ML20087L385

Submits Plan for Insp & Repair of Intergranular Stress Corrosion Cracking Indications in Stainless Steel Piping in Drywell During Refueling Outage Initiated on 840306

ML20087L385
Person / Time
Site:	Quad Cities
Issue date:	03/19/1984
From:	Rybak B COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
8311N, NUDOCS 8403270175
Download: ML20087L385 (4)

Text

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' N fConwnonwealth Edison One First N1tional Plaza, Chicago, litinois O' , Address Reply to: Post Office Box 767

%  : Chicago, Illinois 60690 March 19, 1984 x

Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation -

U.S.; Nuclear Regulatory Commission Washington,iDC' 20555-

Subject:

Quad Cities Station Unit 1

-IGSCC Inspection and Repair Plan During Refueling Outage

. March, 1984 NRC Docket No. 50-254

Dear Mr; Denton:

. .Following is the plan for' inspection-and. repair of-stainless steel; piping.in the Unit 1 drywell during the refueling outage that started March 6, 1984.

1. A decontamination-of the recirculation system piping will.be made using the services of London' Nuclear.

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2. Induction Heating Stress Improvement (IHSI) will be applied to all the recirculation system piping welds. Some welds ~may not be treated due to the unavailability of heating coils and/or

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inaccessibility. In. addition IHSI will be-applied on branch system piping out to the first= isolation valve. The Station will determine the extent of IHSI application to the brench' system piping.

3. It-is not planned,to ultrasonically inspect (UT) any welds prior to IHSI application. All welds - treated by IHSI will be UT-examined after treatment.

LA.. The. attached inspection' plan addresses the requirements of

SECY- 83-267C f or ' Quad Cities Unit 1.

Tne 19 welds in the

recirculation' system'not planned for examination. These welds include 8 potentially high radiation level Riser Inlet Safe End-to-Nozzle Welds, an Outlet Safe End-to-Nozzle Weld, and 6

_ . solution annealed sweepoletato-header welds. The two-solution annealed,.28" cross-to-reducer welds.will be inspected.

The SECY recognizes that the risk'of IGSCCi 's increased'for

temperature above 2000F. The welds to be examined'in the Residual Heat Removal and Core Spray. systems.are strongly biased

~to the highest temperature. portions of these systems.

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March 19, 1984 H.-R. Denton If cracks are found within the inspected sample of a specific piping system and size, an equivalent sample of that system and size will be inspected. For purposes of sample expansion, the Safe End-to-Nozzle welds on the Recirculation Inlet and' Outlet piping.and the Sweepolet-to-Header welds will be treated as categories separate from the other welds in those piping runs.

5. The NDE contracts performing UT' inspection will be Lambert, MacGill and Thomas (LMT) and Universal Testing Laboratories

-(UTL) - Kraft Werke Union (KWU). The Level II and III UT personnel performing evaluations of crack indications were

. qualified at the EPRI NDE Center by successfully performing the

-practical (83-02) examination. Level I and II UT personnel performing scanning duties will be trained by the contractor on site._ Results of the contractor examinations will be provided to CECO. NDE personnel for review and ultimate resolution.

These CECO personnel were qualified by the practical (83-02)

. examination at the NDE Center. The KWU creeping' wave technique will be used for discrimination of all welds having circumferential. crack indications.

6. Each crack ~ indication will be' evaluated to determine whether any repair is necessary.

Where applicable, credit will be taken for having applied IHSI in performing a crack growth analysis.

All welds with an axial crack will have an overlay repair applied. The overlay thickness, which.is a function of crack depth, crack length, and applied stresses, will be sufficient to provide full IWB-3640 margin. The ratio of twice the measured

. flaw size to-the allowable flaw size is used to determine the overlay thickness. In accordance.with the ACRS letter dated December 19, 1983 for cracks with continuous indication for a

circumferential extent greater than 1200, the overlay design will be based on assuming the depth to be through-wall.

The crack evaluation and repair criteria meet all the requirements of ASME Sec. XI IWB-3640 and SECY 83-267C with the exception'that means other than dye penetrant (PT), i.e. video monitoring and-taping are utilized to assure integrity of the first wald overlay layer. This alternate is used since PT has the potential for introducing weld defects.

This inspection and repair plan for Quad Cities Station Unit 1 is being_provided to you prior to the start of our inspection program.

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Ji.i R. . Denton --3 - March 19, 1984 If you have any questions on any portion of-this program, please contact this office.

One: signed' original and forty (40) copies of this letter and its cttachment are provided for your use.

.Very truly yours, 8

B. R Nuclear Licensing Administrator 1m' cc: R. Bevan - NRR NRC Resident Inspector - Quad Cities Attachment 8311N

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{ .w' Inspection Plan .

Stainless Steel Piping Susceptible to IGSCC -]

4" and Grcater Diameter ,

Quad Cities Unit 1 Spring 1984

' System- 1 Total ~ l Welds To Be l Inaccessible 3 To Be Examined l Welds l Examined 1 Welds l-

. 1. 1 I

, Recirculation'- 'l- l l Risers (12") .I 42 1 422 l SE/ Nozzle' l 10 1 2 .l Ring Header (22")l 12 1 122 l Sweepolet/Hdr l 8 l 2 l Outlets (28") 1 32 1 322 l SE/ Nozzle 1 2- l 1 I Bypass Stubs (4")l '

8 l 4 l l .I I Residual Heat - l l l Removal- .

l l l

-LPCI (16") -l 32 l 92 1 2 SD Cooling (20") l 17 1 1 52 l 1 Head Spray (4") i 13 l 4 l 1 1 I I Core Spray (10") l 32 1 7 2 1 - I Reactor Water l

.. Clean Up-(6") l- 7 , 4 i 3 1 -1 I Head Vent'(4") l 2 l 2 l l l l CRD Return (4") -l 3 'l -3 l 1 Based on SECY-83-267C, Attachment B.

2'. Includes Welds'in the IHSI Scope. The number of welds examined could be reduced if fewer welds are IHSI treated; however minimum sample will be at least-20%.

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. 3 The number of inaccessible welds could increase upon specific review.of conditions affecting inspectability.

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