Tepco completes unit 4 fuel removal
22 December 2014
Tepco has completed a major program of clean-up at Fukushima Daiichi - the removal of all nuclear fuel from unit 4. President and CEO of the company Naomi Hirose paid respect to the "skill and commitment of Tepco engineers and workers at every level".
Some 1331 used fuel assemblies and 202 unused ones have now been transferred from the pool at the top of Fukushima Daiichi 4's heavily damaged building. The heat-producing used assemblies are in a common pool for longer-term storage, while the fresh assemblies that produce no decay heat are kept in the storage pool of undamaged unit 6.
The end of the year-long removal procedure is a huge achievement for Tepco because it brings about the incident-free completion of a major engineering challenge. After clearing tonnes of radioactive debris from the top of the unit 4's building Tepco constructed a cantilevered structure and airtight cover. This contained all the equipment used at a normal nuclear power plant to take fuel from the storage pool and place it in transport canisters and place these on specialised trucks for transport across the site.
Removal of the used fuel from the damaged building eliminated the largest radiological hazard at the site, and now removal of the fresh fuel means the entire operation is over.
President and CEO of Tepco Naomi Hirose said, "That this was done safely and without incident is a testimony to the skill and commitment of our engineers and workers at every level, and to the many other organizations, in Japan and from around the world, that contributed their knowledge and resources. I wish to express my personal gratitude, and that of our company, to all of them."
Hirose said: "Most importantly, it makes unit 4 a safer place to work, and it adds to the safety of the communities near the facility." He added that it "allows Tepco to turn its attention to its next tasks with the benefit of experience, enabling it to work even more safely and more efficiently."
Hirose said: The damaged building of unit 4 still requires very careful dismantling, made more complex by contamination throughout the building. However, the removal of nuclear fuel from any nuclear facility is a step that marks the official start of the decommissioning process.
Tepco continues to investigate conditions inside the other damaged reactors - units 1, 2 and 3. These suffered core melt accidents after the tsunami of 11 March 2011 and it will take substantially longer to remove this highly radioactive material.
Researched and written
by World Nuclear News