Interim Storage of Spent Nuclear Fuel - Woods Hole Research Center

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storage allow it to begin to catch up with cask storage. Figure
2.3 shows the breakdown of estimated discounted costs
of pool and cask storage at several sizes. 30
For both the United States and Japan, it should be
noted that costs of the variety of benefits that may be paid
to the local community to build public acceptance and gain
government approvals are not included in these totals.
These costs will vary from zero to significant additions to
the total, depending on the circumstances of the individual
case.
The costs of interim storage of spent fuel are quite
modest when compared to either reprocessing costs (more
than $900/kgHM in current European facilities, even after
their initial capital costs have been paid, and more for
Japan’s Rokkasho-mura facility) or the costs of direct disposal.
This is to be expected, since interim storage offers
only a temporary solution, and in virtually all industries,
permanent solutions are more expensive than temporary
ones. From a strictly economic point of view, interim storage
pays for itself by allowing the reactor operator to discount
the costs of either reprocessing or direct disposal of
the spent fuel into the future. For example, at a discount
rate of 5%, a reprocessing cost of $1000/kgHM need only be
postponed for 5 years to save over $200/kgHM—somewhat
more than the lifetime dry cask storage cost estimated
in Japan. Much the same could be said, of course, with
respect to using interim storage to postpone and thus discount
the costs of direct disposal. The point is not that permanent
solutions should be postponed, but that at low
INTERIM STORAGE OF SPENT NUCLEAR FUEL
cost, interim storage provides the flexibility to implement
permanent solutions at an optimized timing and pace.
Nonproliferation and Safeguards
Aspects of Dry Storage
Spent nuclear fuel contains a small percentage of plutonium,
and therefore must be appropriately secured and safeguarded.
Indeed, more than two-thirds of all the plutonium
that now exists, over 1,100 tonnes, is in spent nuclear fuel,
in dozens of countries around the world. 31 The reactorgrade
plutonium in typical spent fuel would not be the preferred
material for making nuclear weapons, but once separated
from the spent fuel, it is weapons-usable, whether by
unsophisticated proliferators or by advanced nuclear
weapon states. 32 Fortunately, providing appropriate safeguards
and security for spent fuel in storage is a straightforward
task.
In spent fuel, plutonium is embedded in massive,
intensely radioactive fuel assemblies which would be rather
difficult to steal and recover plutonium from—and which
are easy to count and monitor. To get enough plutonium for
a bomb would require removing 1-2 roughly 670 kilogram
fuel assemblies for a pressurized water reactor (PWR), or 3-
4 roughly 250 kilogram assemblies from a boiling water
reactor (BWR)—and such removal would be quite easy to
detect. Thus, the security hazard posed by plutonium in
spent fuel is much less than the hazard posed by separated
plutonium that is directly usable in nuclear weapons. 33
30 MITI, Toward Implementation of Interim Storage for Recycled Fuel Resources, op. cit.
31 See David Albright and Mark Gorwitz, “Plutonium Watch: Tracking Civil Plutonium Inventories: End of 1999” (Washington,
DC: Institute for Science and International Security, October 2000). Albright and Gorwitz provide an estimate of
1,065 tonnes in spent fuel as of the end of 1999, but this amount increases by some 60 tonnes per year, so the total at the
end of 2000 was over 1,100 tonnes.
32 At the low end of the spectrum of sophistication (capabilities that might be available to a less developed state or, conceivably,
a particularly well-organized terrorist group), reactor-grade plutonium can be used to make an explosive with a
reliable, assured yield in the kiloton range (meaning a radius of destruction one-third that of the Hiroshima bomb) using
technologies no more sophisticated than those used in the first nuclear weapons. At the high end of the spectrum of sophistication,
advanced weapon states such as the United States and Russia could make weapons from reactor-grade plutonium
having yield, reliability, weight, and other characteristics generally comparable to those of weapons made from weapongrade
plutonium. For an official declassified statement making this point, see Nonproliferation and Arms Control Assessment
of Weapons-Usable Fissile Material Storage and Excess Plutonium Disposition Alternatives, DOE/NN-0007 (Washington, DC: U.S.
Department of Energy, January 1997), pp. 37-39.
33 For a discussion of how difficult it would be for states and non-state actors to recover plutonium from spent fuel, see
Committee on International Security and Arms Control, Panel to Review the Spent-Fuel Standard for Disposition of Excess
Weapon Plutonium, U.S. National Academy of Sciences, The Spent-Fuel Standard for Disposition of Excess Weapon Plutonium:
Applications to Current DOE Options (Washington, DC: National Academy Press, 2001), and Nonproliferation and Arms Control
Assessment of Weapons-Usable Fissile Material Storage and Excess Plutonium Disposition Alternatives, op. cit., pp. 52-60.