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=== Reaction to the announcement ===
=== Reaction to the announcement ===
Fleischmann and Pons' anouncement drew wide media attention. Scores of laboratories in the United States and abroad attempted to repeat the experiments.<ref name="Browne_1989"/> A few reported success, many others failure.<ref name="Browne_1989"/> Even those reporting success had difficulty reproducing Fleischmann and Pons' results.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=1}}</ref> One of the more prominent reports of success came from a group at the [[Georgia Institute of Technology]], which observed neutron production.<ref name="Broad_1989">{{harvnb|Broad|1989}}</ref>. The Georgia Institute group later retracted their announcement.<ref name="Wilford_1989">{{harvnb|Wilford|1989}}</ref> For weeks, competing claims, counterclaims and suggested explanations kept what was referred to as "cold fusion" or "fusion confusion" in the news.<ref>{{harvnb|Bowen|1989}}</ref>
Fleischmann and Pons' anouncement drew wide media attention. Scores of laboratories in the United States and abroad attempted to repeat the experiments.<ref name="Browne_1989"/> A few reported success, many others failure.<ref name="Browne_1989"/> Even those reporting success had difficulty reproducing Fleischmann and Pons' results.<ref name="Kee_1999_1">{{harvnb|Kee|1999|p=1}}</ref> One of the more prominent reports of success came from a group at the [[Georgia Institute of Technology]], which observed neutron production.<ref name="Broad_1989">{{harvnb|Broad|1989}}</ref>. The Georgia Institute group later retracted their announcement.<ref name="Wilford_1989">{{harvnb|Wilford|1989}}</ref> For weeks, competing claims, counterclaims and suggested explanations kept what was referred to as "cold fusion" or "fusion confusion" in the news.<ref>{{harvnb|Bowen|1989}}</ref>


In May 1989, the [[American Physical Society]] held a session on cold fusion, at which were heard many reports of experiments that failed to produce evidence of cold fusion. At the end of the session, eight of the nine leading speakers stated they considered the initial Fleischmann and Pons' claim dead.<ref name="Browne_1989">{{harvnb|Browne|1989}}</ref>
In May 1989, the [[American Physical Society]] held a session on cold fusion, at which were heard many reports of experiments that failed to produce evidence of cold fusion. At the end of the session, eight of the nine leading speakers stated they considered the initial Fleischmann and Pons' claim dead.<ref name="Browne_1989">{{harvnb|Browne|1989}}</ref>
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=== 1989 DOE panel ===
=== 1989 DOE panel ===
The [[United States Department of Energy]] organized a special panel to review cold fusion theory and research.<ref name="DOE_1989_39">{{harvnb|US DOE|1989|Ref=DOE1989|p=39}}</ref> In November of 1989, the panel issued its report, concluding that results as of that date did not present convincing evidence that useful sources of energy would result from phenomena attributed to cold fusion.<ref name="DOE_1989_36">{{harvnb|US DOE|1989|Ref=DOE1989|p=36}}</ref> The panel noted the inconsistency of reports of excess heat and the greater inconsistency of reports of nuclear reaction byproducts. Nuclear fusion of the type postulated would be inconsistent with current understanding and would require the invention of an entirely new nuclear process. The panel was against special funding for cold fusion research, but supported modest funding of focused experiments within the general funding system."<ref name="DOE_1989_37">{{harvnb|US DOE|1989|Ref=DOE1989|p=37}}</ref>
The [[United States Department of Energy]] organized a special panel to review cold fusion theory and research.<ref name="DOE_1989_39">{{harvnb|US DOE|1989|Ref=DOE1989|p=39}}</ref> In November of 1989, the panel issued its report, concluding that results as of that date did not present convincing evidence that useful sources of energy would result from phenomena attributed to cold fusion.<ref name="DOE_1989_36">{{harvnb|US DOE|1989|Ref=DOE1989|p=36}}</ref> The panel noted the inconsistency of reports of excess heat and the greater inconsistency of reports of nuclear reaction byproducts. Nuclear fusion of the type postulated would be inconsistent with current understanding and would require the invention of an entirely new nuclear process. The panel was against special funding for cold fusion research, but supported modest funding of focused experiments within the general funding system."<ref name="DOE_1989_37">{{harvnb|US DOE|1989|Ref=DOE1989|p=37}}</ref>
==Junk science and pathological science controversies==
In the ensuing years, several books came out critical of cold fusion research methods and the conduct of cold fusion researchers.<ref>{{harvnb|Taubes|1993}}, {{harvnb|Close|1992}}, {{harvnb|Huizenga|1993}, {{harvnb|Park|2000}}}</ref>


=== Further developments (1989-2004) ===
Cold fusion claims are extraordinary.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=3}}</ref>. Unless the [[Cold fusion#Theoretical issues|theoretical issues]] can be addressed, it will take extraordinarily conclusive data to convince most scientists that cold fusion has been discovered. <ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=3}}</ref> The fiasco following the Pons Fleischmann announcement has combined with the theoretical issues to make most scientists dismissive of new experimental claims.<ref>{{harvnb|Schaffer and Morrison|1999|Ref=Saeta1999|p=3}} ("You mean it's not dead?" – recounting a typical reaction to hearing a cold fusion conference was held recently) </ref>
After the 1989 review by the DOE, cold fusion was generally seen as an example of pathological science. Science writers [[Robert L. Park]] and [[Gary Taubes]] have published books criticizing cold fusion experiments and researchers.<ref name="Taubes_1993">{{harvnb|Taubes|1993}}</ref><ref name="Park_2000">{{harvnb|Park|2000}}</ref>


