International Meeting
2003 World Conference against A & H Bombs

Kim Seung-Kuk
Peace activist of South Korea



North Korean nuclear crisis has cropped up again since October last year after it was first patched up by US-North Korea Agreed Framework( Geneva agreement) in 1994. The first crisis of 1993 to 1994, which almost brought a war to the Korean peninsula, was
a conflict over Pyongyang's alleged use of enriched plutonium for nuclear weapons.

After signing the 1994 agreement, however, the Uniterd States has started to provoke Pyongyang by violating the agreement with North. The current second crisis started with the rows over the " North Korea's admission of a nuclear program by uranium enrichment" after the U.S. envoy James A. Kelly visited the North in October last year. During his visit, Kelly pressed hard Pyongyang side alleging that Pyongyang has a nuclear weapons program by enriching uranium. To this,

Pyongyang countered that "it is entitled to have nuclear programs for self defense if Washington continues hostile policy toward it, but, at present stage, it only wants to pursue peaceful use of nuclear materials, namely, electric-power production."

The Pyongyang's current nuclear crisis has aggravated by the U.S.'s suspension of fuel oil shipments to the North promised under the 1994 accord. In retaliation to this suspension, Pyongyang removed IAEA seals and monitoring cameras from its Yongbyon nuclear facilities and withdrew from the Nuclear Nonproliferation Treaty(NPT), thus reversing Pyongyang-Washington relations to the pre-1994 lowest level.

We are not sure whether the current crisis will take the course of the previous crisis which was tided over by the 1994 agreement just before the possible outbreak of a war.

To resolve the current nuclear crisis, worsened by the North's pulling out of the NPT, it will be necessary for the U.S. to give Pyongyang a security guarantee, possibly through a nonaggression pact as demanded by Pyongyang. If Washington rejects this earnest demand of Pyongyang, the current crisis may again escalate to the brink of a war, as did the previous one.

If we want to resolve wisely the current crisis peacefully, we have to understand the truth of North Korean nuclear issue, as well as the basic reason for Pyongyang's taking such drastic measures as its withdrawal from the NPT.

Summary of North Korean nuclear crisis

1. Settlement of North Korean nuclear crisis in 1994

1) 1994 North Korean nuclear crisis:

As North Korea acceded to the NPT in December 1985 and subsequently signed its safeguards agreement in January 1992, the International Atomic Energy Agency(IAEA) conducted six rounds ofprovisional and general inspection on Pyongyang's nuclear facilities from May 1992 to February 1993. In these inspections, IAEA found a major discrepancy between what it found and what the North initially declared to it.

Especially, the IAEA demanded a special inspection on two undeclared facilities, assuming they were nuclear waste sites. But Pyongyang refused this demand, alleging they were military facilities, and on March 12,1993 announced to withdraw from the NPT, making Pyongyang's nuclear issue an international concern.

Eventually, Washington and Pyongyang entered into negotiations from June 1993 to October 1994, and U.S. Ambassador Calluchi and North Korean First Deputy Foreign Minister Kang Suk-joo signed the Agreed Framework(Geneva agreement) in October 1994, ending the Pyongyang's first nuclear crisis.

2) North Korea-U.S. Agreed Framework

(1) Freezing and eventual dismantling of Pyongyang's graphite-moderated nuclear reactor, and building light-water nuclear reactors for Pyongyang:

Under the 1994 agreement, the United States pledged to build two light-water nuclear reactors(2,000MW) for North Korea by 2003 through an international consortium. It also commited to provide the North with heavy oil until the completion of one reactor, in compensation for Pyngyang's expected loss of energy by the freezing of its graphite-moderated nuclear reactor. For these purposes, Korean Peninsula Energy Development Organization(KEDO) was set up.

(2) Full normalization of political, economic relations between Washington and Pyongyang:

The United States pledged to relax trade and investment restrictions imposed on the North within three months, including restrictions on telecommunication and financial transactions. Both sides also agreed to establish liason offices in each other's capital, and elevate their relationship to an ambassadorial level as they make progress in settling their bilateral issues.

