Transcript Analysis of Radiation Dose Effects and Emergency Response

Learning from History
– Evacuation Criteria
Richard Wilson
Mallinckrodt Professor of Physics (Emeritus)
Harvard University
Friday, July 27th 2012
Kyoto, Japan
I first wish to thank the organizers of
this International Conference for inviting me
to come and tell you my opinions on the
tragic events that you have faced.
It is indeed a great pleasure to be here.
I am a small person and have always
been shorter than my friends and family.
So it is an especial pleasure to come to
a place where everyone is the right height!
In Any Situation
Compare Risk and Benefit
• This is done all the time, sometimes explicit
often implicit.
• If the situation changes (such as an
unexpected accident) a different Risk-Benefit
calculation is appropriate.
• True for any technology, nuclear or otherwise
• Best to have the calculation IN ADVANCE
so that panic does not set in
Effects of Radiation on people:
What do we know from previous incidents?
Those who do not understand history are condemned to repeat it
Medical X rays
Radium Dial painters
Hiroshima-Nagasaki
Windscale (UK)
TMI
Chernobyl
Tokai (Japan)
Theft of medical Source (Brazil)
Medical X rays
• The advantage of medical X rays is great
(one can see a fracture!)
• Physicians argued (correctly) in 1900 that
medical X rays were so beneficial that they
outweighed any adverse effect.
BUT
• The same benefit could be gained with 100
times less risk
• As late as 1980, X rays were done badly
Nuclear Power
in Ordinary Operation
• Radiation doses can be kept small both for the public
and for the workers very easily for a cost much less
than the cost of electricity
• Therefore a cost-benefit calculation says :
do so and make doses ALARA
(As Low As Reasonably Achievable)
• BUT when something out of the ordinary occurs
this calculation NO LONGER APPLIES
• The basic elements of a more appropriate calculation
can be found from basic science and from history and
should be understood in advance
Avoid Acute Radiation Syndrome (ARS)
ARS can occur if dose in a week is:
> 200 Rems (2 Sv).
It can result in death within a few days.
At 400 Rems (4 Sv) The guts are destroyed and
death soon follows.
Evacuation to avoid ARS is appropriate.
At Fukushima, no one in the public got ARS.
the highest exposed WORKER got 0.2 Sv
MORE RADIATION COULD HAVE BEEN ALLOWED
AS SOON AS ACCIDENT OCCURRED
Immediate Evacuation Unnecessary
Chronic Effects
Doses can accumulate over years
and chronic effects can be related to the
CUMULATIVE DOSE
cancer
heart disease
genetic effects
No cancers are caused specific to radiation
But radiation can cause an increase
in natural cancer rate
Perhaps 30% at 2 Sv (200 Rems)
(maybe much less)
What did history say one should do?
A big effect would be the chain:
• iodine drops on ground
• Cows eat the grass concentrate iodine in milk
• Children drink milk
• Concentrate in thyroid
SO BREAK THIS CHAIN AT ONCE
• Windscale (1957) confirmed that:
• Tell children not to drink local milk for a month
Not done early enough at Chernobyl
Immediate Actions
Planned in Advance
Allow radiation exposure standards to rise at
once to earlier allowed levels:
• 10 Rems (0.1 Sv) (average) per accident
• 80 Rems (0.8 Sv) for life saving activities
• 80 Rems (0.8 Sv) for an astronaut
• More for elderly volunteers
If no ARS then DO NOT EVACUATE AT ALL
for 2 days to allow a carefully considered wise
decision
First hydrogen explosion
• Wind was blowing out to sea! (Good)
• Evaluate effects at site boundary
(My evaluation was a day late waiting for the
numbers to be available in English or German)
My Estimate of Dose at Site Boundary
My Dose Calculation at Site Boundary
March 2012 Calculation
– The releases at first three days unimportant. But
those of Tuesday/Wednesday (after wind changed)
were crucial.
– Peak probably noble gases (little effect) followed by
cesium. (134 and 137)
– Take peak and multiply by width
– I found a site boundary dose of about 2 Rems (0.02 Sv)
and falling
– My 2011 CAT scan doses totaled 2.4 Rems
– Should I or anyone, be worried?
My Report (for Massachussetts)
After TMI
Only a few isotopes actually matter
A driving force needed to disperse radionuclides
TMI: almost no dispersive force
Chernobyl: initial explosion plus graphite fire at
4000 ° F (2200 ° C)
Fukushima only hydrogen explosion and fuel at
1900 ° F (1050 ° C)
Evaporation
Temperature
184°C
671°
C
990°C
1750°C
Products of Fission
Gases
(1) Noble Gases (Kryton,xenon)
(2) Iodine goes to thyroid: leukemia, thyroid cancers
(Do not drink milk for a month)
Solids
sublimate as temperature goes up
(A) Cesium 134, 137. do not stay in body
(B) Strontium, transuranics
These only sublimate at higher temperature, not
much even at Chernobyl
Table not broken down by age (MY MISTAKE!)
Rems/man or manRems?
