ML19347B507
| ML19347B507 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/14/1980 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19347B501 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8010150203 | |
| Download: ML19347B507 (4) | |
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'Af (412) 454 4000 435 Sixth Avenue Pittaturgn Pennsytynnia 15219 August 14, 1980 United States Nuclear Regulatory C = mission Region I 631 Park Avenue King of Prussia, PA 19406 i
ATTEITION:
MR. BOYCZ H. GRIER, DIRECTCR
SUBJECT:
Beaver Valley Pcwe. Station - Unit No. 2 Docket No. 50-412 Linear Indications in Gib Gusset Welds in Reactor Vessel Structural Support (Neutron Shield Tank)
Significant Deficiency 80-03 Gentlemen Inclosed is the " Interim Report on Linear Indications in Gib Gusset Welds in Reactor Vessel Structural Support (Neutron Shield Tank) at Seaver Valley Pcwer Station - Unit No.
2".
We plan to issue another interim report on November 1, 1980.
DUQUESNE LIGHT COMPANY By % */
Ef J. Woolever VICE PRESIDCIT Enclosure cc:
Dr. V. Stello (1S) 801015 0c2O M
4 Interim Reoort 9!!
Linear Indications In Gib Gusset Welds in Reactor Vessel Structural Supeort (Neutron Shield Tank)
At, Beaver Valley Power Station - Unit No. 2 1.0 Sunnaary A linear indication was found by magnetic particle (MP) examination of a weld connecting a gib gusset to the reactor vessel support structure top plate. The indication was partially excavated and the defect found to be j
extensive in that weld. Additional linear indicatiens were found through MP examination of other similar welds.
2.0 Immediate Action Taken Approximately 1S in. of the initial iMication, which extended the entire length of the gib gusset weld, was partially excavated to clear the indication leaving approximately 6 in. of weld defect af ter excavation.
Approximately 6 in, were left unexcavated. The results of this grinding effort were evaluated and notification of the potentially reportable deficiency was made to NBC Region 1 on July 17, 1980, under the provisions of 10CFR50.55(e).
3.0 Description of ceficiency In the process of performing magnetic particle (MP examination of the reactor vessel structural support (RUSS) top plate, subsequent to removal of two (2) temporary lifting lugs, a linear indication was found to exist on a nearby gib gusset weld. Further MP examination of the gib gusset veld, after paint removal, revealed that the indication extended the entire
~2-length of the weld attaching tne inner gib gusset to the top surface of the RVSS. Additional MP inspection was performed at the remaining eleven (11) inner gib gusset locations.
The additional inspection revealed one additional gib gusset weld where a linear indication extended the entire length (approximately 21 in.).
Of the remaining ten (10) inner qussets, two welds contained no indications and eight welds contained intermittent indications, ranging in length from fractions of an nch to several inches.
Finany, magnetic particle examination en twelve (12) outer guaget welds resulted in an the gusset welds exhibiting intermittent indications of various lengths.
The initial linear indication appeared to be confined to the base metal heat affected :ene of the 7 in. thick top plate beneath the weld joining the 21/2 in. thick gib gusset to the top surface of the top plate. Excavation to a depth of approximately 1 in. as measured along the heat affected :ene cleared an except a 6 in. length of the indication. Since it was difficult to establish the cause of the weld defect, based on grinding and subsequent i
i surface examinatien, a sample of the defective weld win be removed for i
metanurgical evaluation to characteri:e the defect.
4.0 Analvsis of Safety Imolications Analysis of safety implications win be provided in the final report.
5.0 Corrective Action to Remedy Deficiencv Pending the outccme of the metallographic analysis of the weld sample, additional inspections of the gib gussets will be performed to determine the extent of weld repair required.
All linear indications win be removed and an weld excavations will be j
rewelded and magnetic particle inspection in accordance with the original specificatien requirements.
Repairs will not be started until metal-icgraphic examination is completed.
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6.0 Additional Reports
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An interim report will be issued on November 1, 1980.
The date for submittal of the final report will be indicated at that ti!ne.
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