In June 1990, Gary Taubes wrote an editorial in [[Science (magazine)|Science]] suggesting that Texas A&M cells might have been spiked with tritiated water.<ref>{{harvnb|Taubes|1990}}</ref> A 3-professor panel of Texas A&M later found that none of the experiments were fraudulently conducted, saying that spiking was unlikely because scientists got different results when they tested the spiking theory by intentionally putting tritium in water.<ref>{{harvnb|New York Times|1990}}</ref><ref>{{harvnb|Storms|1990}}</ref> John Bockris later published his side of the controversy and a defense of academic freedom in "Accountability in Research".<ref>{{harvnb|Bockris|2000}}</ref>
There is, however, group of scientists who continue to do cold fusion research.<ref>{{harvnb|Storms|2007}}</ref> These scientists seek explanation for failed reproductions and give greater weight to the claimed successes.<ref>{{harvnb|Storms|2007}}</ref> This divergence has become part of a debate as to whether there is a [[pathological science]] condition in which a hypothesis once stated can never be firmly rejected.<ref>{{harvnb|Voss|1999}}, {{harvnb|Platt|1998}}</ref>
==Theoretical issues==
Postulating cold fusion to explain experimental results raises at least three separate theoretical problems.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=1}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}} ("It has been said . . . three 'miracles' are necessary")</ref>
===The probability of reaction===
Because nuclei are all positively charged, they strongly repel one another.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=1}}</ref> Normally, very high energies are required to overcome this repulsion.<ref>{{harvnb|Schaffer and Morrison|1999|Ref=Saeta1999|p=1,3}}</ref> Extrapolating from known rates at high energies, the rate at room temperature would be 50 orders of magnitude lower than needed to account for the rported excess heat.<ref>{{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}}, {{harvnb|Goodstein|1994}}</ref>
===The branching ratio===
Fusion is a two-step process.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=1}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}}, {{harvnb|Goodstein|1994}}</ref> In the case of deuterium fusion, the first step is combination to form a high energy intermediary:
:D + D -> <sup>4</sup>He + 24 MeV
In high energy experiments, this intermediary has been observed to quickly decay through three pathways.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=2}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}}</ref>
:n + <sup>3</sup>He + 3.3 MeV (50%)
:p + <sup>3</sup>H + 4.0 MeV (50%)
:<sup>4</sup>He + γ + 24 MeV (10<sup>-6</sup>)
The first two reactions are equally probable, and if one watt of nuclear power were produced, the neutron and tritium production would be easy to measure.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=2}}</ref> Based on attempts to detect neutrons and tritium (<sup>3</sup>H), the actual rates of the first two pathways are at least five orders of magnitude too low, meaning the branching probabilities given above would have to be completely reversed to strongly favor the third pathway.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=2}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}} , {{harvnb|Goodstein|1994}} (explaining Pons and Fleischmann would both be dead if they had produced neutrons in proportion to their measurements of excess heat)</ref>
===γ-ray conversion to heat===
The γ-rays of the <sup>4</sup>He pathway, are not observed. This type of radiation is not stopped by electrode or electrolyte materials, making it necessary to postulate that the 24 MeV excess energy is transferred into the host metal lattice prior to the intermediary's decay.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=2}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}}</ref> The speed of the decay process together with the inter-atomic spacing makes such a transfer inexplicable in terms of conventional understandings of momentum and energy transfer.<ref>{{harvnb|Goodstein|1994}}, {{harvnb|Scaramuzzi|2000|Ref=Scaramuzzi_2000|p=4}} </ref>


In 1991, [[Eugene Mallove]] stated that the negative report issued by the [[MIT Plasma Science and Fusion Center|MIT Plasma Fusion Center]] in 1989, which was highly influential in the controversy, was inaccurate. After lodging an official complaint, Mallove resigned from his post as chief science writer at the MIT news office on [[June 7]], [[1991]].<ref>{{harvnb|Brooks|2008|p=65}}</ref>

In 1991, researcher [[Andrew Riley]] was killed when a cold fusion cell exploded, possibly due to accumulation of deuterium gas and the failure of a safety valve.<ref name="Charles_1992">{{harvnb|Charles|1992}}</ref>

In September 1990, [[Fritz Will]], Director of the [[National Cold Fusion Institute]], compiled a list 92 groups of researchers from 10 different countries that had reported excess heat, tritium, helium4, neutrons or other nuclear effects.<ref>{{harvnb|Mallove|1991|p=246-248}}</ref> Proponents estimate that 3,000 cold fusion papers have been published, <ref>{{harvnb|Anderson|2007}}</ref> including over 1,000 journal papers and books, where the latter number includes both pro and con articles.{{Ref label|Britz|α|2}}


=== Further developments (1989-2004) ===
Fleischmann and Pons relocated their laboratory to France under a grant from the [[Toyota Motor Corporation]]. The laboratory, IMRA, was closed in 1998 after spending £12 million on cold fusion work.<ref>{{harvnb|Voss|1999}}</ref>
Fleischmann and Pons relocated their laboratory to France under a grant from the [[Toyota Motor Corporation]]. The laboratory, IMRA, was closed in 1998 after spending £12 million on cold fusion work.<ref>{{harvnb|Voss|1999}}</ref>
[[Image:Cold-fusion-calorimeter-nhe-diagram.png|thumb|A cold fusion [[calorimeter]] of the open type, used at the New Hydrogen Energy Institute in Japan. ''Source: SPAWAR/US Navy TR1862'']]
[[Image:Cold-fusion-calorimeter-nhe-diagram.png|thumb|A cold fusion [[calorimeter]] of the open type, used at the New Hydrogen Energy Institute in Japan. ''Source: SPAWAR/US Navy TR1862'']]
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To provide a forum for researchers to share their results, the first International Conference on Cold Fusion was held in 1990. The conference, recently renamed the International Conference on Condensed Matter Nuclear Science, is held every 12 to 18&nbsp;months in various countries around the world. The periodicals ''Fusion Facts'', ''Cold Fusion Magazine'', ''Infinite Energy Magazine'', and ''New Energy Times'' were established in the 1990s to cover developments in cold fusion and related new energy sciences. In 2004 [http://www.iscmns.org/ The International Society for Condensed Matter Nuclear Science] was formed "To promote the understanding, development and application of Condensed Matter Nuclear Science for the benefit of the public."
To provide a forum for researchers to share their results, the first International Conference on Cold Fusion was held in 1990. The conference, recently renamed the International Conference on Condensed Matter Nuclear Science, is held every 12 to 18&nbsp;months in various countries around the world. The periodicals ''Fusion Facts'', ''Cold Fusion Magazine'', ''Infinite Energy Magazine'', and ''New Energy Times'' were established in the 1990s to cover developments in cold fusion and related new energy sciences. In 2004 [http://www.iscmns.org/ The International Society for Condensed Matter Nuclear Science] was formed "To promote the understanding, development and application of Condensed Matter Nuclear Science for the benefit of the public."

