Monday, June 8, 2015

Two more Unanswered Energy Collective Comments from 2011 by Jochem Gruber.


This comment was a response to another post on Jacobson.  They are both intelligent and serious, and I think it will be still helpful to give them attention.

Jochen Gruber says:

When nuclear fuel enrichment and reprocessing is combined with commercial nuclear power generation there is a problem with possible uranium/plutonium clandestine diversion by the state or a subnational group: Henry D. Sokolski (ed.) Falling Behind: International Scrutiny of the Peaceful Atom, Strategic Studies Institute - United States Army War College, February 27, 2008

CB:Reasonable premise.

"Diversion 

Chapter 1: Henry D. Sokolski "Assessing the IAEA's Abiity to Verify the NPT"
A Report of the Nonproliferation Policy Education Center on the International Atomic Energy Agency's Nuclear Safeguards System

Currently, the IAEA is unable to provide timely warning of diversions from nuclear fuel- making plants (enrichment, reprocessing, and fuel processing plants utilizing nuclear materials directly useable to make bombs). For some of these plants, the agency loses track of many nuclear weapons-worth of material every year. Meanwhile, the IAEA is unable to prevent the overnight conversion of centrifuge enrichment and plutonium reprocessing plants into nuclear bomb-material factories. As the number of these facilities increases, the ability of the agency to fulfill its material accountancy mission dangerously erodes. The IAEA has yet to concede these points by admitting that although it can monitor these dangerous nuclear activities, it cannot actually do so in a manner that can assure timely detection of a possible military diversion - the key to an inspection procedure being a safeguard against military diversions.
Chapter 5: Edwin S. Lyman "Can Nuclear Fuel Production in Iran and Elsewhere be Safeguarded Against Diversion?"

CB: Here we have a spacific case, that of Iran, in which inadiquate safeguards are in place.  Without knowing the exact system of safeguard that might be in place, how is it possible to determine
whether or not those systems would be sucessful.?  Perhaps we have a satisfactory account of a plausible  safeguard system somewhere else, but as it stands, we have inadiquate information to determine the validity of the argument.

"[Significant Quantity]
[Dr. Marvin] Miller [Massachusetts Institute of Technology, in "Are IAEA Safeguards on Bulk-Handling Facilities Effective?", Nuclear Control
Institute, Washington, DC, USA, 1990]observed that for large bulk handling facilities, such as the 800 metric ton heavy metal (MTHM)/year Rokkasho Reprocessing Plant (RRP) now undergoing startup testing in Japan, it was not possible with the technologies and practices available at the time to detect the diversion of 8 kilograms of plutonium (1 significant quantity, SQ) - about 0.1 percent of the annual plutonium throughput - with a high degree of confidence. This is because the errors in material accountancy measurements at reprocessing plants were typically on the order of 1 percent -that is, a factor of 10 greater than an SQ. If after taking a physical inventory, the value of plutonium measured was less than expected (on the basis of operator records) by an amount on the order of 1 SQ, it would be difficult to state with high confidence that this shortfall, known as "material unaccounted for" or MUF, was due to an actual diversion and not merely measurement error."

CBHere we have a statement that presupposes a facility designed to extract Reactor Grade Plutonium from Spent Nuclear Fuel.  I will shortly point out the problems associated with using Reactor Grade Plutonium in Nuclear weapons.

[Accountancy Verification Goal - Expected Accountancy Capability (E)]

"In the past, the IAEA acknowledged that the 1 SQ detection goal could not be met in practice, and instead adopted a relaxed standard known as the "accountancy verification goal" (AVG), which was "based on a realistic assessment of what then-current measurement techniques applied to a given facility could actually detect." The AVG was based on a quantity defined as the "expected accountancy capability," E, which is defined as the "minimum loss of nuclear material which can be expected to be detected by material accountancy," and is given by the formula

E = 3.29 sigma A,

in which sigma is the relative uncertainty in measurements of the plant's inputs and outputs, and A is the facility's plutonium throughput in between periodic physical inventories.

This formula is derived from a requirement that the alarm threshold for diversion be set at a confidence level of 95 percent and a false alarm rate of 5 percent. Miller estimated that for the RRP, based on an input uncertainty of ±1 percent (which was the IAEA's value at the time for the international standard for the expected measurement uncertainty at reprocessing plants), the value of E would be 246 kilograms of plutonium, or more than 30 SQs, if physical inventories were carried out on an annual basis, as was (and is) standard practice. This means that a diversion of plutonium would have to exceed this value before one could conclude with 95 percent certainty that a diversion had occurred, and that the measured shortfall was not due to measurement error."

