05000289/LER-1981-001, Forwards LER 81-001/03L-1.Detailed Event Analysis Encl

Forwards LER 81-001/03L-1.Detailed Event Analysis Encl

ML19347E302
Person / Time
Site:	Crane
Issue date:	04/20/1981
From:	Hukill H METROPOLITAN EDISON CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML19347E303	List: 05000289/LER-1981-001, Forwards LER 81-001/03L-1.Detailed Event Analysis Encl 05000289/LER-1981-001-03, /03L-1:on 810117,two Leaks Found in 1-inch Bypass Around MU-V17 During Limited Plant Heatup.Caused by Flange Socket Fillet Weld Failure Due to fabrication-induced Crack in Root of Weld
References
L1L-112, NUDOCS 8104240547
Download: ML19347E302 (2)

LER-1981-001, Forwards LER 81-001/03L-1.Detailed Event Analysis Encl

Event date:
Report date:
2891981001R00 - NRC Website

text

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e Metropolitan Edison Company Post Office Box 480 II Middletown, Pennsylvania 17057 A

717 9444 041 writer i oirect Diet Nurnoer April 20,1981 -

L1L 112 (s.; rg,,

-- i Office of Inspection & Enforcement q'.

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Attn:

B. H. Grier, Director

,A Region I A

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' U. S. Nuclear Regulatory Comission 0,

1. %?g yN 631 Park Avenue O/S King of Prussia, PA 19406

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Dear Sir:

9 m

Three Mile Island Nuclear Station, Unit 1 (TMI-1)

Operating License No. DPR-50 Docket No. 50-289 LER 81-001/03L-1 Attached please find Licensee Event Report 81-001/03L-1 which is a followup report concerning the leaks found in the make up and purification system. This event is reportable per Section 6.9.2.B(4).

Sincerely, Signed 11.D. Eukill H. D. Hukill Director, 'DiI-1 l

HDH:DGM: hah Actachments cc:

L. Barrett h

c/o Document Mgmt. Branch 1

ook hI(

Metrccci ta? Edison Comoany is a f.'emoer of tne Genera: Puche UtM tes System l

3104240547 l

FOLLOZ-UP REPORT TO TMI-1 LER 81-001/03L-1 This report presents the final evaluation for the flange socket veld and the flow instrument (MU-36-FI) float extension tube which were found to have small leaks during a limited Reactor Coolant System heatup to approximately 1900F on January 17, 1981.

The results of the metallurgical examination (abstracted from GPUN Materials Laboratory Reports #71823 and' 72031) are that the cause of

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these failures was not primarily a result of the inadvertent sulfuric acid injection to the makeup system in 1979. The leaks were evaluated to have no common mode of failure and are considered to be isolated occurrences, despite the fact that these failures occurred nearly simultaneously upon makeup system pressuritation.

The cause of the flange socket fillet veld failure was de: ermined by metallurgical analyses to be the result of a fabrication induced crack in the root of the weld which propagated under the influence of mechanical and/or thermal stresses.

The cause of the MU-36-FI float extension tube fai!ure was deter =ined by metallurgical analyses to be the result of pitting corrosion and most likely caused by stagnant conditions at the bottom of the bore of the tube which permittad the long term concentration of corrosive species, most likely chloride ions.

Design review of other flow instruments in the Makeup System identified twelve other flow instruments with float extension tubes of si=ilar design to MU-36-FI.

These instru=ents are listed below:

MU FT1 MU FT1 MU FI/FS1 MU FT2 MU FT2 MU FI/FS2 LU FT3 MU FT3 MU FI/FS3 MU FT4 MU FT4 MU FI/FS4 From the development of a float extension tube mockup, it was determined that these twelve installed flow instruments could be successfully radiographed to determine if cracks similar to that found in MU-36-FI were present. Although minor deposits were found at the bottom of some of the tubes, radiographs of the float extension tubes of these twelve flow instruments did not reveal any detectable cracking or pitting in any of the twelve float extension tubes.

Based on the final results of the metallurgical examination of the failed com-ponents and the results of the radiographs of the float extension tubes of the twelve flow instruments in the makeup system of similar design to MU-36-FI, it is concluded that these two failures were the results of isolated incidents and not indicative of any generic problem with Makeup System components.

This item is considered closed and no further action is planned, other than the repairs to the affected components as described in the previous report.