In September 1990, [[Fritz Will]], Director of the [[National Cold Fusion Institute]], compiled a list 92 groups of researchers from 10 different countries that had reported excess heat, tritium, helium4, neutrons or other nuclear effects.<ref>{{harvnb|Mallove|1991|p=246-248}}</ref>


In February 2002, the U.S. Navy revealed that its researchers had been studying cold fusion on the quiet more or less continuously since 1989. Researchers at their [[Space and Naval Warfare Systems Center]] in [[San Diego, California]] released a two-volume report, entitled "Thermal and nuclear aspects of the Pd/D<sub>2</sub>O system," with a plea for proper funding.<ref>{{harvnb|Mullins|2004}}</ref>
In February 2002, the U.S. Navy revealed that its researchers had been studying cold fusion on the quiet more or less continuously since 1989. Researchers at their [[Space and Naval Warfare Systems Center]] in [[San Diego, California]] released a two-volume report, entitled "Thermal and nuclear aspects of the Pd/D<sub>2</sub>O system," with a plea for proper funding.<ref>{{harvnb|Mullins|2004}}</ref>
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=== Nuclear transmutations ===
=== Nuclear transmutations ===
There have been reports that small amounts of copper and other metals can appear within Pd electrodes.<ref name="Storms_2007_93_95">{{harvnb|Storms|2007|p=93-95}}</ref> Iwamura et al. report transmuting Cs to Pr and Sr to Mo, with the mass number increasing by 8, and the atomic number by 4 in either case.<ref name="IwamuraSakanoItoh_2002_full">{{harvnb|Iwamura|Sakano|Itoh|2002|pp=4642-4650}}</ref>. Cs or Sr was applied to the surface of a Pd complex consisting of a thin Pd layer, alternating CaO and Pd layers, and bulk Pd. Deuterium was diffused through this complex. The surface was analyzed periodically with [[X-ray photoelectron spectroscopy]] and at the end of the experiment with glow discharge mass spectrometry.<ref name="IwamuraSakanoItoh_2002_full">{{harvnb|Iwamura|Sakano|Itoh|2002|pp=4642-4650}}</ref> Production of such heavy nuclei is so unexpected from current understanding of nuclear reactions that extraordinary experimental proof will be needed to convince the scientific community of these results.<ref>{{harvnb|Schaffer|1999|Ref=Saeta1999|p=2}}</ref>
There have been reports that small amounts of copper and other metals can appear within Pd electrodes.<ref name="Storms_2007_93_95">{{harvnb|Storms|2007|p=93-95}}</ref> Iwamura et al. report transmuting Cs to Pr and Sr to Mo, with the mass number increasing by 8, and the atomic number by 4 in either case.<ref name="IwamuraSakanoItoh_2002_full">{{harvnb|Iwamura|Sakano|Itoh|2002|pp=4642-4650}}</ref>. Cs or Sr was applied to the surface of a Pd complex consisting of a thin Pd layer, alternating CaO and Pd layers, and bulk Pd. Deuterium was diffused through this complex. The surface was analyzed periodically with [[X-ray photoelectron spectroscopy]] and at the end of the experiment with glow discharge mass spectrometry.<ref name="IwamuraSakanoItoh_2002_full">{{harvnb|Iwamura|Sakano|Itoh|2002|pp=4642-4650}}</ref>


== Criticism ==
== Criticism ==
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=== Missing nuclear products ===
=== Missing nuclear products ===
The fusion of two [[deuterium]] nuclei usually produces either a [[tritium]] nucleus and a [[proton]], or a [[helium-3]] (<sup>3</sup>He) nucleus and a [[neutron]]. The level of neutrons, tritium and <sup>3</sup>He actually observed in the Fleischmann-Pons experiments have been well below the level expected in view of the heat generated, implying that these fusion reactions cannot explain it. If the excess heat were generated by the fusion of two deuterium nuclei into helium (<sup>4</sup>He), a reaction which is normally extremely rare, [[gamma ray]]s and helium (alpha particles) would be expected. In 1989, insufficient levels of helium (alpha particles) and gamma rays were observed to explain the excess heat.<ref name="DOE_1989_5_6">{{harvnb|US DOE|1989|Ref=DOE1989|pp=5-6}}</ref>

New information was presented in 2004 to the DOE review panel regarding the production of <sup>4</sup>He.<ref name="DOE_2004">{{harvnb|Hagelstein et al.|2004|Ref=DOE2004}}</ref> When members of the panel were asked about the evidence of low energy nuclear reactions, twelve of the eighteen did not feel that there was any conclusive evidence, five found the evidence "somewhat convincing", and one was entirely convinced. The evidence of D+D fusion was taken as convincing or somewhat convincing by some reviewers; for others the lack of consistency was an indication that the overall hypothesis was not justified. Contamination of apparatus or samples by air containing 4He was cited as one possible cause for false positive results in some measurements.<ref name="DOE_2004_3"/>
New information was presented in 2004 to the DOE review panel regarding the production of <sup>4</sup>He.<ref name="DOE_2004">{{harvnb|Hagelstein et al.|2004|Ref=DOE2004}}</ref> When members of the panel were asked about the evidence of low energy nuclear reactions, twelve of the eighteen did not feel that there was any conclusive evidence, five found the evidence "somewhat convincing", and one was entirely convinced. The evidence of D+D fusion was taken as convincing or somewhat convincing by some reviewers; for others the lack of consistency was an indication that the overall hypothesis was not justified. Contamination of apparatus or samples by air containing 4He was cited as one possible cause for false positive results in some measurements.<ref name="DOE_2004_3"/>


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=== Insufficient theoretical explanations ===
=== Insufficient theoretical explanations ===
Nuclear fusion in the laboratory normally requires temperatures of tens of millions of degrees. The 1989 DOE panel said that such "nuclear fusion at room temperature [...] would be contrary to all understanding gained of nuclear reactions in the last half century" and "it would require the invention of an entirely new nuclear process." <ref name="DOE_1989_37"/> but it also recognized that "the failure of a theory to account for cold fusion can be discounted on the grounds that the correct explanation and theory has not been provided",<ref name="DOE_1989_36"/> that is, the lack of a satisfactory explanation could not be used to dismiss experimental evidence.
Cold fusion researchers acknowledge the [[Cold fusion#Theoretical issues|theoretical issues]] and have proposed various speculative theories (for a full review, see {{harvnb|Storms|2007}}) to explain the reported observations. None has received mainstream acceptance.<ref name="Biberian_2007">{{harvnb|Biberian|2007}}</ref>

