IR 05000269/1982018
| ML20055A208 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 06/10/1982 |
| From: | Ang W, Economos N, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20055A179 | List: |
| References | |
| 50-269-82-18, 50-270-82-18, 50-287-82-18, IEB-79-02, IEB-79-14, IEB-79-2, NUDOCS 8207150574 | |
| Download: ML20055A208 (5) | |
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UNITED STATES'
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h'g NUCLEAR REGULATORY COMMISSION REGION il 3,
- . C 101 MARIE TT A ST.. N.W. SulT E 3100
ATLANTA, GEORGI A 30303 0s...../
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Report Nos. 50-269/82-18, 50-270/82-18 and 50-287/82-18 Licensee: Duke Power Company
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P. O. Box 2178
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Charlotte, NC 28242 Facility Name: Oconee Units 1, 2 and 3
Docket Nos. 50-269, 50-270 and _50-287
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i License Nos. DPR-38, DPR-47 and DPR-55
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Inspection at Duke Power Company site near Charlotte, North Carolina Inspectors: N G
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W. P Ang Date Signed
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J.J.
enaha Date Signed do A-
Approved by:
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h 7.f(conomos Acting Section Chief
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/ Engineering Inspection Branch
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Division of Engineering and Technical Programs
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SUMMARY
Inspection on May 18-21, 1982 Areas Inspected l
This routine, announced inspection involved 48 inspector-hours on site in the
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areas of seismic analysis for as-built safety-related piping systems (IEB 79-14);
and Pipe Support Baseplate Designs Using Concrete Expansion Anchor Bolts (IEB
79-02).
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Of the areas inspected, no violations or deviations were identified.
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j 8207150574 820614
$DRADOCK 05000269
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REPORT DETAILS 1.
Persons Contacted Licensee Employees
- S. B. Hager, Chief Engineer, Civil Engineering Division
- D. L. Rehn, Principal Engineer, Structural Analysis and Design Section
- A. P. Cobb, Principal Engineer, Civil Engr. Division R. B. Priory, Principal Engineer, Project Management Division
- J. F. Kutzer, Senior Engineer, Licensing
- L. Coggins, QA Engineer R. L. Cope, Supervising Design Engineer D. M. Rogers, Supervising Design Engineer T. Bradley, Supervising Design Engineer J. E. Brewer, Supervising Design Engineer M. S. Sills, Supervising Design Engineer T. A. Mathews, Senior Engineer N. Whitaker, Technical Associate T. D. Brown, Engineering Assistant
- Attended exit interview 2.
Exit Interview The inspection scope and findings were summarized on May 21, 1982, with those persons indicated in paragraph 1 above. The inspector described the areas inspected and discussed in detail the results of the inspection as noted below. The licensee had no dissenting comments.
(Closed) Inspector Follow-up Item 79-13-01 - Inspections Required by IE Bulletin 79-02 (Paragraph 5).
3.
Licensee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unresolved items were not identified during this inspection.
5.
Seismic Analysis for As-Built Safety Related Piping Systems (IEB 79-14)
A follow-on inspection to NRC RII report numbers 50-269/81-20, 50-270/81-20 and 50-287/81-20 was performed to verify licensee compliance with IEB 79-14 requirements and licensee commitments.
An inspection to determine the extent of contract (non-DPC) personnel involvement was performed.
The licensee stated that a contract engineering services company (Nuclear Power Services) was being used by DPC. However, only one person was ir.volved in
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the Oconee IEB79-14 analytical work. A review of the contracts with Nuclear Power Services (NPS) revealed that:
(a) All NPS work was required to be performed in DPC offices under DPC management and supervision (b) All NPS work was performed in accordance with DPC engineering and
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design standards and under the DPC QA program (c) DPC screened and selected NPS personnel assigned to work for DPC.
The following were inspected to verify licensee compliance with IEB 79-14 requirements and licensee commitments. Unit I stress problem for modifica-tion numbers 783 and 1012 - Auxiliary Service Water piping unit 2 stress problem number 51-2 - High Pressure Injection piping associated walkdown discrepancies were sampled and corresponding operability reviews inspected.
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The inspection and discussions with the licensee confirmed that operability i
reviews had been performed for the walkdown discrepancies.
The licensee stated that all piping re-analysis and pipe support re-analysis have been completed.
However, the licensee stated that although operability is
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assured, repairs are still being made to pipe supports to comply with code requirements. These repairs are scheduled to be complete by the end of the
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1983 unit 2 outage.
The licensee stated that a final IEB 79-14 response I
will be submitted and will provide a schedule for completion of the remaining work and will categorize types of work still to be completed.
NRC/RII report numbers 50-269/81-20, 50-270/81-20 and 50-287/81-20 noted i
that piping analysis problems employed an overlap modeling technique that
differed from NUREG 51357.
