Appendix A - Covert Reprocessing of Reactor-Grade Plutonium and Possible Use in Nuclear Weapons

Russian authorities have claimed that Iran does not currently have the means of reprocessing nuclear fuel from the Bushehr nuclear reactor.(1) And even if they did have the means of reprocessing, the separated plutonium is not suitable for use in a nuclear weapons.(2)

This section will attempt to address those claims and show that their are definite proliferation concerns. All information presented is from open literature sources.

In 1977 Oak Ridge National Laboratory published a report outlining a conceptual design for a "simple and quick" plant for reprocessing spent nuclear fuel.(3) The GAO was asked to evaluate the Oak Ridge report's credibility and policy implications.

GAO reached three conclusions about that report:

1. The Oak Ridge estimate of 4 to 6 months for constructing a small reprocessing facility, although not highly probable, should be considered credible in some circumstances.

2. The possibility of quick construction of secret reprocessing plants is not a significant factor in deciding whether to allow reprocessing of spent fuel.

3. The memorandum serves to reemphasize the importance of US initiatives to improve controls on spent nuclear fuel.

Relevant comments from the GAO analysis are as follows:

Without concern for the problems of safety handling radioactive materials a small reprocessing plant could be built in 4 to 6 months. The first 10 kilograms of plutonium could be recovered about a week after initial operation, and about 5 kilograms of plutonium per day thereafter. When other requirements such as the time to design the plant, recruit and train designers and operators, find a suitable site and stockpile critical equipment are considered the time to plant completion increases anywhere from 19 to 30 months. Of significant interest is that no reviewer of the Oak Ridge report said "that the construction and operation of a small reprocessing plant by a nonnuclear-weapons nation was not technically feasible". In fact most agreed that a small plant could be built without difficulty but would require trained operators.

Iran possesses the knowledge and capability to build a small reprocessing facility on its own. But it may be able to draw on the expertise of other countries that have performed small scale reprocessing such as South Africa, Taiwan or Yugoslavia.

In addition evidence is now appearing that Algeria may be involved in a covert reprocessing program.(4)

The reprocessing technology available from these countries will be discussed in the next section.

Yugoslavia:

Yugoslavia has investigated the reprocessing and purification of plutonium on a large-scale laboratory effort at all three major nuclear research institutes (Rudjer Boskovic Institute, Josef Stefan, and the Boris Kidric Institute).(5) The first laboratory scale investigations began at the Rudjer Boskovic Institute in the 1950's.(6) The Boris Kidrich Institute began the investigation of the PUREX process for nuclear fuel reprocessing in the mid 1950's.(7) These early experiments were performed in collaboration with Norway.(8) The extraction work itself was performed at the Joint Institute for Nuclear Research located at Lillestrom, Norway.

A description of for a large scale facility was presented at the 1964 International Conference on the Peaceful uses of Nuclear Energy.(9) This facility was designed to reprocess fuel from the Yugoslavian RA reactor. That fuel consisted of 2% enriched uranium, clad in aluminum. The plant was designed to reprocess natural or low enriched metallic uranium canned in aluminum or magnesium. However the plant could also treat uranium dioxide fuel canned in Zircaloy. the sent fuel was estimated to contain 0.8 grams of plutonium and 3 grams of fission products per 1 kilogram of uranium. Extraction was to be done by the batch process and would be able to reprocess about 30 kilograms per day. Cooling time for the irradiated fuel before reprocessing was estimated to be 120 days. The process used for purification is a modified PUREX type process and was said to be able to produce 20 grams of plutonium per day. Details were also presented on the use of trilaurylamine for the extraction and purification of plutonium.

A description of the laboratory scale apparatus used in most of the reprocessing studies was given in two 1967 papers.(10) The apparatus was charged with a solution containing irradiated uranium (100-150 grams) having a maximum fission product activity of 100 Ci. The continuous purification process using a PUREX type process was said to give 6 grams of uranium per hour.(11) No details were given on plutonium production rates. The apparatus itself was housed in two hot cells that were shielded with lead.

Studies were also performed on modifications to the PUREX process in an attempt to improve yields and increase efficiency.(12) it is of interest to note that one of the main researchers in this effort was from the Nuclear Research Institute of the Czechoslovak Academy of Science.

Details have also been openly presented on the separation of neptunium, plutonium, americium and thorium by ion exchange methods.(13) The ion exchange resin used is the commercially available Dowex 1X4.

Engineering studies on the large scale development of the extraction processes were detailed in a series of papers.(14) These papers provide information on the use of countercurrent extractors and the difficulties associated with their use. The same team that worked out the procedures for small scale plutonium extraction also supported this large scale development. Japanese researchers are known to have assisted Yugoslavia in the design of countercurrent extractors.(15)

Research at the Boris Kidrich Institute continues to this day. Recent articles have highlighted research on mathematical modeling of PUREX type systems.(16)

The Josef Stefan Institute (Serbia) under IAEA sponsorship has held annual training courses in Tehran for junior Iranian engineers.(17) The IAEA has also given classes in nuclear material handling and nuclear power plant construction.(18) These classes represent an excellent opportunity for recruitment of skilled workers by Iran.

