ML20054E828
| ML20054E828 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 06/01/1982 |
| From: | Youngblood B Office of Nuclear Reactor Regulation |
| To: | Delgeorge L COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8206140303 | |
| Download: ML20054E828 (6) | |
Text
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DIST:
Document' Control: (STN 50-454/455);
NRC PDR L PDR JUN 1 1982 NSIC TERA LB#1 Rdg.
Docket flos.: STil 50-454 MRushbrook and STil 50-455 SChesnut Attorney, OELD OIE Mr. Louis 0. DelGeorge ACRS(16)
Director of fluclear Licensing Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690
Dear Mr. DelGeorge:
Subject:
Byron Essential Service Water Pipeline Foundation Based on the results of several meetings with your staff and recent field observations, the staff has detennined that additional subsurface information is needed in order to determine the adequacy of the foundation support for the essential service water pipeline at the Byron Station. The specific nature of the information needed is described in Enclosure 1.
The criteria which will be used by the staff to evaluate the results is described in.
Pl': se review the enclosures and provide your schedule for responding to this request within three weeks of receipt of this letter. Contact the project manager, Stephen Chesnut if you have questions with regard to this request.
l Sjnppf&iv ignea by:
s B. J. Youngblood.,
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B. J. Youngblood, Chief l
Licensing Branch No. 1 Division of Licensing
Enclosures:
As stated cc w/encls.: See next page 8206140303 820601 PDR ADOCK 05000454 A
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- Mr. Louis 0. De1 George Driector of Nuclear Licensing Commonwealth Edison Company Post Office Box 767 Chicago, Illinois 60690 cc: Mr. William Kortier Mr. James G. Keppler Atomic Power Distribution U. S. NRC, Region III Uestinghouse Electric Corporation 799 Roosevelt Road Post Office Box 355 Glen Ellyn, Illinois 60137 Pittsburgh, Pennsylavania 15230 Paul M. Murphy, Esq.
Isham, Lincoln & Beale One First National Plaza 42nd Floor Chicago, Illinois 60603
'Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, Illinois 61107 Ms. Bridget Little Rorem Appleseed Coordinator 117 North Linden Street Essex, Illinois 60935 Dr. Bruce von Zellen Department of Biological Sciences Northern Illinois University DeKalb, Illinois 61107 Mr. Edward R. Crass Nuclear Safeguards and Licensing Division Sargent & Lundy Engineers 55 East Monroe Street Chicago, Illinois 60603.
Myron Cherry, Esq.
Cherry & Flynn Suite 3700 Three First National Plaza l
Chicago, Illinois 60602 Mr. William Fourney V. S. Nuclear Regulatory Commission Byron / Resident Inspectors Office 4448 German Church Road Byron, Illinois 61010 Ms. Diane Chavez 602 Oak Street, Apt. #4 Rockford, Illinois 61108
ENCLOSURE 1
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STAFF REQUIREMENTS For the above reasons, the staff requires additional information to confirm that the foundation design for the pipeline is acceptable.
Specifically, the staff requires the following:
(1) At least four slanted borings should be drilled at the site, two borings at area 9 and two borings at area 11. These borings should be drilled at an angle about 45* from the vertical with a penetration I
of about 80 ft into rock. The advancement of the borings should be in a direction that will directly cross the two major joint trends in L
area 9 and 11. A double-tube core barrel with bottom discharge bit should be used for core recovery. All information pertinent to core recovery (bit rotation speed, drilling rod pressure, rate of advancement and bit condition) should be recorded.
If, during the drilling operation, dropping of rods in excess of 1 ft in 5 ft of penetration and coincident loss of significant drilling fluid occur, in situ observation methods or additional slanted borings should be used to determine the nature, geometry, and spacing of these anomalies.
When joints are encountered, the infill materials should be sampled, I
and their source identified.
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,a e-ry-g r-m (2? The applicant should establish the maximum unsupported span for the as-built pipeline and its limiting differential settlement values.
(3)
If the above slanted borings in area 9 and 11 find that the joint conditions might adversely affect the support of the pipeline, as determined in accordance to staff's acceptance criteria (Enclosure 2),
additional slanted borings should be drilled at area 12 to determine the rock and the joint conditions there.
(4) At Area'll, two soil borings, about 50' apart, should be drilled in the vicinity of Sta. 48 + 20N, where differential settlement is of concern, to secure undisturbed soil samples from the organic clayey silt layer and the underlying silty clay layer. These undisturbed samples should be subjected to laboratory testing to determine their compression and consolidation properties.
(5) At Area 12, between Sta. 40 + 50N and Sta. 45 + 20N, where settlements are of concern, soil borings shoull be drilled at about 50 foot spacing.
Two of these borings should use continuous sampling technique to verify the subsurface profile. All the other borings (about 6) should use the Standard Penetration Test Procedure (ASTM D-1586).
Undisturbed samples should be obtained from the organic silt and silty clay layers for laboratory consolidation tests. The compacted fill above the pipeline needs no sampling.
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(6) The differential settlements along the uncased pipeline should be determined and their effects on the pipeline should be evaluated
+
from the information obtained from the exploration and testing program outlined in (3) through (5).
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4 Byron Criteria for Reviewing Exoloration Results; Purposes of the Boring Program:
1.
To confirm that design foundation support conditions along the pipeline will be maintained (i.e., the induced pipe stresses are within code limits).
2.
To establish the amount and effect of differential settlement on the pipeline (i.e., the induced pipe stresses are within code limits).
Acceptance Criteria:
1.
Staff will consider the foundation support acceptable if the results of the slant borings show the following:
a.
An open or partially filled joint with 4.5' max. width, b.
Filled joints, c.
The percentage of open joints in a 50' rock caring
< 20% in the upper s
40' of rock.
d.
The induced pipe stresses due to loss of foundation support or differential settlement are conservatively shown to be within code limits.
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