"Mark I" Reactors

This is an excerpt from an April 24th article appeared on Asahi newspaper. It was written by Toshihiro Yamanaka, chief of the Asahi Newspaper New York bureau.

Fukushima Daiichi reactors No.1 through No. 4 are called Mark I which was made by GE in 60s. Yamanaka captured the news that once there was a furious debate within GE about the safety issues on Mark I. It was in 70s. I will translate and summarize one of two interviews he has reported.



Dale Bridenbau, 79 year old, started to work at GE in 1953. It was the year President Eisenhower pitched the usage of nuclear power for peace at an UN conference. Bridenbau worked as an expert on the safety inspection and travelled to Switzerland, India, Italy, and Japan. In Japan, he made visits to Suruga and Fukushima. He said,




“Of course, the Fukushima accident was caused by the earthquake followed by tsunami. It wasn’t that Mark I self-destroyed itself. But, if I pleaded louder for its improvement at the time, it could have avoided that serious situation. That leaves me regret as an early-stage developer.”



1975 was the year that Mr. Bridenbau and his superior fought on a safety issue. As the result of the Mark III development and tests, he discovered the weakness in the containment vessel of Mark I. If an out-of-ordinary event occurred, and that caused the cooling system to malfunction, then the containment vessel cannot withstand the inner pressure and will be damaged. He suffered with this fact. He told his superior,



“What we need to do right away is to study the threshold of the pressure again and improve on it. For that purpose, we need to stop the operation of all the Mark I reactors.”



The opinion of most GE’s employees differed from his. They said, “If we stop the operation, it will be looked at as a serious problem” and “It would make the surrounding residents uneasy.” At the time, 20 Mark I were already operating worldwide. His plead was rejected. He and two young employees left the company on that day of the argument as the result. It was February 1976.



Then and now, GE has maintained that Mark I has been updated and reinforced, so it has no defect.



In early ‘70s, Japan was behind on nuclear technology. Japanese engineers put all their effort in learning by imitating the U.S. technology. Nobody dared to ask hard questions and investigate themselves, I guess. Right now, 32 Mark I exist in the world. We need to confirm if all the Mark I reactors have been followed up with all the appropriate updates and reinforcement GE claims they have. No time to wait.



I read that, so far, the total number of nuclear reactor accidents is 12. The U.S. had 4, France, 2, Germany, Scotland, and Russia, 1, and Japan, 3. We must stop the accident from Japan. Japanese cannot afford to sit and being agreeable anymore.



No matter how bad the situation is, we need to know. How people would react to the news is each person’s responsibility. We still need to know.



Today’s Asahi, I found the following sentence under the article “Question into Japan’s Global Accountability.” “The U.S. Nuclear Regulatory Commission (NRC) has cancelled the partnership with Toshiba to further set up nuclear reactor plants.”

Calculating Risk

An Old and Prized Cherry Tree Behind Gumyoji Kannon

Below is an excerpt from May issue of Bungeishinju magazine. The title of this interview-styled article is “The Truth Is It Takes A Year,” and the subtitle is “Erroneous Reports on Radiation.”



Interviewer: Koichi Okamoto, specialized in Crisis Psychology, Professor at Toyo-Eiwa Women College, a specialist member of Nuclear Energy Safety Committee and Nuclear Energy Committee

Interviewee: Masayori Ishikawa, Professor of the Graduate School of Hokkaido University
Studied and worked at Kyoto University Nuclear Reactors Research Center, Tokyo University Nuclear Power Research General Center, Hokkaido Hospital,

The Petals of the Cherry Blossoms 

On page 209, this is what the interviewee said.




“To evaluate the amount of radiation, we have to add how much exposure we collected throughout our lifetime, not just in days.”


A friend of mine has recently told me that after the Hiroshima bomb, the radiation fall out onto the Kanto region--Tokyo and Yokohama included, was 10,000 times more than the previous norm. I didn’t know that. My parent died without knowing it.


“This is based on the current statistics. If our accumulated amount passed 100 mili sieverts, and if we added more, per 1000 mili sievert (1 siervert), the cancer rate would possibly go up 5 %. Therefore, if a person were exposed to 100 mili sieverts so far in her or his life, and also the probability of that person to afflict with a cancer were 50 %, then the rate becomes 50.5 %.

Today, one person out of two gets cancer, and one out of three dies by cancer. Being aware of these facts and the accumulated amount of our own radiation exposure and risks, we can choose the way we live.”


So far, I know the Japanese average is 1.45 mili sierverts a year. The Hiroshima and Nagasaki bombs happened before I was born. My mother and aunt must have exposed to the 10,000-times-over-the-norm radiation, and the descendants like us are I’m sure affected. I moved to the U.S. in 1970. So, I want to know the U.S. average by state, city, and town. My mother died of liver cancer at age 76, but my aunt moved to the U.S. around 1955, and she is 87 and has dementia, but as far as I know, she doesn’t have cancer.

I hope this helps.