carnes@gargoyle.UUCP (Richard Carnes) (08/23/86)
[Michael Stein] > [Carnes] >>"Ralph Nader says nuclear reactors can blow up in a >>nuclear explosion" (Nader merely echoes the views of nuclear experts >>such as Brian Flowers who assert that fast breeders can undergo a >>nuclear explosion, although such an event ["Hypothetical Core >>Disruptive Accident"] is highly unlikely),... > >Completely wrong. If Nader was actually aware of Flower's work then >he was engaging in deception. If he was unaware of his work (the >most likely scenario), then he was simply ignorant. Sir Brian Flowers writes ["Nuclear Power", *Bull. Atom. Sci.*, March 1978, p. 24]: With any reactor employing a liquid coolant there is the risk that if, due to some malfunction, a substantial amount of fuel should melt, it could react with the coolant causing this to evaporate explosively and the core to be disrupted. It is highly improbable, but possible; and it is particularly serious for the fast breeder reactor because of the consequent risk, peculiar to this system, that the core somehow reassembles in a more reactive state than before. The result would be a very inefficient nuclear explosion, which if it also succeeded in breaching the reactor containment could cause damage one or two orders of magnitude more extensive than is envisaged for thermal reactors undergoing similarly improbable but disruptive malfunctions. This seems clear enough. The possibility of nuclear explosions in fast breeders is also acknowledged in two AEC documents: --AEC, Argonne Natl. Lab., *Liquid Metal Fast Breeder Reactor Program Plan*, Aug. 1968. --AEC, WASH-1535, Proposed Final Environmental Statement, *Liquid Metal Fast Breeder Reactor Program*, Dec. 1974. The former document estimates the energy yield of the accidents as equivalent to 300-500 pounds of TNT. >Energy scholar Nader made the following quote back in 1974: > > How many atomic explosions in our cities would you accept > before deciding that nuclear power is not safe - no > complexities, just a number! Mr. Stein gives no reference that would enable one to verify that Nader made this statement, and if so, what he meant by it. In *The Menace of Atomic Energy*, revised edition, p. 46, Nader states: "A water reactor cannot explode like a nuclear bomb -- its fuel does not contain a sufficient percentage of U-235 to make it weapons material." >This was long before breeder reactors were in our cities, since >breeder reactors aren't in US cities today. But it was long after the October 5, 1966, fuel melting accident at the Fermi breeder reactor near Detroit, which was more serious than the "maximum credible accident" for the plant. The title of the book *We Almost Lost Detroit* is a quotation from a nuclear engineer who was working at the plant. A 1957 University of Michigan study had concluded that a reactor accident at Fermi could kill 60,000 people. Richard Carnes
mvs@meccts.UUCP (Michael V. Stein) (08/24/86)
[I wrote] >>Energy scholar Nader made the following quote back in 1974: >> >> How many atomic explosions in our cities would you accept >> before deciding that nuclear power is not safe - no >> complexities, just a number! [Carnes writes] >Mr. Stein gives no reference that would enable one to verify that >Nader made this statement, and if so, what he meant by it. In *The >Menace of Atomic Energy*, revised edition, p. 46, Nader states: "A >water reactor cannot explode like a nuclear bomb -- its fuel does not >contain a sufficient percentage of U-235 to make it weapons >material." The reference I saw was a question asked by Nader to AEC Commissioner Doub at Ralph Nader's "Critical Mass" meeting. November, 1974. If Nader actually was aware that PWR cannot go critical, then he doesn't have the excuse of ignorance. The potential of a small explosion due to a superprompt critical condition in a fast breeder reactor has been known for a very long time. But the predicted size of such an unlikely explosion is on the order of hundreds of pounds of TNT. It is misleading to call it an atomic bomb when a small "Hiroshima" equivalent bomb is 20,000 *tons* of TNT. >But it was long after the October 5, 1966, fuel melting accident at >the Fermi breeder reactor near Detroit, which was more serious than >the "maximum credible accident" for the plant. The title of the book >*We Almost Lost Detroit* is a quotation from a nuclear engineer who >was working at the plant. A 1957 University of Michigan study had >concluded that a reactor accident at Fermi could kill 60,000 people. The "fuel melting incident" at Fermi I was caused by a coolant blockage of two of the 103 fuel subassemblies that comprised the core. The result was the melting of about 1% of the fuel. There was no difficulty in promptly shutting down the reactor, and all safety systems worked as expected. No radiation was released to the general public nor were there any health hazards to the workers at the plant. Later the reactor was repaired and resumed operation. The 1957 report I suspect that you are referring to is