(3) Denuclearization of Korean peninsula:

The United States pledged not to use, or threaten to use, nuclear weapons against Pyongyang, while Pyongyang undertook to pursue implementation of the South-North Joint Declaration for Denuclearization of Korean peninsula. It also agreed to start inter-Korean dialogue.

3. Argument about plutonium: The case of 1994 North Korean nuclear crisis

When uranium(U238) absorbs neutron, it turns into Pu239. And when a nuclear reactor is activated for a fixed period, Pu239 is accumulated.

The accumulated(produced) amount of Pu varies with heat output and operation period of the reactor, but, in the case of ordinary light-water reactors, about 1 percent of spent fuel is Pu. Graphite-moderated reactor produces less amount of Pu than pressured light-water reactors, but its Pu is higher in concentration.

Reprocessing means chemically extracting effective elements(mainly Pu) remained in spent nuclear fuel. Spent nuclear fuel is a high-level radioactive material. Especially, since Pu is radioactive material, its reprocessing requires special protective facilities such as hot cell, glove box.

Recently, as North Korea removed IAEA seals from its nuclear facilities, it was feared that Pyongyang might convert its existing enriched plutonium stock to nuclear-weapons production. But it is not to worry about at all. Though it is basically easy to reprocess plutonium, it is doubtful that Pyongyang can produce nuclear weapons even if it operates all its nuclear facilities.

4. Assessment of North Korean nuclear facilities

North Korean nuclear facilities frozen under the 1994 US-North Korean Agreed Framework are as follows:

5-megawatt reactor at Yongbyon( Its operation suspended);
50-megawatt reactor at Yongbyon and 200-megawatt reactor at Taechon, which were scheduled to be completed in 1995 and 1996 respectively( their construction suspended);
Radiochemistry laboratory at Yongbyon that can reprocess spent fuel for plutonium(Its operation suspended);
About 8,000 spent fuel rods extracted from the 5-megawatt reactor (stored in 360 containers and sealed)

The United States, the IAEA and media around the world suspect that Pyongyang may produce nuclear bombs from the above-listed facilities. But, it is important to know the truth, before trying to find any solution to the North Korean nuclear crisis.
First of all, we should clearly understand that North Korea, which basically seeks a self-reliant economy, has constructed its nuclear facilities to complete a cycle of nuclear power generation to achieve self-sufficiency in energy. We should not overlook that Pyongyang planned to build a self-reliant nuclear power generation complex at Yongbyon by using abundant uranium resources in the country. Then, let's see details of its nuclear facilities.

1) 5-megawatt nuclear reactor

This reactor is an experimental reactor for power generation, capable of producing both electric power and plutonium. Britain first operated it in 1956. But its efficiency is very low. Then, why Pyongyang sticked to this one?

(1) The details of this reactor are well known in the world, and Pyongyang can easily learn them.

(2) It uses natural uranium as fuel, which is abundant in the North

(3) It uses CO2 as coolant that can easily be obtained.

(4) North Korea has moderator.

(5) North Korea can build nuclear weapons with this reactor without so much know-how. It has a lower commercial merit but can be operated cheaply. Compared with a light-water reactor, it can enrich more easily, and enriched uranium concentration is higher. Reprocessing is easy. Therefore, Pyongyang can produce weapons-grade enriched uranium economically, using its own natural resources.

Pyongyang seems to have chosen this model because of the above reasons.

Nevertheless, this 5-megawatt reactor also has the following drawbacks.

(1) Magnesium is easily oxidized(corroded)

(2) Its thermal efficiency is low.

(3) It has a safety problem.

* North Korea should have worried that the 8,000 spent fuel rods produced by this reactor could corrode in several years. Although these rods have been sealed by the IAEA, one reason why the North has taken them out may be to check whether they have been corroded.

* There are cooling towers attached to this reactor, which are for power generation, not for exclusive weapons production.

