[ RadSafe ] 250K microSv

Mark Ramsay mark.ramsay at ionactive.co.uk
Wed Jun 15 23:08:41 CDT 2011

Same thing with activity too...

Suppose you say the activity is now 'twice' what it was before (e.g.
1TBq is now 2TBq). That might seem significant, but perhaps not so if
working in the PBq range.


-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Perle, Sandy
Sent: 16 June 2011 04:08
To: The International Radiation Protection (Health Physics) Mailing List
Subject: Re: [ RadSafe ] 250K microSv

Hi Steve,

I believe your assessment to be accurate. It's a nice trick to scare the
daylights out of the general public who don't understand radiation but
large numbers, implying very serious consequences. The use of mSv would
have been more appropriate but the effect would have been minimized. It
also possible that this is the graphic that was provided to the reporter
since I have seen that graphic used in many venues.

In our international dose reporting we report in units of mSv and there
have been occasions when communicating with some of our Japanese
colleagues they move the discussion to uSv. I don't have a problem is
discussing exposure, the use of uSv/hr is OK, but not when it comes to
dose and possible effect. Those who insist on large uSv values do play
into the mind game.



Sander C. Perle
Mirion Technologies
Dosimetry Services Division
2652 McGaw Avenue
Irvine, CA 92614

+1 (949) 296-2306 (Office)
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Mirion Technologies: http://www.mirion.com/

On 6/15/11 7:16 PM, "Steven Dapra" <sjd at swcp.com> wrote:

>June 15
>       A June 14 article in the Wall Street Journal [1] displays a
>quasi-graph of radiation exposure in general, and exposure to the
>Fukushima workers.  The graph uses microsieverts for its units.
>       A marker bar at 50,000 uSv notes that this is the "Normal annual
>exposure limit for radiation workers in Japan."  The next bar is at
>100,000 uSv.  At this level of exposure, the graph says, "the chances
>of getting cancer rise slightly.  Normally, exposure for Japanese
>radiation workers can't go above this level during a five-year period."
>       Farther up the graph, we are told that "Plant operator Tepco
>two workers may have logged exposure of 650,000 microsieverts."  The
>graph itself tops out at 250,000 uSv, "The new limit for Japanese
>workers dealing with a nuclear crisis like Fukushima Daiichi."
>       What's with the use of such a small unit?  Has the WSJ's writer
>bought into the anti-nuke histrionics of using minute units?  On a
>deeper level, do the WSJ copy editors and the writer actually believe
>the readers are such ignoramuses or non-sophisticates they can't do a
>little mental arithmetic and easily express these extravagant
>exposure levels in reasonable amounts?
>       What's really going on here?
>Steven Dapra
>1      Japanese Nuclear Cleanup Workers Detail Lax Safety Practices at
>Plant.  Phred Dvorak.  Wall Street Journal, June 14, 2011; pp. 1,
>continued on p. 12.
>       The link is
>       I have not tried the link.  I obtained it by doing a Google
>using the title of the article and the words "Wall Street Journal."
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