Cold fusion observations are contrary to the conventional physics of nuclear fusion in several ways :
* Nuclear reactions would occur at low temperatures if the nuclei could be forced close enough together. The average density of deuterium atoms that can be obtained in palladium is vastly insufficient for fusion to occur according to known mechanisms. The average distance is approximately 0.17 [[nanometer]]s, which is too far apart to allow a significant rate of fusion through quantum mechanical tunneling. In fact, this distance is farther than the separation of nuclei in D<sub>2</sub> gas molecules, which do not exhibit fusion.<ref name="DOE_1989_6_7">{{harvnb|US DOE|1989|Ref=DOE1989|pp=6-7}}</ref>
* There is no known mechanism that would release fusion energy as heat instead of radiation within the relatively small metal lattice.<ref name="Goodstein_1994_528">{{harvnb|Goodstein|1994|p=528}}</ref> The direct conversion of fusion energy into heat is not possible because of energy and [[momentum]] conservation and the laws of [[special relativity]].<ref name="Kee_1999_5">{{harvnb|Kee|1999|p=5}}</ref>

Cold fusion researchers acknowledge these issues and have proposed various speculative theories (for a full review, see {{harvnb|Storms|2007}}) to explain the reported observations, but none has received mainstream acceptance.<ref name="Biberian_2007">{{harvnb|Biberian|2007}}</ref>


==See also==
==See also==
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|year=1989
|year=1989
|doi=10.1016/0013-4686(89)85026-1}}
|doi=10.1016/0013-4686(89)85026-1}}
* {{citation |last=Kee |first=B
|title=What is the current scientific thinking on cold fusion? Is there any possible validity to this phenomenon?
|periodical=Scientific American
|date=October 21, 1999
|series=Ask the Experts
|url=http://www.sciam.com/article.cfm?id=what-is-the-current-scien
|accessdate = 2008-12-17
|doi=}}
* {{citation |last=Kozima |first=Hideo
* {{citation |last=Kozima |first=Hideo
|title=The Science of the Cold Fusion phenomenon
|title=The Science of the Cold Fusion phenomenon
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|pages=243, C4
|pages=243, C4
|doi= }}
|doi= }}
* {{citation |ref=Seata1999
|last=Seata |first=Peter N.
|last2=Schaffer |first2=Michael J.
|last3=Morrison |first3=Douglas R.O.
|last4=Heeter |first4=Robert F.
|title=What is the current scientific thinking on cold fusion? Is there any possible validity to this phenomenon?
|periodical=Scientific American
|date=October 21, 1999
|series=Ask the Experts
|url=http://www.sciam.com/article.cfm?id=what-is-the-current-scien
|accessdate = 2008-12-17}} - (each author writing separately)
* {{citation |ref=Scaramuzzi_2000
|last=Scaramuzzi|first=F.
|title=Ten years of cold fusion: an eye-witness account
|periodical=Accountability in Research,
|date=2000
|volume=8
|page=77
|accessdate = 2008-12-19}} - (page numbers refer to a blocked link to an authorized reprint)
*{{citation| last=Seife |first=Charles |authorlink=Charles Seife
*{{citation| last=Seife |first=Charles |authorlink=Charles Seife
|title=Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking
|title=Sun in a Bottle: The Strange History of Fusion and the Science of Wishful Thinking

Revision as of 20:01, 19 December 2008

Cold fusion experimental apparatus at the US Navy Space and Naval Warfare Systems Center San Diego (2005)

Cold fusion is a purported type of nuclear fusion in which fusion reactions occur at room temperature under special conditions. Whereas typical reactions require high temperatures or a known catalyst in order to overcome the repulsive forces that inhibit fusion, cold fusion is hypothesized to occur without these by use of special apparatus. The field is also known as low energy nuclear reactions (LENR) or condensed matter nuclear science.

The field gained attention in 1989, when Martin Fleischmann and Stanley Pons reported producing a tabletop nuclear fusion reaction at the University of Utah.[1] In their press conferences and papers, they reported the observation of anomalous heating ("excess heat") of an electrolytic cell during electrolysis of heavy water using palladium (Pd) electrodes, and proposed that this heating was caused by nuclear fusion of deuterium (D). Their report raised hopes of a cheap and abundant source of energy.[2]

Cold fusion gained a reputation as pathological science after several researchers presented reports of failed replication attempts at conferences and in journals, and because of the known difficulty of overcoming nuclear repulsion forces.[3] Cold fusion research continues,[4] but most scientists remain skeptical.[5]

The majority of a review panel organized by the US Department of Energy (DOE) in 1989 found that the evidence for the discovery of a new nuclear process was not persuasive. In 2004, the DOE convened a second cold fusion review panel which reached conclusions that were similar to those of the 1989 panel.[6]

History

Early work

The special ability of palladium to absorb hydrogen was recognized as early as the nineteenth century by Thomas Graham.[7] In the late nineteen-twenties, two Austrian born scientists, Friedrich Paneth and Kurt Peters (German Wikipedia article), originally reported the transformation of hydrogen into helium by spontaneous nuclear catalysis when hydrogen was absorbed by finely divided palladium at room temperature. However, the authors later acknowledged that the helium they measured was due to background from the air.[8][7]

In 1927, Swedish scientist J. Tandberg stated that he had fused hydrogen into helium in an electrolytic cell with palladium electrodes.[7] On the basis of his work, he applied for a Swedish patent for "a method to produce helium and useful reaction energy". After deuterium was discovered in 1932, Tandberg continued his experiments with heavy water. Due to Paneth and Peters' retraction, Tandberg's patent application was eventually denied.[7]

The term "cold fusion" was coined by E. Paul Palmer of Brigham Young University in 1986 in an investigation of "geo-fusion", or the possible existence of fusion in a planetary core.[9]