* While the reactor is in operation, the cooling tower emits water vapor like smoke. If smoke is not seen, the reactor is supposed to have been temporarily shut down for reprocessing purpose. The U.S. and the IAEA pressed the North hard by saying that "There has been no smoke from cooling towers for the past 70 days. You must have reprocessed spent fuel during this period, haven't you? " To this, the North admitted having reprocessed 90 grams. But an issue has been made by the IAEA confirming several kilograms of plutonium in the North through its post-Agreed Framework inspections( the issue of 'past nukes').

2) Construction of a 50-megawatt reactor at Yongbyon has been suspended.
3) Construction of 200-megawatt reactor at Taechon has been suspended.

(4) Strengthening of NPT regime:

North Korea agreed to remain a party to the NPT and allow IAEA inspections under the safeguards agreement with it. It also agreed to allow provisional and general inspections on its unfrozen facilities following negotiations with the IAEA.

2. Differences between Pyongyang and Washington

1) Statement of U.S. State Department

The main part of the statement that touched off the North Korean nuclear crisis after the visit to Pyongyang of U.S. envoy James Kelly is as follows;

"The U.S. delegation led by James Kelly, the U.S. Assistant Secretary of State, conveyed to the Northern side that the U.S. had recently obtained intelligence report showing Pyongyang's possession of an uranium enrichment program for nuclear weapons production, in violation of such nuclear agreements as the 1944 Agreed Framework with the United States. Pyongyang side acknowledged possession of a nuclear weapons program. Pyongyang's clandestine nuclear weapons program constitutes a grave violation of the Agreed Framework, the NPT, the agreements with the IAEA and the South-North Joint Declaration for Denuclearization of Korean peninsula". It seems that Pyongyang, in response to the hard pressing of Kelly, countered that "if America continues to stifle Pyongyang, it is also entitled to have a nuclear weapons program".

2) North Korean argument

Pyongyang countered that " In response to an increasing nuclear threat from the U.S. to us, we made it clear to Kelly that North Korea, in order to defend its independence and the right to existence, can have not only nuclear weapons but also even more powerful ones"

3. Main arguments

Then, we are now going to raise basic questions for the solution of North Korean nuclear crisis.

The first North Korean nuclear crisis from 1993 to 1994 started with suspicion about the North's plutonium-producing facility, but this crisis was settled diplomatically. The immediate cause of the current second crisis was the U.S. pressing Pyongyang hard about its uranium enrichment program and Pyongyang's's acknowledgement of it. But its more important cause was the mutual distrust resulting from the delay or default in the implementation of the 1994 accord. Speculation and exaggeration about the crisis also have amplified the crisis.

Does North Korea really have a uranium-enrichment program?

If it does, how effective the program is?

What is(or was, will be) the possibility of Pyongyang's producing plutonium-based nuclear bombs?

Does Pyongyang possess nuclear weapons now?

What is the position of Pyongyang on its nuclear issue?

Scientific and Technological understanding of North Korean nuclear issue

1. Raw materials of nuclear bombs: Enriched uranium vs. plutonium

While the first North Korean nuclear crisis concerned enriched plutonium, the current crisis centers on uranium enrichment. Then, by what processes can these two materials make nuclear bombs?

The main materials that can be used for nuclear weapons or for atomic power generation through chain nuclear fission are U235 and Pu239. Natural uranium contains only 0.71 percent of U235, so it has to be enriched to over 90 percent to become weapons-grade.

On the other hand, plutonium(Pu 239) is an artificial element produced by reacting U238 to neutron, and can be produced only by activating a nuclear reactor. Enriched plutonium can be extracted by reprocessing spent nuclear fuel. Basically, enriching plutonium is done by chemical process and is easier than uranium enrichment done by physical process.

There are two types of atomic bombs: Gun-type and Implosion-type.

Plutonium Pu239 cannot make Gun-type bombs, whereas uranium 235 bombs are easy to make and can be combat-deployed without prior explosion test.

Although minimum critical mass for nuclear explosion varies with their concentration, roughly it is less than 1kg for uranium and about 300 grams for plutonium. But several ten times of these quantities are required to produce a nuclear bomb of proper size.