the "Report on the Possible Effects on the Surrounding Population of an Assumed Release of Fission Products into the Atmosphere from a 300-Megawatt Nuclear Reactor Located at Lagoona Beach, Michigan" (APDA-120). You somehow forgot to mention that the worst case health risks computed by APDA-120 assumed all of the fission products contained in over two tons of highly burned up reactor fuel were arbitrarily released to the outside environment as if the reactor vessel, primary shield tank, and containment building did not even exist. (Note, as part of the Defense in Depth philosophy, the containment at Fermi I was built to sustain far more pressure than what could be released through a secondary criticality accident (explosion). Also, the fission product activity at Fermi I was several thousand times lower than the activity assumed in APDA-120.) Even if all safeguards failed and enormous breaches to the containment somehow occured, there would still be natural mechanisms to reduce dispersion in the atmosphere such as plate-out of fission products on surfaces. Once such a release of radiation occured, there would have to be a temperature inversion combined with a slight wind to blow the radiation to Detroit before it dispersed. The worst case scenario in APDA-120 ignored all of these considerations. Uncritical use of such sources as Fuller's "We Almost Lost Detroit" does not advance the nuclear debate. Fuller's book is poor enough that it prompted those who reviewed the accident, to write a report refuting some of Fuller's more absurd claims. Their report was called, "We Did Not Almost Lose Detroit." A few quotes from this report might illustrate this point: [Fuller writes] "But as the control rods slowly withdrew, and the instrument readings reflected this silent power when the huge pumps sent the sodium syrup through the system, vibrations were felt in the floor of the control room that hinted at the reactors awesome power." While the description is certainly colorful and consistent with the images of impending disaster the author is trying to create, the vibrations from the primary sodium pumps could not be felt in the control room which is located in a separate building. The source of the term "sodium syrup" would be of interest since the viscosity of hot liquid sodium is about that of water. ... [Fuller writes} "Hundreds and hundreds of specifications like this had flowed through the process of putting this giant Swiss watch of a reactor together. And through it all, there could be no mistake. What if 0.1 gram of Uranium-236 got thrown out with the packing carton? Another colorful image to attempt to demonstrate the potential for disaster with the slightest slip. However, there were obviously mistakes made during the construction of Fermi-I. Fuller himself alludes to some of the difficulties with this first-of-a-kind reactor. The reference to 0.1 gram of U-236 being thrown out by mistake is confusing. The only U-236 at the site was microgram quantities in a fission counter. Perhaps U-235, the fissile fuel was the intention. In any case, the effect of throwing out 0.1 gram of either isotope would be inconsequential. ---- I have posted this message also to net.physics in the hope that someone more knowledgable about breeder reactors will respond. Specifically, I am interested in the current state of breeder research in the US, and around the rest of the world. -- Michael V. Stein Minnesota Educational Computing Corporation - Technical Services UUCP ihnp4!dicome!meccts!mvs
mc68020@gilbbs.UUCP (Thomas J Keller) (08/25/86)
In article <495@meccts.UUCP>, mvs@meccts.UUCP (Michael V. Stein) writes: > > The potential of a small explosion due to a superprompt critical > condition in a fast breeder reactor has been known for a very long > time. But the predicted size of such an unlikely explosion is on the > order of hundreds of pounds of TNT. It is misleading to call it an > atomic bomb when a small "Hiroshima" equivalent bomb is 20,000 > *tons* of TNT. No, it isn't. An "atomic bomb" is an explosive device which utilizes fissionable material as it's reactive source. A "small explosion due to a superprompt critical condition" as an explosion which is the result of fissionable material as the reactive source. No one here claimed that this explosion was in any way comparable to the Hiroshima bomb. It is dishonest and misleading for you to claim that such an explosion is *NOT* in fact the equivalent of a (very small) atomic bomb. You also neatly avoid the critical issue, which is that in such an explosion, the bulk of the fissionable material, along with *HUGE* quantities of highly radioactive by-products of the reactor operation, would be spewed directly (or indirectly) into the environment. > >But it was long after the October 5, 1966, fuel melting accident at > >the Fermi breeder reactor near Detroit, which was more serious than > >the "maximum credible accident" for the plant. The title of the book > >*We Almost Lost Detroit* is a quotation from a nuclear engineer who > >was