Fleischmann-Pons announcement

Fleischmann and Pons were invesitgating a hypothesis that collective effects in chemical processes, which would require quantum electrodynamics to calculate, might influence nuclear processes more than predicted by quantum mechanical calculations.[10]

Electrolysis cell schematic

Their experimental apparatus was a calorimeter, an insulated vessel used for measuring process heat. Within the vessel was a palladium cathode which they used for electrolysis of heavy water to produce deuterium and oxygen, which were allowed to leave the cell carrying along some heat. It was necessary to replenish the cell with heavy water at regular intervals.[1] A current was applied to the cell continuously for many weeks. For most of the time, the power input to the cell was equal to the energy leaving the cell within measurement accuracy, and the cell temperature was stable at around 30 °C. But then, at some point (and in some of the experiments), the temperature rose suddenly to about 50 °C without changes in the input power, for durations of 2 days or more. The generated power was significantly higher than the input power during these power bursts. Eventually the power bursts in any one cell would no longer occur and the cell was turned off.[1]

In 1988, Fleischmann and Pons applied to the United States Department of Energy for funding towards a larger series of experiments. Up to this point they had been funding their experiments using a small device built with $100,000 out-of-pocket.[11] The grant proposal was turned over for peer review, and one of the reviewers was Steven E. Jones of Brigham Young University.[11] Jones had worked on muon-catalyzed fusion for some time, and had written an article on the topic entitled "Cold nuclear fusion" that had been published in Scientific American in July 1987. Fleischmann and Pons and co-workers met with Jones and co-workers on occasion in Utah to share research and techniques. During this time, Fleischmann and Pons described their experiments as generating considerable "excess energy", in the sense that it could not be explained by chemical reactions alone.[12] They felt that such a discovery could bear significant commercial value and would be entitled to patent protection. Jones, however, was measuring neutron flux, which was not of commercial interest.[11] In order to avoid problems in the future, the teams appeared to agree to simultaneously publish their results, although their accounts of their March 6 meeting differ.[13]

In mid-March, both research teams were ready to publish their findings, and Fleischmann and Jones had agreed to meet at an airport on March 24 to send their papers to Nature via FedEx.[13] Fleischmann and Pons, however, broke their apparent agreement, submitting their paper to the Journal of Electroanalytical Chemistry on March 11, and disclosing their work via a press conference on March 23.[11] Jones, upset, faxed in his paper to Nature after the press conference.[13]

Reaction to the announcement

Fleischmann and Pons' anouncement drew wide media attention. Scores of laboratories in the United States and abroad attempted to repeat the experiments.[14] A few reported success, many others failure.[14] Even those reporting success had difficulty reproducing Fleischmann and Pons' results.[15] One of the more prominent reports of success came from a group at the Georgia Institute of Technology, which observed neutron production.[16]. The Georgia Institute group later retracted their announcement.[17] For weeks, competing claims, counterclaims and suggested explanations kept what was referred to as "cold fusion" or "fusion confusion" in the news.[18]

In May 1989, the American Physical Society held a session on cold fusion, at which were heard many reports of experiments that failed to produce evidence of cold fusion. At the end of the session, eight of the nine leading speakers stated they considered the initial Fleischmann and Pons' claim dead.[14]

In April 1989, Fleischmann and Pons published a "preliminary note" in the Journal of Electroanalytical Chemistry.[1] This paper notably showed a gamma peak without its corresponding Compton edge, which indicated they had made a mistake in claiming evidence of fusion byproducts.[19][20] The preliminary note was followed up a year later with a much longer paper that went into details of calorimetry but did not include any nuclear measurements.[12]

In July and November 1989, Nature published papers critical of cold fusion claims.[21][22]

Nevetherless, Fleischmann and Pons and a number of other researchers who found positive results remained convinced of their findings.[14] In August of 1989, the state of Utah invested $4.5 million to create the National Cold Fusion Institute.[23]

1989 DOE panel

The United States Department of Energy organized a special panel to review cold fusion theory and research.[24] In November of 1989, the panel issued its report, concluding that results as of that date did not present convincing evidence that useful sources of energy would result from phenomena attributed to cold fusion.[25] The panel noted the inconsistency of reports of excess heat and the greater inconsistency of reports of nuclear reaction byproducts. Nuclear fusion of the type postulated would be inconsistent with current understanding and would require the invention of an entirely new nuclear process. The panel was against special funding for cold fusion research, but supported modest funding of focused experiments within the general funding system."[26]

Further developments (1989-2004)

After the 1989 review by the DOE, cold fusion was generally seen as an example of pathological science. Science writers Robert L. Park and Gary Taubes have published books criticizing cold fusion experiments and researchers.[27][28]

In June 1990, Gary Taubes wrote an editorial in Science suggesting that Texas A&M cells might have been spiked with tritiated water.[29] A 3-professor panel of Texas A&M later found that none of the experiments were fraudulently conducted, saying that spiking was unlikely because scientists got different results when they tested the spiking theory by intentionally putting tritium in water.[30][31] John Bockris later published his side of the controversy and a defense of academic freedom in "Accountability in Research".[32]

In 1991, Eugene Mallove stated that the negative report issued by the MIT Plasma Fusion Center in 1989, which was highly influential in the controversy, was inaccurate. After lodging an official complaint, Mallove resigned from his post as chief science writer at the MIT news office on June 7, 1991.[33]

In 1991, researcher Andrew Riley was killed when a cold fusion cell exploded, possibly due to accumulation of deuterium gas and the failure of a safety valve.[34]

In September 1990, Fritz Will, Director of the National Cold Fusion Institute, compiled a list 92 groups of researchers from 10 different countries that had reported excess heat, tritium, helium4, neutrons or other nuclear effects.[35] Proponents estimate that 3,000 cold fusion papers have been published, [36] including over 1,000 journal papers and books, where the latter number includes both pro and con articles.[α]

Fleischmann and Pons relocated their laboratory to France under a grant from the Toyota Motor Corporation. The laboratory, IMRA, was closed in 1998 after spending £12 million on cold fusion work.[37]

A cold fusion calorimeter of the open type, used at the New Hydrogen Energy Institute in Japan. Source: SPAWAR/US Navy TR1862

