Hiroshima : 70 Years After the A-bombing

Hiroshima Asks: Toward the 70th Anniversary of the Atomic Bombing: Why can’t nuclear weapons be abolished?

by Yumi Kanazaki, Kohei Okata, and Keiichiro Yamamoto, Staff Writers

The year 2015 marks the 70th anniversary of the atomic bombings of Hiroshima and Nagasaki. The people of these two cities have long advocated that the abolition of nuclear weapons is the only way to prevent another inhumane catastrophe from occurring. Ignoring the appeals of the A-bombed cities of Hiroshima and Nagasaki, more than 2,050 nuclear tests have been carried out since World War II, creating new radiation victims near the test sites and causing environmental destruction around the globe.

During the past decade, North Korea has pursued a series of underground nuclear tests. Meanwhile, other nuclear powers seem to be developing smaller and more advanced nuclear weapons. Tests that produce a nuclear explosion are now outdated.

Today’s nuclear tests may no longer create a huge mushroom cloud, but the nuclear arms race is not over. The nuclear armed states are spending huge sums of money to “modernize” their nuclear warheads and delivery vehicles. The obligations to seek nuclear disarmament, as stipulated in the Nuclear Non-Proliferation Treaty (NPT), are being undermined.

The United States armed its nation with a score of nuclear weapons during the Cold War era, then reduced this arsenal by over half. Yet at the same time, it is pursuing all possible measures to ensure that the performance of its remaining weapons is maintained. The so-called “Z machine” at the Sandia National Laboratories in New Mexico is a state-of-the-art facility for conducting experiments on the performance of these weapons.

As long as nuclear arms exist in the world, there is always a chance that they could be used. Hiroshima asks policy makers of the world and the government of Japan: Why not embark on a path which leads to eliminating nuclear weapons? Now that these weapons are evolving and their quality is growing more important than their quantity, now is the time to take steps forward.


Visit to the Z machine facility in the United States

It is said that the building quakes when a test is conducted at the Z Pulsed Power Facility at the Sandia National Laboratories. With the use of the Z machine, the world’s most advanced equipment for testing the “safety and security” of the nuclear stockpile, their performance can be examined without a detonation. The Chugoku Shimbun visited this facility in early December to learn how nuclear tests are evolving.

The feel of a factory tour

Inside the building is a huge cylindrical tank-like installation with a diameter of 33 meters. This is the Z machine. To the stench of oil and the scream of a siren, a large part of the machine was lifted with a crane. The noise produced was deafening, like that of an electric generator. It had the feel of a factory tour.

Joel Lash, 45, the senior manager of the facility, explained that the smell came from the large amount of transformer oil which filled the tank and acted as an insulator. In another part of the facility, where ultrapure water was the insulator, a diver was checking the equipment in the water.

By generating powerful X-rays at its center, the machine can recreate conditions of extreme temperature and pressure similar to those produced by a nuclear detonation. It can be used to confirm whether aging plutonium is maintaining its expected quality, or to obtain data regarding how it reacts under extreme conditions. The “Z” of the Z Pulsed Power Facility is derived from a phenomenon in which plasma particles generated in the center of the machine pile up in the z-axis, which represents depth.

Between 150 and 200 experiments are conducted annually. Various materials used for nuclear warheads, including iron, are tested. Several tests that use plutonium are carried out each year to check how the materials might respond under extreme circumstances and to collect needed data for computer simulations.

Gap in perception

Mr. Lash takes pride in this facility, saying that it contributes to the progress of science and technology in many ways. There is a continuous stream of visitors from home and abroad, he said, including researchers and government officials. As the equipment can create conditions similar to the interior of stars, the facility can provide useful information for the study of the core of the sun and the earth and white dwarf stars, which are smaller stars approaching the end of their lives. Very basic research into nuclear fusion energy also benefits from the facility’s work, Mr. Lash said.

But the construction of the Z Pulsed Power Facility, and the costs associated with its experiments, are part of the budget for the nation’s nuclear arms and come from the National Nuclear Security Administration (NNSA), an autonomous agency under the U.S. Department of Energy. In reality, most of the experiments conducted there involve maintaining the performance of the nuclear arsenal.