With the disintegration of Yugoslavia many of these scientists are looking for work. The possibility of recruitment by Iran is of particular concern. The effect of the covert program by the US to use Iran to supply Bosnia with arms needs to be analyzed.(19) Whether these ties will be exploited by Iran to gain access to sensitive technology remains to be seen.(20)

South Africa:

South Africa's Atomic Energy Corporation is very dire straits at the present time. AEC executive G.M. Mojalefa Myrphy has said " We have already lost hundreds of experienced scientists and engineers to overseas research institutions".(21) There exists a real danger that South African engineers and technicians are at work in Iran.

South Africa is known to have run a small scale project looking into the possibility of separating plutonium from leftover uranium in spent reactor fuel.(22) Small scale extractive work was done using the commercially available product, Lewatit OC 1023. This method of plutonium separation was stated "to be ideally suited to small-scale application in the nuclear industry. Recovery and separation of the actinides from waste solution may be easily effected in glove boxes and/or hot cells. Only small amounts of specialized extractants are needed and multistage operation is possible due to the use of columns rather than the more cumbersome liquid-liquid extraction".

The possibility of transfer of this technology to a covert reprocessing program can not be overlooked.

Taiwan:

Taiwan also poses a proliferation concern due to technology transfer considerations. Scientists from the INER and the National Tsing-Hua University are known to have been involved with Saudi Arabian nuclear efforts.(23) Saudi Arabia recruited leading Islamic scientists such as Sumer Sahin of Turkey to perform nuclear research. Some of this research was known to have direct military applications.(24) The recruited scientists and Saudi nuclear scientists are known to have performed research in Taiwan.

Of further concern is work done on reprocessing done during the same period of time.(25) While this technology may not have been transferred to other countries, publishing does allow foreign intelligence organizations to identify possible contacts.

However of more relevance to a reprocessing program is the published information on a low-cost hot facility.(26) This type of facility would be ideal for small-scale extraction work.

Assessment:

Using these three countries as examples one sees that a small covert reprocessing facility is not beyond Iran's technical reach. In fact with either Chinese or Russian technical assistance such a facility becomes very feasible. Only a few experienced individuals would be needed to run such a facility.

Suitability of Reactor-Grade Plutonium for Use in Nuclear Weapons:

Once a country has isolated significant amounts of plutonium (kilograms) its suitability for use in a nuclear weapon must be determined. Much controversy exists over whether reactor-grade plutonium can be used to make reliable and high-yield nuclear weapons. It has been established that fuel-grade plutonium can be used in nuclear weapons.

The controversy over whether reactor-grade plutonium is suitable for use in a nuclear weapon goes back many years.(27) Both sides have provided evidence to support their claims.

In 1962 the US successfully tested a nuclear weapon using such plutonium.(28) The release of this information has renewed the controversy over whether reactor-grade plutonium can be used in a nuclear weapon. A recent analysis casts doubts on whether reactor-grade plutonium was really used in the test. DeVolpi presents calculations and information claiming that the plutonium used was fuel-grade and not reactor-grade.(29) The difference between the two grades is the amount of the different plutonium isotopes in the sample, particularly the amount of Pu-239 in the grade.

DeVolpi's analysis is backed up by claims from both French government and industry officials.(30) Cogema officials say "that the isotopic content of that Pu, with low burnup from a British magnox reactor, was close to that of military-grade Pu". "Such an explosive had never been made with Pu from spent LWR fuel with higher discharge burnups, and, where it attempted, it would not work" said Jean-Pierre Rougeau, Cogema's senior manager of strategic planning and international relations. The French government had this to say "The US had given few data about the isotopic composition of the Pu that went into the 1962 bomb, and that it probably came from a slightly irradiated fuel with isotopic characteristics close to military-grade Pu. To be sure it is correct that despite its lower content in the isotope 239, civilian-grade plutonium can theoretically be used to fabricate an explosive device. But the fabrication of such a device would be much more complex than one using higher-grade Pu, for a very uncertain result in terms of safety and efficiency".

Carson Marks (former head of the Theoretical Division of Los Alamos National Laboratory) presented a series of articles outlining the feasibility of using reactor-grade plutonium in a nuclear weapon.(31) His conclusions were that it is possible to produce a weapon with at least at a 'fizzle' yield. Richard Garwin has also reached the same conclusions.(32)

To compound the issue Indian sources claim that the sub-kiloton tests performed on May 11, 1998 used reactor-grade plutonium.(33) India Today claimed that reliable sources had informed the magazine that the low level explosion did use reactor-grade material. No further details where provided of this test.

One the main questions surrounding reactor-grade plutonium is whether a suitable assembly could be obtained before preinitiation occurred. Iran is known to have recruited a scientist (Khaled Nickov) who claimed to be connected with the shock compression group under R.F. Trunin. if this is true then Iranian could design a weapon with a suitable assembly time. Trunin's group has designed an assembly that can compress heavy metals up to 2.5 TPa.(34) Without such experts it is believed Iran would have a difficult time producing reliable weapons.

Lastly without a source of weapons-grade plutonium could reactor-grade material be upgraded? Such a question has been addressed before in Congressional hearings and the result is yes.(35) However this technology is beyond the capability of all but the most advanced countries.(36)

Iran faces numerous hurdles in the fabrication and militarization of nuclear weapons. However the availability of foreign assistance will shorten the time and complexity of the task.