So, even though enriching uranium235 is processed by physical method, it is very difficult and troublesome. But Pu239 can be produced only in a reactor, but can easily be processed chemically.

Then, how much enriched uranium or plutonium North Korea will require to build one nuclear bomb?

(1) At present, Pyongyang's capacity for developing nuclear weapons is assessed on the basis of those atomic bombs dropped on Hiroshima and Nagasaki,Japan in 1945. The "Little Boy" uranium bomb dropped on Hiroshima was loaded with 70%-enriched, 140-pound uranium. The "Fat Man" plutonium bomb dropped on Nagasaki was loaded with 130 pounds of highly enriched plutonium.

(2) But only 1.38 percent of "Little Boy" weighing 65 kilograms could produce nuclear explosion.

Judging from those data, we can make one uranium bomb with 15-30 kilograms of enriched U235. Also, if we consider that, out of the Fat Man weighing 6 kilograms, only one gram succeeded in nuclear fission and produced nuclear explosion, more than 9 kilograms of Pu239-- namely, 30 times of 300 grams of minimum critical mass--- is needed to make one plutonium bomb.

However, the required amount of U235 and Pu239 varies with the know-how of nuclear weapons production. For instance, the United States can make a plutonium bomb with 15 kilograms of Pu239, as it has acquired much know-how by conducting over 5000 times of nuclear test.

But North Korea, with little experiences of nuclear weapons production, may require at least 30 kilograms of Pu 239 for one plutonium bomb. Moreover, allowing an expected loss during production, Pyongyang may need 50 kilograms of Pu239 for one plutonium bomb..

Then, it is a very important question whether Pyongyang possesses 50 kilograms of Pu239. There has been much speculation about Pyongyang's possession of plutonium, but there has been almost no talk of its possessing so much as 50 kilograms of Pu239. This makes the augument that Pyongyang can build plutonium bomb questionable..

2. Uranium enrichment and plutonium extraction

1) Enriching uranium

(1) Gas diffusion method

This method is based on the principle that, when UF6 gas is diffused through a separation wall having many micro-pores, more of lighter isotope(U235) passes through the wall. At this time, 2,300-2,500kWh/SWU of electricity is consumed. To obtain highly enriched uranium of more than 90% concentration, over 3,000 diffusion stages are necessary. At present, there is no country in the world that uses this method.

North Korea has to use this method if it intends to develop nuclear weapons through uranium enrichment. But Pyongyang has the following difficulties for that.

(a) As already said, it takes more than 3000 diffusion stages to get highly-enriched uranium of 90% concentration. Can Pyongyang get through with these highly difficult stages without being detected by the U.S. or I.A.E.A.?

(b) Gas diffusion method requires enormous amount of electricity, may be even more than that Pyongyang produces. Can the country that is now critically short of electricity afford so much electricity for uranium enrichment? The U.S. and the IAEA will easily detect Pyongyang's undertaking this method and block it immediately. Producing one plutonium bomb is said to cost about 1.2 billion dollars in America. Can Pyongyang meet this cost? Therefore, even if Pyongyang may have a uranium-bomb program, it is doubtful that it can be effective.

(2) Method of gas centrifuge:

In this method, a cylinder containing UF6 gas is rotated at ultra-high speed so that heavier U238 is pushed toward the cylinder wall while lighter U235 is pulled toward the center of the cylinder.

Electric consumption amounts to 50kWh/SWU. South Korea has adopted this method.

(3) Method of laser isotope separation:

This method is to irradiate a laser beam that can only be absorbed by U235 atoms, and pass the filtered (+)U235 atoms through magnetic field, and then deposit (+)U235 ion onto the (-)electrode.

This method consumes enormous amount of electricity, so it has not yet been commercialized. It is therefore absurd to say that Pyongyang is going to develop nuclear weapons by this laser method.