In the United States, the military and science are closely linked, and research on state-of-the-art nuclear weapons is underway. The cities that suffered the atomic bombings are firmly opposed to any nuclear tests, regardless of their scale or form, which are designed to maintain nuclear weapons. This tour of the Z Pulsed Power Facility brought home the wide gap in perception between the two sides.


Senior researchers: Need to ensure nuclear deterrence for Japan’s security

The Chugoku Shimbun interviewed Keith Matzen, 67, director of the office of nuclear weapons science and technology at the Sandia National Laboratories, and Duane Dimos, 56, director of the Sandia Pulsed Power Sciences Center. These laboratories are in charge of testing the performance of the materials used in the U.S. nuclear stockpile with the use of the Z machine.

What is the purpose of these experiments?
We want to examine how the quality of the plutonium and other materials evolves since the time the warheads were produced. We sample different kinds of warheads produced in different years, and test whether the materials react as expected in an extreme environment with powerful X-rays. The plutonium we use is brought from the plutonium facility called “TA-55” located in the Los Alamos National Laboratory [about 160 kilometers to the north of the laboratories]. Our experiments are carried out in line with the “Stockpile Stewardship Program” (SSP) conducted by the National Nuclear Security Administration.

Are you aware that people in Hiroshima and Nagasaki raise their voices in protest each time a test is conducted using the Z machine?
We don’t know all the details on every occasion, but we certainly understand that concerns have been expressed about these experiments. We hope, though, that the people of Hiroshima and Nagasaki will gain a better understanding of the work that we do here.

Plutonium samples are like a thin dime [about 1.8 centimeters in diameter], and their maximum weight is 8.4 grams. Tests are conducted with the utmost care, and there has not been a single leakage. The word “nuclear tests” might be associated with massive nuclear explosions, but these experiments are completely different.

You stress that the machine contributes to maintaining the reliability of the nuclear arsenal without producing an explosion. Nuclear deterrence must be assured into the future without explosive testing. This facility is one of those working for that purpose. Data collected here is used for validating physics models in supercomputer simulations.

If enough test data is obtained using the Z machine, will there be no need for subcritical nuclear tests?
While subcritical tests are more integrated experiments regarding the reliability of nuclear weapons, the experiments at Z machine focus on particular physical data. The reliability of the nuclear arsenal will be strengthened when both types of experiments are performed.

The United States regards the Life Extension Program (LEP), which seeks to extend the useful lives of nuclear warheads, as part of the Stockpile Stewardship Program. But this is criticized as an intention to increase the capability of the arsenal, not as a method of maintenance. Doesn’t the Z machine contribute to the modernization of nuclear weapons?
We would say that this is refurbishing, not modernization. For example, 50 years have passed since the B61 nuclear bombs were produced. In order to maintain their reliability for the next 50 years, it’s necessary to make reasonable efforts to achieve this end. This is different from upgrading nuclear weapons.

The people of Hiroshima and Nagasaki, who have been calling for the abolition of nuclear weapons, are, above all, opposed to any measures which will enable nuclear arsenals to be maintained. In his Prague address, President Barack Obama stated that the United States will maintain the reliability of the nation’s nuclear deterrence to defend our allies until a “world without nuclear weapons” is realized. Until the number of nuclear weapons is reduced to zero, the United States is responsible for guaranteeing reliable nuclear deterrence for our allies, including Japan and member nations of the North Atlantic Treaty Organization.


Interview with Kazumi Mizumoto, vice president of the Hiroshima Peace Institute at Hiroshima City University

Working together with victims of radiation damage and continue saying “No”

The Chugoku Shimbun interviewed Kazumi Mizumoto, the vice president of the Hiroshima Peace Institute at Hiroshima City University, on U.S. intentions in conducting nuclear tests with the Z machine and on the meaning of continuing protests from Hiroshima.

