Gregory S. Jones, “Constraints on Possible High Yield North Korean Nuclear Weapons: Weight and Nuclear Material Requirements,” August 24, 2021.  North Korea’s nuclear weapons appear to rely almost exclusively on HEU.  As a result, any high yield weapons will be relatively heavy, limiting the range of North Korean ballistic missiles.  These weapons will also require large amounts of HEU, reducing the size of North Korea’s nuclear stockpile.  To read a pdf of the full paper click here


Gregory S. Jones, “Pakistan’s Nuclear Material Production for Nuclear Weapons,” February 16, 2021.  Estimates of Pakistan’s nuclear material production need to account for the production of tritium for boosted nuclear weapons.  Currently Pakistan could have enough nuclear material for about 250 nuclear weapons of which 100 could be boosted.  Pakistan appears to have the capacity to supply sufficient natural uranium to support its nuclear material production.  To read a pdf of the full paper click here


Gregory S. Jones, “The U.S. Program to Produce Tritium Using Commercial Power Reactors: 2019 Update.”  January 30, 2020.  The U.S. program to produce tritium using the commercial nuclear power reactors at Watts Bar appears to be turning the corner.  Watts Bar 1 will likely demonstrate the necessary per reactor tritium production rate when its current batch of TPBARs are discharged in the spring of 2020.  However, until there is sufficient tritium production at Watts Bar 2, which will likely not occur until the fall of 2023 at the earliest, the U.S. tritium stockpile will continue to decline.  To read a pdf of the full paper click here


Gregory S, Jones, “Do India and Pakistan Possess Boosted Nuclear Weapons?  Tritium Supply Considerations,” July 31, 2019.  An examination of the possible sources of Indian and Pakistani tritium can provide insight into whether these countries possess boosted nuclear weapons.  It does not appear that India has extracted any significant quantities of tritium from its heavy water moderated power reactors.  As a result, India probably has few if any boosted nuclear weapons in its arsenal.  On the other hand, Pakistan could be producing large amounts of tritium if it is irradiating lithium in several of its plutonium production reactors at Khushab.  Pakistan is therefore more likely than India to possess a significant number of boosted nuclear weapons.  To read a pdf of the full paper click here


Gregory S. Jones, “Estimating Israel’s Stocks of Plutonium, Tritium and HEU,” September 18, 2018.  Estimates of Israel’s nuclear material stocks must take into account the production of tritium at the Dimona reactor in addition to plutonium.  Producing tritium requires using enriched uranium fuel, which in turn implies that Israel has an indigenous uranium enrichment capacity.  Israel’s nuclear arsenal size is likely in the range of 80 to 145 weapons.  Since Israel has only conducted one nuclear test, it probably only has boosted nuclear weapons but not two-stage thermonuclear ones.  To read a pdf of the full paper click here


Gregory S. Jones, “The U.S. Program to Produce Tritium Using Commercial Light Water Power Reactors: An Update,” February 7, 2018.  The U.S. is moving ahead with efforts to increase tritium production.  However, unspecified problems are limiting tritium production at Watts Bar 1, which may be causing shortages in the U.S. nuclear weapon program.  As a result, plans to start tritium production at Watts Bar 2 are being ramped up.  The recently released Nuclear Posture Review has emphasized the critical importance of increasing tritium production.  To read a pdf of the full paper click here

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Gregory S. Jones, “North Korea’s Sixth Nuclear Test: Was It a Hydrogen Bomb?” September 18, 2017.  North Korea’s sixth nuclear test had a yield significantly higher than its previous nuclear tests.  However, the test was probably not that of a full yield hydrogen bomb.  More likely possibilities are either a pure fission device or a device related to the development of a hydrogen bomb.  Whatever type of device was tested is likely too large and heavy to be carried on North Korea’s ICBM.  A more reasonable possibility for an ICBM warhead is a small, lightweight pure fission weapon with a yield of 10 to 30 kilotons.  To read a pdf of the full paper click here

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Gregory S. Jones, “The Role of Boosting in Nuclear Weapons Programs,” July 25, 2017.  Boosting is not an intermediate technology on the road to two-stage thermonuclear weapons.  Four of the five countries that possess two-stage thermonuclear weapons have developed and/or deployed these weapons before boosted weapons.  In countries that have not developed two-stage thermonuclear weapons, stand-alone boosted weapons may be used to provide small, light weapons that use reduced amounts of nuclear material.  To read a pdf of the full paper click here

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Gregory S. Jones, “History of U.S. Production of Tritium 1948-1988,” June 12, 2017.  This history demonstrates that though the U.S. tested its first boosted nuclear weapon in 1951, it did not quickly decide to deploy such weapons which the U.S. did not produce until 1957.  The history also shows that at the peak of the U.S. nuclear stockpile in the 1960s, the U.S. tritium stockpile was roughly 100 kilograms.  To produce tritium the U.S. initially used natural lithium but later used lithium enriched up to 50%. To read a pdf of the full paper click here

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Gregory S. Jones “U.S. Increased Tritium Production Driven by Plan to Increase the Quantity of Tritium per Nuclear Weapon,” June 2, 2016.  Tritium is a vital component of every U.S. nuclear weapon.  The U.S. plans to significantly increase the amount of tritium per weapon.  This change is intended to reduce the frequency with which the tritium reservoirs in the weapons are replaced and to help ensure weapon reliability in an era where there is no nuclear testing.  I have estimated that the average amount of tritium per weapon will increase by about 50% from about 3.2 grams to roughly 4.5 to 5.0 grams.  Tritium production will need to rise significantly and will require the use of a second commercial nuclear power reactor.  To read a pdf of the full paper click here

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Gregory S. Jones, “Heavy Water Nuclear Power Reactors: A Source of Tritium for Potential South Korean Boosted Fission Weapons,” February 29, 2016.  South Korea has accumulated an unsafeguarded stockpile of over four kilograms of tritium extracted from its heavy water moderated nuclear power plants.  If South Korea should give in to calls for it to develop nuclear weapons, the tritium could be used to boost any nuclear weapon that South Korea produces. To read a pdf of the full paper click here 

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Gregory S. Jones, "The Implications of North Korea Testing a Boosted Nuclear Weapon,” January 11, 2016.  North Korea may have tested a boosted fission weapon on January 6, 2016.  If so North Korea can now manufacture small light-weight nuclear weapons with reduced fissile material content, without sacrificing yield.  These weapons could allow North Korea to easily equip its ballistic missiles with nuclear warheads and to rapidly expand its nuclear arsenal.  The continued diffusion of boosting technology could make such weapons the norm for all countries seeking to acquire nuclear weapons. To read a pdf of the full paper click here

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Gregory S. Jones, “Fissile Material Conversion Times, Wastage and Significant Quantities: Lessons from the Manhattan Project,” December 16, 2015.  The experience of the Manhattan Project demonstrates that the time required to produce the fissile material metal core for a nuclear weapon starting from uranium hexafluoride or plutonium nitrate is only about one week.  The wastage in this process is no more than 3% to 6%.  Even for the simple Nagasaki weapon design, the IAEA estimates of “significant quantities” are too high.  To read a pdf of the full paper click here