Between 1992 and 1997, Japan's Ministry of International Trade and Industry sponsored a "New Hydrogen Energy Program" of US$20 million to research cold fusion. Announcing the end of the program, Hideo Ikegami stated in 1997 "We couldn't achieve what was first claimed in terms of cold fusion." He added, "We can't find any reason to propose more money for the coming year or for the future."[38]

In 1994, David Goodstein described cold fusion as "a pariah field, cast out by the scientific establishment. Between cold fusion and respectable science there is virtually no communication at all. Cold fusion papers are almost never published in refereed scientific journals, with the result that those works don't receive the normal critical scrutiny that science requires. On the other hand, because the Cold-Fusioners see themselves as a community under siege, there is little internal criticism. Experiments and theories tend to be accepted at face value, for fear of providing even more fuel for external critics, if anyone outside the group was bothering to listen. In these circumstances, crackpots flourish, making matters worse for those who believe that there is serious science going on here."[39]

Most people attempting to publish anything about the subject faced rejection of their papers.[citation needed] The late Nobel Laureate Julian Schwinger (1918 - 1994) was so outraged by the way the American Physical Society treated his papers that he resigned from that body in protest.[40] Cold fusion researchers said that cold fusion was being suppressed, and that skeptics suffered from "pathological disbelief".[41] They said that there was virtually no possibility for funding in cold fusion in the United States, and no possibility of getting published.[42] They said that people in universities refused to work on it because they would be ridiculed by their colleagues.[43]

To provide a forum for researchers to share their results, the first International Conference on Cold Fusion was held in 1990. The conference, recently renamed the International Conference on Condensed Matter Nuclear Science, is held every 12 to 18 months in various countries around the world. The periodicals Fusion Facts, Cold Fusion Magazine, Infinite Energy Magazine, and New Energy Times were established in the 1990s to cover developments in cold fusion and related new energy sciences. In 2004 The International Society for Condensed Matter Nuclear Science was formed "To promote the understanding, development and application of Condensed Matter Nuclear Science for the benefit of the public."

In February 2002, the U.S. Navy revealed that its researchers had been studying cold fusion on the quiet more or less continuously since 1989. Researchers at their Space and Naval Warfare Systems Center in San Diego, California released a two-volume report, entitled "Thermal and nuclear aspects of the Pd/D2O system," with a plea for proper funding.[44]

2004 DOE panel

In 2004, the DOE organized another panel to take a look at cold fusion developments since 1989 to determine if their policies towards cold fusion should be altered.[45] The resulting report stated, among other things, that: "Two-thirds of the reviewers ... did not feel the evidence was conclusive for low energy nuclear reactions, one found the evidence convincing, and the remainder indicated they were somewhat convinced." It also stated: "The nearly unanimous opinion of the reviewers in the 2004 review was that funding agencies should entertain individual, well-designed proposals for experiments that address specific scientific issues relevant to the question of whether or not there is anomalous energy production in Pd/D systems, or whether or not D-D fusion reactions occur at energies on the order of a few electron volts (eV). These proposals should meet accepted scientific standards and undergo the rigors of peer review. No reviewer recommended a focused federally funded program for low energy nuclear reactions."

In its conclusion, the report stated: "While significant progress has been made in the sophistication of calorimeters since the review of this subject in 1989, the conclusions reached by the reviewers today are similar to those found in the 1989 review." [46]

Recent developments

The reports of excess heat and anomalous tritium production[α] have been met by most scientists with skepticism,[47] although discussion in professional settings still continues. The American Chemical Society's (ACS) 2007 conference in Chicago held an "invited symposium" on cold fusion and low-energy nuclear reactions, and thirteen papers were presented at the "Cold Fusion" session of the March 2006 American Physical Society (APS) Meeting in Baltimore.[48][49] Articles supporting cold fusion have been published in peer reviewed journals such as Naturwissenschaften, Japanese Journal of Applied Physics, European Physical Journal A, European Physical Journal C, International Journal of Hydrogen Energy, Journal of Solid State Phenomena, Journal of Electroanalytical Chemistry, and Journal of Fusion Energy.[50]

In 2007, a United States Naval Research Laboratory researcher with no previous experience with cold fusion wrote a review of experiments with solid palladium cathodes and electrolytes with deuterium, or with D2 gas loaded in palladium powders. The author said that more than 10 groups worldwide have reported the measurement of excess heat in 1/3 of their experiments and that most of the research groups have reported occasionally seeing 50-200% excess heat for hours to days. The positive results were difficult to reproduce, which the author attributed to variations in the loading ratios of deuterium to palladium achieved by different research teams.[51]

In 2008, the government of India reviewed the field.[52] M. R. Srinivasan, former chairman of the Atomic Energy Commission of India said: "There is some science here that needs to be understood. We should set some people to investigate these experiments. There is much to be commended for the progress in the work. The neglect should come to an end".[53]

Field overview

An experimental cold device usually includes:

Cold fusion researchers have reported observing excess heat, X-rays, gamma rays, neutrons, protons, helium-4, helium-3, and/or "anomalous" isotopic distributions.[55][56], although many of the findings are not published in reputable journals or subjected to mainstream scrutiny. No experiment has unequivocally produced a particle emission spectrum matching that predicted by nuclear science. There is still no theory explaining cold fusion that has been accepted by the scientific community, but many explanations have been proposed. [55]

Excess heat

The excess power observed in some experiments is theorized to be beyond that attributable to ordinary chemical or solid state sources, or measurement error. Proponents attribute this excess power to nuclear fusion reactions.[45][51] In addition to Fleischmann and Pons, the generation of excess heat has been reported by others in various venues.[57][58][59][60][61][62]

In 1993, Fleischmann reported "heat-after-death" experiments: he observed the continuing generation of excess heat after the electric current supplied to the electrolytic cell was turned off.[63] Such observations have been reported by others.[64][65]

The cold fusion researchers who presented their review document to the 2004 DOE panel said that "the hypothesis that the excess heat effect arises only as a consequence of errors in calorimetry was considered, studied, tested, and ultimately rejected".[66]

Nuclear products

A CR-39 detector showing possible nuclear activity in cold fusion experiments at SSC San Diego.[67]

The cold fusion researchers who presented their review document to the 2004 DOE panel on cold fusion proposed that there were insufficient chemical reaction products to account for the excess heat.[68]However, the amount of helium in the gas stream was about half of what would be expected for a heat source of the type D + D → 4He.