Inspection of the above noted High Pressure
Injection Piping analysis problem and subsequent discussions with the
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licensee revealed the following.
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a)
Stress problems have now been modelled with five or more rigid j
restraints in each of the three perpendicular directions.
b)
The overlap regions were chosen with consideration for problem relative i
stiffness. However, the response spectra for the overlapping problems l
were not enveloped.
The fundamental frequency of the overlap region was not specifically evaluated.
c)
Support loads in the overlap region are now enveloped but are not
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increased by ten percent.
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The above noted information will be forwarded to NRR for evaluation and resolution.
Item 4.d of IEB 79-14 requires that quality assurance procedures be evalu-l ated and improved to assure that any modification to piping and pipe supports are reflected in their respective analysis.
Procedure QA-510 Revision 4 QA Review of Station Work Requests, did not include specific
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requirements for reinspection of piping and pipe supports disassemblies for maintenance. The licensee committed to review QA procedures to provide a requirement for re-inspection of piping and pipe supports disassembled for maintenance to assure that any modifications that may have been performed during maintenance are adequately reflected in their respecitve analysis.
Pending license completion of all IEB 79-14 requirements, the bulletin was lef t open. No violations or deviations were identified.
6.
Pipe Support Baseplate Designs Using Concrete Expansion Anchor Bolts (IEB 79-02)
A follow-on Inspection to NRC/RII report numbers 50-269/81-20, 50-270/81-20 and 50-287/81-20 was performed to verify licensee compliance with IEB 79-02 requirements and licensee commitments.
These reports noted that the licensee allowed an 80 percent ultimate capacity reduction for concrete expansion anchors that had high shoulder to plug measurement but passed a 1/4 ultimate capacity pull test.
The licensee analytical evaluation and resolution was discussed.
Subsequent to the inspection, the licensee reported that the 80 percent reduction was confirmed by testing performed at the University of Tennessee.
The licensee reported that further review revealed that approximately 160 concrete expansion anchors per unit were in this category and was distributed approximately as one bolt per base plate.
The licensee further stated that the average calculated safety factor for these concrete expansion anchors was 42.4 with the minimum being 6.25 when compared to 80% of its ultimate capacity. The licensee committed to submit this information on its final bulletin response.
The licensee further agreed to annotate the baseplate calculation involved to clearly identify the condition noted so as to assure that future modifications or re-analysis will include the noted condition for re-analysis.
The inspector had no further questions regarding inspector follow-up item (IFI) 287/79-13-01 and closed the IFI.
Pending completion of all IEB 79-02 requirements and licensee commitments, IEB 79-02 was lef t open.
No violations or deviations were identified.
7.
License Identified items (LER)
(0 pen) LER (270/82-07) Broken Vertical Tendon in Secondary Shield Wall On April 28, 1982, during inspection of the Unit 2 Reactor Building interior, one vertical tendon in the removable portion of the secondary shield wall was found broken. Subsequent inspection of the vertical tendon in the Unit 2 and 3 secondary shield walls disclosed that one additional tendon was broken in the Unit 2 wall. There are eight vertical tendons in the removable secondary shield wall. None were found to have failed in the Unit 2 wall. However some vertical tendons in both walls were found to be corroded. The licensee concluded based on inspection of the tendons, that
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the cause of the broken tendons was stress corrosion caused by water accumu-lation in the bottom of the vertical tendon sheaths.
The designer of the Reactor Building, Bechtel, performed a preliminary design evaluation of the removable portion of the secondary shield wall.
The preliminary design evaluation disclosed that the primary strength of this portion of the secondary sheild wall to resist the design loads is provided by reinforcing steel embedded in the concrete and horizontal tendons. Therefore the loss of prestressing force in the vertical direc-
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tion does not prevent the shield wall from performing its design function.
However the licensee has replaced the two broken vertical tendons and four additional Unit 2 tendons which were found to be corroded. The grease caps and shims at the bottom of the vertical tendons have also been modified to permit drainage of water which may enter the vertical tendon sheath. This will prevent water from accumulating and causing corrosion of the tendon wires. The licensee also inspected one Unit 2 horizontal tendon, the second from the bottom of the wall. This tendon was found to be acceptable.
The inspector discussed this problem with licensee engineers.
These discussions disclosed that the Unit 3 tendons which were found to be corroded will be replaced prior to restart up of Unit 3 (Unit 3 is presently shut down). A surveillance program will also be implemented to inspect the tendons in the vertical shield walls.
In addition, a detailed finite element analysis will be performed to confirm the findings of the prelim-inary design evaluation, and an inspection will be made of the Unit 1 vertical tendons during the next outage.
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