ML18003A510
| ML18003A510 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 03/30/1979 |
| From: | Mcduffie M CAROLINA POWER & LIGHT CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7904060250 | |
| Download: ML18003A510 (17) | |
Text
REGULATO Y
INFORMATION DISTRIBUTION STEM (RIDS)
ACCESSXOS NBRi7904060250 DOC ~ DATE'- 79/03/30 NOTARIZED:
NO FACIAL>>50~000 SHEARON HARRIS NUCLEAR POWER PLANTg UNIT 1i CAROIINA 50~401 SHEARON HARRlS NUCLEAR POWER PLANTg UNIT 2g CAROLINA 50 002 SHEARON HARRlS NUCI EAR POWER PLANTg UNIT Bg CAROI INA AUTH'AMK AUTHOR AFFII IATION MCDUFFIfg M ~ A ~
CAROLINA POWER 5 LIGHT CO ~
RECIP ~ NAMf RECIPIENT AFFILlATION DKNTONEH ~ R>>
OFFICE OF NUCLFAR REACTOR REGULATION
SUBJECT:
FORWARDS REPT OF GEOLOGIC FEATURES IN MAIN DAM CORE TRENCH'ONCLUDES THKST GEOI.OGIC FKATURES CANNOT BE'APABLE FAULTS AS DEFINED IN APP A
TO 10CFR100
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'EZDC/DSB Authorized Signature
Carolina Power 8 Light Company March 30, 1979 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Washington, D. C.
20555 SHEARON HARRIS NUCLEAR POWER PLANT, UNIT NOS. 1, 2, 3, AND 4 DOCKET NOS. 50-400, 50-401, 50-402, AND 50-403 GEOLOGIC FEATURES IN THE MAIN DAM CORE TRENCH
Dear Mr. Denton:
The attached report provides a final geologic description of Faults A2, A4, A5, E, F, F2, and Fault Group G located in the Shearon Harris Nuclear Power Plant's (SHNPP) main dam core trench between Stations 1+90 and 2+90.
The existence of these geologic features has been previously reported to your staff by either telephone or discussions with your staff representa-tives during site visits.
As discussed in the report, these geologic features occurred prior to the deformation-mineralization process of 225 million years ago.
Therefore, Carolina Power
& Light Company concludes that these geologic features cannot be capable faults as defined in Appendix A to 10CFR100.
Yours very truly, Qa +
M. A. McDuffie Senior Vice President Engineering 6 Construction RGB/mf Attachment cc:
Mr. J.
C. Bryant 7 90406 025o
~tt ~eye':ev ate Street
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9 C, 2"~C2
SHEARON HARRIS NUCLEAR POWER PLANT UNIT NO.S 1, 2, 3, and 4 GEOLOGIC REPORT ON FAULTS A2, A4, A5, E, F, F2, and G
AT THE MAIN DAM The following is a report on small Faults A2, A4, A5, E, F, F2, and G
which are all exposed in the core trench between Stations 2+90 and 1+90.
Location of the core trench is shown on Figure 1.
These seven faults are shown on the geologic map, Figure 2, at a scale of 1 inch to 10 feet.
Also see photos.
Numbered features are described on. the key, Figure 2A.
Faults A4, E, F, and G were first shown to NRC geologists on January, 30, 1979.
Fault A2 was inspected in December and Fault F2 and A5 were found after the January 30th inspection.
Table 1 "Foundation Features and Faults Discovered to Date" has been revised to show the current status of fault reports for the main dam.
FAULT A2 Fault A was first described in our report of January 24, 1979, as follows:
"Fault 2 as shown on Photo 3 and Figure 2 has an orientation of N 34 E
81 SE.
'@is fault shows right-lateral strike separation of one to four inches (No. 38, 39, 40).
Fault A2 is located en echelon right to Fault A and is filled in places with a black mineral(s) very similar to that noted for Fault A.
The amount of strike separation along Fault A2 is decreasing to the northeast where the fault terminates at Station 3+02.
To the south-west, Fault A2 has yet to be traced as cleaning has not progressed above Station 2+90".
Fault A2 has now been exposed to where it terminates in the southeast wall at Station 2+70.
The additional exposure supports the previous evidence for the noncapability of the fault.
