[ RadSafe ] BAD INFORMATION

Sat Nov 15 19:32:01 CST 2008

Nov. 15

         Thank you, Roger, for this very informative posting.

Steven Dapra


At 03:17 PM 11/15/08 -0800, Roger Helbig wrote:
>Radiation Effects Research Foundation has extensive information about
>Hiroshima and Nagasaki, the victims and the cities today --
>http://www.rerf.or.jp/general/qa_e/index.html
>
> >>From the FAQ
>
>12 Are Hiroshima and Nagasaki still radioactive?
>
>The practical answer is, "No."
>
>People often ask, "If uranium and plutonium pose a potential hazard in
>nuclear waste sites and were present at dangerous levels in the environment
>following the Chernobyl nuclear accident, why aren't Hiroshima and Nagasaki
>still uninhabitable?"
>
>There are two ways residual radioactivity is produced from an atomic blast.
>The first is due to fallout of the fission products or the nuclear material
>itself--uranium or plutonium (uranium was used for the Hiroshima bomb
>whereas plutonium was used for the Nagasaki bomb)--that contaminate the
>ground. Similar ground contamination occurred as a consequence of the
>Chernobyl accident, but on a much larger scale (click here for more-detailed
>explanation). The second way residual radioactivity is produced is by
>neutron irradiation of soil or buildings (neutron activation), causing
>non-radioactive materials to become radioactive.
>
>Fallout. The Hiroshima and Nagasaki bombs exploded at altitudes of 600
>meters and 503 meters, respectively, then formed huge fireballs that rose
>with the ascending air currents. About 10% of the nuclear material in the
>bombs underwent fission; the remaining 90% rose in the atmosphere with the
>fireball. Subsequently, the material cooled down and some of it started to
>fall with rain (black rain) in the Hiroshima and Nagasaki areas, but
>probably most of the remaining uranium or plutonium was dispersed widely in
>the atmosphere. Because of the wind, the rain did not fall directly on the
>hypocenters but rather in the northwest region (Koi, Takasu area) of
>Hiroshima and the eastern region (Nishiyama area) of Nagasaki.
>
>The maximum estimates of dose due to fallout are 0.01-0.03 Gy in Hiroshima
>and 0.2-0.4 Gy in Nagasaki. The corresponding doses at the hypocenters are
>believed to be only about 1/10 of these values.
>
>Nowadays, the radioactivity is so miniscule that it is difficult to
>distinguish from trace amounts (including plutonium) of radioactivity caused
>by worldwide fallout from atmospheric (as opposed to underground)
>atomic-bomb tests that were conducted around the world in past decades,
>particularly in the 1950's and 1960's.
>
>Neutron activation. Neutrons comprised 10% or less of the A-bomb radiation,
>whereas gamma rays comprised the majority of A-bomb radiation. Neutrons
>cause ordinary, non-radioactive materials to become radioactive, but gamma
>rays do not. The bombs were detonated far above ground, so neutron induction
>of radioactivity on the ground did not produce the degree of contamination
>people associate with nuclear test sites (Nevada test site in Southwest US,
>Maralinga test site in South Australia, Bikini and Mururoa Atolls, etc.).
>
>Past investigations suggested that the maximum cumulative dose at the
>hypocenter from immediately after the bombing until today is 0.8 Gy in
>Hiroshima and 0.3-0.4 Gy in Nagasaki. When the distance is 0.5 km or 1.0 km
>from the hypocenter, the estimates are about 1/10 and 1/100 of the value at
>the hypocenter, respectively. The induced radioactivity decayed very quickly
>with time. In fact, nearly 80% of the above-mentioned doses were released
>within a day, about 10% between days 2 and 5, and the remaining 10% from day
>6 afterward. Considering the extensive fires near the hypocenters that
>prevented people from entering until the following day, it seems unlikely
>that any person received over 20% of the above-mentioned dose, ie, 0.16 Gy
>in Hiroshima and 0.06-0.08 Gy in Nagasaki.
>
>As for Hiroshima and Nagasaki proper, the longest-lasting induced
>radionuclide that occurred in amounts sufficient to cause concern was
>cesium-134 (with a half-life of about 2 years). Most of the induced
>radioactivities from various radionuclides decayed very quickly so that it
>now takes considerable time and effort to measure it using highly sensitive
>equipment. Despite such miniscule levels, measurements of residual
>radioactivity using recently developed ultra-sensitive techniques have been
>utilized to estimate neutron doses released from the bombs and have formed
>part of the basis of the latest atomic-bomb dosimetry (DS02).
>
>Although the levels of residual radioactivity at the hypocenters in
>Hiroshima and Nagasaki were initially high, they declined quickly and are
>now far less than the dose received from background radiation. Hence, there
>is no detectable effect of present-day residual radiation on human health.
>In fact, today both Hiroshima and Nagasaki are thriving cities with large
>populations.
