ML20023A420
| ML20023A420 | |
| Person / Time | |
|---|---|
| Site: | 05000000, South Texas |
| Issue date: | 04/25/1980 |
| From: | Stello V NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Bradford P NRC COMMISSION (OCM) |
| Shared Package | |
| ML20023A411 | List: |
| References | |
| FOIA-82-603 NUDOCS 8005140296 | |
| Download: ML20023A420 (3) | |
Text
'
- $myk UNITED STATES r
e f I t e.
g a NUCLEAR REGULATORY COMMISSION i
f WASHINGTON. D. C. 20555 g w,/
APR 2 51980 MEMORANDUM FOR:
Commissioner Bradford
@gIletD Williani[Dirckt<
THRU:
W. J. Dircks
-~ ~
Acting Executive Director for Operations FROM:
Victor Stello, Jr., Director Office of Inspection and Enforcement
SUBJECT:
CONCRETE VOIDING AT THE SOUTH TEXAS PLANT "r
This is in response to your memorandum on this subject dated April 18, 1980.
The scope of the briefing on April 15, 1980 was to inform the Commission of the results of the investigation into harassment and intimidation of contractor quality assurance personnel and the current effectiveness of the QA/QC program at the South Texas Plant.
As we stated in the briefing, there are some matters related*to the history of this facility which are still under review.
The question of voids is one of those matters.
As indicated below we were aware of the voids in Units 1 and 2 containment structures and knew that their repair was under way.
Similar voiding in these same locations has been observed at other facilities.
With the exception of the voiding problem, no other concrete quality problems were known to exist ano concrete quality at the South Texas Project at this point generally appears to be at least acceptable.
During the repairs a section of liner plate was damaged as a result of water pressure between the liner plate and the concrete.
Water was being used to determine the volume of voids.
This area has not as yet been repaired.
We are and have been aware of the occurrence of extensive' voiding in the Unit 1 and less extensive voiding in Unit 2 containment structures at the South Texas Plant.
The licensee has reported on concrete voiding in 50.55(e) reports dated November 20,1978, June 5,1979, July 16,1979, August 15, 1979 and February 18, 1980.
Copies of those reports are enclosed.
In addition, less extensive voiding has been reported in connection with other structures (see enclosed 50.55(e) report dated April 14, 1978).
Region IV has reported on concrete voiding in the enclosed IE Reports 50-498/79-12 and 50-498/80-1.
The largest void in terms of volume identified in connection with Unit 1 containment was located above the equipment hatch below a liner plate stiffener and did not extend through the wall.
There were smaller voids that extended XA Copy Has Beerr Sent to PDR
Contact:
H. D. Thornburg, IE 9 284 4 D4 a
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4 ma e
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through the shell. wall directly beneath the four main steam lines and two 58 inch otameter HVAC penetrations.
The total amount of grout injected into Unit I containment voids was reported to be 10 cubic yards as related to a total concretelvolume of some 20,000 cubic yards in the reactor contain-ment shell.
The voids found in Unit 2 containment were not as large and deep as those found in Unit 1.
One isolated void was reported to vent to outside containment when tested by water pressure.
The voids were located beneath penetrations and/or-the channel and plate stiffeners.
The total. amount of grout injected into these voids was reported to be 2/3 cubic yard.
The above reported voids have structural significance, particularly the more 3.
. extensive voids if not corrected.
The voids penetrating the containment structure have significance in terms of radiation shielding and potential leak
"* S
. tightness of the steel liner if not corrected.-
Secondly, voiding in containment was detected. under the STP quality assurance program and repairs have been controlled.
The licensee has performed an extensive program for detection and repair of voids.
We have followed these matters closely which provides us'with confidence in this area.
Thirdly, the voids were found in' congested locations in terms of reinforcing steel, containment penetrations, and plate stiffeners.
Experience has shown that voiding is not uncommon in this type structure.
I trust that this has been responsive to your request.
' Original Sip *d 3Y R. C. DeYouns
^
D Victor Stello, Jr.
u Director Office of Inspection
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-and Enforcement
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Enclosures:
4 1.
Report dtd 4/14/78 i
2.
Rtport dtd 11/20/78 3.
Report dtd 6/5/79-4.
Report dtd 7/16/79 5.
Report dtd 8/15/79 6.
Report dtd 2/18/80 7.
Report 50-498/79-12 8.
Report 50-498/80-1 cc:
See next'page DD:
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3-cci Chairman Ahearne Commissioner Gilinsky Commissioner Kennedy Commissioner Hendrie SECY OGC OPE Distribution:
W. J. Dircks, EDO E. K. Cornell, EDO T. Rehm EDO V. Stello, IE R. C. DeYoung, IE
"*5
.D. Thompson, IE R. E. Shewmaker, IE
-'c G. W. Reinmuth, IE H. D. Thornburg, IE K. V. Seyfrit, RIV J. P. Murray, ELD IE Files Central Files IE Reading EDO Reading L. Underwood, H11-2240-H06 G. Ertter, EDO-8805 4
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