FAULT A4 Fault A4 has a strike of N39 E, a vertical dip, and shows a maximum of 1.25 inches of right-lateral strike separation of a small quartz feldspar veinlet (No. 32).
The fault extends for approximately 4 feet from Station 2+89 to 2+85 22 feet downstream of the centerline.
Fault A4 is located en enchelon right to Fault A and A2 and has iron stains and mineralization in the fault plane as do Faults A and A2.
A small epidote vein, too small to show on the map, crosses Fault A4 near Station 2+85 with no offset.
FAULT A5 Fault A5 has an orientation of N51E 85oSE and shows 4.5 to 5 inches of right-lateral strike separation of two small pegmatite veins (No.
27 and 28).
Fault A5 extends from Station 2+20 to 2+40 about six feet downstream from
\\
the centerline.
Near Station 2+23 the pegmatite vein has been smeared along the fault plane.
At Station 2+34 Fault A5 passes through a small pegmatite vein with no offset.
To the southwest, near Station 2+20, Fault Ad terminates at a metamorphosed mafia dike which is older than Fault A.
In places, the fault is filled with a thin layer of brownish-black neralization.
FAULT E Fault E has an orientation of N42 E 80 SE and shows 1.25 to 0.5 inches of left-lateral strike separation of two small pegmatite veins (No.
33 and 34).
'Fault E extends from Station 2+53 to 2+42 and is about 20 feet downstream from the.centerline.,
Iron stains and a thin layer of fine-grained black minerali-zation occur in the fault.
The nature of this mineralization and the orientation of Fault E are very similar to the A-type faults previously des-
- cribed, except that the sense of separation is left lateral for Fault E.
This fault crosses a third pegmatite vein at Station 2+43 with no offset.
FAULT F Fault F has an orientation of N64 E 77 NW, extends from Station 2+11 to beyond 1+90 and is about 22 feet. downstream from the centerline.
The fault is not open and appears to be partially healed as it passes beyond Station 1+90.
Maximum displacement is 2.5 inches of left-lateral strike separation.
Two small pegmatite veins (Nos.
4 and 6) and two epidote veinlets (Nos.
2 and 8) are offset between Station 1+95 and 2+05.
However, the amount of strike separation is decreasing in both directions along Fault F.
An epidote veinlet (No. 9) and a quartz veinlet (No. 7) cross Fault F with no offset.
Therefore, Fault F is definitely older than the quartz mineralization and some of the epidote mineralization.
FAULT F2 Fault F
is oriented N64 E 80 NW and extends from Station 1+97 to 2+20 2
about 7 feet upstream from the centerline.
This fault has 6.5 inches of apparent left-lateral strike separation of a fine-grained mafic vein (No.
16).
Some of the observed separation may not be real as the vein width varies from 1 to 4 inches.
Two thin vertically dipping pegmatite veinlets cross Fault F2 with no offset.
The absence of any offset of these vertically dipping peg-matite veinlets also suggests that the amount of true separation is considerably less than 6.5 inches.
The fault terminates at Station 1+97 to the southwest and at a metamorphosed mafic dike near Station 2+20 to the northeast.
FAULT GROUP G
Fault Group G consists of two closely spaced subparallel fractures with orientations of N60 E 85 NW and N61 E 81 NW.
The group extends from Station 2+06 to beyond Station 1+90 and is located about 8 'feet downstream from the centerline.
Fault Group G shows 1.5 to 3.5 inches of right-lateral strike separation of a pegmatite veinlet which has an orientation of N65 W 70 SW
(Nos.14 and
- 15) and 16.5 inches of left-lateral strike separation of.a 4-inch wide pegmatite vein which has a very shallow dip to the northeast.
The geometry of the two pegmatite veins and the N61 E 81 NW fracture of Fault Group G shows that there has been normal movement along this fracture with the northwest block having moved down 6 inches relative to the southeast block.
The N60 E, 85 NW fracture of Fault Group G does not offset the shallow-dipping pegmatite vein near Station 1+88 and is also partially healed beyond Station 1+90.
The N61 E 81 NW fracture of Fault Group G has been filled with biotite and opaque minerals to a thickness ranging up to 2 to 3
inches near Station 2+05.
