Natural Cooling System Design and Forced Draft Test for Highly Radioactive Vitrified Waste Packages Storage Pits

Vitrified Waste Storage Facilities, which store high-level radioactive vitrified waste packages with natural air-cooling system, have been constructed at JNFL’s Rokkasho Reprocessing Site. [1] Construction work for the first vitrified waste storage facility which stores the waste packages vitrified in Rokkasho site was completed in December in 2005. After the final inspection, a forced draft test was conducted to verify actual fluid resistance throughout the flow passage. The test results show that the measured pressure loss is less than 70Pa at design flow rate and that it has approximately 10% margin to the design value. This confirms that the facility has the adequate cooling performance.