Cold fusion researchers have also reported detection of many kinds of radiation: alpha, beta, gamma, proton, and triton. However, neutrons and other energetic emissions were never found in quantities commensurate with the excess heat, as would be expected by established theories of nuclear physics. This has led some cold fusion proponents to conjecture that new processes may be converting nuclear energy directly to heat.[68]

In 2007, the Space and Naval Warfare Systems Center San Diego reported their observation of pits in CR-39 detectors during D/Pd co-deposition experiments in the European Physical Journal. They said that those pits have features consistent with those observed for nuclear-generated tracks, that the Pd cathode is the source of those pits, and that they are not due to contamination or chemical reactions. They attributed some pits to knock-ons due to neutrons, and said that other pits are consistent with those obtained for alpha particles.[69] Further analysis of "triple pits" suggests that Deuterium-Tritium reactions occurring inside the Pd lattice produce neutrons with an energy above 9.6 MeV.[70]

Nuclear transmutations

There have been reports that small amounts of copper and other metals can appear within Pd electrodes.[71] Iwamura et al. report transmuting Cs to Pr and Sr to Mo, with the mass number increasing by 8, and the atomic number by 4 in either case.[72]. Cs or Sr was applied to the surface of a Pd complex consisting of a thin Pd layer, alternating CaO and Pd layers, and bulk Pd. Deuterium was diffused through this complex. The surface was analyzed periodically with X-ray photoelectron spectroscopy and at the end of the experiment with glow discharge mass spectrometry.[72]

Criticism

In the original 1989 DOE review,[73] skepticism towards cold fusion focused on four issues: the precision of calorimetry, the lack of consistently reproducible results, the absence of nuclear products in quantities consistent with the excess heat, and the lack of a mainstream theoretical mechanism. In the subsequent years considerable efforts have been made on these fronts. Today these issues still remain the focus of criticisms.

Precision and accuracy of calorimetry

In the first years after the Fleishmann-Pons announcement various challenges were put forth. The efficacy of the stirring method in the Fleischmann-Pons experiment, and thus the validity of the temperature measurements was disputed by Browne.[74] The experiment has also been criticized by Wilson.[75] The possibility that electrochemically mediated deuterium-oxygen recombination can cause the appearance of excess heat was discussed by Shkedi[76] and Jones.[77]

The 2004 DOE panel noted that "significant progress has been made in the sophistication of calorimeters since ... 1989", and summarized that "Evaluations by the reviewers ranged from: 1) evidence for excess power is compelling, to 2) there is no convincing evidence that excess power is produced when integrated over the life of an experiment. The reviewers were split approximately evenly on this topic."[45]

The panel continued, "Many reviewers noted that poor experiment design, documentation, background control and other similar issues hampered the understanding and interpretation of the results presented". The reviewers who did not find the production of excess power convincing said that excess power in the short term is not the same as net energy production over the entire time of an experiment, that such short-term excess power is only a few percent of the total external power applied and hence calibration and systematic effects could account for the purported effect, that all possible chemical and solid state causes of excess heat had not been investigated and eliminated as an explanation, that the magnitude of the effect had not increased after over a decade of work.

Kirk Shanahan suggested that a calibration constant shift could explain apparent excess heat signals, and that such a shift could occur by a redistribution of heat in a F&P cell. He further speculated that such a redistribution would occur if recombination at the electrode became active, but acknowledged that this is not experimentally proven.[78][79] Cold fusion proponents say that such speculations are not supported by experimental results (in particular, that the measured volume of recombined output evolved gases does not allow for recombination within the cell)[65] a statement that Shanahan's papers dispute.[78][80][79]

Lack of reproducibility of excess heat

In 1989, the DOE panel noted that "Even a single short but valid cold fusion period would be revolutionary. As a result, it is difficult convincingly to resolve all cold fusion claims since, for example, any good experiment that fails to find cold fusion can be discounted as merely not working for unknown reasons." [25].

The cold fusion researchers who presented their review document to the 2004 DOE panel on cold fusion said that the observation of excess heat has been reproduced, that it can be reproduced at will under the proper conditions, and that many of the reasons for failure to reproduce it have been discovered.[81] Contrary to these assertions, most reviewers stated that the effects are not repeatable, the magnitude of the effect has not increased in over a decade of work, and that many of the reported experiments were not well documented. [82]

Missing nuclear products

The fusion of two deuterium nuclei usually produces either a tritium nucleus and a proton, or a helium-3 (3He) nucleus and a neutron. The level of neutrons, tritium and 3He actually observed in the Fleischmann-Pons experiments have been well below the level expected in view of the heat generated, implying that these fusion reactions cannot explain it. If the excess heat were generated by the fusion of two deuterium nuclei into helium (4He), a reaction which is normally extremely rare, gamma rays and helium (alpha particles) would be expected. In 1989, insufficient levels of helium (alpha particles) and gamma rays were observed to explain the excess heat.[83]

New information was presented in 2004 to the DOE review panel regarding the production of 4He.[84] When members of the panel were asked about the evidence of low energy nuclear reactions, twelve of the eighteen did not feel that there was any conclusive evidence, five found the evidence "somewhat convincing", and one was entirely convinced. The evidence of D+D fusion was taken as convincing or somewhat convincing by some reviewers; for others the lack of consistency was an indication that the overall hypothesis was not justified. Contamination of apparatus or samples by air containing 4He was cited as one possible cause for false positive results in some measurements.[82]

An example of this was published by Clarke et al. in 2003.[85] Their paper reported on the analysis of gases found in four ‘Case-type’ cells obtained from the McKubre group at SRI International, a primary cold fusion research group. The Abstract states: “One sample appears to be identical in composition to air, and the other three have been seriously affected by leak(s) into and from the SRI cells.” The Conclusions states: "The samples of gas from Case-type cells provided to us by the SRI workers do not show any evidence of production of 4He via cold fusion. Our analytical results can be explained by a combination of two factors: (a) severe leak(s) that allowed air into the cells, and also caused removal of gases including hydrogen from the cells to the atmosphere, and (b) the action of the Pd/C catalyst on O2 in the incoming air, which resulted in high CO and CO2 concentrations—telltale fingerprints of chemical combination of atmospheric O2 and C in the catalyst."