A thin epidote veinlet crosses the N61 E 81 NW fracture of Fault Group G at Station 2+02 with no offset.
Fault Group G
will be further exposed when cleaning proceeds beyond Station 1+90 in the core trench.
CONCLUSION The small separation along these faults, the short lengths of the faults, the relationship of veins and pods crossing the faults, and/or the relation-ship of the faults to two metamorphosed mafic dikes as well as mineralization in the faults indicate that Faults A2, A4, A5, E, F, F2, and G developed prior to ancient thermal activity.
Attachment B of the CP6L report of October 17, 1978, to the NRC on "Geological Feature at the West Wall of Main Dam Diversion Conduit" documented that the last deformation mineralization process would have occured more than 225 million years ago.
Because the small movement along these seven faults occurred prior to the deformation-minerali-zation, Faults A2, A4, A~, E, F, F2, and G cannot be capable faults as that term is defined in Appendix A to 10 CFR 100.
TABLE 1 MAIN DAM FOUNDATION FEATURES AND FAULTS DISCOVERED TO DATE Feature/Fault Deformational Feature Schistose Zone Location Sp'illway Sta 15+41 Conduit Sta 2+55 Report'o NRC Initial'ritten 12/8/77 12/15/77 9/19/78 10/17/78 NRC Ins ection 12/14/77 9/19/78 Fault A
-Core Trench Sta 3+10 ll/9/78 11/29/78 12/8/78 Fault Group B
Core Trench Sta 3+10 11/16/78 11/29/78 12/8/78 Fault C
Core Trench Sta 3+60 11/16/78 1/24/79 12/8/78 Fault Group D
I
~ Fault A2 Fault A3 Offsets in Spillway Core Trench Sta 3+32 Core Trench Sta 3+00 Core Trench Wall Sta 3+40 Spillway Sta 11+70 Sta 12+02 Sta 12+10 12/1/78 1/24/79 12/8/78 1/24/79 1/19/79 This Report 11/16/78 1/24/79 12/20/78 Pending 12/8/78 12/8/78 1/30/79 12/8/78 1/30/79 1/30/79 Fault A4 Fault E
Fault F
Fault G
Fault F2 Core Trench Sta 2+87 Core Trench Sta 2+45 Core Trench Sta 2+03 Core Trench fata
/+97 Core Trench Sta 2+04 1/26/79 1/26/79 1/30/79 1/30/79 2/2/79 This Report This Report This Report This Report This Report 1/30/79 1/30/79 1/30/79 1/30/79 Pending
TABLE 1
(Continued)
MAIN DAM FOUNDATION FEATURES AND FAULTS DISCOVERED TO DATE Feature/Fault Location Report to NRC Initial Written NRC Ins ection Gneiss Layer 63 Core Trench
& Schistose Zone 82 Sta 3+6O to 2+9O 1/30/79 2/2/79 1/30/79 Fault Ag Core Trench Sta 2+23 2/12/79 This Report Pending
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SOUTHEAST WAI.L 26
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10 SCALE IN FEET 20 THIS DOCUMENT IS DELIVERED IN ACCORDANCE WITH AND IS SUSJECT TO THE PROVISIONS OF SECTION X Of THE CONTRACT 8E1WEEN CARO-LINA POWER 4 UGHT COMPANY AND ESASCO SERVICES INCORPORATED DATED SEPTEMSER I, 1870. AS AMENDED.
lYOTEI SEE FIGURE 2A FOR KEYTO GEOLOGIC SECTION CAROLINAPOWER 8 LIGHTCOMPANY SHEARON HARRIS NUCLEAR POWER PLANT MAINDAM PLAN GEOLOGIC MAPI CORETRENCH STA. 1690 10 2+SO EBASCO SERVICES INCORPORATED SCALE I ILr VED DATE NO. DATE REVISION SY CIL APPROVEO FIGURE 2
FIGURE 2A KEY TO PLAN GEOLOGIC MAP CORE TRENCH STATION 1+90 to 2+90 SCALE 110'.
I 3.
4.
5.
6.
7.
8.
9.
10.
11 12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
24.
25.
27.
28.
29.
30.
31.
32.
33.
34.
35.
1 to 2 inch wide epidote vein.
2.5 inches left.lateral strike separation of epidote vein along Fault F.