>
>-----Original Message-----
>From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
>Of Franz Schönhofer
>Sent: Saturday, November 15, 2008 10:01 AM
>To: 'George Stanford'; 'Peterson, Ken'
>Cc: radsafe at radlab.nl
>Subject: AW: [ RadSafe ] BAD INFORMATION
>
>George,
>
>Having been interested in nuclear bomb topics since many years I find your
>comment unacceptable, sloppy and simply unbelievable, that somebody who
>obviously regards himself as a member of the community of radiation
>protection professionals distributes something like this on the RADSAFE
>list. Following your reasoning it must have been really funny to have been a
>victim of the Hiroshima bombing! Fission products can still be measured in
>Hiroshima as well as those from fallout. Could you give some sources for
>your unbelievable comment? There are more than enough who show facts
>contrary to your caimed ones. Interesting to read, that there is no local
>fallout - again please give sources for this nonsensicle claim? I have been
>the leader of the terrestrial working group of the International Mururoa
>Project on the Nuclear Tests of France in the South Pacific - what a
>surprise we found quite a lot of fission products on the atolls of Mururoa
>and Fangataufa. How can you dare to say, that there is no local fallout in a
>nuclear bomb explosion? (They were all of the type you call "air burst" and
>even more they were not above ground but above the lagoon. No "local
>fallout"? You are kidding!!!! - which is true for your claim that one need
>not worry, if one is not wounded. Neither Hiroshima nor Nagasaki were ground
>level bursts - don't you know that?
>
>I would really recommend that  y o u  get the facts straight. Read about the
>hundreds of thousands victims of both the Hiroshima and Nagasaki bombings
>and then stop distributing the nonsense you did. With my disdain for your
>unbelievable opinions
>
>Franz
>
>Franz Schoenhofer, PhD
>MinRat i.R.
>Habicherg. 31/7
>A-1160 Wien/Vienna
>AUSTRIA
>
>
>-----Ursprüngliche Nachricht-----
>Von: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] Im Auftrag
>von George Stanford
>Gesendet: Freitag, 14. November 2008 23:01
>An: Peterson, Ken
>Cc: radsafe at radlab.nl
>Betreff: Re: [ RadSafe ] BAD INFORMATION
>
>Ken:
>
>          The problem is somewhat more subtle.  The old brochures you
>link to clearly are bald-faced attempts to make the public think
>nuclear war is like a romp in the park.  However, while the sheets
>are simplistic in the extreme, and seriously misleading, all the
>statements are, in a literal sense, accurate.
>
>- "By the time the debris stops falling, there is no radiation
>hazard."  The statement is true. It is made in the context of a
>Hiroshima-type "air burst" (one in which the fireball does not touch
>the ground).  In such a case, all the radioactive fission products
>are carried upward -- there is no local fallout.  There is a small
>amount of radioactivity induced by neutrons near ground zero, but
>it's too low to be of concern, especially in a wartime context.
>
>-  "In most cases, if you are not wounded or burned, you need not
>worry about radiation."  This also is true, for the same reason.
>
>- "Or radiation exposure from airbursts can be avoided by maneuvering
>your ship or vehicle."  Certainly false, as you phrase it -- but the
>pamphlet doesn't say that.  If you read the footnote more carefully,
>you will see that the context is the aftermath of a ground-level
>burst -- so the footnote, while it might not be relevant, is
>literally accurate -- under the unlikely assumption, that is, that
>you know where the fallout has landed (covering perhaps many square
>miles) so that you can drive around it (good luck!).
>
>          Being from the late 40s or early 50s, presumably, those
>simplistic propaganda sheets assumed relatively small, Hiroshima-size
>(~15 kiloton) bombs.  They would be even more misleading (although
>still literally true) in these days of much larger, even more
>destructive, weapons.
>
>          Nuclear weapons are nasty, but we still need to get our
>facts straight.
>
>          Cheers,
>
>          George Stanford
>          Reactor physicist, retired
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>At 11:21 AM 11/14/2008, Peterson, Ken wrote:
>It is interesting to note how the US Government publishes erroneous
>information in the 1950's, and it STILL impacts the military and public
>today.  It would be funny if it weren't so serious.  Note that: "By the
>time the debris stops falling, there is no radiation hazard.", "In most
>cases, if you are not wounded or burned, you need not worry about
>radiation."  Or radiation exposure from airbursts can be avoided by
>maneuvering your ship or vehicle.....
>
>http://www.safetycenter.navy.mil/photo/index.asp
>
>http://www.safetycenter.navy.mil/photo/images/images-301-350/photo313-1_high
>-res.jpg
>
>http://www.safetycenter.navy.mil/photo/images/images-301-350/photo313-2.jpg
>
>
>
>Ken Peterson