ML19290A413
| ML19290A413 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 02/02/1972 |
| From: | John Miller METROPOLITAN EDISON CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19290A412 | List: |
| References | |
| NUDOCS 7911070592 | |
| Download: ML19290A413 (5) | |
Text
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& 4 -.-m METROPOLITAN EDISON COMPANY sue:ioisav or aenenst ruaticuritoriesconronarion FC3T CFFiCE BOX 542 AExUmU, rnNNW.V ANI A lbOVJ TELEPHONE 215 - 929-3601 February 2, 1972 United States Atomic Energy Coc=ission Division of Compliance, Region 1 970 Broad Street Newark, New Jersey 07102 ATTENTION:
Mr. James P. O'Reilly, Director
Dear Mr. O'Reilly:
SUBJECT:
AEC DIVISION OF COMPLIANCE INSPECTION LETTER OF JANUARY 5, 1972 DOCKET No. 50-289 AEC CONSTRUCTION PERMIT NO. CP-PR-40 We have your letter of January 5,1972 concerning a Dece:ber 16-17, 1971 Division of Compliance Inspection of construction activities and a finding of non-conformance with a statetent in the Final Safety Analysis Report. The findings report non-conformance with concrete during requirements of ACI-301-66 during containment dome construction and violations of Sections 1405 and 1201 of the Code.
We have reviewed these findings and believe that there is no violation of the Final Safety Analysis Report.
Coccents regarding the inspection findings and the basis for our position follow:
The area in question, Seg=ent 4 of the reactor building doce concrete, was placed and cured as shown on the attached bar chart. The total hours of curing before uncovering this segment varies as shown from 39 to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The total curing time was a full seven days.
In accordance with the Engineers recoceendation letter for the place-cent of doce concrete, issued April 30, 1970, concrete placement of doce rings should not proceed until previous concrete placeeent reaches a minimun strength of 3000 psi.
Field cured concrete cylinders for Segment 4 reached the strength of 3080 psi on the morning of December 17, 1971.
1555 313 7911070 N )
1
United States Atomic Energy Coc=ission Division of Co=pliance, Regica 1 Cleaning operations, in preparation for place =ent of Segment 5, coamenced at 3:15 P.M. on Dece=ber 16, 1971 and Seg=ent 4 was uncovered for a distance of 24 to 30 inches to assure water from the wet curing blanket would not run down the vertical face and accumulate on the do=e liner plate, hindering the cleaning operation. At approxi=ately 5 :15 P.M. the exposed concrete was recovered to the leading edge and wet down. Wet curing on the vertical face was accomplished by =eans of pressurized back pack sprayers, adjusted for a fine mist to prevent an accumulation of water on the do=e liner plate.
On Dece=ber 17, 1971, the vertical face was allowed to dry ahead of the place =ent of Seg=ent 5 to apply epoxy at 60*F minimum as required by the Engineering Concrete Specification, SP-5406, Addendum E.
The entire do=e place =ent was enclosed and attended by curing gangs, three shif ts, seven days, to assure that proper curing conditions were maintained at all times. The presence of water used in curing was conducive to a high hu=idity, therefore, no har=ful drying of the concrete mass is believed to have occurred in the two hours required for the cleaning ope rations.
During the curing of Seg=ent 4, the Pittsburgh Testing Laboratory made daily inspections of the cure until Dece=ber 21, 1971, as the laboratory curing report attests. Place =ent of the done concrete was co=pleted on January 5, 1972.
We have perforced a Swiss Ha=ner test at four locations in emch quadrant of Seg=ent 4 to ascertain if any variances occurred in the strength of the concrete between the area which had been uncovered for two hours and the area that was continuously covered. The following results were obtained:
NOTE:
LOCATION UPPER - Concrete surface of Seg=ent 4 at one foot below construction joint between Seg=ents 4 and 5.
LOWER - Concrete surface of Seg=ent 4 at two feet above construction joint between Seg=ents 3 and 4.
- Each pair of test areas was located on the sa=e r.!.muth.
CONCRETE SURFACE CONDITION
- Concrete surface in area of test was rough.,
1555 314
United States Atomic Energy Commission Division of Compliance, Region 1 TEST AREA LOCATION COMPRESSIVE STREL~rH - PSI 1
UPPER 6290 2
LOWER 6200 3
UPPER 5400 4
LOWER 5360 5
UPPER 5560 6
LOWER 5140 7
UPPER 5510 8
LOWER 5440 9
UPPER 5580 10 LOWER 4460**
- 11 UPPER 6230 12 LOWER 5130 13 UPPER 5730 14 LOWER 5280 15 UPPER 4270**
16 LOWER 4560**
An additional test was perfor=ed on two randomly selected five foot square areas of Segment 5.
These areas were wet down with water and allowed to dry. Representatives of CPU and UE&C performed a visual inspection as the concrete dried. No evidence of surface cracks was observed. The drying pattern appeared uniform over each of the five foot square areas.
On December 17, 1971, following the findings as reported by the Division of Compliance inspector, Civil Supervisors were oral!y instructed that curing blankets could only be rolled back as far as necessary to perform the cleaning operations and be replaced as soon as possible.
In addition to the oral instructions issued on December 17, 1971, a letter has been issued emphasizing those instructions.
1555 315 e
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United States Atocic Energy Co _lssion Division of Compliance, Region 1 Clarification of specifications were i=ple ented Dece=ber 17, 1971 to assure that all activities fully comply with specification requirements.
Verytrulyyours,l r.
l V
i m
!lG. Miller 0W/ V Vice President Att: Placement & Curing-Reactor Building Doce Concrete.
1555 516 a
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PLACEMENT AND CURING - REAC'lDR
- BUILDING DOME CONCRETE T
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PLACE!!ENT & CURING DECEMBER 14, 1971 DECEMBER 15, 1971 DECEMBER 16, 1971 DECEMBER 17, 1971 SECMENT 4 O2 6; m A.M.
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CIRCUMFERENTI AI, JOINT 12:00 Midnight 36 Il0UR.i 12:00 Noon MIN. CURE PRIOF TO
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