Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!caip!meccts!mvs From: mvs@meccts.UUCP (Michael V. Stein) Newsgroups: net.politics,net.sci,net.physics Subject: Re: Nuclear power: the fast breeder Message-ID: <495@meccts.UUCP> Date: Sat, 23-Aug-86 21:07:43 EDT Article-I.D.: meccts.495 Posted: Sat Aug 23 21:07:43 1986 Date-Received: Sun, 24-Aug-86 03:43:32 EDT References: <546@gargoyle.UUCP> <521@dg_rtp.UUCP> <551@gargoyle.UUCP> <492@meccts.UUCP> <554@gargoyle.UUCP> Reply-To: mvs@meccts.UUCP (Michael V. Stein) Organization: MECC Technical Services Lines: 123 Xref: mnetor net.politics:9336 net.sci:1251 net.physics:2756 [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