Pre-treatment of Organic Liquid Waste Stream at Cernavoda NPP

Abstract

The radioactive waste management system at Cernavoda Nuclear Power Plant (NPP) was designed to maintain acceptable levels of safety for workers and to protect human health and the environment from exposure to unacceptable levels of radiation.

During the ten years operation of the Cernavoda NPP a series of waste streams have been developed for waste management purpose. One of these streams is consist of radioactive organic liquid wastes: spent oils, spent solvents, liquid scintillation cocktails (LSC), flammable solids (solid-organic liquid mixture) and sludge.

Effective treatment of organic liquids waste from the initial to the final stage has been a challenge for NPP Cernavoda. All components of the organic liquid waste stream was stored in liquid form in stainless steel drums in the Solid Radioactive Waste Intermediate Storage Facility (SRWISF). This facility was originally designed for solid wastes only, the regulatory body has asked Cernavoda NPP to remove the flammable liquids from this repository as soon as possible.

As a result, at the end of 2008, Cernavoda NPP initiated the solidification of organic liquid wastes (both historical and "fresh" wastes) together with a separation of solids associated with the organic liquids. In accordance with terminology of the International Atomic Energy Agency (IAEA), this system consists of the "pretreatment" of solid and organic liquid radioactive waste.

In 2008 Mate-Fin sign a contract with Cernavoda NPP in order to treat organic liquid waste and inflamable solid waste. The quantity for the entire 4 years project was about 24 tones of organic liquid waste and inflammable waste and after 2 years Mate-Fin succesfully solidified all historical organic liquid waste.

The proposed solution to this problem is to apply proven, low cost polymers to absorb liquid compositions. The polymers may be combined to create a formula specifically designed to permanently solidify a waste stream in a simple one-step process.

Nochar polymer technology (Nochar Petrobound – N910 and Acidbound – N960) has been successfully deployed in the immobilization of organic liquids waste in Cernavoda NPP. A detailed presentation is given related to the quantities of polymer used to solidify a specific organic liquid waste, possible mixture used for a particular type of liquid, the influence of the liquid properties (ex. impurity content) on the composition (N910 versus N960) of the polymer mixture and quantity.