The facility at Bataapati is one of the first (LILW) radioactive waste repositories in the world. The disposal chambers are located in pairs contained in 3 underground caverns excavated 200 – 250 m deep within the granite bedrock and these are each 90 – 110 m in diameter. The first disposal chamber is designed to take about 40,000 m³ of radioactive waste that is crushed and compressed into 4600 steel drums, which are to be contained in 510 reinforced concrete containers before placing these into the chamber. The chambers will then be sealed and backfilled with a mixture of clay and concrete with 50 – 60% crushed granite.
The disposal chambers were required to be lined with a high quality sprayed concrete inner shell, several centimetres thick. The sprayed concrete design was specified by the responsible engineers as follows:
- Concrete: C30/37 – XV2(H) – 8 – F5
- w/c ratio: ≤ 0.55
- Flow table spread: 560 – 620 mm
- Early strength development: J2
From past experience Sika was selected to provide the necessarily comprehensive support and sprayed concrete solutions for this project, including full compliance with the latest EFNARC standards and regulations. This required detailed site inspection services and the fresh concrete checks and monitoring, together with full site support for the sprayed concrete machinery and equipment, plus all of the necessary training of the nozzlemen and other key operators throughout the works.