IR 05000302/1976015
| ML19308D427 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 09/28/1976 |
| From: | Jape F, Robert Lewis, Swan W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19308D418 | List: |
| References | |
| 50-302-76-15, NUDOCS 8002280730 | |
| Download: ML19308D427 (7) | |
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NUCLEAR REGULATORY COMMISSION
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REcsoNss j,y/QQ./,.K 230 PCACllTREE STREET. N.W. SUWE 813
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f IE Inspection Report No. 50-302/76-15 Licensee: Florida Power Corporation 3201 34th Street, South Post Office Box 14042 St. Petersburg, Florida 33733
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l Facility Name:
Crystal River 3
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Docket No.:
50-302 I
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License No. :
CPPR-51
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Category:
B1 t
I.ocation: Crystal River, Florida Type of License:
B&W, PWR, 2452 Mwe Type of Inspection: Special. Announced V
Dates of Inspection: August 19-20, 1976 Dates of Previous Inspection: August 17-19, 1976 Inspector-in-Charge:
W. B. Swan, Reactor Inpsector Engineering Support Section No. 1 Reactor Construction and Engineering Support Branch Accompanying Person:
T. E. Conlon, Chief Engineering Support Section No. 1 Reactor Construction and Engineering Support Branch
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Other Accompanving Personnel: None g.
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Principal I.. pector:
F. Jape, Reactor Inspector Date Reactor Projects Section No. 2 Reactor Operations and Nuclear Support Branch
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j Reviewed By:
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R. C. Lewis, Chief Date Reactor Projects Section No. 2
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Reactor Operations and Nuclear t,
Support Branch
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IE Rpt. No. 50-302/76-15-2-i f
SUMMARY OF FINDINGS
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I.
Enforcement Items There were no items of noncompliance identified during the inspection.
II.
Licensee Action on Previously Identified Enforcement Matters
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Not inspected
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III. New Unresolved Items
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None i
IV.
Status of Previously Identified Unresolved Items
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Not inspected i
V, Design Changes See Details, paragraphs 3 & 4 VI.
Unusual Occurrences None VII. Other Significant Findings None VIII. Management Interview
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A management interview was held on August 21, 1976, with
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Mr. B. L. Griffin, Vice President and Program Manager, and other
representatives of the corporate and site staffs. The findings of the inspection were discussed,
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IE Rpt'. No. 50-302/76-15-1-
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DETAILS Prepared by: {38-bC k
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9-2 7-78
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W. B. Swan,- Reaccod Inspector Date Engineering Support Section No. 1 Reactor Construction and Engineering Support Branch Dates of Inspection: August 19-20, 1976 Reviewed by d i b
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T. E.'Conlon, Chief Datc
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Engineering Support Section No. 1 l
Reactor Construction and Engineering l-Support Branch L.
Individuals Contacted a.
Florida Power Corocration (FPC)
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E. L. Griffin - Vi,ce President and Program Manager
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J. T. Rodgers - Assistant Vice President M. H. Kleinman*- Director, Quality Programs E. E. Froats - Manager, Site Surveillance R. S. Dorrie - Quality Engineer D. W. Pedrick, IV - Compliance Engineer C. E. Jackson - Construction Superintendent T. L. Baker - Supervisor, Quality Records W. W. Nisula - Structural Engineer
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C. Pachos - Architectural and Structural Superintendent D. W. Bienkowski - Engineer b.
Contractor Organizations Gilbert Associates Com=onwealth Corcoration (GAI)
J. C. Herr, P.E. - Structural Engineer F. L. Moreadith - Supervisor of Technical Services and Project Manager for dome repair 2.
Scope of Inspection This special, inspection was made to determine licensee's progress
on repair of' the containmc.+.t dome and included review of the licensee's interim reports of this 10 CFR 50.55(e) matter, specifications, field change notices and the FPC work procedure for repair of the dome.
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IE Rpt. No. 50-302/76-15-2-
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The facilities for testing varioun types of radial anchors were inspected and the techniques discussed; removal of the upper concrete dome caps was observed and the condition of the upper surface of the exposed lower dome section was inspected.
3.
Dome Repair - Documents Reviewed GAI Specification SP-6476 " Removal and Replacement of Concrete, C.R. Unit No. 3, Florida Power Corporation, August 5,1976" GAI Specification SP-6467 " Radial Anchor Test Program" Title No. 69.2 " Criteria for Reinforced Concrete Nuclear Power Containment Structures" reported by ACI Committee 349, ACI Journal for January 1972.
FPC CR No. 3 Work Procedure FPC W-200 " Repair of the Reactor Building Dome, Rev. 6, August 6, 1976," and eight field changes issued to August. 10, 1976, some of which will be incorporated in next revision of W-200.
