Enclosure

PN.

Department of Energy

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Nevada Operations Office
PO. Box 14100

Las Vegas, NV 89114

42

410126

NOV 15 1979

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L. JoeDeal, HQ (EV-123)

. W. Wachholz
PPvit ice of Environment, HQ (EV-212)
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“TRANSURANICS DATA, ENEWETAK

Over the past several weeks, NV (ERSP) has been evaluating a systematic

error in the in situ measurement of Americium at Enewetak. This error
derives from the improper use of a soil composition which is not representative of the actual. In calculating the attenuation of 60 KEV

energy, the error is significant (in the range of 20-25%).

Before

introducing a wholesale correction in the Enewetak transuranics data
base, ERSP is evaluating other uncertainties, both systematic and
random. This may require a modest amount of additional field work.
Assuming that the current 20-25% (low) estimate is verified, all Imp
transuranics numbers will require adjustment. At first look, it
appears that this will place the certification of the following islands
technically in question: Irene, Janet, Kate, Mary, Olive, Sally. On
Janet (Engebi) for example, a total of twelve quarter hectare-sized

areas Cannot now be certified to be below the 40 pCi/gm residential
standard.

The highest average reading in any such quarter hectare will

be somewhere between 40 and 50 pCi/gm.

The total affected area (that

which may exceed the standard) will be approximately 2.5% of the total

island area; the island average, however, will remain well below

25 pCi/gm. This reflects the conservatism which has been built into
ERSP application of the 40-80-160 standards.
As it turns out, the technicality of island-by-island certification
remains ambiguous enough to accommodate even the current situation.
This is because the terms "Residential", “Agricultural” and "Food
Gathering", recommended for adoption by the Bair Committee have not
been precisely defined. I drafted a definition paper (copy enclosed)

which was telecopied to Tom McCraw on Jan 30, 1978.

I later (June 12,

1979) telecopied it to you*for comment and/or staffing for approval.
It took the form of a "strawman" of a DOE (Liverman) memo to me and to
DOI and DNA. Since that strawman has not been acted upon, our certification document remains ambiguous in that it refers in Par III to the
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BEST COPY AVAILABLE”

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