2) Centrifugal separating capacity of a centrifuge of 1-2 meters in height and 20 centimeters in diameter per year is about 5 SWU. This one centrifuge can produce about 30 grams of weapons-grade uranium by using about 250kWh of electricity. Therefore, about 30 kilograms can be extracted by operating 1,000 centrifuges for one year. Pakistan could extract about 60 kilograms of uranium by operating 2,000-plus centrifuges. On this basis, let's figure out the possibility of North Korea's developing nuclear weapons.

(1) As pointed out earlier, allowing the expected loss, 50 kilograms of U235 will be needed. But it will be very difficult for the North to produce 50 kilograms of U235 for the following reasons:

a) In view of the critical shortage of electricity in the North, it cannot ensure a stable and continuous supply of enormous amount of electricity needed.

b) Centrifuges are enormously expensive and their traffic is closely monitored by the IAEA, so it is very difficult to introduce them secretly. According to the U.S. C.I.A., Pyongyang secretly brought 100 centrifuges from Pakistan hidden in caskets. Could that be possible? Britain's 'The Times' even reported that "With centrifuges it has introduced, Pyongyang can produce 10 kilograms of U235 and can build nuclear bombs within three months". This is a typical case of exaggeration.

Pyongyang has to buy at least 1,000 centrifuges abroad to produce atomic bombs. It will take enormous space and electricity to operate 1,000 centrifuges. It can produce one atomic bomb by operating 1,000 centrifuges for several years, using all of its domestic power supply. Thus, even though Pyongyang mat have a nuclear program, it will be very difficult for it to produce nuclear bombs.

Therefore, the current fuss over North Korean nuclear issue (alleged development of uranium-based nuclear weapons) is likely to turn out the second version of 'Kumchang-ri incident'. As American nuclear inspectors found only an empty cave in Kumchang-ri in North Korea, Unites States seems to be pursuing only a 'phantom' of Pyongyang's 'nuclear-weapons program'. So, if the United States and the IAEA again find nothing of North Korea's 'uranium-based nuclear program' they are playing into the hands of Pyongyang's highly psychological warfare strategy of NCND(No confirm, no deny).

4) Radiochemical laboratory:

This is the second largest reprocessing facility after the Hanford facilities, and is suspected of reprocessing spent fuel. However, it is doubtful that it is for nuclear weapons production because it does not have a nuclear waste processing facility. Though this laboratory has a large capacity, there is no knowing how long it will take before it can be operated at all. (At present, 70 percent of facility has been completed, but it will take considerable time to put it into operation). It is absurd to say that this facility can produce tens of nuclear weapons a year even though there is no waste processing facility.

Also, reprocessing spent fuel produces very high-level radioactivity, and careless reprocessing causes a disaster. Will North Korea take this risk to build nuclear weapons?

Furthermore, it is impossible to operate this laboratory before it is fully equipped. Even after the system is completed, a long period of experiment is needed to build nuclear weapons. So it is groundless to say that Pyongyang can build nuclear weapons very soon.

The 'glow box', the reprocessing facility of this laboratory, is no bigger than those used in university labs. So it is unbelievable that the second largest reprocessing facility in the world would reprocess spent fuel using "toy-like" vessels . In the nuclear power stations in South Korea, robot arms are used in the hot cell to handle radioactive materials. So it is questionable that Pyongyang can efficienly reprocess by manual vessels.

As for the plutonium enrichment, it is impossible for a country to hide its history of reprocessing spent fuel, as long as the country is a party to the NPT and subject to inspections of the IAEA. The IAEA can trace the whole repressing history and calculate the amount of enriched plutonium. That is why the U.S. does not worry about Pyongyang's plutonium enrichment. Thus, North Korea cannot build nuclear weapons as long as it is acceding to the NPT.

Are North Korean nuclear facilities for nuclear weapons production?

The fundamental idea of Pyongyang's building nuclear facilities is not for building nuclear weapons but for the completion of nuclear cycle(nuclear power generation cycle). To support this viewpoint, the following are emphasized:

1) North Korea has 26 million tons of high-quality natural uranium reserves. Unlike South Korea, Pyongyang from the start has had a whole chain system relating to nuclear power generation( including facilities for reprocessing spent fuel as well as waste disposal).

