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Large number of accidents that have occurred in three major practices, namely: industrial radiography, gamma irradiators, and radiotherapy. A radiological accident involves a sealed or unsealed radiation source leads to an uncontrolled release of ionizing radiation or radioactive materials into the environment, which may result in significant human exposure and/or material damage. A major accident occurred in greater Cairo Area during 2000 due to bad practice and human error. A radiological source (Ir-192 capsule with activity 31.5 Ci) was lost at the examination site near the pipe. Members of the public were plucked up. At least seven persons have exposed to overdoses, two of them died due to overexposure dose. In this study, the absorbed radiation doses and the associated hazards due to uncontrolled radioactive sources Ir-192 and Cs-137 are calculating using RESRAD-Building computer code. An overview of the consequences and the obtained results are registered in lessons learned study would clarify the necessary that the regulatory authority to introduce measures capable to avoid the recurrence of similar accidents.

As a result of a fire or explosion in nuclear fuel fabrication facilities two risks to health and safety. Mitigation of fire hazards and radioactive release necessitates the use of fire-resistant and appropriate shielding materials, specifically plastic tubes used in chemical reactions during the conversion process. This paper aims to study the thermal stability, flammability, and shielding properties of polyvinylidene fluoride (PVDF) tubes used in the aqueous solutions sector of the Egypt Fuel Manufacturing Pilot Plant (FMPP), to can replacement the consumed one by another from the local market with the same property. For this purpose, PVDF samples were tested by Energy Dispersive X-ray spectroscopy (EDX) and X-ray direction (XRD). Thermal analysis tests as thermogravimetric analysis (TGA) as well as the derivative of thermogravimetric analysis (DTGA). The ignition test was applied using a limiting oxygen index (LOI), flame chamber (UL/94). 137Cs radioactive source of 5mCi activity was used for gamma shielding properties measurement. Shielding parameters of fast neutrons like removal cross-section and mean free path was calculated. Results of (TGA), showed that PVDF has good thermal stability, where weight loss (about1%) is observed at a temperature above 422ºC. PVDF sample successfully passed the UL-94 H-0 rating with a Limiting Oxygen Index (LOI) of about % 44.8. Also, it has appropriate shielding properties due to the high content of fluorine atoms. PVDF containing Al metal in their composition is more effective for the attenuation of fast neutrons.

Abstract. The transition from emergency to existing exposure situation is an important stage in the nuclear or radiological emergency plan. It requires arrangements to be put in place and to be implemented so as to ensure that the transition is made in a coordinated and orderly manner of guidelines for adjusting the undertaken protective actions and other response actions. The delivering radiation doses to public and environmental pollution are monitoring that measurements should be implemented according to certain plan of intervention and protective actions in the different stages of the N/R accident. In this study, a computer model (RASCAL) is used to calculate the effect of severe accident could have detected on an operating nuclear power reactor PWR and the possible impact on the public. Features for the decision to implement the transition from emergency to existing exposure situation are proposed depending on the estimation of the collection of deliver exposure doses to the public and environment due to monitoring the different radiation sources resulting from the N/R accident.