectively. All samples had activity less than the exemption level recommended by the International Atomic Energy Agency. Moreover, radiological indices of radium equivalent, external, internal, alpha and gamma indices and radiation dose as well were calculated and their values were lower than the recommended regulatory limits. Thus, radiation exposure to petroleum materials did not present a significant radiological hazard.

Full core analysis of IRIS reactor by using MCNPX.

This paper describes neutronic analysis for fresh fuelled IRIS (International Reactor Innovative and Secure) reactor by MCNPX code. The analysis included criticality calculations, radial power and axial power distribution, nuclear peaking factor and axial offset percent at the beginning of fuel cycle. The effective multiplication factor obtained by MCNPX code is compared with previous calculations by HELIOS/NESTLE, CASMO/SIMULATE, modified CORD-2 nodal calculations and SAS2H/KENO-V code systems. It is found that k-eff value obtained by MCNPX is closer to CORD-2 value. The radial and axial powers are compared with other published results carried out using SAS2H/KENO-V code. Moreover, the WIMS-D5 code is used for studying the effect of enriched boron in form of ZrB2 on the effective multiplication factor (K-eff) of the fuel pin. In this part of calculation, K-eff is calculated at different concentrations of Boron-10 in mg/cm at different stages of burnup of unit cell. The results of this part are compared with published results performed by HELIOS code.

Effect of pretransplant hepatitis C virus on the development of new-onset diabetes mellitus after transplant in Egyptian living-donor renal allotransplant recipients at Mansoura Urology and Nephrology Center.

OBJECTIVES: New-onset diabetes mellitus after transplant is a common complication in renal allograft recipients. Recently, a high prevalence of diabetes mellitus has been reported in patients with chronic hepatitis C virus. The association between hepatitis C and diabetes mellitus is well demonstrated in the general population, but some controversy still exists. This work aimed to study the effect of pretransplant hepatitis C virus on the development of new-onset diabetes mellitus after transplant in Egyptian living-donor renal allotransplant recipients. MATERIALS AND METHODS: This retrospective single center study included 913 kidney transplant recipients who were transplanted at Mansoura Urology and Nephrology Center between 2000 and 2010. The patients were divided into 4 groups according to their hepatitis C virus serology and diabetic status. RESULTS: Pretransplant dialysis duration and number of blood transfusion units were statistically significant among both viremic and nonviremic groups. With respect to induction therapy, a highly statistical significance was observed between the 4 groups regarding presence and type of adjuvant therapy (P < .001). With respect to maintenance immunosuppression, high statistically significant results were observed regarding steroid and rapamycin between the 4 groups (P < .001) with lower significance regarding mycophenolate mofetil (P = .04) but no significance regarding azathioprine, cyclosporine, or tacrolimus therapy. Incidence of new-onset diabetes mellitus after transplant was statistically higher in the viremic than nonviremic group (P < .001). CONCLUSIONS: There was a positive correlation between incidence of new-onset diabetes mellitus after transplant and positive pretransplant hepatitis C virus status.

Evaluation of radionuclide concentrations and associated radiological hazard indexes in building materials used in Egypt.

Radionuclide concentrations of ²²6Ra, ²³²Th and 4°K in different types of building materials used in Egypt were measured using gamma-ray spectroscopy. The results showed relatively moderate radionuclide concentrations for all samples except granite, which showed extremely high concentrations of 78.75 ± 2.36, 2.82 ± 0.11 and 2.37 ± 0.07 kBq kg⁻¹ for ²²6Ra, ²³²Th and 4°K, respectively. The radiological hazard indexes of radium equivalent activity (Raeq), external hazard index (Hex) and internal hazard index (Hin), due to the presence of those radionuclides in the investigated building materials, were calculated. The released radon from the selected samples was measured using the AlphaGUARD radon monitor in order to use its value to calculate the radon emanation coefficient and the radon exhalation rate. The alpha equivalent dose (dose from indoor radon generated from building materials) was calculated using the measured values of the radium concentration and the radon emanation coefficient.