Effective Dose Equivalent (CEDE) - Technical Background
The following two graphs show the commited effective dose equivalent
(CEDE) of the radioactive plume that would be created by an unconfined
plutonium explosion in Los Alamos. The calculation is from Lawrence
Livermore National Laboratory HOTSPOT 8.0 code. HOTSPOT's calculation
gives lower doses than DOE's 1997 calculation (C. M. Steele, T. L. Wald,
and D. I. Chanin, Plutonium Explosive Dispersal
Modeling Using the MACCS2 Computer Code, Department of Energy, Los
Alamos Area Office, 5/1997. Link is to cover page only; obtain
full document from DOE.)
How these doses translate into expected fatalities
is shown in the table below.
| Relationship of CEDE to Latent Cancer
(How individual doses relate to the probability of fatal cancer caused
|If the 50-year Committed
Effective Dose Equivalent
(for nonsmokers) is
|then the probability
of an LCF (per person exposed), i.e. the
(for nonsmokers), is
|and the p(LCF) with long-
term dust resuspension
(for nonsmokers) is
|and the p(LCF) with dust
(for smokers) is
||0.5 (50% chance of fatal cancer)
||0.8 (80% chance of fatal cancer)
||1 (100% chance of fatal
All figures are for male adults outdoors undergoing light exercise. For
example, a person at TA-55/35 would receive a CEDE of 20 rems from the
postulated accident and thus have a 1 % chance of a LCF. Out of
a working population of 1000 persons, roughly 10 would eventually die
from the accident, assuming all were nonsmokers.
In the Los Alamos townsite, CEDEs in the neighborhood of 10 rems could
be expected, resulting in a 0.5% chance of LCF per nonsmoking person;
smokers, on the other hand, who were caught outdoors would be highly likely
to contract a fatal cancer. In the Las Campanas region, CEDEs around
2 rems would lead to a 0.1 % chance of a LCF, or 20% for smokers, not
counting long-term dust resuspension doses, which raise these probabilities
by about 60%. In Santa Fe proper, doses nearly this high would be
experienced. The graph below shows these doses in plan view.
These contours show the lifetime dose commitments delivered by the plutonium
cloud to each non-smoking individual who breathes it, under standard assumptions.
A 1.26 rem prompt dose commitment (middle contour) will deliver about
2.0 rem in the long run, due to resuspension of dust (Fetter and von Hippel,
1990, "The Hazard from Plutonium Dispersal by Nuclear-Warhead Accidents,"
Science and Global Security, Vol.2, p. 30). There will be about
0.001 cancer deaths for each 2 rem committed to the population by plutonium
(DOE, 1995, DARHT Final EIS, Vol 1, p. H-9). To get total expected
cancer deaths, multiply lifetime dose in rems per individual by the number
of individuals exposed, then divide by 2000 rems/death.
These HOTSPOT results generally agree with DOE's results in the DARHT
FEIS as well as those of Fetter and von Hippel, and were very favorably
tested by Livermore Lab against experimental data from the Nevada Test
The likelihood that smokers (who comprise 23 % of population, according
to the 1992 Statistical Abstract of the U.S.) will contract fatal cancers
from a given plutonium dose is approximately 200 times more than for nonsmokers
(Gofman, 1981, Radiation and Human Health, p. 488). The following
graph shows the ground contamination (fallout) expected from the cloud.
The EPA action level for residential areas is 0.1 micro Ci/m2 (EPA, 1990, Transuranium Elements, Vol. 2, Technical Basis for Remedial
Actions, p. 5-12, EPA 520/1-90-0 16). Real properties which received
greater deposition than this could have impaired utility and value for
residential purposes. Some impact on the region as a tourism, residential,
and business destination could occur. Areas of greatest deposition
might have to be abandoned for residential purposes, and cleanup of highly
contaminated zones for even industrial and R&D purposes would be difficult,
dangerous, uncertain, and expensive.
It is approximately 3.5 km from the DARHT site to heavily-occupied Lab
areas, about 5.4 km to the Los Alamos town site, and about 7.8 km to White
Rock. It is about 36 km (or 22 miles) from DARHT to the Santa Fe
plaza, with Las Campanas, etc. occupying an intermediate location.