Japan’s Plutonium Problem

Liu Chong

More than one month ago, Japan's Kyodo News reported that the United States has been pressing Japan to return 331 kg of mostly weapon-grade plutonium that was received from the United States and Britain for fast reactor research during the Cold War.

Despite this recent attention, in actuality, Washington has been urging Tokyo to return the nuclear materials as soon as possible since at least the Washington Nuclear Security Summit in 2010. However, Japan has been reluctant to comply, claiming that the plutonium has been used in fuel assemblies in its research. Only recently did the Japanese Government attempt a bargain before the Hague Nuclear Security Summit, scheduled for March 24-25, with the United States on the issue.

In his speech in Prague in 2009, US President Barack Obama announced a goal to secure all vulnerable nuclear materials around the world within four years. The Obama administration's resolution that Japan must return the plutonium is aimed at integrating the issue into the process of the Nuclear Security Summit.

Plutonium and highly enriched uranium are the basic materials needed to build a nuclear bomb. Highly enriched uranium can be relatively easily used to make gun-type nuclear weapons while plutonium can be used to make more sophisticated imploson-type nuclear weapons. Highly enriched uranium is widely used in scientific research and isotope production; thus, many non-nuclear-weapon states have a limited supply for such purposes. But since plutonium needs to be exacted from spent fuel, few countries own separated plutonium for civilian use.

For the above reasons, the reduction measures proposed by the first two nuclear security summits mainly focused on highly enriched uranium for civilian purposes, such as converting reactors from using highly enriched uranium fuel to using low-enriched uranium and voluntarily returning the highly enriched uranium. Thus far, those measures have been well implemented and much progress has been made in reducing highly enriched uranium. Against this backdrop, the United States wants all countries to reduce their surplus separated civilian plutonium gradually after the Hague Nuclear Security Summit following the highly enriched uranium reduction mode. Washington's urging Japan to return of plutonium also aimed to make Japan an example for other countries.

The key topic of nuclear security summits is, predictably, keeping nuclear materials out of terrorists' hands. For Japan, the international community worries that the country might produce nuclear weapons and damage the international nuclear nonproliferation regime. Kyodo News cited an unnamed insider of the Abe cabinet as saying that Japan's agreeing to return the plutonium is intended to eliminate international concerns on Japan's military expansion. However, the approximate amount of 300 kg separated plutonium exported to Japan is merely a drop in the bucket of Japan's own separated plutonium storage. Given Japan's strong capacity for nuclear enrichment and reprocessing as well as the growing right-wing support for Japan to produce its own nuclear weapons, Japan must do more to win the trust of the international community.

Japan is the only non-nuclear country that owns a large quantity of separated civilian plutonium. For many years, under the guise of fast reactor research, it produced plutonium after purchasing reprocessing services from Britain and France. By the end of 2011, Japan had produced 44.3 tons of separated plutonium, among which 9.3 tons are stored within Japan while the rest is deposited in Britain and France.

Due to differences in the burn up of nuclear fuel in the reactor, the percentages of the isotope plutonium-240 in the plutonium extracted differ. Plutonium is graded as either reactor-grade or weapon-grade depending on the percentage of the isotope plutonium-240. Currently, the plutonium Japan possesses is mainly reactor-grade one. However, US tests in the 1960s showed that any grade of plutonium can be used to make nuclear weapons. In addition, Japan's advanced technology means it is likely able to produce nuclear weapons with reactor grade plutonium. Therefore, the international community is still doubtful of the intentions behind Japan's large plutonium stockpile.

In 1997, Japan issued a written commitment to the International Atomic Energy Agency (IAEA) that all its separated plutonium would be used in reactors and no amount of surplus materials would be accumulated. At first Japan hoped to use the separated plutonium for fast reactor purposes, but frequent accidents at its Monju fast reactor halted the effort. Its commercial fast reactor project is also unfeasible. Thus, Japan transformed part of its plutonium into mixed oxide fuel used in light-water reactors to show the commercial value of its separated plutonium. However, this project is also not going so well.

After the Fukushima nuclear accident in 2011, there have been waves of anti-nuclear demonstrations in Japan. Many of the country's nuclear power plants have been closed, making the development of a fast reactor more difficult with its nuclear power policy shelved, it is more difficult for Japan to justify its vast amount of plutonium storage. Japan's commitment to the IAEA appears to be an empty promise.

Of greater concern to the international community is that Japan has long been committed to advancing its nuclear fuel cycle technologies. Moreover, it is the only non-nuclear-weapon country with production capacity and facilities for enriched uranium as well as plutonium. If the facilities at Japan's Rokkasho nuclear-reprocessing plant are all used to produce highly enriched uranium, its annual production volume could reach 6.4 tons. It is therefore necessary to ensure that the plant falls under IAEA inspections and produces only low-enriched uranium for reactors.

In addition, Japan's decision to build a nuclear-reprocessing plant in Rokkasho has worried the world. By purchasing reprocessing services from Britain and France, Japan has already stored a great amount of separated plttonium. But the Japanese Government still insists on building its own nuclear-reprocessing plant with a total investment of $21 billion. The full capacity of the Rokkasho nuclear-reprocessing plant is projected to reach 9 tons of separated plutonium annually, equivalent to the total current separated plutonium storage of Japan. This large amount of plutonium could be used to make about 2,000 nuclear bombs every year. Without a clear plan for the peaceful use of plutonium, Japan continues to strengthen its reprocessing capacity. There is reason to believe that Japan intends to enhance its nuclear weapon latency.

The Japanese Government introduced the "three non-nuclear principles" in 1967, stating that Japan will not produce, possess or allow the entry of nuclear weapons. These principles and its pacifist Constitution have become the cornerstones of Japan's post-World War II development. However, in recent years, calls for acquiring nuclear capability in Japan have gradually grown. The attitudes of its top officials toward its nuclear policy are especially worrying.

In 1994, then Japanese Prime Minister Tsutomu Hata declared that Japan has the capability to possess nuclear weapons. In May 2002, then Prime Minister Junichiro Koizumi affirmed that Japan would adhere to the three non-nuclear principles, but added that the country did possess the technology to make nuclear weapons. Then Deputy Chief Cabinet Secretary and current Prime Minister Shinzo Abe even said, "Undoubtedly, Japan will have small atomic bombs in the future." This alarming statement coupled with the increasingly right-wing atmosphere in Japan, is bound to create uneasiness in the international community.

In sum, Japan on the surface actively promotes the three non-nuclear principles and is willing to accept IAEA guidelines; at the same time, however, it is trying to construct a complete nuclear technology system relevant to nuclear weapon production at great expense under the cover of developing nuclear power. Japan has also developed solid-propellant rocket technology, laying a foundation for making long-range missiles to deliver nuclear warheads. With these steps, it has been publicly recog-nized as a nuclear-hedging country.
After returning the separated plutonium to the United States, the Japanese Government should take further measures to postpone starting its Rokkasho nuclear reprocessing plant. It should also make concrete plans to gradually eliminate the surplus separated plutonium stor-age at home, and subject itself to international verification. Only by taking these steps can Japan earn the trust of the international community through actions rather than rhetoric.
[source: Beijing Review, March 20, 2014]

Frontier
Vol. 46, No. 49, Jun 15 - 21, 2014