CB:  Here we have a statement of the the potential for diversion of Reactor Grade Plutonium.  My plan for my rresponse to Jochen Gruber 's comment is t0o lay out his view on RGP before I respond to it.

In a second Energy Collective comment to the same paper Gurber offered these responses:


"Thank you for this very resourceful paper! Although I tend to think along the lines of Jaconson, your arguments appear very convincing to me (my training is in nuclear physicis).

Some technical points:

(1) CANDU reactors have a modular structure such that you can exchange fuel rods without shutting down the entire reactor. This makes it much more easy to breed weapon's grade plutonium with CANDU reactors than with Light Water Reactors, because to breed weapons grade plutonium you need to keep the irradiation time of the fuel small. This means you need to exchange the fuel elements more frequently than when you merely want to generate electricity."

CB: There are problems which would make the CANDU path to nuclear weapons inpractical for every one but Canada and India.  First The fuel for CANDU reactors  The fuel comes in the form of ceramic and Zirconium fuel bundles.  If a fuel bundlr is puled out of a CANDU reactor, and replaced.  The process of extracting Reactor Grade Plutonium requires destroying the irradiated fuel bundle in order to recover the plutonium.

Several bundles would have to be replaced in order to acquire enough WGP to creat a nuclear weapon.  Since each fuel bundle has to be purchased from the reactor manufacturer, the would be proliferator would have to account for the missing fuel bundles.  India already has nuclear weapons, while who is worried about Canada becoming a hostile nuclear power?  Thus the CANDU argument may be the product of a lively imagination, it does not identify a serious proliferation risk.

(2) "Reactor Plutonium has been used for low yield (below 20 kt) nuclear explosions"

CB: This argument is dependent on classifying plutonium with 80% to 90% Pu-239 content.  The Pu-239 content found in spent nuclera fuel is closer to 50% with Pu-240.  I will shortly discuss the problems of militarizing RGP.  The claim that RGP devices has been tested rests on an equivocation.  At the time of the tests, the term RGP encompased Plutonium of from 80% to 90% Pu-239 composition. Although both tests produced significan explosions, neither appears to have been an unqualified success.

(3) Low Enriched Uranium as fed into Light Water Reactors can be used to shorten the path to weapons grade uranium (Victor Gilinsky, Marvin Miller, Harmon Hubbard, A Fresh Examination of the Proliferation Dangers of Light Water Reactors, October 22, 2004, The Nonproliferation Policy Education Center, Washington, DC, USA)

CB: This is of course understood.  If a nation possess Uranium isotope seperation technology, it can be used to enrich uranium to weapons grade.  The case of Iran, Pakistan and North Korea demonstrates that uranium seperation technology can be obtained by criminal means. This is true whether or not civilian power reactors are built in the United States, or Western Europe.

(4) Iran claims to use its enrichment plant for a civilian nuclear (energy) program. If there weren't nuclear power plants, enrichment would clearly be identifiable as having a military application.

Of course, but this argument does not show that the building of reactors in the United States will lead to the aquisition of nuclear weapons by Iran

(4) Off Topic:
For countries with covert or declared enrichment plants, timely detection of weapons grade uranium made from low enriched uranium as used in Light Water Reactors is not possible (page 30, Fig. 4 of Falling Behind: International Scrutiny of the Peaceful Atom, Henry Sokolski (ed.), The Nonproliferation Policy Education Center, 2008)

CB: This is true, but countries that produce illicit nuclear weapons, may have a heavy price extracted from them, witness the sanctions imposed on Iran and North Korea.

I will now finally respond to the Reactor Grade Plutonium argument.  Nuclear weapons experts such as Alexander Di Volpi have oiinted out major flaws in argument that nuclear weapons can be manufactured using RGP:

Radioactive Pu-238 produces significant heat as it decays.  The heat from U-238 is  damaging to the chemical explosives used to trigger plutonium weapons.  Eventually the usefulness of the RGP weapon is compromised.  Secondly, U-240 which may be as much as 25 of the plutonium found in RGP, fissions spontaniously.  This does mischafe in two ways.  First it causes neutron radiation, a highly undesirable state of affairs, if the weapon comes into close contact with people.  In addition the neutron radiation can over time damage the electronics used to trigger the initial chemical explosion.  Finally, the neutron release from Pu-240 will lead to a premature triggering of a GP device.   his premature triggering causes an explosive punch that maybe no more than 1% of a standard Plutonium weapon.  But why use a nuclear weapon, with all its complications, if its punch is not that much greater than a truck full of high explosives?

1 comment:

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