working at the plant. A 1957 University of Michigan study had > >concluded that a reactor accident at Fermi could kill 60,000 people. > > The "fuel melting incident" at Fermi I was caused by a coolant > blockage of two of the 103 fuel subassemblies that comprised the core. > The result was the melting of about 1% of the fuel. There was no > difficulty in promptly shutting down the reactor, and all safety systems I beg your pardon? What sources do *YOU* have on the Fermi accident? According to all the information *I* have read, there was some particularly distressing difficulty in shutting the reactor down properly, and several of the safety systems in fact failed to operate. Fortunately, the man who was running the Fermi project was, unlike most people involved in the administration of nuclear power plant construction, an honest and dedicated individual, whose major goal *WAS* safety. Many of the safety systems *DID* work, and a total disaster was avoided. Had the design and construction of the Fermi plant been done the way contemporary plants are built, Detroit would be a ghosttown today. > worked as expected. No radiation was released to the general public > nor were there any health hazards to the workers at the plant. No radiation was released? **REALLY**??? Cite your sources for *THAT* tidbit, please. > Later the reactor was repaired and resumed operation. Incorrect. There were two reactors at the Fermi plant, and the second reactor was eventually brought into operation. As of 1979, the damaged reactor was still sitting there, awaiting final disposition. Moreover, several tens of drums of highly contaminated debris from the accident were still sitting piled up in an outhouse. Cite any evidence that the damaged reactor was in any way repaired. It was several *YEARS* before they even determined the exact cause of the Fermi accident (which, ironically, was the result of an attempt to further improve the safety of the reactor). > Uncritical use of such sources as Fuller's "We Almost Lost Detroit" > does not advance the nuclear debate. Fuller's book is poor enough > that it prompted those who reviewed the accident, to write a report > refuting some of Fuller's more absurd claims. Their report was called, > "We Did Not Almost Lose Detroit." And of course, Mr. Stein, the people who wrote this report had **NOTHING** to gain by so doing, right? There is **NO** possibility that perhaps they were attempting to cover something up? I am not saying that they *WERE*, only that the existence of such a report, as you have so aptly noted in response to postings citing reports inimical to nuclear energy, does *NOT* mean that the report is complete, correct or worthwhile. Quite rightly, you point out that many anti-nuclear activists are really quite ignorant of technical nuclear issues. Many are in fact actively resistant to learning about them. This was the major reason I divorced myself from the organized anti-nuclear groups. There are many anti-nuclear persons who are well qualified, however. Your ad hominem attacks on them only make you look as foolish as you are attempting to make them look. You continually make throuroughly ridiculous comments, such as the one a few articles back wherein you state that plutonium is "slightly radioactive" . Several nuclear physicists and engineers I know got a good chuckle out of **THAT** piece of dis-information. You insist that anti-nuclear activists have some hidden agenda (while failing to show what significant value any of them have to gain from their stance), yet explode in vehement outrage when someone suggests that those *WITHIN* the industry, who would very clearly have much to gain in insisting that their technology is safe, would deigm to mis-represent *ANYTHING*. An interesting, if somewhat distressing double standard. Let's face it, Mr. Stein, you are not interested in the truth, any more than you claim the anti-nukers are. You refuse to seriously consider *ANY* evidence that there could be serious problems with nuclear energy. You simply close your mind to any "expert" who doesn't agree with your pre- conceived notions on the subject. Your claims of relative safety for nuclear energy are deliberately misleading, your arguments about the possible effects of a serious accident in the processing, shipment and use of nuclear fuels are specious and dishonest. You either A) have something to gain from advancing nuclear energy (perhaps you have invested heavily in it?), or B) you have been thouroughly duped by the pro-nuclear proponents. The truth about the safety, necessity and desireability of nuclear energy is somewhere between your completely irresponsible attitudes and the completely irresponsible attitudes of many anti-nukers. I believe, however, that the truth lies somewhat closer to that espoused by the anti-nukers than it does to yours. -- Disclaimer: Disclaimer? DISCLAIMER!? I don't need no stinking DISCLAIMER!!! tom keller "She's alive, ALIVE!" {ihnp4, dual}!ptsfa!gilbbs!mc68020 (* we may not be big, but we're small! *)