NRC Should Perform Non-Proliferation Assessment of Laser Enrichment Technology

[bananas]

http://www.aps.org/units/fps/newsletters/201007/slakey.cfm

NRC Should Perform Non-Proliferation Assessment of Laser Enrichment Technology

Francis Slakey & Linda Cohen

Introduction

Uranium enrichment is a step in the process to convert uranium ore into fuel for nuclear reactors. Mined uranium ore is made up of roughly 99.2% U238 and 0.72% U235. Only the latter isotope is fissionable under bombardment by slow neutrons as in a reactor, and so in order to make reactor fuel, the U235 concentration must be increased. Enrichment services that increase the concentration are measured in separative work units, or SWUs. The number of SWUs required to produce a kilogram of reactor fuel depends on the percent of U235 in the final fuel, in the natural uranium feedstock, and in the depleted uranium stream or "tail". Numerous techniques of isotope separation have been developed for enriching uranium and their efficiency can be characterized by the number of SWUs produced per megawatt hour (SWU/MWh).

A uranium enrichment technology, SILEX (Separation of Isotopes by Laser Excitation), could significantly increase efficiency beyond existing centrifuge technologies and pose significant proliferation risks <1>. In this article we argue that an examination of the economics indicates that those risks would not be outweighed by a public benefit to the consumer in the form of lower electricity bills, as some have suggested. Consequently, under the Atomic Energy Act, the Nuclear Regulatory Commission (NRC) should carry out a non-proliferation assessment of the technology to determine whether SILEX "would (not) be inimical to the common defense and security" of the United States.

As opposed to past techniques which exploited the slight difference in mass between the two isotopes, SILEX uses a laser, tuned to a particular excitation of U235, to differentiate it from the U238. More than 20 countries have dabbled in laser enrichment over the past two decades, including South Korea and Iran, without much success. SILEX was developed by the Australian company Silex Systems, and is now being commercialized exclusively by GE Hitachi. GE Hitachi has applied for a license from the NRC to operate a full-scale commercial SILEX plant in North Carolina. Currently, the U.S. is the only country in which GE-Hitachi has applied for a license. While they have not yet made a decision whether to commercialize the technology, the license is a necessary step in their development path.

There is clear private benefit to laser enrichment: If GE-Hitachi successfully commercializes SILEX, it stands to make hundreds of millions of dollars a year. A more challenging question is whether there is a net public benefit. To evaluate the public benefit, we consider three separate issues: technical, economic, and legal.

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[PamW]

1. Poor use of terminology

Mined uranium ore is made up of roughly 99.2% U238 and 0.72% U235. Only the latter isotope is fissionable under bombardment by slow neutrons as in a reactor,
=========================================

The authors of the article don't know their terminology. U-235 is not "fissionable", it is "fissile". U-238 is "fissionable".

The correct terminology is as follows. If a nuclide can undergo fission with thermal, .i.e. slow neutrons, then the nuclide is "fissile" like U-235
If a nuclide will undergo fission but only with neutrons with energy above some energy threshold, then that nuclide is "fissionable" like U-238.
The threshold energy for U-238 fission is about 1 MeV.

PamW

[PamW]

2. SILEX wasn't the original, AVLIS was

The technology employed by the SILEX process wasn't originally developed by Australia. The original name for the process was AVLIS -
Atomic Vapor Laser Isotope Separation, and was developed at the Lawrence Livermore National Laboratory in the USA back in the 1970s
and 1980s. Starting on page 10 of the following:

https://lasers.llnl.gov/science_technology/pdfs/Lasers_1972_1997.pdf

The Uranium Atomic Vapor Laser Isotope Separation (AVLIS) Program
began in 1973 to help maintain the US market share of supplying the world's
enrichment services. The program was developed to produce uranium enriched
in the uranium-235 isotope which is needed to fuel fission reactors. The goal of
this program today is to provide the world's lowest cost uranium enrichment
method for commercial power-plant fuel."

PamW