The need to keep the approved procedure current with the
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work was discussed with the-licensee.
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Amended pages dated August 10, 1976 to FPC Crystal River No. 3 Dome Delamination Report dated June 11, 1976, transmitted to NRC Division of Project Management by letter of August 16, 1976 Supplement No.1 to this report containing FPC's responses to NRC-DPM questions on the original report Catalog of William's Expanding Anchors 4.
Calculations of Tensile Stresses in Concrete Paragraph 1.2, " Summary and Conclusions," of the Dome Delamination.
Report, dated August 10, 1976, gives calculated values of radial tension stresses in the original dome from potential contributing factors. The summary stres:-2s in some additive combinations approach the indicated concrete tensile strength of 700 psi for cured concrete.
Paragraph 3.4, " Conclusions," pages 3-11, dated August 10, 1976 states:
"The delaminated surface indicates a tension failure. The complete fracture of the coarse aggregate on this surface and the variations in the strength values obtained from the direct i
tensile tests indicate that the fragility of this aggregate ould have contributed to the fracture.
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IE Rp t. No. 50-302/76-15-3-
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The studies reported in th previous sections suggest a nesber of other factors, including secondary stresses associated with shrinkage and thermal effects, could have increased the average stress values to levels in excess of the concrete tensile strength. The studies also indicate that, if it existed, tendon misalignment may be sufficient to produce cracking.
No single or overriding mechanism has been positively identified as the cause of the delamination.
Analysis is continuing in pursuit of further definition as to the cause."
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Since only 15% of the dome endons have been detensioned, the stresses imposed by tendon stressing on the new dome cap concrete are expected to be only about 15% of the stresses imposed on the original concrete. This reduced loading and the installation of 1800 radial anchors are expected to insure the service intetrity of
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the structure. The joint between new and old concrete will be made
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with epoxy so the new joint is expected to be stronger than the original concrete.
5.
Crack Mapping of Concrete Below the Maior Separation (Delanination)
Boroscope examination of 1840 bore holes for future anchors had.
been made. During the inspection the cracking data were being plotted on dome map in various colors indicating the depths of detected crac;3. A decision had not been reached to attempt to determine the interhole connection of cracks at various depths of the concrete. The repair plan calls for epoxy grouting of these subsidiary cracks.
8.
Radial Anchors Test Prcaram Concrete blocks 10'X12'33' thick are being used to test various types of anchors grouted in by cement grout or epoxy. The testing program is continuing and a decision as to the type of anchor and grout to be used and the diameters of the holes has not been made.
A GAI engineering letter dated August 8,1976, directed that SP-6467
" Radial Anchor Test Program" be revised as follows:
Omit some tests on bolts proved unsuitable in other test sequences.
a.
b.
To test deformed rod (1 3/8" Williams) utilizing unsanded grouts and epoxies.
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Use epoxy 350, sa=e type as used to seal cracks.
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IE Rpt'. No. 50-302/76-15
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Add two test sets in 10" and 15". deep holes (2 tests each) one inch in diameter using ' o. 6 Grade 60 rebar.
Test No. 7 Grade 60 bar in 10" holes and 15" holes two inches a.
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in diameter.
Revisions of the repair procedure have been made as soon as practical after engineering decisions and prior to safety related work.
7.
Concurrent Insoection by Architect Engineer-
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GAI has maintained as resident structural engineer following the investigative work and removal of concrete. FPC has a structural i
engineer providing regular surveillance. On Friday, August 20, 1976, a team of GAI HQ engineers and consultants were observed
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making a visual inspection of the dome work and exposed surfaces.
The NRC inspector did not participate in their inspection or dis-
cussions and their findings are not yet available to IFE.
8.
Observation of Work
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Two inspections were made of concrete removal and of the surfaces l
of exposed concrete. These inspections provided evidence that adequate quality control procedures exist and are.eing impicmented.
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l No noncompliances with quality requirements were noted.
9.
Activities Remaining to Be Done
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The inspector stressed the need for documentation of test data a.
on the selected anchor system for his review.
(1) Decide on anchoring system and modify procedure to suit.
(2) Choose aggregate for new dome concrete and qualify mix.
b.
Grout lower level cracks with epoxy
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c.
Set radial anchors and grout holes d.
Reestabl,ish upper rebar grid and replace concrete dome cap
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Cure concrete 28 days
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Retension 18 tendons
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l-IE Rp t. No. - 50-302/76-15-5-
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Perform Containment Integrity Test
t Present indications are that integrity testing will be done, dome j
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December 1976 about one year from the presumed date of the
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