IR 05000259/1980038
| ML19290G653 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/05/1980 |
| From: | Colon T, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML19290G651 | List: |
| References | |
| 50-259-80-38, 50-260-80-32, 50-296-80-32, NUDOCS 8012180223 | |
| Download: ML19290G653 (3) | |
Text
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Report Nos. 50-259/80-38, 50-260/80-32, and 50-296/80-32 Licensee: Tennessee Valley Authority 500A Chestnut Street Chattanooga, TN 37401 Facility Name:
Browns Ferry Nuclear Plant Docket Nos. 50-259, 50-260, and 50-296 License Nos. DPR-33, DPR-52, and DPR-68 Inspection at Browns Ferry site near Decatur, Alabama Inspector n
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J. J. Lenatan e
Date Signed Approved by M
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,5~- f e T. E. Conlon, Section Chief, RC&ES Branch Date Signed SUMMARY Inspection on October 14-15, 1980 Areas Inspected This special, unannounced inspection involved 8 inspector-hours on site in the area of a licensee identified item concerning settling of structural backfill under the RHR Service Water Tunnels.
Results Of the area inspected, no items of noncompliance or deviation were identified.
L s 01e180 DETAILS 1.
Persons Contacted Licensee Employees
- J. L. Harness, Assistant Plant Superintendent J. Swindell, Outage Director D. Nye, Manager, IEB 79-02 and 79-14 J. Smithson, Civil Engineer NRC Resident Inspector
- R.
F. Sullivan J. Chase
- Attended exit interview 2.
Exit Interview The inspection scope and findings were summarized on October 15, 1980 with those persons indicated in Paragraph 1 above.
3.
Licensee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unreso;ved items were not identified during tinis inspection.
5.
Licensee Identified Item (LER)
The inspector performed a special unannounced inspection to examine the licensee's investigation and corrective actions as a result of settlement of structural backfill under the RHR Service Water piping tunnel.
This was reported to NRC Region II and the Resident Inspector on October 10, 1980, as LER number BFRO-50-259/80-77.
The licensee's investigation of settlement of a non-safety related venti-lation structure on the south side of the plant disclosed that the floors of the RHR service water piping tunnels has settled up to 14 inches.
This investigation also disclosed that some of the seismic restraints for 'he RHR service water piping had been anchored in portions of the tunne t floor slabs which sellted, and not in seismically qualified footings.
Pralimina ry survey measurements indicate that the seismically qualified footings, which are supported on piles driven to top of rock, have not settled.
In order to correct the problem, the licensee performed a seismic analysis on the worst case basis and designed a modification to the seismic restraints. The design analysis showed that adequate safety factors existed until the modifications were completed. This modification consisted of a new base
-2-plate anchored on the seismically qualified footing by 4 one-inch diameter wedge bolts. The new base plate is connected to the existing seismic restraints on the RER service water pipes by shear brackets. All connections are made by welding.
The modifications had been completed on the seismic restraints in the three west piping tunnels as of the date of this inspection. The modifications were in progress on the three east tunnels.
The licensee stated that this work would be completed by October 17, 1980.
The inspector examined the procedure covering the restraint modification work and drawings showing details of the modifications. The procedure covered :ontrol of materials, a list of welders qualified to perform the necessary welding, and the specifications for welding and installation of the edge anchors.
The plant QA staff was performing a 100% visual inspec-tion of the welds, and a 100% inspection of anchor bolt installation.
The inspector discussed the settlement problem with responsible licensee engineers.
The following items will be addressed by the licensee in a written follow-up report covering this LER:
a.
The probably cause of the settlement.
b.
The effect of the settlement on the piles supporing the seismically qualified footings.
A discussion of settlement monitoring program the licensee plans to c.
initiate to determine if settlement of the piping tunnels is still occurring.
d.
A review of other areas in the plant to determine if other Category I utility lines (e.g. diesel fuel oil, electrical ducts, etc) may have experienced settlement in the past which may have resulted in com-promising their original design requirements.
The written report will be submitted as required under Technical Specifica-tions.
No deviations or items of noncompliance were identified.