Very thin pegmatite vein.
2.5 inches left.lateral strike separation of pegmatite vein along Fault F.
3 inch wide pegmatite vein.
0.5 inch left.lateral strike separation of pegmatite vein along Fault F.
Thin quartz vein crosses Fault F with no offset.
0.5 inch left.lateral strike separation of a thin epidote vein along Fault F.
Thin epidote vein crosses Fault F with no offset.
Micaeous gneiss layer widens to more than one foot. This layer of rock is similar to the homblendemica gneiss but contains more mica than the gneissic rock, Is brown in color, and is moderately weathered and moderately hard. ISee 63 and 64, from Plan Geologic Map of Northwest Side of Core Trench, Sta. 2+90 to 3&0).
Thin, 1 to 4 inches wide, zone showing flow texture along contact of the metamorphased mafic dike and the country rock.
Small epidote vein is exposed on both sides of Fault G which has 24 inches of biotite and opaque minerals fillingthe fault plane at this location.
Thin 0.5 inch pegmatite vein with an orientation of N54 W 70 SE.
1.5 inches right-lateral strike separation of thin pegmatite vein along Fault G.
3.5 inches right lateral strike separation of thin pegmatite vein along Fault G.
6.5 inches of apparent left-lateral strike separation of a fine to medium~rained dark grey mafic vein 3P inches wide along Fault F2.
This vein appears to crosscut two thin pegmatite veins.
Hexagonal quartz crystals growing in the fracture.
Peynatite vein.
Thin quartz. feldspar veinlet.
Ouartz-feldspar-biotite pod.
Large biotite pod with some associated quartz.
In many places biotite is weathered away leaving large voids. Country rock adjacent to the biotite pods is bleached to a dirty white color.
Massive biotite pod which crosses micaeous gneiss layer 63 Ifrom Plan Geologic Map of Northwest Side of Core Trench, Sta. 2+90 to 3+60) and has not been offset.
Very uniformly thin pegmatite veins.
Several millimeters of fine~rained quartz in fracture.
Biotite pod which has been weathered away leaving voids filled in some places with quartz and tourmaline crystals.
Country rock adjacent to biotite pod has been bleached.
Metamorphosed mafic dike which is possibly a metabasalt, is medium to finegrained, very dark grey to black in color, hard and fresh.
Regional foliation is imprinted on the dike rock and is continuous with the foliation in the country rock except near the contact.
4.5 inches right lateral strike separation of pegmatite vein along Fault A5.
5.0 inches right-lateral strike separation of pegmatite vein along Fault A5.
Pegmatite vein crosses Fault A5 with no offset.
Micaeous gneiss layer 63 Ifrom Plan Geologic Map of Northwest Side of Core Trench, Sta. 2+90 to 3+60) terminates.
Thin epidote vein crosses Fault G with no offset.
1.25 inches of rlght4ateral strike separation of a small quartz. feldspar vein along Fault A4.
1.25 inches of left-lateral strike separation of a pegmatite vein along Fault E.
0.5 inches of left-lateral strike separation of a pegmatite vein along Fault E.
Fault A2 terminates in the Southeast Wall.
PHOTO 1
VIKNNKST OF CORE TRENCH FROM STATiON 1+90 TO 2+20 SHMAhNa FAULTSf, G, AND F2 No. SHNPP Main Darn 3fES-l
'2/6/79
PHOTO 2 YIENSOUTHEAST OF CORE TRENCH FROM STATION 2+20 TO 2+30 SI lOWING FAULTA~ MICAEOUS GNEISS LAYER,AND SMALLMAFIC DIKE No. SHNPP Main Dam 3/79-2 2/6/79
PW3TO 3 VIEW EAST OF CORE TRENCH FRQNI STATION 2+30 TO 2+50 SHOWING FAULTE,.MAFIC DIKE,AND MICAEOUS GNEISS LAYER.
No. SHNPP Main Dam 3/79-3 2/6/79
VIEW EAST OF CORE TRENCH FROM STATION 2+50 TO 2+90 SHOWING FAULTSA>ANDA4, MAFICDIKE, BLEACHED BIOTITE POD, AND MICAEOU8 GNEISS LAYER.
No. SHNPP Main Dam 3/79-4