ML19320C516
| ML19320C516 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 07/02/1980 |
| From: | Lefevre H Office of Nuclear Reactor Regulation |
| To: | Rolonda Jackson Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19320C517 | List: |
| References | |
| NUDOCS 8007170313 | |
| Download: ML19320C516 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION W.. E WASHINGTON. D. C. 20555
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JUL 0 21980 MEMORANDUM FOR:
Robert E. Jackson, Chief Geosciences Branch, DE THRU:
RichArdMcMuller., Acting L ~cer
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Geology Section Geosciences Branch, DE FROM:
Harold Lefevre, Geologist Geology Section Geosciences Branch, DE
SUBJECT:
GEOLOGIC FEATURES IN THE FLOOR OF THE ULTIMATE HEAT SINK - WOLF CREEK GENERATING STATION, UNIT 1 (STN 50-482)
On Friday morning, April 25, 1980, David F. Fenster, Dames and Moore Project Geologist for the Wolf Creek Generating Station, notified Harold Lefevre (NRC staff geologist, Wolf Creek), that a geologic feature (possible " pop-up") was observed on April 24 in the rock excavation comprising the floor of the Ultimate Heat. Sink. The feature (1) occurred overnight, (2) involves theUpperPennsylvanianPlattsmouthlimestone,(3)issinuous,f4)approximately 100 ft. long discontinuously, and (5) strikes approximately N10 W with offsets ranging from 1/2" to 2."
The above information is preliminary. Mr. Fenster will visit the site over the weekend, conduct field investigations the following week,.and promptly notify the NRC of his findings. As on previous occasions involving geologic matters at the Wolf Creek site, Mr. Frank Wilson, Chief of the Environmental Geology Section of the Kansas Geological Survey, has been contacted by Dames and Moore and will make a site visit en Monday, April 28.
Mr. Wilson has visited the Wolf Creek site many times and is considered by the NRC staff to be well qualified to comment upcn geologic conditions observed there.
Discussion with David Fenster of Dames and Moore At approximately 4 p.m. Monday April 28, 1980, David Fenster contacted H. Lefevre (NRC staff) regarding his recent observations and investigations of the feature at the Wolf Creek Ultimate Heat Sink area:
1.
Fieldmappingindicatednotone,buttwo,disturbedor" pop-up"aregs separated by approximately 100 ft. Both features trend roughly N10 W with the northernmost " pop-up" about 240 ft, long and the southernmost around 70 ft.
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. JUL 0 :: 1980 2.
Both features are discontinuous and die out laterally to the northwest and to the sectheast.
3.
The underlying strata are undisturbed.
4.
No vertical. movement has been detected since the features were first observed (April 24).
5.
The cause of the disturbance is non-tectonic, most likely the result of the rock expansion due to temperature differential.
In order to better describe and illustrate the " pop-up" Mr. Fenster will transmit several photos and field maps as soon as they become available.
(This information was transmitted to the NRC by letter of May 2).
Discussion with Frank Wilson of the Kansas Geological Survey Frank Wilson was phoned by H. Lefevre on Tuesday morning, April 29, 1980 regarding his April 28 examination of the Wolf Creek Ultimate Heat Sink features. Mr. Wilson indicated that the " pop-ups" in the two areas are most likely the result of thermal effects (rapid heating of near-surface shales and limestones following long-term inundation) - not residual stress or other tectonic reasons. Mr. Wilson will prepare a report describing his site observations and conclusions and forward this to tha NRC.
(Mr. Wilson's June 2, 1980 memorandum to the NRC is appended to this report). Mr. C. Oberg of NRC Region IV (Arlington, Texas) was informed on May 2, 1980 regarding F. Wilson's observations and conclusions.
Conclusions Based upon our evaluation of the data presented by Kansas Gas and Electric's geologic consultant and the conclusions expressed by the Kansas Geological Survey, we conclude that the " pop-ups" mapped in the floor of the Ultimate Heat Sink are non-tectonic and pose no hazard to the integrity of the Wolf Creek safety-related structures. Photo-documentaticn and field examination demonstrate that the features are surficial (limited to the upper 0.5 in to 3.0 in) " pop-ups" confined to relatively small areas (70 ft and 240 ft long) of the Ultimate Heat Sink. The " pop-ups" were most likely caused by differential thermal expansion.
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Harold E. Lefevre, Geologist Geology Section Geosciences Branch, DE
Attachment:
As stated cc: See next page
3-JUL o 2 1980 J
cc: w/ attachment D. Eisenhut R. Tedesco J. Youngblood R. Stark J. Knight R. McMullen H. Lefevre J. Greeves E. O'Donnell F. Wilson, Kansas Geol. Survey S. Lewis, ELD R. G. Ryan C. Oberg, Region IV POR Local POR ACRS (17) i i
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