U-601073, Forwards Insp Actions Taken for Plant BWR Stainless Steel Piping,Per Generic Ltr 84-11 on Igscc.Actions Taken to Mitigate IGSCC During Const Recommended by Rev 1 to NUREG-0313

Forwards Insp Actions Taken for Plant BWR Stainless Steel Piping,Per Generic Ltr 84-11 on Igscc.Actions Taken to Mitigate IGSCC During Const Recommended by Rev 1 to NUREG-0313

ML20236P053
Person / Time
Site:	Clinton
Issue date:	11/12/1987
From:	Hall D ILLINOIS POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
RTR-NUREG-0313, RTR-NUREG-313 GL-84-11, IEB-82-03, IEB-82-3, IEB-83-02, IEB-83-2, U-601073, NUDOCS 8711170127
Download: ML20236P053 (4)

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, U-601073 1 L3 0-8 7 ( ll- 12) -L l 1A.120

/LLINDIS POWER COMPANY ,

1 CLINTON POWf.R STATION. P.O. BOX 678, CLINTON. ILLINOIS 61727 l 1

November 12, 1987 Docket No. 50-461 j Nuclear Regulatory Commission 3 l

Document Control Desk Washington, D.C. 20555 4

Subject:

Clinton Power Station Generic Letter 84-11 l Inspections of BWR Stainless Steel Piping

Dear Sir:

f Generic Letter 84-11 identifies concerns related to Intergranular Stress Corrosion Cracking (IGSCC). Illinois i Power (IP) took actions during construction of Clinton Power Station (CPS) to mitigate IGSCC as recommended in NUREG 0313, Rev. 1, Technical Report on Material Selection and Processing Guidelines for Boiling Water Reactor (BWR) Coolant Pressure i Boundary Piping. This is described in Chapter 5 of the CPS Final Safety Analysis Report (page 5.2-24) and is summarized as follows:

IP's approach to resolve IGSCC concerns includes solution annealing welded assemblies of nonresistant stainless materials, corrosion resistant cladding these materials prior to field welding, substituting resistant materials, where possible, and controlling the welding processes.

IP's response to actions required by the Generic Letter are given in the attachment.

I hereby affirm that the information in this letter is correct to the best of my knowledge.

Sincerely yours, 8711170127 871112 /

ADOCK 05000 1 . P. Ha 1

{DR Vice Presicent DPH/krm Attachment cc: B. L. Siegel, NRC Clinton Licensing Project Manager NRC Resident Inspector Regional Administrator, Region III, USNRC Illinois Department of Nuclear Safety ,

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J Pcgs 1-of 3' Response Eo Generic Letter 84-11' Actions

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-1. Generic-~L'etter Action

!A reinspection' program of piping susceptible to IGSCC should be undertaken'.. The reinspection should commence i within about; two calendar years, adjusted .to coincide with - J the'next scheduled outage, from the previous inspection performed under IE Bulletins 82-03, 83-02, or our August 26,'1983~0rder.

Response .

The IE Bulletins above..were' directed to. Licensees of 1 operating ~ boiling water reactors to-demonstrate the j effectiveness.of their detection capability of cracks on 1 stainless. steel piping (Reactor. Recirculation system), 1 susceptible.to IGSCC by-performing inspection. Holders of l j

construction permits were not required to take any-actions. Generic Letter 84-11, directed to all' Licensees H of operating reactors and construction. permits to perform j reinspection within about two calendar-years from the '

previous' inspection performed under the above IE Bulletins.

Clinton Power. Station piping susceptible to ISGCC was not put'in service until initial criticality (February 1987); 4 therefore, this' reinspection was not appropriate.

During the Pre-Service Inspection (October 1984), Illinois Power performed ultrasonic testing on all piping

-susceptible to IGSCC, utilizing procedures / examiners capable ~of detecting-IGSCC. No reportable indications were;found.. The' CPS Inservice Examination Program Plan provides the planned inspections during subsequent refueling outages. (See IP's letter dated June 22, 1987, ,

U-600963.) {

2. Generic Letter Action f These-inspections should include the following stainless steel welds, susceptible to IGSCC, in piping equal to or j greater than 4" in diameter, in systems o7erating over j 200*F, that are part of or connected to the reactor coolant pressure boundary, out to the second isolation f valve as follows.

(a) Inspection of 20% of the welds in each pipe size of q IGSCC sensitive welds not inspected previously (but i no less than 4 welds) and reinspection of 20% of the 1 welds in each pipe size inspected previously (but not  :

less than 2 welds) and found not to be cracked. This sample should be selected primarily from weld locations shown by experience to have the highest j

propensity for cracking.

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-n Page 2 of 3 (b) All unrepaired cracked welds. j (c) Inspection'of all weld overlays on welds where l' circumferential cracks longer than 10% of-circumference were measured. Disposition of any findings will be reviewed on a case-by-case basis.

Criteria for operation beyond one cycle with overlaid- '

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joints are under development.

(d) Inspection oflany weld-treated by induction heating stress improvement which has not been post treatment UT' acceptance tested, j (e) In.the event new cracks or significant growth of old '

cracks are found, the inspection scope should be expanded in accordance with IEB 83-02.

Response:  !

~ Bulletins 82-03 and 83-02 and Genaric Letter 84-11 Thc were atrected to Licensees of operating boiling water  ;

reactors to perform ultrasonic (UT) inspection on piping susceptible to IGSCC utilizing Electric Power Research Institute (EPRI) qualified procedures and examiners, since ,

EPRI qualified procedures and examiners were not utilized  !

during their prior inspections. These inspections were i one time inspections. Illinois Power Company has performed the preservice inspection on all piping welds (100%) susceptible to IGSCC utilizing EPRI qualified procedures and examiners. Reinspection of the sample welds specified above is not appropriate for Clinton Power Station for the reasons described above and in response 1.

During the subsequent first 10-year inservice inspection interval 25% of the total welds as required by the ASME Section XI, 1980 Edition through Winter 1981 Addenda,.will be reinspected. If unacceptable indications / cracks are discovered at CPS, Illinois Power Company will take further action to revise the plan or make repairs as described in response 5.

3. Generic Letter Action All level 2 and level 3 UT examiners should demonstrate competence in accordance with IEB 83-02 and level 1 examiners should demonstrate field performance capability.

Response

UT examiners who performed the preservice inspection of pioing susceptible to IGSCC were EPRI qualified. During subsequent inservice inspection of this piping, only EPRI qualified level 2 and 3 UT examiners will be utilized.

Level 1 examiners who may become qualified by ';

demonstrating field performance capability will not be utilized on these piping inspections. The Inservice Examination Program Plan will be revised prior to the' first refueling outage to reflect this commitment.

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4. Generic Letter Action Leak detection'and leakage limits should be sufficiently restrictive to' ensure timely investigation of unidentified leakage.

Response

Clinton Power Station's Code Class 1, 2, and 3 pressure boundary piping. meets the guidelines of Part III of NUREG 0313, Rev. 1. CPS Technical Specification limits on unidentified leakage are sufficiently restrictive to ensure timely investigation of unidentified leakage.

-5. Generic Letter' Action Crack evaluation and repair criteria are given in Attachment 2 of the Generic Letter.

Response

The nuclear inductry is= involved in research evolutions to determine better techniques for IGSCC crack evaluation and repair methods. If unacceptable indications / cracks are discovered at CPS, Illinois Power Company will evaluate and take appropriate remedial measures, including repairs and/or revising the program plan to expand the scope, utilizing techniques available at that time and recognized by the Nuclear Regulatory Commission.

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