Why do you think the United States continues to carry out these nuclear tests?
The United States says that its nuclear tests are intended to maintain the performance of its nuclear arsenal, but it pursues many other kinds of tests beyond those which use the Z machine. Some tests are carried out not only for the civil use of the technology, but for military purposes, too. So the United States maintains these research facilities, researchers, and budgets in order to maintain the technology for weapons, should this become necessary.

In 2012, the United States made public a video of a subcritical nuclear test on the Internet. The website of the Department of Energy proudly states that their technology was given an award by a science and technology journal. I don’t think the researchers feel guilt over their work in maintaining the U.S. nuclear arsenal.

What problems does nuclear testing pose, starting with the beginning of the development of atomic bombs, continuing through the Cold War, and leading to the present?
The moratorium on atmospheric and underwater nuclear explosions has been observed, since these could seriously harm the environment. But an explosion is only the last phase of a nuclear test, and the nuclear weapon states have continued to develop and maintain the technology necessary to produce detonations even though they no longer pursue tests that result in explosions. The United States has revealed the level of technology it possesses, to some extent, but we have no idea about the level of nuclear capability held by the other nuclear powers, though we are aware of the numbers of nuclear warheads in their arsenals.

The United States has always claimed that its tests to measure performance are not counter to the Comprehensive Test Ban Treaty (CTBT). The CTBT bans nuclear explosions, so in theory, they are correct. But the purpose of the CTBT is to stop the development of nuclear weapons. The United States is seeking to maintain its nuclear arsenal, so this is clearly counter to the spirit of the treaty. Even if the CTBT comes into force, there will be no stopping subcritical nuclear tests or the use of the Z machine, if things don’t change. The only way to comprehensively prohibit nuclear tests would be to outlaw nuclear weapons under a new multilateral treaty.

Why doesn’t the Japanese government make any objection to U.S. nuclear tests?
I believe they think that, as long as Japan is under the U.S. nuclear umbrella, the performance of these weapons should be maintained to a certain level in order to ensure that the umbrella remains effective.

What meaning is there, in your view, for the people of Hiroshima to continue protesting U.S. nuclear testing?
President Barack Obama has said that the United States will never relinquish its nuclear arsenal as long as there is another nuclear power in the world. This means that the United States will be the last country to end its dependence on nuclear weapons for its security. If the United States is serious about realizing a world without nuclear arms, it should take the initiative in searching for ways to create security without relying on such weapons. Hiroshima, arm in arm with victims of radiation damage produced by nuclear tests, nuclear power plant accidents, and in other ways, should keep saying “No” to the existence of nuclear weapons.


Kazumi Mizumoto
Kazumi Mizumoto was born in Hiroshima in 1957. After graduating from the Faculty of Law at the University of Tokyo, he earned a master’s degree from the Fletcher School of Law and Diplomacy at Tufts University in the United States. He became an associate professor at the Hiroshima Peace Institute at Hiroshima City University in April 1998 after serving as chief of the Los Angeles bureau of the Asahi Shimbun. Mr. Mizumoto was promoted to professor in April 2010. He assumed his current post in October of the same year.


Sit-ins staged in anger in front of Cenotaph for A-bomb Victims after each nuclear test

Opposition to nuclear tests gained steam in Japan after the U.S. hydrogen bomb test at Bikini Atoll in the Marshall Islands on March 1, 1954.

The test contaminated the tuna fishing boat Daigo Fukuryu Maru (Lucky Dragon No. 5) from Shizuoka Prefecture, and its 23 crew members were exposed to a large amount of radioactive fallout. Tuna caught by other boats were also contaminated with radiation. “Radioactive rain” created by nuclear tests performed by the United States and the former Soviet Union also added to people’s fears. Signature drives to ban atomic and hydrogen bombs were born in Suginami Ward, Tokyo, and Hiroshima, among other places, and spread across the nation. This movement led to the first World Conference Against Atomic and Hydrogen Bombs held the following year, in 1955.

Nuclear arms race intensifies

But the nuclear arms race steadily intensified. In March 1957, frustrated with continued nuclear testing, the late Kiyoshi Kikkawa, “Atomic bomb victim No. 1,” and other A-bomb survivors held a sit-in protest in front of the Cenotaph for the A-bomb Victims for about a month.

