ML20058D989
| ML20058D989 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 07/20/1982 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 4555N, NUDOCS 8207270459 | |
| Download: ML20058D989 (3) | |
Text
\\t-
's Q Commonwealth Edison
) ons First NationIl Plaza, Chica0o. lilinois
's O
Address Reply to: Post Office Box 767 Chicago, Illinois 60690 3
Jul y 20, 1982
\\
\\
s Mr. Harold R.
Denton, Director E,.
~
Of fice of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission ~
\\
~
Washington, DC 20555
Subject:
Byron Station Units 1 and 2 Essential Service \\ Water Pipeline Founda tio n NRC Docket No s. 50-454 and 50-455 Re ference (a):
June 1,1982 letter from B. J. Youngblood to L. O. DelGeo rge.
Dear Mr. Denton:
s This is to request clarification of the acceptance criteria proposed for the slanted borings atsByron Station which were requested by the NRC.
Attachment A to this letter documente our understanding o f the criteria contained in enclosure 2 of reference (a).
NRC concurrence on these points is requested so that we can respond properly to the questions contained in enclosure 1 of reference (a).
Please contact this office if there are anysquestions regarding this matter.
One signed original and fif teen c les of this letter and the attachment are provided for your review.
Ve ry truly yours, t
o
[
/
v 4
Tramm Nuclear L uf
, >g Adminis trato r 1m x
Attachment A l
3 00 4555N 8207270459 820720 PDR ADOCK 05000454 l
A PM
ATTACHMENT A 3
s SPECIFIC ACCEPTANCE CRITERI A FOR BYRON BORINGS
~ 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 feet maximum width.
b.
Filled joints.
c.
The percentage of open joints in a 50 foot rock coring is less than 20% in the upper 40 feet of rock.
d.
The induced pipe stresses due to loss of s _.
foundation support or differential settlement are conservatively shown to be within code limits.
Clarification:
a.
Any joint with an opening o f 4.5 feet or less is acceptable.
b.
Filled joints o f any width are acceptable.
c.
If the percentage of open joints in 50 feet of rock coring, beginning at the rock surf ace, is less than 20% in the upper 40 feet of rock, the rock is acceptable.
Measurement of npen joints is determined primarily by measured rod drops.
Other factors which will be examined will be changes in bit rotation speed, changes in rate of _ drill rod advancement, and coincident loss of drilling fluid.
All data collected during the boring program will be evaluated to determine the percentage of open joints in the upper 40 feet of rock.
If this data indicates that the percentage of open joints is greater than 20%, in situ measurements will be performed.
Summation o f core 192 recovery will not solely be used for evaluation of this criteria.
d.
The induced pipe stresses due to differential
~
settlement are conservatively shown to be within code limits.
The codes applicable to the pipeline are ASME Section III Division 1, Subsection NC for the unencased pipe, and ACI-318 f or the concrete encased pipe.
4555N J
- Acceptance Criteria 2:
If open joint width (W)> 4.5 feet, additional rock and soil exploration is needed along the pipeline where it is supported on soil.
Staff will accept the foundation adequacy if the results show that:
a.
Alluvial support depth is at least 2W below pipe.
b.
If alluvial support depth 2W, grout unreinforced run where voids encountered.
Clarification:
The applicant's understanding of this criteria is that W refers to horizontal joint width and that alluvial support actually means all glacial deposits and residuum.
4555N