Bubble Fusion Vindicated in Flagship Nuclear Journal
Adapted by Joy Cernac and Sterling D. Allan
for Pure Energy Systems News
NOTE: Rusi Taleyarkhan, pictured above, was officially reprimanded, despite the NED peer-reviewed paper that vindicates Bubble Fusion. He will no longer have a named professorship at the university and will not fully supervise graduate students for three years. The announcement follows an unsuccessful appeal by Taleyarkhan against two counts of research misconduct: “He added a student’s name to papers to invoke a witness to the experiments, and stated falsely that his results had been independently confirmed.” (New Scientist; Aug. 28, 2008)
Bubble fusion, which in the last couple of years has come to be viewed with a jaundiced eye, has been cleared by a new peer-reviewed report that examines the faulty basis for the negative assessment.
A new scientific paper* on bubble fusion has been published by the multi-institutional team of Taleyarkhan, Lapinskas, Xu, Cho, Lahey and Nigmatulin under the international publishing house, Elsevier B.V., in the nuclear industry’s premier scientific journal, Nuclear Engineering and Design (NED).
The purpose of this new seminal paper is to undo misconceptions generated by University of California at Los Angeles (UCLA) researcher’s webposting, which was assumed as technically accurate and reported by Nature magazine in March of 2006.
Over the past two years, a methodical and systematic study was undertaken with the intense efforts of researchers from Purdue University, Rensselaer Polytechnic Institute, Russian Academy of Sciences, FNC Tech. of S. Korea together with input from Dr. West (retd. ORNL). This study was documented, using time-honored traditions, then offered for anonymous peer review, acceptance and publication in Nuclear Engineering and Design*.
The results of the new archival publication* confirm for the record that the confusion and controversies caused from past reports have resulted from neglect of important details within bubble fusion experiments. The new results demonstrate that neutron pulse pileup due to picosecond duration neutron pulse emission during bubble fusion events, ice-pack shielding between the detector and the fusion source, and gamma photon leakage all play important roles in affecting the spectra of neutrons from acoustic inertial confinement thermonuclear fusion experiments.
Bubble fusion :
Bubble fusion, also known as sonofusion, is the non-technical name for a nuclear fusion reaction hypothesized to occur during sonoluminescence, an extreme form of acoustic cavitation. Officially, this reaction is termed acoustic inertial confinement fusion (AICF) since the inertia of the collapsing bubble wall confines the energy, causing an extreme rise in temperature. The high temperatures sonoluminescence can produce raises the possibility that it might be a means to achieve thermonuclear fusion. At temperatures hot enough, atoms can literally fuse and release even more energy than when they split in nuclear fission, now used in nuclear power plants and weapons. Furthermore, fusion is clean in that it does not produce long-lived nuclear waste. (Wikipedia)
The new paper presents a comprehensive study that takes into account all six of the reported successful bubble fusion studies, including those associated with successful confirmations by groups unaffiliated with the original Taleyarkhan et al. research team. Two, unique, calibrated, validated and cross-checked methods were employed. Notably, in some of these successful bubble fusion experimental programs, ice-pack shielding was present between the reactor and detector. The goal was to address the confusion resulting from simulations conducted under incorrect experimental configurations and omission of key physics behind the bubble fusion phenomenon.
On March 8, 2006, Nature magazine unfortunately published an online article under the title, “Bubble bursts for table-top fusion; Data analysis calls bubble fusion into question”, by UCLA researchers, namely Brian Naranjo, under the supervision of Seth Putterman (doi:10.1038/news060306-3). This single, misinformed, unpublished, web-posted, non-peer reviewed article, which relied on sources with undisclosed conflicts of interest with competitors, set into motion a federally mandated two-year investigation. This article presented computer code simulation results for the anticipated neutron spectrum in bubble fusion experiments of Taleyarkhan et al. (PRL 96, Jan. 2006). This UCLA simulation was conducted for a guessed (without fact checking) experimental geometry, and it missed other attributes of bubble fusion phenomena in which neutrons of a fixed energy of 2.45 MeV from the bubble fusion nuclear reactor go whizzing past to a nearby detector with nothing in between. UCLA’s calculated neutron spectrum was shown to be very different from that published in the 2006 experimental report by Taleyarkhan et al., but resembled the overall features of a neutron energy spectrum from Californium-252. This is a commonly used laboratory radio-isotope, which spontaneously emits neutrons over a range of energies. The Nature March 8, 2006 article alleged actions that constitute fraud, bubble fusion data fabrication, and quoted UCLA’s B. Naranjo as stating: “The probability of getting such a poor match for neutrons produced by fusion is one in more than 100 Million –virtually impossible.” This webpost verdict from a UCLA graduate student was portrayed by the Nature reporter as true without accurately investigating the facts.
The resulting fallout was immense and extremely damaging to the Taleyarkhan et al. team, and severely damaged credibility of the bubble nuclear fusion field, bringing it to a virtual halt. An in-depth, federally mandated investigation of the incident has dismissed allegations related to scientific fraud and fabrication, and has supported validity of the discovery and it’s several successful replications. The two remaining Purdue University-based allegations (also apparently trumped up) are not aimed at the science and will take some time to resolve. In tandem, bubble fusion research and subsequent discoveries will continue to take place as these issues are resolved.
Taleyarkhan said “I can’t control the actions of the University in their unfortunate situation of having administrators and attorneys who place themselves ahead of the truth and importance of the science. This could happen to any other faculty member and is a sad precedent for the academic world. I can only move forward and remain positive”.
Upon careful examination by multiple researchers, it was found that UCLA’s computer modeling neglected to add a simple but crucial physical parameter: a ~1-inch piece of ice pack. Used as thermal shielding, this significant component should be placed between the bubble fusion reactor and the neutron detector, as specified for the experiments in the Taleyarkhan et al. 2006 PRL publication. Put simply, neutrons generated from fusion carry a momentum similar to bullets of a certain speed shot from a gun. If one measures fusion neutrons without shielding, the neutrons’ energy should be 2.45 MeV, analogous to the 1,000 fps velocity of bullets fired from a shotgun.
However, if one places a shield composed of steel balls between the gun and the target, some of the bullets will pass through the holes. Others will interact with the steel balls and slow down to various levels depending on the angle of attack, while still others may stick to the balls or create fragments. Consequently, the measured velocity of bullets leaving the shield will range from ~0 to 1,000 fps. The same applies to neutrons flying through a shield composed of water molecules. Neutrons are sub-atomic particles and much smaller than atoms of water. As in the bullet example, the neutrons emerging from the water molecule shield will also have a range of energies, along with other nuclear scale effects. This sort of “neutron” spectrum is deceptively similar to that from a radioisotope like Californium.
The UCLA researchers failed to include the ~1-inch piece of water ice-pack thermal shielding in their model. As a result, this omission and overlooking other aspects of bubble fusion physics has led to the publication of incorrect information in Nature that has been highly damaging to the fusion research industry.
To date, the world has not witnessed a comprehensive three-dimensional study of bubble fusion neutron transport processes.
# # #
Nuclear Engineering Design article reference
(*) Taleyarkhan, R.P., J. Lapinskas, Y. Xu, J. S. Cho, R. C. Block, R. T. Lahey,Jr., and R. I. Nigmatulin. Modeling, analysis and prediction of neutron emission spectra from acoustic cavitation bubble fusion experiments. Nucl.Eng.Des.(2008).doi:10.1016/i.nucengdes.2008.06.007.