APS News


Goal Must Be Nuclear-Free World

In response to “Public Affairs Report Examines Nuclear Weapons Policy”  (APS News, November 2008): The report appears to stress how to reinforce the US Nuclear Arsenal and how to induce other nations to reduce their Nuclear Arsenal. Such a biased approach can only lead to a catastrophe in the long run. One should start by stating that large Nuclear Arsenals are the foremost menace to the survival of humanity, and given that fact all nations should contemplate how to converge towards a world without Nuclear Weapons. That will necessarily involve the cooperation of all present and future Nuclear Powers.

Hopefully physicists should lead the way. I am optimistic that our next President may be sensitive to such issues.

Henry Blumenfeld
Gif sur Yvette, France

Ed. Note: The APS/AAAS/CSIS report, Nuclear Weapons in 21st Century U.S. National Security, calls for deeper reductions in the US and Russian arsenals while maintaining the safety, security, and reliability–with no new capabilities–of any remaining weapons. (The full report is available on the APS website.) In support of President-elect Obama׳s vision of nuclear weapons elimination, the APS Panel on Public Affairs is now considering a study to evaluate and substantially improve verification technology.  

Fusion Power Plant Dubbed Ridiculous

Nadia Ramlagan’s description of a 1 GW-day electrical D-T fusion power plant [“Bringing the Sun to Earth: Briefing Explains ITER Fusion Experiment,” November APS News] sounds benign and reasonable as compared to a coal burner. Arithmetic reveals the perfect fusion power plant is ridiculous and pestilent. D-T fusion yields a 3.5 MeV He-4 nucleus and a 14.1 MeV neutron. Stated daily emission of 0.5 lbs of 14.1 Mev neutrons sums to 7.3x1013 calories or 73 kilotonnes nuclear, 80% of the power plant’s fusion thermal output. Kinetic energy is recovered from neutral particles by inelastic collision (thermal neutrons continue to propagate) or nuclear reactions (lithium fission to tritium). The fusion reactor’s inner wall is an exercise of academic elegance, not reality. One GW-day thermal is 2x1013 calories. Where does 70% of the power plant’s thermal output go? 1.5 lbs of tritium/day, given 28.8 Ci/mmole specific activity, is 6.5 million gaseous curies/day. That is 2700 liters of gas at room temperature with a decay heat of 190,000 calories/hour (mean decay energy of 5.685 keV). The emperor is clothed in carbon nanotube fabric only visible to the worthy. Don’t stand downwind.

Al Schwartz
Irvine, CA

Imagining the Future of Scientific Software

Michael Nielsen (The Back Page,  APS News, November 2008) writes “We should ... create an open scientific culture where as much information as possible is moved ... onto the network ... [including] data, scientific opinion, questions, ideas, folk knowledge, workflows, and everything else.” He does not explicitly mention software, but it raises the question: What would ideal scientific software look like? I propose the following criteria: (1) free; (2) collaboratively built, (3) extensible; (4) self-contained; (5) modular; and (6) intellectually traceable. Of these conditions (1), (2) and (3) are, by now, banal. About (4), much existing freeware requires other freeware which requires other freeware. It isn’t necessarily backward compatible. I recently failed to port a code; along the way I found myself making a “software museum” of versions of GNU packages current at the time the code was frozen. About (5), it should be possible to use pieces of the whole without using the whole package. My personal example here is I found myself spending a month rewriting a code because I couldn’t disentangle a bit of it from a larger package; in particular, the initializations were diffused throughout over 250,000 lines of code in a common class statement. About (6), it should be possible to reconstruct the equations from comments in the code including references to journal articles.

