[DRAFT: Hiroshima Report 2013] 3-(1) The Amount of Fissile Material Usable for Weapons

(Following is a draft version, which is subject to be updated or revised. Your comments and feedbacks are welcome!)

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Nuclear security threat is defined as “a person or group of persons with motivation, intention and capability to commit criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities or associated activities or other acts determined by the State to have an adverse impact on nuclear security.”[1] The IAEA recommends to take a graded approach that takes into account: “the current evaluation of the threat, the relative ‘attractiveness’[2], the nature of the nuclear material and potential consequences associated with the unauthorized removal of nuclear material and with the sabotage against nuclear material or nuclear facilities”[3] to decide physical protection requirements. This suggests that the more suitable nuclear and other radioactive material, related nuclear facilities and activities are to achieving certain malicious intentions, the higher the nuclear security risk is, thereby requiring a high-level of protection measures corresponding to the security risk. In a similar way, the larger the consequences of a certain malicious act, the stronger the level of security measures required. 

Two kinds of malicious acts, unauthorized removal and sabotage, are present in nuclear security, and the attractiveness of potential targets differs depending on the intention of a certain act, as does the required protection level. The intentions of unauthorized removal are to construct a nuclear explosive device or to disperse radioactive material outside a facility. For the former intention, the more suitable the targeted nuclear material is for the construction of a nuclear explosive device, the higher the attractiveness of the material becomes, as well as the risk involved. Sabotage acts intend to “endanger the health and safety of personnel, the public or the environment by exposure to radiation or release of radioactive substances by intentionally attacking or destroying a nuclear facility or nuclear material in use, storage or transport.”[4] To this end, for the intentions of sabotage and unauthorized removal for radioactive material dispersal, the risk increases as the consequences can be large.

The attractiveness pertaining to unauthorized removal intended to manufacture a nuclear explosive device indicates how much nuclear material of interest is suitable for manufacturing a nuclear explosive device from the viewpoint of characteristics of the material and necessary additional processes. IAEA’s INFCIRC/225/Rev.5 categorizes nuclear material, based on its type, composition, amount, and radioactive level, into category I, II, and III (Table 3-1), from higher to lower in terms of attractiveness for unauthorized removal to make a nuclear explosive device. It recommends taking protective measures in accordance with the categorization of the material held.

 

While it is not possible to grasp the exact holdings of category I nuclear material for most countries, some estimation is possible for some countries, from the “Global Fissile Material Report 2013: Increasing Transparency of Nuclear Warhead and Fissile Material Stocks as a Step toward Disarmament” (discussed later), published by the International Panel on Fissile Materials (IPFM). In addition, countries with nuclear power plants are assumed to possess category I nuclear material and, depending on the type of research reactors, countries without nuclear power plants but only research reactors are possibly assumed to possess it as well.

Table 3-1 shows that plutonium and highly enriched uranium (HEU) (isotopic concentration of uranium-235 is 20% or more) are more attractive for manufacture of a nuclear explosive device. Among HEU, weapon grade HEU (isotopic concentration of uranium-235 is 90% or more),best suited to the manufacture of a nuclear explosive device, presents the highest attractiveness as well as nuclear security risk, and thus requires a high-level protection measures. IPFM annually publishes “Global Fissile Material Report” that summarizes the holdings of weapon usable material of some countries, this report refers to “Global Fissile Material Report 2013” (Table 3-2: Categorization of Nuclear Material) for the evaluation of fissile material holdings of each country.

Categorization of Nuclear Material

The holdings of HEU and plutonium of some countries other than the ones in Table 3-2 are estimated as follows.