Organized sit-ins have been held after each nuclear test since July 1973, when France conducted a nuclear test. Along with other groups, the two factions of the Hiroshima Prefectural Confederation of A-bomb Sufferers Organizations, which had split over a conflict within their ranks, came together to launch an association which eventually became the Hiroshima Alliance of A-bomb Survivor Organizations (Hidanren).

The icon of the sit-in protest was Ichiro Moritaki, a philosopher and professor emeritus at Hiroshima University. He staged 475 sit-ins in front of the cenotaph, rain or shine, between April 1962 and his death in January 1994.

“We asked ourselves whether we can stop nuclear tests by doing this, but we were consistent in our belief that we must show Hiroshima’s anger to the world through this non-violent campaign,” said Yukio Yokohara, 73, voicing Mr. Moritaki’s thoughts. Mr. Yokohara is a member of the board of directors of the Hiroshima chapter of the Japan Congress Against A- and H-bombs (Gensuikin).

The City of Hiroshima sent its first letter of protest to French President Charles de Gaulle in September 1968, after France conducted a hydrogen bomb test. Hiroshima has sent a total of 607 letters of protest to eight nations, including 243 to the United States and 188 to Russia and the former Soviet Union. Reduced copies of these letters were displayed in the East Building of Hiroshima Peace Memorial Museum, with the idea of sharing Hiroshima’s convictions with visitors from around the world. The building has been closed for renovations since September 2014, and digital versions of the letters will be shown after the building reopens.

After the Partial Test Ban Treaty (PTBT) was signed by the United States, the former Soviet Union, and the United Kingdom in 1963, many of the following nuclear tests were conducted underground. Nuclear powers that are signatories of the Nuclear Non-proliferation Treaty (NPT), the United States, Russia, the United Kingdom, France, and China, have refrained from carrying out experiments that involve denotations since the 1990s.

Divide between the A-bombed cites and the Japanese government

Hiroshima and Nagasaki have been protesting North Korea’s underground tests, the U.S. subcritical tests that do not involve explosions, and that nation’s plutonium experiments using the Z machine. The A-bombed cities regard those tests as “an expression of their intent to keep nuclear weapons.”

Meanwhile, the Japanese government has held a wait-and-see attitude toward such tests. Wishing to maintain the protection afforded by the U.S. nuclear umbrella, the government says these tests are “intended to ensure the safety and effectiveness of nuclear weapons, and do not involve nuclear explosions.” It is quite clear that the city governments of Hiroshima and Nagasaki view this issue with more serious concern than Japan’s national government.



Sandia National Laboratories
The Sandia National Laboratories are under the jurisdiction of the U.S. Department of Energy’s NNSA. Other national facilities are the Los Alamos National Laboratory located in New Mexico and the Lawrence Livermore National Laboratory in California. The Sandia, which was established in 1948, is located at Kirtland Air Force Base in central New Mexico. The base is believed to have a storage facility for nuclear warheads. The laboratories are operated and managed by a subsidiary of Lockheed Martin Corporation, and conduct extensive research on the non-proliferation of weapons of mass destruction and environmental technology.

Comprehensive Test Ban Treaty (CTBT)
The CTBT, which bans all nuclear tests that produce a nuclear explosion, was adopted at the United Nations General Assembly in 1996. As of December 2014, out of the 183 nations that have signed the treaty, 163 have ratified it. For the treaty to come into force, all 44 nations that have nuclear reactors either for conducting research or generating electricity must ratify it. Of these 44 nations, the United States, China, Egypt, Iran, and Israel have not ratified it. North Korea, India, and Pakistan have not signed it. The United States, Russia and the United Kingdom continue to conduct subcritical tests, arguing that they do not involve detonations.

Chronology of the nuclear arms race

October 1941
U.S. President Franklin Roosevelt orders development of atomic bombs. The Manhattan Project is launched the following year.

July 1945
The world’s first atomic bomb test is conducted at the Trinity Site in the U.S. state of New Mexico.

August 1945
Hiroshima and Nagasaki are attacked with atomic bombs.