My nightmare vision (and I need precious little imagination) is that a day comes in which we don't understand the codes we have, and we can’t fund their redevelopment because the problems have already been solved.
Zachary Levine
Rockville, MD

APS Report Short-changes Plug-in Hybrid Technology

My letter-to-the editor, “Plug-ins are a Panacea” (APS News, August-September 2008), pointed out that despite extensive propaganda to the contrary, batteries were not an obstacle to plug-in hybrid cars. Now, having read the APS Report, Energy Future: Think Efficiency, I have come to the disturbing conclusion that the Report itself constitutes part of the propaganda campaign against the plug-in hybrid: “Given the technical difficulties, plug-in hybrids will not replace the standard American family car in the near term.”

The referenced technical difficulties relate to the battery, which the Report says is not ready for prime time, based primarily on a private communication that the battery would add nearly $20,000 to the price of the vehicle from the expected cost of a new lithium ion battery going into the Chevy Volt by General Motors (GM), plus a projected five-to-ten-year learning curve to work out the glitches.

This despite the fact that both GM, with its EV-1, and Toyota, with its RAV4-EV, produced all-electric vehicles, whose nickel metal-hydride (NiMH) batteries could power them for 120 miles on a single charge. The GM EV-1's were later all shredded, but many of the Toyota EV’s are still on the road with their original batteries. Nothing in the Report indicates any reason why a battery suitable for an all-electric vehicle would not work in a plug-in hybrid, which only requires a 40-mile trip on a charge.

However, the NiMH batteries used in these vehicles, the Panasonic EV-95, are no longer in production. GM bought the patents for them in 1994, sued Panasonic, and recovered $30 million, after which the line of EV-95 batteries was shut down. In 2000, GM sold their control of EV batteries to Texaco, which became part of Chevron, and that’s where it stands now.

Thus it appears that the problem with batteries is legal and political, not technical.

The panel which prepared the Report knew or should have known about these matters and addressed them. Had they done so, they would have been compelled to arrive at substantially different conclusions and recommendations regarding plug-in hybrids, which are indeed a panacea, as the Report implicitly acknowledges.

These are serious issues. The Big Three automakers are seeking large amounts of money from the government. When they sit down with President-elect Obama, they will be armed with the Report, with the imprimatur of the American Physical Society, to show that plug-in hybrids are not ready for the market. Thus the APS will have been used by the Big Three and Big Oil to assist in another giant ripoff of the taxpayer, the consumer, the planet, and yes, national security.

Robert Levy
El Paso, TX

Burton Richter Responds

Ed. Note: We asked Burton Richter, who chaired the APS study group that produced the energy efficiency report, to comment on the above letter. Here is his reply.

Robert Levy seems to think the APS energy efficiency report was too negative about the state of the batteries required for plug-in hybrid vehicles (PHEVs). On the contrary, the report was, I thought, clear that we regarded PHEVs as one of the most important developments in the automotive industry to reduce both gasoline consumption and emissions. We did say that if all the light vehicles were plug-ins with a 40 mile electric range, gasoline consumption would decrease by 60%

What the report meant  to say about the batteries for the Chevy Volt is that they are the first generation of a new Li-Ion battery and as such are not likely to be good enough for the FULL span of all the light vehicles on the road. When they first appear they will be expensive and will need the kind of real life testing that comes from having a fleet of Chevy Volts running. General Motors has not announced prices yet, but as reported in the auto press, the cost of a Volt is likely to be around $40,000. I expect that within 5 to 10 years battery manufacturers will have worked their way down the learning curve and they will be suitable for all the light vehicle fleet. Perhaps we were not clear enough. 

My wife had the all electric GM EV-1. When they first appeared they could only go about 60 miles with their first generation of batteries. When we got ours, they were using Ni metal hydride batteries and could go 120 miles on a charge. Its lease cost was about the same as a Mercedes sedan. Over the 3 years we had the EV-1, it was recalled for software and firmware fixes six times and for hardware fixes twice. I don't expect miracles from the Volt, but I do expect plug-ins to take over as the technology matures.

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Editor: Alan Chodos
Associate Editor: Ernie Tretkoff