ML20209D443
| ML20209D443 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/17/1984 |
| From: | Brocoum S Office of Nuclear Reactor Regulation |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20150F500 | List:
|
| References | |
| FOIA-86-391 NUDOCS 8410240355 | |
| Download: ML20209D443 (5) | |
Text
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DCT 171l184 MEMORANDUM FOR:
George Knighton, Chief Licensing Branch No. 3 Division of Licensing FROM:
Stephan Brocoum, Acting Chief Geosciences Branch Division of Engineering
SUBJECT:
SUMMARY
OF OCTOBER 4, 1984 MEETING WITH PG&E REGARDING ELEMENTS 1 & 2 0F THE DIABLO CANYON LICENSE SEISMIC CONDITION A technical summary of the October 4 meeting among PG&E, its geological consultants, the NRC and its advisors concerning the geology and tectonics of the Diablo Canyon site is attached for your use in preparing the official minutes of the meeting. Enclosures 1, 2 and 3 are an attendance list and copies of the viewgraphs presented by PG&E.
Stephan rocoum, Acting Chief Geosciences Branch Division of Engineering
Enclosures:
As stated cc: w/o enclosures J. Knight S. Brocoum L. Reiter H. Scherling R. Rothman R. McMullen
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MEETING AMONG PG&E, AND ITS GE0 LOGICAL CONSULTANTS THE NRC AND ITS ADVISORS REGARDING THE DIABLO CANYON LICENSE SEISMIC CONDITION The first of four meetings was held among Pacific Gas and Electric Company (PG&E) and its geological consultants and the Nuclear Regulatory Comission and its advisors, the U. S. Geological Survey (USGS) and Dr. D.
B. Slemons to discuss investigation programs to address the Diablo Canyon Operating Seismic License Condition. The meeting took place on October 4, 1984, in Bethesda and the subject was Element 1, Geology and Tectonics, of the License Condition. A list of attendees is attached as Enclosure 1.
Following introductory remarks by Mr. D. Brand, Vice President for Engineering, PG&E, and Steve Brocoum, Leader of the Geology Section, of Geosciences Branch, NRC, Mr. W. White described the PG&E organization that will carry out the requirements of the License Condition. Enclosure 2 contains diagrams that illustrate the chain of comand and division of labor in a preliminary and general way.
The NRC presented a brief description of its parallel program in the area of geology and tectonics. The Geosciences Branch is presently engaged in preparing contracts for the USGS and Dr. Slemons. Contract preparation and agreement among the parties are expected to be completed by January,1, 1984.
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_2-Dr. D. Hamilton, geological consultant for PG&E described the proposed l
investigation program. The geologic program consists of five tasks:
(1) Identification and evaluation of post-1978 site and regional data; (2) evaluation of tectonic model; (3) review of seismic source parameters; (4) review of source to site geology and transmission path characteristics; (5) and support of parallel activities in related areas of the long-term seismic program. Details of each task are presented on Enclosure 3.
During Dr. Hamilton's presentation, Mr. R. Willingham, a geophysicist with Ogle Petroleum Company, described the types of seismic reflection and well data that are available in the offshore from Diablo Canyon.
NRC and its advisors held a caucus after the PG&E presentation. As a result of that caucus, Dr. S. Brocoum, Geology Section Leader, presented the following comments to PG&E.
It is the Geosciences Branch's and its advisors' opinion that:
(1) PG&E has made a serious effort in its planning to respond to the licensing condition and the NRC team is impressed by the quality of the program; (2) PG8E has performed well in identifying and defining the data bases and in preparing a program to utilize these data bases; (3) PG&E's use of panels assembled to plan and monitor the work is a good idea; e
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3-(4) more emphasis should be placed on the way in which PG&E will resolve the issue of gaining an understanding of the tectonic framework of the part of California in which the site is located including the characteristics of the transition from a dominantly thrust tectonic regime south of the site to a dominantly strike-slip regime north of the site; (5)
PG&E needs to discuss how it will use the data described in the presentation to develop an understanding of the tectonics in the site area and onshore northeast of the site; i
(6)
PG&E needs to determine how it will identify and define or show'the e
absence of thrust faulting directly beneath the site and what data will be used to accomplish this; (7) the presentation emphasized the kinds of data that will be used. An
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additional step is necessary, that is, to correlate the kinds of data to be obtained with the outstanding issues and show how they are to be resolved with the data; I
(8) an understanding of the offshore faults may come from studying the onshore faults; (9) the importance of studying associated folds to learn about faults that do not break the sea floor or ground surface should be strongly i
emphasized; (10) available techniques, such as borehole 3 dimensional logs, bore hole breakouts, etc. should be used to help estimate the state of stress; l
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. (11) segmentation of the faults in the region as it relates to earthquake j.
potential should be evaluated; (12) the three mile interval immediately offshore is notably lacking in data. Effort should be made to obtain data in this area; and (13) PG8E's program is its responsibility, and as such it should not rely on the staff or others to identify every area that requires study.
It was decided that the second meeting (earthquake and ground motion) should be held on November 15 and 16,1984. The third meeting, concerning PRA, will be convened during the second or third week of Decc=ber,1984.
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