July 1946
The U.S. conducts the first postwar atomic bomb test at Bikini Atoll in the Marshall Islands.

August 1949
The Soviet Union conducts its first atomic bomb test at Semipalatinsk (now Kazakhstan), breaking the U.S. monopoly on nuclear weapons. The nuclear arms race begins.

October 1952
The U.K. conducts its first atomic bomb test in the Montebello Islands, Western Australia.

November 1952
The U.S. conducts its first hydrogen bomb test in the Marshall Islands.

March 1954
The U.S. carries out a large hydrogen bomb test at Bikini Atoll. Twenty-three crew members of the Daigo Fukuryu Maru (Lucky Dragon No. 5) are exposed to radioactive fallout. The movement against atomic and hydrogen bomb tests and ban-the-bomb signature drives gains unprecedented momentum in Japan.

September 1954
Aikichi Kuboyama, the chief radio operator of the Daigo Fukuryu Maru, dies from radiation sickness.

August 1955
The first meeting of the World Conference Against Atomic and Hydrogen Bombs is held in Hiroshima.

November 1955
The Soviet Union conducts its first hydrogen bomb test at Semipalatinsk.

March 1957
Kiyoshi Kikkawa, “Atomic bomb victim No. 1,” and others stage the first sit-in in front of the Cenotaph for the A-bomb Victims, protesting the U.K. hydrogen bomb test plan.

May 1957
The U.K conducts a hydrogen bomb test at Christmas Island, located in the Pacific.

February 1960
France conducts an atomic bomb test in the Sahara Desert, Algeria.

October 1961
The Soviet Union conducts the world’s largest nuclear test. The explosive power of the bomb is 50 megatons, more than 3,000 times as great as that of the atomic bomb dropped on Hiroshima.

April 1962
Protesting the U.S. atmospheric nuclear test plan, Ichiro Moritaki and others stage a sit-in in front of the Cenotaph for the A-bomb Victims.

October 1962
The Cuban missile crisis flares. Tensions between the U.S. and the Soviet Union escalate.

August 1963
The U.S., the Soviet Union, and the U.K. sign the Partial Test Ban Treaty (PTBT), bringing a stop to atmospheric nuclear tests.

October 1964
China conducts an atomic bomb test at Lop Nor, China.

July 1968
The signing ceremony of the review conference of the Nuclear Non-proliferation Treaty (NPT) is held.

August 1968
France conducts a hydrogen bomb test.

September 1968
The City of Hiroshima sends its first letter of protest to France, following the hydrogen bomb test.

March 1970
The NPT comes into force.

July 1973
The two factions of the Hiroshima Prefectural Confederation of A-bomb Sufferers Organizations and other groups conduct a sit-in to protest France’s nuclear test plan.

May 1974
India conducts a nuclear test, calling it a “peaceful nuclear explosion.”

October 1990
The Soviet Union conducts a nuclear test. After this, it suspends tests which involve explosions.

August 1991
The Soviet Union announces the closure of the nuclear test site at Semipalatinsk.

December 1991
The Soviet Union is dissolved.

September 1992
The U.S. conducts its 1,032nd underground test. After this, it suspends tests which involve explosions.

January 1996
France conducts a nuclear test. President Jacques Chirac declares a halt to its nuclear testing.

July 1996
China carries out a nuclear test. China announces a freeze on nuclear tests.

September 1996
The Comprehensive Test Ban Treaty (CTBT) is adopted at the United Nations General Assembly.

July 1997
The U.S. conducts its first subcritical nuclear experiment in Nevada.

May 1998
India conducts two underground tests. Pakistan carries out its first nuclear test.

October 1999
The U.S. Senate votes against CTBT ratification.

October 2006
North Korea conducts an underground nuclear test.

May 2009
North Korea conducts its second nuclear test.

September 2010
The U.S. conducts a subcritical experiment, the first such test under the Obama administration.

November 2010
A new type of nuclear test, using a small amount of plutonium, is conducted with the Z machine at Sandia National Laboratories.

February 2013
North Korea conducts its third nuclear test.

(Originally published on December 22, 2014)