Tuesday, April 9, 2002 202-822-8444;


Opposition Leader Ozawas Statement is Technically Accurate,
Politically Dangerous, Says Nuclear Control Institute

WASHINGTON---Japanese Liberal Party leader Ichiro Ozawas recent statement that Japan could easily produce thousands of nuclear warheads using plutonium recovered from the spent fuel of its commercial nuclear power reactors is technically accurate, the Nuclear Control Institute (NCI) confirmed today. 

Ozawa stated in a lecture delivered Saturday that if [China] gets too inflated, Japanese people will get hysterical. It would be so easy for us to produce nuclear warheadswe have plutonium at nuclear power plants in Japan, enough to make several thousand such warheads.
[I]f we get serious, we will never be beaten in terms of military power. His remarks were widely reported in the Japanese press. 

Ozawas nuclear threat would be an extraordinarily dangerous policy for Japan, abandoning Japanese rejection of nuclear weapons under the Nuclear Non-Proliferation Treaty, and it could destabilize all of Northeast Asia," said Dr. Edwin Lyman, scientific director and soon-to-be president of NCI, a non-proliferation research and advocacy center. However, it is important to note that on a technical level, Ozawa is absolutely correct. Despite deliberately misleading claims by plutonium-fuel advocates in Japans nuclear power industry, the plutonium separated from spent nuclear fuel by means of reprocessing---so-called reactor-grade plutonium---can indeed be used to build reliable nuclear weapons with enormous explosive yield.

Japan currently possesses some 38 tons of reactor-grade plutonium, of which 5 tons is stored in Japan and the rest in France and Great Britain, where Cogema and BNFL (the state-owned French and British reprocessing corporations) separated the material from Japanese spent fuel. The Japanese government says it intends to use the plutonium in reactors as mixed-oxide, plutonium-uranium fuel (known as MOX or pluthermal fuel). However, Japans plutonium fuel program has been hit with numerous difficulties, including runaway costs, multiple accidents and public rejection of introducing highly toxic MOX fuel in reactors. The result has been an enormous surplus of Japanese separated plutonium building up over the last decade. 

Japans plutonium program is simply unnecessary for meeting its energy-security needs because of an abundance of cheap, readily available and non-weapons-usable uranium fuel, noted Paul Leventhal, NCIs president, who will retire and become president emeritus on June 1. Japans accumulation of plutonium is already viewed as a threat by its neighbors in the region, including both Koreas and China. Ozawas claim that Japan could build thousands of nuclear bombs from its reactor-grade plutonium is as politically dangerous as it is technically correct. The best way for Japan to reassure its neighbors of its peaceful intentions is not to plead that its plutonium is innocent, but to halt the commercial plutonium program and to dispose of the separated plutonium by immobilizing it in highly radioactive waste. 

On March 27, NCI hosted a seminar on Japan, Nuclear Weapons and Reactor-Grade Plutonium, at which Dr. Marvin Miller, MIT senior scientist emeritus, concluded that Japan is at least at the intermediate point, and most probably at the high end of the weapons capability spectrum. While not implying and having no knowledge of a clandestine Japanese nuclear weapons program, Miller found that the competence of their scientists in related applications indicates that they could make advanced weapons using reactor-grade plutonium if the political decision is made to go ahead. He concluded: In my judgment, the nuclear weapon states, particularly the United States, should strive to keep Japan as far as possible from the need to seriously consider this issue.At the same time, safeguards and physical security on all existing weapons-usable materials, including reactor-grade plutonium, need to be upgraded and their stocks decreased. 

Over the past two decades, Japanese plutonium advocates have raised suspicions by making numerous false or misleading claims about the weapons potential of reactor-grade plutonium. Nearly a decade ago, Ryukichi Imai, former Japanese ambassador for non-proliferation, wrote that the reactor-grade plutonium shipped from France to Japan "is quite unfit to make a bomb." That same year, Hiroyoshi Kurihara, former executive director of PNC (then Japans primary company for developing plutonium-fueled reactors) stated that "many Japanese experts express the opinion that reactor-grade plutonium could not be used for workable nuclear weapons." He speculated it "can be merely a nuclear fireworks, namely it produces glare and a big noise, but would not cause big disastrous effects of nuclear bombs...." Such a weapon, he said, would "fizzle like a firecracker." In 1994, PNC distributed a video in which "Pluto Boy," a cartoon character representing plutonium, reassures the audience that a workable bomb cannot really be made from reactor-grade plutonium. PNC was dissolved in 2000 in the wake of the disastrous nuclear criticality accident, killing three workers, at its Tokai-mura facility where fuel was being prepared for its Joyo experimental plutonium breeder reactor. 

Despite Japanese denials, the ability to construct a weapon from plutonium separated from the spent fuel of nuclear power plants was settled long ago. In 1976, the U.S. government first declassified the information that reactor-grade plutonium could be used to make weapons and could even be the basis for a national military program. The following year, it declassified the fact that the United States successfully detonated a nuclear bomb made from reactor-grade plutonium at the Nevada Test Site in 1962. In 1990, Hans Blix, then the director-general of the International Atomic Energy Agency (IAEA), reversed the agencys position on reactor-grade plutonium and acknowledged to the Nuclear Control Institute that there is "no debate" at the IAEA that virtually all isotopes of plutonium, including those that comprise reactor-grade plutonium, are usable in nuclear weapons. The U.S. Department of Energys current guidance states that nuclear weapons of all levels of sophistication can be made from reactor-grade plutonium and that proliferating states using designs of intermediate sophistication could produce weapons with assured yields substantially higher than the kiloton-range possible with a simple, first generation nuclear device. 

More information about Japans plutonium program is available on NCIs website at