The decision to start up the reactor was made despite widespread protests and the fact that approximately 70% of Japanese want the government to prohibit the use of nuclear power indefinitely.
According to NHK some 7,000 protesters marched through Tokyo in opposition to the planned restart and to nuclear power, calling for a ban on nuclear power production.
The Ohi nuclear power plant uses pressurized water reactors (PWR) unlike those that melted down at Fukushima, which were boiling water reactors (BWR). They are both classified as light water nuclear reactors. The main difference between a BWR and PWR is that in a BWR, the reactor core heats water, which turns to steam and then drives a steam turbine.
In a PWR, the reactor core heats pressurized water which does not boil but does reach the boiling point. This hot water then exchanges heat with a lower pressure water system, which does in fact boil and turns to steam to drive the turbine.
The BWR was developed in the U.S. by the Idaho National Laboratory and General Electric in the mid-1950s.
The particular model used at Fukushima had inherent design flaws in the containment structure from the outset and engineers predicted the exact scenario that happened at Fukushima.
The General Electric Corporation began constructing the Mark-1 BWR reactors in the 1960s, claiming that they were cheaper and easier to build in part because they used a smaller and less expensive containment structure, and this is where the main problems lie.
A fact sheet published from the anti-nuclear advocacy group Nuclear Information and Resource Service, which is available on the internet, details problems with the design and states that in 1972 an Atomic Energy Commission member, Dr. Stephen Hanuaer, recommended that this type of system be discontinued.
More questions arose about the design in the mid-1980s, after Nuclear Regulatory Commission official Harold Denton stated that the Mark-1 reactors had; “…a 90 percent probability of bursting should the fuel rods overheat and melt in an accident.”
Thirty-five years ago, while reviewing the design for the Mark-1, Nuclear Engineers Dale G. Bridenbaugh and two of his colleagues at General Electric were pressured into okaying the designs for the Mark-1 and were forced to resign after becoming convinced that the Mark 1 was so flawed it could lead to a catastrophe.
The key issue in this piece is, and there is very little detailed information out there on the subject, how many of Japan’s nuclear power plants run the G-E BRW Mark-1 reactors. All of the Fukushima reactors used the Mark 1 containment system while the sixth had the upgraded to Mark 2 system.
Below is a list of all Japanese ВRW reactors.
Reactor Location Type Containment Rating Status Operator
Fukushima I-1 Futaba, Fukushima BWR 439 Meltdown/exploded March 2011 TEPCO
Fukushima I-2 BWR Mark I 760 Meltdown March 2011 TEPCO
Fukushima I-3 BWR Mark I 760 Meltdown/exploded March 2011 TEPCO
Fukushima I-4 BWR Mark I 760 Meltdown/exploded March 2011 TEPCO
Fukushima I-5 BWR Mark I 760 Operational April 18, 1978 TEPCO
Fukushima I-6 BWR Mark II 1067 Operational October 1979 TEPCO
Fukushima II-1 BWR Mark II 1067 Operational April 1982 TEPCO
Fukushima II-2 BWR Mark II A 1067 Operational February 1984 TEPCO
Fukushima II-3 BWR Mark II A 1067 Operational June 1985 TEPCO
Fukushima II-4 BWR Mark II A 1067 Operational August 1987 TEPCO
Genkai-1 PWR 529 Operational October 1975 Kyūshū Electric
Hamaoka-1 BWR 515 Operational March 1976 Chūbu Electric
Hamaoka-2 BWR 806 Operational November 1978 Chūbu Electric
Hamaoka-3 BWR-5 1056 Operational August 1987 Chūbu Electric
Hamaoka-4 BWR-5 1092 Operational September 1993 Chūbu Electric
Higashidōri-1 BWR 1067 Operational December 2005 Tōhoku Electric
Kashiwazaki-Kariwa-1 BWR 1067 Operational September 1985 TEPCO
Kashiwazaki-Kariwa-2 BWR 1067 Operational September 1990 TEPCO
Kashiwazaki-Kariwa-3 BWR 1067 Operational August 1993 TEPCO
Kashiwazaki-Kariwa-4 BWR 1067 Operational August 1994 TEPCO
Kashiwazaki-Kariwa-5 BWR 1067 Operational April 1990 TEPCO
0Onagawa-1 BWR 498 Operational June 1984 Tōhoku Electric
Onagawa-2 BWR 796 Operational July 1995 Tōhoku Electric
Onagawa-3 BWR 798 Operational January 2002 Tōhoku Electric
Shika-1 BWR 505 Operational July 1993 RIKUDEN
Tōkai-2 BWR 1056 Operational November 1978 JAPC
Tsuruga-1 BWR 341 Operational March 1970 JAPC
JPDR-II BWR 13 1963–1982
Maybe it is time that all of these reactors were upgraded or shut down. Most have been on-line since the 1970s, and it is doubtful they become safer with time.
The opinions and views expressed here are the writer’s own.