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About Street roots. (Portland, OR) 1998-current | View Entire Issue (Aug. 28, 2015)
Street Roots • Aug. 28-Sept. 3, 2015 Allowing plants to restart would ignore lessons learned from Fukushima, expert says B Y RIE M A TS U O K A made the external power more earthquake resistant, but for them our idea looks senseless.” ore than four years after the Ino points out that cost is also a big factor Fukushima disaster, no nuclear playing out behind the scenes: “In order to power plants have operated in enhance the entire plant’s level of Japan. At least that was the case until earthquake resistance, you must make the August 2015, when the Sendai nuclear plant whole system within and around the in southern Japan became the first to begin premises earthquake resistant, including operation since the 2011 Fukushima pylons, wiring and the thermal power plant meltdowns, despite anti-nuclear protests. itself, which would cost a huge amount of An additional 23 units in 14 nuclear power plants are applying for the green light money. That is why power companies are not willing to do it.” to resume operations. To do this, tiiey must Nuclear power plants are built taking into pass a safety review conducted by Japan’s consideration not only safety but al^o the Nuclear Regulation Authority. balance of safety, costs (economic < But the plan to resume nuclear | . efficiency), performance and environmental operations fails to reflect on the lessons we burden, among other factors. “This sense of have learned from Fukushima, warns balance applies not only to a nuclear power Hiromitsu Ino, a former Tokyo University plant, but also to many other things,” says professor and specialist in metallic material engineering. Ino. “However, if and when a nuclear power “At the moment, the Abe government is plant has an accident, the damage is attempting to revive nuclear power stations enormous. We need to emphasize safety by arid trying to return the evacuated all means. But they evaluate the balance at inhabitants to their home. However, we do the same level as in any other technology. It hot have any clear plan to restore the is both ridiculous and dangerous to resume damaged area yet. We must use our a nuclear power plant in this situation.” Commenting on the nuclear power plants experience of the Fukushima accident as the base when we consider the future,” says built in the 1970s, Ino says, “The design Ino, who has already raised major concerns concept is bad and the materials are also over the risks involved in resuming nuclear bad. They are built based on the assuinption operations across the country. of an operating life of 30 to 40 years. Such “First.of all, I want to emphasize that the common material as stainless steel were common sense of the nuclear power used. The material of pressure containers community is senseless for citizens, and the contains copper impurities. When neutrons common sense of citizens is senseless for hit the containers, copper fuses together the nuclear power community,” says Ino. and forms clusters, making that part stiff, “During the Fukushima accident, all the brittle and therefore easier to break.” external power was cut down and the The boundary temperature before a internal emergency diesel generators were material breaks is called “brittle transition also damaged. We wonder why they had not temperature.” For example, copper’s brittle C O N T R IB U T I N G W R IT E R M transition temperature is usually about minus 20 degrees centigrade, but as the material gets older the brittle transition temperature rises. The worst is 99 degrees in Unit 1 of Takahama Nuclear Power Plant, followed by 98 degrees in Unit 1 of Genkai Nuclear Power Plant. The higher the brittle transition temperature; the higher the risk of the container breaking. Additionally, when the core cooling system functions as an emergency measure and cold water flows into the container, only the inside " li t e common sense of part of the container is the xstxclear power com* rapidly Cooled down. The oioaity Is senseless for temperature difference citizens, and the com* between inside and outside moa sense of citizens Is could generate some force senseless fo r the nuclear and break the container from inside. power com m unity." “If the pressure container H ie o M iT s w im o , EXPERT IN METALLIC: M A T E R IA L is broken, we can no longer ENGINEERING cool it down with water,” explains Ino. “The meltdown will surely start. If there ir hydrogen around, there is a risk of explosion as well. When the containment vessel is blown away, the radioactive substances will disperse in the area of 250 kilometers in radius, causing damage much more serious than the Fukushima Daiichi accident.” Unit 1 of Genkai Nuclear Power Plant has been officially decommissioned, but there are still hopes that Unit 1 of Takahama Nuclear Power Plant could once again become active. “The reason is that while the output power of Genkai is relatively small, 50 kW, that of Takahama is nearly See NUCLEAR, page 7
