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Abstracto

Risk assessment for retrieving legacy radioactive waste in Al-Tuwaitha site

Emad S. Shamsaldin, Asia H. Al-Mashhadani and Saad M. Abd

The large quantities of radioactive waste (RW) in Iraq are of different origins. Some of the waste was produced in the former Iraqi Atomic Energy Commission IAEC –Nuclear Research Centre (NRC) activities in the fields of (physics, chemistry, medicine, agricultural and other nuclear activities) which certainly produce radioactive waste. The waste were properly collected, packed and disposed in a special concrete facility so called the Russian Silo, which was built in the early sixties of the last century. This facility is still intact and contains radioactive waste of the sixties, seventies and eighties. The log book and all documents of the radioactive waste were lost in the successive wars and looting in the 2003 events. The management of the radioactive waste is basically depends upon the inventory of the RW which in turns depends upon the proper classification of the RW, and accordingly the type of treatment and the end point of the RW (i.e. the type of disposal facility)will be decided. RW in the Russian silo were covered and it is very difficult to quantify or qualify by external measurements because of the heavy concrete shielding of the facility. The Russian Silo was re-equipped with 5 ton bridge crane to enable the removal of the concert plugs (covers)of the wells. For radiation protection purposes the wells were numbered and a dose map at the top and the sides of the facility were drawn. The radiation dose rate for each well were measured before and after the removal of the concrete plugs, each well were identified for the radionuclide that is contaminating the waste, it has been used a very sophisticated, well advanced hand held HPGe detector with an efficiency 42% produced by ORTEC to obtain more reliable and accurate results for the risk assessment calculations. More than 95% of the concrete wells were an uncovered. It was noted the following:- 1-Most of RW are either combustible or compressible. 2-The most predominant contaminant is Cs-137, Co-60 and Pa-234. 3-Some of the well constituent were measured and identified and the concentration levels were around 5.04×104Bg /kg. 4-The end point of the RW were identified as near surface disposal facility