2) North Korea must have planned for a self-reliant energy system in accordance with its "Juche" self-reliance ideology. For this, it must have built nuclear power generation complex(facilities for nuclear power generation cycle), by using its high-quality uranium.

However, under the 1994 Framework Agreement, Pyongyang froze this nuclear complex at Yongbyon in exchange for U.S. commitments to Pyongyang, including construction of two light-water reactors. But the U.S. defaulted on its major commitments under the agreement.

Washington has continued to undermine North Korean regime by refusing a security guarantee to it. Construction of light-water reactors has progressed only 20 percent, even if was scheduled to be completed in 2003. Even the delivery of heavy oil to the North promised under the agreement was stopped from December 2002. Thus, North Korea must have felt that it has lost everything, and strongly reacted by removing IAEA seals from its frozen nuclear facilities and expelling IAEA inspectors.

3) In North Korea now, rice and electricity are the most important necessities for the survival of its socialist economy. As their efforts for self-sufficiency in energy have been obstructed by the United States, the North has resorted to such extreme measures. Then, let's again examine the truth of Pyongyang's alleged weapons development.

(1) Even though North Korea may possess weapons-grade enriched plutonium, it is difficult for them to build nuclear weapons with it. The reasons are as follows: First; a nuclear bomb including plutonium and explosive will weigh about two tons, so they cannot shoot it. Second; even though Pyongyang has built nuclear bombs, they will not be able to detonate them. To detonate nuclear bombs requires very high-level technology and North lacks it. The United States has conducted more than two thousand tests to complete its detonating capability. Third; recently, all explosion tests are conducted by simulations. For it, countries need high-level scientific know-how and technology. North Korea will most desire such simulations to evade strict surveillance of the United States, but they are beyond its capabilities. If North Korea chooses testing by the traditional primitive method, it will easily be detected by the U.S and risk U.S. bombing of its nuclear facilities at Yongbyon. Will Pyongyang take such a risk?

(2) If North Korea has really intended to build nuclear bombs, it would have chosen enriched plutonium rather than reprocessing spent uranium fuel.

3) North Korea is now presumed to possess about 8 to 10 kilograms of enriched plutonium. This plutonium was sealed by IAEA, but recently Pyongyang has removed the seals. However, it is not yet known if Pyonyang can now freely use the plutonium. But even if the North possesses so much plutonium, it cannot build nuclear weapons, as has been explained so far.

4) Under such circumstances, America may say that " North Korea may have one to two nuclear weapons" or " there is 51% probability of North Korea's possessing nuclear weapons". Then, what is the reason for the U.S. to make a fuss of the current North Korean nuclear crisis ( about Pyongyang's alleged possession of enriched uranium) relying on a vague presumption? One conceivable reason is that ' the hard-liners in the Bush administration, who are determined to topple Pyongyang regime, wanted to create war danger on the Korean peninsula as they did in 1993-1994, by sending U.S. envoy James Kelly to Pyongyang in October 2002 and making rows over Pyongyang' admission of possessing a uranium-based nuclear program, and subsequently stopping delivery of heavy oil to Pyongyang. But North Korea, which well knows such schemes of Washington, has put the U.S. into dilemma by countering with drastic measures. If Bush administration mishandles Pyongyang's nuclear issue, its war-oriented unilateral foreign policy may get into trouble, so it is now professing a peaceful solution of Pyongyang's current nuclear crisis. But after its war against Iraq is over, there is a possibility of the U.S. escalating the North Korean nuclear crisis.

5. The only way to prevent a war on the peninsula that may break out by the current conflict between Washington and Pyongyang over the latter's nuclear issue will be the resumption of fuel oil shipments to Pyongyang, Washington's guarantee of Pyongyang's right to existence, and compliance with 1994 Framework Agreement (such as establishment of diplomatic relations between the two countries).

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