ML20128P216
| ML20128P216 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/10/1985 |
| From: | Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| F0754A, F754A, SD-81, NUDOCS 8506030487 | |
| Download: ML20128P216 (2) | |
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(203) 66s-5000 May 10,1985 Docket No. 50-423 F0754A Dr. Thomas E. Murley Regional Administrator U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e):
Structural Steel Connections in the Main Steam Valve Building (SD-81)
In an April 12,1985 telephone conversation between your Mr. T. Rebelowski and our Mr. P. 3. Quinlan, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the construction of Millstone Unit No. 3 in accordance with 10CFR50.55(e). The potential significant deficiency involves structural steel connections in the Main Steam Valve Building (MSVB).
During the NRC Construction Appraisal Team (CAT) inspection at Millstone Unit No. 3, a concern was identified regarding undersized fillet welds on the clip angles for three (3) W14 x 68 beams welded to embedded plates for the structural steel installation in the MSVB. The clip angles are welded to the embedded plates with at least a 5/16" fillet weld,1 side with 1" end returns. A 7/16" fillet weld, 3 sides is required for W14 beams.
Further investigation revealed a connection for the 49' 0" platform at 14'0" north of 45.8 line to be detailed on the design drawing as both a fixed an'] slotted connection. This was later found to be an isolated case.
The typical end connection detail also requires a 3 sided, 5/16" fillet weld for W12, W10 and C12 beams. An inspection of all beam end connections in the MSVB was performed. The results of the inspection indicate that 96 fixed-end connections, previously inspected and accepted by Stone & Webster Field Quality Control (FQC), were found to be installed to the incorrect welding detail (i.e.,
clip angle wc!ded to embedded plate with I sided versus 3 sided fillet weld). The nonconforming conditions were found at the el. 49'0", 53'0" and 58'0" platforms.
The inspectian also revealed bea'ns with slotted connections to have bolts tensioned beyond the finger-tigh't requirement of the design drawing.
An inspection of all required slotted connections identified 70 connections previously accepted by FQC, which did not have firger-tight bolts, peened threads and cover plate washers.
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le. Due l to the particular design of structural connections in the MSVB, it is expected that these conditions are limited to this building. However, a sampling
- of connections in other QA Category I buildings will be performed to verify this.
We are not able to provide a final report at this time. We will provide an update
- on this matter by July 11,1985.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY b
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J. F. ObeWa O
Senior Vice President
.cc:
Mr. 3. M. Taylor, Director
- Division of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D. C. 20555
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