Insufficient theoretical explanations

Nuclear fusion in the laboratory normally requires temperatures of tens of millions of degrees. The 1989 DOE panel said that such "nuclear fusion at room temperature [...] would be contrary to all understanding gained of nuclear reactions in the last half century" and "it would require the invention of an entirely new nuclear process." [26] but it also recognized that "the failure of a theory to account for cold fusion can be discounted on the grounds that the correct explanation and theory has not been provided",[25] that is, the lack of a satisfactory explanation could not be used to dismiss experimental evidence.

Cold fusion observations are contrary to the conventional physics of nuclear fusion in several ways :

  • Nuclear reactions would occur at low temperatures if the nuclei could be forced close enough together. The average density of deuterium atoms that can be obtained in palladium is vastly insufficient for fusion to occur according to known mechanisms. The average distance is approximately 0.17 nanometers, which is too far apart to allow a significant rate of fusion through quantum mechanical tunneling. In fact, this distance is farther than the separation of nuclei in D2 gas molecules, which do not exhibit fusion.[86]
  • There is no known mechanism that would release fusion energy as heat instead of radiation within the relatively small metal lattice.[87] The direct conversion of fusion energy into heat is not possible because of energy and momentum conservation and the laws of special relativity.[88]

Cold fusion researchers acknowledge these issues and have proposed various speculative theories (for a full review, see Storms 2007) to explain the reported observations, but none has received mainstream acceptance.[89]

See also

References

  1. ^ a b c d Fleischmann & Pons 1989, p. 301
  2. ^ Browne 1989, para. 1
  3. ^ Voss 1999, Platt 1998, Close 1992, Huizenga 1993, Taubes 1993, Goodstein 1994
  4. ^ Hagelstein et al. 2004,Van Noorden 2007
  5. ^ Beaudette 2002, Feder 2005, Hutchinson 2006, Kruglinksi 2006, Biberian 2007
  6. ^ Choi 2005, Feder 2005, US DOE 2004
  7. ^ a b c d US DOE 1989, p. 7
  8. ^ Paneth and Peters 1926
  9. ^ Kowalski 2004, II.A2
  10. ^ Leggett 1989
  11. ^ a b c d Crease & Samios 1989, p. V1
  12. ^ a b Fleischmann et al. 1990, p. 293
  13. ^ a b c Lewenstein 1994, p. 8
  14. ^ a b c d Browne 1989
  15. ^ Kee 1999, p. 1
  16. ^ Broad 1989
  17. ^ Wilford 1989
  18. ^ Bowen 1989
  19. ^ Tate 1989, p. 1
  20. ^ Platt 1998
  21. ^ Gai et al. 1989, pp. 29–34
  22. ^ Williams et al. 1989, pp. 375–384
  23. ^ Joyce 1990
  24. ^ US DOE 1989, p. 39
  25. ^ a b c US DOE 1989, p. 36
  26. ^ a b US DOE 1989, p. 37
  27. ^ Taubes 1993
  28. ^ Park 2000
  29. ^ Taubes 1990
  30. ^ New York Times 1990
  31. ^ Storms 1990
  32. ^ Bockris 2000
  33. ^ Brooks 2008, p. 65
  34. ^ Charles 1992
  35. ^ Mallove 1991, p. 246-248
  36. ^ Anderson 2007
  37. ^ Voss 1999
  38. ^ Pollack 1997, p. C4
  39. ^ Goodstein 1994
  40. ^ Storms 2007
  41. ^ Josephson 2004
  42. ^ Feder 2004, p. 27
  43. ^ Rusbringer 2005
  44. ^ Mullins 2004
  45. ^ a b c US DOE 2004, p. 3
  46. ^ US DOE 2004, p. 5
  47. ^ Feder 2005
  48. ^ Van Noorden 2007, para. 2
  49. ^ Chubb et al. 2006
  50. ^ Di Giulio 2002
  51. ^ a b Hubler 2007
  52. ^ Jayaraman 2008
  53. ^ Srinivasan 2008
  54. ^ Storms 2007, p. 144-150
  55. ^ a b Biberian 2007
  56. ^ [α]
  57. ^ Oriani et al. 1990, pp. 652–662, cited by Storms 2007, p. 61
  58. ^ Bush et al. 1991, cited by Biberian 2007
  59. ^ e.g. Storms 1993, Hagelstein et al. 2004
  60. ^ Miles et al. 1993
  61. ^ e.g. Arata & Zhang 1998, Hagelstein et al. 2004
  62. ^ Gozzi 1998, cited by Biberian 2007
  63. ^ Fleischmann 1993
  64. ^ Mengoli 1998
  65. ^ a b Szpak 2004
  66. ^ Hagelstein et al. 2004, p. 1
  67. ^ Mosier-Boss, Szpak & Gordon 2007, slide 7
    reported in Krivit 2007, p. 2
  68. ^ a b Hagelstein et al. 2004, p. 7
  69. ^ Mosier-Boss et al. 2007
  70. ^ Mosier-Boss et al. 2008
  71. ^ Storms 2007, p. 93-95
  72. ^ a b Iwamura, Sakano & Itoh 2002, pp. 4642–4650
  73. ^ US DOE 1989, pp. 6–8
  74. ^ Browne 1989, para. 16
  75. ^ Wilson 1992
  76. ^ Shkedi et al. 1995
  77. ^ Jones et al. 1995, p. 1
  78. ^ a b Shanahan 2002
  79. ^ a b Shanahan 2006
  80. ^ Shanahan 2005
  81. ^ Hagelstein et al. 2004, p. 14
  82. ^ a b US DOE 2004, p. 3
  83. ^ US DOE 1989, pp. 5–6
  84. ^ Hagelstein et al. 2004
  85. ^ Clarke 2003
  86. ^ US DOE 1989, pp. 6–7
  87. ^ Goodstein 1994, p. 528
  88. ^ Kee 1999, p. 5
  89. ^ Biberian 2007

Bibliography

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