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SUBJECT:
CIBCSSTANCES RMBARDIN CEAMBES 15 WORDING OF W. 8. GEOEA01 CAL SMTET BRAFT REF0EfB ON CORRAL CA'!N05 SITE - DREW FIARSON COLSE OF NOVEMBER 14. IM5 In meeordameo with your rosysset at the meeting en November 15. I em attasking a summeary stataamat prepared by my staff and staff soummel dealing with the esvelopomet of the two U. S. Geological Survey reporta skish semansated en the probability of surfesa femiting at the Malibu site.
(Signed) ELP Marold L. Prise Direeter of Segulation Attasimments suesery Statenmat se General Manager General Counsel Seeretary (2) bec:
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CIRCUMSTANCES REGARDING CHANGES IN WORDING OF U. S. GEOLOGICAL SURVEY DRAFT REPORTS ON CORRAL CANYON SITE - DREW PEARSON COLUlti 0F NOVEMBER 14, 1965 In December 1963 shortly af ter receipt of an application from the City of Los Angeles for construction and operation of a pressurired water reactor to be located at a site in Corral Canyon, California, a report on the geological l
conditions at the proposed site by the U. S. Geological Survey was requested by the AEC.
In the course of the field investigation conducted by members of
.he Geological Survey, several meetings were held with the regulatory staff in order to keep the staf f informed of the results of the work as it progressed.
As the staff safety evaluation Approached completion, the Geological Survey prepared a draft of its report.
In accordance with the Memorandum of Under-standing between the Department of Interior and the AEC, the draf t report was shown to the AEC for review and corment.
Af ter review of the draf t report, a meting was held between the AEC staf f and tne Geological Survey staff to discuss the report.
The regulatory staf f's understanding of the Survey's opinion that the j
probability of permnent ground displacement due to faulting at Corral Canyon is much lower than that at Bodega Head, which had been previously reported on by the Geological Survey, was discussed and confirmed at this meeting held in November 1964 However, the draf t report on Corral Canyon by the Survey stated that "the probability of permnent ground displacement by faulting in the Corral Canyon site in the next 50 years is very low", while the Survey report on Bodega stated that the probability of a 2-3 foot displacement is
" lower than low but still a possibility". Because the similarity between these two qualitative statements could lead to an erroneous conclusion that the Survey believed that the probability of future faulting at these two sites was comparable the AEC staf f suggested' to
- Survey staf f that dif ferent words than "very low" be used in describing the probability of future f aulting at Corral Canyon. As a result of these discussions, the U. S. Geological Survey chose to replace the words "very low" with " negligible" in the final version of its December 1964 report on the geology of the Corral Canyon site. This report was made public when received.
Subsequent to publication of the December 1964 report, additional excavations were undertaken at the proposed Corral Canyon site at the request of the Atomic Safety and Licensing Board. Another draf t U. S. Geological Survey report was prepared for review by the AEC staf f.
This report included the results of the additional investigations and also superseded the previous Survey report 9 concerning the Corral Canyon site.
It concluded that the probability of future ground displacement at Corral Canyon is "very low".
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In subsequent discussions between the AEC staff and the Survey staff held in July 1965 concerning the draf t of this later report, members of the Survey stated that while there had been no change in the Survey's judgment concerning the probability of future faulting in Corral Canyon, the Survey had been criticized by others in the geological fraternity for using _the word " negligible" in its December 1964 report.
The basis of the criticism -
was that negligible could be interpreted to mean that the Geological Survey was recommending to the AEC EMt the probability of future faulting at Corral Canyon be neglected, and the 1.1rvey did not wish to imply that it was making such a risk judgment. Although the AEC staff informed the Survey staff that it was likely that the reason for this second change in wording would be misunderstood, the U. S. Geological Survey report on the geology of Corral Canyon dated July 1965 stated that:
"the probability of permanent displacement of the ground surf ace by faulting at Corral Canyon during the next 50 years is very low (this same very low probability was described in the U.- S.
Geological Survey report of 1964 as negligible, which was used there in the sense of very low).
This assessment implies no judgment of public risk; it is not intended as a judgment of the
- consequences of surf ace f aulting in any particular utilization of the Corral Canyon site."
The substance of the foregoing is set forth in detail in the record of the Malibu proceeding. The circumstances concerning the changing of the words "very low" to " negligible" in the draf t of the December 1964 report while it was still in draf t form v5re the subject of extensive cross examinatica of Geological Survey and AEC g.aff witnesses by the attorney for the intervenors.
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