• We need the effect on an individual or the small
group being affected then Rems per man is the
proper description
(emphasized by the late Rosalyn Yalow, Nobel
Laureate who died a couple of months ago)
• Traditionally health physicists assume a linear
dose response and then it is clear that the societal
effect is best expressed in Man Rems or Person
Sievert
Adverse Effects of Evacuation
– Stress can increase cancer rates 5% or more
– Direct loss of life due to lack of facilities
– NO ONE CONSIDERED THESE AT ALL
– These could have been discussed in advance
– Scientists discussed these after TMI and adverse
effects of evacuation were the only casualties!
Chairman Gregory Jaczko
testimony in US Congress
March 17th 2011
“ Recently, the NRC made a recommendation that:
Based on the available information that we have, that for a
comparable situation in the United States, we would
recommend an evacuation to a much larger radius than
has currently been provided in Japan. As a result of this
recommendation, the ambassador in Japan has issued a
statement to American citizens that we believe it is
appropriate to evacuate to a larger distance up to
approximately 50 miles.”
This recommendation was not accompanied by a
justification .
I formally objected within a week but
my objection was not acknowledged by NRC
Jaczko’s recommendation was echoed by
President Obama and
had an immediate deleterious effect
It has not to my knowledge been explained or
withdrawn by Dr Jaczko or the President
Once the President had said something motives
other than public health took precedence.
Sensible discussion became difficult
Media editors would no longer admit letters
and comments from experts
(I was effectively silenced)
Sensible journalists were cowed.
Japanese media amplified it still further.
Apology
I cannot speak for
Dr. Jaczko or President Obama.
But I make a personal apology to all the
Japanese people. I regret that I was unable to
stop these damaging statements
I have requested a formal review by NRC
http://physics.harvard.edu/~wilson/Comment by Richard Wilson.doc
What was the effect
on the way to Tokyo?
• I looked at the data published by MEXT
(Ministry of Education,Culture,Sports,Science
& Technology in Japan)
and by KEK (High Energy Accelerator
Research Organization)
• The first slide is from MEXT, the second is
the same BUT different axes. It does not
look so bad!
What about Ibaraki? (on way to Tokyo)
Cumulative 0.4Sv (40 mRem)
(1/10 of yearly background)
It looks different with different scale.
Dose the same but seems negligible
At KEK the numbers are still smaller.
My friends at KEK understand radiation.
Subsequent study (IAEA, INPO, TEPCO, etc)
confirms:
•No one got Acute Radiation Syndrome
•Highest exposure in a worker: 30 Rems
NOT 400 Rems!
•If there are cancers the probability of causation
(POC) will be less than 50% in all but a few cases.
Threshold or linearity?
It is important that you understand the argument
for low dose linearity
BUT when dose is low it should not matter
But do not in public argue with your supporters
who reject the threshold arguments
Data only exist at levels
much higher than background
Alternate Dose-Response Models
Data above region of interest
Cancer Over Background
Excess Dose
Low dose Linearity
is a General Argument
• Probability of dying in a car accident in Harvard
Square is roughly proportional to the number of
cars!
• If the medical outcomes is not distinguishable
from an outcome occurring naturally then the
argument applies
• Inherent in the multistage theory of cancer
• Lung effects caused by air pollution
Biological Effects of Ionizing Radiation
(BEIR) report assuming low dose linearity
US National Academy of Sciences
Not broken down by age
BUT Deposition to NW of plant highest from
Tuesday/Wednesday releases
Sv
0.225
0.23
0.1
0.103
0.1
0.101
0.01
0.001
0.001
What should a decision maker have done
(my personal opinion)?
• Order an immediate evacuation for many km ?
• Make it easy for any VOLUNTARY evacuation
– to avoid panic as happened after Katrina
NO
YES
• Do simple steps to reduce exposure to fall out
– including measurement
YES
• ORDER all out clean up for years
NO
• Facilitate individual towns and people in voluntary steps
• Richard Wilson paper in DOSE_RESPONSE (2012):
YES
“Evacuation Criteria After a Nuclear Accident:
A Personal Perspective”
Comparison with other disasters
10,000,000 per year
5,000 upwards
• Even under the usual conservative model of
low dose linearity
• Natural background every year produces
2000 the number of cancers in the world as
Fukushima did in a lifetime!
• Which should the world worry about more?
Public Panic may have
stopped nuclear power for 50 years
Nuclear Engineers only
emphasize safety improvements
Radiation experts and
basic scientists are silent
They allow nonsense to dominate the discussion
Cost is determined by virulent public opposition
Many Nuclear Power Programs are Cancelled
Yet problem is important for terrorism:
(1) Take 1000 Ci medical source
(2) Add a few pounds TNT
(3) Explode in Wall Street
EFFECT:
(A) Less than 10 people die
(situation in Brazil)
(B) 20 square miles out of action using
existing conservative regulations
THIS MAKES ACTION ATTRACTIVE
FOR A TERRORIST
Even More Important
 What do you do if someone explodes a
nuclear bomb in Osaka Harbor?
 Run away as fast as you can?
NO
 Take shelter for 24 hours till radioactivity
does and listen to which way the wind is
blowing?
 Then if you are in the plume run fast,
but which way? Away from explosion?
 Sideways away from plume?
YES
YES
NO
Thank you for listening