ML20024D243
| ML20024D243 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/26/1983 |
| From: | Schroeder C COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| REF-SSINS-6820, REF-SSINS-SSINS-6 7034N, IEB-80-11, NUDOCS 8308030369 | |
| Download: ML20024D243 (4) | |
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Commonwealth ECson s
) one First Nationit Pitza Chicago. Ilknois l
J Address Reply to: Post Office Box 767
(\\
/ Chicago, Illinois 60690 July 26, 1983 Mr. James G. Keppler, Regional Administrator
- Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 Suoject:
LaSalle County Station Units 1 and 2 Revision to Response to NRC I.E.
Bulletin 80-11 NRC Docket Nos. 50-373 and 50-374 References (a):
I.E.
(b):
C.
W.
Schroeder letter to R. D. Walker dated February 24, 1983.
(c):
C.
W.
Schroeder letter to J. G. Keppler dated September 30, 1982.
(d):
I.E.
Inspection ReDort 50-373/82-43 and 50-374/82-11, dated January 7, 1983.
Dear Mr. Keppler:
Referer"e (b) responded to Reference (a) regarding LaSalle County Station Unit 1.
Following allegations regarding masonry walls at LaSalle County Station, Commonwealth Edison Company submitted Reference (c).
The NRC's review of these allegations and of Reference (c) are contained in Reference (d).
Reference (d), Section 9.d, Further Review of the Licensee's Response to Bulletin 80-11, concluded:
"On October 4, 1983, the licensee submitted the attached evaluation for the masonry walls design for LaSalle based on the vaids observed in these walls.
The methodology of the analysis was reviewed and found acceptable.
The licensee will formally submit a revised response to I.E.Bulletin 80-11 which will include their consideration of voids in the masonry walls."
Enclosed please find a revised response to Section 3.2.b.(ii) of Reference (b).
This revised response section is submitted to fulfill the above quoted commitment from Reference (d).
Commonwealth Edison is currently preparing a full revision of Reference (b) to fully address Units 1 and 2.
It is currently expected that this full revision will be submitted by approximately August 15, 1983.
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J. G. Keppler July 26, 1983 To the best of my knowledge and belief the statements contained herein and in the enclosure are true and correct.
In some respects these statements are not based on my personal knowledge but upon information furnished by other Commonwealth Edison and contractor employees.
Such information has been reviewed in accordance with Company practice and I believe it to be reliable.
If there are any further questions in this matter, please contact this office.
Very truly yours, WW,han C. W. Schroeder Nuclear Licensing Administrator 1m Enclosure cc:
R. D. Walker - NRC Region III NRC Resident Inspector - LSCS US NRC Document Control Desk Washington, D.C.
20555 7034N
- a Rbvised July 25, 1983 REVISION TO FINAL REPORT IN RESPONSE TO t
NRC IE BULLETIN 80-11 Masonry Wall Design for LaSalle County, Unit 1 e'
Commonwealth Edison Company February 10, 1983 3.2.b (ii)
Describe the construction practices employed in the construction of these walls, and, in particular, their adequ other weakn,acy in preventing significant voids or esses in any mortar, grout, or concrete fill.
Response
All safety-related concrete masonry walls have been constructed as either single or multi-wythe hollow or solid block walls with full mortar bedding of the
- units using running bond construction.
No cavity wall construction has been used.
The wythes in multiple wythe walls have been bonded together using a combination of the following techniques:
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A.
Full mortar collar joints B.
Continuous truss bearing reinforcements which overlaps the adjacent wythes every second course.
C.
The use of concrete masonry header blocks.
,7 Concrete masonry wall construction for LaSalle County, Units 1 and 2, was performed under Sargent & Lundy Specification !!o. J-2598.
This document, describing in detail the concrete masonry construction practices employed, was submitted by Commonwealth Edison Company to the NRC under reference letter 2.0B.
The effect of voids in mortar joints on the structural strength of the masonry walls was addressed in a report dated
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t September 23, 1982, submitted by Commonwealth Edison Company to NRC with transmittal dated September 30, 1982.
This report was written in response to additional information requested by NRC on masonry wall design based on the NRC's field visit to LaSalle County Station i
during the week of August 23, 1982.
Based on the information presented ih the report,
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it is concluded that 10% voids in bed joints and 25% voids in collar joints'and head joints can be allowed without impairing the structural integrity of the masonry walls at LaSalle County Station.
These permissible percentages of voids do not have any significant effect on the stiffness and hence, the dynamic response of the wall.
Although the shear stresses are affected by the presence of voids, the increased shear stress due to the above mentioned permissible percentages of voids in mortar joints is still within the allowable value.
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