Ø  Countries assumed to retain 1ton of HEU (category I is 5kg and more) : Kazakhstan （10,520kg）[5]

Ø  Countries assumed to retain 1kg and more but less than 1ton of HEU (category I is 5kg and more) : Canada (less than 1,500kg), Netherland (730-810kg), Iran (7kg), Australia (1019kg), Norway (1-9kg)[6]

Ø  Countries assumed to retain 1kg and more of separated plutonium: Netherland[7]

Even if a country does not have weapon grade HEU or plutonium but a uranium enrichment facility or a nuclear reactor with a reprocessing facility, the risk associated to the country is higher than those without these facilities. Thus, the existence of nuclear power plants, research reactors, uranium enrichment facilities, and reprocessing facilities in a country indicates the level of risk that the country faces.

Unauthorized removal that is intended to harm people by releasing radioactive substance outside a facility, nuclear or other radioactive material is a target. The IAEA recommends that a State defines the risk based on the amount, forms, composition, mobility, and accessibility of nuclear and other radioactive material and takes prospective measures against the defined risk[8]. As for sabotage, nuclear or other radioactive material and related facilities are potential targets. In this regard, the IAEA also recommends that a State “establishes its threshold(s) of unacceptable radiological consequences”[9] and vital areas where risk associated material, device, and functions are located “in order to determine appropriate levels of physical protection taking into account existing nuclear safety and radiation protection.”[10]  That is to suggest that, since the risk level is determined in accordance with not only the types, amounts/scale, and characteristics of nuclear and other radiological material and related facilities, but also policy consideration of a State, it is difficult to apply objective risk evaluations. 

Based on this understanding, Table 3-3 below describes the presence of nuclear power plants, research reactors, uranium enrichment facilities, and reprocessing facilities of surveyed countries, as a risk indicator against unauthorized removal for a nuclear explosive device. Repeating again, the possession of nuclear material usable for weapons itself presents nuclear security risks and requires robust nuclear security measures including enhanced physical protection systems at facilities. States with these kinds of nuclear material have a responsibility to ensure the reliability of control systems. In this regard, the stockpiles of fissile material that are usable for nuclear weapons and explosive devices, and the presence of related facilities previously discussed, are important indicators to evaluate the nuclear security systems of surveyed countries.

(Drafted by Kazuko Hamada, Japan Atomic Energy Agency)

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[1] International Atomic Energy Agency (IAEA), “ Objective and Essential Elements of a State’s Nuclear Security Regime,” IAEA Nuclear Security Series No. 20, 2013, p.13.

[2] This indicates the suitability to achieve malicious intents and expresses the possible perception of potential adversaries only.

[3] International Atomic Energy Agency (IAEA), “ Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5),” IAEA Nuclear Security Series No. 13, 2011, p.14.

[4] International Atomic Energy Agency (IAEA), “Recommendations: Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5),” IAEA Nuclear Security Series No. 13, 2011, p.53.

[5] James Martin Center for Nonproliferation Studies (CNS) for the Nuclear Threat Initiative (NTI), “Civil Highly Enriched Uranium: Who Has What?”.

[6] James Martin Center for Nonproliferation Studies (CNS) for the Nuclear Threat Initiative (NTI), “Civil Highly Enriched Uranium: Who Has What?”, Mexico, South Africa, and Vietnam are found that they have returned the all HEU to origin countries according to the statements in 2012 Nuclear Security Summit and other sources and thus, removed from this list. With regard to Australia, although it stated that it had returned HEU to an origin country, it is not clear whether or not some HEU remains and is not removed from the list.

[7] International Panel on Fissile Materials, “Global Fissile Material Report 2013: Increasing Transparency of Nuclear Warhead and Fissile Material Stocks as a Step toward Disarmament,” International Panel on Fissile Materials, October 2013.

[8] International Atomic Energy Agency (IAEA), “ Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5),” IAEA Nuclear Security Series No. 13, 2011.

[9] International Atomic Energy Agency (IAEA), “ Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5),” IAEA Nuclear Security Series No. 13, 2011, P.14.

[10] International Atomic Energy Agency (IAEA), “Recommendations: Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/Revision 5),” IAEA Nuclear Security Series No. 13, 2013, P.14.